PCSK9通过诱导血管平滑肌细胞表型转换促进动脉粥样硬化OA

Aim To investigate the role and molecular mechanism of proprotein convertase subtilisin/kexin type 9(PCSK9)in the occurrence and development of atherosclerosis(As).Methods Mouse primary vascular smooth muscle cells(VSMCs)were treated with platelet-derived growth factor-BB(PDGF-BB)for different durations.Cell mi-gration ability was evaluated by scratch assay,and the expression of phenotypic transition markers and PCSK9 was detected by Western blot.Mouse primary VSMCs were infected with Ad-PCSK9 adenovirus to examine the expression of contractile and synthetic marker proteins,as well as cell proliferation and migration capabilities.PCSK9 expression was overex-pressed via adenovirus or inhibited by small interfering RNA(siRNA),and the expression levels of nuclear factor-κB(NF-κB),Krüppel-like factor 4(KLF4),and myocardin(MYOCD)were detected.Immunohistochemistry,immunoflu-orescence,Oil Red O staining,and hematoxylin-eosin(HE)staining were used to analyze the expression of related mole-cules,lipid deposition,and plaque area in aortic plaques of VSMC-specific PCSK9 overexpression(PCSK9sm OE)mice and PCSK9 conditional knockout(PCSK9flox/flox)mice.Results PCSK9 was colocalized with VSMCs in the medial layer and atherosclerotic plaques.Compared with contractile VSMCs in the medial layer,PCSK9 expression was significantly elevated in synthetic VSMCs within the plaques.PDGF-BB upregulated PCSK9 in a time-dependent manner,along with the synthetic phenotypic marker proteins osteopontin(OPN)and epiregulin(EREG),while downregulating the contractile marker proteins smooth muscle myosin heavy chain(SMMHC),α-smooth muscle actin(α-SMA),calponin,and smooth muscle 22α(SM22α),and enhanced cell migration capacity.Ad-PCSK9 promoted the phenotypic transformation of VSMCs from contractile to synthetic phenotype,significantly enhanced DNA replication activity and cell migration ability,downregulated MYOCD expression,and upregulated KLF4 and NF-κB p65 expression.Conversely,siRNA-mediated PC-SK9 inhibition showed opposite effects.Histological analysis revealed that VSMC-specific overexpression of PCSK9 pro-moted aortic plaque formation and increased plaque instability in atherosclerotic mice.Conclusions PCSK9 can in-duce VSMC phenotypic transformation from the contractile to synthetic phenotype,exacerbating the atherosclerotic lesions in mice.This mechanism may involve the signaling crosstalk among NF-κB,KLF4,and MYOCD.