Добірка наукової літератури з теми "Unipore calcique mitochondrial"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся зі списками актуальних статей, книг, дисертацій, тез та інших наукових джерел на тему "Unipore calcique mitochondrial".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Статті в журналах з теми "Unipore calcique mitochondrial"
1
Wang, Guang Jian, and Stanley A. Thayer. "NMDA-Induced Calcium Loads Recycle Across the Mitochondrial Inner Membrane of Hippocampal Neurons in Culture." Journal of Neurophysiology 87, no. 2 (February 1, 2002): 740–49. http://dx.doi.org/10.1152/jn.00345.2001.
Повний текст джерелаАнотація:
Mitochondria sequester N-methyl-d-aspartate (NMDA)-induced Ca2+ loads and regulate the shape of intracellular Ca2+ concentration ([Ca2+]i) responses in neurons. When isolated mitochondria are exposed to high [Ca2+],Ca2+ enters the matrix via the uniporter and returns to the cytosol by Na+/Ca2+ exchange. Released Ca2+ may re-enter the mitochondrion recycling across the inner membrane dissipating respiratory energy. Ca2+ recycling, the continuous uptake and release of Ca2+ by mitochondria, has not been described in intact neurons. Here we used single-cell microfluorimetry to measure [Ca2+]i and mitochondrially targeted aequorin to measure matrix Ca2+ concentration ([Ca2+]mt) to determine whether Ca2+ recycles across the mitochondrial inner membrane in intact neurons following treatment with NMDA. We used ruthenium red and CGP 37157 to block uptake via the uniporter and release via Na+/Ca2+exchange, respectively. As predicted by the Ca2+recycling hypothesis, blocking the uniporter immediately following challenge with 200 μM NMDA produced a rapid and transient increase in cytosolic Ca2+ without a corresponding increase in matrix Ca2+. Blocking mitochondrial Ca2+ release produced the opposite effect, depressing cytosolic Ca2+ levels and prolonging the time for matrix Ca2+ levels to recover. The Ca2+ recycling hypothesis uniquely predicts these reciprocal changes in the Ca2+ levels between the two compartments. Ca2+ recycling was not detected following treatment with 20 μM NMDA. Thus Ca2+recycling across the inner membrane was more pronounced following treatment with a high relative to a low concentration of NMDA, consistent with a role in Ca2+-dependent neurotoxicity.
2
Dubinin, Mikhail V., Eugeny Yu Talanov, Kirill S. Tenkov, Vlada S. Starinets, Natalia V. Belosludtseva, and Konstantin N. Belosludtsev. "The Effect of Deflazacort Treatment on the Functioning of Skeletal Muscle Mitochondria in Duchenne Muscular Dystrophy." International Journal of Molecular Sciences 21, no. 22 (November 19, 2020): 8763. http://dx.doi.org/10.3390/ijms21228763.
Повний текст джерелаАнотація:
Duchenne muscular dystrophy (DMD) is a severe hereditary disease caused by a lack of dystrophin, a protein essential for myocyte integrity. Mitochondrial dysfunction is reportedly responsible for DMD. This study examines the effect of glucocorticoid deflazacort on the functioning of the skeletal-muscle mitochondria of dystrophin-deficient mdx mice and WT animals. Deflazacort administration was found to improve mitochondrial respiration of mdx mice due to an increase in the level of ETC complexes (complexes III and IV and ATP synthase), which may contribute to the normalization of ATP levels in the skeletal muscle of mdx animals. Deflazacort treatment improved the rate of Ca2+ uniport in the skeletal muscle mitochondria of mdx mice, presumably by affecting the subunit composition of the calcium uniporter of organelles. At the same time, deflazacort was found to reduce the resistance of skeletal mitochondria to MPT pore opening, which may be associated with a change in the level of ANT2 and CypD. In this case, deflazacort also affected the mitochondria of WT mice. The paper discusses the mechanisms underlying the effect of deflazacort on the functioning of mitochondria and contributing to the improvement of the muscular function of mdx mice.
3
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.
Повний текст джерелаАнотація:
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.
4
Naon, Deborah, Marta Zaninello, Marta Giacomello, Tatiana Varanita, Francesca Grespi, Sowmya Lakshminaranayan, Annalisa Serafini, et al. "Critical reappraisal confirms that Mitofusin 2 is an endoplasmic reticulum–mitochondria tether." Proceedings of the National Academy of Sciences 113, no. 40 (September 19, 2016): 11249–54. http://dx.doi.org/10.1073/pnas.1606786113.
Повний текст джерелаАнотація:
The discovery of the multiple roles of mitochondria–endoplasmic reticulum (ER) juxtaposition in cell biology often relied upon the exploitation of Mitofusin (Mfn) 2 as an ER–mitochondria tether. However, this established Mfn2 function was recently questioned, calling for a critical re-evaluation of Mfn2’s role in ER–mitochondria cross-talk. Electron microscopy and fluorescence-based probes of organelle proximity confirmed that ER–mitochondria juxtaposition was reduced by constitutive or acute Mfn2 deletion. Functionally, mitochondrial uptake of Ca2+ released from the ER was reduced following acute Mfn2 ablation, as well as in Mfn2−/− cells overexpressing the mitochondrial calcium uniporter. Mitochondrial Ca2+ uptake rate and extent were normal in isolated Mfn2−/− liver mitochondria, consistent with the finding that acute or chronic Mfn2 ablation or overexpression did not alter mitochondrial calcium uniporter complex component levels. Hence, Mfn2 stands as a bona fide ER–mitochondria tether whose ablation decreases interorganellar juxtaposition and communication.
5
Tedesco, Scattolini, Albiero, Bortolozzi, Avogaro, Cignarella, and Fadini. "Mitochondrial Calcium Uptake Is Instrumental to Alternative Macrophage Polarization and Phagocytic Activity." International Journal of Molecular Sciences 20, no. 19 (October 8, 2019): 4966. http://dx.doi.org/10.3390/ijms20194966.
Повний текст джерелаАнотація:
Macrophages are highly plastic and dynamic cells that exert much of their function through phagocytosis. Phagocytosis depends on a coordinated, finely tuned, and compartmentalized regulation of calcium concentrations. We examined the role of mitochondrial calcium uptake and mitochondrial calcium uniporter (MCU) in macrophage polarization and function. In primary cultures of human monocyte-derived macrophages, calcium uptake in mitochondria was instrumental for alternative (M2) macrophage polarization. Mitochondrial calcium uniporter inhibition with KB-R7943 or MCU knockdown, which prevented mitochondrial calcium uptake, reduced M2 polarization, while not affecting classical (M1) polarization. Challenging macrophages with E. coli fragments induced spikes of mitochondrial calcium concentrations, which were prevented by MCU inhibition or silencing. In addition, mitochondria remodelled in M2 macrophages during phagocytosis, especially close to sites of E. coli internalization. Remarkably, inhibition or knockdown of MCU significantly reduced the phagocytic capacity of M2 macrophages. KB-R7943, which also inhibits the membrane sodium/calcium exchanger and Complex I, reduced mitochondria energization and cellular ATP levels, but such effects were not observed with MCU silencing. Therefore, phagocytosis inhibition by MCU knockdown depended on the impaired mitochondrial calcium buffering rather than changes in mitochondrial and cellular energy status. These data uncover a new role for MCU in alternative macrophage polarization and phagocytic activity.
6
Zhang, Linlin, Jingyi Qi, Xu Zhang, Xiya Zhao, Peng An, Yongting Luo, and Junjie Luo. "The Regulatory Roles of Mitochondrial Calcium and the Mitochondrial Calcium Uniporter in Tumor Cells." International Journal of Molecular Sciences 23, no. 12 (June 15, 2022): 6667. http://dx.doi.org/10.3390/ijms23126667.
