Low shear stress-induced blockage of autophagic flux impairs endothelial barrier and facilitates atherosclerosis in mice

Ruhao Cao; Ruxian Sun; Yuanzhi Ye; Pingge Tian; Bin Huang; Haowen Ye; Libing Dai; Zirong Lan; Jia Liu; Li Li

doi:10.1016/j.yexcr.2024.114071

Low shear stress-induced blockage of autophagic flux impairs endothelial barrier and facilitates atherosclerosis in mice

Exp Cell Res. 2024 May 8;439(1):114071. doi: 10.1016/j.yexcr.2024.114071. Online ahead of print.

Authors

Ruhao Cao¹, Ruxian Sun¹, Yuanzhi Ye², Pingge Tian¹, Bin Huang¹, Haowen Ye¹, Libing Dai³, Zirong Lan², Jia Liu⁴, Li Li⁵

Affiliations

¹ Department of Cardiology, Guangzhou Red Cross Hospital, Jinan University, Guangzhou, 510220, China.
² Department of Cardiology, Laboratory of Heart Center, Zhujiang Hospital, Southern Medical University, Guangdong Provincial Key Laboratory of Cardiac Function and Microcirculation, Guangdong Provincial Biomedical Engineering Technology Research Center for Cardiovascular Disease, Guangzhou, 510280, China.
³ Guangzhou Institute of Traumatic Surgery, Guangzhou Red Cross Hospital, Jinan University, Guangzhou, 510220, China.
⁴ VIP Medical Service Center, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510630, China. Electronic address: liuj683@mail.sysu.edu.cn.
⁵ Department of Cardiology, Guangzhou Red Cross Hospital, Jinan University, Guangzhou, 510220, China. Electronic address: lilygs@ext.jnu.edu.cn.

PMID: 38729336
DOI: 10.1016/j.yexcr.2024.114071

Abstract

Atherosclerosis preferentially occurs in areas with low shear stress (LSS) and oscillatory flow. LSS has been demonstrated to correlate with the development of atherosclerosis. The sphingosine 1-phosphate receptor 1 (S1PR1), involving intravascular blood flow sensing, regulates vascular development and vascular barrier function. However, whether LSS affects atherosclerosis via regulating S1PR1 remains incompletely clear. In this study, immunostaining results of F-actin, β-catenin, and VE-cadherin indicated that LSS impaired endothelial barrier function in human umbilical vein endothelial cells (HUVECs). Western blot analysis showed that LSS resulted in blockage of autophagic flux in HUVECs. In addition, autophagy agonist Rapamycin (Rapa) antagonized LSS-induced endothelial barrier dysfunction, whereas autophagic flux inhibitor Bafilomycin A1 (BafA1) exacerbated it, indicating that LSS promoted endothelial barrier dysfunction by triggering autophagic flux blockage. Notably, gene expression analysis revealed that LSS downregulated S1PR1 expression, which was antagonized by Rapa. Selective S1PR1 antagonist W146 impaired endothelial barrier function of HUVECs under high shear stress (HSS) conditions. Moreover, our data showed that expression of GAPARAPL2, a member of autophagy-related gene 8 (Atg8) proteins, was decreased in HUVECs under LSS conditions. Autophagic flux blockage induced by GAPARAPL2 knockdown inhibited S1PR1, aggravated endothelial barrier dysfunction of HUVECs in vitro, and promoted aortic atherosclerosis in ApoE^-/- mice in vivo. Our study demonstrates that autophagic flux blockage induced by LSS downregulates S1PR1 expression and impairs endothelial barrier function. GABARAPL2 inhibition is involved in LSS-induced autophagic flux blockage, which impairs endothelial barrier function via downregulation of S1PR1.

Keywords: Atherosclerosis; Autophagy; Endothelial barrier function; GAPARAPL2; S1PR1; Shear stress.