P0516
DCR2 PROMOTES RENAL FIBROSIS BY ACCELERATING TUBULAR CELL SENESCENCE AFTER ISCHEMIA REPERFUSION INJURY

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.

^KSP-creDcR2^f/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-creDcR2^f/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.

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-creDcR2^f/f mice than that of WT after renal reperfusion. And the area of renal fibrosis was significantly decreased in ^KSP-creDcR2^f/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.

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.

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