Dissertations / Theses on the topic 'Mitochondriopathie'

Beside its apoptotic function, the Apoptosis Inducing Factor (AIF), a highly conserved mitochondrial flavoprotein, plays a pro-vital role in eukaryotic cells through its interaction with CHCHD4, a mitochondrial protein that contributes to oxidative folding of respiratory complexes’ subunits. A unique feature of AIF is the ability to form a tight, air-stable charge-transfer complex (CT complex) upon reaction with NAD(H), which leads to protein dimerization modulating the affinity for its ligands. To date, nine point mutations of the human AIF gene were found to cause rare and severe neurodegenerative mitochondriopathies. To define the molecular bases of the pathogenicity of AIF variants, we selected a set of AIF mutations (G337E, D236G, G261S and F133L) and investigated their effects on both AIF molecular properties and its interaction with CHCHD4. To this aim, a combination of biophysical techniques, Microscale Thermophoresis (MST) and structural biology was used. AIF variants CT complex stability was evaluated studying its reoxidation by O2. Interestingly, CT complex of G337E and G261S forms displayed a faster oxidation compared to wild type AIF, indicating a lower stability. Moreover, the 3D structures of the CT complex of AIF-D236G and of AIF-F133L both in oxidized and CT complex state were obtained, showing, however, no significant structural rearrangements with respect to the wild type protein. Hence, we investigated possible alterations of the interaction with CHCHD4 induced by AIF pathogenic mutations. Through a MST approach, for the first time we quantitatively studied redox-dependent effects of AIF amino acid replacements on its affinity for CHCHD4, revealing a possible involvement of the G337 residue in protein-protein complex formation. We characterized the AIF-CHCHD4 complex also from a structural point of view using the Small-Angle X-ray Scattering (SAXS) technique, through which we identified a putative interaction region between the two proteins. In addition, all SAXS models obtained revealed that the solvent-exposed G337 residue is localized in the neighborhood of the identified region, in agreement with a possible role of this residue in complex formation. Our results, not only shed new light on AIF-CHCHD4 relationship, but also provide a possible explanation of the pathogenicity of the AIF G337E allelic variant.

Idiopathische Myositiden stellen die größte Gruppe der erworbenen Myopathien im Erwachsenenalter dar. Die Pathogenese dieser Erkrankungen ist sehr heterogen und nicht in allen Einzelheiten geklärt. Das Auftreten von mitochondrialen Veränderungen und mtDNADeletionen in idiopathischen Myositiden und deren pathophysiologische Bedeutung ist in der Literatur ein kontrovers diskutiertes Thema. Nach der Präsentation des bekannten Wissens über diese Erkrankungen wird in vorliegender Arbeit dieses Thema anhand lichtmikroskopischer Methoden unter Anwendung histologischer Spezialmethoden an Muskelbiopsien von 98 Patienten untersucht. Ziel der Arbeit ist es, mit verschiedenen histologischen Färbemethoden Hinweise für Mitochondrien-Alterationen und feinstrukturelle Charakteristika von primären Mitochondrialen Myopathien in idiopathischen Myositiden zu detektieren. Ein besonderer Schwerpunkt liegt auf der Anwendung einer neuen immunhistochemischen Methode unter Anwendung eines monoklonalen antimitochondrialen Antikörpers. Es wird der Fall eines Mädchens mit muskeldystrophischer Symptomatik dargestellt, dessen Muskelbiopsie im Alter von 7 Jahren die myohistologische Diagnose einer juvenilen Dermatomyositis und Hinweise auf eine mitochondriale Dysfunktion ergab. Die Ergebnisse der immunhistochemischen Methode korrelieren gut mit anderen bekannten mitochondrialen Färbungen, sind sensitiver und stellen möglicherweise eine gute Ergänzung zu den bekannten mitochondrialen Markern und Färbungen dar. Die beobachteten mitochondrialen Dysfunktionen sprechen für die gestörte Mitochondrienfunktion und eine früh im Krankheitsverlauf, am ehesten sekundäre, Beteiligung der Mitochondrien im Krankheitsprozess dieser primär nicht mitochondrialen Erkrankungen

Mitochondrien haben eine entscheidende Rolle im Zellmetabolismus, da sie den Hauptort der ATP-Produktion darstellen. Störungen des mitochondrialen Metabolismus sind mit einem weiten Spektrum von Erkrankungen assoziiert. Das Gehirn und die Muskulatur sind aufgrund ihres hohen Energiebedarfs dabei oft betroffen (Epilepsie, Ataxie, Myopathie). Diese Arbeit beschreibt die Klonierung von nukleären Genen des Komplexes I der mitochondrialen Atmungskette. Besonderes Augenmerk wird dabei auf die 51 kDa Untereinheit (NDUFV1) gerichtet, da sie mit ihrer Bindungsstelle für NADH2 die Eintrittspforte in den Komplex I darstellt. In dieser Untereinheit werden die ersten Mutationen beschrieben, die bei Kindern zu schwerer Entwicklungsretardierung, Leukenzephalopathie und Muskelhypotonie führen. Im weiteren werden Patienten mit isoliertem Komplex III Mangel molekulargenetisch untersucht und klassifiziert. Bei einem Patienten war ein isolierter Komplex III-Mangel und eine Mutation im mitochondrialen Cytochrom b-Gen mit einer septo-optischen Dysplasie vergesellschaftet. Am Ende beschreibt die Arbeit die Probleme der pränatalen Diagnostik mitochondrialer Erkrankungen und die Besonderheiten der genetischen Beratung betroffener Familien.
