Regulation of systemic and local neutrophil responses by G-CSF during pulmonary Pseudomonas aeruginosa infection

Blood. 2007 Apr 15;109(8):3235-43. doi: 10.1182/blood-2005-01-015081. Epub 2006 Dec 21.

Abstract

Granulocyte colony-stimulating factor (G-CSF) regulates the production, maturation, and function of neutrophils. Its expression is often induced during infection, resulting in high concentrations of G-CSF in inflammatory exudates and in the blood, suggesting that it may regulate both local and systemic neutrophil responses. Herein, we characterize the neutrophil response in G-CSFR(-/-) mice following intratracheal injection with Pseudomonas aeruginosa-laden agarose beads, modeling the pulmonary infection observed in many patients with cystic fibrosis. G-CSFR(-/-) mice are markedly susceptible to bronchopulmonary P aeruginosa infection, exhibiting decreased survival and bacterial clearance as well as extensive damage to lung tissue. The systemic neutrophil response was mediated primarily by enhanced neutrophil release from the bone marrow rather than increased neutrophil production and was attenuated in G-CSFR(-/-) mice. Despite normal to increased local production of inflammatory chemokines, neutrophil accumulation into the infected lung of G-CSFR(-/-) mice was markedly reduced. Moreover, the percentage of apoptotic neutrophils in the lung was elevated, suggesting that G-CSF signals may play an important role in regulating neutrophil survival at the inflammatory site. Collectively, these data provide new evidence that G-CSF signals play important but specific roles in the regulation of the systemic and local neutrophil response following infection.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / genetics
  • Bone Marrow / metabolism
  • Bone Marrow / pathology
  • Cell Survival / genetics
  • Chemokines / metabolism
  • Cystic Fibrosis / complications
  • Cystic Fibrosis / metabolism
  • Cystic Fibrosis / microbiology
  • Cystic Fibrosis / pathology
  • Granulocyte Colony-Stimulating Factor / metabolism*
  • Humans
  • Inflammation / metabolism
  • Inflammation / microbiology
  • Inflammation / pathology
  • Male
  • Mice
  • Mice, Knockout
  • Neutrophil Infiltration* / genetics
  • Neutrophils / metabolism*
  • Neutrophils / pathology
  • Pneumonia, Bacterial / etiology
  • Pneumonia, Bacterial / metabolism*
  • Pneumonia, Bacterial / pathology
  • Pseudomonas Infections / etiology
  • Pseudomonas Infections / metabolism*
  • Pseudomonas Infections / pathology
  • Pseudomonas aeruginosa
  • Receptors, Granulocyte Colony-Stimulating Factor / deficiency
  • Receptors, Granulocyte Colony-Stimulating Factor / metabolism

Substances

  • Chemokines
  • Receptors, Granulocyte Colony-Stimulating Factor
  • Granulocyte Colony-Stimulating Factor