Disabled homolog 2 controls macrophage phenotypic polarization and adipose tissue inflammation
Samantha E. Adamson, Rachael Griffiths, Radim Moravec, Subramanian Senthivinayagam, Garren Montgomery, Wenshu Chen, Jenny Han, Poonam R. Sharma, Garrett R. Mullins, Stacey A. Gorski, Jonathan A. Cooper, Alexandra Kadl, Kyle Enfield, Thomas J. Braciale, Thurl E. Harris, Norbert Leitinger
Samantha E. Adamson, Rachael Griffiths, Radim Moravec, Subramanian Senthivinayagam, Garren Montgomery, Wenshu Chen, Jenny Han, Poonam R. Sharma, Garrett R. Mullins, Stacey A. Gorski, Jonathan A. Cooper, Alexandra Kadl, Kyle Enfield, Thomas J. Braciale, Thurl E. Harris, Norbert Leitinger
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Research Article Immunology

Disabled homolog 2 controls macrophage phenotypic polarization and adipose tissue inflammation

Abstract

Acute and chronic tissue injury results in the generation of a myriad of environmental cues that macrophages respond to by changing their phenotype and function. This phenotypic regulation is critical for controlling tissue inflammation and resolution. Here, we have identified the adaptor protein disabled homolog 2 (DAB2) as a regulator of phenotypic switching in macrophages. Dab2 expression was upregulated in M2 macrophages and suppressed in M1 macrophages isolated from both mice and humans, and genetic deletion of Dab2 predisposed macrophages to adopt a proinflammatory M1 phenotype. In mice with myeloid cell–specific deletion of Dab2 (Dab2fl/fl Lysm-Cre), treatment with sublethal doses of LPS resulted in increased proinflammatory gene expression and macrophage activation. Moreover, chronic high-fat feeding exacerbated adipose tissue inflammation, M1 polarization of adipose tissue macrophages, and the development of insulin resistance in DAB2-deficient animals compared with controls. Mutational analyses revealed that DAB2 interacts with TNF receptor–associated factor 6 (TRAF6) and attenuates IκB kinase β–dependent (IKKβ-dependent) phosphorylation of Ser536 in the transactivation domain of NF-κB p65. Together, these findings reveal that DAB2 is critical for controlling inflammatory signaling during phenotypic polarization of macrophages and suggest that manipulation of DAB2 expression and function may hold therapeutic potential for the treatment of acute and chronic inflammatory disorders.

Authors

Samantha E. Adamson, Rachael Griffiths, Radim Moravec, Subramanian Senthivinayagam, Garren Montgomery, Wenshu Chen, Jenny Han, Poonam R. Sharma, Garrett R. Mullins, Stacey A. Gorski, Jonathan A. Cooper, Alexandra Kadl, Kyle Enfield, Thomas J. Braciale, Thurl E. Harris, Norbert Leitinger

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Figure 2

Dab2 expression controls inflammatory gene expression.

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Dab2 expression controls inflammatory gene expression. qPCR analysis of...
qPCR analysis of Il1b (A) or Ptgs2 (B), which encodes cyclooxygenase 2, in RAW 264.7 macrophages treated with control media only (control) or 100 ng/ml LPS for 3 hours. Before treatment, RAW 264.7 macrophages were transfected with control or Dab2 siRNA for 48 hours. Results were normalized to B2m mRNA and are presented relative to control. (A and B) *P < 0.0001, by 2-way ANOVA with Tukey’s multiple comparisons test. Data represent the mean ± SEM of of 4 technical replicates and are representative of 2 independent experiments. (C and D) BMDMs from Dab2fl/fl and Dab2fl/fl Lysm-Cre mice were cultured in the presence of GM-CSF (5 ng/ml) for 2 days before treatment with LTA for 1 or 3 hours. Il6 (C) and Tnfa (D) mRNA levels were then measured by qPCR. (C and D) *P < 0.001, by 2-way ANOVA with Sidak’s multiple comparisons test. (E) qPCR analysis of Il1b in RAW 264.7 macrophages transfected with pCGT or pCGT-DAB2 and treated with 100 ng/ml LPS for 3 hours. *P < 0.05, by 2-tailed, unpaired Student’s t test. (F) Il1b mRNA expression was measured in RAW 264.7 macrophages transfected with pCGT, pCGT-p96-Dab2, or pCGT-p67-Dab2 and treated with increasing concentrations of LPS. *P < 0.0001, by 2-way ANOVA with Tukey’s multiple comparisons test. (G) Il1b mRNA expression was measured in RAW 264.7 macrophages transfected with pCGT, pCGT-p96-Dab2, or pCGT-p67-Dab2 and treated with IFN-γ or TNF-α. *P < 0.0001 compared with pCGT and #P < 0.0001 compared with control, by 2-way ANOVA with Tukey’s multiple comparisons test. Data represent the mean ± SEM of quadruplicate treatments.