Mitochondria have a crucial role in the energy metabolism of the cell, since they constitute the main place for ATP-production. Defects in the mitochondrial metabolism are associated with a wide spectrum of diseases. Due to their high energy demand brain and muscles are regularly affected (epilepsy, ataxia, myopathy). This work describes the cloning of nuclear encoded genes of complex I of the mitochondrial respiratory chain. The main interest is directed towards the 51 kDa subunit (NDUFV1) since, due to its NADH2-binding domain, it constitutes the entry port into complex I. Therein the first mutations are described, which lead to severe developmental delay, leukencephalopathy and muscular hypotonia in infants. Additionally patients with isolated complex III-deficiency are examined molecularly and are classified according to their clinical symptoms. In one patient isolated complex III deficiency and a mutation in the mitochondrial cytochrome b-gene are associated with septo-optic dysplasia. At the end problems with prenatal diagnosis of mitochondrial diseases and the peculiarities of genetic counselling of affected families are discussed.

A dor associada ao câncer pode ser causada não somente pelos efeitos diretos ou indiretos da patologia primária, mas também pelo tratamento quimioterápico. A Cisplatina é um dos medicamentos anti-neoplásicos mais efetivos e mais comumente usados no tratamento de tumores sólidos. Entretanto, um de seus principais efeitos colaterais é a neurotoxicidade periférica. Os mecanismos celulares e moleculares da dor crônica induzida por quimioterápico são ainda bastante obscuros. Investigamos o papel da proteína quinase dependente de RNA (PKR) nos diferentes mecanismos neurobiológicos associados à dor crônica induzida pelo quimioterápico Cisplatina. O presente estudo avaliou: (1) O desenvolvimento de alodínia mecânica e hipernocicepção térmica em camundongos PKR-/- e PKR+/+ submetidos à administração do quimioterápico Cisplatina; (2) O estado de fosforilação das MAPKs (Erk1,2, p38 e JNK/SAP) e o fator de transcrição STAT-3 nas células do gânglio da raiz dorsal de animais tratados com Cisplatina; (3) Alterações na resistência e força muscular dos camundongos PKR-/- e PKR+/+ submetidos a administração do quimioterápico Cisplatina; (4) A proteólise muscular em músculos EDL (glicolíticos) e soleus (oxidativos) de camundongos PKR-/- e PKR+/+ após tratamento com Cisplatina (5) A síntese proteica através de Western Blot das proteínas Akt, FoxO 1 e FoxO 4, S6k1 e a S6 em células C2C12 analisando temporalmente o efeito da Cisplatina (6h, 12h e 24h); (6) O estresse oxidativo mitocondrial em células do gânglio da raiz dorsal e do músculo Soleus de camundongos PKR-/- e PKR+/+ após tratamento com Cisplatina. Os resultados obtidos foram: (1) Que com o tratamento com cisplatina produziu hipernocicepção térmica e alodínia mecânica nos animais PKR+/+; (2) A reduz da fosforilação do p38 não justifica o quadro de hipernocicepção e a hipernocicepção pode ocorrer a partir do aumento da fosforilação de STAT 3; (3) Animais que não tem a PKR são menos vulneráveis à ação deletéria da cisplatina sobre o músculo pois todos os testes comportamentais para atividade motora; (4) Não houve diferença na proteólise total mas sim na síntese proteica em animais PKR tratados com cisplatina; (5) Há alteração na via Akt quando analisa temporalmente a ação da cisplatina; (6) animais PKR -/- apresentaram índices mais altos da respiração mitocondrial comparados aos PKR +/+. Este estudo combinou métodos de biologia celular e molecular com paradigmas comportamentais a fim de investigar os possíveis mecanismos de ação da PKR no desenvolvimento de hipersensibilidade sensorial após o tratamento com quimioterápico. Os resultados deste trabalho devem evidenciar novos mecanismos neurobiológicos que contribuam para o entendimento da fisiopatologia da dor crônica de origem neurotóxica e apontar novas estratégias terapêuticas para o tratamento da dor crônica causada por quimioterapia
