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High-mobility group box-1 (HMGB1) significantly increases and undergoes post-translational modifications (PTMs) in response to liver injury. Since oxidative stress plays a major role in liver fibrosis and induces PTMs in proteins, we hypothesized that redox-sensitive HMGB1 isoforms contribute to liver fibrosis progression and resolution. We used ESI-LC-MS (electrospray ionization-liquid chromatography-mass spectrometry) to study PTMs of HMGB1 during fibrosis progression and resolution. Conditional knockout mice were used for functional analyses. We identified that disulfide ([O]) and sulfonated ([SO 3 ]) HMGB1 increase during carbon tetrachloride-induced liver fibrosis progression, however, while [O] HMGB1 declines, [SO 3 ] HMGB1 drops but remains, during fibrosis resolution. Conditional knockout of Hmgb1 revealed that production of [O] and [SO 3 ] HMGB1 occurs mostly in hepatocytes. Co-injection of [O] HMGB1 worsens carbon tetrachloride-induced liver fibrosis more than co-injection of [H] HMGB1. Conversely, ablation of [O] Hmgb1 in hepatocytes reduces liver fibrosis. Moreover, ablation of the receptor for advanced-glycation end-products (Rage) reveals that the profibrogenic effect of [O] HMGB1 is mediated by RAGE signaling in hepatic stellate cells (HSCs). Notably, injection of [SO 3 ] HMGB1 accelerates fibrosis resolution due to RAGE-dependent stimulation of HSC apoptosis. Importantly, gene signatures activated by redox-sensitive HMGB1 isoforms in mice, classify patients with fibrosis according to fibrosis and inflammation scores. Dynamic changes in hepatocyte-derived [O] and [SO 3 ] HMGB1 signal through RAGE-dependent mechanisms on HSCs to drive their profibrogenic phenotype and fate, contributing to progression and resolution of liver fibrosis. Since oxidative stress plays a major role in liver fibrosis and induces post-translational modifications of proteins, we hypothesized that redox-sensitive HMGB1 isoforms contribute to liver fibrosis progression and resolution. This study is significant because a rise in [H] HMGB1 could flag 'patient at risk', the presence of [O] HMGB1 could suggest 'disease in progress or active scarring', while the appearance of [SO 3 ] HMGB1 could point at 'resolution under way'. The latter could be used as a readout for response to pharmacological intervention with anti-fibrotic agents. [Display omitted] • We identified post-translational modifications of HMGB1 during liver fibrosis progression ([O] and [SO 3 ] HMGB1) and resolution ([SO 3 ] HMGB1). • The pro-fibrogenic effect of [O] HMGB1 is mediated by RAGE signaling in hepatic stellate cells. • [SO 3 ] HMGB1 accelerates fibrosis resolution via RAGE-dependent stimulation of hepatic stellate cell apoptosis. • Gene signatures, activated by redox-sensitive HMGB1 isoforms in mice, classify patients according to fibrosis and inflammation scores. [ABSTRACT FROM AUTHOR]

Damage-associated molecular patterns are signalling molecules involved in inflammatory responses and restoration of homeostasis. Chronic release of these molecules can also promote inflammation in the context of liver disease. Herein, we provide a comprehensive summary of the role of damage-associated molecular patterns as danger signals in liver injury. We consider the role of reactive oxygen species and reactive nitrogen species as inducers of damage-associated molecular patterns, as well as how specific damage-associated molecular patterns participate in the pathogenesis of chronic liver diseases such as alcohol-related liver disease, non-alcoholic steatohepatitis, liver fibrosis and liver cancer. In addition, we discuss the role of damage-associated molecular patterns in ischaemia reperfusion injury and liver transplantation and highlight current studies in which blockade of specific damage-associated molecular patterns has proven beneficial in humans and mice. [ABSTRACT FROM AUTHOR]