The Studuy Of Endoplasmic Reticulum Stress Induced By Calcium Oxalate Crystal In Renal Tubular Epithelial Cells

ObjectiveEndoplasmic reticulum is a place where the protein is post-translationally modified.Endoplasmic reticulum stress is considered as the third signaling pathway that induces cell apoptosis.It is an important way to induce a variety of chronic and metabolic diseases.This project examines the relationship between the formation of kidney stones and endoplasmic reticulum stress.MethodsIn this study,HK-2 human renal tubular epithelial cells were exposed with 100μg/mL calcium oxalate crystals for 3h,6h,12h and 24h,Oh as the control group.Real-time PCR was used to detect the expression of BIP/GRP78,CHOP,PERK,JNK,P38 and Caspase-3,and the expression of BIP/GRP78,CHOP,p-PERK,p-JNK,p-P38,XBP1,Cleaved-Caspase-3 and Caspase-12 were detected by Western blot in 48 hours and 0 hour.The apoptosis was detected at 24h using the TUNEL method.ResultsAfter stimulation of HK-2 cells with 100 μg/mL calcium oxalate,the mRNA expression of ER stress marker gene,BIP/GRP78 and CHOP,was increased.The expression of PERK,JNK and P38 in the endoplasmic reticulum stress pathway was increased.When the HK-2 cells were stimulated with calcium oxalate for 6 hours,the expression of BIP/GRP78 protein was increased,and the expression of CHOP protein was significantly higher than that of the control group at 12 hours after exposure.The expression of P-PERK,P-JNK,P-P38 and XBP1 proteins were increased at 3 hours,3 hours,6 hours and 3 hours compared to the control group.The western blot results were consistent with Real-time RCR results.TUNEL detection showed that apoptosis occurred at 24 hours after crystals exposure.The rate of apoptosis cell is about 25%.The expression of endoplasmic reticulum stress specific protein,Caspase-12,and Cleaved-Caspase-3 were increased using western blot.ConclusionsFor the first time,we found that calcium oxalate crystals induce endoplasmic reticulum stress in renal tubular epithelial cells,the apoptosis of renal tubular cells induced by crystallization is caused by the mitochondrial apoptosis pathway and the endoplasmic reticulum apoptosis pathway.These findings suggest that endoplasmic reticulum stress may be an important pathogenesis of the formation of kidney stones.