Caspase-11 attenuates gastrointestinal inflammation and experimental colitis pathogenesis

Area of Science:

• Immunology
• Gastroenterology
• Molecular Biology

Background:

• Nucleotide-binding domain and leucine-rich repeat containing protein (NLRC) inflammasomes are crucial for gut immune homeostasis.
• A noncanonical inflammasome involving caspase-11 modulates functions previously attributed solely to caspase-1 and the canonical inflammasome.

Purpose of the Study:

• To investigate the role of the caspase-11 noncanonical inflammasome in experimental inflammatory bowel disease.
• To elucidate the protective mechanisms of caspase-11 during acute dextran sulfate sodium (DSS)-induced colitis.

Main Methods:

• Experimental colitis was induced in wild-type and Casp11(-/-) mice using DSS.
• Morbidity, colon inflammation, and cytokine levels (IL-1β, IL-18) were assessed.
• Mechanistic studies included cytokine reconstitution and bone marrow chimera experiments.

Main Results:

• Caspase-11 deficiency (Casp11(-/-)) significantly increased morbidity and colon inflammation following DSS exposure.
• IL-1β and IL-18 levels were significantly reduced in Casp11(-/-) mice, and their absence contributed to hypersensitivity.
• Caspase-11 function in both hematopoietic and nonhematopoietic cells was essential for disease attenuation.

Conclusions:

• Caspase-11 is a critical host protective factor against acute DSS-induced colonic injury and inflammation.
• Caspase-11 does not appear to influence chronic relapsing-remitting colitis or colitis-associated tumorigenesis.
• These findings identify a distinct role for the noncanonical caspase-11 inflammasome in acute gut inflammation distinct from canonical inflammasome pathways.