Inhibition of AT1R/IP3/IP3R-mediated Ca2+ release protects against calcium oxalate crystals-induced renal oxidative stress

Calcium oxalate (CaOx) stones are the most prevalent type of kidney stones. CaOx crystals can stimulate Reactive Oxygen Species (ROS) generation and induce renal oxidative stress to promote stone formation. Intracellular CA²⁺ is an important signaling molecule, and an elevation of cytoplasmic CA²⁺ levels could trigger oxidative stress. Our previous study has revealed that upregulation of Ang II/AT1R promoted renal oxidative stress during CaOx exposure. IP3/IP3R/CA²⁺ signaling pathway activated via Ang II/AT1R is involved in several diseases, but its role in stone formation has not been reported. Herein, we focus on the role of AT1R/IP3/IP3R-mediated CA²⁺ release in CaOx crystals-induced oxidative stress and explore whether inhibition of this pathway could alleviate renal oxidative stress. NRK-52E cells were exposed to CaOx crystals pretreated with AT1R inhibitor losartan or IP3R inhibitor 2-APB, and glyoxylic acid monohydrate-induced CaOx stone-forming rats were treated with losartan or 2-APB. The intracellular CA²⁺ levels, ROS levels, oxidative stress indexes, and the gene expression of this pathway were detected. Our results showed that CaOx crystals activated AT1R to promote IP3/IP3R-mediated CA²⁺ release, leading to increased cytoplasmic CA²⁺ levels. The CA²⁺ elevation was able to stimulate NOX2 and NOX4 to generate ROS, induce oxidative stress, and upregulate the expression of stone-related proteins. 2-APB and losartan reversed the referred effects, reduced CaOx crystals deposition and alleviated tissue injury in the rat kidneys. In summary, our results indicated that CaOx crystals promoted renal oxidative stress by activating the AT1R/IP3/IP3R/CA²⁺ pathway. Inhibition of AT1R/IP3/IP3R-mediated CA²⁺ release protected against CaOx crystals-induced renal oxidative stress. 2-APB and losartan might be promising preventive and therapeutic agents for the treatment of kidney stone disease.

2-APB; Ca(2+) release; Kidney stone diseases; Losartan; Oxidative stress.