scholarly journals Palmitic Acid, but Not Lauric Acid, Induces Metabolic Inflammation, Mitochondrial Fragmentation, and a Drop in Mitochondrial Membrane Potential in Human Primary Myotubes

2021 ◽  
Vol 8 ◽  
Author(s):  
Domenico Sergi ◽  
Natalie Luscombe-Marsh ◽  
Nenad Naumovski ◽  
Mahinda Abeywardena ◽  
Nathan O'Callaghan
Keyword(s):  
Insulin Resistance ◽  
Membrane Potential ◽  
Electron Transport ◽  
Mitochondrial Membrane Potential ◽  
Electron Transport Chain ◽  
Mitochondrial Membrane ◽  
Chain Complex ◽  
Mitochondrial Fragmentation ◽  
Metabolic Inflammation ◽  
Transport Chain

The chain length of saturated fatty acids may dictate their impact on inflammation and mitochondrial dysfunction, two pivotal players in the pathogenesis of insulin resistance. However, these paradigms have only been investigated in animal models and cell lines so far. Thus, the aim of this study was to compare the effect of palmitic (PA) (16:0) and lauric (LA) (12:0) acid on human primary myotubes mitochondrial health and metabolic inflammation. Human primary myotubes were challenged with either PA or LA (500 μM). After 24 h, the expression of interleukin 6 (IL-6) was assessed by quantitative polymerase chain reaction (PCR), whereas Western blot was used to quantify the abundance of the inhibitor of nuclear factor κB (IκBα), electron transport chain complex proteins and mitofusin-2 (MFN-2). Mitochondrial membrane potential and dynamics were evaluated using tetraethylbenzimidazolylcarbocyanine iodide (JC-1) and immunocytochemistry, respectively. PA, contrarily to LA, triggered an inflammatory response marked by the upregulation of IL-6 mRNA (11-fold; P < 0.01) and a decrease in IκBα (32%; P < 0.05). Furthermore, whereas PA and LA did not differently modulate the levels of mitochondrial electron transport chain complex proteins, PA induced mitochondrial fragmentation (37%; P < 0.001), decreased MFN-2 (38%; P < 0.05), and caused a drop in mitochondrial membrane potential (11%; P < 0.01) compared to control, with this effect being absent in LA-treated cells. Thus, LA, as opposed to PA, did not trigger pathogenetic mechanisms proposed to be linked with insulin resistance and therefore represents a healthier saturated fatty acid choice to potentially preserve skeletal muscle metabolic health.

scholarly journals Bcl-2 Family Members and Functional Electron Transport Chain Regulate Oxygen Deprivation-Induced Cell Death

2002 ◽  
Vol 22 (1) ◽  
pp. 94-104 ◽  
Author(s):  
David S. McClintock ◽  
Matthew T. Santore ◽  
Vivian Y. Lee ◽  
Joslyn Brunelle ◽  
G. R. Scott Budinger ◽  
...  
Keyword(s):  
Cell Death ◽  
Membrane Potential ◽  
Electron Transport ◽  
Mitochondrial Membrane Potential ◽  
Electron Transport Chain ◽  
Mitochondrial Membrane ◽  
Family Members ◽  
Oxygen Deprivation ◽  
Caspase 9 ◽  
Transport Chain

ABSTRACT The mechanisms underlying cell death during oxygen deprivation are unknown. We report here a model for oxygen deprivation-induced apoptosis. The death observed during oxygen deprivation involves a decrease in the mitochondrial membrane potential, followed by the release of cytochrome c and the activation of caspase-9. Bcl-XL prevented oxygen deprivation-induced cell death by inhibiting the release of cytochrome c and caspase-9 activation. The ability of Bcl-XL to prevent cell death was dependent on allowing the import of glycolytic ATP into the mitochondria to generate an inner mitochondrial membrane potential through the F1F0-ATP synthase. In contrast, although activated Akt has been shown to inhibit apoptosis induced by a variety of apoptotic stimuli, it did not prevent cell death during oxygen deprivation. In addition to Bcl-XL, cells devoid of mitochondrial DNA (ρ° cells) that lack a functional electron transport chain were resistant to oxygen deprivation. Further, murine embryonic fibroblasts from bax −/− bak −/− mice did not die in response to oxygen deprivation. These data suggest that when subjected to oxygen deprivation, cells die as a result of an inability to maintain a mitochondrial membrane potential through the import of glycolytic ATP. Proapoptotic Bcl-2 family members and a functional electron transport chain are required to initiate cell death in response to oxygen deprivation.

Cadmium Alters Mitochondrial Membrane Potential, Inhibits Electron Transport Chain Activity and Induces Callose Deposition in Rice Seedlings

2017 ◽  
Vol 37 (1) ◽  
pp. 335-344 ◽  
Author(s):  
Rajneesh Kumar Srivastava ◽  
Ritika Rajpoot ◽  
Poonam Pandey ◽  
Anjana Rani ◽  
R. S. Dubey
Keyword(s):  
Membrane Potential ◽  
Electron Transport ◽  
Mitochondrial Membrane Potential ◽  
Electron Transport Chain ◽  
Mitochondrial Membrane ◽  
Rice Seedlings ◽  
Callose Deposition ◽  
Transport Chain

scholarly journals AB0031 T HELPER 17 CELLS WERE SIGNIFICANTLY DECREASED BY MITOCHONDRIAL ELECTRON TRANSPORT CHAIN COMPLEX INHIBITOR IN PATIENTS WITH RHEUMATOID ARTHRITIS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1318.2-1318
Author(s):  
H. R. Lee ◽  
S. J. Yoo ◽  
J. Kim ◽  
I. S. Yoo ◽  
C. K. Park ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Electron Transport ◽  
Disease Activity ◽  
Th17 Cells ◽  
Electron Transport Chain ◽  
Chain Complex ◽  
Complex Iii ◽  
Mitochondrial Electron Transport Chain ◽  
Transport Chain ◽  
Healthy Control

