Journal Article

PIEZO1 and TRPV4, which Are Distinct Mechano-Sensors in the Osteoblastic MC3T3-E1 Cells, Modify Cell-Proliferation

Suzuki, Hiroka, Muraki, Katsuhiko, Miyazawa, Ken, Goto, Shigemi, Yoneda, Maki, Muraki, Yukiko, Nakano, Sayumi, Hatano, Noriyuki

2019

Overview

Mechanical-loading and unloading can modify osteoblast functioning. Ca2+ signaling is one of the earliest events in osteoblasts to induce a mechanical stimulus, thereby demonstrating the importance of the underlying mechanical sensors for the sensation. Here, we examined the mechano-sensitive channels PIEZO1 and TRPV4 were involved in the process of mechano-sensation in the osteoblastic MC3T3-E1 cells. The analysis of mRNA expression revealed a high expression of Piezo1 and Trpv4 in these cells. We also found that a PIEZO1 agonist, Yoda1, induced Ca2+ response and activated cationic currents in these cells. Ca2+ response was elicited when mechanical stimulation (MS), with shear stress, was induced by fluid flow in the MC3T3-E1 cells. Gene knockdown of Piezo1 in the MC3T3-E1 cells, by transfection with siPiezo1, inhibited the Yoda1-induced response, but failed to inhibit the MS-induced response. When MC3T3-E1 cells were transfected with siTrpv4, the MS-induced response was abolished and Yoda1 response was attenuated. Moreover, the MS-induced response was inhibited by a TRPV4 antagonist HC-067047 (HC). Yoda1 response was also inhibited by HC in MC3T3-E1 cells and HEK cells, expressing both PIEZO1 and TRPV4. Meanwhile, the activation of PIEZO1 and TRPV4 reduced the proliferation of MC3T3-E1, which was reversed by knockdown of PIEZO1, and TRPV4, respectively. In conclusion, TRPV4 and PIEZO1 are distinct mechano-sensors in the MC3T3-E1 cells. However, PIEZO1 and TRPV4 modify the proliferation of these cells, implying that PIEZO1 and TRPV4 may be functional in the osteoblastic mechano-transduction. Notably, it is also found that Yoda1 can induce TRPV4-dependent Ca2+ response, when both PIEZO1 and TRPV4 are highly expressed.

• Publisher: MDPI AG,MDPI
• Subject: Animals / Cell Line / Cell Proliferation / Gene expression / Gene Expression Regulation / Gene Knockdown Techniques / Humans / Ion Channels - genetics / Ion Channels - metabolism / Mechanotransduction, Cellular / Membrane Potentials / Mice / Osteoblasts - metabolism / Sensors / Shear stress / Stress, Mechanical / TRPV Cation Channels - genetics / TRPV Cation Channels - metabolism