Podocyte apoptosis is a major mechanism that leads to proteinuria in many chronic kidney diseases. However, the concert mechanisms that cause podocyte apoptosis in these kidney diseases are not fully understood. The Rho family of small GTPases has been shown to be required in maintaining podocyte structure and function. Recent studies have indicated that podocyte-specific deletion of Cdc42 in vivo, but not of RhoA or Rac1, leads to congenital nephrotic syndrome and glomerulosclerosis. However, the underlying cellular events in podocyte controlled by Cdc42 remain unclear. Here, we assessed the cellular mechanisms by which Cdc42 regulates podocyte apoptosis. We found that the expression of Cdc42 and its activity were significantly decreased in high glucose-, lipopolysaccharide- or adriamycin-injured podocytes. Reduced Cdc42 expression in vitro and in vivo by small interfering RNA and selective Cdc42 inhibitor ML-141, respectively, caused podocyte apoptosis and proteinuria. Our results further demonstrated that insufficient Cdc42 or Nwasp, its downstream effector, could decrease the mRNA and protein expression of YAP, which had been regarded as an anti-apoptosis protein in podocyte. Moreover, our data indicated that the loss of stress fibers caused by Cdc42/Nwasp deficiency also decreased Yes-associated protein (YAP) mRNA and protein expression, and induced podocyte apoptosis. Podocyte apoptosis induced by Cdc42/Nwasp/stress fiber deficiency was significantly inhibited by overexpressing-active YAP. Thus, the Cdc42/Nwasp/stress fibers/YAP signal pathway may potentially play an important role in regulating podocyte apoptosis. Maintaining necessary Cdc42 would be one potent way to prevent proteinuria kidney diseases.

Studies have shown that stress such as hypoxia, chemotherapy, radiotherapy can lead to polyploidization of tumor cells, which play an important role in tumor heterogeneity and malignant phenotype. Paclitaxel (PTX) treatment promoted polyploid cancer cells (PCCs) formation, and miR-378d is sharply reduced in PCCs of esophageal squamous cell carcinomas (ESCC) cells, but miR-378d participation PCCs formation and the impact on the biological behavior of ESCC remains unclear. We analyzed the PCCs formation and biological behavior of ESCC cells in vivo and in vitro, and the related proteins regulated by miR-378d. Results showed that miR-378d expression was associated with good prognosis in ESCC patients. miR-378d inhibition promoted PCCs formation, heterogenicity, chemo-resistance, monoclonal formation, EMT, migration, invasion, stemness and metastasis of ESCC cells. miR-378d can target downregulated AKT1, and inactivating the AKT-β-catenin signaling pathway, miR-378d and AKT can also regulated RhoA expression. AKT and RhoA regulated polyploidization and depolyploidization. Therefore, miR-378d expression is a good prognostic factor of ESCC patients and regulates polyploidization and malignant phenotype of tumor cells through AKT and RhoA.