MOLECULAR MECHANISMS OF LEUKOCYTE ACTIVATION

Summary

Principal Investigator: Richard Ye
Affiliation: University of Illinois at Chicago
Country: USA
Abstract: DESCRIPTION (provided by applicant): Chemoattractant-induced phagocyte activation is an important mechanism of host defense. In phagocytes, induced activation of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase leads to robust production of reactive oxygen species (ROS), which is essential for the elimination of ingested bacteria and fungi. However, extracellular ROS production by phagocyte NADPH oxidase (also termed Nox2) can be harmful to the tissue and is a major cause of vascular injury in acute inflammation. This revised competing renewal application aims to understand how chemoattractant-induced neutrophil superoxide generation is regulated at the molecular and cellular levels. Building on the systems we developed and preliminary results obtained in the previous grant cycle, the application will focus on the critical roles for p47phox in the assembly of an NADPH oxidase. Experiments are proposed in 3 specific aims to challenge existing concept and identify novel regulatory mechanisms for NADPH oxidase activation. Aim 1 will characterize Akt isoforms in chemoattractant-induced ROS production. In neutrophil research, Akt has been taken as one class of protein kinases functionally, but our preliminary study has led to an unexpected finding that the two major Akt isoforms in neutrophils play different roles in NADPH oxidase activation. Experiments are proposed to test the hypothesis that membrane translocation of an Akt isoform dictates its ability to mediate NADPH oxidase activation, and to examine whether the two Akt isoforms phosphorylates p47phox differently. Aim 2 is based on our recent characterization of a mutant p47phox protein that mediates spontaneous superoxide production in the absence of physical interaction with p67phox. Experiments are designed to characterize a potentially novel mechanism for 47phox-mediated conformational change in cytochrome b558 that facilitates the assembly of a functional NADPH oxidase complex. Aim 3 will investigate an important regulatory mechanism for p47phox-dependent oxidant production. We will examine the negative regulation of NADPH oxidase by MAP kinase phosphatase 5 (MKP5). Using in vivo and ex vivo approaches, we will investigate how MKP5 protects against LPS-induced vascular injury through suppression of neutrophil ROS production in a mouse model of vascular inflammation. Collectively, these studies are expected to provide novel insights into the activation and inactivation mechanisms of phagocyte NADPH oxidase, thereby facilitating therapeutic intervention of ROS-mediated tissue injury. PUBLIC HEALTH RELEVANCE: Phagocytes (a class of white blood cells that engulf bacteria and fungi) produce large amounts of reactive oxygen species that are toxic to bacteria and to host tissues. A balanced act of phagocyte activation is important for the maintenance of host defense capability and for minimizing unwanted tissue injury. The proposed studies will investigate how these cells are regulated by intrinsic mechanisms that prevent over-production of reactive oxygen species during acute inflammation, and how the machinery for oxidant production is assembled and activated when phagocytes are stimulated. Information derived from these studies is expected to have health benefit by reducing inflammatory tissue injury and the resulting failure of organ functions.
Funding Period: ----------------1993 - ---------------2015-
more information: NIH RePORT

Top Publications

  1. pmc Serum amyloid A induces interleukin-33 expression through an IRF7-dependent pathway
    Lei Sun
    School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
    Eur J Immunol 44:2153-64. 2014
  2. pmc Jmjd3-mediated epigenetic regulation of inflammatory cytokine gene expression in serum amyloid A-stimulated macrophages
    Qian Yan
    School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, P R China
    Cell Signal 26:1783-91. 2014
  3. pmc STIM1 for stimulation of phagocyte NADPH oxidase
    Richard D Ye
    Shanghai Jiao Tong University
    Blood 123:2129-30. 2014
  4. pmc Chemerin C9 peptide induces receptor internalization through a clathrin-independent pathway
    Jun Xian Zhou
    School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
    Acta Pharmacol Sin 35:653-63. 2014
  5. pmc Structural determinants for the interaction of formyl peptide receptor 2 with peptide ligands
    Hui Qiong He
    From the School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
    J Biol Chem 289:2295-306. 2014
  6. pmc A critical role for phosphatidylinositol (3,4,5)-trisphosphate-dependent Rac exchanger 1 in endothelial junction disruption and vascular hyperpermeability
    Ram P Naikawadi
    Department of Pharmacology, University of Illinois College of Medicine, Chicago, IL 60612, USA
    Circ Res 111:1517-27. 2012
  7. pmc The Akt1 isoform is required for optimal IFN-β transcription through direct phosphorylation of β-catenin
    Benjamin N Gantner
    Department of Pharmacology, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA
    J Immunol 189:3104-11. 2012
  8. pmc Protective role of reactive oxygen species in endotoxin-induced lung inflammation through modulation of IL-10 expression
    Jing Deng
    Section of Pulmonary, Critical Care, Sleep, and Allergy, Department of Medicine, University of Illinois, Chicago, IL 60612, USA
    J Immunol 188:5734-40. 2012
  9. pmc LIM kinase 1 promotes endothelial barrier disruption and neutrophil infiltration in mouse lungs
    Matvey Gorovoy
    Department of Pharmacology, University of Illinois at Chicago, 909 S Wolcott Ave, Chicago, IL 60612, USA
    Circ Res 105:549-56. 2009
  10. pmc Characterization of P-Rex1 for its role in fMet-Leu-Phe-induced superoxide production in reconstituted COS(phox) cells
    Baoming Nie
    Department of Pharmacology, University of Illinois, Chicago, 60612, United States
    Cell Signal 22:770-82. 2010

