cytochrome-c-t and Atherosclerosis

Epidemiological evidence showed that the particulate matter exposure is associated with atherosclerotic plaque progression, which may be related to foam cell formation, but the mechanism is still unknown. The study was aimed to investigate the toxic effects and possible mechanism of PM

Topics: Animals; Apoptosis; Atherosclerosis; bcl-2-Associated X Protein; Caspase 3; Caspase 9; Cell Line; Cytochromes c; Foam Cells; Lipid Metabolism; Lipoproteins, LDL; Membrane Potential, Mitochondrial; Mice; Particulate Matter; Plaque, Atherosclerotic; RAW 264.7 Cells; Reactive Oxygen Species; Signal Transduction; Up-Regulation

Methylmercury (MeHg) is a bioaccumulative global environmental contaminant present in fishes and seafood. MeHg is the methylated form of mercury emitted from diverse anthropogenic and natural sources. MeHg is accumulated in the aquatic environment and eventually reaches human system via food chain by biomagnification. We have reported previously that the neurotoxic effect of MeHg in rat cerebellum is mitigated by the administration of an ayurvedic medicinal plant, Celastrus paniculatus ethanolic extract. The present study has focussed to further explore the mechanism of action of Celastrus paniculatus against MeHg-induced neurotoxicity in the cerebellum. We have also inspected the effect of Celastrus paniculatus (CP) against MeHg-induced atherosclerotic risk factors like alterations in antioxidant levels, aortic lipid profile, and aortic histology by MeHg in the largest vasculature, aorta, which are the initiating factors of cardiovascular diseases. Male Wistar rats were divided as (i) control, (ii) MeHg (5 mg/kg b.w.), (iii) MeHg + CP (200 mg/kg b.w.), and (iv) CP alone (200 mg/kg b.w.). All were given orally for 21 days. In cerebellum Celastrus paniculatus, there were increased mitochondrial electron transport chain (p < 0.05) activity, reduced cytochrome c release (p < 0.05), and caspase 3 mRNA expression (p < 0.05). In the aorta, MeHg-induced oxidative stress, lipid profile changes, and endothelial denudation were ameliorated by Celastrus paniculatus. Hence, we conclude that Celastrus paniculatus protects against MeHg toxicity by inhibiting mitochondrial cytochrome c/caspase 3 apoptotic pathway in the cerebellum and reducing the development of atherosclerotic risk factors in the aorta.

Topics: Animals; Antioxidants; Aorta; Apoptosis; Atherosclerosis; Caspase 3; Celastrus; Cerebellum; Cytochromes c; Electron Transport; Endothelium, Vascular; Humans; Lipid Metabolism; Male; Methylmercury Compounds; Mitochondria; Oxidative Stress; Phytotherapy; Plant Extracts; Rats; Rats, Wistar; Risk Factors; RNA, Messenger; Water Pollutants, Chemical

Phosphocreatine (PCr) is an exogenous energy substance, which provides phosphate groups for adenosine triphosphate (ATP) cycle and promotes energy metabolism in cells. However, it is still unclear whether PCr has influenced on mitochondrial energy metabolism as well as oxidative phosphorylation (OXPHO) in previous studies. Therefore, the aim of the present study was to investigate the regulation of PCr on lipopolsaccharide (LPS)-induced human umbilical vein endothelial cells (HUVECs) and mitochondrial OXPHO pathway. PCr protected HUVECs against LPS-induced apoptosis by suppressing the mitochondrial permeability transition, cytosolic release of cytochrome c (Cyt C), Ca(2+), reactive oxygen species and subsequent activation of caspases, and increasing Bcl2 expression, while suppressing Bax expression. More importantly, PCr significantly improved mitochondrial swelling and membrane potential, enhanced the activities of ATP synthase and mitochondrial creatine kinase (CKmt) in creatine shuttle, influenced on respiratory chain enzymes, respiratory control ratio, phosphorus/oxygen ratio and ATP production of OXPHO. Above PCr-mediated mitochondrial events were effectively more favorable to reduced form of flavin adenine dinucleotide (FADH2) pathway than reduced form of nicotinamide-adenine dinucleotid pathway in the mitochondrial respiratory chain. Our results revealed that PCr protects against LPS-induced HUVECs apoptosis, which probably related to stabilization of intracellular energy metabolism, especially for FADH2 pathway in mitochondrial respiratory chain, ATP synthase and CKmt. Our findings suggest that PCr may play a certain role in the treatment of atherosclerosis via protecting endothelial cell function.

