Patterns of bacterial viability governing noncanonical inflammasome activation

Noncanonical inflammasomes are instrumental in defense against Gram-negative bacteria, activated primarily by bacterial lipopolysaccharide. This review examines commonalities and distinctions in noncanonical inflammasome activation either by virulence factor activity indicating cellular invasion or by detection of bacterial mRNA signaling the undesired presence of live bacteria in sterile tissue. These inflammasome triggers, alongside other examples discussed, reflect properties exclusive to live bacteria. The emerging picture underscores noncanonical inflammasome activation hinging on detection of indicators of bacterial viability such as the presence of certain molecules or activity of specific processes. The complex interpretation of combinatorial signals is essential for inflammasome activation according to the specific facet of infection confronting the host. Decoding these signals and their convergence on inflammasome activation will inform interventions and therapies for infectious diseases.