Ebihara Lisa, Acharya Pooja, Tong Jun-Jie
Center of Proteomics and Molecular Therapeutics, Rosalind Franklin University of Medicine and Science, North Chicago, IL, United States.
Discipline of Physiology and Biophysics, Rosalind Franklin University of Medicine and Science, North Chicago, IL, United States.
Front Physiol. 2022 Jan 31;13:814651. doi: 10.3389/fphys.2022.814651. eCollection 2022.
During accommodation, the lens changes focus by altering its shape following contraction and relaxation of the ciliary muscle. At the cellular level, these changes in shape may be accompanied by fluid flow in and out of individual lens cells. We tested the hypothesis that some of this flow might be directly modulated by pressure-activated channels. In particular, we used the whole cell patch clamp technique to test whether calcium-activated-chloride channels (CaCCs) expressed in differentiating lens cells are activated by mechanical stimulation. Our results show that mechanical stress, produced by focally perfusing the lens cell at a constant rate, caused a significant increase in a chloride current that could be fully reversed by stopping perfusion. The time course of activation and recovery from activation of the flow-induced current occurred rapidly over a time frame similar to that of accommodation. The flow-induced current could be inhibited by the TMEM16A specific CaCC blocker, Ani9, suggesting that the affected current was predominantly due to TMEM16A chloride channels. The mechanism of action of mechanical stress did not appear to involve calcium influx through other mechanosensitive ion channels since removal of calcium from the bath solution failed to block the flow-induced chloride current. In conclusion, our results suggest that CaCCs in the lens can be rapidly and reversibly modulated by mechanical stress, consistent with their participation in regulation of volume in this organ.
在调节过程中,晶状体通过睫状肌的收缩和松弛改变其形状来改变焦点。在细胞水平上,这些形状变化可能伴随着液体进出单个晶状体细胞。我们检验了这样一种假设,即这种液体流动中的一些可能直接由压力激活通道调节。特别是,我们使用全细胞膜片钳技术来测试分化中的晶状体细胞中表达的钙激活氯通道(CaCCs)是否被机械刺激激活。我们的结果表明,以恒定速率局部灌注晶状体细胞所产生的机械应力导致氯电流显著增加,停止灌注后该电流可完全逆转。流动诱导电流的激活和激活恢复的时间进程在与调节相似的时间范围内迅速发生。流动诱导电流可被TMEM16A特异性CaCC阻滞剂Ani9抑制,这表明受影响的电流主要归因于TMEM16A氯通道。机械应力的作用机制似乎不涉及通过其他机械敏感离子通道的钙内流,因为从浴液中去除钙未能阻断流动诱导的氯电流。总之,我们的结果表明,晶状体中的CaCCs可被机械应力快速且可逆地调节,这与其参与该器官的体积调节一致。