Aims: Phenotypic change of vascular smooth muscle cells (VSMCs) contributes a lot in obesity induced vascular pathological remodeling. The endoplasmic reticulum (ER) is critical for maintaining VSMC function, but the accumulation of misfolded proteins in the ER impairs cell function. As the major ER protein quality control responsible for clearing misfolded proteins, ER-associated degradation (ERAD) whose key member is HRD1 plays vital role in lipid metabolism, but its function in VSMC phenotypic change remains poorly understood.Main methods: The level of HRD1 expression was analyzed in aortic tissues of mice fed with a high-fat diet (HFD). The HE and EVG (VERHOEFF'S VAN GIESON) staining were used to demonstrate vascular pathological changes. Cripr and transcriptomic analysis were applied in in vitro studies to explore the cellular mechanism. Key ndings: Data showed a signi cant reduction of HRD1 in aortic tissues of mice under HFD feeding. VSMC phenotypic change and HRD1 downregulation were detected by cholesterol treatment.Transcriptomic and further analysis of HRD1-KO VSMCs showed that HRD1 de ciency increased the expression of genes related with ER stress, proliferation, and migration, but decreased the VSMC contractile-related genes. HRD1 de ciency in VSMCs also exacerbated the proliferation, migration, and ROS production induced by cholesterol, which promoted the VSMC phenotypic change process.Signi cance: Our results proved that HRD1 plays an essential role in the contractile homeostasis of VSMCs by negatively regulating ER stress. Thus, HRD1 may have the potential to be a therapeutic target in lipid metabolic disorders induced vascular remodeling caused by VSMC phenotypic change.
HighlightsWe proved HRD1 KO exacerbated the proliferation, migration, and ROS production induced by cholesterol, promoted the VSMCs transfer from a contractile phenotype to a synthetic phenotype, our study provided a new target in treating the vascular pathological remodeling caused by VSMC phenotypic change.University, as well as the Animal Laboratory Administration Center and Ethics Committee of the Sun Yat-Sen University, the third a liated hospital. Male C57Bl6/J mice were purchased from the Guangdong Medical Laboratory Animal center. The persistent ID is SYSU-IACUC-2022-001869. All mice were maintained in a SPF environment with controlled humidity and temperature (22 ± 2°C) under a 12 h:12 h light/dark cycle and received water and a chow diet (CD) ad libitum. At 2 months of age, the mice were divided to receive CD (3.86 kcal/g), or HFD (a very high fat, 60% calories from fat; 5.55 kcal/g diet) for 4 months.
Manipulations of Cultured VSMCsHuman primary VSMCs were purchased from Guangzhou BIOSPECIES Company (batch number 20220704), shown in Table SI, cultured in DMEM containing 10% fetal bovine serum and antibiotics (1% ER: endoplasmic reticulum VSMC: vascular smooth muscle cell ERAD: endoplasmic reticulum-associated degradation UPR: unfolded protein response
