Hexafluoropropylene oxide trimer acid causes fibrosis in mice liver via mitochondrial ROS/cGAS-STING/NLRP3-mediated pyroptosis

NLRP3 (NACHT, LRR and PYD domains-containing protein 3) is an intracellular sensor that detects a broad range of microbial motifs, endogenous danger signals and environmental irritants, resulting in the formation and activation of the NLRP3 inflammasome. Assembly of the NLRP3 inflammasome leads to caspase-1-dependent release of the proinflammatory cytokines, IL-1β and IL-18, as well as to gasdermin D-mediated pyroptotic cell death. Recent studies have revealed new regulators of the NLRP3 inflammasome, including new interacting or regulatory proteins, metabolic pathways and a regulatory mitochondrial hub. In this Review, we present the molecular, cell biological and biochemical basis of NLRP3 activation and regulation, and describe how this mechanistic understanding is leading to potential therapeutics that target the NLRP3 inflammasome.

Eukaryotic cells can initiate several distinct programmes of self-destruction, and the nature of the cell death process (non-inflammatory or proinflammatory) instructs responses of neighbouring cells, which in turn dictates important systemic physiological outcomes. Pyroptosis, or caspase 1-dependent cell death, is inherently inflammatory, is triggered by various pathological stimuli, such as stroke, heart attack or cancer, and is crucial for controlling microbial infections. Pathogens have evolved mechanisms to inhibit pyroptosis, enhancing their ability to persist and cause disease. Ultimately, there is a competition between host and pathogen to regulate pyroptosis, and the outcome dictates life or death of the host.

The cGAS–STING signalling pathway has emerged as a key mediator of inflammation in the settings of infection, cellular stress and tissue damage. Underlying this broad involvement of the cGAS–STING pathway is its capacity to sense and regulate the cellular response towards microbial and host-derived DNAs, which serve as ubiquitous danger-associated molecules. Insights into the structural and molecular biology of the cGAS–STING pathway have enabled the development of selective small-molecule inhibitors with the potential to target the cGAS–STING axis in a number of inflammatory diseases in humans. Here, we outline the principal elements of the cGAS–STING signalling cascade and discuss the general mechanisms underlying the association of cGAS–STING activity with various autoinflammatory, autoimmune and degenerative diseases. Finally, we outline the chemical nature of recently developed cGAS and STING antagonists and summarize their potential clinical applications.