Lymph node stromal cells support the maturation of pre-DCs into cDCs via colony stimulating factor 1
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ABSTRACT: Conventional dendritic cells (cDCs) arise from committed precursor dendritic cells (pre DCs) in the bone marrow that continuously seed the periphery. Pre-DCs and other upstream progenitors proliferate and mature in response to Fms-related receptor tyrosine kinase 3 ligand (FLT3L), which is considered the most important cytokine for cDC development. However, other cytokines such as stem cell factor (SCF) and colony stimulating factor 1 (CSF1) were also shown to induce pre-DC maturation into DC-like cells. It is not completely understood which cells contribute to cDC development once pre-DCs arrive in peripheral tissues. Here, we analyzed the impact of lymph node (LN) fibroblastic stromal cells (FSCs) on the maturation of pre-DCs into cDCs. We could demonstrate that ex vivo isolated LN FSCs co-cultured with pre-DCs induce precursor maturation into DC-like cells, which were capable of efficiently promoting the proliferation of naïve CD4+ T cells. Interestingly, FSCs isolated from mesenteric lymph nodes (mLNs) or peripheral LNs (pLNs) induced DC-like cells with highly comparable transcriptomes, showing similarity to both ex vivo isolated DCs and macrophages based on characteristic signature genes. Finally, by performing supplementation and receptor blocking studies we could demonstrate that CSF1 is a driving factor for LN FSC-mediated pre-DC maturation into DC-like cells. In summary, we could identify CSF1 as a novel stromal cell-derived factor that supports the maturation of pre-DCs into cDCs within secondary lymphoid organs.
Project description:The transcription factors Batf3 and IRF8 are required for development of CD8α+ conventional dendritic cells (cDCs), but the basis for their actions was unclear. Here, we identify two novel Zbtb46+ progenitors that separately generate CD8α+ and CD4+ cDCs and arise directly from the common DC progenitor (CDP). Irf8 expression in the CDP depends on prior PU.1-dependent autoactivation, and specification of pre-CD8 DC progenitors requires IRF8 but not Batf3. However, upon pre-CD8 DC specification, Irf8 autoactivation becomes Batf3-dependent at a CD8α+ cDC-specific enhancer containing multiple AP1-IRF composite elements (AICEs) within the Irf8 superenhancer. CDPs from Batf3-/- mice that specify toward pre-CD8 DCs fail to complete CD8α+ cDC development due to decay of Irf8 autoactivation, and divert to the CD4+ cDC lineage. Examination of histone modifications (H3K27ac and H3K4me1) and 2 transcription factors (Batf3 and Irf8) and the p300 co-factor binding in 3 different dendritic cell subsets
Project description:The transcription factors Batf3 and IRF8 are required for development of CD8α+ conventional dendritic cells (cDCs), but the basis for their actions was unclear. Here, we identify two novel Zbtb46+ progenitors that separately generate CD8α+ and CD4+ cDCs and arise directly from the common DC progenitor (CDP). Irf8 expression in the CDP depends on prior PU.1-dependent autoactivation, and specification of pre-CD8 DC progenitors requires IRF8 but not Batf3. However, upon pre-CD8 DC specification, Irf8 autoactivation becomes Batf3-dependent at a CD8α+ cDC-specific enhancer containing multiple AP1-IRF composite elements (AICEs) within the Irf8 superenhancer. CDPs from Batf3-/- mice that specify toward pre-CD8 DCs fail to complete CD8α+ cDC development due to decay of Irf8 autoactivation, and divert to the CD4+ cDC lineage.
Project description:Committed precursors of conventional dendritic cells (pre-cDCs) derived from the common DC progenitor which differentiate into cDC subpopulations in peripheral tissues have been identified, but committed precursors for plasmacytoid DCs (pDCs) have not been found. Here we show that CDP-derived ‘CCR9- MHCIIlow BST2+ Siglec-H+ pDCs from murine bone marrow which enter the circulation and peripheral tissues have a common DC precursor function in vivo in the steady state. Upon adoptive transfer the fate of CCR9- pDC-like precursors is governed by the tissues they enter. In the bone marrow and liver most transferred CCR9- pDC-like precursors differentiate into CCR9+ pDCs, whereas in peripheral lymphoid organs, lung and intestine they can give rise to CCR9+ pDCs and cDCs. Thus, CCR9- pDC-like cells are novel CDP-derived circulating DC precursors with pDC and cDC potential, whose final differentiation depends on tissue-specific factors allowing adaptation to local requirements. Total RNA obtained from CCR9- pDC-like common DC progenitors and CCR9+ pDCs was compared for differential gene expression. 3 independent isolations were performed for the 2 samples. 6 arrays were run in total.
