RIPK3 activation promotes peritoneal dialysis-related peritoneal fibrosis via NLRP3/Caspase-1/IL-1β pathway

Peritoneal fibrosis is one of the leading causes for withdraw of peritoneal dialysis (PD) but there is no available effective therapy strategy. As an essential role in regulating TNF-induced necroptosis, receptor interacting protein kinase-3 (RIPK3) participated in the progression of multiple organ fibrosis. Here, we investigated the role and the possible mechanism of RIPK3 in PD-associated peritoneal fibrosis in PD patients, a mouse peritoneal dialysis model and in vitro peritoneal mesothelial cells. We found that phosphorylated-RIPK3 (p-RIPK3) were markedly elevated in PD fluids and peritoneal tissue from PD patients, a mouse PD model and in peritoneal mesothelial cells induced by TGFβ and high glucose PD fluids. And activated RIPK3 recruits its substrate protein, MLKL, and promotes its phosphorylation. RIPK3 kinase inhibition using GSK'872 compound could attenuate high glucose PD fluid-induced peritoneal fibrosis in a mouse PD model. In vitro peritoneal mesothelial cells, RIPK3 kinase inhibition or siRNA transfection target on RIPK3 attenuate TGFβ or high glucose PD fluid-induced fibrotic progress. Meanwhile, GSK'872 intervention could inhibit the NLRP3/Caspase-1/IL-1β pathway in PD mouse model and in vitro peritoneal mesothelial cells, inhibiting RIPK3 kinase activity or siRNA silencing RIPK3 expression could block NLRP3/Caspase-1/IL-1β pathway. Moreover, Co-immunoprecipitation (Co-IP) experiment and immunofluorescence indicated that p-RIPK3 could combinate with NLRP3 and TGFβ intervention could promote this interaction, while RIPK3 kinase inhibitor could avianize their combination. These findings implicate that RIPK3 activation may be a crucial mediator in PD associated peritoneal fibrosis and targeting RIPK3 activation may be a novel therapeutic strategy to attenuate PD-related peritoneal fibrosis.