Wen Yueqiang, Liu Lingling, Zhou Peilan, Li Huiyuan, Wang Zebin, Zhang Yajie, Liang Jianbo
a Department of Nephrology , The 2nd Affiliated Hospital of Guangzhou Medical University , Guangzhou , P.R. China ;
b Department of General Medicine , The 3rd Affiliated Hospital of Sun Yat-Sen University , Guangzhou , P.R. China.
Ren Fail. 2016;38(4):564-70. doi: 10.3109/0886022X.2016.1148936. Epub 2016 Feb 24.
Podocyte injury is a vital factor, which induces massive proteinuria. Studies have shown that tacrolimus (TAC) protected podocyte via stabilizing cytoskeleton. Our latest study indicates that calcineurin binding protein 1 (Cabin1) undergoes nuclear translocation during podocytes injury. Whether TAC targets on Cabin1 during podocyte injury is still not clear. This study establishes non-immunological proteinuric model. To observe the effect of the treatment of TAC on Cabin1 expression in 5/6 nephrectomized rats. Sprague-Dawley rats were injected with TAC (0.2 mg/kg/day) for 4-8 weeks after 5/6 nephrectomy. Then, rats were sacrificed in the eighth week after operation, renal tissues were processed for morphological studies under light and electrical microscope. Cabin1 expression and distribution were detected by western blot and indirect immunofluorescence staining. In 5/6 nephrectomized rats, urinary protein excretion reached 90.2 ± 30.1 mg/24 h, glomerular sclerosis index and tubulointerstitial fibrosis score were significantly increased, and widespread of podocyte foot processes fusion was found. Moreover, Cabin1 protein expression was markedly increased, and its distribution became much more obviously in podocytes nuclei. In TAC treated rats, urinary protein excretion significantly decreased (44.9 ± 22.5 mg/24 h), glomerular sclerosis and tubulointerstitial fibrosis were alleviated, and podocyte foot processes fusion was inhibited. Furthermore, TAC alleviated the increased protein expression and abnormal distribution of Cabin1. In conclusion, TAC restores podocyte injury and stabilizes the expression of Cabin1. Cabin1 may become a new target to demonstrate the mechanism of TAC in podocyte injury.
足细胞损伤是导致大量蛋白尿的关键因素。研究表明，他克莫司（TAC）通过稳定细胞骨架来保护足细胞。我们最新的研究表明，钙调神经磷酸酶结合蛋白1（Cabin1）在足细胞损伤过程中发生核转位。TAC在足细胞损伤过程中是否靶向Cabin1尚不清楚。本研究建立了非免疫性蛋白尿模型。旨在观察TAC治疗对5/6肾切除大鼠Cabin1表达的影响。对Sprague-Dawley大鼠进行5/6肾切除术后，注射TAC（0.2mg/kg/天），持续4-8周。然后，在术后第8周处死大鼠，取肾组织进行光镜和电镜下的形态学研究。通过蛋白质免疫印迹法和间接免疫荧光染色检测Cabin1的表达和分布。在5/6肾切除大鼠中，尿蛋白排泄量达到90.2±30.1mg/24h，肾小球硬化指数和肾小管间质纤维化评分显著增加，且发现广泛的足细胞足突融合。此外，Cabin1蛋白表达明显增加，其在足细胞核中的分布变得更加明显。在TAC治疗的大鼠中，尿蛋白排泄量显著降低（44.9±22.5mg/24h），肾小球硬化和肾小管间质纤维化得到缓解，足细胞足突融合受到抑制。此外，TAC减轻了Cabin1蛋白表达的增加和异常分布。总之，TAC可恢复足细胞损伤并稳定Cabin1的表达。Cabin1可能成为阐明TAC在足细胞损伤中作用机制的新靶点。