Project description:Committed precursors of conventional dendritic cells (pre-cDCs) derived from the common DC progenitor which differentiate into cDC subpopulations in peripheral tissues have been identified, but committed precursors for plasmacytoid DCs (pDCs) have not been found. Here we show that CDP-derived ‘CCR9- MHCIIlow BST2+ Siglec-H+ pDCs from murine bone marrow which enter the circulation and peripheral tissues have a common DC precursor function in vivo in the steady state. Upon adoptive transfer the fate of CCR9- pDC-like precursors is governed by the tissues they enter. In the bone marrow and liver most transferred CCR9- pDC-like precursors differentiate into CCR9+ pDCs, whereas in peripheral lymphoid organs, lung and intestine they can give rise to CCR9+ pDCs and cDCs. Thus, CCR9- pDC-like cells are novel CDP-derived circulating DC precursors with pDC and cDC potential, whose final differentiation depends on tissue-specific factors allowing adaptation to local requirements.
Project description:Dendritic cells (DCs) in lymphoid tissue comprise conventional DCs (cDCs) and plasmacytoid DCs (pDCs) that develop from common DC progenitors (CDPs). CDPs are Flt3+c-kitintM-CSFR+ and reside in bone marrow. Here we describe a two-step culture system that recapitulates DC development from c-kithiFlt3-/lo multipotent progenitors (MPPs) into CDPs and further into cDC and pDC subsets. MPPs and CDPs are amplified in vitro with Flt3 ligand, stem cell factor, hyper-IL-6 and insulin- like growth factor-1. The four-factor cocktail readily induces self-renewal of MPPs and their progression into CDPs and has no self-renewal activity on CDPs. The amplified CDPs respond to all known DC poietins and generate all lymphoid tissue DCs in vivo and in vitro. Additionally, in vitro CDPs recapitulate the cell surface marker and gene expression profile of in vivo CDPs and possess a DC-primed transcription profile. Transforming growth factor-β1 (TGF-β1) impacts on CDPs and directs their differentiation towards cDCs. Genome-wide gene expression profiling of TGF-β1-induced genes identified transcription factors, such as interferon regulatory factor-4 (IRF-4) and RelB, that are implicated as instructive factors for cDC subset specification. TGF-β1 also induced the transcription factor inhibitor of differentiation/DNA binding 2 (Id2) that suppresses pDC development. Thus, TGF-β1 directs CDP differentiation into cDC by inducing both cDC instructive factors and pDC inhibitory factors.
Project description:Conventional dendritic cells (cDC) and macrophages form complex networks that are essential for tissue homeostasis and immune defence. While the differentiation and residency of macrophages is regulated within distinct tissue niches, it is unclear whether DC development in tissues follows similar principles given their short life-span. By studying cDC development using fate mapping and depletion/reconstitution approaches, we found that preDC undergo distinct developmental stages. This development that preceded DC maturation was guided within the medullary cords of LNs. Intravital imaging and in situ photoconversion showed that preDC homed via medullary vessels and used them as guiding structures for their migration to the LN parenchyma. Infection-induced relocation of cDCs changed the availability of lymphocyte-derived Flt3l in the medulla which accelerated preDC development to ensure their local replenishment and responsiveness. Uncovering these principles of the spatiotemporal development of cDC and their complex cellular networks may guide novel angles for immunotherapy against cancer.
