CD248, targeted by veratramine and neobavaisoflavone, mediates pathological changes of renal tubular epithelial cells induced by high glucose.

BACKGROUND: Epithelial-mesenchymal transition (EMT) of tubular epithelial cells are one of the major pathological changes of diabetic nephropathy (DN). Cluster of differentiation 248 (CD248) has been reported to be associated with fibrosis after kidney injury. The aim of this study was to investigate the mechanism of CD248 in DN and its targeted compounds. MATERIALS AND METHODS: Virtual screening, molecular docking and Cellular thermal shift assays were used to explore potential small molecule compounds targeting CD248. In vitro DN model was established by treating human proximal renal tubular epithelial cell line HK-2 with high glucose (HG), and db/db mice were used as the animal model. siRNA transfection was used to knockdown CD248 in HK-2 cells, and HK-2 cells and the animals were treated with veratramine (VER) or neobavaisoflavone (NBIF). qPCR was used to detect the mRNA expression of CD248, tumor necrosis factor-α (TNF-α), interleukin (IL)-6 (IL-6), and IL-1β. Western blot was used to assess protein expression level of CD248, EMT-associated proteins, fibrosis markers, and TGF-β1/Smads pathway-associated proteins. CCK-8 assay and flow cytometry were used to detect cell viability and apoptosis, respectively. Histopathological and various biochemical indicators were used to assess renal injury in animals. RESULTS: CD248 was significantly up-regulated in HG-induced HK-2 cells. CD248 knockdown inhibited HG-induced cell proliferation inhibition, apoptosis and inflammatory response. HG stimulation significantly reduced the protein expression level of E-cadherin in HK-2 cells, and increased the expression levels of vimentin, α-smooth muscle actin (α-SMA), collagen I, collagen IV, fibronectin, TGF-β1, p-Smad2, p-Smad3, and Smad4, while CD248 knockdown reversed these effects. In addition, VER and neobavaisoflavone were found to bind with CD248, and they inhibited HG-induced apoptosis, inflammation, EMT and extracellular matrix synthesis in HK-2 cells, and ameliorate the renal injury of db/db mice. VER and NBIF also inhibited HG-induced activation of TGF-β1/Smads axis. CONCLUSION: CD248 participates in HG-induced EMT of renal tubular epithelial cells and renal fibrosis by regulating TGF-β1/Smads pathway, and VER and NBIF are two potential natural drugs which targets it to ameliorate DN.