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Am J Respir Crit Care Med. 2017 Sep 15;196(6):713-726. doi: 10.1164/rccm.201604-0892OC.

NLRP3 Inflammasome Deficiency Protects against Microbial Sepsis via Increased Lipoxin B4 Synthesis.

Author information

1
1 Division of Pulmonary and Critical Care Medicine and.
2
2 Department of Critical Care Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
3
3 Division of Pulmonary and Critical Care Medicine, Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medical College, New York, New York.
4
4 Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Harvard Institutes of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
5
5 First Department of Critical Care Medicine and Pulmonary Services, Evangelismos Hospital, University of Athens Medical School, Athens, Greece.
6
6 Division of Pulmonary and Critical Care Medicine, Penn State College of Medicine, Hershey, Pennsylvania; and.
7
7 New York Presbyterian Hospital, Weill Cornell Medical Center, New York, New York.

Abstract

RATIONALE:

Sepsis, a life-threatening organ dysfunction caused by a dysregulated host response to infection, is a major public health concern with high mortality and morbidity. Although inflammatory responses triggered by infection are crucial for host defense against invading microbes, the excessive inflammation often causes tissue damage leading to organ dysfunction. Resolution of inflammation, an active immune process mediated by endogenous lipid mediators (LMs), is important to maintain host homeostasis.

OBJECTIVES:

We sought to determine the role of the nucleotide-binding domain, leucine-rich repeat-containing receptor, pyrin domain-containing-3 (NLRP3) inflammasome in polymicrobial sepsis and regulation of LM biosynthesis.

METHODS:

We performed cecal ligation and puncture (CLP) using mice lacking NLRP3 inflammasome-associated molecules to assess mortality. Inflammation was evaluated by using biologic fluids including plasma, bronchoalveolar, and peritoneal lavage fluid. Local acting LMs in peritoneal lavage fluid from polymicrobacterial septic mice were assessed by mass spectrometry-based metabololipidomics.

MEASUREMENTS AND MAIN RESULTS:

Genetic deficiency of NLRP3 inhibited inflammatory responses and enhanced survival of CLP-induced septic mice. NLRP3 deficiency reduced proinflammatory LMs and increased proresolving LM, lipoxin B4 (LXB4) in septic mice, and in macrophages stimulated with LPS and ATP. Activation of the NLRP3 inflammasome induced caspase-7 cleavage and pyroptosis. Caspase-7 deficiency similarly reduced inflammation and mortality in CLP-induced sepsis, and increased LXB4 production in vivo and in vitro. Exogenous application of LXB4 reduced inflammation, pyroptosis, and mortality of mice after CLP.

CONCLUSIONS:

Genetic deficiency of NLRP3 promoted resolution of inflammation in polymicrobial sepsis by relieving caspase-7-dependent repression of LXB4 biosynthesis, and increased survival potentially via LXB4 production and inhibition of proinflammatory cytokines.

KEYWORDS:

NLRP3 inflammasome; lipid mediators; sepsis

PMID:
28245134
PMCID:
PMC5620673
DOI:
10.1164/rccm.201604-0892OC
[Indexed for MEDLINE]
Free PMC Article

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