Abstract

The appearance in the circulation of lipopolysaccharide (LPS) is associated with sepsis and a greatly increased risk of neutrophil- mediated lung injury. The mechanisms by which neutrophils respond to LPS remain poorly understood, but the result is all too often sequestration in the pulmonary microcirculation and injury to the endothelium. We suggest here that these responses must eventually be understood in terms of the signalling cascades activated, and have focused on those resulting in activation of MAP kinases. Using both human and mouse systems, and a combined biochemical/genetic approach, our specific aims are: 1) To determine the signalling pathways used in response to LPS in the human and murine neutrophil, testing the hypothesis that LPS exposure will activate the tyrosine kinases Syk and Lyn leading to downstream activity of an MEKK, MKK3/6, and distinct p38 isoforms. 2) Determine the mechanisms by which p38 MAP kinases regulate translation of TNFalpha in neutrophils, with the hypothesis that specific p38 isoforms are essential in regulating translation of TNFalpha message by phosphorylating eIF-4E and increasing its affinity for the tranlsational complex. 3) To determine the mechanisms by which exposure of neutrophils to TNFalpha leads to activation of Jun-N- terminal kinases (JNKs), testing the hypothesis that exposure to TNFalpha in the context of integrin ligation leads to activation of Syk, Fgr, and Hck tyrosine kinases and downstream activation of MEKK1, MKK4, and JNK, which by phosphorylating c-Jun, allows induction of AP1- dependent genes, including MCP-1, to attract monocytes. 4) To determine the contribution of these pathways and feedback loops to neutrophil sequestration in the lung and subsequent injury. These studies will provide new information on the mechanisms by which the neutrophil responds to LPS with a complex repertoire of signalling cascades. Understanding this process may allow design of novel strategies for minimization of lung injury.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
1R01HL061407-01
Application #
2730651
Study Section
Lung Biology and Pathology Study Section (LBPA)
Project Start
1998-12-07
Project End
2002-11-30
Budget Start
1998-12-07
Budget End
1999-11-30
Support Year
1
Fiscal Year
1999
Total Cost
Indirect Cost

  Institution

Name
National Jewish Health
Department
Type
DUNS #
City
Denver
State
CO
Country
United States
Zip Code
80206

  Publications

Zemans, Rachel L; Briones, Natalie; Young, Scott K et al. (2009) A novel method for long term bone marrow culture and genetic modification of murine neutrophils via retroviral transduction. J Immunol Methods 340:102-15
Smoak, Kathleen; Madenspacher, Jennifer; Jeyaseelan, Samithamby et al. (2008) Effects of liver X receptor agonist treatment on pulmonary inflammation and host defense. J Immunol 180:3305-12
Fessler, Michael B; Arndt, Patrick G; Just, Ingo et al. (2007) Dual role for RhoA in suppression and induction of cytokines in the human neutrophil. Blood 109:1248-56
Arndt, Patrick G; Young, Scott K; Poch, Katie R et al. (2006) Systemic inhibition of the angiotensin-converting enzyme limits lipopolysaccharide-induced lung neutrophil recruitment through both bradykinin and angiotensin II-regulated pathways. J Immunol 177:7233-41
Walker, Travis S; Tomlin, Kerry L; Worthen, G Scott et al. (2005) Enhanced Pseudomonas aeruginosa biofilm development mediated by human neutrophils. Infect Immun 73:3693-701
Arndt, Patrick G; Young, Scott K; Lieber, Jonathan G et al. (2005) Inhibition of c-Jun N-terminal kinase limits lipopolysaccharide-induced pulmonary neutrophil influx. Am J Respir Crit Care Med 171:978-86
Fessler, Michael B; Young, Scott K; Jeyaseelan, Samithamby et al. (2005) A role for hydroxy-methylglutaryl coenzyme a reductase in pulmonary inflammation and host defense. Am J Respir Crit Care Med 171:606-15
Fessler, Michael B; Arndt, Patrick G; Frasch, S Courtney et al. (2004) Lipid rafts regulate lipopolysaccharide-induced activation of Cdc42 and inflammatory functions of the human neutrophil. J Biol Chem 279:39989-98
Malcolm, Kenneth C; Worthen, G Scott (2003) Lipopolysaccharide stimulates p38-dependent induction of antiviral genes in neutrophils independently of paracrine factors. J Biol Chem 278:15693-701
Avdi, Natalie J; Malcolm, Kenneth C; Nick, Jerry A et al. (2002) A role for protein phosphatase-2A in p38 mitogen-activated protein kinase-mediated regulation of the c-Jun NH(2)-terminal kinase pathway in human neutrophils. J Biol Chem 277:40687-96

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