Qingda granule ameliorates vascular remodeling and phenotypic transformation of adventitial fibroblasts via suppressing the TGF-β1/Smad2/3 pathway

Abstract

Ethnopharmacological relevance: Qingda granule (QDG) exhibits significant therapeutic effects on high blood pressure, vascular dysfunction, and elevated proliferation of vascular smooth muscle cells by inhibiting multiple pathways. However, the effects and underlying mechanisms of QDG treatment on hypertensive vascular remodeling are unclear.

Aim of the study: The aim of this study was to determine the role of QDG treatment in hypertensive vascular remodeling in vivo and in vitro.

Materials and methods: An ACQUITY UPLC I-Class system coupled with a Xevo XS quadrupole time of flight mass spectrometer was used to characterize the chemical components of QDG. Twenty-five spontaneously hypertensive rats (SHR) were randomly divided into five groups, including SHR (equal volume of double distilled water, ddH₂O), SHR + QDG-L (0.45 g/kg/day), SHR + QDG-M (0.9 g/kg/day), SHR + QDG-H (1.8 g/kg/day), and SHR + Valsartan (7.2 mg/kg/day) groups. QDG, Valsartan, and ddH₂O were administered intragastrically once a day for 10 weeks. For the control group, ddH₂O was intragastrically administered to five Wistar Kyoto rats (WKY group). Vascular function, pathological changes, and collagen deposition in the abdominal aorta were evaluated using animal ultrasound, hematoxylin and eosin and Masson staining, and immunohistochemistry. Isobaric tags for relative and absolute quantification (iTRAQ) was performed to identify differentially expressed proteins (DEPs) in the abdominal aorta, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed. Cell Counting Kit-8 assays, phalloidin staining, transwell assays, and western-blotting were performed to explore the underlying mechanisms in primary isolated adventitial fibroblasts (AFs) stimulated with transforming growth factor-β 1 (TGF-β1) with or without QDG treatment.

Results: Twelve compounds were identified from the total ion chromatogram fingerprint of QDG. In the SHR group, QDG treatment significantly attenuated the increased pulse wave velocity, aortic wall thickening, and abdominal aorta pathological changes and decreased Collagen I, Collagen III, and Fibronectin expression. The iTRAQ analysis identified 306 DEPs between SHR and WKY and 147 DEPs between QDG and SHR. GO and KEGG pathway analyses of the DEPs identified multiple pathways and functional processes involving vascular remodeling, including the TGF-β receptor signaling pathway. QDG treatment significantly attenuated the increased cell migration, actin cytoskeleton remodeling, and Collagen I, Collagen III, and Fibronectin expression in AFs stimulated with TGF-β1. QDG treatment significantly decreased TGF-β1 protein expression in abdominal aortic tissues in the SHR group and p-Smad2 and p-Smad3 protein expression in TGF-β1-stimulated AFs.

Conclusions: QDG treatment attenuated hypertension-induced vascular remodeling of the abdominal aorta and phenotypic transformation of adventitial fibroblasts, at least partly by suppressing TGF-β1/Smad2/3 signaling.

Keywords: Adventitial fibroblasts; Hypertension; Qingda granule; TGF-β1/Smad2/3; Vascular remodeling.