To see the other types of publications on this topic, follow the link: Transfert de mitochondries.
Journal articles on the topic 'Transfert de mitochondries'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Transfert de mitochondries.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
GUEGUEN, N., L. LEFAUCHEUR, and P. HERPIN. "Relations entre fonctionnement mitochondrial et types contractiles des fibres musculaires." INRAE Productions Animales 19, no. 4 (September 13, 2006): 265–78. http://dx.doi.org/10.20870/productions-animales.2006.19.4.3494.
Full textAbstract:
Le muscle, tissu d’importance économique majeure chez les animaux producteurs de viande, est un tissu composite comprenant en majeure partie des fibres musculaires qui constituent une population très hétérogène aux caractéristiques contractiles et métaboliques variées. Les relations entre type contractile des fibres et fonctionnement mitochondrial, un composant essentiel du métabolisme énergétique musculaire, restent mal connues. Leur compréhension est pourtant essentielle pour espérer mieux maîtriser l’impact du type de fibres sur les diverses composantes de la qualité de la viande. Une analyse fine de la composante mitochondriale du fonctionnement énergétique des fi-bres a donc été entreprise en relation avec leurs caractéristiques contractiles. Les résultats indiquent que, contrairement aux fibres rapides de types IIX et IIB, la régulation mitochondriale dans les fibres lentes de type I et, dans une moindre mesure, de type rapide IIA est hautement spécialisée avec une optimisation de l’efficacité des mitochondries (couplage entre oxydation et phosphorylation, capacité oxydative maximale), une restriction de leur perméabilité à l’ADP et un couplage fonctionnel entre les kinases mitochondriales et la production d’ATP, permettant un transfert efficace de l’énergie vers les myosines. De plus, la régulation mitochondriale et les transferts énergétiques sont modulés par l’activation calcium-dépendante des ATPases portées par les myosines.
2
Lin, Tsu-Kung, Shang-Der Chen, Yao-Chung Chuang, Min-Yu Lan, Jiin-Haur Chuang, Pei-Wen Wang, Te-Yao Hsu, et al. "Mitochondrial Transfer of Wharton’s Jelly Mesenchymal Stem Cells Eliminates Mutation Burden and Rescues Mitochondrial Bioenergetics in Rotenone-Stressed MELAS Fibroblasts." Oxidative Medicine and Cellular Longevity 2019 (May 22, 2019): 1–17. http://dx.doi.org/10.1155/2019/9537504.
Full textAbstract:
Wharton’s jelly mesenchymal stem cells (WJMSCs) transfer healthy mitochondria to cells harboring a mitochondrial DNA (mtDNA) defect. Mitochondrial myopathy, encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is one of the major subgroups of mitochondrial diseases, caused by the mt.3243A>G point mutation in the mitochondrial tRNALeu(UUR) gene. The specific aim of the study is to investigate whether WJMSCs exert therapeutic effect for mitochondrial dysfunction in cells of MELAS patient through donating healthy mitochondria. We herein demonstrate that WJMSCs transfer healthy mitochondria into rotenone-stressed fibroblasts of a MELAS patient, thereby eliminating mutation burden and rescuing mitochondrial functions. In the coculture system in vitro study, WJMSCs transferred healthy mitochondria to rotenone-stressed MELAS fibroblasts. By inhibiting actin polymerization to block tunneling nanotubes (TNTs), the WJMSC-conducted mitochondrial transfer was abrogated. After mitochondrial transfer, the mt.3243A>G mutation burden of MELAS fibroblasts was reduced to an undetectable level, with long-term retention. Sequencing results confirmed that the transferred mitochondria were donated from WJMSCs. Furthermore, mitochondrial transfer of WJMSCs to MELAS fibroblasts improves mitochondrial functions and cellular performance, including protein translation of respiratory complexes, ROS overexpression, mitochondrial membrane potential, mitochondrial morphology and bioenergetics, cell proliferation, mitochondrion-dependent viability, and apoptotic resistance. This study demonstrates that WJMSCs exert bioenergetic therapeutic effects through mitochondrial transfer. This finding paves the way for the development of innovative treatments for MELAS and other mitochondrial diseases.
3
Fu, Ailing. "Mitotherapy as a Novel Therapeutic Strategy for Mitochondrial Diseases." Current Molecular Pharmacology 13, no. 1 (January 15, 2020): 41–49. http://dx.doi.org/10.2174/1874467212666190920144115.
Full textAbstract:
Background: The mitochondrion is a multi-functional organelle that is mainly responsible for energy supply in the mammalian cells. Over 100 human diseases are attributed to mitochondrial dysfunction. Mitochondrial therapy (mitotherapy) aims to transfer functional exogenous mitochondria into mitochondria-defective cells for recovery of the cell viability and consequently, prevention of the disease progress. Conclusion: Mitotherapy makes the of modulation of cell survival possible, and it would be a potential therapeutic strategy for mitochondrial diseases. Objective: The review summarizes the evidence on exogenous mitochondria that can directly enter mammalian cells for disease therapy following local and intravenous administration, and suggests that when healthy cells donate their mitochondria to damaged cells, the mitochondrial transfer between cells serve as a new mode of cell rescue. Then the transferred mitochondria play their roles in recipient cells, including energy production and maintenance of cell function.
4
Adams, Keith L., Monica Rosenblueth, Yin-Long Qiu, and Jeffrey D. Palmer. "Multiple Losses and Transfers to the Nucleus of Two Mitochondrial Succinate Dehydrogenase Genes During Angiosperm Evolution." Genetics 158, no. 3 (July 1, 2001): 1289–300. http://dx.doi.org/10.1093/genetics/158.3.1289.
Full textAbstract:
Abstract Unlike in animals, the functional transfer of mitochondrial genes to the nucleus is an ongoing process in plants. All but one of the previously reported transfers in angiosperms involve ribosomal protein genes. Here we report frequent transfer of two respiratory genes, sdh3 and sdh4 (encoding subunits 3 and 4 of succinate dehydrogenase), and we also show that these genes are present and expressed in the mitochondria of diverse angiosperms. Southern hybridization surveys reveal that sdh3 and sdh4 have been lost from the mitochondrion about 40 and 19 times, respectively, among the 280 angiosperm genera examined. Transferred, functional copies of sdh3 and sdh4 were characterized from the nucleus in four and three angiosperm families, respectively. The mitochondrial targeting presequences of two sdh3 genes are derived from preexisting genes for anciently transferred mitochondrial proteins. On the basis of the unique presequences of the nuclear genes and the recent mitochondrial gene losses, we infer that each of the seven nuclear sdh3 and sdh4 genes was derived from a separate transfer to the nucleus. These results strengthen the hypothesis that angiosperms are experiencing a recent evolutionary surge of mitochondrial gene transfer to the nucleus and reveal that this surge includes certain respiratory genes in addition to ribosomal protein genes.
5
Gao, Junjie, An Qin, Delin Liu, Rui Ruan, Qiyang Wang, Jun Yuan, Tak Sum Cheng, et al. "Endoplasmic reticulum mediates mitochondrial transfer within the osteocyte dendritic network." Science Advances 5, no. 11 (November 2019): eaaw7215. http://dx.doi.org/10.1126/sciadv.aaw7215.
Full textAbstract:
Mitochondrial transfer plays a crucial role in the regulation of tissue homeostasis and resistance to cancer chemotherapy. Osteocytes have interconnecting dendritic networks and are a model to investigate its mechanism. We have demonstrated, in primary murine osteocytes with photoactivatable mitochondria (PhAM)floxed and in MLO-Y4 cells, mitochondrial transfer in the dendritic networks visualized by high-resolution confocal imaging. Normal osteocytes transferred mitochondria to adjacent metabolically stressed osteocytes and restored their metabolic function. The coordinated movement and transfer of mitochondria within the dendritic network rely on contact between the endoplasmic reticulum (ER) and mitochondria. Mitofusin 2 (Mfn2), a GTPase that tethers ER to mitochondria, predominantly mediates the transfer. A decline in Mfn2 expression with age occurs concomitantly with both impaired mitochondrial distribution and transfer in the osteocyte dendritic network. These data show a previously unknown function of ER-mitochondrial contact in mediating mitochondrial transfer and provide a mechanism to explain the homeostasis of osteocytes.
6
Zampieri, Luca X., Catarina Silva-Almeida, Justin D. Rondeau, and Pierre Sonveaux. "Mitochondrial Transfer in Cancer: A Comprehensive Review." International Journal of Molecular Sciences 22, no. 6 (March 23, 2021): 3245. http://dx.doi.org/10.3390/ijms22063245.
Full textAbstract:
Depending on their tissue of origin, genetic and epigenetic marks and microenvironmental influences, cancer cells cover a broad range of metabolic activities that fluctuate over time and space. At the core of most metabolic pathways, mitochondria are essential organelles that participate in energy and biomass production, act as metabolic sensors, control cancer cell death, and initiate signaling pathways related to cancer cell migration, invasion, metastasis and resistance to treatments. While some mitochondrial modifications provide aggressive advantages to cancer cells, others are detrimental. This comprehensive review summarizes the current knowledge about mitochondrial transfers that can occur between cancer and nonmalignant cells. Among different mechanisms comprising gap junctions and cell-cell fusion, tunneling nanotubes are increasingly recognized as a main intercellular platform for unidirectional and bidirectional mitochondrial exchanges. Understanding their structure and functionality is an important task expected to generate new anticancer approaches aimed at interfering with gains of functions (e.g., cancer cell proliferation, migration, invasion, metastasis and chemoresistance) or damaged mitochondria elimination associated with mitochondrial transfer.
7
Peng, Wesley, Yvette C. Wong, and Dimitri Krainc. "Mitochondria-lysosome contacts regulate mitochondrial Ca2+dynamics via lysosomal TRPML1." Proceedings of the National Academy of Sciences 117, no. 32 (July 23, 2020): 19266–75. http://dx.doi.org/10.1073/pnas.2003236117.
Full textAbstract:
Mitochondria and lysosomes are critical for cellular homeostasis, and dysfunction of both organelles has been implicated in numerous diseases. Recently, interorganelle contacts between mitochondria and lysosomes were identified and found to regulate mitochondrial dynamics. However, whether mitochondria–lysosome contacts serve additional functions by facilitating the direct transfer of metabolites or ions between the two organelles has not been elucidated. Here, using high spatial and temporal resolution live-cell microscopy, we identified a role for mitochondria–lysosome contacts in regulating mitochondrial calcium dynamics through the lysosomal calcium efflux channel, transient receptor potential mucolipin 1 (TRPML1). Lysosomal calcium release by TRPML1 promotes calcium transfer to mitochondria, which was mediated by tethering of mitochondria–lysosome contact sites. Moreover, mitochondrial calcium uptake at mitochondria–lysosome contact sites was modulated by the outer and inner mitochondrial membrane channels, voltage-dependent anion channel 1 and the mitochondrial calcium uniporter, respectively. Since loss of TRPML1 function results in the lysosomal storage disorder mucolipidosis type IV (MLIV), we examined MLIV patient fibroblasts and found both altered mitochondria–lysosome contact dynamics and defective contact-dependent mitochondrial calcium uptake. Thus, our work highlights mitochondria–lysosome contacts as key contributors to interorganelle calcium dynamics and their potential role in the pathophysiology of disorders characterized by dysfunctional mitochondria or lysosomes.
