Inhibition of Rb phosphorylation leads to H2S-mediated inhibition of NF-kB in acute pancreatitis and associated lung injury in mice

Abstract

BackgroundAcute pancreatitis (AP), an inflammatory condition of pancreas, destructs the exocrine cells by releasing various pro-inflammatory cytokines that activates the stellate cells. However, the underlying molecular mechanism remains unclear. The present study investigated the role of retinoblastoma (Rb), hydrogen sulphide and nuclear factor-κB (NF-κB) in the regulation of exocrine cell proliferation under inflammatory condition. MethodsThe randomly grouped male swiss mice were administered with 6 consecutive hourly i.p injections of caerulein to induce AP. Palbociclib (PD) (25 mg/kg body weight), a CDK4/6 inhibitor, was administered 1 h after the first cerulein injection intraperitoneally to block the RB pathway by inhibiting the activity of the CDK4/6 complexes and DL propargylglycine (PAG) which blocks the endogenous H2S production. ResultsPharmacological inhibition of CDK4/6 and H2S significantly improved pancreas and lung histopathological changes, decreased serum amylase level, both lung and pancreas myeloperoxidase (MPO) activity, TNFα expression and elevated IL10 expression. Furthermore, inhibition of RB pathway reduced cerulein-induced H2S level by reducing the expression of cystathionine gamma lyase (CSE) and NF-κB activation in pancreas and lungs. Also, blocking the RB signalling reduced the α-SMA expression in pancreas preventing the risk for pancreatic fibrosis. Whereas administration of H2S inhibitor PAG resulted in a decrease in CDK4/6-Rb expression in cerulein-induced AP. ConclusionThese results reveal a novel link between H2S/RB/NF-κB pathways, in AP and provide insight into possible mechanism that can be targeted in prevention of inflammation to cancer development.