Effect of calcium oxalate stone on protein expression profiles of human proximal renal tubular epithelial cells

Abstract

Objective To investigate the effect of calcium oxalate crystals on the protein expression profiles in human proximal renal tubular epithelial cells, screen differentially expressed proteins and explore the relationship between kidney stones and renal injury. Methods The clinical kidney stone samples were analyzed and chose to culture with human proximal tubular epithelial cells HK-2. The cell total protein was extracted and qualified by SDS-PAGE. The protein concentration was determined by BSA method, and the difference of protein expression profiles between the experimental group and the control group were screened by TMT-labeled quantitative proteomics analysis. Cluster analysis, GO enrichment analysis and differential gene-related interaction network analysis were performed by bioinformatics method. Results The calcium oxalate crystal showed obvious cytotoxicity to HK-2 cells, and the cell growth slowed down and caused cell shape change significantly. The TMT-labeled quantitative proteomic analysis showed that after treatment with calcium oxalate crystals, a total of 1 141 proteins were differentially expressed in HK-2 cells, of which 699 were up-regulated and 442 were down-regulated. Bioinformatics analysis indicated that these differential proteins played important roles in extracellular complexes, organelles and various cytological processes, differential protein co-expression network analysis demonstrated that proteins involved in cytoskeletal maintenance (such as ACTB, CFL1) and several specific functions such as secretion and capping (MYH9, MYH14) were most closely related. Conclusion Calcium oxalate crystal has a significant effect on protein expression profiling in human renal epithelial cells, and these differentially expressed protein molecules may be involved in the formation of kidney stones and kidney injury. Key words: Calcium oxalate crystal; Kidney stones; Protein expression profile; Renal epithelial cells; Cluster analysis