8
SHIAO, Young-Ji, Bénédicte BALCERZAK, and Jean E. VANCE. "A mitochondrial membrane protein is required for translocation of phosphatidylserine from mitochondria-associated membranes to mitochondria." Biochemical Journal 331, no. 1 (April 1, 1998): 217–23. http://dx.doi.org/10.1042/bj3310217.
Full textAbstract:
The mechanism of import of phosphatidylserine (PtdSer) into mitochondria was investigated using a reconstituted system of isolated organelles in vitroin which PtdSer was translocated from donor membranes to mitochondria and was decarboxylated therein. Neither phosphatidylcholine nor phosphatidylethanolamine (PtdEtn) was translocated under the same conditions. Transfer of PtdSer from its site of synthesis on the endoplasmic reticulum and mitochondria-associated membranes [J. E. Vance (1990) J. Biol. Chem. 265, 7248–7256] to its site of decarboxylation on mitochondrial inner membranes is predicted to be mediated by membrane contact. A mitochondrial membrane protein appears to be involved in the translocation event since proteolysis of proteins exposed on the mitochondrial surface potently inhibited PtdSer transfer, whereas proteolysis of surface proteins of mitochondria-associated membranes did not impair the transfer. The nature of the membranes that donate PtdSer to mitochondria in vitrois not crucial since PtdSer of mitochondria-associated membranes, endoplasmic reticulum and microsomes was decarboxylated to PtdEtn with approximately equal efficiency. The translocation of PtdSer to mitochondria was stimulated by magnesium and calcium ions and was inhibited by incubation of mitochondria with sulphydryl group-modifying reagents. Reconstitution of PtdSer translocation/decarboxylation using digitonin-solubilized mitochondria and PtdSer-donor membranes suggested that the putative PtdSer-translocation protein is primarily localized to contract sites between mitochondrial inner and outer membranes. These studies provide evidence for the involvement of a mitochondrial membrane protein in the import of newly-synthesized PtdSer into mitochondria.
9
Chuang, Yao-Chung, Chia-Wei Liou, Shang-Der Chen, Pei-Wen Wang, Jiin-Haur Chuang, Mao-Meng Tiao, Te-Yao Hsu, Hung-Yu Lin, and Tsu-Kung Lin. "Mitochondrial Transfer from Wharton’s Jelly Mesenchymal Stem Cell to MERRF Cybrid Reduces Oxidative Stress and Improves Mitochondrial Bioenergetics." Oxidative Medicine and Cellular Longevity 2017 (2017): 1–22. http://dx.doi.org/10.1155/2017/5691215.
Full textAbstract:
Myoclonus epilepsy associated with ragged-red fibers (MERRF) is a maternally inherited mitochondrial disease affecting neuromuscular functions. Mt.8344A>G mutation in mitochondrial DNA (mtDNA) is the most common cause of MERRF syndrome and has been linked to an increase in reactive oxygen species (ROS) level and oxidative stress, as well as impaired mitochondrial bioenergetics. Here, we tested whether WJMSC has therapeutic potential for the treatment of MERRF syndrome through the transfer of mitochondria. The MERRF cybrid cells exhibited a high mt.8344A>G mutation ratio, enhanced ROS level and oxidative damage, impaired mitochondrial bioenergetics, defected mitochondria-dependent viability, exhibited an imbalance of mitochondrial dynamics, and are susceptible to apoptotic stress. Coculture experiments revealed that mitochondria were intercellularly conducted from the WJMSC to the MERRF cybrid. Furthermore, WJMSC transferred mitochondria exclusively to cells with defective mitochondria but not to cells with normal mitochondria. MERRF cybrid following WJMSC coculture (MF+WJ) demonstrated improvement of mt.8344A>G mutation ratio, ROS level, oxidative damage, mitochondrial bioenergetics, mitochondria-dependent viability, balance of mitochondrial dynamics, and resistance against apoptotic stress. WJMSC-derived mitochondrial transfer and its therapeutic effect were noted to be blocked by F-actin depolymerizing agent cytochalasin B. Collectively, the WJMSC ability to rescue cells with defective mitochondrial function through donating healthy mitochondria may lead to new insights into the development of more efficient strategies to treat diseases related to mitochondrial dysfunction.
10
Singh, Abhishek K., Karin Golan, Mark J. Althoff, Ekaterina Petrovich-Kopitman, Ashley M. Wellendorf, Fatima Mohmoud, Mayla Bertagna, et al. "Bone Marrow Hematopoietic Connexin 43 Is Required for Mitotransfer and AMPK Dependent Mesenchymal Microenvironment Regeneration after Irradiation." Blood 132, Supplement 1 (November 29, 2018): 872. http://dx.doi.org/10.1182/blood-2018-99-118292.
Full textAbstract:
Abstract Hematopoietic stem cell/progenitor (HSCP) transplantation (HSCT) is routinely used for the treatment of cancer and inborn hematopoietic defects. The bone marrow (BM) microenvironment (ME) is a major regulator of hematopoietic function and fate. Clinical data supports osteoblastic regeneration after HSCT despite the inability of BM mesenchymal stem cells (BM-MSC) to engraft. Therefore, understanding the hematopoietic-dependent mechanisms controlling ME mesenchymal regeneration is expected to provide molecular targets for intervention in the context of HSCT. Hematopoietic connexin-43 (H-Cx43) mediates HSCP survival and efficient blood formation by scavenging damaging excess reactive oxygen species (ROS) through transfer to BM mesenchymal stromal cells (BM-MSC) after chemotherapy, preventing lethal hematopoietic failure (Taniguchi-Ishikwawa E et al., PNAS 2012), while the expression of Cx43 on BM-MSC regulates CXCL12 secretion and HSCP homeostasis (Schajnovitz A et al., Nat. Immunol., 2011). Since Cx43 is expressed in mitochondria, we hypothesized that H-Cx43 mediated ROS transfer upon stress depends on hematopoietic mitochondria transfer and uptake by the BM-MSC. We created chimeric mice by transplanting Vav1-CreTg/-, Cox8 mitochondrial localization signal-Dendra2Tg/- wild-type (mDendra2/WT) or Cx43fl/fl(mDendra2/Cx43Δ/Δ) HSCP to lethally irradiated, congenic WT mice and assessed the recovery of stromal cell regeneration via transfer of mitochondria to BM-MSC. H-Cx43Δ/Δchimeric mice have delayed lympho-hematopoietic recovery after irradiation or chemotherapy which can be reversed by restoration of hematopoietic Cx43 expression. H-Cx43Δ/Δchimeric mice exhibit decreased (~60-80%) and delayed colony-forming-unit-fibroblast (CFU-F) and osteoblast (CFU-Ob) regeneration and hematopoietic recovery. The delayed hematopoietic response in H-Cx43Δ/Δchimeras associated with ~40% reduction in mitochondrial transfer from HSCP to Lin-/CD45-/PDGFRα+/Sca1- BM stromal cells (MSC/P). Reverse transplantation experiments indicate that stromal Cx43 is dispensable for mitochondrial transfer from BM stroma to HSCP. Impaired mitochondrial uptake in H-Cx43Δ/Δchimeras associated with ~30-40% decreased mitochondrial ROS (mROS), membrane potential (MMP) and proliferation (assessed by in vivo BrdU uptake) of recipient MSC/P, suggesting that the transferred mitochondria reprogram the recipient mesenchymal progenitor metabolism. Defects of mitotransfer from H-Cx43Δ/ΔHSCP to BM MSC/P and in recipient BM MSC/P mitochondrial activity were recapitulated in in vitro co-cultures. Interestingly, intracellular [ATP] is upregulated (~2 fold) in MSC/P from chimeric H-Cx43Δ/ΔBM that received donor-derived mitochondria, as compared to donor mitochondria containing MSC/P from WTchimeras. Hemichannel opening causes loss of ATP, we therefore speculated that ATP released from MSC/P upon irradiation and transplantation is uptaken by HSPC, activating mitochondrial transfer as part of BM regeneration. Forced glycolysis-dependent restoration of [ATP] in MSC/P but not in HSCP enhances transfer of mitochondria from HSCP to MSC/P, suggesting that BM stromal [ATP] is an irradiation-responsive positive regulator of mitochondria transfer. Hemichannel-derived exogenous ATP suppresses AMPK activation, which regulates cellular metabolic homeostasis by modulating mitochondrial ROS, mitochondria dynamics and the fate of mitochondria. We found that MSC/P recipient of H-Cx43Δ/Δ mitochondria have increased AMPK activity as assessed by increased phosphorylation of AMPK and its downstream effectors ULK1 and ACC (~2-fold) when compared with MSC/P recipient of H-WT mitochondria, whereas MSC/P containing no donor-derived mitochondria from either chimeric mice are insensitive to the effect of Cx43 deficiency. In vivo administration of the AMPK inhibitor BML-275 dramatically increased the mitochondria transfer from HSCP to MSC/P in WT and H-Cx43Δ/Δ chimeras, and completely restores the negative effect of H-Cx43 deficiency on BM mesenchymal and hematopoietic regeneration. Our data indicate that hematopoietic mitochondrial Cx43 is required to control both mitochondrial transfer and BM ME energetic balance and regeneration after myeloablative irradiation. Disclosures No relevant conflicts of interest to declare.
11
Valenti, Daniela, Rosa Anna Vacca, Loredana Moro, and Anna Atlante. "Mitochondria Can Cross Cell Boundaries: An Overview of the Biological Relevance, Pathophysiological Implications and Therapeutic Perspectives of Intercellular Mitochondrial Transfer." International Journal of Molecular Sciences 22, no. 15 (August 2, 2021): 8312. http://dx.doi.org/10.3390/ijms22158312.
Full textAbstract:
Mitochondria are complex intracellular organelles traditionally identified as the powerhouses of eukaryotic cells due to their central role in bioenergetic metabolism. In recent decades, the growing interest in mitochondria research has revealed that these multifunctional organelles are more than just the cell powerhouses, playing many other key roles as signaling platforms that regulate cell metabolism, proliferation, death and immunological response. As key regulators, mitochondria, when dysfunctional, are involved in the pathogenesis of a wide range of metabolic, neurodegenerative, immune and neoplastic disorders. Far more recently, mitochondria attracted renewed attention from the scientific community for their ability of intercellular translocation that can involve whole mitochondria, mitochondrial genome or other mitochondrial components. The intercellular transport of mitochondria, defined as horizontal mitochondrial transfer, can occur in mammalian cells both in vitro and in vivo, and in physiological and pathological conditions. Mitochondrial transfer can provide an exogenous mitochondrial source, replenishing dysfunctional mitochondria, thereby improving mitochondrial faults or, as in in the case of tumor cells, changing their functional skills and response to chemotherapy. In this review, we will provide an overview of the state of the art of the up-to-date knowledge on intercellular trafficking of mitochondria by discussing its biological relevance, mode and mechanisms underlying the process and its involvement in different pathophysiological contexts, highlighting its therapeutic potential for diseases with mitochondrial dysfunction primarily involved in their pathogenesis.
