Inhibition of the inflammasome complex reduces the inflammatory response after thromboembolic stroke in mice.
Inflammation is a major contributor to the pathogenesis of cerebral ischemia and stroke. In the peripheral immune response, caspase-1 activation involves the formation of a macromolecular complex termed the inflammasome. We determined whether nucleotide-binding, leucine-rich repeat, pyrin domain containing 1 (NLRP1), molecular platform consisting of capase-1, apoptosis-associated speck-like protein containing a caspase-activating recruitment domain (ASC), and NLRP1, is expressed in the normal and postischemic brain. Mice underwent thromboembolic stroke to investigate the formation of the inflammasome and subsequent activation of downstream inflammatory responses. Western blot analysis showed expression and activation of interleukin (IL) IL-1beta and IL-18 at 24 h after stroke. Size-exclusion chromatography and coimmunoprecipitation analysis showed protein association between NLRP1, ASC, caspase-1, and the X-linked inhibitor of apoptosis protein (XIAP). After ischemia, immunohistochemical analysis revealed inflammasome proteins in neurons, astrocytes, and microglia/macrophages. The potential of the inflammasome as an antiinflammatory target was showed by interference of inflammasome activation resulting in reduced cytokine levels in mice treated after ischemia with a neutralizing antibody against NLRP1. These findings show that the inflammasome complex forms after focal brain ischemia and may be a novel therapeutic target for reducing the detrimental consequences of postischemic inflammation.
Abulafia
Denise P
DP
Department of Cell Biology and Anatomy, University of Miami Miller School of Medicine, Miami, Florida 33136, USA.
de Rivero Vaccari
Juan Pablo
JP
Lozano
J Diego
JD
Lotocki
George
G
Keane
Robert W
RW
Dietrich
W Dalton
WD
D048868:Adaptor Proteins, Signal Transducing / Q000037:antagonists & inhibitors* / Q000276:immunology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology / Q000627:therapeutic use; D051017:Apoptosis Regulatory Proteins / Q000037:antagonists & inhibitors* / Q000276:immunology; D002341:Carotid Artery Thrombosis / Q000150:complications* / Q000276:immunology; D020170:Caspase 1 / Q000276:immunology; D061945:Caspase Inhibitors; D004660:Encephalitis / Q000276:immunology / Q000517:prevention & control*; D047468:Immunoprecipitation; D020382:Interleukin-18 / Q000037:antagonists & inhibitors / Q000276:immunology; D053583:Interleukin-1beta / Q000037:antagonists & inhibitors / Q000276:immunology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D020521:Stroke / Q000209:etiology* / Q000276:immunology; D013923:Thromboembolism / Q000150:complications* / Q000276:immunology
D048868:Adaptor Proteins, Signal Transducing; D000911:Antibodies, Monoclonal; D051017:Apoptosis Regulatory Proteins; D061945:Caspase Inhibitors; D020382:Interleukin-18; D053583:Interleukin-1beta; C529636:NALP1 protein, mouse; D020170:Caspase 1