Epithelial-mesenchymal Transition In Renal Tubular Epithelial Cells Research Articles

Inhibition of Ubiquitin-specific Protease 4 Attenuates Epithelial-Mesenchymal Transition of Renal Tubular Epithelial Cells via Transforming Growth Factor Beta Receptor Type I.

Ubiquitin-specific protease 4 (USP4) facilitates the development of transforming growth factor-beta 1 (TGF-β1)-induced epithelial-mesenchymal transition (EMT) in various cancer cells. Moreover, EMT of renal tubular epithelial cells (RTECs) is required for the progression of renal interstitial fibrosis. However, the role of USP4 in EMT of RTECs remains unknown. The present study aimed to explore the effect of USP4 on the EMT of RTECs as well as the involved mechanism. In established unilateral ureteral obstruction (UUO) rats and NRK-52E cells, immunohistochemistry and Western blot assays were performed. USP4 expression was increased significantly with obstruction time. In NRK-52E cells stimulated by TGF-β1, USP4 expression was increased in a time-dependent manner. In addition, USP4 silencing with specific siRNA indicated that USP4 protein was suppressed effectively. Meanwhile, USP4 siRNA treatment restored E-cadherin and weakened alpha smooth muscle actin (α-SMA) expression, indicating that USP4 may promote EMT. After treatment with USP4 siRNA and TGF-β1 for 24 h, the expression of TGF-β1 receptor type I (TβRI) was decreased. USP4 promotes the EMT of RTECs through upregulating TβRI, thereby facilitating renal interstitial fibrosis. These findings may provide a potential target of USP4 in the treatment of renal fibrosis.

Icariin inhibits epithelial mesenchymal transition of renal tubular epithelial cells via regulating the miR-122-5p/FOXP2 axis in diabetic nephropathy rats

Epithelial mesenchymal transition (EMT) of renal tubular epithelial cells (RTECs) dominates the pathology of diabetic nephropathy (DN). microRNAs (miRNAs) can influence the fate of DN via regulation of EMT. This study aimed to analyze the role of Icariin (ICA) in EMT of RTECs, hoping to provide theoretical basis for DN management. The DN rat model was established using streptozocin, followed by ICA treatment, histopathological observation, and detection of creatinine and blood urea nitrogen. In vitro cell models were established using high glucose (HG), followed by assessment of cell proliferation, apoptosis, and migration, and E-cadherin, α-SMA, miR-122-5p, and FOXP2 expressions. Cells were transfected with miR-122-5p mimics or si-FOXP2 for joint experiments with ICA. The targeting relationship between miR-122-5p and FOXP2 was verified. ICA repaired renal dysfunctions and glomerular structure abnormities of DN rats in a dose-dependent manner. In vitro, ICA improved proliferation while suppressed migration, apoptosis, and EMT of RTECs. miR-122-5p was up-regulated in DN rats and suppressed by ICA, and miR-122-5p targeted FOXP2. miR-122-5p up-regulation or FOXP2 down-regulation reversed the protective effects of ICA on HG-induced RTECs. Overall, our finding ascertained that ICA inhibited miR-122-5p to promote FOXP2 transcription, thereby attenuating EMT of RTECs and renal injury in DN rats.

The role of CDX2 in renal tubular lesions during diabetic kidney disease.

Renal tubules are vulnerable targets of various factors causing kidney injury in diabetic kidney disease (DKD), and the degree of tubular lesions is closely related to renal function. Abnormal renal tubular epithelial cells (RTECs) differentiation and depletion of cell junction proteins are important in DKD pathogenesis. Caudal-type homeobox transcription factor 2 (CDX2), represents a key nuclear transcription factor that maintains normal proliferation and differentiation of the intestinal epithelium. The present study aimed to evaluate the effects of CDX2 on RTECs differentiation and cell junction proteins in DKD. The results demonstrated that CDX2 was mainly localized in renal tubules, and downregulated in various DKD models. CDX2 upregulated E-cadherin and suppressed partial epithelial-mesenchymal transition (EMT), which can alleviate hyperglycemia-associated RTECs injury. Cystic fibrosis transmembrane conductance regulator (CFTR) was regulated by CDX2 in NRK-52E cells, and CFTR interfered with β-catenin activation by binding to Dvl2, which is an essential component of Wnt/β-catenin signaling. CFTR knockdown abolished the suppressive effects of CDX2 on Wnt/β-catenin signaling, thereby upregulating cell junction proteins and inhibiting partial EMT in RTECs. In summary, CDX2 can improve renal tubular lesions during DKD by increasing CFTR amounts to suppress the Wnt/β-catenin signaling pathway.