Повний текст джерелаАнотація:
Mitochondria, as the main site of cellular energy metabolism and the generation of oxygen free radicals, are the key switch for mitochondria-mediated endogenous apoptosis. Ca2+ is not only an important messenger for cell proliferation, but it is also an indispensable signal for cell death. Ca2+ participates in and plays a crucial role in the energy metabolism, physiology, and pathology of mitochondria. Mitochondria control the uptake and release of Ca2+ through channels/transporters, such as the mitochondrial calcium uniporter (MCU), and influence the concentration of Ca2+ in both mitochondria and cytoplasm, thereby regulating cellular Ca2+ homeostasis. Mitochondrial Ca2+ transport-related processes are involved in important biological processes of tumor cells including proliferation, metabolism, and apoptosis. In particular, MCU and its regulatory proteins represent a new era in the study of MCU-mediated mitochondrial Ca2+ homeostasis in tumors. Through an in-depth analysis of the close correlation between mitochondrial Ca2+ and energy metabolism, autophagy, and apoptosis of tumor cells, we can provide a valuable reference for further understanding of how mitochondrial Ca2+ regulation helps diagnosis and therapy.
7
MONTERO, Mayte, Carmen D. LOBATÓN, Esther HERNÁNDEZ-SANMIGUEL, Jaime SANTODOMINGO, Laura VAY, Alfredo MORENO, and Javier ALVAREZ. "Direct activation of the mitochondrial calcium uniporter by natural plant flavonoids." Biochemical Journal 384, no. 1 (November 9, 2004): 19–24. http://dx.doi.org/10.1042/bj20040990.
Повний текст джерелаАнотація:
During cell activation, mitochondria play an important role in Ca2+ homoeostasis due to the presence of a fast and specific Ca2+ channel in its inner membrane, the mitochondrial Ca2+ uniporter. This channel allows mitochondria to buffer local cytosolic [Ca2+] changes and controls the intramitochondrial Ca2+ levels, thus modulating a variety of phenomena from respiratory rate to apoptosis. We have described recently that SB202190, an inhibitor of p38 MAPK (mitogen-activated protein kinase), strongly activated the uniporter. We show in the present study that a series of natural plant flavonoids, widely distributed in foods, produced also a strong stimulation of the mitochondrial Ca2+ uniporter. This effect was of the same magnitude as that induced by SB202190 (an approx. 20-fold increase in the mitochondrial Ca2+ uptake rate), developed without measurable delay and was rapidly reversible. In intact cells, the mitochondrial Ca2+ peak induced by histamine was also largely increased by the flavonoids. Stimulation of the uniporter by either flavonoids or SB202190 did not require ATP, suggesting a direct effect on the uniporter or an associated protein which is not mediated by protein phosphorylation. The most active compound, kaempferol, increased the rate of mitochondrial Ca2+ uptake by 85±15% (mean±S.E.M., n=4) and the histamine-induced mitochondrial Ca2+ peak by 139±19% (mean±S.E.M., n=5) at a concentration of 1 μM. Given that flavonoids can reach this concentration range in plasma after ingestion of flavonoid-rich food, these compounds could be modulating the uniporter under physiological conditions.
8
Satrústegui, Jorgina, Beatriz Pardo, and Araceli del Arco. "Mitochondrial Transporters as Novel Targets for Intracellular Calcium Signaling." Physiological Reviews 87, no. 1 (January 2007): 29–67. http://dx.doi.org/10.1152/physrev.00005.2006.
Повний текст джерелаАнотація:
Ca2+signaling in mitochondria is important to tune mitochondrial function to a variety of extracellular stimuli. The main mechanism is Ca2+entry in mitochondria via the Ca2+uniporter followed by Ca2+activation of three dehydrogenases in the mitochondrial matrix. This results in increases in mitochondrial NADH/NAD ratios and ATP levels and increased substrate uptake by mitochondria. We review evidence gathered more than 20 years ago and recent work indicating that substrate uptake, mitochondrial NADH/NAD ratios, and ATP levels may be also activated in response to cytosolic Ca2+signals via a mechanism that does not require the entry of Ca2+in mitochondria, a mechanism depending on the activity of Ca2+-dependent mitochondrial carriers (CaMC). CaMCs fall into two groups, the aspartate-glutamate carriers (AGC) and the ATP-Mg/Picarriers, also named SCaMC (for short CaMC). The two mammalian AGCs, aralar and citrin, are members of the malate-aspartate NADH shuttle, and citrin, the liver AGC, is also a member of the urea cycle. Both types of CaMCs are activated by Ca2+in the intermembrane space and function together with the Ca2+uniporter in decoding the Ca2+signal into a mitochondrial response.
9
Tsai, Chen-Wei, Yujiao Wu, Ping-Chieh Pao, Charles B. Phillips, Carole Williams, Christopher Miller, Matthew Ranaghan, and Ming-Feng Tsai. "Proteolytic control of the mitochondrial calcium uniporter complex." Proceedings of the National Academy of Sciences 114, no. 17 (April 10, 2017): 4388–93. http://dx.doi.org/10.1073/pnas.1702938114.
Повний текст джерелаАнотація:
The mitochondrial calcium uniporter is a Ca2+-activated Ca2+ channel complex mediating mitochondrial Ca2+ uptake, a process crucial for Ca2+ signaling, bioenergetics, and cell death. The uniporter is composed of the pore-forming MCU protein, the gatekeeping MICU1 and MICU2 subunits, and EMRE, a single-pass membrane protein that links MCU and MICU1 together. As a bridging subunit required for channel function, EMRE could paradoxically inhibit uniporter complex formation if expressed in excess. Here, we show that mitochondrial mAAA proteases AFG3L2 and SPG7 rapidly degrade unassembled EMRE using the energy of ATP hydrolysis. Once EMRE is incorporated into the complex, its turnover is inhibited >15-fold. Protease-resistant EMRE mutants produce uniporter subcomplexes that induce constitutive Ca2+ leakage into mitochondria, a condition linked to debilitating neuromuscular disorders in humans. The results highlight the dynamic nature of uniporter subunit assembly, which must be tightly regulated to ensure proper mitochondrial responses to intracellular Ca2+ signals.
10
Zavodnik, I. B. "Mitochondria, calcium homeostasis and calcium signaling." Biomeditsinskaya Khimiya 62, no. 3 (2016): 311–17. http://dx.doi.org/10.18097/pbmc20166203311.
Повний текст джерелаАнотація:
Са2+ is a very important and versatile intracellular signal which controls numerous biochemical and physiological (pathophysiological) processes in the cell. Good evidence exists that mitochondria are sensors, decoders and regulators of calcium signaling. Precise regulation of calcium signaling in the cell involves numerous molecular targets, which induce and decode changes of Са2+ concentrations in the cell (pumps, channels, Са2+-binding proteins, Са2+-dependent enzymes, localized in the cytoplasm and organelles). Mitochondrial Са2+ uniporter accumulates excess of Са2+ in mitochondria, while Na+/Са2+- and H+/Са2+-antiporters extrude Са2+ in the cytoplasm. Mitochondrial Са2+ overloading results in formation of mitochondria permeability transition pores which play an important role in cell death under many pathological conditions. Mitochondria regulate Са2+ homeostasis and control important cellular functions such as metabolism, proliferation, survival. Identification of cellular and mitochondrial Ca2+ transporters and understanding their functional mechanisms open up new prospects for their using as therapeutic targets
Дисертації з теми "Unipore calcique mitochondrial"
1
Lamonzie, Elodie. "Nouvelles stratégies thérapeutiques cardiaques portées par le kaempférol et les vésicules extracellulaires." Electronic Thesis or Diss., Université de Montpellier (2022-....), 2025. http://www.theses.fr/2025UMONT002.