12
Gurdon, Csanad, Zora Svab, Yaping Feng, Dibyendu Kumar, and Pal Maliga. "Cell-to-cell movement of mitochondria in plants." Proceedings of the National Academy of Sciences 113, no. 12 (March 7, 2016): 3395–400. http://dx.doi.org/10.1073/pnas.1518644113.
Full textAbstract:
We report cell-to-cell movement of mitochondria through a graft junction. Mitochondrial movement was discovered in an experiment designed to select for chloroplast transfer from Nicotiana sylvestris into Nicotiana tabacum cells. The alloplasmic N. tabacum line we used carries Nicotiana undulata cytoplasmic genomes, and its flowers are male sterile due to the foreign mitochondrial genome. Thus, rare mitochondrial DNA transfer from N. sylvestris to N. tabacum could be recognized by restoration of fertile flower anatomy. Analyses of the mitochondrial genomes revealed extensive recombination, tentatively linking male sterility to orf293, a mitochondrial gene causing homeotic conversion of anthers into petals. Demonstrating cell-to-cell movement of mitochondria reconstructs the evolutionary process of horizontal mitochondrial DNA transfer and enables modification of the mitochondrial genome by DNA transmitted from a sexually incompatible species. Conversion of anthers into petals is a visual marker that can be useful for mitochondrial transformation.
13
Feng, Gaomin, Beibei Liu, Jinghang Li, Tianlei Cheng, Zhanglong Huang, Xianhua Wang, and Heping (Peace) Cheng. "Mitoflash biogenesis and its role in the autoregulation of mitochondrial proton electrochemical potential." Journal of General Physiology 151, no. 6 (March 15, 2019): 727–37. http://dx.doi.org/10.1085/jgp.201812176.
Full textAbstract:
Respiring mitochondria undergo an intermittent electrical and chemical excitation called mitochondrial flash (mitoflash), which transiently uncouples mitochondrial respiration from ATP production. How a mitoflash is generated and what specific role it plays in bioenergetics remain incompletely understood. Here, we investigate mitoflash biogenesis in isolated cardiac mitochondria by varying the respiratory states and substrate supply and by dissecting the involvement of different electron transfer chain (ETC) complexes. We find that robust mitoflash activity occurs once mitochondria are electrochemically charged by state II/IV respiration (i.e., no ATP synthesis at Complex V), regardless of the substrate entry site (Complex I, Complex II, or Complex IV). Inhibiting forward electron transfer abolishes, while blocking reverse electron transfer generally augments, mitoflash production. Switching from state II/IV to state III respiration, to allow for ATP synthesis at Complex V, markedly diminishes mitoflash activity. Intriguingly, when mitochondria are electrochemically charged by the ATPase activity of Complex V, mitoflashes are generated independently of ETC activity. These findings suggest that mitoflash biogenesis is mechanistically linked to the build up of mitochondrial electrochemical potential rather than ETC activity alone, and may functionally counteract overcharging of the mitochondria and hence serve as an autoregulator of mitochondrial proton electrochemical potential.
14
Brenner, Carol A., H. Michael Kubisch, and Kenneth E. Pierce. "Role of the mitochondrial genome in assisted reproductive technologies and embryonic stem cell-based therapeutic cloning." Reproduction, Fertility and Development 16, no. 7 (2004): 743. http://dx.doi.org/10.1071/rd04107.
Full textAbstract:
Mitochondria play a pivotal role in cellular metabolism and are important determinants of embryonic development. Mitochondrial function and biogenesis rely on an intricate coordination of regulation and expression of nuclear and mitochondrial genes. For example, several nucleus-derived transcription factors, such as mitochondrial transcription factor A, are required for mitochondrial DNA replication. Mitochondrial inheritance is strictly maternal while paternally-derived mitochondria are selectively eliminated during early embryonic cell divisions. However, there are reports from animals as well as human patients that paternal mitochondria can occasionally escape elimination, which in some cases has led to severe pathologies. The resulting existence of different mitochondrial genomes within the same cell has been termed mitochondrial heteroplasmy. The increasing use of invasive techniques in assisted reproduction in humans has raised concerns that one of the outcomes of such techniques is an increase in the incidence of mitochondrial heteroplasmy. Indeed, there is evidence that heteroplasmy is a direct consequence of ooplasm transfer, a technique that was used to ‘rescue’ oocytes from older women by injecting ooplasm from young oocytes. Mitochondria from donor and recipient were found in varying proportions in resulting children. Heteroplasmy is also a byproduct of nuclear transfer, as has been shown in studies on cloned sheep, cattle and monkeys. As therapeutic cloning will depend on nuclear transfer into oocytes and the subsequent generation of embryonic stem cells from resulting blastocysts, the prospect of mitochondrial heteroplasmy and its potential problems necessitate further studies in this area.
15
Tilly, Jonathan L., and Dori C. Woods. "The obligate need for accuracy in reporting preclinical studies relevant to clinical trials: autologous germline mitochondrial supplementation for assisted human reproduction as a case study." Therapeutic Advances in Reproductive Health 14 (January 2020): 263349412091735. http://dx.doi.org/10.1177/2633494120917350.
Full textAbstract:
A now large body of work has solidified the central role that mitochondria play in oocyte development, fertilization, and embryogenesis. From these studies, a new technology termed autologous germline mitochondrial energy transfer was developed for improving pregnancy success rates in assisted reproduction. Unlike prior clinical studies that relied on the use of donor, or nonautologous, mitochondria for microinjection into eggs of women with a history of repeated in vitro fertilization failure to enhance pregnancy success, autologous germline mitochondrial energy transfer uses autologous mitochondria collected from oogonial stem cells of the same woman undergoing the fertility treatment. Initial trials of autologous germline mitochondrial energy transfer during - in vitro fertilization at three different sites with a total of 104 patients indicated a benefit of the procedure for improving pregnancy success rates, with the birth of children conceived through the inclusion of autologous germline mitochondrial energy transfer during in vitro fertilization. However, a fourth clinical study, consisting of 57 patients, failed to show a benefit of autologous germline mitochondrial energy transfer– in vitro fertilization versus in vitro fertilization alone for improving cumulative live birth rates. Complicating this area of work further, a recent mouse study, which claimed to test the long-term safety of autologous mitochondrial supplementation during in vitro fertilization, raised concerns over the use of the procedure for reproduction. However, autologous mitochondria were not actually used for preclinical testing in this mouse study. The unwarranted fears that this new study’s erroneous conclusions could cause in women who have become pregnant through the use of autologous germline mitochondrial energy transfer during- in vitro fertilization highlight the critical need for accurate reporting of preclinical work that has immediate bearing on human clinical studies.
16
Lipper, Colin H., Jason T. Stofleth, Fang Bai, Yang-Sung Sohn, Susmita Roy, Ron Mittler, Rachel Nechushtai, José N. Onuchic, and Patricia A. Jennings. "Redox-dependent gating of VDAC by mitoNEET." Proceedings of the National Academy of Sciences 116, no. 40 (September 16, 2019): 19924–29. http://dx.doi.org/10.1073/pnas.1908271116.
Full textAbstract:
MitoNEET is an outer mitochondrial membrane protein essential for sensing and regulation of iron and reactive oxygen species (ROS) homeostasis. It is a key player in multiple human maladies including diabetes, cancer, neurodegeneration, and Parkinson’s diseases. In healthy cells, mitoNEET receives its clusters from the mitochondrion and transfers them to acceptor proteins in a process that could be altered by drugs or during illness. Here, we report that mitoNEET regulates the outer-mitochondrial membrane (OMM) protein voltage-dependent anion channel 1 (VDAC1). VDAC1 is a crucial player in the cross talk between the mitochondria and the cytosol. VDAC proteins function to regulate metabolites, ions, ROS, and fatty acid transport, as well as function as a “governator” sentry for the transport of metabolites and ions between the cytosol and the mitochondria. We find that the redox-sensitive [2Fe-2S] cluster protein mitoNEET gates VDAC1 when mitoNEET is oxidized. Addition of the VDAC inhibitor 4,4′-diisothiocyanatostilbene-2,2′-disulfonate (DIDS) prevents both mitoNEET binding in vitro and mitoNEET-dependent mitochondrial iron accumulation in situ. We find that the DIDS inhibitor does not alter the redox state of MitoNEET. Taken together, our data indicate that mitoNEET regulates VDAC in a redox-dependent manner in cells, closing the pore and likely disrupting VDAC’s flow of metabolites.
17
Zhong, Zhisheng, Yanhong Hao, Rongfeng Li, Lee Spate, David Wax, Qing-Yuan Sun, Randall S. Prather, and Heide Schatten. "Analysis of Heterogeneous Mitochondria Distribution in Somatic Cell Nuclear Transfer Porcine Embryos." Microscopy and Microanalysis 14, no. 5 (September 16, 2008): 418–32. http://dx.doi.org/10.1017/s1431927608080896.
Full textAbstract:
AbstractWe previously reported that translocation of mitochondria from the oocyte cortex to the perinuclear area indicates positive developmental potential that was reduced in porcine somatic cell nuclear transfer (SCNT) embryos compared to in vitro–fertilized (IVF) embryos (Katayama, M., Zhong, Z.-S., Lai, L., Sutovsky, P., Prather, R.S. & Schatten, H. (2006). Dev Biol299, 206–220.). The present study is focused on distribution of donor cell mitochondria in intraspecies (pig oocytes; pig fetal fibroblast cells) and interspecies (pig oocytes; mouse fibroblast cells) reconstructed embryos by using either pig fibroblasts with mitochondria-stained MitoTracker CMXRos or YFP-mitochondria 3T3 cells (pPhi-Yellow-mito) as donor cells. Transmission electron microscopy was employed for ultrastructural analysis of pig oocyte and donor cell mitochondria. Our results revealed donor cell mitochondrial clusters around the donor nucleus that gradually dispersed into the ooplasm at 3 h after SCNT. Donor-derived mitochondria distributed into daughter blastomeres equally (82.8%) or unequally (17.2%) at first cleavage. Mitochondrial morphology was clearly different between donor cells and oocytes in which various complex shapes and configurations were seen. These data indicate that (1) unequal donor cell mitochondria distribution is observed in 17.2% of embryos, which may negatively influence development; and (2) complex mitochondrial morphologies are observed in IVF and SCNT embryos, which may influence mitochondrial translocation and affect development.
18
Yamada, Mitsutoshi, Kazuhiro Akashi, Reina Ooka, Kenji Miyado, and Hidenori Akutsu. "Mitochondrial Genetic Drift after Nuclear Transfer in Oocytes." International Journal of Molecular Sciences 21, no. 16 (August 16, 2020): 5880. http://dx.doi.org/10.3390/ijms21165880.
