The TRPV4 Cation Channel Mediates Stretch-evoked Ca2+ Influx and ATP Release in Primary Urothelial Cell Cultures
The TRPV4 Cation Channel Mediates Stretch-evoked Ca2+ Influx and ATP Release in Primary Urothelial Cell Cultures
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DOI：
10.1074/jbc.m109.020206
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发表时间：
2009-08-07
影响因子：
4.8
通讯作者：
Tominaga, Makoto
中科院分区：
文献类型：
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作者：
Mochizuki, Tsutomu;Sokabe, Takaaki;Tominaga, Makoto
瞬时受体电位通道最近已被牵连在泌尿生殖系统的生理功能。在这项研究中，我们研究了瞬时受体电位香草酸4（TRPV 4）通道在小鼠原代尿路上皮细胞培养的拉伸传感机制中的作用。选择性TRPV 4激动剂4 α-佛波醇12，13-二癸酸酯（4 α-PDD）在野生型（WT）尿路上皮细胞中诱发Ca 2+内流，但在TRPV 4缺陷（TRPV 4KO）细胞中不诱发Ca 2+内流。我们建立了一个细胞牵张系统，以研究牵张引起的细胞内Ca 2+浓度和ATP释放的变化。牵张刺激引起WT和TRPV 4KO细胞内Ca 2+以牵张速度和距离依赖性方式增加。然而，在TRPV 4KO尿路上皮细胞中，与WT细胞相比，细胞内Ca 2+响应于牵张刺激的增加显著减弱。牵拉诱发的Ca 2+增加WT urothrombosis的钌红，一种广泛的TRP通道阻滞剂的存在下，部分减少，而在TRPV 4KO细胞没有显示这样的减少。在WT尿路上皮细胞中，在拉伸刺激或4 α-PDD给药后发生了有效的ATP释放，这在TRPV 4KO细胞中被显著抑制。在钌红存在下或在细胞外Ca 2+不存在下，拉伸依赖性ATP释放几乎完全消除。这些结果表明，TRPV 4感觉膀胱尿道的扩张，这是在尿液储存期间在排尿反射通路中转化为ATP信号。
Transient receptor potential channels have recently been implicated in physiological functions in a urogenital system. In this study, we investigated the role of transient receptor potential vanilloid 4 (TRPV4) channels in a stretch sensing mechanism in mouse primary urothelial cell cultures. The selective TRPV4 agonist, 4 alpha-phorbol 12,13-didecanoate (4 alpha-PDD) evoked Ca2+ influx in wild-type (WT) urothelial cells, but not in TRPV4-deficient (TRPV4KO) cells. We established a cell-stretch system to investigate stretch-evoked changes in intracellular Ca2+ concentration and ATP release. Stretch stimulation evoked intracellular Ca2+ increases in a stretch speed- and distance-dependent manner in WT and TRPV4KO cells. In TRPV4KO urothelial cells, however, the intracellular Ca2+ increase in response to stretch stimulation was significantly attenuated compared with that in WT cells. Stretch-evoked Ca2+ increases in WT urothelium were partially reduced in the presence of ruthenium red, a broad TRP channel blocker, whereas that in TRPV4KO cells did not show such reduction. Potent ATP release occurred following stretch stimulation or 4 alpha-PDD administration in WT urothelial cells, which was dramatically suppressed in TRPV4KO cells. Stretch-dependent ATP release was almost completely eliminated in the presence of ruthenium red or in the absence of extracellular Ca2+. These results suggest that TRPV4 senses distension of the bladder urothelium, which is converted to an ATP signal in the micturition reflex pathway during urine storage.