Immune complexes stimulate CCR7-dependent dendritic cell migration to lymph nodes

PubMed Central

Clatworthy, Menna R.; Aronin, Caren E. Petrie; Mathews, Rebeccah J.; Morgan, Nicole; Smith, Kenneth G.C.; Germain, Ronald N.

2014-01-01

Antibodies are critical for defence against a variety of microbes but may also be pathogenic in some autoimmune diseases. Many effector functions of antibody are mediated by Fcγ receptors (FcγRs), which are found on most immune cells, including dendritic cells (DCs). DCs are important antigen presenting cells and play a central role in inducing antigen-specific tolerance or immunity1,2. Following antigen acquisition in peripheral tissues, DCs migrate to draining lymph nodes via lymphatics to present antigen to T cells. In this study we demonstrate that FcγR engagement by IgG immune complexes (IC) stimulates DC migration from peripheral tissues to the paracortex of draining lymph nodes. In vitro, IC-stimulated murine and human DCs showed enhanced directional migration in a CCL19 gradient and increased CCR7 expression. Using intravital two-photon microscopy, we observed that local administration of IC resulted in dermal DC mobilisation. We confirmed that dermal DC migration to lymph nodes was CCR7-dependent and increased in the absence of the inhibitory receptor, FcγRIIb. These observations have relevance to autoimmunity, because autoantibody-containing serum from mice and humans with SLE also increased dermal DC migration to lymph nodes in vivo, suggesting that this process may occur in lupus, potentially driving the inappropriate localisation of autoantigen-bearing DCs. PMID:25384086

Arc/Arg3.1 governs inflammatory dendritic cell migration from the skin and thereby controls T cell activation.

PubMed

Ufer, Friederike; Vargas, Pablo; Engler, Jan Broder; Tintelnot, Joseph; Schattling, Benjamin; Winkler, Hana; Bauer, Simone; Kursawe, Nina; Willing, Anne; Keminer, Oliver; Ohana, Ora; Salinas-Riester, Gabriela; Pless, Ole; Kuhl, Dietmar; Friese, Manuel A

2016-09-23

Skin-migratory dendritic cells (migDCs) are pivotal antigen-presenting cells that continuously transport antigens to draining lymph nodes and regulate immune responses. However, identification of migDCs is complicated by the lack of distinguishing markers, and it remains unclear which molecules determine their migratory capacity during inflammation. We show that, in the skin, the neuronal plasticity molecule activity-regulated cytoskeleton-associated protein/activity-regulated gene 3.1 (Arc/Arg3.1) was strictly confined to migDCs. Mechanistically, Arc/Arg3.1 was required for accelerated DC migration during inflammation because it regulated actin dynamics through nonmuscle myosin II. Accordingly, Arc/Arg3.1-dependent DC migration was critical for mounting T cell responses in experimental autoimmune encephalomyelitis and allergic contact dermatitis. Thus, Arc/Arg3.1 was restricted to migDCs in the skin and drove fast DC migration by exclusively coordinating cytoskeletal changes in response to inflammatory challenges. These findings commend Arc/Arg3.1 as a universal switch in migDCs that may be exploited to selectively modify immune responses. Copyright © 2016, American Association for the Advancement of Science.

Antigen-loaded Dendritic Cell Migration: MR Imaging in a Pancreatic Carcinoma Model

PubMed Central

Li, Weiguo; Procissi, Daniele; Li, Kangan; Sheu, Alexander Y.; Gordon, Andrew C.; Guo, Yang; Khazaie, Khashayarsha; Huan, Yi; Han, Guohong; Larson, Andrew C.

2015-01-01

Purpose To test the following hypotheses in a murine model of pancreatic cancer: (a) Vaccination with antigen-loaded iron-labeled dendritic cells reduces T2-weighted signal intensity at magnetic resonance (MR) imaging within peripheral draining lymph nodes (LNlymph nodes) and (b) such signal intensity reductions are associated with tumor size changes after dendritic cell vaccination. Materials and Methods The institutional animal care and use committee approved this study. Panc02 cells were implanted into the flanks of 27 C57BL/6 mice bilaterally. After tumors reached 10 mm, cell viability was evaluated, and iron-labeled dendritic cell vaccines were injected into the left hind footpad. The mice were randomly separated into the following three groups (n = 9 in each): Group 1 was injected with 1 million iron-labeled dendritic cells; group 2, with 2 million cells; and control mice, with 200 mL of phosphate-buffered saline. T1- and T2-weighted MR imaging of labeled dendritic cell migration to draining LNlymph nodes was performed before cell injection and 6 and 24 hours after injection. The signal-to-noise ratio (SNRsignal-to-noise ratio) of the draining LNlymph nodes was measured. One-way analysis of variance (ANOVAanalysis of variance) was used to compare Prussian blue–positive dendritic cell measurements in LNlymph nodes. Repeated-measures ANOVAanalysis of variance was used to compare in vivo T2-weighted SNRsignal-to-noise ratio LNlymph node measurements between groups over the observation time points. Results Trypan blue assays showed no significant difference in mean viability indexes (unlabeled vs labeled dendritic cells, 4.32% ± 0.69 [standard deviation] vs 4.83% ± 0.76; P = .385). Thirty-five days after injection, the mean left and right flank tumor sizes, respectively, were 112.7 mm2 ± 16.4 and 109 mm2 ± 24.3 for the 1-million dendritic cell group, 92.2 mm2 ± 9.9 and 90.4 mm2 ± 12.8 for the 2-million dendritic cell group, and 193.7 mm2 ± 20.9 and 189.4 mm2 ± 17.8 for the control group (P = .0001 for control group vs 1-million cell group; P = .00007 for control group vs 2-million cell group). There was a correlation between postinjection T2-weighted SNRsignal-to-noise ratio decreases in the left popliteal LNlymph node 24 hours after injection and size changes at follow-up for tumors in both flanks (R = 0.81 and R = 0.76 for left and right tumors, respectively). Conclusion MR imaging approaches can be used for quantitative measurement of accumulated iron-labeled dendritic cell–based vaccines in draining LNlymph nodes. The amount of dendritic cell–based vaccine in draining LNlymph nodes correlates well with observed protective effects. © RSNA, 2014 Online supplemental material is available for this article. PMID:25222066

Induction of dendritic cell migration upon Toxoplasma gondii infection potentiates parasite dissemination.

PubMed

Lambert, Henrik; Hitziger, Niclas; Dellacasa, Isabel; Svensson, Mattias; Barragan, Antonio

2006-10-01

The processes leading to systemic dissemination of the obligate intracellular parasite Toxoplasma gondii remain unelucidated. In vitro studies on human and murine dendritic cells (DC) revealed that active invasion of DC by Toxoplasma induces a state of hypermotility in DC, enabling transmigration of infected DC across endothelial cell monolayers in the absence of chemotactic stimuli. Infected DC exhibited upregulation of maturation markers and co-stimulatory molecules. While modulation of cell adhesion molecules CD11/CD18 was similar for Toxoplasma-infected DC and lipopolysaccharide (LPS)-matured DC, Toxoplasma-infected DC did not exhibit upregulation of CD54/ICAM-1. Induction of host cell migration in vitro required live intracellular parasite(s) and was inhibited by uncoupling the Gi-protein signalling pathway with pertussis toxin, but did not depend on CCR5, CCR7 or Toll/interleukin-1 receptor signalling. When migration of Toxoplasma-infected DC was compared with migration of LPS-stimulated DC in vivo, similar or higher numbers of Toxoplasma-infected DC reached the mesenteric lymph nodes and spleen respectively. Adoptive transfer of Toxoplasma-infected DC resulted in more rapid dissemination of parasites to distant organs and in exacerbation of infection compared with inoculation with free parasites. Altogether, these findings show that Toxoplasma is able to subvert the regulation of host cell motility and likely exploits the host's natural pathways of cellular migration for parasite dissemination.

Space exploration by dendritic cells requires maintenance of myosin II activity by IP3 receptor 1

PubMed Central

Solanes, Paola; Heuzé, Mélina L; Maurin, Mathieu; Bretou, Marine; Lautenschlaeger, Franziska; Maiuri, Paolo; Terriac, Emmanuel; Thoulouze, Maria-Isabel; Launay, Pierre; Piel, Matthieu; Vargas, Pablo; Lennon-Duménil, Ana-Maria

2015-01-01

Dendritic cells (DCs) patrol the interstitial space of peripheral tissues. The mechanisms that regulate their migration in such constrained environment remain unknown. We here investigated the role of calcium in immature DCs migrating in confinement. We found that they displayed calcium oscillations that were independent of extracellular calcium and more frequently observed in DCs undergoing strong speed fluctuations. In these cells, calcium spikes were associated with fast motility phases. IP3 receptors (IP3Rs) channels, which allow calcium release from the endoplasmic reticulum, were identified as required for immature DCs to migrate at fast speed. The IP3R1 isoform was further shown to specifically regulate the locomotion persistence of immature DCs, that is, their capacity to maintain directional migration. This function of IP3R1 results from its ability to control the phosphorylation levels of myosin II regulatory light chain (MLC) and the back/front polarization of the motor protein. We propose that by upholding myosin II activity, constitutive calcium release from the ER through IP3R1 maintains DC polarity during migration in confinement, facilitating the exploration of their environment. PMID:25637353

Magnetic Enrichment of Dendritic Cell Vaccine in Lymph Node with Fluorescent-Magnetic Nanoparticles Enhanced Cancer Immunotherapy

PubMed Central

Jin, Honglin; Qian, Yuan; Dai, Yanfeng; Qiao, Sha; Huang, Chuan; Lu, Lisen; Luo, Qingming; Chen, Jing; Zhang, Zhihong

2016-01-01

Dendritic cell (DC) migration to the lymph node is a key component of DC-based immunotherapy. However, the DC homing rate to the lymphoid tissues is poor, thus hindering the DC-mediated activation of antigen-specific T cells. Here, we developed a system using fluorescent magnetic nanoparticles (α-AP-fmNPs; loaded with antigen peptide, iron oxide nanoparticles, and indocyanine green) in combination with magnetic pull force (MPF) to successfully manipulate DC migration in vitro and in vivo. α-AP-fmNPs endowed DCs with MPF-responsiveness, antigen presentation, and simultaneous optical and magnetic resonance imaging detectability. We showed for the first time that α-AP-fmNP-loaded DCs were sensitive to MPF, and their migration efficiency could be dramatically improved both in vitro and in vivo through MPF treatment. Due to the enhanced migration of DCs, MPF treatment significantly augmented antitumor efficacy of the nanoparticle-loaded DCs. Therefore, we have developed a biocompatible approach with which to improve the homing efficiency of DCs and subsequent anti-tumor efficacy, and track their migration by multi-modality imaging, with great potential applications for DC-based cancer immunotherapy. PMID:27698936

Space exploration by dendritic cells requires maintenance of myosin II activity by IP3 receptor 1.

PubMed

Solanes, Paola; Heuzé, Mélina L; Maurin, Mathieu; Bretou, Marine; Lautenschlaeger, Franziska; Maiuri, Paolo; Terriac, Emmanuel; Thoulouze, Maria-Isabel; Launay, Pierre; Piel, Matthieu; Vargas, Pablo; Lennon-Duménil, Ana-Maria

2015-03-12

Dendritic cells (DCs) patrol the interstitial space of peripheral tissues. The mechanisms that regulate their migration in such constrained environment remain unknown. We here investigated the role of calcium in immature DCs migrating in confinement. We found that they displayed calcium oscillations that were independent of extracellular calcium and more frequently observed in DCs undergoing strong speed fluctuations. In these cells, calcium spikes were associated with fast motility phases. IP₃ receptors (IP₃Rs) channels, which allow calcium release from the endoplasmic reticulum, were identified as required for immature DCs to migrate at fast speed. The IP₃R1 isoform was further shown to specifically regulate the locomotion persistence of immature DCs, that is, their capacity to maintain directional migration. This function of IP₃R1 results from its ability to control the phosphorylation levels of myosin II regulatory light chain (MLC) and the back/front polarization of the motor protein. We propose that by upholding myosin II activity, constitutive calcium release from the ER through IP₃R1 maintains DC polarity during migration in confinement, facilitating the exploration of their environment. © 2015 Institut Curie/Inserm. Published under the terms of the CC BY NC ND 4.0 license.

Dendritic Cell Transmigration through Brain Microvessel Endothelium Is Regulated by MIP-1α Chemokine and Matrix Metalloproteinases1

PubMed Central

Zozulya, Alla L.; Reinke, Emily; Baiu, Dana C.; Karman, Jozsef; Sandor, Matyas; Fabry, Zsuzsanna

2007-01-01

Dendritic cells (DCs) accumulate in the CNS during inflammatory diseases, but the exact mechanism regulating their traffic into the CNS remains to be defined. We now report that MIP-1α increases the transmigration of bone marrow-derived, GFP-labeled DCs across brain microvessel endothelial cell monolayers. Furthermore, occludin, an important element of endothelial tight junctions, is reorganized when DCs migrate across brain capillary endothelial cell monolayers without causing significant changes in the barrier integrity as measured by transendothelial electrical resistance. We show that DCs produce matrix metalloproteinases (MMP) -2 and -9 and GM6001, an MMP inhibitor, decreases both baseline and MIP-1α -induced DC transmigration. These observations suggest that DC transmigration across brain endothelial cell monolayers is partly MMP dependent. The migrated DCs express higher levels of CD40, CD80, and CD86 costimulatory molecules and induce T cell proliferation, indicating that the transmigration of DCs across brain endothelial cell monolayers contributes to the maintenance of DC Ag-presenting function. The MMP dependence of DC migration across brain endothelial cell monolayers raises the possibility that MMP blockers may decrease the initiation of T cell recruitment and neuroinflammation in the CNS. PMID:17182592

Morphologic Integration of Hilar Ectopic Granule Cells into Dentate Gyrus Circuitry in the Pilocarpine Model of Temporal Lobe Epilepsy

PubMed Central

Cameron, Michael C.; Zhan, Ren-Zhi; Nadler, J. Victor

2014-01-01

After pilocarpine-induced status epilepticus, many granule cells born into the postseizure environment migrate aberrantly into the dentate hilus. Hilar ectopic granule cells (HEGCs) are hyperexcitable and may therefore increase circuit excitability. This study determined the distribution of their axons and dendrites. HEGCs and normotopic granule cells were filled with biocytin during whole-cell patch clamp recording in hippocampal slices from pilocarpine-treated rats. The apical dendrite of 86% of the biocytin-labeled HEGCs extended to the outer edge of the dentate molecular layer. The total length and branching of HEGC apical dendrites that penetrated the molecular layer were significantly reduced compared with apical dendrites of normotopic granule cells. HEGCs were much more likely to have a hilar basal dendrite than normotopic granule cells. They were about as likely as normotopic granule cells to project to CA3 pyramidal cells within the slice, but were much more likely to send at least one recurrent mossy fiber into the molecular layer. HEGCs with burst capability had less well-branched apical dendrites than nonbursting HEGCs, their dendrites were more likely to be confined to the hilus, and some exhibited dendritic features similar to those of immature granule cells. HEGCs thus have many paths along which to receive synchronized activity from normotopic granule cells and to transmit their own hyperactivity to both normotopic granule cells and CA3 pyramidal cells. They may therefore contribute to the highly interconnected granule cell hubs that have been proposed as crucial to development of a hyperexcitable, potentially seizure-prone circuit. PMID:21455997

Scaffolding protein Gab1 regulates myeloid dendritic cell migration in allergic asthma

PubMed Central

Zhang, Yun; Xu, Yun; Liu, Shuwan; Guo, Xiaohong; Cen, Dong; Xu, Jiaqi; Li, Heyuan; Li, Kaijun; Zeng, Chunlai; Lu, Linrong; Zhou, Yiting; Shen, Huahao; Cheng, Hongqiang; Zhang, Xue; Ke, Yuehai

2016-01-01

Asthma is a common allergic disorder involving a complex interplay among multiple genetic and environmental factors. Recent studies identified genetic variants of human GAB1 as a novel asthma susceptibility factor. However, the functions of Gab1 in lung remain largely unexplored. In this study, we first observed an elevation of Gab1 level in peripheral blood mononuclear cells from asthmatic patients during acute exacerbation compared with convalescence. Mice with a selectively disrupted Gab1 in myeloid dendritic cells (mDCs) considerably attenuated allergic inflammation in experimental models of asthma. Further investigations revealed a prominent reduction in CCL19-mediated migration of Gab1-deficient mDCs to draining lymph nodes and subsequent impairment of Th2-driven adaptive activation. Mechanistically, Gab1 is an essential component of the CCL19/CCR7 chemokine axis that regulates mDC migration during asthmatic responses. Together, these findings provide the first evidence for the roles of Gab1 in lung, giving us deeper understanding of asthmatic pathogenesis. PMID:27811945

Depletion of host CCR7(+) dendritic cells prevented donor T cell tissue tropism in anti-CD3-conditioned recipients.

PubMed

He, Wei; Racine, Jeremy J; Johnston, Heather F; Li, Xiaofan; Li, Nainong; Cassady, Kaniel; Liu, Can; Deng, Ruishu; Martin, Paul; Forman, Stephen; Zeng, Defu

2014-07-01

We reported previously that anti-CD3 mAb treatment before hematopoietic cell transplantation (HCT) prevented graft-versus-host disease (GVHD) and preserved graft-versus-leukemia (GVL) effects in mice. These effects were associated with downregulated donor T cell expression of tissue-specific homing and chemokine receptors, marked reduction of donor T cell migration into GVHD target tissues, and deletion of CD103(+) dendritic cells (DCs) in mesenteric lymph nodes (MLN). MLN CD103(+) DCs and peripheral lymph node (PLN) DCs include CCR7(+) and CCR7(-) subsets, but the role of these DC subsets in regulating donor T cell expression of homing and chemokine receptors remain unclear. Here, we show that recipient CCR7(+), but not CCR7(-), DCs in MLN induced donor T cell expression of gut-specific homing and chemokine receptors in a retinoid acid-dependent manner. CCR7 regulated activated DC migration from tissue to draining lymph node, but it was not required for the ability of DCs to induce donor T cell expression of tissue-specific homing and chemokine receptors. Finally, anti-CD3 treatment depleted CCR7(+) but not CCR7(-) DCs by inducing sequential expansion and apoptosis of CCR7(+) DCs in MLN and PLN. Apoptosis of CCR7(+) DCs was associated with DC upregulation of Fas expression and natural killer cell but not T, B, or dendritic cell upregulation of FasL expression in the lymph nodes. These results suggest that depletion of CCR7(+) host-type DCs, with subsequent inhibition of donor T cell migration into GVHD target tissues, can be an effective approach in prevention of acute GVHD and preservation of GVL effects. Copyright © 2014 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

Synthetic and biogenic magnetite nanoparticles for tracking of stem cells and dendritic cells

NASA Astrophysics Data System (ADS)

Schwarz, Sebastian; Fernandes, Fabiana; Sanroman, Laura; Hodenius, Michael; Lang, Claus; Himmelreich, Uwe; Schmitz-Rode, Thomas; Schueler, Dirk; Hoehn, Mathias; Zenke, Martin; Hieronymus, Thomas

2009-05-01

Accurate delivery of cells to target organs is critical for success of cell-based therapies with stem cells or immune cells such as antigen-presenting dendritic cells (DC). Labeling with contrast agents before implantation provides a powerful means for monitoring cellular migration using magnetic resonance imaging (MRI). In this study, we investigated the uptake of fully synthesized or bacterial magnetic nanoparticles (MNPs) into hematopoietic Flt3 + stem cells and DC from mouse bone marrow. We show that (i) uptake of both synthetic and biogenic nanoparticles into cells endow magnetic activity and (ii) low numbers of MNP-loaded cells are readily detected by MRI.

CD40L+ CD4+ memory T cells migrate in a CD62P-dependent fashion into reactive lymph nodes and license dendritic cells for T cell priming

PubMed Central

Martín-Fontecha, Alfonso; Baumjohann, Dirk; Guarda, Greta; Reboldi, Andrea; Hons, Miroslav; Lanzavecchia, Antonio; Sallusto, Federica

2008-01-01

There is growing evidence that the maturation state of dendritic cells (DCs) is a critical parameter determining the balance between tolerance and immunity. We report that mouse CD4+ effector memory T (TEM) cells, but not naive or central memory T cells, constitutively expressed CD40L at levels sufficient to induce DC maturation in vitro and in vivo in the absence of antigenic stimulation. CD4+ TEM cells were excluded from resting lymph nodes but migrated in a CD62P-dependent fashion into reactive lymph nodes that were induced to express CD62P, in a transient or sustained fashion, on high endothelial venules. Trafficking of CD4+ TEM cells into chronic reactive lymph nodes maintained resident DCs in a mature state and promoted naive T cell responses and experimental autoimmune encephalomyelitis (EAE) to antigens administered in the absence of adjuvants. Antibodies to CD62P, which blocked CD4+ TEM cell migration into reactive lymph nodes, inhibited DC maturation, T cell priming, and induction of EAE. These results show that TEM cells can behave as endogenous adjuvants and suggest a mechanistic link between lymphocyte traffic in lymph nodes and induction of autoimmunity. PMID:18838544

Modulation of Female Genital Tract-Derived Dendritic Cell Migration and Activation in Response to Inflammatory Cytokines and Toll-Like Receptor Agonists.

PubMed

Shey, Muki S; Maharaj, Niren; Archary, Derseree; Ngcapu, Sinaye; Garrett, Nigel; Abdool Karim, Salim; Passmore, Jo-Ann S

2016-01-01

HIV transmission across the genital mucosa is a major mode of new HIV infections in women. The probability of infection may be influenced by several factors including recruitment and activation of HIV target cells, such as dendritic cells (DCs) and cytokine production, associated with genital inflammation. We evaluated the role of inflammatory cytokines and TLR signaling in migration and activation of genital tract DCs in the human cervical explant model. Hysterectomy tissues from 10 HIV-negative and 7 HIV-positive donor women were separated into ecto- and endocervical explants, and incubated with inflammatory cytokines (TNF-α, IL-1β, IL-8, MIP-1β) or agonists for TLR4 (LPS), TLR2/1 (PAM3) and TLR7/8 (R848). Migration (frequency) and activation (HLA-DR expression) of myeloid and plasmacytoid DCs and Langerhans cells were measured by flow cytometry. We observed that cytokines, LPS and PAM3 induced activation of migrating myeloid and plasmacytoid DCs. LPS induced a 3.6 fold lower levels of migration of plasmacytoid DCs from HIV-infected women compared with HIV-uninfected women (median activation indices of 2.932 vs 0.833). There was however a 4.5 fold increase in migration of Langerhans cells in HIV-infected compared with HIV-uninfected women in response to cytokines (median activation indices of 3.539 vs 0.77). Only TLR agonists induced migration and activation of DCs from endocervical explants. Hormonal contraception use was associated with an increase in activation of DC subsets in the endo and ectocervical explants. We conclude that inflammatory signals in the female genital tract induced DC migration and activation, with possible important implications for HIV susceptibility of cervical tissues.

Type I interferon dependence of plasmacytoid dendritic cell activation and migration

PubMed Central

Asselin-Paturel, Carine; Brizard, Géraldine; Chemin, Karine; Boonstra, Andre; O'Garra, Anne; Vicari, Alain; Trinchieri, Giorgio

2005-01-01

Differential expression of Toll-like receptor (TLR) by conventional dendritic cells (cDCs) and plasmacytoid DC (pDCs) has been suggested to influence the type of immune response induced by microbial pathogens. In this study we show that, in vivo, cDCs and pDCs are equally activated by TLR4, -7, and -9 ligands. Type I interferon (IFN) was important for pDC activation in vivo in response to all three TLR ligands, whereas cDCs required type I IFN signaling only for TLR9- and partially for TLR7-mediated activation. Although TLR ligands induced in situ migration of spleen cDC into the T cell area, spleen pDCs formed clusters in the marginal zone and in the outer T cell area 6 h after injection of TLR9 and TLR7 ligands, respectively. In vivo treatment with TLR9 ligands decreased pDC ability to migrate ex vivo in response to IFN-induced CXCR3 ligands and increased their response to CCR7 ligands. Unlike cDCs, the migration pattern of pDCs required type I IFN for induction of CXCR3 ligands and responsiveness to CCR7 ligands. These data demonstrate that mouse pDCs differ from cDCs in the in vivo response to TLR ligands, in terms of pattern and type I IFN requirement for activation and migration. PMID:15795237

Mast Cells Condition Dendritic Cells to Mediate Allograft Tolerance

PubMed Central

de Vries, Victor C.; Pino-Lagos, Karina; Nowak, Elizabeth C.; Bennett, Kathy A.; Oliva, Carla; Noelle, Randolph J.

2013-01-01

SUMMARY Peripheral tolerance orchestrated by regulatory T cells, dendritic cells (DCs), and mast cells (MCs) has been studied in several models including skin allograft tolerance. We now define a role for MCs in controlling DC behavior (“conditioning”) to facilitate tolerance. Under tolerant conditions, we show that MCs mediated a marked increase in tumor necrosis factor (TNFα)-dependent accumulation of graft-derived DCs in the dLN compared to nontolerant conditions. This increase of DCs in the dLN is due to the local production of granulocyte macrophage colony-stimulating factor (GM-CSF) by MCs that induces a survival advantage of graft-derived DCs. DCs that migrated to the dLN from the tolerant allograft were tolerogenic; i.e., they dominantly suppress T cell responses and control regional immunity. This study underscores the importance of MCs in conditioning DCs to mediate peripheral tolerance and shows a functional impact of peripherally produced TNFα and GM-CSF on the migration and function of tolerogenic DCs. PMID:22035846

Synthetic antimicrobial and LPS-neutralising peptides suppress inflammatory and immune responses in skin cells and promote keratinocyte migration.

PubMed

Pfalzgraff, Anja; Heinbockel, Lena; Su, Qi; Gutsmann, Thomas; Brandenburg, Klaus; Weindl, Günther

2016-08-11

The stagnation in the development of new antibiotics and the concomitant high increase of resistant bacteria emphasize the urgent need for new therapeutic options. Antimicrobial peptides are promising agents for the treatment of bacterial infections and recent studies indicate that Pep19-2.5, a synthetic anti-lipopolysaccharide (LPS) peptide (SALP), efficiently neutralises pathogenicity factors of Gram-negative (LPS) and Gram-positive (lipoprotein/-peptide, LP) bacteria and protects against sepsis. Here, we investigated the potential of Pep19-2.5 and the structurally related compound Pep19-4LF for their therapeutic application in bacterial skin infections. SALPs inhibited LP-induced phosphorylation of NF-κB p65 and p38 MAPK and reduced cytokine release and gene expression in primary human keratinocytes and dermal fibroblasts. In LPS-stimulated human monocyte-derived dendritic cells and Langerhans-like cells, the peptides blocked IL-6 secretion, downregulated expression of maturation markers and inhibited dendritic cell migration. Both SALPs showed a low cytotoxicity in all investigated cell types. Furthermore, SALPs markedly promoted cell migration via EGFR transactivation and ERK1/2 phosphorylation and accelerated artificial wound closure in keratinocytes. Peptide-induced keratinocyte migration was mediated by purinergic receptors and metalloproteases. In contrast, SALPs did not affect proliferation of keratinocytes. Conclusively, our data suggest a novel therapeutic target for the treatment of patients with acute and chronic skin infections.

Synthetic antimicrobial and LPS-neutralising peptides suppress inflammatory and immune responses in skin cells and promote keratinocyte migration

PubMed Central

Pfalzgraff, Anja; Heinbockel, Lena; Su, Qi; Gutsmann, Thomas; Brandenburg, Klaus; Weindl, Günther

2016-01-01

The stagnation in the development of new antibiotics and the concomitant high increase of resistant bacteria emphasize the urgent need for new therapeutic options. Antimicrobial peptides are promising agents for the treatment of bacterial infections and recent studies indicate that Pep19-2.5, a synthetic anti-lipopolysaccharide (LPS) peptide (SALP), efficiently neutralises pathogenicity factors of Gram-negative (LPS) and Gram-positive (lipoprotein/-peptide, LP) bacteria and protects against sepsis. Here, we investigated the potential of Pep19-2.5 and the structurally related compound Pep19-4LF for their therapeutic application in bacterial skin infections. SALPs inhibited LP-induced phosphorylation of NF-κB p65 and p38 MAPK and reduced cytokine release and gene expression in primary human keratinocytes and dermal fibroblasts. In LPS-stimulated human monocyte-derived dendritic cells and Langerhans-like cells, the peptides blocked IL-6 secretion, downregulated expression of maturation markers and inhibited dendritic cell migration. Both SALPs showed a low cytotoxicity in all investigated cell types. Furthermore, SALPs markedly promoted cell migration via EGFR transactivation and ERK1/2 phosphorylation and accelerated artificial wound closure in keratinocytes. Peptide-induced keratinocyte migration was mediated by purinergic receptors and metalloproteases. In contrast, SALPs did not affect proliferation of keratinocytes. Conclusively, our data suggest a novel therapeutic target for the treatment of patients with acute and chronic skin infections. PMID:27509895

The Effect of Traditional Chinese Formula Danchaiheji on the Differentiation of Regulatory Dendritic Cells

PubMed Central

Wang, Xiaodong; Tong, Jingzhi; Li, Keqiu; Jing, Yaqing

2016-01-01

Recently, regulatory dendritic cells (DCregs), a newly described dendritic cell subset with potent immunomodulatory function, have attracted increased attention for their utility in treating immune response-related diseases, such as graft-versus-host disease, hypersensitivity, and autoimmune diseases. Danchaiheji (DCHJ) is a traditional Chinese formula that has been used for many years in the clinic. However, whether DCHJ can program dendritic cells towards a regulatory phenotype and the underlying mechanism behind this process remain unknown. Herein, we investigate the effects of traditional Chinese DCHJ on DCregs differentiation and a mouse model of skin transplantation. The current study demonstrates that DCHJ can induce dendritic cells to differentiate into DCregs, which are represented by high CD11b and low CD86 and HLA-DR expression as well as the secretion of IL-10 and TGF-β. In addition, DCHJ inhibited DC migration and T cell proliferation, which correlated with increased IDO expression. Furthermore, DCHJ significantly prolonged skin graft survival time in a mouse model of skin transplantation without any liver or kidney toxicity. The traditional Chinese formula DCHJ has the potential to be a potent immunosuppressive agent with high efficiency and nontoxicity. PMID:27525028

Podosomes, But Not the Maturation Status, Determine the Protease-Dependent 3D Migration in Human Dendritic Cells.

PubMed

Cougoule, Céline; Lastrucci, Claire; Guiet, Romain; Mascarau, Rémi; Meunier, Etienne; Lugo-Villarino, Geanncarlo; Neyrolles, Olivier; Poincloux, Renaud; Maridonneau-Parini, Isabelle

2018-01-01

Dendritic cells (DC) are professional Antigen-Presenting Cells scattered throughout antigen-exposed tissues and draining lymph nodes, and survey the body for pathogens. Their ability to migrate through tissues, a 3D environment, is essential for an effective immune response. Upon infection, recognition of Pathogen-Associated Molecular Patterns (PAMP) by Toll-like receptors (TLR) triggers DC maturation. Mature DC (mDC) essentially use the protease-independent, ROCK-dependent amoeboid mode in vivo , or in collagen matrices in vitro . However, the mechanisms of 3D migration used by human immature DC (iDC) are still poorly characterized. Here, we reveal that human monocyte-derived DC are able to use two migration modes in 3D. In porous matrices of fibrillar collagen I, iDC adopted the amoeboid migration mode. In dense matrices of gelled collagen I or Matrigel, iDC used the protease-dependent, ROCK-independent mesenchymal migration mode. Upon TLR4 activation by LPS, mDC-LPS lose the capacity to form podosomes and degrade the matrix along with impaired mesenchymal migration. TLR2 activation by Pam 3 CSK 4 resulted in DC maturation, podosome maintenance, and efficient mesenchymal migration. Under all these conditions, when DC used the mesenchymal mode in dense matrices, they formed 3D podosomes at the tip of cell protrusions. Using PGE 2 , known to disrupt podosomes in DC, we observed that the cells remained in an immature status and the mesenchymal migration mode was abolished. We also observed that, while CCL5 (attractant of iDC) enhanced both amoeboid and mesenchymal migration of iDC, CCL19 and CCL21 (attractants of mDC) only enhanced mDC-LPS amoeboid migration without triggering mesenchymal migration. Finally, we examined the migration of iDC in tumor cell spheroids, a tissue-like 3D environment. We observed that iDC infiltrated spheroids of tumor cells using both migration modes. Altogether, these results demonstrate that human DC adopt the mesenchymal mode to migrate in 3D dense environments, which relies on their capacity to form podosomes independent of their maturation status, paving the way of further investigations on in vivo DC migration in dense tissues and its regulation during infections.

Oral Prion Disease Pathogenesis Is Impeded in the Specific Absence of CXCR5-Expressing Dendritic Cells

PubMed Central

Bradford, Barry M.; Reizis, Boris

2017-01-01

ABSTRACT After oral exposure, the early replication of certain prion strains upon stromal cell-derived follicular dendritic cells (FDC) in the Peyer's patches in the small intestine is essential for the efficient spread of disease to the brain. However, little is known of how prions are initially conveyed from the gut lumen to establish infection on FDC. Our previous data suggest that mononuclear phagocytes such as CD11c+ conventional dendritic cells play an important role in the initial propagation of prions from the gut lumen into Peyer's patches. However, whether these cells conveyed orally acquired prions toward FDC within Peyer's patches was not known. The chemokine CXCL13 is expressed by FDC and follicular stromal cells and modulates the homing of CXCR5-expressing cells toward the FDC-containing B cell follicles. Here, novel compound transgenic mice were created in which a CXCR5 deficiency was specifically restricted to CD11c+ cells. These mice were used to determine whether CXCR5-expressing conventional dendritic cells propagate prions toward FDC after oral exposure. Our data show that in the specific absence of CXCR5-expressing conventional dendritic cells the early accumulation of prions upon FDC in Peyer's patches and the spleen was impaired, and disease susceptibility significantly reduced. These data suggest that CXCR5-expressing conventional dendritic cells play an important role in the efficient propagation of orally administered prions toward FDC within Peyer's patches in order to establish host infection. IMPORTANCE Many natural prion diseases are acquired by oral consumption of contaminated food or pasture. Once the prions reach the brain they cause extensive neurodegeneration, which ultimately leads to death. In order for the prions to efficiently spread from the gut to the brain, they first replicate upon follicular dendritic cells within intestinal Peyer's patches. How the prions are first delivered to follicular dendritic cells to establish infection was unknown. Understanding this process is important since treatments which prevent prions from infecting follicular dendritic cells can block their spread to the brain. We created mice in which mobile conventional dendritic cells were unable to migrate toward follicular dendritic cells. In these mice the early accumulation of prions on follicular dendritic cells was impaired and oral prion disease susceptibility was reduced. This suggests that prions exploit conventional dendritic cells to facilitate their initial delivery toward follicular dendritic cells to establish host infection. PMID:28275192

GSK-3 signaling in developing cortical neurons is essential for radial migration and dendritic orientation.

PubMed

Morgan-Smith, Meghan; Wu, Yaohong; Zhu, Xiaoqin; Pringle, Julia; Snider, William D

2014-07-29

GSK-3 is an essential mediator of several signaling pathways that regulate cortical development. We therefore created conditional mouse mutants lacking both GSK-3α and GSK-3β in newly born cortical excitatory neurons. Gsk3-deleted neurons expressing upper layer markers exhibited striking migration failure in all areas of the cortex. Radial migration in hippocampus was similarly affected. In contrast, tangential migration was not grossly impaired after Gsk3 deletion in interneuron precursors. Gsk3-deleted neurons extended axons and developed dendritic arbors. However, the apical dendrite was frequently branched while basal dendrites exhibited abnormal orientation. GSK-3 regulation of migration in neurons was independent of Wnt/β-catenin signaling. Importantly, phosphorylation of the migration mediator, DCX, at ser327, and phosphorylation of the semaphorin signaling mediator, CRMP-2, at Thr514 were markedly decreased. Our data demonstrate that GSK-3 signaling is essential for radial migration and dendritic orientation and suggest that GSK-3 mediates these effects by phosphorylating key microtubule regulatory proteins.DOI: http://dx.doi.org/10.7554/eLife.02663.001. Copyright © 2014, Morgan-Smith et al.

Migration of Toxoplasma gondii–Infected Dendritic Cells across Human Retinal Vascular Endothelium

PubMed Central

Furtado, João M.; Bharadwaj, Arpita S.; Ashander, Liam M.; Olivas, Antoinette; Smith, Justine R.

2012-01-01

Purpose. Toxoplasma gondii, the parasite responsible for ocular toxoplasmosis, accesses the retina from the bloodstream. We investigated the dendritic cell as a potential taxi for T. gondii tachyzoites moving across the human retinal endothelium, and examined the participation of adhesion molecules and chemokines in this process. Methods. CD14-positive monocytes were isolated from human peripheral blood by antibody-mediated cell enrichment, and cultured in granulocyte-macrophage colony-stimulating factor and interleukin-4 to generate dendritic cells. Transmigration assays were performed over 18 hours in transwells seeded with human retinal endothelial cells and using dendritic cells exposed to laboratory or natural strains of T. gondii tachyzoites. Parasites were tagged with yellow fluorescent protein to verify infection. In some experiments, endothelial monolayers were preincubated with antibody directed against adhesion molecules, or chemokine was added to lower chambers of transwells. Results. Human monocyte–derived dendritic cell preparations infected with laboratory or natural strain T. gondii tachyzoites transmigrated in larger numbers across simulated human retinal endothelium than uninfected dendritic cells (P ≤ 0.0004 in 5 of 6 experiments). Antibody blockade of intercellular adhesion molecule (ICAM)–1, vascular cell adhesion molecule (VCAM)–1, and activated leukocyte cell adhesion molecule (ALCAM) inhibited transmigration (P ≤ 0.007), and CCL21 or CXCL10 increased transmigration (P ≤ 0.031). Conclusions. Transmigration of human dendritic cells across retinal endothelium is increased following infection with T. gondii. Movement may be impacted by locally produced chemokines and is mediated in part by ICAM-1, VCAM-1, and ALCAM. These findings have implications for development of novel therapeutics aimed at preventing retinal infection by T. gondii. PMID:22952125

Perinuclear Arp2/3-driven actin polymerization enables nuclear deformation to facilitate cell migration through complex environments

PubMed Central

Thiam, Hawa-Racine; Vargas, Pablo; Carpi, Nicolas; Crespo, Carolina Lage; Raab, Matthew; Terriac, Emmanuel; King, Megan C.; Jacobelli, Jordan; Alberts, Arthur S.; Stradal, Theresia; Lennon-Dumenil, Ana-Maria; Piel, Matthieu

2016-01-01

Cell migration has two opposite faces: although necessary for physiological processes such as immune responses, it can also have detrimental effects by enabling metastatic cells to invade new organs. In vivo, migration occurs in complex environments and often requires a high cellular deformability, a property limited by the cell nucleus. Here we show that dendritic cells, the sentinels of the immune system, possess a mechanism to pass through micrometric constrictions. This mechanism is based on a rapid Arp2/3-dependent actin nucleation around the nucleus that disrupts the nuclear lamina, the main structure limiting nuclear deformability. The cells' requirement for Arp2/3 to pass through constrictions can be relieved when nuclear stiffness is decreased by suppressing lamin A/C expression. We propose a new role for Arp2/3 in three-dimensional cell migration, allowing fast-moving cells such as leukocytes to rapidly and efficiently migrate through narrow gaps, a process probably important for their function. PMID:26975831

Epifluorescence Intravital Microscopy of Murine Corneal Dendritic Cells

PubMed Central

Rosenbaum, James T.; Planck, Stephen R.

2010-01-01

Purpose. Dendritic cells (DCs) are antigen-presenting cells vital for initiating immune responses. In this study the authors examined the in vivo migratory capability of resident corneal DCs to various stimuli. Methods. The authors used mice expressing enhanced yellow fluorescent protein (eYFP) under control of the CD11c promoter to visualize corneal DCs. To assess the distribution and mobility of DCs, normal corneas were imaged in vivo and ex vivo with fluorescence microscopy. Intravital microscopy was used to examine the responses of resident central and peripheral corneal DCs to silver nitrate injury, lipopolysaccharide, microspheres, and tumor necrosis factor (TNF-α). In some experiments, TNF-α injection was used to first induce centripetal migration of DCs to the central cornea, which was subsequently reinjected with microspheres. Results. In normal corneas, DCs were sparsely distributed centrally and were denser in the periphery, with epithelial-level DCs extending into the epithelium. Videomicroscopy showed that though cell processes were in continuous movement, cells generally did not migrate. Within the first 6 hours after stimulation, neither central nor peripheral corneal DCs exhibited significant lateral migration, but central corneal DCs assumed extreme morphologic changes. An increased number of DCs in the TNF-α–stimulated central cornea were responsive to subsequent microsphere injection by adopting a migratory behavior, but not with increased speed. Conclusions. In vivo imaging reveals minimal lateral migration of corneal DCs after various stimuli. In contrast, DCs within the central cornea after initial TNF-α injection are more likely to respond to a secondary insult with lateral migration. PMID:20007837

Phenotypic and functional analysis of CD1a+ dendritic cells from cats chronically infected with feline immunodeficiency virus.

PubMed

Zhang, Lin; Reckling, Stacie; Dean, Gregg A

2015-10-01

Numerous studies suggest dendritic cell (DC) dysfunction is central to the dysregulated immune response during HIV infection; however, in vivo studies are lacking. In the present study we used feline immunodeficiency virus (FIV) infection of cats as a model for HIV-1 infection to assess the maturation and function of dendritic cells, in vivo and in vitro. We compared CD1a+ DC migration, surface phenotype, endocytosis, mixed leukocyte reaction (MLR) and regulatory T cell (Treg) phenotype induction by CD1a+ cells isolated from lymph nodes of FIV-infected and control cats. Results showed that resident CD1a+ DC in lymph nodes of chronically FIV-infected cats are phenotypically mature, can stimulate normal primary T cell proliferation, override Treg suppression and do not skew toward Treg induction. In contrast, FIV infection had deleterious effects on antigen presentation and migratory capacity of CD1a+ cells in tissues. Copyright © 2015 Elsevier Ltd. All rights reserved.

Expression of CD73 slows down migration of skin dendritic cells, affecting the sensitization phase of contact hypersensitivity reactions in mice.

PubMed

Neuberger, A; Ring, S; Silva-Vilches, C; Schrader, J; Enk, A; Mahnke, K

2017-09-01

Application of haptens to the skin induces release of immune stimulatory ATP into the extracellular space. This "danger" signal can be converted to immunosuppressive adenosine (ADO) by the action of the ectonucleotidases CD39 and CD73, expressed by skin and immune cells. Thus, the expression and regulation of CD73 by skin derived cells may have crucial influence on the outcome of contact hypersensitivity (CHS) reactions. To investigate the role of CD73 expression during 2,4,6-trinitrochlorobenzene (TNCB) induced CHS reactions. Wild type (wt) and CD73 deficient mice were subjected to TNCB induced CHS. In the different mouse strains the resulting ear swelling reaction was recorded along with a detailed phenotypic analysis of the skin migrating subsets of dendritic cells (DC). In CD73 deficient animals the motility of DC was higher as compared to wt animals and in particular after sensitization we found increased migration of Langerin + DC from skin to draining lymph nodes (LN). In the TNCB model this led to a stronger sensitization as indicated by increased frequency of interferon-γ producing T cells in the LN and an increased ear thickness after challenge. CD73 derived ADO production slows down migration of Langerin + DC from skin to LN. This may be a crucial mechanism to avoid over boarding immune reactions against haptens. Copyright © 2017 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.

Human cytomegalovirus alters localization of MHC class II and dendrite morphology in mature Langerhans cells.

PubMed

Lee, Andrew W; Hertel, Laura; Louie, Ryan K; Burster, Timo; Lacaille, Vashti; Pashine, Achal; Abate, Davide A; Mocarski, Edward S; Mellins, Elizabeth D

2006-09-15

Hemopoietic stem cell-derived mature Langerhans-type dendritic cells (LC) are susceptible to productive infection by human CMV (HCMV). To investigate the impact of infection on this cell type, we examined HLA-DR biosynthesis and trafficking in mature LC cultures exposed to HCMV. We found decreased surface HLA-DR levels in viral Ag-positive as well as in Ag-negative mature LC. Inhibition of HLA-DR was independent of expression of unique short US2-US11 region gene products by HCMV. Indeed, exposure to UV-inactivated virus, but not to conditioned medium from infected cells, was sufficient to reduce HLA-DR on mature LC, implicating particle binding/penetration in this effect. Reduced surface levels reflected an altered distribution of HLA-DR because total cellular HLA-DR was not diminished. Accumulation of HLA-DR was not explained by altered cathepsin S activity. Mature, peptide-loaded HLA-DR molecules were retained within cells, as assessed by the proportion of SDS-stable HLA-DR dimers. A block in egress was implicated, as endocytosis of surface HLA-DR was not increased. Immunofluorescence microscopy corroborated the intracellular retention of HLA-DR and revealed markedly fewer HLA-DR-positive dendritic projections in infected mature LC. Unexpectedly, light microscopic analyses showed a dramatic loss of the dendrites themselves and immunofluorescence revealed that cytoskeletal elements crucial for the formation and maintenance of dendrites are disrupted in viral Ag-positive cells. Consistent with these dendrite effects, HCMV-infected mature LC exhibit markedly reduced chemotaxis in response to lymphoid chemokines. Thus, HCMV impedes MHC class II molecule trafficking, dendritic projections, and migration of mature LC. These changes likely contribute to the reduced activation of CD4+ T cells by HCMV-infected mature LC.

Regulatory role of periodontal ligament fibroblasts for innate immune cell function and differentiation.

PubMed

Konermann, Anna; Stabenow, Dirk; Knolle, Percy A; Held, Stefanie A E; Deschner, James; Jäger, Andreas

2012-10-01

Innate immunity is crucial for an effective host defense against pathogenic microorganisms in periodontal tissues. As periodontal ligament (PDL) cells synthesize immunomodulatory cytokines, the aim of this in vitro study was to investigate whether these cells can interact with innate immune cells. Resting and inflammatory primed (IL-1β, TNF-α, HMGB1) human PDL cells were co-cultured with human monocyte-derived dendritic cells or macrophages. Migration, phenotypic maturation and modulation of phagocytosis of Porphyromonas gingivalis by immune cells were investigated upon co-culture with PDL cells and/or their released soluble factors. PDL cells interacted with immune cells under both non-inflammatory and inflammatory conditions. Immune cell migration was significantly enhanced by co-culture with PDL cells, which also affected their phenotypic maturation both through cell-cell contact and through released soluble mediators. The dendritic cell maturation markers CD83 and CD86 were upregulated as much as both 'alternatively activated' M2 macrophage maturation markers CD23 and CD163. In contrast, the 'classically activated' M1 macrophage maturation marker CD64 was downregulated. Finally, PDL cells significantly enhanced the phagocytosis of Porphyromonas gingivalis by immune cells. Our experiments revealed that PDL cells are not only structural elements of the periodontium, but actively influence immune responses by interaction with innate immune cells.

EBI1/CCR7 is a new member of dendritic cell chemokine receptor that is up-regulated upon maturation.

PubMed

Yanagihara, S; Komura, E; Nagafune, J; Watarai, H; Yamaguchi, Y

1998-09-15

Dendritic cells (DC) that are stimulated with inflammatory mediators can maturate and migrate from nonlymphoid tissues to lymphoid organs to initiate T cell-mediated immune responses. This migratory step is closely related to the maturation of the DC. In an attempt to identify chemokine receptors that might influence migration and are selectively expressed in mature DC, we have discovered that the chemokine receptor, EBI1/CCR7, is strikingly up-regulated upon maturation in three distinct culture systems: 1) mouse bone marrow-derived DC, 2) mouse epidermal Langerhans cells, and 3) human monocyte-derived DC. The EBI1/CCR7 expressed in mature DC is functional because ELC/MIP-3beta, recently identified as a ligand of EBI1/CCR7, induces a rise in intracellular free calcium concentrations and directional migration of human monocyte-derived mature DC (HLA-DRhigh, CD1a(low), CD14-, CD25+, CD83+, and CD86high) in a dose-dependent manner, but not of immature DC (HLA-DRlow, CD1a(high), CD14-, CD25-, CD83-, and CD86-). In contrast, macrophage inflammatory protein-1alpha (MIP-1alpha), monocyte chemotactic protein-3 (MCP-3), and RANTES are active on immature DC but not on mature DC. Thus, it seems likely that MIP-1alpha, MCP-3, and RANTES can mediate the migration of immature DC located in peripheral sites, whereas ELC/MIP-3beta can direct the migration of Ag-carrying DC from peripheral inflammatory sites, where DC are stimulated to up-regulate the expression of EBI1/CCR7, to lymphoid organs. It is postulated that different chemokines and chemokine receptors are involved in DC migration in vivo, depending on the maturation state of DC.

NK cells are necessary for recovery of corneal CD11c+ dendritic cells after epithelial abrasion injury

USDA-ARS?s Scientific Manuscript database

Mechanisms controlling CD11c(+) MHCII(+) DCs during corneal epithelial wound healing were investigated in a murine model of corneal abrasion. Selective depletion of NKp46(+) CD3- NK cells that normally migrate into the cornea after epithelial abrasion resulted in >85% reduction of the epithelial CD1...

Transduction of skin-migrating dendritic cells by human adenovirus 5 occurs via an actin-dependent phagocytic pathway.

PubMed

Guzman, Efrain; Taylor, Geraldine; Hope, Jayne; Herbert, Rebecca; Cubillos-Zapata, Carolina; Charleston, Bryan

2016-10-01

Dendritic cells (DC) are central to the initiation of immune responses, and various approaches have been used to target vaccines to DC in order to improve immunogenicity. Cannulation of lymphatic vessels allows for the collection of DC that migrate from the skin. These migrating DC are involved in antigen uptake and presentation following vaccination. Human replication-deficient adenovirus (AdV) 5 is a promising vaccine vector for delivery of recombinant antigens. Although the mechanism of AdV attachment and penetration has been extensively studied in permissive cell lines, few studies have addressed the interaction of AdV with DC. In this study, we investigated the interaction of bovine skin-migrating DC and replication-deficient AdV-based vaccine vectors. We found that, despite lack of expression of Coxsackie B-Adenovirus Receptor and other known adenovirus receptors, AdV readily enters skin-draining DC via an actin-dependent endocytosis. Virus exit from endosomes was pH independent, and neutralizing antibodies did not prevent virus entry but did prevent virus translocation to the nucleus. We also show that combining adenovirus with adjuvant increases the absolute number of intracellular virus particles per DC but not the number of DC containing intracellular virus. This results in increased trans-gene expression and antigen presentation. We propose that, in the absence of Coxsackie B-Adenovirus Receptor and other known receptors, AdV5-based vectors enter skin-migrating DC using actin-dependent endocytosis which occurs in skin-migrating DC, and its relevance to vaccination strategies and vaccine vector targeting is discussed.

AMP Affects Intracellular Ca2+ Signaling, Migration, Cytokine Secretion and T Cell Priming Capacity of Dendritic Cells

PubMed Central

Panther, Elisabeth; Dürk, Thorsten; Ferrari, Davide; Di Virgilio, Francesco; Grimm, Melanie; Sorichter, Stephan; Cicko, Sanja; Herouy, Yared; Norgauer, Johannes; Idzko, Marco; Müller, Tobias

2012-01-01

The nucleotide adenosine-5′-monophosphate (AMP) can be released by various cell types and has been shown to elicit different cellular responses. In the extracellular space AMP is dephosphorylated to the nucleoside adenosine which can then bind to adenosine receptors. However, it has been shown that AMP can also activate A1 and A2a receptors directly. Here we show that AMP is a potent modulator of mouse and human dendritic cell (DC) function. AMP increased intracellular Ca2+ concentration in a time and dose dependent manner. Furthermore, AMP stimulated actin-polymerization in human DCs and induced migration of immature human and bone marrow derived mouse DCs, both via direct activation of A1 receptors. AMP strongly inhibited secretion of TNF-α and IL-12p70, while it enhanced production of IL-10 both via activation of A2a receptors. Consequently, DCs matured in the presence of AMP and co-cultivated with naive CD4+CD45RA+ T cells inhibited IFN-γ production whereas secretion of IL-5 and IL-13 was up-regulated. An enhancement of Th2-driven immune response could also be observed when OVA-pulsed murine DCs were pretreated with AMP prior to co-culture with OVA-transgenic naïve OTII T cells. An effect due to the enzymatic degradation of AMP to adenosine could be ruled out, as AMP still elicited migration and changes in cytokine secretion in bone-marrow derived DCs generated from CD73-deficient animals and in human DCs pretreated with the ecto-nucleotidase inhibitor 5′-(alpha,beta-methylene) diphosphate (APCP). Finally, the influence of contaminating adenosine could be excluded, as AMP admixed with adenosine desaminase (ADA) was still able to influence DC function. In summary our data show that AMP when present during maturation is a potent regulator of dendritic cell function and point out the role for AMP in the pathogenesis of inflammatory disorders. PMID:22624049

Impact of tobacco smoke on upper airway dendritic cell accumulation and regulation by sinonasal epithelial cells.

PubMed

Mulligan, Jennifer K; O'Connell, Brendan P; Pasquini, Whitney; Mulligan, Ryan M; Smith, Sarah; Soler, Zachary M; Atkinson, Carl; Schlosser, Rodney J

2017-08-01

In these studies we examined the impact of environmental tobacco smoke (ETS) and active smoking on sinonasal dendritic cell (DC) subsets in controls or patients with chronic rhinosinusitis with nasal polyps (CRSwNP). In subsequent in-vitro investigations, we examined the influence of cigarette smoke extract (CSE) on human sinonasal epithelial cells' (HSNECs) ability to regulate DC functions. Sinonasal tissue, blood, and hair were collected from patients undergoing sinus surgery. Smoking status and ETS exposure were determined by hair nicotine. DC subsets were examined by flow cytometric analysis. Monocyte-derived dendritic cells (moDCs) were treated with conditioned medium from non-smoked-exposed HSNECs (NS-HSNECs) or cigarette-smoke-extract-exposed HSNECs (CSE-HSNECs) to assess the impact of CSE exposure on HSNEC regulation of moDC functions. Control subjects who were active smokers displayed increased sinonasal moDC and myeloid dendritic 1 (mDC1) cells and reduced mDC2 cells, whereas, in CRSwNP patients, only moDC and mDC2 cells were altered. ETS was found to increase only moDCs in the CRSwNP patients. In vitro, CSE stimulated HSNEC secretion of the moDC regulatory products chemokine (C-C motif) ligand 20, prostaglandin E 2 , and granulocyte-macrophage colony-stimulating factor. CSE exposure also promoted HSNECs to stimulate monocyte and moDC migration. moDCs treated with CSE-HSNEC media stimulated an increase in antigen uptake and expression of CD80 and CD86. Last, CSE-HSNEC-treated moDCs secreted increased levels of interleukin-10, interferon-γ, and thymic stromal lymphopoietin. Active smoking, and to a lesser degree ETS, alters the sinonasal composition of DCs. A potential mechanism to account for this is that cigarette smoke stimulates HSNECs to induce moDC migration, maturation, and activation. © 2017 ARS-AAOA, LLC.

Apigenin inhibits proliferation and invasion, and induces apoptosis and cell cycle arrest in human melanoma cells.

PubMed

Zhao, Guangming; Han, Xiaodong; Cheng, Wei; Ni, Jing; Zhang, Yunfei; Lin, Jingrong; Song, Zhiqi

2017-04-01

Malignant melanoma is the most invasive and fatal form of cutaneous cancer. Moreover it is extremely resistant to conventional chemotherapy and radiotherapy. Apigenin, a non-mutagenic flavonoid, has been found to exhibit chemopreventive and/or anticancerogenic properties in many different types of human cancer cells. Therefore, apigenin may have particular relevance for development as a chemotherapeutic agent for cancer treatment. In the present study, we investigated the effects of apigenin on the viability, migration and invasion potential, dendrite morphology, cell cycle distribution, apoptosis, phosphorylation of the extracellular signal-regulated protein kinase (ERK) and the AKT/mTOR signaling pathway in human melanoma A375 and C8161 cell lines in vitro. Apigenin effectively suppressed the proliferation of melanoma cells in vitro. Moreover, it inhibited cell migration and invasion, lengthened the dendrites, and induced G2/M phase arrest and apoptosis. Furthermore, apigenin promoted the activation of cleaved caspase-3 and cleaved PARP proteins and decreased the expression of phosphorylated (p)‑ERK1/2 proteins, p-AKT and p-mTOR. Consequently, apigenin is a novel therapeutic candidate for melanoma.

Fine-tuned SRF activity controls asymmetrical neuronal outgrowth: implications for cortical migration, neural tissue lamination and circuit assembly

PubMed Central

Scandaglia, Marilyn; Benito, Eva; Morenilla-Palao, Cruz; Fiorenza, Anna; del Blanco, Beatriz; Coca, Yaiza; Herrera, Eloísa; Barco, Angel

2015-01-01

The stimulus-regulated transcription factor Serum Response Factor (SRF) plays an important role in diverse neurodevelopmental processes related to structural plasticity and motile functions, although its precise mechanism of action has not yet been established. To further define the role of SRF in neural development and distinguish between cell-autonomous and non cell-autonomous effects, we bidirectionally manipulated SRF activity through gene transduction assays that allow the visualization of individual neurons and their comparison with neighboring control cells. In vitro assays showed that SRF promotes survival and filopodia formation and is required for normal asymmetric neurite outgrowth, indicating that its activation favors dendrite enlargement versus branching. In turn, in vivo experiments demonstrated that SRF-dependent regulation of neuronal morphology has important consequences in the developing cortex and retina, affecting neuronal migration, dendritic and axonal arborization and cell positioning in these laminated tissues. Overall, our results show that the controlled and timely activation of SRF is essential for the coordinated growth of neuronal processes, suggesting that this event regulates the switch between neuronal growth and branching during developmental processes. PMID:26638868

Modulating glioma-mediated myeloid-derived suppressor cell development with sulforaphane

PubMed Central

Kumar, Ravi; de Mooij, Tristan; Peterson, Timothy E.; Kaptzan, Tatiana; Johnson, Aaron J.; Daniels, David J.; Parney, Ian F.

2017-01-01

Glioblastoma is the most common primary tumor of the brain and has few long-term survivors. The local and systemic immunosuppressive environment created by glioblastoma allows it to evade immunosurveillance. Myeloid-derived suppressor cells (MDSCs) are a critical component of this immunosuppression. Understanding mechanisms of MDSC formation and function are key to developing effective immunotherapies. In this study, we developed a novel model to reliably generate human MDSCs from healthy-donor CD14+ monocytes by culture in human glioma-conditioned media. Monocytic MDSC frequency was assessed by flow cytometry and confocal microscopy. The resulting MDSCs robustly inhibited T cell proliferation. A cytokine array identified multiple components of the GCM potentially contributing to MDSC generation, including Monocyte Chemoattractive Protein-1, interleukin-6, interleukin-8, and Macrophage Migration Inhibitory Factor (MIF). Of these, Macrophage Migration Inhibitory Factor is a particularly attractive therapeutic target as sulforaphane, a naturally occurring MIF inhibitor derived from broccoli sprouts, has excellent oral bioavailability. Sulforaphane inhibits the transformation of normal monocytes to MDSCs by glioma-conditioned media in vitro at pharmacologically relevant concentrations that are non-toxic to normal leukocytes. This is associated with a corresponding increase in mature dendritic cells. Interestingly, sulforaphane treatment had similar pro-inflammatory effects on normal monocytes in fresh media but specifically increased immature dendritic cells. Thus, we have used a simple in vitro model system to identify a novel contributor to glioblastoma immunosuppression for which a natural inhibitor exists that increases mature dendritic cell development at the expense of myeloid-derived suppressor cells when normal monocytes are exposed to glioma conditioned media. PMID:28666020

Involvement of dendritic cells in allograft rejection new implications of dendritic cell-endothelial cell interactions.

PubMed

Schlichting, C L; Schareck, W D; Kofler, S; Weis, M

2007-04-01

For almost half a century immunologists have tried to tear down the MHC barrier, which separates two unrelated individuals during transplantation. Latest experimental data suggest that a breakthrough in vitro is imminent. Dendritic cells (DCs), which activate naïve allo-reactive T-cells (TCs), play a central role in the establishment of allo-antigen-specific immunity. Allograft solid organ rejection is initiated at the foreign endothelial cell (EC) layer, which forms an immunogenic barrier for migrating DCs. Thus, DC/EC interactions might play a crucial role in antigen-specific allograft rejection. Organ rejection is mediated by host allo-reactive TCs, which are activated by donor DCs (direct activation) or host DCs (indirect activation). Direct allo-antigen presentation by regulatory dendritic cells (DCreg) can play an instructive role towards tolerance induction. Several groups established that, DCregs, if transplanted beforehand, enter host thymus, spleen, or bone marrow where they might eventually establish allo-antigen-specific tolerance. A fundamental aspect of DC function is migration throughout the entire organism. After solid organ transplantation, host DCs bind to ECs, invade allograft tissues, and finally transmigrate into lymphoid vessels and secondary lymphoid organs, where they present allo-antigens to naïve host TCs. Recent data suggest that in vitro manipulated DCregs may mediate allo-transplantation tolerance induction. However, the fundamental mechanisms on how such DCregs cause host TCs in the periphery towards tolerance remain unclear. One very promising experimental concept is the simultaneous manipulation of DC direct and indirect TC activation/suppression, towards donor antigen-specific allo-transplantation tolerance. The allo-antigen-specific long-term tolerance induction mediated by DCreg pre-transplantation (with simultaneous short-term immunosuppression) has become reproducible in the laboratory animal setting. Despite the shortcomings of laboratory animal studies, strong promises are deriving from these studies for clinical kidney, heart, and liver transplantation.

Concurrent CCR7 Overexpression and RelB Knockdown in Immature Dendritic Cells Induces Immune Tolerance and Improves Skin-Graft Survival in a Murine Model.

PubMed

Dong, Zhiwei; Chen, Yajie; Peng, Yuan; Wang, Fan; Yang, Zichen; Huang, Guangtao; Chen, Yu; Yuan, Zhiqiang; Cao, Tongtong; Peng, Yizhi

2017-01-01

Skin transplantation aims to cover skin defects but often fails due to immune rejection of the transplantated tissue. Immature dendritic cells (imDCs) induce immune tolerance but have a low migration rate. After stimulation, imDCs transform into mature DCs, which activate immune rejection. Thus, inducing imDC to obtain a high migration counteracts development of immune tolerance. We transfected imDCs with a recombinant adenovirus carrying the CCR7 gene (Ad-CCR7) and a small interfering RNA targeting RelB (RelB-siRNA) to concurrently overexpress CCR7 and downregulate RelB expression. Functionally, such cells showed a significantly enhanced migration rate in the chemotactic assay and decreased T-cell proliferation after lipopolysaccharide stimulation in mixed lymphocyte reactions. Cotransfected cells showed an increased ability to induce immune tolerance by upregulating T regulatory (Treg) cells and shifting the Th1/Th2 ratio. Cotransfection of Ad-CCR7 and RelB-siRNA endowed imDCs with resistance to apoptosis and cell death. CCR7 overexpression and RelB knockdown (KD) in imDCs improve skin-graft survival in a murine skin-transplantation model. Transfection with Ad-CCR7 and RelB KD in imDCs may be an effective approach inducing immune tolerance, thus being potentially valuable for inhibiting allograft rejection. © 2017 The Author(s). Published by S. Karger AG, Basel.

Desirable cytolytic immune effector cell recruitment by interleukin-15 dendritic cells.

PubMed

Van Acker, Heleen H; Beretta, Ottavio; Anguille, Sébastien; De Caluwé, Lien; Papagna, Angela; Van den Bergh, Johan M; Willemen, Yannick; Goossens, Herman; Berneman, Zwi N; Van Tendeloo, Viggo F; Smits, Evelien L; Foti, Maria; Lion, Eva

2017-02-21

Success of dendritic cell (DC) therapy in treating malignancies is depending on the DC capacity to attract immune effector cells, considering their reciprocal crosstalk is partially regulated by cell-contact-dependent mechanisms. Although critical for therapeutic efficacy, immune cell recruitment is a largely overlooked aspect regarding optimization of DC vaccination. In this paper we have made a head-to-head comparison of interleukin (IL)-15-cultured DCs and conventional IL-4-cultured DCs with regard to their proficiency in the recruitment of (innate) immune effector cells. Here, we demonstrate that IL-4 DCs are suboptimal in attracting effector lymphocytes, while IL15 DCs provide a favorable chemokine milieu for recruiting CD8+ T cells, natural killer (NK) cells and gamma delta (γδ) T cells. Gene expression analysis revealed that IL-15 DCs exhibit a high expression of chemokines involved in antitumor immune effector cell attraction, while IL-4 DCs display a more immunoregulatory profile characterized by the expression of Th2 and regulatory T cell-attracting chemokines. This is confirmed by functional data indicating an enhanced recruitment of granzyme B+ effector lymphocytes by IL-15 DCs, as compared to IL-4 DCs, and subsequent superior killing of tumor cells by the migrated lymphocytes. Elevated CCL4 gene expression in IL-15 DCs and lowered CCR5 expression on both migrated γδ T cells and NK cells, led to validation of increased CCL4 secretion by IL15 DCs. Moreover, neutralization of CCR5 prior to migration resulted in an important inhibition of γδ T cell and NK cell recruitment by IL-15 DCs. These findings further underscore the strong immunotherapeutic potential of IL-15 DCs.

Active Shaping of Chemokine Gradients by Atypical Chemokine Receptors: A 4D Live-Cell Imaging Migration Assay.

PubMed

Werth, Kathrin; Förster, Reinhold

2016-01-01

Diffusion of chemokines away from their site of production results in the passive formation of chemokine gradients. We have recently shown that chemokine gradients can also be formed in an active manner, namely by atypical chemokine receptors (ACKRs) that scavenge chemokines locally. Here, we describe an advanced method that allows the visualization of leukocyte migration in a three-dimensional environment along a chemokine gradient that is actively established by cells expressing an ACKR. Initially developed to visualize the migration of dendritic cells along gradients of CCL19 or CCL21 that were actively shaped by an ACKR4-expressing cell line, we expect that this chamber system can be exploited to study many other combinations of atypical and conventional chemokine receptor-expressing cells. © 2016 Elsevier Inc. All rights reserved.

Migrating Myeloid Cells Sense Temporal Dynamics of Chemoattractant Concentrations.

PubMed

Petrie Aronin, Caren E; Zhao, Yun M; Yoon, Justine S; Morgan, Nicole Y; Prüstel, Thorsten; Germain, Ronald N; Meier-Schellersheim, Martin

2017-11-21

Chemoattractant-mediated recruitment of hematopoietic cells to sites of pathogen growth or tissue damage is critical to host defense and organ homeostasis. Chemotaxis is typically considered to rely on spatial sensing, with cells following concentration gradients as long as these are present. Utilizing a microfluidic approach, we found that stable gradients of intermediate chemokines (CCL19 and CXCL12) failed to promote persistent directional migration of dendritic cells or neutrophils. Instead, rising chemokine concentrations were needed, implying that temporal sensing mechanisms controlled prolonged responses to these ligands. This behavior was found to depend on G-coupled receptor kinase-mediated negative regulation of receptor signaling and contrasted with responses to an end agonist chemoattractant (C5a), for which a stable gradient led to persistent migration. These findings identify temporal sensing as a key requirement for long-range myeloid cell migration to intermediate chemokines and provide insights into the mechanisms controlling immune cell motility in complex tissue environments. Published by Elsevier Inc.

R5 HIV-1 envelope attracts dendritic cells to cross the human intestinal epithelium and sample luminal virions via engagement of the CCR5

PubMed Central

Cavarelli, Mariangela; Foglieni, Chiara; Rescigno, Maria; Scarlatti, Gabriella

2013-01-01

The gastrointestinal tract is a principal route of entry and site of persistence of human immunodeficiency virus type 1 (HIV-1). The intestinal mucosa, being rich of cells that are the main target of the virus, represents a primary site of viral replication and CD4+ T-cell depletion. Here, we show both in vitro and ex vivo that HIV-1 of R5 but not X4 phenotype is capable of selectively triggering dendritic cells (DCs) to migrate within 30 min between intestinal epithelial cells to sample virions and transfer infection to target cells. The engagement of the chemokine receptor 5 on DCs and the viral envelope, regardless of the genetic subtype, drive DC migration. Viruses penetrating through transient opening of the tight junctions likely create a paracellular gradient to attract DCs. The formation of junctions with epithelial cells may initiate a haptotactic process of DCs and at the same time favour cell-to-cell viral transmission. Our findings indicate that HIV-1 translocation across the intestinal mucosa occurs through the selective engagement of DCs by R5 viruses, and may guide the design of new prevention strategies. PMID:23606583

R5 HIV-1 envelope attracts dendritic cells to cross the human intestinal epithelium and sample luminal virions via engagement of the CCR5.

PubMed

Cavarelli, Mariangela; Foglieni, Chiara; Rescigno, Maria; Scarlatti, Gabriella

2013-05-01

The gastrointestinal tract is a principal route of entry and site of persistence of human immunodeficiency virus type 1 (HIV-1). The intestinal mucosa, being rich of cells that are the main target of the virus, represents a primary site of viral replication and CD4(+) T-cell depletion. Here, we show both in vitro and ex vivo that HIV-1 of R5 but not X4 phenotype is capable of selectively triggering dendritic cells (DCs) to migrate within 30 min between intestinal epithelial cells to sample virions and transfer infection to target cells. The engagement of the chemokine receptor 5 on DCs and the viral envelope, regardless of the genetic subtype, drive DC migration. Viruses penetrating through transient opening of the tight junctions likely create a paracellular gradient to attract DCs. The formation of junctions with epithelial cells may initiate a haptotactic process of DCs and at the same time favour cell-to-cell viral transmission. Our findings indicate that HIV-1 translocation across the intestinal mucosa occurs through the selective engagement of DCs by R5 viruses, and may guide the design of new prevention strategies. Copyright © 2013 The Authors. Published by John Wiley and Sons, Ltd on behalf of EMBO.

Dendritic cells in oral tolerance in the gut.

PubMed

Rescigno, Maria

2011-09-01

Oral tolerance is a process that allows generation of systemic unresponsiveness to food antigens. Hence if the same antigen is introduced systemically even under immunogenic conditions it does not induce immune responsiveness. Dendritic cells (DCs) have been identified as essential players in this process. DCs in the gut are located in a strategic position as they can interact directly with luminal antigens or indirectly after their transcytosis across epithelial cells. DCs can then migrate to associated lymphoid tissues to induce tolerance. Antigen presenting cells in the gut are specialized in function and have divided their labour so that there are cells capable to migrate to the draining mesenteric lymph node for induction of T regulatory cells, while other subsets are resident and are required to enforce tolerance locally in the gut after food antigen exposure. In this review, I shall summarize the characteristics of antigen presenting cells in the gut and their involvement in oral tolerance induction. In addition, I will also emphasize that tolerance to food allergens may be contributed by plasmacytoid DCs in the liver that participate to the elimination or anergy of allergen-specific CD8 T cells. Hence specialized functions are associated to different subsets of antigen presenting cells and different organs. © 2011 Blackwell Publishing Ltd.

Genetic Dissection of Dendritic Cell Homeostasis and Function: Lessons from Cell Type–Specific Gene Ablation

PubMed Central

Karmaus, Peer W.F.; Chi, Hongbo

2014-01-01

Dendritic cells (DCs) are a heterogeneous cell population of great importance in the immune system. The emergence of new genetic technology utilizing the CD11c promoter and Cre recombinase has facilitated the dissection of functional significance and molecular regulation of DCs in immune responses and homeostasis in vivo. For the first time, this strategy allows observation of the effects of DC-specific gene deletion on immune system function in an intact organism. In this review, we present the latest findings from studies using the Cre recombinase system for cell type–specific deletion of key molecules that mediate DC homeostasis and function. Our focus is on the molecular pathways that orchestrate DC life span, migration, antigen presentation, pattern recognition, and cytokine production and signaling. PMID:24366237

TLR4-mediated podosome loss discriminates gram-negative from gram-positive bacteria in their capacity to induce dendritic cell migration and maturation.

PubMed

van Helden, Suzanne F G; van den Dries, Koen; Oud, Machteld M; Raymakers, Reinier A P; Netea, Mihai G; van Leeuwen, Frank N; Figdor, Carl G

2010-02-01

Chronic infections are caused by microorganisms that display effective immune evasion mechanisms. Dendritic cell (DC)-dependent T cell-mediated adaptive immunity is one of the mechanisms that have evolved to prevent the occurrence of chronic bacterial infections. In turn, bacterial pathogens have developed strategies to evade immune recognition. In this study, we show that gram-negative and gram-positive bacteria differ in their ability to activate DCs and that gram-negative bacteria are far more effective inducers of DC maturation. Moreover, we observed that only gram-negative bacteria can induce loss of adhesive podosome structures in DCs, a response necessary for the induction of effective DC migration. We demonstrate that the ability of gram-negative bacteria to trigger podosome turnover and induce DC migration reflects their capacity to selectively activate TLR4. Examining mice defective in TLR4 signaling, we show that this DC maturation and migration are mainly Toll/IL-1 receptor domain-containing adaptor-inducing IFNbeta-dependent. Furthermore, we show that these processes depend on the production of PGs by these DCs, suggesting a direct link between TLR4-mediated signaling and arachidonic metabolism. These findings demonstrate that gram-positive and gram-negative bacteria profoundly differ in their capacity to activate DCs. We propose that this inability of gram-positive bacteria to induce DC maturation and migration is part of the armamentarium necessary for avoiding the induction of an effective cellular immune response and may explain the frequent involvement of these pathogens in chronic infections.

Regulation of Polysaccharide- and Protein- Specific Antibody Responses to Intact Extracellular Bacteria

DTIC Science & Technology

2016-03-11

50, Immunology. 26 | P a g e blood-borne antigens. The white pulp consists of the periarteriolar lymphoid sheath (PALS) which contain T cells ...and CD8α+ dendritic (DC), and adjacent lymphoid follicles containing mainly circulating B cells , known as follicular B cells (FB). The outer boundary...complexes, for initial priming within the T cell zones of secondary lymphoid organs followed by migration of T cells to the T cell -B cell border. B

Regulatory T cell effects in antitumor laser immunotherapy: a mathematical model and analysis

NASA Astrophysics Data System (ADS)

Dawkins, Bryan A.; Laverty, Sean M.

2016-03-01

Regulatory T cells (Tregs) have tremendous influence on treatment outcomes in patients receiving immunotherapy for cancerous tumors. We present a mathematical model incorporating the primary cellular and molecular components of antitumor laser immunotherapy. We explicitly model developmental classes of dendritic cells (DCs), cytotoxic T cells (CTLs), primary and metastatic tumor cells, and tumor antigen. Regulatory T cells have been shown to kill antigen presenting cells, to influence dendritic cell maturation and migration, to kill activated killer CTLs in the tumor microenvironment, and to influence CTL proliferation. Since Tregs affect explicitly modeled cells, but we do not explicitly model dynamics of Treg themselves, we use model parameters to analyze effects of Treg immunosuppressive activity. We will outline a systematic method for assigning clinical outcomes to model simulations and use this condition to associate simulated patient treatment outcome with Treg activity.

Monocyte-derived dendritic cells induce a house dust mite-specific Th2 allergic inflammation in the lung of humanized SCID mice: involvement of CCR7.

PubMed

Hammad, Hamida; Lambrecht, Bart N; Pochard, Pierre; Gosset, Philippe; Marquillies, Philippe; Tonnel, André-Bernard; Pestel, Joël

2002-08-01

In rodents, airway dendritic cells (DCs) capture inhaled Ag, undergo maturation, and migrate to the draining mediastinal lymph nodes (MLN) to initiate the Ag-specific T cell response. However, the role of human DCs in the pathogenesis of the Th2 cell-mediated disease asthma remains to be clarified. Here, by using SCID mice engrafted with T cells from either house dust mite (HDM)-allergic patients or healthy donors, we show that DCs pulsed with Der p 1, one of the major allergens of HDM, and injected intratracheally into naive animals migrated into the MLN. In the MLN, Der p 1-pulsed DCs from allergic patients induced the proliferation of IL-4-producing CD4(+) T cells, whereas those from healthy donors induced IFN-gamma-secreting cells. In reconstituted human PBMC-reconstituted SCID mice primed with pulsed DCs from allergic patients, repeated exposure to aerosols of HDM induced 1) a strong pulmonary inflammatory reaction rich in T cells and eosinophils, 2) an increase in IL-4 and IL-5 production in the lung lavage fluid, and 3) increased IgE production compared with that in mice primed with unpulsed DCs. All these effects were reduced following in vivo neutralization of the CCR7 ligand secondary lymphoid tissue chemokine. These data in human PBMC-reconstituted SCID mice show that monocyte-derived DCs might play a key role in the pathogenesis of the pulmonary allergic response by inducing Th2 effector function following migration to the MLN.

Tumor exosomes block dendritic cells maturation to decrease the T cell immune response.

PubMed

Ning, Yongling; Shen, Kai; Wu, Qiyong; Sun, Xiao; Bai, Yu; Xie, Yewen; Pan, Jie; Qi, Chunjian

2018-07-01

Tumors can induce the generation and accumulation of immunosuppression in a tumor microenvironment, contributing to the tumor's escape from immunological surveillance. Although tumor antigen-pulsed dendritic cell can improve anti-tumor immune responses, tumor associated regulatory dendritic cells are involved in the induction of immune tolerance. The current study sought to investigate whether exosomes produced by tumor cells had any effect on DCs in immune suppression. In this study, we examined the effect of tumor exosomes on DCs and found that exosomes from LLC Lewis lung carcinoma or 4T1 breast cancer cell blocked the differentiation of myeloid precursor cells into CD11c + DCs and induced cell apoptosis. Tumor exosome treatment inhibited the maturation and migration of DCs and promoted the immune suppression of DCs. The treatment of tumor exosomes drastically decreased CD4 + IFN-γ + Th1 differentiation but increased the rates of regulatory T (Treg) cells. The immunosuppressive ability of tumor exosome-treated DCs were partially restored with PD-L1 blockage. These data suggested that PD-L1 played a role in tumor exosome-induced DC-associated immune suppression. Copyright © 2018 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.

Discordance in the effects of Yersinia pestis on the dendritic cell functions manifested by induction of maturation and paralysis of migration.

PubMed

Velan, Baruch; Bar-Haim, Erez; Zauberman, Ayelet; Mamroud, Emanuelle; Shafferman, Avigdor; Cohen, Sara

2006-11-01

The encounter between invading microorganisms and dendritic cells (DC) triggers a series of events which include uptake and degradation of the microorganism, induction of a maturation process, and enhancement of DC migration to the draining lymph nodes. Various pathogens have developed strategies to counteract these events as a measure to evade the host defense. In the present study we found that interaction of the Yersinia pestis EV76 strain with DC has no effect on cell viability and is characterized by compliance with effective maturation, which is manifested by surface display of major histocompatibility complex class II, of costimulatory markers, and of the chemokine receptor CCR7. This is in contrast to maturation inhibition and cell death induction exerted by the related species Yersinia enterocolitica WA O:8. Y. pestis interactions with DC were found, however, to impair functions related to cytoskeleton rearrangement. DC pulsed with Y. pestis failed to adhere to solid surfaces and to migrate toward the chemokine CCL19 in an in vitro transmembrane assay. Both effects were dependent on the presence of the pCD1 virulence plasmid and on a bacterial growth shift to 37 degrees C prior to infection. Moreover, while instillation of a pCD1-cured Y. pestis strain into mouse airways triggered effective transport of alveolar DC to the mediastinal lymph node, instillation of Y. pestis harboring the plasmid failed to do so. Taken together, these results suggest that virulence plasmid-dependent impairment of DC migration is the major mechanism utilized by Y. pestis to subvert DC function.

UV Irradiation of Skin Enhances Glycolytic Flux and Reduces Migration Capabilities in Bone Marrow-Differentiated Dendritic Cells.

PubMed

McGonigle, Terence A; Keane, Kevin N; Ghaly, Simon; Carter, Kim W; Anderson, Denise; Scott, Naomi M; Goodridge, Helen S; Dwyer, Amy; Greenland, Eloise; Pixley, Fiona J; Newsholme, Philip; Hart, Prue H

2017-09-01

A systemic immunosuppression follows UV irradiation of the skin of humans and mice. In this study, dendritic cells (DCs) differentiating from the bone marrow (BM) of UV-irradiated mice had a reduced ability to migrate toward the chemokine (C-C motif) ligand 21. Fewer DCs also accumulated in the peritoneal cavity of UV-chimeric mice (ie, mice transplanted with BM from UV-irradiated mice) after injection of an inflammatory stimulus into that site. We hypothesized that different metabolic states underpin altered DC motility. Compared with DCs from the BM of nonirradiated mice, those from UV-irradiated mice produced more lactate, consumed more glucose, and had greater glycolytic flux in a bioenergetics stress test. Greater expression of 3-hydroxyanthranilate 3,4-dioxygenase was identified as a potential contributor to increased glycolysis. Inhibition of 3-hydroxyanthranilate 3,4-dioxygenase by 6-chloro-dl-tryptophan prevented both increased lactate production and reduced migration toward chemokine (C-C motif) ligand 21 by DCs differentiated from BM of UV-irradiated mice. UV-induced prostaglandin E 2 has been implicated as an intermediary in the effects of UV radiation on BM cells. DCs differentiating from BM cells pulsed in vitro for 2 hours with dimethyl prostaglandin E 2 were functionally similar to those from the BM of UV-irradiated mice. Reduced migration of DCs to lymph nodes associated with increased glycolytic flux may contribute to their reduced ability to initiate new immune responses in UV-irradiated mice. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Asthmatic bronchial epithelium activated by the proteolytic allergen Der p 1 increases selective dendritic cell recruitment.

PubMed

Pichavant, Muriel; Charbonnier, Anne-Sophie; Taront, Solenne; Brichet, Anne; Wallaert, Benoît; Pestel, Joel; Tonnel, André-Bernard; Gosset, Philippe

2005-04-01

Airway dendritic cells (DCs) are crucial for allergen-induced sensitization and inflammation in allergic asthma. After allergen challenge, an increased number of DCs is observed in airway epithelium from patients with allergy. Because Der p 1, a cysteine protease allergen from Dermatophagoides pteronyssinus , induces chemokine production by bronchial epithelial cells (BECs), the purpose of this investigation was to evaluate the capacity of BEC exposed to Der p 1 to recruit DCs. Chemotactic activity of BEAS-2B, a bronchial epithelial cell line, and BECs from nonatopic controls and patients with allergic asthma was evaluated on the migration of precursors, immature and mature monocyte-derived DCs (MDDCs), and CD34 + -derived Langerhans cells (LCs). C-C chemokine ligand (CCL)-2, CCL5, and C-X-C chemokine ligand 10 production by BEAS-2B and BEC was increased after Der p 1 exposure, whereas the proenzyme proDer p 1 devoid of enzymatic activity had no effect. Der p 1 stimulation of BEAS-2B and BEC from both groups increased significantly the recruitment of MDDC precursors, depending on CCL2, CCL5, and C-X-C chemokine ligand 10 production. In a reconstituted polarized epithelium, apical application of Der p 1 enhanced MDDC precursor migration into the epithelial layer. Moreover, Der p 1 stimulation of BEC from patients with asthma but not from controls increased the migration of LC precursors, mainly dependent on CCL20 secretion. No migration of immature and mature DCs was observed. These data confirmed that BECs participate in the homeostasis of the DC network present within the bronchial epithelium through the secretion of chemokines. In allergic asthma, upregulation of CCL20 production induced LC recruitment, the role of which remains to be determined.

Soluble TNF receptor 1-secreting ex vivo-derived dendritic cells reduce injury after stroke.

PubMed

Works, Melissa G; Koenig, Jenny B; Sapolsky, Robert M

2013-09-01

Inflammation is a major factor in the progression of damage after stroke and in the clinic, current therapies treat the clot, not the resulting damage. We have developed a novel method of protein delivery that exploits the migration ability of leukocytes after ischemic stroke (transient middle cerebral artery occlusion; tMCAO). In our studies, ex vivo-derived dendritic cells (exDCs) migrate to the inflamed rat brain soon after tMCAO onset and the number of cells that remain in the brain after injection is significantly correlated with the amount of local inflammation at the injury site. In addition, exDCs transduced to overexpress soluble tumor necrosis factor (TNF) receptor1 (sTNFR1) produce functional cargo that is secreted and that blocks TNF-α bioavailability in vitro. When delivered at 6 hours post-tMCAO reperfusion, sTNFR1-exDC-treated rats show significantly smaller infarct size and decreased inflammation compared with animals treated with exDCs transduced with GFP lentivirus. These studies indicate that cell-mediated delivery of proteins may be a promising new approach to reduce brain damage after acute neurologic insult.

Psychological stress exerts an adjuvant effect on skin dendritic cell functions in vivo.

PubMed

Saint-Mezard, Pierre; Chavagnac, Cyril; Bosset, Sophie; Ionescu, Marius; Peyron, Eric; Kaiserlian, Dominique; Nicolas, Jean-Francois; Bérard, Frédéric

2003-10-15

Psychological stress affects the pathophysiology of infectious, inflammatory, and autoimmune diseases. However, the mechanisms by which stress could modulate immune responses in vivo are poorly understood. In this study, we report that application of a psychological stress before immunization exerts an adjuvant effect on dendritic cell (DC), resulting in increased primary and memory Ag-specific T cell immune responses. Acute stress dramatically enhanced the skin delayed-type hypersensitivity reaction to haptens, which is mediated by CD8(+) CTLs. This effect was due to increased migration of skin DCs, resulting in augmented CD8(+) T cell priming in draining lymph nodes and enhanced recruitment of CD8(+) T cell effectors in the skin upon challenge. This adjuvant effect of stress was mediated by norepinephrine (NE), but not corticosteroids, as demonstrated by normalization of the skin delayed-type hypersensitivity reaction and DC migratory properties following selective depletion of NE. These results suggest that release of NE by sympathetic nerve termini during a psychological stress exerts an adjuvant effect on DC by promoting enhanced migration to lymph nodes, resulting in increased Ag-specific T cell responses. Our findings may open new ways in the treatment of inflammatory diseases, e.g., psoriasis, allergic contact dermatitis, and atopic dermatitis.

The Long and Winding Road: From the High-Affinity Choline Uptake Site to Clinical Trials for Malignant Brain Tumors.

PubMed

Lowenstein, P R; Castro, M G

2016-01-01

Malignant brain tumors are one of the most lethal cancers. They originate from glial cells which infiltrate throughout the brain. Current standard of care involves surgical resection, radiotherapy, and chemotherapy; median survival is currently ~14-20 months postdiagnosis. Given that the brain immune system is deficient in priming systemic immune responses to glioma antigens, we proposed to reconstitute the brain immune system to achieve immunological priming from within the brain. Two adenoviral vectors are injected into the resection cavity or remaining tumor. One adenoviral vector expresses the HSV-1-derived thymidine kinase which converts ganciclovir into a compound only cytotoxic to dividing glioma cells. The second adenovirus expresses the cytokine fms-like tyrosine kinase 3 ligand (Flt3L). Flt3L differentiates precursors into dendritic cells and acts as a chemokine that attracts dendritic cells to the brain. HSV-1/ganciclovir killing of tumor cells releases tumor antigens that are taken up by dendritic cells within the brain tumor microenvironment. Tumor killing also releases HMGB1, an endogenous TLR2 agonist that activates dendritic cells. HMGB1-activated dendritic cells, loaded with glioma antigens, migrate to cervical lymph nodes to stimulate a systemic CD8+ T cells cytotoxic immune response against glioma. This immune response is specific to glioma tumors, induces immunological memory, and does neither cause brain toxicity nor autoimmune responses. An IND was granted by the FDA on 4/7/2011. A Phase I, first in person trial, to test whether reengineering the brain immune system is potentially therapeutic is ongoing. © 2016 Elsevier Inc. All rights reserved.

Optimization of Dendritic Cell-Mediated Cytotoxic T-Cell Activation by Tracking of Dendritic Cell Migration Using Reporter Gene Imaging.

PubMed

Lee, Hongje; Lee, Ho Won; La Lee, You; Jeon, Yong Hyun; Jeong, Shin Young; Lee, Sang-Woo; Lee, Jaetae; Ahn, Byeong-Cheol

2018-06-01

The aim of this study is to optimize the dendritic cell (DC)-mediated T-cell activation using reporter gene imaging and flow cytometric analysis in living mice. A murine dendritic cell line (DC2.4) co-expressing effluc and Thy1.1 genes were established by transfection with retroviral vectors. Thy1.1 positive cells were sorted by magnetic bead separation system (DC2.4/effluc). Cell proliferation assay and phenotype analysis to determine the effects of gene transduction on the function of dendritic cells between parental DC2.4 and DC2.4/effluc were performed. To optimize the DC-mediated immune response by cell number or frequency, different cell numbers (5 × 10 5 , 1 × 10 6 , and 2 × 10 6  DC2.4/effluc) or different frequencies of DC2.4/effluc (first, second, and third injections) were injected in the right footpad of mice. The migration of the DC2.4/effluc into the draining popliteal lymph node of mice was monitored by bioluminescence imaging (BLI). Flow cytometric analysis was performed with splenocytes to determine the cytotoxic T-cell population after injection of DC2.4/effluc. Parental DC2.4 and DC2.4/effluc exhibit no significant differences in their proliferation and phenotype. BLI signals were observed in the draining popliteal lymph node at day 1 after injection of DC2.4/effluc in 1 × 10 6 and 2 × 10 6 cells-injected groups. The highest BLI signal intensity was detected in 2 × 10 6 cells-injected mice. On day 11, the BLI signal was detected in only 2 × 10 6 cell-injected group but not in other groups. Optimized cell numbers (2 × 10 6 ) were injected in three animal groups with a different frequency (first, second, and third injection groups). The BLI signal was detected at day 1 and maintained until day 7 in the first injection group, but there is low signal intensity in the second and the third injection groups. Although the expression levels of Thy1.1 gene in the first injection group were very high, there reveals no expression of Thy1.1 gene in the second and the third injection groups. The number of tumor-specific CD8 + T-cells in the spleen significantly increased, as the number of DC injections increases. Successful optimization of DC-mediated cytotoxic T-cell activation in living mice using reporter gene imaging and flow cytometric analysis was achieved. The optimization of DC-mediated cytotoxic T-cell activation could be applied for the future DC-based immunotherapy.

