2. Title: The TRPC3 channel regulates expression of fibronectin via NFκB signaling in response to mechanical strain
Authors: Hisako Ishise, Kenichiro Kawai, Kazutoshi Fujita, Yohei Sotsuka, Toshihiro Fujiwara, Soh Nishimoto, and Masao Kakibuchi
Affiliation: Department of Plastic Surgery, Hyogo College of Medicine
Purpose: It is well known that mechanical force influences the wound healing process. In cutaneous wound healing, fibronectin is robustly secreted from fibroblasts and promotes wound healing, especially wound contraction. In this study, we investigated the link between TRPC3 activation and the expression of fibronectin.
Materials and methods: TRPC3-overexpressing NIH3T3 mouse fibroblasts were created using a PMXS-IRES-GFP system. TRPC3-overexpressing or control vector-transfected fibroblasts were seeded onto silicon chambers and mechanically stretched for 24 hours at a frequency of 10 cycles/min with/without Pyr3 (TRPC3 inhibitor) or Wedelolactone (NFκB inhibitor). Then, the expression level of fibronectin was examined by real-time PCR and Western blotting. The activity of NFκB was also investigated by Western blot analysis using an anti-phospho-NFκB antibody. The translocation of NFκB into nuclei in response to mechanical stretching was assessed by immunocytochemistry.
Results: TRPC3-overexpressing fibroblasts that were subjected to cyclic stretching showed robust expression of fibronectin and activation of NFκB. The activation of NFκB that occurred upon stretching was attenuated by pharmacological blockade of TRPC3 or NFκB.
Conclusions: The TRPC3 channel activates NFκB signaling pathways in response to mechanical stimuli, leading to the enhanced production of fibronectin, which may account for hypertrophic scarring of the skin.