Project description:Dendritic cells (DCs) in lymphoid tissue comprise conventional DCs (cDCs) and plasmacytoid DCs (pDCs) that develop from common DC progenitors (CDPs). CDPs are Flt3+c-kitintM-CSFR+ and reside in bone marrow. Here we describe a two-step culture system that recapitulates DC development from c-kithiFlt3-/lo multipotent progenitors (MPPs) into CDPs and further into cDC and pDC subsets. MPPs and CDPs are amplified in vitro with Flt3 ligand, stem cell factor, hyper-IL-6 and insulin- like growth factor-1. The four-factor cocktail readily induces self-renewal of MPPs and their progression into CDPs and has no self-renewal activity on CDPs. The amplified CDPs respond to all known DC poietins and generate all lymphoid tissue DCs in vivo and in vitro. Additionally, in vitro CDPs recapitulate the cell surface marker and gene expression profile of in vivo CDPs and possess a DC-primed transcription profile. Transforming growth factor-β1 (TGF-β1) impacts on CDPs and directs their differentiation towards cDCs. Genome-wide gene expression profiling of TGF-β1-induced genes identified transcription factors, such as interferon regulatory factor-4 (IRF-4) and RelB, that are implicated as instructive factors for cDC subset specification. TGF-β1 also induced the transcription factor inhibitor of differentiation/DNA binding 2 (Id2) that suppresses pDC development. Thus, TGF-β1 directs CDP differentiation into cDC by inducing both cDC instructive factors and pDC inhibitory factors. 20 samples in total. Multipotent progenitor - MPP_1 - MPP_2 Common dendritic cell progenitor - CDP_1 - CDP_2 Plasmacytoid dendritic cell - pDC_1 - pDC_2 Conventional dendritic cell - cDC_1 - cDC_2 In vivo common dendritic cell progenitor - In vivo CDP_1 - In vivo CDP_2 Untreated common dendritic cell progenitor (CDP) - CDP_0h_1 - CDP_0h_2 TGF-beta1 treated (4 hours) CDP - CDP_4h_1 - CDP_4h_2 TGF-beta1 treated (8 hours) CDP - CDP_8h_1 - CDP_8h_2 TGF-beta1 treated (12 hours) CDP - CDP_12h_1 - CDP_12h_2 TGF-beta1 treated (24 hours) CDP - CDP_24h_1 - CDP_24h_2
Project description:Dendritic cells (DCs) are specialized sentinel and antigen presenting cells coordinating innate and adaptive immunity. Through proteins on their cell surface, DCs sense changes in the environment, internalize pathogens, present processed antigens, and communicate with other immune cells. By combining chemical labeling and quantitative mass spectrometry, we systematically profiled and compared the cell-surface proteomes of human primary conventional DCs (cDCs) in their resting and activated states. Toll-like receptor activation by a lipopeptide globally reshaped the cell-surface proteome of cDCs, with more than one hundred proteins up or down regulated. By simultaneously elevating positive regulators and reducing inhibitory signals across multiple protein families, the remodeling creates a cell-surface milieu promoting immune responses. Still, cDCs maintain the stimulatory-to-inhibitory balance by leveraging a distinct set of inhibitory molecules. This analysis thus uncovers the molecular complexity and plasticity of the cDC cell surface and provides a roadmap for understanding cDC activation and signaling.
Project description:Classical dendritic cells (cDCs) process and present antigens to T cells. Under steady-state conditions, antigen presentation by cDCs induces tolerance. In contrast, during infection or inflammation, cDCs become activated, express higher levels of cell surface MHC molecules, and induce strong adaptive immune responses. We recently identified a cDC-restricted zinc finger transcription factor, zDC, that is not expressed by other immune cell populations, including pDCs, monocytes, or macrophages. Here we define the zDC consensus DNA binding motif and the genes regulated by zDC using chromatin immunoprecipitation and deep sequencing. By deleting zDC from the mouse genome, we show that zDC is primarily a negative regulator of cDC gene expression. zDC deficiency alters the cDC subset composition in the spleen in favor of CD8+ DCs, upregulates activation pathways in steady state cDCs including elevated MHC II expression, and enhances cDC production of VEGF leading to increased vascularization of skin-draining lymph nodes. Consistent with these observations, zDC protein expression is rapidly downregulated after TLR ligation. Thus, zDC is a TLR-responsive cDC-specific transcriptional repressor that is in part responsible for preventing cDC maturation in the steady state. Splenic classical dendritic cells from mice lacking the second exon of the zDC gene were sorted. DEC-205+ and DCIR2+ cDCs from the zDC knockout mice were collected for comparison with wildtype cDCs. Three replicates per group. The wildtype samples have been previously analyzed and are available in the GEO database in Series GSE6259. The complete dataset representing: (1) the zDC knockout Samples and (2) the wildtype Samples from Series GSE6259 (re-processed using RMA), is linked below as a supplementary file.
Project description:Developmental origins of dendritic cells (DCs) including conventional DCs (cDCs, comprising cDC1 and cDC2 subsets) and plasmacytoid DCs (pDCs) remain unclear. We studied DC development in unmanipulated adult mice using inducible lineage tracing combined with clonal DNA "barcoding" and single-cell transcriptome and phenotype analysis (CITE-Seq). Inducible tracing of Cx3cr1+ hematopoietic progenitors in the bone marrow showed that they simultaneously produce all DC subsets including pDCs, cDC1s and cDC2s. Clonal tracing of hematopoietic stem cells (HSCs) and of Cx3cr1+ progenitors revealed clone sharing between cDC1s and pDCs, but not between the two cDC subsets or between pDCs and B cells. Accordingly, CITE-Seq analyses of differentiating HSCs and Cx3cr1+ progenitors identified progressive stages of pDC development including Cx3cr1+ Ly-6D+ propDCs that were distinct from lymphoid progenitors. These results reveal the shared origin of pDCs and cDCs, and suggest a revised scheme of DC development whereby pDCs share clonal relationship with cDC1s