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.

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 Glyoxal Damages Human Aortic Endothelial Cells by Perturbing the Glutathione, Mitochondrial Membrane Potential, and Mitogen-Activated Protein Kinase Pathways

2021 ◽  
Author(s):  
Ming-Zhang Xie ◽  
Chun Guo ◽  
Jia-Qi Dong. BA ◽  
Jie Zhang ◽  
Ke-Tao Sun ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Membrane Potential ◽  
Protein Kinase ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Mitogen Activated Protein Kinase ◽  
Aortic Endothelial Cells ◽  
Mitogen Activated Protein ◽  
Human Aortic Endothelial Cells ◽  
Quantitative Fluorescence

Abstract Background: Exposure to glyoxal, the smallest dialdehyde, is associated with several diseases; humans are routinely exposed to glyoxal because of its ubiquitous presence in foods and the environment. The aim of this study was to examine the damage caused by glyoxal in human aortic endothelial cells. Methods: Cell survival assays and quantitative fluorescence assays were performed to measure DNA damage; oxidative stress was detected by colorimetric assays and quantitative fluorescence, and the mitogen-activated protein kinase pathways were assessed using western blotting. Results: Exposure to glyoxal was found to be linked to abnormal glutathione activity, the collapse of mitochondrial membrane potential, and the activation of mitogen-activated protein kinase pathways. However, DNA damage and thioredoxin oxidation were not induced by dialdehydes. Conclusions: Intracellular glutathione, members of the mitogen-activated protein kinase pathways, and the mitochondrial membrane potential are all critical targets of glyoxal. These findings provide novel insights into the molecular mechanisms perturbed by glyoxal and may facilitate the development of new therapeutics and diagnostic markers for cardiovascular diseases.

scholarly journals Progesterone Maintains Basal Intracellular Adenosine Triphosphate Levels and Viability of Spontaneously Immortalized Granulosa Cells by Promoting an Interaction between 14-3-3σ and ATP Synthaseβ/Precursor through a Protein Kinase G-Dependent Mechanism

Endocrinology ◽  
2007 ◽  
Vol 148 (5) ◽  
pp. 2037-2044 ◽  
Author(s):  
John J. Peluso ◽  
Xiufang Liu ◽  
Jonathan Romak
Keyword(s):  
Membrane Potential ◽  
Protein Kinase ◽  
Mitochondrial Membrane Potential ◽  
Granulosa Cells ◽  
Mitochondrial Membrane ◽  
Apoptotic Cell ◽  
Protein Kinase G ◽  
Disulfonic Acid ◽  
Causative Role ◽  
Atp Content

The present studies were designed to 1) describe changes in both the mitochondrial membrane potential and ATP content of spontaneously immortalized granulosa cells as they undergo apoptosis, 2) identify some of the downstream events that are activated by progesterone (P4), and 3) relate these downstream events to changes in mitochondrial function and apoptotic cell death. These studies revealed that in response to serum deprivation, the mitochondrial membrane potential initially hyperpolarizes and ATP content increases. That this increase in ATP is required for apoptosis was demonstrated by the finding that oligomycin inhibited the increase in ATP and apoptosis. Piridoxalphosphate-6-azopeyl-2′-4′-disulfonic acid, an inhibitor of purinergic receptors, which are activated by ATP, also inhibited apoptosis due to serum withdrawal. This study provides additional support for ATP’s causative role in apoptosis. Moreover, 8-Br-cGMP, a protein kinase G (PKG) activator, mimicked P4’s action, whereas a PKG antagonist, DT-3, attenuated P4’s suppressive effect on ATP and apoptosis. Finally, DT-3 treatment was shown to attenuate P4-regulated phosphorylation of 14-3-3σ and its binding partner, ATP synthaseβ/precursor and the amount of ATP synthaseβ/precursor that bound to 14-3-3σ. Based on these data, it is proposed that P4 prevents apoptosis in part by activating PKG, which in turn maintains the interaction between ATP synthaseβ/precursor and 14-3-3σ. In the absence of P4-induced PKG activity, we further propose that some ATP synthaseβ precursor dissociates from 14-3-3σ, resulting in its activation and incorporation into the ATP synthase complex, which ultimately results in an increase in ATP and apoptosis.

