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Autophagy. 2016 Aug 2;12(8):1272-91. doi: 10.1080/15548627.2016.1183081. Epub 2016 Jun 23.

SESN2/sestrin2 suppresses sepsis by inducing mitophagy and inhibiting NLRP3 activation in macrophages.

Kim MJ1,2, Bae SH3, Ryu JC1,2, Kwon Y1,2, Oh JH1,2, Kwon J4, Moon JS5,6, Kim K7, Miyawaki A8, Lee MG2,3,9, Shin J4, Kim YS10, Kim CH11,12, Ryter SW5,6, Choi AM5,6, Rhee SG3, Ryu JH2,3, Yoon JH1,2,11,12.

Author information

1
a Research Center for Natural Human Defense System , Yonsei University College of Medicine , Seoul , Korea.
2
b Brain Korea 21 PLUS Project for Medical Science , Yonsei University College of Medicine , Seoul , Korea.
3
c Severance Biomedical Science Institute, Yonsei University College of Medicine , Seoul , Korea.
4
d Sungkyunkwan University School of Medicine and Samsung Biomedical Research Institute , Suwon , Korea.
5
e Joan and Sanford I. Weill Department of Medicine , Weill Cornell Medical College and New York-Presbyterian Hospital , New York , NY USA.
6
f Division of Pulmonary and Critical Care Medicine , Weill Cornell Medical College , New York , NY USA.
7
g Department of Otorhinolaryngology-Head and Neck Surgery , Hallym University College of Medicine, Kangdong Sacred Heart Hospital , Seoul , Korea.
8
h Laboratory for Cell Function Dynamics , Brain Science Institute, RIKEN , Wako, Saitama Japan.
9
i Department of Pharmacology , Yonsei University College of Medicine , Seoul , Korea.
10
j Department of Internal Medicine , Yonsei University College of Medicine , Seoul , Korea.
11
k Department of Otorhinolaryngology.
12
l The Airway Mucus Institute, Yonsei University College of Medicine , Seoul , Korea.

Abstract

Proper regulation of mitophagy for mitochondrial homeostasis is important in various inflammatory diseases. However, the precise mechanisms by which mitophagy is activated to regulate inflammatory responses remain largely unknown. The NLRP3 (NLR family, pyrin domain containing 3) inflammasome serves as a platform that triggers the activation of CASP1 (caspase 1) and secretion of proinflammatory cytokines. Here, we demonstrate that SESN2 (sestrin 2), known as stress-inducible protein, suppresses prolonged NLRP3 inflammasome activation by clearance of damaged mitochondria through inducing mitophagy in macrophages. SESN2 plays a dual role in inducing mitophagy in response to inflammasome activation. First, SESN2 induces "mitochondrial priming" by marking mitochondria for recognition by the autophagic machinery. For mitochondrial preparing, SESN2 facilitates the perinuclear-clustering of mitochondria by mediating aggregation of SQSTM1 (sequestosome 1) and its binding to lysine 63 (Lys63)-linked ubiquitins on the mitochondrial surface. Second, SESN2 activates the specific autophagic machinery for degradation of primed mitochondria via an increase of ULK1 (unc-51 like kinase 1) protein levels. Moreover, increased SESN2 expression by extended LPS (lipopolysaccharide) stimulation is mediated by NOS2 (nitric oxide synthase 2, inducible)-mediated NO (nitric oxide) in macrophages. Thus, Sesn2-deficient mice displayed defective mitophagy, which resulted in hyperactivation of inflammasomes and increased mortality in 2 different sepsis models. Our findings define a unique regulatory mechanism of mitophagy activation for immunological homeostasis that protects the host from sepsis.

KEYWORDS:

NLRP3 inflammasome; SESN2; autophagy; mitochondrial priming; mitophagy; sepsis

PMID:
27337507
PMCID:
PMC4968237
DOI:
10.1080/15548627.2016.1183081
[Indexed for MEDLINE]
Free PMC Article

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