Inflammasome Activation and Innate Immunity in Host Defense

The innate immune system employs inflammasomes—intracellular multiprotein platforms—to detect microbial motifs and danger signals, triggering rapid inflammatory responses. Upon sensing perturbations such as ion flux changes, reactive oxygen species or cytosolic DNA, sensor proteins (including NLRP3, NLRP6, NLRC4 and AIM2) recruit the adaptor ASC and pro-caspase-1, culminating in caspase-1 activation. Caspase-1 then cleaves pro-IL-1β and pro-IL-18 into their mature forms and processes gasdermin D, whose N-terminal fragments form membrane pores that drive pyroptosis. This coordinated programme restricts pathogen replication, recruits immune cells and shapes adaptive immunity. Crosstalk with autophagy and ubiquitin-mediated pathways ensures homeostatic control, while dysregulation underlies autoinflammatory diseases, neurodegeneration and malignancy. Recent advances in structural biology and mechanistic studies have revealed stepwise assembly of inflammasome complexes, non-canonical signalling roles of certain NLRs and links to metabolic pathways. These insights highlight the therapeutic potential of selectively modulating inflammasome activation to bolster host defense while limiting collateral tissue damage.

Research from Nature Portfolio

Recent studies have elucidated the molecular versatility of NLRP6. Comprehensive analysis in 2022 revealed that NLRP6 functions both as an inflammasome sensor and as a regulator of signalling pathways independent of caspase-1, exerting context-dependent pro- and anti-inflammatory effects in the gut, liver and nervous system. Structural work from 2020 demonstrated that binding of lipopolysaccharide induces NLRP6 conformational change and dimerisation, followed by ATP-driven assembly of a linear scaffold that recruits ASC into higher-order filaments, outlining a stepwise activation mechanism. More recent research has uncovered a non-canonical role for NLRP6 in selective autophagy: it targets the PI3K regulatory subunit p85α for ubiquitin-dependent degradation, thereby modulating PI3K/AKT signalling and revealing potential intersections between inflammasome activity and tumourigenic processes.

Inflammasome Activation and Innate Immunity in Host Defense publication trend

The graph below shows the total number of articles in inflammasome activation and innate immunity in host defense across all publications each year (not limited to Nature Index journals).

Technical terms

Inflammasome: A cytosolic protein complex that activates inflammatory caspases in response to pathogens or danger signals.

Pyroptosis: A lytic form of programmed cell death driven by gasdermin D pore formation.

Autophagy: A conserved process that degrades cellular components via lysosomal pathways.

Deubiquitination: Removal of ubiquitin tags from proteins, often altering their stability or function.

Gasdermin D: A pore-forming substrate of inflammatory caspases that mediates membrane rupture.

Caspase-1: An inflammatory protease that processes pro-interleukins and gasdermin D.

ASC: An adaptor protein that links inflammasome sensors to pro-caspase-1 activation.

IL-1β: A key pro-inflammatory cytokine produced upon inflammasome activation.

References

1. NLRP6 potentiates PI3K/AKT signalling by promoting autophagic degradation of p85α to drive tumorigenesis. Nature Communications (2023).
2. Inflammasome activation by Gram-positive bacteria: Mechanisms of activation and regulation. Frontiers in Immunology (2023).
3. BRCC3 mediates inflammation and pyroptosis in cerebral ischemia/reperfusion injury by activating the NLRP6 inflammasome. CNS Neuroscience & Therapeutics (2024).
4. NLRP6 self-assembles into a linear molecular platform following LPS binding and ATP stimulation. Scientific Reports (2020).
5. Estrogen receptor β activation inhibits colitis by promoting NLRP6-mediated autophagy. Cell Reports (2022).
6. Physiological and pathophysiological functions of NLRP6: pro- and anti-inflammatory roles. Communications Biology (2022).