Angiotensin II Activates Yes-Associated Protein (YAP) in Fibroblast Promoting Deep Fascia Remodeling

The deep fascia, traditionally regarded as a passive structural tissue, is now recognized as a metabolically and biologically active structure where biochemical signals and biomechanical forces interact to influence proprioception, pain, force transmission, and adaptation to mechanical load. In this study, the convergence point between Angiotensin II (Ang II) signaling via its receptor, Angiotensin type 1 receptor (AT1R), and the mechanosensor Yes-associated protein (YAP) was investigated in human fascial fibroblasts. The presence of angiotensin II (Ang II) receptors was confirmed in fibroblasts from the deep fascia, with the AT1 receptor being the most prevalent subtype. Short-term exposure to Ang II (15-30 min) caused YAP dephosphorylation and its translocation to the nucleus, indicating YAP activation. Notably, prolonged Ang II treatment (7 days) significantly increased the expression of fibrosis-related genes, including collagen types I and III (COL1A1, COL3A1), and hyaluronan binding protein 2 (HABP2). This gene expression was decreased by pretreatment with the AT1R antagonist irbesartan or the YAP inhibitor verteporfin. Additionally, Ang II promoted fibroblast proliferation/migration, key features of fibrotic progression, through AT1R-dependent pathways. These findings show that Ang II acts as both a biochemical and biomechanical signal in the deep fascia, activating YAP signaling and promoting fibrotic remodeling. Our results uncover a new Ang II-YAP pathway in fascial fibroblasts, offering potential targets for therapy in fibrosis and related conditions involving the deep fascia.