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.

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.

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

Anoxia-induced apoptosis occurs through a mitochondria-dependent pathway in lung epithelial cells

2002 ◽  
Vol 282 (4) ◽  
pp. L727-L734 ◽  
Author(s):  
Matthew T. Santore ◽  
David S. McClintock ◽  
Vivian Y. Lee ◽  
G. R. Scott Budinger ◽  
Navdeep S. Chandel
Keyword(s):  
Cell Death ◽  
Electron Transport ◽  
Cytochrome C ◽  
Electron Transport Chain ◽  
A549 Cells ◽  
Lung Epithelial Cells ◽  
Caspase 9 ◽  
Transport Chain ◽  
Lung Epithelial ◽  
Induced Apoptosis

The intracellular signaling pathways that control O2 deprivation (anoxia)-induced apoptosis have not been fully defined in lung epithelial cells. We show here that the lung epithelial cell line A549 releases cytochrome c and activates caspase-9 followed by DNA fragmentation and plasma membrane breakage in response to anoxia. The antiapoptotic protein Bcl-XL prevented the anoxia-induced cell death by inhibiting the release of cytochrome c and caspase-9 activation. A549 cells devoid of mitochondrial DNA (ρ°-cells) and lacking a functional electron transport chain were resistant to anoxia-induced apoptosis. A549 cells preconditioned with either hypoxia (1.5% O2) or tumor necrosis factor-α, which activated the transcription factors hypoxia-inducible factor-1 or nuclear factor-κB, respectively, did not provide protection from anoxia-induced cell death. These results indicate that A549 cells require a functional electron transport chain and the release of cytochrome c for anoxia-induced apoptosis.

scholarly journals Loss of Mcl-1 Protein and Inhibition of Electron Transport Chain Together Induce Anoxic Cell Death

2006 ◽  
Vol 27 (4) ◽  
pp. 1222-1235 ◽  
Author(s):  
Joslyn K. Brunelle ◽  
Emelyn H. Shroff ◽  
Harris Perlman ◽  
Andreas Strasser ◽  
Carlos T. Moraes ◽  
...  
Keyword(s):  
Cell Death ◽  
Mitochondrial Dna ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Hypoxia Inducible Factor ◽  
Caspase 9 ◽  
Transport Chain ◽  
Base Pair Deletion ◽  
Caspase 2 ◽  
The Individual

ABSTRACT How cells die in the absence of oxygen (anoxia) is not understood. Here we report that cells deficient in Bax and Bak or caspase-9 do not undergo anoxia-induced cell death. However, the caspase-9 null cells do not survive reoxygenation due to the generation of mitochondrial reactive oxygen species. The individual loss of Bim, Bid, Puma, Noxa, Bad, caspase-2, or hypoxia-inducible factor 1β, which are potential upstream regulators of Bax or Bak, did not prevent anoxia-induced cell death. Anoxia triggered the loss of the Mcl-1 protein upstream of Bax/Bak activation. Cells containing a mitochondrial DNA cytochrome b 4-base-pair deletion ([rho −] cells) and cells depleted of their entire mitochondrial DNA ([rho 0] cells) are oxidative phosphorylation incompetent and displayed loss of the Mcl-1 protein under anoxia. [rho 0] cells, in contrast to [rho −] cells, did not die under anoxia. However, [rho 0] cells did undergo cell death in the presence of the Bad BH3 peptide, an inhibitor of Bcl-XL/Bcl-2 proteins. These results indicate that [rho 0] cells survive under anoxia despite the loss of Mcl-1 protein due to residual prosurvival activity of the Bcl-XL/Bcl-2 proteins. Collectively, these results demonstrate that anoxia-induced cell death requires the loss of Mcl-1 protein and inhibition of the electron transport chain to negate Bcl-XL/Bcl-2 proteins.

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.

Abstract 371: Mitochondrial Antiviral Signaling (MAVS) Protects Cardiomyocytes Under Oxidative Stress by Interfering with Bax-Mediated Cell Death

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Toshitaka Yajima ◽  
Stanley Park ◽  
Hanbing Zhou ◽  
Michinari Nakamura ◽  
Mitsuyo Machida ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Membrane Potential ◽  
Cytochrome C ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Cytochrome C Release ◽  
Antiviral Signaling ◽  
Cell Death Pathway ◽  
The Impact