Повний текст джерелаАнотація:
La recherche de molécules ou d'outils thérapeutiques innovants est au cœur des préoccupations scientifiques. Au niveau cardiaque, le développement de pathologies comme l'ischémie-reperfusion et la cardiomyopathie diabétique a des effets délétères sur la structure et la fonction du cœur. Dans notre étude, nous avons testé deux substances prometteuses : le kaempférol et les vésicules extracellulaires portant le morphogène Sonic Hedgehog (VESHH).Le kaempférol, un polyphénol présent dans les fruits et légumes, possède des propriétés anti-inflammatoires, antioxydantes et anti-apoptotiques. Il a montré des effets anti-arythmiques, notamment dans la cardiomyopathie diabétique, en activant le complexe MCU qui régule l'entrée du calcium dans la mitochondrie. Cependant, les effets précis du kaempférol sur le complexe MCU en fonction de son assemblage restent indéterminés. D’une part, nous avons démontré que le calcium modifie la conformation des sous-unités MICU1, permettant au kaempférol de se fixer et de réarranger ces sous-unités. D’autre part, les effets du kaempférol sur les propriétés biophysiques du complexe MCU sont régis par le ratio MICU1/MCU. En effet, le kaempférol n’induit aucune modification des courants unitaires MCUC sur un fort ratio MICU1/MCU, tel que trouvé dans des particules sub-mitochondriales de cœur. En revanche, l’effet activateur du kaempférol sur les propriétés biophysiques du MCUC est retrouvé avec un faible ratio MICU1/MCU dans des SMP de foie dès 1 µM de calcium. Ainsi, l'utilisation du kaempférol, afin d’activer l’absorption de calcium mitochondrial par le MCUC, doit être adaptée en fonction de la pathologie cardiaque et de ses dysfonctions métaboliques, mais aussi du ratio MICU1/MCU. De plus, la diversité d'effets du kaempférol rend son utilisation clinique complexe et incertaine selon les pathologies.Les VESHH ont été testées dans un modèle d'ischémie-reperfusion de 28 jours chez le porc. Produites à partir de lymphocytes T, ces VESHH n'ont pas montré d'effets bénéfiques sur les lésions cardiaques, quel que soit le temps de reperfusion, en raison de leur inactivité. Si les résultats des VESHH se révèlent peu concluants dans cette étude, des travaux antérieurs mettent en avant leur potentiel thérapeutique dans l'ischémie-reperfusion cardiaque au bout de 24 heures de reperfusion chez le gros animal, bien plus prometteur lorsqu'elles sont biologiquement actives, en diminuant les marqueurs de souffrance myocardique, la taille de la lésion infarcie et même les arythmies ventriculaires lors de la reperfusion.En résumé, bien que le kaempférol et les VESHH soient des approches thérapeutiques différentes, ciblent des mécanismes différents et des pathologies cardiaques distinctes, elles apparaissent comme des molécules prometteuses. Des recherches supplémentaires seront nécessaires pour approfondir leur potentiel en tant que traitements thérapeutiquesThe search for innovative molecules or therapeutic tools is at the heart of scientific concerns. In cardiology, the development of pathologies such as ischemia-reperfusion and diabetic cardiomyopathy has deleterious effects on the structure and function of the heart. In our study, we tested two promising substances: kaempferol and extracellular vesicles carrying the Sonic Hedgehog morphogen (EVSHH).Kaempferol, a polyphenol found in fruits and vegetables, has anti-inflammatory, antioxidant, and anti-apoptotic properties. It has shown anti-arrhythmic effects, particularly in diabetic cardiomyopathy, by activating the MCU complex that regulates calcium entry into the mitochondria. However, the precise effects of kaempferol on the MCU complex depending on its assembly remain undetermined. On one hand, we demonstrated that calcium modifies the conformation of MICU1 subunits, allowing kaempferol to bind and rearrange these subunits. On the other hand, the effects of kaempferol on the biophysical properties of the MCU complex are governed by the MICU1/MCU ratio. Indeed, kaempferol does not induce any modification of MCUC unitary currents with a high MICU1/MCU ratio, as found in heart sub-mitochondrial particles. Conversely, the activating effect of kaempferol on the biophysical properties of MCUC is observed with a low MICU1/MCU ratio in liver SMPs from 1 µM calcium. Thus, the use of kaempferol to activate mitochondrial calcium uptake by MCUC must be adapted according to the cardiac pathology and its metabolic dysfunctions, as well as the MICU1/MCU ratio. Moreover, the diversity of kaempferol's effects makes its clinical use complex and uncertain depending on the targeted pathologies.EVSHH were tested in a 28-day ischemia-reperfusion model in pigs. Produced from T lymphocytes, EVSHH did not show beneficial effects on cardiac damage, regardless of the reperfusion time, due to their inactivity. While the results of EVSHH are inconclusive in this study, previous work highlights their therapeutic potential in cardiac ischemia-reperfusion after 24 hours of reperfusion in large animals, being much more promising when they are biologically active, by reducing markers of myocardial injury, infarct size, and even ventricular arrhythmias during reperfusion.In summary, although kaempferol and EVSHH are different therapeutic approaches targeting different mechanisms and distinct cardiac pathologies, they appear as promising molecules. Further research will be necessary to deepen their potential as therapeutic treatments
2
Doonan, Patrick John. "Mitochondrial Calcium Uptake: LETM1 and MICU1 Are Mitochondrial Proteins That Regulate Mitochondrial Calcium Homeostasis and Cellular Bioenergetics." Diss., Temple University Libraries, 2012. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/214818.
Повний текст джерелаАнотація:
BiochemistryPh.D.