Four-Dimensional Imaging of T Cells in Kidney Transplant Rejection.

PubMed

Hughes, Andrew D; Lakkis, Fadi G; Oberbarnscheidt, Martin H

2018-06-01

Kidney transplantation is the treatment of choice for ESRD but is complicated by the response of the recipient's immune system to nonself histocompatibility antigens on the graft, resulting in rejection. Multiphoton intravital microscopy, referred to as four-dimensional imaging because it records dynamic events in three-dimensional tissue volumes, has emerged as a powerful tool to study immunologic processes in living animals. Here, we will review advances in understanding the complex mechanisms of T cell-mediated rejection made possible by four-dimensional imaging of mouse renal allografts. We will summarize recent data showing that activated (effector) T cell migration to the graft is driven by cognate antigen presented by dendritic cells that surround and penetrate peritubular capillaries, and that T cell-dendritic cell interactions persist in the graft over time, maintaining the immune response in the tissue. Copyright © 2018 by the American Society of Nephrology.

Human skin dendritic cells in health and disease.

PubMed

Haniffa, Muzlifah; Gunawan, Merry; Jardine, Laura

2015-02-01

Dendritic cells (DCs) are specialized antigen presenting cells abundant in peripheral tissues such as skin where they function as immune sentinels. Skin DCs migrate to draining lymph node where they interact with naïve T cells to induce immune responses to microorganisms, vaccines, tumours and self-antigens. In this review, we present the key historical developments and recent advances in human skin DC research. We also integrate the current understanding on the origin and functional specializations of DC subsets in healthy skin with findings in inflammatory skin diseases focusing on psoriasis and atopic eczema. A comprehensive understanding of the dynamic changes in DC subsets in health and disease will form a strong foundation to facilitate the clinical translation of DC-based therapeutic and vaccination strategies. Copyright © 2014 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

CXCL16 and CXCR6 are upregulated in psoriasis and mediate cutaneous recruitment of human CD8+ T cells.

PubMed

Günther, Claudia; Carballido-Perrig, Nicole; Kaesler, Susanne; Carballido, José M; Biedermann, Tilo

2012-03-01

Psoriatic skin lesions are characterized by an inflammatory infiltrate, consisting of dendritic cells, monocytes, and both CD4(+) and CD8(+) T lymphocytes. Although the chemokines involved in the migration of CD4(+) T cells into psoriatic skin are well characterized, those regulating CD8(+) T-cell recruitment are less understood. We found that the percentages of peripheral blood CD8(+) T cells expressing CXCR6 were higher in psoriatic patients than in healthy or atopic individuals. In addition, CXCR6 expression in psoriatic patients was more abundant in the CD8(+) than in the CD4(+) T-cell compartment. CXCR6 mRNA expression was also stronger in skin CD8(+) T cells than in the corresponding blood-derived counterparts. Immunofluorescence analysis revealed profound upregulation of the CXCR6 ligand CXCL16 by monocytes, keratinocytes, and dendritic cells in psoriatic skin compared with healthy or atopic dermatitis skin. In line with this, CXCR6(+) CD8(+) T cells also were most prevalent in psoriatic skin. Furthermore, CXCL16 induced Ca(2+) influx and chemotactic migration of psoriatic skin-derived CD8(+) T cells in vitro. Most importantly, CXCL16 potently recruited human CD8(+) T cells to human skin grafts previously transplanted onto SCID mice in vivo. These investigations indicate that CXCL16-CXCR6 interactions mediate homing of CD8(+) T cells into human skin, and thereby contribute to psoriasis pathogenesis.

HMGB1, an alarmin promoting HIV dissemination and latency in dendritic cells

PubMed Central

Gougeon, M-L; Melki, M-T; Saïdi, H

2012-01-01

Dendritic cells (DCs) initiate immune responses by transporting antigens and migrating to lymphoid tissues to initiate T-cell responses. DCs are located in the mucosal surfaces that are involved in human immunodeficiency virus (HIV) transmission and they are probably among the earliest targets of HIV-1 infection. DCs have an important role in viral transmission and dissemination, and HIV-1 has evolved different strategies to evade DC antiviral activity. High mobility group box 1 (HMGB1) is a DNA-binding nuclear protein that can act as an alarmin, a danger signal to alert the innate immune system for the initiation of host defense. It is the prototypic damage-associated molecular pattern molecule, and it can be secreted by innate cells, including DCs and natural killer (NK) cells. The fate of DCs is dependent on a cognate interaction with NK cells, which involves HMGB1 expressed at NK–DC synapse. HMGB1 is essential for DC maturation, migration to lymphoid tissues and functional type-1 polarization of naïve T cells. This review highlights the latest advances in our understanding of the impact of HIV on the interactions between HMGB1 and DCs, focusing on the mechanisms of HMGB1-dependent viral dissemination and persistence in DCs, and discussing the consequences on antiviral innate immunity, immune activation and HIV pathogenesis. PMID:22033335

Tetraspanin CD37 contributes to the initiation of cellular immunity by promoting dendritic cell migration.

PubMed

Gartlan, Kate H; Wee, Janet L; Demaria, Maria C; Nastovska, Roza; Chang, Tsz Man; Jones, Eleanor L; Apostolopoulos, Vasso; Pietersz, Geoffrey A; Hickey, Michael J; van Spriel, Annemiek B; Wright, Mark D

2013-05-01

Previous studies on the role of the tetraspanin CD37 in cellular immunity appear contradictory. In vitro approaches indicate a negative regulatory role, whereas in vivo studies suggest that CD37 is necessary for optimal cellular responses. To resolve this discrepancy, we studied the adaptive cellular immune responses of CD37(-/-) mice to intradermal challenge with either tumors or model antigens and found that CD37 is essential for optimal cell-mediated immunity. We provide evidence that an increased susceptibility to tumors observed in CD37(-/-) mice coincides with a striking failure to induce antigen-specific IFN-γ-secreting T cells. We also show that CD37 ablation impairs several aspects of DC function including: in vivo migration from skin to draining lymph nodes; chemo-tactic migration; integrin-mediated adhesion under flow; the ability to spread and form actin protrusions and in vivo priming of adoptively transferred naïve T cells. In addition, multiphoton microscopy-based assessment of dermal DC migration demonstrated a reduced rate of migration and increased randomness of DC migration in CD37(-/-) mice. Together, these studies are consistent with a model in which the cellular defect that underlies poor cellular immune induction in CD37(-/-) mice is impaired DC migration. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The meningeal lymphatic system: a route for HIV brain migration?

PubMed

Lamers, Susanna L; Rose, Rebecca; Ndhlovu, Lishomwa C; Nolan, David J; Salemi, Marco; Maidji, Ekaterina; Stoddart, Cheryl A; McGrath, Michael S

2016-06-01

Two innovative studies recently identified functional lymphatic structures in the meninges that may influence the development of HIV-associated neurological disorders (HAND). Until now, blood vessels were assumed to be the sole transport system by which HIV-infected monocytes entered the brain by bypassing a potentially hostile blood-brain barrier through inflammatory-mediated semi-permeability. A cascade of specific chemokine signals promote monocyte migration from blood vessels to surrounding brain tissues via a well-supported endothelium, where the cells differentiate into tissue macrophages capable of productive HIV infection. Lymphatic vessels on the other hand are more loosely organized than blood vessels. They absorb interstitial fluid from bodily tissues where HIV may persist and exchange a variety of immune cells (CD4(+) T cells, monocytes, macrophages, and dendritic cells) with surrounding tissues through discontinuous endothelial junctions. We propose that the newly discovered meningeal lymphatics are key to HIV migration among viral reservoirs and brain tissue during periods of undetectable plasma viral loads due to suppressive combinational antiretroviral therapy, thus redefining the migration process in terms of a blood-lymphatic transport system.

Toxoplasma gondii infection shifts dendritic cells into an amoeboid rapid migration mode encompassing podosome dissolution, secretion of TIMP-1, and reduced proteolysis of extracellular matrix.

PubMed

Ólafsson, Einar B; Varas-Godoy, Manuel; Barragan, Antonio

2018-03-01

Dendritic cells (DCs) infected by Toxoplasma gondii rapidly acquire a hypermigratory phenotype that promotes systemic parasite dissemination by a "Trojan horse" mechanism in mice. Recent paradigms of leukocyte migration have identified the amoeboid migration mode of DCs as particularly suited for rapid locomotion in extracellular matrix and tissues. Here, we have developed a microscopy-based high-throughput approach to assess motility and matrix degradation by Toxoplasma-challenged murine and human DCs. DCs challenged with T. gondii exhibited dependency on metalloproteinase activity for hypermotility and transmigration but, strikingly, also dramatically reduced pericellular proteolysis. Toxoplasma-challenged DCs up-regulated expression and secretion of tissue inhibitor of metalloproteinases-1 (TIMP-1) and their supernatants impaired matrix degradation by naïve DCs and by-stander DCs dose dependently. Gene silencing of TIMP-1 by short hairpin RNA restored matrix degradation activity in Toxoplasma-infected DCs. Additionally, dissolution of podosome structures in parasitised DCs coincided with abrogated matrix degradation. Toxoplasma lysates inhibited pericellular proteolysis in a MyD88-dependent fashion whereas abrogated proteolysis persevered in Toxoplasma-infected MyD88-deficient DCs. This indicated that both TLR/MyD88-dependent and TLR/MyD88-independent signalling pathways mediated podosome dissolution and the abrogated matrix degradation. We report that increased TIMP-1 secretion and cytoskeletal rearrangements encompassing podosome dissolution are features of Toxoplasma-induced hypermigration of DCs with an impact on matrix degradation. Jointly, the data highlight how an obligate intracellular parasite orchestrates key regulatory cellular processes consistent with non-proteolytic amoeboid migration of the vehicle cells that facilitate its dissemination. © 2017 John Wiley & Sons Ltd.

Polyelectrolyte coating of ferumoxytol nanoparticles for labeling of dendritic cells

NASA Astrophysics Data System (ADS)

Celikkin, Nehar; Jakubcová, Lucie; Zenke, Martin; Hoss, Mareike; Wong, John Erik; Hieronymus, Thomas

2015-04-01

Engineered magnetic nanoparticles (MNPs) are emerging to be used as cell tracers, drug delivery vehicles, and contrast agents for magnetic resonance imaging (MRI) for enhanced theragnostic applications in biomedicine. In vitro labeling of target cell populations with MNPs and their implantation into animal models and patients shows promising outcomes in monitoring successful cell engraftment, differentiation and migration by using MRI. Dendritic cells (DCs) are professional antigen-presenting cells that initiate adaptive immune responses. Thus, DCs have been the focus of cellular immunotherapy and are increasingly applied in clinical trials. Here, we addressed the coating of different polyelectrolytes (PE) around ferumoxytol particles using the layer-by-layer technique. The impact of PE-coated ferumoxytol particles for labeling of DCs and Flt3+ DC progenitors was then investigated. The results from our studies revealed that PE-coated ferumoxytol particles can be readily employed for labeling of DC and DC progenitors and thus are potentially suitable as contrast agents for MRI tracking.

Trans-nodal migration of resident dendritic cells into medullary interfollicular regions initiates immunity to influenza vaccine

PubMed Central

Woodruff, Matthew C.; Heesters, Balthasar A.; Herndon, Caroline N.; Groom, Joanna R.; Thomas, Paul G.; Luster, Andrew D.; Turley, Shannon J.

2014-01-01

Dendritic cells (DCs) are well established as potent antigen-presenting cells critical to adaptive immunity. In vaccination approaches, appropriately stimulating lymph node–resident DCs (LNDCs) is highly relevant to effective immunization. Although LNDCs have been implicated in immune response, their ability to directly drive effective immunity to lymph-borne antigen remains unclear. Using an inactive influenza vaccine model and whole node imaging approaches, we observed surprising responsiveness of LNDC populations to vaccine arrival resulting in a transnodal repositioning into specific antigen collection sites within minutes after immunization. Once there, LNDCs acquired viral antigen and initiated activation of viral specific CD4+ T cells, resulting in germinal center formation and B cell memory in the absence of skin migratory DCs. Together, these results demonstrate an unexpected stimulatory role for LNDCs where they are capable of rapidly locating viral antigen, driving early activation of T cell populations, and independently establishing functional immune response. PMID:25049334

Maturation of monocyte derived dendritic cells with OK432 boosts IL-12p70 secretion and conveys strong T-cell responses

PubMed Central

2011-01-01

Background Design of tumour specific immunotherapies using the patients' own dendritic cells (DC) is a fast advancing scientific field. The functional qualities of the DC generated in vitro are critical, and today's gold standard for maturation is a cytokine cocktail consisting of IL-1β, IL-6, TNF-α and PGE2 generating cells lacking IL-12p70 production. OK432 is an immunotherapeutic agent derived from killed Streptococcus pyogenes that has been used clinically to treat malignant and benign neoplasms for decades. Methods In this study, we analysed the effects of OK432 on DC maturation, DC migration, cytokine and chemokine secretion as well as T-cell stimulatory capacity, and compared it to the cytokine cocktail alone and combinations of OK432 with the cytokine cocktail. Results OK432 induced a marked up-regulation of CD40 on the cell surface as well as a strong inflammatory response from the DC with significantly more secretion of 19 different cytokines and chemokines compared to the cytokine cocktail. Interestingly, secretion of IL-15 and IL-12p70 was detected at high concentrations after maturation of DC with OK432. However, the OK432 treated DC did not migrate as well as DC treated with cytokine cocktail in a transwell migration assay. During allogeneic T-cell stimulation OK432 treated DC induced proliferation of over 50 percent of CD4 and 30 percent of CD8 T-cells for more than two cell divisions, whereas cytokine cocktail treated DC induced proliferation of 12 and 11 percent of CD4 and CD8 T-cells, respectively. Conclusions The clinically approved compound OK432 has interesting properties that warrants its use in DC immunotherapy and should be considered as a potential immunomodulating agent in cancer immunotherapy. PMID:21208424

Chemokine Receptor Ccr7 Restricts Fatal West Nile Virus Encephalitis.

PubMed

Bardina, Susana V; Brown, Julia A; Michlmayr, Daniela; Hoffman, Kevin W; Sum, Janet; Pletnev, Alexander G; Lira, Sergio A; Lim, Jean K

2017-05-15

West Nile virus (WNV) is a mosquito-transmitted flavivirus that can cause debilitating encephalitis. To delineate the mechanisms behind this pathology, we studied Ccr7-deficient mice, which afforded us the capacity to study infection in mice with disrupted peripheral cellular trafficking events. The loss of Ccr7 resulted in an immediate pan-leukocytosis that remained elevated throughout the infection. This leukocytosis resulted in a significant enhancement of leukocyte accumulation within the central nervous system (CNS). Despite an excess of virus-specific T cells in the CNS, Ccr7-deficient mice had significantly higher CNS viral loads and mortality rates than wild-type animals. Mechanistically, the elevated trafficking of infected myeloid cells into the brain in Ccr7-deficient mice resulted in increased levels of WNV in the CNS, thereby effectively contributing to neuroinflammation and lowering viral clearance. Combined, our experiments suggest that during WNV infection, Ccr7 is a gatekeeper for nonspecific viral transference to the brain. IMPORTANCE In this study, we show that Ccr7 is required for the sufficient migration of dendritic cells and T cells into the draining lymph node immediately following infection and for the restriction of leukocyte migration into the brain. Further, the severe loss of dendritic cells in the draining lymph node had no impact on viral replication in this organ, suggesting that WNV may migrate from the skin into the lymph node through another mechanism. Most importantly, we found that the loss of Ccr7 results in a significant leukocytosis, leading to hypercellularity within the CNS, where monocytes/macrophages contribute to CNS viremia, neuroinflammation, and increased mortality. Together, our data point to Ccr7 as a critical host defense restriction factor limiting neuroinflammation during acute viral infection. Copyright © 2017 American Society for Microbiology.

Ba2+- and bupivacaine-sensitive background K+ conductances mediate rapid EPSP attenuation in oligodendrocyte precursor cells

PubMed Central

Chan, Chu-Fang; Kuo, Tzu-Wei; Weng, Ju-Yun; Lin, Yen-Chu; Chen, Ting-Yu; Cheng, Jen-Kun; Lien, Cheng-Chang

2013-01-01

Glutamatergic transmission onto oligodendrocyte precursor cells (OPCs) may regulate OPC proliferation, migration and differentiation. Dendritic integration of excitatory postsynaptic potentials (EPSPs) is critical for neuronal functions, and mechanisms regulating dendritic propagation and summation of EPSPs are well understood. However, little is known about EPSP attenuation and integration in OPCs. We developed realistic OPC models for synaptic integration, based on passive membrane responses of OPCs obtained by simultaneous dual whole-cell patch-pipette recordings. Compared with neurons, OPCs have a very low value of membrane resistivity, which is largely mediated by Ba2+- and bupivacaine-sensitive background K+ conductances. The very low membrane resistivity not only leads to rapid EPSP attenuation along OPC processes but also sharpens EPSPs and narrows the temporal window for EPSP summation. Thus, background K+ conductances regulate synaptic responses and integration in OPCs, thereby affecting activity-dependent neuronal control of OPC development and function. PMID:23940377

Curcumin prevents human dendritic cell response to immune stimulants

PubMed Central

Shirley, Shawna A.; Montpetit, Alison J.; Lockey, R.F.; Mohapatra, Shyam S.

2012-01-01

Curcumin, a compound found in the Indian spice turmeric, has anti-inflammatory and immunomodulatory properties, though the mechanism remains unclear. Dendritic cells (DCs) are important to generating an immune response and the effect of curcumin on human DCs has not been explored. The role curcumin in the DC response to bacterial and viral infection was investigated in vitro using LPS and Poly I:C as models of infection. CD14+ monocytes, isolated from human peripheral blood, were cultured in GM-CSF- and IL-4-supplemented medium to generate immature DCs. Cultures were incubated with curcumin, stimulated with LPS or Poly I:C and functional assays were performed. Curcumin prevents DCs from responding to immunostimulants and inducing naïve CD4+ T cell proliferation by blocking maturation marker, cytokine and chemokine expression and reducing both migration and endocytosis. These data suggest a therapeutic role for curcumin as an immune suppressant. PMID:18639521

Curcumin prevents human dendritic cell response to immune stimulants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shirley, Shawna A.; Montpetit, Alison J.; Lockey, R.F.

2008-09-26

Curcumin, a compound found in the Indian spice turmeric, has anti-inflammatory and immunomodulatory properties, though the mechanism remains unclear. Dendritic cells (DCs) are important to generating an immune response and the effect of curcumin on human DCs has not been explored. The role curcumin in the DC response to bacterial and viral infection was investigated in vitro using LPS and Poly I:C as models of infection. CD14{sup +} monocytes, isolated from human peripheral blood, were cultured in GM-CSF- and IL-4-supplemented medium to generate immature DCs. Cultures were incubated with curcumin, stimulated with LPS or Poly I:C and functional assays weremore » performed. Curcumin prevents DCs from responding to immunostimulants and inducing CD4{sup +} T cell proliferation by blocking maturation marker, cytokine and chemokine expression and reducing both migration and endocytosis. These data suggest a therapeutic role for curcumin as an immune suppressant.« less

Formation of retinal direction-selective circuitry initiated by starburst amacrine cell homotypic contact

PubMed Central

Ray, Thomas A; Roy, Suva; Kozlowski, Christopher; Wang, Jingjing; Cafaro, Jon; Hulbert, Samuel W; Wright, Christopher V; Field, Greg D

2018-01-01

A common strategy by which developing neurons locate their synaptic partners is through projections to circuit-specific neuropil sublayers. Once established, sublayers serve as a substrate for selective synapse formation, but how sublayers arise during neurodevelopment remains unknown. Here, we identify the earliest events that initiate formation of the direction-selective circuit in the inner plexiform layer of mouse retina. We demonstrate that radially migrating newborn starburst amacrine cells establish homotypic contacts on arrival at the inner retina. These contacts, mediated by the cell-surface protein MEGF10, trigger neuropil innervation resulting in generation of two sublayers comprising starburst-cell dendrites. This dendritic scaffold then recruits projections from circuit partners. Abolishing MEGF10-mediated contacts profoundly delays and ultimately disrupts sublayer formation, leading to broader direction tuning and weaker direction-selectivity in retinal ganglion cells. Our findings reveal a mechanism by which differentiating neurons transition from migratory to mature morphology, and highlight this mechanism’s importance in forming circuit-specific sublayers. PMID:29611808

Dendritic cells: importance in allergy.

PubMed

Aiba, Setsuya

2007-09-01

In this review we discuss the role of dendritic cells (DC) in the pathogenesis of allergic contact hypersensitivity (ACH) and atopic disorders, such as asthma and atopic eczema. In ACH patients, DC recognize the invasion of simple chemicals such as haptens, and trigger antigen-specific T cell responses leading to the characteristic histological and clinical changes such as spongiosis and papulovesicular eruptions. During atopic disorders, it is well known that the Th2-deviated immune response plays a crucial role in their pathogenesis. DC provide T cells with antigen and costimulatory signals (signals 1 and 2, respectively), as well as with a polarizing signal (signal 3). When studying ACH, it is important to understand how simple chemicals induce the activation of DC and their migration to the draining lymph nodes where they supply signals 1 and 2 to naive T cells. The mechanisms by which DC induce the Th2-deviated immune response, namely via the Th2-deviated signal 3, are central topics in the pathogenesis of atopic disorders.

Electrolytic Migration of Ag-Pd Alloy Wires with Various Pd Contents

NASA Astrophysics Data System (ADS)

Lin, Yan-Cheng; Chen, Chun-Hao; He, Yu-Zhen; Chen, Sheng-Chi; Chuang, Tung-Han

2018-07-01

During Ag ion migration in an aqueous water drop covering a pair of parallel Ag-Pd wires under current stressing, hydrogen bubbles form first from the cathode, followed by the appearance of pure Ag dendrites on the cathodic wire. In this study, Ag dendrites with a diameter of 0.2-0.4 μm grew toward the anodic wire. The growth rate ( v) of these dendrites decreased with the Pd content ( c) with a linear relationship of: v = 10.02 - 0.43 c . Accompanying the growth of pure Ag dendrites was the formation of a continuous layer of crystallographic Ag2O particles on the surface of the anodic wire. The deposition of such insulating Ag2O products did not prevent the contact of Ag dendrites with the anodic Ag-Pd wire or the short circuit of the wire couple.

Electrolytic Migration of Ag-Pd Alloy Wires with Various Pd Contents

NASA Astrophysics Data System (ADS)

Lin, Yan-Cheng; Chen, Chun-Hao; He, Yu-Zhen; Chen, Sheng-Chi; Chuang, Tung-Han

2018-03-01

During Ag ion migration in an aqueous water drop covering a pair of parallel Ag-Pd wires under current stressing, hydrogen bubbles form first from the cathode, followed by the appearance of pure Ag dendrites on the cathodic wire. In this study, Ag dendrites with a diameter of 0.2-0.4 μm grew toward the anodic wire. The growth rate (v) of these dendrites decreased with the Pd content (c) with a linear relationship of: v = 10.02 - 0.43 c . Accompanying the growth of pure Ag dendrites was the formation of a continuous layer of crystallographic Ag2O particles on the surface of the anodic wire. The deposition of such insulating Ag2O products did not prevent the contact of Ag dendrites with the anodic Ag-Pd wire or the short circuit of the wire couple.

Eph and Ephrin function in dispersal and epithelial insertion of pigmented immunocytes in sea urchin embryos

PubMed Central

Krupke, Oliver A; Zysk, Ivona; Mellott, Dan O; Burke, Robert D

2016-01-01

The mechanisms that underlie directional cell migration are incompletely understood. Eph receptors usually guide migrations of cells by exclusion from regions expressing Ephrin. In sea urchin embryos, pigmented immunocytes are specified in vegetal epithelium, transition to mesenchyme, migrate, and re-enter ectoderm, distributing in dorsal ectoderm and ciliary band, but not ventral ectoderm. Immunocytes express Sp-Eph and Sp-Efn is expressed throughout dorsal and ciliary band ectoderm. Interfering with expression or function of Sp-Eph results in rounded immunocytes entering ectoderm but not adopting a dendritic form. Expressing Sp-Efn throughout embryos permits immunocyte insertion in ventral ectoderm. In mosaic embryos, immunocytes insert preferentially in ectoderm expressing Sp-Efn. We conclude that Sp-Eph signaling is necessary and sufficient for epithelial insertion. As well, we propose that immunocytes disperse when Sp-Eph enhances adhesion, causing haptotactic movement to regions of higher ligand abundance. This is a distinctive example of Eph/Ephrin signaling acting positively to pattern migrating cells. DOI: http://dx.doi.org/10.7554/eLife.16000.001 PMID:27474796

HIV turns plasmacytoid dendritic cells (pDC) into TRAIL-expressing killer pDC and down-regulates HIV coreceptors by Toll-like receptor 7-induced IFN-alpha.

PubMed

Hardy, Andrew W; Graham, David R; Shearer, Gene M; Herbeuval, Jean-Philippe

2007-10-30

Plasmacytoid dendritic cells (pDC) are key players in viral immunity and produce IFN-alpha after HIV-1 exposure, which in turn regulates TNF-related apoptosis-inducing ligand (TRAIL) expression by CD4(+) T cells. We show here that infectious and noninfectious HIV-1 virions induce activation of pDC into TRAIL-expressing IFN-producing killer pDC (IKpDC). IKpDC expressed high levels of activation markers (HLA-DR, CD80, CD83, and CD86) and the migration marker CCR7. Surprisingly, CXCR4 and CCR5 were down-regulated on IKpDC. We also show that HIV-1-induced IKpDC depended on Toll-like receptor 7 (TLR7) activation. HIV-1 or TLR7 agonistexposed IKpDC induced apoptosis of the CD4(+) T cell line SupT1 via the TRAIL pathway. Furthermore, IFN-alpha produced after HIV-induced TLR7 stimulation was responsible for TRAIL expression and the down-regulation of both CXCR4 and CCR5 by IKpDC. In contrast, activation and migration markers were not regulated by IFN-alpha. Finally, IFN-alpha increased the survival of IKpDC. We characterized a subset of pDC with a killer activity that is activated by endosomal-associated viral RNA and not by infection.

Computational model of mesenchymal migration in 3D under chemotaxis.

PubMed

Ribeiro, F O; Gómez-Benito, M J; Folgado, J; Fernandes, P R; García-Aznar, J M

2017-01-01

Cell chemotaxis is an important characteristic of cellular migration, which takes part in crucial aspects of life and development. In this work, we propose a novel in silico model of mesenchymal 3D migration with competing protrusions under a chemotactic gradient. Based on recent experimental observations, we identify three main stages that can regulate mesenchymal chemotaxis: chemosensing, dendritic protrusion dynamics and cell-matrix interactions. Therefore, each of these features is considered as a different module of the main regulatory computational algorithm. The numerical model was particularized for the case of fibroblast chemotaxis under a PDGF-bb gradient. Fibroblasts migration was simulated embedded in two different 3D matrices - collagen and fibrin - and under several PDGF-bb concentrations. Validation of the model results was provided through qualitative and quantitative comparison with in vitro studies. Our numerical predictions of cell trajectories and speeds were within the measured in vitro ranges in both collagen and fibrin matrices. Although in fibrin, the migration speed of fibroblasts is very low, because fibrin is a stiffer and more entangling matrix. Testing PDGF-bb concentrations, we noticed that an increment of this factor produces a speed increment. At 1 ng mL -1 a speed peak is reached after which the migration speed diminishes again. Moreover, we observed that fibrin exerts a dampening behavior on migration, significantly affecting the migration efficiency.

Diesel Exhaust Exposure Increases Susceptibility to Influenza Infection and Induces Dendritic Cell Migration and Maturation.

EPA Science Inventory

Mice were necropsied at day 1, 4, 8 and 14 post-infection and lung tissue was assessed for virus titers by TCID₅₀, lung injury and inflammation. Lung and lymph node DC populations (CD11c⁺, MHCII, CD45⁺, CD80⁺ and CD86+) were identified ...

Dendritic cells from CML patients have altered actin organization, reduced antigen processing, and impaired migration.

PubMed

Dong, Rong; Cwynarski, Kate; Entwistle, Alan; Marelli-Berg, Federica; Dazzi, Francesco; Simpson, Elizabeth; Goldman, John M; Melo, Junia V; Lechler, Robert I; Bellantuono, Ilaria; Ridley, Anne; Lombardi, Giovanna

2003-05-01

Chronic myeloid leukemia (CML) is characterized by expression of the BCR-ABL fusion gene that encodes a 210-kDa protein, which is a constitutively active tyrosine kinase. At least 70% of the oncoprotein is localized to the cytoskeleton, and several of the most prominent tyrosine kinase substrates for p210(BCR-ABL) are cytoskeletal proteins. Dendritic cells (DCs) are bone marrow-derived antigen-presenting cells responsible for the initiation of immune responses. In CML patients, up to 98% of myeloid DCs generated from peripheral blood mononuclear cells are BCR-ABL positive. In this study we have compared the morphology and behavior of myeloid DCs derived from CML patients with control DCs from healthy individuals. We show that the actin cytoskeleton and shape of CML-DCs of myeloid origin adherent to fibronectin differ significantly from those of normal DCs. CML-DCs are also defective in processing and presentation of exogenous antigens such as tetanus toxoid. The antigen-processing defect may be a consequence of the reduced capacity of CML-DCs to capture antigen via macropinocytosis or via mannose receptors when compared with DCs generated from healthy individuals. Furthermore, chemokine-induced migration of CML-DCs in vitro was significantly reduced. These observations cannot be explained by a difference in the maturation status of CML and normal DCs, because phenotypic analysis by flow cytometry showed a similar surface expression of maturation makers. Taken together, these results suggest that the defects in antigen processing and migration we have observed in CML-DCs may be related to underlying cytoskeletal changes induced by the p210(BCR-ABL) fusion protein.

Effects of 12C6+ Heavy Ion Radiation on Dendritic Cells Function

PubMed Central

Zhang, Pei; Hu, Xuguang; Liu, Bin; Liu, Zhe; Liu, Cong; Cai, Jianming; Gao, Fu; Li, Bailong

2018-01-01

Background Carbon ion radiotherapy has been shown to be more effective in cancer radiotherapy than photon irradiation. Influence of carbon ion radiation on cancer microenvironment is very important for the outcomes of radiotherapy. Tumor-infiltrating dendritic cells (DCs) play critical roles in cancer antigen processing and antitumor immunity. However, there is scant literature covering the effects of carbon ion radiation on DCs. In this study, we aimed to uncover the impact of carbon ion irradiation on bone marrow derived DCs. Material/Methods Bone marrow cells were co-cultured with GM-CSF and IL-4 for seven days, and the population of DCs was confirmed with flow cytometry. We used an Annexin V and PI staining method to detect cell apoptosis. Endocytosis assay of DCs was determined by using a flow cytometry method. DCs migration capacity was tested by a Transwell method. We also used ELISA assay and western blotting assay to examine the cytokines and protein expression, respectively. Results Our data showed that carbon ion radiation induced apoptosis in both immature and mature DCs. After irradiation, the endocytosis and migration capacity of DCs was also impaired. Interestingly, carbon irradiation triggered a burst of IFN-γ and IL-12 in LPS or CpG treated DCs, which provide novel insights into the combination of immunotherapy and carbon ion radiotherapy. Finally, we found that carbon ion irradiation induced apoptosis and migration suppression was p38 dependent. Conclusions Our present study demonstrated that carbon ion irradiation induced apoptosis in DCs, and impaired DCs function mainly through the p38 signaling pathway. Carbon ion irradiation also triggered anti-tumor cytokines secretion. This work provides novel information of carbon ion radiotherapy in DCs, and also provides new insights on the combination of immune adjuvant and carbon ion radiotherapy. PMID:29525808

Local thermal injury elicits immediate dynamic behavioural responses by corneal Langerhans cells

PubMed Central

Ward, Brant R; Jester, James V; Nishibu, Akiko; Vishwanath, Mridula; Shalhevet, David; Kumamoto, Tadashi; Petroll, W Matthew; Cavanagh, H Dwight; Takashima, Akira

2007-01-01

Langerhans cells (LCs) represent a special subset of immature dendritic cells (DCs) that reside in epithelial tissues at the environmental interfaces. Although dynamic interactions of mature DCs with T cells have been visualized in lymph nodes, the cellular behaviours linked with the surveillance of tissues for pathogenic signals, an important function of immature DCs, remain unknown. To visualize LCs in situ, bone marrow cells from C57BL/6 mice expressing the enhanced green fluorescent protein (EGFP) transgene were transplanted into syngeneic wild-type recipients. Motile activities of EGFP+ corneal LCs in intact organ cultures were then recorded by time lapse two-photon microscopy. At baseline, corneal LCs exhibited a unique motion, termed dendrite surveillance extension and retraction cycling habitude (dSEARCH), characterized by rhythmic extension and retraction of their dendritic processes through intercellular spaces between epithelial cells. Upon pinpoint injury produced by infrared laser, LCs showed augmented dSEARCH and amoeba-like lateral movement. Interleukin (IL)-1 receptor antagonist completely abrogated both injury-associated changes, suggesting roles for IL-1. In the absence of injury, exogenous IL-1 caused a transient increase in dSEARCH without provoking lateral migration, whereas tumour necrosis factor-α induced both changes. Our results demonstrate rapid cytokine-mediated behavioural responses by LCs to local tissue injury, providing new insights into the biology of LCs. PMID:17250587

Clonal Analysis of Newborn Hippocampal Dentate Granule Cell Proliferation and Development in Temporal Lobe Epilepsy1,2,3

PubMed Central

LaSarge, Candi L.; McAuliffe, John J.

2015-01-01

Abstract Hippocampal dentate granule cells are among the few neuronal cell types generated throughout adult life in mammals. In the normal brain, new granule cells are generated from progenitors in the subgranular zone and integrate in a typical fashion. During the development of epilepsy, granule cell integration is profoundly altered. The new cells migrate to ectopic locations and develop misoriented “basal” dendrites. Although it has been established that these abnormal cells are newly generated, it is not known whether they arise ubiquitously throughout the progenitor cell pool or are derived from a smaller number of “bad actor” progenitors. To explore this question, we conducted a clonal analysis study in mice expressing the Brainbow fluorescent protein reporter construct in dentate granule cell progenitors. Mice were examined 2 months after pilocarpine-induced status epilepticus, a treatment that leads to the development of epilepsy. Brain sections were rendered translucent so that entire hippocampi could be reconstructed and all fluorescently labeled cells identified. Our findings reveal that a small number of progenitors produce the majority of ectopic cells following status epilepticus, indicating that either the affected progenitors or their local microenvironments have become pathological. By contrast, granule cells with “basal” dendrites were equally distributed among clonal groups. This indicates that these progenitors can produce normal cells and suggests that global factors sporadically disrupt the dendritic development of some new cells. Together, these findings strongly predict that distinct mechanisms regulate different aspects of granule cell pathology in epilepsy. PMID:26756038

Bacillus subtilis Swarmer Cells Lead the Swarm, Multiply, and Generate a Trail of Quiescent Descendants.

PubMed

Hamouche, Lina; Laalami, Soumaya; Daerr, Adrian; Song, Solène; Holland, I Barry; Séror, Simone J; Hamze, Kassem; Putzer, Harald

2017-02-07

Bacteria adopt social behavior to expand into new territory, led by specialized swarmers, before forming a biofilm. Such mass migration of Bacillus subtilis on a synthetic medium produces hyperbranching dendrites that transiently (equivalent to 4 to 5 generations of growth) maintain a cellular monolayer over long distances, greatly facilitating single-cell gene expression analysis. Paradoxically, while cells in the dendrites (nonswarmers) might be expected to grow exponentially, the rate of swarm expansion is constant, suggesting that some cells are not multiplying. Little attention has been paid to which cells in a swarm are actually multiplying and contributing to the overall biomass. Here, we show in situ that DNA replication, protein translation and peptidoglycan synthesis are primarily restricted to the swarmer cells at dendrite tips. Thus, these specialized cells not only lead the population forward but are apparently the source of all cells in the stems of early dendrites. We developed a simple mathematical model that supports this conclusion. Swarming motility enables rapid coordinated surface translocation of a microbial community, preceding the formation of a biofilm. This movement occurs in thin films and involves specialized swarmer cells localized to a narrow zone at the extreme swarm edge. In the B. subtilis system, using a synthetic medium, the swarm front remains as a cellular monolayer for up to 1.5 cm. Swarmers display high-velocity whirls and vortexing and are often assumed to drive community expansion at the expense of cell growth. Surprisingly, little attention has been paid to which cells in a swarm are actually growing and contributing to the overall biomass. Here, we show that swarmers not only lead the population forward but continue to multiply as a source of all cells in the community. We present a model that explains how exponential growth of only a few cells is compatible with the linear expansion rate of the swarm. Copyright © 2017 Hamouche et al.

Activation of glial FGFRs is essential in glial migration, proliferation, and survival and in glia-neuron signaling during olfactory system development.

PubMed

Gibson, Nicholas J; Tolbert, Leslie P; Oland, Lynne A

2012-01-01

Development of the adult olfactory system of the moth Manduca sexta depends on reciprocal interactions between olfactory receptor neuron (ORN) axons growing in from the periphery and centrally-derived glial cells. Early-arriving ORN axons induce a subset of glial cells to proliferate and migrate to form an axon-sorting zone, in which later-arriving ORN axons will change their axonal neighbors and change their direction of outgrowth in order to travel with like axons to their target areas in the olfactory (antennal) lobe. These newly fasciculated axon bundles will terminate in protoglomeruli, the formation of which induces other glial cells to migrate to surround them. Glial cells do not migrate unless ORN axons are present, axons fail to fasciculate and target correctly without sufficient glial cells, and protoglomeruli are not maintained without a glial surround. We have shown previously that Epidermal Growth Factor receptors and the IgCAMs Neuroglian and Fasciclin II play a role in the ORN responses to glial cells. In the present work, we present evidence for the importance of glial Fibroblast Growth Factor receptors in glial migration, proliferation, and survival in this developing pathway. We also report changes in growth patterns of ORN axons and of the dendrites of olfactory (antennal lobe) neurons following blockade of glial FGFR activation that suggest that glial FGFR activation is important in reciprocal communication between neurons and glial cells.

Activation of Glial FGFRs Is Essential in Glial Migration, Proliferation, and Survival and in Glia-Neuron Signaling during Olfactory System Development

PubMed Central

Gibson, Nicholas J.; Tolbert, Leslie P.; Oland, Lynne A.

2012-01-01

Development of the adult olfactory system of the moth Manduca sexta depends on reciprocal interactions between olfactory receptor neuron (ORN) axons growing in from the periphery and centrally-derived glial cells. Early-arriving ORN axons induce a subset of glial cells to proliferate and migrate to form an axon-sorting zone, in which later-arriving ORN axons will change their axonal neighbors and change their direction of outgrowth in order to travel with like axons to their target areas in the olfactory (antennal) lobe. These newly fasciculated axon bundles will terminate in protoglomeruli, the formation of which induces other glial cells to migrate to surround them. Glial cells do not migrate unless ORN axons are present, axons fail to fasciculate and target correctly without sufficient glial cells, and protoglomeruli are not maintained without a glial surround. We have shown previously that Epidermal Growth Factor receptors and the IgCAMs Neuroglian and Fasciclin II play a role in the ORN responses to glial cells. In the present work, we present evidence for the importance of glial Fibroblast Growth Factor receptors in glial migration, proliferation, and survival in this developing pathway. We also report changes in growth patterns of ORN axons and of the dendrites of olfactory (antennal lobe) neurons following blockade of glial FGFR activation that suggest that glial FGFR activation is important in reciprocal communication between neurons and glial cells. PMID:22493675

Linking innate to adaptive immunity through dendritic cells.

PubMed

Steinman, Ralph M

2006-01-01

The function of dendritic cells (DCs) in linking innate to adaptive immunity is often summarized with two terms. DCs are sentinels, able to capture, process and present antigens and to migrate to lymphoid tissues to select rare, antigen-reactive T cell clones. DCs are also sensors, responding to a spectrum of environmental cues by extensive differentiation or maturation. The type of DC and the type of maturation induced by different stimuli influences the immunological outcome, such as the differentiation of Thl vs. Th2 T cells. Here we summarize the contributions of DCs to innate defences, particularly the production of immune enhancing cytokines and the activation of innate lymphocytes. Then we outline three innate features of DCs that influence peripheral tolerance and lead to adaptive immunity: a specialized endocytic system for antigen capture and processing, location and movements in vivo, and maturation in response to an array of stimuli. A new approach to the analysis of DC biology is to target antigens selectively to maturing DCs in vivo. This leads to stronger, more prolonged and broader (many immunogenic peptides) immunity by both T cells and B cells.

Tetanus toxoid and CCL3 improve dendritic cell vaccines in mice and glioblastoma patients.

PubMed

Mitchell, Duane A; Batich, Kristen A; Gunn, Michael D; Huang, Min-Nung; Sanchez-Perez, Luis; Nair, Smita K; Congdon, Kendra L; Reap, Elizabeth A; Archer, Gary E; Desjardins, Annick; Friedman, Allan H; Friedman, Henry S; Herndon, James E; Coan, April; McLendon, Roger E; Reardon, David A; Vredenburgh, James J; Bigner, Darell D; Sampson, John H

2015-03-19

After stimulation, dendritic cells (DCs) mature and migrate to draining lymph nodes to induce immune responses. As such, autologous DCs generated ex vivo have been pulsed with tumour antigens and injected back into patients as immunotherapy. While DC vaccines have shown limited promise in the treatment of patients with advanced cancers including glioblastoma, the factors dictating DC vaccine efficacy remain poorly understood. Here we show that pre-conditioning the vaccine site with a potent recall antigen such as tetanus/diphtheria (Td) toxoid can significantly improve the lymph node homing and efficacy of tumour-antigen-specific DCs. To assess the effect of vaccine site pre-conditioning in humans, we randomized patients with glioblastoma to pre-conditioning with either mature DCs or Td unilaterally before bilateral vaccination with DCs pulsed with Cytomegalovirus phosphoprotein 65 (pp65) RNA. We and other laboratories have shown that pp65 is expressed in more than 90% of glioblastoma specimens but not in surrounding normal brain, providing an unparalleled opportunity to subvert this viral protein as a tumour-specific target. Patients given Td had enhanced DC migration bilaterally and significantly improved survival. In mice, Td pre-conditioning also enhanced bilateral DC migration and suppressed tumour growth in a manner dependent on the chemokine CCL3. Our clinical studies and corroborating investigations in mice suggest that pre-conditioning with a potent recall antigen may represent a viable strategy to improve anti-tumour immunotherapy.

Multiplex Analysis of Serum Cytokines in Humans with Hantavirus Pulmonary Syndrome.

PubMed

Morzunov, Sergey P; Khaiboullina, Svetlana F; St Jeor, Stephen; Rizvanov, Albert A; Lombardi, Vincent C

2015-01-01

Hantavirus pulmonary syndrome (HPS) is an acute zoonotic disease transmitted primarily through inhalation of virus-contaminated aerosols. Hantavirus infection of endothelial cells leads to increased vascular permeability without a visible cytopathic effect. For this reason, it has been suggested that the pathogenesis of HPS is indirect with immune responses, such as cytokine production, playing a dominant role. In order to investigate their potential contribution to HPS pathogenesis, we analyzed the serum of hantavirus-infected subjects and healthy controls for 68 different cytokines, chemokines, angiogenic, and growth factors. Our analysis identified differential expression of cytokines that promote tissue migration of mononuclear cells including T lymphocytes, natural killer cells, and dendritic cells. Additionally, we observed a significant upregulation of cytokines known to regulate leukocyte migration and subsequent repair of lung tissue, as well as cytokines known to increase endothelial monolayer permeability and facilitate leukocyte transendothelial migration. Conversely, we observed a downregulation of cytokines associated with platelet numbers and function, consistent with the thrombocytopenia observed in subjects with HPS. This study corroborates clinical findings and extends our current knowledge regarding immunological and laboratory findings in subjects with HPS.

A reverse signaling pathway downstream of Sema4A controls cell migration via Scrib

PubMed Central

Yang, Lida; Kaur, Harmandeep; Pestel, Jenny; Looso, Mario; Nolte, Hendrik; Krishnan, Ramesh K.; Bünemann, Moritz; Offermanns, Stefan; Swiercz, Jakub M.

2017-01-01

Semaphorins comprise a large family of ligands that regulate key cellular functions through their receptors, plexins. In this study, we show that the transmembrane semaphorin 4A (Sema4A) can also function as a receptor, rather than a ligand, and transduce signals triggered by the binding of Plexin-B1 through reverse signaling. Functionally, reverse Sema4A signaling regulates the migration of various cancer cells as well as dendritic cells. By combining mass spectrometry analysis with small interfering RNA screening, we identify the polarity protein Scrib as a downstream effector of Sema4A. We further show that binding of Plexin-B1 to Sema4A promotes the interaction of Sema4A with Scrib, thereby removing Scrib from its complex with the Rac/Cdc42 exchange factor βPIX and decreasing the activity of the small guanosine triphosphatase Rac1 and Cdc42. Our data unravel a role for Plexin-B1 as a ligand and Sema4A as a receptor and characterize a reverse signaling pathway downstream of Sema4A, which controls cell migration. PMID:28007914

3D Microfluidic model for evaluating immunotherapy efficacy by tracking dendritic cell behaviour toward tumor cells.

PubMed

Parlato, Stefania; De Ninno, Adele; Molfetta, Rosa; Toschi, Elena; Salerno, Debora; Mencattini, Arianna; Romagnoli, Giulia; Fragale, Alessandra; Roccazzello, Lorenzo; Buoncervello, Maria; Canini, Irene; Bentivegna, Enrico; Falchi, Mario; Bertani, Francesca Romana; Gerardino, Annamaria; Martinelli, Eugenio; Natale, Corrado; Paolini, Rossella; Businaro, Luca; Gabriele, Lucia

2017-04-24

Immunotherapy efficacy relies on the crosstalk within the tumor microenvironment between cancer and dendritic cells (DCs) resulting in the induction of a potent and effective antitumor response. DCs have the specific role of recognizing cancer cells, taking up tumor antigens (Ags) and then migrating to lymph nodes for Ag (cross)-presentation to naïve T cells. Interferon-α-conditioned DCs (IFN-DCs) exhibit marked phagocytic activity and the special ability of inducing Ag-specific T-cell response. Here, we have developed a novel microfluidic platform recreating tightly interconnected cancer and immune systems with specific 3D environmental properties, for tracking human DC behaviour toward tumor cells. By combining our microfluidic platform with advanced microscopy and a revised cell tracking analysis algorithm, it was possible to evaluate the guided efficient motion of IFN-DCs toward drug-treated cancer cells and the succeeding phagocytosis events. Overall, this platform allowed the dissection of IFN-DC-cancer cell interactions within 3D tumor spaces, with the discovery of major underlying factors such as CXCR4 involvement and underscored its potential as an innovative tool to assess the efficacy of immunotherapeutic approaches.

A translocated effector required for Bartonella dissemination from derma to blood safeguards migratory host cells from damage by co-translocated effectors.

PubMed

Okujava, Rusudan; Guye, Patrick; Lu, Yun-Yueh; Mistl, Claudia; Polus, Florine; Vayssier-Taussat, Muriel; Halin, Cornelia; Rolink, Antonius G; Dehio, Christoph

2014-06-01

Numerous bacterial pathogens secrete multiple effectors to modulate host cellular functions. These effectors may interfere with each other to efficiently control the infection process. Bartonellae are Gram-negative, facultative intracellular bacteria using a VirB type IV secretion system to translocate a cocktail of Bartonella effector proteins (Beps) into host cells. Based on in vitro infection models we demonstrate here that BepE protects infected migratory cells from injurious effects triggered by BepC and is required for in vivo dissemination of bacteria from the dermal site of inoculation to blood. Human endothelial cells (HUVECs) infected with a ΔbepE mutant of B. henselae (Bhe) displayed a cell fragmentation phenotype resulting from Bep-dependent disturbance of rear edge detachment during migration. A ΔbepCE mutant did not show cell fragmentation, indicating that BepC is critical for triggering this deleterious phenotype. Complementation of ΔbepE with BepEBhe or its homologues from other Bartonella species abolished cell fragmentation. This cyto-protective activity is confined to the C-terminal Bartonella intracellular delivery (BID) domain of BepEBhe (BID2.EBhe). Ectopic expression of BID2.EBhe impeded the disruption of actin stress fibers by Rho Inhibitor 1, indicating that BepE restores normal cell migration via the RhoA signaling pathway, a major regulator of rear edge retraction. An intradermal (i.d.) model for B. tribocorum (Btr) infection in the rat reservoir host mimicking the natural route of infection by blood sucking arthropods allowed demonstrating a vital role for BepE in bacterial dissemination from derma to blood. While the Btr mutant ΔbepDE was abacteremic following i.d. inoculation, complementation with BepEBtr, BepEBhe or BIDs.EBhe restored bacteremia. Given that we observed a similar protective effect of BepEBhe on infected bone marrow-derived dendritic cells migrating through a monolayer of lymphatic endothelial cells we propose that infected dermal dendritic cells may be involved in disseminating Bartonella towards the blood stream in a BepE-dependent manner.

A Translocated Effector Required for Bartonella Dissemination from Derma to Blood Safeguards Migratory Host Cells from Damage by Co-translocated Effectors

PubMed Central

Okujava, Rusudan; Guye, Patrick; Lu, Yun-Yueh; Mistl, Claudia; Polus, Florine; Vayssier-Taussat, Muriel; Halin, Cornelia; Rolink, Antonius G.; Dehio, Christoph

2014-01-01

Numerous bacterial pathogens secrete multiple effectors to modulate host cellular functions. These effectors may interfere with each other to efficiently control the infection process. Bartonellae are Gram-negative, facultative intracellular bacteria using a VirB type IV secretion system to translocate a cocktail of Bartonella effector proteins (Beps) into host cells. Based on in vitro infection models we demonstrate here that BepE protects infected migratory cells from injurious effects triggered by BepC and is required for in vivo dissemination of bacteria from the dermal site of inoculation to blood. Human endothelial cells (HUVECs) infected with a ΔbepE mutant of B. henselae (Bhe) displayed a cell fragmentation phenotype resulting from Bep-dependent disturbance of rear edge detachment during migration. A ΔbepCE mutant did not show cell fragmentation, indicating that BepC is critical for triggering this deleterious phenotype. Complementation of ΔbepE with BepEBhe or its homologues from other Bartonella species abolished cell fragmentation. This cyto-protective activity is confined to the C-terminal Bartonella intracellular delivery (BID) domain of BepEBhe (BID2.EBhe). Ectopic expression of BID2.EBhe impeded the disruption of actin stress fibers by Rho Inhibitor 1, indicating that BepE restores normal cell migration via the RhoA signaling pathway, a major regulator of rear edge retraction. An intradermal (i.d.) model for B. tribocorum (Btr) infection in the rat reservoir host mimicking the natural route of infection by blood sucking arthropods allowed demonstrating a vital role for BepE in bacterial dissemination from derma to blood. While the Btr mutant ΔbepDE was abacteremic following i.d. inoculation, complementation with BepEBtr, BepEBhe or BIDs.EBhe restored bacteremia. Given that we observed a similar protective effect of BepEBhe on infected bone marrow-derived dendritic cells migrating through a monolayer of lymphatic endothelial cells we propose that infected dermal dendritic cells may be involved in disseminating Bartonella towards the blood stream in a BepE-dependent manner. PMID:24945914

Ursodeoxycholic acid suppresses eosinophilic airway inflammation by inhibiting the function of dendritic cells through the nuclear farnesoid X receptor.

PubMed

Willart, M A M; van Nimwegen, M; Grefhorst, A; Hammad, H; Moons, L; Hoogsteden, H C; Lambrecht, B N; Kleinjan, A

2012-12-01

Ursodeoxycholic acid (UDCA) is the only known beneficial bile acid with immunomodulatory properties. Ursodeoxycholic acid prevents eosinophilic degranulation and reduces eosinophil counts in primary biliary cirrhosis. It is unknown whether UDCA would also modulate eosinophilic inflammation outside the gastrointestinal (GI) tract, such as eosinophilic airway inflammation seen in asthma. The working mechanism for its immunomodulatory effect is unknown. The immunosuppressive features of UDCA were studied in vivo, in mice, in an ovalbumin (OVA)-driven eosinophilic airway inflammation model. To study the mechanism of action of UDCA, we analyzed the effect of UDCA on eosinophils, T cells, and dendritic cell (DCs). DC function was studied in greater detail, focussing on migration and T-cell stimulatory strength in vivo and interaction with T cells in vitro as measured by time-lapse image analysis. Finally, we studied the capacity of UDCA to influence DC/T cell interaction. Ursodeoxycholic acid treatment of OVA-sensitized mice prior to OVA aerosol challenge significantly reduced eosinophilic airway inflammation compared with control animals. DCs expressed the farnesoid X receptor for UDCA. Ursodeoxycholic acid strongly promoted interleukin (IL)-12 production and enhanced the migration in DCs. The time of interaction between DCs and T cells was sharply reduced in vitro by UDCA treatment of the DCs resulting in a remarkable T-cell cytokine production. Ursodeoxycholic acid-treated DCs have less capacity than saline-treated DCs to induce eosinophilic inflammation in vivo in Balb/c mice. Ursodeoxycholic acid has the potency to suppress eosinophilic inflammation outside the GI tract. This potential comprises to alter critical function of DCs, in essence, the effect of UDCA on DCs through the modulation of the DC/T cell interaction. © 2012 John Wiley & Sons A/S.

Stress-Induced Neurogenic Inflammation in Murine Skin Skews Dendritic Cells Towards Maturation and Migration

PubMed Central

Joachim, Ricarda Alcira; Handjiski, Bori; Blois, Sandra Maria; Hagen, Evelin; Paus, Ralf; Arck, Petra Clara

2008-01-01

The skin continuously serves as a biosensor of multiple exogenous stressors and integrates the resulting responses with an individual’s central and peripheral endogenous response systems to perceived stress; it also acts to protect against external challenges such as wounding and infection. We have previously shown in mice that stress induces nerve growth factor- and substance P-dependent neurogenic inflammation, which includes the prominent clustering of MHC class II+ cells. Because the contribution of dendritic cells (DCs) in response to stress is not well understood, we examined the role of DCs in neurogenic inflammation in murine skin using a well-established murine stress model. We show that sound stress increases the number of intradermal langerin+ and CD11c+ DCs and induces DC maturation, as indicated by the up-regulated expression of CD11c, MHC class II, and intercellular adhesion molecule-1 (ICAM-1). Blocking of ICAM-1/leukocyte function-associated antigen-1 interactions significantly abrogated the stress-induced numeric increase, maturation, and migration of dermal DCs in vivo and also reduced stress-induced keratinocyte apoptosis and endothelial cell expression of ICAM-1. In conclusion, stress exposure causes a state of immune alertness in the skin. Such adaptation processes may ensure protection from possible infections on wounding by stressors, such as attack by predators. However, present-day stressors have changed and such adaptations appear redundant and may overrun skin homeostasis by inducing immune dermatoses. PMID:18832583

Neutrophils and monocytes transport tumor cell antigens from the peritoneal cavity to secondary lymphoid tissues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Terasawa, Masao; Nagata, Kisaburo; Kobayashi, Yoshiro

2008-12-12

Antigen-transporting cells take up pathogens, and then migrate from sites of inflammation to secondary lymphoid tissues to induce an immune response. Among antigen-transporting cells, dendritic cells (DCs) are believed to be the most potent and professional antigen-presenting cells that can stimulate naive T cells. However, the cells that transport antigens, tumor cell antigens in particular, have not been clearly identified. In this study we have analyzed what types of cells transport tumor cell antigens to secondary lymphoid tissues. We show that neutrophils, monocytes and macrophages but not DCs engulf X-irradiated P388 leukemic cells after their injection into the peritoneal cavity,more » and that neutrophils and monocytes but not macrophages migrate to the parathymic lymph nodes (pLN), the blood, and then the spleen. The monocytes in the pLN comprise Gr-1{sup -} and Gr-1{sup +} ones, and some of these cells express CD11c. Overall, this study demonstrates that neutrophils and monocytes transport tumor cell antigens from the peritoneal cavity to secondary lymphoid tissues.« less

To the Brain and Back: Migratory Paths of Dendritic Cells in Multiple Sclerosis.

PubMed

De Laere, Maxime; Berneman, Zwi N; Cools, Nathalie

2018-03-01

Migration of dendritic cells (DC) to the central nervous system (CNS) is a critical event in the pathogenesis of multiple sclerosis (MS). While up until now, research has mainly focused on the transmigration of DC through the blood-brain barrier, experimental evidence points out that also the choroid plexus and meningeal vessels represent important gateways to the CNS, especially in early disease stages. On the other hand, DC can exit the CNS to maintain immunological tolerance to patterns expressed in the CNS, a process that is perturbed in MS. Targeting trafficking of immune cells, including DC, to the CNS has demonstrated to be a successful strategy to treat MS. However, this approach is known to compromise protective immune surveillance of the brain. Unravelling the migratory paths of regulatory and pathogenic DC within the CNS may ultimately lead to the design of new therapeutic strategies able to selectively interfere with the recruitment of pathogenic DC to the CNS, while leaving host protective mechanisms intact. © 2018 American Association of Neuropathologists, Inc.

Plant microRNAs as novel immunomodulatory agents

PubMed Central

Cavalieri, Duccio; Rizzetto, Lisa; Tocci, Noemi; Rivero, Damariz; Asquini, Elisa; Si-Ammour, Azeddine; Bonechi, Elena; Ballerini, Clara; Viola, Roberto

2016-01-01

An increasing body of literature is addressing the immuno-modulating functions of miRNAs which include paracrine signaling via exosome-mediated intercellular miRNA. In view of the recent evidence of intake and bioavailability of dietary miRNAs in humans and animals we explored the immuno-modulating capacity of plant derived miRNAs. Here we show that transfection of synthetic miRNAs or native miRNA-enriched fractions obtained from a wide range of plant species and organs modifies dendritic cells ability to respond to inflammatory agents by limiting T cell proliferation and consequently dampening inflammation. This immuno-modulatory effect appears associated with binding of plant miRNA on TLR3 with ensuing impairment of TRIF signaling. Similarly, in vivo, plant small RNAs reduce the onset of severity of Experimental Autoimmune Encephalomyelities by limiting dendritic cell migration and dampening Th1 and Th17 responses in a Treg-independent manner. Our results indicate a potential for therapeutic use of plant miRNAs in the prevention of chronic-inflammation related diseases. PMID:27167363

Mesenteric Lymph Nodes Confine Dendritic Cell-Mediated Dissemination of Salmonella enterica Serovar Typhimurium and Limit Systemic Disease in Mice▿

PubMed Central

Voedisch, Sabrina; Koenecke, Christian; David, Sascha; Herbrand, Heike; Förster, Reinhold; Rhen, Mikael; Pabst, Oliver

2009-01-01

In humans with typhoid fever or in mouse strains susceptible to Salmonella enterica serovar Typhimurium (S. Typhimurium) infection, bacteria gain access to extraintestinal tissues, causing severe systemic disease. Here we show that in the gut-draining mesenteric lymph nodes (MLN), the majority of S. Typhimurium-carrying cells show dendritic-cell (DC) morphology and express the DC marker CD11c, indicating that S. Typhimurium bacteria are transported to the MLN by migratory DCs. In vivo FLT-3L-induced expansion of DCs, as well as stimulation of DC migration by Toll-like receptor agonists, results in increased numbers of S. Typhimurium bacteria reaching the MLN. Conversely, genetically impaired DC migration in chemokine receptor CCR7-deficient mice reduces the number of S. Typhimurium bacteria reaching the MLN. This indicates that transport of S. Typhimurium from the intestine into the MLN is limited by the number of migratory DCs carrying S. Typhimurium bacteria. In contrast, modulation of DC migration does not affect the number of S. Typhimurium bacteria reaching systemic tissues, indicating that DC-bound transport of S. Typhimurium does not substantially contribute to systemic S. Typhimurium infection. Surgical removal of the MLN results in increased numbers of S. Typhimurium bacteria reaching systemic sites early after infection, thereby rendering otherwise resistant mice susceptible to fatal systemic disease development. This suggests that the MLN provide a vital barrier shielding systemic compartments from DC-mediated dissemination of S. Typhimurium. Thus, confinement of S. Typhimurium in gut-associated lymphoid tissue and MLN delays massive extraintestinal dissemination and at the same time allows for the establishment of protective adaptive immune responses. PMID:19506012

A short protocol using dexamethasone and monophosphoryl lipid A generates tolerogenic dendritic cells that display a potent migratory capacity to lymphoid chemokines

PubMed Central

2013-01-01

Background Generation of tolerogenic dendritic cells (TolDCs) for therapy is challenging due to its implications for the design of protocols suitable for clinical applications, which means not only using safe products, but also working at defining specific biomarkers for TolDCs identification, developing shorter DCs differentiation methods and obtaining TolDCs with a stable phenotype. We describe here, a short-term protocol for TolDCs generation, which are characterized in terms of phenotypic markers, cytokines secretion profile, CD4+ T cell-stimulatory ability and migratory capacity. Methods TolDCs from healthy donors were generated by modulation with dexamethasone plus monophosphoryl lipid A (MPLA-tDCs). We performed an analysis of MPLA-tDCs in terms of yield, viability, morphology, phenotypic markers, cytokines secretion profile, stability, allogeneic and antigen-specific CD4+ T-cell stimulatory ability and migration capacity. Results After a 5-day culture, MPLA-tDCs displayed reduced expression of costimulatory and maturation molecules together to an anti-inflammatory cytokines secretion profile, being able to maintain these tolerogenic features even after the engagement of CD40 by its cognate ligand. In addition, MPLA-tDCs exhibited reduced capabilities to stimulate allogeneic and antigen-specific CD4+ T cell proliferation, and induced an anti-inflammatory cytokine secretion pattern. Among potential tolerogenic markers studied, only TLR-2 was highly expressed in MPLA-tDCs when compared to mature and immature DCs. Remarkable, like mature DCs, MPLA-tDCs displayed a high CCR7 and CXCR4 expression, both chemokine receptors involved in migration to secondary lymphoid organs, and even more, in an in vitro assay they exhibited a high migration response towards CCL19 and CXCL12. Conclusion We describe a short-term protocol for TolDC generation, which confers them a stable phenotype and migratory capacity to lymphoid chemokines, essential features for TolDCs to be used as therapeutics for autoimmunity and prevention of graft rejection. PMID:23706017

Dendritic polyglycerol sulfates as multivalent inhibitors of inflammation.

PubMed

Dernedde, Jens; Rausch, Alexandra; Weinhart, Marie; Enders, Sven; Tauber, Rudolf; Licha, Kai; Schirner, Michael; Zügel, Ulrich; von Bonin, Arne; Haag, Rainer

2010-11-16

Adhesive interactions of leukocytes and endothelial cells initiate leukocyte migration to inflamed tissue and are important for immune surveillance. Acute and chronic inflammatory diseases show a dysregulated immune response and result in a massive efflux of leukocytes that contributes to further tissue damage. Therefore, targeting leukocyte trafficking may provide a potent form of anti-inflammatory therapy. Leukocyte migration is initiated by interactions of the cell adhesion molecules E-, L-, and P-selectin and their corresponding carbohydrate ligands. Compounds that efficiently address these interactions are therefore of high therapeutic interest. Based on this rationale we investigated synthetic dendritic polyglycerol sulfates (dPGS) as macromolecular inhibitors that operate via a multivalent binding mechanism mimicking naturally occurring ligands. dPGS inhibited both leukocytic L-selectin and endothelial P-selectin with high efficacy. Size and degree of sulfation of the polymer core determined selectin binding affinity. Administration of dPGS in a contact dermatitis mouse model dampened leukocyte extravasation as effectively as glucocorticoids did and edema formation was significantly reduced. In addition, dPGS interacted with the complement factors C3 and C5 as was shown in vitro and reduced C5a levels in a mouse model of complement activation. Thus, dPGS represent an innovative class of a fully synthetic polymer therapeutics that may be used for the treatment of inflammatory diseases.

Dendritic polyglycerol sulfates as multivalent inhibitors of inflammation

PubMed Central

Dernedde, Jens; Rausch, Alexandra; Weinhart, Marie; Enders, Sven; Tauber, Rudolf; Licha, Kai; Schirner, Michael; Zügel, Ulrich; von Bonin, Arne; Haag, Rainer

2010-01-01

Adhesive interactions of leukocytes and endothelial cells initiate leukocyte migration to inflamed tissue and are important for immune surveillance. Acute and chronic inflammatory diseases show a dysregulated immune response and result in a massive efflux of leukocytes that contributes to further tissue damage. Therefore, targeting leukocyte trafficking may provide a potent form of anti-inflammatory therapy. Leukocyte migration is initiated by interactions of the cell adhesion molecules E-, L-, and P-selectin and their corresponding carbohydrate ligands. Compounds that efficiently address these interactions are therefore of high therapeutic interest. Based on this rationale we investigated synthetic dendritic polyglycerol sulfates (dPGS) as macromolecular inhibitors that operate via a multivalent binding mechanism mimicking naturally occurring ligands. dPGS inhibited both leukocytic L-selectin and endothelial P-selectin with high efficacy. Size and degree of sulfation of the polymer core determined selectin binding affinity. Administration of dPGS in a contact dermatitis mouse model dampened leukocyte extravasation as effectively as glucocorticoids did and edema formation was significantly reduced. In addition, dPGS interacted with the complement factors C3 and C5 as was shown in vitro and reduced C5a levels in a mouse model of complement activation. Thus, dPGS represent an innovative class of a fully synthetic polymer therapeutics that may be used for the treatment of inflammatory diseases. PMID:21041668

Inhibition of allergic bronchial asthma by thrombomodulin is mediated by dendritic cells.

PubMed

Takagi, Takehiro; Taguchi, Osamu; Toda, Masaaki; Ruiz, Daniel Boveda; Bernabe, Paloma Gil; D'Alessandro-Gabazza, Corina N; Miyake, Yasushi; Kobayashi, Tetsu; Aoki, Shinya; Chiba, Fumiko; Yano, Yutaka; Conway, Edward M; Munesue, Seiichi; Yamamoto, Yasuhiko; Yamamoto, Hiroshi; Suzuki, Koji; Takei, Yoshiyuki; Morser, John; Gabazza, Esteban C

2011-01-01

bronchial asthma is caused by inappropriate acquired immune responses to environmental allergens. It is a major health problem, with a prevalence that is rapidly increasing. Curative therapy is not currently available. to test the hypothesis that thrombomodulin (TM) inhibits allergic bronchial asthma by inducing tolerogenic dendritic cells (DCs). the protective effect of TM was evaluated using a murine asthma model. Asthma was induced in mice by exposure to chicken egg ovalbumin, and the effects of inhaled TM or TM-treated DCs were assessed by administering before ovalbumin exposure. treatment with TM protects against bronchial asthma measured as improved lung function and reduced IgE and cells in alveolar lavage fluid by inducing tolerogenic dendritic dells. These are characterized by high expression of surface TM (CD141/TM(+)) and low expression of maturation markers and possess reduced T-cell costimulatory activity. The CD141/TM(+) DCs migrate less toward chemokines, and after TM treatment there are fewer DCs in the draining lymph node and more in the lungs. The TM effect is independent of its role in coagulation. Rather, it is mediated via the TM lectin domain directly interacting with the DCs. the results of this study show that TM is a modulator of DC immunostimulatory properties and a novel candidate drug for the prevention of bronchial asthma in atopic patients.

Expression of chemokine CXCL10 in dendritic-cell-like S100β-positive cells in rat anterior pituitary gland.

PubMed

Horiguchi, Kotaro; Fujiwara, Ken; Higuchi, Masashi; Yoshida, Saishu; Tsukada, Takehiro; Ueharu, Hiroki; Chen, Mo; Hasegawa, Rumi; Takigami, Shu; Ohsako, Shunji; Yashiro, Takashi; Kato, Takako; Kato, Yukio

2014-09-01

Chemokines are mostly small secreted polypeptides whose signals are mediated by seven trans-membrane G-protein-coupled receptors. Their functions include the control of leukocytes and the intercellular mediation of cell migration, proliferation, and adhesion in several tissues. We have previously revealed that the CXC chemokine ligand 12 (CXCL12) and its receptor 4 (CXCR4) are expressed in the anterior pituitary gland, and that the CXCL12/CXCR4 axis evokes the migration and interconnection of S100β-protein-positive cells (S100β-positive cells), which do not produce classical anterior pituitary hormones. However, little is known of the cells producing the other CXCLs and CXCRs or of their characteristics in the anterior pituitary. We therefore examined whether CXCLs and CXCRs occurred in the rat anterior pituitary lobe. We used reverse transcription plus the polymerase chain reaction to analyze the expression of Cxcl and Cxcr and identified the cells that expressed Cxcl by in situ hybridization. Transcripts of Cxcl10 and its receptor (Cxcr3 and toll-like receptor 4, Tlr4) were clearly detected: cells expressing Cxcl10 and Tlr4 were identified amongst S100β-positive cells and those expressing Cxcr3 amongst adrenocorticotropic hormone (ACTH)-producing cells. We also investigated Cxcl10 expression in subpopulations of S100β-positive cells. We separated cultured S100β-positive cells into the round-type (dendritic-cell-like) and process-type (astrocyte- or epithelial-cell-like) by their adherent activity to laminin, a component of the extracellular matrix; CXCL10 was expressed only in round-type S100β-positive cells. Thus, CXCL10 produced by a subpopulation of S100β-positive cells probably exerts an autocrine/paracrine effect on S100β-positive cells and ACTH-producing cells in the anterior lobe.

Resolvin E1 inhibits dendritic cell migration in the skin and attenuates contact hypersensitivity responses

PubMed Central

Sawada, Yu; Hanakawa, Sho; Nakamizo, Satoshi; Murata, Teruasa; Ueharaguchi-Tanada, Yuri; Ono, Sachiko; Amano, Wataru; Nakajima, Saeko; Egawa, Gyohei; Tanizaki, Hideaki; Otsuka, Atsushi; Kitoh, Akihiko; Dainichi, Teruki; Ogawa, Narihito; Kobayashi, Yuichi; Yokomizo, Takehiko; Arita, Makoto; Nakamura, Motonobu; Miyachi, Yoshiki

2015-01-01

Resolvin E1 (RvE1) is a lipid mediator derived from ω3 polyunsaturated fatty acids that exerts potent antiinflammatory roles in several murine models. The antiinflammatory mechanism of RvE1 in acquired immune responses has been attributed to attenuation of cytokine production by dendritic cells (DCs). In this study, we newly investigated the effect of RvE1 on DC motility using two-photon microscopy in a contact hypersensitivity (CHS) model and found that RvE1 impaired DC motility in the skin. In addition, RvE1 attenuated T cell priming in the draining lymph nodes and effector T cell activation in the skin, which led to the reduced skin inflammation in CHS. In contrast, leukotriene B4 (LTB4) induced actin filament reorganization in DCs and increased DC motility by activating Cdc42 and Rac1 via BLT1, which was abrogated by RvE1. Collectively, our results suggest that RvE1 attenuates cutaneous acquired immune responses by inhibiting cutaneous DC motility, possibly through LTB4-BLT1 signaling blockade. PMID:26438363

Prostanoids and their receptors that modulate dendritic cell-mediated immunity.

PubMed

Gualde, Norbert; Harizi, Hedi

2004-08-01

Dendritic cells (DC) are essential for the initiation of immune responses by capturing, processing and presenting antigens to T cells. In addition to their important role as professional APC, they are able to produce immunosuppressive and pro-inflammatory prostanoids from arachidonic acid (AA) by the action of cyclooxygenase (COX) enzymes. In an autocrine and paracrine fashion, the secreted lipid mediators subsequently modulate the maturation, cytokine production, Th-cell polarizing ability, chemokine receptor expression, migration, and apoptosis of these extremely versatile APC. The biological actions of prostanoids, including their effects on APC-mediated immunity and acute inflammatory responses, are exerted by G protein-coupled receptors on plasma membrane. Some COX metabolites act as anti-inflammatory lipid mediators by binding to nuclear receptors and modulating DC functions. Although the role of cytokines in DC function has been studied extensively, the effects of prostanoids on DC biology have only recently become the focus of investigation. This review summarizes the current knowledge about the role of prostanoids and their receptors in modulating DC function and the subsequent immune responses.

Eicosanoids: an emerging role in dendritic cell biology.

PubMed

Harizi, Hedi; Gualde, Norbert

2004-01-01

The arachidonic acid (AA)-derived metabolites, termed eicosanoids, are potent lipid mediators with a key role in immune and inflammatory responses. In the immune system, eicosanoids such as prostaglandins (PGs) and leukotrienes (LTs) are produced predominately by antigen-presenting cells (APC), including macrophages and dendritic cells (DC). DC constitute a family of bone marrow-derived professional APC that play a critical role in the induction and modulation of both innate and adaptive immunity. For many years, macrophages were considered as major producers of eicosanoids that are thought to drastically affect their function. Studies concerning the modulation of DC biology by eicosanoids show that PGs and LTs have the potential to affect the maturation, cytokine-producing capacity, Th cell-polarizing ability, and migration of DC. In addition, the development of DC from bone marrow progenitors appears to be under the control of some eicosanoids. Understanding the actions of eicosanoids and their receptors on APC functions is crucial for the generation of efficient DC for therapeutic purposes in patients. In this review, we summarize the current understanding of how DC functions are modulated by eicosanoids.

Rapamycin increases RSV RNA levels and survival of RSV-infected dendritic cell depending on T cell contact.

PubMed

do Nascimento de Freitas, Deise; Gassen, Rodrigo Benedetti; Fazolo, Tiago; Souza, Ana Paula Duarte de

2016-10-01

The macrolide rapamycin inhibits mTOR (mechanist target of rapamycin) function and has been broadly used to unveil the role of mTOR in immune responses. Inhibition of mTOR on dendritic cells (DC) can influence cellular immune response and the survival of DC. RSV is the most common cause of hospitalization in infants and is a high priority candidate to vaccine development. In this study we showed that rapamycin treatment on RSV-infected murine bone marrow-derived DC (BMDC) decreases the frequency of CD8(+)CD44(high) T cells. However, inhibition of mTOR on RSV-infected BMDC did not modify the activation phenotype of these cells. RSV-RNA levels increase when infected BMDC were treated with rapamycin. Moreover, we observed that rapamycin diminishes apoptosis cell death of RSV-infected BMDC co-culture with T cells and this effect was abolished when the cells were co-cultured in a transwell system that prevents cell-to-cell contact or migration. Taken together, these data indicate that rapamycin treatment present a toxic effect on RSV-infected BMDC increasing RSV-RNA levels, affecting partially CD8 T cell differentiation and also increasing BMDC survival in a mechanism dependent on T cell contact. Copyright © 2016 Elsevier Ltd. All rights reserved.

Identification of Barramundi (Lates calcarifer) DC-SCRIPT, a Specific Molecular Marker for Dendritic Cells in Fish

PubMed Central

Zoccola, Emmanuelle; Delamare-Deboutteville, Jérôme; Barnes, Andrew C.

2015-01-01

Antigen presentation is a critical step bridging innate immune recognition and specific immune memory. In mammals, the process is orchestrated by dendritic cells (DCs) in the lymphatic system, which initiate clonal proliferation of antigen-specific lymphocytes. However, fish lack a classical lymphatic system and there are currently no cellular markers for DCs in fish, thus antigen-presentation in fish is poorly understood. Recently, antigen-presenting cells similar in structure and function to mammalian DCs were identified in various fish, including rainbow trout (Oncorhynchus mykiss) and zebrafish (Danio rerio). The present study aimed to identify a potential molecular marker for DCs in fish and therefore targeted DC-SCRIPT, a well-conserved zinc finger protein that is preferentially expressed in all sub-types of human DCs. Putative dendritic cells were obtained in culture by maturation of spleen and pronephros-derived monocytes. DC-SCRIPT was identified in barramundi by homology using RACE PCR and genome walking. Specific expression of DC-SCRIPT was detected in barramundi cells by Stellaris mRNA FISH, in combination with MHCII expression when exposed to bacterial derived peptidoglycan, suggesting the presence of DCs in L. calcarifer. Moreover, morphological identification was achieved by light microscopy of cytospins prepared from these cultures. The cultured cells were morphologically similar to mammalian and trout DCs. Migration assays determined that these cells have the ability to move towards pathogens and pathogen associated molecular patterns, with a preference for peptidoglycans over lipopolysaccharides. The cells were also strongly phagocytic, engulfing bacteria and rapidly breaking them down. Barramundi DCs induced significant proliferation of responder populations of T-lymphocytes, supporting their role as antigen presenting cells. DC-SCRIPT expression in head kidney was higher 6 and 24 h following intraperitoneal challenge with peptidoglycan and lipopolysaccharide and declined after 3 days relative to PBS-injected controls. Relative expression was also lower in the spleen at 3 days post challenge but increased again at 7 days. As DC-SCRIPT is a constitutively expressed nuclear receptor, independent of immune activation, this may indicate initial migration of immature DCs from head kidney and spleen to the injection site, followed by return to the spleen for maturation and antigen presentation. DC-SCRIPT may be a valuable tool in the investigation of antigen presentation in fish and facilitate optimisation of vaccines and adjuvants for aquaculture. PMID:26173015

VLA-4 integrin concentrates at the peripheral supramolecular activation complex of the immune synapse and drives T helper 1 responses

NASA Astrophysics Data System (ADS)

Mittelbrunn, María; Molina, Ana; Escribese, María M.; Yáñez-Mó, María; Escudero, Ester; Ursa, Ángeles; Tejedor, Reyes; Mampaso, Francisco; Sánchez-Madrid, Francisco

2004-07-01

The integrin 41 (VLA-4) not only mediates the adhesion and transendothelial migration of leukocytes, but also provides costimulatory signals that contribute to the activation of T lymphocytes. However, the behavior of 41 during the formation of the immune synapse is currently unknown. Here, we show that 41 is recruited to both human and murine antigen-dependent immune synapses, when the antigen-presenting cell is a B lymphocyte or a dendritic cell, colocalizing with LFA-1 at the peripheral supramolecular activation complex. However, when conjugates are formed in the presence of anti-4 antibodies, VLA-4 colocalizes with the CD3- chain at the center of the synapse. In addition, antibody engagement of 4 integrin promotes polarization toward a T helper 1 (Th1) response in human in vitro models of CD4+ T cell differentiation and naïve T cell priming by dendritic cells. The in vivo administration of anti-4 integrin antibodies also induces an immune deviation to Th1 response that dampens a Th2-driven autoimmune nephritis in Brown Norway rats. These data reveal a regulatory role of 4 integrins on T lymphocyte-antigen presenting cell cognate immune interactions.

Dendritic cell reprogramming by endogenously produced lactic acid.

PubMed

Nasi, Aikaterini; Fekete, Tünde; Krishnamurthy, Akilan; Snowden, Stuart; Rajnavölgyi, Eva; Catrina, Anca I; Wheelock, Craig E; Vivar, Nancy; Rethi, Bence

2013-09-15

The demand for controlling T cell responses via dendritic cell (DC) vaccines initiated a quest for reliable and feasible DC modulatory strategies that would facilitate cytotoxicity against tumors or tolerance in autoimmunity. We studied endogenous mechanisms in developing monocyte-derived DCs (MoDCs) that can induce inflammatory or suppressor programs during differentiation, and we identified a powerful autocrine pathway that, in a cell concentration-dependent manner, strongly interferes with inflammatory DC differentiation. MoDCs developing at low cell culture density have superior ability to produce inflammatory cytokines, to induce Th1 polarization, and to migrate toward the lymphoid tissue chemokine CCL19. On the contrary, MoDCs originated from dense cultures produce IL-10 but no inflammatory cytokines upon activation. DCs from high-density cultures maintained more differentiation plasticity and can develop to osteoclasts. The cell concentration-dependent pathway was independent of peroxisome proliferator-activated receptor γ (PPARγ), a known endogenous regulator of MoDC differentiation. Instead, it acted through lactic acid, which accumulated in dense cultures and induced an early and long-lasting reprogramming of MoDC differentiation. Our results suggest that the lactic acid-mediated inhibitory pathway could be efficiently manipulated in developing MoDCs to influence the immunogenicity of DC vaccines.

Age-related guanine nucleotide exchange factor, mouse Zizimin2, induces filopodia in bone marrow-derived dendritic cells

PubMed Central

2012-01-01

Background We recently isolated and identified Zizimin2 as a functional factor that is highly expressed in murine splenic germinal center B cells after immunization with T-cell-dependent antigen. Zizimin2 was revealed to be a new family member of Dock (dedicator of cytokinesis), Dock11, which is the guanine nucleotide exchange factor for Cdc42, a low-molecular-weight GTPase. However, the molecular function of Zizimin2 in acquired immunity has not been elucidated. Results In this study, we show that the protein expression of Zizimin2, which is also restricted to lymphoid tissues and lymphocytes, is reduced in aged mice. Over-expression of full-length Zizimin2 induced filopodial formation in 293T cells, whereas expression of CZH2 domain inhibited it. Stimulation of Fcγ receptor and Toll-like receptor 4 triggered Zizimin2 up-regulation and Cdc42 activation in bone marrow-derived dendritic cells. Conclusions These data suggest that Zizimin2 is an immune-related and age-regulated guanine nucleotide exchange factor, which facilitates filopodial formation through activation of Cdc42, which results in activation of cell migration. PMID:22494997

The Role of Dendritic Cell Maturation in the Induction of Insulin-Dependent Diabetes Mellitus.

PubMed

Mbongue, Jacques C; Nieves, Hector A; Torrez, Timothy W; Langridge, William H R

2017-01-01

Dendritic cells (DCs) are the dominant class of antigen-presenting cells in humans and are largely responsible for the initiation and guidance of innate and adaptive immune responses involved in maintenance of immunological homeostasis. Immature dendritic cells (iDCs) phagocytize pathogens and toxic proteins and in endosomal vesicles degrade them into small fragments for presentation on major histocompatibility complex (MHC) II receptor molecules to naïve cognate T cells (Th0). In addition to their role in stimulation of immunity, DCs are involved in the induction and maintenance of immune tolerance toward self-antigens. During activation, the iDCs become mature. Maturation begins when the DCs cease taking up antigens and begin to migrate from their location in peripheral tissues to adjacent lymph nodes or the spleen where during their continued maturation the DCs present stored antigens on surface MHCII receptor molecules to naive Th0 cells. During antigen presentation, the DCs upregulate the biosynthesis of costimulatory receptor molecules CD86, CD80, CD83, and CD40 on their plasma membrane. These activated DC receptor molecules bind cognate CD28 receptors presented on the Th0 cell membrane, which triggers DC secretion of IL-12 or IL-10 cytokines resulting in T cell differentiation into pro- or anti-inflammatory T cell subsets. Although basic concepts involved in the process of iDC activation and guidance of Th0 cell differentiation have been previously documented, they are poorly defined. In this review, we detail what is known about the process of DC maturation and its role in the induction of insulin-dependent diabetes mellitus autoimmunity.

Dendritic Cells in Kidney Transplant Biopsy Samples Are Associated with T Cell Infiltration and Poor Allograft Survival

PubMed Central

De Serres, Sacha A.; Safa, Kassem; Bijol, Vanesa; Ueno, Takuya; Onozato, Maristela L.; Iafrate, A. John; Herter, Jan M.; Lichtman, Andrew H.; Mayadas, Tanya N.; Guleria, Indira; Rennke, Helmut G.; Najafian, Nader; Chandraker, Anil

2015-01-01

Progress in long-term renal allograft survival continues to lag behind the progress in short-term transplant outcomes. Dendritic cells are the most efficient antigen-presenting cells, but surprisingly little attention has been paid to their presence in transplanted kidneys. We used dendritic cell–specific intercellular adhesion molecule-3–grabbing nonintegrin as a marker of dendritic cells in 105 allograft biopsy samples from 105 kidney transplant recipients. High dendritic cell density was associated with poor allograft survival independent of clinical variables. Moreover, high dendritic cell density correlated with greater T cell proliferation and poor outcomes in patients with high total inflammation scores, including inflammation in areas of tubular atrophy. We then explored the association between dendritic cells and histologic variables associated with poor prognosis. Multivariate analysis revealed an independent association between the densities of dendritic cells and T cells. In biopsy samples with high dendritic cell density, electron microscopy showed direct physical contact between infiltrating lymphocytes and cells that have the ultrastructural morphologic characteristics of dendritic cells. The origin of graft dendritic cells was sought in nine sex-mismatched recipients using XY fluorescence in situ hybridization. Whereas donor dendritic cells predominated initially, the majority of dendritic cells in late allograft biopsy samples were of recipient origin. Our data highlight the prognostic value of dendritic cell density in allograft biopsy samples, suggest a new role for these cells in shaping graft inflammation, and provide a rationale for targeting dendritic cell recruitment to promote long-term allograft survival. PMID:25855773

A reverse signaling pathway downstream of Sema4A controls cell migration via Scrib.

PubMed

Sun, Tianliang; Yang, Lida; Kaur, Harmandeep; Pestel, Jenny; Looso, Mario; Nolte, Hendrik; Krasel, Cornelius; Heil, Daniel; Krishnan, Ramesh K; Santoni, Marie-Josée; Borg, Jean-Paul; Bünemann, Moritz; Offermanns, Stefan; Swiercz, Jakub M; Worzfeld, Thomas

2017-01-02

Semaphorins comprise a large family of ligands that regulate key cellular functions through their receptors, plexins. In this study, we show that the transmembrane semaphorin 4A (Sema4A) can also function as a receptor, rather than a ligand, and transduce signals triggered by the binding of Plexin-B1 through reverse signaling. Functionally, reverse Sema4A signaling regulates the migration of various cancer cells as well as dendritic cells. By combining mass spectrometry analysis with small interfering RNA screening, we identify the polarity protein Scrib as a downstream effector of Sema4A. We further show that binding of Plexin-B1 to Sema4A promotes the interaction of Sema4A with Scrib, thereby removing Scrib from its complex with the Rac/Cdc42 exchange factor βPIX and decreasing the activity of the small guanosine triphosphatase Rac1 and Cdc42. Our data unravel a role for Plexin-B1 as a ligand and Sema4A as a receptor and characterize a reverse signaling pathway downstream of Sema4A, which controls cell migration. © 2017 Sun et al.

Homeostatic migration and distribution of innate immune cells in primary and secondary lymphoid organs with ageing.

PubMed

Nikolich-Žugich, J; Davies, J S

2017-03-01

Ageing of the innate and adaptive immune system, collectively termed immune senescence, is a complex process. One method to understand the components of ageing involves dissociating the effects of ageing on the cells of the immune system, on the microenvironment in lymphoid organs and tissues where immune cells reside and on the circulating factors that interact with both immune cells and their microenvironment. Heterochronic parabiosis, a surgical union of two organisms of disparate ages, is ideal for this type of study, as it has the power to dissociate the age of the cell and the age of the microenvironment into which the cell resides or is migrating. So far, however, it has been used sparingly to study immune ageing. Here we review the limited literature on homeostatic innate immune cell trafficking in ageing in the absence of chronic inflammation. We also review our own recent data on trafficking of innate immune subsets between primary and secondary lymphoid organs in heterochronic parabiosis. We found no systemic bias in retention or acceptance of neutrophils, macrophages, dendritic cells or natural killer cells with ageing in primary and secondary lymphoid organs. We conclude that these four innate immune cell types migrate to and populate lymphoid organs (peripheral lymph nodes, spleen and bone marrow), regardless of their own age and of the age of lymphoid organs. © 2017 British Society for Immunology.

Stimulation of dendritic cells enhances immune response after photodynamic therapy

NASA Astrophysics Data System (ADS)

Mroz, Pawel; Castano, Ana P.; Hamblin, Michael R.

2009-02-01

Photodynamic therapy (PDT) involves the administration of photosensitizers followed by illumination of the primary tumor with red light producing reactive oxygen species that cause vascular shutdown and tumor cell necrosis and apoptosis. Anti-tumor immunity is stimulated after PDT due to the acute inflammatory response, priming of the immune system to recognize tumor-associated antigens (TAA). The induction of specific CD8+ Tlymphocyte cells that recognize major histocompatibility complex class I (MHC-I) restricted epitopes of TAAs is a highly desirable goal in cancer therapy. The PDT killed tumor cells may be phagocytosed by dendritic cells (DC) that then migrate to draining lymph nodes and prime naÃve T-cells that recognize TAA epitopes. This process is however, often sub-optimal, in part due to tumor-induced DC dysfunction. Instead of DC that can become mature and activated and have a potent antigen-presenting and immune stimulating phenotype, immature dendritic cells (iDC) are often found in tumors and are part of an immunosuppressive milieu including regulatory T-cells and immunosuppressive cytokines such as TGF-beta and IL10. We here report on the use of a potent DC activating agent, an oligonucleotide (ODN) that contains a non-methylated CpG motif and acts as an agonist of toll like receptor (TLR) 9. TLR activation is a danger signal to notify the immune system of the presence of invading pathogens. CpG-ODN (but not scrambled non-CpG ODN) increased bone-marrow DC activation after exposure to PDT-killed tumor cells, and significantly increased tumor response to PDT and mouse survival after peri-tumoral administration. CpG may be a valuable immunoadjuvant to PDT especially for tumors that produce DC dysfunction.

Endothelial cell-derived microparticles induce plasmacytoid dendritic cell maturation: potential implications in inflammatory diseases.

PubMed

Angelot, Fanny; Seillès, Estelle; Biichlé, Sabeha; Berda, Yael; Gaugler, Béatrice; Plumas, Joel; Chaperot, Laurence; Dignat-George, Françoise; Tiberghien, Pierre; Saas, Philippe; Garnache-Ottou, Francine

2009-11-01

Increased circulating endothelial microparticles, resulting from vascular endothelium dysfunction, and plasmacytoid dendritic cell activation are both encountered in common inflammatory disorders. The aim of our study was to determine whether interactions between endothelial microparticles and plasmacytoid dendritic cells could contribute to such pathologies. Microparticles generated from endothelial cell lines, platelets or activated T cells were incubated with human plasmacytoid dendritic cells sorted from healthy donor blood or with monocyte-derived dendritic cells. Dendritic cell maturation was evaluated by flow cytometry, cytokine secretion as well as naive T-cell activation and polarization. Labeled microparticles were also used to study cellular interactions. Endothelial microparticles induced plasmacytoid dendritic cell maturation. In contrast, conventional dendritic cells were resistant to endothelial microparticle-induced maturation. In addition to upregulation of co-stimulatory molecules, endothelial microparticle-matured plasmacytoid dendritic cells secreted inflammatory cytokines (interleukins 6 and 8, but no interferon-alpha) and also induced allogeneic naive CD4(+) T cells to proliferate and to produce type 1 cytokines such as interferon-gamma and tumor necrosis factor-alpha. Endothelial microparticle endocytosis by plasmacytoid dendritic cells appeared to be required for plasmacytoid dendritic cell maturation. Importantly, the ability of endothelial microparticles to induce plasmacytoid dendritic cells to mature was specific as microparticles derived from activated T cells or platelets (the major source of circulating microparticules in healthy subjects) did not induce such plasmacytoid dendritic cell maturation. Our data show that endothelial microparticles specifically induce plasmacytoid dendritic cell maturation and production of inflammatory cytokines. This novel activation pathway may be implicated in various inflammatory disorders and endothelial microparticles could be an important immunmodulatory therapeutic target.

