Yang Yan, Shi Wanxin, Li Cuili, Li Luan, Li Jiaying, Chen Yingwen, Shi Qingying, Xie Zhiyong, Wang Mengjie, Zhang Hong, Zhao Xingchen, Chen Yuanhan, Li Ruizhao, Liu Shuangxin, Ye Zhiming, Zhang Li, Liang Xinling
The Second School of Clinical Medicine, Southern Medical University, Guangzhou, 510515, China; Department of Nephrology, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510080, China.
Department of Nephrology, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510080, China.
Biochem Biophys Res Commun. 2023 May 14;656:104-114. doi: 10.1016/j.bbrc.2023.02.069. Epub 2023 Mar 11.
Podocyte injury is a crucial factor in the pathogenesis of diabetic kidney disease (DKD), and finding potential therapeutic interventions that can mitigate podocyte injury holds significant clinical relevance. This study was to elucidate the role of growth associated protein-43(Gap43) in podocyte injury of high glucose (HG). We confirmed the expression of Gap43 in human glomerulus and found that Gap43 expression was downregulated in podocytes of patients with DKD and HG-treated podocytes in vitro. Gap43 knockdown in podocytes promoted podocyte apoptosis, increased migration ability and decreased nephrin expression, while overexpression of Gap43 markedly suppressed HG-induced injury. Moreover, the increased expression and activity of calcineurin (CaN) were also abrogated by overexpression Gap43 in HG. Pretreatment with a typical CaN inhibitor FK506 in Gap43 knockdown podocytes restored the injury. Mechanistically, co-immunoprecipitation experiments suggested that Gap43 could bind to calmodulin (CaM). Pull-down assay further demonstrated that Gap43 and CaM directly interacts with each other via amino acids 30-52 of Gap43 and amino acids 133-197 of CaM. In addition, we also identified Pax5 as potential transcription inhibitor factor mediating Gap43 expression. In conclusion, the study indicated that the Gap43/CaM-CaN pathway may be exploited as a promising therapeutic target for protecting against podocyte injury in high glucose.
足细胞损伤是糖尿病肾病（DKD）发病机制中的关键因素，寻找能够减轻足细胞损伤的潜在治疗干预措施具有重要的临床意义。本研究旨在阐明生长相关蛋白43（Gap43）在高糖（HG）诱导的足细胞损伤中的作用。我们证实了Gap43在人肾小球中的表达，并发现DKD患者的足细胞以及体外高糖处理的足细胞中Gap43表达下调。足细胞中Gap43基因敲低会促进足细胞凋亡，增加迁移能力并降低nephrin表达，而Gap43过表达则显著抑制高糖诱导的损伤。此外，高糖环境中Gap43过表达还可消除钙调神经磷酸酶（CaN）表达和活性的增加。在Gap43基因敲低的足细胞中用典型的CaN抑制剂FK506预处理可恢复损伤。机制上，免疫共沉淀实验表明Gap43可与钙调蛋白（CaM）结合。下拉实验进一步证明Gap43和CaM通过Gap43的30 - 52位氨基酸和CaM的133 - 197位氨基酸直接相互作用。此外，我们还确定Pax5是介导Gap43表达的潜在转录抑制因子。总之，该研究表明Gap43/CaM - CaN途径有望成为保护高糖环境下足细胞损伤的治疗靶点。