Mitochondrial calcium (Ca2+) uptake has been studied for over five decades, with crucial insights into its underlying mechanisms enabled by development of the chemi-osmotic hypothesis and appreciation of the considerable voltage present across the inner mitochondrial membrane (ΔΨm) generated by proton pumping by the respiratory chain (Carafoli, 1987; Nicholls, 2005). However, the molecules that regulate mitochondrial Ca2+ uptake have only recently been identified (Jiang et. al., 2009; Perocchi et. al., 2010) and further work was needed to clarify how these molecules regulate mitochondrial Ca2+ uptake. Leucine Zipper EF hand containing Transmembrane Protein 1 (LETM1) acts as a regulator of mitochondrial Ca2+ uptake distinct from the mitochondrial Ca2+ uniporter (MCU) pathway (Jiang et. al., 2009). However, a controversy exists regarding the function of LETM1 (Nowikovsky et. al., 2004). Therefore, I asked if LETM1 played a role in mitochondrial Ca2+ uptake and if LETM1 regulated cellular bioenergetics and basal autophagy. To further characterize mitochondrial calcium uptake, we asked how Mitochondrial Calcium Uptake 1 (MICU1) regulates MCU activity by quantifying basal mitochondrial Ca2+ and MCU uptake rates in MICU1 ablated cells. The following work characterizes the molecules that regulate mitochondrial Ca2+ uptake and their mechanistic function on decoding calcium signals. Since LETM1 is the Ca2+/H+ antiporter, I hypothesize that alterations in LETM1 expression and activity will decrease mitochondrial Ca2+ uptake and will result in impaired mitochondrial bioenergetics. As a regulator of free intracellular Ca2+, mitochondrial Ca2+ uptake and the orchestra of its regulatory molecules have been implicated in many human diseases. Mitochondria act both upstream by regulating cytosolic Ca2+ concentration and as downstream effectors that respond to Ca2+ signals. Recently, LETM1 was proposed as a mitochondrial Ca2+/H+ antiporter (Jiang et. al., 2009); however characterization of the functional role of LETM1-mediated Ca2+ transfer remained unstudied. Therefore the specific aims of this project were to determine how LETM1 regulates Ca2+ homeostasis and bioenergetics under physiological settings. Secondly, this project aimed to characterize how LETM1-dependent Ca2+ signaling regulates ROS production and autophagy. The data presented here confirmed that LETM1 knockdown significantly impairs mitochondrial Ca2+ uptake. Furthermore, in-depth approaches including either deletion of EF-hand or mutation of critical EF-hand residues (D676A D688KLETM1) impaired histamine (GPCR agonist)-induced mitochondrial Ca2+ uptake. Knockdown of LETM1 resulted in bioenergetic collapse and promoted LC3-positive multilamellar vesicle formation, indicative of autophagy induction. Interestingly, knockdown of LETM1 significantly reduced complex IV but not complex I and complex II-mediated oxygen consumption rate (OCR). In contrast, cellular NADH and mitochondrial membrane potential (ΔΨm) were unaltered in both control and LETM1 knockdown cells. LETM1 has been implicated in formation of the supercomplexes of the electron transport chain (Tamai et. al., 2008). In support, these studies show that LETM1 knockdown results in increased reactive oxygen species (ROS) production. These results for the first time demonstrate that LETM1 controls cellular bioenergetics through regulation of mitochondrial Ca2+ and ROS. MICU1 was identified as an essential regulator of the mitochondrial Ca2+ uniporter (Perocchi et. al., 2010). Therefore, this project specifically aimed to determine how MICU1 regulates the mitochondrial Ca2+ uniporter. Interestingly, the data presented here suggest that MICU1 is not necessary for uniporter activity. Instead, loss of MICU1 caused mitochondria to constitutively load Ca2+ at rest which resulted in a host of cellular phenotypes. This result led to further questions on how MICU1 knockdown affects cellular bioenergetics and if MICU1 is essential for cell survival under stress. MICU1 ablation influenced pyruvate dehydrogenase activity and ROS production. Subsequent investigations demonstrated that increased basal ROS left cells poised to ceramide-induced cell death thereby suggesting the role of MICU1 in cell survival. Collectively, the data presented here show that MICU1 is necessary to control constitutive mitochondrial Ca2+ uptake during rest. This work demonstrates that LETM1 regulates a distinct mode of mitochondrial Ca2+ uptake pathway whereas MICU1 controls mitochondrial Ca2+ uniporter activity. Further studies are required to uncover the potential role of these two mitochondrial-resident Ca2+ regulators in health and disease.
Temple University--Theses
3
Rysted, Jacob Eugene. "Molecular mechanisms and functions of mitochondrial calcium transport in neurons." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6632.
Повний текст джерелаАнотація:
During neuronal activity mitochondria alter cytosolic Ca2+ signaling by buffering then releasing Ca2+ in the cytosol. This calcium transport by mitochondria affects the amplitude, duration, and spacial profile of the Ca2+ signal in the cytosol of neurons. This buffering by mitochondria has been shown to affect a variety of neuronal functions including: neurotransmission, gene expression, cell excitability, and cell death. Recently, researchers discovered that the protein CCDC109A (mitochondrial Ca2+ uniporter) was the protein responsible for mitochondrial Ca2+ uptake. Using a genetic knockout (KO) mouse model for the mitochondrial Ca2+ uniporter (MCU) my research investigated the role of MCU in neuronal function. In cultured central and peripheral neurons, MCU-KO significantly reduced mitochondrial Ca2+ uptake while significantly increasing the amplitude of the cytosolic Ca2+ signal amplitude. Behaviorally, MCU-KO mice show a small but significant impairment in memory tasks: fear conditioning and Barnes maze. Using a maximal electroshock seizure threshold model of in vivo seizure activity my research found that MCU-KO significantly increases the threshold for maximal seizure activity in mice and significantly reduces seizure severity. In addition to mitochondrial Ca2+ uptake, my research also investigated the mechanisms involved in mitochondrial Ca2+ extrusion. The protein SLC8B1 (SLC24A6, NCLX) is the putative transporter responsible for the Na+/Ca2+ exchange, mitochondrial calcium extrusion. Using genetic NCLX-KO mice, our research found that in neurons NCLX contributes to cytosolic Ca2+ extrusion, but does seem to directly affect mitochondrial Ca2+ extrusion.
4
Plovanich, Molly. "The Molecular Characterization of the Mitochondrial Calcium Uniporter." Thesis, Harvard University, 2014. http://etds.lib.harvard.edu/hms/admin/view/63.
Повний текст джерелаАнотація:
By buffering cytosolic calcium, mitochondria can shape the magnitude and duration of intracellular calcium transients, which in turn govern key physiological events. Although controlled uptake of calcium into the matrix influences the rate of ATP production, excess calcium within the matrix triggers non-specific permeabilization of the mitochondrial inner membrane, resulting in cell death. Despite its importance in cellular physiology, the molecular identity of the mitochondrial calcium uniporter remained a mystery for nearly five decades. Recently, an approach inspired by comparative genomics was used to identify two proteins required for high-capacity mitochondrial calcium uptake. These include MICU1, an EF-hand protein that may function as a regulatory component by sensing calcium, and MCU, the channel-forming subunit of the uniporter. In this work, I explore two distinct areas within the growing field of molecular mitochondrial calcium biology. First, I discuss the identification of a new protein, MICU1-paralog EFHA1, and present data that implicates it in mitochondrial calcium uptake. Subsequently, I describe efforts to establish an in vitro system to characterize the channel activity of MCU, including my contribution to the development of a liposome-based assay for calcium transport and preliminary work aimed at reconstituting MCU transport activity in proteoliposomes.
5
Gherardi, Gaia. "The physiopathological role of mitochondrial calcium uptake in skeletal muscle homeostasis." Doctoral thesis, Università degli studi di Padova, 2017. http://hdl.handle.net/11577/3424681.
Повний текст джерелаАнотація:
In a wide variety of cell types, cytosolic Ca2+ transients, generated by physiological stimuli, elicit large increases in the [Ca2+] of the mitochondrial matrix, which in turn stimulate the Ca2+-sensitive dehydrogenases of the Krebs cycle. Rapid uptake is favored by the close proximity with the major Ca2+ store of the cell, namely the endoplasmic/sarcoplasmic reticulum (ER/SR), and thus by the exposure to high [Ca2+] microdomains. In addition, mitochondrial Ca2+ could contribute to the cellular homeostasis thanks to the existence of a sophisticated machinery, that allows this organelle to rapidly change its Ca2+ concentration (Rizzuto et al., 2012). This general picture is also apparent in skeletal muscle during contraction whereby agonist stimulation induces high amplitude mitochondrial Ca2+ increases in vivo (Rudolf et al., 2004), thus acting as buffers of the cytosolic [Ca2+] increase. Finally, mitochondrial Ca2+ stimulates aerobic metabolism and ATP production, that are essential for muscle activity. Indeed, mitochondria are the major source of ATP in oxidative fibres. However, excessive Ca2+ accumulation in mitochondria, a condition known as mitochondrial Ca2+ overload, can trigger cell death.
The recent molecular identification of the Mitochondrial Calcium Uniporter (MCU), the highly selective channel responsible for Ca2+ entry into mitochondria, allows the detailed investigation of its role in different aspects of skeletal muscle biology (De Stefani et al., 2011; Baughman et al., 2011).
