Piezo1-ERK1/2-YAP Signaling Cascade Regulates the Proliferation of Urine-derived Stem Cells on Collagen Gels

Background Urine-derived stem cells (USCs) were considered to be an ideal source of stem cells for repairing urological diseases. However, the proliferative ability of USCs significantly decreased when cultured on plastic dishes, which limited their clinical application. It was found that collagen gels could promote the proliferation of USCs, but the underlying molecular mechanisms were unclear.Objective The study aims to investigate the role of the mechanically activated cation channel Piezo1 and the transcriptional coactivator YAP in the regulation of proliferation of USCs on collagen gels.Methods USCs were cultured on collagen gels (group COL), or plastic dishes (group NON). MTT assay, Scratch assay, EDU staining, and immunofluorescence (IF) of Ki67 were performed to evaluate the proliferation of USCs; IF of YAP was conducted to observe its nuclear localization; calcium imaging experiment was executed to evaluate the function of Piezo1; western blot was used to compare changes in protein expression of YAP, LATS1, ERK1/2, and p-ERK1/2. In addition, the regulatory effect of YAP on the proliferative capacity of USCs was confirmed by intervening YAP with its inhibitor verteporfin (VP); and the inhibitor or activator of Piezo1, GsMTx4 or Yoda1 was used to explore the effect of Piezo1 on the nuclear localization of YAP, the proliferation of USCs and the regeneration of injured bladder.Results The results showed that cell proliferation was significantly enhanced in USCs in the COL group with the nuclear accumulation of YAP compared with the NON group and VP attenuated these effects. The expression and function of Piezo1 were higher in the COL group compared with the NON group. Blockage of Piezo1 by GsMTx4 decreased nuclear localization of YAP, the proliferation of USCs, and caused the failure of bladder reconstruction. Activation of Piezo1 by Yoda1 increased the nuclear expression of YAP, and the proliferation of USCs, which further improved the regeneration of the injured bladder. Finally, the ERK1/2 rather than LATS1 was revealed to participate in the Piezo1/YAP signal cascades of USCs proliferation.Conclusion Taken together, Piezo1-ERK1/2-YAP signal cascades were involved in regulating the proliferation ability of USCs in collagen gels which would be beneficial for the regeneration of the bladder.