Topics: Adenosine Triphosphate; Apoptosis; Atherosclerosis; bcl-2-Associated X Protein; Caspases; Creatine Kinase, Mitochondrial Form; Cytochromes c; Cytoprotection; Endothelium, Vascular; Human Umbilical Vein Endothelial Cells; Humans; Lipopolysaccharides; Membrane Potential, Mitochondrial; Mitochondria; Mitochondrial Swelling; Oxidative Phosphorylation; Phosphocreatine; Proto-Oncogene Proteins c-bcl-2; Reactive Oxygen Species

Mitochondrial dysfunction has been implicated in cardiovascular diseases. Elevation of serum retinol binding protein 4 (RBP4) in patients has been linked to cardiovascular disease. However, the role of RBP4 on mitochondrial oxidative stress and vascular oxidative damage is not well demonstrated. Therefore, we evaluated the impact of RBP4 on the mitochondrial reactive oxygen species (ROS) and dynamics in the pathogenesis of cardiovascular diseases.. RBP4 treatment increased mitochondrial superoxide generation in a dose-dependent manner in human aortic endothelial cells (HAECs). Exposure to RBP4 also promoted mitochondrial dysfunction as determined by decreased mitochondrial content and integrity as well as membrane potential in HAECs. Incubation with RBP4 suppressed mitofusin (Mfn)-1 protein expression, but enhanced dynamin-related protein-1 (Drp1) and fission-1 (Fis1) protein expression in HAECs, suggesting an impairment of mitochondrial fusion and fission dynamics. Moreover, RBP4 treatment significantly induced endothelial apoptosis, increased the expression of Cytochrome C and Bax, but decreased the expression of Bcl-2. Furthermore, RBP4 stimulation suppressed phosphatidyl inositol 3-kinase (PI3K)/Akt signaling in HAECs. Finally, RBP4-Tg mice exhibited severe mitochondrial dysfunction and vascular oxidative damage in aorta compared with wide-type C57BL/6J mice.. The present study uncovers a novel mechanism through which RBP4 induces vascular oxidative damage and accelerates the development of atherosclerosis.

Topics: Animals; Apoptosis; Atherosclerosis; bcl-2-Associated X Protein; Cells, Cultured; Cytochromes c; Dose-Response Relationship, Drug; Dynamins; Endothelial Cells; GTP Phosphohydrolases; Humans; Membrane Potential, Mitochondrial; Membrane Proteins; Mice, Inbred C57BL; Mice, Transgenic; Microtubule-Associated Proteins; Mitochondria; Mitochondrial Dynamics; Mitochondrial Membrane Transport Proteins; Mitochondrial Proteins; Oxidative Stress; Phosphatidylinositol 3-Kinase; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; Retinol-Binding Proteins, Plasma; Signal Transduction; Superoxides; Time Factors

Virus infection has been shown to accelerate atherosclerosis. Serological studies indicate a link between the Herpes simplex virus (HSV) infection and atherosclerosis, which is initiated and progression of which is promoted by such factors as oxidized low-density lipoprotein (ox-LDL)-induced endothelial dysfunction. In order to recognize the direct role of HSV-2 in endothelial dysfunction, the present study investigated the infection of HSV-2 in endothelial ECV304 cells and the induction of cell apoptosis in the presence of ox-LDL. We firstly examined the HSV-2 infection by immunohistochemical assay for viral gB protein, quantitative PCR for viral ICP4 mRNA, or via virus growth determination. Then we investigated the regulation of HSV-2 infection on the cell viability and apoptosis, in the absence or presence of ox-LDL. In addition, we analyzed the apoptosis-associated molecules in the HSV-2-infected ECV304 cells. The results demonstrated that HSV-2 infected endothelial ECV304 cells and replicated efficiently, and the virus infection significantly reduced the cell viability and significantly induced cell apoptosis; particularly, cell viability reduction and cell apoptosis induction were aggravated by the ox-LDL presence. Moreover, the western blot assay confirmed the apoptosis induction; there was a significantly high level of released cytochrome c, activated caspase 3 and lyzed Poly (ADP-ribose) polymerase (PARP) by the activated caspase 3 in the HSV-2-infected ECV304 cells, particularly the cells subject to ox-LDL. Thus, we confirmed that HSV-2 infected endothelial ECV304 cells, induced cell apoptosis, which was aggravated by ox-LDL.

Topics: Apoptosis; Atherosclerosis; Caspase 3; Cells, Cultured; Cytochromes c; Endothelial Cells; Herpesvirus 2, Human; Humans; Lipoproteins, LDL; Poly(ADP-ribose) Polymerases

