TMT-based proteomic analysis reveals the effects of chloroquine on human podocytes

Chloroquine (CQ) is an antimalarial drug widely used in rheumatic, immunological and infectious diseases. CQ is also a well-known autophagy inhibitor. It slows the progression of renal injury in patients with rheumatology diseases. Long-term CQ treatment could also damage podocytes which are highly differentiated cells wrapping the glomerular capillary to maintain renal filtration. However, the related underlying mechanism remains unclear. The effects of CQ treatment on podocytes need to be elucidated. Our results showed that CQ diminished cell motility and disrupted actin cytoskeleton in human podocytes in vitro. Totally 210 up-regulated and 67 down-regulated differentially expressed proteins (DEPs) were identified after CQ treatment in podocytes by using tandem mass tag (TMT)-labeled quantitative proteomics analysis. Gene Ontology (GO) analysis revealed that proteins mainly functioned in cell motility, cell adhesion, localization of cells and response to external stimulus. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment showed that DEPs were predominantly associated with lysosome, cell adhesion molecules (CAMs) and cytokine-cytokine receptor interaction. Protein-protein interaction (PPI) analysis revealed that syndecan-4 was the core protein in regulating podocyte adhesion among differentially expressed CAMs. Moreover, activated RhoA, Cdc42 and Rac1 decreased after CQ treatment. Taken together, our findings suggested that CQ could alter the stability of podocyte cytoskeleton. Proteomic analysis revealed important molecules for understanding the effects of CQ on human podocytes.