Targeting CC chemokine ligand (CCL) 20 by miR-143-5p alleviate lead poisoning-induced renal fibrosis by regulating interstitial fibroblasts excessive proliferation and dysfunction

Environmental lead contamination can cause chronic renal disease with a common clinical manifestation of renal fibrosis and constitutes a major global public health threat. Aberrant proliferation and extracellular matrix (ECM) accumulation in renal interstitial fibroblasts are key pathological causes of renal fibrosis. However, the mechanism underlying lead-induced kidney fibrosis remains unclear. The present study analyzed gene expression prolifes in lead acetate-treated primary mice renal interstitial fibroblasts and confirmed the aberrant expression of CC chemokine ligand (CCL) 20, one of the most obvious up-regulated genes. Analogously, lead acetate exposure dose-dependently increased CCL20 transcription, protein expression and release. Knockdown of CCL20 suppressed lead acetate-induced fibroblast proliferation, hydroxyproline contents, transforming growth factor-beta production and ECM-related protein (Collagen I and fibronectin) expression. Bioinformatics analysis predicted five top miRNAs targeting CCL20. Among them, miR-143-5p expression was dose-dependently decreased in lead acetate-treated fibroblasts. Mechanistically, miR-143-5p directly targeted CCL20. Elevation of miR-143-5p antagonized lead acetate-induced fibroblast proliferation, hydroxyproline and ECM-related protein expression, which were reversed by CCL20 overexpression. Additionally, CCL20 knockdown suppressed lead acetate-mediated Smad2/3 and AKT pathway activation. Notably, miR-143-5p overexpression attenuated the activation of the Smad2/3 and AKT pathway in lead acetate-exposed fibroblasts, which was counteracted by CCL20 elevation. miR-143-5p injection ameliorated renal fibrosis progression in mice in vivo. Thus, targeting CCL20 by miR-143-5p could alleviate renal fibrosis progression by regulating fibroblast proliferation and ECM deposition via the Smad2/3 and AKT signaling, providing a potential therapeutic target for environmental lead contamination-evoked fibrotic kidney disease.环境铅污染可引发以肾纤维化为常见临床表现的慢性肾病，是全球主要公共卫生威胁之一。肾间质成纤维细胞的异常增殖与细胞外基质（ECM）积聚是肾纤维化的核心病理诱因。然而，铅诱导肾纤维化的潜在分子机制仍未阐明。本研究对醋酸铅处理的原代小鼠肾间质成纤维细胞开展基因表达谱分析，证实CC趋化因子配体（CCL）20是上调幅度最为显著的基因之一。类似地，醋酸铅暴露可呈剂量依赖性提升CCL20的转录水平、蛋白表达量与分泌水平。敲低CCL20可抑制醋酸铅诱导的成纤维细胞增殖、羟脯氨酸含量升高、转化生长因子-β生成，以及ECM相关蛋白（I型胶原与纤连蛋白）的表达。生物信息学分析预测了5个靶向CCL20的核心miRNA。其中，miR-143-5p的表达在醋酸铅处理的成纤维细胞中呈剂量依赖性下调。机制研究表明，miR-143-5p可直接靶向结合CCL20。过表达miR-143-5p可拮抗醋酸铅诱导的成纤维细胞增殖、羟脯氨酸积累及ECM相关蛋白表达，该效应可被CCL20过表达逆转。此外，敲低CCL20可抑制醋酸铅介导的Smad2/3与AKT通路活化。值得注意的是，过表达miR-143-5p可减轻醋酸铅暴露下成纤维细胞中Smad2/3与AKT通路的活化，该作用可被CCL20过表达抵消。体内实验显示，注射miR-143-5p可改善小鼠肾纤维化进程。综上，miR-143-5p通过靶向CCL20，可经Smad2/3与AKT信号通路调节成纤维细胞增殖及ECM沉积，从而缓解肾纤维化进展，为环境铅污染诱发的纤维化肾病提供了潜在治疗靶点。