Department of Pharmacology, Anhui Medical University, Hefei, Anhui, 230032, P. R. China.
Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort Worth, Texas, 76107, USA.
Sci Rep. 2017 Jun 23;7(1):4145. doi: 10.1038/s41598-017-04067-z.
The present study was conducted to determine if TRPC6 regulates glomerular filtration rate (GFR) and the contractile function of glomerular mesangial cells (MCs). GFR was assessed in conscious TRPC6 wild type and knockout mice, and in anesthetized rats with and without in vivo knockdown of TRPC6 in kidneys. We found that GFR was significantly greater, and serum creatinine level was significantly lower in TRPC6 deficient mice. Consistently, local knockdown of TRPC6 in kidney using TRPC6 specific shRNA construct significantly attenuated Ang II-induced GFR decline in rats. Furthermore, Ang II-stimulated contraction and Ca entry were significantly suppressed in primary MCs isolated from TRPC6 deficient mice, and the Ca response could be rescued by re-introducing TRPC6. Moreover, inhibition of reverse mode of Na-Ca exchange by KB-R7943 significantly reduced Ca entry response in TRPC6-expressing, but not in TRPC6-knocked down MCs. Ca entry response was also significantly attenuated in Na free solution. Single knockdown of TRPC6 and TRPC1 resulted in a comparable suppression on Ca entry with double knockdown of both. These results suggest that TRPC6 may regulate GFR by modulating MC contractile function through multiple Ca signaling pathways.
本研究旨在确定 TRPC6 是否调节肾小球滤过率（GFR）和肾小球系膜细胞（MC）的收缩功能。在清醒的 TRPC6 野生型和敲除小鼠以及麻醉的大鼠中评估了 GFR，其中在肾脏中体内敲低 TRPC6 的大鼠存在和不存在。我们发现，TRPC6 缺陷型小鼠的 GFR 显著增加，血清肌酐水平显著降低。一致地，使用 TRPC6 特异性 shRNA 构建体在肾脏中局部敲低 TRPC6 可显著减弱 Ang II 诱导的大鼠 GFR 下降。此外，从 TRPC6 缺陷型小鼠分离的原代 MC 中，Ang II 刺激的收缩和 Ca 内流明显受到抑制，并且可以通过重新引入 TRPC6 来挽救 Ca 反应。此外，通过 KB-R7943 抑制反向 Na-Ca 交换显著降低了在表达 TRPC6 但未敲低 TRPC6 的 MC 中的 Ca 内流反应。在无 Na 溶液中，Ca 内流反应也明显减弱。单独敲低 TRPC6 和 TRPC1 可导致 Ca 内流反应与双敲低时相当的抑制。这些结果表明，TRPC6 可能通过多种 Ca 信号通路调节 MC 收缩功能来调节 GFR。
