CXCR3 knockdown protects against high glucose-induced podocyte apoptosis and inflammatory cytokine production at the onset of diabetic nephropathy.

Chemokines and their receptors play an important role in the pathogenesis of acute and chronic diabetic nephropathy (DN). However, their expression pattern and function in glomerular podocytes have not been investigated as of yet. In the present study, we investigated whether CXCR3 could protect podocytes from high glucose-induced apoptosis and inflammatory cytokine production and explored the possible mechanism. Cell viability, cell cycle and apoptosis were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry, respectively. The level of intracellular reactive oxygen species (ROS) and mitochondrial membrane potential (∆Ψm) was measured using a dichlorofluorescein diacetate (DCFH-DA) ortetrechloro-tetraethylbenzimidazol carbocyanine iodide (JC-1) fluorescent probe, respectively. Quantitative real-time PCR was used to determine the gene expression of CXCR3. Western blots were carried out for the related protein expression in podocytes, including CXCR3, Nephrin, Podocin, Bcl-2, Bax, and Caspase-3. Firstly, we found that CXCR3 expression was significantly up-regulated and cell viability was decreased in high glucose (HG)-treated mouse podocytes in a dose-dependent manner. Secondly, knockdown of CXCR3 in mouse podocytes significantly suppressed HG-induced viability decrease, cell cycle arrest, ROS generation and ∆Ψm reduction. Moreover, knockdown of CXCR3 reduced the podocytes injury in cell apoptosis and inflammation through increasing the expression of Nephrin, Podocin and Bcl-2, and decreasing the expression of Bax and Caspase-3. In conclusion, CXCR3 knockdown protected podocytes from HG-induced apoptosis and inflammation , suggesting that inhibition of CXCR3 may have a therapeutic potential in DN treatment.