Y SHI1, Y ZHAO2, CL HUANG1, X CHEN1, C POLLOCK1
1Kolling Institute, University of Sydney, Royal North Shore Hospital, Sydney, New South Wales; 2The Second Hospital, Dalian Medical University, China
Aim: To define the role of RIPK3 blocking in alleviating renal fibrogenesis.
Background: Current therapies for renal fibrosis are largely ineffective. Therefore, identification of novel therapeutic targets is essential. RIPK3 is identified as a crucial regulator of necrosis, apoptosis and inflammation, which have been well recognized to be involved in renal fibrogenesis. To date, the role of RIPK3 in renal fibrosis has not been reported.
Methods: C57BL/6 wild-type and RIPK3 gene knock out (RIPK3-/-) mice and two interventional strategies were used in the study. 1. Folic acid was administrated i.p. to induce kidney injury in both WT and RIPK3-/- mice for 28 days; 2. C57BL/6 WT mice injected with folic acid were treated with Dabrafenib (RIPK3 inhibitor) or vehicle respectively for 28 days. Kidneys were harvested from above experiments and kidney function was assessed by measuring 24 hour of urinary albumin excretion and urinary albumin creatinine ratio (UACR) by ELISAs. Kidney histological change and collagen deposition was assessed by PAS, Masson’s trichrome and picrosirius red staining. MCP-1, TGF-β and a-SMA RNA expression level were detected by quantitative RTPCR analysis.
Results: RIPK3 blockade reversed folic acid increased 24 hour urinary albumin excretion and decreased UACR compared to WT or vehicle control groups treated with folic acid. Histological analysis has shown that folic acid
resulted in increased collagen accumulation and ECM deposition, whereas, RIPK3 inhibition attenuated ECM deposition and renal fibrosis. In addition, quantitative RT-PCR demonstrated Dabrafenib treated mice and RIPK3-/-
mice inhibited RNA expression of MCP-1 TGF-β and a-SMA. Conclusions: These results suggest that RIPK3 blockade may be a potential novel target in renal fibrosis.