Bacterial secretion systems and regulation of inflammasome activation.
Innate immunity is critical for host defenses against pathogens, but many bacteria display complex ways of interacting with innate immune signaling, as they may both activate and evade certain pathways. Gram-negative bacteria can exhibit specialized nanomachine secretion systems for delivery of effector proteins into mammalian cells. Bacterial types III, IV, and VI secretion systems (T3SS, T4SS, and T6SS) are known for their impact on caspase-1-activating inflammasomes, necessary for producing bioactive inflammatory cytokines IL-1β and IL-18, key participants of anti-bacterial responses. Here, we discuss how these secretion systems can mediate triggering and inhibition of inflammasome signaling. We propose that a fine balance between secretion system-mediated activation and inhibition can determine net activation of inflammasome activity and control inflammation, clearance, or spread of the infection.
Program in Innate Immunity, Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA; and.
Dmitry
D
Ratner
Program in Innate Immunity, Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA; and.|Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norges Teknisk-Naturvitenskapelige Universitet, Trondheim, Norway.
M Pontus A
MP
Orning
Program in Innate Immunity, Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA; and egil.lien@umassmed.edu.|Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norges Teknisk-Naturvitenskapelige Universitet, Trondheim, Norway.
Egil
E
Lien
D000818:Animals; D001419:Bacteria / Q000276:immunology; D058947:Bacterial Secretion Systems; D004194:Disease; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology; D058847:Inflammasomes / Q000378:metabolism*; D008954:Models, Biological
D058947:Bacterial Secretion Systems; D058847:Inflammasomes
Interleukin-18; Interleukin-1beta; caspase-1; pyroptosis