Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
Proteomics. 2018 Apr;18(8):e1800008. doi: 10.1002/pmic.201800008. Epub 2018 Apr 2.
Our previous expression study has reported a set of proteins with altered levels in renal tubular cells after exposure to calcium oxalate monohydrate (COM) crystals, which are the main composition of kidney stones. However, their functional significance remained largely unknown. In this study, protein network analysis revealed that the significantly altered proteins induced by COM crystals were involved mainly in three main functional networks, including i) cell proliferation and wound healing; ii) oxidative stress and mitochondrial function; and iii) cellular junction complex and integrity. Cell proliferation and wound healing assays showed that the COM-treated cells had defective proliferation and tissue healing capability, respectively. Oxyblot analysis demonstrated accumulation of the oxidized proteins, whereas intracellular ATP level was significantly increased in the COM-treated cells. Additionally, level of zonula occludens-1 (ZO-1), a tight junction protein, was significantly decreased, consistent with the significant declines in transepithelial resistance (TER) and level of RhoA signaling molecule in the COM-treated cells. These findings indicate significant perturbations in mitochondrial and oxidative stress axis that cause defective cell proliferation, tissue healing capability, junctional protein complex, and cellular integrity of renal tubular epithelial cells exposed to COM crystals that may play important roles in kidney stone pathogenesis.
我们之前的表达谱研究报道了在草酸钙一水合物 (COM) 晶体暴露后肾小管细胞中一组蛋白水平发生改变的情况，COM 晶体是肾结石的主要成分。然而，其功能意义在很大程度上仍然未知。在这项研究中，蛋白质网络分析表明，COM 晶体诱导的显著改变的蛋白主要涉及三个主要的功能网络，包括 i）细胞增殖和伤口愈合；ii）氧化应激和线粒体功能；和 iii）细胞连接复合物和完整性。细胞增殖和伤口愈合实验表明，COM 处理的细胞增殖和组织愈合能力分别有缺陷。Oxyblot 分析表明氧化蛋白的积累，而 COM 处理的细胞内 ATP 水平显著增加。此外，紧密连接蛋白 zonula occludens-1 (ZO-1) 的水平显著降低，与 COM 处理的细胞中上皮细胞间电阻 (TER) 和 RhoA 信号分子水平的显著下降一致。这些发现表明，暴露于 COM 晶体的肾小管上皮细胞中线粒体和氧化应激轴的显著紊乱导致细胞增殖、组织愈合能力、连接蛋白复合物和细胞完整性缺陷，可能在肾结石发病机制中发挥重要作用。
