Department of Systems Biology, Physiology Unit, Faculty of Medicine, University of Alcalá, 28805 Alcalá de Henares, Madrid, Spain; Instituto Reina Sofia de Investigación Renal and REDinREN from Instituto de Salud Carlos III, Madrid, Spain.
Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.
Biochim Biophys Acta Gene Regul Mech. 2017 Sep;1860(9):922-935. doi: 10.1016/j.bbagrm.2017.07.006. Epub 2017 Jul 20.
Two processes are associated with progressive loss of renal function: 1) decreased aquaporin-2 (AQP2) expression and urinary concentrating capacity (Nephrogenic Diabetes Insipidus, NDI); and 2) changes in extracellular matrix (ECM) composition, e.g. increased collagen I (Col I) deposition, characteristic of tubule-interstitial fibrosis. AQP2 expression is regulated by both the ECM-to-intracellular scaffold protein integrin-linked kinase (ILK) by NFATc/AP1 and other transcription factors. In the present work, we used in vivo and in vitro approaches to examine ILK participation in NFATc3/AP-1-mediated increases in AQP2 gene expression. Both NFATc3 knock-out mice and ILK conditional-knockdown mice (cKD-ILK) display symptoms of NDI (polyuria and reduced AQP2 expression). NFATc3 is upregulated in the renal medulla tubular cells of cKD-ILK mice but with reduced nuclear localization. Inner medullary collecting duct mIMCD3 cells were subjected to ILK depletion and transfected with reporter plasmids. Pharmacological activators or inhibitors determined the effect of ILK activity on NFATc/AP-1-dependent increases in transcription of AQP2. Finally, mIMCD3 cultured on Col I showed reduced activity of the ILK/GSK3β/NFATc/AQP2 axis, suggesting this pathway is a potential target for therapeutic treatment of NDI.
1）水通道蛋白-2（AQP2）表达和尿浓缩能力降低（肾性尿崩症，NDI）；2）细胞外基质（ECM）组成的变化，例如胶原 I（Col I）沉积增加，是小管间质纤维化的特征。AQP2 的表达受 ECM-细胞内支架蛋白整合素连接激酶（ILK）的调节，NFATc/AP1 和其他转录因子。在本工作中，我们使用体内和体外方法研究了 ILK 在 NFATc3/AP-1 介导的 AQP2 基因表达增加中的参与。NFATc3 敲除小鼠和 ILK 条件敲除小鼠（cKD-ILK）均表现出 NDI 的症状（多尿和 AQP2 表达减少）。cKD-ILK 小鼠的肾脏髓质管状细胞中 NFATc3 上调，但核定位减少。向髓质集合管 mIMCD3 细胞中敲低 ILK，并转染报告质粒。药理激活剂或抑制剂确定了 ILK 活性对 NFATc/AP-1 依赖性增加 AQP2 转录的影响。最后，在 Col I 上培养的 mIMCD3 显示出 ILK/GSK3β/NFATc/AQP2 轴的活性降低，表明该途径是治疗 NDI 的潜在治疗靶点。