The major goal of my PhD project was to address the role of mitochondrial Ca2+ in skeletal muscle homeostasis. For this purpose, we firstly investigated in vivo the effects of mitochondrial Ca2+ homeostasis in skeletal muscle function by overexpressing or silencing MCU by means of AAV vectors. We demonstrated that the modulation of MCU protein controls skeletal muscle size during both post-natal growth and adulthood. In detail, we observed an increase in fibre size in MCU-infected muscles. Conversely, MCU-silenced muscles displayed an atrophic phenotype. These striking phenomenon impinges on two major hypertrophic pathways, i.e. PGC-1α4 and IGF1-AKT. We thus explored two potential different mechanisms that could account for the MCU-dependent control of anabolic pathways, i) the activation of a mitochondria-to-nucleus signaling route, ii) the regulation of metabolites as signaling molecules.
Regarding the mitochondria-to-nucleus route, we carried out a study on the PGC-1α4 promoter activity, and we demonstrated that mitochondrial Ca2+ controls the promoter activity of PGC-1α4.
Concerning the involvement of cellular metabolism, we carried out steady-state metabolomics analyses of MCU-overexpressing and MCU-silencing muscles. We discovered a marked metabolic reprogramming in silenced muscles, including a clear shift from glucose metabolism toward preferential fatty acid β-oxidation.
Next, we generated a skeletal muscle specific mcu knockout mouse (mlc1f-Cre-mcu-/-), by crossing a mcu fl/fl mouse with a line expressing the Cre recombinase under the control of the myosin light chain 1f (mlc1f) promoter. We observed marginal difference in fibre size of mlc1f-Cre-mcu-/- skeletal muscles. However, when these mice were exercised on a treadmill using different training protocols, an impaired running capacity of mlc1f-Cre-mcu-/- became evident, indicating that mitochondrial Ca2+ accumulation is required to guarantee skeletal muscle performance.
Finally, it is well-established that Ca2+ plays a pivotal role in autophagy regulation. Thus, we decided to investigate this process in MCU-overexpressing and MCU-silencing muscles. We demonstrated that mitochondrial Ca2+ uptake modulation controls mitophagy without affecting bulk autophagy.
Taken together, these data indicate that mitochondrial Ca2+ uptake plays a pivotal role in the control of skeletal muscle trophism. Further investigations of MCU-dependent effects on skeletal muscle homeostasis represent an important task for the future. Indeed, this research will provide new possible targets for clinical intervention in all diseases characterized by muscle loss, such as dystrophies, cancer cachexia and aging.In diversi tipi cellulari, i transienti di Ca2+ citosolico, generati da stimoli fisiologici, provocano ampi aumenti della concentrazione di Ca2+ nella matrice mitocondriale, che, a loro volta, stimolano le deidrogenasi Ca2+-sensibili del ciclo di Krebs. Questo rapido accumulo è favorito dalla vicinanza al principale deposito di Ca2+ della cellula, il reticolo endo/sarcoplasmatico (RE/RS), e di conseguenza dalla generazione di microdomini ad elevata concentrazione di Ca2+. Inoltre, il Ca2+ mitocondriale contribuisce all’omeostasi cellulare grazie all’esistenza di un complesso macchinario che permette a questo organello di accumulare rapidamente grandi quantità di Ca2+ (Rizzuto et al., 2012). Questo situazione è presente anche nel muscolo scheletrico, in cui la stimolazione che genera contrazione induce ampi transienti di Ca2+ mitocondriale in vivo (Rudolf et al., 2004), che sono in grado di tamponare gli aumenti della concentrazione di Ca2+ citosolica. Infine, il Ca2+ mitocondriale stimola il metabolismo aerobico e la produzione di ATP, che sono essenziali per l’attività muscolare. Infatti, i mitocondri rappresentano la principale fonte di ATP nelle fibre ossidative. Tuttavia, un accumulo eccessivo di Ca2+ nei mitocondri può anche portare a morte cellulare. La recente scoperta dell’identità molecolare del Mitochondrial Calcium Uniporter (MCU), il canale altamente selettivo responsabile dell’entrata di Ca2+ nei mitocondri, permette lo studio dettagliato del suo ruolo nei diversi aspetti della biologia del muscolo scheletrico (Baughman et al., 2011; De Stefani et al., 2011). L’obiettivo principale del mio progetto di tesi è stato quello di scoprire il ruolo del Ca2+ mitocondriale nell’omeostasi del muscolo scheletrico. Per fare questo, per prima cosa abbiamo indagato in vivo come le funzioni muscolari vengono controllate dall’omeostasi mitocondriale del Ca2+ attraverso la sovraespressione o il silenziamento di MCU. Abbiamo dimostrato che la modulazione di MCU controlla la dimensione del muscolo scheletrico sia durante la crescita post-natale che nell’età adulta. In particolare, abbiamo osservato un aumento nella dimensione delle fibre nei muscoli infettati con MCU. Al contrario, i muscoli in cui MCU è stato silenziato risultano atrofici. Questo straordinario fenomeno dipende dal coinvolgimento delle due principali vie di segnalazione che mediano l’ipertrofia, ovvero PGC-1α4 e IGF1-AKT. Di conseguenza, abbiamo studiato due diversi meccanismi potenzialmente in grado di spiegare il controllo delle vie anaboliche dipendente da MCU, i) l’attivazione di una comunicazione diretta fra mitocondrio e nucleo, ii) l’azione di metaboliti come segnali. Per quanto riguarda la comunicazione mitocondrio-nucleo, abbiamo studiato l’attività del promotore di PGC-1α4, dimostrando che il Ca2+ mitocondriale la controlla. Invece, nel contesto dei metaboliti come molecole segnale, abbiamo svolto un’analisi metabolomica di muscoli in cui MCU è stato sovraespresso o silenziato. Abbiamo rilevato un notevole rimodellamento della rete metabolica nei muscoli silenziati, compresa una chiara deviazione dal metabolismo del glucosio verso la preferenziale ossidazione degli acidi grassi. In seguito, abbiamo generato un modello murino privo di mcu esclusivamente nel muscolo scheletrico (mlc1f-Cre-mcu-/-), incrociando un topo mcu fl/fl con una linea che esprime la Cre ricombinasi sotto il controllo del promotore per la catena leggera della miosina 1f (mlc1f). Abbiamo osservato differenze marginali per quanto riguarda la dimensione delle fibre muscolari di questo modello. Tuttavia, abbiamo poi sottoposto questi topi ad esercizio fisico, attraverso diversi protocolli di corsa su tapis roulant. In queste condizioni, è stata evidenziata una compromessa capacità di corsa, indicando che l’accumulo di Ca2+ mitocondriale è richiesto per garantire performance muscolari ottimali. Infine, è ampiamente riconosciuto che il Ca2+ giochi un ruolo fondamentale nella regolazione dell’autofagia. Abbiamo quindi deciso di studiare questo processo in muscoli in cui MCU è stato sovraespresso o silenziato. Abbiamo dimostrato che i segnali Ca2+ mitocondriali controllano selettivamente la via autofagica che degrada i mitocondri disfunzionali, la mitofagia. In conclusione, questi dati indicano che l’accumulo mitocondriale di Ca2+ controlla il trofismo del muscolo scheletrico. In futuro saranno necessari ulteriori studi per caratterizzare meglio gli effetti di MCU sull’omeostasi del muscolo scheletrico. Questo studio fornirà nuovi potenziali bersagli che sarà possibile utilizzare in clinica, in tutte quelle patologie caratterizzate dalla perdita di massa muscolare, come ad esempio le distrofie, la cachessia neoplastica e l’invecchiamento.
6
DE, MARCHI Elena. "Mitochondrial calcium uptake and release mechanisms as key regulators of cell life or death." Doctoral thesis, Università degli studi di Ferrara, 2014. http://hdl.handle.net/11392/2388964.
