Department of Physiology, KU Open Innovation Center, Research Institute of Medical Science, Konkuk University School of Medicine, Chungju, Chungbuk, 380-701, South Korea.
Sensory Research Center, Creative Research initiatives, College of Pharmacy, Seoul National University, Seoul, 151-742, South Korea.
Sci Rep. 2019 Apr 23;9(1):6446. doi: 10.1038/s41598-019-42492-4.
Recent parallel studies clearly indicated that Merkel cells and the mechanosensitive piezo2 ion channel play critical roles in the light-touch somatosensation. Moreover, piezo2 was suggested to be a light-touch sensing ion channel without a role in pain sensing in mammals. However, biophysical characteristics of piezo2, such as single channel conductance and sensitivities to various mechanical stimuli, are unclear, hampering a precise understanding of its role in touch sensation. Here, we describe the biophysical properties of piezo2 in human Merkel cell carcinoma (MCC)-13 cells; piezo2 is a low-threshold, positive pressure-specific, curvature-sensitive, mechanically activated cation channel with a single channel conductance of ~28.6 pS. Application of step indentations under the whole-cell mode of the patch-clamp technique, and positive pressures ≥5 mmHg under the cell-attached mode, activated piezo2 currents in MCC-13 and human embryonic kidney 293 T cells where piezo2 was overexpressed. By contrast, application of a negative pressure failed to activate piezo2 in these cells, whereas both positive and negative pressure activated piezo1 in a similar manner. Our results are the first to demonstrate single channel recordings of piezo2. We anticipate that our findings will be a starting point for a more sophisticated understanding of piezo2 roles in light-touch sensation.
最近的平行研究清楚地表明，默克尔细胞和机械敏感的 Piezo2 离子通道在轻触觉感觉中起着关键作用。此外，Piezo2 被认为是一种轻触感觉感应离子通道，而在哺乳动物中没有在疼痛感觉中发挥作用。然而，Piezo2 的生物物理特性，如单通道电导和对各种机械刺激的敏感性，尚不清楚，这阻碍了对其在触觉感知中的作用的精确理解。在这里，我们描述了 Piezo2 在人 Merkel 细胞癌 (MCC)-13 细胞中的生物物理特性；Piezo2 是一种低阈值、正压特异性、曲率敏感、机械激活的阳离子通道，单通道电导约为 28.6 pS。在全细胞膜片钳技术的细胞贴附模式下，应用阶跃凹陷，以及在细胞贴附模式下，正压≥5mmHg，可激活 MCC-13 和 Piezo2 过表达的人胚肾 293T 细胞中的 Piezo2 电流。相比之下，在这些细胞中应用负压不能激活 Piezo2，而 Piezo1 以类似的方式被正压和负压激活。我们的研究结果首次证明了 Piezo2 的单通道记录。我们预计，我们的发现将为更深入地了解 Piezo2 在轻触感觉中的作用提供一个起点。
