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  1. Active dendrites enhance neuronal dynamic range.

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    Leonardo L Gollo

    2009-06-01

    Full Text Available Since the first experimental evidences of active conductances in dendrites, most neurons have been shown to exhibit dendritic excitability through the expression of a variety of voltage-gated ion channels. However, despite experimental and theoretical efforts undertaken in the past decades, the role of this excitability for some kind of dendritic computation has remained elusive. Here we show that, owing to very general properties of excitable media, the average output of a model of an active dendritic tree is a highly non-linear function of its afferent rate, attaining extremely large dynamic ranges (above 50 dB. Moreover, the model yields double-sigmoid response functions as experimentally observed in retinal ganglion cells. We claim that enhancement of dynamic range is the primary functional role of active dendritic conductances. We predict that neurons with larger dendritic trees should have larger dynamic range and that blocking of active conductances should lead to a decrease in dynamic range.

  2. Specific activation of dendritic cells enhances clearance of Bacillus anthracis following infection.

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    Thompson, Iain J T; Mann, Elizabeth R; Stokes, Margaret G; English, Nicholas R; Knight, Stella C; Williamson, Diane

    2014-01-01

    Dendritic cells are potent activators of the immune system and have a key role in linking innate and adaptive immune responses. In the current study we have used ex vivo pulsed bone marrow dendritic cells (BMDC) in a novel adoptive transfer strategy to protect against challenge with Bacillus anthracis, in a murine model. Pre-pulsing murine BMDC with either recombinant Protective Antigen (PA) or CpG significantly upregulated expression of the activation markers CD40, CD80, CD86 and MHC-II. Passive transfusion of mice with pulsed BMDC, concurrently with active immunisation with rPA in alum, significantly enhanced (pBMDC, demonstrated 100% survival following lethal B. anthracis challenge and had significantly enhanced (p<0.05) bacterial clearance within 2 days, compared with mice vaccinated with rPA and alum alone.

  3. Activation of the Inflammasome and Enhanced Migration of Microparticle-Stimulated Dendritic Cells to the Draining Lymph Node

    OpenAIRE

    Meraz, Ismail M.; Melendez, Brenda; Gu, Jianhua; Wong, Stephen T. C.; Liu, Xuewu; Andersson, Helen A.; Serda, Rita E.

    2012-01-01

    Porous silicon microparticles presenting pathogen-associated molecular patterns mimic pathogens, enhancing internalization of the microparticles and activation of antigen presenting dendritic cells. We demonstrate abundant uptake of microparticles bound by the TLR-4 ligands LPS and MPL by murine bone marrow-derived dendritic cells (BMDC). Labeled microparticles induce concentration-dependent production of IL-1β, with inhibition by the caspase inhibitor Z-VAD-FMK supporting activation of the N...

  4. Specific activation of dendritic cells enhances clearance of Bacillus anthracis following infection.

    Directory of Open Access Journals (Sweden)

    Iain J T Thompson

    Full Text Available Dendritic cells are potent activators of the immune system and have a key role in linking innate and adaptive immune responses. In the current study we have used ex vivo pulsed bone marrow dendritic cells (BMDC in a novel adoptive transfer strategy to protect against challenge with Bacillus anthracis, in a murine model. Pre-pulsing murine BMDC with either recombinant Protective Antigen (PA or CpG significantly upregulated expression of the activation markers CD40, CD80, CD86 and MHC-II. Passive transfusion of mice with pulsed BMDC, concurrently with active immunisation with rPA in alum, significantly enhanced (p<0.001 PA-specific splenocyte responses seven days post-immunisation. Parallel studies using ex vivo DCs expanded from human peripheral blood and activated under the same conditions as the murine DC, demonstrated that human DCs had a PA dose-related significant increase in the markers CD40, CD80 and CCR7 and that the increases in CD40 and CD80 were maintained when the other activating components, CpG and HK B. anthracis were added to the rPA in culture. Mice vaccinated on a single occasion intra-muscularly with rPA and alum and concurrently transfused intra-dermally with pulsed BMDC, demonstrated 100% survival following lethal B. anthracis challenge and had significantly enhanced (p<0.05 bacterial clearance within 2 days, compared with mice vaccinated with rPA and alum alone.