Toxoplasma gondii Is Dependent on Glutamine and Alters Migratory Profile of Infected Host Bone Marrow Derived Immune Cells through SNAT2 and CXCR4 Pathways

PubMed Central

Lee, I-Ping; Works, Melissa G.; Kumar, Vineet; De Miguel, Zurine; Manley, Nathan C.; Sapolsky, Robert M.

2014-01-01

The obligate intracellular parasite, Toxoplasma gondii, disseminates through its host inside infected immune cells. We hypothesize that parasite nutrient requirements lead to manipulation of migratory properties of the immune cell. We demonstrate that 1) T. gondii relies on glutamine for optimal infection, replication and viability, and 2) T. gondii-infected bone marrow-derived dendritic cells (DCs) display both “hypermotility” and “enhanced migration” to an elevated glutamine gradient in vitro. We show that glutamine uptake by the sodium-dependent neutral amino acid transporter 2 (SNAT2) is required for this enhanced migration. SNAT2 transport of glutamine is also a significant factor in the induction of migration by the small cytokine stromal cell-derived factor-1 (SDF-1) in uninfected DCs. Blocking both SNAT2 and C-X-C chemokine receptor 4 (CXCR4; the unique receptor for SDF-1) blocks hypermotility and the enhanced migration in T. gondii-infected DCs. Changes in host cell protein expression following T. gondii infection may explain the altered migratory phenotype; we observed an increase of CD80 and unchanged protein level of CXCR4 in both T. gondii-infected and lipopolysaccharide (LPS)-stimulated DCs. However, unlike activated DCs, SNAT2 expression in the cytosol of infected cells was also unchanged. Thus, our results suggest an important role of glutamine transport via SNAT2 in immune cell migration and a possible interaction between SNAT2 and CXCR4, by which T. gondii manipulates host cell motility. PMID:25299045

Antitumor Responses Stimulated by Dendritic Cells Are Improved by Triiodothyronine Binding to the Thyroid Hormone Receptor β.

PubMed

Alamino, Vanina A; Mascanfroni, Iván D; Montesinos, María M; Gigena, Nicolás; Donadio, Ana C; Blidner, Ada G; Milotich, Sonia I; Cheng, Sheue-Yann; Masini-Repiso, Ana M; Rabinovich, Gabriel A; Pellizas, Claudia G

2015-04-01

Bidirectional cross-talk between the neuroendocrine and immune systems orchestrates immune responses in both physiologic and pathologic settings. In this study, we provide in vivo evidence of a critical role for the thyroid hormone triiodothyronine (T3) in controlling the maturation and antitumor functions of dendritic cells (DC). We used a thyroid hormone receptor (TR) β mutant mouse (TRβPV) to establish the relevance of the T3-TRβ system in vivo. In this model, TRβ signaling endowed DCs with the ability to stimulate antigen-specific cytotoxic T-cell responses during tumor development. T3 binding to TRβ increased DC viability and augmented DC migration to lymph nodes. Moreover, T3 stimulated the ability of DCs to cross-present antigens and to stimulate cytotoxic T-cell responses. In a B16-OVA mouse model of melanoma, vaccination with T3-stimulated DCs inhibited tumor growth and prolonged host survival, in part by promoting the generation of IFNγ-producing CD8(+) T cells. Overall, our results establish an adjuvant effect of T3-TRβ signaling in DCs, suggesting an immediately translatable method to empower DC vaccination approaches for cancer immunotherapy. ©2015 American Association for Cancer Research.

Dendritic and tumor cell fusions transduced with adenovirus encoding CD40L eradicate B-cell lymphoma and induce a Th17-type response.

PubMed

Alvarez, E; Moga, E; Barquinero, J; Sierra, J; Briones, J

2010-04-01

Fusion of dendritic cells and tumor cells (FCs) constitutes a promising tool for generating an antitumor response because of their capacity to present tumor antigens and provide appropriate costimulatory signals. CD40-CD40L interaction has an important role in the maturation and survival of dendritic cells and provides critical help for T-cell priming. In this study, we sought to improve the effectiveness of FC vaccines in a murine model of B-cell lymphoma by engineering FCs to express CD40L by means of an adenovirus encoding CD40L (Adv-CD40L). Before transduction with Adv-CD40L, no CD40L expression was detected in FCs, DCs or tumor cells. The surface expression of CD40L in FC transduced with Adv-CD40L (FC-CD40L) ranged between 50 and 60%. FC-CD40L showed an enhanced expression of CD80, CD86, CD54 and MHC class II molecules and elicited a strong in vitro immune response in a syngeneic mixed lymphocyte reaction. Furthermore, FC-CD40L showed enhanced migration to secondary lymphoid organs. Splenocytes from mice treated with FC-CD40L had a dramatic increase in the production of IL-17, IL-6 and IFN-gamma, compared with controls. Treatment with the FC-CD40L vaccine induced regression of established tumors and increased survival. Our data demonstrate that FC transduced with Adv-CD40L enhances the antitumor effect of FC vaccines in a murine lymphoma model and this is associated with an increased Th17-type immune response.

Endothelial cell-derived microparticles induce plasmacytoid dendritic cell maturation: potential implications in inflammatory diseases

PubMed Central

Angelot, Fanny; Seillès, Estelle; Biichlé, Sabeha; Berda, Yael; Gaugler, Béatrice; Plumas, Joel; Chaperot, Laurence; Dignat-George, Françoise; Tiberghien, Pierre; Saas, Philippe; Garnache-Ottou, Francine

2009-01-01

Background Increased circulating endothelial microparticles, resulting from vascular endothelium dysfunction, and plasmacytoid dendritic cell activation are both encountered in common inflammatory disorders. The aim of our study was to determine whether interactions between endothelial microparticles and plasmacytoid dendritic cells could contribute to such pathologies. Design and Methods Microparticles generated from endothelial cell lines, platelets or activated T cells were incubated with human plasmacytoid dendritic cells sorted from healthy donor blood or with monocyte-derived dendritic cells. Dendritic cell maturation was evaluated by flow cytometry, cytokine secretion as well as naive T-cell activation and polarization. Labeled microparticles were also used to study cellular interactions. Results Endothelial microparticles induced plasmacytoid dendritic cell maturation. In contrast, conventional dendritic cells were resistant to endothelial microparticle-induced maturation. In addition to upregulation of co-stimulatory molecules, endothelial microparticle-matured plasmacytoid dendritic cells secreted inflammatory cytokines (interleukins 6 and 8, but no interferon-α) and also induced allogeneic naive CD4+ T cells to proliferate and to produce type 1 cytokines such as interferon-γ and tumor necrosis factor-α. Endothelial microparticle endocytosis by plasmacytoid dendritic cells appeared to be required for plasmacytoid dendritic cell maturation. Importantly, the ability of endothelial microparticles to induce plasmacytoid dendritic cells to mature was specific as microparticles derived from activated T cells or platelets (the major source of circulating microparticules in healthy subjects) did not induce such plasmacytoid dendritic cell maturation. Conclusions Our data show that endothelial microparticles specifically induce plasmacytoid dendritic cell maturation and production of inflammatory cytokines. This novel activation pathway may be implicated in various inflammatory disorders and endothelial microparticles could be an important immunmodulatory therapeutic target. PMID:19648164

Host responses in human skin after conventional intradermal injection or microneedle administration of virus-like-particle influenza vaccine.

PubMed

Pearton, Marc; Pirri, Daniela; Kang, Sang-Moo; Compans, Richard W; Birchall, James C

2013-10-01

Miniaturized microneedle devices are being developed for painlessly targeting vaccines to the immune cell populations in skin. As skin immunization studies are generally restricted to animal models however, where skin architecture and immunity is greatly different to human, surprisingly little is known about the local human response to intradermal (ID) vaccines. Here surgically excised human skin is used to explore for the first time the complex molecular and cellular host responses to a candidate influenza vaccine comprising nanoparticulate virus-like-particles (VLPs), administered via conventional hypodermic injection or reduced scale microneedles. Responses at the molecular level are determined by microarray analysis (47,296 discrete transcripts) and validated by quantitative PCR (96 genes). Cellular response is probed through monitoring migration of dendritic cells in viable skin tissue. Gene expression mapping, ontological analysis, and qPCR reveal up-regulation of a host of genes responsible for key immunomodulatory processes and host viral response, including cell recruitment, activation, migration, and T cell interaction following both ID and microneedle injection of VLPs; the response from the microneedles being more subtle. Significant morphological and migratory changes to skin dendritic cells are also apparent following microneedle VLP delivery. This is the first study displaying the global, multifaceted immunological events that occur at the site of vaccine deposition in human skin and will subsequently influence the degree and nature of innate and adaptive immune responses. An increased understanding of the detailed similarities and differences in response against antigen administered via different delivery modalities will inform the development of improved vaccines and vaccine delivery systems. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Phenotype and function of nasal dendritic cells

PubMed Central

Lee, Haekyung; Ruane, Darren; Law, Kenneth; Ho, Yan; Garg, Aakash; Rahman, Adeeb; Esterházy, Daria; Cheong, Cheolho; Goljo, Erden; Sikora, Andrew G.; Mucida, Daniel; Chen, Benjamin; Govindraj, Satish; Breton, Gaëlle; Mehandru, Saurabh

2015-01-01

Intranasal vaccination generates immunity across local, regional and distant sites. However, nasal dendritic cells (DC), pivotal for the induction of intranasal vaccine- induced immune responses, have not been studied in detail. Here, using a variety of parameters, we define nasal DCs in mice and humans. Distinct subsets of “classical” DCs, dependent on the transcription factor zbtb46 were identified in the murine nose. The murine nasal DCs were FLT3 ligand-responsive and displayed unique phenotypic and functional characteristics including the ability to present antigen, induce an allogeneic T cell response and migrate in response to LPS or live bacterial pathogens. Importantly, in a cohort of human volunteers, BDCA-1+ DCs were observed to be the dominant nasal DC population at steady state. During chronic inflammation, the frequency of both BDCA-1+ and BDCA-3hi DCs was reduced in the nasal tissue, associating the loss of these immune sentinels with chronic nasal inflammation. The present study is the first detailed description of the phenotypic, ontogenetic and functional properties of nasal DCs and will inform the design of preventative immunization strategies as well as therapeutic modalities against chronic rhinosinusitis. PMID:25669151

Leishmania Uses Mincle to Target an Inhibitory ITAM Signaling Pathway in Dendritic Cells that Dampens Adaptive Immunity to Infection.

PubMed

Iborra, Salvador; Martínez-López, María; Cueto, Francisco J; Conde-Garrosa, Ruth; Del Fresno, Carlos; Izquierdo, Helena M; Abram, Clare L; Mori, Daiki; Campos-Martín, Yolanda; Reguera, Rosa María; Kemp, Benjamin; Yamasaki, Sho; Robinson, Matthew J; Soto, Manuel; Lowell, Clifford A; Sancho, David

2016-10-18

C-type lectin receptors sense a diversity of endogenous and exogenous ligands that may trigger differential responses. Here, we have found that human and mouse Mincle bind to a ligand released by Leishmania, a eukaryote parasite that evades an effective immune response. Mincle-deficient mice had milder dermal pathology and a tenth of the parasite burden compared to wild-type mice after Leishmania major intradermal ear infection. Mincle deficiency enhanced adaptive immunity against the parasite, correlating with increased activation, migration, and priming by Mincle-deficient dendritic cells (DCs). Leishmania triggered a Mincle-dependent inhibitory axis characterized by SHP1 coupling to the FcRγ chain. Selective loss of SHP1 in CD11c + cells phenocopies enhanced adaptive immunity to Leishmania. In conclusion, Leishmania shifts Mincle to an inhibitory ITAM (ITAMi) configuration that impairs DC activation. Thus, ITAMi can be exploited for immune evasion by a pathogen and may represent a paradigm for ITAM-coupled receptors sensing self and non-self. Copyright © 2016 Elsevier Inc. All rights reserved.

Precision Cut Mouse Lung Slices to Visualize Live Pulmonary Dendritic Cells

PubMed Central

Lyons-Cohen, Miranda R.; Thomas, Seddon Y.; Cook, Donald N.; Nakano, Hideki

2017-01-01

SHORT ABSTRACT We describe a method for generating precision-cut lung slices (PCLS) and immunostaining them to visualize the localization of various immune cell types in the lung. Our protocol can be extended to visualize the location and function of many different cell types under a variety of conditions. LONG ABSTRACT Inhalation of allergens and pathogens elicits multiple changes in a variety of immune cell types in the lung. Flow cytometry is a powerful technique for quantitative analysis of cell surface proteins on immune cells, but it provides no information on the localization and migration patterns of these cells within the lung. Similarly, in vitro chemotaxis assays can be performed to study the potential of cells to respond to chemotactic factors in vitro, but these assays do not reproduce the complex environment of the intact lung. In contrast to these aforementioned techniques, the location of individual cell types within the lung can be readily visualized by generating precision-cut lung slices (PCLS), staining them with commercially available, fluorescently tagged antibodies, and visualizing the sections by confocal microscopy. PCLS can be used for both live and fixed lung tissue, and the slices can encompass areas as large as a cross section of an entire lobe. We have used this protocol to successfully visualize the location of a wide variety of cell types in the lung, including distinct types of dendritic cells, macrophages, neutrophils, T cells and B cells, as well as structural cells such as lymphatic, endothelial, and epithelial cells. The ability to visualize cellular interactions, such as those between dendritic cells and T cells, in live, three-dimensional lung tissue, can reveal how cells move within the lung and interact with one another at steady state and during inflammation. Thus, when used in combination with other procedures, such as flow cytometry and quantitative PCR, PCLS can contribute to a comprehensive understanding of cellular events that underlie allergic and inflammatory diseases of the lung. PMID:28448013

Conventional and monocyte-derived CD11b(+) dendritic cells initiate and maintain T helper 2 cell-mediated immunity to house dust mite allergen.

PubMed

Plantinga, Maud; Guilliams, Martin; Vanheerswynghels, Manon; Deswarte, Kim; Branco-Madeira, Filipe; Toussaint, Wendy; Vanhoutte, Leen; Neyt, Katrijn; Killeen, Nigel; Malissen, Bernard; Hammad, Hamida; Lambrecht, Bart N

2013-02-21

Dendritic cells (DCs) are crucial for mounting allergic airway inflammation, but it is unclear which subset of DCs performs this task. By using CD64 and MAR-1 staining, we reliably separated CD11b(+) monocyte-derived DCs (moDCs) from conventional DCs (cDCs) and studied antigen uptake, migration, and presentation assays of lung and lymph node (LN) DCs in response to inhaled house dust mite (HDM). Mainly CD11b(+) cDCs but not CD103(+) cDCs induced T helper 2 (Th2) cell immunity in HDM-specific T cells in vitro and asthma in vivo. Studies in Flt3l(-/-) mice, lacking all cDCs, revealed that moDCs were also sufficient to induce Th2 cell-mediated immunity but only when high-dose HDM was given. The main function of moDCs was the production of proinflammatory chemokines and allergen presentation in the lung during challenge. Thus, we have identified migratory CD11b(+) cDCs as the principal subset inducing Th2 cell-mediated immunity in the LN, whereas moDCs orchestrate allergic inflammation in the lung. Copyright © 2013 Elsevier Inc. All rights reserved.

UVA radiation impairs phenotypic and functional maturation of human dermal dendritic cells.

PubMed

Furio, Laetitia; Berthier-Vergnes, Odile; Ducarre, Blandine; Schmitt, Daniel; Peguet-Navarro, Josette

2005-11-01

There is now strong evidence that the ultraviolet A (UVA) part of the solar spectrum contributes to the development of skin cancers. Its effect on the skin immune system, however, has not been fully investigated. Here, we analyzed the effects of UVA radiation on dermal dendritic cells (DDC), which, in addition, provided further characterization of these cells. Dermal sheets were obtained from normal human skin and irradiated, or not, with UVA at 2 or 12 J per cm2. After a 2 d incubation, the phenotype of emigrant cells was analyzed by double immunostaining and flow cytometry. Results showed that migratory DDC were best characterized by CD1c expression and that only few cells co-expressed the Langerhans cell marker Langerin. Whereas the DC extracted from the dermis displayed an immature phenotype, emigrant DDC showed increased expression of HLA-DR and acquired co-stimulation and maturation markers. We showed here that UVA significantly decreased the number of viable emigrant DDC, a process related to increased apoptosis. Furthermore, UVA irradiation impaired the phenotypic and functional maturation of migrating DDC into potent antigen-presenting cells, in a concentration-dependent manner. The results provide further evidence that UVA are immunosuppressive and suggest an additional mechanism by which solar radiation impairs immune response.

Tolerogenic dendritic cells in autoimmune diseases: crucial players in induction and prevention of autoimmunity.

PubMed

Torres-Aguilar, Honorio; Blank, Miri; Jara, Luis J; Shoenfeld, Yehuda

2010-11-01

The immune system has evolved to coordinate responses against numerous invading pathogens and simultaneously remain silent facing self-antigens and those derived from commensal organisms. But, if both processes are not maintained in strict balance, a potential threat can emerge due to the risk of chronic inflammation and/or autoimmunity development. Therefore, there is a negative immune regulation where tolerogenic dendritic cells (tDCs) participate actively. Under steady-state conditions, tDC are notably involved in the elimination of autoreactive T cells at the thymus, and in the control of T cells specific to self and harmless antigens in the periphery. But in the presence of foreign antigens in an inflammatory milieu, dendritic cells (DCs) mature and induce T cells activation and their migration to B cell areas to assist in antibody production. Additionally, there are other factors such as infections, anti tumoral immune responses, trauma-mediated disruption, etc. that may induce alterations in the balance between tolerogenic and immunogenic functions of DCs and instigate the development of autoimmune diseases (ADs). Therefore, in recent years, DCs have emerged as therapeutic targets to control of ADs. Diverse strategies in vitro and/or in animal models of ADs have explored the tolerogenic functions of DCs and demonstrated their feasibility to prevent or control an autoimmune process, but still leaving a void in their application in clinical assays. The purpose of this paper is to give a general overview of the current literature on the significance of tDCs in tolerance maintenance to self and innocuous antigens, the most relevant alterations involved in the pathophysiology of ADs, the cellular and molecular mechanisms involved in their tolerogenic function and the current strategies used to exploit their tolerogenic potential. Published by Elsevier B.V.

Expression of Chicken DEC205 Reflects the Unique Structure and Function of the Avian Immune System

PubMed Central

Staines, Karen; Young, John R.; Butter, Colin

2013-01-01

The generation of appropriate adaptive immune responses relies critically on dendritic cells, about which relatively little is known in chickens, a vital livestock species, in comparison with man and mouse. We cloned and sequenced chicken DEC205 cDNA and used this knowledge to produce quantitative PCR assays and monoclonal antibodies to study expression of DEC205 as well as CD83. The gene structure of DEC205 was identical to those of other species. Transcripts of both genes were found at higher levels in lymphoid tissues and the expression of DEC205 in normal birds had a characteristic distribution in the primary lymphoid organs. In spleen, DEC205 was seen on cells ideally located to trap antigen. In thymus it was found on cells thought to participate in the education of T cells, and in the bursa on cells that may be involved in presentation of antigen to B cells and regulation of B cell migration. The expression of DEC205 on cells other than antigen presenting cells (APC) is also described. Isolated splenocytes strongly expressing DEC205 but not the KUL01 antigen have morphology similar to mammalian dendritic cells and the distinct expression of DEC205 within the avian-specific Bursa of Fabricius alludes to a unique function in this organ of B cell diversification. PMID:23326318

The Good, the Bad, and the Ugly of Dendritic Cells during Prion Disease

PubMed Central

Mabbott, Neil Andrew; Bradford, Barry Matthew

2015-01-01

Prions are a unique group of proteinaceous pathogens which cause neurodegenerative disease and can be transmitted by a variety of exposure routes. After peripheral exposure, the accumulation and replication of prions within secondary lymphoid organs are obligatory for their efficient spread from the periphery to the brain where they ultimately cause neurodegeneration and death. Mononuclear phagocytes (MNP) are a heterogeneous population of dendritic cells (DC) and macrophages. These cells are abundant throughout the body and display a diverse range of roles based on their anatomical locations. For example, some MNP are strategically situated to provide a first line of defence against pathogens by phagocytosing and destroying them. Conventional DC are potent antigen presenting cells and migrate via the lymphatics to the draining lymphoid tissue where they present the antigens to lymphocytes. The diverse roles of MNP are also reflected in various ways in which they interact with prions and in doing so impact on disease pathogenesis. Indeed, some studies suggest that prions exploit conventional DC to infect the host. Here we review our current understanding of the influence of MNP in the pathogenesis of the acquired prion diseases with particular emphasis on the role of conventional DC. PMID:26697507

Load Adaptation of Lamellipodial Actin Networks.

PubMed

Mueller, Jan; Szep, Gregory; Nemethova, Maria; de Vries, Ingrid; Lieber, Arnon D; Winkler, Christoph; Kruse, Karsten; Small, J Victor; Schmeiser, Christian; Keren, Kinneret; Hauschild, Robert; Sixt, Michael

2017-09-21

Actin filaments polymerizing against membranes power endocytosis, vesicular traffic, and cell motility. In vitro reconstitution studies suggest that the structure and the dynamics of actin networks respond to mechanical forces. We demonstrate that lamellipodial actin of migrating cells responds to mechanical load when membrane tension is modulated. In a steady state, migrating cell filaments assume the canonical dendritic geometry, defined by Arp2/3-generated 70° branch points. Increased tension triggers a dense network with a broadened range of angles, whereas decreased tension causes a shift to a sparse configuration dominated by filaments growing perpendicularly to the plasma membrane. We show that these responses emerge from the geometry of branched actin: when load per filament decreases, elongation speed increases and perpendicular filaments gradually outcompete others because they polymerize the shortest distance to the membrane, where they are protected from capping. This network-intrinsic geometrical adaptation mechanism tunes protrusive force in response to mechanical load. Copyright © 2017 Elsevier Inc. All rights reserved.

Neuropilin 2 Signaling Is Involved in Cell Positioning of Adult-born Neurons through Glycogen Synthase Kinase-3β (GSK3β).

PubMed

Ng, Teclise; Hor, Catherine H H; Chew, Benjamin; Zhao, Jing; Zhong, Zhong; Ryu, Jae Ryun; Goh, Eyleen L K

2016-11-25

Proper positioning of neurons is fundamental for brain functions. However, little is known on how adult-born neurons generated in the hilar side of hippocampal dentate gyrus migrate into the granular cell layer. Because class 3 Semaphorins (Sema3) are involved in dendritic growth of these newborn neurons, we examined whether they are essential for cell positioning. We disrupted Sema3 signaling by silencing neuropilin 1 (NRP1) or 2 (NRP2), the main receptors for Sema3A and Sema3F, in neural progenitors of adult mouse dentate gyrus. Silencing of NRP2, but not NRP1, affected cell positioning of adult newborn neurons. Glycogen synthase kinase-3β (GSK3β) knockdown phenocopied this NRP2 silencing-mediated cell positioning defect, but did not affect dendritic growth. Furthermore, GSK3β is activated upon stimulation with Sema3F, and GSK3β overexpression rescued the cell positioning phenotypes seen in NRP2-deficient neurons. These results point to a new role for NRP2 in the positioning of neurons during adult hippocampal neurogenesis, acting via the GSK3β signaling pathway. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Microbiota regulate the ability of lung dendritic cells to induce IgA class-switch recombination and generate protective gastrointestinal immune responses

PubMed Central

Ruane, Darren; Chorny, Alejo; Lee, Haekyung; Faith, Jeremiah; Pandey, Gaurav; Shan, Meimei; Simchoni, Noa; Rahman, Adeeb; Garg, Aakash; Weinstein, Erica G.; Oropallo, Michael; Gaylord, Michelle; Ungaro, Ryan; Cunningham-Rundles, Charlotte; Alexandropoulos, Konstantina; Mucida, Daniel; Merad, Miriam; Cerutti, Andrea

2016-01-01

Protective immunoglobulin A (IgA) responses to oral antigens are usually orchestrated by gut dendritic cells (DCs). Here, we show that lung CD103+ and CD24+CD11b+ DCs induced IgA class-switch recombination (CSR) by activating B cells through T cell–dependent or –independent pathways. Compared with lung DCs (LDC), lung CD64+ macrophages had decreased expression of B cell activation genes and induced significantly less IgA production. Microbial stimuli, acting through Toll-like receptors, induced transforming growth factor-β (TGF-β) production by LDCs and exerted a profound influence on LDC-mediated IgA CSR. After intranasal immunization with inactive cholera toxin (CT), LDCs stimulated retinoic acid–dependent up-regulation of α4β7 and CCR9 gut-homing receptors on local IgA-expressing B cells. Migration of these B cells to the gut resulted in IgA-mediated protection against an oral challenge with active CT. However, in germ-free mice, the levels of LDC-induced, CT–specific IgA in the gut are significantly reduced. Herein, we demonstrate an unexpected role of the microbiota in modulating the protective efficacy of intranasal vaccination through their effect on the IgA class-switching function of LDCs. PMID:26712806

Investigations of the functional states of dendritic cells under different conditioned microenvironments by Fourier transformed infrared spectroscopy.

PubMed

Dong, Rong; Long, Jinhua; Xu, Xiaoli; Zhang, Chunlin; Wen, Zongyao; Li, Long; Yao, Weijuan; Zeng, Zhu

2014-01-10

Dendritic cells are potent and specialized antigen presenting cells, which play a crucial role in initiating and amplifying both the innate and adaptive immune responses. The dendritic cell-based vaccination against cancer has been clinically achieved promising successes. But there are still many challenges in its clinical application, especially for how to identify the functional states. The CD14+ monocytes were isolated from human peripheral blood after plastic adherence and purified to approximately 98% with cocktail immunomagnetic beads. The immature dendritic cells and mature dendritic cells were induced by traditional protocols. The resulting dendritic cells were cocultured with normal cells and cancer cells. The functional state of dendritic cells including immature dendritic cells (imDCs) and mature dendritic cells (mDCs) under different conditioned microenvironments were investigated by Fourier transformed infrared spectroscopy (FTIR) and molecular biological methods. The results of Fourier transformed infrared spectroscopy showed that the gene transcription activity and energy states of dendritic cells were specifically suppressed by tumor cells (P < 0.05 or 0.01). The expression levels of NF-kappa B (NF-κB) in dendritic cells were also specifically inhibited by tumor-derived factors (P < 0.05 or 0.01). Moreover, the ratios of absorption intensities of Fourier transformed infrared spectroscopy at given wave numbers were closely correlated with the expression levels of NF-κB (R2:0.69 and R2:0.81, respectively). Our results confirmed that the ratios of absorption intensities of Fourier transformed infrared spectroscopy at given wave numbers were positively correlated with the expression levels of NF-κB, suggesting that Fourier transformed infrared spectroscopy technology could be clinically applied to identify the functional states of dendritic cell when performing dendritic cell-based vaccination. It's significant for the simplification and standardization of dendritic cell-based vaccination clinical preparation protocols.

Immunosuppressant effect of IDS 30, a stinging nettle leaf extract, on myeloid dendritic cells in vitro.

PubMed

Broer, Johanna; Behnke, Bert

2002-04-01

Dendritic cells are important antigen presenting cells that play a role in the initiation of rheumatoid arthritis (RA). The stinging nettle leaf extract IDS 30 (Hox alpha) has been recommended for adjuvant therapy of rheumatic diseases. We investigated the immunomodulating effect of IDS 30 extract on the maturation of hematopoietic dendritic cells. Human dendritic cells were generated from peripheral blood mononuclear cells cultured in granulocyte macrophage-colony stimulating factor and interleukin 4 (IL-4). Dendritic cell maturation was induced by keyhole limped hemocyanin (KLH). Dendritic cell phenotype was characterized by flow cytometric analysis; dendritic cell cytokine production was measured by ELISA. The ability of dendritic cells to activate naive autologous T cells was evaluated by mixed leukocyte reaction. IDS 30 prevented the maturation of dendritic cells, but did not affect their viability. IDS 30 reduced the expression of CD83 and CD86. It increased the expression of chemokine receptor 5 and CD36 in a dose dependent manner. The secretion of tumor necrosis factor-alpha was reduced. Application of IDS 30 to dendritic cells in culture caused a high endocytosis of dextran and a low capacity to stimulate T cell proliferation. Our in vitro results showed the suppressive effect of IDS 30 on the maturation of human myeloid dendritic cells, leading to reduced induction of primary T cell responses. This may contribute to the therapeutic effect of IDS 30 on T cell mediated inflammatory diseases like RA.

Self-heating–induced healing of lithium dendrites

NASA Astrophysics Data System (ADS)

Li, Lu; Basu, Swastik; Wang, Yiping; Chen, Zhizhong; Hundekar, Prateek; Wang, Baiwei; Shi, Jian; Shi, Yunfeng; Narayanan, Shankar; Koratkar, Nikhil

2018-03-01

Lithium (Li) metal electrodes are not deployable in rechargeable batteries because electrochemical plating and stripping invariably leads to growth of dendrites that reduce coulombic efficiency and eventually short the battery. It is generally accepted that the dendrite problem is exacerbated at high current densities. Here, we report a regime for dendrite evolution in which the reverse is true. In our experiments, we found that when the plating and stripping current density is raised above ~9 milliamperes per square centimeter, there is substantial self-heating of the dendrites, which triggers extensive surface migration of Li. This surface diffusion heals the dendrites and smoothens the Li metal surface. We show that repeated doses of high-current-density healing treatment enables the safe cycling of Li-sulfur batteries with high coulombic efficiency.

CpG Oligodeoxynucleotides Facilitate Delivery of Whole Inactivated H9N2 Influenza Virus via Transepithelial Dendrites of Dendritic Cells in Nasal Mucosa

PubMed Central

Qin, Tao; Yin, Yinyan; Yu, Qinghua; Huang, Lulu; Wang, Xiaoqing; Lin, Jian

2015-01-01

ABSTRACT The spread of the low-pathogenicity avian H9N2 influenza virus has seriously increased the risk of a new influenza pandemic. Although whole inactivated virus (WIV) vaccine via intranasal pathway is the effective method of blocking virus transmission, the mucosal barrier seems to be a major factor hampering its development. CpG oligodeoxynucleotides, a known adjuvant, can target downstream dendritic cells (DCs) and effectively enhance the mucosal and systemic immune responses. However, the ability of CpGs to assist H9N2 WIV in transepithelial transport remains unknown. Here, in vitro and in vivo, we showed that CpGs provided assistance for H9N2 WIV in recruiting DCs to the nasal epithelial cells (ECs) and forming transepithelial dendrites (TEDs) to capture luminal viruses. CD103+ DCs participated in this process. Chemokine CCL20 from nasal ECs played a key role in driving DC recruitment and TED formation. Virus-loaded DCs quickly migrated into the draining cervical lymph nodes (CLNs) for antigen presentation. In addition, the competence of CpGs was independent of direct epithelial transport via the transcellular or paracellular pathway. Taken together, our data demonstrated that CpGs enhanced the transport of H9N2 WIV via TEDs of nasal DCs, which might be a novel mechanism for optimal adaptive immune responses. IMPORTANCE This paper demonstrates by both an in vivo and an in vitro coculture model that CpG oligodeoxynucleotides, known as an adjuvant generally targeting downstream immune responses, also are crucial for the transport of H9N2 WIV across nasal epithelial cells (ECs) via the uptake of transepithelial dendrites (TEDs). Our results prove for the first time to our knowledge that the immune-potentiating mechanism of CpGs is based on strengthening the transepithelial uptake of H9N2 WIV in nasal mucosa. These findings provide a fresh perspective for further improvement of intranasal influenza vaccines, which are urgently needed in the face of the potential threat of H9N2 influenza. PMID:25810544

Divergent Effects of Dendritic Cells on Pancreatitis

DTIC Science & Technology

2015-09-01

role of dendritic cells in pancreatitis. Dendritic cells are professional antigen presenting cells which initiate innate and adaptive immune... Lymphoid -tissue-specific homing of bone- marrow-derived dendritic cells . Blood. 113:6638–6647. http://dx.doi .org/10.1182/blood-2009-02-204321 Dapito...Award Number: W81XWH-12-1-0313 TITLE: Divergent Effects of Dendritic Cells on Pancreatitis PRINCIPAL INVESTIGATOR: Dr. George Miller

Early stages in the development of human T, natural killer and thymic dendritic cells.

PubMed

Spits, H; Blom, B; Jaleco, A C; Weijer, K; Verschuren, M C; van Dongen, J J; Heemskerk, M H; Res, P C

1998-10-01

T-cell development is initiated when CD34+ pluripotent stem cells or their immediate progeny leave the bone marrow to migrate to the thymus. Upon arrival in the thymus the stem cell progeny is not yet committed to the T-cell lineage as it has the capability to develop into T, natural killer (NK) and dendritic cells (DC). Primitive hematopoietic progenitor cells in the human thymus express CD34 and lack CD1a. When these progenitor cells develop into T cells they traverse a number of checkpoints. One early checkpoint is the induction of T-cell commitment, which correlates with appearance of CD1a and involves the loss of capacity to develop into NK cells and DC and the initiation of T-cell receptor (TCR) gene rearrangements. Basic helix-loop-helix transcription factors play a role in induction of T-cell commitment. CD1a+CD34+ cells develop into CD4+CD8 alpha+ beta+ cells by upregulating first CD4, followed by CD8 alpha and then CD8 beta. Selection for productive TCR beta gene rearrangements (beta selection) likely occurs in the CD4+CD8 alpha+ beta- and CD4+CD8 alpha+ beta+ populations. Although the T and NK-cell lineages are closely related to each other, NK cells can develop independently of the thymus. The fetal thymus is most likely one site of NK-cell development.

Septic shock sera containing circulating histones induce dendritic cell-regulated necrosis in fatal septic shock patients.

PubMed

Raffray, Loic; Douchet, Isabelle; Augusto, Jean-Francois; Youssef, Jihad; Contin-Bordes, Cecile; Richez, Christophe; Duffau, Pierre; Truchetet, Marie-Elise; Moreau, Jean-Francois; Cazanave, Charles; Leroux, Lionel; Mourrissoux, Gaelle; Camou, Fabrice; Clouzeau, Benjamin; Jeannin, Pascale; Delneste, Yves; Gabinski, Claude; Guisset, Olivier; Lazaro, Estibaliz; Blanco, Patrick

2015-04-01

Innate immune system alterations, including dendritic cell loss, have been reproducibly observed in patients with septic shock and correlated to adverse outcomes or nosocomial infections. The goal of this study is to better understand the mechanisms behind this observation in order to better assess septic shock pathogenesis. Prospective, controlled experimental study. Research laboratory at an academic medical center. The study enrolled 71 patients, 49 with septic shock and 22 with cardiogenic shock. Seventeen healthy controls served as reference. In vitro monocyte-derived dendritic cells were generated from healthy volunteers. Sera were assessed for their ability to promote in vitro dendritic cell death through flow cytometry detection in each group of patients. The percentage of apoptotic or necrotic dendritic cells was evaluated by annexin-V and propidium iodide staining. We observed that only patients with septic shock and not patients with pure cardiogenic shock were characterized by a rapid and profound loss of circulating dendritic cells. In vitro analysis revealed that sera from patients with septic shock induced higher dendritic cell death compared to normal sera or cardiogenic shock (p<0.005). Sera from surviving patients induced dendritic cell death through a caspase-dependent apoptotic pathway, whereas sera from nonsurviving patients induced dendritic cell-regulated necrosis. Dendritic cell necrosis was not due to necroptosis but was dependent of the presence of circulating histone. The toxicity of histones toward dendritic cell could be prevented by recombinant human activated protein C. Finally, we observed a direct correlation between the levels of circulating histones in patients and the ability of the sera to promote dendritic cell-regulated necrosis. The study demonstrates a differential mechanism of dendritic cell death in patients with septic shock that is dependent on the severity of the disease.

The Gene Expression Profile of CD11c+CD8α− Dendritic Cells in the Pre-Diabetic Pancreas of the NOD Mouse

PubMed Central

Beumer, Wouter; Welzen-Coppens, Jojanneke M. C.; van Helden-Meeuwsen, Cornelia G.; Gibney, Sinead M.; Drexhage, Hemmo A.; Versnel, Marjan A.

2014-01-01

Two major dendritic cell (DC) subsets have been described in the pancreas of mice: The CD11c+CD8α− DCs (strong CD4+ T cell proliferation inducers) and the CD8α+CD103+ DCs (T cell apoptosis inducers). Here we analyzed the larger subset of CD11c+CD8α− DCs isolated from the pancreas of pre-diabetic NOD mice for genome-wide gene expression (validated by Q-PCR) to elucidate abnormalities in underlying gene expression networks. CD11c+CD8α− DCs were isolated from 5 week old NOD and control C57BL/6 pancreas. The steady state pancreatic NOD CD11c+CD8α− DCs showed a reduced expression of several gene networks important for the prime functions of these cells, i.e. for cell renewal, immune tolerance induction, migration and for the provision of growth factors including those for beta cell regeneration. A functional in vivo BrdU incorporation test showed the reduced proliferation of steady state pancreatic DC. The reduced expression of tolerance induction genes (CD200R, CCR5 and CD24) was supported on the protein level by flow cytometry. Also previously published functional tests on maturation, immune stimulation and migration confirm the molecular deficits of NOD steady state DC. Despite these deficiencies NOD pancreas CD11c+CD8α− DCs showed a hyperreactivity to LPS, which resulted in an enhanced pro-inflammatory state characterized by a gene profile of an enhanced expression of a number of classical inflammatory cytokines. The enhanced up-regulation of inflammatory genes was supported by the in vitro cytokine production profile of the DCs. In conclusion, our data show that NOD pancreatic CD11c+CD8α− DCs show various deficiencies in steady state, while hyperreactive when encountering a danger signal such as LPS. PMID:25166904

In vivo and in vitro sensitivity of blastic plasmacytoid dendritic cell neoplasm to SL-401, an interleukin-3 receptor targeted biologic agent.

PubMed

Angelot-Delettre, Fanny; Roggy, Anne; Frankel, Arthur E; Lamarthee, Baptiste; Seilles, Estelle; Biichle, Sabeha; Royer, Bernard; Deconinck, Eric; Rowinsky, Eric K; Brooks, Christopher; Bardet, Valerie; Benet, Blandine; Bennani, Hind; Benseddik, Zehaira; Debliquis, Agathe; Lusina, Daniel; Roussel, Mikael; Solly, Françoise; Ticchioni, Michel; Saas, Philippe; Garnache-Ottou, Francine

2015-02-01

Blastic plasmacytoid dendritic cell neoplasm is an aggressive malignancy derived from plasmacytoid dendritic cells. There is currently no accepted standard of care for treating this neoplasm, and therapeutic strategies have never been prospectively evaluated. Since blastic plasmacytoid dendritic cell neoplasm cells express high levels of interleukin-3 receptor α chain (IL3-Rα or CD123), antitumor effects of the interleukin-3 receptor-targeted drug SL-401 against blastic plasmacytoid dendritic cell neoplasm were evaluated in vitro and in vivo. The cytotoxicity of SL-401 was assessed in patient-derived blastic plasmacytoid dendritic cell neoplasm cell lines (CAL-1 and GEN2.2) and in primary blastic plasmacytoid dendritic cell neoplasm cells isolated from 12 patients using flow cytometry and an in vitro cytotoxicity assay. The cytotoxic effects of SL-401 were compared to those of several relevant cytotoxic agents. SL-401 exhibited a robust cytotoxicity against blastic plasmacytoid dendritic cell neoplasm cells in a dose-dependent manner. Additionally, the cytotoxic effects of SL-401 were observed at substantially lower concentrations than those achieved in clinical trials to date. Survival of mice inoculated with a blastic plasmacytoid dendritic cell neoplasm cell line and treated with a single cycle of SL-401 was significantly longer than that of untreated controls (median survival, 58 versus 17 days, P<0.001). These findings indicate that blastic plasmacytoid dendritic cell neoplasm cells are highly sensitive to SL-401, and support further evaluation of SL-401 in patients suffering from blastic plasmacytoid dendritic cell neoplasm. Copyright© Ferrata Storti Foundation.

In vivo and in vitro sensitivity of blastic plasmacytoid dendritic cell neoplasm to SL-401, an interleukin-3 receptor targeted biologic agent

PubMed Central

Angelot-Delettre, Fanny; Roggy, Anne; Frankel, Arthur E.; Lamarthee, Baptiste; Seilles, Estelle; Biichle, Sabeha; Royer, Bernard; Deconinck, Eric; Rowinsky, Eric K.; Brooks, Christopher; Bardet, Valerie; Benet, Blandine; Bennani, Hind; Benseddik, Zehaira; Debliquis, Agathe; Lusina, Daniel; Roussel, Mikael; Solly, Françoise; Ticchioni, Michel; Saas, Philippe; Garnache-Ottou, Francine

2015-01-01

Blastic plasmacytoid dendritic cell neoplasm is an aggressive malignancy derived from plasmacytoid dendritic cells. There is currently no accepted standard of care for treating this neoplasm, and therapeutic strategies have never been prospectively evaluated. Since blastic plasmacytoid dendritic cell neoplasm cells express high levels of interleukin-3 receptor α chain (IL3-Rα or CD123), antitumor effects of the interleukin-3 receptor-targeted drug SL-401 against blastic plasmacytoid dendritic cell neoplasm were evaluated in vitro and in vivo. The cytotoxicity of SL-401 was assessed in patient-derived blastic plasmacytoid dendritic cell neoplasm cell lines (CAL-1 and GEN2.2) and in primary blastic plasmacytoid dendritic cell neoplasm cells isolated from 12 patients using flow cytometry and an in vitro cytotoxicity assay. The cytotoxic effects of SL-401 were compared to those of several relevant cytotoxic agents. SL-401 exhibited a robust cytotoxicity against blastic plasmacytoid dendritic cell neoplasm cells in a dose-dependent manner. Additionally, the cytotoxic effects of SL-401 were observed at substantially lower concentrations than those achieved in clinical trials to date. Survival of mice inoculated with a blastic plasmacytoid dendritic cell neoplasm cell line and treated with a single cycle of SL-401 was significantly longer than that of untreated controls (median survival, 58 versus 17 days, P<0.001). These findings indicate that blastic plasmacytoid dendritic cell neoplasm cells are highly sensitive to SL-401, and support further evaluation of SL-401 in patients suffering from blastic plasmacytoid dendritic cell neoplasm. PMID:25381130

Chemerin regulation and role in host defense.

PubMed

Zabel, Brian A; Kwitniewski, Mateusz; Banas, Magdalena; Zabieglo, Katarzyna; Murzyn, Krzysztof; Cichy, Joanna

2014-01-01

Chemerin is a widely distributed multifunctional secreted protein implicated in immune cell migration, adipogenesis, osteoblastogenesis, angiogenesis, myogenesis, and glucose homeostasis. Chemerin message is regulated by nuclear receptor agonists, metabolic signaling proteins and intermediates, and proinflammatory cytokines. Following translation chemerin is secreted as an inactive pro-protein, and its secretion can be regulated depending on cell type. Chemerin bioactivity is largely dependent on carboxyl-terminal proteolytic processing and removal of inhibitory residues. Chemerin is abundant in human epidermis where it is well-placed to provide barrier protection. In host defense, chemerin plays dual roles as a broad spectrum antimicrobial protein and as a leukocyte attractant for macrophages, dendritic cells, and NK cells. Here we review the mechanisms underlying chemerin regulation and its function in host defense.

Langerhans cells beta 2-adrenoceptors: role in migration, cytokine production, Th priming and contact hypersensitivity.

PubMed

Maestroni, Georges J M; Mazzola, Paola

2003-11-01

We showed that norepinephrine (NE) hampers IL-12 and stimulates IL-10 production via adrenoceptors (ARs) in bone marrow-derived dendritic cells (BMDC) influencing their Th priming ability. Others have shown that Langerhans cells (LC) express mRNA for beta1-, beta2- and alpha1(A)-(ARs) and that catecholamines may inhibit the antigen-presenting capability via beta2-ARs. Here, we show that also BMDC express mRNA for beta1-, beta2-, alpha2(A)- and alpha2(C)-ARs. Inhibition of IL-12 is mediated by both beta2- and alpha2(A)-ARs, while stimulation of IL-10 by beta2-ARs only. In addition, LC migration, the contact hypersensitivity response (CHS) and production of IFN-gamma and IL-2 in draining lymph node cells is increased in mice treated topically with the beta2-AR antagonist ICI 118,551 during FITC sensitization. Activation of beta2-ARs in BMDC before adoptive transfer could reduce both migration and CHS response to FITC. Finally, preincubation of BMDC with LPS in presence of the specific beta2-AR agonist salbutamol impaired their chemotactic response to CCL19 and CCL21 and this effect was neutralized by anti-IL-10 mAb. We suggest that the physiological activation of beta2-ARs in DC (LC) results in stimulation of IL-10 which in turn restrains DC (LC) migration influencing antigen presentation and the consequent CHS response.

Dendritic Kv3.3 potassium channels in cerebellar purkinje cells regulate generation and spatial dynamics of dendritic Ca2+ spikes.

PubMed

Zagha, Edward; Manita, Satoshi; Ross, William N; Rudy, Bernardo

2010-06-01

Purkinje cell dendrites are excitable structures with intrinsic and synaptic conductances contributing to the generation and propagation of electrical activity. Voltage-gated potassium channel subunit Kv3.3 is expressed in the distal dendrites of Purkinje cells. However, the functional relevance of this dendritic distribution is not understood. Moreover, mutations in Kv3.3 cause movement disorders in mice and cerebellar atrophy and ataxia in humans, emphasizing the importance of understanding the role of these channels. In this study, we explore functional implications of this dendritic channel expression and compare Purkinje cell dendritic excitability in wild-type and Kv3.3 knockout mice. We demonstrate enhanced excitability of Purkinje cell dendrites in Kv3.3 knockout mice, despite normal resting membrane properties. Combined data from local application pharmacology, voltage clamp analysis of ionic currents, and assessment of dendritic Ca(2+) spike threshold in Purkinje cells suggest a role for Kv3.3 channels in opposing Ca(2+) spike initiation. To study the physiological relevance of altered dendritic excitability, we measured [Ca(2+)](i) changes throughout the dendritic tree in response to climbing fiber activation. Ca(2+) signals were specifically enhanced in distal dendrites of Kv3.3 knockout Purkinje cells, suggesting a role for dendritic Kv3.3 channels in regulating propagation of electrical activity and Ca(2+) influx in distal dendrites. These findings characterize unique roles of Kv3.3 channels in dendrites, with implications for synaptic integration, plasticity, and human disease.

Lis1 controls dynamics of neuronal filopodia and spines to impact synaptogenesis and social behaviour

PubMed Central

Sudarov, Anamaria; Gooden, Frank; Tseng, Debbie; Gan, Wen-Biao; Ross, Margaret Elizabeth

2013-01-01

LIS1 (PAFAH1B1) mutation can impair neuronal migration, causing lissencephaly in humans. LIS1 loss is associated with dynein protein motor dysfunction, and disrupts the actin cytoskeleton through disregulated RhoGTPases. Recently, LIS1 was implicated as an important protein-network interaction node with high-risk autism spectrum disorder genes expressed in the synapse. How LIS1 might participate in this disorder has not been investigated. We examined the role of LIS1 in synaptogenesis of post-migrational neurons and social behaviour in mice. Two-photon imaging of actin-rich dendritic filopodia and spines in vivo showed significant reductions in elimination and turnover rates of dendritic protrusions of layer V pyramidal neurons in adolescent Lis1+/− mice. Lis1+/− filopodia on immature hippocampal neurons in vitro exhibited reduced density, length and RhoA dependent impaired dynamics compared to Lis1+/+. Moreover, Lis1+/− adolescent mice exhibited deficits in social interaction. Lis1 inactivation restricted to the postnatal hippocampus resulted in similar deficits in dendritic protrusion density and social interactions. Thus, LIS1 plays prominently in dendritic filopodia dynamics and spine turnover implicating reduced dendritic spine plasticity as contributing to developmental autistic-like behaviour. PMID:23483716

Rab7b at the intersection of intracellular trafficking and cell migration.

PubMed

Distefano, Marita Borg; Kjos, Ingrid; Bakke, Oddmund; Progida, Cinzia

2015-01-01

Rab proteins are small GTPases essential for controlling and coordinating intracellular traffic. The small GTPase Rab7b regulates the retrograde transport from late endosomes toward the Trans-Golgi Network (TGN), and is important for the proper trafficking of several receptors such as Toll-like receptors (TLRs) and sorting receptors. We recently identified the actin motor protein myosin II as a new interaction partner for Rab7b, and found that Rab7b transport is dependent on myosin II. Interestingly, we also discovered that Rab7b influences the phosphorylation state of myosin II by controlling the activation status of the small GTPase RhoA. Consequently, Rab7b is important for the remodeling of actin filaments in processes such as stress fiber formation, cell adhesion, polarization and cell migration. Our finding that Rab7b can control actomyosin reorganization reveals yet another important role for Rab proteins, in addition to their already established role as master regulators of intracellular transport. Here we discuss our findings and speculate how they can explain the importance of Rab7b in dendritic cells (DCs).

Rapid Pathogen-Induced Apoptosis: A Mechanism Used by Dendritic Cells to Limit Intracellular Replication of Legionella pneumophila

PubMed Central

Nogueira, Catarina V.; Lindsten, Tullia; Jamieson, Amanda M.; Case, Christopher L.; Shin, Sunny; Thompson, Craig B.; Roy, Craig R.

2009-01-01

Dendritic cells (DCs) are specialized phagocytes that internalize exogenous antigens and microbes at peripheral sites, and then migrate to lymphatic organs to display foreign peptides to naïve T cells. There are several examples where DCs have been shown to be more efficient at restricting the intracellular replication of pathogens compared to macrophages, a property that could prevent DCs from enhancing pathogen dissemination. To understand DC responses to pathogens, we investigated the mechanisms by which mouse DCs are able to restrict replication of the intracellular pathogen Legionella pneumophila. We show that both DCs and macrophages have the ability to interfere with L. pneumophila replication through a cell death pathway mediated by caspase-1 and Naip5. L. pneumophila that avoided Naip5-dependent responses, however, showed robust replication in macrophages but remained unable to replicate in DCs. Apoptotic cell death mediated by caspase-3 was found to occur much earlier in DCs following infection by L. pneumophila compared to macrophages infected similarly. Eliminating the pro-apoptotic proteins Bax and Bak or overproducing the anti-apoptotic protein Bcl-2 were both found to restore L. pneumophila replication in DCs. Thus, DCs have a microbial response pathway that rapidly activates apoptosis to limit pathogen replication. PMID:19521510

Blue Nevi and Related Tumors.

PubMed

Zembowicz, Artur

2017-09-01

The major entities related to blue nevus are common blue nevus, cellular blue nevus, atypical blue nevus, and malignant blue nevus. These lesions share presence of dermal pigmented dendritic melanocytes derived from embryonal precursors to melanocytes, Schwann cells, and glial cells migrating to the skin from the ventral neural crest. Genetically, blue nevi harbor mutations in G-protein-coupled receptor subunits GNAQ and GNA11. Progression to malignant blue nevus is associated with additional mutations and partial gains and losses of chromosomal material. This article discusses recent advances in pathology of blue nevi with emphasis on differential diagnosis and molecular pathology. Copyright © 2017 Elsevier Inc. All rights reserved.

Role of mTOR Complexes in Neurogenesis.

PubMed

LiCausi, Francesca; Hartman, Nathaniel W

2018-05-22

Dysregulation of neural stem cells (NSCs) is associated with several neurodevelopmental disorders, including epilepsy and autism spectrum disorder. The mammalian target of rapamycin (mTOR) integrates the intracellular signals to control cell growth, nutrient metabolism, and protein translation. mTOR regulates many functions in the development of the brain, such as proliferation, differentiation, migration, and dendrite formation. In addition, mTOR is important in synaptic formation and plasticity. Abnormalities in mTOR activity is linked with severe deficits in nervous system development, including tumors, autism, and seizures. Dissecting the wide-ranging roles of mTOR activity during critical periods in development will greatly expand our understanding of neurogenesis.

Clinicopathologic features and pathogenesis of melanocytic colonization in atypical meningioma.

PubMed

Dehghan Harati, Mitra; Yu, Andrew; Magaki, Shino D; Perez-Rosendahl, Mari; Im, Kyuseok; Park, Young K; Bergsneider, Marvin; Yong, William H

2018-02-01

Only two prior cases of benign dendritic melanocytes colonizing a meningioma have been reported. We add a third case, describe clinicopathologic features shared by the three, and elucidate the risk factors for this very rare phenomenon. A 29 year-old Hispanic woman presented with headache and hydrocephalus. MRI showed a lobulated enhancing pineal region mass measuring 41 mm in greatest dimension. Subtotal resection of the mass demonstrated an atypical meningioma, WHO grade II, and the patient subsequently underwent radiotherapy. She presented 4 years later with diplopia, and MRI showed an enhancing extra-axial mass measuring 47 mm in greatest dimension and centered on the tentorial incisura. Subtotal resection showed a brain-invasive atypical meningioma with melanocytic colonization. The previous two cases in the literature were atypical meningiomas, one of which was also brain invasive. Atypical meningiomas may be at particular risk for melanocytic colonization as they upregulate molecules known to be chemoattractants for melanocytes. We detected c-Kit expression in a minority of the melanocytes as well as stem cell factor and basic fibroblast growth factor in the meningioma cells, suggesting that mechanisms implicated in normal melanocyte migration may be involved. In some cases, brain invasion with disruption of the leptomeningeal barrier may also facilitate migration from the subarachnoid space into the tumor. Whether there is low-level proliferation of the dendritic melanocytes is unclear. Given that all three patients were non-Caucasian, meningiomas in persons and/or brain regions with increased dendritic melanocytes may predispose to colonization. The age range spanned from 6 years old to 70 years old. All three patients were female. The role of gender and estrogen in the pathogenesis of this entity remains to be clarified. Whether melanocytic colonization may also occur in the more common Grade I meningiomas awaits identification of additional cases. © 2017 Japanese Society of Neuropathology.

Directional Migration of Recirculating Lymphocytes through Lymph Nodes via Random Walks

PubMed Central

Thomas, Niclas; Matejovicova, Lenka; Srikusalanukul, Wichat; Shawe-Taylor, John; Chain, Benny

2012-01-01

Naive T lymphocytes exhibit extensive antigen-independent recirculation between blood and lymph nodes, where they may encounter dendritic cells carrying cognate antigen. We examine how long different T cells may spend in an individual lymph node by examining data from long term cannulation of blood and efferent lymphatics of a single lymph node in the sheep. We determine empirically the distribution of transit times of migrating T cells by applying the Least Absolute Shrinkage & Selection Operator () or regularised to fit experimental data describing the proportion of labelled infused cells in blood and efferent lymphatics over time. The optimal inferred solution reveals a distribution with high variance and strong skew. The mode transit time is typically between 10 and 20 hours, but a significant number of cells spend more than 70 hours before exiting. We complement the empirical machine learning based approach by modelling lymphocyte passage through the lymph node . On the basis of previous two photon analysis of lymphocyte movement, we optimised distributions which describe the transit times (first passage times) of discrete one dimensional and continuous (Brownian) three dimensional random walks with drift. The optimal fit is obtained when drift is small, i.e. the ratio of probabilities of migrating forward and backward within the node is close to one. These distributions are qualitatively similar to the inferred empirical distribution, with high variance and strong skew. In contrast, an optimised normal distribution of transit times (symmetrical around mean) fitted the data poorly. The results demonstrate that the rapid recirculation of lymphocytes observed at a macro level is compatible with predominantly randomised movement within lymph nodes, and significant probabilities of long transit times. We discuss how this pattern of migration may contribute to facilitating interactions between low frequency T cells and antigen presenting cells carrying cognate antigen. PMID:23028891

Electrochemical Migration Behavior of Copper-Clad Laminate and Electroless Nickel/Immersion Gold Printed Circuit Boards under Thin Electrolyte Layers

PubMed Central

Yi, Pan; Xiao, Kui; Ding, Kangkang; Dong, Chaofang; Li, Xiaogang

2017-01-01

The electrochemical migration (ECM) behavior of copper-clad laminate (PCB-Cu) and electroless nickel/immersion gold printed circuit boards (PCB-ENIG) under thin electrolyte layers of different thicknesses containing 0.1 M Na2SO4 was studied. Results showed that, under the bias voltage of 12 V, the reverse migration of ions occurred. For PCB-Cu, both copper dendrites and sulfate precipitates were found on the surface of FR-4 (board material) between two plates. Moreover, the Cu dendrite was produced between the two plates and migrated toward cathode. Compared to PCB-Cu, PCB-ENIG exhibited a higher tendency of ECM failure and suffered from seriously short circuit failure under high relative humidity (RH) environment. SKP results demonstrated that surface potentials of the anode plates were greater than those of the cathode plates, and those potentials of the two plates exhibited a descending trend as the RH increased. At the end of the paper, an electrochemical migration corrosion failure model of PCB was proposed. PMID:28772497

Dcdc2 knockout mice display exacerbated developmental disruptions following knockdown of Dcx

PubMed Central

Wang, Yu; Yin, Xiuyin; Rosen, Glenn; Gabel, Lisa; Guadiana, Sarah M.; Sarkisian, Matthew R; Galaburda, Albert M.; LoTurco, Joseph J.

2011-01-01

The dyslexia-associated gene DCDC2 is a member of the DCX family of genes known to play roles in neurogenesis, neuronal migration and differentiation. Here we report the first phenotypic analysis of a Dcdc2 knockout mouse. Comparisons between Dcdc2 knockout mice and wild type littermates revealed no significant differences in neuronal migration, neocortical lamination, neuronal cilliogenesis or dendritic differentiation. Considering previous studies showing genetic interactions and potential functional redundancy among members of the DCX family, we tested whether decreasing Dcx expression by RNAi would differentially impair neurodevelopment in Dcdc2 knockouts and wild type mice. Consistent with this hypothesis, we found that deficits in neuronal migration, and dendritic growth caused by RNAi of Dcx were more severe in Dcdc2 knockouts than in wild type mice with the same transfection. These results indicate that Dcdc2 is not required for neurogenesis, neuronal migration or differentiation in mice, but may have partial functional redundancy with Dcx. PMID:21689730

The polarity protein partitioning-defective 1 (PAR-1) regulates dendritic spine morphogenesis through phosphorylating postsynaptic density protein 95 (PSD-95).

PubMed

Wu, Qian; DiBona, Victoria L; Bernard, Laura P; Zhang, Huaye

2012-08-31

The polarity protein PAR-1 plays an essential role in many cellular contexts, including embryogenesis, asymmetric cell division, directional migration, and epithelial morphogenesis. Despite its known importance in different cellular processes, the role of PAR-1 in neuronal morphogenesis is less well understood. In particular, its role in the morphogenesis of dendritic spines, which are sites of excitatory synaptic inputs, has been unclear. Here, we show that PAR-1 is required for normal spine morphogenesis in hippocampal neurons. We further show that PAR-1 functions through phosphorylating the synaptic scaffolding protein PSD-95 in this process. Phosphorylation at a conserved serine residue in the KXGS motif in PSD-95 regulates spine morphogenesis, and a phosphomimetic mutant of this site can rescue the defects of kinase-dead PAR-1. Together, our findings uncover a role of PAR-1 in spine morphogenesis in hippocampal neurons through phosphorylating PSD-95.

In situ targeting of dendritic cells sets tolerogenic environment and ameliorates CD4+ T-cell response in the postischemic liver.

PubMed

Funken, Dominik; Ishikawa-Ankerhold, Hellen; Uhl, Bernd; Lerchenberger, Maximilian; Rentsch, Markus; Mayr, Doris; Massberg, Steffen; Werner, Jens; Khandoga, Andrej

2017-11-01

CD4 + T cells recruited to the liver play a key role in the pathogenesis of ischemia/reperfusion (I/R) injury. The mechanism of their activation during alloantigen-independent I/R is not completely understood. We hypothesized that liver-resident dendritic cells (DCs) interact with CD4 + T cells in the postischemic liver and that modulation of DCs or T-cell-DC interactions attenuates liver inflammation. In mice, warm hepatic I/R (90/120-240 min) was induced. Tolerogenic DCs were generated in situ by pretreatment of animals with the vitamin D analog paricalcitol. A mAb-CD44 was used for blockade of CD4 + T-cell-DC interactions. As shown by 2-photon in vivo microscopy as well as confocal microscopy, CD4 + T cells were closely colocalized with DCs in the postischemic liver. Pretreatment with paricalcitol attenuated I/R-induced maturation of DCs (flow cytometry), CD4 + T-cell recruitment into the liver (intravital microscopy), and hepatocellular/microvascular damage (intravital microscopy, alanine aminotransferase/aspartate aminotransferase, histology). However, interruption of T-cell-DC interaction increased proinflammatory DC maturation and even enhanced tissue damage. Simultaneous treatment with an anti-CD44mAb completely abolished the beneficial effect of paricalcitol on T-cell migration and tissue injury. Our study demonstrates for the first time that hepatic DCs interact with CD4 + T cells in the postischemic liver in vivo ; modulation of DCs and/or generation of tolerogenic DCs attenuates intrahepatic CD4 + T-cell recruitment and reduces I/R injury; and interruption of CD44-dependent CD4 + T-cell-DC interactions enhances tissue injury by preventing the modulatory effect of hepatic DCs on T cells, especially type 1 T helper effector cells. Thus, hepatic DCs are strongly involved in the promotion of CD4 + T-cell-dependent postischemic liver inflammation.-Funken, D., Ishikawa-Ankerhold, H., Uhl, B., Lerchenberger, M., Rentsch, M., Mayr, D., Massberg, S., Werner, J., Khandoga, A. In situ targeting of dendritic cells sets tolerogenic environment and ameliorates CD4 + T-cell response in the postischemic liver. © FASEB.

p16 expression in follicular dendritic cell sarcoma: a potential mimicker of human papillomavirus-related oropharyngeal squamous cell carcinoma.

PubMed

Zhang, Lingxin; Yang, Chen; Lewis, James S; El-Mofty, Samir K; Chernock, Rebecca D

2017-08-01

Follicular dendritic cell sarcoma is a rare mesenchymal neoplasm that most commonly occurs in cervical lymph nodes. It has histologic and clinical overlap with the much more common p16-positive human papillomavirus (HPV)-related squamous cell carcinoma of the oropharynx, which characteristically has nonkeratinizing morphology and often presents as an isolated neck mass. Not surprisingly, follicular dendritic cell sarcomas are commonly misdiagnosed as squamous cell carcinoma. Immunohistochemistry is helpful in separating the 2 entities. Follicular dendritic cell sarcoma expresses dendritic markers such as CD21 and CD23 and is almost always cytokeratin negative. However, in many cases of HPV-related oropharyngeal carcinoma, only p16 immunohistochemistry as a prognostic and surrogate marker for HPV is performed. p16 expression in follicular dendritic cell sarcoma has not been characterized. Here, we investigate the expression of p16 in follicular dendritic cell sarcoma and correlate it with retinoblastoma protein expression. A pilot study of dendritic marker expression in HPV-related oropharyngeal squamous cell carcinoma was also performed. We found that 4 of 8 sarcomas expressed p16 with strong and diffuse staining in 2 cases. In 2 of the 4 cases, p16 expression corresponded to loss of retinoblastoma protein expression. Dendritic marker expression (CD21 and CD23) was not found in HPV-related oropharyngeal squamous cell carcinomas. As such, positive p16 immunohistochemistry cannot be used as supportive evidence for the diagnosis of squamous cell carcinoma as strong and diffuse p16 expression may also occur in follicular dendritic cell sarcoma. Cytokeratins and dendritic markers are critical in separating the two tumor types. Copyright © 2017 Elsevier Inc. All rights reserved.

Enhanced cytotoxic activity of effector T-cells against cholangiocarcinoma by dendritic cells pulsed with pooled mRNA.

PubMed

Junking, Mutita; Grainok, Janya; Thepmalee, Chutamas; Wongkham, Sopit; Yenchitsomanus, Pa-Thai

2017-10-01

Cholangiocarcinoma is a malignancy of bile duct epithelia with an increasing in incidence rate worldwide. Surgery is the only curative treatment, while adjuvant chemotherapy and radiotherapy render poor responses. Cell-based immunotherapy is a potential strategy for cholangiocarcinoma treatment. However, variation of tumor antigens in cholangiocarcinoma leads to the ineffectiveness of cell-based immunotherapy. In this study, we examined the activation of effector T-cells by dendritic cells pulsed with protein lysate or total RNA from cholangiocarcinoma cell lines for their cytolytic activity against cholangiocarcinoma. Broad-spectrum antigen types with respect to RNA antigen sources were obtained from combination of three cholangiocarcinoma cell lines (KKU-213, KKU-100, and KKU-055). Compared with protein lysate-pulsed dendritic cells, total RNA-pulsed dendritic cells induced anti-tumor effector T-cell response with higher killing ability to KKU-100 and KKU-213 cells compared with protein lysate-pulsed dendritic cells. Moreover, pooled messenger RNA from three cholangiocarcinoma cell lines significantly increased the specific killing capacity of activated lymphocytes against KKU-213 cells. These results suggest that activation of anti-tumor effector T-cells against cholangiocarcinoma by RNA-pulsed dendritic cells is more effective than that by protein lysate-pulsed dendritic cells. In addition, pulsing dendritic cells with pooled messenger RNA from multiple cell lines enhanced the efficacy of a cellular immune response against cholangiocarcinoma.

Isolation of Human Skin Dendritic Cell Subsets.

PubMed

Gunawan, Merry; Jardine, Laura; Haniffa, Muzlifah

2016-01-01

Dendritic cells (DCs) are specialized leukocytes with antigen-processing and antigen-presenting functions. DCs can be divided into distinct subsets by anatomical location, phenotype and function. In human, the two most accessible tissues to study leukocytes are peripheral blood and skin. DCs are rare in human peripheral blood (<1 % of mononuclear cells) and have a less mature phenotype than their tissue counterparts (MacDonald et al., Blood. 100:4512-4520, 2002; Haniffa et al., Immunity 37:60-73, 2012). In contrast, the skin covering an average total surface area of 1.8 m(2) has approximately tenfold more DCs than the average 5 L of total blood volume (Wang et al., J Invest Dermatol 134:965-974, 2014). DCs migrate spontaneously from skin explants cultured ex vivo, which provide an easy method of cell isolation (Larsen et al., J Exp Med 172:1483-1493, 1990; Lenz et al., J Clin Invest 92:2587-2596, 1993; Nestle et al., J Immunol 151:6535-6545, 1993). These factors led to the extensive use of skin DCs as the "prototype" migratory DCs in human studies. In this chapter, we detail the protocols to isolate DCs and resident macrophages from human skin. We also provide a multiparameter flow cytometry gating strategy to identify human skin DCs and to distinguish them from macrophages.

Different protein of Echinococcus granulosus stimulates dendritic induced immune response.

PubMed

Wang, Yana; Wang, Qiang; Lv, Shiyu; Zhang, Shengxiang

2015-06-01

Cystic echinococcosis is a chronic infectious disease that results from a host/parasite interaction. Vaccination with ferritin derived from Echinococcus granulosus is a potential preventative treatment. To understand whether ferritin is capable of inducing a host immune response, we investigated the response of dendritic cells (DCs) to both recombinant ferritin protein and the hydatid fluid (HF) of E. granulosus. We evaluated the immunomodulatory potential of these antigens by performing, immunocytochemistry, electron microscopy and in vivo imaging of monocyte-derived murine DCs. During antigen stimulation of DCs, ferritin cause DCs maturation and induced higher levels of surface marker expression and activated T-cell proliferation and migration. On contrary, HF failed to induce surface marker expression and to stimulate T-cell proliferation. In response to HF, DCs produced interleukin-6 (IL-6), but no IL-12 and IL-10. DCs stimulated with ferritin produced high levels of cytokines. Overall, HF appears to induce host immunosuppression in order to ensure parasite survival via inhibits DC maturation and promotes Th2-dependent secretion of cytokines. Although ferritin also promoted DC maturation and cytokine release, it also activates CD4+T-cell proliferation, but regard of the mechanism of the Eg.ferritin induce host to eradicate E. granulosus were not clear.

Flt3L controls the development of radiosensitive dendritic cells in the meninges and choroid plexus of the steady-state mouse brain

PubMed Central

Anandasabapathy, Niroshana; Victora, Gabriel D.; Meredith, Matthew; Feder, Rachel; Dong, Baojun; Kluger, Courtney; Yao, Kaihui; Dustin, Michael L.; Nussenzweig, Michel C.; Steinman, Ralph M.

2011-01-01

Antigen-presenting cells in the disease-free brain have been identified primarily by expression of antigens such as CD11b, CD11c, and MHC II, which can be shared by dendritic cells (DCs), microglia, and monocytes. In this study, starting with the criterion of Flt3 (FMS-like receptor tyrosine kinase 3)-dependent development, we characterize the features of authentic DCs within the meninges and choroid plexus in healthy mouse brains. Analyses of morphology, gene expression, and antigen-presenting function established a close relationship between meningeal and choroid plexus DCs (m/chDCs) and spleen DCs. DCs in both sites shared an intrinsic requirement for Flt3 ligand. Microarrays revealed differences in expression of transcripts encoding surface molecules, transcription factors, pattern recognition receptors, and other genes in m/chDCs compared with monocytes and microglia. Migrating pre-DC progenitors from bone marrow gave rise to m/chDCs that had a 5–7-d half-life. In contrast to microglia, DCs actively present self-antigens and stimulate T cells. Therefore, the meninges and choroid plexus of a steady-state brain contain DCs that derive from local precursors and exhibit a differentiation and antigen-presenting program similar to spleen DCs and distinct from microglia. PMID:21788405

Flt3L controls the development of radiosensitive dendritic cells in the meninges and choroid plexus of the steady-state mouse brain.

PubMed

Anandasabapathy, Niroshana; Victora, Gabriel D; Meredith, Matthew; Feder, Rachel; Dong, Baojun; Kluger, Courtney; Yao, Kaihui; Dustin, Michael L; Nussenzweig, Michel C; Steinman, Ralph M; Liu, Kang

2011-08-01

Antigen-presenting cells in the disease-free brain have been identified primarily by expression of antigens such as CD11b, CD11c, and MHC II, which can be shared by dendritic cells (DCs), microglia, and monocytes. In this study, starting with the criterion of Flt3 (FMS-like receptor tyrosine kinase 3)-dependent development, we characterize the features of authentic DCs within the meninges and choroid plexus in healthy mouse brains. Analyses of morphology, gene expression, and antigen-presenting function established a close relationship between meningeal and choroid plexus DCs (m/chDCs) and spleen DCs. DCs in both sites shared an intrinsic requirement for Flt3 ligand. Microarrays revealed differences in expression of transcripts encoding surface molecules, transcription factors, pattern recognition receptors, and other genes in m/chDCs compared with monocytes and microglia. Migrating pre-DC progenitors from bone marrow gave rise to m/chDCs that had a 5-7-d half-life. In contrast to microglia, DCs actively present self-antigens and stimulate T cells. Therefore, the meninges and choroid plexus of a steady-state brain contain DCs that derive from local precursors and exhibit a differentiation and antigen-presenting program similar to spleen DCs and distinct from microglia.

Three-dimensional culture and interaction of cancer cells and dendritic cells in an electrospun nano-submicron hybrid fibrous scaffold

PubMed Central

Kim, Tae-Eon; Kim, Chang Gun; Kim, Jin Soo; Jin, Songwan; Yoon, Sik; Bae, Hae-Rahn; Kim, Jeong-Hwa; Jeong, Young Hun; Kwak, Jong-Young

2016-01-01

An artificial three-dimensional (3D) culture system that mimics the tumor microenvironment in vitro is an essential tool for investigating the cross-talk between immune and cancer cells in tumors. In this study, we developed a 3D culture system using an electrospun poly(ε-caprolactone) (PCL) nanofibrous scaffold (NFS). A hybrid NFS containing an uninterrupted network of nano- and submicron-scale fibers (400 nm to 2 µm) was generated by deposition onto a stainless steel mesh instead of an aluminum plate. The hybrid NFS contained multiplanar pores in a 3D structure. Surface-seeded mouse CT26 colon cancer cells and bone marrow-derived dendritic cells (BM-DCs) were able to infiltrate the hybrid NFS within several hours. BM-DCs cultured on PCL nanofibers showed a baseline inactive form, and lipopolysaccharide (LPS)-activated BM-DCs showed increased expression of CD86 and major histocompatibility complex Class II. Actin and phosphorylated FAK were enriched where unstimulated and LPS-stimulated BM-DCs contacted the fibers in the 3D hybrid NFS. When BM-DCs were cocultured with mitoxantrone-treated CT26 cells in a 3D hybrid NFS, BM-DCs sprouted cytoplasm to, migrated to, synapsed with, and engulfed mitoxantrone-treated CT26 cancer cells, which were similar to the naturally occurring cross-talk between these two types of cells. The 3D hybrid NFS developed here provides a 3D structure for coculture of cancer and immune cells. PMID:27042051

Three-dimensional culture and interaction of cancer cells and dendritic cells in an electrospun nano-submicron hybrid fibrous scaffold.

PubMed

Kim, Tae-Eon; Kim, Chang Gun; Kim, Jin Soo; Jin, Songwan; Yoon, Sik; Bae, Hae-Rahn; Kim, Jeong-Hwa; Jeong, Young Hun; Kwak, Jong-Young

2016-01-01

An artificial three-dimensional (3D) culture system that mimics the tumor microenvironment in vitro is an essential tool for investigating the cross-talk between immune and cancer cells in tumors. In this study, we developed a 3D culture system using an electrospun poly(ε-caprolactone) (PCL) nanofibrous scaffold (NFS). A hybrid NFS containing an uninterrupted network of nano- and submicron-scale fibers (400 nm to 2 µm) was generated by deposition onto a stainless steel mesh instead of an aluminum plate. The hybrid NFS contained multiplanar pores in a 3D structure. Surface-seeded mouse CT26 colon cancer cells and bone marrow-derived dendritic cells (BM-DCs) were able to infiltrate the hybrid NFS within several hours. BM-DCs cultured on PCL nanofibers showed a baseline inactive form, and lipopolysaccharide (LPS)-activated BM-DCs showed increased expression of CD86 and major histocompatibility complex Class II. Actin and phosphorylated FAK were enriched where unstimulated and LPS-stimulated BM-DCs contacted the fibers in the 3D hybrid NFS. When BM-DCs were cocultured with mitoxantrone-treated CT26 cells in a 3D hybrid NFS, BM-DCs sprouted cytoplasm to, migrated to, synapsed with, and engulfed mitoxantrone-treated CT26 cancer cells, which were similar to the naturally occurring cross-talk between these two types of cells. The 3D hybrid NFS developed here provides a 3D structure for coculture of cancer and immune cells.

Absence of LTB4/BLT1 axis facilitates generation of mouse GM-CSF-induced long-lasting antitumor immunologic memory by enhancing innate and adaptive immune systems.

PubMed

Yokota, Yosuke; Inoue, Hiroyuki; Matsumura, Yumiko; Nabeta, Haruka; Narusawa, Megumi; Watanabe, Ayumi; Sakamoto, Chika; Hijikata, Yasuki; Iga-Murahashi, Mutsunori; Takayama, Koichi; Sasaki, Fumiyuki; Nakanishi, Yoichi; Yokomizo, Takehiko; Tani, Kenzaburo

2012-10-25

BLT1 is a high-affinity receptor for leukotriene B4 (LTB4) that is a potent lipid chemoattractant for myeloid leukocytes. The role of LTB4/BLT1 axis in tumor immunology, including cytokine-based tumor vaccine, however, remains unknown. We here demonstrated that BLT1-deficient mice rejected subcutaneous tumor challenge of GM-CSF gene-transduced WEHI3B (WGM) leukemia cells (KO/WGM) and elicited robust antitumor responses against second tumor challenge with WEHI3B cells. During GM-CSF-induced tumor regression, the defective LTB4/BLT1 signaling significantly reduced tumor-infiltrating myeloid-derived suppressor cells, increased the maturation status of dendritic cells in tumor tissues, enhanced their CD4(+) T-cell stimulation capacity and migration rate of dendritic cells that had phagocytosed tumor-associated antigens into tumor-draining lymph nodes, suggesting a positive impact on GM-CSF-sensitized innate immunity. Furthermore, KO/WGM mice displayed activated adaptive immunity by attenuating regulatory CD4(+) T subsets and increasing numbers of Th17 and memory CD44(hi)CD4(+) T subsets, both of which elicited superior antitumor effects as evidenced by adoptive cell transfer. In vivo depletion assays also revealed that CD4(+) T cells were the main effectors of the persistent antitumor immunity. Our data collectively underscore a negative role of LTB4/BLT1 signaling in effective generation and maintenance of GM-CSF-induced antitumor memory CD4(+) T cells.

Reelin Regulates the Maturation of Dendritic Spines, Synaptogenesis and Glial Ensheathment of Newborn Granule Cells

PubMed Central

Bosch, Carles; Masachs, Nuria; Exposito-Alonso, David; Martínez, Albert; Teixeira, Cátia M.; Fernaud, Isabel; Pujadas, Lluís; Ulloa, Fausto; Comella, Joan X.; DeFelipe, Javier; Merchán-Pérez, Angel; Soriano, Eduardo

2016-01-01

The Reelin pathway is essential for both neural migration and for the development and maturation of synaptic connections. However, its role in adult synaptic formation and remodeling is still being investigated. Here, we investigated the impact of the Reelin/Dab1 pathway on the synaptogenesis of newborn granule cells (GCs) in the young-adult mouse hippocampus. We show that neither Reelin overexpression nor the inactivation of its intracellular adapter, Dab1, substantially alters dendritic spine numbers in these neurons. In contrast, 3D-electron microscopy (focused ion beam milling/scanning electron microscope) revealed that dysregulation of the Reelin/Dab1 pathway leads to both transient and permanent changes in the types and morphology of dendritic spines, mainly altering mushroom, filopodial, and branched GC spines. We also found that the Reelin/Dab1 pathway controls synaptic configuration of presynaptic boutons in the dentate gyrus, with its dysregulation leading to a substantial decrease in multi-synaptic bouton innervation. Lastly, we show that the Reelin/Dab1 pathway controls astroglial ensheathment of synapses. Thus, the Reelin pathway is a key regulator of adult-generated GC integration, by controlling dendritic spine types and shapes, their synaptic innervation patterns, and glial ensheathment. These findings may help to better understanding of hippocampal circuit alterations in neurological disorders in which the Reelin pathway is implicated. Significance Statement The extracellular protein Reelin has an important role in neurological diseases, including epilepsy, Alzheimer's disease and psychiatric diseases, targeting hippocampal circuits. Here we address the role of Reelin in the development of synaptic contacts in adult-generated granule cells (GCs), a neuronal population that is crucial for learning and memory and implicated in neurological and psychiatric diseases. We found that the Reelin pathway controls the shapes, sizes, and types of dendritic spines, the complexity of multisynaptic innervations and the degree of the perisynaptic astroglial ensheathment that controls synaptic homeostasis. These findings show a pivotal role of Reelin in GC synaptogenesis and provide a foundation for structural circuit alterations caused by Reelin deregulation that may occur in neurological and psychiatric disorders. PMID:27624722

Ursolic acid isolated from Uncaria rhynchophylla activates human dendritic cells via TLR2 and/or TLR4 and induces the production of IFN-gamma by CD4+ naïve T cells.

PubMed

Jung, Tae-Young; Pham, Thanh Nhan Nguyen; Umeyama, Akemi; Shoji, Noboru; Hashimoto, Toshihiro; Lee, Je-Jung; Takei, Masao

2010-09-25

Ursolic acid is triterpene isolated from Uncaria rhynchophylla and is a pharmacologically active substance. The induction of dendritic cell maturation is critical for the induction of Ag-specific T-lymphocyte response and may be essential for the development of human vaccine relying on T cell immunity. In this study, we investigated that the effect of Ursolic acid on the phenotypic and functional maturation of human monocyte-derived dendritic cells in vitro. Dendritic cells harvested on day 8 were examined using functional assay. The expression levels of CD1a, CD80, CD83, CD86, HLA-DR and CCR7 on Ursolic acid-primed dendritic cells was slightly enhanced. Ursolic acid dose-dependently enhanced the T cell stimulatory capacity in an allogeneic mixed lymphocyte reaction, as measured by T cell proliferation. The production of IL-12p70 induced by Ursolic acid-primed dendritic cells was inhibited by the anti-Toll-like receptor-2 (TLR2) mAb and anti-TLR4 mAb. Moreover, Ursolic acid-primed dendritic cells expressed levels of mRNA coding for both TLR2 and TLR4. The majority of cells produced considerable interferon-gamma (IFN-gamma), but also small amounts of interleukin (IL-4)-4. Ursolic acid-primed dendritic cells have an intermediate migratory capacity towards CCL19 and CCL21. These results suggest that Ursolic acid modulates human dendritic cells function in a fashion that favors Th1 polarization via the activation of IL-12p70 dependent on TLR2 and/or TLR4, and may be used on dendritic cells-based vaccines for cancer immunotherapy. 2010 Elsevier B.V. All rights reserved.

Generation of large numbers of dendritic cells from mouse bone marrow cultures supplemented with granulocyte/macrophage colony-stimulating factor

PubMed Central

1992-01-01

Antigen-presenting, major histocompatibility complex (MHC) class II- rich dendritic cells are known to arise from bone marrow. However, marrow lacks mature dendritic cells, and substantial numbers of proliferating less-mature cells have yet to be identified. The methodology for inducing dendritic cell growth that was recently described for mouse blood now has been modified to MHC class II- negative precursors in marrow. A key step is to remove the majority of nonadherent, newly formed granulocytes by gentle washes during the first 2-4 d of culture. This leaves behind proliferating clusters that are loosely attached to a more firmly adherent "stroma." At days 4-6 the clusters can be dislodged, isolated by 1-g sedimentation, and upon reculture, large numbers of dendritic cells are released. The latter are readily identified on the basis of their distinct cell shape, ultrastructure, and repertoire of antigens, as detected with a panel of monoclonal antibodies. The dendritic cells express high levels of MHC class II products and act as powerful accessory cells for initiating the mixed leukocyte reaction. Neither the clusters nor mature dendritic cells are generated if macrophage colony-stimulating factor rather than granulocyte/macrophage colony-stimulating factor (GM-CSF) is applied. Therefore, GM-CSF generates all three lineages of myeloid cells (granulocytes, macrophages, and dendritic cells). Since > 5 x 10(6) dendritic cells develop in 1 wk from precursors within the large hind limb bones of a single animal, marrow progenitors can act as a major source of dendritic cells. This feature should prove useful for future molecular and clinical studies of this otherwise trace cell type. PMID:1460426

Commensal oral bacteria antigens prime human dendritic cells to induce Th1, Th2 or Treg differentiation.

PubMed

Kopitar, A N; Ihan Hren, N; Ihan, A

2006-02-01

In various immunopathologic conditions, bacterial flora induce an immune response which results in inflammatory manifestations, e.g. periapical granuloma. Dendritic cells provide the main orchestration of specific immune responses. The aim of our study was to test the capacity of distinct oral bacterial antigens (prepared from Streptococcus mitis, Propionibacterium acnes, and Bacteroides spp.) to prime human dendritic cells for stimulation of the T-lymphocyte response. To assess the T-lymphocyte response, the expression of CD25, CD69, intracellular interferon gamma (cIFN-gamma), and intracellular interleukin 4 (cIL-4) was determined. Dendritic cells were prepared from leukocyte buffy coat from healthy blood donors. Monocytes were stimulated with IL-4 and GM-CSF and dendritic cells activated with bacterial lysates. Cell suspensions contained up to 90% dendritic cells, which represented 2-12% of the initial number of mononuclear cells. Lymphocyte subsets that developed in lymphocyte cultures after 1 week of stimulation were analyzed by flow cytometry. Dendritic cells, primed with antigens of Bacteroides fragilis have shown significantly higher activation and expression of intercellular IFN-gamma by T lymphocytes compared to negative controls. The dendritic cells primed with antigens of P. acnes had no effect on T-lymphocyte activation or cytokine production; instead they induced differentiation of T lymphocytes into CD25bright cells (regulatory T cells) with a potentially inhibitory effect on immune response. Dendritic cells primed with antigens of S. mitis induced increased expression of cIL-4. We conclude that commensal oral bacteria antigens prepared from B. fragilis, S. mitis, and P. acnes prime human dendritic cells to induce Th1, Th2, and T(reg) differentiation, respectively. This may advance our understanding of immunopathologic manifestations in the oral cavity and offer new possibilities for redirecting immune responses in mucosal vaccination.

Decreased number of interneurons and increased seizures in neuropilin 2 deficient mice: Implications for autism and epilepsy

PubMed Central

Gant, John C.; Thibault, Oliver; Blalock, Eric M.; Yang, Jun; Bachstetter, Adam; Kotick, James; Schauwecker, Paula E.; Hauser, Kurt F.; Smith, George M.; Mervis, Ron; Li, YanFang; Barnes, Gregory N.

2010-01-01

Summary Purpose Clinically, perturbations in the semaphorin signaling system have been associated with autism and epilepsy. The semaphorins have been implicated in guidance, migration, differentiation, and synaptic plasticity of neurons. The semaphorin 3F (Sema3F) ligand and its receptor, neuropilin 2 (NPN2) are highly expressed within limbic areas. NPN2 signaling may intimately direct the apposition of presynaptic and postsynaptic locations, facilitating the development and maturity of hippocampal synaptic function. To further understand the role of NPN2 signaling in central nevous system (CNS) plasticity, structural and functional alterations were assessed in NPN2 deficient mice. Methods In NPN2 deficient mice, we measured seizure susceptibility after kainic acid or pentylenetetrazol, neuronal excitability and synaptic throughput in slice preparations, principal and interneuron cell counts with immunocytochemical protocols, synaptosomal protein levels with immunoblots, and dendritic morphology with Golgi-staining. Results NPN2 deficient mice had shorter seizure latencies, increased vulnerability to seizure-related death, were more likely to develop spontaneous recurrent seizure activity after chemical challenge, and had an increased slope on input/output curves. Principal cell counts were unchanged, but GABA, parvalbumin, and neuropeptide Y interneuron cell counts were significantly reduced. Synaptosomal NPN2 protein levels and total number of GABAergic synapses were decreased in a gene dose-dependent fashion. CA1 pyramidal cells showed reduced dendritic length and complexity, as well as an increased number of dendritic spines. Discussion These data suggest the novel hypothesis that the Sema 3F signaling system's role in appropriate placement of subsets of hippocampal interneurons has critical downstream consequences for hippocampal function, resulting in a more seizure susceptible phenotype. PMID:18657176

Brucella discriminates between mouse dendritic cell subsets upon in vitro infection.

PubMed

Papadopoulos, Alexia; Gagnaire, Aurélie; Degos, Clara; de Chastellier, Chantal; Gorvel, Jean-Pierre

2016-01-01

Brucella is a Gram-negative bacterium responsible for brucellosis, a worldwide re-emerging zoonosis. Brucella has been shown to infect and replicate within Granulocyte macrophage colony-stimulating factor (GMCSF) in vitro grown bone marrow-derived dendritic cells (BMDC). In this cell model, Brucella can efficiently control BMDC maturation. However, it has been shown that Brucella infection in vivo induces spleen dendritic cells (DC) migration and maturation. As DCs form a complex network composed by several subpopulations, differences observed may be due to different interactions between Brucella and DC subsets. Here, we compare Brucella interaction with several in vitro BMDC models. The present study shows that Brucella is capable of replicating in all the BMDC models tested with a high infection rate at early time points in GMCSF-IL15 DCs and Flt3l DCs. GMCSF-IL15 DCs and Flt3l DCs are more activated than the other studied DC models and consequently intracellular bacteria are not efficiently targeted to the ER replicative niche. Interestingly, GMCSF-DC and GMCSF-Flt3l DC response to infection is comparable. However, the key difference between these 2 models concerns IL10 secretion by GMCSF DCs observed at 48 h post-infection. IL10 secretion can explain the weak secretion of IL12p70 and TNFα in the GMCSF-DC model and the low level of maturation observed when compared to GMCSF-IL15 DCs and Flt3l DCs. These models provide good tools to understand how Brucella induce DC maturation in vivo and may lead to new therapeutic design using DCs as cellular vaccines capable of enhancing immune response against pathogens.

Microbiota induces tonic CCL2 systemic levels that control pDC trafficking in steady state.

PubMed

Swiecki, M; Miller, H L; Sesti-Costa, R; Cella, M; Gilfillan, S; Colonna, M

2017-07-01

Plasmacytoid dendritic cells (pDCs) detect viruses initiating antiviral type I interferon responses. The microbiota is known to shape immune responses, but whether it influences pDC homeostasis and/or function is poorly understood. By comparing pDCs in germ-free and specific pathogen-free mice, we found that the microbiota supports homeostatic trafficking by eliciting constitutive levels of the chemokine CCL2 that engages CCR2. Mononuclear phagocytes were required for tonic CCL2 levels. CCL2 was particularly important for trafficking of a CCR2 hi subset of pDCs that produced proinflammatory cytokines and was prone to apoptosis. We further demonstrated that CCR2 was also essential for pDC migration during inflammation. Wild-type (WT):Ccr2 -/- mixed bone marrow chimeras revealed that CCR2 promotes pDC migration in a cell-intrinsic manner. Overall, we identify a novel role for the microbiota in shaping immunity, which includes induction of CCL2 levels that control homeostatic trafficking of pDCs.

Trim9 Deletion Alters the Morphogenesis of Developing and Adult-Born Hippocampal Neurons and Impairs Spatial Learning and Memory

PubMed Central

Winkle, Cortney C.; Olsen, Reid H. J.; Kim, Hyojin; Moy, Sheryl S.

