ABSTRACT: Analysis of gene expressions in mouse splenic dendritic cells (DCs). DCs were purified into two subsets, CD8-positive and -negative ones. DCs were expanded in vivo by injecting Flt3L-producing tumors into the backs of C57BL/6 mice. Overall design: To expand DCs in vivo, Flt3L-producing B16 melanoma cells were injected to the backs of mice. Then, 10-12 days later, splenic DCs were enriched by MACS and purified into CD3-B220-CD8a+CD11c+ and CD3-B220-CD8a-CD11c+ cells by FACS cell sorter.
Project description:Analysis of gene expressions in mouse splenic dendritic cells (DCs). DCs were purified into two subsets, CD8-positive and -negative ones. DCs were expanded in vivo by injecting Flt3L-producing tumors into the backs of C57BL/6 mice. To expand DCs in vivo, Flt3L-producing B16 melanoma cells were injected to the backs of mice. Then, 10-12 days later, splenic DCs were enriched by MACS and purified into CD3-B220-CD8a+CD11c+ and CD3-B220-CD8a-CD11c+ cells by FACS cell sorter.
Project description:Lymphoid organs contain a B220(+)CD11c(+)NK1.1(+) cell population that was recently characterized as a novel dendritic cell (DC) subset that functionally overlaps with natural killer (NK) cells and plasmacytoid DCs (PDCs). Using Siglec-H and NK1.1 markers, we unambiguously dissected B220(+)CD11c(+) cells and found that PDCs are the only professional interferon (IFN)-alpha-producing cells within this heterogeneous population. In contrast, B220(+)CD11c(+)NK1.1(+) cells are a discrete NK cell subset capable of producing higher levels of IFN-gamma than conventional NK cells. Unlike DCs, only a minute fraction of B220(+)CD11c(+)NK1.1(+) cells in the spleen expressed major histocompatibility complex class II ex vivo or after stimulation with CpG. Consistent with being a NK cell subset, B220(+)CD11c(+)NK1.1(+) cells depended primarily on interleukin 15 and common cytokine receptor gamma chain signaling for their development. In terms of function, expression of distinctive cell surface receptors, and location in lymphoid organs, NK1.1(+)B220(+)CD11c(+) appear to be the murine equivalent of human CD56(bright) NK cells.
Project description:Beta-catenin signaling has recently been tied to the emergence of tolerogenic dendritic cells (DCs). In this article, we demonstrate a novel role for beta-catenin in directing DC subset development through IFN regulatory factor 8 (IRF8) activation. We found that splenic DC precursors express beta-catenin, and DCs from mice with CD11c-specific constitutive beta-catenin activation upregulated IRF8 through targeting of the Irf8 promoter, leading to in vivo expansion of IRF8-dependent CD8a+, plasmacytoid, and CD103+ CD11b2 DCs. beta-catenin–stabilized CD8a+ DCs secreted elevated IL-12 upon in vitro microbial stimulation, and pharmacological beta-catenin inhibition blocked this response in wild-type cells. Upon infections with Toxoplasma gondii and vaccinia virus, mice with stabilized DC beta-catenin displayed abnormally high Th1 and CD8+ T lymphocyte responses, respectively. Collectively, these results reveal a novel and unexpected function for beta-catenin in programming DC differentiation toward subsets that orchestrate proinflammatory immunity to infection.
Project description:Multiple subsets of FLT3L-dependent dendritic cells (DCs) control T cell tolerance and immunity. In mouse tissues, CD8α-like DCs are identified by CD103 expression. This DC subset efficiently enters lymph nodes and cross-presents antigens, rendering CD103+ DCs promising targets for therapeutic tolerance induction or vaccination. However, only limited numbers of CD103+ DCs can be isolated with current methods. Moreover, bone marrow cultures with FLT3L produce complex mixtures of DC subsets. We developed a novel method for generating large numbers of Batf3-dependent CD103+ DCs. We used microarray analysis to compare in vitro generated CD103+ and CD103- DCs and correlated their expression patterns to published profiles and signatures of DC subsets. Overall design: We generated iCD103 DCs according to our new method. We sorted CD11c+B220-CD103hi and CD11c+B220-CD103- DC subsets and processed these populations for RNA extraction and hybridization to Agilent microarrays.