scholarly journals The U95 Protein of Human Herpesvirus 6B Interacts with Human GRIM-19: Silencing of U95 Expression Reduces Viral Load and Abrogates Loss of Mitochondrial Membrane Potential

2007 ◽  
Vol 82 (2) ◽  
pp. 1011-1020 ◽  
Author(s):  
W. M. Yeo ◽  
Yuji Isegawa ◽  
Vincent T. K. Chow
Keyword(s):  
Cell Death ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Human Herpesvirus ◽  
Ultrastructural Changes ◽  
Gene Encoding ◽  
Interacting Protein ◽  
Functional Aspects ◽  
Infected Cells

ABSTRACT To better understand the pathogenesis of human herpesvirus 6 (HHV-6), it is important to elucidate the functional aspects of immediate-early (IE) genes at the initial phase of the infection. To study the functional role of the HHV-6B IE gene encoding U95, we generated a U95-Myc fusion protein and screened a pretransformed bone marrow cDNA library for U95-interacting proteins, using yeast-two hybrid analysis. The most frequently appearing U95-interacting protein identified was GRIM-19, which belongs to the family of genes associated with retinoid-interferon mortality and serves as an essential component of the oxidative phosphorylation system. This interaction was verified by both coimmunoprecipitation and confocal microscopic coimmunolocalization. Short-term HHV-6B infection of MT-4 T-lymphocytic cells induced syncytial formation, resulted in decreased mitochondrial membrane potential, and led to progressively pronounced ultrastructural changes, such as mitochondrial swelling, myelin-like figures, and a loss of cristae. Compared to controls, RNA interference against U95 effectively reduced the U95 mRNA copy number and abrogated the loss of mitochondrial membrane potential. Our results indicate that the high affinity between U95 early viral protein and GRIM-19 may be closely linked to the detrimental effect of HHV-6B infection on mitochondria. These findings may explain the alternative cell death mechanism of expiration, as opposed to apoptosis, observed in certain productively HHV-6B-infected cells. The interaction between U95 and GRIM-19 is thus functionally and metabolically significant in HHV-6B-infected cells and may be a means through which HHV-6B modulates cell death signals by interferon and retinoic acid.

scholarly journals Involvement of intracellular Ca2+ and K+ in dissipation of the mitochondrial membrane potential and cell death induced by extracellular ATP in hepatocytes

1992 ◽  
Vol 288 (1) ◽  
pp. 207-213 ◽  
Author(s):  
J P Zoeteweij ◽  
B van de Water ◽  
H J de Bont ◽  
G J Mulder ◽  
J F Nagelkerke
Keyword(s):  
Cell Death ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Rat Hepatocytes ◽  
Extracellular Atp ◽  
Complete Loss ◽  
Isolated Rat Hepatocytes ◽  
Isolated Mitochondria ◽  
Isolated Rat

Isolated rat hepatocytes were incubated with extracellular ATP to induce a prolonged increase in intracellular Ca2+ ([Ca2+]i) and a loss of viability within 2 h. By using video-intensified fluorescence microscopy, the effects of exposure to extracellular ATP on [Ca2+]i, mitochondrial membrane potential (MMP) and cell viability were determined simultaneously in individual living hepatocytes. The increase in [Ca2+]i on exposure to ATP was followed by a decreasing MMP; there were big differences between individual cells. Complete loss of the MMP occurred before cell death was observed. Omission of K+ from the incubation medium decreased the cytotoxicity of ATP; under these conditions, intracellular K+ was decreased by more than 80%. Treatment with nigericin also depleted intracellular K+ and decreased ATP-induced toxicity. Protection against loss of viability by means of a decrease in intracellular [K+] was reflected by maintenance of the MMP. These observations suggest that ATP-induced cell death may be caused by a mechanism that has been described for isolated mitochondria: after an increase in Ca2+ levels, a K+ influx into mitochondria is induced, which finally disrupts the MMP and leads to cell death.

