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J Neurochem. 2014 May;129(4):704-11. doi: 10.1111/jnc.12669. Epub 2014 Feb 19.

Critical role for the AIM2 inflammasome during acute CNS bacterial infection.

Author information

1
Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA.

Abstract

Interleukin-1β (IL-1β) is essential for eliciting protective immunity during the acute phase of Staphylococcus aureus (S. aureus) infection in the central nervous system (CNS). We previously demonstrated that microglial IL-1β production in response to live S. aureus is mediated through the Nod-like receptor protein 3 (NLRP3) inflammasome, including the adapter protein ASC (apoptosis-associated speck-like protein containing a caspase-1 recruitment domain), and pro-caspase 1. Here, we utilized NLRP3, ASC, and caspase 1/11 knockout (KO) mice to demonstrate the functional significance of inflammasome activity during CNS S. aureus infection. ASC and caspase 1/11 KO animals were exquisitely sensitive, with approximately 50% of mice succumbing to infection within 24 h. Unexpectedly, the survival of NLRP3 KO mice was similar to wild-type animals, suggesting the involvement of an alternative upstream sensor, which was later identified as absent in melanoma 2 (AIM2) based on the similar disease patterns between AIM2 and ASC KO mice. Besides IL-1β, other key inflammatory mediators, including IL-6, CXCL1, CXCL10, and CCL2 were significantly reduced in the CNS of AIM2 and ASC KO mice, implicating autocrine/paracrine actions of IL-1β, as these mediators do not require inflammasome processing for secretion. These studies demonstrate a novel role for the AIM2 inflammasome as a critical molecular platform for regulating IL-1β release and survival during acute CNS S. aureus infection.

KEYWORDS:

AIM2; ASC; Staphylococcus aureus; caspase 1; inflammasome; interleukin-1

PMID:
24484406
PMCID:
PMC3999210
DOI:
10.1111/jnc.12669
[Indexed for MEDLINE]
Free PMC Article

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