title: Nε-carboxymethyllysine-mediated endoplasmic reticulum stress promotes endothelial cell injury through Nox4/MKP-3 interaction.
abstract: N(ε)-carboxymethyllysine (CML) is an important driver of diabetic vascular complications and endothelial cell dysfunction. However, how CML dictates specific cellular responses and the roles of protein tyrosine phosphatases and ERK phosphorylation remain unclear. We examined whether endoplasmic reticulum (ER) localization of MAPK phosphatase-3 (MKP-3) is critical in regulating ERK inactivation and promoting NADPH oxidase-4 (Nox4) activation in CML-induced endothelial cell injury. We demonstrated that serum CML levels were significantly increased in type 2 diabetes patients and diabetic animals. CML induced ER stress and apoptosis, reduced ERK activation, and increased MKP-3 protein activity in HUVECs and SVECs. MKP-3 siRNA transfection, but not that of MKP-1 or MKP-2, abolished the effects of CML on HUVECs. Nox4-mediated activation of MKP-3 regulated the switch to ERK dephosphorylation. CML also increased the integration of MKP-3 with ERK, which was blocked by silencing MKP-3. Exposure of antioxidants abolished CML-increased MKP-3 activity and protein expression. Furthermore, immunohistochemical staining of both MKP-3 and CML was increased, but phospho-ERK staining was decreased in the aortic endothelium of streptozotocin-induced and high-fat diet-induced diabetic mice. Our results indicate that an MKP-3 pathway might regulate ERK dephosphorylation through Nox4 during CML-triggered endothelial cell dysfunction/injury, suggesting that therapeutic strategies targeting the Nox4/MKP-3 interaction or MKP-3 activation may have clinical implications for diabetic vascular complications.
authors.affiliation: Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan; Department of Social Work, Tunghai University, Taichung, Taiwan.
authors.forename: Wen-Jane
authors.initials: WJ
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan; Institute of Biomedical Sciences, National Chung Hsing University, Taichung 402, Taiwan; Rong Hsing Research Center for Translational Medicine, and National Chung Hsing University, Taichung 402, Taiwan.
authors.forename: Wayne Huey-Herng
authors.initials: WH
authors.lastname: Sheu
authors.affiliation: Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Shing-Hwa
authors.initials: SH
authors.lastname: Liu
authors.affiliation: Department of Obstetrics and Gynecology, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Yu-Chiao
authors.initials: YC
authors.lastname: Yi
authors.affiliation: Department of Obstetrics and Gynecology, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Wei-Chih
authors.initials: WC
authors.lastname: Chen
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Shih-Yi
authors.initials: SY
authors.lastname: Lin
authors.affiliation: Cardiovascular Center, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Kae-Woei
authors.initials: KW
authors.lastname: Liang
authors.affiliation: Institute of Nuclear Energy Research, Atomic Energy Council, Longtan, Taoyuan, Taiwan.
authors.forename: Chin-Chang
authors.initials: CC
authors.lastname: Shen
authors.affiliation: Department of Nutrition and Institute of Biomedical Nutrition and Hung-Kuang University, Taichung, Taiwan.
authors.forename: Hsiang-Yu
authors.initials: HY
authors.lastname: Yeh
authors.affiliation: Department of Food and Nutrition, Hung-Kuang University, Taichung, Taiwan.
authors.forename: Li-Yun
authors.initials: LY
authors.lastname: Lin
authors.affiliation: Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan; Institute of Biomedical Sciences, National Chung Hsing University, Taichung 402, Taiwan.
authors.forename: Yi-Ching
authors.initials: YC
authors.lastname: Tsai
authors.affiliation: Institute of Biomedical Sciences, National Chung Hsing University, Taichung 402, Taiwan.
authors.forename: Hsing-Ru
authors.initials: HR
authors.lastname: Tien
authors.affiliation: Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan.
authors.forename: Maw-Rong
authors.initials: MR
authors.lastname: Lee
authors.affiliation: Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan.
authors.forename: Tzung-Jie
authors.initials: TJ
authors.lastname: Yang
authors.affiliation: Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan; Institute of Biomedical Sciences, National Chung Hsing University, Taichung 402, Taiwan; Rong Hsing Research Center for Translational Medicine, and National Chung Hsing University, Taichung 402, Taiwan. Electronic address: mlsheu@nchu.edu.tw.
authors.forename: Meei-Ling
authors.initials: ML
authors.lastname: Sheu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D002461:Cell Line, Transformed; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000139:chemically induced / Q000378:metabolism*; D059305:Diet, High-Fat; D054642:Dual Specificity Phosphatase 6 / Q000235:genetics / Q000378:metabolism*; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects / Q000235:genetics; D042783:Endothelial Cells / Q000187:drug effects* / Q000502:physiology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D006801:Humans; D008239:Lysine / Q000031:analogs & derivatives* / Q000097:blood / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D058990:Molecular Targeted Therapy; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics
chemical_list: D034741:RNA, Small Interfering; C048496:N(6)-carboxymethyllysine; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C498910:NOX4 protein, human; D054642:Dual Specificity Phosphatase 6; D008239:Lysine
keywords: AGEs; CML; ERK; Free radicals; Human endothelial cells; MKP-3; Nox4