PINK1/Parkin‐mediated mitophagy promotes apelin‐13‐induced vascular smooth muscle cell proliferation by AMPKα and exacerbates atherosclerotic lesions

Abstract Aberrant proliferation of vascular smooth muscle cells (VSMC) is a critical contributor to the pathogenesis of atherosclerosis (AS). Our previous studies have demonstrated that apelin‐13/APJ confers a proliferative response in VSMC, however, its underlying mechanism remains elusive. In this study, we aimed to investigate the role of mitophagy in apelin‐13‐induced VSMC proliferation and atherosclerotic lesions in apolipoprotein E knockout (ApoE‐/‐) mice. Apelin‐13 enhances human aortic VSMC proliferation and proliferative regulator proliferating cell nuclear antigen expression in dose and time‐dependent manner, while is abolished by APJ antagonist F13A. We observe the engulfment of damage mitochondria by autophagosomes (mitophagy) of human aortic VSMC in apelin‐13 stimulation. Mechanistically, apelin‐13 increases p‐AMPKα and promotes mitophagic activity such as the LC3I to LC3II ratio, the increase of Beclin‐1 level and the decrease of p62 level. Importantly, the expressions of PINK1, Parkin, VDAC1, and Tom20 are induced by apelin‐13. Conversely, blockade of APJ by F13A abolishes these stimulatory effects. Human aortic VSMC transfected with AMPKα, PINK1, or Parkin and subjected to apelin‐13 impairs mitophagy and prevents proliferation. Additional, apelin‐13 not only increases the expression of Drp1 but also reduces the expressions of Mfn1, Mfn2, and OPA1. Remarkably, the mitochondrial division inhibitor‐1(Mdivi‐1), the pharmacological inhibition of Drp1, attenuates human aortic VSMC proliferation. Treatment of ApoE‐/‐ mice with apelin‐13 accelerates atherosclerotic lesions, increases p‐AMPKα and mitophagy in aortic wall in vivo. Finally, PINK1‐/‐ mutant mice with apelin‐13 attenuates atherosclerotic lesions along with defective in mitophagy. PINK1/Parkin‐mediated mitophagy promotes apelin‐13‐evoked human aortic VSMC proliferation by activating p‐AMPKα and exacerbates the progression of atherosclerotic lesions.