Ablation of cDC2 development by triple mutations within the Zeb2 enhancer.

The divergence of the common dendritic cell progenitor1-3 (CDP) into the conventional type 1 and type 2 dendritic cell (cDC1 and cDC2, respectively) lineages4,5 is poorly understood. Some transcription factors act in the commitment of already specified progenitors-such as BATF3, which stabilizes Irf8 autoactivation at the +32 kb Irf8 enhancer4,6-but the mechanisms controlling the initial divergence of CDPs remain unknown. Here we report the transcriptional basis of CDP divergence and describe the first requirements for pre-cDC2 specification. Genetic epistasis analysis7 suggested that Nfil3 acts upstream of Id2, Batf3 and Zeb2 in cDC1 development but did not reveal its mechanism or targets. Analysis of newly generated NFIL3 reporter mice showed extremely transient NFIL3 expression during cDC1 specification. CUT&RUN and chromatin immunoprecipitation followed by sequencing identified endogenous NFIL3 binding in the -165 kb Zeb2 enhancer8 at three sites that also bind the CCAAT-enhancer-binding proteins C/EBPα and C/EBPβ. In vivo mutational analysis using CRISPR-Cas9 targeting showed that these NFIL3-C/EBP sites are functionally redundant, with C/EBPs supporting and NFIL3 repressing Zeb2 expression at these sites. A triple mutation of all three NFIL3-C/EBP sites ablated Zeb2 expression in myeloid, but not lymphoid progenitors, causing the complete loss of pre-cDC2 specification and mature cDC2 development in vivo. These mice did not generate T helper 2 (TH2) cell responses against Heligmosomoides polygyrus infection, consistent with cDC2 supporting TH2 responses to helminths9-11. Thus, CDP divergence into cDC1 or cDC2 is controlled by competition between NFIL3 and C/EBPs at the -165 kb Zeb2 enhancer.

Liu TT ，Kim S ，Desai P ，Kim DH ，Huang X ，Ferris ST ，Wu R ，Ou F ，Egawa T ，Van Dyken SJ ，Diamond MS ，Johnson PF ，Kubo M ，Murphy TL ，Murphy KM ... -  《-》

An Nfil3-Zeb2-Id2 pathway imposes Irf8 enhancer switching during cDC1 development.

Bagadia P ，Huang X ，Liu TT ，Durai V ，Grajales-Reyes GE ，Nitschké M ，Modrusan Z ，Granja JM ，Satpathy AT ，Briseño CG ，Gargaro M ，Iwata A ，Kim S ，Chang HY ，Shaw AS ，Murphy TL ，Murphy KM ... -  《-》

Anatomy of a superenhancer.

Kim S ，Liu TT ，Ou F ，Murphy TL ，Murphy KM ... -  《-》

Cryptic activation of an Irf8 enhancer governs cDC1 fate specification.

Durai V ，Bagadia P ，Granja JM ，Satpathy AT ，Kulkarni DH ，Davidson JT 4th ，Wu R ，Patel SJ ，Iwata A ，Liu TT ，Huang X ，Briseño CG ，Grajales-Reyes GE ，Wöhner M ，Tagoh H ，Kee BL ，Newberry RD ，Busslinger M ，Chang HY ，Murphy TL ，Murphy KM ... -  《-》

IL-6 selectively suppresses cDC1 specification via C/EBPβ.

Cytokines produced in association with tumors can impair antitumor immune responses by reducing the abundance of type 1 conventional dendritic cells (cDC1), but the mechanism remains unclear. Here, we show that tumor-derived IL-6 generally reduces cDC development but selectively impairs cDC1 development in both murine and human systems through the induction of C/EBPβ in the common dendritic cell progenitor (CDP). C/EBPβ and NFIL3 compete for binding to sites in the Zeb2 -165 kb enhancer and support or repress Zeb2 expression, respectively. At homeostasis, pre-cDC1 specification occurs upon Nfil3 induction and consequent Zeb2 suppression. However, IL-6 strongly induces C/EBPβ expression in CDPs. Importantly, the ability of IL-6 to impair cDC development is dependent on the presence of C/EBPβ binding sites in the Zeb2 -165 kb enhancer, as this effect is lost in Δ1+2+3 mutant mice in which these binding sites are mutated. These results explain how tumor-associated IL-6 suppresses cDC1 development and suggest therapeutic approaches preventing abnormal C/EBPβ induction in CDPs may help reestablish cDC1 development to enhance antitumor immunity.

Kim S ，Chen J ，Jo S ，Ou F ，Ferris ST ，Liu TT ，Ohara RA ，Anderson DA ，Wu R ，Chen MY ，Gillanders WE ，Gillanders WE ，Murphy TL ，Murphy KM ... -  《-》