Project description:Analysis of the p38 MAPK pathway in regulation of dendritic cells (DCs) differentiation at the gene expression level. Bone marrow cells were cultured with mGM-CSF (20 ng/ml) in the presence of 1.5 mM of SB202190 or 0.1% DMSO. At day 7, semi-adherent cells were collected as immature DCs (iDCs). iDCs were matured by TNF-a (10 ng/ml) and IL-1b (10 ng/ml) for 48 hours. Results showed that p38 MAPK activity in DC progenitor cells acts as an antigen presentation attenuator, and disabling this critical brake during DC differentiation endows DCs with enhanced immunogenicity, which may be useful for the induction of antitumor immune responses. Total RNA was obtained from 2-day-cultured bone marrow cells, iDCs and mature DCs.
Project description:Analysis of the p38 MAPK pathway in regulation of dendritic cells (DCs) differentiation at the gene expression level. Bone marrow cells were cultured with mGM-CSF (20 ng/ml) in the presence of 1.5 mM of SB202190 or 0.1% DMSO. At day 7, semi-adherent cells were collected as immature DCs (iDCs). iDCs were matured by TNF-a (10 ng/ml) and IL-1b (10 ng/ml) for 48 hours. Results showed that p38 MAPK activity in DC progenitor cells acts as an antigen presentation attenuator, and disabling this critical brake during DC differentiation endows DCs with enhanced immunogenicity, which may be useful for the induction of antitumor immune responses.
Project description:Dendritic cells (DCs) uniquely direct the adaptive immune response towards activation or inhibition, yet little is known how these opposite programs are regulated at the transcriptional level. Here we applied genome-wide approaches to delineate the molecular function of DC-Specific transCRIPT (DC-SCRIPT/ZNF366), an 11 Zn finger-containing transcription factor potentiating DC-function by limiting IL-10 production. Transcriptome analysis identified DC-SCRIPT to affect expression of genes involved in MAPK signaling, and ChIP-Seq analysis showed binding of DC-SCRIPT to GA-rich enhancers nearby genes encoding MAPK Dual-Specificity Phosphatases (DUSPs). Functional studies demonstrated that DC-SCRIPT-knockdown DCs express much less DUSP4 and exhibit increased phosphorylation of all the three major MAPKs (ERK, JNK and p38). Enhanced ERK signaling in DC-SCRIPT-knockdown DCs led to higher production of the immune-inhibitory cytokine IL-10, which could be reverted by DUSP4 overexpression. These results delineate the molecular mechanism DC-SCRIPT employs to limit IL-10 production in DCs, thereby fine-tuning these professional antigen-presenting cells towards immune activation.
Project description:In chorioamnionitis (CAM), a major cause of preterm birth (PTB), maternal-fetal inflammatory responses in the decidua and amnio-chorion cause the release of cytokines that elicit cervical ripening, fetal membrane rupture and myometrial activation. We posited that this inflammatory milieu can trigger PTB via inhibited progesterone receptor (PR) expression and increased decidual prostaglandin (PG) production. We found significantly lower decidual cell PR levels in CAM-complicated PTB using immunohistochemistry. Decidual cells (DCs) treated with IL-1β displayed decreased PR expression and significantly increased PGE2 and PGF2α production and COX2 expression. While addition of PGF2α to DC cultures was also found to suppress PR expression, the COX inhibitor, indomethacin, did not reverse IL-1β suppression of PR expression in DC cultures. Although IL-1β treatment activated NF-B, ERK1/2 and p38 MAPK signaling cascades in DCs, only inhibition of ERK1/2 MAPK signaling completely reversed IL-1β suppressed PR levels. These findings suggest that CAM-associated PTB is induced at least in part by IL-1β-mediated functional progesterone withdrawal.
Project description:Transcriptome analysis of IFNγ-insensitive DCs IFNγ signaling drives dendritic cells (DCs) to promote type I T cell (Th1) immunity. Here, we show that activation of DCs by IFNγ is equally crucial for the differentiation of a population of T-bet+ regulatory T (Treg) cells specialized to inhibit Th1 immune responses. Conditional deletion of IFNγ receptor in DCs but not in Treg cells resulted in a severe defect in this specific Treg cell subset, leading to exacerbated immune pathology during parasitic infections. Mechanistically, IFNγ-unresponsive DCs failed to produce sufficient amount of IL-27, a cytokine required for optimal T-bet induction in Treg cells. Thus, IFNγ signalling endows DCs with the ability to efficiently control a specific type of T cell immunity through promoting a corresponding Treg cell population. We analyzed saliva from 3 WT DC samples and 3 IFNγR2 KO DC samples isolated from unmanipulated mice. In addition, we analyzed saliva from 3 WT DC samples and 3 IFNγR2 KO DC samples isolated from mixed BM chimeras (WT + IFNgR2KO) day 8 T. gondii infected.