In the immune response, hypohalous acids are generated by activated leukocytes via the release of myeloperoxidase and the formation of H2O2. Although these oxidants have important bactericidal properties, they have also been implicated in causing tissue damage in inflammatory diseases, including atherosclerosis. Hypochlorous acid (HOCl) and hypothiocyanous acid (HOSCN) are the major oxidants formed by myeloperoxidase under physiological conditions, with the ratio of these oxidants dependent on diet and smoking status. HOCl is highly reactive and causes marked cellular damage, but few data are available on the effects of HOSCN on mammalian cells. In this study, we have compared the actions of HOCl and HOSCN on human coronary artery endothelial cells (HCAEC). HOCl reacts rapidly with the cells, resulting in extensive cell death by both apoptosis and necrosis, with necrosis dominating at higher oxidant doses. In contrast, HOSCN is consumed more slowly, with cell death occurring only by apoptosis. Exposure of HCAEC to HOCl and HOSCN induces changes in mitochondrial membrane permeability, which, in the case of HOSCN, is associated with mitochondrial release of proapoptotic factors, including cytochrome c, apoptosis-inducing factor, and endonuclease G. With each oxidant, apoptosis appears to be caspase-independent, with the inactivation of caspases 3/7 observed, and pretreatment of the cells with the caspase inhibitor Z-VAD-fmk having no effect on the extent of cell death. Loss of cellular thiols, depletion of glutathione, and the inactivation of thiol-dependent enzymes, including glyceraldehyde-3-phosphate dehydrogenase, were seen with both oxidants, though to a much greater extent with HOCl. The ability of myeloperoxidase-derived oxidants to induce endothelial cell apoptosis may contribute to the formation of unstable lesions in atherosclerosis. The results with HOSCN may be particularly significant for smokers, who have elevated plasma levels of SCN(-), the precursor of this oxidant.

Topics: Amino Acid Chloromethyl Ketones; Apoptosis; Apoptosis Inducing Factor; Atherosclerosis; Caspase 3; Caspase 7; Caspase Inhibitors; Cell Line; Cell Survival; Coronary Vessels; Cytochromes c; Endodeoxyribonucleases; Endothelial Cells; Glutathione; Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating); Humans; Hydrogen Peroxide; Hypochlorous Acid; Mitochondrial Membranes; Necrosis; Oxidation-Reduction; Permeability; Peroxidase; Sulfhydryl Compounds; Thiocyanates

Chymase released from activated mast cells induces apoptosis of vascular smooth muscle cells (SMCs) in vitro by degrading the pericellular matrix component fibronectin, so causing disruption of focal adhesion complexes and Akt dephosphorylation, which are necessary for cell adhesion and survival. However, the molecular mechanisms of chymase-mediated apoptosis downstream of Akt have remained elusive. Here, we show by means of RT-PCR, Western blotting, EMSA, immunocytochemistry and confocal microscopy, that chymase induces SMC apoptosis by disrupting NF-kappaB-mediated survival signaling. Following chymase treatment, the translocation of active NF-kappaB/p65 to the nucleus was partly abolished and the amount of nuclear p65 was reduced. Pretreatment of SMCs with chymase also inhibited LPS- and IL-1beta-induced nuclear translocation of p65. The chymase-induced degradation of p65 was mediated by active caspases. Loss of NF-kappaB-mediated transactivation resulted in downregulation of bcl-2 mRNA and protein expression, leading to mitochondrial swelling and release of cytochrome c. The apoptotic process involved activation of both caspase 9 and caspase 8. The results reveal that, by disrupting the NF-kappaB-mediated survival-signaling pathway, activated chymase-secreting mast cells can mediate apoptosis of cultured arterial SMCs. Since activated mast cells colocalize with apoptotic SMCs in vulnerable areas of human atherosclerotic plaques, they may participate in the weakening and rupture of atherosclerotic plaques.

Topics: Active Transport, Cell Nucleus; Animals; Apoptosis; Atherosclerosis; Caspases; Cell Survival; Cells, Cultured; Chymases; Cytochromes c; Down-Regulation; Inflammation Mediators; Male; Mast Cells; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; NF-kappa B; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Wistar; RNA, Messenger; Serine Endopeptidases; Signal Transduction; Transcription Factor RelA; Transcriptional Activation

A family of constitutive cell surface ECTO-NOX proteins capable of oxidizing reduced quinones, initially described as NADH oxidases, has offered an opportunity to formulate, for the first time, a complete electron transport chain from the cytosol to oxygen at the cell surface with the ECTO-NOX proteins acting as the terminal oxidases. The ECTO-NOX proteins of the cell surface have been postulated as well to link the accumulation of lesions in mitochondrial DNA to cell surface accumulations of reactive oxygen species as one consequence of their role as a terminal oxidase in a plasma membrane electron transport chain. Of the several ECTO-NOX proteins now known, one is a novel cell surface form (arNOX) associated with lymphocytes, sera, saliva and perspiration of patients of age 50 or older and is capable of directly reducing ferric cytochrome c through the generation of superoxide. Because of their cell surface location, ECTO-NOX proteins capable of superoxide generation in response to aging would serve to propagate the aging cascade both to adjacent cells and to oxidize circulating lipoproteins. The generation of superoxide associated with aging is inhibited by coenzyme Q10. As such, the findings provide a rational basis for the antiaging activity of circulating coenzyme Q10 in the prevention of atherosclerosis and other aging-related oxidative changes in cell membranes and circulating lipoproteins.

Topics: Adult; Aged; Aged, 80 and over; Aging; Atherosclerosis; Cytochromes c; DNA, Mitochondrial; Humans; Middle Aged; NADH, NADPH Oxidoreductases; Neoplasm Proteins; Spectrophotometry

Topics: Arteriosclerosis; Atherosclerosis; Cytochromes; Cytochromes c; Humans