Project description:Abstract Two major dendritic cell (DC) subsets have been described in the islets of mice: The immunogenic CD8α-CD11b+ DCs and the tolerogenic CD8α+CD103+ DCs. We have recently reported on reduced numbers of the minor population of tolerogenic CD8α+CD103+ DCs in the pancreas of 5 week old pre-diabetic non-obese diabetic (NOD) mice. Aim: To analyze also the larger subset of CD11c+CD8α- DCs isolated from the pancreas of pre-diabetic NOD mice 1) for maturation and tolerance inducing molecules found abnormally expressed on CD8α+CD103+ DCs, and 2) for genome-wide gene expression to further elucidate abnormalities in underlying gene expression networks. Methods: CD11c+CD8α- DCs were isolated from 5 week old C57BL/6 and NOD pancreas. Expression of cell surface markers including CD86, CCR5, CD11b, CD103, Clec9a, CD24 and CD200R3 were measured by FACS. Genome-wide gene expression by microarray was assessed during the steady state and after in vitro LPS stimulation. Results: The steady state pancreatic CD11c+ CD8α- DCs during the pre-diabetic stage showed: 1) A reduced expression of several gene networks important for the prime functions of the cell, such as for cell renewal, immune stimulation and immune tolerance induction, for migration and for the provision of growth factors for beta cell regeneration. This general deficiency state was corroborated by a reduced in vivo proliferation (BrdU incorporation) of the cells and the reduced expression in FACS analysis of CD86, CCR5, CD103, Clec9a, CD24 and CD200R3 on the cells. 2) A hyper reactivity of these cells to LPS correlated with an enhanced pro-inflammatory state characterized by altered expression of a number of classical pro-inflammatory factors and cytokines. Conclusion: The NOD CD11c+CD8α- DCs seem to be Janus-faced depending on the conditions: Deficient in steady state with reduced immune stimulation capabilities also for tolerance induction; over-inflammatory with a molecular profile suggesting a preferential stimulatory capacity for Th1 cells when encountering a Pathogen-Associated Molecular Pattern (PAMP) in the form of LPS. We used microarray gene expression analysis to explain the abnormal expression of several cell surface markers involved in tolerace, migration and maturation in the steady-state and to measure the effect of a PAMP such as LPS We isolated RNA from FACS sorted CD11c+CD8α- DCs in 10 pooled pancreases from pre-diabetic NOD and non-diabetic C57BL/6 mice at 5 weeks. In addition, we treated in another experiment the isolated pancreas DCs with LPS (and PBS), incubated for 18h and measured gene expression. We compared gene expression between strains NOD vs C57BL/6 under steady-state and after in-vitro LPS/PBS stimulation.
Project description:Expression data from NOD and C57BL/6 mouse pancreas CD8α- Dendritic Cells (DCs) under steady-state and after in-vitro LPS stimulation
Project description:Abstract Two major dendritic cell (DC) subsets have been described in the islets of mice: The immunogenic CD8α-CD11b+ DCs and the tolerogenic CD8α+CD103+ DCs. We have recently reported on reduced numbers of the minor population of tolerogenic CD8α+CD103+ DCs in the pancreas of 5 week old pre-diabetic non-obese diabetic (NOD) mice. Aim: To analyze also the larger subset of CD11c+CD8α- DCs isolated from the pancreas of pre-diabetic NOD mice 1) for maturation and tolerance inducing molecules found abnormally expressed on CD8α+CD103+ DCs, and 2) for genome-wide gene expression to further elucidate abnormalities in underlying gene expression networks. Methods: CD11c+CD8α- DCs were isolated from 5 week old C57BL/6 and NOD pancreas. Expression of cell surface markers including CD86, CCR5, CD11b, CD103, Clec9a, CD24 and CD200R3 were measured by FACS. Genome-wide gene expression by microarray was assessed during the steady state and after in vitro LPS stimulation. Results: The steady state pancreatic CD11c+ CD8α- DCs during the pre-diabetic stage showed: 1) A reduced expression of several gene networks important for the prime functions of the cell, such as for cell renewal, immune stimulation and immune tolerance induction, for migration and for the provision of growth factors for beta cell regeneration. This general deficiency state was corroborated by a reduced in vivo proliferation (BrdU incorporation) of the cells and the reduced expression in FACS analysis of CD86, CCR5, CD103, Clec9a, CD24 and CD200R3 on the cells. 2) A hyper reactivity of these cells to LPS correlated with an enhanced pro-inflammatory state characterized by altered expression of a number of classical pro-inflammatory factors and cytokines. Conclusion: The NOD CD11c+CD8α- DCs seem to be Janus-faced depending on the conditions: Deficient in steady state with reduced immune stimulation capabilities also for tolerance induction; over-inflammatory with a molecular profile suggesting a preferential stimulatory capacity for Th1 cells when encountering a Pathogen-Associated Molecular Pattern (PAMP) in the form of LPS. We used microarray gene expression analysis to explain the abnormal expression of several cell surface markers involved in tolerace, migration and maturation in the steady-state and to measure the effect of a PAMP such as LPS
Project description:Functional characterization of human dendritic cell subsets is limited due to the very low frequency of these cells in vivo. We developed an in vitro culture system for the simultaneous generation of XCR1+ DCs and MoDCs from cord blood CD34+ cells. Their global gene expression profiles at steady state and under activation, phenotypes, morphologies and responses to different TLR ligands where characterized and compared with those of their in vivo counterparts. The study demonstrated that the XCR1+ DCs generated in vitro from cord blood CD34+ cells are equivalent to blood XCR1+ DCs and also allowed a rigorous comparison of this DC subset with MoDC which are often considered as the reference model for DCs. Altogether, our results showed that in vitro generated XCR1+ DCs are a better model for the study of blood DC than the conventionally used MoDCs. The different dendritic cell subsets used for the study were either generated in vitro from cord blood CD34+ cells with recombinant human cytokines or isolated from peripheral blood. The subsets were purified by fluorescence-activated cell sorting and their responses to PolyI:C, LPS or R848 were studied including by gene expression profiling.
