MafB antagonizes phenotypic alteration induced by GM-CSF in microglia

Journal Article · Fri Jul 17 04:00:00 EDT 2015 · Biochemical and Biophysical Research Communications

DOI:https://doi.org/10.1016/J.BBRC.2015.05.036· OSTI ID:22462113

Koshida, Ryusuke; Oishi, Hisashi; Hamada, Michito; Takahashi, Satoru

Microglia are tissue-resident macrophages which are distributed throughout the central nervous system (CNS). Recent studies suggest that microglia are a unique myeloid population distinct from peripheral macrophages in terms of origin and gene expression signature. Granulocyte-macrophage colony-stimulating factor (GM-CSF), a pleiotropic cytokine regulating myeloid development, has been shown to stimulate proliferation and alter phenotype of microglia in vitro. However, how its signaling is modulated in microglia is poorly characterized. MafB, a bZip transcriptional factor, is highly expressed in monocyte-macrophage lineage cells including microglia, although its role in microglia is largely unknown. We investigated the crosstalk between GM-CSF signaling and MafB by analyzing primary microglia. We found that Mafb-deficient microglia grew more rapidly than wild-type microglia in response to GM-CSF. Moreover, the expression of genes associated with microglial differentiation was more downregulated in Mafb-deficient microglia cultured with GM-CSF. Notably, such differences between the genotypes were not observed in the presence of M-CSF. In addition, we found that Mafb-deficient microglia cultured with GM-CSF barely extended their membrane protrusions, probably due to abnormal activation of RhoA, a key regulator of cytoskeletal remodeling. Altogether, our study reveals that MafB is a negative regulator of GM-CSF signaling in microglia. These findings could provide new insight into the modulation of cytokine signaling by transcription factors in microglia. - Highlights: • GM-CSF alters the phenotype of microglia in vitro more potently than M-CSF. • Transcription factor MafB antagonizes the effect of GM-CSF on microglia in vitro. • MafB deficiency leads to RhoA activation in microglia in response to GM-CSF. • We show for the first time the function of MafB in microglia.

• OSTI ID: 22462113
• Journal Information: Biochemical and Biophysical Research Communications, Journal Name: Biochemical and Biophysical Research Communications Journal Issue: 1-2 Vol. 463; ISSN BBRCA9; ISSN 0006-291X
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
ANIMAL TISSUES
CENTRAL NERVOUS SYSTEM
GENES
GENOTYPE
IN VITRO
MACROPHAGES
MEMBRANES
MONOCYTES
ORIGIN
PHENOTYPE
SIGNALS
TRANSCRIPTION FACTORS