scholarly journals Global ischaemia induces a biphasic response of the mitochondrial respiratory chain. Anoxic pre-perfusion protects against ischaemic damage

1992 ◽  
Vol 281 (3) ◽  
pp. 709-715 ◽  
Author(s):  
K Veitch ◽  
A Hombroeckx ◽  
D Caucheteux ◽  
H Pouleur ◽  
L Hue
Keyword(s):  
Respiratory Chain ◽  
Complex I ◽  
Nadh Oxidase ◽  
Mitochondrial Respiratory Chain ◽  
Complex Iii ◽  
Biphasic Response ◽  
Ischaemic Damage ◽  
Global Ischaemia ◽  
Complex I Activity ◽  
Mitochondrial Respiratory

Studies of Langendorff-perfused rat hearts have revealed a biphasic response of the mitochondrial respiratory chain to global ischaemia. The initial effect is a 30-40% increase in the rate of glutamate/malate oxidation after 10 min of ischaemia, owing to an increase in the capacity for NADH oxidation. This effect is followed by a progressive decrease in these oxidative activities as the ischaemia is prolonged, apparently owing to damage to Complex I at a site subsequent to the NADH dehydrogenase component. This damage is exacerbated by reperfusion, which causes a further decrease in Complex I activity and also decreases the activities of the other complexes, most notably of Complex III. Perfusion for up to 1 h with anoxic buffer produced only the increase in NADH oxidase activity, and neither anoxia alone, nor anoxia and reperfusion, caused loss of Complex I activity. Perfusing for 3-10 min with anoxic buffer before 1 h of global ischaemia had a significant protective effect against the ischaemia-induced damage to Complex I.

scholarly journals Blood-based mitochondrial respiratory chain function in major depression

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Johan Fernström ◽  
Synthia H. Mellon ◽  
Marlon A. McGill ◽  
Martin Picard ◽  
Victor I. Reus ◽  
...  
Keyword(s):  
Respiratory Chain ◽  
Complex I ◽  
Mononuclear Cells ◽  
Rating Scale ◽  
Citrate Synthase ◽  
Mitochondrial Respiratory Chain ◽  
Mitochondrial Markers ◽  
Mitochondrial Dna Copy Number ◽  
Complex I Activity ◽  
Mitochondrial Respiratory

AbstractMitochondrial dysfunction has been implicated in major depressive disorder (MDD). A measure of mitochondrial respiratory chain (RC) enzymatic activity—the Mitochondrial Health Index (MHI)—has previously been found to correlate with stress and emotional states in caregivers. We here report mitochondrial RC activities, mitochondrial DNA copy number (mtDNAcn), and the composite MHI in unmedicated and somatically healthy subjects with MDD (n = 47) and healthy controls (HC) (n = 11). We also explore, in a subset of the MDD sample (n = 33), whether these markers are associated with response to 8 weeks of SSRI treatment. Mitochondrial RC complexes I, II, IV, citrate synthase (CS), mtDNAcn, and the MHI were assayed in peripheral blood mononuclear cells. Treatment response was defined as >50% decrease on the 25-item Hamilton Depression Rating Scale (HRDS-25). There were no significant differences in MHI or any of the mitochondrial markers between MDD subjects and HCs. Compared to SSRI nonresponders, SSRI responders had significantly higher baseline mitochondrial content markers CS (p = 0.02) and mtDNAcn (p = 0.02), and higher complex I activity (p = 0.01). Complex II activity increased significantly over treatment, irrespective of clinical response (p = 0.03). Complex I activity decreased in responders (n = 9), but increased in nonresponders (n = 18) (group x time interaction, p = 0.02). Absolute treatment-associated change in HDRS-25 scores correlated significantly with change in complex I activity between baseline and week 8 (r = 0.47, p = 0.01). Although mitochondrial markers did not distinguish MDD from controls, they did distinguish SSRI responders from nonresponders. If larger studies validate these mitochondrial differences, they may become useful biomarkers and identify new drug targets.

scholarly journals Specific requirements of nonbilayer phospholipids in mitochondrial respiratory chain function and formation

