Macrophage-specific MHCII expression is regulated by a remote Ciita enhancer controlled by NFAT5

Abstract

MHCII in antigen-presenting cells (APCs) is a key regulator of adaptive immune responses. Expression of MHCII genes is controlled by the transcription coactivator CIITA, itself regulated through cell type–specific promoters. Here we show that the transcription factor NFAT5 is needed for expression of Ciita and MHCII in macrophages, but not in dendritic cells and other APCs. NFAT5-deficient macrophages showed defective activation of MHCII-dependent responses in CD4+ T lymphocytes and attenuated capacity to elicit graft rejection in vivo. Ultrasequencing analysis of NFAT5-immunoprecipitated chromatin uncovered an NFAT5-regulated region distally upstream of Ciita. This region was required for CIITA and hence MHCII expression, exhibited NFAT5-dependent characteristics of active enhancers such as H3K27 acetylation marks, and required NFAT5 to interact with Ciita myeloid promoter I. Our results uncover an NFAT5-regulated mechanism that maintains CIITA and MHCII expression in macrophages and thus modulates their T lymphocyte priming capacity.

HIF1A and NFAT5 coordinate Na+-boosted antibacterial defense via enhanced autophagy and autolysosomal targeting

“…The transcription factor NFAT5 plays a key role in the adaption of various cells to increases in extracellular Na + levels [5][6][7]. Moreover, NFAT5 plays also an important role in MΦ immunobiology under standard cell culture conditions [8][9][10][11]. High salt conditions increased NFAT5 levels in MΦ, and resulted in improved antiparasitic control of Leishmania major infection both in vitro and in vivo [1].…”

The transcription factor NFAT5 limits infection-induced type I interferon responses

“…This region included various Ifna genes and Ifnb1 . As the Ifnb1 promoter contains a clear consensus binding site for NFAT5 (5′-AGGAAAA-3′), for which we already had evidence of NFAT5 recruitment (see below), we suspected that the ChIP-sequencing assay was not sufficiently sensitive to detect some NFAT5-bound regions, as we had already noticed in a recent work (Buxadé et al, 2018).…”

“…Nfat5 +/− heterozygous mice in a pure 129/sv background were crossed to obtain Nfat5 −/− and Nfat5 +/+ littermates as described (Buxadé et al, 2012). Nfat5 -floxed ( Nfat5 fl/fl ) mice in a pure C57BL/6 background were crossed with LysM-Cre mice to obtain mice lacking Nfat5 in myeloid cells, and with Vav-Cre mice to obtain mice lacking NFAT5 in immune cell lineages (Buxadé et al, 2018). LysM-Cre mice were purchased from The Jackson Laboratory (Cat# 004781), and Vav-Cre mice were kindly provided by Dr. Thomas Graf (Center for Genomic Regulation, Barcelona, Spain).…”

“…For functional assays, BMDMs were harvested with PBS plus 5 mM EDTA by gentle pipetting, washed with PBS, and plated (10 6 cells/3 ml/well) in tissue culture plates. BMDCs were obtained by culturing bone marrow cell suspensions in 10% GM-CSF–supplemented medium for 10 d (Buxadé et al, 2018). In addition, Flt3L-induced conventional and pDCs were generated by culturing bone marrow cell suspensions in 200 ng/ml Flt3L (ImmunoTools, Cat# 12343305) for 10 d, after which BMDCs were isolated by flow cytometry cell sorting into CD11c + B220 − (conventional BMDCs) and CD11c + B220 + (plasmacytoid BMDCs).…”

“…This function of NFAT5, which can be enhanced by hypertonic stress, supports the classical polarization of macrophages and also protects against Leishmania infection in vivo (Buxadé et al, 2012; Jantsch et al, 2015; Tellechea et al, 2018). While NFAT5 can be inducibly recruited to promoters of target genes, such as Nos2 and Il6 upon TLR activation, it can also be constitutively bound to regulatory regions of other genes in basal conditions as shown for the master MHCII regulatory factor Ciita (Buxadé et al, 2012, 2018). PRR activation induces many types of gene products in addition to prototypical inflammatory cytokines, and receptors such as TLR3 also induce IFN-I expression (Akira et al, 2006; Wu and Chen, 2014).…”