TY - JOUR
T1 - Mincle-mediated neutrophil extracellular trap formation by regulation of autophagy
AU - Sharma, Atul
AU - Simonson, Tanner J.
AU - Jondle, Christopher N.
AU - Mishra, Bibhuti B.
AU - Sharma, Jyotika
N1 - Publisher Copyright:
©The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved.
PY - 2017/4/1
Y1 - 2017/4/1
N2 - Background. Neutrophil extracellular traps (NETs) constitute antimicrobial function of neutrophils but have also been linked to perpetuation of inflammation. Despite this evident physiological relevance, mechanistic understanding of NET formation is poor. In this study, we examined the mechanism by which Mincle, a C-type lectin receptor, regulates NET formation. Methods. NET formation, reactive oxygen species, autophagy activation and intracellular signaling pathways were analyzed in Mincle-sufficient and -deficient neutrophils stimulated in vitro with various stimuli and in vivo during Klebsiella infection. Results. We found that Mincle mediates NET formation in response to several activation stimuli in vitro and in vivo during pneumoseptic infection with Klebsiella pneumoniae, indicating its regulatory role in NET formation. Mechanistically, we show that attenuated NET formation in Mincle-/- neutrophils correlates with an impaired autophagy activation in vitro and in vivo, whereas reactive oxygen species (ROS) formation in these neutrophils remained intact. The requirement of autophagy in Mincle-mediated NET formation was further supported by exogenous treatment with autophagy inducer tamoxifen, which rescued the NET formation defect in Mincle-/- neutrophils. Conclusions. Our findings identify a previously unrecognized role of Mincle as a regulator of autophagy, which mediates NET formation without affecting ROS generation. Our study addresses a major challenge in the field by positing this pathway to be targeted for modulation of NETs while preserving ROS production, an important innate immune defense.
AB - Background. Neutrophil extracellular traps (NETs) constitute antimicrobial function of neutrophils but have also been linked to perpetuation of inflammation. Despite this evident physiological relevance, mechanistic understanding of NET formation is poor. In this study, we examined the mechanism by which Mincle, a C-type lectin receptor, regulates NET formation. Methods. NET formation, reactive oxygen species, autophagy activation and intracellular signaling pathways were analyzed in Mincle-sufficient and -deficient neutrophils stimulated in vitro with various stimuli and in vivo during Klebsiella infection. Results. We found that Mincle mediates NET formation in response to several activation stimuli in vitro and in vivo during pneumoseptic infection with Klebsiella pneumoniae, indicating its regulatory role in NET formation. Mechanistically, we show that attenuated NET formation in Mincle-/- neutrophils correlates with an impaired autophagy activation in vitro and in vivo, whereas reactive oxygen species (ROS) formation in these neutrophils remained intact. The requirement of autophagy in Mincle-mediated NET formation was further supported by exogenous treatment with autophagy inducer tamoxifen, which rescued the NET formation defect in Mincle-/- neutrophils. Conclusions. Our findings identify a previously unrecognized role of Mincle as a regulator of autophagy, which mediates NET formation without affecting ROS generation. Our study addresses a major challenge in the field by positing this pathway to be targeted for modulation of NETs while preserving ROS production, an important innate immune defense.
KW - Autophagy
KW - Bacterial infection
KW - Innate immune response
KW - Klebsiella pneumoniae
KW - Mincle
KW - Neutrophil extracellular traps (NETs)
KW - Pneumonia
KW - Reactive oxygen species
KW - Sepsis
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U2 - 10.1093/infdis/jix072
DO - 10.1093/infdis/jix072
M3 - Article
C2 - 28186242
AN - SCOPUS:85020165244
SN - 0022-1899
VL - 215
SP - 1040
EP - 1048
JO - Journal of Infectious Diseases
JF - Journal of Infectious Diseases
IS - 7
ER -