  5. Active properties of neuronal dendrites.

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    Johnston, D; Magee, J C; Colbert, C M; Cristie, B R

    1996-01-01

    Dendrites of neurons in the central nervous system are the principal sites for excitatory synaptic input. Although little is known about their function, two disparate perspectives have arisen to describe the activity patterns inherent to these diverse tree-like structures. Dendrites are thus considered either passive or active in their role in integrating synaptic inputs. This review follows the history of dendritic research from before the turn of the century to the present, with a primary focus on the hippocampus. A number of recent techniques, including high-speed fluorescence imaging and dendritic patch clamping, have provided new information and perspectives about the active properties of dendrites. The results support previous notions about the dendritic propagation of action potentials and also indicate which types of voltage-gated sodium and calcium channels are expressed and functionally active in dendrites. Possible roles for the active properties of dendrites in synaptic plasticity and integration are also discussed.

  6. Ultrathin dendritic Pt3Cu triangular pyramid caps with enhanced electrocatalytic activity.

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    Kuang, Yun; Cai, Zhao; Zhang, Ying; He, Dongsheng; Yan, Xiuling; Bi, Yongmin; Li, Yaping; Li, Ziyou; Sun, Xiaoming

    2014-10-22

    Here we report on the synthesis of novel dendritic Pt3Cu triangular pyramid caps via a solvothermal coreduction method. These caps had three-dimensional caved structures with ultrathin branches, as evidenced by high-resolution transmission electron microscopy (HRTEM) and HAADF-STEM characterization. Tuning the reduction kinetics of two metal precursors by an iodide ion was believed to be the key for the formation of an alloyed nanostructure. Electro-oxidation of methanol and formic acid showed dramatically improved electrocatalytic activities and poison-tolerance for these nanoalloys as compared to commercial Pt/C catalysts, which was attributed to their unique open porous structure with interconnected network, ultrahigh surface areas, as well as synergetic effect of the two metallic components.

  7. Levamisole enhances immune response by affecting the activation and maturation of human monocyte-derived dendritic cells

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    Chen, L-Y; Lin, Y-L; Chiang, B-L

    2008-01-01

    Levamisole is a synthetic phenylimidazolthiazole that was first introduced in 1966 as an anti-helmintic agent. Current studies have been focused upon its effect on immune response and on cancer treatment. We examined the molecular mechanisms of levamisole in the activation and maturation of human monocyte-derived dendritic cells (DC) and human T cells. Treatment of DC with levamisole increased the presentation of CD80, CD86, CD83 and human leucocyte antigen D-related (HLA-DR) molecules on the cell membrane, as well as the production of interleukin (IL)-12 p40 and IL-10. Levamisole-treated human DC also enhanced T cell activation towards type 1 T helper immune response by inducing interferon-γ secretion. Neutralization with antibodies against Toll-like receptor (TLR)-2 inhibited levamisole-induced production of IL-12 p40 and IL-10, suggesting a vital role for TLR-2 in signalling DC upon incubation with levamisole. The inhibition of nuclear factor-κB, extracellular signal-regulated kinases 1/2 or c-Jun N-terminal kinases pathways also prevented the effects of levamisole on DC in producing IL-12 p40 or IL-10. Taken together, levamisole could enhance immune response towards T helper 1 development through the activation of dendritic cells or T cell aspects. PMID:18005262

  8. Glucocorticoid-Induced TNFR family Related gene (GITR) enhances dendritic cell activity.

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    Ronchetti, Simona; Nocentini, Giuseppe; Petrillo, Maria Grazia; Bianchini, Rodolfo; Sportoletti, Paolo; Bastianelli, Alessandra; Ayroldi, Emira M; Riccardi, Carlo