MAVS is a mitochondrial outer membrane protein that activates innate antiviral signaling by recognizing cytosolic viral RNAs and DNAs. While the discovery of MAVS is the first molecular evidence that links mitochondria to innate immune mechanisms, it is still unclear whether MAVS affects mitochondrial cell death as a member of caspase activation and recruitment domain (CARD)-containing proteins. We found that MAVS interacts with Bax through CARD by Yeast two-hybrid and a series of immunoprecipitation (IP) assay, which led us to hypothesize that MAVS functions not only in the innate antiviral mechanisms but also in the mitochondrial cell death pathway. Methods: 1) We examined molecular interaction between MAVS and Bax under oxidative stress by IP using isolated myocytes with H2O2 stimulation and the heart post ischemia-reperfusion (I/R). 2) We evaluated the effect of MAVS on mitochondrial membrane potential and apoptosis under H2O2 stimulation using isolated myocytes with adenoviral MAVS knockdown. 3) We investigated the impact of MAVS on %myocardial infarction (%MI) post I/R using cardiac-specific MAVS knockout (cKO) and transgenic (cTg) mice which we have originally generated. 4) We examined the effect of MAVS on recombinant Bax (rBax)-mediated cytochrome c release using isolated mitochondria from wild type (WT) and MAVS KO mice. Results: 1) The amount of Bax pulled down with MAVS was significantly increased in isolated myocytes with 0.2 mM H2O2 compared to those without stimulation (mean±SD; 1.808±0.14, n=5, p<0.001) and in the heart post I/R compared to sham (2.2±1.19, n=3, p=0.0081). 2) Myocytes with MAVS knockdown showed clear abnormalities in mitochondrial membrane potential and caspace-3 cleavage with 0.2 mM H2O2 compared to control cardiomyocytes. 3) MAVS cKO had significantly larger %MI than WT (81.9 ± 5.8% vs. 42.6 ± 13.6%, n=8, p=0.0008). In contrast, MAVS cTg had significantly smaller %MI that WT (30.0 ± 4.8% vs. 49.2 ± 4.8%, n=10, p=0.0113). 4) Mitochondria from MAVS KO exhibited cytochrome c release after incubation with 2.5 μ g of rBax while those from WT required 10 μ g of rBax. Conclusion: These results demonstrate that MAVS protects cardiomyocyte under oxidative stress by interfering with Bax-mediated cytochrome c release from mitochondria.

scholarly journals Protein Kinase Cδ Targets Mitochondria, Alters Mitochondrial Membrane Potential, and Induces Apoptosis in Normal and Neoplastic Keratinocytes When Overexpressed by an Adenoviral Vector

1999 ◽  
Vol 19 (12) ◽  
pp. 8547-8558 ◽  
Author(s):  
Luowei Li ◽  
Patricia S. Lorenzo ◽  
Krisztina Bogi ◽  
Peter M. Blumberg ◽  
Stuart H. Yuspa
Keyword(s):  
Cell Death ◽  
Membrane Potential ◽  
Protein Kinase ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Fluorescent Protein ◽  
Protein Fusion ◽  
Cell Death Pathway ◽  
Morphological Criteria ◽  
Protein Kinase Cδ

ABSTRACT Inactivation of protein kinase Cδ (PKCδ) is associated with resistance to terminal cell death in epidermal tumor cells, suggesting that activation of PKCδ in normal epidermis may be a component of a cell death pathway. To test this hypothesis, we constructed an adenovirus vector carrying an epitope-tagged PKCδ under a cytomegalovirus promoter to overexpress PKCδ in normal and neoplastic keratinocytes. While PKCδ overexpression was detected by immunoblotting in keratinocytes, the expression level of other PKC isozymes, including PKCα, PKCɛ, PKCζ, and PKCη, did not change. Calcium-independent PKC-specific kinase activity increased after infection of keratinocytes with the PKCδ adenovirus. Activation of PKCδ by 12-O-tetradecanoylphorbol-13-acetate (TPA) at a nanomolar concentration was lethal to normal and neoplastic mouse and human keratinocytes overexpressing PKCδ. Lethality was inhibited by PKC selective inhibitors, GF109203X and Ro-32-0432. TPA-induced cell death was apoptotic as evidenced by morphological criteria, TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling) assay, DNA fragmentation, and increased caspase activity. Subcellular fractionation indicated that PKCδ translocated to a mitochondrial enriched fraction after TPA activation, and this finding was confirmed by confocal microscopy of cells expressing a transfected PKCδ-green fluorescent protein fusion protein. Furthermore, activation of PKCδ in keratinocytes altered mitochondrial membrane potential, as indicated by rhodamine-123 fluorescence. Mitochondrial inhibitors, rotenone and antimycin A, reduced TPA-induced cell death in PKCδ-overexpressing keratinocytes. These results indicate that PKCδ can initiate a death pathway in keratinocytes that involves direct interaction with mitochondria and alterations of mitochondrial function.

Sign in / Sign up

Export Citation Format

Share Document