Pain associated with cancer can be caused by only direct or indirect products of the primary pathology, but also by chemotherapeutic treatment. Cisplatin is one of the most effective and most common anti-neoplastic drugs without the treatment of solid tumors. However, one of its major side effects is peripheral neurotoxicity. The cellular and molecular mechanisms of chronic pain induced by chemotherapy are still rather obscure. Investigators of role of RNA-dependent protein kinase (PKR) in the different neurobiological mechanisms associated with chronic pain induced by the chemotherapeutic Cisplatin. The present study evaluated: (1) the development of mechanical allodynia and thermal hypernociception in mice PKR - / - and PKR + / + submitted to chemotherapy Cisplatin; (2) The state of phosphorylation of the MAPKs (Erk1,2, p38 and JNK / SAP) and the transcription factor STAT-3 in the cells dorsal root ganglion of Cisplatin-treated animals; (3) Changes in muscle strength and strength of mice PKR - / - and PKR + / + submitted to the administration of the chemotherapeutic Cisplatin; (4) Muscle protein in EDL (glycolytic) and soleus (oxidative) muscles of mice PKR - / - and PKR + / + after treatment with Cisplatin (5) Western Blot Synthesis Protein of Akt, FoxO 1 and FoxO 4 S6k1 proteins and S6 in C2C12 cells by temporarily analyzing the effect of Cisplatin (6h, 12h and 24h); (6) Mitochondrial oxidative stress in dorsal root ganglion and Soleil muscle cells of PKR - / - and PKR + / + mice after treatment with Cisplatin. The results obtained were: (1) That with the treatment with cisplatin produced thermal hypernociception and mechanical allodynia in the animals PKR + / +; (2) The reduced phosphorylation of p38 does not justify the hyperencouragement and hypernociception can occur from increased STAT 3 phosphorylation; (3) Animals that do not have a PKR are less vulnerable to the deleterious action of cisplatin on muscle for all behavioral tests for motor activities; (4) There was no difference in total proteolysis but in protein synthesis in PKR animals treated with cisplatin; (5) There is alteration in the Akt pathway when the action of cisplatin is temporarily analyzed; (6) Animals PKR - / - had higher mitochondrial respiration rates compared to PKR + / +. This study combined methods of cellular and molecular biology with behavioral paradigms to investigate the possible mechanisms of action of PKR in the development of sensory hypersensitivity after treatment with chemotherapy. The results of this program are mandatory, which are responsible for the development of medicines for health and human health

Eight carriers of the A3243G mutation of mitochondrial DNA without stroke-like episodes were monitored for up to 7 years in clinical and metabolic studies, by magnetic resonance imaging (MRI) and positron emission tomography (PET). None developed mitochondrial encephalopathy (MELAS), but 2 developed diabetes mellitus, 1 terminal kidney failure and 2 cardiomyopathy. One patient improved markedly under ubiquinone. Electroencephalography showed progressive slowing in 2 cases, but electrophysiological tests and MRI were otherwise noncontributary. PET showed widespread cortical and basal ganglion metabolic deficits in 6 cases. We conclude that internal medical complications are more common than MELAS in adult carriers of the mutation. PET findings, firstly reported in such patients, suggest that chronic subclinical encephalopathy is very frequent, and PET may play a role in monitoring in the future
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich

Eight carriers of the A3243G mutation of mitochondrial DNA without stroke-like episodes were monitored for up to 7 years in clinical and metabolic studies, by magnetic resonance imaging (MRI) and positron emission tomography (PET). None developed mitochondrial encephalopathy (MELAS), but 2 developed diabetes mellitus, 1 terminal kidney failure and 2 cardiomyopathy. One patient improved markedly under ubiquinone. Electroencephalography showed progressive slowing in 2 cases, but electrophysiological tests and MRI were otherwise noncontributary. PET showed widespread cortical and basal ganglion metabolic deficits in 6 cases. We conclude that internal medical complications are more common than MELAS in adult carriers of the mutation. PET findings, firstly reported in such patients, suggest that chronic subclinical encephalopathy is very frequent, and PET may play a role in monitoring in the future.