2016-01-01

During hippocampal development, newly born neurons migrate to appropriate destinations, extend axons, and ramify dendritic arbors to establish functional circuitry. These developmental stages are recapitulated in the dentate gyrus of the adult hippocampus, where neurons are continuously generated and subsequently incorporate into existing, local circuitry. Here we demonstrate that the E3 ubiquitin ligase TRIM9 regulates these developmental stages in embryonic and adult-born mouse hippocampal neurons in vitro and in vivo. Embryonic hippocampal and adult-born dentate granule neurons lacking Trim9 exhibit several morphological defects, including excessive dendritic arborization. Although gross anatomy of the hippocampus was not detectably altered by Trim9 deletion, a significant number of Trim9−/− adult-born dentate neurons localized inappropriately. These morphological and localization defects of hippocampal neurons in Trim9−/− mice were associated with extreme deficits in spatial learning and memory, suggesting that TRIM9-directed neuronal morphogenesis may be involved in hippocampal-dependent behaviors. SIGNIFICANCE STATEMENT Appropriate generation and incorporation of adult-born neurons in the dentate gyrus are critical for spatial learning and memory and other hippocampal functions. Here we identify the brain-enriched E3 ubiquitin ligase TRIM9 as a novel regulator of embryonic and adult hippocampal neuron shape acquisition and hippocampal-dependent behaviors. Genetic deletion of Trim9 elevated dendritic arborization of hippocampal neurons in vitro and in vivo. Adult-born dentate granule cells lacking Trim9 similarly exhibited excessive dendritic arborization and mislocalization of cell bodies in vivo. These cellular defects were associated with severe deficits in spatial learning and memory. PMID:27147649

Trim9 Deletion Alters the Morphogenesis of Developing and Adult-Born Hippocampal Neurons and Impairs Spatial Learning and Memory.

PubMed

Winkle, Cortney C; Olsen, Reid H J; Kim, Hyojin; Moy, Sheryl S; Song, Juan; Gupton, Stephanie L

2016-05-04

During hippocampal development, newly born neurons migrate to appropriate destinations, extend axons, and ramify dendritic arbors to establish functional circuitry. These developmental stages are recapitulated in the dentate gyrus of the adult hippocampus, where neurons are continuously generated and subsequently incorporate into existing, local circuitry. Here we demonstrate that the E3 ubiquitin ligase TRIM9 regulates these developmental stages in embryonic and adult-born mouse hippocampal neurons in vitro and in vivo Embryonic hippocampal and adult-born dentate granule neurons lacking Trim9 exhibit several morphological defects, including excessive dendritic arborization. Although gross anatomy of the hippocampus was not detectably altered by Trim9 deletion, a significant number of Trim9(-/-) adult-born dentate neurons localized inappropriately. These morphological and localization defects of hippocampal neurons in Trim9(-/-) mice were associated with extreme deficits in spatial learning and memory, suggesting that TRIM9-directed neuronal morphogenesis may be involved in hippocampal-dependent behaviors. Appropriate generation and incorporation of adult-born neurons in the dentate gyrus are critical for spatial learning and memory and other hippocampal functions. Here we identify the brain-enriched E3 ubiquitin ligase TRIM9 as a novel regulator of embryonic and adult hippocampal neuron shape acquisition and hippocampal-dependent behaviors. Genetic deletion of Trim9 elevated dendritic arborization of hippocampal neurons in vitro and in vivo Adult-born dentate granule cells lacking Trim9 similarly exhibited excessive dendritic arborization and mislocalization of cell bodies in vivo These cellular defects were associated with severe deficits in spatial learning and memory. Copyright © 2016 the authors 0270-6474/16/364940-19$15.00/0.

Secondary allergic T cell responses are regulated by dendritic cell-derived thrombospondin-1 in the setting of allergic eye disease.

PubMed

Smith, R E; Reyes, N J; Khandelwal, P; Schlereth, S L; Lee, H S; Masli, S; Saban, D R

2016-08-01

Allergic eye disease, as in most forms of atopy, ranges in severity among individuals from immediate hypersensitivity to a severe and debilitating chronic disease. Dendritic cells play a key role in stimulating pathogenic T cells in allergen re-exposure, or secondary responses. However, molecular cues by dendritic cells underpinning allergic T cell response levels and the impact that this control has on consequent severity of allergic disease are poorly understood. Here, we show that a deficiency in thrombospondin-1, a matricellular protein known to affect immune function, has subsequent effects on downstream T cell responses during allergy, as revealed in an established mouse model of allergic eye disease. More specifically, we demonstrate that a thrombospondin-1 deficiency specific to dendritic cells leads to heightened secondary T cell responses and consequent clinical disease. Interestingly, whereas thrombospondin-1-deficient dendritic cells augmented activity of allergen-primed T cells, this increase was not recapitulated with naïve T cells in vitro. The role of dendritic cell-derived thrombospondin-1 in regulating secondary allergic T cell responses was confirmed in vivo, as local transfer of thrombospondin-1-sufficient dendritic cells to the ocular mucosa of thrombospondin-1 null hosts prevented the development of augmented secondary T cell responses and heightened allergic eye disease clinical responses. Finally, we demonstrate that topical instillation of thrombospondin-1-derived peptide reduces T cell activity and clinical progression of allergic eye disease. Taken together, this study reveals an important modulatory role of dendritic cell-derived thrombospondin-1 on secondary allergic T cell responses and suggests the possible dysregulation of dendritic cell-derived thrombospondin-1 expression as a factor in allergic eye disease severity. © Society for Leukocyte Biology.

Secondary allergic T cell responses are regulated by dendritic cell-derived thrombospondin-1 in the setting of allergic eye disease

PubMed Central

Smith, R. E.; Reyes, N. J.; Khandelwal, P.; Schlereth, S. L.; Lee, H. S.; Masli, S.; Saban, D. R.

2016-01-01

Allergic eye disease, as in most forms of atopy, ranges in severity among individuals from immediate hypersensitivity to a severe and debilitating chronic disease. Dendritic cells play a key role in stimulating pathogenic T cells in allergen re-exposure, or secondary responses. However, molecular cues by dendritic cells underpinning allergic T cell response levels and the impact that this control has on consequent severity of allergic disease are poorly understood. Here, we show that a deficiency in thrombospondin-1, a matricellular protein known to affect immune function, has subsequent effects on downstream T cell responses during allergy, as revealed in an established mouse model of allergic eye disease. More specifically, we demonstrate that a thrombospondin-1 deficiency specific to dendritic cells leads to heightened secondary T cell responses and consequent clinical disease. Interestingly, whereas thrombospondin-1-deficient dendritic cells augmented activity of allergen-primed T cells, this increase was not recapitulated with naïve T cells in vitro. The role of dendritic cell-derived thrombospondin-1 in regulating secondary allergic T cell responses was confirmed in vivo, as local transfer of thrombospondin-1-sufficient dendritic cells to the ocular mucosa of thrombospondin-1 null hosts prevented the development of augmented secondary T cell responses and heightened allergic eye disease clinical responses. Finally, we demonstrate that topical instillation of thrombospondin-1-derived peptide reduces T cell activity and clinical progression of allergic eye disease. Taken together, this study reveals an important modulatory role of dendritic cell-derived thrombospondin-1 on secondary allergic T cell responses and suggests the possible dysregulation of dendritic cell-derived thrombospondin-1 expression as a factor in allergic eye disease severity. PMID:26856994

A portrait of a sucker using landscape genetics: how colonization and life history undermine the idealized dendritic metapopulation.

PubMed

Salisbury, Sarah J; McCracken, Gregory R; Keefe, Donald; Perry, Robert; Ruzzante, Daniel E

2016-09-01

Dendritic metapopulations have been attributed unique properties by in silico studies, including an elevated genetic diversity relative to a panmictic population of equal total size. These predictions have not been rigorously tested in nature, nor has there been full consideration of the interacting effects among contemporary landscape features, colonization history and life history traits of the target species. We tested for the effects of dendritic structure as well as the relative importance of life history, environmental barriers and historical colonization on the neutral genetic structure of a longnose sucker (Catostomus catostomus) metapopulation in the Kogaluk watershed of northern Labrador, Canada. Samples were collected from eight lakes, genotyped with 17 microsatellites, and aged using opercula. Lakes varied in differentiation, historical and contemporary connectivity, and life history traits. Isolation by distance was detected only by removing two highly genetically differentiated lakes, suggesting a lack of migration-drift equilibrium and the lingering influence of historical factors on genetic structure. Bayesian analyses supported colonization via the Kogaluk's headwaters. The historical concentration of genetic diversity in headwaters inferred by this result was supported by high historical and contemporary effective sizes of the headwater lake, T-Bone. Alternatively, reduced allelic richness in headwaters confirmed the dendritic structure's influence on gene flow, but this did not translate to an elevated metapopulation effective size. A lack of equilibrium and upstream migration may have dampened the effects of dendritic structure. We suggest that interacting historical and contemporary factors prevent the achievement of the idealized traits of a dendritic metapopulation in nature. © 2016 John Wiley & Sons Ltd.

Regulation of dendritic cell function by insulin/IGF-1/PI3K/Akt signaling through klotho expression.

PubMed

Xuan, Nguyen Thi; Hoang, Nguyen Huy; Nhung, Vu Phuong; Duong, Nguyen Thuy; Ha, Nguyen Hai; Hai, Nong Van

2017-06-01

Insulin or insulin-like growth factor 1 (IGF-1) promotes the activation of phosphoinositide 3 kinase (PI3K)/Akt signaling in immune cells including dendritic cells (DCs), the most potent professional antigen-presenting cells for naive T cells. Klotho, an anti-aging protein, participates in the regulation of the PI3K/Akt signaling, thus the Ca 2+ -dependent migration is reduced in klotho-deficient DCs. The present study explored the effects of insulin/IGF-1 on DC function through klotho expression. To this end, the mouse bone marrow cells were isolated and cultured with GM-CSF to attain bone marrow-derived DCs (BMDCs). Cells were treated with insulin or IGF-1 and followed by stimulating with lipopolysaccharides (LPS). Tumor necrosis factor (TNF)-α formation was examined by enzyme-linked immunosorbent assay (ELISA). Phagocytosis was analyzed by FITC-dextran uptake assay. The expression of klotho was determined by quantitative PCR, immunoprecipitation and western blotting. As a result, treatment of the cells with insulin/IGF-1 resulted in reducing the klotho expression as well as LPS-stimulated TNF-α release and increasing the FITC-dextran uptake but unaltering reactive oxygen species (ROS) production in BMDCs. The effects were abolished by using pharmacological inhibition of PI3K/Akt with LY294002 and paralleled by transfecting DCs with klotho siRNA. In conclusion, the regulation of klotho sensitive DC function by IGF-1 or insulin is mediated through PI3K/Akt signaling pathway in BMDCs.

LPS-treated bone marrow-derived dendritic cells induce immune tolerance through modulating differentiation of CD4+ regulatory T cell subpopulations mediated by 3G11 and CD127.

PubMed

Zhou, Fang; Zhang, Guang-Xian; Rostami, Abdolmohamad

2017-06-01

Intravenous transfer of LPS-treated bone marrow-derived dendritic cells blocks development of autoimmunity induced by CD4 + T cells in vivo. However, cellular mechanisms of dendritic cell-mediated immune tolerance have not yet been fully elucidated. Here, we report that there are two new subpopulations of CD4 + CD25 + FoxP3 + GITR + regulatory T cells (CD127 + 3G11 + and CD127 + 3G11 - cells). LPS-treated dendritic cells facilitate development of CD4 + CD127 + 3G11 - regulatory T cells but inhibit that of CD4 + CD127 + 3G11 + regulatory T cells. LPS-induced tolerogenic dendritic cells may cause immune tolerance through modulating balance of different subsets of CD4 + regulatory T cells mediated by CD127 and 3G11. Our results imply a new potential cellular mechanism of dendritic cell-mediated immune tolerance.

Graph Theory-Based Analysis of the Lymph Node Fibroblastic Reticular Cell Network.

PubMed

Novkovic, Mario; Onder, Lucas; Bocharov, Gennady; Ludewig, Burkhard

2017-01-01

Secondary lymphoid organs have developed segregated niches that are able to initiate and maintain effective immune responses. Such global organization requires tight control of diverse cellular components, specifically those that regulate lymphocyte trafficking. Fibroblastic reticular cells (FRCs) form a densely interconnected network in lymph nodes and provide key factors necessary for T cell migration and retention, and foster subsequent interactions between T cells and dendritic cells. Development of integrative systems biology approaches has made it possible to elucidate this multilevel complexity of the immune system. Here, we present a graph theory-based analysis of the FRC network in murine lymph nodes, where generation of the network topology is performed using high-resolution confocal microscopy and 3D reconstruction. This approach facilitates the analysis of physical cell-to-cell connectivity, and estimation of topological robustness and global behavior of the network when it is subjected to perturbation in silico.

Endocytic pathways downregulate the L1-type cell adhesion molecule neuroglian to promote dendrite pruning in Drosophila.

PubMed

Zhang, Heng; Wang, Yan; Wong, Jack Jing Lin; Lim, Kah-Leong; Liou, Yih-Cherng; Wang, Hongyan; Yu, Fengwei

2014-08-25

Pruning of unnecessary axons and/or dendrites is crucial for maturation of the nervous system. However, little is known about cell adhesion molecules (CAMs) that control neuronal pruning. In Drosophila, dendritic arborization neurons, ddaCs, selectively prune their larval dendrites. Here, we report that Rab5/ESCRT-mediated endocytic pathways are critical for dendrite pruning. Loss of Rab5 or ESCRT function leads to robust accumulation of the L1-type CAM Neuroglian (Nrg) on enlarged endosomes in ddaC neurons. Nrg is localized on endosomes in wild-type ddaC neurons and downregulated prior to dendrite pruning. Overexpression of Nrg alone is sufficient to inhibit dendrite pruning, whereas removal of Nrg causes precocious dendrite pruning. Epistasis experiments indicate that Rab5 and ESCRT restrain the inhibitory role of Nrg during dendrite pruning. Thus, this study demonstrates the cell-surface molecule that controls dendrite pruning and defines an important mechanism whereby sensory neurons, via endolysosomal pathway, downregulate the cell-surface molecule to trigger dendrite pruning. Copyright © 2014 Elsevier Inc. All rights reserved.

Vascular endothelial growth factor c/vascular endothelial growth factor receptor 3 signaling regulates chemokine gradients and lymphocyte migration from tissues to lymphatics.

PubMed

Iwami, Daiki; Brinkman, C Colin; Bromberg, Jonathan S

2015-04-01

Circulation of leukocytes via blood, tissue and lymph is integral to adaptive immunity. Afferent lymphatics form CCL21 gradients to guide dendritic cells and T cells to lymphatics and then to draining lymph nodes (dLN). Vascular endothelial growth factor C and vascular endothelial growth factor receptor 3 (VEGFR-3) are the major lymphatic growth factor and receptor. We hypothesized these molecules also regulate chemokine gradients and lymphatic migration. CD4 T cells were injected into the foot pad or ear pinnae, and migration to afferent lymphatics and dLN quantified by flow cytometry or whole mount immunohistochemistry. Vascular endothelial growth factor receptor 3 or its signaling or downstream actions were modified with blocking monoclonal antibodies (mAbs) or other reagents. Anti-VEGFR-3 prevented migration of CD4 T cells into lymphatic lumen and significantly decreased the number that migrated to dLN. Anti-VEGFR-3 abolished CCL21 gradients around lymphatics, although CCL21 production was not inhibited. Heparan sulfate (HS), critical to establish CCL21 gradients, was down-regulated around lymphatics by anti-VEGFR-3 and this was dependent on heparanase-mediated degradation. Moreover, a Phosphoinositide 3-kinase (PI3K)α inhibitor disrupted HS and CCL21 gradients, whereas a PI3K activator prevented the effects of anti-VEGFR-3. During contact hypersensitivity, VEGFR-3, CCL21, and HS expression were all attenuated, and anti-heparanase or PI3K activator reversed these effects. Vascular endothelial growth factor C/VEGFR-3 signaling through PI3Kα regulates the activity of heparanase, which modifies HS and CCL21 gradients around lymphatics. The functional and physical linkages of these molecules regulate lymphatic migration from tissues to dLN. These represent new therapeutic targets to influence immunity and inflammation.

Evaluation of Immune Responses Mediated by Listeria-Stimulated Human Dendritic Cells: Implications for Cancer Vaccine Therapy

DTIC Science & Technology

2014-07-01

and J.W. Young, Human dendritic cells : potent antigen-presenting cells at the crossroads of innate and adaptive immunity. J Immunol, 2005. 175(3): p...by Listeria-Stimulated Human Dendritic Cells : Implications for Cancer Vaccine Therapy PRINCIPAL INVESTIGATOR: David J. Chung, MD, PhD...5a. CONTRACT NUMBER Evaluation of Immune Responses Mediated by Listeria-Stimulated Human Dendritic Cells : Implications for Cancer Vaccine

Chlamydia trachomatis Cellular Exit Alters Interactions with Host Dendritic Cells

PubMed Central

Sherrid, Ashley M.

2017-01-01

ABSTRACT The strategies utilized by pathogens to exit host cells are an area of pathogenesis which has received surprisingly little attention, considering the necessity of this step for infections to propagate. Even less is known about how exit through these pathways affects downstream host-pathogen interactions and the generation of an immune response. Chlamydia trachomatis exits host epithelial cells through two equally active mechanisms: lysis and extrusion. Studies have characterized the outcome of interactions between host innate immune cells, such as dendritic cells and macrophages, and free, extracellular Chlamydia bacteria, such as those resulting from lysis. Exit via extrusion generates a distinct, host-membrane-bound compartment of Chlamydia separate from the original infected cell. In this study, we assessed the effect of containment within extrusions upon the interaction between Chlamydia and host dendritic cells. Extrusion dramatically affected the outcome of Chlamydia-dendritic cell interactions for both the bacterium and the host cell. Dendritic cells rapidly underwent apoptosis in response to engulfment of an extrusion, while uptake of an equivalent dose of free Chlamydia had no such effect. Containment within an extrusion also prolonged bacterial survival within dendritic cells and altered the initial innate immune signaling by the dendritic cell. PMID:28223346

Steroid Treatment Reduces Allergic Airway Inflammation and Does Not Alter the Increased Numbers of Dendritic Cells and Calcitonin Gene-Related Peptide-Expressing Neurons in Airway Sensory Ganglia.

PubMed

Le, Duc Dung; Funck, Ulrike; Wronski, Sabine; Heck, Sebastian; Tschernig, Thomas; Bischoff, Markus; Sester, Martina; Herr, Christian; Bals, Robert; Welte, Tobias; Braun, Armin; Dinh, Quoc Thai

2016-01-01

Our previous data demonstrated that allergic airway inflammation induces migration of dendritic cells (DC) into airway sensory jugular and nodose ganglia (jugular-nodose ganglion complex; JNC). Here we investigated the effects of steroid treatment regarding the expression and migration of DC and calcitonin gene-related peptide (CGRP)-immunoreactive neurons of vagal sensory ganglia during allergic airway inflammation. A house dust mite (HDM) model for allergic airway inflammation was used. The mice received 0.3 mg fluticasone propionate per kilogram of body weight in the last 9 days. JNC slices were analyzed on MHC II, the neuronal marker PGP9.5, and the neuropeptide CGRP. Allergic airway inflammation increased the numbers of DC and CGRP-expressing neurons in the JNC significantly in comparison to the controls (DC/neurons: HDM 44.58 ± 1.6% vs. saline 33.29 ± 1.6%, p < 0.05; CGRP-positive neurons/total neurons: HDM 30.65 ± 1.9% vs. saline 19.49 ± 2.3%, p < 0.05). Steroid treatment did not have any effect on the numbers of DC and CGRP-expressing neurons in the JNC compared to HDM-treated mice. The present findings indicate an important role of DC and CGRP-containing neurons in the pathogenesis of allergic airway inflammation. However, steroid treatment did not have an effect on the population of DC and neurons displaying CGRP in the JNC, whereas steroid treatment was found to suppress allergic airway inflammation. © 2015 S. Karger AG, Basel.

Immunological Characterization of Whole Tumour Lysate-Loaded Dendritic Cells for Cancer Immunotherapy

PubMed Central

Ottobrini, Luisa; Biasin, Mara; Borelli, Manuela; Lucignani, Giovanni; Trabattoni, Daria; Clerici, Mario

2016-01-01

Introduction Dendritic cells play a key role as initiators of T-cell responses, and even if tumour antigen-loaded dendritic cells can induce anti-tumour responses, their efficacy has been questioned, suggesting a need to enhance immunization strategies. Matherials & Methods We focused on the characterization of bone marrow-derived dendritic cells pulsed with whole tumour lysate (TAA-DC), as a source of known and unknown antigens, in a mouse model of breast cancer (MMTV-Ras). Dendritic cells were evaluated for antigen uptake and for the expression of MHC class I/II and costimulatory molecules and markers associated with maturation. Results Results showed that antigen-loaded dendritic cells are characterized by a phenotypically semi-mature/mature profile and by the upregulation of genes involved in antigen presentation and T-cell priming. Activated dendritic cells stimulated T-cell proliferation and induced the production of high concentrations of IL-12p70 and IFN-γ but only low levels of IL-10, indicating their ability to elicit a TH1-immune response. Furthermore, administration of Antigen loaded-Dendritic Cells in MMTV-Ras mice evoked a strong anti-tumour response in vivo as demonstrated by a general activation of immunocompetent cells and the release of TH1 cytokines. Conclusion Data herein could be useful in the design of antitumoral DC-based therapies, showing a specific activation of immune system against breast cancer. PMID:26795765

Pro-inflammatory Cytokine Expression of Spleen Dendritic Cells in Mouse Toxoplasmosis

PubMed Central

Nam, Ho-Woo; Ahn, Hye-Jin

2011-01-01

Dendritic cells have been known as a member of strong innate immune cells against infectious organelles. In this study, we evaluated the cytokine expression of splenic dendritic cells in chronic mouse toxoplasmosis by tissue cyst-forming Me49 strain and demonstrated the distribution of lymphoid dendritic cells by fluorescence-activated cell sorter (FACS). Pro-inflammatory cytokines, such as IL-1α, IL-1β, IL-6, and IL-10 increased rapidly at week 1 post-infection (PI) and peaked at week 3 PI. Serum IL-10 level followed the similar patterns. FACS analysis showed that the number of CD8α+/CD11c+ splenic dendritic cells increased at week 1 and peaked at week 3 PI. In conclusion, mouse splenic dendritic cells showed early and rapid cytokine changes and may have important protective roles in early phases of murine toxoplasmosis. PMID:21738265

Clonal type I interferon-producing and dendritic cell precursors are contained in both human lymphoid and myeloid progenitor populations.

PubMed

Chicha, Laurie; Jarrossay, David; Manz, Markus G

2004-12-06

Because of different cytokine responsiveness, surface receptor, and transcription factor expression, human CD11c(-) natural type I interferon-producing cells (IPCs) and CD11c(+) dendritic cells were thought to derive through lymphoid and myeloid hematopoietic developmental pathways, respectively. To directly test this hypothesis, we used an in vitro assay allowing simultaneous IPC, dendritic cell, and B cell development and we tested lymphoid and myeloid committed hematopoietic progenitor cells for their developmental capacity. Lymphoid and common myeloid and granulocyte/macrophage progenitors were capable of developing into both functional IPCs, expressing gene transcripts thought to be associated with lymphoid lineage development, and into dendritic cells. However, clonal progenitors for both populations were about fivefold more frequent within myeloid committed progenitor cells. Thus, in humans as in mice, natural IPC and dendritic cell development robustly segregates with myeloid differentiation. This would fit with natural interferon type I-producing cell and dendritic cell activity in innate immunity, the evolutionary older arm of the cellular immune system.

Dendritic Cells and Innate Immunity in Kidney Transplantation

PubMed Central

Zhuang, Quan; Lakkis, Fadi G.

2015-01-01

Summary This review summarizes emerging concepts related to the roles of dendritic cells and innate immunity in organ transplant rejection. First, it highlights the primary role that recipient, rather than donor, dendritic cells have in rejection and reviews their origin and function in the transplanted kidney. Second, it introduces the novel concept that recognition of allogeneic non-self by host monocytes (referred to here as innate allorecognition) is necessary for initiating rejection by inducing monocyte differentiation into mature, antigen-presenting dendritic cells. Both concepts provide opportunities for preventing rejection by targeting monocytes or dendritic cells. PMID:25629552

6-shogaol, an active constituent of dietary ginger, impairs cancer development and lung metastasis by inhibiting the secretion of CC-chemokine ligand 2 (CCL2) in tumor-associated dendritic cells.

PubMed

Hsu, Ya-Ling; Hung, Jen-Yu; Tsai, Ying-Ming; Tsai, Eing-Mei; Huang, Ming-Shyan; Hou, Ming-Feng; Kuo, Po-Lin

2015-02-18

This study has two novel findings: it is not only the first to demonstrate that tumor-associated dendritic cells (TADCs) facilitate lung and breast cancer metastasis in vitro and in vivo by secreting inflammatory mediator CC-chemokine ligand 2 (CCL2), but it is also the first to reveal that 6-shogaol can decrease cancer development and progression by inhibiting the production of TADC-derived CCL2. Human lung cancer A549 and breast cancer MDA-MB-231 cells increase TADCs to express high levels of CCL2, which increase cancer stem cell features, migration, and invasion, as well as immunosuppressive tumor-associated macrophage infiltration. 6-Shogaol decreases cancer-induced up-regulation of CCL2 in TADCs, preventing the enhancing effects of TADCs on tumorigenesis and metastatic properties in A549 and MDA-MB-231 cells. A549 and MDA-MB-231 cells enhance CCL2 expression by increasing the phosphorylation of signal transducer and activator of transcription 3 (STAT3), and the activation of STAT3 induced by A549 and MDA-MB-231 is completely inhibited by 6-shogaol. 6-Shogaol also decreases the metastasis of lung and breast cancers in mice. 6-Shogaol exerts significant anticancer effects on lung and breast cells in vitro and in vivo by targeting the CCL2 secreted by TADCs. Thus, 6-shogaol may have the potential of being an efficacious immunotherapeutic agent for cancers.

Cigarette smoke-induced accumulation of lung dendritic cells is interleukin-1α-dependent in mice

PubMed Central

2012-01-01

Background Evidence suggests that dendritic cells accumulate in the lungs of COPD patients and correlate with disease severity. We investigated the importance of IL-1R1 and its ligands IL-1α and β to dendritic cell accumulation and maturation in response to cigarette smoke exposure. Methods Mice were exposed to cigarette smoke using a whole body smoke exposure system. IL-1R1-, TLR4-, and IL-1α-deficient mice, as well as anti-IL-1α and anti-IL-1β blocking antibodies were used to study the importance of IL-1R1 and TLR4 to dendritic cell accumulation and activation. Results Acute and chronic cigarette smoke exposure led to increased frequency of lung dendritic cells. Accumulation and activation of dendritic cells was IL-1R1/IL-1α dependent, but TLR4- and IL-1β-independent. Corroborating the cellular data, expression of CCL20, a potent dendritic cells chemoattractant, was IL-1R1/IL-1α-dependent. Studies using IL-1R1 bone marrow-chimeric mice revealed the importance of IL-1R1 signaling on lung structural cells for CCL20 expression. Consistent with the importance of dendritic cells in T cell activation, we observed decreased CD4+ and CD8+ T cell activation in cigarette smoke-exposed IL-1R1-deficient mice. Conclusion Our findings convey the importance of IL-1R1/IL-1α to the recruitment and activation of dendritic cells in response to cigarette smoke exposure. PMID:22992200

Phase I (Safety) Study of Autologous Tolerogenic Dendritic Cells in Type 1 Diabetic Patients

PubMed Central

Giannoukakis, Nick; Phillips, Brett; Finegold, David; Harnaha, Jo; Trucco, Massimo

2011-01-01

OBJECTIVE The safety of dendritic cells to selectively suppress autoimmunity, especially in type 1 diabetes, has never been ascertained. We investigated the safety of autologous dendritic cells, stabilized into an immunosuppressive state, in established adult type 1 diabetic patients. RESEARCH DESIGN AND METHODS A randomized, double-blind, phase I study was conducted. A total of 10, otherwise generally healthy, insulin-requiring type 1 diabetic patients between 18 and 60 years of age, without any other known or suspected health conditions, received autologous dendritic cells, unmanipulated or engineered ex vivo toward an immunosuppressive state. Ten million cells were administered intradermally in the abdomen once every 2 weeks for a total of four administrations. The primary end point determined the proportion of patients with adverse events on the basis of the physician’s global assessment, hematology, biochemistry, and immune monitoring for a period of 12 months. RESULTS The dendritic cells were safely tolerated. There were no discernible adverse events in any patient throughout the study. Other than a significant increase in the frequency of peripheral B220+ CD11c− B cells, mainly seen in the recipients of engineered dendritic cells during the dendritic cell administration period, there were no statistically relevant differences in other immune populations or biochemical, hematological, and immune biomarkers compared with baseline. CONCLUSIONS Treatment with autologous dendritic cells, in a native state or directed ex vivo toward a tolerogenic immunosuppressive state, is safe and well tolerated. Dendritic cells upregulated the frequency of a potentially beneficial B220+ CD11c− B-cell population, at least in type 1 diabetes autoimmunity. PMID:21680720

WASp-dependent actin cytoskeleton stability at the dendritic cell immunological synapse is required for extensive, functional T cell contacts.

PubMed

Malinova, Dessislava; Fritzsche, Marco; Nowosad, Carla R; Armer, Hannah; Munro, Peter M G; Blundell, Michael P; Charras, Guillaume; Tolar, Pavel; Bouma, Gerben; Thrasher, Adrian J

2016-05-01

The immunological synapse is a highly structured and molecularly dynamic interface between communicating immune cells. Although the immunological synapse promotes T cell activation by dendritic cells, the specific organization of the immunological synapse on the dendritic cell side in response to T cell engagement is largely unknown. In this study, confocal and electron microscopy techniques were used to investigate the role of dendritic cell actin regulation in immunological synapse formation, stabilization, and function. In the dendritic cell-restricted absence of the Wiskott-Aldrich syndrome protein, an important regulator of the actin cytoskeleton in hematopoietic cells, the immunological synapse contact with T cells occupied a significantly reduced surface area. At a molecular level, the actin network localized to the immunological synapse exhibited reduced stability, in particular, of the actin-related protein-2/3-dependent, short-filament network. This was associated with decreased polarization of dendritic cell-associated ICAM-1 and MHC class II, which was partially dependent on Wiskott-Aldrich syndrome protein phosphorylation. With the use of supported planar lipid bilayers incorporating anti-ICAM-1 and anti-MHC class II antibodies, the dendritic cell actin cytoskeleton organized into recognizable synaptic structures but interestingly, formed Wiskott-Aldrich syndrome protein-dependent podosomes within this area. These findings demonstrate that intrinsic dendritic cell cytoskeletal remodeling is a key regulatory component of normal immunological synapse formation, likely through consolidation of adhesive interaction and modulation of immunological synapse stability. © The Author(s).

Dendritic cells in Barrett's esophagus and esophageal adenocarcinoma.

PubMed

Bobryshev, Yuri V; Tran, Dinh; Killingsworth, Murray C; Buckland, Michael; Lord, Reginald V N

2009-01-01

Like other premalignant conditions that develop in the presence of chronic inflammation, the development and progression of Barrett's esophagus is associated with the development of an immune response, but how this immune response is regulated is poorly understood. A comprehensive literature search failed to find any report of the presence of dendritic cells in Barrett's intestinal metaplasia and esophageal adenocarcinoma and this prompted our study. We used immunohistochemical staining and electron microscopy to examine whether dendritic cells are present in Barrett's esophagus and esophageal adenocarcinoma. Immunohistochemical staining with CD83, a specific marker for dendritic cells, was performed on paraffin-embedded sections of Barrett's intestinal metaplasia (IM, n = 12), dysplasia (n = 11) and adenocarcinoma (n = 14). CD83+ cells were identified in the lamina propria surrounding intestinal type glands in Barrett's IM, dysplasia, and cancer tissues. Computerized quantitative analysis showed that the numbers of dendritic cells were significantly higher in cancer tissues. Double immunostaining with CD83, CD20, and CD3, and electron microscopy demonstrated that dendritic cells are present in Barrett's esophagus and form clusters with T cells and B cells directly within the lamina propria. These findings demonstrate that dendritic cells are present in Barrett's tissues, with a significant increase in density in adenocarcinoma compared to benign Barrett's esophagus. Dendritic cells may have a role in the pathogenesis and immunotherapy treatment of Barrett's esophagus and adenocarcinoma.

Morphology, classification, and distribution of the projection neurons in the dorsal lateral geniculate nucleus of the rat.

PubMed

Ling, Changying; Hendrickson, Michael L; Kalil, Ronald E

2012-01-01

The morphology of confirmed projection neurons in the dorsal lateral geniculate nucleus (dLGN) of the rat was examined by filling these cells retrogradely with biotinylated dextran amine (BDA) injected into the visual cortex. BDA-labeled projection neurons varied widely in the shape and size of their cell somas, with mean cross-sectional areas ranging from 60-340 µm(2). Labeled projection neurons supported 7-55 dendrites that spanned up to 300 µm in length and formed dendritic arbors with cross-sectional areas of up to 7.0 × 10(4) µm(2). Primary dendrites emerged from cell somas in three broad patterns. In some dLGN projection neurons, primary dendrites arise from the cell soma at two poles spaced approximately 180° apart. In other projection neurons, dendrites emerge principally from one side of the cell soma, while in a third group of projection neurons primary dendrites emerge from the entire perimeter of the cell soma. Based on these three distinct patterns in the distribution of primary dendrites from cell somas, we have grouped dLGN projection neurons into three classes: bipolar cells, basket cells and radial cells, respectively. The appendages seen on dendrites also can be grouped into three classes according to differences in their structure. Short "tufted" appendages arise mainly from the distal branches of dendrites; "spine-like" appendages, fine stalks with ovoid heads, typically are seen along the middle segments of dendrites; and "grape-like" appendages, short stalks that terminate in a cluster of ovoid bulbs, appear most often along the proximal segments of secondary dendrites of neurons with medium or large cell somas. While morphologically diverse dLGN projection neurons are intermingled uniformly throughout the nucleus, the caudal pole of the dLGN contains more small projection neurons of all classes than the rostral pole.

Bortezomib as a new therapeutic approach for blastic plasmacytoid dendritic cell neoplasm

PubMed Central

Philippe, Laure; Ceroi, Adam; Bôle-Richard, Elodie; Jenvrin, Alizée; Biichle, Sabeha; Perrin, Sophie; Limat, Samuel; Bonnefoy, Francis; Deconinck, Eric; Saas, Philippe; Garnache-Ottou, Francine; Angelot-Delettre, Fanny

2017-01-01

Blastic plasmacytoid dendritic cell neoplasm is an aggressive hematologic malignancy with a poor prognosis. No consensus regarding optimal treatment modalities is currently available. Targeting the nuclear factor-kappa B pathway is considered a promising approach since blastic plasmacytoid dendritic cell neoplasm has been reported to exhibit constitutive activation of this pathway. Moreover, nuclear factor-kappa B inhibition in blastic plasmacytoid dendritic cell neoplasm cell lines, achieved using either an experimental specific inhibitor JSH23 or the clinical drug bortezomib, interferes in vitro with leukemic cell proliferation and survival. Here we extended these data by showing that primary blastic plasmacytoid dendritic cell neoplasm cells from seven patients were sensitive to bortezomib-induced cell death. We confirmed that bortezomib efficiently inhibits the phosphorylation of the RelA nuclear factor-kappa B subunit in blastic plasmacytoid dendritic cell neoplasm cell lines and primary cells from patients in vitro and in vivo in a mouse model. We then demonstrated that bortezomib can be associated with other drugs used in different chemotherapy regimens to improve its impact on leukemic cell death. Indeed, when primary blastic plasmacytoid dendritic cell neoplasm cells from a patient were grafted into mice, bortezomib treatment significantly increased the animals’ survival, and was associated with a significant decrease of circulating leukemic cells and RelA nuclear factor-kappa B subunit expression. Overall, our results provide a rationale for the use of bortezomib in combination with other chemotherapy for the treatment of patients with blastic plasmacytoid dendritic cell neoplasm. Based on our data, a prospective clinical trial combining proteasome inhibitor with classical drugs could be envisaged. PMID:28798071

Deletion of Wiskott–Aldrich syndrome protein triggers Rac2 activity and increased cross-presentation by dendritic cells

PubMed Central

Baptista, Marisa A. P.; Keszei, Marton; Oliveira, Mariana; Sunahara, Karen K. S.; Andersson, John; Dahlberg, Carin I. M.; Worth, Austen J.; Liedén, Agne; Kuo, I-Chun; Wallin, Robert P. A.; Snapper, Scott B.; Eidsmo, Liv; Scheynius, Annika; Karlsson, Mikael C. I.; Bouma, Gerben; Burns, Siobhan O.; Forsell, Mattias N. E.; Thrasher, Adrian J.; Nylén, Susanne; Westerberg, Lisa S.

2016-01-01

Wiskott–Aldrich syndrome (WAS) is caused by loss-of-function mutations in the WASp gene. Decreased cellular responses in WASp-deficient cells have been interpreted to mean that WASp directly regulates these responses in WASp-sufficient cells. Here, we identify an exception to this concept and show that WASp-deficient dendritic cells have increased activation of Rac2 that support cross-presentation to CD8+ T cells. Using two different skin pathology models, WASp-deficient mice show an accumulation of dendritic cells in the skin and increased expansion of IFNγ-producing CD8+ T cells in the draining lymph node and spleen. Specific deletion of WASp in dendritic cells leads to marked expansion of CD8+ T cells at the expense of CD4+ T cells. WASp-deficient dendritic cells induce increased cross-presentation to CD8+ T cells by activating Rac2 that maintains a near neutral pH of phagosomes. Our data reveals an intricate balance between activation of WASp and Rac2 signalling pathways in dendritic cells. PMID:27425374

Modelling IRF8 Deficient Human Hematopoiesis and Dendritic Cell Development with Engineered iPS Cells.

PubMed

Sontag, Stephanie; Förster, Malrun; Qin, Jie; Wanek, Paul; Mitzka, Saskia; Schüler, Herdit M; Koschmieder, Steffen; Rose-John, Stefan; Seré, Kristin; Zenke, Martin

2017-04-01

Human induced pluripotent stem (iPS) cells can differentiate into cells of all three germ layers, including hematopoietic stem cells and their progeny. Interferon regulatory factor 8 (IRF8) is a transcription factor, which acts in hematopoiesis as lineage determining factor for myeloid cells, including dendritic cells (DC). Autosomal recessive or dominant IRF8 mutations occurring in patients cause severe monocytic and DC immunodeficiency. To study IRF8 in human hematopoiesis we generated human IRF8-/- iPS cells and IRF8-/- embryonic stem (ES) cells using RNA guided CRISPR/Cas9n genome editing. Upon induction of hematopoietic differentiation, we demonstrate that IRF8 is dispensable for iPS cell and ES cell differentiation into hemogenic endothelium and for endothelial-to-hematopoietic transition, and thus development of hematopoietic progenitors. We differentiated iPS cell and ES cell derived progenitors into CD141+ cross-presenting cDC1 and CD1c+ classical cDC2 and CD303+ plasmacytoid DC (pDC). We found that IRF8 deficiency compromised cDC1 and pDC development, while cDC2 development was largely unaffected. Additionally, in an unrestricted differentiation regimen, IRF8-/- iPS cells and ES cells exhibited a clear bias toward granulocytes at the expense of monocytes. IRF8-/- DC showed reduced MHC class II expression and were impaired in cytokine responses, migration, and antigen presentation. Taken together, we engineered a human IRF8 knockout model that allows studying molecular mechanisms of human immunodeficiencies in vitro, including the pathophysiology of IRF8 deficient DC. Stem Cells 2017;35:898-908. © 2017 The Authors Stem Cells published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.

Hormonal Regulation of Dendritic Cell Differentiation in the Thymus.

PubMed

Shirshev, S V; Orlova, E G; Loginova, O A; Nekrasova, I V; Gorbunova, O L; Maslennikova, I L

2018-06-19

We studied the effect of hormones estriol, ghrelin, kisspeptin, and chorionic gonadotropin in concentrations corresponding to their content in the peripheral blood in each trimester of pregnancy on the expression of membrane molecules on myeloid and plasmacytoid dendritic cells of the thymus. It was found that thymic myeloid dendritic cells are sensitive to the action of estriol and kisspeptin. Estriol in a concentration of the first trimester of pregnancy reduces the number of myeloid dendritic cells expressing receptor for thymic stromal lymphopoietin (CD11c+TSLP-R + ) and inhibitory molecule B7-H3 (CD11c + CD276 + ). In contrast to estriol, kisspeptin regulates the processes of differentiation of thymic myeloid dendritic cells in concentrations typical of the second-third trimesters and reduced their total number (CD11c + ) and the number of cells expressing TSLP-R (CD11c + TSLP-R + ). Estriol and kisspeptin do not affect the total number of plasmacytoid dendritic cells (CD303 + ) and expression of TSLP-R and CD276 by these cells. Ghrelin and chorionic gonadotropin in the studied concentrations had no significant effect on the total number of thymic myeloid and plasmacytoid dendritic cells and on the expression of membrane molecules of TSLP-R and CD276.

Muscarinic regulation of Kenyon cell dendritic arborizations in adult worker honey bees

PubMed Central

Dobrin, Scott E.; Herlihy, J. Daniel; Robinson, Gene E.; Fahrbach, Susan E.

2011-01-01

The experience of foraging under natural conditions increases the volume of mushroom body neuropil in worker honey bees. A comparable increase in neuropil volume results from treatment of worker honey bees with pilocarpine, an agonist for muscarinic-type cholinergic receptors. A component of the neuropil growth induced by foraging experience is growth of dendrites in the collar region of the calyces. We show here, via analysis of Golgi-impregnated collar Kenyon cells with wedge arborizations, that significant increases in standard measures of dendritic complexity were also found in worker honey bees treated with pilocarpine. This result suggests that signaling via muscarinic-type receptors promotes the increase in Kenyon cell dendritic complexity associated with foraging. Treatment of worker honey bees with scopolamine, a muscarinic inhibitor, inhibited some aspects of dendritic growth. Spine density on the Kenyon cell dendrites varied with sampling location, with the distal portion of the dendritic field having greater total spine density than either the proximal or medial section. This observation may be functionally significant because of the stratified organization of projections from visual centers to the dendritic arborizations of the collar Kenyon cells. Pilocarpine treatment had no effect on the distribution of spines on dendrites of the collar Kenyon cells. PMID:21262388

"Subpial Fan Cell" - A Class of Calretinin Neuron in Layer 1 of Adult Monkey Prefrontal Cortex.

PubMed

Gabbott, Paul L A

2016-01-01

Layer 1 of the cortex contains populations of neurochemically distinct neurons and afferent fibers which markedly affect neural activity in the apical dendritic tufts of pyramidal cells. Understanding the causal mechanisms requires knowledge of the cellular architecture and synaptic organization of layer 1. This study has identified eight morphological classes of calretinin immunopositive (CRet+) neurons (including Cajal-Retzius cells) in layer 1 of the prefrontal cortex (PFC) in adult monkey (Macaca fasicularis), with a distinct class - termed "subpial fan (SPF) cell" - described in detail. SPF cells were rare horizontal unipolar CRet+ cells located directly beneath the pia with a single thick primary dendrite that branched into a characteristic fan-like dendritic tree tangential to the pial surface. Dendrites had spines, filamentous processes and thorny branchlets. SPF cells lay millimeters apart with intralaminar axons that ramified widely in upper layer 1. Such cells were GABA immunonegative (-) and occurred in areas beyond PFC. Interspersed amidst SPF cells displaying normal structural integrity were degenerating CRet+ neurons (including SPF cells) and clumps of lipofuscin-rich cellular debris. The number of degenerating SPF cells increased during adulthood. Ultrastructural analyses indicated SPF cell somata received asymmetric (A - presumed excitatory) and symmetric (S - presumed inhibitory) synaptic contacts. Proximal dendritic shafts received mainly S-type and distal shafts mostly A-type input. All dendritic thorns and most dendritic spines received both synapse types. The tangential areal density of SPF cell axonal varicosities varied radially from parent somata - with dense clusters in more distal zones. All boutons formed A-type contacts with CRet- structures. The main post-synaptic targets were dendritic shafts (67%; mostly spine-bearing) and dendritic spines (24%). SPF-SPF cell innervation was not observed. Morphometry of SPF cells indicated a unique class of CRet+/GABA- neuron in adult monkey PFC - possibly a subtype of persisting Cajal-Retzius cell. The distribution and connectivity of SPF cells suggest they act as integrative hubs in upper layer 1 during postnatal maturation. The main synaptic output of SPF cells likely provides a transminicolumnar excitatory influence across swathes of apical dendritic tufts - thus affecting information processing in discrete patches of layer 1 in adult monkey PFC.

Molecular and Electrophysiological Characterization of GABAergic Interneurons Expressing the Transcription Factor COUP-TFII in the Adult Human Temporal Cortex

PubMed Central

Varga, Csaba; Tamas, Gabor; Barzo, Pal; Olah, Szabolcs; Somogyi, Peter

2015-01-01

Transcription factors contribute to the differentiation of cortical neurons, orchestrate specific interneuronal circuits, and define synaptic relationships. We have investigated neurons expressing chicken ovalbumin upstream promoter transcription factor II (COUP-TFII), which plays a role in the migration of GABAergic neurons. Whole-cell, patch-clamp recording in vitro combined with colocalization of molecular cell markers in the adult cortex differentiates distinct interneurons. The majority of strongly COUP-TFII-expressing neurons were in layers I–III. Most calretinin (CR) and/or cholecystokinin- (CCK) and/or reelin-positive interneurons were also COUP-TFII-positive. CR-, CCK-, or reelin-positive neurons formed 80%, 20%, or 17% of COUP-TFII-positive interneurons, respectively. About half of COUP-TFII-/CCK-positive interneurons were CR-positive, a quarter of them reelin-positive, but none expressed both. Interneurons positive for COUP-TFII fired irregular, accommodating and adapting trains of action potentials (APs) and innervated mostly small dendritic shafts and rarely spines or somata. Paired recording showed that a calretinin-/COUP-TFII-positive interneuron elicited inhibitory postsynaptic potentials (IPSPs) in a reciprocally connected pyramidal cell. Calbindin, somatostatin, or parvalbumin-immunoreactive interneurons and most pyramidal cells express no immunohistochemically detectable COUP-TFII. In layers V and VI, some pyramidal cells expressed a low level of COUP-TFII in the nucleus. In conclusion, COUP-TFII is expressed in a diverse subset of GABAergic interneurons predominantly innervating small dendritic shafts originating from both interneurons and pyramidal cells. PMID:25787832

Therapeutic concentration of lithium stimulates complement C3 production in dendritic cells and microglia via GSK-3 inhibition.

PubMed

Yu, Zhiqian; Ono, Chiaki; Aiba, Setsuya; Kikuchi, Yoshie; Sora, Ichiro; Matsuoka, Hiroo; Tomita, Hiroaki

2015-02-01

Evidence indicates that widely prescribed mood stabilizer, lithium (Li), mediates cellular functions of differentiated monocytic cells, including microglial migration, monocyte-derived dendritic cell (MoDC) differentiation, and amelioration of monocytic malfunctions observed in neuropsychiatric diseases. Here, we surveyed molecules which take major roles in regulating these monocytic cellular functions. MoDCs treated with 1 and 5 mM Li, and microglia separated from Li-treated mice were subjected to microarray-based comprehensive gene expression analyses. Findings were validated using multiple experiments, including quantitative PCR, ELISA and immunostaining studies. Differing effects of Li on the two cell types were observed. Inflammation- and chemotaxis-relevant genes were significantly over-represented among Li-induced genes in MoDCs, whereas no specific category of genes was over-represented in microglia. The third component of complement (C3) was the only gene which was significantly induced by a therapeutic concentration of Li in both MoDCs and microglia. C3 production was increased by Li via GSK-3 inhibition. Li-induced C3 production was seen only in differentiated monocytic cells, but not in circulating monocytes. Our findings highlight a link between Li treatment and C3 production in differentiated monocytic cells, and reveal a regulatory role of GSK-3 in C3 production. Induction of microglial C3 production might be a novel neuroprotective mechanism of Li via regulating interactions between microglia and neurons. GLIA 2015;63:257-270. © 2014 Wiley Periodicals, Inc.

Clonal Type I Interferon–producing and Dendritic Cell Precursors Are Contained in Both Human Lymphoid and Myeloid Progenitor Populations

PubMed Central

Chicha, Laurie; Jarrossay, David; Manz, Markus G.

2004-01-01

Because of different cytokine responsiveness, surface receptor, and transcription factor expression, human CD11c− natural type I interferon–producing cells (IPCs) and CD11c+ dendritic cells were thought to derive through lymphoid and myeloid hematopoietic developmental pathways, respectively. To directly test this hypothesis, we used an in vitro assay allowing simultaneous IPC, dendritic cell, and B cell development and we tested lymphoid and myeloid committed hematopoietic progenitor cells for their developmental capacity. Lymphoid and common myeloid and granulocyte/macrophage progenitors were capable of developing into both functional IPCs, expressing gene transcripts thought to be associated with lymphoid lineage development, and into dendritic cells. However, clonal progenitors for both populations were about fivefold more frequent within myeloid committed progenitor cells. Thus, in humans as in mice, natural IPC and dendritic cell development robustly segregates with myeloid differentiation. This would fit with natural interferon type I–producing cell and dendritic cell activity in innate immunity, the evolutionary older arm of the cellular immune system. PMID:15557348

Immunotherapy with myeloid cells for tolerance induction

PubMed Central

Rodriguez-García, Mercedes; Boros, Peter; Bromberg, Jonathan S.; Ochando, Jordi C.

2013-01-01

Purpose of review Understanding the interplay between myeloid dendritic cells and T cells under tolerogenic conditions, and whether their interactions induce the development of antigen-specific regulatory T cells (Tregs) is critical to uncover the mechanisms involved in the induction of indefinite allograft survival. Recent findings Myeloid dendritic cell–T-cell interactions are seminal events that determine the outcome of the immune response, and multiple in-vitro protocols suggest the generation of tolerogenic myeloid dendritic cells that modulate T-cell responses, and determine the outcome of the immune response to an allograft following adoptive transfer. We believe that identifying specific conditions that lead to the generation of tolerogenic myeloid dendritic cells and Tregs are critical for the manipulation the immune response towards the development of transplantation tolerance. Summary We summarize recent findings regarding specific culture conditions that generate tolerogenic myeloid dendritic cells that induce T-cell hyporesponsiveness and Treg development, and represents a novel immunotherapeutic approach to promote the induction of indefinite graft survival prolongation. The interpretations presented here illustrate that different mechanisms govern the generation tolerogenic myeloid dendritic cells, and we discuss the concomitant therapeutic implications. PMID:20616727

TGF-β1-Induced Epithelial–Mesenchymal Transition Promotes Monocyte/Macrophage Properties in Breast Cancer Cells

PubMed Central

Johansson, Joel; Tabor, Vedrana; Wikell, Anna; Jalkanen, Sirpa; Fuxe, Jonas

2015-01-01

Breast cancer progression toward metastatic disease is linked to re-activation of epithelial–mesenchymal transition (EMT), a latent developmental process. Breast cancer cells undergoing EMT lose epithelial characteristics and gain the capacity to invade the surrounding tissue and migrate away from the primary tumor. However, less is known about the possible role of EMT in providing cancer cells with properties that allow them to traffic to distant sites. Given the fact that pro-metastatic cancer cells share a unique capacity with immune cells to traffic in-and-out of blood and lymphatic vessels we hypothesized that tumor cells undergoing EMT may acquire properties of immune cells. To study this, we performed gene-profiling analysis of mouse mammary EpRas tumor cells that had been allowed to adopt an EMT program after long-term treatment with TGF-β1 for 2 weeks. As expected, EMT cells acquired traits of mesenchymal cell differentiation and migration. However, in addition, we found another cluster of induced genes, which was specifically enriched in monocyte-derived macrophages, mast cells, and myeloid dendritic cells, but less in other types of immune cells. Further studies revealed that this monocyte/macrophage gene cluster was enriched in human breast cancer cell lines displaying an EMT or a Basal B profile, and in human breast tumors with EMT and undifferentiated (ER−/PR−) characteristics. The results identify an EMT-induced monocyte/macrophage gene cluster, which may play a role in breast cancer cell dissemination and metastasis. PMID:25674539

Suppression of zinc dendrites in zinc electrode power cells

NASA Technical Reports Server (NTRS)

Damjanovic, A.; Diggle, J. W.

1970-01-01

Addition of various tetraalkyl quarternary ammonium salts, to alkaline zincate electrolyte of cell, prevents formation of zinc dendrites during charging of zinc electrode. Electrode capacity is not impaired and elimination of dendrites prolongs cell life.

In vivo immunological antitumor effect of OK-432-stimulated dendritic cell transfer after radiofrequency ablation.

PubMed

Nakagawa, Hidetoshi; Mizukoshi, Eishiro; Iida, Noriho; Terashima, Takeshi; Kitahara, Masaaki; Marukawa, Yohei; Kitamura, Kazuya; Nakamoto, Yasunari; Hiroishi, Kazumasa; Imawari, Michio; Kaneko, Shuichi

2014-04-01

Radiofrequency ablation therapy (RFA) is a radical treatment for liver cancers and induces tumor antigen-specific immune responses. In the present study, we examined the antitumor effects of focal OK-432-stimulated dendritic cell (DC) transfer combined with RFA and analyzed the functional mechanisms involved using a murine model. C57BL/6 mice were injected subcutaneously with colon cancer cells (MC38) in their bilateral flanks. After the establishment of tumors, the subcutaneous tumor on one flank was treated using RFA, and then OK-432-stimulated DCs were injected locally. The antitumor effect of the treatment was evaluated by measuring the size of the tumor on the opposite flank, and the immunological responses were assessed using tumor-infiltrating lymphocytes, splenocytes and draining lymph nodes. Tumor growth was strongly inhibited in mice that exhibited efficient DC migration after RFA and OK-432-stimulated DC transfer, as compared to mice treated with RFA alone or treatment involving immature DC transfer. We also demonstrated that the antitumor effect of this treatment depended on both CD8-positive and CD4-positive cells. On the basis of our findings, we believe that combination therapy for metastatic liver cancer consisting of OK-432-stimulated DCs in combination with RFA can proceed to clinical trials, and it is anticipated to be markedly superior to RFA single therapy.

Characterization of Dendritic Cells Subpopulations in Skin and Afferent Lymph in the Swine Model

PubMed Central

Marquet, Florian; Bonneau, Michel; Pascale, Florentina; Urien, Celine; Kang, Chantal; Schwartz-Cornil, Isabelle; Bertho, Nicolas

2011-01-01

Transcutaneous delivery of vaccines to specific skin dendritic cells (DC) subsets is foreseen as a promising strategy to induce strong and specific types of immune responses such as tolerance, cytotoxicity or humoral immunity. Because of striking histological similarities between human and pig skin, pig is recognized as the most suitable model to study the cutaneous delivery of medicine. Therefore improving the knowledge on swine skin DC subsets would be highly valuable to the skin vaccine field. In this study, we showed that pig skin DC comprise the classical epidermal langerhans cells (LC) and dermal DC (DDC) that could be divided in 3 subsets according to their phenotypes: (1) the CD163neg/CD172aneg, (2) the CD163highCD172apos and (3) the CD163lowCD172apos DDC. These subtypes have the capacity to migrate from skin to lymph node since we detected them in pseudo-afferent lymph. Extensive phenotyping with a set of markers suggested that the CD163high DDC resemble the antibody response-inducing human skin DC/macrophages whereas the CD163negCD172low DDC share properties with the CD8+ T cell response-inducing murine skin CD103pos DC. This work, by showing similarities between human, mouse and swine skin DC, establishes pig as a model of choice for the development of transcutaneous immunisation strategies targeting DC. PMID:21298011

Indications for cellular migration from the central nervous system to its draining lymph nodes in CD11c-GFP+ bone-marrow chimeras following EAE.

PubMed

Schiefenhövel, Fridtjof; Immig, Kerstin; Prodinger, Carolin; Bechmann, Ingo

2017-07-01

The concept as to how the brain maintains its immune privilege has initially been based on observations that it is lacking classical lymph vessels and later, the absence of dendritic cells (DC). This view has been challenged by several groups demonstrating drainage/migration of injected tracers and cells into cervical lymph nodes (CLNs) and the presence of brain antigens in CLNs in the course of various brain pathologies. Using CD11c-diphtheria toxin receptor (DTR)-green fluorescent protein (GFP) transgenic (tg) mice, we have shown the existence of CD11c + cells, a main DC marker, within the brain parenchyma. Since injecting tracers or cells may cause barrier artefacts, we have now transplanted wild type (wt)-bone marrow (BM) to lethally irradiated CD11c-DTR-GFP tg mice to restrict the CD11c-DTR-GFP + population to the brain and induced experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). We observed ramified GFP + cells in the olfactory bulb, the cribriform plate, the nasal mucosa and superficial CLNs. We measured a significant increase of host gfp genomic DNA (gDNA) levels in lymph nodes (LNs) previously described as draining stations for the central nervous system (CNS). Using flow cytometry analysis, we observed an increase of the percentage of CD11c-GFP + cells in brain parenchyma in the course of EAE which is most likely due to an up-regulation of CD11c of resident microglial cells since levels of gfp gDNA did not increase. Our data supports the hypothesis that brain-resident antigen presenting cells (APC) are capable of migrating to CNS-draining LNs to present myelin-associated epitopes.

Bortezomib as a new therapeutic approach for blastic plasmacytoid dendritic cell neoplasm.

PubMed

Philippe, Laure; Ceroi, Adam; Bôle-Richard, Elodie; Jenvrin, Alizée; Biichle, Sabeha; Perrin, Sophie; Limat, Samuel; Bonnefoy, Francis; Deconinck, Eric; Saas, Philippe; Garnache-Ottou, Francine; Angelot-Delettre, Fanny

2017-11-01

Blastic plasmacytoid dendritic cell neoplasm is an aggressive hematologic malignancy with a poor prognosis. No consensus regarding optimal treatment modalities is currently available. Targeting the nuclear factor-kappa B pathway is considered a promising approach since blastic plasmacytoid dendritic cell neoplasm has been reported to exhibit constitutive activation of this pathway. Moreover, nuclear factor-kappa B inhibition in blastic plasmacytoid dendritic cell neoplasm cell lines, achieved using either an experimental specific inhibitor JSH23 or the clinical drug bortezomib, interferes in vitro with leukemic cell proliferation and survival. Here we extended these data by showing that primary blastic plasmacytoid dendritic cell neoplasm cells from seven patients were sensitive to bortezomib-induced cell death. We confirmed that bortezomib efficiently inhibits the phosphorylation of the RelA nuclear factor-kappa B subunit in blastic plasmacytoid dendritic cell neoplasm cell lines and primary cells from patients in vitro and in vivo in a mouse model. We then demonstrated that bortezomib can be associated with other drugs used in different chemotherapy regimens to improve its impact on leukemic cell death. Indeed, when primary blastic plasmacytoid dendritic cell neoplasm cells from a patient were grafted into mice, bortezomib treatment significantly increased the animals' survival, and was associated with a significant decrease of circulating leukemic cells and RelA nuclear factor-kappa B subunit expression. Overall, our results provide a rationale for the use of bortezomib in combination with other chemotherapy for the treatment of patients with blastic plasmacytoid dendritic cell neoplasm. Based on our data, a prospective clinical trial combining proteasome inhibitor with classical drugs could be envisaged. Copyright© Ferrata Storti Foundation.

Intravital live cell triggered imaging system reveals monocyte patrolling and macrophage migration in atherosclerotic arteries

NASA Astrophysics Data System (ADS)

McArdle, Sara; Chodaczek, Grzegorz; Ray, Nilanjan; Ley, Klaus

2015-02-01

Intravital multiphoton imaging of arteries is technically challenging because the artery expands with every heartbeat, causing severe motion artifacts. To study leukocyte activity in atherosclerosis, we developed the intravital live cell triggered imaging system (ILTIS). This system implements cardiac triggered acquisition as well as frame selection and image registration algorithms to produce stable movies of myeloid cell movement in atherosclerotic arteries in live mice. To minimize tissue damage, no mechanical stabilization is used and the artery is allowed to expand freely. ILTIS performs multicolor high frame-rate two-dimensional imaging and full-thickness three-dimensional imaging of beating arteries in live mice. The external carotid artery and its branches (superior thyroid and ascending pharyngeal arteries) were developed as a surgically accessible and reliable model of atherosclerosis. We use ILTIS to demonstrate Cx3cr1GFP monocytes patrolling the lumen of atherosclerotic arteries. Additionally, we developed a new reporter mouse (Apoe-/-Cx3cr1GFP/+Cd11cYFP) to image GFP+ and GFP+YFP+ macrophages "dancing on the spot" and YFP+ macrophages migrating within intimal plaque. ILTIS will be helpful to answer pertinent open questions in the field, including monocyte recruitment and transmigration, macrophage and dendritic cell activity, and motion of other immune cells.

Mannan-MUC1-pulsed dendritic cell immunotherapy: a phase I trial in patients with adenocarcinoma.

PubMed

Loveland, Bruce E; Zhao, Anne; White, Shane; Gan, Hui; Hamilton, Kate; Xing, Pei-Xiang; Pietersz, Geoffrey A; Apostolopoulos, Vasso; Vaughan, Hilary; Karanikas, Vaios; Kyriakou, Peter; McKenzie, Ian F C; Mitchell, Paul L R

2006-02-01

Tumor antigen-loaded dendritic cells show promise for cancer immunotherapy. This phase I study evaluated immunization with autologous dendritic cells pulsed with mannan-MUC1 fusion protein (MFP) to treat patients with advanced malignancy. Eligible patients had adenocarcinoma expressing MUC1, were of performance status 0 to 1, with no autoimmune disease. Patients underwent leukapheresis to generate dendritic cells by culture ex vivo with granulocyte macrophage colony-stimulating factor and interleukin 4 for 5 days. Dendritic cells were then pulsed overnight with MFP and harvested for reinjection. Patients underwent three cycles of leukapheresis and reinjection at monthly intervals. Patients with clinical benefit were able to continue with dendritic cell-MFP immunotherapy. Ten patients with a range of tumor types were enrolled, with median age of 60 years (range, 33-70 years); eight patients were of performance status 0 and two of performance status 1. Dendritic cell-MFP therapy led to strong T-cell IFNgamma Elispot responses to the vaccine and delayed-type hypersensitivity responses at injection sites in nine patients who completed treatments. Immune responses were sustained at 1 year in monitored patients. Antibody responses were seen in three patients only and were of low titer. Side effects were grade 1 only. Two patients with clearly progressive disease (ovarian and renal carcinoma) at entry were stable after initial therapy and went on to further leukapheresis and dendritic cell-MFP immunotherapy. These two patients have now each completed over 3 years of treatment. Immunization produced T-cell responses in all patients with evidence of tumor stabilization in 2 of the 10 advanced cancer patients treated. These data support further clinical evaluation of this dendritic cell-MFP immunotherapy.

Interaction of nNOS with PSD-95 negatively controls regenerative repair after stroke.

PubMed

Luo, Chun-Xia; Lin, Yu-Hui; Qian, Xiao-Dan; Tang, Ying; Zhou, Hai-Hui; Jin, Xing; Ni, Huan-Yu; Zhang, Feng-Yun; Qin, Cheng; Li, Fei; Zhang, Yu; Wu, Hai-Yin; Chang, Lei; Zhu, Dong-Ya

2014-10-01

Stroke is a major public health concern. The lack of effective therapies heightens the need for new therapeutic targets. Mammalian brain has the ability to rewire itself to restore lost functionalities. Promoting regenerative repair, including neurogenesis and dendritic remodeling, may offer a new therapeutic strategy for the treatment of stroke. Here, we report that interaction of neuronal nitric oxide synthase (nNOS) with the protein postsynaptic density-95 (PSD-95) negatively controls regenerative repair after stroke in rats. Dissociating nNOS-PSD-95 coupling in neurons promotes neuronal differentiation of neural stem cells (NSCs), facilitates the migration of newborn cells into the injured area, and enhances neurite growth of newborn neurons and dendritic spine formation of mature neurons in the ischemic brain of rats. More importantly, blocking nNOS-PSD-95 binding during the recovery stage improves stroke outcome via the promotion of regenerative repair in rats. Histone deacetylase 2 in NSCs may mediate the role of nNOS-PSD-95 association. Thus, nNOS-PSD-95 can serve as a target for regenerative repair after stroke. Copyright © 2014 the authors 0270-6474/14/3413535-14$15.00/0.

Automated Tracing of Horizontal Neuron Processes During Retinal Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kerekes, Ryan A; Martins, Rodrigo; Dyer, Michael A

2011-01-01

In the developing mammalian retina, horizontal neurons undergo a dramatic reorganization oftheir processes shortly after they migrate to their appropriate laminar position. This is an importantprocess because it is now understood that the apical processes are important for establishing theregular mosaic of horizontal cells in the retina and proper reorganization during lamination isrequired for synaptogenesis with photoreceptors and bipolar neurons. However, this process isdifficult to study because the analysis of horizontal neuron anatomy is labor intensive and time-consuming. In this paper, we present a computational method for automatically tracing the three-dimensional (3-D) dendritic structure of horizontal retinal neurons in two-photonmore » laser scanningmicroscope (TPLSM) imagery. Our method is based on 3-D skeletonization and is thus able topreserve the complex structure of the dendritic arbor of these cells. We demonstrate theeffectiveness of our approach by comparing our tracing results against two sets of semi-automatedtraces over a set of 10 horizontal neurons ranging in age from P1 to P5. We observe an averageagreement level of 81% between our automated trace and the manual traces. This automatedmethod will serve as an important starting point for further refinement and optimization.« less

Orchestration of transplantation tolerance by regulatory dendritic cell therapy or in-situ targeting of dendritic cells.

PubMed

Morelli, Adrian E; Thomson, Angus W

2014-08-01

Extensive research in murine transplant models over the past two decades has convincingly demonstrated the ability of regulatory dendritic cells (DCregs) to promote long-term allograft survival. We review important considerations regarding the source of therapeutic DCregs (donor or recipient) and their mode of action, in-situ targeting of DCregs, and optimal therapeutic regimens to promote DCreg function. Recent studies have defined protocols and mechanisms whereby ex-vivo-generated DCregs of donor or recipient origin subvert allogeneic T-cell responses and promote long-term organ transplant survival. Particular interest has focused on how donor antigen is acquired, processed and presented by autologous dendritic cells, on the stability of DCregs, and on in-situ targeting of dendritic cells to promote their tolerogenic function. New evidence of the therapeutic efficacy of DCregs in a clinically relevant nonhuman primate organ transplant model and production of clinical grade DCregs support early evaluation of DCreg therapy in human graft recipients. We discuss strategies currently used to promote dendritic cell tolerogenicity, including DCreg therapy and in-situ targeting of dendritic cells, with a view to improved understanding of underlying mechanisms and identification of the most promising strategies for therapeutic application.

Generation of dendritic cell-based vaccine using high hydrostatic pressure for non-small cell lung cancer immunotherapy

PubMed Central

Hradilova, Nada; Sadilkova, Lenka; Palata, Ondrej; Mysikova, Dagmar; Mrazkova, Hana; Lischke, Robert; Spisek, Radek; Adkins, Irena

2017-01-01

High hydrostatic pressure (HHP) induces immunogenic death of tumor cells which confer protective anti-tumor immunity in vivo. Moreover, DC pulsed with HHP-treated tumor cells induced therapeutic effect in mouse cancer model. In this study, we tested the immunogenicity, stability and T cell stimulatory activity of human monocyte-derived dendritic cell (DC)-based HHP lung cancer vaccine generated in GMP compliant serum free medium using HHP 250 MPa. DC pulsed with HHP-killed lung cancer cells and poly(I:C) enhanced DC maturation, chemotactic migration and production of pro-inflammatory cytokines after 24h. Moreover, DC-based HHP lung cancer vaccine showed functional plasticity after transfer into serum-containing media and stimulation with LPS or CD40L after additional 24h. LPS and CD40L stimulation further differentially enhanced the expression of costimulatory molecules and production of IL-12p70. DC-based HHP lung cancer vaccine decreased the number of CD4+CD25+Foxp3+ T regulatory cells and stimulated IFN-γ-producing tumor antigen-specific CD4+ and CD8+ T cells from non-small cell lung cancer (NSCLC) patients. Tumor antigen specific CD8+ and CD4+ T cell responses were detected in NSCLC patient’s against a selected tumor antigens expressed by lung cancer cell lines used for the vaccine generation. We also showed for the first time that protein antigen from HHP-killed lung cancer cells is processed and presented by DC to CD8+ T cells. Our results represent important preclinical data for ongoing NSCLC Phase I/II clinical trial using DC-based active cellular immunotherapy (DCVAC/LuCa) in combination with chemotherapy and immune enhancers. PMID:28187172

The Polarity Protein Partitioning-defective 1 (PAR-1) Regulates Dendritic Spine Morphogenesis through Phosphorylating Postsynaptic Density Protein 95 (PSD-95)*

PubMed Central

Wu, Qian; DiBona, Victoria L.; Bernard, Laura P.; Zhang, Huaye

2012-01-01

The polarity protein PAR-1 plays an essential role in many cellular contexts, including embryogenesis, asymmetric cell division, directional migration, and epithelial morphogenesis. Despite its known importance in different cellular processes, the role of PAR-1 in neuronal morphogenesis is less well understood. In particular, its role in the morphogenesis of dendritic spines, which are sites of excitatory synaptic inputs, has been unclear. Here, we show that PAR-1 is required for normal spine morphogenesis in hippocampal neurons. We further show that PAR-1 functions through phosphorylating the synaptic scaffolding protein PSD-95 in this process. Phosphorylation at a conserved serine residue in the KXGS motif in PSD-95 regulates spine morphogenesis, and a phosphomimetic mutant of this site can rescue the defects of kinase-dead PAR-1. Together, our findings uncover a role of PAR-1 in spine morphogenesis in hippocampal neurons through phosphorylating PSD-95. PMID:22807451

Identification of resident and inflammatory bone marrow derived cells in the sclera by bone marrow and haematopoietic stem cell transplantation

PubMed Central

Hisatomi, Toshio; Sonoda, Koh‐hei; Ishikawa, Fumihiko; Qiao, Hong; Nakamura, Takahiro; Fukata, Mitsuhiro; Nakazawa, Toru; Noda, Kousuke; Miyahara, Shinsuke; Harada, Mine; Kinoshita, Shigeru; Hafezi‐Moghadam, Ali; Ishibashi, Tatsuro; Miller, Joan W

2007-01-01

Aims To characterise bone marrow derived cells in the sclera under normal and inflammatory conditions, we examined their differentiation after transplantation from two different sources, bone marrow and haematopoietic stem cells (HSC). Methods Bone marrow and HSC from green fluorescent protein (GFP) transgenic mice were transplanted into irradiated wild‐type mice. At 1 month after transplantation, mice were sacrificed and their sclera examined by histology, immunohistochemistry (CD11b, CD11c, CD45), and transmission and scanning electron microscopy. To investigate bone marrow derived cell recruitment under inflammatory conditions, experimental autoimmune uveitis (EAU) was induced in transplanted mice. Results GFP positive cells were distributed in the entire sclera and comprised 22.4 (2.8)% (bone marrow) and 28.4 (10.9)% (HSC) of the total cells in the limbal zone and 18.1 (6.7)% (bone marrow) and 26.3 (3.4)% (HSC) in the peripapillary zone. Immunohistochemistry showed that GFP (+) CD11c (+), GFP (+) CD11b (+) cells migrated in the sclera after bone marrow and HSC transplantation. Transmission and scanning electron microscopy revealed antigen presenting cells among the scleral fibroblasts. In EAU mice, vast infiltration of GFP (+) cells developed into the sclera. Conclusion We have provided direct and novel evidence for the migration of bone marrow and HSC cells into the sclera differentiating into macrophages and dendritic cells. Vast infiltration of bone marrow and HSC cells was found to be part of the inflammatory process in EAU. PMID:17035278

Dendritic cell-associated immune inflammation of cardiac mucosa: a possible factor in the formation of Barrett's esophagus.

PubMed

Bobryshev, Yuri V; Tran, Dinh; Killingsworth, Murray C; Buckland, Michael; Lord, Reginald V N

2009-03-01

The development of Barrett's esophagus is poorly understood, but it has been suggested that cardiac mucosa is a precursor of intestinal type metaplasia and that inflammation of cardiac mucosa may play a role in the formation of Barrett's esophagus. The present study was undertaken to examine the presence and distribution of immune-inflammatory cells in cardiac mucosa, specifically focusing on dendritic cells because of their importance as regulators of immune reactions. Endoscopic biopsy specimens were obtained from 12 patients with cardiac mucosa without Barrett's esophagus or adenocarcinoma and from 21 patients with Barrett's esophagus without dysplasia (intestinal metaplasia). According to histology, in nine of the 21 specimens with Barrett's esophagus, areas of mucosa composed of cardiac type epithelium-lined glands were present as well. Immunohistochemical staining and electron microscopy were used to examine immune-inflammatory cells in paraffin-embedded sections. Immune-inflammatory cells, including T cells, B cells, dendritic cells, macrophages, and mast cells, were present in the connective tissue matrix that surrounded cardiac type epithelium-lined glands in all patients with cardiac mucosa. Clustering of dendritic cells with each other and with lymphocytes and the intrusion of dendritic cells between glandular mucus cells were observed. In the Barrett's esophagus specimens that contained cardiac type glands, computerized CD83 expression quantitation revealed that there were more dendritic cells in cardiac mucosa than in intestinal metaplasia. Immune-inflammatory infiltrates containing dendritic cells are consistently present in cardiac mucosa. The finding of a larger number of dendritic cells in areas of cardiac mucosa in Barrett's esophagus biopsies suggests that the immune inflammation of cardiac mucosa might play a role in modifying the local tissue environment to promote the development of specialized intestinal type metaplasia.

Evaluation of Immune Responses Mediated by Listeria-Stimulated Human Dendritic Cells: Implications for Cancer Vaccine Therapy

DTIC Science & Technology

2015-09-01

Award Number: W81XWH-11-1-0384 TITLE: Evaluation of Immune Responses Mediated by Listeria-Stimulated Human Dendritic Cells : Implications for...Immune Responses Mediated by Listeria-Stimulated Human Dendritic Cells : Implications for Cancer Vaccine Therapy 5b. GRANT NUMBER CA100463 5c...Listeria monocytogenes (Lm) on human dendritic cells (DCs) to optimize Lm-based DC cancer vaccines. The project aims are: 1) Compare the activation and

Dendritic Cells: A Spot on Sialic Acid

PubMed Central

Crespo, Hélio J.; Lau, Joseph T. Y.; Videira, Paula A.

2013-01-01

Glycans decorating cell surface and secreted proteins and lipids occupy the juncture where critical host–host and host-pathogen interactions occur. The role of glycan epitopes in cell–cell and cell-pathogen adhesive events is already well-established, and cell surface glycan structures change rapidly in response to stimulus and inflammatory cues. Despite the wide acceptance that glycans are centrally implicated in immunity, exactly how glycans and their changes contribute to the overall immune response remains poorly defined. Sialic acids are unique sugars that usually occupy the terminal position of the glycan chains and may be modified by external factors, such as pathogens, or upon specific physiological cellular events. At cell surface, sialic acid-modified structures form the key fundamental determinants for a number of receptors with known involvement in cellular adhesiveness and cell trafficking, such as the Selectins and the Siglec families of carbohydrate recognizing receptors. Dendritic cells (DCs) preside over the transition from innate to the adaptive immune repertoires, and no other cell has such relevant role in antigen screening, uptake, and its presentation to lymphocytes, ultimately triggering the adaptive immune response. Interestingly, sialic acid-modified structures are involved in all DC functions, such as antigen uptake, DC migration, and capacity to prime T cell responses. Sialic acid content changes along DC differentiation and activation and, while, not yet fully understood, these changes have important implications in DC functions. This review focuses on the developmental regulation of DC surface sialic acids and how manipulation of DC surface sialic acids can affect immune-critical DC functions by altering antigen endocytosis, pathogen and tumor cell recognition, cell recruitment, and capacity for T cell priming. The existing evidence points to a potential of DC surface sialylation as a therapeutic target to improve and diversify DC-based therapies. PMID:24409183

Dendritic cells induce specific cytotoxic T lymphocytes against prostate cancer TRAMP-C2 cells loaded with freeze- thaw antigen and PEP-3 peptide.

PubMed

Liu, Xiao-Qi; Jiang, Rong; Li, Si-Qi; Wang, Jing; Yi, Fa-Ping

2015-01-01

Prostate cancer is the most common cancer in men. In this study, we investigated immune responses of cytotoxic T lymphocytes (CTLs) against TRAMP-C2 prostate cancer cells after activation by dendritic cells (DCs) loaded with TRAMP-C2 freeze-thaw antigen and/or PEP-3 peptide in vitro. Bone marrow-derived DC from the bone marrow of the C57BL/6 were induced to mature by using the cytokine of rhGM-CSF and rhIL-4, and loaded with either the freeze-thaw antigen or PEP-3 peptide or both of them. Maturation of DCs was detected by flow cytometry. The killing efficiency of the CTLs on TRAMP-C2 cells were detected by flow cytometry, CCK8, colony formation, transwell migration, and wound-healing assay. The levels of the IFN-γ, TNF-β and IL-12 were measured by enzyme-linked immunosorbent assay (ELISA). Compared with the unloaded DCs, the loaded DCs had significantly increased expression of several phenotypes related to DC maturation. CTLs activated by DCs loaded with freeze-thaw antigen and PEP-3 peptide had more evident cytotoxicity against TRAMP-C2 cells in vitro. The secretion levels of IFN-γ, TNF-β and IL-12, secreted by DCs loaded with antigen and PEP-3 and interaction with T cells, were higher than in the other groups. Our results suggest that the CTLs activated by DCs loaded with TRAMP-C2 freeze-thaw antigen and PEP-3 peptide exert a remarkable killing efficiency against TRAMP-C2 cells in vitro.

Mapping of dendritic lesions in patients with herpes simplex keratitis using in vivo confocal microscopy

PubMed Central

Yokogawa, Hideaki; Kobayashi, Akira; Mori, Natsuko; Sugiyama, Kazuhisa

2015-01-01

Purpose To produce a two-dimensional reconstruction map of dendritic lesions in patients with herpes simplex keratitis (HSK) using in vivo confocal microscopy. Methods Four eyes of four patients (mean 65.8 years) with HSK presenting with a dendritic lesion were enrolled. Slit-lamp biomicroscopy and in vivo laser confocal microscopy were performed. Acquired confocal images at the level of the epithelium were arranged and mapped into subconfluent montages. Changes in the shape and degree of light reflection of abnormal cells and deposits around dendritic lesions as well as other corneal layers were qualitatively evaluated. Results Mapping of dendritic lesion was successful in all cases, and the subconfluent montages clearly showed the larger image of dendritic lesion. In all cases, the dendritic lesion consisted of hyperreflective irregular epithelial cells, and was surrounded by distorted and elongated epithelial cells. In three cases, hyperreflective deposits were noted at the midline of the lesion. The corneal stroma showed a hyperreflective honeycomb pattern. In two cases, inflammatory cells were observed at the level of endothelial cell layer. Conclusion Mapping of dendritic lesions in patients with HSK was successful in all patients using in vivo confocal microscopy. Cellular level observation of dendritic lesion at a relatively larger magnification may help understand the in vivo morphological change of HSK. Further study in more patients with HSK and nonherpetic dendritic lesion is needed to utilize confocal microscopy images in differential diagnosis and follow-up of the epithelial lesions with dendrite. PMID:26445524

Mapping of dendritic lesions in patients with herpes simplex keratitis using in vivo confocal microscopy.

PubMed

Yokogawa, Hideaki; Kobayashi, Akira; Mori, Natsuko; Sugiyama, Kazuhisa

2015-01-01

To produce a two-dimensional reconstruction map of dendritic lesions in patients with herpes simplex keratitis (HSK) using in vivo confocal microscopy. Four eyes of four patients (mean 65.8 years) with HSK presenting with a dendritic lesion were enrolled. Slit-lamp biomicroscopy and in vivo laser confocal microscopy were performed. Acquired confocal images at the level of the epithelium were arranged and mapped into subconfluent montages. Changes in the shape and degree of light reflection of abnormal cells and deposits around dendritic lesions as well as other corneal layers were qualitatively evaluated. Mapping of dendritic lesion was successful in all cases, and the subconfluent montages clearly showed the larger image of dendritic lesion. In all cases, the dendritic lesion consisted of hyperreflective irregular epithelial cells, and was surrounded by distorted and elongated epithelial cells. In three cases, hyperreflective deposits were noted at the midline of the lesion. The corneal stroma showed a hyperreflective honeycomb pattern. In two cases, inflammatory cells were observed at the level of endothelial cell layer. Mapping of dendritic lesions in patients with HSK was successful in all patients using in vivo confocal microscopy. Cellular level observation of dendritic lesion at a relatively larger magnification may help understand the in vivo morphological change of HSK. Further study in more patients with HSK and nonherpetic dendritic lesion is needed to utilize confocal microscopy images in differential diagnosis and follow-up of the epithelial lesions with dendrite.

Evaluation of accessory cell heterogeneity. III. Role of dendritic cells in the in vitro activation of the antibody response to soluble antigens.

PubMed

Erb, P; Ramila, G; Sklenar, I; Kennedy, M; Sunshine, G H

1985-05-01

Dendritic cells and macrophages obtained from spleen and peritoneal exudate were tested as accessory cells for the activation of lymphokine production by T cells, for supporting T-B cooperation and for the induction of antigen-specific T helper cells. Dendritic cells as well as macrophages were able to activate T cells for interleukin-2 secretion and functioned as accessory cells in T-B cooperation, but only macrophages induced T helper cells, which cooperate with B cells by a linked recognition interaction, to soluble antigens. Dendritic cell- and antigen-activated T cells also did not help B cells in the presence of Con A supernatants which contained various T cell- and B cell-stimulatory factors. The failure of dendritic cells to differentiate memory into functional T helper cells, but their efficient accessory cell function in T-B cooperation, where functional T helper cells are already present, can be best explained by a differential accessory cell requirement for T helper cell activation dependent on the differentiation stage of the T helper cell.

Stabilized Lithium-Metal Surface in a Polysulfide-Rich Environment of Lithium-Sulfur Batteries.

PubMed

Zu, Chenxi; Manthiram, Arumugam

2014-08-07

Lithium-metal anode degradation is one of the major challenges of lithium-sulfur (Li-S) batteries, hindering their practical utility as next-generation rechargeable battery chemistry. The polysulfide migration and shuttling associated with Li-S batteries can induce heterogeneities of the lithium-metal surface because it causes passivation by bulk insulating Li2S particles/electrolyte decomposition products on a lithium-metal surface. This promotes lithium dendrite formation and leads to poor lithium cycling efficiency with complicated lithium surface chemistry. Here, we show copper acetate as a surface stabilizer for lithium metal in a polysulfide-rich environment of Li-S batteries. The lithium surface is protected from parasitic reactions with the organic electrolyte and the migrating polysulfides by an in situ chemical formation of a passivation film consisting of mainly Li2S/Li2S2/CuS/Cu2S and electrolyte decomposition products. This passivation film also suppresses lithium dendrite formation by controlling the lithium deposition sites, leading to a stabilized lithium surface characterized by a dendrite-free morphology and improved surface chemistry.

Functional properties of granule cells with hilar basal dendrites in the epileptic dentate gyrus.

PubMed

Kelly, Tony; Beck, Heinz

2017-01-01

The maturation of adult-born granule cells and their functional integration into the network is thought to play a key role in the proper functioning of the dentate gyrus. In temporal lobe epilepsy, adult-born granule cells in the dentate gyrus develop abnormally and possess a hilar basal dendrite (HBD). Although morphological studies have shown that these HBDs have synapses, little is known about the functional properties of these HBDs or the intrinsic and network properties of the granule cells that possess these aberrant dendrites. We performed patch-clamp recordings of granule cells within the granule cell layer "normotopic" from sham-control and status epilepticus (SE) animals. Normotopic granule cells from SE animals possessed an HBD (SE + HBD + cells) or not (SE + HBD - cells). Apical and basal dendrites were stimulated using multiphoton uncaging of glutamate. Two-photon Ca 2+ imaging was used to measure Ca 2+ transients associated with back-propagating action potentials (bAPs). Near-synchronous synaptic input integrated linearly in apical dendrites from sham-control animals and was not significantly different in apical dendrites of SE + HBD - cells. The majority of HBDs integrated input linearly, similar to apical dendrites. However, 2 of 11 HBDs were capable of supralinear integration mediated by a dendritic spike. Furthermore, the bAP-evoked Ca 2+ transients were relatively well maintained along HBDs, compared with apical dendrites. This further suggests an enhanced electrogenesis in HBDs. In addition, the output of granule cells from epileptic tissue was enhanced, with both SE + HBD - and SE + HBD + cells displaying increased high-frequency (>100 Hz) burst-firing. Finally, both SE + HBD - and SE + HBD + cells received recurrent excitatory input that was capable of generating APs, especially in the absence of feedback inhibition. Taken together, these data suggest that the enhanced excitability of HBDs combined with the altered intrinsic and network properties of granule cells collude to promote excitability and synchrony in the epileptic dentate gyrus. Wiley Periodicals, Inc. © 2016 International League Against Epilepsy.

Structural basis of orientation sensitivity of cat retinal ganglion cells.

PubMed

Leventhal, A G; Schall, J D

1983-11-10

We investigated the structural basis of the physiological orientation sensitivity of retinal ganglion cells (Levick and Thibos, '82). The dendritic fields of 840 retinal ganglion cells labeled by injections of horseradish peroxidase into the dorsal lateral geniculate nucleus (LGNd) or optic tracts of normal cats. Siamese cats, and cat deprived of patterned visual experience from birth by monocular lid-suture (MD) were studied. Mathematical techniques designed to analyze direction were used to find the dendritic field orientation of each cell. Statistical techniques designed for angular data were used to determine the relationship between dendritic field orientation and angular position on the retina (polar angle). Our results indicate that 88% of retinal ganglion cells have oriented dendritic fields and that dendritic field orientation is related systematically to retinal position. In all regions of retina more that 0.5 mm from the area centralis the dendritic fields of retinal ganglion cells are oriented radially, i.e., like the spokes of a wheel having the area centralis at its hub. This relationship was present in all animals and cell types studied and was strongest for cells located close to the horizontal meridian (visual streak) of the retina. Retinal ganglion cells appear to be sensitive to stimulus orientation because they have oriented dendritic fields.

Manipulation of visible-light polarization with dendritic cell-cluster metasurfaces.

PubMed

Fang, Zhen-Hua; Chen, Huan; An, Di; Luo, Chun-Rong; Zhao, Xiao-Peng

2018-06-26

Cross-polarization conversion plays an important role in visible light manipulation. Metasurface with asymmetric structure can be used to achieve polarization conversion of linearly polarized light. Based on this, we design a quasi-periodic dendritic metasurface model composed of asymmetric dendritic cells. The simulation indicates that the asymmetric dendritic structure can vertically rotate the polarization direction of the linear polarization wave in visible light. Silver dendritic cell-cluster metasurface samples were prepared by the bottom-up electrochemical deposition. It experimentally proved that they could realize the cross - polarization conversion in visible light. Cross-polarized propagating light is deflected into anomalous refraction channels. Dendritic cell-cluster metasurface with asymmetric quasi-periodic structure conveys significance in cross-polarization conversion research and features extensive practical application prospect and development potential.

Wnt5 and Drl/Ryk Gradients Pattern the Drosophila Olfactory Dendritic Map

PubMed Central

Wu, Yuping; Helt, Jay-Christian; Wexler, Emily; Petrova, Iveta M.; Noordermeer, Jasprina N.; Fradkin, Lee G.

2014-01-01

During development, dendrites migrate to their correct locations in response to environmental cues. The mechanisms of dendritic guidance are poorly understood. Recent work has shown that the Drosophila olfactory map is initially formed by the spatial segregation of the projection neuron (PN) dendrites in the developing antennal lobe (AL). We report here that between 16 and 30 h after puparium formation, the PN dendrites undergo dramatic rotational reordering to achieve their final glomerular positions. During this period, a novel set of AL-extrinsic neurons express high levels of the Wnt5 protein and are tightly associated with the dorsolateral edge of the AL. Wnt5 forms a dorsolateral-high to ventromedial-low pattern in the antennal lobe neuropil. Loss of Wnt5 prevents the ventral targeting of the dendrites, whereas Wnt5 overexpression disrupts dendritic patterning. We find that Drl/Ryk, a known Wnt5 receptor, is expressed in a dorsolateral-to-ventromedial (DL > VM) gradient by the PN dendrites. Loss of Drl in the PNs results in the aberrant ventromedial targeting of the dendrites, a defect that is suppressed by reduction in Wnt5 gene dosage. Conversely, overexpression of Drl in the PNs results in the dorsolateral targeting of their dendrites, an effect that requires Drl's cytoplasmic domain. We propose that Wnt5 acts as a repulsive guidance cue for the PN dendrites, whereas Drl signaling in the dendrites inhibits Wnt5 signaling. In this way, the precise expression patterns of Wnt5 and Drl orient the PN dendrites allowing them to target their final glomerular positions. PMID:25378162

Myeloid dendritic cells frequencies are increased in children with autism spectrum disorder and associated with amygdala volume and repetitive behaviors

PubMed Central

Breece, Elizabeth; Paciotti, Brian; Nordahl, Christine Wu; Ozonoff, Sally; Van de Water, Judy A.; Rogers, Sally J.; Amaral, David; Ashwood, Paul

2012-01-01

The pathophysiology of Autism Spectrum Disorder (ASD) is not yet known; however, studies suggest that dysfunction of the immune system affects many children with ASD. Increasing evidence points to dysfunction of the innate immune system including activation of microglia and perivascular macrophages, increases in inflammatory cytokines/chemokines in brain tissue and CSF, and abnormal peripheral monocyte cell function. Dendritic cells are major players in innate immunity and have important functions in the phagocytosis of pathogens or debris, antigen presentation, activation of naïve T cells, induction of tolerance and cytokine/chemokine production. In this study, we assessed circulating frequencies of myeloid dendritic cells (defined as Lin-1−BDCA1+CD11c+ and Lin-1−BDCA3+CD123−) and plasmacytoid dendritic cells (Lin-1− BDCA2+CD123+ or Lin-1−BDCA4+ CD11c−) in 57 children with ASD, and 29 typically developing controls of the same age, all of who were enrolled as part of the Autism Phenome Project (APP). The frequencies of dendritic cells and associations with behavioral assessment and MRI measurements of amygdala volume were compared in the same participants. The frequencies of myeloid dendritic cells were significantly increased in children with ASD compared to typically developing controls (p < 0.03). Elevated frequencies of myeloid dendritic cells were positively associated with abnormal right and left amygdala enlargement, severity of gastrointestinal symptoms and increased repetitive behaviors. The frequencies of plasmacytoid dendritic cells were also associated with amygdala volumes as well as developmental regression in children with ASD. Dendritic cells play key roles in modulating immune responses and differences in frequencies or functions of these cells may result in immune dysfunction in children with ASD. These data further implicate innate immune cells in the complex pathophysiology of ASD. PMID:23063420

OK-432 synergizes with IFN-γ to confer dendritic cells with enhanced antitumor immunity.

