cytochrome-c-t and Diabetic-Angiopathies

Mellithemia are diabetic patients' emblematic syndrome, which would induce vasculopathy resulting from apoptosis of vascular endothelial cells. The pathological mechanism of high glucose-induced apoptosis of vascular endothelial cells is investigated in the present study utilizing HUVEC cells. As high glucose-induced apoptosis is caused by elevated mitochondrial permeability-mediated release of mitochondrial cytochrome c, voltage-dependent anion channel (VDAC1), the controller of mitochondrial permeability, and its regulator Bax were investigated. Our results suggest that upregulation of VDAC1 is the central event in high glucose-induced cell apoptosis, since silencing VDAC1 reduced high glucose-induced upregulation of mitochondrial/cellular Bax; thus silencing VDAC1 recovered the high glucose-reduced binding of Bax to VDAC1, which finally reduced the high mitochondrial permeability. Besides, high glucose increased VDAC1 expression by elevating the expression of SREBP1 and SREBP2, the tanscriptional factor of VDAC1. Those findings indicate that SREBP1 or SREBP2/VDAC1 could be novel targets for the prevention of diabetic vasculopathy.

Topics: Apoptosis; Cytochromes c; Diabetic Angiopathies; Gene Expression Regulation; Glucose; Human Umbilical Vein Endothelial Cells; Humans; Mitochondria; Sterol Regulatory Element Binding Protein 1; Sterol Regulatory Element Binding Protein 2; Voltage-Dependent Anion Channel 1

Diabetes is a major driver of cardiovascular disease, but the underlying mechanisms remain elusive. Prolyl-isomerase Pin1 recognizes specific peptide bonds and modulates function of proteins altering cellular homoeostasis. The present study investigates Pin1 role in diabetes-induced vascular disease.. In human aortic endothelial cells (HAECs) exposed to high glucose, up-regulation of Pin1-induced mitochondrial translocation of pro-oxidant adaptor p66(Shc) and subsequent organelle disruption. In this setting, Pin1 recognizes Ser-116 inhibitory phosphorylation of endothelial nitric oxide synthase (eNOS) leading to eNOS-caveolin-1 interaction and reduced NO availability. Pin1 also mediates hyperglycaemia-induced nuclear translocation of NF-κB p65, triggering VCAM-1, ICAM-1, and MCP-1 expression. Indeed, gene silencing of Pin1 in HAECs suppressed p66(Shc)-dependent ROS production, restored NO release and blunted NF-kB p65 nuclear translocation. Consistently, diabetic Pin1(-/-) mice were protected against mitochondrial oxidative stress, endothelial dysfunction, and vascular inflammation. Increased expression and activity of Pin1 were also found in peripheral blood monocytes isolated from diabetic patients when compared with age-matched healthy controls. Interestingly, enough, Pin1 up-regulation was associated with impaired flow-mediated dilation, increased urinary 8-iso-prostaglandin F2α and plasma levels of adhesion molecules.. Pin1 drives diabetic vascular disease by causing mitochondrial oxidative stress, eNOS dysregulation as well as NF-kB-induced inflammation. These findings provide molecular insights for novel mechanism-based therapeutic strategies in patients with diabetes.

Topics: Analysis of Variance; Animals; Aorta; Case-Control Studies; Cells, Cultured; Chemokine CCL2; Cytochromes c; Diabetic Angiopathies; Endothelial Cells; Endothelium, Vascular; Gene Knockdown Techniques; Glucose; Humans; Hyperglycemia; Intercellular Adhesion Molecule-1; Male; Mice, Inbred C57BL; Mitochondrial Diseases; NF-kappa B; NIMA-Interacting Peptidylprolyl Isomerase; Nitric Oxide Synthase; Nitric Oxide Synthase Type III; Oxidative Stress; Peptidylprolyl Isomerase; Reactive Oxygen Species; Shc Signaling Adaptor Proteins; Src Homology 2 Domain-Containing, Transforming Protein 1; Up-Regulation; Vascular Cell Adhesion Molecule-1; Vasculitis

Patients with diabetes mellitus, particularly those with cardiovascular complications, have increased risk of mortality when subject to anesthetics and surgery, compared with non-diabetic patients. Anesthetics may exert pressure on the cardiovascular system of diabetic patients, directly or by aggravating pre-existing cardiovascular complications. Advanced glycation end products (AGEs) are extremely accumulated in diabetes mellitus, and are confirmed to play an important role in the pathogenesis of diabetic microvascular and macrovascular complications. The purpose of the present study was to investigate the regulatory role of etomidate, which is widely used as intravenous general anesthetics, on the viability and apoptosis of human endothelial Eahy926 cells, in the presence of AGEs. The results demonstrated that etomidate and Glu-BSA (one type of AGE) synergistically reduced the human endothelial Eahy926 cell viability and induced cell apoptosis. In addition, western blot assay of apoptosis-associated molecules indicated that both agents synergistically upregulated the cytochrome c release, activated the apoptosis executor, caspase 3, and promoted the poly-ADP-ribose polymerase (PARP) lysis. Further results confirmed that the two agents synergistically promoted oxidative stress by decreasing mitochondrial respiratory chain complex IV and mitochondrial membrane potential (MMP), while upregulating reactive oxygen species (ROS) and mitochondrial superoxide. In conclusion, the results presented in this study offer a novel insight into the mechanisms of endothelial cell apoptosis in response to etomidate in the presence of AGEs. These results suggest that oxidative stress has important role in the synergistic promotion of apoptosis by etomidate and AGEs in endothelial Eahy926 cells.

Topics: Anesthetics, Intravenous; Apoptosis; Caspase 3; Cell Survival; Cells, Cultured; Cytochromes c; Diabetes Mellitus; Diabetic Angiopathies; Drug Synergism; Endothelial Cells; Etomidate; Glycation End Products, Advanced; Humans; Mitochondrial Diseases; Oxidative Stress; Poly(ADP-ribose) Polymerases