Full textAbstract:
Mitochondria are energy-producing intracellular organelles containing their own genetic material in the form of mitochondrial DNA (mtDNA), which codes for proteins and RNAs essential for mitochondrial function. Some mtDNA mutations can cause mitochondria-related diseases. Mitochondrial diseases are a heterogeneous group of inherited disorders with no cure, in which mutated mtDNA is passed from mothers to offspring via maternal egg cytoplasm. Mitochondrial replacement (MR) is a genome transfer technology in which mtDNA carrying disease-related mutations is replaced by presumably disease-free mtDNA. This therapy aims at preventing the transmission of known disease-causing mitochondria to the next generation. Here, a proof of concept for the specific removal or editing of mtDNA disease-related mutations by genome editing is introduced. Although the amount of mtDNA carryover introduced into human oocytes during nuclear transfer is low, the safety of mtDNA heteroplasmy remains a concern. This is particularly true regarding donor-recipient mtDNA mismatch (mtDNA–mtDNA), mtDNA-nuclear DNA (nDNA) mismatch caused by mixing recipient nDNA with donor mtDNA, and mtDNA replicative segregation. These conditions can lead to mtDNA genetic drift and reversion to the original genotype. In this review, we address the current state of knowledge regarding nuclear transplantation for preventing the inheritance of mitochondrial diseases.
19
Montgomery, Magdalene K. "Mitochondrial Dysfunction and Diabetes: Is Mitochondrial Transfer a Friend or Foe?" Biology 8, no. 2 (May 11, 2019): 33. http://dx.doi.org/10.3390/biology8020033.
Full textAbstract:
Obesity, insulin resistance and type 2 diabetes are accompanied by a variety of systemic and tissue-specific metabolic defects, including inflammation, oxidative and endoplasmic reticulum stress, lipotoxicity, and mitochondrial dysfunction. Over the past 30 years, association studies and genetic manipulations, as well as lifestyle and pharmacological invention studies, have reported contrasting findings on the presence or physiological importance of mitochondrial dysfunction in the context of obesity and insulin resistance. It is still unclear if targeting mitochondrial function is a feasible therapeutic approach for the treatment of insulin resistance and glucose homeostasis. Interestingly, recent studies suggest that intact mitochondria, mitochondrial DNA, or other mitochondrial factors (proteins, lipids, miRNA) are found in the circulation, and that metabolic tissues secrete exosomes containing mitochondrial cargo. While this phenomenon has been investigated primarily in the context of cancer and a variety of inflammatory states, little is known about the importance of exosomal mitochondrial transfer in obesity and diabetes. We will discuss recent evidence suggesting that (1) tissues with mitochondrial dysfunction shed their mitochondria within exosomes, and that these exosomes impair the recipient’s cell metabolic status, and that on the other hand, (2) physiologically healthy tissues can shed mitochondria to improve the metabolic status of recipient cells. In this context the determination of whether mitochondrial transfer in obesity and diabetes is a friend or foe requires further studies.
20
Straub, Sebastian P., Sebastian B. Stiller, Nils Wiedemann, and Nikolaus Pfanner. "Dynamic organization of the mitochondrial protein import machinery." Biological Chemistry 397, no. 11 (November 1, 2016): 1097–114. http://dx.doi.org/10.1515/hsz-2016-0145.
Full textAbstract:
Abstract Mitochondria contain elaborate machineries for the import of precursor proteins from the cytosol. The translocase of the outer mitochondrial membrane (TOM) performs the initial import of precursor proteins and transfers the precursors to downstream translocases, including the presequence translocase and the carrier translocase of the inner membrane, the mitochondrial import and assembly machinery of the intermembrane space, and the sorting and assembly machinery of the outer membrane. Although the protein translocases can function as separate entities in vitro, recent studies revealed a close and dynamic cooperation of the protein import machineries to facilitate efficient transfer of precursor proteins in vivo. In addition, protein translocases were found to transiently interact with distinct machineries that function in the respiratory chain or in the maintenance of mitochondrial membrane architecture. Mitochondrial protein import is embedded in a regulatory network that ensures protein biogenesis, membrane dynamics, bioenergetic activity and quality control.
21
Zhang, Chao, Li Tao, Yuan Yue, Likun Ren, Zhenni Zhang, Xiaodong Wang, Jianhui Tian, and Lei An. "Mitochondrial transfer from induced pluripotent stem cells rescues developmental potential of in vitro fertilized embryos from aging females†." Biology of Reproduction 104, no. 5 (January 28, 2021): 1114–25. http://dx.doi.org/10.1093/biolre/ioab009.
Full textAbstract:
Abstract Conventional heterologous mitochondrial replacement therapy is clinically complicated by “tri-parental” ethical concerns and limited source of healthy donor oocytes or zygotes. Autologous mitochondrial transfer is a promising alternative in rescuing poor oocyte quality and impaired embryo developmental potential associated with mitochondrial disorders, including aging. However, the efficacy and safety of mitochondrial transfer from somatic cells remains largely controversial, and unsatisfying outcomes may be due to distinct mitochondrial state in somatic cells from that in oocytes. Here, we propose a potential strategy for improving in vitro fertilization (IVF) outcomes of aging female patients via mitochondrial transfer from induced pluripotent stem (iPS) cells. Using naturally aging mice and well-established cell lines as models, we found iPS cells and oocytes share similar mitochondrial morphology and functions, whereas the mitochondrial state in differentiated somatic cells is substantially different. By microinjection of isolated mitochondria into fertilized oocytes following IVF, our results indicate that mitochondrial transfer from iPS, but not MEF cells, can rescue the impaired developmental potential of embryos from aging female mice and obtain an enhanced implantation rate following embryo transfer. The beneficial effect may be explained by the fact that mitochondrial transfer from iPS cells not only compensates for aging-associated loss of mtDNA, but also rescues mitochondrial metabolism of subsequent preimplantation embryos. Using mitochondria from iPS cells as the donor, our study not only proposes a promising strategy for improving IVF outcomes of aging females, but also highlights the importance of synchronous mitochondrial state in supporting embryo developmental potential.
22
Marlein, Christopher, Lyubov Zaitseva, Rachel E. Piddock, Stephen Robinson, Dylan R. Edwards, Manar S. Shafat, Kristian M. Bowles, and Stuart A. Rushworth. "Bone Marrow Mesenchymal Stromal Cells Transfer Their Mitochondria to Acute Myeloid Leukaemia Blasts to Support Their Proliferation and Survival." Blood 128, no. 22 (December 2, 2016): 772. http://dx.doi.org/10.1182/blood.v128.22.772.772.
Full textAbstract:
Abstract Background Survival of acute myeloid leukaemia (AML) blasts is established to be heavily dependent on the bone marrow microenvironment, where bone marrow mesenchymal stromal cells (BM-MSCs) are an important cell type. Contrary to the Warburg hypothesis, AML blasts rely on oxidative phosphorylation for survival and have increased mitochondrial levels compared to normal CD34+ progenitors. Current research is being directed at the biology behind how the bone marrow microenvironment supports the proliferation of the disease. With the knowledge that AML blasts have an increased mitochondrial mass and that BM-MSCs have the ability to be mitochondrial donors, we examined the BM-MSC AML blast interaction to determine if the increased mitochondrial mass was a result of inter-cellular mitochondrial transfer. Methods Primary AML blasts were obtained from patient bone marrow. Primary AML and normal BM-MSCs were isolated from patients bone marrow, with informed consent and under approval from the UK National Research Ethics Service (LRCEref07/H0310/146), using adherence. BM-MSCs were characterised using flow cytometry for expression of CD90+, CD73+, CD105+ and CD45-. Mitochondrial transfer was assessed in vitro using qPCR and MitoTracker staining based methods. A P0 OCI-AML3 cell line was created using a 40-day incubation with ethidium bromide, pyruvate and uridine. In vivo experiments using an NSG primary AML xenograft model were also carried out (in accordance with University of East Anglia ethics review board). For mechanistic determination, BM-MSCs with a mCherry mitochondrial labelled protein were created using a lentivirus. Levels of mitochondrial transfer were assessed by mCherry mitochondrial protein acquisition in the AML during co-culture with the BM-MSCs. Results We report that BM-MSCs support AML blast survival via the inter-cellular transfer of mitochondria from 'benign' to malignant cells. To examine this transfer we used primary AML blasts and BM-MSCs derived from patient bone marrow, along with AML cell lines. We found in vitro that primary AML blasts increase their mitochondrial mass, respiratory capacity and ATP production after co-culture with primary BM-MSCs. A P0 OCI-AML3 cell line, with mutated mitochondrial DNA (mtDNA), was generated using ethidium bromide treatment allowing mitochondrial transfer to be specifically analysed. mtDNA was restored in this cell line after co-culture with primary BM-MSCs. Further to this mouse mtDNA was detected in the P0 OCI-AML3 cells after co-culture with the mouse BM-MSC cell line (M2-10B4). Moreover, mitochondrial transfer was directly observed between primary BM-MSCs and primary AML blasts, visualised by the acquisition of a mCherry labelled mitochondrial protein. This transfer of mitochondria was one directional. Moreover, a reduction of mitochondrial transfer was observed in AML blasts upon the addition of cytochalasin to the co-culture, highlighting that mitochondrial transfer is at least in part facilitated through tunnelling nanotubes (TNTs). Finally, mitochondrial transfer was confirmed in vivo whereby murine mitochondria were transferred to human AML in a mouse xenografts model. Conclusion Here we show that the bone marrow microenvironment supports the AML blasts by donating mitochondria, which in turn enhances the oxidative phosphorylation and growth capacity of the blasts. Targeting the microenvironment is predicted to provide novel therapeutic approaches for the treatment of cancer. Disclosures Rushworth: Infinity Pharmaceuticals: Research Funding.
23
Kuo, Ivana Y., Allison L. Brill, Fernanda O. Lemos, Jason Y. Jiang, Jeffrey L. Falcone, Erica P. Kimmerling, Yiqiang Cai, et al. "Polycystin 2 regulates mitochondrial Ca2+ signaling, bioenergetics, and dynamics through mitofusin 2." Science Signaling 12, no. 580 (May 7, 2019): eaat7397. http://dx.doi.org/10.1126/scisignal.aat7397.
Full textAbstract:
Mitochondria and the endoplasmic reticulum (ER) have an intimate functional relationship due to tethering proteins that bring their membranes in close (~30 nm) apposition. One function of this interorganellar junction is to increase the efficiency of Ca2+ transfer into mitochondria, thus stimulating mitochondrial respiration. Here, we showed that the ER cation-permeant channel polycystin 2 (PC2) functions to reduce mitochondria-ER contacts. In cell culture models, PC2 knockdown led to a 50% increase in mitofusin 2 (MFN2) expression, an outer mitochondrial membrane GTPase. Live-cell super-resolution and electron microscopy analyses revealed enhanced MFN2-dependent tethering between the ER and mitochondria in PC2 knockdown cells. PC2 knockdown also led to increased ER-mediated mitochondrial Ca2+ signaling, bioenergetic activation, and mitochondrial density. Mutation or deletion of the gene encoding for PC2 results in autosomal dominant polycystic kidney disease (ADPKD), a condition characterized by numerous fluid-filled cysts. In cell culture models and mice with kidney-specific PC2 knockout, knockdown of MFN2 rescued defective mitochondrial Ca2+ transfer and diminished cell proliferation in kidney cysts. Consistent with these results, cyst-lining epithelial cells from human ADPKD kidneys had a twofold increase in mitochondria and MFN2 expression. Our data suggest that PC2 normally serves to limit key mitochondrial proteins at the ER-mitochondrial interface and acts as a checkpoint for mitochondrial biogenesis and bioenergetics. Loss of this regulation may contribute to the increased oxidative metabolism and aberrant cell proliferation typical of kidney cysts in ADPKD.
