Function of Transient Receptor Potential Cation Channel Subfamily V Member 4 (TRPV4) as a Mechanical Transducer in Flow-sensitive Segments of Renal Collecting Duct System
Function of Transient Receptor Potential Cation Channel Subfamily V Member 4 (TRPV4) as a Mechanical Transducer in Flow-sensitive Segments of Renal Collecting Duct System
复制标题
DOI：
10.1074/jbc.m111.308411
复制
发表时间：
2012-03-16
影响因子：
4.8
通讯作者：
O'Neil, Roger G.
中科院分区：
文献类型：
--
作者：
Berrout, Jonathan;Jin, Min;O'Neil, Roger G.
TRPV4钙离子通透通道对机械刺激敏感。在目前的研究中，我们在肾脏切片上进行免疫细胞化学染色，并在分离的、裂开的小管段进行功能评估(钙成像)，以确定TRPV4在集合管系统中的表达部位和血流依赖的功能。染色结果显示，TRPV4在整个集合管系统中呈强阳性表达，主要细胞类型--主细胞(PC)的顶端(腔)/尖下区域表达最强，间质细胞(IC)的弥漫染色较多。利用钙离子荧光成像和选择性TRPV4激动剂GSK1016790A，我们展示了分裂开放的皮质集合管和连接小管的PC和ICs中具有功能的TRPV4通道。该激动剂在无细胞外钙离子或TRPV4缺陷性动物肾小管内钙离子升高的情况下，不能有效地诱导[钙](I)升高。最重要的是，管腔(心尖)液体流量增加10倍，导致钙离子快速持续内流，这种内流可被TRPV通道阻滞剂Ru红或TRPV4缺乏动物分离的小管中的钙离子所消除。我们得出结论，TRPV4在整个集合管系统中高度表达，在那里它似乎起到了流诱导机械应力的传感器/换能器的作用。
The TRPV4 Ca2+-permeable channel is sensitive to mechanical stimuli. In the current study we have employed immunocytochemical staining in kidney slices and functional assessments (Ca2+ imaging) in isolated, split-opened, tubule segments to define TRPV4 sites of expression and flow-dependent function in the collecting duct system. Staining patterns revealed strong expression of TRPV4 along the entire collecting duct system with highest levels at the apical (luminal)/subapical region of the principal cells (PCs), the dominant cell type, with more diffuse staining in intercalated cells (ICs). Using fluorescence Ca2+ imaging and the selective TRPV4 agonist, GSK1016790A, we demonstrated functional TRPV4 channels in PCs and ICs of split-opened cortical collecting ducts and connecting tubules. The agonist was ineffective in inducing a rise in [Ca2+](i) in the absence of extracellular Ca2+ or in tubules from TRPV4-deficient animals. Most importantly, a 10-fold elevation in luminal (apical) fluid flow induced a rapid and sustained influx of Ca2+ that was abolished by the TRPV channel inhibitor, ruthenium red, or in tubules isolated from TRPV4 deficient animals. We concluded that TRPV4 is highly expressed along the entire collecting duct system where it appears to function as a sensor/transducer of flow-induce mechanical stresses.