2016 ◽  
Vol 27 (14) ◽  
pp. 2161-2171 ◽  
Author(s):  
Charli D. Baker ◽  
Writoban Basu Ball ◽  
Erin N. Pryce ◽  
Vishal M. Gohil
Keyword(s):  
Respiratory Chain ◽  
Mitochondrial Membrane ◽  
Phospholipid Composition ◽  
Mitochondrial Respiratory Chain ◽  
Complex Iii ◽  
Specific Requirement ◽  
Transport Pathway ◽  
Contact Sites ◽  
Yeast Mutants ◽  
Mitochondrial Respiratory

Mitochondrial membrane phospholipid composition affects mitochondrial function by influencing the assembly of the mitochondrial respiratory chain (MRC) complexes into supercomplexes. For example, the loss of cardiolipin (CL), a signature non–bilayer-forming phospholipid of mitochondria, results in disruption of MRC supercomplexes. However, the functions of the most abundant mitochondrial phospholipids, bilayer-forming phosphatidylcholine (PC) and non–bilayer-forming phosphatidylethanolamine (PE), are not clearly defined. Using yeast mutants of PE and PC biosynthetic pathways, we show a specific requirement for mitochondrial PE in MRC complex III and IV activities but not for their formation, whereas loss of PC does not affect MRC function or formation. Unlike CL, mitochondrial PE or PC is not required for MRC supercomplex formation, emphasizing the specific requirement of CL in supercomplex assembly. Of interest, PE biosynthesized in the endoplasmic reticulum (ER) can functionally substitute for the lack of mitochondrial PE biosynthesis, suggesting the existence of PE transport pathway from ER to mitochondria. To understand the mechanism of PE transport, we disrupted ER–mitochondrial contact sites formed by the ERMES complex and found that, although not essential for PE transport, ERMES facilitates the efficient rescue of mitochondrial PE deficiency. Our work highlights specific roles of non–bilayer-forming phospholipids in MRC function and formation.

Succinimidyl oleate, established inhibitor of CD36/FAT translocase inhibits complex III of mitochondrial respiratory chain

2010 ◽  
Vol 391 (3) ◽  
pp. 1348-1351 ◽  
Author(s):  
Zdeněk Drahota ◽  
Marek Vrbacký ◽  
Hana Nůsková ◽  
Ludmila Kazdová ◽  
Václav Zídek ◽  
...  
Keyword(s):  
Respiratory Chain ◽  
Mitochondrial Respiratory Chain ◽  
Complex Iii ◽  
Mitochondrial Respiratory

scholarly journals Mitochondrial Respiratory Chain Protein Co-Regulation in the Human Brain

2021 ◽  
Author(s):  
Caroline Trumpff ◽  
Edward Owusu-Ansah ◽  
Hans-Ulrich Klein ◽  
Annie Lee ◽  
Vladislav Petyuk ◽  
...  
Keyword(s):  
Human Brain ◽  
Respiratory Chain ◽  
Complex I ◽  
Molecular Mechanisms ◽  
Nuclear Dna ◽  
Mitochondrial Protein ◽  
Mitochondrial Respiratory Chain ◽  
Mtdna Copy Number ◽  
Mt Dna ◽  
Mitochondrial Respiratory

Mitochondrial respiratory chain (RC) function requires the stochiometric interaction among dozens of proteins but their co-regulation has not been defined in the human brain. Here, using quantitative proteomics across three independent cohorts we systematically characterized the co-regulation patterns of mitochondrial RC proteins in the human dorsolateral prefrontal cortex (DLPFC). Whereas the abundance of RC protein subunits that physically assemble into stable complexes were correlated, indicating their co-regulation, RC assembly factors exhibited modest co-regulation. Within complex I, nuclear DNA-encoded subunits exhibited >2.5-times higher co-regulation than mitochondrial (mt)DNA-encoded subunits. Moreover, mtDNA copy number was unrelated to mtDNA-encoded subunits abundance, suggesting that mtDNA content is not limiting. Alzheimer disease (AD) brains exhibited reduced abundance of complex I RC subunits, an effect largely driven by a 2-4% overall lower mitochondrial protein content. These findings provide foundational knowledge to identify molecular mechanisms contributing to age- and disease-related erosion of mitochondrial function in the human brain.

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