PubMed

Pan, Ke; Lv, Lin; Zheng, Hai-xia; Zhao, Jing-jing; Pan, Qiu-zhong; Li, Jian-jun; Weng, De-sheng; Wang, Dan-dan; Jiang, Shan-shan; Chang, Alfred E; Li, Qiao; Xia, Jian-chuan

2014-03-01

Generation of functional dendritic cells (DCs) with boosted immunity after the withdrawal of initial activation/maturation conditions remains a significant challenge. In this study, we investigated the impact of a newly developed maturation cocktail consisting of OK-432 and interferon-gamma (IFN-γ) on the function of human monocyte-derived DCs (MoDCs). We found that OK-432 plus IFN-γ stimulation could induce significantly stronger expression of surface molecules, production of cytokines, as well as migration of DCs compared with OK-432 stimulation alone. Most importantly, DCs matured with OK-432 plus IFN-γ-induced maintained secretion of interleukin-12 (IL-12)p70 in secondary culture after stimulus withdrawal. Functionally, OK-432 plus IFN-γ-conditioned DCs induce remarkable Th1 and Tc1 responses more effectively than OK-432 alone, even more than the use of α-type-1 cytokine cocktail. As a result, DCs matured with OK-432 plus IFN-γ can prime stronger cytotoxic lymphocyte (CTL) and natural killer (NK) cell response against tumor cells in vitro. Peripheral blood mononuclear cells activated by DCs matured with OK-432 plus IFN-γ also showed greater tumor growth inhibition in vivo in null mice. Molecular mechanistic analysis showed that DC maturation using IFN-γ in concert with OK-432 involves the activation of p38 and nuclear factor-kappa B (NF-κB) pathways. This study provided a novel strategy to generate more potent immune segments in DC vaccine.

Liposomes-coated gold nanocages with antigens and adjuvants targeted delivery to dendritic cells for enhancing antitumor immune response.

PubMed

Liang, Ruijing; Xie, Jun; Li, Jun; Wang, Ke; Liu, Liping; Gao, Yujie; Hussain, Mubashir; Shen, Guanxin; Zhu, Jintao; Tao, Juan

2017-12-01

For nanovaccine-based cancer immunotherapy, dendritic cells (DCs) are one of the most powerful antigen presenting cells (APCs) that initiate and promote the maturation of antigen-specific cytotoxic T lymphocytes (e.g., CD8 + T cells) to induce the local and systemic antitumor immunity and further suppress the tumor metastasis and produce long-term protection against tumor. Thus, the activation and maturation of DCs is the prerequisite for efficient CD8 + T cell-based antitumor immune responses, which is considered as a primary and promising task for nanovaccine engineering. Herein, we introduce a versatile nanovaccine of liposomes-coated gold nanocages (Lipos-AuNCs) modified with DCs specific antibody aCD11c for targeted delivery of adjuvant MPLA and melanoma antigen peptide TRP2 to promote the activation and maturation of DCs, and enhance tumor specific T lymphocytes responses. Moreover, AuNCs accumulation and AuNCs-engulfed DCs migration to regional lymph nodes (RLNs) became real-time visualization through in vivo fluorescence and photoacoustic (PA) imaging to monitor the immunity process. In vivo experimental results demonstrated that the targeted antigen/adjuvants-loaded AuNCs exhibited enhanced antitumor immune response to inhibit tumor growth and metastasis in both B16-F10 prophylactic and lung metastasis models, which may act as a promising nanoplatform for antitumor immunotherapy and in vivo tracking. Copyright © 2017 Elsevier Ltd. All rights reserved.

Golgi, electron-microscopic and combined Golgi-electron-microscopic studies of the mitral cells in the goldfish olfactory bulb.

PubMed

Oka, Y

1983-04-01

The local neuronal circuitry of goldfish olfactory bulb was analyzed in Golgi preparations combining light- and electron-microscopy, as well as in routinely prepared ultrastructural preparations. Mitral cells were identified with the light-microscope in Golgi-impregnated thick sections according to the following criteria: (1) cell bodies were distributed irregularly in a wide layer between 100 and 200 micrometer from the surface, (2) cell bodies were larger than other neurons (10-20 micrometer in diameter), and (3) the dendrites were directed toward the superficially-located olfactory nerve layer where they ended as highly branched glomerular tufts. These impregnated cells were examined by electron-microscopy in serial section. The results demonstrate synaptic organization in relation to the mitral cells. (1) Glomerular tufts received afferent input from primary olfactory axons which made Gray's Type I synaptic contacts. These dendrites also had reciprocal dendrodendritic synapses with dendrites of certain non-mitral cells. (2) Dendritic shafts of mitral cells made reciprocal dendritic synapses with dendrites of certain non-mitral cells. (3) Cell bodies and their initial axon segments had reciprocal synapses with certain dendrites but occurred infrequently. In reciprocal synapses, the direction of the Gray Type I (asymmetrical) is away from the mitral cell while those with Gray Type II synapses (symmetrical) are toward the mitral cell. Assuming that the type I synapse is excitatory and Type II is inhibitory, these findings explain the electrophysiological demonstration of self-inhibition discharge found in mitral cells.

Linking macroscopic with microscopic neuroanatomy using synthetic neuronal populations.

PubMed

Schneider, Calvin J; Cuntz, Hermann; Soltesz, Ivan

2014-10-01

Dendritic morphology has been shown to have a dramatic impact on neuronal function. However, population features such as the inherent variability in dendritic morphology between cells belonging to the same neuronal type are often overlooked when studying computation in neural networks. While detailed models for morphology and electrophysiology exist for many types of single neurons, the role of detailed single cell morphology in the population has not been studied quantitatively or computationally. Here we use the structural context of the neural tissue in which dendritic trees exist to drive their generation in silico. We synthesize the entire population of dentate gyrus granule cells, the most numerous cell type in the hippocampus, by growing their dendritic trees within their characteristic dendritic fields bounded by the realistic structural context of (1) the granule cell layer that contains all somata and (2) the molecular layer that contains the dendritic forest. This process enables branching statistics to be linked to larger scale neuroanatomical features. We find large differences in dendritic total length and individual path length measures as a function of location in the dentate gyrus and of somatic depth in the granule cell layer. We also predict the number of unique granule cell dendrites invading a given volume in the molecular layer. This work enables the complete population-level study of morphological properties and provides a framework to develop complex and realistic neural network models.

Linking Macroscopic with Microscopic Neuroanatomy Using Synthetic Neuronal Populations

PubMed Central

Schneider, Calvin J.; Cuntz, Hermann; Soltesz, Ivan

2014-01-01

Dendritic morphology has been shown to have a dramatic impact on neuronal function. However, population features such as the inherent variability in dendritic morphology between cells belonging to the same neuronal type are often overlooked when studying computation in neural networks. While detailed models for morphology and electrophysiology exist for many types of single neurons, the role of detailed single cell morphology in the population has not been studied quantitatively or computationally. Here we use the structural context of the neural tissue in which dendritic trees exist to drive their generation in silico. We synthesize the entire population of dentate gyrus granule cells, the most numerous cell type in the hippocampus, by growing their dendritic trees within their characteristic dendritic fields bounded by the realistic structural context of (1) the granule cell layer that contains all somata and (2) the molecular layer that contains the dendritic forest. This process enables branching statistics to be linked to larger scale neuroanatomical features. We find large differences in dendritic total length and individual path length measures as a function of location in the dentate gyrus and of somatic depth in the granule cell layer. We also predict the number of unique granule cell dendrites invading a given volume in the molecular layer. This work enables the complete population-level study of morphological properties and provides a framework to develop complex and realistic neural network models. PMID:25340814

Technique for obtaining highly enriched, quiescent immature Langerhans cells suitable for ex vivo assays.

PubMed

Tchou, Isabelle; Sabido, Odile; Lambert, Claude; Misery, Laurent; Garraud, Olivier; Genin, Christian

2003-03-03

Epidermis and surface epithelium-dendritic cells comprise of immature cells termed Langerhans cells (LCs), which express characteristically the Birbeck granules, along with surface markers such as CD1a. These cells can capture a pathogen and then migrate and differentiate to a more mature stage. During this maturation process, dentritic cells express surface markers differentially. In physio-pathological models of infection where LCs are involved, it is critically important to ensure that the LCs tested in vitro are still immature and are not artefactually matured-dentritic cells. For experimental purposes, LCs were isolated from skin epidermis obtained from patients undergoing plastic surgery. This work thus aimed at collecting fresh LCs ex vivo and at testing the cells for phenotypic and functional characteristics of the immature stage. After mechanic disruption of the epidermis and proceeding for single cell suspension obtaining, two methods for purification were tested in parallel: (a) a positive immuno-magnetic separation by anti-CD1a-coated beads and (b) a purely mechanic purification system based on a three-step Ficoll floatation process. Both systems were equally efficient in terms of purification and yield. By using flow cytometry phenotyping, we have demonstrated that the use of magnetic beads led to some degree of maturation of CD1a(+) LCs, contrary to the repeated Ficoll floatation. This work calls attention for the use of certain monoclonal antibodies such as anti-CD1a to purify immature dendritic cells as they pre-activate these cells. Pre-activation would render a number of assays on the early events of LC physiology invalid, contrary to the purification of fresh skin epidermis LCs by means of a repeated Ficoll floatation.

Metastatic Melanoma Secreted IL-10 Down-Regulates CD1 Molecules on Dendritic Cells in Metastatic Tumor Lesions

PubMed Central

Gerlini, Gianni; Tun-Kyi, Adrian; Dudli, Christa; Burg, Günter; Pimpinelli, Nicola; Nestle, Frank O.

2004-01-01

CD1 molecules are expressed by antigen-presenting cells such as dendritic cells and mediate primary immune responses to lipids and glycolipids which have been shown to be expressed by various tumors. Glycolipids are expressed by melanoma cells but, despite their immunogenicity, no efficient spontaneous immune responses are elicited. As IL-10 has previously been shown to down-regulate CD1a on dendritic cells and is known to be expressed by various melanoma cell lines, we investigated if melanoma-derived IL-10 could down-regulate CD1 molecule expression on dendritic cells as a possible way to circumvent immune recognition. We found that CD1a, CD1b, CD1c, and CD1d were significantly down-regulated on dendritic cells in metastatic (n = 10) but not in primary melanoma lesions (n = 10). We further detected significantly higher IL-10 protein levels in metastatic than in primary melanomas. Moreover, supernatants from metastatic melanomas were significantly more effective in down-regulating CD1 molecules on dendritic cells than supernatants from primary melanoma cultures. This effect was blocked using a neutralizing IL-10 antibody in a dose dependent manner. Our findings suggest that metastatic but not primary melanomas can down-regulate CD1 molecules on infiltrating dendritic cells by secreting IL-10 which may represent a novel way to escape the immune response directed against the tumor. PMID:15579430

Sphingosine-1-phosphate receptor-1 (S1P1) is expressed by lymphocytes, dendritic cells, and endothelium and modulated during inflammatory bowel disease

PubMed Central

Karuppuchamy, Thangaraj; Behrens, En-hui; González-Cabrera, Pedro; Sarkisyan, Gor; Gima, Lauren; Boyer, Joshua D.; Bamias, Giorgos; Jedlicka, Paul; Veny, Marisol; Clark, David; Peach, Robert; Scott, Fiona; Rosen, Hugh; Rivera-Nieves, Jesús

2016-01-01

The sphingosine-1-phosphate receptor-1 (S1P1) agonist ozanimod ameliorates ulcerative colitis, yet its mechanism of action is unknown. Here we examine the cell subsets that express S1P1 in intestine using S1P1-eGFP mice, the regulation of S1P1 expression in lymphocytes after administration of DSS, after colitis induced by transfer of CD4+CD45RBhi cells and by crossing a mouse with TNF-driven ileitis with S1P1-eGFP mice. We then assayed the expression of enzymes that regulate intestinal S1P levels, and the effect of FTY720 on lymphocyte behavior and S1P1 expression. We found that not only T and B cells express S1P1, but also dendritic (DC) and endothelial cells. Furthermore, chronic but not acute inflammatory signals increased S1P1 expression, while the enzymes that control tissue S1P levels in mice and humans with IBD were uniformly dysregulated, favoring synthesis over degradation. Finally, we observed that FTY720 reduced T cell velocity and induced S1P1 degradation and retention of naïve but not effector T cells. Our data demonstrate that chronic inflammation modulates S1P1 expression and tissue S1P levels and suggests that the anti-inflammatory properties of S1PR agonists might not be solely due to their lymphopenic effects, but also due to potential effects on DC migration and vascular barrier function. PMID:27049060

The impact of eicosanoids on the crosstalk between innate and adaptive immunity: the key roles of dendritic cells.

PubMed

Harizi, H; Gualde, N

2005-06-01

The innate immune response is essentially the first line of defense against an invading pathogen. Through specialized receptors, known as pattern recognition receptors, especially Toll-like receptors, specialized cells of myeloid origin, including macrophages and dendritic cells (DCs) are able to phagocytose microorganisms and induce an innate inflammatory response. Although B and T lymphocytes recognize tissue antigens with high specificity, they are unable to initiate immune responses. The decision to activate an appropriate immune response is made by unique DC, the most professional antigen-presenting cells (APCs) which control the responses of several types of lymphocytes and play central role in the transition between innate and adaptive immunity. Increased secretion of inflammatory endogenous mediators such as cytokines and arachidonic acid-derived lipid mediators, also termed eicosanoids, can activate APC, particularly DC, which in turn induce an adaptive immune response. There is an increasing evidence that eicosanoids play an important role in connecting innate and adaptive immunity by acting on cells of both systems. Prostanoids, a major class of eicosanoids, have a great impact on inflammatory and immune responses. PGE(2) is one of the best known and most well-characterized prostanoids in terms of immunomodulation. Although cytokines are known as key regulators of immunity, eicosanoids, including PGE(2), PGD(2), LTB(4), and LTC(4), may also affect cells of immune system by modulating cytokine release, cell differentiation, survival, migration, antigen presentation, and apoptosis. By acting on various aspects of immune and inflammatory reactions, these lipid mediators emerge as key regulators of the crosstalk between innate and adaptive immunity.

“Subpial Fan Cell” — A Class of Calretinin Neuron in Layer 1 of Adult Monkey Prefrontal Cortex

PubMed Central

Gabbott, Paul L. A.

2016-01-01

Layer 1 of the cortex contains populations of neurochemically distinct neurons and afferent fibers which markedly affect neural activity in the apical dendritic tufts of pyramidal cells. Understanding the causal mechanisms requires knowledge of the cellular architecture and synaptic organization of layer 1. This study has identified eight morphological classes of calretinin immunopositive (CRet+) neurons (including Cajal-Retzius cells) in layer 1 of the prefrontal cortex (PFC) in adult monkey (Macaca fasicularis), with a distinct class — termed “subpial fan (SPF) cell” — described in detail. SPF cells were rare horizontal unipolar CRet+ cells located directly beneath the pia with a single thick primary dendrite that branched into a characteristic fan-like dendritic tree tangential to the pial surface. Dendrites had spines, filamentous processes and thorny branchlets. SPF cells lay millimeters apart with intralaminar axons that ramified widely in upper layer 1. Such cells were GABA immunonegative (-) and occurred in areas beyond PFC. Interspersed amidst SPF cells displaying normal structural integrity were degenerating CRet+ neurons (including SPF cells) and clumps of lipofuscin-rich cellular debris. The number of degenerating SPF cells increased during adulthood. Ultrastructural analyses indicated SPF cell somata received asymmetric (A — presumed excitatory) and symmetric (S — presumed inhibitory) synaptic contacts. Proximal dendritic shafts received mainly S-type and distal shafts mostly A-type input. All dendritic thorns and most dendritic spines received both synapse types. The tangential areal density of SPF cell axonal varicosities varied radially from parent somata — with dense clusters in more distal zones. All boutons formed A-type contacts with CRet- structures. The main post-synaptic targets were dendritic shafts (67%; mostly spine-bearing) and dendritic spines (24%). SPF-SPF cell innervation was not observed. Morphometry of SPF cells indicated a unique class of CRet+/GABA- neuron in adult monkey PFC — possibly a subtype of persisting Cajal-Retzius cell. The distribution and connectivity of SPF cells suggest they act as integrative hubs in upper layer 1 during postnatal maturation. The main synaptic output of SPF cells likely provides a transminicolumnar excitatory influence across swathes of apical dendritic tufts — thus affecting information processing in discrete patches of layer 1 in adult monkey PFC. PMID:27147978

Foxp1 Regulates Cortical Radial Migration and Neuronal Morphogenesis in Developing Cerebral Cortex

PubMed Central

Li, Xue; Xiao, Jian; Fröhlich, Henning; Tu, Xiaomeng; Li, Lianlian; Xu, Yue; Cao, Huateng; Qu, Jia; Rappold, Gudrun A.; Chen, Jie-Guang

2015-01-01

FOXP1 is a member of FOXP subfamily transcription factors. Mutations in FOXP1 gene have been found in various development-related cognitive disorders. However, little is known about the etiology of these symptoms, and specifically the function of FOXP1 in neuronal development. Here, we report that suppression of Foxp1 expression in mouse cerebral cortex led to a neuronal migration defect, which was rescued by overexpression of Foxp1. Mice with Foxp1 knockdown exhibited ectopic neurons in deep layers of the cortex postnatally. The neuronal differentiation of Foxp1-downregulated cells was normal. However, morphological analysis showed that the neurons with Foxp1 deficiency had an inhibited axonal growth in vitro and a weakened transition from multipolar to bipolar in vivo. Moreover, we found that the expression of Foxp1 modulated the dendritic maturation of neurons at a late postnatal date. Our results demonstrate critical roles of Foxp1 in the radial migration and morphogenesis of cortical neurons during development. This study may shed light on the complex relationship between neuronal development and the related cognitive disorders. PMID:26010426

Secretory IgA in complex with Lactobacillus rhamnosus potentiates mucosal dendritic cell-mediated Treg cell differentiation via TLR regulatory proteins, RALDH2 and secretion of IL-10 and TGF-β

PubMed Central

Mikulic, Josip; Longet, Stéphanie; Favre, Laurent; Benyacoub, Jalil; Corthesy, Blaise

2017-01-01

The importance of secretory IgA in controlling the microbiota is well known, yet how the antibody affects the perception of the commensals by the local immune system is still poorly defined. We have previously shown that the transport of secretory IgA in complex with bacteria across intestinal microfold cells results in an association with dendritic cells in Peyer’s patches. However, the consequences of such an interaction on dendritic cell conditioning have not been elucidated. In this study, we analyzed the impact of the commensal Lactobacillus rhamnosus, alone or associated with secretory IgA, on the responsiveness of dendritic cells freshly recovered from mouse Peyer’s patches, mesenteric lymph nodes, and spleen. Lactobacillus rhamnosus-conditioned mucosal dendritic cells are characterized by increased expression of Toll-like receptor regulatory proteins [including single immunoglobulin interleukin-1 receptor-related molecule, suppressor of cytokine signaling 1, and Toll-interacting molecule] and retinaldehyde dehydrogenase 2, low surface expression of co-stimulatory markers, high anti- versus pro-inflammatory cytokine production ratios, and induction of T regulatory cells with suppressive function. Association with secretory IgA enhanced the anti-inflammatory/regulatory Lactobacillus rhamnosus-induced conditioning of mucosal dendritic cells, particularly in Peyer’s patches. At the systemic level, activation of splenic dendritic cells exposed to Lactobacillus rhamnosus was partially dampened upon association with secretory IgA. These data suggest that secretory IgA, through coating of commensal bacteria, contributes to the conditioning of mucosal dendritic cells toward tolerogenic profiles essential for the maintenance of intestinal homeostasis. PMID:26972771

Langerhans' cell expression of the selectin ligand, sialyl Lewis x.

PubMed Central

Ross, E L; Barker, J N; Allen, M H; Chu, A C; Groves, R W; MacDonald, D M

1994-01-01

Cellular adhesion molecules play a central role in leucocyte migration through peripheral blood and tissues. A crucial stage in these events in selectin-mediated adhesion involving E-selectin expressed on activated endothelium interacting with a range of carbohydrate ligands expressed by specific subpopulations of leucocytes. As such mechanisms may be relevant to bone marrow-derived dendritic epidermal Langerhans' cell (LC) migration, expression of these carbohydrate ligands was assessed immunocytochemically in whole skin biopsies and in epidermal cell suspensions obtained from adult humans. Double-labelling experiments revealed that sialyl Lewis x, recognized by the monoclonal antibody CSLEX1, was expressed on epidermal LC (n = 9). Furthermore, expression was enhanced at 24 hr following epicutaneous application of antigen and in the inflammatory disorder psoriasis (n = 10). E-selectin was concomitantly strongly expressed on dermal endothelium in psoriasis and allergic contact dermatitis. Intradermal injection of the T-cell-derived cytokine interferon-gamma (IFN-gamma) led to increased LC expression of sialyl Lewis x. In epidermal cell suspensions, in contrast to keratinocytes, CD1a+ cells expressed sialyl Lewis x, intensity of which was enhanced after 4 days in culture. CSLEX1 staining could be abolished and CD15 (non-sialated Lewis x) expression induced by saponification and treatment with neuraminidase. Expression of other selectin ligands was also examined. While the cutaneous lymphocyte antigen defined by the monoclonal antibody HECA-452 reacted with a small minority of LC, sialyl Lewis a and sulphatide were not expressed under any experimental conditions. These studies indicate that E-selectin-sialyl Lewis x interactions are potentially important in LC migration, both into and out of skin. Images Figure 2 Figure 3 Figure 5 Figure 6 PMID:7512530

Visualization of T Cell-Regulated Monocyte Clusters Mediating Keratinocyte Death in Acquired Cutaneous Immunity.

PubMed

Liu, Zheng; Yang, Fei; Zheng, Hao; Fan, Zhan; Qiao, Sha; Liu, Lei; Tao, Juan; Luo, Qingming; Zhang, Zhihong

2018-06-01

It remains unclear how monocytes are mobilized to amplify inflammatory reactions in T cell-mediated adaptive immunity. Here, we investigate dynamic cellular events in the cascade of inflammatory responses through intravital imaging of a multicolor-labeled murine contact hypersensitivity model. We found that monocytes formed clusters around hair follicles in the contact hypersensitivity model. In this process, effector T cells encountered dendritic cells under regions of monocyte clusters and secreted IFN-γ, which mobilizes CCR2-dependent monocyte interstitial migration and CXCR2-dependent monocyte cluster formation. We showed that hair follicles shaped the inflammatory microenvironment for communication among the monocytes, keratinocytes, and effector T cells. After disrupting the T cell-mobilized monocyte clusters through CXCR2 antagonization, monocyte activation and keratinocyte apoptosis were significantly inhibited. Our study provides a new perspective on effector T cell-regulated monocyte behavior, which amplifies the inflammatory reaction in acquired cutaneous immunity. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

The number and growth pattern of plasmacytoid dendritic cells vary in different types of reactive lymph nodes: an immunohistochemical study.

PubMed

Rollins-Raval, Marian A; Marafioti, Teresa; Swerdlow, Steven H; Roth, Christine G

2013-06-01

Plasmacytoid dendritic cells, which play a fundamental role in the innate immune response, are best known for their presence in hyaline-vascular Castleman disease and histiocytic necrotizing lymphadenitis. The relative number and distribution in many reactive entities as detected using more sensitive methods are uncertain, and their diagnostic implications are unknown. Immunohistochemical studies for plasmacytoid dendritic cell-associated markers CD123 and CD2AP were performed on 42 lymph nodes with hyaline-vascular Castleman disease, histiocytic necrotizing lymphadenitis, sarcoidosis, necrotizing granulomatous inflammation, viral infection, dermatopathic lymphadenopathy, autoimmune disease, and a histologic pattern compatible with toxoplasmosis. The overall plasmacytoid dendritic cell numbers and growth patterns (tight aggregates, loose aggregates/clusters, scattered single cells) were assessed. Plasmacytoid dendritic cells were present in all cases and were predominantly distributed in loose aggregates/clusters or singly. They were most numerous in granulomatous inflammation and histiocytic necrotizing lymphadenitis, whereas viral infections showed the fewest overall numbers and a predominant pattern of scattered single cells. Tight aggregates of plasmacytoid dendritic cells were most numerous in hyaline-vascular Castleman disease (100% sensitive, 68% specific). Plasmacytoid dendritic cells are not limited to a small number of reactive lymphadenopathies but are found in many reactive processes, often with a predominant pattern of loose aggregates/clusters and scattered single cells. However, tight aggregates were a characteristic feature of hyaline-vascular Castleman disease, and viral infections typically showed only few scattered cells distributed singly. Copyright © 2013 Elsevier Inc. All rights reserved.

Dendritic Cells Exposed to MVA-Based HIV-1 Vaccine Induce Highly Functional HIV-1-Specific CD8+ T Cell Responses in HIV-1-Infected Individuals

PubMed Central

Climent, Núria; Guerra, Susana; García, Felipe; Rovira, Cristina; Miralles, Laia; Gómez, Carmen Elena; Piqué, Núria; Gil, Cristina; Gatell, José María; Esteban, Mariano; Gallart, Teresa

2011-01-01

Currently, MVA virus vectors carrying HIV-1 genes are being developed as HIV-1/AIDS prophylactic/therapeutic vaccines. Nevertheless, little is known about the impact of these vectors on human dendritic cells (DC) and their capacity to present HIV-1 antigens to human HIV-specific T cells. This study aimed to characterize the interaction of MVA and MVA expressing the HIV-1 genes Env-Gag-Pol-Nef of clade B (referred to as MVA-B) in human monocyte-derived dendritic cells (MDDC) and the subsequent processes of HIV-1 antigen presentation and activation of memory HIV-1-specific T lymphocytes. For these purposes, we performed ex vivo assays with MDDC and autologous lymphocytes from asymptomatic HIV-infected patients. Infection of MDDC with MVA-B or MVA, at the optimal dose of 0.3 PFU/MDDC, induced by itself a moderate degree of maturation of MDDC, involving secretion of cytokines and chemokines (IL1-ra, IL-7, TNF-α, IL-6, IL-12, IL-15, IL-8, MCP-1, MIP-1α, MIP-1β, RANTES, IP-10, MIG, and IFN-α). MDDC infected with MVA or MVA-B and following a period of 48 h or 72 h of maturation were able to migrate toward CCL19 or CCL21 chemokine gradients. MVA-B infection induced apoptosis of the infected cells and the resulting apoptotic bodies were engulfed by the uninfected MDDC, which cross-presented HIV-1 antigens to autologous CD8+ T lymphocytes. MVA-B-infected MDDC co-cultured with autologous T lymphocytes induced a highly functional HIV-specific CD8+ T cell response including proliferation, secretion of IFN-γ, IL-2, TNF-α, MIP-1β, MIP-1α, RANTES and IL-6, and strong cytotoxic activity against autologous HIV-1-infected CD4+ T lymphocytes. These results evidence the adjuvant role of the vector itself (MVA) and support the clinical development of prophylactic and therapeutic anti-HIV vaccines based on MVA-B. PMID:21625608

Influence of thyroid in nervous system growth.

PubMed

Mussa, G C; Mussa, F; Bretto, R; Zambelli, M C; Silvestro, L

2001-08-01

Nervous system growth and differentiation are closely correlated with the presence of iodine and thyroid hormones in initial development stages. In the human species, encephalon maturation during the first quarter of pregnancy is affected according to recent studies by the transplacenta passage of maternal thyroid hormones while it depends on initial iodiothyronin secretion by the foetal gland after the 12th week of pregnancy. Thyroid hormone deficiency during nervous system development causes altered noble nervous cells, such as the pyramidal cortical and Purkinje cells, during glial cell proliferation and differentiation alike. Neurons present cell hypoplasia with reduced axon count, dendritic branching, synaptic spikes and interneuron connections. Oligodendrocytes decrease in number and average myelin content consequently drops. Biochemical studies on hypothyroid rats have demonstrated alterations to neuron intraplasmatic microtubule content and organisation, changed mitochondria number and arrangement and anomalies in T3 nuclear and citoplasmatic receptor maturation. Alterations to microtubules are probably responsible for involvement of the axon-dendrite system, and are the consequence of deficient thyroid hormone action on the mitochondria, the mitochondria enzymes and proteins associated with microtubules. Nuclear and citoplasmatic receptors have been identified and gene clonation studies have shown two families of nuclear receptors that include several sub-groups in their turn. A complex scheme of temporal and spatial expression of these receptors exists, so they probably contribute with one complementary function, although their physiological role differs. The action of thyroid hormones occurs by changing cell protein levels because of their regulation at the transcriptional or post-transcriptional level. Genes submitted to thyroid hormone control are either expressed by oligodendrytes, which are myelin protein coders or glial differentiation mediators, or are nervous cell specific, genes coding neurotropins or proteins involved in synaptic excitation. The use of new PMRS and MRI non-invasive techniques has enabled identification of metabolic and biochemical markers for alterations in the encephalon of untreated hypothyroid children. Even an excess of thyroid hormones during early nervous system development can cause permanent effects. Hyperthyroidism in fact initially induces accelerated maturation process including cell migration and differentiation, extension of dendritic processes and synaptogenesis but a later excess of thyroid hormones causes reduction of the total number of dendritic spikes, due to early interruption of neuron proliferation. Experimental studies and clinical research have clarified not only the correlation between nervous system maturation and thyroid function during early development stages and the certain finding from this research is that both excess and deficient thyroid hormones can cause permanent anatomo-functional alterations to the nervous system.

Targeting Toll-like receptor 7/8 enhances uptake of apoptotic leukemic cells by monocyte-derived dendritic cells but interferes with subsequent cytokine-induced maturation.

PubMed

van den Ancker, Willemijn; van Luijn, Marvin M; Ruben, Jurjen M; Westers, Theresia M; Bontkes, Hetty J; Ossenkoppele, Gert J; de Gruijl, Tanja D; van de Loosdrecht, Arjan A

2011-01-01

Therapeutic vaccination with dendritic cells (DC) is an emerging investigational therapy for eradication of minimal residual disease in acute myeloid leukemia. Various strategies are being explored in manufacturing DC vaccines ex vivo, e.g., monocyte-derived DC (MoDC) loaded with leukemia-associated antigens (LAA). However, the optimal source of LAA and the choice of DC-activating stimuli are still not well defined. Here, loading with leukemic cell preparations (harboring both unknown and known LAA) was explored in combination with a DC maturation-inducing cytokine cocktail (CC; IL-1β, IL-6, TNF-α, and PGE(2)) and Toll-like receptor ligands (TLR-L) to optimize uptake. Since heat shock induced apoptotic blasts were more efficiently taken up than lysates, we focused on uptake of apoptotic leukemic cells. Uptake of apoptotic blast was further enhanced by the TLR7/8-L R848 (20-30%); in contrast, CC-induced maturation inhibited uptake. CC, and to a lesser extent R848, enhanced the ability of MoDC to migrate and stimulate T cells. Furthermore, class II-associated invariant chain peptide expression was down-modulated after R848- or CC-induced maturation, indicating enhanced processing and presentation of antigenic peptides. To improve both uptake and maturation, leukemic cells and MoDC were co-incubated with R848 for 24 h followed by addition of CC. However, this approach interfered with CC-mediated MoDC maturation as indicated by diminished migratory and T cell stimulatory capacity, and the absence of IL-12 production. Taken together, our data demonstrate that even though R848 improved uptake of apoptotic leukemic cells, the sequential use of R848 and CC is counter-indicated due to its adverse effects on MoDC maturation.

The transcription factor IRF8 counteracts BCR-ABL to rescue dendritic cell development in chronic myelogenous leukemia.

PubMed

Watanabe, Tomoya; Hotta, Chie; Koizumi, Shin-ichi; Miyashita, Kazuho; Nakabayashi, Jun; Kurotaki, Daisuke; Sato, Go R; Yamamoto, Michio; Nakazawa, Masatoshi; Fujita, Hiroyuki; Sakai, Rika; Fujisawa, Shin; Nishiyama, Akira; Ikezawa, Zenro; Aihara, Michiko; Ishigatsubo, Yoshiaki; Tamura, Tomohiko

2013-11-15

BCR-ABL tyrosine kinase inhibitors (TKI) have dramatically improved therapy for chronic myelogenous leukemia (CML). However, several problems leading to TKI resistance still impede a complete cure of this disease. IFN regulatory factor-8 (IRF8) is a transcription factor essential for the development and functions of immune cells, including dendritic cells. Irf8(-/-) mice develop a CML-like disease and IRF8 expression is downregulated in patients with CML, suggesting that IRF8 is involved in the pathogenesis of CML. In this study, by using a murine CML model, we show that BCR-ABL strongly inhibits a generation of dendritic cells from an early stage of their differentiation in vivo, concomitant with suppression of Irf8 expression. Forced expression of IRF8 overrode BCR-ABL (both wild-type and T315I-mutated) to rescue dendritic cell development in vitro, indicating that the suppression of Irf8 causes dendritic cell deficiency. Gene expression profiling revealed that IRF8 restored the expression of a significant portion of BCR-ABL-dysregulated genes and predicted that BCR-ABL has immune-stimulatory potential. Indeed, IRF8-rescued BCR-ABL-expressing dendritic cells were capable of inducing CTLs more efficiently than control dendritic cells. Altogether, our findings suggest that IRF8 is an attractive target in next-generation therapies for CML. ©2013 AACR

Hypofractionated Irradiation Has Immune Stimulatory Potential and Induces a Timely Restricted Infiltration of Immune Cells in Colon Cancer Tumors

PubMed Central

Frey, Benjamin; Rückert, Michael; Weber, Julia; Mayr, Xaver; Derer, Anja; Lotter, Michael; Bert, Christoph; Rödel, Franz; Fietkau, Rainer; Gaipl, Udo S.

2017-01-01

In addition to locally controlling the tumor, hypofractionated radiotherapy (RT) particularly aims to activate immune cells in the RT-modified microenvironment. Therefore, we examined whether hypofractionated RT can activate dendritic cells (DCs), induce immune cell infiltration in tumors, and how the chronology of immune cell migration into tumors occurs to gain knowledge for future definition of radiation breaks and inclusion of immunotherapy. Colorectal cancer treatments offer only limited survival benefit, and immunobiological principles for additional therapies need to be explored with preclinical models. The impact of hypofractionated RT on CT26 colon cancer tumor cell death, migration of DCs toward supernatants (SN) of tumor cells, and activation of DCs by SN were analyzed. The subcutaneous tumor of a BALB/c-CT26 mouse model was locally irradiated with 2 × 5 Gy, the tumor volume was monitored, and the infiltration of immune cells in the tumor was determined by flow cytometry daily. Hypofractionated RT induced a mixture of apoptotic and necrotic CT26 cells, which is known to be in particular immunogenic. DCs that migrated toward SN of CT26 cells particularly upregulated the activation markers CD80 and CD86 when in contact with SN of irradiated tumor cells. After hypofractionated RT, the tumor outgrowth was significantly retarded and in the irradiated tumors an increased infiltration of macrophages (CD11bhigh/F4-80+) and DCs (MHC-II+), but only between day 5 and 10 after the first irradiation, takes place. While CD4+ T cells migrated into non-irradiated and irradiated tumors, CD8+ T cells were only found in tumors that had been irradiated and they were highly increased at day 8 after the first irradiation. Myeloid-derived suppressor cells and regulatory T cells show regular turnover in irradiated and non-irradiated tumors. Tumor cell-specific anti-IgM antibodies were enhanced in the serum of animals with irradiated tumors. We conclude that hypofractionated RT suffices to activate DCs and to induce infiltration of innate and adaptive immune cells into solid colorectal tumors. However, the presence of immune cells in the tumor which are beneficial for antitumor immune responses is timely restricted. These findings should be considered when innovative multimodal tumor treatment protocols of distinct RT with immune therapies are designed and clinically implemented. PMID:28337197

Can dendritic cells see light?

NASA Astrophysics Data System (ADS)

Chen, Aaron C.-H.; Huang, Ying-Ying; Sharma, Sulbha K.; Hamblin, Michael R.

2010-02-01

There are many reports showing that low-level light/laser therapy (LLLT) can enhance wound healing, upregulate cell proliferation and has anti-apoptotic effects by activating intracellular protective genes. In the field of immune response study, it is not known with any certainty whether light/laser is proinflammatory or anti-inflammatory. Increasingly in recent times dendritic cells have been found to play an important role in inflammation and the immunological response. In this study, we try to look at the impact of low level near infrared light (810-nm) on murine bone-marrow derived dendritic cells. Changes in surface markers, including MHC II, CD80 and CD11c and the secretion of interleukins induced by light may provide additional evidence to reveal the mystery of how light affects the maturation of dendritic cells as well how these light-induced mature dendritic cells would affect the activation of adaptive immune response.

CT findings associated with blastic plasmacytoid dendritic cell neoplasm: a case report

PubMed Central

Choi, Jung W; Jeong, Katherine; Sokol, Lubomir

2016-01-01

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy that is frequently misdiagnosed. We present a case of a 53-year-old man diagnosed with blastic plasmacytoid dendritic cell neoplasm with extensive computed tomography (CT) findings and provide an imaging focused review of this uncommon malignancy. PMID:27504192

Phenotype and function of CD209+ bovine blood dendritic cells, monocyte-derived-dendritic cells and monocyte-derived macrophages

USDA-ARS?s Scientific Manuscript database

Phylogenic comparisons of the mononuclear phagocyte system (MPS) of humans and mice demonstrate phenotypic divergence of dendritic cell (DC) subsets that play similar roles in innate and adaptive immunity. Although differing in phenotype, DC can be classified into four groups according to ontogeny a...

A Comparison between Growth Morphology of "Eutectic" Cells/Dendrites and Single-Phase Cells/Dendrites

NASA Technical Reports Server (NTRS)

Tewari, S. N.; Raj, S. V.; Locci, I. E.

2003-01-01

Directionally solidified (DS) intermetallic and ceramic-based eutectic alloys with an in-situ composite microstructure containing finely distributed, long aspect ratio, fiber, or plate reinforcements are being seriously examined for several advanced aero-propulsion applications. In designing these alloys, additional solutes need to be added to the base eutectic composition in order to improve heir high-temperature strength, and provide for adequate toughness and resistance to environmental degradation. Solute addition, however, promotes instability at the planar liquid-solid interface resulting in the formation of two-phase eutectic "colonies." Because morphology of eutectic colonies is very similar to the single-phase cells and dendrites, the stability analysis of Mullins and Sekerka has been extended to describe their formation. Onset of their formation shows a good agreement with this approach; however, unlike the single-phase cells and dendrites, there is limited examination of their growth speed dependence of spacing, morphology, and spatial distribution. The purpose of this study is to compare the growth speed dependence of the morphology, spacing, and spatial distribution of eutectic cells and dendrites with that for the single-phase cells and dendrites.

Responses to Microbial Challenges by SLAMF Receptors

PubMed Central

van Driel, Boaz Job; Liao, Gongxian; Engel, Pablo; Terhorst, Cox

2016-01-01

The SLAMF family (SLAMF) of cell surface glycoproteins is comprised of nine glycoproteins and while SLAMF1, 3, 5, 6, 7, 8, and 9 are self-ligand receptors, SLAMF2 and SLAMF4 interact with each other. Their interactions induce signal transduction networks in trans, thereby shaping immune cell–cell communications. Collectively, these receptors modulate a wide range of functions, such as myeloid cell and lymphocyte development, and T and B cell responses to microbes and parasites. In addition, several SLAMF receptors serve as microbial sensors, which either positively or negatively modulate the function of macrophages, dendritic cells, neutrophils, and NK cells in response to microbial challenges. The SLAMF receptor–microbe interactions contribute both to intracellular microbicidal activity as well as to migration of phagocytes to the site of inflammation. In this review, we describe the current knowledge on how the SLAMF receptors and their specific adapters SLAM-associated protein and EAT-2 regulate innate and adaptive immune responses to microbes. PMID:26834746

p-Hydroxylcinnamaldehyde induces the differentiation of oesophageal carcinoma cells via the cAMP-RhoA-MAPK signalling pathway

PubMed Central

Ma, Ming; Zhao, Lian-mei; Yang, Xing-xiao; Shan, Ya-nan; Cui, Wen-xuan; Chen, Liang; Shan, Bao-en

2016-01-01

p-Hydroxylcinnamaldehyde (CMSP) has been identified as an inhibitor of the growth of various cancer cells. However, its function in oesophageal squamous cell carcinoma (ESCC) and the underlying mechanism remain unclear. The aim of the present study was to characterize the differentiation effects of CMSP, as well as its mechanism in the differentiation of ESCC Kyse30 and TE-13 cells. The function of CMSP in the viability, colony formation, migration and invasion of Kyse30 and TE-13 cells was determined by MTS, colony-formation, wound healing and transwell assays. Western blotting and pull-down assays were used to investigate the effect of CMSP on the expression level of malignant markers of ESCC, as well as the activity of MAPKs, RhoA and GTP-RhoA in Kyse30 and TE-13 cells. We found that CMSP could inhibit proliferation and migration and induce Kyse30 and TE-13 cell differentiation, characterized by dendrite-like outgrowth, decreased expression of tumour-associated antigens, as well as the decreased expression of malignant markers. Furthermore, increased cAMP, p-P38 and decreased activities of ERK, JNK and GTP-RhoA, were detected after treatment with CMSP. These results indicated that CMSP induced the differentiation of Kyse30 and TE-13 cells through mediating the cAMP-RhoA-MAPK axis, which might provide new potential strategies for ESCC treatment. PMID:27501997

Maintenance of dendritic spine morphology by partitioning-defective 1b through regulation of microtubule growth.

PubMed

Hayashi, Kenji; Suzuki, Atsushi; Hirai, Syu-ichi; Kurihara, Yasuyuki; Hoogenraad, Casper C; Ohno, Shigeo

2011-08-24

Dendritic spines are postsynaptic structures that receive excitatory synaptic input from presynaptic terminals. Actin and its regulatory proteins play a central role in morphogenesis of dendritic spines. In addition, recent studies have revealed that microtubules are indispensable for the maintenance of mature dendritic spine morphology by stochastically invading dendritic spines and regulating dendritic localization of p140Cap, which is required for actin reorganization. However, the regulatory mechanisms of microtubule dynamics remain poorly understood. Partitioning-defective 1b (PAR1b), a cell polarity-regulating serine/threonine protein kinase, is thought to regulate microtubule dynamics by inhibiting microtubule binding of microtubule-associated proteins. Results from the present study demonstrated that PAR1b participates in the maintenance of mature dendritic spine morphology in mouse hippocampal neurons. Immunofluorescent analysis revealed PAR1b localization in the dendrites, which was concentrated in dendritic spines of mature neurons. PAR1b knock-down cells exhibited decreased mushroom-like dendritic spines, as well as increased filopodia-like dendritic protrusions, with no effect on the number of protrusions. Live imaging of microtubule plus-end tracking proteins directly revealed decreases in distance and duration of microtubule growth following PAR1b knockdown in a neuroblastoma cell line and in dendrites of hippocampal neurons. In addition, reduced accumulation of GFP-p140Cap in dendritic protrusions was confirmed in PAR1b knock-down neurons. In conclusion, the present results suggested a novel function for PAR1b in the maintenance of mature dendritic spine morphology by regulating microtubule growth and the accumulation of p140Cap in dendritic spines.

Human dendritic cells in the severe combined immunodeficiency mouse model: their potentiating role in the allergic reaction.

PubMed

Hammad, H; Duez, C; Fahy, O; Tsicopoulos, A; André, C; Wallaert, B; Lebecque, S; Tonnel, A B; Pestel, J

2000-04-01

Dendritic cells (DCs) are present in the lungs and airways of healthy and allergic subjects where they are exposed to inhaled antigens. After the uptake of antigens, DCs migrate to lymphoid organs where T cells initiate and control the immune response. The migratory properties of DCs are an essential component of their function but remain unclear in the situation of allergic diseases. To better understand the role of DCs in response to allergens, we first investigated their presence in an original experimental model of allergic asthma: the humanized severe combined immunodeficiency (SCID) mouse reconstituted with peripheral blood mononuclear cells from patients sensitive to Dermatophagoides pteronyssinus (Dpt). Human DCs were detected in lungs of mice developing an inflammatory pulmonary infiltrate and appeared to be mainly located in the alveolar spaces. In a second step, human DCs were generated in vitro from monocytes and injected into naive SCID mice exposed or not exposed to Dpt aerosols. Their migratory behavior was explored, as well as their potential role in modulating the IgE production after exposure to Dpt. After exposure to Dpt, the number of DCs present in airways decreased, while it increased into the spleen and thymus of the mice. The IgE production increased in the presence of DCs as compared with mice not injected with DCs. These results suggest that DCs may play a role in the pulmonary allergic reaction developed in response to Dpt in SCID mice.

Altered Macrophage and Dendritic Cell Response in Mif−/− Mice Reveals a Role of Mif for Inflammatory-Th1 Response in Type 1 Diabetes

PubMed Central

Vazquez-Mendoza, Alicia

2016-01-01

Macrophage migration inhibitory factor (Mif) is highly expressed in type 1 diabetes mellitus (T1DM). However, there is limited information about how Mif influences the activation of macrophages (Mφ) and dendritic cells (DC) in T1DM. To address this issue, we induced T1DM by administering multiple low doses of streptozotocin (STZ) to Mif−/− or wild-type (Wt) BALB/c mice. We found that Mif−/− mice treated with STZ (Mif−/−STZ) developed lower levels of hyperglycemia, inflammatory cytokines, and specific pancreatic islet antigen- (PIAg-) IgG and displayed reduced cellular infiltration into the pancreatic islets compared to Wt mice treated with STZ (WtSTZ). Moreover, Mφ and DC from Mif−/−STZ displayed lower expression of MHC-II, costimulatory molecules CD80, CD86, and CD40, Toll-like receptor- (TLR-) 2, and TLR-4 than WtSTZ. These changes were associated with a reduced capacity of Mφ and DC from Mif−/−STZ to induce proliferation in ovalbumin-specific T cells. All the deficiencies observed in Mif−/−STZ were recovered by exogenous administration of recombinant Mif. These findings suggest that Mif plays a role in the molecular mechanisms of Mφ and DC activation and drives T cell responses involved in the pathology of T1DM. Therefore, Mif is a potential therapeutic target to reduce the pathology of T1DM. PMID:27699180

Altered Macrophage and Dendritic Cell Response in Mif-/- Mice Reveals a Role of Mif for Inflammatory-Th1 Response in Type 1 Diabetes.

PubMed

Sánchez-Zamora, Yuriko Itzel; Juarez-Avelar, Imelda; Vazquez-Mendoza, Alicia; Hiriart, Marcia; Rodriguez-Sosa, Miriam

2016-01-01

Macrophage migration inhibitory factor (Mif) is highly expressed in type 1 diabetes mellitus (T1DM). However, there is limited information about how Mif influences the activation of macrophages (M φ ) and dendritic cells (DC) in T1DM. To address this issue, we induced T1DM by administering multiple low doses of streptozotocin (STZ) to Mif-/- or wild-type (Wt) BALB/c mice. We found that Mif-/- mice treated with STZ ( Mif-/- STZ) developed lower levels of hyperglycemia, inflammatory cytokines, and specific pancreatic islet antigen- (PIAg-) IgG and displayed reduced cellular infiltration into the pancreatic islets compared to Wt mice treated with STZ (WtSTZ). Moreover, M φ and DC from Mif-/- STZ displayed lower expression of MHC-II, costimulatory molecules CD80, CD86, and CD40, Toll-like receptor- (TLR-) 2, and TLR-4 than WtSTZ. These changes were associated with a reduced capacity of M φ and DC from Mif-/- STZ to induce proliferation in ovalbumin-specific T cells. All the deficiencies observed in Mif-/- STZ were recovered by exogenous administration of recombinant Mif. These findings suggest that Mif plays a role in the molecular mechanisms of M φ and DC activation and drives T cell responses involved in the pathology of T1DM. Therefore, Mif is a potential therapeutic target to reduce the pathology of T1DM.

Induction of monocyte chemoattractant protein-1 and interleukin-10 by TGFbeta1 in melanoma enhances tumor infiltration and immunosuppression.

PubMed

Díaz-Valdés, Nancy; Basagoiti, María; Dotor, Javier; Aranda, Fernando; Monreal, Iñaki; Riezu-Boj, José Ignacio; Borrás-Cuesta, Francisco; Sarobe, Pablo; Feijoó, Esperanza

2011-02-01

Melanoma progression is associated with the expression of different growth factors, cytokines, and chemokines. Because TGFβ1 is a pleiotropic cytokine involved not only in physiologic processes but also in cancer development, we analyzed in A375 human melanoma cells, the effect of TGFβ1 on monocyte chemoattractant protein-1 (MCP-1) and interleukin-10 (IL-10) expression, two known factors responsible for melanoma progression. TGFβ1 increased the expression of MCP-1 and IL-10 in A375 cells, an effect mediated by the cross-talk between Smad, PI3K (phosphoinositide 3-kinase)/AKT, and BRAF-MAPK (mitogen activated protein kinase) signaling pathways. Supernatants from TGFβ1-treated A375 cells enhanced MCP-1-dependent migration of monocytes, which, in turn, expressed high levels of TGF,β1, bFGF, and VEGF mRNA. Moreover, these supernatants also inhibited functional properties of dendritic cells through IL-10-dependent mechanisms. When using in vitro, the TGFβ1-blocking peptide P144, TGFβ1-dependent Smad3 phosphorylation, and expression of MCP-1 and IL-10 were inhibited. In vivo, treatment of A375 tumor-bearing athymic mice with P144 significantly reduced tumor growth, associated with a lower macrophage infiltrate and decreased intratumor MCP-1 and VEGF levels, as well as angiogenesis. Finally, in C57BL/6 mice with B16-OVA melanoma tumors, when administered with immunotherapy, P144 decreased tumor growth and intratumor IL-10 levels, linked to enhanced activation of dendritic cells and natural killer cells, as well as anti-OVA T-cell responses. These results show new effects of TGFβ1 on melanoma cells, which promote tumor progression and immunosuppression, strongly reinforcing the relevance of this cytokine as a molecular target in melanoma.

Characterization of SLCO5A1/OATP5A1, a Solute Carrier Transport Protein with Non-Classical Function

PubMed Central

Sebastian, Katrin; Detro-Dassen, Silvia; Rinis, Natalie; Fahrenkamp, Dirk; Müller-Newen, Gerhard; Merk, Hans F.; Schmalzing, Günther

2013-01-01

Organic anion transporting polypeptides (OATP/SLCO) have been identified to mediate the uptake of a broad range of mainly amphipathic molecules. Human OATP5A1 was found to be expressed in the epithelium of many cancerous and non-cancerous tissues throughout the body but protein characterization and functional analysis have not yet been performed. This study focused on the biochemical characterization of OATP5A1 using Xenopus laevis oocytes and Flp-In T-REx-HeLa cells providing evidence regarding a possible OATP5A1 function. SLCO5A1 is highly expressed in mature dendritic cells compared to immature dendritic cells (∼6.5-fold) and SLCO5A1 expression correlates with the differentiation status of primary blood cells. A core- and complex- N-glycosylated polypeptide monomer of ∼105 kDa and ∼130 kDa could be localized in intracellular membranes and on the plasma membrane, respectively. Inducible expression of SLCO5A1 in HeLa cells led to an inhibitory effect of ∼20% after 96 h on cell proliferation. Gene expression profiling with these cells identified immunologically relevant genes (e.g. CCL20) and genes implicated in developmental processes (e.g. TGM2). A single nucleotide polymorphism leading to the exchange of amino acid 33 (L→F) revealed no differences regarding protein expression and function. In conclusion, we provide evidence that OATP5A1 might be a non-classical OATP family member which is involved in biological processes that require the reorganization of the cell shape, such as differentiation and migration. PMID:24376674

Dendritic Cell-Based Vaccines that Utilize Myeloid Rather than Plasmacytoid Cells Offer a Superior Survival Advantage in Malignant Glioma.

PubMed

Dey, Mahua; Chang, Alan L; Miska, Jason; Wainwright, Derek A; Ahmed, Atique U; Balyasnikova, Irina V; Pytel, Peter; Han, Yu; Tobias, Alex; Zhang, Lingjiao; Qiao, Jian; Lesniak, Maciej S

2015-07-01

Dendritic cells (DCs) are professional APCs that are traditionally divided into two distinct subsets, myeloid DC (mDCs) and plasmacytoid DC (pDCs). pDCs are known for their ability to secrete large amounts of IFN-α. Apart from IFN-α production, pDCs can also process Ag and induce T cell immunity or tolerance. In several solid tumors, pDCs have been shown to play a critical role in promoting tumor immunosuppression. We investigated the role of pDCs in the process of glioma progression in the syngeneic murine model of glioma. We show that glioma-infiltrating pDCs are the major APC in glioma and are deficient in IFN-α secretion (p < 0.05). pDC depletion leads to increased survival of the mice bearing intracranial tumor by decreasing the number of regulatory T cells (Tregs) and by decreasing the suppressive capabilities of Tregs. We subsequently compared the ability of mDCs and pDCs to generate effective antiglioma immunity in a GL261-OVA mouse model of glioma. Our data suggest that mature pDCs and mDCs isolated from naive mice can be effectively activated and loaded with SIINFEKL Ag in vitro. Upon intradermal injection in the hindleg, a fraction of both types of DCs migrate to the brain and lymph nodes. Compared to mice vaccinated with pDC or control mice, mice vaccinated with mDCs generate a robust Th1 type immune response, characterized by high frequency of CD4(+)T-bet(+) T cells and CD8(+)SIINFEKEL(+) T cells. This robust antitumor T cell response results in tumor eradication and long-term survival in 60% of the animals (p < 0.001). Copyright © 2015 by The American Association of Immunologists, Inc.

Pore-formation by adenylate cyclase toxoid activates dendritic cells to prime CD8+ and CD4+ T cells.

PubMed

Svedova, Martina; Masin, Jiri; Fiser, Radovan; Cerny, Ondrej; Tomala, Jakub; Freudenberg, Marina; Tuckova, Ludmila; Kovar, Marek; Dadaglio, Gilles; Adkins, Irena; Sebo, Peter

2016-04-01

The adenylate cyclase toxin-hemolysin (CyaA) of Bordetella pertussis is a bi-functional leukotoxin. It penetrates myeloid phagocytes expressing the complement receptor 3 and delivers into their cytosol its N-terminal adenylate cyclase enzyme domain (~400 residues). In parallel, ~1300 residue-long RTX hemolysin moiety of CyaA forms cation-selective pores and permeabilizes target cell membrane for efflux of cytosolic potassium ions. The non-enzymatic CyaA-AC(-) toxoid, has repeatedly been successfully exploited as an antigen delivery tool for stimulation of adaptive T-cell immune responses. We show that the pore-forming activity confers on the CyaA-AC(-) toxoid a capacity to trigger Toll-like receptor and inflammasome signaling-independent maturation of CD11b-expressing dendritic cells (DC). The DC maturation-inducing potency of mutant toxoid variants in vitro reflected their specifically enhanced or reduced pore-forming activity and K(+) efflux. The toxoid-induced in vitro phenotypic maturation of DC involved the activity of mitogen activated protein kinases p38 and JNK and comprised increased expression of maturation markers, interleukin 6, chemokines KC and LIX and granulocyte-colony-stimulating factor secretion, prostaglandin E2 production and enhancement of chemotactic migration of DC. Moreover, i.v. injected toxoids induced maturation of splenic DC in function of their cell-permeabilizing capacity. Similarly, the capacity of DC to stimulate CD8(+) and CD4(+) T-cell responses in vitro and in vivo was dependent on the pore-forming activity of CyaA-AC(-). This reveals a novel self-adjuvanting capacity of the CyaA-AC(-) toxoid that is currently under clinical evaluation as a tool for delivery of immunotherapeutic anti-cancer CD8(+) T-cell vaccines into DC.

p15Ink4b is Key in Dendritic Cell Development | Center for Cancer Research

Cancer.gov

An important step in the initiation of leukemia is the ability of pre-leukemic and leukemic cells to evade the immune system. Dendritic cells are instrumental in maintaining the body’s immunity, and CCR scientists have shown for the first time that the tumor suppressor protein p15Ink4b regulates the differentiation and maturation of conventional dendritic cells.

Specific skin lesions in chronic myelomonocytic leukemia: a spectrum of myelomonocytic and dendritic cell proliferations: a study of 42 cases.

PubMed

Vitte, Franck; Fabiani, Bettina; Bénet, Claire; Dalac, Sophie; Balme, Brigitte; Delattre, Claire; Vergier, Béatrice; Beylot-Barry, Marie; Vignon-Pennamen, Dominique; Ortonne, Nicolas; Algros, Marie Paule; Carlotti, Agnès; Samaleire, Dimitri; Frouin, Eric; Levy, Anne; Laroche, Liliane; Theate, Ivan; Monnien, Franck; Mugneret, Francine; Petrella, Tony

2012-09-01

Chronic myelomonocytic leukemia (CMML) is a rare clonal hematopoietic disorder that can also involve the skin. The histopathology of these skin lesions is not clearly defined, and few data are available in the literature. To better understand tumoral skin involvements in CMML we carried out an extensive, retrospective clinicopathologic study of 42 cases selected from the database of the French Study Group of Cutaneous Lymphomas. On the basis of clinical data, morphology, and phenotype we identified 4 clinicopathologic profiles representing 4 distinct groups. The first group comprised myelomonocytic cell tumors (n=18), exhibiting a proliferation of granulocytic or monocytic blast cells, which were CD68 and/or MPO positive but negative for dendritic cell markers. The second group comprised mature plasmacytoid dendritic cell tumors (n=16), denoted by a proliferation of mature plasmacytoid dendritic cells, which were CD123, TCL1, and CD303 positive but CD56, CD1a, and S100 negative. The third group comprised blastic plasmacytoid dendritic cell tumors (n=4), characterized by a proliferation of monomorphous medium-sized blast cells, which were CD4, CD56, CD123, TCL1 positive but CD1a and S100 negative. The fourth group consisted of a putatively novel category of tumor that we named blastic indeterminate dendritic cell tumors (n=4), distinguished by a proliferation of large blast cells that not only exhibited monocytic markers but also the dendritic markers CD1a and S100. These 4 groups showed distinctive outcomes. Finally, we showed, by fluorescence in situ hybridization analysis, a clonal link between bone marrow disease and skin lesions in 4 patients. Herein, we have described a novel scheme for pathologists and physicians to handle specific lesions in CMML, which correspond to a spectrum of myelomonocytic and dendritic cell proliferations with different outcomes. A minimal panel of immunohistochemical markers including CD68, CD1a, S100, Langerin, and CD123 is necessary to make the correct classification in this spectrum of cutaneous CMML tumors, in which dendritic cell lineage plays an important role.

Nucleotides induce chemotaxis and actin polymerization in immature but not mature human dendritic cells via activation of pertussis toxin-sensitive P2y receptors.

PubMed

Idzko, Marco; Dichmann, Stefan; Ferrari, Davide; Di Virgilio, Francesco; la Sala, Andrea; Girolomoni, Giampiero; Panther, Elisabeth; Norgauer, Johannes

2002-08-01

Dendritic cells (DCs) are considered the principal initiators of immune response because of their ability to migrate into peripheral tissues and lymphoid organs, process antigens, and activate naive T cells. There is evidence that extracellular nucleotides regulate certain functions of DCs via G-protein-coupled P2Y receptors (P2YR) and ion-channel-gated P2X receptors (P2XR). Here we investigated the chemotactic activity and analyzed the migration-associated intracellular signaling events such as actin reorganization and Ca(++) transients induced by common P2R agonists such as adenosine 5'-triphosphate (ATP) and 2-methylthioadenosine triphosphate, the P2YR agonists UTP and adenosine 5'-diphosphate (ADP), or the P2XR agonists alphabeta-methylenadenosine-5'-triphosphate and 2',3'-(4-benzoyl)benzoyl-ATP. The common P2R agonists and the selective P2YR agonists turned out to be potent chemotactic stimuli for immature DCs, but not for mature DCs. In contrast, P2XR agonists had only marginal chemotactic activity in both DC types. Chemotaxis was paralleled by a rise in the intracellular Ca(++) concentration and by actin polymerization. Studies with pertussis toxin implicated that intracellular signaling events such as actin polymerization, mobilization of intracellular Ca(++), and migration induced by nucleotides was mediated via G(i/o) protein-coupled P2YR. Moreover, functional studies revealed selective down-regulation of this G(i/o) protein-coupled chemotactic P2YR responsiveness during maturation, although immature and mature DCs expressed similar amounts of mRNA for the P2R subtypes (P2Y(2)R, P2Y(4)R, P2Y(5)R, P2Y(7)R, P2Y(11)R and P2X(1)R, P2X(4)R, P2X(7)R), and no major differences in respect to the mRNA expression of these receptors could be observed by semiquantitative reverse transcription and polymerase chain reaction (RT-PCR). In summary, our data describe a differential chemotactic response of immature and mature DCs to nucleotides, and lend further support to the hypothesis that P2R are a novel class of immunomodulatory plasma membrane receptors suitable for pharmacological intervention.

Engineering intranasal mRNA vaccines to enhance lymph node trafficking and immune responses.

PubMed

Li, Man; Li, You; Peng, Ke; Wang, Ying; Gong, Tao; Zhang, Zhirong; He, Qin; Sun, Xun

2017-12-01

Intranasal mRNA vaccination provides immediate immune protection against pandemic diseases. Recent studies have shown that diverse forms of polyethyleneimine (PEI) have potent mucosal adjuvant activity, which could significantly facilitate the delivery of intranasal mRNA vaccines. Nevertheless, optimizing the chemical structure of PEI to maximize its adjuvanticity and decrease its toxicity remains a challenge. Here we show that the chemical structure of PEI strongly influences how well nanocomplexes of PEI and mRNA migrate to the lymph nodes and elicit immune responses. Conjugating cyclodextrin (CD) with PEI600 or PEI2k yielded CP (CD-PEI) polymers with different CD/PEI ratios. We analyzed the delivery efficacy of CP600, CP2k, and PEI25k as intranasal mRNA vaccine carriers by evaluating the lymph nodes migration and immune responses. Among these polymers, CP2k/mRNA showed significantly higher in vitro transfection efficiency, stronger abilities to migrate to lymph nodes and stimulate dendritic cells maturation in vivo, which further led to potent humoral and cellular immune responses, and showed lower local and systemic toxicity than PEI25k/mRNA. These results demonstrate the potential of CD-PEI2k/mRNA nanocomplex as a self-adjuvanting vaccine delivery vehicle that traffics to lymph nodes with high efficiency. As we face outbreaks of pandemic diseases such as Zika virus, intranasal mRNA vaccination provides instant massive protection against highly variant viruses. Various polymer-based delivery systems have been successfully applied in intranasal vaccine delivery. However, the influence of molecular structure of the polymeric carriers on the lymph node trafficking and dendritic cell maturation is seldom studied for intranasal vaccination. Therefore, engineering polymer-based vaccine delivery system and elucidating the relationship between molecular structure and the intranasal delivery efficiency are essential for maximizing the immune responses. We hereby construct self-adjuvanting polymer-based intranasal mRNA vaccines to enhance lymph node trafficking and further improve immune responses. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Modulation of Dendritic Cell Activation and Subsequent Th1 Cell Polarization by Lidocaine

PubMed Central

Chung, Yeonseok

2015-01-01

Dendritic cells play an essential role in bridging innate and adaptive immunity by recognizing cellular stress including pathogen- and damage-associated molecular patterns and by shaping the types of antigen-specific T cell immunity. Although lidocaine is widely used in clinical settings that trigger cellular stress, it remains unclear whether such treatment impacts the activation of innate immune cells and subsequent differentiation of T cells. Here we showed that lidocaine inhibited the production of IL–6, TNFα and IL–12 from dendritic cells in response to toll-like receptor ligands including lipopolysaccharide, poly(I:C) and R837 in a dose-dependent manner. Notably, the differentiation of Th1 cells was significantly suppressed by the addition of lidocaine while the same treatment had little effect on the differentiation of Th17, Th2 and regulatory T cells in vitro. Moreover, lidocaine suppressed the ovalbumin-specific Th1 cell responses in vivo induced by the adoptive transfer of ovalbumin-pulsed dendritic cells. These results demonstrate that lidocaine inhibits the activation of dendritic cells in response to toll-like receptor signals and subsequently suppresses the differentiation of Th1 cell responses. PMID:26445366

A high-throughput microparticle microarray platform for dendritic cell-targeting vaccines.

PubMed

Acharya, Abhinav P; Clare-Salzler, Michael J; Keselowsky, Benjamin G

2009-09-01

Immunogenomic approaches combined with advances in adjuvant immunology are guiding progress toward rational design of vaccines. Furthermore, drug delivery platforms (e.g., synthetic particles) are demonstrating promise for increasing vaccine efficacy. Currently there are scores of known antigenic epitopes and adjuvants, and numerous synthetic delivery systems accessible for formulation of vaccines for various applications. However, the lack of an efficient means to test immune cell responses to the abundant combinations available represents a significant blockade on the development of new vaccines. In order to overcome this barrier, we report fabrication of a new class of microarray consisting of antigen/adjuvant-loadable poly(D,L lactide-co-glycolide) microparticles (PLGA MPs), identified as a promising carrier for immunotherapeutics, which are co-localized with dendritic cells (DCs), key regulators of the immune system and prime targets for vaccines. The intention is to utilize this high-throughput platform to optimize particle-based vaccines designed to target DCs in vivo for immune system-related disorders, such as autoimmune diseases, cancer and infection. Fabrication of DC/MP arrays leverages the use of standard contact printing miniarraying equipment in conjunction with surface modification to achieve co-localization of particles/cells on isolated islands while providing background non-adhesive surfaces to prevent off-island cell migration. We optimized MP overspotting pin diameter, accounting for alignment error, to allow construction of large, high-fidelity arrays. Reproducible, quantitative delivery of as few as 16+/-2 MPs per spot was demonstrated and two-component MP dosing arrays were constructed, achieving MP delivery which was independent of formulation, with minimal cross-contamination. Furthermore, quantification of spotted, surface-adsorbed MP degradation was demonstrated, potentially useful for optimizing MP release properties. Finally, we demonstrate DC co-localization with PLGA MPs on isolated islands and that DCs do not migrate between islands for up to 24 h. Using this platform, we intend to analyze modulation of DC function by providing multi-parameter combinatorial cues in the form of proteins, peptides and other immuno-modulatory molecules encapsulated in or tethered on MPs. Critically, the miniaturization attained enables high-throughput investigation of rare cell populations by reducing the requirement for cells and reagents by many-fold, facilitating advances in personalized vaccines which target DCs in vivo.

Dendritic excitation–inhibition balance shapes cerebellar output during motor behaviour

PubMed Central

Jelitai, Marta; Puggioni, Paolo; Ishikawa, Taro; Rinaldi, Arianna; Duguid, Ian

2016-01-01

Feedforward excitatory and inhibitory circuits regulate cerebellar output, but how these circuits interact to shape the somatodendritic excitability of Purkinje cells during motor behaviour remains unresolved. Here we perform dendritic and somatic patch-clamp recordings in vivo combined with optogenetic silencing of interneurons to investigate how dendritic excitation and inhibition generates bidirectional (that is, increased or decreased) Purkinje cell output during self-paced locomotion. We find that granule cells generate a sustained depolarization of Purkinje cell dendrites during movement, which is counterbalanced by variable levels of feedforward inhibition from local interneurons. Subtle differences in the dendritic excitation–inhibition balance generate robust, bidirectional changes in simple spike (SSp) output. Disrupting this balance by selectively silencing molecular layer interneurons results in unidirectional firing rate changes, increased SSp regularity and disrupted locomotor behaviour. Our findings provide a mechanistic understanding of how feedforward excitatory and inhibitory circuits shape Purkinje cell output during motor behaviour. PMID:27976716

Kidney dendritic cells in acute and chronic renal disease.

PubMed

Hochheiser, Katharina; Tittel, André; Kurts, Christian

2011-06-01

Dendritic cells are not only the master regulators of adaptive immunity, but also participate profoundly in innate immune responses. Much has been learned about their basic immunological functions and their roles in various diseases. Comparatively little is still known about their role in renal disease, despite their obvious potential to affect immune responses in the kidney, and immune responses that are directed against renal components. Kidney dendritic cells form an abundant network in the renal tubulointerstitium and constantly survey the environment for signs of injury or infection, in order to alert the immune system to the need to initiate defensive action. Recent studies have identified a role for dendritic cells in several murine models of acute renal injury and chronic nephritis. Here we summarize the current knowledge on the role of kidney dendritic cells that has been obtained from the study of murine models of renal disease. © 2010 The Authors. Journal compilation © 2010 Blackwell Publishing Ltd.

The E3 ligase c-Cbl regulates dendritic cell activation

PubMed Central

Chiou, Shin-Heng; Shahi, Payam; Wagner, Ryan T; Hu, Hongbo; Lapteva, Natalia; Seethammagari, Mamatha; Sun, Shao-Cong; Levitt, Jonathan M; Spencer, David M

2011-01-01

The activation of innate and adaptive immunity is always balanced by inhibitory signalling mechanisms to maintain tissue integrity. We have identified the E3 ligase c-Cbl––known for its roles in regulating lymphocyte signalling––as a modulator of dendritic cell activation. In c-Cbl-deficient dendritic cells, Toll-like receptor-induced expression of proinflammatory factors, such as interleukin-12, is increased, correlating with a greater potency of dendritic-cell-based vaccines against established tumours. This proinflammatory phenotype is accompanied by an increase in nuclear factor (NF)-κB activity. In addition, c-Cbl deficiency reduces both p50 and p105 levels, which have been shown to modulate the stimulatory function of NF-κB. Our data indicate that c-Cbl has a crucial, RING-domain-dependent role in regulating dendritic cell maturation, probably by facilitating the regulatory function of p105 and/or p50. PMID:21799517

Non-equivalent antigen presenting capabilities of dendritic cells and macrophages in generating brain-infiltrating CD8 + T cell responses.

PubMed

Malo, Courtney S; Huggins, Matthew A; Goddery, Emma N; Tolcher, Heather M A; Renner, Danielle N; Jin, Fang; Hansen, Michael J; Pease, Larry R; Pavelko, Kevin D; Johnson, Aaron J

2018-02-12

The contribution of antigen-presenting cell (APC) types in generating CD8 + T cell responses in the central nervous system (CNS) is not fully defined, limiting the development of vaccines and understanding of immune-mediated neuropathology. Here, we generate a transgenic mouse that enables cell-specific deletion of the H-2Kb MHC class I molecule. By deleting H-2K b on dendritic cells and macrophages, we compare the effect of each APC in three distinct models of neuroinflammation: picornavirus infection, experimental cerebral malaria, and a syngeneic glioma. Dendritic cells and macrophages both activate CD8 + T cell responses in response to these CNS immunological challenges. However, the extent to which each of these APCs contributes to CD8 + T cell priming varies. These findings reveal distinct functions for dendritic cells and macrophages in generating CD8 + T cell responses to neurological disease.

The morphology and classification of α ganglion cells in the rat retinae: a fractal analysis study.

PubMed

Jelinek, Herbert F; Ristanović, Dušan; Milošević, Nebojša T

2011-09-30

Rat retinal ganglion cells have been proposed to consist of a varying number of subtypes. Dendritic morphology is an essential aspect of classification and a necessary step toward understanding structure-function relationships of retinal ganglion cells. This study aimed at using a heuristic classification procedure in combination with the box-counting analysis to classify the alpha ganglion cells in the rat retinae based on the dendritic branching pattern and to investigate morphological changes with retinal eccentricity. The cells could be divided into two groups: cells with simple dendritic pattern (box dimension lower than 1.390) and cells with complex dendritic pattern (box dimension higher than 1.390) according to their dendritic branching pattern complexity. Both were further divided into two subtypes due to the stratification within the inner plexiform layer. In the present study we have shown that the alpha rat RCGs can be classified further by their dendritic branching complexity and thus extend those of previous reports that fractal analysis can be successfully used in neuronal classification, particularly that the fractal dimension represents a robust and sensitive tool for the classification of retinal ganglion cells. A hypothesis of possible functional significance of our classification scheme is also discussed. Copyright © 2011 Elsevier B.V. All rights reserved.

A Rare Case of Retroperitoneal Follicular Dendritic Cell Sarcoma Identified by 99mTc-HYNIC-TOC SPECT/CT.

PubMed

Li, Yi; Xu, Xiaoping; Xu, Junyan; Huang, Dan

2018-05-31

Follicular dendritic cell sarcoma is a very rare neoplasm, which is not lymphoma, but originates from a type of immune cells called follicular dendritic cells. We presented a 37-year-old woman who has suffered from obstructive jaundice, weight loss and right upper abdominal pain for 2 months. The contrast CT revealed masses located in the region of pancreatic head and lots of enlarged retroperitoneal lymph nodes, both of which were enhanced on the artery phase of CT images. Meanwhile, Tc-HYNIC-TOC SPECT/CT revealed high activity in the corresponding lesions. After biopsy, the masses were pathologically confirmed as retroperitoneal follicular dendritic cell sarcoma.

Chronic pharmacological blockade of the Na+ /Ca2+ exchanger modulates the growth and development of the Purkinje cell dendritic arbor in mouse cerebellar slice cultures.

PubMed

Sherkhane, Pradeep; Kapfhammer, Josef P

2017-09-01

The Na + /Ca 2+ exchanger (NCX) is a bidirectional plasma membrane antiporter involved in Ca 2+ homeostasis in eukaryotes. NCX has three isoforms, NCX1-3, and all of them are expressed in the cerebellum. Immunostaining on cerebellar slice cultures indicates that NCX is widely expressed in the cerebellum, including expression in Purkinje cells. The pharmacological blockade of the forward mode of NCX (Ca 2+ efflux mode) by bepridil moderately inhibited growth and development of Purkinje cell dendritic arbor in cerebellar slice cultures. However, the blockade of the reverse mode (Ca 2+ influx mode) by KB-R7943 severely reduced the dendritic arbor and induced a morphological change with thickened distal dendrites. The effect of KB-R7943 on dendritic growth was unrelated to the activity of voltage-gated calcium channels and was also apparent in the absence of bioelectrical activity indicating that it was mediated by NCX expressed in Purkinje cells. We have used additional NCX inhibitors including CB-DMB, ORM-10103, SEA0400, YM-244769, and SN-6 which have higher specificity for NCX isoforms and target either the forward, reverse, or both modes. These inhibitors caused a strong dendritic reduction similar to that seen with KB-R7943, but did not elicit thickening of distal dendrites. Our findings indicate that disturbance of the NCX-dependent calcium transport in Purkinje cells induces a reduction of dendritic arbor, which is presumably caused by changes in the calcium handling, and underline the importance of the calcium equilibrium for the dendritic development in cerebellar Purkinje cells. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Properties of a herpes simplex virus multiple immediate-early gene-deleted recombinant as a vaccine vector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watanabe, Daisuke; Brockman, Mark A.; Ndung'u, Thumbi

2007-01-20

Herpes simplex virus (HSV) recombinants induce durable immune responses in rhesus macaques and mice and have induced partial protection in rhesus macaques against mucosal challenge with virulent simian immunodeficiency virus (SIV). In this study, we evaluated the properties of a new generation HSV vaccine vector, an HSV-1 multiple immediate-early (IE) gene deletion mutant virus, d106, which contains deletions in the ICP4, ICP27, ICP22, and ICP47 genes. Because several of the HSV IE genes have been implicated in immune evasion, inactivation of the genes encoding these proteins was expected to result in enhanced immunogenicity. The d106 virus expresses few HSV genemore » products and shows minimal cytopathic effect in cultured cells. When d106 was inoculated into mice, viral DNA accumulated at high levels in draining lymph nodes, consistent with an ability to transduce dendritic cells and activate their maturation and movement to lymph nodes. A d106 recombinant expressing Escherichia coli {beta}-galactosidase induced durable {beta}-gal-specific IgG and CD8{sup +} T cell responses in naive and HSV-immune mice. Finally, d106-based recombinants have been constructed that express simian immunodeficiency virus (SIV) gag, env, or a rev-tat-nef fusion protein for several days in cultured cells. Thus, d106 shows many of the properties desirable in a vaccine vector: limited expression of HSV gene products and cytopathogenicity, high level expression of transgenes, ability to induce durable immune responses, and an ability to transduce dendritic cells and induce their maturation and migration to lymph nodes.« less

[Thyroid hormones and the development of the nervous system].

PubMed

Mussa, G C; Zaffaroni, M; Mussa, F

1990-09-01

The growth and differentiation of the central nervous system are closely related to the presence of iodine and thyroid hormones. During the first trimester of human pregnancy the development of the nervous system depends entirely on the availability of iodine; after 12 week of pregnancy it depends on the initial secretion of iodothyronine by the fetal thyroid gland. During the early stages of the development of the nervous system a thyroid hormone deficit may provoke alterations in the maturation of both noble nervous cells (cortical pyramidal cells, Purkinje cells) and glial cells. Hypothyroidism may lead to cellular hypoplasia and reduced dendritic ramification, gemmules and interneuronal connections. Experimental studies in hypothyroid rats have also shown alterations in the content and organization of neuronal intracytoplasmatic microtubules, the biochemical maturation of synaptosomes and the maturation of nuclear and cytoplasmatic T3 receptors. Excess thyroid hormones during the early stages of development may also cause permanent damage to the central nervous system. Hyperthyroidism may initially induce an acceleration of the maturation processes, including the migration and differentiation of cells, the extension of the dendritic processes and synaptogenesis. An excess of thyroid hormones therefore causes neuronal proliferation to end precociously leading to a reduction of the total number of gemmules. Experimental research and clinical studies have partially clarified the correlation between the maturation of the nervous system and thyroid function during the early stages of development; both a deficit and excess of thyroid hormones may lead to permanent anatomo-functional damage to the central nervous system.(ABSTRACT TRUNCATED AT 250 WORDS)

Saccharomyces boulardii inhibits lipopolysaccharide-induced activation of human dendritic cells and T cell proliferation

PubMed Central

Thomas, S; Przesdzing, I; Metzke, D; Schmitz, J; Radbruch, A; Baumgart, D C

2009-01-01

Saccharomyces boulardii (Sb) is a probiotic yeast preparation that has demonstrated efficacy in inflammatory and infectious disorders of the gastrointestinal tract in controlled clinical trials. Although patients clearly benefit from treatment with Sb, little is known on how Sb unfolds its anti-inflammatory properties in humans. Dendritic cells (DC) balance tolerance and immunity and are involved critically in the control of T cell activation. Thus, they are believed to have a pivotal role in the initiation and perpetuation of chronic inflammatory disorders, not only in the gut. We therefore decided to investigate if Sb modulates DC function. Culture of primary (native, non-monocyte-derived) human myeloid CD1c+CD11c+CD123– DC (mDC) in the presence of Sb culture supernatant (active component molecular weight < 3 kDa, as evaluated by membrane partition chromatography) reduced significantly expression of the co-stimulatory molecules CD40 and CD80 (P < 0·01) and the DC mobilization marker CC-chemokine receptor CCR7 (CD197) (P < 0·001) induced by the prototypical microbial antigen lipopolysaccharide (LPS). Moreover, secretion of key proinflammatory cytokines such as tumour necrosis factor-α and interleukin (IL)-6 were notably reduced, while the secretion of anti-inflammatory IL-10 increased. Finally, Sb supernatant inhibited the proliferation of naive T cells in a mixed lymphocyte reaction with mDC. In summary, our data suggest that Sb may exhibit part of its anti-inflammatory potential through modulation of DC phenotype, function and migration by inhibition of their immune response to bacterial microbial surrogate antigens such as LPS. PMID:19161443

[Quantitative analysis of the structure of neuronal dendritic spines in the striatum using the Leitz-ASM system].

PubMed

Leontovich, T A; Zvegintseva, E G

1985-10-01

Two principal classes of striatum long axonal neurons (sparsely ramified reticular cells and densely ramified dendritic cells) were analyzed quantitatively in four animal species: hedgehog, rabbit, dog and monkey. The cross section area, total dendritic length and the area of dendritic field were measured using "LEITZ-ASM" system. Classes of neurons studied were significantly different in dogs and monkeys, while no differences were noted between hedgehog and rabbit. Reticular neurons of different species varied much more than dendritic ones. Quantitative analysis has revealed the progressive increase in the complexity of dendritic tree in mammals from rabbit to monkey.

pDC therapy induces recovery from EAE by recruiting endogenous pDC to sites of CNS inflammation

PubMed Central

Duraes, Fernanda V.; Lippens, Carla; Steinbach, Karin; Dubrot, Juan; Brighouse, Dale; Bendriss-Vermare, Nathalie; Issazadeh-Navikas, Shohreh; Merkler, Doron; Hugues, Stephanie

2016-01-01

Plasmacytoid dendritic cells (pDCs) exhibit both innate and adaptive functions. In particular they are the main source of type I IFNs and directly impact T cell responses through antigen presentation. We have previously demonstrated that during experimental autoimmune encephalomyelitis (EAE) initiation, myelin-antigen presentation by pDCs is associated with suppressive Treg development and results in attenuated EAE. Here, we show that pDCs transferred during acute disease phase confer recovery from EAE. Clinical improvement is associated with migration of injected pDCs into inflamed CNS and is dependent on the subsequent and selective chemerin-mediated recruitment of endogenous pDCs to the CNS. The protective effect requires pDC pre-loading with myelin antigen, and is associated with the modulation of CNS-infiltrating pDC phenotype and inhibition of CNS encephalitogenic T cells. This study may pave the way for novel pDC-based cell therapies in autoimmune diseases, aiming at specifically modulating pathogenic cells that induce and sustain autoimmune inflammation. PMID:26341385

The VEGF-Receptor Inhibitor Axitinib Impairs Dendritic Cell Phenotype and Function

PubMed Central

Daecke, Solveig Nora; Riethausen, Kati; Kotthoff, Philipp; Flores, Chrystel; Kurts, Christian; Brossart, Peter

2015-01-01

Inhibitors of VEGF receptor (VEGFR) signaling such as sorafenib and sunitinib that are currently used in the treatment of malignant diseases have been shown to affect immunological responses by inhibition of the function of antigen presenting cells and T lymphocytes. The VEGFR-inhibitor axitinib has recently been approved for second line therapy of metastatic renal cell carcinoma. While there is some evidence that axitinib might interfere with the activation of T cells, not much is known about the effects of axitinib on dendritic cell (DC) phenotype and function. We here show that the addition of axitinib during the final Toll-like receptor-4-induced maturation step of monocyte-derived human DCs results in a reduced DC activation characterized by impaired expression of activation markers and co-stimulatory molecules such as CD80, CD83 and CD86. We further found a decreased secretion of interleukin-12 which was accompanied by reduced nuclear expression of the transcription factor cRel. In addition, we found a dose-dependent reduced activation of p38 and STAT3 in axitinib-exposed DCs, whereas the expression was not affected. The dysfunction of axitinib-exposed DCs was further underlined by their impaired induction of allogeneic T cell proliferation in a mixed lymphocyte reaction assay and inhibition of DC migration. Our results demonstrate that axitinib significantly affects DC differentiation and function primarily via the inhibition of the nuclear factor kappa B signaling pathway leading to impaired T cell activation. This will be of importance for the design of future vaccination protocols and therapeutic approaches aiming at combining different treatment strategies, eg such as programmed death-1 inhibitors with axitinib. PMID:26042424

Sphingosine-1-phosphate receptor-1 (S1P1) is expressed by lymphocytes, dendritic cells, and endothelium and modulated during inflammatory bowel disease.

PubMed

Karuppuchamy, T; Behrens, E-H; González-Cabrera, P; Sarkisyan, G; Gima, L; Boyer, J D; Bamias, G; Jedlicka, P; Veny, M; Clark, D; Peach, R; Scott, F; Rosen, H; Rivera-Nieves, J

2017-01-01

The sphingosine-1-phosphate receptor-1 (S1P 1 ) agonist ozanimod ameliorates ulcerative colitis, yet its mechanism of action is unknown. Here, we examine the cell subsets that express S1P 1 in intestine using S1P 1 -eGFP mice, the regulation of S1P 1 expression in lymphocytes after administration of dextran sulfate sodium (DSS), after colitis induced by transfer of CD4 + CD45RB hi cells, and by crossing a mouse with TNF-driven ileitis with S1P 1 -eGFP mice. We then assayed the expression of enzymes that regulate intestinal S1P levels, and the effect of FTY720 on lymphocyte behavior and S1P 1 expression. We found that not only T and B cells express S1P 1 , but also dendritic (DC) and endothelial cells. Furthermore, chronic but not acute inflammatory signals increased S1P 1 expression, while the enzymes that control tissue S1P levels in mice and humans with inflammatory bowel disease (IBD) were uniformly dysregulated, favoring synthesis over degradation. Finally, we observed that FTY720 reduced T-cell velocity and induced S1P 1 degradation and retention of Naïve but not effector T cells. Our data demonstrate that chronic inflammation modulates S1P 1 expression and tissue S1P levels and suggests that the anti-inflammatory properties of S1PR agonists might not be solely due to their lymphopenic effects, but also due to potential effects on DC migration and vascular barrier function.

Identification and Characterization of a Dendritic Cell Precursor in Parenchymal Lung Tissue.

PubMed

von Garnier, Christophe; Blank, Fabian; Rothen-Rutishauser, Barbara; Goethert, Joachim R; Holt, Patrick G; Stumbles, Philip A; Strickland, Deborah H

2017-03-01

The pulmonary parenchymal and mucosal microenvironments are constantly exposed to the external environment and thus require continuous surveillance to maintain steady-state immunological homeostasis. This is achieved by a mobile network of pulmonary dendritic cells (DC) and macrophages (mø) that constantly sample and process microenvironmental antigens into signals that can initiate or dampen inflammation, either locally or after onward migration to draining lymph nodes. The constant steady-state turnover of pulmonary DC and mø requires replenishment from bone marrow precursors; however, the nature of the pulmonary precursor cell (PC) remains unclear, although recent studies suggest that subsets of pulmonary DC may derive from circulating monocytic precursors. In the current study, we describe a population of cells in steady-state mouse lung tissue that has the surface phenotypic and ultrastructural characteristics of a common DC progenitor. Irradiation and reconstitution studies confirmed the bone marrow origins of this PC and showed that it had rapid depletion and reconstitution kinetics that were similar to those of DC, with a 50% repopulation by donor-derived cells by Days 7-9 after reconstitution. This was significantly faster than the rates observed for mø, which showed 50% repopulation by donor-derived cells beyond Days 16-21 after reconstitution. Purified PC gained antigen-presenting function and a cell surface phenotype similar to that of pulmonary DC after maturation in vitro, with light and electron microscopy confirming a myeloid DC morphology. To the best of our knowledge, this is the first study to describe a PC for DC in lung tissue; the findings have implications for the restoration of pulmonary immunological homeostasis after bone marrow transplant.

Lung dendritic cells are stimulated by ultrafine particles and play a key role in particle adjuvant activity.

PubMed

de Haar, Colin; Kool, Mirjam; Hassing, Ine; Bol, Marianne; Lambrecht, Bart N; Pieters, Raymond

2008-05-01

The adjuvant activity of air pollution particles on allergic airway sensitization is well known, but the cellular mechanisms underlying this adjuvant potential are not clear. We sough to study the role of dendritic cells and the costimulatory molecules CD80 and CD86 in the adjuvant activity of ultrafine carbon black particles (CBP). The proliferation of CFSE-labeled DO11.10 CD4 cells was studied after intranasal exposure to particles and ovalbumin (OVA). Next the frequency of myeloid dendritic cells (mDCs) and plasmacytoid dendritic cells and their expression of CD80 and CD86 were studied in the peribronchial lymph nodes (PBLNs). The expression of costimulatory molecules was also studied on bone marrow-derived mDCs after exposure to CBPs in vitro, and the importance of costimulation in CBP adjuvant activity was assessed by using CD80/CD86-deficient mice or cytotoxic T lymphocyte-associated antigen 4 (CTLA4)-Ig in vivo. Our data show that CBPs plus OVA caused proliferation of DO11.10 CD4 cells and high levels of cytokine production in the PBLNs. Furthermore, the combined CBP plus OVA exposure increased the number of mDCs and expression of costimulatory molecules in the PBLNs. In addition, CBPs upregulated the expression of CD80/CD86 molecules on dendritic cells in vitro, which are necessary for the particle adjuvant effects in vivo. Together this study shows the importance of dendritic cells and costimulation in particle adjuvant activity. Furthermore, we show for the first time that CBPs can also directly induce maturation of dendritic cells.

Dendritic branching angles of pyramidal cells across layers of the juvenile rat somatosensory cortex.

PubMed

Leguey, Ignacio; Bielza, Concha; Larrañaga, Pedro; Kastanauskaite, Asta; Rojo, Concepción; Benavides-Piccione, Ruth; DeFelipe, Javier

2016-09-01

The characterization of the structural design of cortical microcircuits is essential for understanding how they contribute to function in both health and disease. Since pyramidal neurons represent the most abundant neuronal type and their dendritic spines constitute the major postsynaptic elements of cortical excitatory synapses, our understanding of the synaptic organization of the neocortex largely depends on the available knowledge regarding the structure of pyramidal cells. Previous studies have identified several apparently common rules in dendritic geometry. We study the dendritic branching angles of pyramidal cells across layers to further shed light on the principles that determine the geometric shapes of these cells. We find that the dendritic branching angles of pyramidal cells from layers II-VI of the juvenile rat somatosensory cortex suggest common design principles, despite the particular morphological and functional features that are characteristic of pyramidal cells in each cortical layer. J. Comp. Neurol. 524:2567-2576, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

An outsider's perspective--ecotaxis revisited: an integrative review of cancer environment, iron and immune system cells.

