Kong Weiying, Haschler Timo Nicolas, Nürnberg Bernd, Krämer Stephanie, Gollasch Maik, Markó Lajos
Experimental and Clinical Research Center (ECRC), Charité Medical Faculty and Max-Delbrück Center for Molecular Medicine, Berlin, Germany.
Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany.
Cell Physiol Biochem. 2019;52(6):1484-1502. doi: 10.33594/000000103.
BACKGROUND/AIMS: The transient receptor potential cation channel subfamily C member 6 (TRPC6) is a Ca-permeable nonselective cation channel and has received recent attention because of its capability to promote chronic kidney disease (CKD). The aims of this study were (i) to examine whether deletion of TRPC6 impacts on renal fibrosis and inflammatory cell infiltration in an early CKD model of unilateral ureter obstruction (UUO) in mice; and (ii) whether TRPC6-deficiency as well as UUO affect the regulation of TRPC expression in murine kidneys.
Wild-type (WT), Trpc6-knockout (Trpc6) and New Zealand obese (NZO) mice underwent sham operation or unilateral ureteral obstruction (UUO). The kidneys were harvested 7 days after surgery. We examined renal fibrosis and inflammatory cell infiltration by histological and immunohistochemical staining. The mRNA expression of TRPC members and markers of fibrosis and inflammation in kidney were assessed by using real-time quantitative reverse transcription PCR.
Histological and immunohistochemical analyses revealed less inflammatory cell infiltration (F4/80 and CD3) in UUO kidneys of Trpc6 mice compared to UUO kidneys of WT mice as well as less fibrosis. Genomic deletion of TRPC6 also affected the expression of pro-fibrotic genes in UUO Trpc6 kidneys compared to UUO WT kidneys while the expression of pro-inflammatory genes did not differ. UUO caused marked up-regulation of Trpc6 and down-regulation of Trpc1 mRNA in kidneys of WT and NZO mice. Trpc3 mRNA expression was significantly elevated in kidneys of Trpc6 mice underwent UUO while the levels did not change in kidneys of neither WT nor in NZO mice underwent UUO.
TRPC6 contributes to renal fibrosis and immune cell infiltration in the UUO mouse model. Therefore, inhibition of TRPC6 emerges as a promising novel therapeutic strategy for treatment of chronic kidney failure in chronic obstructive nephropathy. However, confounding genomic and non-genomic effects of other TRPC channels should be taken into consideration to fully comprehend the renoprotective potential of targeting TRPC6 therapeutically under chronic kidney damaging conditions.
背景/目的：瞬时受体电位阳离子通道C亚家族成员6（TRPC6）是一种可通透钙离子的非选择性阳离子通道，因其在促进慢性肾脏病（CKD）发生发展中的作用，近年来受到广泛关注。本研究旨在：（i）在小鼠单侧输尿管梗阻（UUO）早期CKD模型中，检测TRPC6基因敲除是否影响肾纤维化和炎性细胞浸润；（ii）TRPC6基因缺陷以及UUO是否影响小鼠肾脏中TRPC表达的调控。
野生型（WT）、Trpc6基因敲除（Trpc6）和新西兰肥胖（NZO）小鼠接受假手术或单侧输尿管梗阻（UUO）。术后7天取肾脏。通过组织学和免疫组化染色检测肾纤维化和炎性细胞浸润情况。采用实时定量逆转录PCR评估肾脏中TRPC成员的mRNA表达以及纤维化和炎症标志物。
组织学和免疫组化分析显示，与WT小鼠的UUO肾脏相比，Trpc6小鼠的UUO肾脏中炎性细胞浸润（F4/80和CD3）减少，纤维化程度减轻。与WT小鼠的UUO肾脏相比，TRPC6基因缺失也影响了Trpc6小鼠UUO肾脏中促纤维化基因的表达，而促炎基因的表达无差异。UUO导致WT和NZO小鼠肾脏中Trpc6明显上调，Trpc1 mRNA下调。接受UUO的Trpc6小鼠肾脏中Trpc3 mRNA表达显著升高，而接受UUO的WT和NZO小鼠肾脏中该水平未发生变化。
TRPC6在UUO小鼠模型中促进肾纤维化和免疫细胞浸润。因此，抑制TRPC6有望成为治疗慢性梗阻性肾病所致慢性肾衰竭的新型治疗策略。然而，在慢性肾脏损伤条件下，为全面理解靶向TRPC6治疗的肾脏保护潜力，应考虑其他TRPC通道复杂的基因组和非基因组效应。