Project description:T helper type 2 (Th2) responses are induced by protease allergens and helminthes. However the molecular mechanisms that initiate Th2 responses are poorly understood. To obtain insight into this mechanism, we performed a microarray analysis of lymph node DCs stimulated in vitro with the protease allergen papain, or with LPS, a Th1 inducing stimulus. Key words: Th2 response, LPS, dendritic cells, Papain CD11c+ DCs were isolated from the lymph nodes of C57BL/6 mice, and cultured in vitro (1x106 DCs per ml) with 500 3T3-CD40L fibroblasts, either alone, or in the presence of papain (25 µg/ml) or LPS (1 µg/ml). 4h and 17h later, the cells were harvested and RNA isolated and processed for microarray analyses. RNA was extracted and processed from freshly isolated LN DCs. For a given time point, the expression profile of DCs treated with papain or LPS, were compared to that of untreated DCs
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:Homeostatic control of dendritic cell (DC) survival is crucial for a productive adaptive immune response, but the molecular mechanism is not well defined. Moreover, how DCs influence homeostasis of the immune system under steady state remains unclear. Combining DC-specific and inducible deletion systems, we report here that the kinase TAK1 is an essential regulator of DC survival and immune system homeostasis and function. Deficiency of TAK1 in CD11c+ cells diminished DC populations, especially the CD8+ and CD103+ DC subsets in the lymphoid and non-lymphoid organs, respectively. This was associated with increased apoptosis of DCs, whereas DC proliferation and differentiation from precursors appeared largely normal. In addition, acute deletion of TAK1 caused DC apoptosis, indicating a direct role of TAK1 in actively maintaining DC survival. TAK1 deficiency impaired activities of the pro-survival NF-kB and AKT pathways but upregulated expression of the pro-apoptotic molecule Bim. Under steady state, loss of TAK1 in DCs resulted in a myeloid proliferative disorder, and altered homeostasis of T cells. In response to antigen stimulation, TAK1-deficient DCs were impaired for T cell priming and regulatory T cell generation. Therefore, TAK1 orchestrates a pro-survival checkpoint in DCs that affects the homeostasis and function of the immune system RNA extracted from three replicate samples of wild-type and Map3k7 (TAK1) knockout dendritic cells was analyzed on Affymetrix gene expression arrays
Project description:DCs are critical for regulating immune responses. miRNAs are small, noncoding RNAs and play a significant role in regulating immune responses. miR-142 is a hematopoietic specific miRNA. To explore the role of miR-142 in regulating DCs’ immune responses, we generated mutant mice bearing a targeted deletion of the miR-142 gene. We used microarrays to detail the global program of gene expression underlying the profile changes between miR-142 KO and WT DCs and identified distinct classes of up-regulated or down-regulated genes in steady state or LPS stimulation during this process.
Project description:Type I Interferons encompasses a large family of closely related cytokines comprising of at least 13 IFN-α isotypes and single IFN-β. Both IFN-α and IFN-β exert their activity through a common receptor IFNAR. Type I Interferons have broad regulatory effects and various subtypes of dendritic cells are influenced by this cytokines. In our study we asked question whether the low, constitutive levels of type I Interferons produced under steady state conditions are important for proper function of splenic conventional dendritic cells. In this approach we sorted out two populations (CD8α+ and CD8α-) of splenic dendritic cells (DCs) from untreated WT, IFN-β-/- and IFNAR-/- C57Bl/6 mice. All mice were between 8-10 weeks old. Further we isolated RNA and performed microarray analysis. Each DCs population was repeated twice.
Project description:Purpose:The purpose of this study is to detect activated or silenced genes during LPS-induced dendritic cell. Gene expression differences between two samples could be found using transcriptome profiling (RNA-seq) analysis. Methods:Mouse dendritic cells were generated from bone marrow cells in RPMI-1640 medium with recombinant mouse GM-CSF and IL-4, immature DCs were obtained before or after LPS stimulation. Immature DCs were sorted respectively based on marker CD86 and Iab(MHCII) using flowcytrometer. DC mRNA profiles were generated by deep sequencing,using Illumina. Results: We mapped about 10 million sequence reads per sample to the mouse genome, identified hundreds of genes with significant mRNA variation during LPS stimulation. DC mRNA profiles immature BMDCs were generated by deep sequencing