24
Krols, Michiel, Geert Bultynck, and Sophie Janssens. "ER–Mitochondria contact sites: A new regulator of cellular calcium flux comes into play." Journal of Cell Biology 214, no. 4 (August 15, 2016): 367–70. http://dx.doi.org/10.1083/jcb.201607124.
Full textAbstract:
Endoplasmic reticulum (ER)–mitochondria membrane contacts are hotspots for calcium signaling. In this issue, Raturi et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201512077) show that the thioredoxin TMX1 inhibits the calcium pump SERCA2b at ER–mitochondria contact sites, thereby affecting ER–mitochondrial calcium transfer and mitochondrial bioenergetics.
25
Mistry, Jayna J., Christopher R. Marlein, Jamie A. Moore, Charlotte Hellmich, Edyta E. Wojtowicz, James G. W. Smith, Iain Macaulay, et al. "ROS-mediated PI3K activation drives mitochondrial transfer from stromal cells to hematopoietic stem cells in response to infection." Proceedings of the National Academy of Sciences 116, no. 49 (November 14, 2019): 24610–19. http://dx.doi.org/10.1073/pnas.1913278116.
Full textAbstract:
Hematopoietic stem cells (HSCs) undergo rapid expansion in response to stress stimuli. Here we investigate the bioenergetic processes which facilitate the HSC expansion in response to infection. We find that infection by Gram-negative bacteria drives an increase in mitochondrial mass in mammalian HSCs, which results in a metabolic transition from glycolysis toward oxidative phosphorylation. The initial increase in mitochondrial mass occurs as a result of mitochondrial transfer from the bone marrow stromal cells (BMSCs) to HSCs through a reactive oxygen species (ROS)-dependent mechanism. Mechanistically, ROS-induced oxidative stress regulates the opening of connexin channels in a system mediated by phosphoinositide 3-kinase (PI3K) activation, which allows the mitochondria to transfer from BMSCs into HSCs. Moreover, mitochondria transfer from BMSCs into HSCs, in the response to bacterial infection, occurs before the HSCs activate their own transcriptional program for mitochondrial biogenesis. Our discovery demonstrates that mitochondrial transfer from the bone marrow microenvironment to HSCs is an early physiologic event in the mammalian response to acute bacterial infection and results in bioenergetic changes which underpin emergency granulopoiesis.
26
Rimessi, Alessandro, Chiara Pozzato, Lorenzo Carparelli, Alice Rossi, Serena Ranucci, Ida De Fino, Cristina Cigana, et al. "Pharmacological modulation of mitochondrial calcium uniporter controls lung inflammation in cystic fibrosis." Science Advances 6, no. 19 (May 2020): eaax9093. http://dx.doi.org/10.1126/sciadv.aax9093.
Full textAbstract:
Mitochondria physically associate with the endoplasmic reticulum to coordinate interorganelle calcium transfer and regulate fundamental cellular processes, including inflammation. Deregulated endoplasmic reticulum–mitochondria cross-talk can occur in cystic fibrosis, contributing to hyperinflammation and disease progression. We demonstrate that Pseudomonas aeruginosa infection increases endoplasmic reticulum–mitochondria associations in cystic fibrosis bronchial cells by stabilizing VAPB-PTPIP51 (vesicle-associated membrane protein–associated protein B–protein tyrosine phosphatase interacting protein 51) tethers, affecting autophagy. Impaired autophagy induced mitochondrial unfolding protein response and NLRP3 inflammasome activation, contributing to hyperinflammation. The mechanism by which VAPB-PTPIP51 tethers regulate autophagy in cystic fibrosis involves calcium transfer via mitochondrial calcium uniporter. Mitochondrial calcium uniporter inhibition rectified autophagy and alleviated the inflammatory response in vitro and in vivo, resulting in a valid therapeutic strategy for cystic fibrosis pulmonary disease.
27
Han, Deqiang, Xin Zheng, Xueyao Wang, Tao Jin, Li Cui, and Zhiguo Chen. "Mesenchymal Stem/Stromal Cell-Mediated Mitochondrial Transfer and the Therapeutic Potential in Treatment of Neurological Diseases." Stem Cells International 2020 (July 7, 2020): 1–16. http://dx.doi.org/10.1155/2020/8838046.
Full textAbstract:
Mesenchymal stem/stromal cells (MSCs) are multipotent stem cells that can be derived from various tissues. Due to their regenerative and immunomodulatory properties, MSCs have been extensively researched and tested for treatment of different diseases/indications. One mechanism that MSCs exert functions is through the transfer of mitochondria, a key player involved in many biological processes in health and disease. Mitochondria transfer is bidirectional and has an impact on both donor and recipient cells. In this review, we discussed how MSC-mediated mitochondrial transfer may affect cellular metabolism, survival, proliferation, and differentiation; how this process influences inflammatory processes; and what is the molecular machinery that mediates mitochondrial transfer. In the end, we summarized recent advances in preclinical research and clinical trials for the treatment of stroke and spinal cord injury, through application of MSCs and/or MSC-derived mitochondria.
28
Koch, Christian, Maya Schuldiner, and Johannes M. Herrmann. "ER-SURF: Riding the Endoplasmic Reticulum Surface to Mitochondria." International Journal of Molecular Sciences 22, no. 17 (September 6, 2021): 9655. http://dx.doi.org/10.3390/ijms22179655.
Full textAbstract:
Most mitochondrial proteins are synthesized in the cytosol and targeted to the mitochondrial surface in a post-translational manner. The surface of the endoplasmic reticulum (ER) plays an active role in this targeting reaction. ER-associated chaperones interact with certain mitochondrial membrane protein precursors and transfer them onto receptor proteins of the mitochondrial surface in a process termed ER-SURF. ATP-driven proteins in the membranes of mitochondria (Msp1, ATAD1) and the ER (Spf1, P5A-ATPase) serve as extractors for the removal of mislocalized proteins. If the re-routing to mitochondria fails, precursors can be degraded by ER or mitochondria-associated degradation (ERAD or MAD respectively) in a proteasome-mediated reaction. This review summarizes the current knowledge about the cooperation of the ER and mitochondria in the targeting and quality control of mitochondrial precursor proteins.
29
Nagashima, Shun, Keisuke Takeda, Nobuhiko Ohno, Satoshi Ishido, Motohide Aoki, Yurika Saitoh, Takumi Takada, et al. "MITOL deletion in the brain impairs mitochondrial structure and ER tethering leading to oxidative stress." Life Science Alliance 2, no. 4 (August 2019): e201900308. http://dx.doi.org/10.26508/lsa.201900308.
Full textAbstract:
Mitochondrial abnormalities are associated with developmental disorders, although a causal relationship remains largely unknown. Here, we report that increased oxidative stress in neurons by deletion of mitochondrial ubiquitin ligase MITOL causes a potential neuroinflammation including aberrant astrogliosis and microglial activation, indicating that mitochondrial abnormalities might confer a risk for inflammatory diseases in brain such as psychiatric disorders. A role of MITOL in both mitochondrial dynamics and ER-mitochondria tethering prompted us to characterize three-dimensional structures of mitochondria in vivo. In MITOL-deficient neurons, we observed a significant reduction in the ER-mitochondria contact sites, which might lead to perturbation of phospholipids transfer, consequently reduce cardiolipin biogenesis. We also found that branched large mitochondria disappeared by deletion of MITOL. These morphological abnormalities of mitochondria resulted in enhanced oxidative stress in brain, which led to astrogliosis and microglial activation partly causing abnormal behavior. In conclusion, the reduced ER-mitochondria tethering and excessive mitochondrial fission may trigger neuroinflammation through oxidative stress.
30
Li, Chia-Jung, Po-Kong Chen, Li-Yi Sun, and Cheng-Yoong Pang. "Enhancement of Mitochondrial Transfer by Antioxidants in Human Mesenchymal Stem Cells." Oxidative Medicine and Cellular Longevity 2017 (2017): 1–13. http://dx.doi.org/10.1155/2017/8510805.
Full textAbstract:
Excessive reactive oxygen species is the major component of a harsh microenvironment after ischemia/reperfusion injury in human tissues. Combined treatment of N-acetyl-L-cysteine (NAC) and L-ascorbic acid 2-phosphate (AAP) promoted the growth of human mesenchymal stem cells (hMSCs) and suppressed oxidative stress-induced cell death by enhancing mitochondrial integrity and function in vitro. In this study, we aimed to determine whether NAC and AAP (termed MCA) could enhance the therapeutic potential of hMSCs. We established a coculture system consisting of MCA-treated and H2O2-treated hMSCs and investigated the role of tunneling nanotubes (TNTs) in the exchange of mitochondria between the 2 cell populations. The consequences of mitochondria exchange were assessed by fluorescence confocal microscopy and flow cytometry. The results showed that MCA could increase the mitochondrial mass, respiratory capacity, and numbers of TNTs in hMSCs. The “energized” mitochondria were transferred to the injured hMSCs via TNTs, the oxidative stress was decreased, and the mitochondrial membrane potential of the H2O2-treated hMSCs was stabilized. The transfer of mitochondria decreased the expression of S616-phosphorylated dynamin-related protein 1, a protein that dictates the fragmentation/fission of mitochondria. Concurrently, MCA also enhanced mitophagy in the coculture system, implicating that damaged mitochondria were eliminated in order to maintain cell physiology.
31
Tai, Suzanna. "Mitochondrial replacement therapy and the “three parent baby”." SURG Journal 9, no. 1 (April 9, 2017): 48–56. http://dx.doi.org/10.21083/surg.v9i1.3800.
Full textAbstract:
The mitochondria contained in eukaryotic cells have their own DNA, and heritable mutations in mitochondrial DNA (mtDNA) can cause a variety of disorders in humans. A new therapy, mitochondrial replacement therapy (MRT), is currently being developed to address these mitochondrial disorders by eliminating the mutated mtDNA from the germline. The two main MRT techniques are pronuclear transfer, conducted in the zygote after fertilization, and spindle-chromosomal complex transfer, conducted in the oocyte before fertilization. In pronuclear transfer, the pronuclei from a zygote affected by a mtDNA mutation are transferred to an enucleated normal zygote. In spindle-chromosomal complex transfer, the genetic material from an oocyte affected by a mtDNA mutation is inserted into the cytoplasm of a donor oocyte that contains healthy mitochondria. A third method, polar body genome transfer, attempts to increase the efficiency of the above techniques by using polar bodies to supply the genetic material. While MRT is legally and ethically controversial, it has recently been implemented successfully in a clinical setting.
32
Schwer, Björn, Shaotang Ren, Thomas Pietschmann, Jürgen Kartenbeck, Katrin Kaehlcke, Ralf Bartenschlager, T. S. Benedict Yen, and Melanie Ott. "Targeting of Hepatitis C Virus Core Protein to Mitochondria through a Novel C-Terminal Localization Motif." Journal of Virology 78, no. 15 (August 1, 2004): 7958–68. http://dx.doi.org/10.1128/jvi.78.15.7958-7968.2004.