PubMed

de Sousa, Maria

2011-04-01

Lymphoid cell and tumor cell migration share similarities: 1. migration to specific microenvironments; 2. increased microvasculature with increased growth; 3. cell division. At the same time, contrasting aspects between the two merit attention: 1. failure of tumors to return to microvasculature quiescence; 2. failure of malignant cells to stop dividing; 3. failure of tumor cells to re-enter the circulation after returning to a non-activated phenotype. Analysis of these contrasting aspects leads to the reviewing of unexpected roles of immune cells in the tumor environment, recent work on ferroportin expression with lack of iron export by tumor cells, iron export by M2 macrophages, and deficient dendritic cells (DCs) in the tumor environment. DCs in lymph nodes have recently been found to bring lymph node vasculature to quiescence after antigen stimulation. Contrary to current dogma, the evidence is that some immune system cells in the tumor environment may be favoring regulators instead of diminishing tumor growth. In addition, recent data herein reviewed will make it difficult not to consider iron and iron gene expression as relevant components of the tumor environment. Finally, I conclude with wondering how much longer what I call the 'Hunter Paradigm' will dominate cancer research and immunology and how timely it is to acknowledge in the first decade of a new century, Mina Bissell as a pioneer in the change of that paradigm in Cancer Research. "Suppose he'd listened to the erudite committee; He would have only found where not to look" WH Auden.

Tumor cell apoptosis induces tumor-specific immunity in a CC chemokine receptor 1- and 5-dependent manner in mice.

PubMed

Iida, Noriho; Nakamoto, Yasunari; Baba, Tomohisa; Kakinoki, Kaheita; Li, Ying-Yi; Wu, Yu; Matsushima, Kouji; Kaneko, Shuichi; Mukaida, Naofumi

2008-10-01

The first step in the generation of tumor immunity is the migration of dendritic cells (DCs) to the apoptotic tumor, which is presumed to be mediated by various chemokines. To clarify the roles of chemokines, we induced apoptosis using suicide gene therapy and investigated the immune responses following tumor apoptosis. We injected mice with a murine hepatoma cell line, BNL 1ME A.7R.1 (BNL), transfected with HSV-thymidine kinase (tk) gene and then treated the animals with ganciclovir (GCV). GCV treatment induced massive tumor cell apoptosis accompanied with intratumoral DC infiltration. Tumor-infiltrating DCs expressed chemokine receptors CCR1 and CCR5, and T cells and macrophages expressed CCL3, a ligand for CCR1 and CCR5. Moreover, tumor apoptosis increased the numbers of DCs migrating into the draining lymph nodes and eventually generated a specific cytotoxic cell population against BNL cells. Although GCV completely eradicated HSV-tk-transfected BNL cells in CCR1-, CCR5-, or CCL3-deficient mice, intratumoral and intranodal DC infiltration and the subsequent cytotoxicity generation were attenuated in these mice. When parental cells were injected again after complete eradication of primary tumors by GCV treatment, the wild-type mice completely rejected the rechallenged cells, but the deficient mice exhibited impairment in rejection. Thus, we provide definitive evidence indicating that CCR1 and CCR5 and their ligand CCL3 play a crucial role in the regulation of intratumoral DC accumulation and the subsequent establishment of tumor immunity following induction of tumor apoptosis by suicide genes.

Calcium transient prevalence across the dendritic arbour predicts place field properties.

PubMed

Sheffield, Mark E J; Dombeck, Daniel A

2015-01-08

Establishing the hippocampal cellular ensemble that represents an animal's environment involves the emergence and disappearance of place fields in specific CA1 pyramidal neurons, and the acquisition of different spatial firing properties across the active population. While such firing flexibility and diversity have been linked to spatial memory, attention and task performance, the cellular and network origin of these place cell features is unknown. Basic integrate-and-fire models of place firing propose that such features result solely from varying inputs to place cells, but recent studies suggest instead that place cells themselves may play an active role through regenerative dendritic events. However, owing to the difficulty of performing functional recordings from place cell dendrites, no direct evidence of regenerative dendritic events exists, leaving any possible connection to place coding unknown. Using multi-plane two-photon calcium imaging of CA1 place cell somata, axons and dendrites in mice navigating a virtual environment, here we show that regenerative dendritic events do exist in place cells of behaving mice, and, surprisingly, their prevalence throughout the arbour is highly spatiotemporally variable. Furthermore, we show that the prevalence of such events predicts the spatial precision and persistence or disappearance of place fields. This suggests that the dynamics of spiking throughout the dendritic arbour may play a key role in forming the hippocampal representation of space.

Calcium transient prevalence across the dendritic arbor predicts place field properties

PubMed Central

Sheffield, Mark E. J.; Dombeck, Daniel A.

2014-01-01

Establishing the hippocampal cellular ensemble that represents an animal’s environment involves the emergence and disappearance of place fields in specific CA1 pyramidal neurons1–4, and the acquisition of different spatial firing properties across the active population5. While such firing flexibility and diversity have been linked to spatial memory, attention and task performance6,7, the cellular and network origin of these place cell features is unknown. Basic integrate-and-fire models of place firing propose that such features result solely from varying inputs to place cells8,9, but recent studies3,10 instead suggest that place cells themselves may play an active role through regenerative dendritic events. However, due to the difficulty of performing functional recordings from place cell dendrites, no direct evidence of regenerative dendritic events exists, leaving any possible connection to place coding unknown. Using multi-plane two-photon calcium imaging of CA1 place cell somata, axons, and dendrites in mice navigating a virtual environment, we show that regenerative dendritic events do exist in place cells of behaving mice and, surprisingly, their prevalence throughout the arbor is highly spatiotemporally variable. Further, we show that the prevalence of such events predicts the spatial precision and persistence or disappearance of place fields. This suggests that the dynamics of spiking throughout the dendritic arbor may play a key role in forming the hippocampal representation of space. PMID:25363782

Morphological characterization of rat entorhinal neurons in vivo: soma-dendritic structure and axonal domains.

PubMed

Lingenhöhl, K; Finch, D M

1991-01-01

We used in vivo intracellular labeling with horseradish peroxidase in order to study the soma-dendritic morphology and axonal projections of rat entorhinal neurons. The cells responded to hippocampal stimulation with inhibitory postsynaptic potentials, and thus likely received direct or indirect hippocampal input. All cells (n = 24) showed extensive dendritic domains that extended in some cases for more than 1 mm. The dendrites of layer II neurons were largely restricted to layers I and II or layers I-III, while the dendrites of deeper cells could extend through all cortical layers. Computed 3D rotations showed that the basilar dendrites of deep pyramids extended roughly parallel to the cortical layering, and that they were mostly confined to the layer containing the soma and layers immediately adjacent. Total dendritic lengths averaged 9.8 mm +/- 3.8 (SD), and ranged from 5 mm to more than 18 mm. Axonal processes could be visualized in 21 cells. Most of these showed axonal branching within the entorhinal cortex, sometimes extensive. Efferent axonal domains were reconstructed in detail in 3 layer II stellate cells. All 3 projected axons across the subicular complex to the dentate gyrus. One of these cells showed an extensive net-like axonal domain that also projected to several other structures, including the hippocampus proper, subicular complex, and the amygdalo-piriform transition area. The axons of layer III and IV cells projected to the angular bundle, where they continued in a rostral direction. In contrast to the layer II, III and IV cells, no efferent axonal branches leaving the entorhinal cortex could be visualized in 5 layer V neurons. The data indicate that entorhinal neurons can integrate input from a considerable volume of entorhinal cortex by virtue of their extensive dendritic domains, and provide a further basis for specifying the layers in which cells receive synaptic input. The extensive axonal branching pattern seen in most of the cells would support divergent propagation of their activity.

Democracy-independence trade-off in oscillating dendrites and its implications for grid cells.

PubMed

Remme, Michiel W H; Lengyel, Máté; Gutkin, Boris S

2010-05-13

Dendritic democracy and independence have been characterized for near-instantaneous processing of synaptic inputs. However, a wide class of neuronal computations requires input integration on long timescales. As a paradigmatic example, entorhinal grid fields have been thought to be generated by the democratic summation of independent dendritic oscillations performing direction-selective path integration. We analyzed how multiple dendritic oscillators embedded in the same neuron integrate inputs separately and determine somatic membrane voltage jointly. We found that the interaction of dendritic oscillations leads to phase locking, which sets an upper limit on the timescale for independent input integration. Factors that increase this timescale also decrease the influence that the dendritic oscillations exert on somatic voltage. In entorhinal stellate cells, interdendritic coupling dominates and causes these cells to act as single oscillators. Our results suggest a fundamental trade-off between local and global processing in dendritic trees integrating ongoing signals. Copyright 2010 Elsevier Inc. All rights reserved.

Golgi-type I and Golgi-type II neurons in the ventral anterior thalamic nucleus of the adult human: morphological features and quantitative analysis.

PubMed

Al-Hussain Bani Hani, Saleh M; El-Dwairi, Qasim A; Bataineh, Ziad M; Al-Haidari, Mohammad S; Al-Alami, Jamil

2008-05-01

The morphological and quantitative features of neurons in the adult human ventral anterior thalamic nucleus were studied in Golgi preparations. Two neuronal types were found and their quantitative features were studied. Golgi-type I neurons were medium to large cells with dense dendritic trees and dendritic protrusions and short hair-like appendages. They have somatic mean diameter of 30.8 microm (+/-9.4, n = 85). They have an average 100.3 dendritic branches, 48.97 dendritic branching points, and 58.85 dendritic tips. The mean diameters of their primary, secondary, and tertiary dendrites were 3.1 microm (+/-1, n = 80), 1.85 microm (+/-0.8, n = 145), and 1.5 microm (+/-0.4, n = 160), respectively. Golgi-type II neurons were small to medium cells with few sparsely branching dendrites and dendritic stalked appendages with or without terminal swellings. They have somatic mean diameters of 22.2 microm (+/-5.8, n = 120). They have an average 33.76 dendritic branches, 16.49 dendritic branching points, and 21.97 dendritic tips. The mean diameters of their primary, secondary, and tertiary dendrites were 1.6 microm (+/-0.86, n = 70), 1.15 microm (+/-0.55, n = 118), and 1 microm (+/-0.70, n = 95), respectively. These quantitative data may form the basis for further quantitative studies involving aging or some degenerative diseases that may affect cell bodies and/or dendritic trees of the Golgi-type I and/or Golgi-type II thalamic neurons.

Hydrocortisone prevents immunosuppression by interleukin-10+ natural killer cells after trauma-hemorrhage.

PubMed

Roquilly, Antoine; Broquet, Alexis; Jacqueline, Cédric; Masson, Damien; Segain, Jean Pierre; Braudeau, Cecile; Vourc'h, Mickael; Caillon, Jocelyne; Altare, Frédéric; Josien, Regis; Retière, Christelle; Villadangos, Jose; Asehnoune, Karim

2014-12-01

Trauma induces a state of immunosuppression, which is responsible for the development of nosocomial infections. Hydrocortisone reduces the rate of pneumonia in patients with trauma. Because alterations of dendritic cells and natural killer cells play a central role in trauma-induced immunosuppression, we investigated whether hydrocortisone modulates the dendritic cell/natural killer cell cross talk in the context of posttraumatic pneumonia. Experimental study. Research laboratory from an university hospital. Bagg Albino/cJ mice (weight, 20-24 g). First, in an a priori substudy of a multicenter, randomized, double-blind, placebo-controlled trial of hydrocortisone (200 mg/d for 7 d) in patients with severe trauma, we have measured the blood levels of five cytokines (tumor necrosis factor-α, interleukin-6, interleukin-10, interleukin-12, interleukin-17) at day 1 and day 8. In a second step, the effects of hydrocortisone on dendritic cell/natural killer cell cross talk were studied in a mouse model of posttraumatic pneumonia. Hydrocortisone (0.6 mg/mice i.p.) was administered immediately after hemorrhage. Twenty-four hours later, the mice were challenged with Staphylococcus aureus (7 × 10 colony-forming units). Using sera collected during a multicenter study in patients with trauma, we found that hydrocortisone decreased the blood level of interleukin-10, a cytokine centrally involved in the regulation of dendritic cell/natural killer cell cluster. In a mouse model of trauma-hemorrhage-induced immunosuppression, splenic natural killer cells induced an interleukin-10-dependent elimination of splenic dendritic cell. Hydrocortisone treatment reduced this suppressive function of natural killer cells and increased survival of mice with posthemorrhage pneumonia. The reduction of the interleukin-10 level in natural killer cells by hydrocortisone was partially dependent on the up-regulation of glucocorticoid-induced tumor necrosis factor receptor-ligand (TNFsf18) on dendritic cell. These data demonstrate that trauma-induced immunosuppression is characterized by an interleukin-10-dependent elimination of dendritic cell by natural killer cells and that hydrocortisone improves outcome by limiting this immunosuppressive feedback loop.

Multivalent glycopeptide dendrimers for the targeted delivery of antigens to dendritic cells.

PubMed

García-Vallejo, Juan J; Ambrosini, Martino; Overbeek, Annemieke; van Riel, Wilhelmina E; Bloem, Karien; Unger, Wendy W J; Chiodo, Fabrizio; Bolscher, Jan G; Nazmi, Kamran; Kalay, Hakan; van Kooyk, Yvette

2013-04-01

Dendritic cells are the most powerful type of antigen presenting cells. Current immunotherapies targeting dendritic cells have shown a relative degree of success but still require further improvement. One of the most important issues to solve is the efficiency of antigen delivery to dendritic cells in order to achieve an appropriate uptake, processing, and presentation to Ag-specific T cells. C-type lectins have shown to be ideal receptors for the targeting of antigens to dendritic cells and allow the use of their natural ligands - glycans - instead of antibodies. Amongst them, dendritic cell-specific ICAM-3-grabbing non-integrin (DC-SIGN) is an interesting candidate due to its biological properties and the availability of its natural carbohydrate ligands. Using Le(b)-conjugated poly(amido amine) (PAMAM) dendrimers we aimed to characterize the optimal level of multivalency necessary to achieve the desired internalization, lysosomal delivery, Ag-specific T cell proliferation, and cytokine response. Increasing DC-SIGN ligand multivalency directly translated in an enhanced binding, which might also be interesting for blocking purposes. Internalization, routing to lysosomal compartments, antigen presentation and cytokine response could be optimally achieved with glycopeptide dendrimers carrying 16-32 glycan units. This report provides the basis for the design of efficient targeting of peptide antigens for the immunotherapy of cancer, autoimmunity and infectious diseases. Copyright © 2012 Elsevier Ltd. All rights reserved.

Dendritic cells cross-present HIV antigens from live as well as apoptotic infected CD4+ T lymphocytes

NASA Astrophysics Data System (ADS)

Marañón, Concepción; Desoutter, Jean-François; Hoeffel, Guillaume; Cohen, William; Hanau, Daniel; Hosmalin, Anne

2004-04-01

A better understanding of the antigen presentation pathways that lead to CD8+ T cell recognition of HIV epitopes in vivo is needed to achieve better immune control of HIV replication. Here, we show that cross-presentation of very small amounts of HIV proteins from apoptotic infected CD4+ T lymphocytes by dendritic cells to CD8+ T cells is much more efficient than other known HIV presentation pathways, i.e., direct presentation of infectious virus or cross-presentation of defective virus. Unexpectedly, dendritic cells also take up actively antigens into endosomes from live infected CD4+ T lymphocytes and cross-present them as efficiently as antigens derived from apoptotic infected cells. Moreover, live infected CD4+ T cells costimulate cross-presenting dendritic cells in the process. Therefore, dendritic cells can present very small amounts of viral proteins from infected T cells either after apoptosis, which is frequent during HIV infection, or not. Thus, if HIV expression is transiently induced while costimulation is enhanced (for instance after IL-2 and IFN immune therapy), this HIV antigen presentation pathway could be exploited to eradicate latently infected reservoirs, which are poorly recognized by patients' immune systems.

[Phenotypes of dendritic cells in central lymph of healthy rabbits and during correction of experimental atherosclerosis].

PubMed

Kuznetsov, A V

1992-09-01

Dendritic cells of central lymph of rabbits have been identified according to the form of the cell body, characteristics of formation and branchiness of its processes in health, in atherosclerosis, its correction with radon, polyphenol preparations made of Sanguisorba officinalis and in combination of the latter. Two main types of dendritic cells have been distinguished. Type I is characterized by a rounded body with clear outlines, protrusions and one compact process. Such cells are often found in lymph of intact animals. Type II has a cell body of various forms with two and more compact or branching processes. This type is mainly detected in atherosclerosis and its correction. The prevalence of the above phenotypes of dendritic cells is attributed to the response of the immune system to atherosclerosis and its correction.

CD22 is required for protection against West Nile virus Infection.

PubMed

Ma, Daphne Y; Suthar, Mehul S; Kasahara, Shinji; Gale, Michael; Clark, Edward A

2013-03-01

West Nile virus (WNV) is a RNA virus of the family Flaviviridae and the leading cause of mosquito-borne encephalitis in the United States. Humoral immunity is essential for protection against WNV infection; however, the requirements for initiating effective antibody responses against WNV infection are still unclear. CD22 (Siglec-2) is expressed on B cells and regulates B cell receptor signaling, cell survival, proliferation, and antibody production. In this study, we investigated how CD22 contributes to protection against WNV infection and found that CD22 knockout (Cd22(-/-)) mice were highly susceptible to WNV infection and had increased viral loads in the serum and central nervous system (CNS) compared to wild-type (WT) mice. This was not due to a defect in humoral immunity, as Cd22(-/-) mice had normal WNV-specific antibody responses. However, Cd22(-/-) mice had decreased WNV-specific CD8(+) T cell responses compared to those of WT mice. These defects were not simply due to reduced cytotoxic activity or increased cell death but, rather, were associated with decreased lymphocyte migration into the draining lymph nodes (dLNs) of infected Cd22(-/-) mice. Cd22(-/-) mice had reduced production of the chemokine CCL3 in the dLNs after infection, suggesting that CD22 affects chemotaxis via controlling chemokine production. CD22 was not restricted to B cells but was also expressed on a subset of splenic DCIR2(+) dendritic cells that rapidly expand early after WNV infection. Thus, CD22 plays an essential role in controlling WNV infection by governing cell migration and CD8(+) T cell responses.

Imaging early pathogenesis of bubonic plague: are neutrophils commandeered for lymphatic transport of bacteria?

PubMed

Bland, David M; Anderson, Deborah M

2013-11-05

Vector-borne infections begin in the dermis when a pathogen is introduced by an arthropod during a blood meal. Several barriers separate an invading pathogen from its replicative niche, including phagocytic cells in the dermis that activate immunity by engulfing would-be pathogens and migrating to the lymph node. In addition, neutrophils circulating in the blood are rapidly recruited when the dermal barriers are penetrated. For flea-borne disease, no insect-encoded immune-suppressive molecules have yet been described that might influence the establishment of infection, leaving the bacteria on their own to defend against the mammalian immune system. Shortly after a flea transmits Yersinia pestis to a mammalian host, the bacteria are transported to the lymph node, where they grow logarithmically and later spread systemically. Even a single cell of Y. pestis can initiate a lethal case of plague. In their article, J. G. Shannon et al. [mBio 4(5):e00170-13, 2013, doi:10.1128/mBio.00170-13] used intravital microscopy to visualize trafficking of Y. pestis in transgenic mice in vivo, which allowed them to examine interactions between bacteria and specific immune cells. Bacteria appeared to preferentially interact with neutrophils but had no detectable interactions with dendritic cells. These findings suggest that Y. pestis infection of neutrophils not only prevents their activation but may even result in their return to circulation and migration to distal sites.

Modulation of human Th17 cell responses through complement receptor 3 (CD11 b/CD18) ligation on monocyte-derived dendritic cells.

PubMed

Nowatzky, Johannes; Manches, Olivier; Khan, Shaukat Ali; Godefroy, Emmanuelle; Bhardwaj, Nina

2018-06-13

Apoptotic cell receptors contribute to the induction of tolerance by modulating dendritic cell function following the uptake of apoptotic cells or microparticles. Dendritic cells that have bound or ingested apoptotic cells produce only low amounts of pro-inflammatory cytokines and fail to prime effector T cell responses. Specifically, ligation of the apoptotic cell receptor CR3 (CD11 b/CD18) on human monocyte-derived dendritic cells (moDC) down-modates proinflammatory cytokine secretion, but the consequences for human Th17 cell homeostasis and effector responses remain unknown. Here, we aimed to establish whether CD11b-ligated moDC modulate Th17 cell effector reponses to assess their potential for future use in moDC-based suppressive immunotherapy. We generated a bead-based surrogate system to target CD11b on monocyte-derived human dendritic cells and examined the effects of CD11b ligation on Th17-skewing cytokine secretion, priming, expansion and functional plasticity in DC/T cell co-culture systems at the poly- and monoclonal level. We show that Th17 cell expansion within the human memory CD4 + T cell compartment was efficiently constricted by targeting the CD11b receptor on moDC. This tolerogenic capacity was primarily dependent on cytokine skewing. Furthermore, ligation of CD11b on healthy homozygous carriers of the rs11143679 (ITGAM) variant - a strong genetic susceptibility marker for human systemic lupus erythematosus - also down-modulated the secretion of Th17-skewing cytokines. Overall, our findings underline the potential of targeted CD11b ligation on human dendritic cells for the engineering of suppressive immunotherapy for Th17-related autoimmune disorders. Copyright © 2018 Elsevier Ltd. All rights reserved.

IMMUNOHISTOCHEMICAL ANALYSIS FOR CD21, CD35, CALDESMON AND S100 PROTEIN ON DENDRITIC CELLS TYPES IN ORAL LYMPHOMAS

PubMed Central

Mesquita, Ricardo Alves; de Araújo, Vera Cavalcanti; Paes, Roberto Antônio Pinto; Nunes, Fábio Daumas; de Sousa, Suzana Cantanhede Orsini Machado

2009-01-01

Objective: Follicular dendritic cells (FDCs) and interdigitating dendritic cells (IDCs) are dendritic cells found in lymphoid follicles, reactive follicles and in lymphomas. The goal of this study was to evaluate the presence and distribution of FDCs and IDCs in oral lymphomas. Material and Methods: Immunohistochemistry reactions were applied to 50 oral lymphomas using the antibodies anti-CD21, anti-CD35 and anti-caldesmon to FDCs, and anti-S100 protein to IDCs. Caldesmon+/FDCs and S100+/IDCs were quantified in Imagelab® software. Results: FDCs revealed by CD21 and CD35 were positively stained in two cases of diffuse large B-cell lymphoma, one MALT lymphoma, and in one case of mantle cell lymphoma. FDCs were immunopositive to caldesmon in all cases, as well as IDCs to S100 protein. Burkitt lymphoma presented a lower amount of caldesmon+/FDCs and S100+/IDCs than diffuse large B-cell lymphoma and plasmablastic lymphoma of the oral mucosa type. Conclusions: The microenvironment determined by neoplastic lymphoid cells in oral lymphomas is responsible by the development and expression of dendritic cells types. PMID:19466261

Heterogeneous integration of adult-generated granule cells into the epileptic brain

PubMed Central

Murphy, Brian L.; Pun, Raymund Y.K.; Yin, Hulian; Faulkner, Christian R.; Loepke, Andreas W.; Danzer, Steve C.

2011-01-01

The functional impact of adult-generated granule cells in the epileptic brain is unclear, with data supporting both protective and maladaptive roles. These conflicting findings could be explained if new granule cells integrate heterogeneously, with some cells taking neutral or adaptive roles, while others contribute to recurrent circuitry supporting seizures. Here, we tested this hypothesis by completing detailed morphological characterizations of age- and experience-defined cohorts of adult-generated granule cells from transgenic mice. The majority of newborn cells exposed to an epileptogenic insult exhibited reductions in dendritic spine number, suggesting reduced excitatory input to these cells. A significant subset, however, exhibited higher spine numbers. These latter cells tended to have enlarged cell bodies, long basal dendrites or both. Moreover, cells with basal dendrites received significantly more recurrent mossy fiber input through their apical dendrites, indicating that these cells are robustly integrated into the pathological circuitry of the epileptic brain. These data imply that newborn cells play complex – and potentially conflicting – roles in epilepsy. PMID:21209195

Interleukin-1 and Interferon-γ Orchestrate β-Glucan-Activated Human Dendritic Cell Programming via IκB-ζ Modulation

PubMed Central

Cardone, Marco; Dzutsev, Amiran K.; Li, Hongchuan; Riteau, Nicolas; Gerosa, Franca; Shenderov, Kevin; Winkler-Pickett, Robin; Provezza, Lisa; Riboldi, Elena; Leighty, Robert M.; Orr, Selinda J.; Steinhagen, Folkert; Wewers, Mark D.; Sher, Alan; Anderson, Stephen K.; Goldszmid, Romina; McVicar, Daniel W.

2014-01-01

Recognition of microbial components via innate receptors including the C-type lectin receptor Dectin-1, together with the inflammatory environment, programs dendritic cells (DCs) to orchestrate the magnitude and type of adaptive immune responses. The exposure to β-glucan, a known Dectin-1 agonist and component of fungi, yeasts, and certain immune support supplements, activates DCs to induce T helper (Th)17 cells that are essential against fungal pathogens and extracellular bacteria but may trigger inflammatory pathology or autoimmune diseases. However, the exact mechanisms of DC programming by β-glucan have not yet been fully elucidated. Using a gene expression/perturbation approach, we demonstrate that in human DCs β-glucan transcriptionally activates via an interleukin (IL)-1- and inflammasome-mediated positive feedback late-induced genes that bridge innate and adaptive immunity. We report that in addition to its known ability to directly prime T cells toward the Th17 lineage, IL-1 by promoting the transcriptional cofactor inhibitor of κB-ζ (IκB-ζ) also programs β-glucan-exposed DCs to express cell adhesion and migration mediators, antimicrobial molecules, and Th17-polarizing factors. Interferon (IFN)-γ interferes with the IL-1/IκB-ζ axis in β-glucan-activated DCs and promotes T cell-mediated immune responses with increased release of IFN-γ and IL-22, and diminished production of IL-17. Thus, our results identify IL-1 and IFN-γ as regulators of DC programming by β-glucan. These molecular networks provide new insights into the regulation of the Th17 response as well as new targets for the modulation of immune responses to β-glucan-containing microorganisms. PMID:25474109

Metaherpetic corneal disease in a dog associated with partial limbal stem cell deficiency and neurotrophic keratitis.

PubMed

Ledbetter, Eric C; Marfurt, Carl F; Dubielzig, Richard R

2013-07-01

To describe clinical, in vivo confocal microscopic, histopathologic, and immunohistochemical features of a dog with metaherpetic corneal disease that developed subsequent to a protracted episode of canine herpesvirus-1 (CHV-1) dendritic ulcerative keratitis. A 7-year-old, spayed-female, Miniature Schnauzer was treated for bilateral CHV-1 dendritic ulcerative keratitis. Following resolution of ulcerative keratitis, sectoral peripheral superficial corneal gray opacification, vascularization, and pigmentation slowly migrated centripetally to the axial cornea of both eyes. Corneal sensitivity measured with a Cochet-Bonnet esthesiometer was dramatically and persistently reduced. In vivo corneal confocal microscopic examination revealed regions of epithelium with a conjunctival phenotype. In these areas, the surface epithelium was thin, disorganized, and composed of hyper-reflective epithelial cells. Goblet cells and Langerhans cells were frequent, and the subbasal nerve plexus was completely absent or markedly diminished. Histopathologic abnormalities in the globes were restricted to the superficial cornea and included sectoral corneal conjunctivalization, increased anterior stromal spindle cells, and vascularization. Immunohistochemical evaluation of the corneas with anti-neurotublin antibody demonstrated attenuation of the epithelial and subbasal nerve plexuses with marked stromal hyperinnervation and increased numbers of morphologically abnormal neurites. Similar to herpes simplex virus keratitis in humans, CHV-1 ulcerative keratitis may be associated with the development of chronic degenerative corneal disease in dogs. In the described dog, this chronic corneal disease included progressive corneal opacification because of partial limbal stem cell deficiency and neurotrophic keratitis. Long-term monitoring of dogs following resolution of active CHV-1 keratitis may be indicated, particularly when ulcerations persist for an extended period. © 2012 American College of Veterinary Ophthalmologists.

The development of a 3D immunocompetent model of human skin.

PubMed

Chau, David Y S; Johnson, Claire; MacNeil, Sheila; Haycock, John W; Ghaemmaghami, Amir M

2013-09-01

As the first line of defence, skin is regularly exposed to a variety of biological, physical and chemical insults. Therefore, determining the skin sensitization potential of new chemicals is of paramount importance from the safety assessment and regulatory point of view. Given the questionable biological relevance of animal models to human as well as ethical and regulatory pressure to limit or stop the use of animal models for safety testing, there is a need for developing simple yet physiologically relevant models of human skin. Herein, we describe the construction of a novel immunocompetent 3D human skin model comprising of dendritic cells co-cultured with keratinocytes and fibroblasts. This model culture system is simple to assemble with readily-available components and importantly, can be separated into its constitutive individual layers to allow further insight into cell-cell interactions and detailed studies of the mechanisms of skin sensitization. In this study, using non-degradable microfibre scaffolds and a cell-laden gel, we have engineered a multilayer 3D immunocompetent model comprised of keratinocytes and fibroblasts that are interspersed with dendritic cells. We have characterized this model using a combination of confocal microscopy, immuno-histochemistry and scanning electron microscopy and have shown differentiation of the epidermal layer and formation of an epidermal barrier. Crucially the immune cells in the model are able to migrate and remain responsive to stimulation with skin sensitizers even at low concentrations. We therefore suggest this new biologically relevant skin model will prove valuable in investigating the mechanisms of allergic contact dermatitis and other skin pathologies in human. Once fully optimized, this model can also be used as a platform for testing the allergenic potential of new chemicals and drug leads.

Serotonin homeostasis and serotonin receptors as actors of cortical construction: special attention to the 5-HT3A and 5-HT6 receptor subtypes

PubMed Central

Vitalis, Tania; Ansorge, Mark S.; Dayer, Alexandre G.

2013-01-01

Cortical circuits control higher-order cognitive processes and their function is highly dependent on their structure that emerges during development. The construction of cortical circuits involves the coordinated interplay between different types of cellular processes such as proliferation, migration, and differentiation of neural and glial cell subtypes. Among the multiple factors that regulate the assembly of cortical circuits, 5-HT is an important developmental signal that impacts on a broad diversity of cellular processes. 5-HT is detected at the onset of embryonic telencephalic formation and a variety of serotonergic receptors are dynamically expressed in the embryonic developing cortex in a region and cell-type specific manner. Among these receptors, the ionotropic 5-HT3A receptor and the metabotropic 5-HT6 receptor have recently been identified as novel serotonergic targets regulating different aspects of cortical construction including neuronal migration and dendritic differentiation. In this review, we focus on the developmental impact of serotonergic systems on the construction of cortical circuits and discuss their potential role in programming risk for human psychiatric disorders. PMID:23801939

Pyramidal neurons in the septal and temporal CA1 field of the human and hedgehog tenrec hippocampus.

PubMed

Liagkouras, Ioannis; Michaloudi, Helen; Batzios, Christos; Psaroulis, Dimitrios; Georgiadis, Marios; Künzle, Heinz; Papadopoulos, Georgios C

2008-07-07

The present study examines comparatively the cellular density of disector-counted/Nissl-stained CA1 pyramidal neurons and the morphometric characteristics (dendritic number/length, spine number/density and Sholl-counted dendritic branch points/20 microm) of the basal and apical dendritic systems of Golgi-impregnated CA1 neurons, in the septal and temporal hippocampus of the human and hedgehog tenrec brain. The obtained results indicate that in both hippocampal parts the cellular density of the CA1 pyramidal neurons is lower in human than in tenrec. However, while the human pyramidal cell density is higher in the septal hippocampal part than in the temporal one, in the tenrec the density of these cells is higher in the temporal part. The dendritic tree of the CA1 pyramidal cells, more developed in the septal than in temporal hippocampus in both species studied, is in general more complex in the human hippocampus. The basal and the apical dendritic systems exhibit species related morphometric differences, while dendrites of different orders exhibit differences in their number and length, and in their spine density. Finally, in both species, as well as hippocampal parts and dendritic systems, changes of dendritic morphometric features along ascending dendritic orders fluctuate in a similar way, as do the number of dendritic branch points in relation to the distance from the neuron soma.

Dendritic cell and histiocytic neoplasms: biology, diagnosis, and treatment.

PubMed

Dalia, Samir; Shao, Haipeng; Sagatys, Elizabeth; Cualing, Hernani; Sokol, Lubomir

2014-10-01

Dendritic and histiocytic cell neoplasms are rare malignancies that make up less than 1% of all neoplasms arising in lymph nodes or soft tissues. These disorders have distinctive disease biology, clinical presentations, pathology, and unique treatment options. Morphology and immunohistochemistry evaluation by a hematopathologist remains key for differentiating between these neoplasms. In this review, we describe tumor biology, clinical features, pathology, and treatment of follicular dendritic cell sarcoma, interdigitating dendritic cell sarcoma, indeterminate dendritic cell sarcoma, histiocytic sarcoma, fibroblastic reticular cell tumors, and disseminated juvenile xanthogranuloma. A literature search for articles published between 1990 and 2013 was undertaken. Articles are reviewed and salient findings are systematically described. Patients with dendritic cell and histiocytic neoplasms have distinct but variable clinical presentations; however, because many tumors have recently been recognized, their true incidence is uncertain. Although the clinical features can present in many organs, most occur in the lymph nodes or skin. Most cases are unifocal and solitary presentations have good prognoses with surgical resection. The role of adjuvant therapy in these disorders remains unclear. In cases with disseminated disease, prognosis is poor and data on treatment options are limited, although chemotherapy and referral to a tertiary care center should be considered. Excisional biopsy is the preferred method of specimen collection for tissue diagnosis, and immunohistochemistry is the most important diagnostic method for differentiating these disorders from other entities. Dendritic cell and histiocytic cell neoplasms are rare hematological disorders with variable clinical presentations and prognoses. Immunohistochemistry remains important for diagnosis. Larger pooled analyses or clinical trials are needed to better understand optimal treatment options in these rare disorders. Whenever possible, patients should be referred to a tertiary care center for disease management.

The Global Spike: Conserved Dendritic Properties Enable Unique Ca2+ Spike Generation in Low-Threshold Spiking Neurons.

PubMed

Connelly, William M; Crunelli, Vincenzo; Errington, Adam C

2015-11-25

Low-threshold Ca(2+) spikes (LTS) are an indispensible signaling mechanism for neurons in areas including the cortex, cerebellum, basal ganglia, and thalamus. They have critical physiological roles and have been strongly associated with disorders including epilepsy, Parkinson's disease, and schizophrenia. However, although dendritic T-type Ca(2+) channels have been implicated in LTS generation, because the properties of low-threshold spiking neuron dendrites are unknown, the precise mechanism has remained elusive. Here, combining data from fluorescence-targeted dendritic recordings and Ca(2+) imaging from low-threshold spiking cells in rat brain slices with computational modeling, the cellular mechanism responsible for LTS generation is established. Our data demonstrate that key somatodendritic electrical conduction properties are highly conserved between glutamatergic thalamocortical neurons and GABAergic thalamic reticular nucleus neurons and that these properties are critical for LTS generation. In particular, the efficiency of soma to dendrite voltage transfer is highly asymmetric in low-threshold spiking cells, and in the somatofugal direction, these neurons are particularly electrotonically compact. Our data demonstrate that LTS have remarkably similar amplitudes and occur synchronously throughout the dendritic tree. In fact, these Ca(2+) spikes cannot occur locally in any part of the cell, and hence we reveal that LTS are generated by a unique whole-cell mechanism that means they always occur as spatially global spikes. This all-or-none, global electrical and biochemical signaling mechanism clearly distinguishes LTS from other signals, including backpropagating action potentials and dendritic Ca(2+)/NMDA spikes, and has important consequences for dendritic function in low-threshold spiking neurons. Low-threshold Ca(2+) spikes (LTS) are critical for important physiological processes, including generation of sleep-related oscillations, and are implicated in disorders including epilepsy, Parkinson's disease, and schizophrenia. However, the mechanism underlying LTS generation in neurons, which is thought to involve dendritic T-type Ca(2+) channels, has remained elusive due to a lack of knowledge of the dendritic properties of low-threshold spiking cells. Combining dendritic recordings, two-photon Ca(2+) imaging, and computational modeling, this study reveals that dendritic properties are highly conserved between two prominent low-threshold spiking neurons and that these properties underpin a whole-cell somatodendritic spike generation mechanism that makes the LTS a unique global electrical and biochemical signal in neurons. Copyright © 2015 Connelly et al.

FURTHER STUDY OF SOMA, DENDRITE, AND AXON EXCITATION IN SINGLE NEURONS

PubMed Central

Eyzaguirre, Carlos; Kuffler, Stephen W.

1955-01-01

The present investigation continues a previous study in which the soma-dendrite system of sensory neurons was excited by stretch deformation of the peripheral dendrite portions. Recording was done with intracellular leads which were inserted into the cell soma while the neuron was activated orthodromically or antidromically. The analysis was also extended to axon conduction. Crayfish, Procambarus alleni (Faxon) and Orconectes virilis (Hagen), were used. 1. The size and time course of action potentials recorded from the soma-dendrite complex vary greatly with the level of the cell's membrane potential. The latter can be changed over a wide range by stretch deformation which sets up a "generator potential" in the distal portions of the dendrites. If a cell is at its resting unstretched equilibrium potential, antidromic stimulation through the axon causes an impulse which normally overshoots the resting potential and decays into an afternegativity of 15 to 20 msec. duration. The postspike negativity is not followed by an appreciable hyperpolarization (positive) phase. If the membrane potential is reduced to a new steady level a postspike positivity appears and increases linearly over a depolarization range of 12 to 20 mv. in various cells. At those levels the firing threshold of the cell for orthodromic discharges is generally reached. 2. The safety factor for conduction between axon and cell soma is reduced under three unrelated conditions, (a) During the recovery period (2 to 3 msec.) immediately following an impulse which has conducted fully over the cell soma, a second impulse may be delayed, may invade the soma partially, or may be blocked completely. (b) If progressive depolarization is produced by stretch, it leads to a reduction of impulse height and eventually to complete block of antidromic soma invasion, resembling cathodal block, (c) In some cells, when the normal membrane potential is within several millivolts of the relaxed resting state, an antidromic impulse may be blocked and may set up within the soma a local potential only. The local potential can sum with a second one or it may sum with potential changes set up in the dendrites, leading to complete invasion of the soma. Such antidromic invasion block can always be relieved by appropriate stretch which shifts the membrane potential out of the "blocking range" nearer to the soma firing level. During the afterpositivity of an impulse in a stretched cell the membrane potential may fall below or near the blocking range. During that period another impulse may be delayed or blocked. 3. Information regarding activity and conduction in dendrites has been obtained indirectly, mainly by analyzing the generator action under various conditions of stretch. The following conclusions have been reached: The large dendrite branches have similar properties to the cell body from which they arise and carry the same kind of impulses. In the finer distal filaments of even lightly depolarized dendrites, however, no axon type all-or-none conduction occurs since the generator potential persists to a varying degree during antidromic invasion of the cell. With the membrane potential at its resting level the dendrite terminals contribute to the prolonged impulse afternegativity of the soma. 4. Action potentials in impaled axons and in cell bodies have been compared. It is thought that normally the over-all duration of axon impulses is shorter. Local activity during reduction of the safety margin for conduction was studied. 5. An analysis was made of high frequency grouped discharges which occasionally arise in cells. They differ in many essential aspects from the regular discharges set up by the generator action. It is proposed that grouped discharges occur only when invasion of dendrites is not synchronous, due to a delay in excitation spread between soma and dendrites. Each impulse in a group is assumed to be caused by an impulse in at least one of the large dendrite branches. Depolarization of dendrites abolishes the grouped activity by facilitating invasion of the large dendrite branches. PMID:13252238

The DC-SIGN-CD56 interaction inhibits the anti-dendritic cell cytotoxicity of CD56 expressing cells.

PubMed

Nabatov, Alexey A; Raginov, Ivan S

2015-01-01

This study aimed to clarify interactions of the pattern-recognition receptor DC-SIGN with cells from the HIV-infected peripheral blood lymphocyte cultures. Cells from control and HIV-infected peripheral blood lymphocyte cultures were tested for the surface expression of DC-SIGN ligands. The DC-SIGN ligand expressing cells were analyzed for the role of DC-SIGN-ligand interaction in their functionality. In the vast majority of experiments HIV-infected lymphocytes did not express detectable DC-SIGN ligands on their cell surfaces. In contrast, non-infected cells, carrying NK-specific marker CD56, expressed cell surface DC-SIGN ligands. The weakly polysialylated CD56 was identified as a novel DC-SIGN ligand. The treatment of DC-SIGN expressing dendritic cells with anti-DC-SIGN antibodies increased the anti-dendritic cell cytotoxicity of CD56(pos) cells. The treatment of CD56(pos) cells with a peptide, blocking the weakly polysialylated CD56-specifc trans-homophilic interactions, inhibited their anti-dendritic cells cytotoxicity. The interaction between DC-SIGN and CD56 inhibits homotypic intercellular interactions of CD56(pos) cells and protects DC-SIGN expressing dendritic cells against CD56(pos) cell-mediated cytotoxicity. This finding can have an impact on the development of approaches to HIV infection and cancer therapy as well as in transplantation medicine.

Interfering of the Reelin/ApoER2/PSD95 Signaling Axis Reactivates Dendritogenesis of Mature Hippocampal Neurons.

PubMed

Ampuero, Estibaliz; Jury, Nur; Härtel, Steffen; Marzolo, María-Paz; van Zundert, Brigitte

2017-05-01

Reelin, an extracellular glycoprotein secreted in embryonic and adult brain, participates in neuronal migration and neuronal plasticity. Extensive evidence shows that reelin via activation of the ApoER2 and VLDLR receptors promotes dendrite and spine formation during early development. Further evidence suggests that reelin signaling is needed to maintain a stable architecture in mature neurons, but, direct evidence is lacking. During activity-dependent maturation of the neuronal circuitry, the synaptic protein PSD95 is inserted into the postsynaptic membrane to induce structural refinement and stability of spines and dendrites. Given that ApoER2 interacts with PSD95, we tested if reelin signaling interference in adult neurons reactivates the dendritic architecture. Unlike findings in developing cultures, the presently obtained in vitro and in vivo data show, for the first time, that reelin signaling interference robustly increase dendritogenesis and reduce spine density in mature hippocampal neurons. In particular, the expression of a mutant ApoER2 form (ApoER2-tailless), which is unable to interact with PSD95 and hence cannot transduce reelin signaling, resulted in robust dendritogenesis in mature hippocampal neurons in vitro. These results indicate that reelin/ApoER2/PSD95 signaling is important for neuronal structure maintenance in mature neurons. Mechanistically, obtained immunofluorescent data indicate that reelin signaling impairment reduced synaptic PSD95 levels, consequently leading to synaptic re-insertion of NR2B-NMDARs. Our findings underscore the importance of reelin in maintaining adult network stability and reveal a new mode for reactivating dendritogenesis in neurological disorders where dendritic arbor complexity is limited, such as in depression, Alzheimer's disease, and stroke. J. Cell. Physiol. 232: 1187-1199, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Interaction of an opportunistic fungus Purpureocillium lilacinum with human macrophages and dendritic cells.

PubMed

Peixoto, Mariana Lima Perazzini; Santos, Dilvani Oliveira; Souza, Ivy de Castro Campos de; Neri, Eloah Christina Lyrio; Sequeira, Danielly Correa Moreira de; De Luca, Paula Mello; Borba, Cíntia de Moraes

2014-01-01

Purpureocillium lilacinum is emerging as a causal agent of hyalohyphomycosis that is refractory to antifungal drugs; however, the pathogenic mechanisms underlying P. lilacinum infection are not understood. In this study, we investigated the interaction of P. lilacinum conidia with human macrophages and dendritic cells in vitro. Spores of a P. lilacinum clinical isolate were obtained by chill-heat shock. Mononuclear cells were isolated from eight healthy individuals. Monocytes were separated by cold aggregation and differentiated into macrophages by incubation for 7 to 10 days at 37°C or into dendritic cells by the addition of the cytokines human granulocyte-macrophage colony stimulating factor and interleukin-4. Conidial suspension was added to the human cells at 1:1, 2:1, and 5:1 (conidia:cells) ratios for 1h, 6h, and 24h, and the infection was evaluated by Giemsa staining and light microscopy. After 1h interaction, P. lilacinum conidia were internalized by human cells and after 6h contact, some conidia became inflated. After 24h interaction, the conidia produced germ tubes and hyphae, leading to the disruption of macrophage and dendritic cell membranes. The infection rate analyzed after 6h incubation of P. lilacinum conidia with cells at 2:1 and 1:1 ratios was 76.5% and 25.5%, respectively, for macrophages and 54.3% and 19.5%, respectively, for cultured dendritic cells. P. lilacinum conidia are capable of infecting and destroying both macrophages and dendritic cells, clearly demonstrating the ability of this pathogenic fungus to invade human phagocytic cells.

Three-dimensional spatial modeling of spines along dendritic networks in human cortical pyramidal neurons

PubMed Central

Larrañaga, Pedro; Benavides-Piccione, Ruth; Fernaud-Espinosa, Isabel; DeFelipe, Javier; Bielza, Concha

2017-01-01

We modeled spine distribution along the dendritic networks of pyramidal neurons in both basal and apical dendrites. To do this, we applied network spatial analysis because spines can only lie on the dendritic shaft. We expanded the existing 2D computational techniques for spatial analysis along networks to perform a 3D network spatial analysis. We analyzed five detailed reconstructions of adult human pyramidal neurons of the temporal cortex with a total of more than 32,000 spines. We confirmed that there is a spatial variation in spine density that is dependent on the distance to the cell body in all dendrites. Considering the dendritic arborizations of each pyramidal cell as a group of instances of the same observation (the neuron), we used replicated point patterns together with network spatial analysis for the first time to search for significant differences in the spine distribution of basal dendrites between different cells and between all the basal and apical dendrites. To do this, we used a recent variant of Ripley’s K function defined to work along networks. The results showed that there were no significant differences in spine distribution along basal arbors of the same neuron and along basal arbors of different pyramidal neurons. This suggests that dendritic spine distribution in basal dendritic arbors adheres to common rules. However, we did find significant differences in spine distribution along basal versus apical networks. Therefore, not only do apical and basal dendritic arborizations have distinct morphologies but they also obey different rules of spine distribution. Specifically, the results suggested that spines are more clustered along apical than in basal dendrites. Collectively, the results further highlighted that synaptic input information processing is different between these two dendritic domains. PMID:28662210

Three-dimensional spatial modeling of spines along dendritic networks in human cortical pyramidal neurons.

PubMed

Anton-Sanchez, Laura; Larrañaga, Pedro; Benavides-Piccione, Ruth; Fernaud-Espinosa, Isabel; DeFelipe, Javier; Bielza, Concha

2017-01-01

We modeled spine distribution along the dendritic networks of pyramidal neurons in both basal and apical dendrites. To do this, we applied network spatial analysis because spines can only lie on the dendritic shaft. We expanded the existing 2D computational techniques for spatial analysis along networks to perform a 3D network spatial analysis. We analyzed five detailed reconstructions of adult human pyramidal neurons of the temporal cortex with a total of more than 32,000 spines. We confirmed that there is a spatial variation in spine density that is dependent on the distance to the cell body in all dendrites. Considering the dendritic arborizations of each pyramidal cell as a group of instances of the same observation (the neuron), we used replicated point patterns together with network spatial analysis for the first time to search for significant differences in the spine distribution of basal dendrites between different cells and between all the basal and apical dendrites. To do this, we used a recent variant of Ripley's K function defined to work along networks. The results showed that there were no significant differences in spine distribution along basal arbors of the same neuron and along basal arbors of different pyramidal neurons. This suggests that dendritic spine distribution in basal dendritic arbors adheres to common rules. However, we did find significant differences in spine distribution along basal versus apical networks. Therefore, not only do apical and basal dendritic arborizations have distinct morphologies but they also obey different rules of spine distribution. Specifically, the results suggested that spines are more clustered along apical than in basal dendrites. Collectively, the results further highlighted that synaptic input information processing is different between these two dendritic domains.

Input Source and Strength Influences Overall Firing Phase of Model Hippocampal CA1 Pyramidal Cells During Theta: Relevance to REM Sleep Reactivation and Memory Consolidation

PubMed Central

Booth, Victoria; Poe, Gina R.

2005-01-01

In simulation studies using a realistic model CA1 pyramidal cell, we accounted for the shift in mean firing phase from theta cycle peaks to theta cycle troughs during REM sleep reactivation of hippocampal CA1 place cells over several days of growing familiarization with an environment (Poe et al., 2000). Changes in the theta drive between proximal and distal dendritic regions of the cell modulated the theta phase of firing when stimuli were presented at proximal and distal dendritic locations. Stimuli at proximal dendritic sites (proximal to 100 μm from the soma) invoked firing with a significant phase preference at the depolarizing theta peaks, while distal stimuli (> 290 μm from the soma) invoked firing at hyperpolarizing theta troughs. The location-related phase preference depended on active dendritic conductances, a sufficient electrotonic separation between input sites and theta-induced subthreshold membrane potential oscillations in the cell. The simulation results predict that the shift in mean theta phase during REM sleep cellular reactivation could occur through potentiation of distal dendritic (temporo-ammonic) synapses and depotentiation of proximal dendritic (Schaffer collateral) synapses over the course of familiarization. PMID:16411243

Galectin-9 binds to O-glycans on protein disulfide isomerase.

PubMed

Schaefer, Katrin; Webb, Nicholas E; Pang, Mabel; Hernandez-Davies, Jenny E; Lee, Katharine P; Gonzalez, Pascual; Douglass, Martin V; Lee, Benhur; Baum, Linda G

2017-09-01

Changes in the T cell surface redox environment regulate critical cell functions, such as cell migration, viral entry and cytokine production. Cell surface protein disulfide isomerase (PDI) contributes to the regulation of T cell surface redox status. Cell surface PDI can be released into the extracellular milieu or can be internalized by T cells. We have found that galectin-9, a soluble lectin expressed by T cells, endothelial cells and dendritic cells, binds to and retains PDI on the cell surface. While endogenous galectin-9 is not required for basal cell surface PDI expression, exogenous galectin-9 mediated retention of cell surface PDI shifted the disulfide/thiol equilibrium on the T cell surface. O-glycans on PDI are required for galectin-9 binding, and PDI recognition appears to be specific for galectin-9, as galectin-1 and galectin-3 do not bind PDI. Galectin-9 is widely expressed by immune and endothelial cells in inflamed tissues, suggesting that T cells would be exposed to abundant galectin-9, in cis and in trans, in infectious or autoimmune conditions. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Mesenchymal Stromal Cells Prevent Allostimulation In Vivo and Control Checkpoints of Th1 Priming: Migration of Human DC to Lymph Nodes and NK Cell Activation.

PubMed

Consentius, C; Akyüz, L; Schmidt-Lucke, J A; Tschöpe, C; Pinzur, L; Ofir, R; Reinke, P; Volk, H-D; Juelke, K

2015-10-01

Although the immunomodulatory potency of mesenchymal stromal cells (MSC) is well established, the mechanisms behind are still not clear. The crosstalk between myeloid dendritic cells (mDC) and natural killer (NK) cells and especially NK cell-derived interferon-gamma (IFN-γ) play a pivotal role in the development of type 1 helper (Th1) cell immune responses. While many studies explored the isolated impact of MSC on either in vitro generated DC, NK, or T cells, there are only few data available on the complex interplay between these cells. Here, we investigated the impact of MSC on the functionality of human mDC and the consequences for NK cell and Th1 priming in vitro and in vivo. In critical limb ischemia patients, who have been treated with allogeneic placenta-derived mesenchymal-like stromal cells (PLX-PAD), no in vivo priming of Th1 responses toward the major histocompatibility complex (MHC) mismatches could be detected. Further in vitro studies revealed that mDC reprogramming could play a central role for these effects. Following crosstalk with MSC, activated mDC acquired a tolerogenic phenotype characterized by reduced migration toward CCR7 ligand and impaired ability to stimulate NK cell-derived IFN-γ production. These effects, which were strongly related to an altered interleukin (IL)-12/IL-10 production by mDC, were accompanied by an effective prevention of Th1 priming in vivo. Our findings provide novel evidence for the regulation of Th1 priming by MSC via modulation of mDC and NK cell crosstalk and show that off-the-shelf produced MHC-mismatched PLX-PAD can be used in patients without any sign of immunogenicity. © 2015 AlphaMed Press.

The neuronal structure of paramamillary nuclei in Bison bonasus: Nissl and Golgi pictures.

PubMed

Robak, A; Szteyn, S; Równiak, M

1998-01-01

The studies were carried out on the hypothalamus of bison bonasus aged 2 and 3 months. Sections were made by means of Bagiński's technique and Nissl and Klüver-Barrera methods. Four types of neurons were distinguished in the paramamillary nuclei: nucleus supramamillaris (Sm) and nucleus tuberomammillaris pars posterior (Tmp). Type I, small and medium-size, triangular or fusiform cells, which have 2-3 slender, poorly ramified dendrites; typical leptodendritic neurons. Type II, medium size neurons with quadrangular or spindle-shaped perikaryons. Most of them have 3-4 thick dendritic trunks with ramifying relatively long dendrites. These cells show stalked-appearance and possess different appendages sparsely distributed. Type III is similar to type II, but is made of medium-size to large multipolar cells having quadrangular, triangular or fusiform perikaryons and relatively short dendrites. Type IV, small and medium-size, globular cells with 2 or 3 dendritic trunks, which dichotomously subdivide into quaternary dendrites. In all types of neurons, axons emerge from the perikaryon or initial portion of a dendritic trunk. Type I was found in both studied nuclei. Types II and III constitute mainly the nucleus tuberomamillaris pars posterior. Type IV preponderate in the nucleus supramamillaris. The characteristic feature of Tmp cells, in Nissl picture was irregular contour of their somas and clumps of rough Nisls granules, which appear to lie outside the perikaryons. In Sm there were also lightly stained small rounded cells having both small amount of the cytoplasm and tigroid matter.

Evaluation of Immune Responses Mediated by Listeria-Stimulated Human Dendritic Cells: Implications for Cancer Vaccine Therapy

DTIC Science & Technology

2012-07-01

Mediated by Listeria -Stimulated Human Dendritic Cells: Implications for Cancer Vaccine Therapy PRINCIPAL INVESTIGATOR: David J. Chung, M D , Ph D...CONTRACT NUMBER Evaluation of Immune Responses Mediated by Listeria -Stimulated Human Dendritic Cells: Implications for Cancer Vaccine Therapy 5b...Distribution Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT The purpose of this project is to study the immunomodulatory effect of Listeria on

Dendritic cell immunization route determines CD8+ T cell trafficking to inflamed skin: role for tissue microenvironment and dendritic cells in establishment of T cell-homing subsets.

PubMed

Dudda, Jan C; Simon, Jan C; Martin, Stefan

2004-01-15

The effector/memory T cell pool branches in homing subsets selectively trafficking to organs such as gut or skin. Little is known about the critical factors in the generation of skin-homing CD8+ T cells, although they are crucial effectors in skin-restricted immune responses such as contact hypersensitivity and melanoma defense. In this study, we show that intracutaneous, but not i.v. injection of bone marrow-derived dendritic cells induced skin-homing CD8+ T cells with up-regulated E-selectin ligand expression and effector function in contact hypersensitivity. The skin-homing potential and E-selectin ligand expression remained stable in memory phase without further Ag contact. In contrast, i.p. injection induced T cells expressing the gut-homing integrin alpha(4)beta(7). Although differential expression of these adhesion molecules was strictly associated with the immunization route, the postulated skin-homing marker CCR4 was transiently up-regulated in all conditions. Interestingly, dendritic cells from different tissues effectively induced the corresponding homing markers on T cells in vitro. Our results suggest a crucial role for the tissue microenvironment and dendritic cells in the instruction of T cells for tissue-selective homing and demonstrate that Langerhans cells are specialized to target T cells to inflamed skin.

The local lymph node assay being too sensitive?

PubMed

Hans-Werner, Vohr; Jürgen, Ahr Hans

2005-12-01

The local lymph node assay (LLNA) and modifications thereof were recently recognized by the OECD as stand-alone methods for the detection of skin-sensitizing potential. However, although the validity of the LLNA was acknowledged by the ICCVAM, attention was drawn to one major problem, i.e., the possibility of false positive results caused by non-specific cell activation as a result of inflammatory processes in the skin (irritation). This is based on the fact that inflammatory processes in the skin may lead to non-specific activation of dendritic cells, cell migration and non-specific proliferation of lymph node cells. Measuring cell proliferation by radioactive or non-radioactive methods, without taking the irritating properties of test items into account, leads thus to false positive reactions. In this paper, we have compared both endpoints: (1) cell proliferation alone and (2) cell proliferation in combination with inflammatory (irritating) processes. It turned out that a considerable number of tests were "false positive" to the definition mentioned above. By excluding such false positive results the LLNA seems not to be more sensitive than relevant guinea pig assays. These various methods and results are described here.

The expression and function of cathepsin E in dendritic cells.

PubMed

Chain, Benjamin M; Free, Paul; Medd, Patrick; Swetman, Claire; Tabor, Alethea B; Terrazzini, Nadia

2005-02-15

Cathepsin E is an aspartic proteinase that has been implicated in Ag processing within the class II MHC pathway. In this study, we document the presence of cathepsin E message and protein in human myeloid dendritic cells, the preeminent APCs of the immune system. Cathepsin E is found in a perinuclear compartment, which is likely to form part of the endoplasmic reticulum, and also a peripheral compartment just beneath the cell membrane, with a similar distribution to that of Texas Red-dextran within 2 min of endocytosis. To investigate the function of cathepsin E in processing, a new soluble targeted inhibitor was synthesized by linking the microbial aspartic proteinase inhibitor pepstatin to mannosylated BSA via a cleavable disulfide linker. This inhibitor was shown to block cathepsin D/E activity in cell-free assays and within dendritic cells. The inhibitor blocked the ability of dendritic cells from wild-type as well as cathepsin D-deficient mice to present intact OVA, but not an OVA-derived peptide, to cognate T cells. The data therefore support the hypothesis that cathepsin E has an important nonredundant role in the class II MHC Ag processing pathway within dendritic cells.

Blastic plasmacytoid dendritic cell neoplasm in an elderly woman.

PubMed

Foong, H B B; Chong, M; Taylor, E M; Carlson, J A; Petrella, T

2013-04-01

Blastic plasmacytoid dendritic cell neoplasm (a.k.a. NK cell lymphoma, CD4+CD56+ haematodermic neoplasm) is a rare aggressive tumour that arises from plasmacytoid dendritic cell precursors. We report the first case from Malaysia of a 79-year-old Chinese woman who presented with purpuric plaques and nodules produced by pleomorphic CD4+, CD56+, CD68+, CD123+ and CD303+, but CD2APmononuclear cell infiltrates. Leukemic dissemination occurred and she succumbed to disease without treatment 4 weeks after diagnosis and 9 months after onset of cutaneous disease.

A noninvasive optical approach for assessing chloride extrusion activity of the K-Cl cotransporter KCC2 in neuronal cells.

PubMed

Ludwig, Anastasia; Rivera, Claudio; Uvarov, Pavel

2017-01-31

Cation-chloride cotransporters (CCCs) are indispensable for maintaining chloride homeostasis in multiple cell types, but K-Cl cotransporter KCC2 is the only CCC member with an exclusively neuronal expression in mammals. KCC2 is critical for rendering fast hyperpolarizing responses of ionotropic γ-aminobutyric acid and glycine receptors in adult neurons, for neuronal migration in the developing central nervous system, and for the formation and maintenance of small dendritic protrusions-dendritic spines. Deficit in KCC2 expression and/or activity is associated with epilepsy and neuropathic pain, and effective strategies are required to search for novel drugs augmenting KCC2 function. We revised current methods to develop a noninvasive optical approach for assessing KCC2 transport activity using a previously characterized genetically encoded chloride sensor. Our protocol directly assesses dynamics of KCC2-mediated chloride efflux and allows measuring genuine KCC2 activity with good spatial and temporal resolution. As a proof of concept, we used this approach to compare transport activities of the two known KCC2 splice isoforms, KCC2a and KCC2b, in mouse neuronal Neuro-2a cells. Our noninvasive optical protocol proved to be efficient for assessment of furosemide-sensitive chloride fluxes. Transport activities of the N-terminal splice isoforms KCC2a and KCC2b obtained by the novel approach matched to those reported previously using standard methods for measuring chloride fluxes.

Lactobacillus delbrueckii subsp lactis CIDCA 133 modulates response of human epithelial and dendritic cells infected with Bacillus cereus.

PubMed

Rolny, I S; Tiscornia, I; Racedo, S M; Pérez, P F; Bollati-Fogolín, M

2016-11-30

It is known that probiotic microorganisms are able to modulate pathogen virulence. This ability is strain dependent and involves multiple interactions between microorganisms and relevant host's cell populations. In the present work we focus on the effect of a potentially probiotic lactobacillus strain (Lactobacillus delbrueckii subsp. lactis CIDCA 133) in an in vitro model of Bacillus cereus infection. Our results showed that infection of intestinal epithelial HT-29 cells by B. cereus induces nuclear factor kappa B (NF-κB) pathway. Noteworthy, the presence of strain L. delbrueckii subsp.lactis CIDCA 133 increases stimulation. However, B. cereus-induced interleukin (IL)-8 production by epithelial cells is partially abrogated by L. delbrueckii subsp. lactis CIDCA 133. These findings suggest that signalling pathways other than that of NF-κB are involved. In a co-culture system (HT-29 and monocyte-derived dendritic cells), B. cereus was able to translocate from the epithelial (upper) to the dendritic cell compartment (lower). This translocation was partially abrogated by the presence of lactobacilli in the upper compartment. In addition, infection of epithelial cells in the co-culture model, led to an increase in the expression of CD86 by dendritic cells. This effect could not be modified in the presence of lactobacilli. Interestingly, infection of enterocytes with B. cereus triggers production of proinflammatory cytokines by dendritic cells (IL-8, IL-6 and tumour necrosis factor alpha (TNF-α)). The production of TNF-α (a protective cytokine in B. cereus infections) by dendritic cells was increased in the presence of lactobacilli. The present work demonstrates for the first time the effect of L. delbrueckii subsp. lactis CIDCA 133, a potentially probiotic strain, in an in vitro model of B. cereus infection. The presence of the probiotic strain modulates cell response both in infected epithelial and dendritic cells thus suggesting a possible beneficial effect of selected lactobacilli strains on the course of B. cereus infection.

Intercellular Adhesion Molecule-5 Induces Dendritic Outgrowth by Homophilic Adhesion

PubMed Central

Tian, Li; Nyman, Henrietta; Kilgannon, Patrick; Yoshihara, Yoshihiro; Mori, Kensaku; Andersson, Leif C.; Kaukinen, Sami; Rauvala, Heikki; Gallatin, W. Michael; Gahmberg, Carl G.

2000-01-01

Intercellular adhesion molecule-5 (ICAM-5) is a dendritically polarized membrane glycoprotein in telencephalic neurons, which shows heterophilic binding to leukocyte β2-integrins. Here, we show that the human ICAM-5 protein interacts in a homophilic manner through the binding of the immunoglobulin domain 1 to domains 4–5. Surface coated ICAM-5-Fc promoted dendritic outgrowth and arborization of ICAM- 5–expressing hippocampal neurons. During dendritogenesis in developing rat brain, ICAM-5 was in monomer form, whereas in mature neurons it migrated as a high molecular weight complex. The findings indicate that its homophilic binding activity was regulated by nonmonomer/monomer transition. Thus, ICAM-5 displays two types of adhesion activity, homophilic binding between neurons and heterophilic binding between neurons and leukocytes. PMID:10893271

Feline atopic dermatitis. A model for Langerhans cell participation in disease pathogenesis.

PubMed

Roosje, P J; Whitaker-Menezes, D; Goldschmidt, M H; Moore, P F; Willemse, T; Murphy, G F

1997-10-01

Atopic dermatitis is a disorder characterized by cutaneous exanthemata as a consequence of exaggerated eczematous reactions to topical and systemic allergens. Langerhans cells, expressing CD1a and HLA-DR, and dermal dendritic cells, expressing HLA-DR, are known to be potent antigen-presenting cells and are thought to play an important role in the pathogenesis of atopic dermatitis. The immunophenotype of lesional skin in atopic dermatitis in humans involves increased numbers of CD1a+/MHC class II+ dendritic cells in addition to activated T cells, mast cells, and macrophages. To establish feline skin as a model for the study of human atopic dermatitis, and to elucidate the role of dendritic cells in feline atopic dermatitis, we investigated the presence of CD1a+ cells and MHC class II+ cells in the epidermis and dermis of lesional feline skin and in skin of healthy control animals. Immunohistochemistry revealed that MHC class II+ epidermal dendritic cells were CD1a+ in normal feline skin and significantly increased numbers of CD1a+ cells and MHC class II+ cells were present in the epidermis and dermis of lesional skin. These data provide the first correlative documentation of CD1a expression by feline dendritic cells containing Birbeck granules, and indicate the utility of feline skin in the study of human cutaneous atopy.

Plasmacytoid dendritic cell leukaemia/lymphoma: towards a well defined entity?

PubMed

Garnache-Ottou, Francine; Feuillard, Jean; Saas, Philippe

2007-02-01

CD4(+)/CD56(+) haematodermic neoplasm or 'early' plasmacytoid dendritic cell leukaemia/lymphoma (pDCL) was described as a disease entity in the last World Health Organisation/European Organisation for Research and Treatment of Cancer classification for cutaneous lymphomas. These leukaemia/lymphomas co-express CD4 and CD56 without any other lineage-specific markers and have been identified as arising from plasmacytoid dendritic cells. Despite a fairly homogeneous pattern of markers expressed by most pDCL, numerous distinctive features (e.g. cytological aspects and aberrant marker expression) have been reported. This may be related to the 'lineage-independent developmental' programme of dendritic cells, which may be able to develop from either immature or already committed haematopoietic progenitors. This highlights the need for specific validated markers to diagnose such aggressive leukaemia. Here, we propose--among others (e.g. T-cell leukaemia 1)--blood dendritic cell antigen-2 and high levels of CD123 expression as potential markers. In addition, we propose a multidisciplinary approach including several fields of haematology to improve pDCL diagnosis.

The types of neurons of the somatic oculomotor nucleus in the European bison. Nissl and Golgi studies.

PubMed

Szteyn, S; Robak, A; Równiak, M

1997-01-01

The neuronal structure of the somatic oculomotor nucleus (SON) was studied on the basis of Nissl and Golgi preparations, obtained from mesencephalons of 4 European bisons. We distinguished four types of neurons in the investigated nucleus: 1. The large multipolar nerve cells with 5-8 thick dendritic trunks and a thin axon which emerges directly from the soma. These are the most numerous neurons in the SON. 2. The small multipolar neurons. These cells have 4-6 thick dendritic trunks. An axon arises mostly from initial segment of one of the dendrites. This type represents about 8% neurons of SON. 3. The triangular neurons. From perikaryon 3 thick dendritic trunks emerge. A thin axon arises directly from the cell body. These cells make about 10% neurons of SON. 4. The pear-shaped cells which have 1 or 2 dendritic trunks concentrate at one pole of the neurons. In the SON there are about 2% pear-shaped cells. Their features correspond to the features attributed by many authors to the interneurons.

Interactions between airway epithelial cells and dendritic cells during viral infections using an in vitro co-culture model

EPA Science Inventory

Rationale: Historically, single cell culture models have been limited in pathological and physiological relevance. A co-culture model of dendritic cells (DCs) and differentiated human airway epithelial cells was developed to examine potential interactions between these two cell t...

Interactions of Cryptococcus with Dendritic Cells

PubMed Central

Wozniak, Karen L.

2018-01-01

The fungal pathogens Cryptococcus neoformans and Cryptococcus gattii can cause life-threatening infections in immune compromised and immune competent hosts. These pathogens enter the host via inhalation, and respiratory tract innate immune cells such as dendritic cells (DCs) are one of the first host cells they encounter. The interactions between Cryptococcus and innate immune cells play a critical role in the progression of disease in the host. This review will focus specifically on the interactions between Cryptococcus and dendritic cells (DCs), including recognition/processing by DCs, effects of immune mediators on DC recruitment and activity, and the potential for DC vaccination against cryptococcosis. PMID:29543719

Interactions of Cryptococcus with Dendritic Cells.

PubMed

Wozniak, Karen L

2018-03-15

The fungal pathogens Cryptococcus neoformans and Cryptococcus gattii can cause life-threatening infections in immune compromised and immune competent hosts. These pathogens enter the host via inhalation, and respiratory tract innate immune cells such as dendritic cells (DCs) are one of the first host cells they encounter. The interactions between Cryptococcus and innate immune cells play a critical role in the progression of disease in the host. This review will focus specifically on the interactions between Cryptococcus and dendritic cells (DCs), including recognition/processing by DCs, effects of immune mediators on DC recruitment and activity, and the potential for DC vaccination against cryptococcosis.

New Directions for Natural Killer T Cells in the Immunotherapy of Cancer

PubMed Central

Teyton, Luc

2017-01-01

Natural killer T (NKT) cells have been placed at the interface between innate and adaptive immunity by a long series of experiments that convincingly showed that beyond cytokine secretion and NK cell recruitment, NKT cells were coordinating dendritic cell and B cell maturation through direct membrane contacts and initiate productive responses. As such, NKT cells are the cellular adjuvant of many immune reactions and have functions that go much beyond what their name encapsulates. In addition, the initial discovery of the ligands of NKT cells is deeply linked to cancer biology and therapy. However, for a host of reasons, animal models in which agonists of NKT cells were used did not translate well to human cancers. A systematic reassessment of NKT cells role in tumorigenesis, especially spontaneous one, is now accessible using single cell analysis technologies both in mouse and man, and should be taken advantage of. Similarly, the migration, localization, phenotype of NKT cells following induced expansion after injection of an agonist can be examined at the single cell level. This technological revolution will help evaluate where and how NKT cells can be used in cancer. PMID:29209309

The distribution of excitatory amino acid receptors on acutely dissociated dorsal horn neurons from postnatal rats.

PubMed

Arancio, O; Yoshimura, M; Murase, K; MacDermott, A B

1993-01-01

Excitatory amino acid receptor distribution was mapped on acutely dissociated neurons from postnatal rat spinal cord dorsal horn. N-methyl D-aspartate, quisqualate and kainate were applied to multiple locations along the somal and dendritic surfaces of voltage-clamped neurons by means of a pressure application system. To partially compensate for the decrement of response amplitude due to current loss between the site of activation on the dendrite and the recording electrode at the soma, a solution containing 0.15 M KCl was applied on the cell bodies and dendrites of some cells to estimate an empirical length constant. In the majority of the cells tested, the dendritic membrane had regions of higher sensitivity to excitatory amino acid agonists than the somatic membrane, with dendritic response amplitudes reaching more than seven times those at the cell body. A comparison of the relative changes in sensitivity between each combination of two of the three excitatory amino acid agonists along the same dendrite showed different patterns of agonist sensitivity along the dendrite in the majority of the cells. These data were obtained from dorsal horn neurons that had developed and formed synaptic connections in vivo. They demonstrate that in contrast to observations made on ventral horn neurons, receptor density for all the excitatory amino acid receptors on dorsal horn neurons, including the N-methyl-D-aspartate receptor, are generally higher on the dendrites than on the soma. Further, these results are similar to those obtained from dorsal horn neurons grown in culture.

Overexpression of hypoxia-inducible factor 1 alpha improves immunomodulation by dental mesenchymal stem cells.

PubMed

Martinez, Victor G; Ontoria-Oviedo, Imelda; Ricardo, Carolina P; Harding, Sian E; Sacedon, Rosa; Varas, Alberto; Zapata, Agustin; Sepulveda, Pilar; Vicente, Angeles

2017-09-29

Human dental mesenchymal stem cells (MSCs) are considered as highly accessible and attractive MSCs for use in regenerative medicine, yet some of their features are not as well characterized as other MSCs. Hypoxia-preconditioning and hypoxia-inducible factor 1 (HIF-1) alpha overexpression significantly improves MSC therapeutics, but the mechanisms involved are not fully understood. In the present study, we characterize immunomodulatory properties of dental MSCs and determine changes in their ability to modulate adaptive and innate immune populations after HIF-1 alpha overexpression. Human dental MSCs were stably transduced with green fluorescent protein (GFP-MSCs) or GFP-HIF-1 alpha lentivirus vectors (HIF-MSCs). A hypoxic-like metabolic profile was confirmed by mitochondrial and glycolysis stress test. Capacity of HIF-MSCs to modulate T-cell activation, dendritic cell differentiation, monocyte migration, and polarizations towards macrophages and natural killer (NK) cell lytic activity was assessed by a number of functional assays in co-cultures. The expression of relevant factors were determined by polymerase chain reaction (PCR) analysis and enzyme-linked immunosorbent assay (ELISA). While HIF-1 alpha overexpression did not modify the inhibition of T-cell activation by MSCs, HIF-MSCs impaired dendritic cell differentiation more efficiently. In addition, HIF-MSCs showed a tendency to induce higher attraction of monocytes, which differentiate into suppressor macrophages, and exhibited enhanced resistance to NK cell-mediated lysis, which supports the improved therapeutic capacity of HIF-MSCs. HIF-MSCs also displayed a pro-angiogenic profile characterized by increased expression of CXCL12/SDF1 and CCL5/RANTES and complete loss of CXCL10/IP10 transcription. Immunomodulation and expression of trophic factors by dental MSCs make them perfect candidates for cell therapy. Overexpression of HIF-1 alpha enhances these features and increases their resistance to allogenic NK cell lysis and, hence, their potential in vivo lifespan. Our results further support the use of HIF-1 alpha-expressing dental MSCs for cell therapy in tissue injury and immune disorders.

Semi-allogeneic dendritic cells can induce antigen-specific T-cell activation, which is not enhanced by concurrent alloreactivity.

PubMed

Wells, James W; Cowled, Chris J; Darling, David; Guinn, Barbara-Ann; Farzaneh, Farzin; Noble, Alistair; Galea-Lauri, Joanna

2007-12-01

Alloreactive T-cell responses are known to result in the production of large amounts of proinflammatory cytokines capable of activating and maturing dendritic cells (DC). However, it is unclear whether these allogeneic responses could also act as an adjuvant for concurrent antigen-specific responses. To examine effects of simultaneous alloreactive and antigen-specific T-cell responses induced by semi-allogeneic DC. Semi-allogeneic DC were generated from the F(1) progeny of inbred strains of mice (C57BL/6 and C3H, or C57BL/6 and DBA). We directly primed antigen-specific CD8(+) and CD4(+) T-cells from OT-I and OT-II mice, respectively, in the absence of allogeneic responses, in vitro, and in the presence or absence of alloreactivity in vivo. In vitro, semi-allogeneic DC cross-presented ovalbumin (OVA) to naïve CD8(+) OT-I transgenic T-cells, primed naïve CD4(+) OT-II transgenic T-cells and could stimulate strong alloreactive T-cell proliferation in a primary mixed lymphocyte reaction (MLR). In vivo, semi-allogeneic DC migrated efficiently to regional lymph nodes but did not survive there as long as autologous DC. In addition, they were not able to induce cytotoxic T-lymphocyte (CTL) activity to a target peptide, and only weakly stimulated adoptively transferred OT-II cells. The CD4(+) response was unchanged in allo-tolerized mice, indicating that alloreactive T-cell responses could not provide help for concurrently activated antigen-specific responses. In an EL4 tumour-treatment model, vaccination with semi-allogeneic DC/EL4 fusion hybrids, but not allogeneic DC/EL4 hybrids, significantly increased mouse survival. Expression of self-Major histocompatibility complex (MHC) by semi-allogeneic DC can cause the induction of antigen-specific immunity, however, concurrently activated allogeneic bystander responses do not provide helper or adjuvant effects.

Retinal ganglion cell dendritic fields in old-world monkeys are oriented radially.

PubMed

Schall, J D; Perry, V H; Leventhal, A G

1986-03-12

We analyzed the dendritic field morphology of 297 ganglion cells from peripheral regions of monkey retina. Most of the dendritic fields were elongated, and there was a significant tendency for the dendritic fields to be oriented radially, i.e., like the spokes of a wheel with the fovea at the hub. An overrepresentation of radial orientations in the peripheral retina of primates might explain why humans are best able to detect stimuli which are oriented radially using peripheral vision.

Efficient priming of CD4 T cells by Langerin-expressing dendritic cells targeted with porcine epidemic diarrhea virus spike protein domains in pigs.

PubMed

Subramaniam, Sakthivel; Cao, Dianjun; Tian, Debin; Cao, Qian M; Overend, Christopher; Yugo, Danielle M; Matzinger, Shannon R; Rogers, Adam J; Heffron, C Lynn; Catanzaro, Nicholas; Kenney, Scott P; Opriessnig, Tanja; Huang, Yao-Wei; Labarque, Geoffrey; Wu, Stephen Q; Meng, Xiang-Jin

2017-01-02

Porcine epidemic diarrhea virus (PEDV) first emerged in the United States in 2013 causing high mortality and morbidity in neonatal piglets with immense economic losses to the swine industry. PEDV is an alpha-coronavirus replicating primarily in porcine intestinal cells. PEDV vaccines are available in Asia and Europe, and conditionally-licensed vaccines recently became available in the United States but the efficacies of these vaccines in eliminating PEDV from swine populations are questionable. In this study, the immunogenicity of a subunit vaccine based on the spike protein of PEDV, which was directly targeted to porcine dendritic cells (DCs) expressing Langerin, was assessed. The PEDV S antigen was delivered to the dendritic cells through a single-chain antibody specific to Langerin and the targeted cells were stimulated with cholera toxin adjuvant. This approach, known as "dendritic cell targeting," greatly improved PEDV S antigen-specific T cell interferon-γ responses in the CD4 pos CD8 pos T cell compartment in pigs as early as 7days upon transdermal administration. When the vaccine protein was targeted to Langerin pos DCs systemically through intramuscular vaccination, it induced higher serum IgG and IgA responses in pigs, though these responses require a booster dose, and the magnitude of T cell responses were lower as compared to transdermal vaccination. We conclude that PEDV spike protein domains targeting Langerin-expressing dendritic cells significantly increased CD4 T cell immune responses in pigs. The results indicate that the immunogenicity of protein subunit vaccines can be greatly enhanced by direct targeting of the vaccine antigens to desirable dendritic cell subsets in pigs. Copyright © 2016 Elsevier B.V. All rights reserved.

Dendritic excitability modulates dendritic information processing in a purkinje cell model.

PubMed

Coop, Allan D; Cornelis, Hugo; Santamaria, Fidel

2010-01-01

Using an electrophysiological compartmental model of a Purkinje cell we quantified the contribution of individual active dendritic currents to processing of synaptic activity from granule cells. We used mutual information as a measure to quantify the information from the total excitatory input current (I(Glu)) encoded in each dendritic current. In this context, each active current was considered an information channel. Our analyses showed that most of the information was encoded by the calcium (I(CaP)) and calcium activated potassium (I(Kc)) currents. Mutual information between I(Glu) and I(CaP) and I(Kc) was sensitive to different levels of excitatory and inhibitory synaptic activity that, at the same time, resulted in the same firing rate at the soma. Since dendritic excitability could be a mechanism to regulate information processing in neurons we quantified the changes in mutual information between I(Glu) and all Purkinje cell currents as a function of the density of dendritic Ca (g(CaP)) and Kca (g(Kc)) conductances. We extended our analysis to determine the window of temporal integration of I(Glu) by I(CaP) and I(Kc) as a function of channel density and synaptic activity. The window of information integration has a stronger dependence on increasing values of g(Kc) than on g(CaP), but at high levels of synaptic stimulation information integration is reduced to a few milliseconds. Overall, our results show that different dendritic conductances differentially encode synaptic activity and that dendritic excitability and the level of synaptic activity regulate the flow of information in dendrites.

Con-nectin axons and dendrites.

PubMed

Beaudoin, Gerard M J

2006-07-03

Unlike adherens junctions, synapses are asymmetric connections, usually between axons and dendrites, that rely on various cell adhesion molecules for structural stability and function. Two cell types of adhesion molecules found at adherens junctions, cadherins and nectins, are thought to mediate homophilic interaction between neighboring cells. In this issue, Togashi et al. (see p. 141) demonstrate that the differential localization of two heterophilic interacting nectins mediates the selective attraction of axons and dendrites in cooperation with cadherins.

Frequency of Dendritic Cells and Their Expression of Costimulatory Molecules in Children with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Saad, Khaled; Zahran, Asmaa M.; Elsayh, Khalid I.; Abdel-Rahman, Ahmed A.; Al-Atram, Abdulrahman A.; Hussein, Almontaser; El-Gendy, Yasmin G.

2017-01-01

The aim of our study was to evaluate the frequencies of myeloid dendritic cells (mDCs) and plasmacytoid dendritic cells (pDCs) in children with ASD. Subjects were 32 children with ASD and 30 healthy children as controls. The numbers of mDCs and pDCs and the expression of CD86 and CD80 on the entire DCs were detected by flow cytometry. ASD children…

Neutrophils, dendritic cells and Toxoplasma.

PubMed

Denkers, Eric Y; Butcher, Barbara A; Del Rio, Laura; Bennouna, Soumaya

2004-03-09

Toxoplasma gondii rapidly elicits strong Type 1 cytokine-based immunity. The necessity for this response is well illustrated by the example of IFN-gamma and IL-12 gene knockout mice that rapidly succumb to the effects of acute infection. The parasite itself is skilled at sparking complex interactions in the innate immune system that lead to protective immunity. Neutrophils are one of the first cell types to arrive at the site of infection, and the cells release several proinflammatory cytokines and chemokines in response to Toxoplasma. Dendritic cells are an important source of IL-12 during infection with T. gondii and other microbial pathogens, and they are also specialized for high-level antigen presentation to T lymphocytes. Tachyzoites express at least two types of molecules that trigger innate immune cell cytokine production. One of these involves Toll-like receptor/MyD88 pathways common to many microbial pathogens. The second pathway is less conventional and involves molecular mimicry between a parasite cyclophilin and host CC chemokine receptor 5-binding ligands. Neutrophils, dendritic cells and Toxoplasma work together to elicit the immune response required for host survival. Cytokine and chemokine cross-talk between parasite-triggered neutrophils and dendritic cells results in recruitment, maturation and activation of the latter. Neutrophil-empowered dendritic cells possess properties expected of highly potent antigen presenting cells that drive T helper 1 generation.

Presence and regulation of the endocannabinoid system in human dendritic cells.

PubMed

Matias, Isabel; Pochard, Pierre; Orlando, Pierangelo; Salzet, Michel; Pestel, Joel; Di Marzo, Vincenzo

2002-08-01

Cannabinoid receptors and their endogenous ligands, the endocannabinoids, have been detected in several blood immune cells, including monocytes/macrophages, basophils and lymphocytes. However, their presence in dendritic cells, which play a key role in the initiation and development of the immune response, has never been investigated. Here we have analyzed human dendritic cells for the presence of the endocannabinoids, anandamide and 2-arachidonoylglycerol (2-AG), the cannabinoid CB1 and CB2 receptors, and one of the enzymes mostly responsible for endocannabinoid hydrolysis, the fatty acid amide hydrolase (FAAH). By using a very sensitive liquid chromatography-atmospheric pressure chemical ionization-mass spectrometric (LC-APCI-MS) method, lipids extracted from immature dendritic cells were shown to contain 2-AG, anandamide and the anti-inflammatory anandamide congener, N-palmitoylethanolamine (PalEtn) (2.1 +/- 1.0, 0.14 +/- 0.02 and 8.2 +/- 3.9 pmol x 10(-7) cells, respectively). The amounts of 2-AG, but not anandamide or PalEtn, were significantly increased following cell maturation induced by bacterial lipopolysaccharide (LPS) or the allergen Der p 1 (2.8- and 1.9-fold, respectively). By using both RT-PCR and Western immunoblotting, dendritic cells were also found to express measurable amounts of CB1 and CB2 receptors and of FAAH. Cell maturation did not consistently modify the expression of these proteins, although in some cell preparations a decrease of the levels of both CB1 and CB2 mRNA transcripts was observed after LPS stimulation. These findings demonstrate for the first time that the endogenous cannabinoid system is present in human dendritic cells and can be regulated by cell activation.

Cellular and dendritic growth in a binary melt - A marginal stability approach

NASA Technical Reports Server (NTRS)

Laxmanan, V.

1986-01-01

A simple model for the constrained growth of an array of cells or dendrites in a binary alloy in the presence of an imposed positive temperature gradient in the liquid is proposed, with the dendritic or cell tip radius calculated using the marginal stability criterion of Langer and Muller-Krumbhaar (1977). This approach, an approach adopting the ad hoc assumption of minimum undercooling at the cell or dendrite tip, and an approach based on the stability criterion of Trivedi (1980) all predict tip radii to within 30 percent of each other, and yield a simple relationship between the tip radius and the growth conditions. Good agreement is found between predictions and data obtained in a succinonitrile-acetone system, and under the present experimental conditions, the dendritic tip stability parameter value is found to be twice that obtained previously, possibly due to a transition in morphology from a cellular structure with just a few side branches, to a more fully developed dendritic structure.

A dendrite-autonomous mechanism for direction selectivity in retinal starburst amacrine cells.

PubMed

Hausselt, Susanne E; Euler, Thomas; Detwiler, Peter B; Denk, Winfried

2007-07-01

Detection of image motion direction begins in the retina, with starburst amacrine cells (SACs) playing a major role. SACs generate larger dendritic Ca(2+) signals when motion is from their somata towards their dendritic tips than for motion in the opposite direction. To study the mechanisms underlying the computation of direction selectivity (DS) in SAC dendrites, electrical responses to expanding and contracting circular wave visual stimuli were measured via somatic whole-cell recordings and quantified using Fourier analysis. Fundamental and, especially, harmonic frequency components were larger for expanding stimuli. This DS persists in the presence of GABA and glycine receptor antagonists, suggesting that inhibitory network interactions are not essential. The presence of harmonics indicates nonlinearity, which, as the relationship between harmonic amplitudes and holding potential indicates, is likely due to the activation of voltage-gated channels. [Ca(2+)] changes in SAC dendrites evoked by voltage steps and monitored by two-photon microscopy suggest that the distal dendrite is tonically depolarized relative to the soma, due in part to resting currents mediated by tonic glutamatergic synaptic input, and that high-voltage-activated Ca(2+) channels are active at rest. Supported by compartmental modeling, we conclude that dendritic DS in SACs can be computed by the dendrites themselves, relying on voltage-gated channels and a dendritic voltage gradient, which provides the spatial asymmetry necessary for direction discrimination.

Human innate lymphoid cells (ILCs) in filarial infections.

PubMed

Bonne-Année, S; Nutman, T B

2018-02-01

Filarial infections are characteristically chronic and can cause debilitating diseases governed by parasite-induced innate and adaptive immune responses. Filarial parasites traverse or establish niches in the skin (migrating infective larvae), in nonmucosal tissues (adult parasite niche) and in the blood or skin (circulating microfilariae) where they intersect with the host immune response. While several studies have demonstrated that filarial parasites and their antigens can modulate myeloid cells (monocyte, macrophage and dendritic cell subsets), T- and B-lymphocytes and skin resident cell populations, the role of innate lymphoid cells during filarial infections has only recently emerged. Despite the identification and characterization of innate lymphoid cells (ILCs) in murine helminth infections, little is actually known about the role of human ILCs during parasitic infections. The focus of this review will be to highlight the composition of ILCs in the skin, lymphatics and blood; where the host-parasite interaction is well-defined and to examine the role of ILCs during filarial infections. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Adult Langerhans cells derive predominantly from embryonic fetal liver monocytes with a minor contribution of yolk sac-derived macrophages.

PubMed

Hoeffel, Guillaume; Wang, Yilin; Greter, Melanie; See, Peter; Teo, Pearline; Malleret, Benoit; Leboeuf, Marylène; Low, Donovan; Oller, Guillaume; Almeida, Francisca; Choy, Sharon H Y; Grisotto, Marcos; Renia, Laurent; Conway, Simon J; Stanley, E Richard; Chan, Jerry K Y; Ng, Lai Guan; Samokhvalov, Igor M; Merad, Miriam; Ginhoux, Florent

2012-06-04

Langerhans cells (LCs) are the dendritic cells (DCs) of the epidermis, forming one of the first hematopoietic lines of defense against skin pathogens. In contrast to other DCs, LCs arise from hematopoietic precursors that seed the skin before birth. However, the origin of these embryonic precursors remains unclear. Using in vivo lineage tracing, we identify a first wave of yolk sac (YS)-derived primitive myeloid progenitors that seed the skin before the onset of fetal liver hematopoiesis. YS progenitors migrate to the embryo proper, including the prospective skin, where they give rise to LC precursors, and the brain rudiment, where they give rise to microglial cells. However, in contrast to microglia, which remain of YS origin throughout life, YS-derived LC precursors are largely replaced by fetal liver monocytes during late embryogenesis. Consequently, adult LCs derive predominantly from fetal liver monocyte-derived cells with a minor contribution of YS-derived cells. Altogether, we establish that adult LCs have a dual origin, bridging early embryonic and late fetal myeloid development.

Adult Langerhans cells derive predominantly from embryonic fetal liver monocytes with a minor contribution of yolk sac–derived macrophages

PubMed Central

Hoeffel, Guillaume; Wang, Yilin; Greter, Melanie; See, Peter; Teo, Pearline; Malleret, Benoit; Leboeuf, Marylène; Low, Donovan; Oller, Guillaume; Almeida, Francisca; Choy, Sharon H.Y.; Grisotto, Marcos; Renia, Laurent; Conway, Simon J.; Stanley, E. Richard; Chan, Jerry K.Y.; Ng, Lai Guan; Samokhvalov, Igor M.

2012-01-01

Langerhans cells (LCs) are the dendritic cells (DCs) of the epidermis, forming one of the first hematopoietic lines of defense against skin pathogens. In contrast to other DCs, LCs arise from hematopoietic precursors that seed the skin before birth. However, the origin of these embryonic precursors remains unclear. Using in vivo lineage tracing, we identify a first wave of yolk sac (YS)–derived primitive myeloid progenitors that seed the skin before the onset of fetal liver hematopoiesis. YS progenitors migrate to the embryo proper, including the prospective skin, where they give rise to LC precursors, and the brain rudiment, where they give rise to microglial cells. However, in contrast to microglia, which remain of YS origin throughout life, YS-derived LC precursors are largely replaced by fetal liver monocytes during late embryogenesis. Consequently, adult LCs derive predominantly from fetal liver monocyte-derived cells with a minor contribution of YS-derived cells. Altogether, we establish that adult LCs have a dual origin, bridging early embryonic and late fetal myeloid development. PMID:22565823

Histopathology of human superficial herpes simplex keratitis.

