ATF3 is a novel regulator of mouse neutrophil migration

ND Boespflug, S Kumar, JW McAlees… - Blood, The Journal …, 2014 - ashpublications.org
ND Boespflug, S Kumar, JW McAlees, JD Phelan, HL Grimes, K Hoebe, T Hai, MD Filippi…
Blood, The Journal of the American Society of Hematology, 2014ashpublications.org
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 …
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.
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