Li Qi, Veron Delma, Tufro Alda
Department of Pediatrics/Nephrology, New Haven, CT, United States.
Department of Cell and Molecular Physiology, Yale School of Medicine, New Haven, CT, United States.
Front Med (Lausanne). 2021 Jul 14;8:679518. doi: 10.3389/fmed.2021.679518. eCollection 2021.
The molecular pathogenesis of diabetic kidney disease progression is complex and remains unresolved. Rho-GAP was recently identified as a novel podocyte protein and a candidate gene for monogenic FSGS. Myo9A involvement in diabetic kidney disease has been suggested. Here, we examined the effect of diabetic milieu on Myo9A expression and . We determined that Myo9A undergoes S-nitrosylation, a post-translational modification dependent on nitric oxide (NO) availability. Diabetic mice with nodular glomerulosclerosis and severe proteinuria associated with doxycycline-induced, podocyte-specific gain-of-function showed markedly decreased glomerular Myo9A expression and S-nitrosylation, as compared to uninduced diabetic mice. Immortalized mouse podocytes exposed to high glucose revealed decreased expression, assessed by qPCR, immunoblot and immunocytochemistry, and reduced Myo9A S-nitrosylation (SNO-Myo9A), assessed by proximity link assay and biotin switch test, functionally resulting in abnormal podocyte migration. These defects were abrogated by exposure to a NO donor and were not due to hyperosmolarity. Our data demonstrate that high-glucose induced decrease of both expression and SNO-Myo9A is regulated by NO availability. We detected S-nitrosylation of Myo9A interacting proteins RhoA and actin, which was also altered by high glucose and NO dependent. RhoA activity inversely related to SNO-RhoA. Collectively, data suggest that dysregulation of SNO-Myo9A, SNO-RhoA and SNO-actin may contribute to the pathogenesis of advanced diabetic kidney disease and may be amenable to therapeutic targeting.
糖尿病肾病进展的分子发病机制复杂，尚未得到解决。Rho-GAP最近被鉴定为一种新型足细胞蛋白和单基因FSGS的候选基因。已有研究表明Myo9A参与糖尿病肾病。在此，我们研究了糖尿病环境对Myo9A表达的影响。我们确定Myo9A会发生S-亚硝基化，这是一种依赖于一氧化氮（NO）可用性的翻译后修饰。与未诱导的糖尿病小鼠相比，在强力霉素诱导的足细胞特异性功能获得的情况下，出现结节性肾小球硬化和严重蛋白尿的糖尿病小鼠肾小球Myo9A表达和S-亚硝基化明显降低。通过qPCR、免疫印迹和免疫细胞化学评估，暴露于高糖环境的永生化小鼠足细胞Myo9A表达降低，通过邻近连接分析和生物素开关试验评估，Myo9A的S-亚硝基化（SNO-Myo9A）减少，功能上导致足细胞迁移异常。这些缺陷通过暴露于NO供体而消除，且不是由于高渗引起的。我们的数据表明，高糖诱导的Myo9A表达和SNO-Myo9A的降低受NO可用性的调节。我们检测到Myo9A相互作用蛋白RhoA和肌动蛋白的S-亚硝基化，其也因高糖和NO依赖性而改变。RhoA活性与SNO-RhoA呈负相关。总体而言，数据表明SNO-Myo9A、SNO-RhoA和SNO-肌动蛋白的失调可能导致晚期糖尿病肾病的发病机制，并且可能适合作为治疗靶点。