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

La cachexie cancéreuse est un syndrome multifactoriel caractérisé notamment par une perte progressive du muscle squelettique, qui entraîne une diminution de la qualité de vie, de la réponse aux traitements anticancéreux, et de la survie des patients. De par la complexité physiopathologique de ce syndrome clinique, il n’existe pour le moment aucun traitement curatif.Malgré de récentes découvertes, les mécanismes à l’origine de la fonte musculaire squelettique ne sont pas clairement élucidés. Les résultats des études précliniques et cliniques pointent sur de possibles altérations des métabolismes mitochondrial et lipidique. De plus, si la composition corporelle est affectée par la tumeur, elle l’est aussi par les traitements anti-cancéreux.Au cours de ce travail de thèse, nous nous sommes donnés comme objectifs d’étudier les liens entre la composition corporelle et un traitement par chimiothérapie à base de bévacizumab (étude clinique STIC-Avastin (NCT00489697)) ; ou avec la structure et le métabolisme du muscle squelettique, dans le contexte de la cachexie cancéreuse (protocoles cliniques METERMUCADIG (NCT02573974) et METERMUS-IMC (NCT03027479))
Cancer cachexia is a multifactorial syndrome characterized by progressive loss of skeletal muscle, leading to decreased quality of life, response to cancer treatments, and patient survival. Due to the physio pathological complexity of this clinical syndrome, there is currently no cure to cancer cachexia.Despite recent discoveries, the mechanisms underlying skeletal muscle wasting are not clearly understood. Recent preclinical and clinical studies highlighted possible alterations in mitochondrial and lipid metabolism. Furthermore, body composition could be affected not only by the tumor, but also by anti-cancer treatments.During this PhD, the aims were to study the links between body composition and bevacizumab-based chemotherapy treatment (clinical study STIC-Avastin (NCT00489697)); or with skeletal muscle structure and metabolism, in the context of cancer cachexia (clinical protocols METERMUCADIG (NCT02573974) and METERMUS-IMC (NCT03027479))

Idiopathische Myositiden stellen die größte Gruppe der erworbenen Myopathien im Erwachsenenalter dar. Die Pathogenese dieser Erkrankungen ist sehr heterogen und nicht in allen Einzelheiten geklärt. Das Auftreten von mitochondrialen Veränderungen und mtDNADeletionen in idiopathischen Myositiden und deren pathophysiologische Bedeutung ist in der Literatur ein kontrovers diskutiertes Thema. Nach der Präsentation des bekannten Wissens über diese Erkrankungen wird in vorliegender Arbeit dieses Thema anhand lichtmikroskopischer Methoden unter Anwendung histologischer Spezialmethoden an Muskelbiopsien von 98 Patienten untersucht. Ziel der Arbeit ist es, mit verschiedenen histologischen Färbemethoden Hinweise für Mitochondrien-Alterationen und feinstrukturelle Charakteristika von primären Mitochondrialen Myopathien in idiopathischen Myositiden zu detektieren. Ein besonderer Schwerpunkt liegt auf der Anwendung einer neuen immunhistochemischen Methode unter Anwendung eines monoklonalen antimitochondrialen Antikörpers. Es wird der Fall eines Mädchens mit muskeldystrophischer Symptomatik dargestellt, dessen Muskelbiopsie im Alter von 7 Jahren die myohistologische Diagnose einer juvenilen Dermatomyositis und Hinweise auf eine mitochondriale Dysfunktion ergab. Die Ergebnisse der immunhistochemischen Methode korrelieren gut mit anderen bekannten mitochondrialen Färbungen, sind sensitiver und stellen möglicherweise eine gute Ergänzung zu den bekannten mitochondrialen Markern und Färbungen dar. Die beobachteten mitochondrialen Dysfunktionen sprechen für die gestörte Mitochondrienfunktion und eine früh im Krankheitsverlauf, am ehesten sekundäre, Beteiligung der Mitochondrien im Krankheitsprozess dieser primär nicht mitochondrialen Erkrankungen:INHALTSVERZEICHNIS ............................................................................................. I Abkürzungsverzeichnis .......................................................................................................................................iii 1 EINLEITUNG....................................................................................................... 1 1.1 Einführung ...................................................................................................................................................... 1 1.2 Aufbau und Funktion der Skelettmuskulatur............................................................................................... 1 1.3 Die Mitochondrien.......................................................................................................................................... 6 1.4 Erkrankungen der Skelettmuskulatur......................................................................................................... 11 1.4.1 Diagnostik der Skelettmuskelerkrankungen............................................................................................. 11 1.4.2 Entzündliche Muskelerkrankungen.......................................................................................................... 13 1.4.2.1 Polymyositis.................................................................................................................................... 15 1.4.2.2 Dermatomyositis .............................................................................................................................. 18 1.4.2.3 Einschlusskörpermyositis................................................................................................................ 21 1.4.3 Mitochondriale Myopathien..................................................................................................................... 