Project description:During inflammation, monocytes differentiate within tissues into macrophages (mo-Mac) or dendritic cells (mo-DC). Whether these two progenies derive from alternative differentiation pathways or represent different stages along a continuum remains unclear. Here we addressed this question using temporal single-cell RNA sequencing in an in vitro model allowing the simultaneous differentiation of human mo-Mac and mo-DC. We evidenced divergent differentiation paths, with a fate decision occurring within the first 24 hours. We confirmed this result in vivo using a mouse model of peritonitis. Using a computational approach, we identified candidate transcription factors potentially involved in monocyte fate commitment. We demonstrated that IRF1 is necessary for mo-Mac differentiation, independently of its transcriptional control of interferon-stimulated genes. In addition, we validated the transcription factors ZNF366 and MAFF as regulators of mo-DC development. Our results indicate that mo-Mac and mo-DC represent two alternative cell fates requiring distinct transcription factors for their differentiation.
Project description:Comparison of the DNA methylation profiles of CD14+ monocytes from human peripheral blood with derived dendritic cells (DCs) and macrophages (MACs) obtained by exposure with GM-CSF/IL-4 and GM-CSF, respectively. Effects on the methylation profiles of DCs and MACs of JAK3 inhibitor PF-956980 The methylation profiles of bisulfite-modified DNA of human CD14+ monocytes were compared with derived dendritic cells (DCs), macrophages (MACs) following GM-CSF/IL-4 and GM-CSF incubation, and DC and MAC samples incubated with JAK3 inhibitor PF-956980 using the Infinium HumanMethylation450 BeadChips (Illumina, Inc., San Diego, CA,). This platform allows the interrogation of >485,000 methylation sites per sample at single-nucleotide resolution, and comprises an average of 17 CpG sites per gene in the 99% of RefSeq genes. 96% of CpG islands are covered, with additional coverage in CpG island shores and the regions flanking them. The samples were hybridized in the array following the manufacturerâÂÂs instructions. Total DNA isolated by standard procedures from CD14+ cells (total monocytes, MOs) corresponding to three sets of samples of monocytes (MOs), derived DCs and MACs (DCs and iMACs; DMSO as these samples were differentiated in the absence of JAK3 inhibitors) and DCs and MACs differentiated in the presence of JAK3 inhibitor PF-956980.
Project description:Comparison of the DNA methylation profiles of CD14+ monocytes from human peripheral blood with derived dendritic cells (DCs) and macrophages (MACs) obtained by exposure with GM-CSF/IL-4 and GM-CSF, respectively. Effects on the methylation profiles of DCs and MACs of JAK3 inhibitor PF-956980 The methylation profiles of bisulfite-modified DNA of human CD14+ monocytes were compared with derived dendritic cells (DCs), macrophages (MACs) following GM-CSF/IL-4 and GM-CSF incubation, and DC and MAC samples incubated with JAK3 inhibitor PF-956980 using the Infinium HumanMethylation450 BeadChips (Illumina, Inc., San Diego, CA,). This platform allows the interrogation of >485,000 methylation sites per sample at single-nucleotide resolution, and comprises an average of 17 CpG sites per gene in the 99% of RefSeq genes. 96% of CpG islands are covered, with additional coverage in CpG island shores and the regions flanking them. The samples were hybridized in the array following the manufacturer’s instructions.
Project description:The differentiation of human blood monocytes (MO), the post-mitotic precursors of macrophages (MAC) and dendritic cells (moDC), is accompanied by the active turnover of DNA methylation, but the extent, consequences and mechanisms of DNA methylation changes remain unclear. Here we profile and compare epigenetic landscapes during IL-4/GM-CSF-driven MO differentiation across the genome and detect several thousand regions that are actively demethylated during culture, both with or without accompanying changes in chromatin accessibility or transcription factor (TF) binding. We further identify TF that are globally associated with DNA demethylation processes. While interferon regulatory factor 4 (IRF4) is found to control hallmark DC functions with less impact on DNA methylation, early growth response 2 (EGR2), proves essential for MO differentiation as well as DNA methylation turnover at its binding sites. EGR2 is shown to interact with the 5mC hydroxylase TET2 and its consensus sequences show a characteristic DNA methylation footprint at demethylated sites with or without detectable protein binding. Our findings reveal a novel and essential role for EGR2 as epigenetic pioneer in human MO and suggest that active DNA demethylation can be initiated by TET2 recruiting TF both at stable and transient binding sites.
Project description:DC-SIGN+ monocyte-derived dendritic cells (mo-DCs) play important roles in bacterial infections and inflammatory diseases, but the factors regulating their differentiation and proinflammatory status remain poorly defined. Here, we identify a micro-RNA, miR-181a, and a molecular mechanism that simultaneously regulate the acquisition of DC-SIGN+ expression and the activation state of DC-SIGN+ mo-DCs. Specifically, we show that miR-181a promotes DC-SIGN expression during terminal mo-DC differentiation and limits its sensitivity and responsiveness to TLR triggering and CD40 ligation. Mechanistically, miR-181a sustains ERK-MAPK signaling in mo-DCs, thereby enabling the maintenance of high levels of DC-SIGN and a high activation threshold. Low miR-181a levels during mo-DC differentiation, induced by inflammatory signals, do not support the high phospho-ERK signal transduction required for DC-SIGNhi mo-DCs and lead to development of proinflammatory DC-SIGNlo/- mo-DCs. Collectively, our study demonstrates that high DC-SIGN expression levels and a high activation threshold in mo-DCs are linked and simultaneously maintained by miR-181a.