    2011-03-30

    Glucocorticoid-Induced TNFR family Related gene (GITR), a Tumor Necrosis Factor Receptor Superfamily (TNFRSF) member involved in immune/inflammatory processes, has been previously shown to regulate T cell activation. To study GITR role in antigen presenting cells, we evaluated the capability of bone marrow derived dendritic cells (BMDC) from GITR(-/-) mice to stimulate the activation of CD4(+)CD25(-) T lymphocytes. We found that GITR(-/-) BMDC are weaker stimulators of T cell proliferation than GITR(+/+) BMDC, either in syngenic or allogenic BMDC/T cell co-cultures. Expression of GITR in GITR(-/-) BMDC restored their ability to activate T cells while GITR silencing in GITR(+/+) BMDC inhibited the capability to stimulate T cells. GITR(-/-) BMDC showed a reduced production of the pro-inflammatory cytokine IL-6 and an increased production of the anti-inflammatory cytokine IL-10. Notably, co-culture of CD4(+)CD25(-) cells with GITR(-/-) BMDC originated FoxP3(+) cells, secreting IL-10 and TGF-β. Finally, in vivo injection of GITR(-/-) OVA-loaded BMDC led to a lower cell number and a lower activated cell number in draining lymph nodes than in GITR(+/+) OVA-loaded BMDC injected mice. Together, these results indicate that GITR plays a role in regulating BMDC activity.

  9. Activation of the inflammasome and enhanced migration of microparticle-stimulated dendritic cells to the draining lymph node.

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    Meraz, Ismail M; Melendez, Brenda; Gu, Jianhua; Wong, Stephen T C; Liu, Xuewu; Andersson, Helen A; Serda, Rita E

    2012-07-02

    Porous silicon microparticles presenting pathogen-associated molecular patterns mimic pathogens, enhancing internalization of the microparticles and activation of antigen presenting dendritic cells. We demonstrate abundant uptake of microparticles bound by the TLR-4 ligands LPS and MPL by murine bone marrow-derived dendritic cells (BMDC). Labeled microparticles induce concentration-dependent production of IL-1β, with inhibition by the caspase inhibitor Z-VAD-FMK supporting activation of the NLRP3-dependent inflammasome. Inoculation of BALB/c mice with ligand-bound microparticles induces a significant increase in circulating levels of IL-1β, TNF-α, and IL-6. Stimulation of BMDC with ligand-bound microparticles increases surface expression of costimulatory and MHC molecules, and enhances migration of BMDC to the draining lymph node. LPS-microparticles stimulate in vivo C57BL/6 BMDC and OT-1 transgenic T cell interactions in the presence of OVA SIINFEKL peptide in lymph nodes, with intact nodes imaged using two-photon microscopy. Formation of in vivo and in vitro immunological synapses between BMDC, loaded with OVA peptide and LPS-microparticles, and OT-1 T cells are presented, as well as elevated intracellular interferon gamma levels in CD8(+) T cells stimulated by BMDC carrying peptide-loaded microparticles. In short, ligand-bound microparticles enhance (1) phagocytosis of microparticles; (2) BMDC inflammasome activation and upregulation of costimulatory and MHC molecules; (3) cellular migration of BMDC to lymphatic tissue; and (4) cellular interactions leading to T cell activation in the presence of antigen.

  10. Immature human dendritic cells enhance their migration through KCa3.1 channel activation.

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    Crottès, David; Félix, Romain; Meley, Daniel; Chadet, Stéphanie; Herr, Florence; Audiger, Cindy; Soriani, Olivier; Vandier, Christophe; Roger, Sébastien; Angoulvant, Denis; Velge-Roussel, Florence

    2016-04-01

    Migration capacity is essential for dendritic cells (DCs) to present antigen to T cells for the induction of immune response. The DC migration is supposed to be a calcium-dependent process, while not fully understood. Here, we report a role of the KCa3.1/IK1/SK4 channels in the migration capacity of both immature (iDC) and mature (mDC) human CD14(+)-derived DCs. KCa3.1 channels were shown to control the membrane potential of human DC and the Ca(2+) entry, which is directly related to migration capacities. The expression of migration marker such as CCR5 and CCR7 was modified in both types of DCs by TRAM-34 (100nM). But, only the migration of iDC was decreased by use of both TRAM-34 and KCa3.1 siRNA. Confocal analyses showed a close localization of CCR5 with KCa3.1 in the steady state of iDC. Finally, the implication of KCa3.1 seems to be limited to the migration capacities as T cell activation of DCs appeared unchanged. Altogether, these results demonstrated that KCa3.1 channels have a pro-migratory effect on iDC migration. Our findings suggest that KCa3.1 in human iDC play a major role in their migration and constitute an attractive target for the cell therapy optimization.

