Homeostatic NF-κB Signaling in Steady-State Migratory Dendritic Cells Regulates Immune Homeostasis and Tolerance

SummaryMigratory non-lymphoid tissue dendritic cells (NLT-DCs) transport antigens to lymph nodes (LNs) and are required for protective immune responses in the context of inflammation and to promote tolerance to self-antigens in steady-state. However, the molecular mechanisms that elicit steady-state NLT-DC maturation and migration are unknown. By comparing the transcriptome of NLT-DCs in the skin with their migratory counterparts in draining LNs, we have identified a novel NF-κB-regulated gene network specific to migratory DCs. We show that targeted deletion of IKKβ in DCs, a major activator of NF-κB, prevents NLT-DC accumulation in LNs and compromises regulatory T cell conversion in vivo. This was associated with impaired tolerance and autoimmunity. NF-κB is generally considered the prototypical pro-inflammatory transcription factor, but this study describes a role for NF-κB signaling in DCs for immune homeostasis and tolerance that could have implications in autoimmune diseases and immunity

Claudine Drame, Des films pour le dire, reflets de la Shoah au cinéma 1945-1985

L’année 2007 a été marquée par la sortie de deux ouvrages relatifs à la représentation au cinéma du génocide des Juifs d’Europe : celui de Claudine Drame et Le cinéma et la Shoah, un art à l’épreuve de la tragédie du XXe siècle, coordonné par Jean-Michel Frodon aux éditions Cahiers du Cinéma. Ces deux livres partent du même principe : jeter un regard rétrospectif sur des dizaines d’années de représentation des crimes génocidaires nazis au cinéma, en concluant sur la suprématie du film Shoah d..

I kappa B kinase alpha (IKKα) activity is required for functional maturation of dendritic cells and acquired immunity to infection

Dendritic cells (DC) are required for priming antigen-specific T cells and acquired immunity to many important human pathogens, including Mycobacteriuim tuberculosis (TB) and influenza. However, inappropriate priming of auto-reactive T cells is linked with autoimmune disease. Understanding the molecular mechanisms that regulate the priming and activation of naïve T cells is critical for development of new improved vaccines and understanding the pathogenesis of autoimmune diseases. The serine/threonine kinase IKKα (CHUK) has previously been shown to have anti-inflammatory activity and inhibit innate immunity. Here, we show that IKKα is required in DC for priming antigen-specific T cells and acquired immunity to the human pathogen Listeria monocytogenes. We describe a new role for IKKα in regulation of IRF3 activity and the functional maturation of DC. This presents a unique role for IKKα in dampening inflammation while simultaneously promoting adaptive immunity that could have important implications for the development of new vaccine adjuvants and treatment of autoimmune diseases

Leukocyte population dynamics and detection of IL-9 as a major cytokine at the mouse fetal-maternal interface.

International audienceDespite much interest in the mechanisms regulating fetal-maternal interactions, information on leukocyte populations and major cytokines present in uterus and placenta remains fragmentary. This report presents a detailed and quantitative study of leukocyte populations at the mouse fetal-maternal interface, including a comparison between pregnancies from syngeneic and allogeneic crosses. Our results provide evidence for drastic differences not only in the composition of leukocyte populations in the uterus during pregnancy, but also between uterine and placental tissues. Interestingly, we have observed a significant decrease in the number of myeloid Gr1+ cells including monocytes, and myeloid CD11c+ cells including DCs in placenta from an allogeneic pregnancy. In addition, we have compared the expression levels of a panel of cytokines in non-pregnant (NP) or pregnant mouse uterus, in placenta, or in their isolated resident leukocytes. Qualitative and quantitative differences have emerged between NP, pregnant uterus and placenta. Unexpectedly, IL-9 was the major cytokine in NP uterus, and was maintained at high levels during pregnancy both in uterus and placenta. Moreover, we have found that pregnancy is associated with an increase in uterine IL-1a and a significant decrease in uterine G-CSF and GM-CSF. Comparing allogeneic versus syngeneic pregnancy, less allogeneic placental pro-inflammatory cytokines CCL2 (MCP-1), CXCL10 (IP-10) and more IL1-α in whole uterus was reproducibly observed. To our knowledge, this is the first report showing a detailed overview of the leukocyte and cytokine repertoire in the uterus of virgin females and at the fetal-maternal interface, including a comparison between syngeneic and allogeneic pregnancy. This is also the first evidence for the presence of IL-9 in NP uterus and at the maternal-fetal interface, suggesting a major role in the regulation of local inflammatory or immune responses potentially detrimental to the conceptus

Antibody and dilutions used for flow cytometry staining.

<p>NA: not applicable.</p><p>Antibody and dilutions used for flow cytometry staining.</p

Analyses of immune cell populations present in the uterus of NP or pregnant mice, and in placenta (16.5 d<i>pc</i>).