Full textAbstract:
ABSTRACT The hepatitis C virus (HCV) core protein represents the first 191 amino acids of the viral precursor polyprotein and is cotranslationally inserted into the membrane of the endoplasmic reticulum (ER). Processing at position 179 by a recently identified intramembrane signal peptide peptidase leads to the generation and potential cytosolic release of a 179-amino-acid matured form of the core protein. Using confocal microscopy, we observed that a fraction of the mature core protein colocalized with mitochondrial markers in core-expressing HeLa cells and in Huh-7 cells containing the full-length HCV replicon. Subcellular fractionation confirmed this observation and showed that the core protein associates with purified mitochondrial fractions devoid of ER contaminants. The core protein also fractionated with mitochondrion-associated membranes, a site of physical contact between the ER and mitochondria. Using immunoelectron microscopy and in vitro mitochondrial import assays, we showed that the core protein is located on the mitochondrial outer membrane. A stretch of 10 amino acids within the hydrophobic C terminus of the processed core protein conferred mitochondrial localization when it was fused to green fluorescent protein. The location of the core protein in the outer mitochondrial membrane suggests that it could modulate apoptosis or lipid transfer, both of which are associated with this subcellular compartment, during HCV infection.
33
Kami, Daisuke, and Satoshi Gojo. "From Cell Entry to Engraftment of Exogenous Mitochondria." International Journal of Molecular Sciences 21, no. 14 (July 15, 2020): 4995. http://dx.doi.org/10.3390/ijms21144995.
Full textAbstract:
Mitochondrial transfer has been recognized to play a role in a variety of processes, ranging from fertilization to cancer and neurodegenerative diseases as well as mammalian horizontal gene transfer. It is achieved through either exogeneous or intercellular mitochondrial transfer. From the viewpoint of evolution, exogeneous mitochondrial transfer is quite akin to the initial process of symbiosis between α-protobacterium and archaea, although the progeny have developed more sophisticated machinery to engulf environmental materials, including nutrients, bacteria, and viruses. A molecular-based knowledge of endocytosis, including macropinocytosis and endosomal escape involving bacteria and viruses, could provide mechanistic insights into exogeneous mitochondrial transfer. We focus on exogeneous mitochondrial transfer in this review to facilitate the clinical development of the use of isolated mitochondria to treat various pathological conditions. Several kinds of novel procedures to enhance exogeneous mitochondrial transfer have been developed and are summarized in this review.
34
Delprat, Benjamin, Jennifer Rieusset, and Cécile Delettre. "Defective Endoplasmic Reticulum–Mitochondria Connection Is a Hallmark of Wolfram Syndrome." Contact 2 (January 2019): 251525641984740. http://dx.doi.org/10.1177/2515256419847407.
Full textAbstract:
Interactions between endoplasmic reticulum (ER) and mitochondria are key components of essential cellular functions. Indeed, these membrane appositions are necessary for proper Ca2+ transfer from ER to mitochondria, to regulate lipid metabolism, apoptosis, and inflammation. We report that the ER protein WFS1 interacts with the neuronal calcium sensor protein NCS1 to regulate mitochondria associated-ER membrane formation. Mutations in the WFS1 gene are associated with Wolfram syndrome, a rare neurodegenerative disease. We demonstrated that human WFS1-deficient cells lack NCS1 and fail to tether ER and mitochondria, resulting in a decrease in Ca2+ transfer and mitochondrial respiration. Interestingly, we showed that NCS1 overexpression in WFS1-deficient cells restored ER–mitochondria interactions and calcium exchange. Our results suggest that WFS1 regulates ER tethering to mitochondria through NCS1 and that restoration of NCS1 expression could be a therapeutic tool for restoring calcium signaling at the mitochondria associated-ER membrane interface and mitochondrial function in Wolfram syndrome.
35
Hynes, Michael J., Sandra L. Murray, Alex Andrianopoulos, and Meryl A. Davis. "Role of Carnitine Acetyltransferases in Acetyl Coenzyme A Metabolism in Aspergillus nidulans." Eukaryotic Cell 10, no. 4 (February 4, 2011): 547–55. http://dx.doi.org/10.1128/ec.00295-10.
Full textAbstract:
ABSTRACTThe flow of carbon metabolites between cellular compartments is an essential feature of fungal metabolism. During growth on ethanol, acetate, or fatty acids, acetyl units must enter the mitochondrion for metabolism via the tricarboxylic acid cycle, and acetyl coenzyme A (acetyl-CoA) in the cytoplasm is essential for the biosynthetic reactions and for protein acetylation. Acetyl-CoA is produced in the cytoplasm by acetyl-CoA synthetase during growth on acetate and ethanol while β-oxidation of fatty acids generates acetyl-CoA in peroxisomes. The acetyl-carnitine shuttle in which acetyl-CoA is reversibly converted to acetyl-carnitine by carnitine acetyltransferase (CAT) enzymes is important for intracellular transport of acetyl units. In the filamentous ascomyceteAspergillus nidulans, a cytoplasmic CAT, encoded byfacC, is essential for growth on sources of cytoplasmic acetyl-CoA while a second CAT, encoded by theacuJgene, is essential for growth on fatty acids as well as acetate. We have shown that AcuJ contains an N-terminal mitochondrial targeting sequence and a C-terminal peroxisomal targeting sequence (PTS) and is localized to both peroxisomes and mitochondria, independent of the carbon source. Mislocalization of AcuJ to the cytoplasm does not result in loss of growth on acetate but prevents growth on fatty acids. Therefore, while mitochondrial AcuJ is essential for the transfer of acetyl units to mitochondria, peroxisomal localization is required only for transfer from peroxisomes to mitochondria. Peroxisomal AcuJ was not required for the import of acetyl-CoA into peroxisomes for conversion to malate by malate synthase (MLS), and export of acetyl-CoA from peroxisomes to the cytoplasm was found to be independent of FacC when MLS was mislocalized to the cytoplasm.
36
Ouyang, Yi-Bing, and Rona G. Giffard. "ER-Mitochondria Crosstalk during Cerebral Ischemia: Molecular Chaperones and ER-Mitochondrial Calcium Transfer." International Journal of Cell Biology 2012 (2012): 1–8. http://dx.doi.org/10.1155/2012/493934.
Full textAbstract:
It is commonly believed that sustained elevations in the mitochondrial matrix Ca2+concentration are a major feature of the intracellular cascade of lethal events during cerebral ischemia. The physical association between the endoplasmic reticulum (ER) and mitochondria, known as the mitochondria-associated ER membrane (MAM), enables highly efficient transmission of Ca2+from the ER to mitochondria under both physiological and pathological conditions. Molecular chaperones are well known for their protective effects during cerebral ischemia. It has been demonstrated recently that many molecular chaperones coexist with MAM and regulate the MAM and thus Ca2+concentration inside mitochondria. Here, we review recent research on cerebral ischemia and MAM, with a focus on molecular chaperones and ER-mitochondrial calcium transfer.
37
Milner, David S., Jeremy G. Wideman, Courtney W. Stairs, Cory D. Dunn, and Thomas A. Richards. "A functional bacteria-derived restriction modification system in the mitochondrion of a heterotrophic protist." PLOS Biology 19, no. 4 (April 23, 2021): e3001126. http://dx.doi.org/10.1371/journal.pbio.3001126.
Full textAbstract:
The overarching trend in mitochondrial genome evolution is functional streamlining coupled with gene loss. Therefore, gene acquisition by mitochondria is considered to be exceedingly rare. Selfish elements in the form of self-splicing introns occur in many organellar genomes, but the wider diversity of selfish elements, and how they persist in the DNA of organelles, has not been explored. In the mitochondrial genome of a marine heterotrophic katablepharid protist, we identify a functional type II restriction modification (RM) system originating from a horizontal gene transfer (HGT) event involving bacteria related to flavobacteria. This RM system consists of an HpaII-like endonuclease and a cognate cytosine methyltransferase (CM). We demonstrate that these proteins are functional by heterologous expression in both bacterial and eukaryotic cells. These results suggest that a mitochondrion-encoded RM system can function as a toxin–antitoxin selfish element, and that such elements could be co-opted by eukaryotic genomes to drive biased organellar inheritance.
38
Golan, Karin, Abhishek K. Singh, Orit Kollet, Mayla Bertagna, Mark J. Althoff, Eman Khatib-Massalha, Ekaterina Petrovich-Kopitman, et al. "Bone marrow regeneration requires mitochondrial transfer from donor Cx43-expressing hematopoietic progenitors to stroma." Blood 136, no. 23 (December 3, 2020): 2607–19. http://dx.doi.org/10.1182/blood.2020005399.
Full textAbstract:
Abstract The fate of hematopoietic stem and progenitor cells (HSPC) is tightly regulated by their bone marrow (BM) microenvironment (ME). BM transplantation (BMT) frequently requires irradiation preconditioning to ablate endogenous hematopoietic cells. Whether the stromal ME is damaged and how it recovers after irradiation is unknown. We report that BM mesenchymal stromal cells (MSC) undergo massive damage to their mitochondrial function after irradiation. Donor healthy HSPC transfer functional mitochondria to the stromal ME, thus improving mitochondria activity in recipient MSC. Mitochondrial transfer to MSC is cell-contact dependent and mediated by HSPC connexin-43 (Cx43). Hematopoietic Cx43-deficient chimeric mice show reduced mitochondria transfer, which was rescued upon re-expression of Cx43 in HSPC or culture with isolated mitochondria from Cx43 deficient HSPCs. Increased intracellular adenosine triphosphate levels activate the purinergic receptor P2RX7 and lead to reduced activity of adenosine 5′-monophosphate–activated protein kinase (AMPK) in HSPC, dramatically increasing mitochondria transfer to BM MSC. Host stromal ME recovery and donor HSPC engraftment were augmented after mitochondria transfer. Deficiency of Cx43 delayed mesenchymal and osteogenic regeneration while in vivo AMPK inhibition increased stromal recovery. As a consequence, the hematopoietic compartment reconstitution was improved because of the recovery of the supportive stromal ME. Our findings demonstrate that healthy donor HSPC not only reconstitute the hematopoietic system after transplantation, but also support and induce the metabolic recovery of their irradiated, damaged ME via mitochondria transfer. Understanding the mechanisms regulating stromal recovery after myeloablative stress are of high clinical interest to optimize BMT procedures and underscore the importance of accessory, non-HSC to accelerate hematopoietic engraftment.
39
Cortese, J. D., A. L. Voglino, and C. R. Hackenbrock. "Ionic strength of the intermembrane space of intact mitochondria as estimated with fluorescein-BSA delivered by low pH fusion." Journal of Cell Biology 113, no. 6 (June 15, 1991): 1331–40. http://dx.doi.org/10.1083/jcb.113.6.1331.