  11. Dendritic Cell-Mediated Phagocytosis but Not Immune Activation Is Enhanced by Plasmin.

    OpenAIRE

    Borg, Rachael J.; Samson, Andre L.; Amanda E-L Au; Anja Scholzen; Martina Fuchsberger; Kong, Ying Y.; Roxann Freeman; Nicole A Mifsud; Magdalena Plebanski; Medcalf, Robert L.

    2015-01-01

    Removal of dead cells in the absence of concomitant immune stimulation is essential for tissue homeostasis. We recently identified an injury-induced protein misfolding event that orchestrates the plasmin-dependent proteolytic degradation of necrotic cells. As impaired clearance of dead cells by the innate immune system predisposes to autoimmunity, we determined whether plasmin could influence endocytosis and immune cell stimulation by dendritic cells - a critical cell that links the innate an...

  12. The Novel Toll-Like Receptor 2 Agonist SUP3 Enhances Antigen Presentation and T Cell Activation by Dendritic Cells

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    Guo, Xueheng; Wu, Ning; Shang, Yingli; Liu, Xin; Wu, Tao; Zhou, Yifan; Liu, Xin; Huang, Jiaoyan; Liao, Xuebin; Wu, Li

    2017-01-01

    Dendritic cells (DCs) are highly specialized antigen-presenting cells that play crucial roles in innate and adaptive immunity. Previous studies suggested that Toll-like receptor (TLR) agonists could be used as potential adjuvants, as activation of TLRs can boost DC-induced immune responses. TLR2 agonists have been shown to enhance DC-mediated immune responses. However, classical TLR2 agonists such as Pam3CSK4 are not stable enough in vivo, which limits their clinical applications. In this study, a novel structurally stable TLR2 agonist named SUP3 was designed. Functional analysis showed that SUP3 induced much stronger antitumor response than Pam3CSK4 by promoting cytotoxic T lymphocytes activation in vivo. This effect was achieved through the following mechanisms: SUP3 strongly enhanced the ability of antigen cross-presentation by DCs and subsequent T cell activation. SUP3 upregulated the expression of costimulatory molecules on DCs and increased antigen deposition in draining lymph nodes. More interestingly, SUP3 induced less amount of pro-inflammatory cytokine production in vivo compared to other TLR agonists such as lipopolysaccharide. Taken together, SUP3 could serve as a novel promising immune adjuvant in vaccine development and immune modulations.

  13. Infection of human monocyte-derived dendritic cells by ANDES Hantavirus enhances pro-inflammatory state, the secretion of active MMP-9 and indirectly enhances endothelial permeability

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    Lopez-Lastra Marcelo

    2011-05-01

    Full Text Available Abstract Background Andes virus (ANDV, a rodent-borne Hantavirus, is the major etiological agent of Hantavirus cardiopulmonary syndrome (HCPS in South America, which is mainly characterized by a vascular leakage with high rate of fatal outcomes for infected patients. Currently, neither specific therapy nor vaccines are available against this pathogen. ANDV infects both dendritic and epithelial cells, but in despite that the severity of the disease directly correlates with the viral RNA load, considerable evidence suggests that immune mechanisms rather than direct viral cytopathology are responsible for plasma leakage in HCPS. Here, we assessed the possible effect of soluble factors, induced in viral-activated DCs, on endothelial permeability. Activated immune cells, including DC, secrete gelatinolytic matrix metalloproteases (gMMP-2 and -9 that modulate the vascular permeability for their trafficking. Methods A clinical ANDES isolate was used to infect DC derived from primary PBMC. Maturation and pro-inflammatory phenotypes of ANDES-infected DC were assessed by studying the expression of receptors, cytokines and active gMMP-9, as well as some of their functional status. The ANDES-infected DC supernatants were assessed for their capacity to enhance a monolayer endothelial permeability using primary human vascular endothelial cells (HUVEC. Results Here, we show that in vitro primary DCs infected by a clinical isolate of ANDV shed virus RNA and proteins, suggesting a competent viral replication in these cells. Moreover, this infection induces an enhanced expression of soluble pro-inflammatory factors, including TNF-α and the active gMMP-9, as well as a decreased expression of anti-inflammatory cytokines, such as IL-10 and TGF-β. These viral activated cells are less sensitive to apoptosis. Moreover, supernatants from ANDV-infected DCs were able to indirectly enhance the permeability of a monolayer of primary HUVEC. Conclusions Primary human DCs

  14. Protein-bound polysaccharide activates dendritic cells and enhances OVA-specific T cell response as vaccine adjuvant.

