Inflammasomes in chronic liver disease: Hepatic injury, fibrosis progression and systemic inflammation

Abstract

Chronic liver disease leads to hepatocellular injury that triggers a pro-inflammatory state in several parenchymal and non-parenchymal hepatic cell types, ultimately resulting in liver fibrosis, cirrhosis, portal hypertension and liver failure. Thus, an improved understanding of inflammasomes – as key molecular drivers of liver injury – may result in the development of novel diagnostic or prognostic biomarkers and effective therapeutics. In liver disease, innate immune cells respond to hepatic insults by activating cell-intrinsic inflammasomes via toll-like receptors and NF-κB, and by releasing pro-inflammatory cytokines (such as IL-1β, IL-18, TNF-α and IL-6). Subsequently, cells of the adaptive immune system are recruited to fuel hepatic inflammation and hepatic parenchymal cells may undergo gasdermin D-mediated programmed cell death, termed pyroptosis. With liver disease progression, there is a shift towards a type 2 inflammatory response, which promotes tissue repair but also fibrogenesis. Inflammasome activation may also occur at extrahepatic sites, such as the white adipose tissue in MASH (metabolic dysfunction-associated steatohepatitis). In end-stage liver disease, flares of inflammation (e.g., in severe alcohol-related hepatitis) that spark on a dysfunctional immune system, contribute to inflammasome-mediated liver injury and potentially result in organ dysfunction/failure, as seen in ACLF (acute-on-chronic liver failure). This review provides an overview of current concepts regarding inflammasome activation in liver disease progression, with a focus on related biomarkers and therapeutic approaches that are being developed for patients with liver disease.