Full textAbstract:
The electrostatic interactions of cytochrome c with its redox partners and membrane lipids, as well as other protein interactions and biochemical reactions, may be modulated by the ionic strength of the intermembrane space of the mitochondrion. FITC-BSA was used to determine the relative value of the mitochondrial intermembrane ionic strength with respect to bulk medium external to the mitochondrial outer membrane. FITC-BSA exhibited an ionic strength-dependent fluorescence change with an affinity in the mM range as opposed to its pH sensitivity in the microM range. A controlled, low pH-induced membrane fusion procedure was developed to transfer FITC-BSA encapsulated in asolectin liposomes, to the intermembrane space of intact mitochondria. The fusion procedure did not significantly affect mitochondrial ultrastructure, electron transport, or respiratory control ratios. The extent of fusion of liposomes with the mitochondrial outer membrane was monitored by fluorescence dequenching assays using a membrane fluorescent probe (octadecylrhodamine B) and the soluble FITC-BSA fluorescent probe, which report membrane and contents mixing, respectively. Assays were consistent with a rapid, low pH-induced vesicle-outer membrane fusion and delivery of FITC-BSA into the intermembrane space. Similar affinities for the ionic strength-dependent change in fluorescence were found for bulk medium, soluble (9.8 +/- 0.8 mM) and intermembrane space-entrapped FITC-BSA (10.2 +/- 0.6 mM). FITC-BSA consistently reported an ionic strength in the intermembrane space of the functionally and structurally intact mitochondria within +/- 20% of the external bulk solution. These findings reveal that the intermembrane ionic strength changes as does the external ionic strength and suggest that cytochrome c interactions, as well as other protein interactions and biochemical reactions, proceed in the intermembrane space of mitochondria in the intact cell at physiological ionic strength, i.e., 100-150 mM.
40
Endo, Toshiya, and Haruka Sakaue. "Multifaceted roles of porin in mitochondrial protein and lipid transport." Biochemical Society Transactions 47, no. 5 (October 31, 2019): 1269–77. http://dx.doi.org/10.1042/bst20190153.
Full textAbstract:
Abstract Mitochondria are essential eukaryotic organelles responsible for primary cellular energy production. Biogenesis, maintenance, and functions of mitochondria require correct assembly of resident proteins and lipids, which require their transport into and within mitochondria. Mitochondrial normal functions also require an exchange of small metabolites between the cytosol and mitochondria, which is primarily mediated by a metabolite channel of the outer membrane (OM) called porin or voltage-dependent anion channel. Here, we describe recently revealed novel roles of porin in the mitochondrial protein and lipid transport. First, porin regulates the formation of the mitochondrial protein import gate in the OM, the translocase of the outer membrane (TOM) complex, and its dynamic exchange between the major form of a trimer and the minor form of a dimer. The TOM complex dimer lacks a core subunit Tom22 and mediates the import of a subset of mitochondrial proteins while the TOM complex trimer facilitates the import of most other mitochondrial proteins. Second, porin interacts with both a translocating inner membrane (IM) protein like a carrier protein accumulated at the small TIM chaperones in the intermembrane space and the TIM22 complex, a downstream translocator in the IM for the carrier protein import. Porin thereby facilitates the efficient transfer of carrier proteins to the IM during their import. Third, porin facilitates the transfer of lipids between the OM and IM and promotes a back-up pathway for the cardiolipin synthesis in mitochondria. Thus, porin has roles more than the metabolite transport in the protein and lipid transport into and within mitochondria, which is likely conserved from yeast to human.
41
Farooq, Jeffrey, You Jeong Park, Justin Cho, Madeline Saft, Nadia Sadanandan, Blaise Cozene, and Cesar V. Borlongan. "Stem Cells as Drug-like Biologics for Mitochondrial Repair in Stroke." Pharmaceutics 12, no. 7 (July 1, 2020): 615. http://dx.doi.org/10.3390/pharmaceutics12070615.
Full textAbstract:
Stroke is a devastating condition characterized by widespread cell death after disruption of blood flow to the brain. The poor regenerative capacity of neural cells limits substantial recovery and prolongs disruptive sequelae. Current therapeutic options are limited and do not adequately address the underlying mitochondrial dysfunction caused by the stroke. These same mitochondrial impairments that result from acute cerebral ischemia are also present in retinal ischemia. In both cases, sufficient mitochondrial activity is necessary for cell survival, and while astrocytes are able to transfer mitochondria to damaged tissues to rescue them, they do not have the capacity to completely repair damaged tissues. Therefore, it is essential to investigate this mitochondrial transfer pathway as a target of future therapeutic strategies. In this review, we examine the current literature pertinent to mitochondrial repair in stroke, with an emphasis on stem cells as a source of healthy mitochondria. Stem cells are a compelling cell type to study in this context, as their ability to mitigate stroke-induced damage through non-mitochondrial mechanisms is well established. Thus, we will focus on the latest preclinical research relevant to mitochondria-based mechanisms in the treatment of cerebral and retinal ischemia and consider which stem cells are ideally suited for this purpose.
42
Lazzarino, D. A., I. Boldogh, M. G. Smith, J. Rosand, and L. A. Pon. "Yeast mitochondria contain ATP-sensitive, reversible actin-binding activity." Molecular Biology of the Cell 5, no. 7 (July 1994): 807–18. http://dx.doi.org/10.1091/mbc.5.7.807.
Full textAbstract:
Sedimentation assays were used to demonstrate and characterize binding of isolated yeast mitochondria to phalloidin-stabilized yeast F-actin. These actin-mitochondrial interactions are ATP sensitive, saturable, reversible, and do not depend upon mitochondrial membrane potential. Protease digestion of mitochondrial outer membrane proteins or saturation of myosin-binding sites on F-actin with the S1 subfragment of skeletal myosin block binding. These observations indicate that a protein (or proteins) on the mitochondrial surface mediates ATP-sensitive, reversible binding of mitochondria to the lateral surface of microfilaments. Actin copurifies with mitochondria during subcellular fractionation and is released from the organelle upon treatment with ATP. Thus, actin-mitochondrial interactions resembling those observed in vitro may also exist in intact yeast cells. Finally, a yeast mutant bearing a temperature-sensitive mutation in the actin-encoding ACT1 gene (act1-3) displays temperature-dependent defects in transfer of mitochondria from mother cells to newly developed buds during yeast cell mitosis.
43
Wang, Li, Qiang Wu, Zhijia Fan, Rufeng Xie, Zhicheng Wang, and Yuan Lu. "Platelet mitochondrial dysfunction and the correlation with human diseases." Biochemical Society Transactions 45, no. 6 (October 20, 2017): 1213–23. http://dx.doi.org/10.1042/bst20170291.
Full textAbstract:
The platelet is considered as an accessible and valuable tool to study mitochondrial function, owing to its greater content of fully functional mitochondria compared with other metabolically active organelles. Different lines of studies have demonstrated that mitochondria in platelets have function far more than thrombogenesis regulation, and beyond hemostasis, platelet mitochondrial dysfunction has also been used for studying mitochondrial-related diseases. In this review, the interplay between platelet mitochondrial dysfunction and oxidative stress, mitochondrial DNA lesions, electron transfer chain impairments, mitochondrial apoptosis and mitophagy has been outlined. Meanwhile, considerable efforts have been made towards understanding the role of platelet mitochondrial dysfunction in human diseases, such as diabetes mellitus, sepsis and neurodegenerative disorders. Alongside this, we have also articulated our perspectives on the development of potential biomarkers of platelet mitochondrial dysfunction in mitochondrial-related diseases.
44
Borlongan, Cesar V., Hung Nguyen, Trenton Lippert, Eleonora Russo, Julian Tuazon, Kaya Xu, Jea-Young Lee, Paul R. Sanberg, Yuji Kaneko, and Eleonora Napoli. "May the force be with you: Transfer of healthy mitochondria from stem cells to stroke cells." Journal of Cerebral Blood Flow & Metabolism 39, no. 2 (October 30, 2018): 367–70. http://dx.doi.org/10.1177/0271678x18811277.
Full textAbstract:
Stroke is a major cause of death and disability in the United States and around the world with limited therapeutic option. Here, we discuss the critical role of mitochondria in stem cell-mediated rescue of stroke brain by highlighting the concept that deleting the mitochondria from stem cells abolishes the cells’ regenerative potency. The application of innovative approaches entailing generation of mitochondria-voided stem cells as well as pharmacological inhibition of mitochondrial function may elucidate the mechanism underlying transfer of healthy mitochondria to ischemic cells, thereby providing key insights in the pathology and treatment of stroke and other brain disorders plagued with mitochondrial dysfunctions.
45
Schumacker, Paul T., Mark N. Gillespie, Kiichi Nakahira, Augustine M. K. Choi, Elliott D. Crouser, Claude A. Piantadosi, and Jahar Bhattacharya. "Mitochondria in lung biology and pathology: more than just a powerhouse." American Journal of Physiology-Lung Cellular and Molecular Physiology 306, no. 11 (June 1, 2014): L962—L974. http://dx.doi.org/10.1152/ajplung.00073.2014.
Full textAbstract:
An explosion of new information about mitochondria reveals that their importance extends well beyond their time-honored function as the “powerhouse of the cell.” In this Perspectives article, we summarize new evidence showing that mitochondria are at the center of a reactive oxygen species (ROS)-dependent pathway governing the response to hypoxia and to mitochondrial quality control. The potential role of the mitochondrial genome as a sentinel molecule governing cytotoxic responses of lung cells to ROS stress also is highlighted. Additional attention is devoted to the fate of damaged mitochondrial DNA relative to its involvement as a damage-associated molecular pattern driving adverse lung and systemic cell responses in severe illness or trauma. Finally, emerging strategies for replenishing normal populations of mitochondria after damage, either through promotion of mitochondrial biogenesis or via mitochondrial transfer, are discussed.
46
McConnell, S. J., L. C. Stewart, A. Talin, and M. P. Yaffe. "Temperature-sensitive yeast mutants defective in mitochondrial inheritance." Journal of Cell Biology 111, no. 3 (September 1, 1990): 967–76. http://dx.doi.org/10.1083/jcb.111.3.967.
Full textAbstract:
The distribution of mitochondria to daughter cells is an essential feature of mitotic cell growth, yet the molecular mechanisms facilitating this mitochondrial inheritance are unknown. We have isolated mutants of Saccharomyces cerevisiae that are temperature-sensitive for the transfer of mitochondria into a growing bud. Two of these mutants contain single, recessive, nuclear mutations, mdm1 and mdm2, that cause temperature-sensitive growth and aberrant mitochondrial distribution at the nonpermissive temperature. The absence of mitochondria from the buds of mutant cells was confirmed by indirect immunofluorescence microscopy and by transmission electron microscopy. The mdm1 lesion also retards nuclear division and prevents the transfer of nuclei into the buds. Cells containing the mdm2 mutation grown at the nonpermissive temperature sequentially form multiple buds, each receiving a nucleus but no mitochondria. Neither mdm1 or mdm2 affects the transfer of vacuolar material into the buds or causes apparent changes in the tubulin- or actin-based cytoskeletons. The mdm1 and mdm2 mutations are cell-cycle specific, displaying an execution point in late G1 or early S phase.
47
Picca, Anna, Riccardo Calvani, Hélio José Coelho-Junior, Francesco Landi, Roberto Bernabei, and Emanuele Marzetti. "Inter-Organelle Membrane Contact Sites and Mitochondrial Quality Control during Aging: A Geroscience View." Cells 9, no. 3 (March 3, 2020): 598. http://dx.doi.org/10.3390/cells9030598.