Project description:Interferon-producing killer dendritic cells (IKDCs) are a recently described subset of CD11c(lo)B220(+) cells that share phenotypic and functional properties of DCs and natural killer (NK) cells (Chan, C.W., E. Crafton, H.N. Fan, J. Flook, K. Yoshimura, M. Skarica, D. Brockstedt, T.W. Dubensky, M.F. Stins, L.L. Lanier, et al. 2006. Nat. Med. 12:207-213; Taieb, J., N. Chaput, C. Menard, L. Apetoh, E. Ullrich, M. Bonmort, M. Pequignot, N. Casares, M. Terme, C. Flament, et al. 2006. Nat. Med. 12:214-219). IKDC development appears unusual in that cytokines using the interleukin (IL)-2 receptor beta (IL-2Rbeta) chain but not those using the common gamma chain (gamma(c)) are necessary for their generation. By directly comparing Rag2(-/-)gamma(c)(-/y), Rag2(-/-)IL-2Rbeta(-/-), Rag2(-/-)IL-15(-/-), and Rag2(-/-)IL-2(-/-) mice, we demonstrate that IKDC development parallels NK cell development in its strict IL-15 dependence. Moreover, IKDCs uniformly express NK-specific Ncr-1 transcripts (encoding NKp46), whereas NKp46(+) cells are absent in Ncr1(gfp/+)gamma(c)(-/y) mice. Distinguishing features of IKDCs (CD11c(lo)B220(+)MHC-II(+)) were carefully examined on developing NK cells in the bone marrow and on peripheral NK cells. As B220 expression was heterogeneous, defining B220(lo) versus B220(hi) NK1.1(+) NK cells could be considered as arbitrary, and few phenotypic differences were noted between NK1.1(+) NK cells bearing different levels of B220. CD11c expression did not correlate with B220 or major histocompatibility complex (MHC) class II (MHC-II) expression, and most MHC-II(+) NK1.1(+) cells did not express B220 and were thus not IKDCs. Finally, CD11c, MHC-II, and B220 levels were up-regulated on NK1.1(+) cells upon activation in vitro or in vivo in a proliferation-dependent fashion. Our data suggest that the majority of CD11c(lo)B220(+) "IKDC-like" cells represent activated NK cells.
Project description:Retinoic acid (RA) produced by intestinal dendritic cells (DCs) imprints gut-homing specificity on lymphocytes and enhances Foxp3(+) regulatory T-cell differentiation. The expression of aldehyde dehydrogenase (ALDH) 1A in these DCs is essential for the RA production. However, it remains unclear how the steady-state ALDH1A expression is induced under specific pathogen-free (SPF) conditions. Here, we found that bone marrow-derived dendritic cells (BM-DCs) generated with granulocyte-macrophage colony-stimulating factor (GM-CSF) expressed Aldh1a2, an isoform of Aldh1a, but that fms-related tyrosine kinase 3 ligand-generated BM-DCs did not. DCs from mesenteric lymph nodes (MLN) and Peyer's patches (PP) of normal SPF mice expressed ALDH1A2, but not the other known RA-producing enzymes. Employing a flow cytometric method, we detected ALDH activities in 10-30% of PP-DCs and MLN-DCs. They were CD11c(high)CD4(-/low)CD8alpha(intermediate)CD11b(-/low) F4/80(low/intermediate)CD45RB(low)CD86(high)MHC class II(high)B220(-)CD103(+). Equivalent levels of aldehyde dehydrogenase activity (ALDHact) and ALDH1A2 expression were induced synergistically by GM-CSF and IL-4 in splenic DCs in vitro. In BM-DCs, however, additional signals via Toll-like receptors or RA receptors were required for inducing the equivalent levels. The generated ALDH1A2(+) DCs triggered T cells to express gut-homing receptors or Foxp3. GM-CSF receptor-deficient or vitamin A-deficient mice exhibited marked reductions in the ALDHact in intestinal DCs and the T cell number in the intestinal lamina propria, whereas IL-4 receptor-mediated signals were dispensable. GM-CSF(+)CD11c(-)F4/80(+) cells existed constitutively in the intestinal tissues. The results suggest that GM-CSF and RA itself are pivotal among multiple microenvironment factors that enable intestinal DCs to produce RA.