Повний текст джерелаАнотація:
Mitochondria are cellular organelles that play a key role in several physiological processes, including cell proliferation, differentiation, cell death and the regulation of cellular calcium (Ca2+) homeostasis.
Increases in mitochondrial Ca2+ activate several dehydrogenases and carriers, inducing enhance in the respiratory rate, H+ extrusion, and ATP production necessary for the correct energy state of the cell.
The mitochondrial Ca2+ uptake and release mechanisms are based on the utilization of gated channels for Ca2+ uptake and exchangers for release that are dependent upon the negative mitochondrial membrane potential, which represents the driving force for Ca2+ accumulation in the mitochondrial matrix.
In this thesis, the attention was focused on two mechanisms in particular, the mitochondrial Ca2+ influx system by the activity of Mitochondrial Calcium Uniporter (MCU) complex, and the high-conductance channel mitochondrial Permeability Transition Pore (mPTP), responsible for a state of non-selective permeability of the inner mitochondrial membrane (IMM); its opening in non-physiological conditions leads to Ca2+ release from mitochondria and triggers cell death mechanisms. Thus the maintenance of the mitochondrial Ca2+ homeostasis is essential for a proper balance between cell life or death.
In particular it will be discussed the possible involvement of MCU in the cell cycle, as the Ca2+ accumulation by MCU is important for the regulation of cell life and energy production. It will be shown that MCU is mainly expressed in specific phases of the cell cycle and this expression positive correlates with the mitochondrial membrane potential. MCU overexpression instead does not alter cell cycle phases.
It will also described the role of the c subunit of Fo ATP synthase in mitochondrial permeability transition (MPT) and it will be demonstrated to be a critical component of the mPTP complex. Finally it will be discussed the role of mPTP in mitochondrial Ca2+ efflux and it will be shown that it is a dispensable element for mitochondrial Ca2+ efflux in non-pathological conditions.
7
Lambert, Jonathan Paul. "MCUB REGULATES THE MOLECULAR COMPOSITION OF THE MITOCHONDRIAL CALCIUM UNIPORTER CHANNEL TO LIMIT MITOCHONDRIAL CALCIUM OVERLOAD DURING STRESS." Diss., Temple University Libraries, 2019. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/575724.
Повний текст джерелаАнотація:
Biomedical SciencesPh.D.
Mitochondrial Calcium (mCa2+) overload is a central event in myocardial-ischemia reperfusion (IR) injury that leads to metabolic derangement as well as activation of the mitochondrial permeability transition pore (mPTP). mPTP activation results in necrosis and loss of cardiomyocytes which results in acute death in some individuals while survivors are prone to developing heart failure and are predisposed to recurrent infarction events. mCa2+ has also long been known to activate cellular bioenergetics implicating mCa2+ in the highly metabolically demanding state of cardiac contractility. The mitochondrial calcium uniporter channel (mtCU) is a multi-subunit complex that resides in the inner mitochondrial membrane and is required for mitochondrial Ca2+ (mCa2+) uptake. Mitochondrial Calcium Uniporter B (MCUB, CCDC109B gene), a recently identified paralog of MCU, is reported to negatively regulate mCa2+ uptake; however, its precise regulation of uniporter function and contribution to cardiac physiology remain unresolved. Size exclusion chromatography of mitochondria isolated from ventricular tissue revealed MCUB was undetectable in the high-molecular weight (MW) fraction of sham animals (~700kD, size of functional mtCU), but 24 hours following myocardial ischemia-reperfusion injury (IR) MCUB was clearly observed in the high-MW fraction. To investigate how MCUB contributes to mtCU regulation we created a stable MCUB-/- HeLa cell line using CRISPR-Cas9n. MCUB deletion increased histamine-mediated mCa2+ transient amplitude by ~50% versus Wild-Type (WT) controls (mito-R-GECO1). Further, MCUB deletion increased mtCU capacitance (patch-clamp) and rate of [mCa2+] uptake. Fast protein liquid chromatography (FPLC) fractionation of the mtCU revealed that loss of MCUB increased MCU incorporation into the high-MW complex suggesting stoichiometric replacement and overall increase in functional mtCU complexes. Next, we generated a cardiac-specific, tamoxifen-inducible MCUB mouse model (CAG-CAT-MCUB x MCM; MCUB-Tg) to examine how the MCUB/MCU ratio regulates mtCU function and contributes to cardiac physiology. MCUB-Tg mice were infected with AAV9-mitycam (genetic mCa2+ reporter) and adult cardiomyocytes were isolated to record [mCa2+] transients during pacing using live cell imaging. Increasing the MCUB/MCU ratio decreased [mCa2+] peak amplitude by ~30% and significantly reduced the [mCa2+] uptake rate. FPLC assessment revealed MCUB was undetectable in the high-MW fraction of MerCreMer controls, but enriched in MCUB-Tg hearts. MCUB incorporation into the mtCU decreased the overall size of the uniporter and reduced the presence of channel gatekeepers, MICU1/2. Immunoprecipitations suggest that MCUB directly interacts with MCU but does not bind MICU1/2. These results suggest that MCUB replaces MCU in the mtCU and thereby modulates the association of MICU1/2 to regulate channel gating. Cardiomyocytes isolated from MCUB-Tg hearts displayed decreased maximal respiration and reserve capacity, which correlated with a severe impairment in isoproterenol-induced contractile reserve (LV invasive hemodynamics). MCUB-Tg cardiac mitochondria were resistant to Ca2+-induced mitochondrial swelling suggesting MCUB limits mitochondrial permeability transition. Further, MCUB-Tg mice subjected to in vivo myocardial IR revealed a ~50% decrease in infarct size per area-at-risk suggesting increased MCUB expression prevents mCa2+ overload and limits cell death. These data suggest that MCUB regulation of the mtCU is an endogenous compensatory mechanism to decrease mCa2+ overload during ischemic injury, but this expression is maladaptive to cardiac energetic responsiveness and contractility.
Temple University--Theses
8
Hartmann, Magnus [Verfasser]. "Characterization of Mitochondrial Calcium Uniporter in Barth Syndrome Models / Magnus Hartmann." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://d-nb.info/1213974925/34.
Повний текст джерела
9
Houlihan, Patrick Ryan. "The role of mitochondrial restructuring in neuronal calcium homeostasis and excitotoxicity." Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/2522.
Повний текст джерелаАнотація:
Mitochondrial Ca2+ buffering is an important physiological modulator of neuronal signaling and bioenergetics, but this propensity toward Ca2+ regulation proves pathological during excitotoxic insult. Specifically, excessive mitochondrial Ca2+ uptake is a key component of glutamate toxicity within the penumbra surrounding the ischemic core following stroke. This mitochondrial toxicity and Ca2+ dyshomeostasis may be visualized in real time as delayed calcium deregulation (DCD). DCD is a predictor of neuronal, excitoxic death, and is composed of three phases: 1) an initial response; 2) a latent period of elevated, but stable cytosolic Ca2+; and 3) failure of mitochondrial Ca2+ retention, termed deregulation. The duration of the latent period is an index of neuronal resistance.
Mitochondria are dynamic organelles that rapidly and reversibly undergo fission and fusion (MFF). MFF is tightly regulated by the phosphoregulation of fission inducing Drp1 at serine 656. Drp1-S656 phosphorelation is mediated by PKA/AKAP1, and it is dephosphorylated by PP2A/Bβ2. Phosphorylation of Drp1-S656 inactivates this contractile GTPase resulting in inhibition of mitochondrial fission and a shift toward elongated mitochondria. This PKA/AKAP1 dependent Drp1-S656 phosphorylation has proven to be neuroprotective. Likewise, attenuation of PP2A/Bβ2 signaling enhances neuronal survival during ischemia and excitotoxic insult.