Project description:The molecular requirements that guide the differentiation of monocytes into macrophages or monocyte-derived dendritic cells (Mo-DCs) are poorly understood. Here, we demonstrate that the nuclear orphan receptor NR4A3 guides monocyte fate and is essential for Mo-DC differentiation. Nr4a3-/- mice are impaired in the in vivo generation of DC-SIGN+ Mo-DCs following LPS stimulation and, as such, are defective at priming a CD8+ T cell response to gram negative bacteria. We also demonstrate that NR4A3 is an essential downstream effector of IRF4 during in vitro differentiation of Mo-DCs with GM-CSF and IL-4 and that, in absence of NR4A3, monocytes are diverted to macrophages. Our transcriptomic analysis of the genes regulated by NR4A3 reveals that the acquisition of the Mo-DC differentiation program is intertwined with the acquisition of a migratory signature. Furthermore, NR4A3 is critical for steady-state migration of non-lymphoid tissue conventional DCs to lymph nodes. Altogether, our results highlight a unique role for NR4A3 in Mo-DC differentiation and in the acquisition of migratory properties.
Project description:Peripheral blood monocytes are the starting material utilized in conventional dendritic cell (DC) vaccination for the treatment of a broad range of malignancies. While the use of cytokines and growth factors to polarize monocyte-derived DC to distinct phenotypes is well-established, little is known about the contributions of distinct human monocyte subsets to monocyte-derived DC function and patient responses to vaccination. To investigate the status of monocyte subsets in cancer patients and following culture into DC, we isolated classical (C-Mo), intermediate (I-Mo), and non-classical (NC-Mo) from the peripheral blood of renal cell carcinoma (RCC) patients prior to DC vaccination (NCT00085436) and from anonymous healthy donors. Patients treated with DC vaccination who were long term survivors (>100 months survival) had a unique monocyte signature with a two-fold higher percentage of NC-Mo in pretreatment peripheral blood compared to other RCC patients. RCC patient monocytes from each subset were transcriptionally distinct from healthy donor monocytes. Further transcriptional analysis determined that each monocyte subset was characterized by a discrete gene expression profile before and after DC maturation. Phenotypic analysis showed that DC derived from NC-Mo expressed higher levels of CD80, CD83, CD86, HLA-DR, and CD40 compared to DC originating from C-Mo and secreted increased amounts of IL-12p70 following CD40L stimulation. Collectively, these findings establish that DC derived from NC-Mo are potent antigen presenting cells and provide the foundation for future vaccination strategies that enrich NC-Mo prior to DC maturation.
Project description:Peripheral blood monocytes are the starting material utilized in conventional dendritic cell (DC) vaccination for the treatment of a broad range of malignancies. While the use of cytokines and growth factors to polarize monocyte-derived DC to distinct phenotypes is well-established, little is known about the contributions of distinct human monocyte subsets to monocyte-derived DC function and patient responses to vaccination. To investigate the status of monocyte subsets in cancer patients and following culture into DC, we isolated classical (C-Mo), intermediate (I-Mo), and non-classical (NC-Mo) from the peripheral blood of renal cell carcinoma (RCC) patients prior to DC vaccination (NCT00085436) and from anonymous healthy donors. Patients treated with DC vaccination who were long term survivors (>100 months survival) had a unique monocyte signature with a two-fold higher percentage of NC-Mo in pretreatment peripheral blood compared to other RCC patients. RCC patient monocytes from each subset were transcriptionally distinct from healthy donor monocytes. Further transcriptional analysis determined that each monocyte subset was characterized by a discrete gene expression profile before and after DC maturation. Phenotypic analysis showed that DC derived from NC-Mo expressed higher levels of CD80, CD83, CD86, HLA-DR, and CD40 compared to DC originating from C-Mo and secreted increased amounts of IL-12p70 following CD40L stimulation. Collectively, these findings establish that DC derived from NC-Mo are potent antigen presenting cells and provide the foundation for future vaccination strategies that enrich NC-Mo prior to DC maturation.
Project description:Peripheral blood monocytes are the starting material utilized in conventional dendritic cell (DC) vaccination for the treatment of a broad range of malignancies. While the use of cytokines and growth factors to polarize monocyte-derived DC to distinct phenotypes is well-established, little is known about the contributions of distinct human monocyte subsets to monocyte-derived DC function and patient responses to vaccination. To investigate the status of monocyte subsets in cancer patients and following culture into DC, we isolated classical (C-Mo), intermediate (I-Mo), and non-classical (NC-Mo) from the peripheral blood of renal cell carcinoma (RCC) patients prior to DC vaccination (NCT00085436) and from anonymous healthy donors. Patients treated with DC vaccination who were long term survivors (>100 months survival) had a unique monocyte signature with a two-fold higher percentage of NC-Mo in pretreatment peripheral blood compared to other RCC patients. RCC patient monocytes from each subset were transcriptionally distinct from healthy donor monocytes. Further transcriptional analysis determined that each monocyte subset was characterized by a discrete gene expression profile before and after DC maturation. Phenotypic analysis showed that DC derived from NC-Mo expressed higher levels of CD80, CD83, CD86, HLA-DR, and CD40 compared to DC originating from C-Mo and secreted increased amounts of IL-12p70 following CD40L stimulation. Collectively, these findings establish that DC derived from NC-Mo are potent antigen presenting cells and provide the foundation for future vaccination strategies that enrich NC-Mo prior to DC maturation.