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

• Main Authors: Maki Yoneda, Hiroka Suzuki, Noriyuki Hatano, Sayumi Nakano, Yukiko Muraki, Ken Miyazawa, Shigemi Goto, Katsuhiko Muraki
• Format: Article
• Language: English
• Published: MDPI AG 2019-10-01
• Series: International Journal of Molecular Sciences
• Subjects: trpv4; piezo1; yoda1; mc3t3-e1 cells; mechanical stimulation; cell proliferation
• Online Access: https://www.mdpi.com/1422-0067/20/19/4960

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 <i>Piezo1</i> and <i>Trpv4</i> 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 <i>Piezo1</i> 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.