ATF3 is a novel regulator of mouse neutrophil migration

Blood. 2014 Mar 27;123(13):2084-93. doi: 10.1182/blood-2013-06-510909. Epub 2014 Jan 27.

Abstract

Expression of the activating transcription factor 3 (ATF3) gene is induced by Toll-like receptor (TLR) signaling. In turn, ATF3 protein inhibits the expression of various TLR-driven proinflammatory genes. Given its counter-regulatory role in diverse innate immune responses, we defined the effects of ATF3 on neutrophilic airway inflammation in mice. ATF3 deletion was associated with increased lipopolysaccharide (LPS)-driven airway epithelia production of CXCL1, but not CXCL2, findings concordant with a consensus ATF3-binding site identified solely in the Cxcl1 promoter. Unexpectedly, ATF3-deficient mice did not exhibit increased airway neutrophilia after LPS challenge. Bone marrow chimeras revealed a specific reduction in ATF3(-/-) neutrophil recruitment to wild-type lungs. In vitro, ATF3(-/-) neutrophils exhibited a profound chemotaxis defect. Global gene expression analysis identified ablated Tiam2 expression in ATF3(-/-) neutrophils. TIAM2 regulates cellular motility by activating Rac1-mediated focal adhesion disassembly. Notably, ATF3(-/-) and ATF3-sufficient TIAM2 knockdown neutrophils, both lacking TIAM2, exhibited increased focal complex area, along with excessive CD11b-mediated F-actin polymerization. Together, our data describe a dichotomous role for ATF3-mediated regulation of neutrophilic responses: inhibition of neutrophil chemokine production but promotion of neutrophil chemotaxis.

Publication types

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

MeSH terms

  • Activating Transcription Factor 3 / genetics
  • Activating Transcription Factor 3 / physiology*
  • Animals
  • Cells, Cultured
  • Chemokine CXCL1 / metabolism
  • Immune System Diseases / genetics*
  • Leukocyte Disorders / genetics*
  • Lipopolysaccharides / pharmacology
  • Lung / cytology
  • Lung / immunology
  • Lung / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Neutrophil Infiltration / genetics
  • Respiratory Mucosa / drug effects
  • Respiratory Mucosa / metabolism

Substances

  • Activating Transcription Factor 3
  • Atf3 protein, mouse
  • Chemokine CXCL1
  • Lipopolysaccharides

Supplementary concepts

  • Neutrophil Chemotactic Response, Abnormal