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    Engel, Abbi L; Sun, Guan-Cheng; Gad, Ekram; Rastetter, Lauren R; Strobe, Katie; Yang, Yi; Dang, Yushe; Disis, Mary L; Lu, Hailing

    2013-12-01

    Protein-bound polysaccharide-K (PSK) is a hot water extract from Trametes versicolor mushroom. It has been used traditionally in Asian countries for its immune stimulating and anti-cancer effects. We have recently found that PSK can activate Toll-like receptor 2 (TLR2). TLR2 is highly expressed on dendritic cells (DC), so the current study was undertaken to evaluate the effect of PSK on DC activation and the potential of using PSK as a vaccine adjuvant. In vitro experiments using mouse bone marrow-derived DC (BMDC) demonstrated that PSK induces DC maturation as shown by dose-dependent increase in the expression of CD80, CD86, MHCII, and CD40. PSK also induces the production of multiple inflammatory cytokines by DC, including IL-12, TNF-α, and IL-6, at both mRNA and protein levels. In vivo experiments using PSK as an adjuvant to OVAp323-339 vaccine showed that PSK as adjuvant leads to enlarged draining lymph nodes with higher number of activated DC. PSK also stimulates proliferation of OVA-specific T cells, and induces T cells that produce multiple cytokines, IFN-γ, IL-2, and TNF-α. Altogether, these results demonstrate the ability of PSK to activate DC in vitro and in vivo and the potential of using PSK as a novel vaccine adjuvant.

  15. Toll-like receptor activation enhances cell-mediated immunity induced by an antibody vaccine targeting human dendritic cells

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    Berger Marc A

    2007-01-01

    Full Text Available Abstract Previously, we have successfully targeted the mannose receptor (MR expressed on monocyte-derived dendritic cells (DCs using a fully human MR-specific antibody, B11, as a vehicle to deliver whole protein tumor antigens such as the human chorionic gonadotropin hormone (hCGβ. Since MRs play a role in bridging innate immunity with adaptive immunity we have explored several toll-like receptor (TLR-specific ligands that may synergize with MR targeting and be applicable as adjuvants in the clinic. We demonstrate that antigen-specific helper and cytolytic T cells from both healthy donors and cancer patients were effectively primed with B11-hCGβ-treated autologous DCs when a combination of one or several TLR ligands is used. Specifically, concomitant signaling of DCs via TLR3 with dsRNA (poly I:C and DC TLR 7/8 with Resiquimod (R-848, respectively, elicited efficient antigen presentation-mediated by MR-targeting. We demonstrate that MR and TLRs contribute towards maturation and activation of DCs by a mechanism that may be driven by a combination of adjuvant and antibody vaccines that specifically deliver antigenic targets to DCs.

  16. Mulifunctional Dendritic Emitter: Aggregation-Induced Emission Enhanced, Thermally Activated Delayed Fluorescent Material for Solution-Processed Multilayered Organic Light-Emitting Diodes

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    Matsuoka, Kenichi; Albrecht, Ken; Yamamoto, Kimihisa; Fujita, Katsuhiko

    2017-01-01

    Thermally activated delayed fluorescence (TADF) materials emerged as promising light sources in third generation organic light-emitting diodes (OLED). Much effort has been invested for the development of small molecular TADF materials and vacuum process-based efficient TADF-OLEDs. In contrast, a limited number of solution processable high-molecular weight TADF materials toward low cost, large area, and scalable manufacturing of solution processed TADF-OLEDs have been reported so far. In this context, we report benzophenone-core carbazole dendrimers (GnB, n = generation) showing TADF and aggregation-induced emission enhancement (AIEE) properties along with alcohol resistance enabling further solution-based lamination of organic materials. The dendritic structure was found to play an important role for both TADF and AIEE activities in the neat films. By using these multifunctional dendritic emitters as non-doped emissive layers, OLED devices with fully solution processed organic multilayers were successfully fabricated and achieved maximum external quantum efficiency of 5.7%.

