Odense University Hospital, and University of Southern Denmark, Institute of Molecular Medicine, Cardiovascular and Renal Research, Denmark.
Arch Biochem Biophys. 2011 Oct;514(1-2):44-9. doi: 10.1016/j.abb.2011.07.011. Epub 2011 Jul 23.
It is unknown whether extracellular calcium may regulate the expression of transient receptor potential canonical type 3 (TRPC3) channels in patients with chronic kidney disease. Using quantitative in-cell Western assay we compared the expression of TRPC3 channel protein in monocytes from 20 patients with chronic kidney disease and 19 age- and sex-matched healthy control subjects. TRPC3 channels were identified by immunoblotting using specific antibodies and TRPC3 protein was further confirmed by mass spectrometry. We observed a significant increase of TRPC3 channel protein expression in patients with chronic kidney disease compared to healthy control subjects (normalized expression, 0.42±0.06 vs. 0.19±0.03; p<0.01). Expression of TRPC3 was significantly inversely correlated with estimated glomerular filtration rates (Spearman r=-0.41) or serum calcium concentration (Spearman r=-0.34). During a hemodialysis session serum calcium concentrations significantly increased, whereas the expression of TRPC3 channels and calcium influx significantly decreased. In vitro studies confirmed that higher calcium concentrations but not magnesium, barium nor sodium concentrations significantly decreased TRPC3 expression in human monocytes. This study indicates that reduced extracellular calcium concentrations up-regulate TRPC3 channel protein expression in patients with chronic kidney disease.
目前尚不清楚细胞外钙是否可以调节慢性肾脏病患者瞬时受体电位经典型 3 (TRPC3) 通道的表达。我们使用定量细胞内 Western 检测法比较了 20 名慢性肾脏病患者和 19 名年龄和性别匹配的健康对照者单核细胞中 TRPC3 通道蛋白的表达。通过使用特异性抗体进行免疫印迹鉴定 TRPC3 通道，并用质谱法进一步证实 TRPC3 蛋白。与健康对照组相比，我们观察到慢性肾脏病患者的 TRPC3 通道蛋白表达显著增加（归一化表达，0.42±0.06 对 0.19±0.03；p<0.01）。TRPC3 的表达与估计的肾小球滤过率（Spearman r=-0.41）或血清钙浓度（Spearman r=-0.34）呈显著负相关。在血液透析过程中，血清钙浓度显著升高，而 TRPC3 通道和钙内流的表达显著降低。体外研究证实，较高的钙浓度而非镁、钡或钠浓度可显著降低人单核细胞中 TRPC3 的表达。本研究表明，细胞外钙浓度降低可上调慢性肾脏病患者的 TRPC3 通道蛋白表达。