Anti-Glycophorin C Induces a Loss of Mitochondrial Membrane Potential but Fails To Activate Apoptotic Caspases.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4097-4097
Author(s):  
Gregory A. Denomme ◽  
Jonathan Micieli ◽  
Jenny Shu ◽  
Dan Wang ◽  
Bernard J. Fernandes
Keyword(s):  
Cell Death ◽  
Membrane Potential ◽  
Growth Inhibition ◽  
Mitochondrial Membrane Potential ◽  
K562 Cell ◽  
Mitochondrial Membrane ◽  
K562 Cells ◽  
Suppressive Effect ◽  
Glycophorin C

Abstract The human erythrocyte transmembrane sialoglycoprotein, glycophorin C (GYPC), plays a functional role in regulating red cell shape and mechanical stability. Antibodies to GYPC cause hemolytic disease of the fetus and newborn (HDFN) that is associated with classical Fcγ receptor-mediated phagocytosis. However, in vitro clonogenic studies with cord blood progenitor cells suggest that anti-GYPC also suppresses erythropoiesis, which is consistent with the observations of severe and early fetal anemia and late onset neonatal anemia [Transfus Med2005;15:125–32]. The mechanism of the suppressive effect on erythropoiesis is unknown. The K562 erythroleukemic cell line treated with anti-GYPC is a potential model system to study the suppressive effect of anti-GYPC. The present in vitro studies were designed to confirm the effect of anti-GYPC on K562 cell growth and viability, and to evaluate changes in mitochondrial membrane potential, phosphatidylserine (PS) expression, propidium iodide (PI) binding, and caspase activation. K562 cells fail to grow in the presence of anti-GYPC confirming earlier CFU-E/BFU-E studies [Brit J Haematol2006;133:443–4], and increased the exofacial expression of PS/PI over time. This process was caspase-independent as demonstrated by the failure of Z-VAD, a caspase inhibitor, to reverse growth inhibition and PS/PI expression. A loss of mitochondrial membrane potential was demonstrated using JC-1, a cationic dye that is sensitive to potential-dependent accumulation or loss in mitochondria. There was a 50% increase in K562 cell mitochondrial membrane potential disruption after 2 days of culture with anti-GYPC (see figure). Morphological examination of May Grunwalde Giemsa-stained K562 cells treated with anti-GYPC for 2 days showed a decrease in mitotic activity compared to isotype treated cells. By day 4, the anti-GYPC treated cells were showing evidence of plasma membrane damage and cell death resulting from fragmentation and dissolution of the cytoplasm. The addition of hemin, an oxidative form of iron protoporphyrin IX known to induce erythroid differentiation of K562 cells, to anti-GYPC treated cells reversed growth inhibition by 45% but did not prevent the loss of mitochondrial membrane potential. Overall, although caspases appear to be unimportant in anti-GYPC induced cell death, the mitchondria play an important role as the early events leading to antibody-mediated suppression of erythropoiesis. Mitochondrial Membrane Potential Disruption by Anti-GYPC Mitochondrial Membrane Potential Disruption by Anti-GYPC

113. Loss of mitochondrial membrane potential and increased cell death follow the addition of a novel adjunctive cryoablative procedure

Cryobiology ◽  
2007 ◽  
Vol 55 (3) ◽  
pp. 362
Author(s):  
Dominic M. Clarke ◽  
Robert G. Van Buskirk ◽  
John G. Baust ◽  
Andrew A. Gage ◽  
John M. Baust
Keyword(s):  
Cell Death ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane

scholarly journals The Interferon Stimulator Mitochondrial Antiviral Signaling Protein Facilitates Cell Death by Disrupting the Mitochondrial Membrane Potential and by Activating Caspases

2009 ◽  
Vol 84 (5) ◽  
pp. 2421-2431 ◽  
Author(s):  
Chia-Yi Yu ◽  
Ruei-Lin Chiang ◽  
Tsung-Hsien Chang ◽  
Ching-Len Liao ◽  
Yi-Ling Lin
Keyword(s):  
Cell Death ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Caspase Cleavage ◽  
Infected Cells ◽  
Mitochondrial Antiviral Signaling ◽  
Antiviral Innate Immunity ◽  
Viral Components