Based on the mitochondrial buffering role in excitotoxicity and MFF modulation of neuronal survival, we began investigating the role of Ca2+ buffering as a function of MFF during glutamate toxicity. Noted above, resistance to excitoticity is visualized by the duration of the DCD latent period. Overexpression of AKAP1 in cultured hippocampal neurons greatly prolonged DCD latency in a PKA dependent manner, while Bβ2 ablation prolonged DCD latency by hours. Pharmacological modulation of PKA required PDE4 inhibition to reproduce the AKAP1 observations. Preliminary experiments studying the effect of Bβ2 overexpression on matrix Ca2+ load suggests possible mechanism of MFF regulated of matrix Ca2+ accumulation. Using mtPericam DRG neurons as a model system for individual mitochondrial Ca2+ recording, we discovered impaired extrusion kinetics in mitochondria fragmented by both Drp1 and Bβ2 overexpression. Ca2+ uptake was comparable to that of control. Extreme elongation of mitochondria via dominant negative Drp1-K38A enhanced recovery.
Understanding these observations, however, requires knowledge of the mitochondrial Ca2+ buffering mechanism. Mitochondrial uptake candidates include MCU and ccdc109b. Our neuronal characterization of MCU confirms a role in mitochondrial Ca2+ buffering, but not a requirement; other components must be involved. Ccdc109b remains an inconclusive candidate, but may be an important regulator of MCU. Mitochondrial efflux transporters include Letm1 and NCLX. Though Letm1 observations are hindered by control artifact, preliminary evidence supports a role in extrusion. The role of NCLX is complicated by possible tissue specificity. Functional expression experiments utilizing Na+ free Li+ external solution suggests absence of NCLX in hippocampal neurons; DRG neurons were capable of Li+ exchange. The above observations confirm the significance of mitochondrial Ca2+ extrusion in neuronal survival. Understanding the mechanisms and regulation of mitochondrial Ca2+ transport has the potential to provide novel therapeutic targets in pathologies of excitotoxic etiology.
10
campesan, marika. "THE ROLE OF THE MITOCHONDRIAL CALCIUM UNIPORTER (MCU) IN THE CARDIAC INJURY INDUCED BY ISCHEMIA AND REPERFUSION." Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3424426.
Повний текст джерелаАнотація:
Mitochondrial Ca2+ uptake has been suggested to contribute to the cardiac injury induced by ischemia reperfusion. This notion has been derived from studies using pharmacological approaches due to the lack of information in protein involved in mitochondrial Ca2+ uptake (Ferrari, Di Lisa et al. 1982). The recent identification of the molecular identity of the mitochondrial Ca2+ uniporter (MCU) (De Stefani, Raffaello et al. 2011) allows a genetic approaches. Based on the available notion MCU deletion could be protected against I/R injury , that should be exacerbated by MCU overexpression. The present result provide a more complex picture where by a model increase in mitochondrial Ca2+ elicits cardioprotection that is lost under condition of mitochondrial Ca2+ overload.
Neonatal rat ventricular myocytes (NRVMs) overexpressing MCU by adenovirus infection showed a reduction in I/R-induced cell death as compared to wild type (wt) cells (41.82% ±8.37 vs 60.44% ±11.68, p<0.05). The in vitro evidence of cardioprotection was confirmed also ex vivo in perfused hearts overexpressing MCU by means of adenoassociated virus infection. Indeed, reperfusion after 40 min of global ischemia resulted in a significant decrease of lactate dehydrogenase release as compared to wt hearts (16.14 ±11.69 vs 67.01 ±0.07). This increased tolerance to I/R injury was associated with a large decrease in levels of reactive oxygen species (ROS) upon reperfusion. However, starting at 12 h after infection NRVMs displayed a slight increase in ROS levels associated with an increase in Akt phosphorylation (1.98± 0.06 fold) leading to the activation of this pro-survival kinase. Upstream of Akt, protein phosphatase 2A (PP2A) was more phosphorylated (2.8 ± 0.26 fold) resulting in its inactivation. Notably, Akt activation is abolished by antioxidants treatment.
Overall, these findings suggest that a slight increase in mitochondrial Ca2+ induced by MCU overexpression triggers a protective response involving a mild oxidative stress that eventually stimulates the activity of survival pathways. The protection by MCU overexpression was abolished when a further increase in mitochondrial Ca2+ was induced by the co-expression of MICU1. This latter evidence confirms that mitochondrial Ca2+ overload is a determining factor in the loss of cardiac viability occurring during post ischemic reperfusion. Therefore, the balance between protection and injury appears to be modulated by levels of intramitochondrial Ca2+. In this respect, the results of this Thesis provide novel evidence that a mild increase in mitochondrial Ca2+ elicits cardioprotection by stimulating ROS formation. It is tempting to speculate that this mechanism is involved also in the protective effect against cardiac diseases induced by exercise.L’uptake di Ca2+ mitocondriale contribuisce al danno cardiaco indotto da ischemia/riperfusione. Questo concetto è derivato da numerosi studi che hanno valutato il ruolo della proteina deputata all’uptake di Ca2+ mitocondriale servendosi di un approccio farmacologico. Tuttavia, la recente identificazione della struttura molecolare del canale responsabile dell’uptake di calcio definito MCU, ha reso possibile un approccio di tipo genetico, evitando i numerosi effetti collaterali degli inibitori farmacologici. Basandosi su i dati finora raccolti si presuppone che il silenziamento di MCU porti ad una riduzione del danno cardiaco in seguito ad I/R, e al contrario la sua sovraespressione ad un aumento del danno. Tuttavia i dati presentati in questa tesi mostrano un quadro più complesso in cui un moderato aumento del Ca2+ induce un effetto cardioprotettivo, che invece viene abrogato da un eccessivo carico di Ca2+ a livello mitocondriale. Cardiomiociti neonatali di ratto sovraesprimenti MCU tramite un infezione con adenovirus, mostrano una riduzione della mortalità sottoposti ad un protocollo di I/R (41.82%±8.37 vs 60.44%±11.68, p<0.05). L’evidenzia di questo effetto cardioprotettivo viene confermato anche da dati ottenuti ex vivo, in topi infettati con un virus adeno-associato di tipo 9 codificante per MCU-flag. Il cuore isolato sovraesprimente MCU sottoposto ad un protocollo di I/R in Langendorff mostra una riduzione della mortalità se comparato ad animali controllo (17.14±7.71 vs 30.16 ±10.35). Questa marcata riduzione della mortalità è accompagnata da una riduzione dello stress ossidativo in seguito all’evento post ischemico. Tuttavia, i cardiomiociti neonatali sovraesprimenti MCU mostrano un aumento dei ROS a livello basale, che correla con l’attivazione di Akt, chinasi coinvolta nei meccanismi di sopravvivenza cellulare. PP2A, fosfatasi coinvolta nella regolazione a monte di Akt, risulta essere più fosforilata quando MCU è sovraespresso, risultando perciò inattiva. Inoltre, l’attivazione di Akt viene abolita in seguito al trattamento con antiossidanti. Queste evidenze suggeriscono che un moderato aumento dell’uptake di Ca2+ mitocondriale indotto dalla sovraespressione di MCU sia responsabile dell’attivazione di un meccanismo di cardioprotezione che porta all’attivazione di meccanismi di sopravvivenza cellulare. Tuttavia, la cardioprotezione indotta dalla sola sovraespressione di MCU viene abrogata dalla co-espressione di MCU e MICU1, che determinano un massivo aumento di Ca2+ mitocondriale. Quest’ultima osservazione conferma che l’overload di Ca2+ mitocondriale è un fattore determinante nella mortalità indotta dal danno ischemico. Inoltre, appare evidente che il livello di Ca2+ mitocondriale sia il fattore determinante tra danno e protezione cardiaca. Questa tesi dimostra come un moderato aumento di Ca2+ mitocondriale possa determinare un effetto cardio-protettivo mediato da ROS. Inoltre, si potrebbe speculare che questo meccanismo di protezione rimandi all’effetto cardio-protettivo indotto dall’esercizio fisico.
