Oxalate induces phosphatidylserine externalization, apoptosis, and crystal-cell adhesion in renal tubular epithelial cells through the ROS-ADAM17-Notch1 axis

Abstract

Abstract Background Oxalate salts induce reactive oxygen species (ROS) generation, leading to phosphatidylserine (PS) externalization from renal tubule epithelial cells and the development of kidney stone. This research investigated the roles of ADAM17 (A Disintegrin and Metalloproteinase 17) and the Notch1 signaling pathway in oxalate-induced cell crystal adhesion through ROS-mediated mechanisms. Methods We treated HK-2 with sodium oxalate to establish a model of damage. ROS were measured using DCFH-DA fluorescence, and apoptosis and PS externalization were measured using flow cytometry. QPCR was applied to evaluate the mRNA of ADAM17 and Notch1, while western blot analysis was employed to assess their corresponding protein levels. Crystal adhesion assays were used to assess cell adherence to calcium oxalate crystals. The function of ADAM17 in oxalate-induced injury was examined by siRNA-mediated knockdown. Results Exposure to oxalate significantly elevated ROS generation, apoptotic incidence, PS externalization, and crystal adhesion in HK-2 cells. Moreover, oxalate exposure upregulated ADAM17 expression and activated the Notch1 signaling pathway. Antioxidant treatment reduces ADAM17 expression and inhibits Notch1 pathway activation. ADAM17 knockdown partially rescued ROS-induced apoptosis and PS externalization, reduced crystal adhesion, and suppressed Notch1 signaling. Conclusion Oxalate triggers apoptosis, PS externalization, and crystal cell adhesion in renal tubular epithelial cells through the ROS-ADAM17-Notch1 axis.