title: Microglial phenotype is regulated by activity of the transcription factor, NFAT (nuclear factor of activated T cells).
abstract: The transcription factor family, nuclear factor of activated T cells (NFAT), regulates immune cell phenotype. Four different calcium/calmodulin-regulated isoforms have been identified in the periphery, but isoform expression in microglia, the resident immune cells of the CNS, has not been fully defined. In this study microglial NFAT isoform expression and involvement in regulating inflammatory responses in murine primary microglia culture was examined. Western blot analysis demonstrated robust detection of NFATc1 and c2 isoforms in microglia. Electrophoretic mobility shift assays demonstrated increased NFAT-DNA binding from nuclear extracts of lipopolysaccharide (LPS) stimulated microglia. Moreover, LPS-stimulated microglia behaved similarly to T cell receptor agonist antibody-stimulated Jurkat cells demonstrating a transient increase in NFAT-driven luciferase reporter gene expression. LPS-induced NFAT-luciferase activity in microglia was attenuated by pretreatment with tat-VIVIT, a cell-permeable NFAT inhibitory peptide. Furthermore, LPS-mediated secretion of microglial cytokines, TNF-alpha and MCP-1, was decreased by treatment with tat-VIVIT but not with tat-VEET, a negative control peptide. These results demonstrate that NFAT plays a role in regulating proinflammatory responses in cultured murine microglia.
authors.affiliation: Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203-9037, USA.
authors.forename: Kumi
authors.initials: K
authors.lastname: Nagamoto-Combs
authors.forename: Colin K
authors.initials: CK
authors.lastname: Combs
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D016207:Cytokines / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D004797:Enzyme-Linked Immunosorbent Assay; D051379:Mice; D017628:Microglia / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D050778:NFATC Transcription Factors / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D010641:Phenotype; D020033:Protein Isoforms / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism
chemical_list: D016207:Cytokines; D050778:NFATC Transcription Factors; D020033:Protein Isoforms