Abstract

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Title:: Piezo1 ion channel-mediated fluid shear stress inhibits the apoptosis of MLO-Y4 osteocytes

Author(s):: LIU Zhongcheng; HE Liangzhi; YI Qiong; LIU Xuening; ZHANG Kun; WANG Lifu; GENG Bin; XIA Yayi; JIANG Jin; Gansu Provincial Key Laboratory of Orthopaedics/Department of Orthopaedics, Lanzhou University Second Hospital, Lanzhou 730000, China

Abstract:: Abstract: Objective To investigate the regulation of mechanosensitive ion channel Piezo1 on osteocytes. Methods Immunofluorescence staining was used to investigate the best condition for Piezo1 channel-mediated FSS loaded by the self-developed fluid shear stress (FSS) loading device on MLO-Y4 osteocytes. Piezo1 was intervened with FSS, Piezo1 activator Yoda1, or Piezo1 blocker GsMTx4. The expression levels of apoptosis-related proteins (Cleaved Caspase-3, Bcl-2, and Bax) were analyzed using Western Blot analysis, and the apoptosis rates of MLO-Y4 osteocytes was detected by Hoechst-33258 and flow cytometry. Results The result of immunofluorescence staining indicated that in MLO-Y4 osteocytes exposed to FSS, the expression of Piezo1 had a unimodal tendency of increasing firstly and then decreasing, and that the optimal stimulation condition was 9 dyne/cm2 loading for 30 minutes. Yoda1 inhibited the apoptosis of MLO-Y4 osteocytes (P<0.05), and GsMTx4 promoted the apoptosis of MLO-Y4 osteocytes (P<0.05). Piezo1-mediated FSS inhibited the apoptosis of MLO-Y4 osteocytes (P<0.05). Conclusion When loading FSS at 9 dyne/cm2, the FSS mediated by mechanosensitive ion channel Piezo1 can inhibit the apoptosis of MLO-Y4 osteocytes, and FSS can effectively reverse the apoptosis of MLO-Y4 osteocytes promoted with Piezo1 blocker GsMTx4 at 4 μmol/L for 0.5 h.