title: Kinase AKT1 negatively controls neutrophil recruitment and function in mice.
abstract: Neutrophils are critically involved in host defense and inflammatory injury. However, intrinsic signaling mechanisms controlling neutrophil recruitment and activities are poorly defined. In this article, we showed that protein kinase AKT1 (also known as PKBα) is the dominant isoform expressed in neutrophils and is downregulated upon bacterial infection and neutrophil activation. AKT1 deficiency resulted in severe disease progression accompanied by recruitment of neutrophils and enhanced bactericidal activity in the acute inflammatory lung injury (ALI) and the Staphylococcus aureus infection mouse models. Moreover, the depletion of neutrophils efficiently reversed the aggravated inflammatory response, but adoptive transfer of AKT1(-/-) neutrophils could potentiate the inflammatory immunity, indicating an intrinsic effect of the neutrophil in modulating inflammation in AKT1(-/-) mice. In the ALI model, the infiltration of neutrophils into the inflammatory site was associated with enhanced migration capacity, whereas inflammatory stimuli could promote neutrophil apoptosis. In accordance with these findings, neutralization of CXCR2 attenuated neutrophil infiltration and delayed the occurrence of inflammation. Finally, the enhanced bactericidal activity and inflammatory immunity of AKT-deficient neutrophils were mediated by a STAT1-dependent, but not a mammalian target of rapamycin-dependent, pathway. Thus, our findings indicated that the AKT1-STAT1 signaling axis negatively regulates neutrophil recruitment and activation in ALI and S. aureus infection in mice.
authors.affiliation: Department of Immunology, Shanghai Medical College, Fudan University, Shanghai 200023, People's Republic of China. liugw@fudan.edu.cn
authors.forename: Guangwei
authors.initials: G
authors.lastname: Liu
authors.forename: Yujing
authors.initials: Y
authors.lastname: Bi
authors.forename: Ruoning
authors.initials: R
authors.lastname: Wang
authors.forename: Bo
authors.initials: B
authors.lastname: Shen
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Hui
authors.initials: H
authors.lastname: Yang
authors.forename: Xiao
authors.initials: X
authors.lastname: Wang
authors.forename: Huanrong
authors.initials: H
authors.lastname: Liu
authors.forename: Yun
authors.initials: Y
authors.lastname: Lu
authors.forename: Fei
authors.initials: F
authors.lastname: Han
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D005434:Flow Cytometry; D015151:Immunoblotting; D007249:Inflammation / Q000276:immunology* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018375:Neutrophil Activation / Q000276:immunology; D020556:Neutrophil Infiltration / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology* / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000276:immunology* / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D050794:STAT1 Transcription Factor / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology; D013203:Staphylococcal Infections / Q000276:immunology*
chemical_list: D050794:STAT1 Transcription Factor; C514862:Akt1 protein, mouse; D051057:Proto-Oncogene Proteins c-akt