Isolation and identification of senescent renal tubular epithelial cells using immunomagnetic beads based on DcR2

Cell senescence plays a major role in the progression of tumors and chronic conditions such as diabetes and chronic kidney disease. Senescent cells are an important model for the study of aging-related diseases, and there is currently no efficient method for sorting out senescent cells. Decoy receptor 2 (DcR2) is a transmembrane receptor of the tumor necrosis factor superfamily, which is specifically expressed in senescent cells. In this study, we used magnetic activated cell sorting (MACS) isolation of a highly-pure populations DcR2-positive renal tubular epithelial cells (RTECs) based on three senescent cell models including the fifth passage cells, advanced glycation end-products (AGEs)- and H₂O₂-induced cells. The percentages of DcR2 positive RTECs in G1 and S phases increased by 20% and 4%, respectively, as compared to that in the pre-sorted cells. The positivity rates of SA-β-gal, p16, and senescence-associated heterochromatin foci (SAHF) in DcR2-positive RTECs were about 40%, 30%, and 44% higher than that prior to cell sorting. The levels of IL-6 and TGF-β1 in the supernatant were increased by 1.7 and 1.5 folds, respectively, as compared to that observed prior to sorting. No significant cell death was observed after 5days of continuous culture. Ki-67 positive expression rate in DcR2 negative RTECs was significantly higher than that in DcR2 positive RTECs after MACS. We demonstrated the use of DcR2 to classify live, senescent RTECs with a high specificity and stability. Our findings lay the foundation for further study of senescent RTECs in the progression of chronic kidney disease.