Increased Cthrc1 Activates Normal Fibroblasts and Suppresses Keloid Fibroblasts by Inhibiting TGF-β/Smad Signal Pathway and Modulating YAP Subcellular Location

Keloid may induce severe impairment of life quality for the patients, although keloid is a cutaneous benign tumor. Collagen triple helix repeat containing protein 1 (Cthrc1) was identified as a novel gene that was originally found in adventitial fibroblasts after arterial injury. To address the role of Cthrc1 in keloid, the expression level of Cthrc1 was assessed in normal skin and keloid tissue, as well as in normal fibroblasts (NFs) and keloid fibroblasts (KFs) by using quantitative PCR, Western blotting and immunohistochemical analysis. The results showed that Cthrc1 was increased in keloid tissue and KFs as compared with normal skin and NFs. Meanwhile, CCK8 and Transwell assays found the cellular proliferation and migration of KFs were increased as compared with NFs. Further, to verify the function of Cthrc1 in NFs and KFs, we increased Cthrc1 expression by transfecting lentivirus (LV) vectors LV-Cthrc1. The cellular proliferation and migration, collagen synthesis and the influence on TGF-β and YAP signaling were tested. The cellular proliferation and migration were increased in NFs-Cthrc1 as compared with NFs-control. Meanwhile, YAP expression and nuclear-location was increased in NFs-Cthrc1. On the contrary, when Cthrc1 was overexpressed in KFs, the cellular migration was suppressed and YAP expression was reduced and transferred to cytoplasm in KFs-Cthrc1 as compared with KFs-control. But the expression level of collagen I was decreased and pSmad2/3 nucleus transfer was suppressed in both NFs-Cthrc1 and KFs-Cthrc1 by using Western blotting and immunofluorescence. Increased Cthrc1 activated NFs by promoting YAP nucleus translocation, whereas suppressed KFs by inhibiting YAP nucleus translocation. Enhanced Cthrc1 decreased collagen I in both NFs and KFs by inhibiting TGF-β/Smad pathway. In conclusion, Cthrc1 may play a role in the pathogenesis of keloid by inhibiting collagen synthesis and fibroblasts migration via suppressing TGF-β/Smad pathway and YAP nucleus translocation.