Polycystin-1 Downregulation Induced Vascular Smooth Muscle Cells Phenotypic Alteration and Extracellular Matrix Remodeling in Thoracic Aortic Dissection

Jing Zhang,Li-Xin Wang,Fei Liu,Wen-Rui Ma,Yu-Bin He,Wei Zhang,Jie Xing

doi:10.3389/fphys.2020.548055

Abstract

ObjectivePolycystin-1 (PC-1) is a protein encoded by the gene of polycystic kidney disease-1 (PKD-1). This study was designed to investigate the regulatory mechanisms of PC-1 on phenotypes of aortic vascular smooth muscle cells (VSMCs) and functions of extracellular matrix (ECM) in thoracic aortic dissection (TAD).MethodsAortic tissues from patients with TAD and healthy controls were collected, primary aortic VSMCs were also isolated. Immunohistochemistry, immunofluorescence, and immunocytochemistry was used to visualize the target proteins. Western blot and RT-qPCR were used to examine the expression of mRNA and proteins. Lentivirus infection was used to downregulate or overexpress PC-1.ResultsCompared with the control group, expression of PC-1 and the contractile phenotypic markers of VSMCs were decreased in TAD group, whereas expression of the synthetic markers of VSMCs, matrix metalloproteinase (MMP)-2, collagen I and collagen III were increased. The phosphorylation of mTOR, S6K and S6 were also elevated in TAD group. PC-1 downregulation of aortic VSMCs inhibited the expression of the contractile markers, but elevated the expression of the synthetic markers, MMP-2, collagen I and collagen III compared with the control group. The phosphorylation of mTOR, S6K and S6 were also increased in PKD-1-knockdown VSMCs. PC-1 upregulation reversed all these expression characteristics in aortic VSMCs. Furthermore, rapamycin treatment to PKD-1-knockdown VSMCs inhibited the effects caused by PC-1 downregulation.ConclusionOur study revealed PC-1 downregulation induces aortic VSMCs phenotypic alteration and ECM remodeling via activation of mTOR/S6K/S6 signaling pathway. Downregulation of PC-1 might be a potential mechanism for the development and progression of TAD. Rapamycin might be a potential inhibitor to attenuate the development and progression of TAD.

Highlights

MATERIALS AND METHODSThoracic aortic dissection (TAD) is characterized by the tear of aortic intima and the false lumen in aortic media (Wang et al, 2006; Nienaber et al, 2016), which is a fatal condition with the risks of aortic rupture and malperfusion of branches
In order to investigate the expression of PC-1 and the relationship between the level of PC-1 and the phenotype of vascular smooth muscle cells (VSMCs) in control group and TAD group, IHC, Reverse Transcription Quantitative Polymerase Chain Reaction (RT-qPCR) and western blot were performed
The expression of matrix metalloproteinase (MMP)-1 showed no significant differences between control and TAD groups (Figures 1A6,B,D7,E6; p > 0.05 for both)

Summary

Introduction

MATERIALS AND METHODSThoracic aortic dissection (TAD) is characterized by the tear of aortic intima and the false lumen in aortic media (Wang et al, 2006; Nienaber et al, 2016), which is a fatal condition with the risks of aortic rupture and malperfusion of branches. TAD can be clinically classified into Stanford type A (ascending aorta) and Stanford type B (descending aorta). Extracellular matrix (ECM) dysfunction in aortic media is the common histological feature of TAD (Wang et al, 2006). The aortic media is comprised of vascular smooth muscle cells (VSMCs) and ECM (Amabili et al, 2019). VSMCs are the main source of ECM in the aortic media, including two different functional conditions, namely, the contractile and the synthetic phenotype. The synthetic VSMCs exhibit the enhanced proliferation, migration and ECM synthesis (Wang Y. et al, 2019). The phenotypic alteration between contractile and synthetic VSMCs is indispensable for the maintenance of aortic homeostasis. The pathological phenotypic alteration may play a pivotal role in the pathogenesis of TAD

Results

Discussion

Conclusion