ABSTRACT Interferon (IFN) signaling is initiated by the recognition of viral components by host pattern recognition receptors. Dengue virus (DEN) triggers IFN-β induction through a molecular mechanism involving the cellular RIG-I/MAVS signaling pathway. Here we report that the MAVS protein level is reduced in DEN-infected cells and that caspase-1 and caspase-3 cleave MAVS at residue D429. In addition to its well-known function in IFN induction, MAVS is also a proapoptotic molecule that triggers disruption of the mitochondrial membrane potential and activation of caspases. Although different domains are required for the induction of cytotoxicity and IFN, caspase cleavage at residue 429 abolished both functions of MAVS. The apoptotic role of MAVS in viral infection and double-stranded RNA (dsRNA) stimulation was demonstrated in cells with reduced endogenous MAVS expression induced by RNA interference. Even though IFN-β promoter activation was largely suppressed, DEN production was not affected greatly in MAVS knockdown cells. Instead, DEN- and dsRNA-induced cell death and caspase activation were delayed and attenuated in the cells with reduced levels of MAVS. These results reveal a new role of MAVS in the regulation of cell death beyond its well-known function of IFN induction in antiviral innate immunity.

scholarly journals EPAC1 Inhibition Protects the Heart from Doxorubicin-Induced Toxicity

2021 ◽  
Author(s):  
Marianne Mazevet ◽  
Maxance Ribeiro ◽  
Anissa Belhadef ◽  
Delphine Dayde ◽  
Anna Llach ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Membrane Potential ◽  
Dilated Cardiomyopathy ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Dna Intercalation ◽  
Antitumoral Activity ◽  
Ros Generation

Rationale: The widely used chemotherapeutic agent Doxorubicin (Dox) induces cardiotoxicity leading to dilated cardiomyopathy and heart failure. This cardiotoxicity has been related to ROS generation, DNA intercalation, bioenergetic distress and cell death. However, alternative mechanisms are emerging, focusing on signaling pathways. Objective: We investigated the role of Exchange Protein directly Activated by cAMP (EPAC), key factor in cAMP signaling, in Dox-induced cardiotoxicity. Methods and Results: Dox was administrated in vivo (10 +/- 2 mg/kg, i.v.; with analysis at 2, 6 and 15 weeks post injection) in WT and EPAC1 KO C57BL6 mice. Cardiac function was analyzed by echocardiography and intracellular Ca2+ homeostasis by confocal microscopy in isolated ventricular cardiomyocytes. 15 weeks post-injections, Dox-treated WT mice, developed a dilated cardiomyopathy with decreased ejection fraction, increased telediastolic volume and impaired Ca2+ homeostasis, which were totally prevented in the EPAC1 KO mice. The underlying mechanisms were investigated in neonatal and adult rat cardiac myocytes under Dox treatment (1-10 uM). Flow cytometry, Western blot, BRET sensor assay, and RT-qPCR analysis showed that Dox induced DNA damage and cardiomyocyte cell death with apoptotic features rather than necrosis, including Ca2+-CaMKKβ-dependent opening of the Mitochondrial Permeability Transition Pore, dissipation of the Mitochondrial membrane potential, caspase activation, cell size reduction, and DNA fragmentation. Dox also led to an increase in both cAMP concentration and EPAC1 protein level and activity. The pharmacological inhibition of EPAC1 (CE3F4) but not EPAC2 alleviated the whole Dox-induced pattern of alterations including DNA damage, Mitochondrial membrane potential, apoptosis, mitochondrial biogenesis, dynamic, and fission/fusion balance, and respiratory chain activity, suggesting a crucial role of EPAC1 in these processes. Importantly, while preserving cardiomyocyte integrity, EPAC1 inhibition potentiated Dox-induced cell death in several human cancer cell lines. Conclusion: Thus, EPAC1 inhibition could be a valuable therapeutic strategy to limit Dox-induced cardiomyopathy without interfering with its antitumoral activity.

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