Zhejiang Key Laboratory of Intelligent Cancer Biomarker Discovery and Translation, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325035, China.
Department of Laboratory Medicine, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325035, China.
Cell Biol Toxicol. 2024 Oct 9;40(1):86. doi: 10.1007/s10565-024-09929-7.
Renal interstitial fibrosis (RIF) is a common feature of chronic kidney diseases (CKD), with epithelial-mesenchymal transition (EMT) being one of its important mechanisms. S100A2 is a protein associated with cell proliferation and differentiation, but its specific functions and molecular mechanisms in RIF remain to be determined.
S100A2 levels were evaluated in three mouse models, including unilateral ureteral obstruction (UUO), ischemia-reperfusion injury (IRI), and aristolochic acid nephropathy (AAN), as well as in TGF-β1- treated HK-2 cells and in kidney tissue samples. Furthermore, the role of S100A2 and its interaction with FoxO1 was investigated using RT-qPCR, immunoblotting, immunofluorescence staining, co-immunoprecipitation (Co-IP), transcriptome sequencing, and gain- or loss-of-function approaches in vitro.
Elevated expression levels of S100A2 were observed in three mouse models and TGF-β1-treated HK2 cells, as well as in kidney tissue samples. Following siRNA silencing of S100A2, exposure to TGF-β1 in cultured HK-2 cells suppressed EMT process and extracellular matrix (ECM) accumulation. Conversely, Overexpression of S100A2 induced EMT and ECM deposition. Notably, we identified that S100A2-mediated EMT depends on FoxO1. Immunofluorescence staining indicated that S100A2 and FoxO1 colocalized in the nucleus and cytoplasm, and their interaction was verified in Co-IP assay. S100A2 knockdown decreased TGF-β1-induced phosphorylation of FoxO1 and increased its protein expression, whereas S100A2 overexpression hampered FoxO1 activation. Furthermore, pharmacological blockade of FoxO1 rescued the induction of TGF-β1 on EMT and ECM deposition in S100A2 siRNA-treated cells.
S100A2 activation exacerbates interstitial fibrosis in kidneys by facilitating FoxO1-mediated EMT.
肾间质纤维化（RIF）是慢性肾脏病（CKD）的共同特征，上皮-间充质转化（EMT）是其重要机制之一。S100A2 是一种与细胞增殖和分化相关的蛋白质，但它在 RIF 中的具体功能和分子机制仍有待确定。
在单侧输尿管梗阻（UUO）、缺血再灌注损伤（IRI）和马兜铃酸肾病（AAN）三种小鼠模型中，以及在 TGF-β1 处理的 HK-2 细胞和肾组织样本中评估 S100A2 水平。此外，采用 RT-qPCR、免疫印迹、免疫荧光染色、共免疫沉淀（Co-IP）、转录组测序以及体外基因敲低或过表达等方法，研究 S100A2 的作用及其与 FoxO1 的相互作用。
在三种小鼠模型和 TGF-β1 处理的 HK2 细胞以及肾组织样本中，S100A2 的表达水平升高。用 S100A2 的 siRNA 沉默后，在培养的 HK-2 细胞中，TGF-β1 抑制 EMT 过程和细胞外基质（ECM）积累。相反，S100A2 的过表达诱导 EMT 和 ECM 沉积。值得注意的是，我们发现 S100A2 介导的 EMT 依赖于 FoxO1。免疫荧光染色表明 S100A2 和 FoxO1 在核和细胞质中共定位，Co-IP 实验验证了它们之间的相互作用。S100A2 敲低减少了 TGF-β1 诱导的 FoxO1 磷酸化，增加了其蛋白表达，而 S100A2 过表达阻碍了 FoxO1 的激活。此外，FoxO1 的药理学阻断挽救了 S100A2 siRNA 处理细胞中 TGF-β1 诱导的 EMT 和 ECM 沉积。
S100A2 的激活通过促进 FoxO1 介导的 EMT 加重肾脏间质纤维化。
