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Protein kinase A inhibition of macrophage maturation is accompanied by an increase in DNA methylation of the colony‐stimulating factor 1 receptor gene
Author(s) -
Zasłona Zbigniew,
Scruggs Anne M.,
PetersGolden Marc,
Huang Steven K.
Publication year - 2016
Publication title -
immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.297
H-Index - 133
eISSN - 1365-2567
pISSN - 0019-2805
DOI - 10.1111/imm.12641
Subject(s) - dna methylation , macrophage colony stimulating factor , biology , protein kinase a , microbiology and biotechnology , gene expression , methylation , transcription factor , kinase , macrophage , gene , biochemistry , in vitro
Summary Macrophage colony‐stimulating factor 1 ( CSF ‐1) plays a critical role in the differentiation of mononuclear phagocytes from bone marrow precursors, and maturing monocytes and macrophages exhibit increased expression of the CSF ‐1 receptor, CSF 1R. The expression of CSF 1R is tightly regulated by transcription factors and epigenetic mechanisms. We previously showed that prostaglandin E 2 and subsequent activation of protein kinase A ( PKA ) inhibited CSF 1R expression and macrophage maturation. Here, we examine the DNA methylation changes that occur at the Csf1r locus during macrophage maturation in the presence or absence of activated PKA . Murine bone marrow cells were matured to macrophages by incubating cells with CSF ‐1‐containing conditioned medium for up to 6 days in the presence or absence of the PKA agonist 6‐bnz‐ cAMP . DNA methylation of Csf1r promoter and enhancer regions was assayed by bisulphite pyrosequencing. DNA methylation of Csf1r decreased during normal macrophage maturation in concert with an increase in Csf1r mRNA expression. Treatment with the PKA agonist inhibited Csf1r mRNA and protein expression, and increased DNA methylation at the Csf1r promoter. This was associated with decreased binding of the transcription factor PU .1 to the Csf1r promoter. Treatment with the PKA agonist inhibited the responsiveness of macrophages to CSF ‐1. Levels of endogenous PKA activity decreased during normal macrophage maturation, suggesting that attenuation of this signalling pathway contributes to the increase in CSF 1R expression during macrophage maturation. Together, these results demonstrate that macrophage maturation is accompanied by Csf1r hypomethylation, and illustrates for the first time the ability of PKA to increase Csf1r DNA methylation.