PubMed Central

Maudgal, P. C.; Missotten, L.

1978-01-01

In vivo corneal replicas were made in 20 cases of patients with superficial dendritic ulcers of the cornea. Histopathological study of the replicas and superficial epithelial cells showed that the dendrites are composed of rounded epithelial cells and variable sized syncytia containing bizarre shaped nuclei. Pseudopodia-like processes containing DNA and some RNA extend from the syncytia into the surrounding epithelial cells, which on coming into contact with these processes become rounded and liquefied to give rise to another syncytium. The epithelial cells adjacent to the dendrite and elongated and usually orientated parallel to the long axis of the lesion. Surrounding the terminal bulbs, they are disposed in an arcuate fashion. These cells show C-mitotic lesions, intranuclear and cytoplasmic inclusion bodies, and polykaryocyte formation. Microscopic examination of the corneal replicas shows the intranuclear lesions and rounding of cells up to about 2 mm away from the dendritic ulcers. These areas appear normal on clinical examination. Images PMID:629910

Identification of a dendritic cell receptor that couples sensing of necrosis to immunity.

PubMed

Sancho, David; Joffre, Olivier P; Keller, Anna M; Rogers, Neil C; Martínez, Dolores; Hernanz-Falcón, Patricia; Rosewell, Ian; Reis e Sousa, Caetano

2009-04-16

Injury or impaired clearance of apoptotic cells leads to the pathological accumulation of necrotic corpses, which induce an inflammatory response that initiates tissue repair. In addition, antigens present in necrotic cells can sometimes provoke a specific immune response and it has been argued that necrosis could explain adaptive immunity in seemingly infection-free situations, such as after allograft transplantation or in spontaneous and therapy-induced tumour rejection. In the mouse, the CD8alpha+ subset of dendritic cells phagocytoses dead cell remnants and cross-primes CD8+ T cells against cell-associated antigens. Here we show that CD8alpha+ dendritic cells use CLEC9A (also known as DNGR-1), a recently-characterized C-type lectin, to recognize a preformed signal that is exposed on necrotic cells. Loss or blockade of CLEC9A does not impair the uptake of necrotic cell material by CD8+ dendritic cells, but specifically reduces cross-presentation of dead-cell-associated antigens in vitro and decreases the immunogenicity of necrotic cells in vivo. The function of CLEC9A requires a key tyrosine residue in its intracellular tail that allows the recruitment and activation of the tyrosine kinase SYK, which is also essential for cross-presentation of dead-cell-associated antigens. Thus, CLEC9A functions as a SYK-coupled C-type lectin receptor to mediate sensing of necrosis by the principal dendritic-cell subset involved in regulating cross-priming to cell-associated antigens.

Existence of CD8α-like dendritic cells with a conserved functional specialization and a common molecular signature in distant mammalian species.

PubMed

Contreras, Vanessa; Urien, Céline; Guiton, Rachel; Alexandre, Yannick; Vu Manh, Thien-Phong; Andrieu, Thibault; Crozat, Karine; Jouneau, Luc; Bertho, Nicolas; Epardaud, Mathieu; Hope, Jayne; Savina, Ariel; Amigorena, Sebastian; Bonneau, Michel; Dalod, Marc; Schwartz-Cornil, Isabelle

2010-09-15

The mouse lymphoid organ-resident CD8alpha(+) dendritic cell (DC) subset is specialized in Ag presentation to CD8(+) T cells. Recent evidence shows that mouse nonlymphoid tissue CD103(+) DCs and human blood DC Ag 3(+) DCs share similarities with CD8alpha(+) DCs. We address here whether the organization of DC subsets is conserved across mammals in terms of gene expression signatures, phenotypic characteristics, and functional specialization, independently of the tissue of origin. We study the DC subsets that migrate from the skin in the ovine species that, like all domestic animals, belongs to the Laurasiatheria, a distinct phylogenetic clade from the supraprimates (human/mouse). We demonstrate that the minor sheep CD26(+) skin lymph DC subset shares significant transcriptomic similarities with mouse CD8alpha(+) and human blood DC Ag 3(+) DCs. This allowed the identification of a common set of phenotypic characteristics for CD8alpha-like DCs in the three mammalian species (i.e., SIRP(lo), CADM1(hi), CLEC9A(hi), CD205(hi), XCR1(hi)). Compared to CD26(-) DCs, the sheep CD26(+) DCs show 1) potent stimulation of allogeneic naive CD8(+) T cells with high selective induction of the Ifngamma and Il22 genes; 2) dominant efficacy in activating specific CD8(+) T cells against exogenous soluble Ag; and 3) selective expression of functional pathways associated with high capacity for Ag cross-presentation. Our results unravel a unifying definition of the CD8alpha(+)-like DCs across mammalian species and identify molecular candidates that could be used for the design of vaccines applying to mammals in general.

CXCL4 Exposure Potentiates TLR-Driven Polarization of Human Monocyte-Derived Dendritic Cells and Increases Stimulation of T Cells.

PubMed

Silva-Cardoso, Sandra C; Affandi, Alsya J; Spel, Lotte; Cossu, Marta; van Roon, Joel A G; Boes, Marianne; Radstake, Timothy R D J

2017-07-01

Chemokines have been shown to play immune-modulatory functions unrelated to steering cell migration. CXCL4 is a chemokine abundantly produced by activated platelets and immune cells. Increased levels of circulating CXCL4 are associated with immune-mediated conditions, including systemic sclerosis. Considering the central role of dendritic cells (DCs) in immune activation, in this article we addressed the effect of CXCL4 on the phenotype and function of monocyte-derived DCs (moDCs). To this end, we compared innate and adaptive immune responses of moDCs with those that were differentiated in the presence of CXCL4. Already prior to TLR- or Ag-specific stimulation, CXCL4-moDCs displayed a more matured phenotype. We found that CXCL4 exposure can sensitize moDCs for TLR-ligand responsiveness, as illustrated by a dramatic upregulation of CD83, CD86, and MHC class I in response to TLR3 and TLR7/8-agonists. Also, we observed a markedly increased secretion of IL-12 and TNF-α by CXCL4-moDCs exclusively upon stimulation with polyinosinic-polycytidylic acid, R848, and CL075 ligands. Next, we analyzed the effect of CXCL4 in modulating DC-mediated T cell activation. CXCL4-moDCs strongly potentiated proliferation of autologous CD4 + T cells and CD8 + T cells and production of IFN-γ and IL-4, in an Ag-independent manner. Although the internalization of Ag was comparable to that of moDCs, Ag processing by CXCL4-moDCs was impaired. Yet, these cells were more potent at stimulating Ag-specific CD8 + T cell responses. Together our data support that increased levels of circulating CXCL4 may contribute to immune dysregulation through the modulation of DC differentiation. Copyright © 2017 by The American Association of Immunologists, Inc.

Maximization of the connectivity repertoire as a statistical principle governing the shapes of dendritic arbors

PubMed Central

Wen, Quan; Stepanyants, Armen; Elston, Guy N.; Grosberg, Alexander Y.; Chklovskii, Dmitri B.

2009-01-01

The shapes of dendritic arbors are fascinating and important, yet the principles underlying these complex and diverse structures remain unclear. Here, we analyzed basal dendritic arbors of 2,171 pyramidal neurons sampled from mammalian brains and discovered 3 statistical properties: the dendritic arbor size scales with the total dendritic length, the spatial correlation of dendritic branches within an arbor has a universal functional form, and small parts of an arbor are self-similar. We proposed that these properties result from maximizing the repertoire of possible connectivity patterns between dendrites and surrounding axons while keeping the cost of dendrites low. We solved this optimization problem by drawing an analogy with maximization of the entropy for a given energy in statistical physics. The solution is consistent with the above observations and predicts scaling relations that can be tested experimentally. In addition, our theory explains why dendritic branches of pyramidal cells are distributed more sparsely than those of Purkinje cells. Our results represent a step toward a unifying view of the relationship between neuronal morphology and function. PMID:19622738

miR-451 regulates dendritic cell cytokine responses to influenza infection1

PubMed Central

Rosenberger, Carrie M.; Podyminogin, Rebecca L.; Navarro, Garnet; Zhao, Guo-Wei; Askovich, Peter S.; Weiss, Mitchell J.; Aderem, Alan

2012-01-01

MicroRNAs are important post-transcriptional regulators in immune cells, but how viral infection regulates microRNA expression to shape dendritic cell responses has not been well characterized. We identified 20 miRNAs that were differentially expressed in primary murine dendritic cells in response to the double-stranded RNA agonist poly(I:C), a subset of which were modestly regulated by influenza infection. miR-451 was unique because it was induced more strongly in primary splenic and lung dendritic cells by live viral infection than by purified agonists of pattern recognition receptors. We determined that miR-451 regulates a subset of pro-inflammatory cytokine responses. Three types of primary dendritic cells treated with anti-sense RNA antagomirs directed against miR-451 secreted elevated levels of IL-6, TNF, CCL5/RANTES, and CCL3/MIP1α, and these results were confirmed using miR-451null cells. miR-451 negatively regulates YWHAZ/14-3-3ζ protein levels in various cell types, and we measured a similar inhibition of YWHAZ levels in dendritic cells. It is known that YWHAZ can control the activity of two negative regulators of cytokine production: FOXO3, which is an inhibitory transcription factor, and ZFP36/Tristetraprolin, which binds to AU-rich elements within 3′-UTRs to destabilize cytokine mRNAs. Inhibition of miR-451 expression correlated with increased YWHAZ protein expression and decreased ZFP36 expression, providing a possible mechanism for the elevated secretion of IL-6, TNF, CCL5/RANTES, and CCL3/MIP1α. miR-451 levels are themselves increased by IL-6 and type I interferon, potentially forming a regulatory loop. These data suggest that viral infection specifically induces a miRNA that directs a negative regulatory cascade to tune dendritic cell cytokine production. PMID:23169590

Dendrodendritic Synapses in the Mouse Olfactory Bulb External Plexiform Layer

PubMed Central

Bartel, Dianna L.; Rela, Lorena; Hsieh, Lawrence; Greer, Charles A.

2014-01-01

Odor information relayed by olfactory bulb projection neurons, mitral and tufted cells (M/T), is modulated by pairs of reciprocal dendrodendritic synaptic circuits in the external plexiform layer (EPL). Interneurons, which are accounted for largely by granule cells, receive depolarizing input from M/T dendrites and in turn inhibit current spread in M/T dendrites via hyperpolarizing reciprocal dendrodendritic synapses. Because the location of dendrodendritic synapses may significantly affect the cascade of odor information, we assessed synaptic properties and density within sublaminae of the EPL and along the length of M/T secondary dendrites. In electron micrographs the M/T to granule cell synapse appeared to predominate and were equivalent in both the outer and inner EPL. However, the dendrodendritic synapses from granule cell spines onto M/T dendrites, were more prevalent in the outer EPL. In contrast, individual gephyrin-IR puncta, a postsynaptic scaffolding protein at inhibitory synapses used here as a proxy for the granule to M/T dendritic synapse was equally distributed throughout the EPL. Of significance to the organization of intrabulbar circuits, gephyrin-IR synapses are not uniformly distributed along M/T secondary dendrites. Synaptic density, expressed as a function of surface area, increases distal to the cell body. Furthermore, the distributions of gephyrin-IR puncta are heterogeneous and appear as clusters along the length of the M/T dendrites. Consistent with computational models, our data suggest that temporal coding in M/T cells is achieved by precisely located inhibitory input and that distance from the soma is compensated with an increase in synaptic density. PMID:25420934

Transcriptional Changes during Naturally Acquired Zika Virus Infection Render Dendritic Cells Highly Conducive to Viral Replication.

PubMed

Sun, Xiaoming; Hua, Stephane; Chen, Hsiao-Rong; Ouyang, Zhengyu; Einkauf, Kevin; Tse, Samantha; Ard, Kevin; Ciaranello, Andrea; Yawetz, Sigal; Sax, Paul; Rosenberg, Eric S; Lichterfeld, Mathias; Yu, Xu G

2017-12-19

Although dendritic cells are among the human cell population best equipped for cell-intrinsic antiviral immune defense, they seem highly susceptible to infection with the Zika virus (ZIKV). Using highly purified myeloid dendritic cells isolated from individuals with naturally acquired acute infection, we here show that ZIKV induces profound perturbations of transcriptional signatures relative to healthy donors. Interestingly, we noted a remarkable downregulation of antiviral interferon-stimulated genes and innate immune sensors, suggesting that ZIKV can actively suppress interferon-dependent immune responses. In contrast, several host factors known to support ZIKV infection were strongly upregulated during natural ZIKV infection; these transcripts included AXL, the main entry receptor for ZIKV; SOCS3, a negative regulator of ISG expression; and IDO-1, a recognized inducer of regulatory T cell responses. Thus, during in vivo infection, ZIKV can transform the transcriptome of dendritic cells in favor of the virus to render these cells highly conducive to ZIKV infection. Published by Elsevier Inc.

Control of axonal sprouting and dendrite branching by the Nrg-Ank complex at the neuron-glia interface.

PubMed

Yamamoto, Misato; Ueda, Ryu; Takahashi, Kuniaki; Saigo, Kaoru; Uemura, Tadashi

2006-08-22

Neurons are highly polarized cells with distinct subcellular compartments, including dendritic arbors and an axon. The proper function of the nervous system relies not only on correct targeting of axons, but also on development of neuronal-class-specific geometry of dendritic arbors [1-4]. To study the intercellular control of the shaping of dendritic trees in vivo, we searched for cell-surface proteins expressed by Drosophila dendritic arborization (da) neurons [5-7]. One of them was Neuroglian (Nrg), a member of the Ig superfamily ; Nrg and vertebrate L1-family molecules have been implicated in various aspects of neuronal wiring, such as axon guidance, axonal myelination, and synapse formation [9-12]. A subset of the da neurons in nrg mutant embryos exhibited deformed dendritic arbors and abnormal axonal sprouting. Our functional analysis in a cell-type-selective manner strongly suggested that those da neurons employed Nrg to interact with the peripheral glia for suppressing axonal sprouting and for forming second-order dendritic branches. At least for the former role, Nrg functioned in concert with the intracellular adaptor protein Ankyrin (Ank) [13]. Thus, the neuron-glia interaction that is mediated by Nrg, together with Ank under some situations, contributes to axonal and dendritic morphogenesis.

B lymphocyte lineage cells and the respiratory system

PubMed Central

Kato, Atsushi; Hulse, Kathryn E.; Tan, Bruce K.; Schleimer, Robert P.

2013-01-01

Adaptive humoral immune responses in the airways are mediated by B cells and plasma cells that express highly evolved and specific receptors and produce immunoglobulins of most isotypes. In some cases, such as autoimmune diseases or inflammatory diseases caused by excessive exposure to foreign antigens, these same immune cells can cause disease by virtue of overly vigorous responses. This review discusses the generation, differentiation, signaling, activation and recruitment pathways of B cells and plasma cells, with special emphasis on unique characteristics of subsets of these cells functioning within the respiratory system. The primary sensitization events that generate B cells responsible for effector responses throughout the airways usually occur in the upper airways, in tonsils and adenoid structures that make up Waldeyer’s Ring. Upon secondary exposure to antigen in the airways, antigen-processing dendritic cells migrate into secondary lymphoid organs such as lymph nodes that drain the upper and lower airways and further B cell expansion takes place at those sites. Antigen exposure in the upper or lower airways can also drive expansion of B lineage cells in the airway mucosal tissue and lead to the formation of inducible lymphoid follicles or aggregates that can mediate local immunity or disease. PMID:23540615

Regulated Assembly of Vacuolar ATPase Is Increased during Cluster Disruption-induced Maturation of Dendritic Cells through a Phosphatidylinositol 3-Kinase/mTOR-dependent Pathway*

PubMed Central

Liberman, Rachel; Bond, Sarah; Shainheit, Mara G.; Stadecker, Miguel J.; Forgac, Michael

2014-01-01

The vacuolar (H+)-ATPases (V-ATPases) are ATP-driven proton pumps composed of a peripheral V1 domain and a membrane-embedded V0 domain. Regulated assembly of V1 and V0 represents an important regulatory mechanism for controlling V-ATPase activity in vivo. Previous work has shown that V-ATPase assembly increases during maturation of bone marrow-derived dendritic cells induced by activation of Toll-like receptors. This increased assembly is essential for antigen processing, which is dependent upon an acidic lysosomal pH. Cluster disruption of dendritic cells induces a semi-mature phenotype associated with immune tolerance. Thus, semi-mature dendritic cells are able to process and present self-peptides to suppress autoimmune responses. We have investigated V-ATPase assembly in bone marrow-derived, murine dendritic cells and observed an increase in assembly following cluster disruption. This increased assembly is not dependent upon new protein synthesis and is associated with an increase in concanamycin A-sensitive proton transport in FITC-loaded lysosomes. Inhibition of phosphatidylinositol 3-kinase with wortmannin or mTORC1 with rapamycin effectively inhibits the increased assembly observed upon cluster disruption. These results suggest that the phosphatidylinositol 3-kinase/mTOR pathway is involved in controlling V-ATPase assembly during dendritic cell maturation. PMID:24273170

A Single Subset of Dendritic Cells Controls the Cytokine Bias of Natural Killer T Cell Responses to Diverse Glycolipid Antigens

PubMed Central

Arora, Pooja; Baena, Andres; Yu, Karl O.A.; Saini, Neeraj K.; Kharkwal, Shalu S.; Goldberg, Michael F.; Kunnath-Velayudhan, Shajo; Carreño, Leandro J.; Venkataswamy, Manjunatha M.; Kim, John; Lazar-Molnar, Eszter; Lauvau, Gregoire; Chang, Young-tae; Liu, Zheng; Bittman, Robert; Al-Shamkhani, Aymen; Cox, Liam R.; Jervis, Peter J.; Veerapen, Natacha; Besra, Gurdyal S.; Porcelli, Steven A.

2014-01-01

Summary Many hematopoietic cell types express CD1d and are capable of presenting glycolipid antigens to invariant natural killer T cells (iNKT cells). However, the question of which cells are the principal presenters of glycolipid antigens in vivo remains controversial, and it has been suggested that this might vary depending on the structure of a particular glycolipid antigen. Here we have shown that a single type of cell, the CD8α+ DEC-205+ dendritic cell, was mainly responsible for capturing and presenting a variety of different glycolipid antigens, including multiple forms of α-galactosylceramide that stimulate widely divergent cytokine responses. After glycolipid presentation, these dendritic cells rapidly altered their expression of various costimulatory and coinhibitory molecules in a manner that was dependent on the structure of the antigen. These findings show flexibility in the outcome of two-way communication between CD8α+ dendritic cells and iNKT cells, providing a mechanism for biasing toward either proinflammatory or anti-inflammatory responses. PMID:24412610

Synaptic integration in dendrites: exceptional need for speed

PubMed Central

Golding, Nace L; Oertel, Donata

2012-01-01

Some neurons in the mammalian auditory system are able to detect and report the coincident firing of inputs with remarkable temporal precision. A strong, low-voltage-activated potassium conductance (gKL) at the cell body and dendrites gives these neurons sensitivity to the rate of depolarization by EPSPs, allowing neurons to assess the coincidence of the rising slopes of unitary EPSPs. Two groups of neurons in the brain stem, octopus cells in the posteroventral cochlear nucleus and principal cells of the medial superior olive (MSO), extract acoustic information by assessing coincident firing of their inputs over a submillisecond timescale and convey that information at rates of up to 1000 spikes s−1. Octopus cells detect the coincident activation of groups of auditory nerve fibres by broadband transient sounds, compensating for the travelling wave delay by dendritic filtering, while MSO neurons detect coincident activation of similarly tuned neurons from each of the two ears through separate dendritic tufts. Each makes use of filtering that is introduced by the spatial distribution of inputs on dendrites. PMID:22930273

DSCAM-mediated control of dendritic and axonal arbor outgrowth enforces tiling and inhibits synaptic plasticity

PubMed Central

Simmons, Aaron B.; Bloomsburg, Samuel J.; Sukeena, Joshua M.; Miller, Calvin J.; Ortega-Burgos, Yohaniz; Borghuis, Bart G.

2017-01-01

Mature mammalian neurons have a limited ability to extend neurites and make new synaptic connections, but the mechanisms that inhibit such plasticity remain poorly understood. Here, we report that OFF-type retinal bipolar cells in mice are an exception to this rule, as they form new anatomical connections within their tiled dendritic fields well after retinal maturity. The Down syndrome cell-adhesion molecule (Dscam) confines these anatomical rearrangements within the normal tiled fields, as conditional deletion of the gene permits extension of dendrite and axon arbors beyond these borders. Dscam deletion in the mature retina results in expanded dendritic fields and increased cone photoreceptor contacts, demonstrating that DSCAM actively inhibits circuit-level plasticity. Electrophysiological recordings from Dscam−/− OFF bipolar cells showed enlarged visual receptive fields, demonstrating that expanded dendritic territories comprise functional synapses. Our results identify cell-adhesion molecule-mediated inhibition as a regulator of circuit-level neuronal plasticity in the adult retina. PMID:29114051

A Novel Heat Shock Protein 70-based Vaccine Prepared from DC-Tumor Fusion Cells.

PubMed

Weng, Desheng; Calderwood, Stuart K; Gong, Jianlin

2018-01-01

We have developed an enhanced molecular chaperone-based vaccine through rapid isolation of Hsp70 peptide complexes after the fusion of tumor and dendritic cells (Hsp70.PC-F). In this approach, the tumor antigens are introduced into the antigen processing machinery of dendritic cells through the cell fusion process and thus we can obtain antigenic tumor peptides or their intermediates that have been processed by dendritic cells. Our results show that Hsp70.PC-F has increased immunogenicity compared to preparations from tumor cells alone and therefore constitutes an improved formulation of chaperone protein-based tumor vaccine.

A comparative study of the microstructures observed in statically cast and continuously cast Bi-In-Sn ternary eutectic alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sengupta, S.; Soda, H.; McLean, A.

2000-01-01

A ternary eutectic alloy with a composition of 57.2 pct Bi, 24.8 pct In, and 18 pct Sn was continuously cast into wire of 2 mm diameter with casting speeds of 14 and 79 mm/min using the Ohno Continuous Casting (OCC) process. The microstructures obtained were compared with those of statically cast specimens. Extensive segregation of massive Bi blocks, Bi complex structures, and tin-rich dendrites was found in specimens that were statically cast. Decomposition of {radical}Sn by a eutectoid reaction was confirmed based on microstructural evidence. Ternary eutectic alloy with a cooling rate of approximately 1 C/min formed a doublemore » binary eutectic. The double binary eutectic consisted of regions of BiIn and decomposed {radical}Sn in the form of a dendrite cell structure and regions of Bi and decomposed {radical}Sn in the form of a complex-regular cell. The Bi complex-regular cells, which are a ternary eutectic constituent, existed either along the boundaries of the BiIn-decomposed {radical}Sn dendrite cells or at the front of elongated dendrite cell structures. In the continuously cast wires, primary Sn dendrites coupled with a small Bi phase were uniformly distributed within the Bi-In alloy matrix. Neither massive Bi phase, Bi complex-regular cells, no BiIn eutectic dendrite cells were observed, resulting in a more uniform microstructure in contrast to the heavily segregated structures of the statically cast specimens.« less

Distal gap junctions and active dendrites can tune network dynamics.

PubMed

Saraga, Fernanda; Ng, Leo; Skinner, Frances K

2006-03-01

Gap junctions allow direct electrical communication between CNS neurons. From theoretical and modeling studies, it is well known that although gap junctions can act to synchronize network output, they can also give rise to many other dynamic patterns including antiphase and other phase-locked states. The particular network pattern that arises depends on cellular, intrinsic properties that affect firing frequencies as well as the strength and location of the gap junctions. Interneurons or GABAergic neurons in hippocampus are diverse in their cellular characteristics and have been shown to have active dendrites. Furthermore, parvalbumin-positive GABAergic neurons, also known as basket cells, can contact one another via gap junctions on their distal dendrites. Using two-cell network models, we explore how distal electrical connections affect network output. We build multi-compartment models of hippocampal basket cells using NEURON and endow them with varying amounts of active dendrites. Two-cell networks of these model cells as well as reduced versions are explored. The relationship between intrinsic frequency and the level of active dendrites allows us to define three regions based on what sort of network dynamics occur with distal gap junction coupling. Weak coupling theory is used to predict the delineation of these regions as well as examination of phase response curves and distal dendritic polarization levels. We find that a nonmonotonic dependence of network dynamic characteristics (phase lags) on gap junction conductance occurs. This suggests that distal electrical coupling and active dendrite levels can control how sensitive network dynamics are to gap junction modulation. With the extended geometry, gap junctions located at more distal locations must have larger conductances for pure synchrony to occur. Furthermore, based on simulations with heterogeneous networks, it may be that one requires active dendrites if phase-locking is to occur in networks formed with distal gap junctions.

Role of the glucocorticoid-induced TNFR-related protein (GITR)-GITR ligand pathway in innate and adaptive immunity.

PubMed

Azuma, Miyuki

2010-01-01

Glucocorticoid-induced TNF receptor-related protein (GITR) is expressed in regulatory T cells at high levels, but is also inducible in conventional effector T cells after activation. Initial studies using an agonistic anti- GITR mAb mislead this line of research with respect to the contribution of GITR stimulation on the function of regulatory T cells. In fact, GITR acts as a costimulatory receptor for both effector and regulatory T cells by enhancing effector and regulatory functions, respectively. Unlike other costimulatory ligands, GITR ligand (GITRL) expression on mature myeloid dendritic cells (DCs) is extremely limited and the GITR-GITRL pathway does not contribute markedly to direct interactions with T cells and antigen-presenting cells in the secondary lymphoid tissues. Rather, GITRL is constitutively expressed on parenchymal tissue cells and interacts with GITR expressed on tissue-infiltrating macrophages and DCs, or effector and regulatory T cells. Interactions with GITR and GITRL at local inflammatory sites induce site-specific production of cytokines and chemokines, resulting in control activation of tissue-infiltrating effector or regulatory cells and their migration. This review summarizes recent reports on the GITR-GITRL pathway, which controls both innate and adaptive immune responses.

Functions of TGF-β-exposed plasmacytoid dendritic cells.

PubMed

Saas, Philippe; Perruche, Sylvain

2012-01-01

Plasmacytoid dendritic cells (pDCs) belong to the family of dendritic cells and possess specific features that distinguish them from conventional dendritic cells. For instance, pDC are the main interferon-alpha-secreting cells. Plasmacytoid dendritic cells exert both proinflammatory and regulatory functions. This is attested by the involvement of pDC through interferon-alpha secretion in several autoimmune diseases, and by the implication of pDC in tolerance. The same is true for TGF-β that plays a dual role in inflammation. In this review, we discuss recent data on pDC and TGF-β interactions. As with many cell types, pDCs are able to respond to TGF-β using the classic Smad signaling pathway. In addition, pDCs are capable to secrete TGF-β, in particular in response to TGF-β exposure. Exposure of pDCs to TGF-β prevents type I interferon secretion in response to TLR7/9 ligands. In contrast, the consequences of TGF-β on the antigen-presenting cell capacities of pDC are less clear, since TGF-β-exposed pDCs may lead to both regulatory T-cell and interleukin-17-secreting cell polarization. Here, we discuss the factors that may influence this polarization. We also discuss how pDCs exposed to TGF-β may participate in tolerance induction and maintenance, or, on the contrary, in autoimmune diseases.

Neuregulin 1 Deficiency Modulates Adolescent Stress-Induced Dendritic Spine Loss in a Brain Region-Specific Manner and Increases Complement 4 Expression in the Hippocampus.

PubMed

Clarke, David J; Chohan, Tariq W; Kassem, Mustafa S; Smith, Kristie L; Chesworth, Rose; Karl, Tim; Kuligowski, Michael P; Fok, Sandra Y; Bennett, Maxwell R; Arnold, Jonathon C

2018-03-16

One neuropathological feature of schizophrenia is a diminished number of dendritic spines in the prefrontal cortex and hippocampus. The neuregulin 1 (Nrg1) system is involved in the plasticity of dendritic spines, and chronic stress decreases dendritic spine densities in the prefrontal cortex and hippocampus. Here, we aimed to assess whether Nrg1 deficiency confers vulnerability to the effects of adolescent stress on dendritic spine plasticity. We also assessed other schizophrenia-relevant neurobiological changes such as microglial cell activation, loss of parvalbumin (PV) interneurons, and induction of complement factor 4 (C4). Adolescent male wild-type (WT) and Nrg1 heterozygous mice were subjected to chronic restraint stress before their brains underwent Golgi impregnation or immunofluorescent staining of PV interneurons, microglial cells, and C4. Stress in WT mice promoted dendritic spine loss and microglial cell activation in the prefrontal cortex and the hippocampus. However, Nrg1 deficiency rendered mice resilient to stress-induced dendritic spine loss in the infralimbic cortex and the CA3 region of the hippocampus without affecting stress-induced microglial cell activation in these brain regions. Nrg1 deficiency and adolescent stress combined to trigger increased dendritic spine densities in the prelimbic cortex. In the hippocampal CA1 region, Nrg1 deficiency accentuated stress-induced dendritic spine loss. Nrg1 deficiency increased C4 protein and decreased C4 mRNA expression in the hippocampus, and the number of PV interneurons in the basolateral amygdala. This study demonstrates that Nrg1 modulates the impact of stress on the adolescent brain in a region-specific manner. It also provides first evidence of a link between Nrg1 and C4 systems in the hippocampus.

Nanoparticles, [Gd@C82(OH)22]n, induces dendritic cell maturation and activates Th1 immune responses

PubMed Central

Yang, De; Zhao, Yuliang; Guo, Hua; Li, Yana; Tewary, Poonam; Xing, Gengmei; Hou, Wei; Oppenheim, Joost J.; Zhang, Ning

2010-01-01

Dendritic cells play a pivotal role in host immune defense, such as elimination of foreign pathogen and inhibition of tumorigenesis. In this paper, we report that [Gd@C82(OH)22]n could induce phenotypic maturation of dendritic cells by stimulating DC production of cytokines including IL-12p70, upregulating DC costimulatory (CD80, CD83, and CD86) and MHC (HLA-A,B,C and HLA-DR) molecules, and switching DCs from a CCL5-responsive to a CCL19-responsive phenotype. We found that [Gd@C82(OH)22]n can induce dendritic cells to become functionally mature as illustrated by their capacity to activate allogeneic T cells. Mice immunized with ovalbumin in the presence of [Gd@C82(OH)22]n exhibit enhanced ovalbumin-specific Th1-polarized immune response as evidenced by the predominantly increased production of IFNγ, IL-1β, and IL-2. The [Gd@C82(OH)22]n nanoparticle is a potent activator of dendritic cells and Th1 immune responses. These new findings also provide a rational understanding of the potent anticancer activities of [Gd@C82(OH)22]n nanoparticles reported previously. PMID:20121217

Pathogen-Sensing and Regulatory T Cells: Integrated Regulators of Immune Responses

PubMed Central

Grossman, Zvi; Paul, William E.

2014-01-01

We present the concept that pathogen-sensing and Tregs mutually regulate immune responses to conventional and tumor antigens through countervailing effects on dendritic cells. Normally, conventional CD4 T cells recognizing their cognate antigen-presented by a dendritic cell will respond only if the dendritic cell also receives a signal through its pathogen-sensing/ danger / adjuvant recognition systems (the pathogen-sensing triad). However, if Tregs capable of interacting with the same DC are absent, dendritic cells are competent to present antigens, both foreign and self, even without the stimulation provided by the pathogen-sensing triad. Tregs recognizing an antigen presented by the DC that is also presenting antigen to a conventional CD4 T cell will prevent such responses but a signal delivered by a member of the pathogen-sensing traid will overcome the Tregs’inhibitory action and will allow responses to go forward. These considerations take on special meaning for responses to “weak antigens” such as many of the antigens displayed by spontaneous human tumors. PMID:24894087

A reporter mouse model for in vivo tracing and in vitro molecular studies of melanocytic lineage cells and their diseases.

PubMed

Crawford, Melissa; Leclerc, Valerie; Dagnino, Lina

2017-08-15

Alterations in melanocytic lineage cells give rise to a plethora of distinct human diseases, including neurocristopathies, cutaneous pigmentation disorders, loss of vision and hearing, and melanoma. Understanding the ontogeny and biology of melanocytic cells, as well as how they interact with their surrounding environment, are key steps in the development of therapies for diseases that involve this cell lineage. Efforts to culture and characterize primary melanocytes from normal or genetically engineered mouse models have at times yielded contrasting observations. This is due, in part, to differences in the conditions used to isolate, purify and culture these cells in individual studies. By breeding ROSA mT/mG and Tyr::CreER T2 mice, we generated animals in which melanocytic lineage cells are identified through expression of green fluorescent protein. We also used defined conditions to systematically investigate the proliferation and migration responses of primary melanocytes on various extracellular matrix (ECM) substrates. Under our culture conditions, mouse melanocytes exhibit doubling times in the range of 10 days, and retain exponential proliferative capacity for 50-60 days. In culture, these melanocytes showed distinct responses to different ECM substrates. Specifically, laminin-332 promoted cell spreading, formation of dendrites, random motility and directional migration. In contrast, low or intermediate concentrations of collagen I promoted adhesion and acquisition of a bipolar morphology, and interfered with melanocyte forward movements. Our systematic evaluation of primary melanocyte responses emphasizes the importance of clearly defining culture conditions for these cells. This, in turn, is essential for the interpretation of melanocyte responses to extracellular cues and to understand the molecular basis of disorders involving the melanocytic cell lineage. © 2017. Published by The Company of Biologists Ltd.

A reporter mouse model for in vivo tracing and in vitro molecular studies of melanocytic lineage cells and their diseases

PubMed Central

Crawford, Melissa; Leclerc, Valerie

2017-01-01

ABSTRACT Alterations in melanocytic lineage cells give rise to a plethora of distinct human diseases, including neurocristopathies, cutaneous pigmentation disorders, loss of vision and hearing, and melanoma. Understanding the ontogeny and biology of melanocytic cells, as well as how they interact with their surrounding environment, are key steps in the development of therapies for diseases that involve this cell lineage. Efforts to culture and characterize primary melanocytes from normal or genetically engineered mouse models have at times yielded contrasting observations. This is due, in part, to differences in the conditions used to isolate, purify and culture these cells in individual studies. By breeding ROSAmT/mG and Tyr::CreERT2 mice, we generated animals in which melanocytic lineage cells are identified through expression of green fluorescent protein. We also used defined conditions to systematically investigate the proliferation and migration responses of primary melanocytes on various extracellular matrix (ECM) substrates. Under our culture conditions, mouse melanocytes exhibit doubling times in the range of 10 days, and retain exponential proliferative capacity for 50-60 days. In culture, these melanocytes showed distinct responses to different ECM substrates. Specifically, laminin-332 promoted cell spreading, formation of dendrites, random motility and directional migration. In contrast, low or intermediate concentrations of collagen I promoted adhesion and acquisition of a bipolar morphology, and interfered with melanocyte forward movements. Our systematic evaluation of primary melanocyte responses emphasizes the importance of clearly defining culture conditions for these cells. This, in turn, is essential for the interpretation of melanocyte responses to extracellular cues and to understand the molecular basis of disorders involving the melanocytic cell lineage. PMID:28642245

A β-Lactam Antibiotic Dampens Excitotoxic Inflammatory CNS Damage in a Mouse Model of Multiple Sclerosis

PubMed Central

Torres-Salazar, Delany; Bittner, Stefan; Zozulya, Alla L.; Weidenfeller, Christian; Kotsiari, Alexandra; Stangel, Martin; Fahlke, Christoph; Wiendl, Heinz

2008-01-01

In multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE), impairment of glial “Excitatory Amino Acid Transporters” (EAATs) together with an excess glutamate-release by invading immune cells causes excitotoxic damage of the central nervous system (CNS). In order to identify pathways to dampen excitotoxic inflammatory CNS damage, we assessed the effects of a β-lactam antibiotic, ceftriaxone, reported to enhance expression of glial EAAT2, in “Myelin Oligodendrocyte Glycoprotein” (MOG)-induced EAE. Ceftriaxone profoundly ameliorated the clinical course of murine MOG-induced EAE both under preventive and therapeutic regimens. However, ceftriaxone had impact neither on EAAT2 protein expression levels in several brain areas, nor on the radioactive glutamate uptake capacity in a mixed primary glial cell-culture and the glutamate-induced uptake currents in a mammalian cell line mediated by EAAT2. Moreover, the clinical effect of ceftriaxone was preserved in the presence of the EAAT2-specific transport inhibitor, dihydrokainate, while dihydrokainate alone caused an aggravated EAE course. This demonstrates the need for sufficient glial glutamate uptake upon an excitotoxic autoimmune inflammatory challenge of the CNS and a molecular target of ceftriaxone other than the glutamate transporter. Ceftriaxone treatment indirectly hampered T cell proliferation and proinflammatory INFγ and IL17 secretion through modulation of myelin-antigen presentation by antigen-presenting cells (APCs) e.g. dendritic cells (DCs) and reduced T cell migration into the CNS in vivo. Taken together, we demonstrate, that a β-lactam antibiotic attenuates disease course and severity in a model of autoimmune CNS inflammation. The mechanisms are reduction of T cell activation by modulation of cellular antigen-presentation and impairment of antigen-specific T cell migration into the CNS rather than or modulation of central glutamate homeostasis. PMID:18773080

CD22 Is Required for Protection against West Nile Virus Infection

PubMed Central

Ma, Daphne Y.; Suthar, Mehul S.; Kasahara, Shinji; Gale, Michael

2013-01-01

West Nile virus (WNV) is a RNA virus of the family Flaviviridae and the leading cause of mosquito-borne encephalitis in the United States. Humoral immunity is essential for protection against WNV infection; however, the requirements for initiating effective antibody responses against WNV infection are still unclear. CD22 (Siglec-2) is expressed on B cells and regulates B cell receptor signaling, cell survival, proliferation, and antibody production. In this study, we investigated how CD22 contributes to protection against WNV infection and found that CD22 knockout (Cd22−/−) mice were highly susceptible to WNV infection and had increased viral loads in the serum and central nervous system (CNS) compared to wild-type (WT) mice. This was not due to a defect in humoral immunity, as Cd22−/− mice had normal WNV-specific antibody responses. However, Cd22−/− mice had decreased WNV-specific CD8+ T cell responses compared to those of WT mice. These defects were not simply due to reduced cytotoxic activity or increased cell death but, rather, were associated with decreased lymphocyte migration into the draining lymph nodes (dLNs) of infected Cd22−/− mice. Cd22−/− mice had reduced production of the chemokine CCL3 in the dLNs after infection, suggesting that CD22 affects chemotaxis via controlling chemokine production. CD22 was not restricted to B cells but was also expressed on a subset of splenic DCIR2+ dendritic cells that rapidly expand early after WNV infection. Thus, CD22 plays an essential role in controlling WNV infection by governing cell migration and CD8+ T cell responses. PMID:23302871

DSCAM Localization and Function at the Mouse Cone Synapse

PubMed Central

de Andrade, Gabriel Belem; Long, Samuel S.; Fleming, Harrison; Li, Wei; Fuerst, Peter G.

2014-01-01

The Down Syndrome Cell Adhesion Molecule (DSCAM) is required for regulation of cell number, soma spacing and cell type specific dendrite avoidance in many types of retinal ganglion and amacrine cells. In this study we assay the organization of cells making up the outer plexiform layer of the retina in the absence of Dscam. Some types of OFF bipolar cells, type 3b and type 4 bipolar cells, had defects in dendrite arborization in the Dscam mutant retina, while other cell types appeared similar to wild type. The cone synapses that these cells project their dendrites to were intact, as visualized by electron microscopy, and had a distribution and density that was not significantly different than wild type. The spacing of type 3b bipolar cell dendrites was further analyzed by Voronoi domain analysis, Density Recovery Profiling (DRP) analysis and Nearest Neighbor Analysis (NNA). Spacing was found to be significantly different when comparing wild type and mutant type 3b bipolar cell dendrites. Defects in arborization of these bipolar cells could not be attributed to the disorganization of inner plexiform layer cells that occurs in the Dscam mutant retina or an increase in cell number, as they arborized when Dscam was targeted in retinal ganglion cells only or in the bax null retina. Localization of DSCAM was assayed and the protein was localized near to cone synapses in mouse, macaque and ground squirrel retinas. DSCAM protein was detected in several types of bipolar cells, including type 3b and type 4 bipolar cells. PMID:24477985

Effects of Borax on the Reduction of Pre-oxidized Panzhihua Ilmenite

NASA Astrophysics Data System (ADS)

Guo, Yufeng; Zheng, Fuqiang; Jiang, Tao; Chen, Feng; Wang, Shuai; Qiu, Guanzhou

2018-01-01

The effects of borax (sodium borate) on the enhancement reduction of pre-oxidized Panzhihua ilmenite were investigated. The effects of borax on the mineral phase transformation, microstructures, crystal cell parameter, melting point and Mg distribution were studied to reveal the mechanism of enhancement reduction. Under the constant reduction conditions, the borax could reduce the reduction activation energy of pre-oxidized ilmenite. The reduction kinetics analysis indicated that the reduction rate was controlled by interfacial chemical reaction. The reduction activation energy of the pre-oxidized ilmenite with 4% borax was 80.263 kJ/mol, which was 28.585 kJ/mol less than that of the pre-oxidized ilmenite without borax. Borax could eliminate the migration of Mg into the reduced particle center. The crystal cell parameter of the reduced product was increased by adding borax. Borax could improve the growth of dendritic crystals in the pre-oxidized ilmenite.

Measuring Lithium Dendritic Growth in Polymer Electrolytes

NASA Astrophysics Data System (ADS)

He, Yuping; Downing, Gregory; Wang, Howard

The nature of Li dendritic growth in polymeric electrolytes for rechargeable batteries has been investigated using simultaneous electrochemical and neutron depth profiling (NDP) measurements. A symmetric sandwich cell of Li / poly(ethyleneoxide) (PEO) : lithium bis(trifluoromethane)sulfonamide (LiTFSI) / Li was used as a model system in this study. Operating the cell at a constant electric current of 0.1 mA, in situ NDP measurements show that after a period of steady Li plating, dendrites start to grow, which eventually short-circuit the sandwich cell. 3D Li mapping reveals heterogeneous lateral distribution of Li over length scales from below a millimeter to centimeters. Most Li in the electrolyte layer resides in dendrites growing from the top electrode, it is observed that dendrites also grow from the bottom electrode, where presumably only Li oxidation reaction occurs. The revelation poses new design and engineering challenges in using Li metal electrode in future development of rechargeable batteries.

Rotavirus Activates Lymphocytes from Non-Obese Diabetic Mice by Triggering Toll-Like Receptor 7 Signaling and Interferon Production in Plasmacytoid Dendritic Cells

PubMed Central

Pane, Jessica A.; Webster, Nicole L.; Coulson, Barbara S.

2014-01-01

It has been proposed that rotavirus infection promotes the progression of genetically-predisposed children to type 1 diabetes, a chronic autoimmune disease marked by infiltration of activated lymphocytes into pancreatic islets. Non-obese diabetic (NOD) mice provide a model for the human disease. Infection of adult NOD mice with rhesus monkey rotavirus (RRV) accelerates diabetes onset, without evidence of pancreatic infection. Rather, RRV spreads to the pancreatic and mesenteric lymph nodes where its association with antigen-presenting cells, including dendritic cells, induces cellular maturation. RRV infection increases levels of the class I major histocompatibility complex on B cells and proinflammatory cytokine expression by T cells at these sites. In autoimmunity-resistant mice and human mononuclear cells from blood, rotavirus-exposed plasmacytoid dendritic cells contribute to bystander polyclonal B cell activation through type I interferon expression. Here we tested the hypothesis that rotavirus induces bystander activation of lymphocytes from NOD mice by provoking dendritic cell activation and proinflammatory cytokine secretion. NOD mouse splenocytes were stimulated with rotavirus and assessed for activation by flow cytometry. This stimulation activated antigen-presenting cells and B cells independently of virus strain and replicative ability. Instead, activation depended on virus dose and was prevented by blockade of virus decapsidation, inhibition of endosomal acidification and interference with signaling through Toll-like receptor 7 and the type I interferon receptor. Plasmacytoid dendritic cells were more efficiently activated than conventional dendritic cells by RRV, and contributed to the activation of B and T cells, including islet-autoreactive CD8+ T cells. Thus, a double-stranded RNA virus can induce Toll-like receptor 7 signaling, resulting in lymphocyte activation. Our findings suggest that bystander activation mediated by type I interferon contributes to the lymphocyte activation observed following RRV infection of NOD mice, and may play a role in diabetes acceleration by rotavirus. PMID:24676425

pDC therapy induces recovery from EAE by recruiting endogenous pDC to sites of CNS inflammation.

PubMed

Duraes, Fernanda V; Lippens, Carla; Steinbach, Karin; Dubrot, Juan; Brighouse, Dale; Bendriss-Vermare, Nathalie; Issazadeh-Navikas, Shohreh; Merkler, Doron; Hugues, Stephanie

2016-02-01

Plasmacytoid dendritic cells (pDCs) exhibit both innate and adaptive functions. In particular they are the main source of type I IFNs and directly impact T cell responses through antigen presentation. We have previously demonstrated that during experimental autoimmune encephalomyelitis (EAE) initiation, myelin-antigen presentation by pDCs is associated with suppressive Treg development and results in attenuated EAE. Here, we show that pDCs transferred during acute disease phase confer recovery from EAE. Clinical improvement is associated with migration of injected pDCs into inflamed CNS and is dependent on the subsequent and selective chemerin-mediated recruitment of endogenous pDCs to the CNS. The protective effect requires pDC pre-loading with myelin antigen, and is associated with the modulation of CNS-infiltrating pDC phenotype and inhibition of CNS encephalitogenic T cells. This study may pave the way for novel pDC-based cell therapies in autoimmune diseases, aiming at specifically modulating pathogenic cells that induce and sustain autoimmune inflammation. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Selective Susceptibility of Human Skin Antigen Presenting Cells to Productive Dengue Virus Infection

PubMed Central

Cerny, Daniela; Haniffa, Muzlifah; Shin, Amanda; Bigliardi, Paul; Tan, Bien Keem; Lee, Bernett; Poidinger, Michael; Tan, Ern Yu; Ginhoux, Florent; Fink, Katja

2014-01-01

Dengue is a growing global concern with 390 million people infected each year. Dengue virus (DENV) is transmitted by mosquitoes, thus host cells in the skin are the first point of contact with the virus. Human skin contains several populations of antigen-presenting cells which could drive the immune response to DENV in vivo: epidermal Langerhans cells (LCs), three populations of dermal dendritic cells (DCs), and macrophages. Using samples of normal human skin we detected productive infection of CD14+ and CD1c+ DCs, LCs and dermal macrophages, which was independent of DC-SIGN expression. LCs produced the highest viral titers and were less sensitive to IFN-β. Nanostring gene expression data showed significant up-regulation of IFN-β, STAT-1 and CCL5 upon viral exposure in susceptible DC populations. In mice infected intra-dermally with DENV we detected parallel populations of infected DCs originating from the dermis and migrating to the skin-draining lymph nodes. Therefore dermal DCs may simultaneously facilitate systemic spread of DENV and initiate the adaptive anti-viral immune response. PMID:25474532

Monkey extensor digitorum communis motoneuron pool: Proximal dendritic trees and small motoneurons.

PubMed

Jenny, Arthur B; Cheney, Paul D; Jenny, Andrew K

2018-05-14

Transverse sections of the monkey cervical spinal cord from a previous study (Jenny and Inukai, 1983) were reanalyzed using Neurolucida to create a three-dimensional display of extensor digitorum communis (EDC) motoneurons and proximal dendrites that had been labeled with horse radish peroxidase (HRP). The EDC motoneuron pool was located primarily in the C8 and T1 segments of the spinal cord. Small motoneurons (cell body areas less than 500 μm 2 and presumed to be gamma motoneurons) comprised about ten percent of the motoneurons and were located throughout the length of the motoneuron pool. Most small motoneurons were oblong in shape and had one or two major dendrites originating from the cell body in the transverse plane of section. The majority of the HRP labeled dendritic trees were directed either superiorly, dorsal-medially to the mid zone area between the base of the dorsal horn and the upper portion of the ventral horn, or medially to the ventromedial gray matter. The longer HRP labeled dendrites usually continued in the same radial direction as when originating from the cell body. As such we considered the radial direction of the longer proximal HRP labeled dendrites to be a reasonable estimate of the radial direction of the more distal dendritic tree. Our data suggest that the motoneuron dendritic tree as seen in transverse section has direction-oriented dendrites that extend toward functional terminal regions. Copyright © 2018 Elsevier B.V. All rights reserved.

Frequent Calcium Oscillations Lead to NFAT Activation in Human Immature Dendritic Cells*

PubMed Central

Vukcevic, Mirko; Zorzato, Francesco; Spagnoli, Giulio; Treves, Susan

2010-01-01

Spontaneous Ca2+ oscillations have been observed in a number of excitable and non-excitable cells, but in most cases their biological role remains elusive. In the present study we demonstrate that spontaneous Ca2+ oscillations occur in immature human monocyte-derived dendritic cells but not in dendritic cells stimulated to undergo maturation with lipopolysaccharide or other toll like-receptor agonists. We investigated the mechanism and role of spontaneous Ca2+ oscillations in immature dendritic cells and found that they are mediated by the inositol 1,4,5-trisphosphate receptor as they were blocked by pretreatment of cells with the inositol 1,4,5-trisphosphate receptor antagonist Xestospongin C and 2-aminoethoxydiphenylborate. A component of the Ca2+ signal is also due to influx from the extracellular environment and may be involved in maintaining the level of the intracellular Ca2+ stores. As to their biological role, our results indicate that they are intimately linked to the “immature” phenotype and are associated with the translocation of the transcription factor NFAT into the nucleus. In fact, once the Ca2+ oscillations are blocked with 2-aminoethoxydiphenylborate or by treating the cells with lipopolysaccharide, NFAT remains cytoplasmic. The results presented in this report provide novel insights into the physiology of monocyte-derived dendritic cells and into the mechanisms involved in maintaining the cells in the immature stage. PMID:20348098

ISOLATION OF CHICKEN FOLLICULAR DENDRITIC CELLS

USDA-ARS?s Scientific Manuscript database

The aim of the present study was to isolate chicken follicular dendritic cells (FDC). A combination of methods involving panning, iodixanol density gradient centrifugation, and magnetic cell separation technology made it possible to obtain functional FDC from the cecal tonsils from chickens, which h...

Type I interferon regulates pDC maturation and Ly49Q expression.

PubMed

Toma-Hirano, Makiko; Namiki, Sahori; Miyatake, Shoichiro; Arai, Ken-Ichi; Kamogawa-Schifter, Yumiko

2007-10-01

Ly49Q is expressed on peripheral mouse plasmacytoid dendritic cells (pDC). Immature Ly49Q-negative pDC precursors acquire Ly49Q in the bone marrow and then migrate into the periphery. While searching for molecules that regulate pDC maturation, we found that type I interferon (IFN) inhibited Ly49Q acquisition in vitro. Infections that induce type I IFN production by cells other than pDC (a condition mimicked by poly(I:C) injection in vivo) increase the prevalence of Ly49Q(-) pDC in the bone marrow and peripheral lymphoid organs in wild-type but not IFN-alpha/beta receptor knockout BALB/c mice. Moreover, in vivo exposure to type I IFN causes some Ly49Q(-), but not Ly49Q(+), pDC to convert to conventional DC, defined as B220(-) CD11c(+) CD11b(+) cells. These data suggest that type I IFN regulates pDC development and affects their distribution in the body.

Enriched Environment Increases PCNA and PARP1 Levels in Octopus vulgaris Central Nervous System: First Evidence of Adult Neurogenesis in Lophotrochozoa.

PubMed

Bertapelle, Carla; Polese, Gianluca; Di Cosmo, Anna

2017-06-01

Organisms showing a complex and centralized nervous system, such as teleosts, amphibians, reptiles, birds and mammals, and among invertebrates, crustaceans and insects, can adjust their behavior according to the environmental challenges. Proliferation, differentiation, migration, and axonal and dendritic development of newborn neurons take place in brain areas where structural plasticity, involved in learning, memory, and sensory stimuli integration, occurs. Octopus vulgaris has a complex and centralized nervous system, located between the eyes, with a hierarchical organization. It is considered the most "intelligent" invertebrate for its advanced cognitive capabilities, as learning and memory, and its sophisticated behaviors. The experimental data obtained by immunohistochemistry and western blot assay using proliferating cell nuclear antigen and poli (ADP-ribose) polymerase 1 as marker of cell proliferation and synaptogenesis, respectively, reviled cell proliferation in areas of brain involved in learning, memory, and sensory stimuli integration. Furthermore, we showed how enriched environmental conditions affect adult neurogenesis. © 2017 Wiley Periodicals, Inc.

Preclinical evaluation of mRNA trimannosylated lipopolyplexes as therapeutic cancer vaccines targeting dendritic cells.

PubMed

Le Moignic, A; Malard, V; Benvegnu, T; Lemiègre, L; Berchel, M; Jaffrès, P-A; Baillou, C; Delost, M; Macedo, R; Rochefort, J; Lescaille, G; Pichon, C; Lemoine, F M; Midoux, P; Mateo, V

2018-05-28

Clinical trials with direct administration of synthetic mRNAs encoding tumor antigens demonstrated safety and induction of tumor-specific immune responses. Their proper delivery to dendritic cells (DCs) requires their protection against RNase degradation and more specificity for dose reduction. Lipid-Polymer-RNA lipopolyplexes (LPR) are attractive mRNA delivery systems and their equipment with mannose containing glycolipid, specific of endocytic receptors present on the membrane of DCs is a valuable strategy. In this present work, we evaluated the capacity of LPR functionalized with a tri-antenna of α-d-mannopyranoside (triMN-LPR) concerning (i) their binding to CD209/DC-SIGN and CD207/Langerin expressing cell lines, human and mouse DCs and other hematopoietic cell populations, (ii) the nature of induced immune response after in vivo immunization and (iii) their therapeutic anti-cancer vaccine efficiency. We demonstrated that triMN-LPR provided high induction of a local inflammatory response two days after intradermal injection to C57BL/6 mice, followed by the recruitment and activation of DCs in the corresponding draining lymph nodes. This was associated with skin production of CCR7 and CXCR4 at vaccination sites driving DC migration. High number of E7-specific T cells was detected after E7-encoded mRNA triMN-LPR vaccination. When evaluated in three therapeutic pre-clinical murine tumor models such as E7-expressing TC1 cells, OVA-expressing EG7 cells and MART-1-expressing B16F0 cells, triMN-LPR carrying mRNA encoding the respective antigens significantly exert curative responses in mice vaccinated seven days after initial tumor inoculation. These results provide evidence that triMN-LPR give rise to an efficient stimulatory immune response allowing for therapeutic anti-cancer vaccination in mice. This mRNA formulation should be considered for anti-cancer vaccination in Humans. Copyright © 2018 Elsevier B.V. All rights reserved.

Preparation of Horizontal Slices of Adult Mouse Retina for Electrophysiological Studies.

PubMed

Feigenspan, Andreas; Babai, Norbert Zsolt

2017-01-27

Vertical slice preparations are well established to study circuitry and signal transmission in the adult mammalian retina. The plane of sectioning in these preparations is perpendicular to the retinal surface, making it ideal for the study of radially oriented neurons like photoreceptors and bipolar cells. However, the large dendritic arbors of horizontal cells, wide-field amacrine cells, and ganglion cells are mostly truncated, leaving markedly reduced synaptic activity in these cells. Whereas ganglion cells and displaced amacrine cells can be studied in a whole-mounted preparation of the retina, horizontal cells and amacrine cells located in the inner nuclear layer are only poorly accessible for electrodes in whole retina tissue. To achieve maximum accessibility and synaptic integrity, we developed a horizontal slice preparation of the mouse retina, and studied signal transmission at the synapse between photoreceptors and horizontal cells. Horizontal sectioning allows (1) easy and unambiguous visual identification of horizontal cell bodies for electrode targeting, and (2) preservation of the extended horizontal cell dendritic fields, as a prerequisite for intact and functional cone synaptic input to horizontal cell dendrites. Horizontal cells from horizontal slices exhibited tonic synaptic activity in the dark, and they responded to brief flashes of light with a reduction of inward current and diminished synaptic activity. Immunocytochemical evidence indicates that almost all cones within the dendritic field of a horizontal cell establish synapses with its peripheral dendrites. The horizontal slice preparation is therefore well suited to study the physiological properties of horizontally extended retinal neurons as well as sensory signal transmission and integration across selected synapses.

Dendritic Properties Control Energy Efficiency of Action Potentials in Cortical Pyramidal Cells

PubMed Central

Yi, Guosheng; Wang, Jiang; Wei, Xile; Deng, Bin

2017-01-01

Neural computation is performed by transforming input signals into sequences of action potentials (APs), which is metabolically expensive and limited by the energy available to the brain. The metabolic efficiency of single AP has important consequences for the computational power of the cell, which is determined by its biophysical properties and morphologies. Here we adopt biophysically-based two-compartment models to investigate how dendrites affect energy efficiency of APs in cortical pyramidal neurons. We measure the Na+ entry during the spike and examine how it is efficiently used for generating AP depolarization. We show that increasing the proportion of dendritic area or coupling conductance between two chambers decreases Na+ entry efficiency of somatic AP. Activating inward Ca2+ current in dendrites results in dendritic spike, which increases AP efficiency. Activating Ca2+-activated outward K+ current in dendrites, however, decreases Na+ entry efficiency. We demonstrate that the active and passive dendrites take effects by altering the overlap between Na+ influx and internal current flowing from soma to dendrite. We explain a fundamental link between dendritic properties and AP efficiency, which is essential to interpret how neural computation consumes metabolic energy and how biophysics and morphologies contribute to such consumption. PMID:28919852

Dendritic Properties Control Energy Efficiency of Action Potentials in Cortical Pyramidal Cells.

PubMed

Yi, Guosheng; Wang, Jiang; Wei, Xile; Deng, Bin

2017-01-01

Neural computation is performed by transforming input signals into sequences of action potentials (APs), which is metabolically expensive and limited by the energy available to the brain. The metabolic efficiency of single AP has important consequences for the computational power of the cell, which is determined by its biophysical properties and morphologies. Here we adopt biophysically-based two-compartment models to investigate how dendrites affect energy efficiency of APs in cortical pyramidal neurons. We measure the Na + entry during the spike and examine how it is efficiently used for generating AP depolarization. We show that increasing the proportion of dendritic area or coupling conductance between two chambers decreases Na + entry efficiency of somatic AP. Activating inward Ca 2+ current in dendrites results in dendritic spike, which increases AP efficiency. Activating Ca 2+ -activated outward K + current in dendrites, however, decreases Na + entry efficiency. We demonstrate that the active and passive dendrites take effects by altering the overlap between Na + influx and internal current flowing from soma to dendrite. We explain a fundamental link between dendritic properties and AP efficiency, which is essential to interpret how neural computation consumes metabolic energy and how biophysics and morphologies contribute to such consumption.

Identification, characterization and isolation of a common progenitor for osteoclasts, macrophages and dendritic cells from murine bone marrow and periphery

PubMed Central

Jacome-Galarza, Christian E.; Lee, Sun-Kyeong; Lorenzo, Joseph A.; LeonardoAguila, Hector

2012-01-01

Osteoclasts are specialized bone resorbing cells that derive from monocyte precursors. We have identified three populations of cells with high osteoclastogenic potential in murine bone marrow, which expressed the phenotype: B220−CD3−CD11b−/low CD115+ and either CD117hi, CD117intermediate or CD117low. We have evaluated these populations for their ability to also generate macrophages and dendritic cells. At a single cell level, the population expressing higher CD117 levels was able to generate bone-resorbing osteoclasts, phagocytic macrophages and antigen-presenting dendritic cells in vitro with efficiencies of over 90 percent, indicating that there exists a common developmental pathway for these cell types. Cells with osteoclastogenic potential also exist in blood and peripheral hematopoietic organs. Their functional meaning and/or their relationship with bone marrow progenitors is not well established. Hence, we characterized murine peripheral cell populations for their ability to form osteoclasts, macrophages and dendritic cells in vitro. The spleen and peripheral blood monocyte progenitors share phenotypic markers with bone marrow progenitors, but differ in their expression of CD11b, which was low in bone marrow but high in periphery. We propose that circulating monocyte progenitors are derived from a common bone marrow osteoclasts/macrophage/dendritic cell progenitor (OcMDC), which we have now characterized at a clonal level. However, the lineage relationship between the bone marrow and peripheral monocyte progenitors has yet to be defined. PMID:23165930

The Interactive Roles of Lipopolysaccharides and dsRNA/Viruses on Respiratory Epithelial Cells and Dendritic Cells in Allergic Respiratory Disorders: The Hygiene Hypothesis.

PubMed

Lin, Tsang-Hsiung; Su, Hsing-Hao; Kang, Hong-Yo; Chang, Tsung-Hsien

2017-10-23

The original hygiene hypothesis declares "more infections in early childhood protect against later atopy". According to the hygiene hypothesis, the increased incidence of allergic disorders in developed countries is explained by the decrease of infections. Epithelial cells and dendritic cells play key roles in bridging the innate and adaptive immune systems. Among the various pattern-recognition receptor systems of epithelial cells and dendritic cells, including toll-like receptors (TLRs), nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) and others, TLRs are the key systems of immune response regulation. In humans, TLRs consist of TLR1 to TLR10. They regulate cellular responses through engagement with TLR ligands, e.g., lipopolysaccharides (LPS) acts through TLR4 and dsRNA acts through TLR3, but there are certain common components between these two TLR pathways. dsRNA activates epithelial cells and dendritic cells in different directions, resulting in allergy-related Th2-skewing tendency in epithelial cells, and Th1-skewing tendency in dendritic cells. The Th2-skewing effect by stimulation of dsRNA on epithelial cells could be suppressed by the presence of LPS above some threshold. When LPS level decreases, the Th2-skewing effect increases. It may be via these interrelated networks and related factors that LPS modifies the allergic responses and provides a plausible mechanism of the hygiene hypothesis. Several hygiene hypothesis-related phenomena, seemingly conflicting, are also discussed in this review, along with their proposed mechanisms.

Adenosine Deaminase Enhances the Immunogenicity of Human Dendritic Cells from Healthy and HIV-Infected Individuals

PubMed Central

Massanella, Marta; Rodríguez-García, Marta; Blanco, Julià; Gatell, José M.; García, Felipe; Gallart, Teresa; Lluis, Carme; Mallol, Josefa

2012-01-01

ADA is an enzyme implicated in purine metabolism, and is critical to ensure normal immune function. Its congenital deficit leads to severe combined immunodeficiency (SCID). ADA binding to adenosine receptors on dendritic cell surface enables T-cell costimulation through CD26 crosslinking, which enhances T-cell activation and proliferation. Despite a large body of work on the actions of the ecto-enzyme ADA on T-cell activation, questions arise on whether ADA can also modulate dendritic cell maturation. To this end we investigated the effects of ADA on human monocyte derived dendritic cell biology. Our results show that both the enzymatic and non-enzymatic activities of ADA are implicated in the enhancement of CD80, CD83, CD86, CD40 and CCR7 expression on immature dendritic cells from healthy and HIV-infected individuals. These ADA-mediated increases in CD83 and costimulatory molecule expression is concomitant to an enhanced IL-12, IL-6, TNF-α, CXCL8(IL-8), CCL3(MIP1-α), CCL4(MIP-1β) and CCL5(RANTES) cytokine/chemokine secretion both in healthy and HIV-infected individuals and to an altered apoptotic death in cells from HIV-infected individuals. Consistently, ADA-mediated actions on iDCs are able to enhance allogeneic CD4 and CD8-T-cell proliferation, globally yielding increased iDC immunogenicity. Taken together, these findings suggest that ADA would promote enhanced and correctly polarized T-cell responses in strategies targeting asymptomatic HIV-infected individuals. PMID:23240012

Decreased metastatic phenotype in cells resistant to Aminolevulinic acid-Photodynamic therapy

PubMed Central

Casas, Adriana; Di Venosa, Gabriela; Vanzulli, Silvia; Perotti, Christian; Mamome, Leandro; Rodriguez, Lorena; Simian, Marina; Juarranz, Angeles; Pontiggia, Osvaldo; Hasan, Tayyaba; Batlle, Alcira

2008-01-01

Photodynamic therapy (PDT) is a novel cancer treatment utilising a photosensitiser, visible light and oxygen. PDT often leaves a significant number of surviving tumour cells. In a previous work, we isolated and studied two PDT resistant clones derived from the mammary adenocarcinoma LM3 line (Int. J. Oncol. 29 (2006) 397–405). The isolated Clon 4 and Clon 8 exhibited a more fibroblastic, dendritic pattern and were larger than the parentals. In the present work we studied the metastatic potential of the two clones in comparison with LM3. We found that 100 % of LM3 invaded Matrigel, whereas only 19 ± 6 % and 24 ± 7 % of Clon 4 and Clon 8 cells invaded. In addition, 100% of LM3 cells migrated towards a chemotactic stimulus whereas 38 ± 8 % and 73 ± 10 % of Clones 4 and 8 respectively were able to migrate. In vivo, 100% of the LM3 injected mice developed spontaneous lung metastasis, whereas none of the Clon 8 did, and only one of the mice injected with Clon 4 did. No differences were found in the proteolytic enzyme profiles among the cells. Anchorage-dependent adhesion was also impaired in vivo in the resistant clones, evidenced by the lower tumour take, latency time and growth rates, although both clones showed in vitro higher binding to collagen I without overexpression of β1 integrin. This is the first work where the metastatic potential of cells surviving to PDT has been studied. PDT strongly affects the invasive phenotype of these cells, probably related to a higher binding to collagen. These findings may be crucial for the outcome of ALA-PDT of metastatic tumours, although further studies are needed to extrapolate the results to the clinic employing another photosensitisers and cell types. PMID:18662847

Olfactory granule cell development in normal and hyperthyroid rats.

PubMed

Brunjes, P C; Schwark, H D; Greenough, W T

1982-10-01

Dendritic development was examined in olfactory bulbs of both normal 7-, 14-, 21- and 60-day-old rats and littermates treated on postnatal days 1-4 with 1 microgram/g body weight of L-thyroxine sodium. Tissue was processed via the Golgi-Cox technique and subjected to quantitative analyses of mitral and internal layer granule cell development. These populations of granule cells were selected because their pattern of late proliferation suggested potentially greater susceptibility to postnatal hormonal alterations. Although neonatal hyperthyroidism induces widespread acceleration of maturation, including precocious chemosensitivity, granule cell development was unaffected relative to littermate controls. Both normal and hyperthyroid groups exhibited an inverted U-shaped pattern of cellular development, with rapid dendritic dendritic growth and expansion occurring during the earliest ages tested, but with loss of processes and dendritic field size occurring after day 21.

Vaccination with dendritic cells pulsed with hepatitis C pseudo particles induces specific immune responses in mice

PubMed Central

Weigand, Kilian; Voigt, Franziska; Encke, Jens; Hoyler, Birgit; Stremmel, Wolfgang; Eisenbach, Christoph

2012-01-01

AIM: To explore dendritic cells (DCs) multiple functions in immune modulation. METHODS: We used bone-marrow derived dendritic cells from BALB/c mice pulsed with pseudo particles from the hepatitis C virus to vaccinate naive BALB/c mice. Hepatitis C virus (HCV) pseudo particles consist of the genotype 1b derived envelope proteins E1 and E2, covering a non-HCV core structure. Thus, not a single epitope, but the whole “viral surface” induces immunogenicity. For vaccination, mature and activated DC were injected subcutaneously twice. RESULTS: Humoral and cellular immune responses measured by enzyme-linked immunosorbent assay and interferon-gamma enzyme-linked immunosorbent spot test showed antibody production as well as T-cells directed against HCV. Furthermore, T-cell responses confirmed two highly immunogenic regions in E1 and E2 outside the hypervariable region 1. CONCLUSION: Our results indicate dendritic cells as a promising vaccination model for HCV infection that should be evaluated further. PMID:22371638

Comparative analysis of signature genes in porcine reproductive and respiratory syndrome virus (PRRSV)-infected porcine monocyte-derived dendritic cells at differential activation statuses

USDA-ARS?s Scientific Manuscript database

Activation statuses of monocytic cells, e.g. monocytes, macrophages and dendritic cells (DCs), are critically important for antiviral immunity. In particular, some devastating viruses, including porcine reproductive and respiratory syndrome virus (PRRSV), are capable of directly infecting these cell...

A bloody mess: dendritic cells use hemophagocytosis to regulate viral inflammation.

PubMed

Miller, Elizabeth; Bhardwaj, Nina

2013-09-19

Previous studies have highlighted the immune-dampening effects of apoptotic cell uptake by phagocytes. Ohyagi et al. (2013) expose a unique mechanism of immune regulation during viral infection, which is mediated through phagocytosis of apoptotic red cells by dendritic cells. Copyright © 2013 Elsevier Inc. All rights reserved.

Cell Type–Specific Three-Dimensional Structure of Thalamocortical Circuits in a Column of Rat Vibrissal Cortex

PubMed Central

de Kock, Christiaan P. J.; Bruno, Randy M.; Ramirez, Alejandro; Meyer, Hanno S.; Dercksen, Vincent J.; Helmstaedter, Moritz; Sakmann, Bert

2012-01-01

Soma location, dendrite morphology, and synaptic innervation may represent key determinants of functional responses of individual neurons, such as sensory-evoked spiking. Here, we reconstruct the 3D circuits formed by thalamocortical afferents from the lemniscal pathway and excitatory neurons of an anatomically defined cortical column in rat vibrissal cortex. We objectively classify 9 cortical cell types and estimate the number and distribution of their somata, dendrites, and thalamocortical synapses. Somata and dendrites of most cell types intermingle, while thalamocortical connectivity depends strongly upon the cell type and the 3D soma location of the postsynaptic neuron. Correlating dendrite morphology and thalamocortical connectivity to functional responses revealed that the lemniscal afferents can account for some of the cell type- and location-specific subthreshold and spiking responses after passive whisker touch (e.g., in layer 4, but not for other cell types, e.g., in layer 5). Our data provides a quantitative 3D prediction of the cell type–specific lemniscal synaptic wiring diagram and elucidates structure–function relationships of this physiologically relevant pathway at single-cell resolution. PMID:22089425

Role of hepatocyte growth factor in the development of dendritic cells from CD34+ bone marrow cells.

PubMed

Ovali, E; Ratip, S; Kibaroglu, A; Tekelioglu, Y; Cetiner, M; Karti, S; Aydin, F; Bayik, M; Akoglu, T

2000-05-01

Hepatocyte growth factor (HGF) is known to augment the effects of stem cell factor, interleukin-3, granulocyte-macrophage colony-stimulating factor (GM-CSF), erythropoetin, and granulocyte colony-stimulating factor, all of which are involved in hematopoiesis. HGF is also known to have a role in immune responses. The aim of this study was to investigate whether HGF is involved in the development of dendritic cells (DC) from CD34+ bone marrow cells. CD34+ cells obtained from three healthy donors were incubated in various combinations of HGF, GM-CSF, and tumor necrosis factor (TNF) for 12 days. Developing cell populations were analyzed for surface markers, morphology and functional capacities by flow cytometry, light microscopy and mixed lymphocyte reaction, respectively. Incubation with HGF alone generated greater number of dendritic cells from CD34+ bone marrow cells than incubation with GM-CSF, or a combination of GM-CSF with TNF. HGF was also found to potentiate the effect of GM-CSF on DC and monocyte development. The effects of HGF were inhibited by the concurrent use of TNF. HGF appears to be a significant factor in the development of dendritic cells from CD34+ bone marrow cells.

Thymic Dendritic Cells Are Primary Targets for the Oncogenic Virus SL3-3

PubMed Central

Uittenbogaart, Christel H.; Law, Wendy; Leenen, Pieter J. M.; Bristol, Gregory; van Ewijk, Willem; Hays, Esther F.

1998-01-01

The murine retrovirus SL3-3 causes malignant transformation of thymocytes and thymic lymphoma in mice of the AKR and NFS strains when they are inoculated neonatally. The objective of the present study was to identify the primary target cells for the virus in the thymuses of these mice. Immunohistochemical studies of the thymus after neonatal inoculation of the SL3-3 virus showed that cells expressing the viral envelope glycoprotein (gp70+ cells) were first seen at 2 weeks of age. These virus-expressing cells were found in the cortex and at the corticomedullary junction in both mouse strains. The gp70+ cells had the morphology and immunophenotype of dendritic cells. They lacked macrophage-specific antigens. Cell separation studies showed that bright gp70+ cells were detected in a fraction enriched for dendritic cells. At 3 weeks of age, macrophages also expressed gp70. At that time, both gp70+ dendritic cells and macrophages were found at the corticomedullary junction and in foci in the thymic cortex. At no time during this 3-week period was the virus expressed in cortical and medullary epithelial cells or in thymic lymphoid cells. Infectious cell center assays indicated that cells expressing infectious virus were present in small numbers at 2 weeks after inoculation but increased at 5 weeks of age by several orders of magnitude, indicating virus spread to the thymic lymphoid cells. Thus, at 2 weeks after neonatal inoculation of SL3-3, thymic dendritic cells are the first cells to express the virus. At 3 weeks of age, macrophages also express the virus. In subsequent weeks, the virus spreads to the thymocytes. This pathway of virus expression in the thymus allows the inevitable provirus integration in a thymocyte that results in a clonal lymphoma. PMID:9811752

Identification and molecular profiling of DC-SIGN-like from big belly seahorse (Hippocampus abdominalis) inferring its potential relevancy in host immunity.

PubMed

Jo, Eunyoung; Elvitigala, Don Anushka Sandaruwan; Wan, Qiang; Oh, Minyoung; Oh, Chulhong; Lee, Jehee

2017-12-01

Dendritic-cell-specific ICAM-3-grabbing non-integrin (DC-SIGN) is a C-type lectin that functions as a pattern recognition receptor by recognizing pathogen-associated molecular patterns (PAMPs). It is also involved in various events of the dendritic cell (DC) life cycle, such as DC migration, antigen capture and presentation, and T cell priming. In this study, a DC-SIGN-like gene from the big belly seahorse Hippocampus abdominalis (designated as ShDCS-like) was identified and molecularly characterized. The putative, complete ORF was found to be 1368 bp in length, encoding a protein of 462 amino acids with a molecular mass of 52.6 kDa and a theoretical isoelectric point of 8.26. The deduced amino acid sequence contains a single carbohydrate recognition domain (CRD), in which six conserved cysteine residues and two Ca 2+ -binding site motifs (QPN, WND) were identified. Based on pairwise sequence analysis, ShDCS-like exhibits the highest amino acid identity (94.6%) and similarity (97.4%) with DC-SIGN-like counterpart from tiger tail seahorse Hippocampus comes. Quantitative real-time PCR revealed that ShDCS-like mRNA is transcribed universally in all tissues examined, but with abundance in kidney and gill tissues. The basal mRNA expression of ShDCS-like was modulated in blood cell, kidney, gill and liver tissues in response to the stimulation of healthy fish with lipopolysaccharides (LPS), Edwardsiella tarda, or Streptococcus iniae. Moreover, recombinant ShDCS-like-CRD domain exhibited detectable agglutination activity against different bacteria. Collectively, these results suggest that ShDCS-like may potentially involve in immune function in big belly seahorses. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cutaneous myeloid dendritic cell dyscrasia: A cutaneous clonal monocytosis associated with chronic myeloproliferative disorders and peripheral blood monocytosis.

PubMed

Magro, Cynthia M; Momtahen, Shabnam; Verma, Shalini; Abraham, Ronnie M; Friedman, Constantin; Nuovo, Gerard J; Tam, Wayne

2016-12-01

Monocytes are critical components of the innate immune system and they can differentiate into dendritic cells (DCs). Cutaneous neoplasms of dendritic cell origin are uncommon and mostly represented by histiocytic lesions derived primarily from Langerhans cells. The myeloid DC (mDC) while recognized in the immunology literature does not have a well-defined neoplastic cutaneous counterpart. Eleven patients with a diagnosis of cutaneous mDC dyscrasia were evaluated. Routine hematoxylin and eosin stain were performed followed by selective phenotypic studies. The patients were older without a gender predilection and exhibited an asymptomatic papular skin rash with a waxing and waning course. The biopsies demonstrated a dermal based monomorphic small mononuclear cell infiltrate. The cells expressed CD14, CD11c, HLA-DR, as well as granzyme and lysozyme that defines terminally differentiated monocyte/dendritic cells. Expression of BDCA-3 (CD141) by the tumor cells indicated that they were myeloid dendritic cells (mDC2). Each patient had a prior or subsequent diagnosis of an abnormal bone marrow biopsy that included myelodysplastic syndrome, myelofibrosis, chronic myelomonocytic leukemia, and acute myelogenous leukemia. We propose the term cutaneous mDC cell dyscrasia for distinctive infiltrates of differentiated mDCs reflective of underlying myeloproliferative disease. The clinical course is variable and can be indolent although it is strongly correlated with myelodysplastic syndrome that included leukemia. Copyright © 2016 Elsevier Inc. All rights reserved.

Identification of dendritic cells in the blood and synovial fluid of children with Juvenile Idiopathic Arthritis.

PubMed

Tabarkiewicz, Jacek; Postępski, Jacek; Olesińska, Edyta; Roliński, Jacek; Tuszkiewicz-Misztal, Ewa

2011-01-01

Childhood chronic arthritis of unknown etiology is known collectively as juvenile idiopathic arthritis (JIA) and consists of heterogeneous subtypes with unique clinical patterns of disease. JIA is the commonest rheumatic disease in children and may still result in significant disability, with joint deformity, growth impairment, and persistence of active arthritis into adulthood. Basic research is rather focused on rheumatoid arthritis, and this lead to small number of publications considering JIA. In this study we examine, by flow cytometry, the expression of dendritic cells (DCs) in the peripheral blood and synovial fluid of children with active JIA in a group of 220 patients. We reveal a significant decrease in the percentage of immature DCs in the blood of patients compared to control children. Surprisingly, we found higher percentages of mature circulating dendritic cells. Both populations of DCs, immature and mature, were accumulated in patients' synovial fluid. We also confirmed the presence of CD206+/CD209+ in JIA samples, which can represent a population of macrophages with dendritic cells morphology. Our results support the thesis that dendritic cells are crucial in the induction and maintenance of autoimmune response and local inflammation during juvenile idiopathic arthritis.

Technical Advance: Live-imaging analysis of human dendritic cell migrating behavior under the influence of immune-stimulating reagents in an organotypic model of lung

PubMed Central

Nguyen Hoang, Anh Thu; Chen, Puran; Björnfot, Sofia; Högstrand, Kari; Lock, John G.; Grandien, Alf; Coles, Mark; Svensson, Mattias

2014-01-01

This manuscript describes technical advances allowing manipulation and quantitative analyses of human DC migratory behavior in lung epithelial tissue. DCs are hematopoietic cells essential for the maintenance of tissue homeostasis and the induction of tissue-specific immune responses. Important functions include cytokine production and migration in response to infection for the induction of proper immune responses. To design appropriate strategies to exploit human DC functional properties in lung tissue for the purpose of clinical evaluation, e.g., candidate vaccination and immunotherapy strategies, we have developed a live-imaging assay based on our previously described organotypic model of the human lung. This assay allows provocations and subsequent quantitative investigations of DC functional properties under conditions mimicking morphological and functional features of the in vivo parental tissue. We present protocols to set up and prepare tissue models for 4D (x, y, z, time) fluorescence-imaging analysis that allow spatial and temporal studies of human DCs in live epithelial tissue, followed by flow cytometry analysis of DCs retrieved from digested tissue models. This model system can be useful for elucidating incompletely defined pathways controlling DC functional responses to infection and inflammation in lung epithelial tissue, as well as the efficacy of locally administered candidate interventions. PMID:24899587

Regeneration of Drosophila sensory neuron axons and dendrites is regulated by the Akt pathway involving Pten and microRNA bantam

PubMed Central

Song, Yuanquan; Ori-McKenney, Kassandra M.; Zheng, Yi; Han, Chun; Jan, Lily Yeh; Jan, Yuh Nung

2012-01-01

Both cell-intrinsic and extrinsic pathways govern axon regeneration, but only a limited number of factors have been identified and it is not clear to what extent axon regeneration is evolutionarily conserved. Whether dendrites also regenerate is unknown. Here we report that, like the axons of mammalian sensory neurons, the axons of certain Drosophila dendritic arborization (da) neurons are capable of substantial regeneration in the periphery but not in the CNS, and activating the Akt pathway enhances axon regeneration in the CNS. Moreover, those da neurons capable of axon regeneration also display dendrite regeneration, which is cell type-specific, developmentally regulated, and associated with microtubule polarity reversal. Dendrite regeneration is restrained via inhibition of the Akt pathway in da neurons by the epithelial cell-derived microRNA bantam but is facilitated by cell-autonomous activation of the Akt pathway. Our study begins to reveal mechanisms for dendrite regeneration, which depends on both extrinsic and intrinsic factors, including the PTEN–Akt pathway that is also important for axon regeneration. We thus established an important new model system—the fly da neuron regeneration model that resembles the mammalian injury model—with which to study and gain novel insights into the regeneration machinery. PMID:22759636

Dendritic nonlinearities are tuned for efficient spike-based computations in cortical circuits.

PubMed

Ujfalussy, Balázs B; Makara, Judit K; Branco, Tiago; Lengyel, Máté

2015-12-24

Cortical neurons integrate thousands of synaptic inputs in their dendrites in highly nonlinear ways. It is unknown how these dendritic nonlinearities in individual cells contribute to computations at the level of neural circuits. Here, we show that dendritic nonlinearities are critical for the efficient integration of synaptic inputs in circuits performing analog computations with spiking neurons. We developed a theory that formalizes how a neuron's dendritic nonlinearity that is optimal for integrating synaptic inputs depends on the statistics of its presynaptic activity patterns. Based on their in vivo preynaptic population statistics (firing rates, membrane potential fluctuations, and correlations due to ensemble dynamics), our theory accurately predicted the responses of two different types of cortical pyramidal cells to patterned stimulation by two-photon glutamate uncaging. These results reveal a new computational principle underlying dendritic integration in cortical neurons by suggesting a functional link between cellular and systems--level properties of cortical circuits.

Proton receptor GPR68 expression in dendritic-cell-like S100β-positive cells of rat anterior pituitary gland: GPR68 induces interleukin-6 gene expression in extracellular acidification.

PubMed

Horiguchi, Kotaro; Higuchi, Masashi; Yoshida, Saishu; Nakakura, Takashi; Tateno, Kozue; Hasegawa, Rumi; Takigami, Shu; Ohsako, Shunji; Kato, Takako; Kato, Yukio

2014-11-01

S100β-positive cells, which do not express the classical pituitary hormones, appear to possess multifunctional properties and are assumed to be heterogeneous in the anterior pituitary gland. The presence of several protein markers has shown that S100β-positive cells are composed of populations such as stem/progenitor cells, epithelial cells, astrocytes and dendritic cells. Recently, we succeeded in separating S100β-positive cells into round-cell (dendritic-cell-like) and process-cell types. We also found the characteristic expression of anti-inflammatory factors (interleukin-6, Il-6) and membrane receptors (integrin β-6) in the round type. Here, we further investigate the function of the subpopulation of S100β-positive cells. Since IL-6 is also a paracrine factor that regulates hormone producing-cells, we examine whether a correlation exists among extracellular acid stress, IL-6 and hormone production by using primary cultures of anterior pituitary cells. Dendritic-cell-like S100β-positive cells notably expressed Gpr68 (proton receptor) and Il-6. Furthermore, the expression of Il-6 and proopiomelanocortin (Pomc) was up-regulated by extracellular acidification. The functional role of IL-6 and GPR68 in the gene expression of Pomc during extracellular acidification was also examined. Small interfering RNA for Il-6 up-regulated Pomc expression and that for Gpr68 reversed the down-regulation of Il-6 and up-regulated Pomc expression by extracellular acidification. Thus, S100β-positive dendritic-like cells can sense an increase in extracellular protons via GPR68 and respond by the production of IL-6 in order to suppress the up-regulation of Pomc expression.

Comparative analysis of signature genes in PRRSV-infected porcine monocyte-derived dendritic cells at differential activation statuses

USDA-ARS?s Scientific Manuscript database

Activation statuses of monocytic cells including monocytes, macrophages and dendritic cells (DCs) are critically important for antiviral immunity. In particular, some devastating viruses, including porcine reproductive and respiratory syndrome virus (PRRSV), are capable of directly infecting these c...

Dynamics of action potential backpropagation in basal dendrites of prefrontal cortical pyramidal neurons.

PubMed

Zhou, Wen-Liang; Yan, Ping; Wuskell, Joseph P; Loew, Leslie M; Antic, Srdjan D

2008-02-01

Basal dendrites of neocortical pyramidal neurons are relatively short and directly attached to the cell body. This allows electrical signals arising in basal dendrites to strongly influence the neuronal output. Likewise, somatic action potentials (APs) should readily propagate back into the basilar dendritic tree to influence synaptic plasticity. Two recent studies, however, determined that sodium APs are severely attenuated in basal dendrites of cortical pyramidal cells, so that they completely fail in distal dendritic segments. Here we used the latest improvements in the voltage-sensitive dye imaging technique (Zhou et al., 2007) to study AP backpropagation in basal dendrites of layer 5 pyramidal neurons of the rat prefrontal cortex. With a signal-to-noise ratio of > 15 and minimal temporal averaging (only four sweeps) we were able to sample AP waveforms from the very last segments of individual dendritic branches (dendritic tips). We found that in short- (< 150 microm) and medium (150-200 microm in length)-range basal dendrites APs backpropagated with modest changes in AP half-width or AP rise-time. The lack of substantial changes in AP shape and dynamics of rise is inconsistent with the AP-failure model. The lack of substantial amplitude boosting of the third AP in the high-frequency burst also suggests that in short- and medium-range basal dendrites backpropagating APs were not severely attenuated. Our results show that the AP-failure concept does not apply in all basal dendrites of the rat prefrontal cortex. The majority of synaptic contacts in the basilar dendritic tree actually received significant AP-associated electrical and calcium transients.

The Dendritic Cell Major Histocompatibility Complex II (MHC II) Peptidome Derives from a Variety of Processing Pathways and Includes Peptides with a Broad Spectrum of HLA-DM Sensitivity*

PubMed Central

Clement, Cristina C.; Becerra, Aniuska; Yin, Liusong; Zolla, Valerio; Huang, Liling; Merlin, Simone; Follenzi, Antonia; Shaffer, Scott A.; Stern, Lawrence J.; Santambrogio, Laura

2016-01-01

The repertoire of peptides displayed in vivo by MHC II molecules derives from a wide spectrum of proteins produced by different cell types. Although intracellular endosomal processing in dendritic cells and B cells has been characterized for a few antigens, the overall range of processing pathways responsible for generating the MHC II peptidome are currently unclear. To determine the contribution of non-endosomal processing pathways, we eluted and sequenced over 3000 HLA-DR1-bound peptides presented in vivo by dendritic cells. The processing enzymes were identified by reference to a database of experimentally determined cleavage sites and experimentally validated for four epitopes derived from complement 3, collagen II, thymosin β4, and gelsolin. We determined that self-antigens processed by tissue-specific proteases, including complement, matrix metalloproteases, caspases, and granzymes, and carried by lymph, contribute significantly to the MHC II self-peptidome presented by conventional dendritic cells in vivo. Additionally, the presented peptides exhibited a wide spectrum of binding affinity and HLA-DM susceptibility. The results indicate that the HLA-DR1-restricted self-peptidome presented under physiological conditions derives from a variety of processing pathways. Non-endosomal processing enzymes add to the number of epitopes cleaved by cathepsins, altogether generating a wider peptide repertoire. Taken together with HLA-DM-dependent and-independent loading pathways, this ensures that a broad self-peptidome is presented by dendritic cells. This work brings attention to the role of “self-recognition” as a dynamic interaction between dendritic cells and the metabolic/catabolic activities ongoing in every parenchymal organ as part of tissue growth, remodeling, and physiological apoptosis. PMID:26740625

Glutamate-Bound NMDARs Arising from In Vivo-like Network Activity Extend Spatio-temporal Integration in a L5 Cortical Pyramidal Cell Model

PubMed Central

Farinella, Matteo; Ruedt, Daniel T.; Gleeson, Padraig; Lanore, Frederic; Silver, R. Angus

2014-01-01

In vivo, cortical pyramidal cells are bombarded by asynchronous synaptic input arising from ongoing network activity. However, little is known about how such ‘background’ synaptic input interacts with nonlinear dendritic mechanisms. We have modified an existing model of a layer 5 (L5) pyramidal cell to explore how dendritic integration in the apical dendritic tuft could be altered by the levels of network activity observed in vivo. Here we show that asynchronous background excitatory input increases neuronal gain and extends both temporal and spatial integration of stimulus-evoked synaptic input onto the dendritic tuft. Addition of fast and slow inhibitory synaptic conductances, with properties similar to those from dendritic targeting interneurons, that provided a ‘balanced’ background configuration, partially counteracted these effects, suggesting that inhibition can tune spatio-temporal integration in the tuft. Excitatory background input lowered the threshold for NMDA receptor-mediated dendritic spikes, extended their duration and increased the probability of additional regenerative events occurring in neighbouring branches. These effects were also observed in a passive model where all the non-synaptic voltage-gated conductances were removed. Our results show that glutamate-bound NMDA receptors arising from ongoing network activity can provide a powerful spatially distributed nonlinear dendritic conductance. This may enable L5 pyramidal cells to change their integrative properties as a function of local network activity, potentially allowing both clustered and spatially distributed synaptic inputs to be integrated over extended timescales. PMID:24763087

Rapid, directed transport of DC-SIGN clusters in the plasma membrane

PubMed Central

Liu, Ping; Weinreb, Violetta; Ridilla, Marc; Betts, Laurie; Patel, Pratik; de Silva, Aravinda M.; Thompson, Nancy L.; Jacobson, Ken

2017-01-01

C-type lectins, including dendritic cell–specific intercellular adhesion molecule-3–grabbing nonintegrin (DC-SIGN), are all-purpose pathogen receptors that exist in nanoclusters in plasma membranes of dendritic cells. A small fraction of these clusters, obvious from the videos, can undergo rapid, directed transport in the plane of the plasma membrane at average speeds of more than 1 μm/s in both dendritic cells and MX DC-SIGN murine fibroblasts ectopically expressing DC-SIGN. Surprisingly, instantaneous speeds can be considerably greater. In MX DC-SIGN cells, many cluster trajectories are colinear with microtubules that reside close to the ventral membrane, and the microtubule-depolymerizing drug, nocodazole, markedly reduced the areal density of directed movement trajectories, suggesting a microtubule motor–driven transport mechanism; by contrast, latrunculin A, which affects the actin network, did not depress this movement. Rapid, retrograde movement of DC-SIGN may be an efficient mechanism for bringing bound pathogen on the leading edge and projections of dendritic cells to the perinuclear region for internalization and processing. Dengue virus bound to DC-SIGN on dendritic projections was rapidly transported toward the cell center. The existence of this movement within the plasma membrane points to an unexpected lateral transport mechanism in mammalian cells and challenges our current concepts of cortex-membrane interactions. PMID:29134199

Transient potentials in dendritic systems of arbitrary geometry.

