title: The effects of high glucose levels on reactive oxygen species-induced apoptosis and involved signaling in human vascular endothelial cells.
abstract: This study investigated the effects of high glucose levels on human vascular endothelial cells and the expression of apoptosis-associated signaling molecules. Cell proliferation of human umbilical vein endothelial cells (HUVECs) was analyzed by colorimetric assay and cell number counting. Apoptosis was measured by Annexin V/FITC staining and flow cytometry. Gene knockdown was established by transfection of synthesized small interfering RNA. Caspase-3 activation was inhibited by a caspase-3 inhibitor. Protein expression of signaling molecules was measured by Western blot. Glucose significantly decreased HUVEC viability, induced cell apoptosis, and elevated levels of intracellular reactive oxygen species in a concentration and time-dependent manner. Glucose significantly upregulated the Nox4 isoform of nicotinamide adenine dinucleotide phosphate oxidase and phosphatase and tensin homolog (PTEN) protein expression, increased PTEN phosphorylation, and activated caspase-3 in a concentration-dependent manner. Silencing Nox4 and PTEN gene expression and inhibiting caspase-3 activation significantly protected HUVECs from glucose-induced cell apoptosis. Silencing Nox4 significantly normalized the levels of reactive oxygen species in glucose-treated cells; 20 mM glucose obviously upregulated Nox4, PTEN, phosphor-PTEN, and Bax levels, but significantly reduced integrin-linked kinase (ILK) activity, Bcl-2 (B cell lymphoma 2) expression, and protein kinase B (Akt) phosphorylation at serine 473. High glucose levels can reduce cell viability and induce apoptosis in HUVECs through Nox4-produced reactive oxygen species. Elevated levels of reactive oxygen species decreased Bcl-2 expression and increased PTEN expression and phosphorylation, which lead to the subsequent inhibition of ILK-Akt signaling, elevation of Bax expression, and activation of caspase-3.
authors.affiliation: Department of Nutrition, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, People's Republic of China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Hou
authors.forename: Minxiang
authors.initials: M
authors.lastname: Lei
authors.forename: Ke
authors.initials: K
authors.lastname: Hu
authors.forename: Min
authors.initials: M
authors.lastname: Wang
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D005947:Glucose / Q000008:administration & dosage / Q000633:toxicity*; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*
chemical_list: D017382:Reactive Oxygen Species; D005947:Glucose