1,25 (OH) 2D3/VDR MEDIATES KIDNEY STONE FORMATION BY REGULATING THE BMP2 SIGNALING PATHWAY AND OPN EXPRESSION

Yongqiang Liu^*

Department of Urology, Traditional Chinese Medical Hospital of Lianyungang City, Lianyungang 222000, PR China

Objective: To analyze the role of 1,25(OH)2D3/VDR in renal stone formation by regulating the bone morphogenetic protein 2 (BMP2) signaling pathway and osteopontin (OPN) expression. 

Methods: Renal tubular epithelial cells were cultured in vitro and divided into a control group, a VDR silencing group, and a silencing control group. The cells were treated with normal saline, VDR lentivirus vector, and empty virus vector respectively. The cells were collected for detection at 6, 12, 24, 48, and 96h after cell treatment. 1,25 (OH) 2D3 was added into the cell culture medium and incubated for 6, 12, 24, 48, and 96h to collect cells for detection. Calcification was detected at different time points; gene and protein expression of bone-related factors were detected by real-time quantitative PCR and Western blot. 

Results: The calcification level of renal tubular epithelial cells in the control group was the same as that of the silent control group. The calcification level of renal tubular epithelial cells in the VDR silencing group was significantly lower than that of the control group and the silencing control group at 12h, 48h and 96h (P<0.05). After 96 hours of VDR gene silencing, BMP2, Runx2, Osterix, and OPN mRNA in renal tubular epithelial cells in the silencing VDR group were significantly lower than those in the control group and the silencing control group (P<0.05). In the 1,25 (OH) 2D3 group, there were more mineral deposition cells, and the color was darker; in the control group, only a small amount of mineral deposition appeared in the cytoplasm, and the color was lighter. When 1,25 (OH) 2D3 was co-incubated with renal tubular epithelial cells for 12h, the intracellular calcium and phosphorus deposition increased gradually, and the difference was statistically significant at 48h and 96h compared with the control group (P<0.05). BMP2, Runx2, Osterix, and OPN mRNA in renal tubular epithelial cells in the 1,25 (OH) 2D3 group were significantly higher than those in the control group and the silent control group (P<0.05). 

Conclusion: 1,25 (OH) 2D3/VDR plays an important regulatory role in the formation of renal calculi, and its related mechanism may be realized by regulating the BMP2 signaling pathway and OPN expression.