Affiliation:
1. School of Basic Medical Sciences, Guangdong Pharmaceutical University, No. 280 East Outer Ring Road, Panyu District, Guangzhou, China
2. Department of Infectious and Tropical Diseases, The Second Affiliated Hospital of Hainan Medical University, Haikou, China
3. Guangdong Province Key Laboratory of Pharmaceutical Bioactive Substances, Guangdong Pharmaceutical University, Guangzhou, China
4. Guangdong Province Engineering and Technology Center for Molecular Probe and Bio-medicine Imaging, Guangzhou, China
Abstract
Context. Excessive proliferation of vascular smooth muscle cells (VSMCs) plays a critical role in the development of cardiovascular diseases. β-Sitosterol exerts protective effects against the cardiovascular disease. However, whether β-sitosterol protects against the excessive proliferation of VSMCs remain unclear. Objective. To explore the effects of β-sitosterol on VSMC proliferation. Materials and Methods. A7r5 cells were pretreated with 2 µM angiotensin II (Ang II) for 24 hr to establish an excessive VSMC proliferation model, followed by treatment with β-sitosterol for 24 hr. Cells were divided into five groups: control, Ang II, and Ang II + β-sitosterol (2, 4, 8 µM). CCK-8 assay, flow cytometry, and Ad-mCherry-GFP-LC3B assay analyzed cell proliferation, cell cycle, cell apoptosis, and autophagic flux. Additionally, the expression of proteins was detected by the western blotting. Results. β-Sitosterol effectively inhibited Ang II-induced A7r5 cell proliferation (IC50 : 6.841 µM at 24 hr). It achieved this by arresting cell cycle progression, promoting apoptosis, inhibiting autophagy, and suppressing the contractile–synthetic phenotypic switch. Mechanistically, β-sitosterol downregulated PCNA, Cyclin D1, and Bcl-2, while upregulating pro-caspase 3, cleaved-caspase 3, and Bax to induce cell cycle arrest and apoptosis. Additionally, it suppressed the contractile–synthetic phenotypic transformation by downregulating OPN and upregulating α-SMA. The Ad-mCherry-GFP-LC3B Assay and western blotting revealed β-sitosterol’s autophagy inhibitory effects by downregulating LC3, ULK1, and Beclin-1 while upregulating P62 expression. Discussion and Conclusion. This study found for the first time that β-sitosterol could inhibit the proliferation of A7r5 cells induced by Ang II. β-Sitosterol treatment may be recommended as a therapeutic strategy to prevent the cardiovascular diseases.
Funder
National Natural Science Foundation of China
Subject
Cancer Research,Cell Biology,Molecular Medicine,General Medicine,Pathology and Forensic Medicine