论文部分内容阅读
AIM: Atherosclerotic calcification is highly linked with plaque instability and cardiovascular events. Adenosine monophosphateactivated protein kinase( AMPK) has been involved in the pathogenesis of various cardiovascular disease. The contributions of AMPKαsubunits to the development of atherosclerotic calcification in vivo remained unknown. We hypothesized that AMPKα subunits may play a role in the development of atherosclerotic calcification. METHODS: Atherosclerotic calcification was generated by 24-week fed of western diet in Apo E~(-/-)background mice. Calcification was evaluated in aortic roots and innominate arteries of Apo E~(-/-)mice or in mice with dual deficiencies of Apo E and AMPKα subunits globally( AMPKα1 and AMPKα2),or vascular smooth muscle cell(VSMC)-specific or macrophage-specific knockout of AMPKα1 with atherosclerotic calcification pone diet. The mechanism of AMPKα1 in regulating Runx2 was further explored in human aortic VSMC. RESULTS: Ablation of AMPKα1 but not AMPKα2 in Apo E~(-/-)background promoted atherosclerotic calcification with increased Runt-related transcription factor( Runx2) expression in VSMC compared with Apo E~(-/-)mice. Conversely,chronic administration of metformin,which activated AMPK,markedly reduced atherosclerotic calcification and Runx2 expression in Apo E~(-/-)mice but had less effects in Apo E~(-/-)/ AMPKα1- /-mice. Furthermore,VSMC- but not macrophage-specific deficiency of AMPKα1 in Apo E~(-/-)background promoted atherosclerotic calcification in vivo compared with the controls. AMPKα1 silencing in human aortic VSMC prevented Runx2 from proteasome degradation to trigger osteoblastic differentiation of VSMC. Conversely,activation of AMPK led to Runx2 instability by inducing its small ubiquitin-like modifier modification( SUMOylation). Protein inhibitor of activated STAT-1( PIAS1),the SUMO E3-ligase of Runx2,was directly phosphorylated by AMPKα1 at serine 510,to enhance its SUMO E3-ligase activity. Ablation of PIAS1 serine 510 phosphorylation inhibited metformin-induced Runx2 SUMOylation,and subsequently prevented the effect of metformin on reducing ox LDL-triggered Runx2 expression in human aortic VSMC. CONCLUSION: Deficiency of AMPKα1 in VSMC increases Runx2 expression and promotes atherosclerotic calcification in vivo. AMPKα1 phosphorylates PIAS1 to enhance Runx2 SUMOyalation and subsequent degradation.
AIM: Atheroslerotic calcification is highly linked with plaque instability and cardiovascular events. Adenosine monophosphate activated protein kinase (AMPK) has been involved in the pathogenesis of various cardiovascular disease. The contributions of AMPKαsubunits to the development of atherosclerotic calcification in vivo rendered unknown. We hypothesized that METHODS: Atherosclerotic calcification was generated by 24-week fed of western diet in Apo E ~ (- / -) background mice. Calcification was evaluated in aortic roots and innominate arteries of Apo E ~ (- / -) mice or in mice with dual deficiencies of Apo E and AMPKα subunits globally (AMPKα1 and AMPKα2), or vascular smooth muscle cell (VSMC) -specific or macrophage-specific knockout of AMPKα1 with atherosclerotic calcification pone diet. The mechanism of AMPKα1 in regulating Runx2 was further explored in human aortic VSMC. RESULTS: Ablation of AMPKα1 b ut not AMPKα2 in Apo E ~ (- / -) background promoted atherosclerotic calcification with increased Runt-related transcription factor (Runx2) expression in VSMC compared with Apo E ~ (- / -) mice. Conversely, chronic administration of metformin, which activated AMPK, markedly reduced atherosclerotic calcification and Runx2 expression in Apo E ~ (- / -) mice but with less effects in Apo E ~ (- / -) / AMPKα1- / -mice. AMPKα1 in Apo E ~ (- / -) background promoted atherosclerotic calcification in vivo compared with the controls. AMPKα1 silencing in human aortic VSMC prevented Runx2 from proteasome degradation to trigger osteoblastic differentiation of VSMC. Conversely, activation of AMPK led to Runx2 instability by inducing Its small ubiquitin-like modifier modification (SUMOylation). Protein inhibitor of activated STAT-1 (PIAS1), the SUMO E3-ligase of Runx2, was directly phosphorylated by AMPKα1 at serine 510, to enhance its SUMO E3-ligase activity. of PIAS1 serine 510 phosphorylation inhibited metformin-induced Runx2 SUMOylation, and subsequently prevented the effect of metformin on reducing ox LDL-triggered Runx2 expression in human aortic VSMC. CONCLUSION: Deficiency of AMPK alpha 1 in VSMC increases Runx2 expression and promotes atherosclerotic calcification in vivo. AMPK alpha 1 phosphorylates PIAS1 to enhance Runx2 SUMOyalation and subsequent degradation.