Abstract 13424: GATA3 Regulates Macrophage Polarization and Phenotype
Background: Macrophage polarization is believed to play important role in inflammation and in host defense mechanisms. While the distinct functions attributable to M1 and M2 macrophages have been intensively studied, the underlying mechanism that controls macrophage polarization is incompletely understood.
Methods: We used flow cytometry, immunofluorescence microscopy, qPCR, promoter activity and retroviral transfection studies to assess the expression/function of GATA3 in macrophages in vitro and in vivo using apo E-/- and wild type mice.
Results: FACS analysis identified CD11b+F4/80+GATA3+ cells in the bone marrow, spleen, and liver of apo E-/- and wild type mice. A significant reduction in the number of bone marrow GATA3+ macrophages (p=0.02) was seen after feeding apo E -/- mice an atherogenic diet for 10 or 20 weeks. In contrast, apo E-/- mice fed an atherogenic diet for either 10 or 20 weeks had a significantly greater number of GATA3+ macrophages in their spleens, compared to control mice (p=0.003) and this was observed again in the liver (p=0.009). The presence of CD11b+/F4/80+/GATA3+ cells in the bone marrow, spleen, and liver of C57BL/6 mice was further confirmed by immunofluorescence staining. Flow cytometry analysis of bone marrow macrophages showed that while presence and absence of GATA3 had no effect on the expression of M1 macrophage markers (CD80/TLR2/TLR4), the expression of M2 markers (CD23 and IL4R) were significantly higher in F4/80+/GATA3+ cells. qPCR analysis of bone marrow- and peritoneal-derived macrophages treated with either IL-4 or cholesterol crystals showed marked induction of GATA3 mRNA in response to the treatment. In addition, IFNγ-induced upregulation of MCP-1 and IL-10 in monocytic cells is blocked by GATA3. Furthermore, the treatment of mouse monocytic cell line with GATA3 shRNA markedly down-regulated expression of Arg-1 induced by IL-4. Retroviral expression of GATA3 in mouse monocytic cell line markedly down regulated expression of MCP-1, TNFα, CD206 mRNAs whereas it significantly induced expression of Arg1, IL-6, and iNOS.
Conclusions: These data identify GATA3 as a novel regulator of macrophage polarization and phenotype.
- © 2012 by American Heart Association, Inc.