Background:Reactive oxygen species (ROS) and T helper 17 (TH17) cells have been known to play an important role in the pathogenesis of rheumatoid arthritis (RA). However, the interrelationship between ROS and TH17 remains unclear in RAObjectives:To explore whether ROS affect TH17 cells in peripheral blood mononuclear cells (PBMC) of RA patients, we analyzed ROS expressions among T cell subsets following treatment with mitochondrial electron transport chain complex inhibitors.Methods:Blood samples were collected from 40 RA patients and 10 healthy adult volunteers. RA activity was divided according to clinical parameter DAS28. PBMC cells were obtained from the whole blood using lymphocyte separation medium density gradient centrifugation. Following PBMC was stained with Live/Dead stain dye, cells were incubated with antibodies for CD3, CD4, CD8, and CD25. After fixation and permeabilization, samples were stained with antibodies for FoxP3 and IL-17A. MitoSox were used for mitochondrial specific staining.Results:The frequency of TH17 cells was increased by 4.83 folds in moderate disease activity group (5.1>DAS28≥3.2) of RA patients compared to healthy control. Moderate RA activity patients also showed higher ratio of TH17/Treg than healthy control (3.57 folds). All RA patients had elevated expression of mitochondrial specific ROS than healthy control. When PBMC cells were treated with 2.5uM of antimycin A (mitochondrial electron transport chain complex III inhibitor) for 16 h, the frequency of TH17 cells was significantly decreased.Conclusion:The mitochondrial electron transport chain complex III inhibitor markedly downregulated the frequency of TH17 cells in moderate disease activity patients with RA. These findings provide a novel approach to regulate TH17 function in RA through mitochondrial metabolism related ROS production.References:[1]Szekanecz, Z., et al., New insights in synovial angiogenesis. Joint Bone Spine, 2010. 77(1): p. 13-9.[2]Prevoo, M.L., et al., Modified disease activity scores that include twenty-eight-joint counts. Development and validation in a prospective longitudinal study of patients with rheumatoid arthritis. Arthritis Rheum, 1995. 38(1): p. 44-8.Disclosure of Interests:None declared

Anaerobic respiration sustains mitochondrial membrane potential in a prolyl hydroxylase pathway-activated cancer cell line in a hypoxic microenvironment

2014 ◽  
Vol 306 (4) ◽  
pp. C334-C342 ◽  
Author(s):  
Eiji Takahashi ◽  
Michihiko Sato
Keyword(s):  
Membrane Potential ◽  
Electron Transport ◽  
Cell Line ◽  
Mitochondrial Membrane Potential ◽  
Cancer Cell ◽  
Mitochondrial Membrane ◽  
Cancer Cell Line ◽  
Prolyl Hydroxylase ◽  
Complex Ii ◽  
Pathway Activation

To elucidate how tumor cells produce energy in oxygen-depleted microenvironments, we studied the possibility of mitochondrial electron transport without oxygen. We produced well-controlled oxygen gradients (ΔO2) in monolayer-cultured cells. We then visualized oxygen levels and mitochondrial membrane potential (ΔΦm) in individual cells by using the red shift of green fluorescent protein (GFP) fluorescence and a cationic fluorescent dye, respectively. In this two-dimensional tissue model, ΔΦm was abolished in cells >500 μm from the oxygen source [the anoxic front (AF)], indicating limitations in diffusional oxygen delivery. This result perfectly matched GFP-determined ΔO2. In cells pretreated with dimethyloxaloylglycine (DMOG), a prolyl hydroxylase domain-containing protein (PHD) inhibitor, the AF was expanded to 1,500–2,000 μm from the source. In these cells, tissue ΔO2 was substantially decreased, indicating that PHD pathway activation suppressed mitochondrial respiration. The expansion of the AF and the reduction of ΔO2 were much more prominent in a cancer cell line (Hep3B) than in the equivalent fibroblast-like cell line (COS-7). Hence, the results indicate that PHD pathway-activated cells can sustain ΔΦm, despite significantly decreased electron flux to complex IV. Complex II inhibition abolished the effect of DMOG in expanding the AF, although tissue ΔO2 remained shallow. Separate experiments demonstrated that complex II plays a substantial role in sustaining ΔΦm in DMOG-pretreated Hep3B cells with complex III inhibition. From these results, we conclude that PHD pathway activation can sustain ΔΦm in an otherwise anoxic microenvironment by decreasing tissue ΔO2 while activating oxygen-independent electron transport in mitochondria.

Reduced electron transport chain complex I protein abundance and function in Mfn2‐deficient myogenic progenitors lead to oxidative stress and mitochondria swelling

2021 ◽  
Vol 35 (4) ◽  
Author(s):  
Nanjian Luo ◽  
Feng Yue ◽  
Zhihao Jia ◽  
Jingjuan Chen ◽  
Qing Deng ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Electron Transport ◽  
Complex I ◽  
Electron Transport Chain ◽  
Chain Complex ◽  
Protein Abundance ◽  
Transport Chain ◽  
And Function
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