Detail Information

Publications12

  1. pmc Serum amyloid A induces interleukin-33 expression through an IRF7-dependent pathway
    Lei Sun
    School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
    Eur J Immunol 44:2153-64. 2014
    ..SAA also promoted an interaction between TNF receptor-associated factor 6 and IRF7. Taken together, these results identify IRF7 as a critical transcription factor for SAA-induced Il33 expression in monocytes and macrophages. ..
  2. pmc Jmjd3-mediated epigenetic regulation of inflammatory cytokine gene expression in serum amyloid A-stimulated macrophages
    Qian Yan
    School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, P R China
    Cell Signal 26:1783-91. 2014
    ..This mechanism may be subject to therapeutic intervention for sterile inflammation and atherosclerosis. ..
  3. pmc STIM1 for stimulation of phagocyte NADPH oxidase
    Richard D Ye
    Shanghai Jiao Tong University
    Blood 123:2129-30. 2014
    ....
  4. pmc Chemerin C9 peptide induces receptor internalization through a clathrin-independent pathway
    Jun Xian Zhou
    School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
    Acta Pharmacol Sin 35:653-63. 2014
    ..The aim of this work was to investigate how CMKLR1 was internalized and whether its internalization affected cell signaling in vitro...
  5. pmc Structural determinants for the interaction of formyl peptide receptor 2 with peptide ligands
    Hui Qiong He
    From the School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
    J Biol Chem 289:2295-306. 2014
    ..These results indicate that different structural determinants are used by FPR1 and FPR2 to interact with formyl peptides. ..
  6. pmc A critical role for phosphatidylinositol (3,4,5)-trisphosphate-dependent Rac exchanger 1 in endothelial junction disruption and vascular hyperpermeability
    Ram P Naikawadi
    Department of Pharmacology, University of Illinois College of Medicine, Chicago, IL 60612, USA
    Circ Res 111:1517-27. 2012
    ..Understanding the upstream pathway may delineate Rac activation mechanisms and its role in maintaining vascular endothelial barrier integrity...
  7. pmc The Akt1 isoform is required for optimal IFN-β transcription through direct phosphorylation of β-catenin
    Benjamin N Gantner
    Department of Pharmacology, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA
    J Immunol 189:3104-11. 2012
    ..Taken together, these results demonstrate that the Akt1 isoform is required for β-catenin-mediated promotion of IFN-β transcription downstream of TLR3 activation...
  8. pmc Protective role of reactive oxygen species in endotoxin-induced lung inflammation through modulation of IL-10 expression
    Jing Deng
    Section of Pulmonary, Critical Care, Sleep, and Allergy, Department of Medicine, University of Illinois, Chicago, IL 60612, USA
    J Immunol 188:5734-40. 2012
    ..Our data support the innovative concept that generation of ROS is essential for counterregulation of acute lung inflammation...
  9. pmc LIM kinase 1 promotes endothelial barrier disruption and neutrophil infiltration in mouse lungs
    Matvey Gorovoy
    Department of Pharmacology, University of Illinois at Chicago, 909 S Wolcott Ave, Chicago, IL 60612, USA
    Circ Res 105:549-56. 2009
    ..Recently we reported that endotoxin induced activation of RhoA in mice lungs that led to the disruption of endothelial barrier and lung edema formation; however, the molecular mechanism of this phenomenon remained unknown...
  10. pmc Characterization of P-Rex1 for its role in fMet-Leu-Phe-induced superoxide production in reconstituted COS(phox) cells
    Baoming Nie
    Department of Pharmacology, University of Illinois, Chicago, 60612, United States
    Cell Signal 22:770-82. 2010
    ..These results demonstrate that in COS(phox) cells, P-Rex1 is a critical component for FPR1-mediated signaling leading to NADPH oxidase activation, and there is a crosstalk between the P-Rex1-Rac pathway and Akt in superoxide generation...
  11. pmc A non-redundant role for MKP5 in limiting ROS production and preventing LPS-induced vascular injury
    Feng Qian
    Department of Pharmacology, University of Illinois College of Medicine, Chicago, IL, USA
    EMBO J 28:2896-907. 2009
    ..Collectively, these results show an earlier unrecognized and non-redundant function of MKP5 in restraining p38 MAPK-mediated neutrophil oxidant production, thereby preventing LPS-induced vascular injury...
  12. pmc Opposing effects of platelet-activating factor and lyso-platelet-activating factor on neutrophil and platelet activation
    Emily J Welch
    Department of Pharmacology, University of Illinois College of Medicine, Chicago, IL 60612, USA
    Mol Pharmacol 75:227-34. 2009
    ..These findings identify lysoPAF as a bioactive lipid with opposing functions of PAF and suggest a novel and intrinsic regulatory mechanism for balance of the potent activity of PAF...