23 1.5 Die Muskelbiopsie......................................................................................................................................... 26 1.6 Die Lichtmikroskopie der Skelettmuskulatur ............................................................................................. 28 1.6.1. Die Enzymhistochemie ........................................................................................................................... 28 1.6.2. Grundlagen der Immunhistochemie ........................................................................................................ 31 1.7 Die Elektronenmikroskopie .......................................................................................................................... 35 2 MATERIAL UND METHODEN .......................................................................... 36 2.1 Patienten........................................................................................................................................................ 36 2.1.1 Das Patientenkollektiv ............................................................................................................................. 36 2.1.2 Besonderer Fall einer Patientin mit juveniler Dermatomyositis............................................................... 38 2.2 Methoden....................................................................................................................................................... 44 2.2.1 Die Lichtmikroskopie .............................................................................................................................. 44 2.2.1.1 Enzymhistochemie ........................................................................................................................... 46 2.2.1.2 Immunhistochemie ........................................................................................................................... 49 2.2.2 Die Elektronenmikroskopie ..................................................................................................................... 54 2.3 Statistische Methoden .................................................................................................................................. 54 3 ERGEBNISSE ....................................................................................................... 56 3.1 Ergebnisse der Lichtmikroskopie................................................................................................................ 56 3.1.1 Ergebnisse der Enzymhistochemie........................................................................................................... 56 3.1.2 Ergebnisse der Immunhistochemie .......................................................................................................... 62 3.1.3 Korrelation der Ergebnisse der Enzymhistochemie und Immunhistochemie ........................................... 70 Inhaltsverzeichnis ii 3.2 Ergebnisse der Elektronenmikroskopie....................................................................................................... 73 4 DISKUSSION .................................................................................................... 76 4. 1 Lichtmikroskopie......................................................................................................................................... 76 4.1.1 Enzymhistochemie .................................................................................................................................. 76 4.1.1.1 Cytochrom-c-Oxidase ...................................................................................................................... 76 4.1.1.2 NADH............................................................................................................................................. 80 4.1.1.3 SDH ................................................................................................................................................ 80 4.1.1.4. Engel .............................................................................................................................................. 81 4.1.2 Immunhistochemie.................................................................................................................................. 84 4.2 Elektronenmikroskopie ................................................................................................................................ 89 4.3 Besonderer Fall einer Patientin mit juveniler Dermatomyositis ............................................................... 90 4.4 Effekte des Alterns auf die Mitochondrien und deren klinische Bedeutung ............................................ 93 4.5 Die Rolle der Mitochondrien in der Pathogenese der entzündlichen Muskelerkrankungen .................. 94 5 ZUSAMMENFASSUNG..................................................................................... 98 6 QUELLENANGABEN...................................................................................... 102 6.1 Literaturverzeichnis........................................................................................................................... 102 6.2 Abbildungsverzeichnis ............................................................................................................................... 109 6.3 Tabellenverzeichnis .................................................................................................................................... 110 7 DANKSAGUNG................................................................................................... 111 8 LEBENSLAUF..................................................................................................... 112 9 ERKLÄRUNG ÜBER DIE EIGENSTÄNDIGE ABFASSUNG DER ARBEIT ... 113