PubMed

Butz, E G; Cowan, J D

1974-09-01

A simple graphical calculus is developed that generates analytic solutions for membrane potential transforms at any point on the dendritic tree of neurons with arbitrary dendritic geometries, in response to synaptic "current" inputs. Such solutions permit the computation of transients in neurons with arbitrary geometry and may facilitate analysis of the role of dendrites in such cells.

Neocortical layers I and II of the hedgehog (Erinaceus europaeus). I. Intrinsic organization.

PubMed

Valverde, F; Facal-Valverde, M V

1986-01-01

The intrinsic organization and interlaminar connections in neocortical layers I and II have been studied in adult hedgehogs (Erinaceus europaeus) using the Golgi method. Layer I contains a dense plexus of horizontal fibers, the terminal dendritic bouquets of pyramidal cells of layer II and of underlying layers, and varieties of intrinsic neurons. Four main types of cells were found in layer I. Small horizontal cells represent most probably persisting foetal horizontal cells described for other mammals. Large horizontal cells, tufted cells, and spinous horizontal cells were also found in this layer. Layer II contains primitive pyramidal cells representing the most outstanding feature of the neocortex of the hedgehog. Most pyramidal cells in layer II have two, three or more apical dendrites, richly covered by spines predominating over the basal dendrites. These cells resemble pyramidal cells found in the piriform cortex, hippocampus and other olfactory areas. It is suggested that the presence of these neurons reflects the retention of a primitive character in neocortical evolution. Cells with intrinsic axons were found among pyramidal cells in layer II. These have smooth dendrites penetrating layer I and local axons forming extremely complex terminal arborizations around the bodies and proximal dendritic portions of pyramidal cells. They most probably effect numerous axo-somatic contacts resembling basket cells. The similarity of some axonal terminals with the chandelier type of axonal arborization is discussed. Other varieties of cells located in deep cortical layers and having ascending axons for layers I and II were also studied. It is concluded that the two first neocortical layers represent a level of important integration in this primitive mammal.

Flavonoids from Engineered Tomatoes Inhibit Gut Barrier Pro-inflammatory Cytokines and Chemokines, via SAPK/JNK and p38 MAPK Pathways.

PubMed

Tomlinson, Matthew L; Butelli, Eugenio; Martin, Cathie; Carding, Simon R

2017-01-01

Flavonoids are a diverse group of plant secondary metabolites, known to reduce inflammatory bowel disease symptoms. How they achieve this is largely unknown. Our study focuses on the gut epithelium as it receives high topological doses of dietary constituents, maintains gut homeostasis, and orchestrates gut immunity. Dysregulation leads to chronic gut inflammation, via dendritic cell (DC)-driven immune responses. Tomatoes engineered for enriched sets of flavonoids (anthocyanins or flavonols) provided a unique and complex naturally consumed food matrix to study the effect of diet on chronic inflammation. Primary murine colonic epithelial cell-based inflammation assays consist of chemokine induction, apoptosis and proliferation, and effects on kinase pathways. Primary murine leukocytes and DCs were used to assay effects on transmigration. A murine intestinal cell line was used to assay wound healing. Engineered tomato extracts (enriched in anthocyanins or flavonols) showed strong and specific inhibitory effects on a set of key epithelial pro-inflammatory cytokines and chemokines. Chemotaxis assays showed a resulting reduction in the migration of primary leukocytes and DCs. Activation of epithelial cell SAPK/JNK and p38 MAPK signaling pathways were specifically inhibited. The epithelial wound healing-associated STAT3 pathway was unaffected. Cellular migration, proliferation, and apoptosis assays confirmed that wound healing processes were not affected by flavonoids. We show flavonoids target epithelial pro-inflammatory kinase pathways, inhibiting chemotactic signals resulting in reduced leukocyte and DC chemotaxis. Thus, both anthocyanins and flavonols modulate epithelial cells to become hyporesponsive to bacterial stimulation. Our results identify a viable mechanism to explain the in vivo anti-inflammatory effects of flavonoids.

Dendro-dendritic interactions between motion-sensitive large-field neurons in the fly.

PubMed

Haag, Juergen; Borst, Alexander

2002-04-15

For visual course control, flies rely on a set of motion-sensitive neurons called lobula plate tangential cells (LPTCs). Among these cells, the so-called CH (centrifugal horizontal) cells shape by their inhibitory action the receptive field properties of other LPTCs called FD (figure detection) cells specialized for figure-ground discrimination based on relative motion. Studying the ipsilateral input circuitry of CH cells by means of dual-electrode and combined electrical-optical recordings, we find that CH cells receive graded input from HS (large-field horizontal system) cells via dendro-dendritic electrical synapses. This particular wiring scheme leads to a spatial blur of the motion image on the CH cell dendrite, and, after inhibiting FD cells, to an enhancement of motion contrast. This could be crucial for enabling FD cells to discriminate object from self motion.

Transcriptional regulation of neuronal polarity and morphogenesis in the mammalian brain

PubMed Central

de la Torre-Ubieta, Luis; Bonni, Azad

2012-01-01

The highly specialized morphology of a neuron, typically consisting of a long axon and multiple branching dendrites, lies at the core of the principle of dynamic polarization, whereby information flows from dendrites toward the soma and to the axon. For more than a century neuroscientists have been fascinated by how shape is important for neuronal function and how neurons acquire their characteristic morphology. During the past decade, substantial progress has been made in our understanding of the molecular underpinnings of neuronal polarity and morphogenesis. In these studies, transcription factors have emerged as key players governing multiple aspects of neuronal morphogenesis from neuronal polarization and migration to axon growth and pathfinding to dendrite growth and branching to synaptogenesis. In this review, we will highlight the role of transcription factors in shaping neuronal morphology with emphasis on recent literature in mammalian systems. PMID:21982366

High temperature (900-1300 C) mechanical behaviour of dendritic web grown silicon ribbons - Strain rate and temperature dependence of the yield stress

NASA Technical Reports Server (NTRS)

Mathews, V. K.; Gross, T. S.

1987-01-01

The mechanical behavior of dendritic web Si ribbons close the melting point was studied experimentally. The goal of the study was to generate data for modeling the generation of stresses and dislocation structures during growth of dendritic web Si ribbons, thereby permitting modifications to the production process, i.e., the temperature profile, to lower production costs for the photovoltaic ribbons. A laser was used to cut specimens in the direction of growth of sample ribbons, which were then subjected to tensile tests at temperatures up to 1300 C in an Ar atmosphere. The tensile strengths of the samples increased when the temperature rose above 1200 C, a phenomena which was attributed to the diffusion of oxygen atoms to the quasi-dislocation sites. The migration to the potential dislocations sites effectively locked the dislocations.

Cell-Mediated Drugs Delivery

PubMed Central

Batrakova, Elena V.; Gendelman, Howard E.; Kabanov, Alexander V.

2011-01-01

INTRODUCTION Drug targeting to sites of tissue injury, tumor or infection with limited toxicity is the goal for successful pharmaceutics. Immunocytes (including mononuclear phagocytes (dendritic cells, monocytes and macrophages), neutrophils, and lymphocytes) are highly mobile; they can migrate across impermeable barriers and release their drug cargo at sites of infection or tissue injury. Thus immune cells can be exploited as trojan horses for drug delivery. AREAS COVERED IN THIS REVIEW This paper reviews how immunocytes laden with drugs can cross the blood brain or blood tumor barriers, to facilitate treatments for infectious diseases, injury, cancer, or inflammatory diseases. The promises and perils of cell-mediated drug delivery are reviewed, with examples of how immunocytes can be harnessed to improve therapeutic end points. EXPERT OPINION Using cells as delivery vehicles enables targeted drug transport, and prolonged circulation times, along with reductions in cell and tissue toxicities. Such systems for drug carriage and targeted release represent a novel disease combating strategy being applied to a spectrum of human disorders. The design of nanocarriers for cell-mediated drug delivery may differ from those used for conventional drug delivery systems; nevertheless, engaging different defense mechanisms into drug delivery may open new perspectives for the active delivery of drugs. PMID:21348773

Olfactory epithelium influences the orientation of mitral cell dendrites during development.

PubMed

López-Mascaraque, Laura; García, Concepción; Blanchart, Albert; De Carlos, Juan A

2005-02-01

We have established previously that, although the olfactory epithelium is absent in the homozygous Pax-6 mutant mouse, an olfactory bulb-like structure (OBLS) does develop. Moreover, this OBLS contains cells that correspond to mitral cells, the primary projection neurons in the olfactory bulb. The current study aimed to address whether the dendrites of mitral cells in the olfactory bulb or in the OBLS mitral-like cells, exhibit a change in orientation in the presence of the olfactory epithelium. The underlying hypothesis is that the olfactory epithelium imparts a trophic signal on mitral and mitral-like cell that influences the growth of their primary dendrites, orientating them toward the surface of the olfactory bulb. Hence, we cultured hemibrains from wild-type and Pax 6 mutant mice from two different embryonic stages (embryonic days 14 and 15) either alone or in coculture with normal olfactory epithelial explants or control tissue (cerebellum). Our results indicate that the final dendritic orientation of mitral and mitral-like cells is directly influenced both by age and indeed by the presence of the olfactory epithelium. Copyright 2004 Wiley-Liss, Inc.

Effects of a new bifunctional psoralen, 4,4',5'-trimethylazapsoralen and ultraviolet-A radiation on murine dendritic epidermal cells.

PubMed

Aubin, F; Alcalay, J; Dall'Acqua, F; Kripke, M L

1990-06-01

Although some psoralens are therapeutically active in the treatment of cutaneous hyperproliferative diseases when combined with UVA (320-400 nm) radiation, the toxic effects of these compounds have led physicians to seek new photochemotherapeutic agents. One such agent is 4,4',5'-trimethylazapsoralen (TMAP), a new bifunctional psoralen compound. We investigated the effects of repetitive treatments with TMAP plus UVA radiation on the number of dendritic immune cells in murine epidermis and on the induction of phototoxicity. Mice treated 3 times per week for 4 weeks with 129 microgram TMAP plus 10 kJ/m2 UVA radiation exhibited no gross or microscopic evidence of phototoxicity. During this treatment, the numbers of ATPase+, Ia+, and Thy-l+ dendritic epidermal cells were greatly reduced, and by the end of the treatment period, few dendritic immune cells could be detected. We conclude that morphological alterations of cutaneous immune cells can occur in the absence of overt phototoxicity, and that TMAP plus low-dose UVA radiation decreases the numbers of detectable Langerhans cells and Thy-1+ cells in murine skin.

Generating synchrony from the asynchronous: compensation for cochlear traveling wave delays by the dendrites of individual brainstem neurons

PubMed Central

McGinley, Matthew J.; Liberman, M. Charles; Bal, Ramazan; Oertel, Donata

2012-01-01

Broadband transient sounds, such as clicks and consonants, activate a traveling wave in the cochlea. This wave evokes firing in auditory nerve fibers that are tuned to high frequencies several milliseconds earlier than in fibers tuned to low frequencies. Despite this substantial traveling wave delay, octopus cells in the brainstem receive broadband input and respond to clicks with submillisecond temporal precision. The dendrites of octopus cells lie perpendicular to the tonotopically organized array of auditory nerve fibers, placing the earliest arriving inputs most distally and the latest arriving closest to the soma. Here, we test the hypothesis that the topographic arrangement of synaptic inputs on dendrites of octopus cells allows octopus cells to compensate the traveling wave delay. We show that in mice the full cochlear traveling wave delay is 1.6 ms. Because the dendrites of each octopus cell spread across about one third of the tonotopic axis, a click evokes a soma directed sweep of synaptic input lasting 0.5 ms in individual octopus cells. Morphologically and biophysically realistic, computational models of octopus cells show that soma-directed sweeps with durations matching in vivo measurements result in the largest and sharpest somatic excitatory postsynaptic potentials (EPSPs). A low input resistance and activation of a low-voltage-activated potassium conductance that are characteristic of octopus cells are important determinants of sweep sensitivity. We conclude that octopus cells have dendritic morphologies and biophysics tailored to accomplish the precise encoding of broadband transient sounds. PMID:22764237

Dendritic Cell-Mediated T Cell Proliferation -A Functional Bioindicator of Inflammatory Source-Specific Particulate Matter

EPA Science Inventory

Previously we found that dendritic cells (DC) were sensitive functional bioindicators of ambient PM (APM) exposure mediating Th2-allergic inflammation in the draining lymph nodes. Here, the ability of bone-marrow-derived DC (DC) and putative BM-derived basophils (Ba) to present a...

Phenotypic, ultra-structural and functional characterization of bovine peripheral blood dendritic cell subsets

USDA-ARS?s Scientific Manuscript database

Dendritic cells (DC) are multifunctional cells that bridge the gap between innate and adaptive immune systems. In bovine, significant information is lacking on the precise identity and role of peripheral blood DC subsets. In this study, we identify and characterize bovine peripheral blood DC subsets...

Development of the Human Cortex and the Concept of "Critical" or "Sensitive" Periods

ERIC Educational Resources Information Center

Uylings, H. B. M.

2006-01-01

This review describes the prenatal and postnatal development of the human cortex. Neurogenesis, neuronal migration, dendrite maturation, synaptogenesis, and white matter development are discussed. In addition, the concept of "critical" or "sensitive" periods is discussed as well as genetic and environmental influences (Nature-Nurture). The effects…

Astragalus Root and Elderberry Fruit Extracts Enhance the IFN-β Stimulatory Effects of Lactobacillus acidophilus in Murine-Derived Dendritic Cells

PubMed Central

Frøkiær, Hanne; Henningsen, Louise; Metzdorff, Stine Broeng; Weiss, Gudrun; Roller, Marc; Flanagan, John; Fromentin, Emilie; Ibarra, Alvin

2012-01-01

Many foods and food components boost the immune system, but little data are available regarding the mechanisms by which they do. Bacterial strains have disparate effects in stimulating the immune system. Indendritic cells, the gram-negative bacteria Escherichia coli upregulates proinflammatory cytokines, whereas gram-positive Lactobacillus acidophilus induces a robust interferon (IFN)-β response. The immune-modulating effects of astragalus root and elderberry fruit extracts were examined in bone marrow-derived murine dendritic cells that were stimulated with L. acidophilus or E. coli. IFN-β and other cytokines were measured by ELISA and RT-PCR. Endocytosis of fluorescence-labeled dextran and L. acidophilus in the presence of elderberry fruit or astragalus root extract was evaluated in dendritic cells. Our results show that both extracts enhanced L. acidophilus-induced IFN-β production and slightly decreased the proinflammatory response to E. coli. The enhanced IFN-β production was associated with upregulation of toll-like receptor 3 and to a varying degree, the cytokines IL-12, IL-6, IL-1β and TNF-α. Both extracts increased endocytosis in immature dendritic cells, and only slightly influenced the viability of the cells. In conclusion, astragalus root and elderberry fruit extracts increase the IFN-β inducing activity of L. acidophilus in dendritic cells, suggesting that they may exert antiviral and immune-enhancing activity. PMID:23118903

Evaluation of Immune Responses Mediated by Listeria-Stimulated Human Dendritic Cells: Implications for Cancer Vaccine Therapy

DTIC Science & Technology

2013-07-01

by Listeria -Stimulated Human Dendritic Cells: Implications for Cancer Vaccine Therapy PRINCIPAL INVESTIGATOR: David J. Chung, MD, PhD...2013 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER W81XWH-11-1-0384 Evaluation of Immune Responses Mediated by Listeria -Stimulated Human Dendritic...Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT The purpose of this project is to study the immunomodulatory effect of Listeria on human

Chronic alcohol exposure affects the cell components involved in membrane traffic in neuronal dendrites.

PubMed

Romero, Ana M; Renau-Piqueras, Jaime; Marín, M Pilar; Esteban-Pretel, Guillermo

2015-01-01

The specific traffic of the membrane components in neurons is a major requirement to establish and maintain neuronal domains-the axonal and the somatodendritic domains-and their polarized morphology. Unlike axons, dendrites contain membranous organelles, which are involved in the secretory pathway, including the endoplasmic reticulum, the Golgi apparatus and post-Golgi apparatus carriers, the cytoskeleton, and plasma membrane. A variety of molecules and factors are also involved in this process. Previous studies have shown that chronic alcohol exposure negatively affects several of these cell components, such as the Golgi apparatus or cytoskeleton in neurons. Yet very little information is available on the possible effects of this exposure on the remaining cell elements involved in intracellular trafficking in neurons, particularly in dendrites. By qualitative and quantitative electron microscopy, immunofluorescence and immunoblotting, we herein show that chronic exposure to moderate levels (30 mM) of ethanol in cultured neurons reduces the volume and surface density of the rough endoplasmic reticulum, and increases the levels of GRP78, a chaperone involved in endoplasmic reticulum stress. Ethanol also significantly diminishes the proportion of neurons that show an extension of Golgi into dendrites and dendritic Golgi outposts, a structure present exclusively in longer, thicker apical dendrites. Both Golgi apparatus types were also fragmented into a large number of cells. We also investigated the effect of alcohol on the levels of microtubule-based motor proteins KIF5, KIF17, KIFC2, dynein, and myosin IIb, responsible for transporting different cargoes in dendrites. Of these, alcohol differently affects several of them by lowering dynein and raising KIF5, KIFC2, and myosin IIb. These results, together with other previously published ones, suggest that practically all the protein trafficking steps in dendrites are altered to a greater or lesser extent by chronic alcohol exposure in neuronal cells, which may have negative repercussions for the development and maintenance of their polarized morphology and function.

Musical representation of dendritic spine distribution: a new exploratory tool.

PubMed

Toharia, Pablo; Morales, Juan; de Juan, Octavio; Fernaud, Isabel; Rodríguez, Angel; DeFelipe, Javier

2014-04-01

Dendritic spines are small protrusions along the dendrites of many types of neurons in the central nervous system and represent the major target of excitatory synapses. For this reason, numerous anatomical, physiological and computational studies have focused on these structures. In the cerebral cortex the most abundant and characteristic neuronal type are pyramidal cells (about 85 % of all neurons) and their dendritic spines are the main postsynaptic target of excitatory glutamatergic synapses. Thus, our understanding of the synaptic organization of the cerebral cortex largely depends on the knowledge regarding synaptic inputs to dendritic spines of pyramidal cells. Much of the structural data on dendritic spines produced by modern neuroscience involves the quantitative analysis of image stacks from light and electron microscopy, using standard statistical and mathematical tools and software developed to this end. Here, we present a new method with musical feedback for exploring dendritic spine morphology and distribution patterns in pyramidal neurons. We demonstrate that audio analysis of spiny dendrites with apparently similar morphology may "sound" quite different, revealing anatomical substrates that are not apparent from simple visual inspection. These morphological/music translations may serve as a guide for further mathematical analysis of the design of the pyramidal neurons and of spiny dendrites in general.

Dendrite architecture organized by transcriptional control of the F-actin nucleator Spire.

PubMed

Ferreira, Tiago; Ou, Yimiao; Li, Sally; Giniger, Edward; van Meyel, Donald J

2014-02-01

The architectures of dendritic trees are crucial for the wiring and function of neuronal circuits because they determine coverage of receptive territories, as well as the nature and strength of sensory or synaptic inputs. Here, we describe a cell-intrinsic pathway sculpting dendritic arborization (da) neurons in Drosophila that requires Longitudinals Lacking (Lola), a BTB/POZ transcription factor, and its control of the F-actin cytoskeleton through Spire (Spir), an actin nucleation protein. Loss of Lola from da neurons reduced the overall length of dendritic arbors, increased the expression of Spir, and produced inappropriate F-actin-rich dendrites at positions too near the cell soma. Selective removal of Lola from only class IV da neurons decreased the evasive responses of larvae to nociception. The increased Spir expression contributed to the abnormal F-actin-rich dendrites and the decreased nocifensive responses because both were suppressed by reduced dose of Spir. Thus, an important role of Lola is to limit expression of Spir to appropriate levels within da neurons. We found Spir to be expressed in dendritic arbors and to be important for their development. Removal of Spir from class IV da neurons reduced F-actin levels and total branch number, shifted the position of greatest branch density away from the cell soma, and compromised nocifensive behavior. We conclude that the Lola-Spir pathway is crucial for the spatial arrangement of branches within dendritic trees and for neural circuit function because it provides balanced control of the F-actin cytoskeleton.

Branching angles of pyramidal cell dendrites follow common geometrical design principles in different cortical areas.

PubMed

Bielza, Concha; Benavides-Piccione, Ruth; López-Cruz, Pedro; Larrañaga, Pedro; DeFelipe, Javier

2014-08-01

Unraveling pyramidal cell structure is crucial to understanding cortical circuit computations. Although it is well known that pyramidal cell branching structure differs in the various cortical areas, the principles that determine the geometric shapes of these cells are not fully understood. Here we analyzed and modeled with a von Mises distribution the branching angles in 3D reconstructed basal dendritic arbors of hundreds of intracellularly injected cortical pyramidal cells in seven different cortical regions of the frontal, parietal, and occipital cortex of the mouse. We found that, despite the differences in the structure of the pyramidal cells in these distinct functional and cytoarchitectonic cortical areas, there are common design principles that govern the geometry of dendritic branching angles of pyramidal cells in all cortical areas.

Branching angles of pyramidal cell dendrites follow common geometrical design principles in different cortical areas

PubMed Central

Bielza, Concha; Benavides-Piccione, Ruth; López-Cruz, Pedro; Larrañaga, Pedro; DeFelipe, Javier

2014-01-01

Unraveling pyramidal cell structure is crucial to understanding cortical circuit computations. Although it is well known that pyramidal cell branching structure differs in the various cortical areas, the principles that determine the geometric shapes of these cells are not fully understood. Here we analyzed and modeled with a von Mises distribution the branching angles in 3D reconstructed basal dendritic arbors of hundreds of intracellularly injected cortical pyramidal cells in seven different cortical regions of the frontal, parietal, and occipital cortex of the mouse. We found that, despite the differences in the structure of the pyramidal cells in these distinct functional and cytoarchitectonic cortical areas, there are common design principles that govern the geometry of dendritic branching angles of pyramidal cells in all cortical areas. PMID:25081193

Dendritic spikes amplify the synaptic signal to enhance detection of motion in a simulation of the direction-selective ganglion cell.

PubMed

Schachter, Michael J; Oesch, Nicholas; Smith, Robert G; Taylor, W Rowland

2010-08-19

The On-Off direction-selective ganglion cell (DSGC) in mammalian retinas responds most strongly to a stimulus moving in a specific direction. The DSGC initiates spikes in its dendritic tree, which are thought to propagate to the soma with high probability. Both dendritic and somatic spikes in the DSGC display strong directional tuning, whereas somatic PSPs (postsynaptic potentials) are only weakly directional, indicating that spike generation includes marked enhancement of the directional signal. We used a realistic computational model based on anatomical and physiological measurements to determine the source of the enhancement. Our results indicate that the DSGC dendritic tree is partitioned into separate electrotonic regions, each summing its local excitatory and inhibitory synaptic inputs to initiate spikes. Within each local region the local spike threshold nonlinearly amplifies the preferred response over the null response on the basis of PSP amplitude. Using inhibitory conductances previously measured in DSGCs, the simulation results showed that inhibition is only sufficient to prevent spike initiation and cannot affect spike propagation. Therefore, inhibition will only act locally within the dendritic arbor. We identified the role of three mechanisms that generate directional selectivity (DS) in the local dendritic regions. First, a mechanism for DS intrinsic to the dendritic structure of the DSGC enhances DS on the null side of the cell's dendritic tree and weakens it on the preferred side. Second, spatially offset postsynaptic inhibition generates robust DS in the isolated dendritic tips but weak DS near the soma. Third, presynaptic DS is apparently necessary because it is more robust across the dendritic tree. The pre- and postsynaptic mechanisms together can overcome the local intrinsic DS. These local dendritic mechanisms can perform independent nonlinear computations to make a decision, and there could be analogous mechanisms within cortical circuitry.

Transient Potentials in Dendritic Systems of Arbitrary Geometry

PubMed Central

Butz, Edward G.; Cowan, Jack D.

1974-01-01

A simple graphical calculus is developed that generates analytic solutions for membrane potential transforms at any point on the dendritic tree of neurons with arbitrary dendritic geometries, in response to synaptic “current” inputs. Such solutions permit the computation of transients in neurons with arbitrary geometry and may facilitate analysis of the role of dendrites in such cells. PMID:4416699

Depletion of kidney CD11c+ F4/80+ cells impairs the recovery process in ischaemia/reperfusion-induced acute kidney injury.

PubMed

Kim, Myung-Gyu; Boo, Chang Su; Ko, Yoon Sook; Lee, Hee Young; Cho, Won Yong; Kim, Hyoung Kyu; Jo, Sang-Kyung

2010-09-01

Recent studies provided evidence of the potential role of CD11c(+) F4/80(+) dendritic subset in mediating injury and repair. The purpose of this study was to examine the role of kidney CD11c(+) F4/80(+) dendritic subset in the recovery phase of ischaemia/reperfusion injury (IRI). Following ischaemia/reperfusion (I/R), liposome clodronate or phosphate buffered saline (PBS) was administered, and on day 7 biochemical and histologic kidney damage was assessed. Activation and depletion of CD11c(+) F4/80(+) dendritic subset were confirmed by flow cytometry. Isolation of kidney CD11c(+) cells on days 1 and 7 with in vitro culture for measuring cytokines was performed to define functional characteristics of these cells, and adoptive transfer of CD11c(+) cells was also done. Following kidney IRI, the percentage of CD11c(+) F4/80(+) kidney dendritic cell subset that co-expresses maturation marker increased. Liposome clodronate injection after I/R resulted in preferential depletion of CD11c(+) F4/80(+) kidney dendritic subset, and depletion of these cells was associated with persistent kidney injury, more apoptosis, inflammation and impaired tubular cell proliferation. CD11c(+) F4/80(+) cell depletion was also associated with higher tissue levels of pro-inflammatory cytokines and lower level of IL-10, indicating the persistence of inflammatory milieu. Isolated kidney CD11c(+) cells on day 7 showed different phenotype with increased production of IL-10 compared with those on day 1. Adoptive transfer of CD11c(+) cells partially reversed impaired tissue recovery. Our results suggest that kidney CD11c(+) F4/80(+) dendritic subset might contribute to the recovery process by dynamic phenotypic change from pro-inflammatory to anti-inflammatory with modulation of immune response.

High dendritic expression of Ih in the proximity of the axon origin controls the integrative properties of nigral dopamine neurons.

PubMed

Engel, Dominique; Seutin, Vincent

2015-11-15

The hyperpolarization-activated cation current Ih is expressed in dopamine neurons of the substantia nigra, but the subcellular distribution of the current and its role in synaptic integration remain unknown. We used cell-attached patch recordings to determine the localization profile of Ih along the somatodendritic axis of nigral dopamine neurons in slices from young rats. Ih density is higher in axon-bearing dendrites, in a membrane area close to the axon origin, than in the soma and axon-lacking dendrites. Dual current-clamp recordings revealed a similar contribution of Ih to the waveform of single excitatory postsynaptic potentials throughout the somatodendritic domain. The Ih blocker ZD 7288 increased the temporal summation in all dendrites with a comparable effect in axon- and non-axon dendrites. The strategic position of Ih in the proximity of the axon may influence importantly transitions between pacemaker and bursting activities and consequently the downstream release of dopamine. Dendrites of most neurons express voltage-gated ion channels in their membrane. In combination with passive properties, active currents confer to dendrites a high computational potential. The hyperpolarization-activated cation current Ih present in the dendrites of some pyramidal neurons affects their membrane and integration properties, synaptic plasticity and higher functions such as memory. A gradient of increasing h-channel density towards distal dendrites has been found to be responsible for the location independence of excitatory postsynaptic potential (EPSP) waveform and temporal summation in cortical and hippocampal pyramidal cells. However, reports on other cell types revealed that smoother gradients or even linear distributions of Ih can achieve homogeneous temporal summation. Although the existence of a robust, slowly activating Ih current has been repeatedly demonstrated in nigral dopamine neurons, its subcellular distribution and precise role in synaptic integration are unknown. Using cell-attached patch-clamp recordings, we find a higher Ih current density in the axon-bearing dendrite than in the soma or in dendrites without axon in nigral dopamine neurons. Ih is mainly concentrated in the dendritic membrane area surrounding the axon origin and decreases with increasing distances from this site. Single EPSPs and temporal summation are similarly affected by blockade of Ih in axon- and non-axon-bearing dendrites. The presence of Ih close to the axon is pivotal to control the integrative functions and the output signal of dopamine neurons and may consequently influence the downstream coding of movement. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Different tissue phagocytes sample apoptotic cells to direct distinct homeostasis programs.

PubMed

Cummings, Ryan J; Barbet, Gaetan; Bongers, Gerold; Hartmann, Boris M; Gettler, Kyle; Muniz, Luciana; Furtado, Glaucia C; Cho, Judy; Lira, Sergio A; Blander, J Magarian

2016-11-24

Recognition and removal of apoptotic cells by professional phagocytes, including dendritic cells and macrophages, preserves immune self-tolerance and prevents chronic inflammation and autoimmune pathologies. The diverse array of phagocytes that reside within different tissues, combined with the necessarily prompt nature of apoptotic cell clearance, makes it difficult to study this process in situ. The full spectrum of functions executed by tissue-resident phagocytes in response to homeostatic apoptosis, therefore, remains unclear. Here we show that mouse apoptotic intestinal epithelial cells (IECs), which undergo continuous renewal to maintain optimal barrier and absorptive functions, are not merely extruded to maintain homeostatic cell numbers, but are also sampled by a single subset of dendritic cells and two macrophage subsets within a well-characterized network of phagocytes in the small intestinal lamina propria. Characterization of the transcriptome within each subset before and after in situ sampling of apoptotic IECs revealed gene expression signatures unique to each phagocyte, including macrophage-specific lipid metabolism and amino acid catabolism, and a dendritic-cell-specific program of regulatory CD4 + T-cell activation. A common 'suppression of inflammation' signature was noted, although the specific genes and pathways involved varied amongst dendritic cells and macrophages, reflecting specialized functions. Apoptotic IECs were trafficked to mesenteric lymph nodes exclusively by the dendritic cell subset and served as critical determinants for the induction of tolerogenic regulatory CD4 + T-cell differentiation. Several of the genes that were differentially expressed by phagocytes bearing apoptotic IECs overlapped with susceptibility genes for inflammatory bowel disease. Collectively, these findings provide new insights into the consequences of apoptotic cell sampling, advance our understanding of how homeostasis is maintained within the mucosa and set the stage for development of novel therapeutics to alleviate chronic inflammatory diseases such as inflammatory bowel disease.

Dendrites In Vitro and In Vivo Contain Microtubules of Opposite Polarity and Axon Formation Correlates with Uniform Plus-End-Out Microtubule Orientation.

PubMed

Yau, Kah Wai; Schätzle, Philipp; Tortosa, Elena; Pagès, Stéphane; Holtmaat, Anthony; Kapitein, Lukas C; Hoogenraad, Casper C

2016-01-27

In cultured vertebrate neurons, axons have a uniform arrangement of microtubules with plus-ends distal to the cell body (plus-end-out), whereas dendrites contain mixed polarity orientations with both plus-end-out and minus-end-out oriented microtubules. Rather than non-uniform microtubules, uniparallel minus-end-out microtubules are the signature of dendrites in Drosophila and Caenorhabditis elegans neurons. To determine whether mixed microtubule organization is a conserved feature of vertebrate dendrites, we used live-cell imaging to systematically analyze microtubule plus-end orientations in primary cultures of rat hippocampal and cortical neurons, dentate granule cells in mouse organotypic slices, and layer 2/3 pyramidal neurons in the somatosensory cortex of living mice. In vitro and in vivo, all microtubules had a plus-end-out orientation in axons, whereas microtubules in dendrites had mixed orientations. When dendritic microtubules were severed by laser-based microsurgery, we detected equal numbers of plus- and minus-end-out microtubule orientations throughout the dendritic processes. In dendrites, the minus-end-out microtubules were generally more stable and comparable with plus-end-out microtubules in axons. Interestingly, at early stages of neuronal development in nonpolarized cells, newly formed neurites already contained microtubules of opposite polarity, suggesting that the establishment of uniform plus-end-out microtubules occurs during axon formation. We propose a model in which the selective formation of uniform plus-end-out microtubules in the axon is a critical process underlying neuronal polarization. Live-cell imaging was used to systematically analyze microtubule organization in primary cultures of rat hippocampal neurons, dentate granule cells in mouse organotypic slices, and layer 2/3 pyramidal neuron in somatosensory cortex of living mice. In vitro and in vivo, all microtubules have a plus-end-out orientation in axons, whereas microtubules in dendrites have mixed orientations. Interestingly, newly formed neurites of nonpolarized neurons already contain mixed microtubules, and the specific organization of uniform plus-end-out microtubules only occurs during axon formation. Based on these findings, the authors propose a model in which the selective formation of uniform plus-end-out microtubules in the axon is a critical process underlying neuronal polarization. Copyright © 2016 the authors 0270-6474/16/361072-15$15.00/0.

Modeling somatic and dendritic spike mediated plasticity at the single neuron and network level.

PubMed

Bono, Jacopo; Clopath, Claudia

2017-09-26

Synaptic plasticity is thought to be the principal neuronal mechanism underlying learning. Models of plastic networks typically combine point neurons with spike-timing-dependent plasticity (STDP) as the learning rule. However, a point neuron does not capture the local non-linear processing of synaptic inputs allowed for by dendrites. Furthermore, experimental evidence suggests that STDP is not the only learning rule available to neurons. By implementing biophysically realistic neuron models, we study how dendrites enable multiple synaptic plasticity mechanisms to coexist in a single cell. In these models, we compare the conditions for STDP and for synaptic strengthening by local dendritic spikes. We also explore how the connectivity between two cells is affected by these plasticity rules and by different synaptic distributions. Finally, we show that how memory retention during associative learning can be prolonged in networks of neurons by including dendrites.Synaptic plasticity is the neuronal mechanism underlying learning. Here the authors construct biophysical models of pyramidal neurons that reproduce observed plasticity gradients along the dendrite and show that dendritic spike dependent LTP which is predominant in distal sections can prolong memory retention.

Transforming growth factor-beta controls T helper type 1 cell development through regulation of natural killer cell interferon-gamma.

PubMed

Laouar, Yasmina; Sutterwala, Fayyaz S; Gorelik, Leonid; Flavell, Richard A

2005-06-01

Interferon-gamma and interleukin 12 produced by the innate arm of the immune system are important regulators of T helper type 1 (T(H)1) cell development, but signals that negatively regulate their expression remain controversial. Here we show that transforming growth factor-beta (TGF-beta) controlled T(H)1 differentiation through the regulation of interferon-gamma produced by natural killer (NK) cells. Blockade of TGF-beta signaling in NK cells caused the accumulation of a large pool of NK cells secreting copious interferon-gamma, responsible for T(H)1 differentiation and protection from leishmania infection. In contrast, blockade of TGF-beta signaling in dendritic cells did not affect dendritic cell homeostasis or interleukin 12 production, thus indicating a previously undescribed demarcation of the function of TGF-beta in NK cells versus dendritic cells.

Active Dendrites and Differential Distribution of Calcium Channels Enable Functional Compartmentalization of Golgi Cells.

PubMed

Rudolph, Stephanie; Hull, Court; Regehr, Wade G

2015-11-25

Interneurons are essential to controlling excitability, timing, and synaptic integration in neuronal networks. Golgi cells (GoCs) serve these roles at the input layer of the cerebellar cortex by releasing GABA to inhibit granule cells (grcs). GoCs are excited by mossy fibers (MFs) and grcs and provide feedforward and feedback inhibition to grcs. Here we investigate two important aspects of GoC physiology: the properties of GoC dendrites and the role of calcium signaling in regulating GoC spontaneous activity. Although GoC dendrites are extensive, previous studies concluded they are devoid of voltage-gated ion channels. Hence, the current view holds that somatic voltage signals decay passively within GoC dendrites, and grc synapses onto distal dendrites are not amplified and are therefore ineffective at firing GoCs because of strong passive attenuation. Using whole-cell recording and calcium imaging in rat slices, we find that dendritic voltage-gated sodium channels allow somatic action potentials to activate voltage-gated calcium channels (VGCCs) along the entire dendritic length, with R-type and T-type VGCCs preferentially located distally. We show that R- and T-type VGCCs located in the dendrites can boost distal synaptic inputs and promote burst firing. Active dendrites are thus critical to the regulation of GoC activity, and consequently, to the processing of input to the cerebellar cortex. In contrast, we find that N-type channels are preferentially located near the soma, and control the frequency and pattern of spontaneous firing through their close association with calcium-activated potassium (KCa) channels. Thus, VGCC types are differentially distributed and serve specialized functions within GoCs. Interneurons are essential to neural processing because they modulate excitability, timing, and synaptic integration within circuits. At the input layer of the cerebellar cortex, a single type of interneuron, the Golgi cell (GoC), carries these functions. The extent of inhibition depends on both spontaneous activity of GoCs and the excitatory synaptic input they receive. In this study, we find that different types of calcium channels are differentially distributed, with dendritic calcium channels being activated by somatic activity, boosting synaptic inputs and enabling bursting, and somatic calcium cannels promoting regular firing. We therefore challenge the current view that GoC dendrites are passive and identify the mechanisms that contribute to GoCs regulating the flow of sensory information in the cerebellar cortex. Copyright © 2015 the authors 0270-6474/15/3515492-13$15.00/0.

Neuropil threads occur in dendrites of tangle-bearing nerve cells.

PubMed

Braak, H; Braak, E

1988-01-01

Transparent Golgi preparations counterstained for Alzheimer's neurofibrillary changes rendered possible the demonstration of neuropil threads in defined cellular processes. Only dendrites of tangle-bearing cortical nerve cells were found to contain neuropil threads. Processes of glial cells as well as axons present in the material were devoid of neuropil threads.

Dendritic cells control fibroblastic reticular network tension and lymph node expansion.

PubMed

Acton, Sophie E; Farrugia, Aaron J; Astarita, Jillian L; Mourão-Sá, Diego; Jenkins, Robert P; Nye, Emma; Hooper, Steven; van Blijswijk, Janneke; Rogers, Neil C; Snelgrove, Kathryn J; Rosewell, Ian; Moita, Luis F; Stamp, Gordon; Turley, Shannon J; Sahai, Erik; Reis e Sousa, Caetano

2014-10-23

After immunogenic challenge, infiltrating and dividing lymphocytes markedly increase lymph node cellularity, leading to organ expansion. Here we report that the physical elasticity of lymph nodes is maintained in part by podoplanin (PDPN) signalling in stromal fibroblastic reticular cells (FRCs) and its modulation by CLEC-2 expressed on dendritic cells. We show in mouse cells that PDPN induces actomyosin contractility in FRCs via activation of RhoA/C and downstream Rho-associated protein kinase (ROCK). Engagement by CLEC-2 causes PDPN clustering and rapidly uncouples PDPN from RhoA/C activation, relaxing the actomyosin cytoskeleton and permitting FRC stretching. Notably, administration of CLEC-2 protein to immunized mice augments lymph node expansion. In contrast, lymph node expansion is significantly constrained in mice selectively lacking CLEC-2 expression in dendritic cells. Thus, the same dendritic cells that initiate immunity by presenting antigens to T lymphocytes also initiate remodelling of lymph nodes by delivering CLEC-2 to FRCs. CLEC-2 modulation of PDPN signalling permits FRC network stretching and allows for the rapid lymph node expansion--driven by lymphocyte influx and proliferation--that is the critical hallmark of adaptive immunity.

Elderberry and Elderflower Extracts, Phenolic Compounds, and Metabolites and Their Effect on Complement, RAW 264.7 Macrophages and Dendritic Cells

PubMed Central

Ho, Giang Thanh Thi; Wangensteen, Helle; Barsett, Hilde

2017-01-01

Modulation of complement activity and inhibition of nitric oxide (NO) production by macrophages and dendritic cells may have therapeutic value in inflammatory diseases. Elderberry and elderflower extracts, constituents, and metabolites were investigated for their effects on the complement system, and on NO production in lipopolysaccharide (LPS)-activated RAW 264.7 macrophages and murine dendritic D2SC/I cells. The EtOH crude extracts from elderberry and elderflower and the isolated anthocyanins and procyanidins possessed strong complement fixating activity and strong inhibitory activity on NO production in RAW cells and dendritic cells. Phenolic compounds in the range of 0.1–100 µM showed a dose-dependent inhibition of NO production, with quercetin, rutin, and kaempferol as the most potent ones. Among the metabolites, caffeic acid and 3,4-dihydroxyphenylacetic acid showed the strongest inhibitory effects on NO production in both cell lines, without having cytotoxic effect. Only 4-methylcatechol was cytotoxic at the highest tested concentration (100 µM). Elderberry and elderflower constituents may possess inflammatory modulating activity, which increases their nutritional value. PMID:28282861

Elderberry and Elderflower Extracts, Phenolic Compounds, and Metabolites and Their Effect on Complement, RAW 264.7 Macrophages and Dendritic Cells.

PubMed

Ho, Giang Thanh Thi; Wangensteen, Helle; Barsett, Hilde

2017-03-08

Modulation of complement activity and inhibition of nitric oxide (NO) production by macrophages and dendritic cells may have therapeutic value in inflammatory diseases. Elderberry and elderflower extracts, constituents, and metabolites were investigated for their effects on the complement system, and on NO production in lipopolysaccharide (LPS)-activated RAW 264.7 macrophages and murine dendritic D2SC/I cells. The EtOH crude extracts from elderberry and elderflower and the isolated anthocyanins and procyanidins possessed strong complement fixating activity and strong inhibitory activity on NO production in RAW cells and dendritic cells. Phenolic compounds in the range of 0.1-100 µM showed a dose-dependent inhibition of NO production, with quercetin, rutin, and kaempferol as the most potent ones. Among the metabolites, caffeic acid and 3,4-dihydroxyphenylacetic acid showed the strongest inhibitory effects on NO production in both cell lines, without having cytotoxic effect. Only 4-methylcatechol was cytotoxic at the highest tested concentration (100 µM). Elderberry and elderflower constituents may possess inflammatory modulating activity, which increases their nutritional value.

Foamy Virus Vector-mediated Gene Correction of a Mouse Model of Wiskott–Aldrich Syndrome

PubMed Central

Uchiyama, Toru; Adriani, Marsilio; Jagadeesh, G Jayashree; Paine, Adam; Candotti, Fabio

2012-01-01

The Wiskott–Aldrich syndrome (WAS) is an X-linked disorder characterized by eczema, thrombocytopenia and immunodeficiency. Hematopoietic cell transplantation can cure the disease and gene therapy is being tested as an alternative treatment option. In this study, we assessed the use of foamy virus (FV) vectors as a gene transfer system for WAS, using a Was knockout (KO) mouse model. Preliminary experiments using FV vectors expressing the green fluorescent protein under the transcriptional control of the endogenous WAS promoter or a ubiquitously acting chromatin opening element allowed us to define transduction conditions resulting in high (>40%) and long-term in-vivo marking of blood cells after transplantation. In following experiments, Was KO mice were treated with FV vectors containing the human WAS complementary DNA (cDNA). Transplanted animals expressed the WAS protein (WASp) in T and B lymphocytes, as well as platelets and showed restoration of both T-cell receptor-mediated responses and B-cell migration. We also observed recovery of platelet adhesion and podosome formation in dendritic cells (DCs) of treated mice. These data demonstrate that FV vectors can be effective for hematopoietic stem cell (HSC)-directed gene correction of WAS. PMID:22215016

Variable Action Potential Backpropagation during Tonic Firing and Low-Threshold Spike Bursts in Thalamocortical But Not Thalamic Reticular Nucleus Neurons.

PubMed

Connelly, William M; Crunelli, Vincenzo; Errington, Adam C

2017-05-24

Backpropagating action potentials (bAPs) are indispensable in dendritic signaling. Conflicting Ca 2+ -imaging data and an absence of dendritic recording data means that the extent of backpropagation in thalamocortical (TC) and thalamic reticular nucleus (TRN) neurons remains unknown. Because TRN neurons signal electrically through dendrodendritic gap junctions and possibly via chemical dendritic GABAergic synapses, as well as classical axonal GABA release, this lack of knowledge is problematic. To address this issue, we made two-photon targeted patch-clamp recordings from rat TC and TRN neuron dendrites to measure bAPs directly. These recordings reveal that "tonic"' and low-threshold-spike (LTS) "burst" APs in both cell types are always recorded first at the soma before backpropagating into the dendrites while undergoing substantial distance-dependent dendritic amplitude attenuation. In TC neurons, bAP attenuation strength varies according to firing mode. During LTS bursts, somatic AP half-width increases progressively with increasing spike number, allowing late-burst spikes to propagate more efficiently into the dendritic tree compared with spikes occurring at burst onset. Tonic spikes have similar somatic half-widths to late burst spikes and undergo similar dendritic attenuation. In contrast, in TRN neurons, AP properties are unchanged between LTS bursts and tonic firing and, as a result, distance-dependent dendritic attenuation remains consistent across different firing modes. Therefore, unlike LTS-associated global electrical and calcium signals, the spatial influence of bAP signaling in TC and TRN neurons is more restricted, with potentially important behavioral-state-dependent consequences for synaptic integration and plasticity in thalamic neurons. SIGNIFICANCE STATEMENT In most neurons, action potentials (APs) initiate in the axosomatic region and propagate into the dendritic tree to provide a retrograde signal that conveys information about the level of cellular output to the locations that receive most input: the dendrites. In thalamocortical and thalamic reticular nucleus neurons, the site of AP generation and the true extent of backpropagation remain unknown. Using patch-clamp recordings, this study measures dendritic propagation of APs directly in these neurons. In either cell type, high-frequency low-threshold spike burst or lower-frequency tonic APs undergo substantial voltage attenuation as they spread into the dendritic tree. Therefore, backpropagating spikes in these cells can only influence signaling in the proximal part of the dendritic tree. Copyright © 2017 Connelly et al.

Large variability in synaptic N-methyl-D-aspartate receptor density on interneurons and a comparison with pyramidal-cell spines in the rat hippocampus.

PubMed

Nyíri, G; Stephenson, F A; Freund, T F; Somogyi, P

2003-01-01

Pyramidal cells receive input from several types of GABA-releasing interneurons and innervate them reciprocally. Glutamatergic activation of interneurons involves both alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) type glutamate receptors expressed in type I synapses, mostly on their dendritic shafts. On average, the synaptic AMPA receptor content is several times higher on interneurons than in the spines of pyramidal cells. To compare the NMDA receptor content of synapses, we used a quantitative postembedding immunogold technique on serial electron microscopic sections, and analysed the synapses on interneuron dendrites and pyramidal cell spines in the CA1 area. Because all NMDA receptors contain the obligatory NR1 subunit, receptor localisation was carried out using antibodies recognising all splice variants of the NR1 subunit. Four populations of synapse were examined: i). on spines of pyramidal cells in stratum (str.) radiatum and str. oriens; ii). on parvalbumin-positive interneuronal dendritic shafts in str. radiatum; iii). on randomly found dendritic shafts in str. oriens and iv). on somatostatin-positive interneuronal dendritic shafts and somata in str. oriens. On average, the size of the synapses on spines was about half of those on interneurons. The four populations of synapse significantly differed in labelling for the NR1 subunit. The median density of NR1 subunit labelling was highest on pyramidal cell spines. It was lowest in the synapses on parvalbumin-positive dendrites in str. radiatum, where more than half of these synapses were immunonegative. In str. oriens, synapses on interneurons had a high variability of receptor content; some dendrites were similar to those in str. radiatum, including the proximal synapses of somatostatin-positive cells, whereas others had immunoreactivity for the NR1 subunit similar to or higher than synapses on pyramidal cell spines. These results show that synaptic NMDA receptor density differs between pyramidal cells and interneurons. Some interneurons may have a high NMDA receptor content, whereas others, like some parvalbumin-expressing cells, a particularly low synaptic NMDA receptor content. Consequently, fast glutamatergic activation of interneurons is expected to show cell type-specific time course and state-dependent dynamics.

Early increase and late decrease of purkinje cell dendritic spine density in prion-infected organotypic mouse cerebellar cultures.

PubMed

Campeau, Jody L; Wu, Gengshu; Bell, John R; Rasmussen, Jay; Sim, Valerie L

2013-01-01

Prion diseases are infectious neurodegenerative diseases associated with the accumulation of protease-resistant prion protein, neuronal loss, spongiform change and astrogliosis. In the mouse model, the loss of dendritic spines is one of the earliest pathological changes observed in vivo, occurring 4-5 weeks after the first detection of protease-resistant prion protein in the brain. While there are cell culture models of prion infection, most do not recapitulate the neuropathology seen in vivo. Only the recently developed prion organotypic slice culture assay has been reported to undergo neuronal loss and the development of some aspects of prion pathology, namely small vacuolar degeneration and tubulovesicular bodies. Given the rapid replication of prions in this system, with protease-resistant prion protein detectable by 21 days, we investigated whether the dendritic spine loss and altered dendritic morphology seen in prion disease might also develop within the lifetime of this culture system. Indeed, six weeks after first detection of protease-resistant prion protein in tga20 mouse cerebellar slice cultures infected with RML prion strain, we found a statistically significant loss of Purkinje cell dendritic spines and altered dendritic morphology in infected cultures, analogous to that seen in vivo. In addition, we found a transient but statistically significant increase in Purkinje cell dendritic spine density during infection, at the time when protease-resistant prion protein was first detectable in culture. Our findings support the use of this slice culture system as one which recapitulates prion disease pathology and one which may facilitate study of the earliest stages of prion disease pathogenesis.

High-resolution immunogold localization of AMPA type glutamate receptor subunits at synaptic and non-synaptic sites in rat hippocampus.

PubMed

Baude, A; Nusser, Z; Molnár, E; McIlhinney, R A; Somogyi, P

1995-12-01

The cellular and subcellular localization of the GluRA, GluRB/C and GluRD subunits of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) type glutamate receptor was determined in the rat hippocampus using polyclonal antipeptide antibodies in immunoperoxidase and immunogold procedures. For the localization of the GluRD subunit a new polyclonal antiserum was developed using the C-terminal sequence of the protein (residues 869-881), conjugated to carrier protein and absorbed to colloidal gold for immunization. The purified antibodies immunoprecipitated about 25% of 3[H]AMPA binding activity from the hippocampus, cerebellum or whole brain, but very little from neocortex. These antibodies did not precipitate a significant amount of 3[H]kainate binding activity. The antibodies also recognize the GluRD subunit, but not the other AMPA receptor subunits, when expressed in transfected COS-7 cells and only when permeabilized with detergent, indicating an intracellular epitope. All subunits were enriched in the neuropil of the dendritic layers of the hippocampus and in the molecular layer of the dentate gyrus. The cellular distribution of the GluRD subunit was studied more extensively. The strata radiatum, oriens and the dentate molecular layer were more strongly immunoreactive than the stratum lacunosum moleculare, the stratum lucidum and the hilus. However, in the stratum lucidum of the CA3 area and in the hilus the weakly reacting dendrites were surrounded by immunopositive rosettes, shown in subsequent electron microscopic studies to correspond to complex dendritic spines. In the stratum radiatum, the weakly reacting apical dendrites contrasted with the surrounding intensely stained neuropil. The cell bodies of pyramidal and granule cells were moderately reactive. Some non-principal cells and their dendrites in the pyramidal cell layer and in the alveus also reacted very strongly for the GluRD subunit. At the subcellular level, silver intensified immunogold particles for the GluRA, GluRB/C and GluRD subunits were present at type 1 synaptic membrane specializations on dendritic spines of pyramidal cells throughout all layers of the CA1 and CA3 areas. The most densely labelled synapses tended to be on the largest spines and many smaller spines remained unlabelled. Immunoparticle density at type 1 synapses on dendritic shafts of some non-principal cells was consistently higher than at labelled synapses of dendritic spines of pyramidal cells. Synapses established between dendritic spines and mossy fibre terminals, were immunoreactive for all studied subunits in stratum lucidum of the CA3 area. The postembedding immunogold method revealed that the AMPA type receptors are concentrated within the main body of the anatomically defined type 1 (asymmetrical) synaptic junction. Often only a part of the membrane specialization showed clustered immunoparticles. There was a sharp decrease in immunoreactive receptor density at the edge of the synaptic specialization. Immunolabelling was consistently demonstrated at extrasynaptic sites on dendrites, dendritic spines and somata. The results demonstrate that the GluRA, B/C and D subunits of the AMPA type glutamate receptor are present in many of the glutamatergic synapses formed by the entorhinal, CA3 pyramidal and mossy fibre terminals. Some interneurons have a higher density of AMPA type receptors in their asymmetrical afferent synapses than pyramidal cells. This may contribute to a lower activation threshold of interneurons as compared to principal cells by the same afferents in the hippocampal formation.

Rebamipide induces dendritic cell recruitment to N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-exposed rat gastric mucosa based on IL-1β upregulation.

PubMed

Yamamichi, Nobutake; Oka, Masashi; Inada, Ken-ichi; Konno-Shimizu, Maki; Kageyama-Yahara, Natsuko; Tamai, Hideyuki; Kato, Jun; Fujishiro, Mitsuhiro; Kodashima, Shinya; Niimi, Keiko; Ono, Satoshi; Tsutsumi, Yutaka; Ichinose, Masao; Koike, Kazuhiko

2012-07-20

Rebamipide is usually used for mucosal protection, healing of gastric ulcers, treatment of gastritis, etc., but its effects on gastric malignancy have not been elucidated. Using Lewis and Buffalo rat strains treated with peroral administration of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), we evaluated the effect of rebamipide on the induction of tumor-suppressive dendritic cells, which are known to be heterogeneous antigen-presenting cells of bone marrow origin and are critical for the initiation of primary T-cell responses. Using CD68 as a marker for dendritic cells, the stomach pyloric mucosae of Lewis and Buffalo rats were immunohistochemically analyzed in the presence or absence of rebamipide and MNNG. After a 14-day treatment of rebamipide alone, no significant change in number of CD68-expressing cells was detected in either rat strain. However, after concurrent exposure to MNNG for 14 days, treatment with rebamipide slightly increased CD68-positive cells in the Lewis strain, and significantly increased them in the Buffalo strain. Analysis of two chemotactic factors of dendritic cells, IL-1β and TNF-α, in the gastric cancer cells showed that expression of IL-1β, but not TNF-α, was induced by rebamipide in a dose-dependent manner. A luciferase promoter assay using gastric SH-10-TC cells demonstrated that an element mediating rebamipide action exists in the IL-1β gene promoter region. In conclusion, rebamipide has potential tumor-suppressive effects on gastric tumorigenesis via the recruitment of dendritic cells, based on the upregulation of the IL-1β gene in gastric epithelial cells. Copyright © 2012 Elsevier Inc. All rights reserved.

Passive dendrites enable single neurons to compute linearly non-separable functions.

PubMed

Cazé, Romain Daniel; Humphries, Mark; Gutkin, Boris

2013-01-01

Local supra-linear summation of excitatory inputs occurring in pyramidal cell dendrites, the so-called dendritic spikes, results in independent spiking dendritic sub-units, which turn pyramidal neurons into two-layer neural networks capable of computing linearly non-separable functions, such as the exclusive OR. Other neuron classes, such as interneurons, may possess only a few independent dendritic sub-units, or only passive dendrites where input summation is purely sub-linear, and where dendritic sub-units are only saturating. To determine if such neurons can also compute linearly non-separable functions, we enumerate, for a given parameter range, the Boolean functions implementable by a binary neuron model with a linear sub-unit and either a single spiking or a saturating dendritic sub-unit. We then analytically generalize these numerical results to an arbitrary number of non-linear sub-units. First, we show that a single non-linear dendritic sub-unit, in addition to the somatic non-linearity, is sufficient to compute linearly non-separable functions. Second, we analytically prove that, with a sufficient number of saturating dendritic sub-units, a neuron can compute all functions computable with purely excitatory inputs. Third, we show that these linearly non-separable functions can be implemented with at least two strategies: one where a dendritic sub-unit is sufficient to trigger a somatic spike; another where somatic spiking requires the cooperation of multiple dendritic sub-units. We formally prove that implementing the latter architecture is possible with both types of dendritic sub-units whereas the former is only possible with spiking dendrites. Finally, we show how linearly non-separable functions can be computed by a generic two-compartment biophysical model and a realistic neuron model of the cerebellar stellate cell interneuron. Taken together our results demonstrate that passive dendrites are sufficient to enable neurons to compute linearly non-separable functions.

Passive Dendrites Enable Single Neurons to Compute Linearly Non-separable Functions

PubMed Central

Cazé, Romain Daniel; Humphries, Mark; Gutkin, Boris

2013-01-01

Local supra-linear summation of excitatory inputs occurring in pyramidal cell dendrites, the so-called dendritic spikes, results in independent spiking dendritic sub-units, which turn pyramidal neurons into two-layer neural networks capable of computing linearly non-separable functions, such as the exclusive OR. Other neuron classes, such as interneurons, may possess only a few independent dendritic sub-units, or only passive dendrites where input summation is purely sub-linear, and where dendritic sub-units are only saturating. To determine if such neurons can also compute linearly non-separable functions, we enumerate, for a given parameter range, the Boolean functions implementable by a binary neuron model with a linear sub-unit and either a single spiking or a saturating dendritic sub-unit. We then analytically generalize these numerical results to an arbitrary number of non-linear sub-units. First, we show that a single non-linear dendritic sub-unit, in addition to the somatic non-linearity, is sufficient to compute linearly non-separable functions. Second, we analytically prove that, with a sufficient number of saturating dendritic sub-units, a neuron can compute all functions computable with purely excitatory inputs. Third, we show that these linearly non-separable functions can be implemented with at least two strategies: one where a dendritic sub-unit is sufficient to trigger a somatic spike; another where somatic spiking requires the cooperation of multiple dendritic sub-units. We formally prove that implementing the latter architecture is possible with both types of dendritic sub-units whereas the former is only possible with spiking dendrites. Finally, we show how linearly non-separable functions can be computed by a generic two-compartment biophysical model and a realistic neuron model of the cerebellar stellate cell interneuron. Taken together our results demonstrate that passive dendrites are sufficient to enable neurons to compute linearly non-separable functions. PMID:23468600

Dendritic Immunotherapy Improvement for an Optimal Control Murine Model

PubMed Central

Chimal-Eguía, J. C.; Castillo-Montiel, E.

2017-01-01

Therapeutic protocols in immunotherapy are usually proposed following the intuition and experience of the therapist. In order to deduce such protocols mathematical modeling, optimal control and simulations are used instead of the therapist's experience. Clinical efficacy of dendritic cell (DC) vaccines to cancer treatment is still unclear, since dendritic cells face several obstacles in the host environment, such as immunosuppression and poor transference to the lymph nodes reducing the vaccine effect. In view of that, we have created a mathematical murine model to measure the effects of dendritic cell injections admitting such obstacles. In addition, the model considers a therapy given by bolus injections of small duration as opposed to a continual dose. Doses timing defines the therapeutic protocols, which in turn are improved to minimize the tumor mass by an optimal control algorithm. We intend to supplement therapist's experience and intuition in the protocol's implementation. Experimental results made on mice infected with melanoma with and without therapy agree with the model. It is shown that the dendritic cells' percentage that manages to reach the lymph nodes has a crucial impact on the therapy outcome. This suggests that efforts in finding better methods to deliver DC vaccines should be pursued. PMID:28912828

The fungal quorum-sensing molecule farnesol activates innate immune cells but suppresses cellular adaptive immunity.

PubMed

Leonhardt, Ines; Spielberg, Steffi; Weber, Michael; Albrecht-Eckardt, Daniela; Bläss, Markus; Claus, Ralf; Barz, Dagmar; Scherlach, Kirstin; Hertweck, Christian; Löffler, Jürgen; Hünniger, Kerstin; Kurzai, Oliver

2015-03-17

Farnesol, produced by the polymorphic fungus Candida albicans, is the first quorum-sensing molecule discovered in eukaryotes. Its main function is control of C. albicans filamentation, a process closely linked to pathogenesis. In this study, we analyzed the effects of farnesol on innate immune cells known to be important for fungal clearance and protective immunity. Farnesol enhanced the expression of activation markers on monocytes (CD86 and HLA-DR) and neutrophils (CD66b and CD11b) and promoted oxidative burst and the release of proinflammatory cytokines (tumor necrosis factor alpha [TNF-α] and macrophage inflammatory protein 1 alpha [MIP-1α]). However, this activation did not result in enhanced fungal uptake or killing. Furthermore, the differentiation of monocytes to immature dendritic cells (iDC) was significantly affected by farnesol. Several markers important for maturation and antigen presentation like CD1a, CD83, CD86, and CD80 were significantly reduced in the presence of farnesol. Furthermore, farnesol modulated migrational behavior and cytokine release and impaired the ability of DC to induce T cell proliferation. Of major importance was the absence of interleukin 12 (IL-12) induction in iDC generated in the presence of farnesol. Transcriptome analyses revealed a farnesol-induced shift in effector molecule expression and a down-regulation of the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor during monocytes to iDC differentiation. Taken together, our data unveil the ability of farnesol to act as a virulence factor of C. albicans by influencing innate immune cells to promote inflammation and mitigating the Th1 response, which is essential for fungal clearance. Farnesol is a quorum-sensing molecule which controls morphological plasticity of the pathogenic yeast Candida albicans. As such, it is a major mediator of intraspecies communication. Here, we investigated the impact of farnesol on human innate immune cells known to be important for fungal clearance and protective immunity. We show that farnesol is able to enhance inflammation by inducing activation of neutrophils and monocytes. At the same time, farnesol impairs differentiation of monocytes into immature dendritic cells (iDC) by modulating surface phenotype, cytokine release and migrational behavior. Consequently, iDC generated in the presence of farnesol are unable to induce proper T cell responses and fail to secrete Th1 promoting interleukin 12 (IL-12). As farnesol induced down-regulation of the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor, desensitization to GM-CSF could potentially explain transcriptional reprofiling of iDC effector molecules. Taken together, our data show that farnesol can also mediate Candida-host communication and is able to act as a virulence factor. Copyright © 2015 Leonhardt et al.

Two-Photon Na+ Imaging Reports Somatically Evoked Action Potentials in Rat Olfactory Bulb Mitral and Granule Cell Neurites.

PubMed

Ona-Jodar, Tiffany; Gerkau, Niklas J; Sara Aghvami, S; Rose, Christine R; Egger, Veronica

2017-01-01

Dendrodendritic synaptic interactions are a hallmark of neuronal processing in the vertebrate olfactory bulb. Many classes of olfactory bulb neurons including the principal mitral cells (MCs) and the axonless granule cells (GCs) dispose of highly efficient propagation of action potentials (AP) within their dendrites, from where they can release transmitter onto each other. So far, backpropagation in GC dendrites has been investigated indirectly via Ca 2+ imaging. Here, we used two-photon Na + imaging to directly report opening of voltage-gated sodium channels due to AP propagation in both cell types. To this end, neurons in acute slices from juvenile rat bulbs were filled with 1 mM SBFI via whole-cell patch-clamp. Calibration of SBFI signals revealed that a change in fluorescence Δ F / F by 10% corresponded to a Δ[Na + ] i of ∼22 mM. We then imaged proximal axon segments of MCs during somatically evoked APs (sAP). While single sAPs were detectable in ∼50% of axons, trains of 20 sAPs at 50 Hz always resulted in substantial Δ F / F of ∼15% (∼33 mM Δ[Na + ] i ). Δ F / F was significantly larger for 80 Hz vs. 50 Hz trains, and decayed with half-durations τ 1/2 ∼0.6 s for both frequencies. In MC lateral dendrites, AP trains yielded small Δ F / F of ∼3% (∼7 mM Δ[Na + ] i ). In GC apical dendrites and adjacent spines, single sAPs were not detectable. Trains resulted in an average dendritic Δ F / F of 7% (16 mM Δ[Na + ] i ) with τ 1/2 ∼1 s, similar for 50 and 80 Hz. Na + transients were indistinguishable between large GC spines and their adjacent dendrites. Cell-wise analysis revealed two classes of GCs with the first showing a decrease in Δ F / F along the dendrite with distance from the soma and the second an increase. These classes clustered with morphological parameters. Simulations of Δ[Na + ] i replicated these behaviors via negative and positive gradients in Na + current density, assuming faithful AP backpropagation. Such specializations of dendritic excitability might confer specific temporal processing capabilities to bulbar principal cell-GC subnetworks. In conclusion, we show that Na + imaging provides a valuable tool for characterizing AP invasion of MC axons and GC dendrites and spines.

Two-Photon Na+ Imaging Reports Somatically Evoked Action Potentials in Rat Olfactory Bulb Mitral and Granule Cell Neurites

PubMed Central

Ona-Jodar, Tiffany; Gerkau, Niklas J.; Sara Aghvami, S.; Rose, Christine R.; Egger, Veronica

2017-01-01

Dendrodendritic synaptic interactions are a hallmark of neuronal processing in the vertebrate olfactory bulb. Many classes of olfactory bulb neurons including the principal mitral cells (MCs) and the axonless granule cells (GCs) dispose of highly efficient propagation of action potentials (AP) within their dendrites, from where they can release transmitter onto each other. So far, backpropagation in GC dendrites has been investigated indirectly via Ca2+ imaging. Here, we used two-photon Na+ imaging to directly report opening of voltage-gated sodium channels due to AP propagation in both cell types. To this end, neurons in acute slices from juvenile rat bulbs were filled with 1 mM SBFI via whole-cell patch-clamp. Calibration of SBFI signals revealed that a change in fluorescence ΔF/F by 10% corresponded to a Δ[Na+]i of ∼22 mM. We then imaged proximal axon segments of MCs during somatically evoked APs (sAP). While single sAPs were detectable in ∼50% of axons, trains of 20 sAPs at 50 Hz always resulted in substantial ΔF/F of ∼15% (∼33 mM Δ[Na+]i). ΔF/F was significantly larger for 80 Hz vs. 50 Hz trains, and decayed with half-durations τ1/2 ∼0.6 s for both frequencies. In MC lateral dendrites, AP trains yielded small ΔF/F of ∼3% (∼7 mM Δ[Na+]i). In GC apical dendrites and adjacent spines, single sAPs were not detectable. Trains resulted in an average dendritic ΔF/F of 7% (16 mM Δ[Na+]i) with τ1/2 ∼1 s, similar for 50 and 80 Hz. Na+ transients were indistinguishable between large GC spines and their adjacent dendrites. Cell-wise analysis revealed two classes of GCs with the first showing a decrease in ΔF/F along the dendrite with distance from the soma and the second an increase. These classes clustered with morphological parameters. Simulations of Δ[Na+]i replicated these behaviors via negative and positive gradients in Na+ current density, assuming faithful AP backpropagation. Such specializations of dendritic excitability might confer specific temporal processing capabilities to bulbar principal cell-GC subnetworks. In conclusion, we show that Na+ imaging provides a valuable tool for characterizing AP invasion of MC axons and GC dendrites and spines. PMID:28293175

Obesity-Induced Metabolic Stress Leads to Biased Effector Memory CD4+ T Cell Differentiation via PI3K p110δ-Akt-Mediated Signals.

PubMed

Mauro, Claudio; Smith, Joanne; Cucchi, Danilo; Coe, David; Fu, Hongmei; Bonacina, Fabrizia; Baragetti, Andrea; Cermenati, Gaia; Caruso, Donatella; Mitro, Nico; Catapano, Alberico L; Ammirati, Enrico; Longhi, Maria P; Okkenhaug, Klaus; Norata, Giuseppe D; Marelli-Berg, Federica M

2017-03-07

Low-grade systemic inflammation associated to obesity leads to cardiovascular complications, caused partly by infiltration of adipose and vascular tissue by effector T cells. The signals leading to T cell differentiation and tissue infiltration during obesity are poorly understood. We tested whether saturated fatty acid-induced metabolic stress affects differentiation and trafficking patterns of CD4 + T cells. Memory CD4 + T cells primed in high-fat diet-fed donors preferentially migrated to non-lymphoid, inflammatory sites, independent of the metabolic status of the hosts. This was due to biased CD4 + T cell differentiation into CD44 hi -CCR7 lo -CD62L lo -CXCR3 + -LFA1 + effector memory-like T cells upon priming in high-fat diet-fed animals. Similar phenotype was observed in obese subjects in a cohort of free-living people. This developmental bias was independent of any crosstalk between CD4 + T cells and dendritic cells and was mediated via direct exposure of CD4 + T cells to palmitate, leading to increased activation of a PI3K p110δ-Akt-dependent pathway upon priming. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Dendrites of dentate gyrus granule cells contribute to pattern separation by controlling sparsity

PubMed Central

Chavlis, Spyridon; Petrantonakis, Panagiotis C.

2016-01-01

ABSTRACT The hippocampus plays a key role in pattern separation, the process of transforming similar incoming information to highly dissimilar, nonverlapping representations. Sparse firing granule cells (GCs) in the dentate gyrus (DG) have been proposed to undertake this computation, but little is known about which of their properties influence pattern separation. Dendritic atrophy has been reported in diseases associated with pattern separation deficits, suggesting a possible role for dendrites in this phenomenon. To investigate whether and how the dendrites of GCs contribute to pattern separation, we build a simplified, biologically relevant, computational model of the DG. Our model suggests that the presence of GC dendrites is associated with high pattern separation efficiency while their atrophy leads to increased excitability and performance impairments. These impairments can be rescued by restoring GC sparsity to control levels through various manipulations. We predict that dendrites contribute to pattern separation as a mechanism for controlling sparsity. © 2016 The Authors Hippocampus Published by Wiley Periodicals, Inc. PMID:27784124

Dendritic nonlinearities are tuned for efficient spike-based computations in cortical circuits

PubMed Central

Ujfalussy, Balázs B; Makara, Judit K; Branco, Tiago; Lengyel, Máté

2015-01-01

Cortical neurons integrate thousands of synaptic inputs in their dendrites in highly nonlinear ways. It is unknown how these dendritic nonlinearities in individual cells contribute to computations at the level of neural circuits. Here, we show that dendritic nonlinearities are critical for the efficient integration of synaptic inputs in circuits performing analog computations with spiking neurons. We developed a theory that formalizes how a neuron's dendritic nonlinearity that is optimal for integrating synaptic inputs depends on the statistics of its presynaptic activity patterns. Based on their in vivo preynaptic population statistics (firing rates, membrane potential fluctuations, and correlations due to ensemble dynamics), our theory accurately predicted the responses of two different types of cortical pyramidal cells to patterned stimulation by two-photon glutamate uncaging. These results reveal a new computational principle underlying dendritic integration in cortical neurons by suggesting a functional link between cellular and systems--level properties of cortical circuits. DOI: http://dx.doi.org/10.7554/eLife.10056.001 PMID:26705334

Meigo governs dendrite targeting specificity by modulating Ephrin level and N-glycosylation

PubMed Central

Sekine, Sayaka U; Haraguchi, Shuka; Chao, Kinhong; Kato, Tomoko; Luo, Liqun; Miura, Masayuki; Chihara, Takahiro

2016-01-01

Neural circuit assembly requires precise dendrite and axon targeting. We identified an evolutionarily conserved endoplasmic reticulum (ER) protein, Meigo, from a mosaic genetic screen in Drosophila melanogaster. Meigo was cell-autonomously required in olfactory receptor neurons and projection neurons to target their axons and dendrites to the lateral antennal lobe and to refine projection neuron dendrites into individual glomeruli. Loss of Meigo induced an unfolded protein response and reduced the amount of neuronal cell surface proteins, including Ephrin. Ephrin overexpression specifically suppressed the projection neuron dendrite refinement defect present in meigo mutant flies, and ephrin knockdown caused a similar projection neuron dendrite refinement defect. Meigo positively regulated the level of Ephrin N-glycosylation, which was required for its optimal function in vivo. Thus, Meigo, an ER-resident protein, governs neuronal targeting specificity by regulating ER folding capacity and protein N-glycosylation. Furthermore, Ephrin appears to be an important substrate that mediates Meigo’s function in refinement of glomerular targeting. PMID:23624514

Direct antigen presentation and gap junction mediated cross-presentation during apoptosis.

PubMed

Pang, Baoxu; Neijssen, Joost; Qiao, Xiaohang; Janssen, Lennert; Janssen, Hans; Lippuner, Christoph; Neefjes, Jacques

2009-07-15

MHC class I molecules present peptides from endogenous proteins. Ags can also be presented when derived from extracellular sources in the form of apoptotic bodies. Cross-presentation of such Ags by dendritic cells is required for proper CTL responses. The fate of Ags in cells initiated for apoptosis is unclear as is the mechanism of apoptosis-derived Ag transfer into dendritic cells. Here we show that novel Ags can be generated by caspases and be presented by MHC class I molecules of apoptotic cells. Since gap junctions function until apoptotic cells remodel to form apoptotic bodies, transfer and cross-presentation of apoptotic peptides by neighboring and dendritic cells occurs. We thus define a novel phase in classical Ag presentation and cross-presentation by MHC class I molecules: presentation of Ags created by caspase activities in cells in apoptosis.

Dendritic cells in cancer immunotherapy

NASA Astrophysics Data System (ADS)

Le Gall, Camille M.; Weiden, Jorieke; Eggermont, Loek J.; Figdor, Carl G.

2018-06-01

Camille M. Le Gall, Jorieke Weiden, Loek J. Eggermont and Carl G. Figdor provide an overview of immunotherapeutics for cancer treatment that harness dendritic cells, their challenges in clinical use, and approaches employed to enhance their recruitment and activation to promote effective anti-tumour immunity.

'Educated' dendritic cells act as messengers from memory to naive T helper cells.

PubMed

Alpan, Oral; Bachelder, Eric; Isil, Eda; Arnheiter, Heinz; Matzinger, Polly

2004-06-01

Ingested antigens lead to the generation of effector T cells that secrete interleukin 4 (IL-4) rather than interferon-gamma (IFN-gamma) and are capable of influencing naive T cells in their immediate environment to do the same. Using chimeric mice generated by aggregation of two genotypically different embryos, we found that the conversion of a naive T cell occurs only if it can interact with the same antigen-presenting cell, although not necessarily the same antigen, as the effector T cell. Using a two-step culture system in vitro, we found that antigen-presenting dendritic cells can act as 'temporal bridges' to relay information from orally immunized memory CD4 T cells to naive CD4 T cells. The orally immunized T cells use IL-4 and IL-10 (but not CD40 ligand) to 'educate' dendritic cells, which in turn induce naive T cells to produce the same cytokines as those produced by the orally immunized memory T cells.

Transcriptional Classification and Functional Characterization of Human Airway Macrophage and Dendritic Cell Subsets

PubMed Central

Patel, Vineet I.; Booth, J. Leland; Duggan, Elizabeth S.; Cate, Steven; White, Vicky L.; Hutchings, David; Kovats, Susan; Burian, Dennis M.; Dozmorov, Mikhail; Metcalf, Jordan P.

2016-01-01

The respiratory system is a complex network of many cell types, including subsets of macrophages and dendritic cells that work together to maintain steady-state respiration. Due to limitations in acquiring cells from healthy human lung, these subsets remain poorly characterized transcriptionally and phenotypically. We set out to systematically identify these subsets in human airways by developing a schema of isolating large numbers of cells by whole lung bronchoalveolar lavage. Six subsets of phagocytic antigen presenting (HLA-DR+) cells were consistently observed. Aside from alveolar macrophages, subsets of Langerin+, BDCA1− CD14+, BDCA1+ CD14+, BDCA1+ CD14−, and BDCA1− CD14− cells were identified. These subsets varied in their ability to internalize Escherichia coli, Staphylococcus aureus, and Bacillus anthracis particles. All subsets were more efficient at internalizing S. aureus and B. anthracis compared to E. coli. Alveolar macrophages and CD14+ cells were overall more efficient at particle internalization compared to the four other populations. Subsets were further separated into two groups based on their inherent capacities to upregulate surface CD83, CD86, and CCR7 expression levels. Whole genome transcriptional profiling revealed a clade of “true dendritic cells” consisting of Langerin+, BDCA1+ CD14+, and BDCA1+ CD14− cells. The dendritic cell clade was distinct from a macrophage/monocyte clade, as supported by higher mRNA expression levels of several dendritic cell-associated genes, including CD1, FLT3, CX3CR1, and CCR6. Each clade, and each member of both clades, were discerned by specific upregulated genes, which can serve as markers for future studies in healthy and diseased states. PMID:28031342

Amplitude Normalization of Dendritic EPSPs at the Soma of Binaural Coincidence Detector Neurons of the Medial Superior Olive

PubMed Central

Winters, Bradley D.; Jin, Shan-Xue; Ledford, Kenneth R.

2017-01-01

The principal neurons of the medial superior olive (MSO) encode cues for horizontal sound localization through comparisons of the relative timing of EPSPs. To understand how the timing and amplitude of EPSPs are maintained during propagation in the dendrites, we made dendritic and somatic whole-cell recordings from MSO principal neurons in brain slices from Mongolian gerbils. In somatic recordings, EPSP amplitudes were largely uniform following minimal stimulation of excitatory synapses at visualized locations along the dendrites. Similar results were obtained when excitatory synaptic transmission was eliminated in a low calcium solution and then restored at specific dendritic sites by pairing input stimulation and focal application of a higher calcium solution. We performed dual dendritic and somatic whole-cell recordings to measure spontaneous EPSPs using a dual-channel template-matching algorithm to separate out those events initiated at or distal to the dendritic recording location. Local dendritic spontaneous EPSP amplitudes increased sharply in the dendrite with distance from the soma (length constant, 53.6 μm), but their attenuation during propagation resulted in a uniform amplitude of ∼0.2 mV at the soma. The amplitude gradient of dendritic EPSPs was also apparent in responses to injections of identical simulated excitatory synaptic currents in the dendrites. Compartmental models support the view that these results extensively reflect the influence of dendritic cable properties. With relatively few excitatory axons innervating MSO neurons, the normalization of dendritic EPSPs at the soma would increase the importance of input timing versus location during the processing of interaural time difference cues in vivo. SIGNIFICANCE STATEMENT The neurons of the medial superior olive analyze cues for sound localization by detecting the coincidence of binaural excitatory synaptic inputs distributed along the dendrites. Previous studies have shown that dendritic voltages undergo severe attenuation as they propagate to the soma, potentially reducing the influence of distal inputs. However, using dendritic and somatic patch recordings, we found that dendritic EPSP amplitude increased with distance from the soma, compensating for dendritic attenuation and normalizing EPSP amplitude at the soma. Much of this normalization reflected the influence of dendritic morphology. As different combinations of presynaptic axons may be active during consecutive cycles of sound stimuli, somatic EPSP normalization renders spike initiation more sensitive to synapse timing than dendritic location. PMID:28213442

Turtle Functions Downstream of Cut in Differentially Regulating Class Specific Dendrite Morphogenesis in Drosophila

PubMed Central

Sulkowski, Mikolaj J.; Iyer, Srividya Chandramouli; Kurosawa, Mathieu S.; Iyer, Eswar Prasad R.; Cox, Daniel N.

2011-01-01

Background Dendritic morphology largely determines patterns of synaptic connectivity and electrochemical properties of a neuron. Neurons display a myriad diversity of dendritic geometries which serve as a basis for functional classification. Several types of molecules have recently been identified which regulate dendrite morphology by acting at the levels of transcriptional regulation, direct interactions with the cytoskeleton and organelles, and cell surface interactions. Although there has been substantial progress in understanding the molecular mechanisms of dendrite morphogenesis, the specification of class-specific dendritic arbors remains largely unexplained. Furthermore, the presence of numerous regulators suggests that they must work in concert. However, presently, few genetic pathways regulating dendrite development have been defined. Methodology/Principal Findings The Drosophila gene turtle belongs to an evolutionarily conserved class of immunoglobulin superfamily members found in the nervous systems of diverse organisms. We demonstrate that Turtle is differentially expressed in Drosophila da neurons. Moreover, MARCM analyses reveal Turtle acts cell autonomously to exert class specific effects on dendritic growth and/or branching in da neuron subclasses. Using transgenic overexpression of different Turtle isoforms, we find context-dependent, isoform-specific effects on mediating dendritic branching in class II, III and IV da neurons. Finally, we demonstrate via chromatin immunoprecipitation, qPCR, and immunohistochemistry analyses that Turtle expression is positively regulated by the Cut homeodomain transcription factor and via genetic interaction studies that Turtle is downstream effector of Cut-mediated regulation of da neuron dendrite morphology. Conclusions/Significance Our findings reveal that Turtle proteins differentially regulate the acquisition of class-specific dendrite morphologies. In addition, we have established a transcriptional regulatory interaction between Cut and Turtle, representing a novel pathway for mediating class specific dendrite development. PMID:21811639

Pcdh19 Loss-of-Function Increases Neuronal Migration In Vitro but is Dispensable for Brain Development in Mice

PubMed Central

Pederick, Daniel T.; Homan, Claire C.; Jaehne, Emily J.; Piltz, Sandra G.; Haines, Bryan P.; Baune, Bernhard T.; Jolly, Lachlan A.; Hughes, James N.; Gecz, Jozef; Thomas, Paul Q.

2016-01-01

Protocadherin 19 (Pcdh19) is an X-linked gene belonging to the protocadherin superfamily, whose members are predominantly expressed in the central nervous system and have been implicated in cell-cell adhesion, axon guidance and dendrite self-avoidance. Heterozygous loss-of-function mutations in humans result in the childhood epilepsy disorder PCDH19 Girls Clustering Epilepsy (PCDH19 GCE) indicating that PCDH19 is required for brain development. However, understanding PCDH19 function in vivo has proven challenging and has not been studied in mammalian models. Here, we validate a murine Pcdh19 null allele in which a β-Geo reporter cassette is expressed under the control of the endogenous promoter. Analysis of β-Geo reporter activity revealed widespread but restricted expression of PCDH19 in embryonic, postnatal and adult brains. No gross morphological defects were identified in Pcdh19+/β-Geo and Pcdh19Y/β-Geo brains and the location of Pcdh19 null cells was normal. However, in vitro migration assays revealed that the motility of Pcdh19 null neurons was significantly elevated, potentially contributing to pathogenesis in patients with PCDH19 mutations. Overall our initial characterization of Pcdh19+/β-Geo, Pcdh19β-Geo/β-Geo and Pcdh19Y/β-Geomice reveals that despite widespread expression of Pcdh19 in the CNS, and its role in human epilepsy, its function in mice is not essential for brain development. PMID:27240640

γ-Tocopherol supplementation of allergic female mice augments development of CD11c+CD11b+ dendritic cells in utero and allergic inflammation in neonates

PubMed Central

Abdala-Valencia, Hiam; Soveg, Frank

2016-01-01

γ-Tocopherol increases responses to allergen challenge in allergic adult mice, but it is not known whether γ-tocopherol regulates the development of allergic disease. Development of allergic disease often occurs early in life. In clinical studies and animal models, offspring of allergic mothers have increased responsiveness to allergen challenge. Therefore, we determined whether γ-tocopherol augments development of allergic responses in offspring of allergic female mice. Allergic female mice were supplemented with γ-tocopherol starting at mating. The pups from allergic mothers developed allergic lung responses, whereas pups from saline-treated mothers did not respond to allergen challenge. The γ-tocopherol supplementation of allergic female mice increased the numbers of eosinophils twofold in the pup bronchoalveolar lavage and lungs after allergen challenge. There was also about a twofold increase in pup lung CD11b+ subsets of CD11c+ dendritic cells and in numbers of these dendritic cells expressing the transcription factor IRF4. There was no change in several CD11b− dendritic cell subsets. Furthermore, maternal supplementation with γ-tocopherol increased the number of fetal liver CD11b+CD11c+ dendritic cells twofold in utero. In the pups, γ-tocopherol increased lung expression of the inflammatory mediators CCL11, amphiregulin, activin A, and IL-5. In conclusion, maternal supplementation with γ-tocopherol increased fetal development of subsets of dendritic cells that are critical for allergic responses and increased development of allergic responses in pups from allergic mothers. These results have implications for supplementation of allergic mothers with γ-tocopherol in prenatal vitamins. PMID:26801566

Distinct Dendritic Arborization and In Vivo Firing Patterns of Parvalbumin-Expressing Basket Cells in the Hippocampal Area CA3

PubMed Central

Tukker, John J.; Lasztóczi, Bálint; Katona, Linda; Roberts, J. David B.; Pissadaki, Eleftheria K.; Dalezios, Yannis; Márton, László; Zhang, Limei; Klausberger, Thomas; Somogyi, Peter

2015-01-01

Hippocampal CA3 area generates temporally structured network activity such as sharp waves and gamma and theta oscillations. Parvalbumin-expressing basket cells, making GABAergic synapses onto cell bodies and proximal dendrites of pyramidal cells, control pyramidal cell activity and participate in network oscillations in slice preparations, but their roles in vivo remain to be tested. We have recorded the spike timing of parvalbumin-expressing basket cells in areas CA2/3 of anesthetized rats in relation to CA3 putative pyramidal cell firing and activity locally and in area CA1. During theta oscillations, CA2/3 basket cells fired on the same phase as putative pyramidal cells, but, surprisingly, significantly later than downstream CA1 basket cells. This indicates a distinct modulation of CA3 and CA1 pyramidal cells by basket cells, which receive different inputs. We observed unexpectedly large dendritic arborization of CA2/3 basket cells in stratum lacunosum moleculare (33% of length, 29% surface, and 24% synaptic input from a total of ~35,000), different from the dendritic arborizations of CA1 basket cells. Area CA2/3 basket cells fired phase locked to both CA2/3 and CA1 gamma oscillations, and increased firing during CA1 sharp waves, thus supporting the role of CA3 networks in the generation of gamma oscillations and sharp waves. However, during ripples associated with sharp waves, firing of CA2/3 basket cells was phase locked only to local but not CA1 ripples, suggesting the independent generation of fast oscillations by basket cells in CA1 and CA2/3. The distinct spike timing of basket cells during oscillations in CA1 and CA2/3 suggests differences in synaptic inputs paralleled by differences in dendritic arborizations. PMID:23595740

Morphological Behavior of Printed Silver Electrodes with Protective Self-Assembled Monolayers for Electrochemical Migration.

PubMed

Sekine, Tomohito; Sato, Jun; Takeda, Yasunori; Kumaki, Daisuke; Tokito, Shizuo

2018-05-09

We evaluated the electrochemical behaviors and reliability of printed silver (Ag) electrodes prepared from nanoparticle inks with the use of protective self-assembled monolayers (SAMs) under electronic bias conditions. The printed Ag electrodes were fabricated by inkjet printing on a hydrophobic substrate. The SAMs, which acted as barriers to moisture, were prepared by immersing the substrate in a pentafluorobenzenethiol solution at ambient temperature (25 °C). We investigated the electrochemical migration phenomenon using the water drop method, and the results showed that the formation of dendrites connecting the cathode and the anode, which can affect the electrochemical reliability of an electric device, was suppressed in the presence of the SAMs. The time before short circuit occurred was found to depend on the spacing between the electrodes, i.e., 130 s, when the distance between the electrodes was 200 μm in the presence of an SAM. We demonstrated that Ag electrodes treated using the procedure described in this work suppress the occurrence of electrical short circuits caused by Ag dendrite formation and thus their electrochemical properties are substantially improved.

Electrochemical Migration of Fine-Pitch Nanopaste Ag Interconnects

NASA Astrophysics Data System (ADS)

Tsou, Chia-Hung; Liu, Kai-Ning; Lin, Heng-Tien; Ouyang, Fan-Yi

2016-12-01

With the development of intelligent electronic products, usage of fine-pitch interconnects has become mainstream in high performance electronic devices. Electrochemical migration (ECM) of interconnects would be a serious reliability problem under temperature, humidity and biased voltage environments. In this study, ECM behavior of nanopaste Ag interconnects with pitch size from 20 μm to 50 μm was evaluated by thermal humidity bias (THB) and water drop (WD) tests with deionized water through in situ leakage current-versus-time (CVT) curve. The results indicate that the failure time of ECM in fine-pitch samples occurs within few seconds under WD testing and it increases with increasing pitch size. The microstructure examination indicated that intensive dendrite formation of Ag through the whole interface was found to bridge the two electrodes. In the THB test, the CVT curve exhibited two stages, incubation and ramp-up; failure time of ECM was about 173.7 min. In addition, intensive dendrite formation was observed only at the protrusion of the Ag interconnects due to the concentration of the electric field at the protrusion of the Ag interconnects.

Reduced immune responses in chimeric mice engrafted with bone marrow cells from mice with airways inflammation.

PubMed

Scott, Naomi M; Ng, Royce L X; McGonigle, Terence A; Gorman, Shelley; Hart, Prue H

2015-11-01

During respiratory inflammation, it is generally assumed that dendritic cells differentiating from the bone marrow are immunogenic rather than immunoregulatory. Using chimeric mice, the outcomes of airways inflammation on bone marrow progenitor cells were studied. Immune responses were analyzed in chimeric mice engrafted for >16 weeks with bone marrow cells from mice with experimental allergic airways disease (EAAD). Responses to sensitization and challenge with the allergen causing inflammation in the bone marrow-donor mice were significantly reduced in the chimeric mice engrafted with bone marrow cells from mice with EAAD (EAAD-chimeric). Responses to intranasal LPS and topical fluorescein isothiocyanate (non-specific challenges) were significantly attenuated. Fewer activated dendritic cells from the airways and skin of the EAAD-chimeric mice could be tracked to the draining lymph nodes, and may contribute to the significantly reduced antigen/chemical-induced hypertrophy in the draining nodes, and the reduced immune responses to sensitizing allergens. Dendritic cells differentiating in vitro from the bone marrow of >16 weeks reconstituted EAAD-chimeric mice retained an ability to poorly prime immune responses when transferred into naïve mice. Dendritic cells developing from bone marrow progenitors during airways inflammation are altered such that daughter cells have reduced antigen priming capabilities.