Yueda Jihu,1,2,* Ruobing Leng,1,* Mengchang Liu,1,2 Hongjing Ren,1,2 Defu Xie,1,2 Chong Yao,1,2 Hong Yan1,2 

1Clinical College of Medicine, Southwest Medical University, Lu zhou, People’s Republic of China; 2Department of Plastic and Burn Surgery, the Affiliated Hospital of Southwest Medical University, Lu zhou, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Hong Yan, Email zxsswk@163.com

Introduction: Angiotensin (1– 7) (Ang-(1-7)) is an emerging component of the renin-angiotensin system (RAS) with effective anti-fibrosis properties and has been shown to interfere with epithelial-mesenchymal transition (EMT) by numerous studies. In recent years, EMT has been proposed as a new therapeutic target for skin fibrotic diseases such as keloids. However, the effect of Ang-(1-7) on EMT in skin is still unclear. Hence, the purpose of this study was to explore the effect of Ang-(1-7) on Transforming growth factor-β 1(TGF-β 1)–induced EMT of human immortalized keratinocytes HaCaT in vitro.
Methods: The study involved the use of the human immortalized keratinocyte cell line (HaCaT). The cells were cultured in high-glucose DMEM medium with 10% fetal bovine serum and 1% penicillin-streptomycin. Four groups were created for experimentation: control group (Group C), TGF-β 1-treated group (Group T), Ang-(1-7)-treated group (Group A), and a group treated with both TGF-β 1 and Ang-(1-7) (Group A + T). Various assays were conducted, including a cell proliferation assay using CCK-8 solution, a scratch wound healing assay to evaluate cell migration, and Western blotting to detect protein expressions related to cell characteristics. Additionally, quantitative real-time polymerase chain reaction (PCR) was performed to analyze epithelial-mesenchymal transition (EMT) related gene expression levels. The study aimed to investigate the effects of TGF-β 1 and Ang-(1-7) on HaCaT cells.
Results: We found that Ang-(1-7) not only reduced the migration of HaCaT cells induced by TGF-β 1 in vitro but also reduced the expression of α-SMA and vimentin, and restored the protein expression of E-cadherin and claudin-1. Mechanistically, Ang-(1-7) inhibits the phosphorylation levels of Smad2 and Smad3 in the TGF-β 1 canonical pathway, and suppresses the expression of EMT-related transcription factors (EMT-TFs) such as SNAI2, TWIST1, and ZEB1.
Discussion: Taken together, our findings suggest that Ang-(1-7) inhibits TGF-β 1–induced EMT in HaCaT cells in vitro by disrupting the TGF-β 1-Smad canonical signaling pathway. These results may be helpful in the treatment of EMT in skin fibrotic diseases such as keloids.

Keywords: angiotensin (1-7), epithelial-mesenchymal transition, transforming growth factor-β, keratinocytes