<p>Only viable cells excluding propidium iodide were analysed. Enriched leukocytes from NP (A,B) or pregnant (16.5 d<i>pc</i>) uterus (C,D) and placenta (E,F) were analysed by flow cytometry. R2-gated cells (left, cf. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107267#pone-0107267-g002" target="_blank">Figure 2</a>) were analysed on the basis of the following cell surface markers: TCRβ⁺/CD4⁺ (CD4 T cells); TCRβ⁺/CD8⁺ (CD8 T cells); NK1.1⁺/TCRβ⁻ (NK cells); TCRβ⁺/NK1.1⁺ (NKT cells); CD19⁺/B220⁺ (B cells); Gr1⁺/CD11b⁺ (myeloid Gr1+ cells including monocytes); Gr1^−/CD11c⁺/CD11b^Hi/low (myeloid CD11c+ cells including DCs). R1-gated cells (right, cf. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107267#pone-0107267-g002" target="_blank">Figure 2</a>) were analysed on the basis of the following cell surface markers: Gr1⁺/CD11b⁺ (Granulocytes); CD11b^Hi/Gr1⁺/Gr1^+/−/CD11c^+/− (Highly granulosity cells or HGC). The results are representative from a typical experiment of a pool of 7 mice (A, B) or from a single mouse (C, D, E, F). The experiment was repeated at least twice with 3–6 animals per assay.</p

Cytokine and chemokine expression levels in placentae from syngeneic or allogeneic pregnancies (day 16.5 <i>pc</i>).

<p>Analyses were performed on the placentas from the same pregnant mice as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107267#pone-0107267-g008" target="_blank">Figure 8</a>. Proteins were measured from whole placenta (A), or from enriched placental leukocytes (B) from syngeneic or allogeneic pregnancies (note the important scale variations). Grey bars: syngeneic pregnancy, black bars: allogeneic pregnancy. Data are from 4 to 5 different samples. (*) p≤0.05, (**) p≤0.005, (***) p≤0.001.</p

Quantification of uterine and placental cytokines and chemokines in syngeneic pregnancy (day 16.5 <i>pc</i>).

<p>Uterine and placental tissues were prepared as described in Materials and Methods : (A) Uteri from NP mice, (B) Uteri from <b>syngeneic</b> pregnancy (day 16.5 d<i>pc</i>), (C) Placenta from <b>syngeneic</b> pregnancy (same animals). Samples were analyzed simultaneously for the following 22 cytokines: IL-1α, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-9, IL-10, IL-12(p70), IL-13, IL-15, IL-17, CSF2 (GM-CSF), CSF3 (G-CSF), IFNγ, CXCL10 (IP-10), CXCL1 (KC), CCL2 (MCP-1), CCL3 (MIP-1α), CCL5 (RANTES), TNF-α. Only IL-9, IL-10, GM-CSF (CSF2), G-CSF (CSF3), CXCL10 (IP-10), IL-1α, CCL3 (MIP-1α), CXCL1 (KC), CCL2 (MCP-1) yielded reproducibly significant measurements and have been presented. Striped bars: whole organ, black bars: enriched leukocytes from the same organ. Data are from 4 to 5 different samples. Statistically significant differences: (*) p≤0.05, (***) p≤0.001.</p

Cytokine and chemokine expression levels in uterus from NP mice versus syngeneic or allogeneic pregnancies (day 16.5 <i>pc</i>).

<p>The same protocol as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107267#pone-0107267-g007" target="_blank">Figure 7</a> was followed. Proteins were measured from whole uterus (A), or from enriched uterine leukocytes (B) from NP uterus, or syngeneic or allogeneic pregnancies (note the important scale variations). Striped bars: NP uterus, grey bars: syngeneic pregnancy at 16.5 d<i>pc</i>, black bars: allogeneic pregnancy at 16.5 d<i>pc</i>. Data are from 4 to 5 different samples. (*) p≤0.05, (**) p≤0.005, (***) p≤0.001.</p

High granulosity cells in non pregnant uterus are primarily eosinophils.

<p>Viable R1- or R2- gated CD45.2+ cells from NP uterus were analysed by FACS stained for APC and granulocytes markers (CD11b, CD24, CD11b, F4/80, Ly6C, Ly6G, MHC class II and CCR2) (A, B and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107267#pone-0107267-t001" target="_blank">Table 1</a>) and for NK and T cell markers (CD11b, NK1.1, CD3ε, CD8α and CD4) (B and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107267#pone-0107267-t001" target="_blank">Table 1</a>). The experiment was repeated twice with 6 females each time (A, B). Viable CD45.2+, CD11b+, F4/80+ R1 (C) or R2 (D) cells were sorted by flow cytometry and spun onto Super + glass microscope slides using a Cytospin cytofuge. Cells were fixed with methanol and stained with Wright-Giemsa. Pictures were taken on a Nikon H600L microscope equipped with a DS-Fi2-Nikon camera (C, D). The experiment was performed twice with at least 5 females each time.</p