Astragalus Polysaccharide Relieves Systemic Sclerosis Skin Fibrosis by Regulating miR-30b/PTP4A1 Axis

Abstract

Background: Systemic sclerosis (SSc) is an autoimmune disease characterized by vascular disease and tissue fibrosis in the skin and internal organs. Astragalus polysaccharide (APS) is an extract from dried stem of Astragalus membranaceus which can effectively delay SSc progression. The present study aimed to explore the role and mechanism of APS on SSc skin fibrosis. Methods: In vivo, bleomycin (BLM) was used to establish SSc skin fibrosis mice model. After that, the mice were intravenously injected with APS daily for 21 days. Hematoxylin-eosin (HE) staining and Masson staining were applied to detect the pathological changes in skin tissues. The hydroxyproline content of skin tissues was used to assess collagen deposition. In vitro, human foreskin fibroblast-1 (HFF-1) cells were stimulated by transforming growth factor-β1 (TGF-β1) to establish skin fibroblast fibrosis. HFF1 cells were treated with APS and transfected with micro RNA (miRNA)-30b mimic, inhibitor and short hairpin RNA against PTP4A1 (sh-PTP4A1). qRT-PCR (quantitative real-time polymerase chain reaction) and western blot were used to assess fibrosis-related markers expression. Dual luciferase reporter assay was carried out to explore the relationship between miR-30b and PTP4A1. Results: Our study found that in vivo, BLM induction increased skin thickness, inflammatory infiltration, and collagen accumulation, whereas APS intervention reversed BLM-induced SSc skin fibrosis and up-regulated miR-30b expression. In vitro, TGF-β1 intervention up-regulated fibrosis-related markers expression, which was reversed by APS. In addition, miR-30b inhibitor blocked APS effect on alleviating skin fibrosis. Therefore, we speculate that PTP4A1 is a potential target for the mechanism of miR-30b. Knockout of PTP4A1 eliminated the effect of miR-30b inhibitors on TGF-β1 and APS-induced HFF-1 cells. Conclusions: APS relieved SSc skin fibrosis by miR-30b upregulation targeting PTP4A1, which provides a novel insight to treat SSc.