P0516DCR2 PROMOTES RENAL FIBROSIS BY ACCELERATING TUBULAR CELL SENESCENCE AFTER ISCHEMIA REPERFUSION INJURY

Abstract

Abstract Background and Aims Cell senescence of renal tubular epithelial cells (RTECs), which is involved in renal fibrosis, is a key event in the progression of acute kidney injury (AKI). However, the underlying mechanism remains unclear. This study aims to investigate the role and mechanism of decoy receptor 2 (DcR2) in renal fibrosis and cell senescence of RTECs. Method KSP-creDcR2f/f mouse (Tubular DcR2 KO) and Ischemia-Reperfusion (I/R) Injury models were constructed. The models were divided into moderated (ischemia 20min) and severe (ischemia 35min) injury. The expression of renal DcR2, senescent markers (P16, P21, SA-β-gal) and senescent phenotype (IL-6, TGF-β1) were detected. Furthermore, wild type (WT) mice and KSP-creDcR2f/f mice were used to compare the degree of renal tissue and functional damage and the senescence of renal tubular cells after I/R injury. In vitro, knockdown and overexpression experiments were performed by transfected DcR2 siRNA or overexpressed adenovirus in hypoxia-reoxygenation stimulated mouse primary RTEC. The cell senescence and phenotype markers were further detected. Results The levels of Scr, BUN and urinary DcR2 and renal injury scores were significantly increased in I/R group at the early stage (1d) of renal injury compared with sham group. Renal fibrosis was observed in the later stage (21-42d) in severe injury. DcR2 was mainly expressed in renal tubules, and the percentage of tubular DcR2 was increased after I/R injury. DcR2 was co-expressed with P16 and SA-β-gal, and urinary DcR2 levels were related to senescent makers, suggesting that DcR2 was associated with cell senescence. The renal function and renal injury scores were lower in KSP-creDcR2f/f mice than that of WT after renal reperfusion. And the area of renal fibrosis was significantly decreased in KSP-creDcR2f/f mice compared with WT, indicating DcR2 inhibited renal fibrosis. Furthermore, the expression of senescent phenotype were suppressed in tubular DcR2 KO mice after I/R injury, suggesting that DcR2 could promote the senescence of renal tubule cells. Conclusion DcR2 promotes renal fibrosis by accelerating tubular cell senescence after ischemia-reperfusion Injury, suggesting that DcR2 may be a potential intervention target during the progression of AKI.