title: Reactive nitrogen species is required for the activation of the AMP-activated protein kinase by statin in vivo.
abstract: The AMP-activated protein kinase (AMPK) is reported to mediate the beneficial effects of statin on the vascular functions, but the biochemical mechanisms are incompletely understood. The aim of the study was to determine how statin activates AMPK. Exposure of confluent bovine aortic endothelial cells to simvastatin (statin) dose-dependently increased phosphorylation of AMPK at Thr(172) and activities of AMPK, which was in parallel with increased detection of both LKB1 phosphorylation at Ser(428) and LKB1 nuclear export. Furthermore, statin treatment was shown to increase protein kinase C (PKC)-zeta activity and PKC-zeta phosphorylation at Thr(410)/Thr(403). Consistently, inhibition of PKC-zeta either by pharmacological or genetic manipulations abolished statin-enhanced LKB1 phosphorylation at Ser(428), blocked LKB1 nucleus export, and prevented the subsequent activation of AMPK. Similarly, in vivo transfection of PKC-zeta-specific small interfering RNA in C57BL/6J mice significantly attenuated statin-enhanced phosphorylation of AMPK-Thr(172), acetyl-CoA carboxylase (ACC)-Ser(79), and LKB1-Ser(428). In addition, statin significantly increased reactive oxygen species, whereas preincubation of mito-TEMPOL, a superoxide dismutase mimetic, abolished statin-enhanced phosphorylation of both AMPK-Thr(172) and ACC-Ser(79). Finally, in vivo administration of statin increased 3-nitrotyrosine and the phosphorylation of AMPK and ACC in C57BL/6J mice but not in mice deficient in endothelial nitric-oxide synthase. Taken together, our data suggest that AMPK activation by statin is peroxynitrite-mediated but PKC-zeta-dependent.
authors.affiliation: Sections of Endocrinology and Nephrology, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
authors.forename: Hyoung Chul
authors.initials: HC
authors.lastname: Choi
authors.forename: Ping
authors.initials: P
authors.lastname: Song
authors.forename: Zhonglin
authors.initials: Z
authors.lastname: Xie
authors.forename: Yong
authors.initials: Y
authors.lastname: Wu
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
authors.forename: Miao
authors.initials: M
authors.lastname: Zhang
authors.forename: Yunzhou
authors.initials: Y
authors.lastname: Dong
authors.forename: Shuangxi
authors.initials: S
authors.lastname: Wang
authors.forename: Kai
authors.initials: K
authors.lastname: Lau
authors.forename: Ming-Hui
authors.initials: MH
authors.lastname: Zou
mesh_terms: D055372:AMP-Activated Protein Kinases; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D004789:Enzyme Activation; D005947:Glucose / Q000494:pharmacology; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009097:Multienzyme Complexes / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D010768:Phosphoserine / Q000378:metabolism; D010769:Phosphothreonine / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D021381:Protein Transport; D034741:RNA, Small Interfering / Q000235:genetics; D026361:Reactive Nitrogen Species / Q000378:metabolism*; D000099221:Protein Kinase C zeta
chemical_list: D055372:AMP-Activated Protein Kinases; D000804:Angiotensin II; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase; D005947:Glucose; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D009097:Multienzyme Complexes; D052250:Nitric Oxide Synthase Type III; D010768:Phosphoserine; D010769:Phosphothreonine; D011493:Protein Kinase C; D017346:Protein Serine-Threonine Kinases; D034741:RNA, Small Interfering; D026361:Reactive Nitrogen Species; D000099221:Protein Kinase C zeta