Full textAbstract:
Mitochondrial dysfunction and failing mitochondrial quality control (MQC) are major determinants of aging. Far from being standalone organelles, mitochondria are intricately related with cellular other compartments, including lysosomes. The intimate relationship between mitochondria and lysosomes is reflected by the fact that lysosomal degradation of dysfunctional mitochondria is the final step of mitophagy. Inter-organelle membrane contact sites also allow bidirectional communication between mitochondria and lysosomes as part of nondegradative pathways. This interaction establishes a functional unit that regulates metabolic signaling, mitochondrial dynamics, and, hence, MQC. Contacts of mitochondria with the endoplasmic reticulum (ER) have also been described. ER-mitochondrial interactions are relevant to Ca2+ homeostasis, transfer of phospholipid precursors to mitochondria, and integration of apoptotic signaling. Many proteins involved in mitochondrial contact sites with other organelles also participate to degradative MQC pathways. Hence, a comprehensive assessment of mitochondrial dysfunction during aging requires a thorough evaluation of degradative and nondegradative inter-organelle pathways. Here, we present a geroscience overview on (1) degradative MQC pathways, (2) nondegradative processes involving inter-organelle tethering, (3) age-related changes in inter-organelle degradative and nondegradative pathways, and (4) relevance of MQC failure to inflammaging and age-related conditions, with a focus on Parkinson’s disease as a prototypical geroscience condition.
48
Sayen, M. R., Åsa B. Gustafsson, Mark A. Sussman, Jeffery D. Molkentin, and Roberta A. Gottlieb. "Calcineurin transgenic mice have mitochondrial dysfunction and elevated superoxide production." American Journal of Physiology-Cell Physiology 284, no. 2 (February 1, 2003): C562—C570. http://dx.doi.org/10.1152/ajpcell.00336.2002.
Full textAbstract:
Introduction of the constitutively active calcineurin gene into neonatal rat cardiomyocytes by adenovirus resulted in decreased mitochondrial membrane potential ( P < 0.05). Infection of H9c2 cells with calcineurin adenovirus resulted in increased superoxide production ( P < 0.001). Transgenic mice with cardiac-specific expression of a constitutively active calcineurin cDNA (CalTG mice) exhibit a two- to threefold increase in heart size that progresses to heart failure. We prepared mitochondria enriched for the subsarcolemmal population from the hearts of CalTG mice and transgene negative littermates (control). Intact, well-coupled mitochondria prepared from one to two mouse hearts at a time yielded sufficient material for functional studies. Mitochondrial oxygen consumption was measured with a Clark-type oxygen electrode with substrates for mitochondrial complex II (succinate) and complex IV [tetramethylpentadecane (TMPD)/ascorbate]. CalTG mice exhibited a maximal rate of electron transfer in heart mitochondria that was reduced by ∼50% ( P < 0.002) without a loss of respiratory control. Mitochondrial respiration was unaffected in tropomodulin-overexpressing transgenic mice, another model of cardiomyopathy. Western blotting for mitochondrial electron transfer subunits from mitochondria of CalTG mice revealed a 20–30% reduction in subunit 3 of complex I (ND3) and subunits I and IV of cytochrome oxidase (CO-I, CO-IV) when normalized to total mitochondrial protein or to the adenine nucleotide transporter (ANT) and compared with littermate controls ( P < 0.002). Impaired mitochondrial electron transport was associated with high levels of superoxide production in the CalTG mice. Taken together, these data indicate that calcineurin signaling affects mitochondrial energetics and superoxide production. The excessive production of superoxide may contribute to the development of cardiac failure.
49
Singh, Abhishek K., Ashley M. Wellendorf, Breanna Bohan, Daniel Gonzalez-Nieto, Luis C. Barrio, Ashwini S. Hinge, Marie-Dominique Filippi, and Jose A. Cancelas. "Mitochondrial Fate of Regenerative Hematopoietic Stem Cells Is Sequentially Controlled By Two Specific Conformations of Connexin-43." Blood 136, Supplement 1 (November 5, 2020): 32–33. http://dx.doi.org/10.1182/blood-2020-141676.
Full textAbstract:
Restricted mitochondrial metabolism with low mitochondrial reactive oxygen species (ROS) and membrane potential are essential properties of repopulating hematopoietic stem cells (HSC). Upon regenerative stress, as found after chemotherapy and/or radiotherapy, HSC exit quiescence, proliferate and differentiate into mature blood cells. Understanding the mechanism controlling hematopoiesis regeneration upon replicative stress is expected to provide molecular targets for amelioration of chemotherapy induced toxicity on HSC. Recent evidence demonstrates that the coordinated regulation of mitochondrial dynamics and the clearance of damaged mitochondria are the critical determinants of HSC fate decisions. Upon myeloablative stress, hematopoietic connexin 43 (H-Cx43), a major component of the gap junctions (GJ) present in the cell, lysosome and mitochondrial membranes, preserves the survival and efficient blood formation of regenerating HSC and progenitors (HSPC) by the transfer of damaging excess ROS, preventing HSPC apoptosis and lethal hematology failure. The protective role of H-Cx43 depends on the regulation of cell-contact dependent mitochondrial transfer to BM mesenchymal stromal cells. Mitochondrial homeostasis is maintained by coordinated regulation of mitochondrial fission, fusion and lysosome dependent mitophagy. We hypothesized that hematopoietic Cx43 may exert a mitochondrial autonomous activity affecting the ability of HSC to regenerate. We created HSC mitochondrial reporter mice with hematopoietic deficiency of Cx43(H-Cx43D/D) and analyzed mitochondrial dynamics and fate in quiescent and dividing HSC. While quiescent Cx43D/D HSC function normally, Cx43 deficiency results in increased mitochondrial ROS and membrane depolarization in cycling HSC. Time lapsed imaging of photo-converted mitochondria indicate that mitochondria of Cx43D/D cycling HSC split into highly-motile, smaller fragments. Interestingly, the activating phosphorylation (Ser616) of the mitochondrial fission protein, Drp1 and its accumulation within mitochondria is higher in Cx43D/D dividing HSC. The recruitment of Drp1 to mitochondria is regulated by mitochondrial membrane adaptors Mff and Fis1. Expression of Fis1, but not Mff, is significantly increased in Cx43D/D cycling HSC. In contrast, the components of mitochondrial fusion machinery Mfn2 and active Drp1 (phospho-Drp1-Ser637) are significantly attenuated in dividing Cx43D/D HSC, suggesting that HSC Cx43 promotes mitochondrial fusion and stability, and inhibits mitochondrial fragmentation. Increased mitochondrial fission in dividing Cx43D/D HSC facilitates mitophagy as indicated by increased co-localization of mitochondria with the ubiquitin kinase Pink1 which simultaneously recruits the E3 ubiquitin ligase Parkin, autophagosome p62 and Lc3, and the lysosomal membrane protein Lamp2 on the surface of dysfunctional mitochondria. Additionally, increased phosphorylation of Ampk (Tyr172) and Ulk1 (Ser555) in mitochondria of cycling Cx43D/D HSC demonstrate that H-Cx43 is a negative regulator of Ampk dependent mitophagy in diving HSC. Inhibition of the Drp1 GTPase activity by expression of the dominant negative Drp1-K38A mutant prevents mitochondrial fragmentation, motility and mitophagy of dividing Cx43D/D HSC, confirming that the inhibitory effect on mitophagy of Cx43 depends on its role on mitochondrial fission. Expression of Cx43 structure-function mutants (cys-less mutant with impaired head-to-head hemichannel docking, but not hemichannel function; and C-terminus truncated D257 mutant with impaired signaling and intramolecular interactions needed for channel gating) in H-Cx43D/D HSC demonstrated that the negative regulatory role of Cx43 on mitochondrial fission requires functional Cx43 hemichannels while the constitutive inhibitory effect of H-Cx43 on mitophagy depends on the formation of complete functional GJ channels. Our results identify for first time the sequential role of two distinct conformations of mitochondrial H-Cx43 dependent channels on the control of mitochondrial fate: fission and mitophagy, in cycling HSC. This data provides novel targets for ex-vivo intervention to preserve HSC activity by transfer of genetically manipulated mitochondria. Figure Disclosures Cancelas: TerumoBCT: Consultancy, Research Funding; Cerus Corp: Research Funding; Hemanext Inc.: Consultancy, Research Funding; Velico LLC: Consultancy, Research Funding; Cytosorbents: Research Funding; Westat Inc: Consultancy, Research Funding; US DoD: Research Funding; NIH: Consultancy, Research Funding.
50
Pedersen, H. S., P. Løvendahl, N. K. Nikolaisen, P. Holm, P. Hyttel, J. R. Nyengaard, F. Chen, and H. Callesen. "152 MITOCHONDRIAL DYNAMICS IN PRE- AND POSTPUBERTAL PIG OOCYTES BEFORE AND AFTER IN VITRO MATURATION." Reproduction, Fertility and Development 26, no. 1 (2014): 189. http://dx.doi.org/10.1071/rdv26n1ab152.
Full textAbstract:
Oocytes from prepubertal (PRE) or postpubertal (POST) pigs are used in, for example, somatic cell nuclear transfer and in vitro fertilization. Here we describe mitochondrial dynamics in pig oocytes of different sizes before and after in vitro maturation (IVM), isolated from PRE or POST animals. In PRE oocytes, inside-zona pellucida diameter was measured before and after IVM (μm; small: ≤110, medium: >110, large: ≥120) and used for evaluation of (1) mitochondrial numbers before maturation and (2) mitochondrial morphology and location before and after maturation in comparison with POST oocytes. Oocytes were processed for transmission electron microscopy (Acta Anat. 129:12). For assessment of mitochondrial numbers, paired dissector sections were collected at uniform intervals throughout the oocyte, and in each set of dissector sections a known area fraction was sampled for mitochondrial counting in physical dissectors (J. Microsc. 134:127). Total number of mitochondria was calculated, and oocyte volume was estimated by Cavalieri estimator (J. Microsc. 147:229). Data were analysed by ANOVA. Mitochondrial morphology was classified as elongated, round, shell-like, or compartmentalized; mitochondrial cristae as transverse or peripheral; and mitochondrial location as cortical, subcortical, or central. Before IVM, small PRE presented elongated and round mitochondria with transverse cristae; medium and large PRE presented round mitochondria with peripheral and transverse cristae; POST presented round mitochondria with peripheral cristae in all cases. After IVM, small and medium PRE had round mitochondria with peripheral cristae; medium PRE and POST had shell-like mitochondria with peripheral cristae; large PRE had compartmentalized mitochondria with peripheral cristae. Before IVM, small PRE displayed cortical mitochondrial location, whereas the location in other groups was cortical and central. After IVM, mitochondria were located centrally in some large PRE and in all POST. Mitochondrial number increased during oocyte growth proportional to the increase in oocyte volume (Table 1). Shell-like and compartmentalized mitochondria indicate (1) dividing mitochondria (increasing mitochondrial numbers during maturation), or (2) apoptosis-related mitochondrial fission (compromised oocytes after maturation). After IVM, mitochondria seemed to reach the final central position most consistently in POST. These differences may partly explain the higher developmental competence in larger PRE and POST oocytes. Table 1.Mitochondrial number and oocyte volume in pre- and postpubertal pigs