The interactions of chemokines with their G protein-coupled receptors promote the migration of leukocytes during normal immune function and as a key aspect of the inflammatory response to tissue injury or infection. This review summarizes the major cellular and biochemical mechanisms by which the interactions of chemokines with chemokine receptors are regulated, including: selective and competitive binding interactions; genetic polymorphisms; mRNA splice variation; variation of expression, degradation and localization; down-regulation by atypical (decoy) receptors; interactions with cell-surface glycosaminoglycans; post-translational modifications; oligomerization; alternative signaling responses; and binding to natural or pharmacological inhibitors.

The inflammasome is a macromolecular protein complex that mediates proteolytic cleavage of pro-IL-1β and -IL-18 and induces cell death in the form of pyroptosis. Certain nucleotide-binding oligomerization domain-like receptors (NLRs), absent in melanoma 2 (AIM2)-like receptors (ALRs), or tripartite motif (TRIM) family receptors trigger the assembly of an inflammasome in response to pathogen-associated molecular patterns (PAMPs) or danger-associated molecular patterns (DAMPs). Recent studies have revealed a multitude of host components and signals that are essential for controlling canonical and noncanonical inflammasome activation and pyroptosis. These include pore-forming gasdermin proteins, the never in mitosis A-related kinase 7 (NEK7), IFN-inducible proteins (IFIs), reactive oxygen species (ROS), autophagy, potassium efflux, mitochondrial perturbations, and microbial metabolites. Here, we provide a comprehensive overview of the molecular and signaling mechanisms that provide stringent regulation over the activation and effector functions of the inflammasome.

Infection is a dynamic biological process underpinned by a complex interplay between the pathogen and the host. Microbes from all domains of life, including bacteria, viruses, fungi, and protozoan parasites, have the capacity to cause infection. Infection is sensed by the host, which often leads to activation of the inflammasome, a cytosolic macromolecular signaling platform that mediates the release of the proinflammatory cytokines interleukin-1β (IL-1β) and IL-18 and cleavage of the pore-forming protein gasdermin D, leading to pyroptosis. Host-mediated sensing of the infection occurs when pathogens inject or carry pathogen-associated molecular patterns (PAMPs) into the cytoplasm or induce damage that causes cytosolic liberation of danger-associated molecular patterns (DAMPs) in the host cell. Recognition of PAMPs and DAMPs by inflammasome sensors, including NLRP1, NLRP3, NLRC4, NAIP, AIM2, and Pyrin, initiates a cascade of events that culminate in inflammation and cell death. However, pathogens can deploy virulence factors capable of minimizing or evading host detection. This review presents a comprehensive overview of the mechanisms of microbe-induced activation of the inflammasome and the functional consequences of inflammasome activation in infectious diseases. We also explore the microbial strategies used in the evasion of inflammasome sensing at the host-microbe interaction interface.

Host recognition of microbial components is essential in mediating an effective immune response. Cytosolic bacteria must secure entry into the host cytoplasm to facilitate replication, and in doing so, liberating microbial ligands which activate cytosolic innate immune sensors and the inflammasome. Here, we identified a multi-component enterotoxin hemolysin BL (HBL) which