Книги з теми "Unipore calcique mitochondrial"
1
Plovanich, Molly. The Molecular Characterization of the Mitochondrial Calcium Uniporter. 2014.
Знайти повний текст джерелаЧастини книг з теми "Unipore calcique mitochondrial"
1
Garg, Vivek, and Yuriy Y. Kirichok. "Patch-Clamp Analysis of the Mitochondrial Calcium Uniporter." In Calcium Signalling, 75–86. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4939-9018-4_7.
Повний текст джерела
2
Liu, Julia C., Randi J. Parks, Jie Liu, Justin Stares, Ilsa I. Rovira, Elizabeth Murphy, and Toren Finkel. "The In Vivo Biology of the Mitochondrial Calcium Uniporter." In Advances in Experimental Medicine and Biology, 49–63. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-55330-6_3.
Повний текст джерела
3
McCormack, James G., and Martin Crompton. "The Role and Study of Mammalian." In Cellular Calcium, 345–82. Oxford University PressOxford, 1991. http://dx.doi.org/10.1093/oso/9780199631315.003.0015.
Повний текст джерелаАнотація:
Abstract The inner membrane of mitochondria of mammalian, and perhaps of all vertebrate, tissues contains Ca2+ transport systems that mediate continuous Ca2+ cycling across the membrane (Figure I; see refs 1-3 for reviews). The cycle comprises a Ca2+ uniporter which allows passive Ca2+ entry down the Ca2+ electrochemical gradient and one, or possibly two, active egress mechanisms. The principal efflux mechanism involves obligatory exchange between Ca2+ and Na+ with the probable stoichiometry of 2Na+: 1Ca2\ this exchange is linked to the chemiosmotic H+ circuit via Na+:H+ exchange. Mitochondria may also contain a Na+-independent mechanism for Ca2+ efflux, although whether this involves direct Ca2+: H+ exchange is controversial. Although cycling of Ca2+involves the dissipation of the protonmotive gradient, under normal cellular conditions the calculated overall energy cost is less than 1% of the respiratory capacity of the mitochondria (1, 2).
4
Balderas, Enrique, Salah Sommakia, David Eberhardt, Sandra Lee, and Dipayan Chaudhuri. "The structural era of the mitochondrial calcium uniporter." In Calcium Signals, 12–1. IOP Publishing, 2023. http://dx.doi.org/10.1088/978-0-7503-2009-2ch12.
Повний текст джерелаТези доповідей конференцій з теми "Unipore calcique mitochondrial"
1
Shehwar, D., A. Aliotta, S. Barki, DB Calderara, L. Veuthey, CP Portela, R. M. Alam, and L. Alberio. "The role of Mitochondrial Calcium Uniporter in platelet signalling." In GTH Congress 2023 – 67th Annual Meeting of the Society of Thrombosis and Haemostasis Research – The patient as a benchmark. Georg Thieme Verlag, 2023. http://dx.doi.org/10.1055/s-0042-1760599.
Повний текст джерела
2
Zhang, Xinyan, Ryan J. Pachucki, Chelsea Corradetti, John Elrod, Stefania Gallucci, and Roberto Caricchio. "1013 The role of mitochondrial calcium uniporter (MCU) in lupus." In Lupus 21st Century 2023 Abstracts, September 27–30, Naples, Florida. Lupus Foundation of America, 2024. http://dx.doi.org/10.1136/lupus-2023-lupus21century.78.
Повний текст джерела
3
Gu, L., J. L. Casey, D. Davis, J. Kang, and A. B. B. Carter. "Bcl-2 Regulation by the Mitochondrial Calcium Uniporter Modulates Pulmonary Fibrosis." In American Thoracic Society 2020 International Conference, May 15-20, 2020 - Philadelphia, PA. American Thoracic Society, 2020. http://dx.doi.org/10.1164/ajrccm-conference.2020.201.1_meetingabstracts.a7875.
Повний текст джерела
4
Wang, Xiuchao, Shengchen Lin, Jianwei Sun, Jiaxin Kang, Jihui Hao, and Shengyu Yang. "Abstract 2776: Mitochondrial calcium uniporter in pancreatic cancer metastasis and metabolic stress resistance." In Proceedings: AACR Annual Meeting 2019; March 29-April 3, 2019; Atlanta, GA. American Association for Cancer Research, 2019. http://dx.doi.org/10.1158/1538-7445.sabcs18-2776.
Повний текст джерела
5
Wang, Xiuchao, Shengchen Lin, Jianwei Sun, Jiaxin Kang, Jihui Hao, and Shengyu Yang. "Abstract 2776: Mitochondrial calcium uniporter in pancreatic cancer metastasis and metabolic stress resistance." In Proceedings: AACR Annual Meeting 2019; March 29-April 3, 2019; Atlanta, GA. American Association for Cancer Research, 2019. http://dx.doi.org/10.1158/1538-7445.am2019-2776.
Повний текст джерела
6
Weissenrieder, Jillian S., Jason R. Pitarresi, Emily Fernandez-Garcia, Ben Z. Stanger, Anil K. Rustgi, and J. Kevin Foskett. "Abstract PO-026: The mitochondrial calcium uniporter contributes to PDAC development and invasion." In Abstracts: AACR Virtual Special Conference on Pancreatic Cancer; September 29-30, 2020. American Association for Cancer Research, 2020. http://dx.doi.org/10.1158/1538-7445.panca20-po-026.
Повний текст джерела
7
Shehwar, D., A. Aliotta, S. Barki, D. Bertaggia Calderara, L. Veuthey, C. Pereira Portela, M. Rizwam Alam, and L. Alberio. "Mitochondrial calcium uniporter as a Key Regulator in the Generation of Procoagulant COAT Platelets." In GTH Congress 2024 – 68th Annual Meeting of the Society of Thrombosis and Haemostasis Research – Building Bridges in Coagulation. Georg Thieme Verlag, 2024. http://dx.doi.org/10.1055/s-0044-1779176.
Повний текст джерела
8
Islam, M. N., G. A. Gusarova, S. Das, and J. Bhattacharya. "The Mitochondrial Calcium Uniporter of Pulmonary Type 2 Cells Determines Severity of Acute Lung Injury." In American Thoracic Society 2023 International Conference, May 19-24, 2023 - Washington, DC. American Thoracic Society, 2023. http://dx.doi.org/10.1164/ajrccm-conference.2023.207.1_meetingabstracts.a1243.
Повний текст джерела
9
Laura Dias Ramos, Ana, Natália Caroline Costa Coelho, Marcia Aparecida Silva Graminha, and Eduardo Maffud Cilli. "PEPTÍDEOS ANTILEISHMANIAIS: PLANEJAMENTO, SÍNTESE E CARACTERIZAÇÃO QUÍMICA DE NOVOS PEPTÍDEOS SINTÉTICOS DIRECIONADOS PARA O ALVO MOLECULAR MCU (MITOCHONDRIAL CALCIUM UNIPORTER) DE LEISHMANIA." In XI Congresso Farmacêutico e VII Jornada de Engenharia de Bioprocessos e Biotecnologia. Rio Grande do Sul: Softaliza Tecnologias LTDA, 2023. http://dx.doi.org/10.55592/jfunesp.2023.8315966.
Повний текст джерела