Project description:Follicular dendritic cells (FDCs) form a reticular FDC network in the lymphoid follicle that is essential for the retention and presentation of native antigens in the form of antigen-antibody immune complexes (ICs) to B cells during secondary immune response. Although the presence of migrating precursors of FDCs has been hypothesized, their entity has not been elucidated. Here we report the identification of murine splenic CD19(-)CD11c(-)CD35(+)B220(+) cells as an inducer of FDC network formation. We demonstrated that CD19(-)-CD11c(-)CD35(+)B220(+) cells, together with stromal cells, had the remarkable ability to form lymphoid-follicle-like structures that contained B220(+)FDC-M1(+) reticular cells originally derived from CD19(-)-CD11c(-)CD35(+)B220(+) cells in the CD35(+) reticulum. Our results indicate that CD19(-)CD11c(-)CD35(+)B220(+) cells function as an inducer of FDC network formation and that the interaction between CD19(-)CD11c(-)CD35(+)B220(+) cells and stromal cells is required to initiate lymphoid follicle formation.
Project description:The environmental contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), causes immune suppression via activation of the aryl hydrocarbon receptor. Dendritic cells (DCs), the professional antigen-presenting cells in the immune system, are adversely affected by TCDD. We hypothesized that TCDD alters DC homeostasis, resulting in a loss of DCs in naive mice. To test this hypothesis, C57Bl/6 mice were gavaged with either vehicle or an immunosuppressive dose of TCDD (15 microg/kg). TCDD exposure decreased the frequency and number of splenic CD11c(high) DCs on day 7 when compared with vehicle-treated controls. TCDD increased the expression of CD86 and CD54, while decreasing the frequency of splenic CD11c(high) DCs expressing CD11a and major histocompatibility complex (MHC) class II. Moreover, TCDD selectively decreased the CD11c(high)CD8alpha(-)33D1(+) splenic DCs specialized at activating CD4(+) T cells but did not affect the regulatory CD11c(high)CD8alpha(+)DEC205(+) splenic DCs. TCDD did not alter the number or frequency of CD11c(low) splenic DCs but decreased their MHC class II and CD11a expression. Loss of splenic CD11c(high) DCs was independent of Fas-mediated apoptosis and was not due to alterations in the numbers of common DC precursors in the bone marrow or their ability to generate steady-state DCs in vitro. Instead, increased CCR7 expression on CD11c(high) DCs suggested involvement of a migratory event. Popliteal and brachial lymph node CD11c(+) cells showed elevated levels of MHC class II and CD40 following TCDD exposure. Collectively, this study shows the presence of a TCDD-sensitive splenic DC subpopulation in naive mice, suggesting that TCDD may induce suppression of T-cell-mediated immunity by disrupting DC homeostasis.
Project description:Dendritic cells (DCs) are critical immune regulators involved in autoimmune diseases, but exploiting them clinically requires a detailed picture on the mechanisms orchestrating their development. DNA methylation is attractive in this regard because it is reversible and as such allows therapeutic manipulation. Combining single cell transplantation assays with whole-genome methylation assessment and with mice expressing reduced DNA methyltransferase 1 levels, we show that conventional and plasmacytoid DCs arise from myeloid-restricted hematopoietic stem cells (HSCs), suggesting that both subsets can develop independently of the lymphoid pathway. DC commitment by these HSCs requires an intrinsically high methylation threshold to establish expression of DC genes, particularly the Flt3 cytokine receptor. Reducing methylation depleted DCs and ameliorated systemic lupus erythematosus in mice. These studies shed novel light on the DC origin, show how lineage- and subset-specific methylation dynamics regulate DC fate and provide a potential rationale for targeting DCs in autoimmunity by hypomethylating agents. Overall design: Tagmentation-based whole-genome bisulfite sequencing (TWGBS) of MDPs (Lin- cKithi CD115+ Flt3+, 2 Replicates), Monocytes (CD11b+ Ly6Chi B220- CD5- CD8a- Ter119- SiglecF- Ly6G- FceRI-, 3 Replicates), cMoPs (Lin- cKithi CD115+ Flt3- CD11b- Ly6C+, 2 Replicates), CDPs (Lin- cKitlo CD115+ Flt3+, 4 replicates), pDCs (PDCA+ CD11cint, 3 replicates), cDC CD8a+ (MHC II+ CD11chi CD11b- CD8a+, 3 replicates) and cDC CD11b+ (MHC II+ CD11chi CD11b+ CD8a-, 3 replicates). Lineage markers (Lin): (B220, CD4, CD8a, CD3, CD19, CD11c, Ter119, NK1.1, expanded by antibodies to CD11b and Gr-1 for isolation of MDP and CDP or Ly-6G for cMoP isolation). For each replicate, four separate TWGBS libraries were prepared and pools of four libraries were sequenced on three separate HiSeq2000 lanes using the 125bp paired-end mode.