Presentation Authors: Haoran Liu, Kun Tang, Tao Ye, Xiaoqi Yang, Kehua Jiang*, Fa Sun, Wuhan, China, People's Republic of
Introduction: Recently, the supplemental intake of high-dose vitamin C was shown to be significantly associated with a higher risk of calcium oxalate (CaOx) kidney stone in men, but not among women, This study aimed to elucidate whether AR could promote the vitamin C induced CaOx kidney stones.
Methods: Crystals deposition in mouse kidneys were examined by polarized light optical microphotography and pizzolato staining.High performance liquid chromatography was used to measure oxalate levels inÂ intracellular and extracellular.ChIP assay and luciferase assay demonstrated that AR suppressed TXNRD1 and GLRX2 expression via directly regulating miR-182. Protein and mRNA expression were examined by WB and qPCR.
Results: To elucidate the effect of vitamin C supplementation on kidney CaOx crystals formation, we intraperitoneally injected vitamin C in the glyoxylate-induced kidney CaOx mouse model.Using microCT, polarized light optical microphotography and Pizzolato staining in the kidneys, a significant increase in the CaOx crystals deposition in the high-dose vitamin C group was observed. We found that DHT significantly induces miR-182 and suppress TXNRD1 and GLRX2 expression in HL-7702 and HK-2 cells. Additionally, the intracellular and extracellular oxalate levels were shown to increase with the increase vitamin C levels. Conversely, oxalate levels were lower in the AR-knockout HL-7702 cells. ChIP assays demonstrated the AR-positive transcriptional activation of miR-182. Using luciferase assays, miR-182 was shown to target the 3â€²-untranslated region (UTR) of TXNRD1 and GLRX2, leading to a decrease in their expression in vitro. Their downregulation induced an increase in vitamin C metabolization to oxalate and oxidative stress induced by CaOx crystals. Additionally, AR and miR-182 inactivation led to the suppression of CaOx crystal formation through the regulation of vitamin C metabolism and oxidative stress in vitro and in vivo.
Conclusions: These findings, for the first time, demonstrated that AR promotes kidney CaOx stone formation and deposition by regulating oxalate biosynthesis from vitamin C and the development of oxidative stress-induced kidney injuries through a newly-identified AR-miR-182-TXNRD1/GLRX2 pathway in vivo and in vitro.
Source of Funding: This project was supported by the National Natural Science Foundation of China (81370805, 81470935, 81500534, 81602236, 81670645).