Role of Nuclear receptor subfamily 1 group D member 1 in the proliferation, migration of VSMC and vascular intimal hyperplasia.

Abstract

Excessive proliferation and migration of vascular smooth muscle cells (VSMCs) causes neointimal hyperplasia after percutaneous vascular interventions. Nuclear receptor subfamily 1 group D member 1 (NR1D1), a crucial member of circadian clock, is involved in regulation on atherosclerosis and cellular proliferation. However, whether NR1D1 affects vascular neointimal hyperplasia remains unclear. In the current study, we found that activating NR1D1 reduced injury-induced vascular neointimal hyperplasia. Overexpression of NR1D1 reduced the number of Ki-67-positive VSMCs and migrated VSMCs after platelet-derived growth factor (PDGF)-BB treatment. Mechanistically, NR1D1 suppressed the phosphorylation of AKT and two main effectors of mammalian target of rapamycin complex 1 (mTORC1), S6 and 4EBP1 in PDGF-BB-challenged VSMCs. Both re-activation of mTORC1 by Tuberous sclerosis 1 siRNA (siTsc1) and re-activation of AKT by SC-79 abolished NR1D1-mediated inhibitory effects on proliferation and migration of VSMCs. Moreover, decreased mTORC1 activity induced by NR1D1 was also reversed by SC-79. Simultaneously, Tsc1 knockdown abolished the vascular protective effects of NR1D1 in vivo. In conclusion, NR1D1 reduces vascular neointimal hyperplasia by suppressing proliferation and migration of VSMCs in an AKT/mTORC1-dependent manner.