Resveratrol protects primary hepatocytes against senescence induced by endogenous toxic metabolites.

Liver dysfunction rates increase markedly with ageing causing the plasma concentrations of toxic endogenous metabolites to rise. We demonstrated that brief exposure of HepG2 cells in vitro to a liver-derived toxic metabolite cocktail triggers a distinct state of cellular senescence termed senescence induced by liver toxins (SILT). SILT combines classical features of senescence (loss of proliferative capacity, proinflammatory changes, senescence associated β- galactosidase reactivity and cyclin dependent kinase inhibitor upregulation) with a broader loss of essential hepatocyte functions. Immortalised cell lines are valuable models for primary hepatic function but also show important physiological differences. We have extended our analysis to primary hepatocytes and have found that both human and porcine liver cells undergo SILT in vitro when exposed to the concentrations of endogenous toxins typical of liver disease. As in HepG2 cells, SILT in primary hepatocytes was accompanied by loss of albumin production (as measured by ELISA) and urea synthesis (measured biochemically) but was reversible by 5µM resveratrol in a species- and function-dependent manner. Deeper transcriptomic profiling of SILT revealed the activation of stress and inflammatory pathways combined and repression of hepatocyte metabolic programmes. Gene Set Enrichment Analysis demonstrates that the SILT is present in vivo in multiple reference transcriptomic datasets derived from diseased, but not healthy liver. This is consistent with the presence of a population of SILT hepatocytes among the senescent cells found in the ageing organ in vivo. Thus, SILT may contribute to the ultimate failure of liver function which may potentially be delayed by resveratrol treatment.