Project description:Analysis of the specific transcriptional changes on DCs provided by direct pattern recogition receptor (PRR) or IFNAR signaling that are required for DC maturation after poly IC stimulation. Results provide important information about the intricate differentiation process of DC maturation and the importance of type I IFNs for DC immunogenicity. WT/IFNA-/- or WT/PRR-/- mixed-chimera mice were injected with 50 ug Poly-IC i.p. in vivo 4 and 14 hr later, wild type and KO CD11chi CD3- DX5- B220- DCs were FACS sorted based on CD45.2 expression. Total RNA was isolated and expression profile was compared between unstimulated and activated WT and KO DCs.
Project description:Expression data from dendritic cell subsets derived or sorted from control littermate and CD11c-Cre/BRAFV600E(flox-CA) mice Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasia characterized by granulomatous lesions containing pathological CD207+ dendritic cells (DCs) with constitutively activated mitogen-activated protein kinase (MAPK) pathway signaling. Approximately 60% of LCH patients harbor somatic BRAFV600E mutations localizing to CD207+ DCs within lesions. However, the mechanisms driving BRAFV600E+ LCH cell accumulation in lesions remain unknown. Here we show that sustained extracellular signal–related kinase activity induced by BRAFV600E inhibits C-C motif chemokine receptor 7 (CCR7)–mediated DC migration, trapping DCs in tissue lesions. Additionally, BRAFV600E increases expression of BCL2-like protein 1 (BCL2L1) in DCs, resulting in resistance to apoptosis. Pharmacological MAPK inhibition restores migration and apoptosis potential in a mouse LCH model, as well as in primary human LCH cells. We also demonstrate that MEK inhibitor-loaded nanoparticles have the capacity to concentrate drug delivery to phagocytic cells, significantly reducing off-target toxicity. Collectively, our results indicate that MAPK tightly suppresses DC migration and augments DC survival, rendering DCs in LCH lesions trapped and resistant to cell death.
Project description:Vaccine development involves time-consuming and expensive evaluation of candidate vaccines in animal models. As mediators of both innate and adaptive immune responses dendritic cells (DCs) are considered to be highly important for vaccine performance. Here we evaluated in how far the response of DCs to a vaccine in vitro is in line with the immune response the vaccine evokes in vivo. To this end, we investigated the response of murine bone marrow-derived DCs to whole inactivated virus (WIV) and subunit (SU) influenza vaccine preparations. These vaccine preparations were chosen because they differ in the immune response they evoke in mice with WIV being superior to SU vaccine through induction of higher virus-neutralizing antibody titers and a more favorable Th1-skewed response phenotype. To evaluate if in vivo immunogenicity is reflected by DC reactions in vitro we studied the gene expression signature of murine bone-marrow-derived conventional DCs (cDCs) upon stimulation with WIV or SU influenza vaccine or, for reasons of comparison, with live influenza virus. Dendritic cells stimulated with PBS served as a control. Gene expression analysis was performed on samples 4, 12 and 24 hours after the start of stimulation.
Project description:Analysis of the specific transcriptional changes on DCs provided by direct pattern recogition receptor (PRR) or IFNAR signaling that are required for DC maturation after poly IC stimulation. Results provide important information about the intricate differentiation process of DC maturation and the importance of type I IFNs for DC immunogenicity.
Project description:In mice, two restricted DC progenitors, macrophage-dendritic progenitor (MDP) and common dendritic cell progenitor (CDP) demonstrate increasing commitment of DC lineage as they sequentially lose granulocyte and monocyte potential respectively. Identifying these progenitors has enabled understanding of the role of DCs and monocytes in immunity and tolerance in mice. In humans, however, restricted monocyte and DC progenitors remain unknown. Progress in studying human DC development has been hampered by lack of an in vitro culture system that recapitulates in vivo DC hematopoiesis. Here we report a culture system that supports development of CD34+ hematopoietic stem cell progenitors into the three major human DC subsets, monocytes, granulocytes, NK and B cells. Using this culture system we defined the pathway for human DC development, and revealed the sequential origin of human DCs from increasingly restricted progenitors: a granulocyte-monocyte-DC progenitor (hGMDP) that develops into a monocyte-DC progenitor (hMDP) that develops into monocytes and a common DC progenitor (hCDP) that is restricted to produce the three major DC subsets. The phenotype of the DC progenitors partially overlaps with granulocyte monocyte progenitors (GMPs). These progenitors reside in human cord blood and bone marrow but not in the blood or lymphoid tissues in the steady state. We performed whole transcriptome expression analysis on monocytes and subsets of dendritic cells i.e. CD1c+ DCs, CD141+ DCs and CD303+ pDCs isolated from blood or differentiated in culture from cord blood CD34+ cells in presence of MS5 stromal cells and Flt3l, GM-CSF and SCF cytokines.