Laboratory of Cellular Pharmacology, School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto, Chikusa, Nagoya 464-8650, Japan.
Department of Orthodontics, School of Dentistry, Aichi Gakuin University, Nagoya 464-8650, Japan.
Int J Mol Sci. 2019 Oct 8;20(19):4960. doi: 10.3390/ijms20194960.
Mechanical-loading and unloading can modify osteoblast functioning. Ca 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 and in these cells. We also found that a PIEZO1 agonist, Yoda1, induced Ca response and activated cationic currents in these cells. Ca response was elicited when mechanical stimulation (MS), with shear stress, was induced by fluid flow in the MC3T3-E1 cells. Gene knockdown of 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 Ca response, when both PIEZO1 and TRPV4 are highly expressed.
机械加载和卸载可以改变成骨细胞的功能。钙信号是成骨细胞对机械刺激产生反应的最早事件之一，从而证明了潜在的机械感受器对于感觉的重要性。在这里，我们研究了机械敏感通道 PIEZO1 和 TRPV4 是否参与了成骨细胞 MC3T3-E1 细胞的机械感觉过程。mRNA 表达分析显示这些细胞中 和 的高表达。我们还发现，PIEZO1 激动剂 Yoda1 诱导这些细胞中的 Ca 反应和激活阳离子电流。当通过流体流动在 MC3T3-E1 细胞中诱导剪切力时，机械刺激 (MS) 会引起 Ca 反应。通过 siPiezo1 转染，在 MC3T3-E1 细胞中敲低 ，抑制了 Yoda1 诱导的反应，但未能抑制 MS 诱导的反应。当 MC3T3-E1 细胞用 siTrpv4 转染时，MS 诱导的反应被阻断，Yoda1 反应被减弱。此外，MS 诱导的反应被 TRPV4 拮抗剂 HC-067047 (HC) 抑制。Yoda1 反应也被 HC 在表达 PIEZO1 和 TRPV4 的 MC3T3-E1 细胞和 HEK 细胞中抑制。同时，PIEZO1 和 TRPV4 的激活降低了 MC3T3-E1 的增殖，这分别被 PIEZO1 和 TRPV4 的敲低逆转。总之，TRPV4 和 PIEZO1 是 MC3T3-E1 细胞中不同的机械感受器。然而，PIEZO1 和 TRPV4 改变了这些细胞的增殖，这表明 PIEZO1 和 TRPV4 可能在成骨细胞的机械转导中发挥功能。值得注意的是，还发现当 PIEZO1 和 TRPV4 高度表达时，Yoda1 可以诱导 TRPV4 依赖性 Ca 反应。
