Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany.
Department of Nephrology and Hypertension, University of Erlangen-Nuremberg, Erlangen, Germany.
J Mol Med (Berl). 2020 May;98(5):659-671. doi: 10.1007/s00109-020-01894-y. Epub 2020 Mar 18.
Polycystic kidney disease (PKD) leads to continuous decline of renal function by growth of renal cysts. Enhanced proliferation and transepithelial chloride secretion through cystic fibrosis transmembrane conductance regulator (CFTR) and Ca-activated TMEM16A Cl channels is thought to cause an increase in cyst volume. Recent work shows the pro-proliferative role of the Ca activated Cl channel TMEM16A (anoctamin 1), and demonstrates the essential contribution of TMEM16A to CFTR-dependent Cl secretion. The present data demonstrate an increase in intracellular Ca ([Ca]i) signals and Cl secretion by TMEM16A, in renal collecting duct principle cells from dog (MDCK) and mouse (M1) as well as primary tubular epithelial cells from PKD1-/- knockout mice. M1 organoids proliferated, increased expression of TMEM16A, and secreted Cl upon knockdown of endogenous polycystin 1 or 2 (PKD1,2), by retroviral transfection with shPKD1 and shPKD2, respectively. Knockdown of PKD1 or PKD2 increased basal intracellular Ca levels and enhanced purinergic Ca release from endoplasmic reticulum. In contrast, ryanodine receptors were found not to be expressed in mouse renal epithelial cells and caffeine had no effects on [Ca]i. Ca signals, proliferation, and Cl secretion were largely reduced by knockdown or blockade of TMEM16A. TMEM16A may be therefore important for enhanced Ca release from IP-sensitive Ca stores in polycystic kidney disease. KEY MESSAGES: • ADPKD leads to continuous decline of renal function by growth of renal cysts. • Knockdown of PKD1 or PKD2 increases TMEM16A expression. • TMEM16A enhanced intracellular Ca signals, Cl secretion, and proliferation. • TMEM16A contributes to cyst growth in ADPKD.
多囊肾病 (PKD) 导致肾脏囊肿的生长导致肾功能持续下降。囊性纤维化跨膜电导调节因子 (CFTR) 和 Ca 激活的 TMEM16A Cl 通道的增强增殖和跨上皮氯离子分泌被认为会导致囊肿体积增加。最近的工作表明 Ca 激活的氯离子通道 TMEM16A（anoctamin 1）具有促增殖作用，并证明 TMEM16A 对 CFTR 依赖性 Cl 分泌有重要贡献。本研究数据表明，在犬 (MDCK) 和小鼠 (M1) 的肾集合管主细胞以及 PKD1-/- 敲除小鼠的原代肾小管上皮细胞中，TMEM16A 可增加细胞内 Ca([Ca]i) 信号和 Cl 分泌。在 M1 类器官中，通过逆转录病毒转染 shPKD1 和 shPKD2 分别敲低内源性多囊蛋白 1 或 2 (PKD1,2) 后，细胞增殖、TMEM16A 表达增加，并分泌 Cl。PKD1 或 PKD2 的敲低增加了基础细胞内 Ca 水平，并增强了内质网中嘌呤能 Ca 释放。相比之下，在小鼠肾上皮细胞中未发现肌醇 1,4,5-三磷酸受体表达，咖啡因对 [Ca]i 无影响。Ca 信号、增殖和 Cl 分泌主要通过 TMEM16A 的敲低或阻断而减少。因此，TMEM16A 可能在多囊肾病中从 IP 敏感的 Ca 库中增强 Ca 释放中起重要作用。关键信息：• ADPKD 导致肾脏囊肿的生长导致肾功能持续下降。• PKD1 或 PKD2 的敲低增加 TMEM16A 的表达。• TMEM16A 增强细胞内 Ca 信号、Cl 分泌和增殖。• TMEM16A 有助于 ADPKD 中的囊肿生长。