  17. [Ag85B and BCG enhance immune activity of dendritic cells in patients with initially treated tuberculosis].

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    Guo, Yun; Su, Yuanyuan; Sun, Yang; Guan, Weiwei; Yang, Li; Zhang, Zhi; Wang, Yuling; Dai, Erhei

    2016-06-01

    Objective To investigate the regulatory effects of Mycobacterium tuberculosis major secreted protein Ag85B and Bacillus Calmette-Guerin (BCG) on the immune function of dendritic cells (DCs) in the patients with tuberculosis who have received an initial treatment. Methods The peripheral blood mononuclear cells were collected and separated in 26 healthy subjects and 31 patients with tuberculosis who had been treated initially. Every specimen was divided into 4 groups and DCs were induced and cultured. On the 6th day, the DCs in the three experimental groups were treated by lipopolysaccharide (LPS), BCG, Ag85B, respectively and no-treated DCs served as a control group. After 24-hour treatment, DCs were collected and examined for the levels of CD83, CD86, HLA-DR and CD11c using flow cytometry. Moreover, the levels of interleukin 12 (IL-12), IL-10 and interferon γ (IFN-γ) in the supernatants were measured by ELISA. Results The expression levels of CD83 and IL-10 in the patient control group were significantly lower than those in healthy subject control group. The levels of CD83, CD86 and IFN-γ in the Ag85B treated group were obviously high than those in the control group. The level of IFN-γ in the BCG treated group was significantly high than that in the control group. The levels of CD83, CD86, HLA-DR and IL-10 in the LPS treated group were remarkably higher than those in the control group. The levels of CD83, CD86 and IL-10 in the healthy subject LPS treated group were significantly higher than those in the healthy subject control group. Conclusion The immune-enhancing effect of Ag85B on DCs is superior to that of BCG in the patients with initially treated tuberculosis.

  18. HIV-1 Nef enhances dendritic cell-mediated viral transmission to CD4+ T cells and promotes T-cell activation.

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    Corine St Gelais

    Full Text Available HIV-1 Nef enhances dendritic cell (DC-mediated viral transmission to CD4(+ T cells, but the underlying mechanism is not fully understood. It is also unknown whether HIV-1 infected DCs play a role in activating CD4(+ T cells and enhancing DC-mediated viral transmission. Here we investigated the role of HIV-1 Nef in DC-mediated viral transmission and HIV-1 infection of primary CD4(+ T cells using wild-type HIV-1 and Nef-mutated viruses. We show that HIV-1 Nef facilitated DC-mediated viral transmission to activated CD4(+ T cells. HIV-1 expressing wild-type Nef enhanced the activation and proliferation of primary resting CD4(+ T cells. However, when co-cultured with HIV-1-infected autologous DCs, there was no significant trend for infection- or Nef-dependent proliferation of resting CD4(+ T cells. Our results suggest an important role of Nef in DC-mediated transmission of HIV-1 to activated CD4(+ T cells and in the activation and proliferation of resting CD4(+ T cells, which likely contribute to viral pathogenesis.

  19. Expansion and Activation of CD103(+) Dendritic Cell Progenitors at the Tumor Site Enhances Tumor Responses to Therapeutic PD-L1 and BRAF Inhibition.

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    Salmon, Hélène; Idoyaga, Juliana; Rahman, Adeeb; Leboeuf, Marylène; Remark, Romain; Jordan, Stefan; Casanova-Acebes, Maria; Khudoynazarova, Makhzuna; Agudo, Judith; Tung, Navpreet; Chakarov, Svetoslav; Rivera, Christina; Hogstad, Brandon; Bosenberg, Marcus; Hashimoto, Daigo; Gnjatic, Sacha; Bhardwaj, Nina; Palucka, Anna Karolina; Brown, Brian D; Brody, Joshua; Ginhoux, Florent; Merad, Miriam

    2016-04-19

    Large numbers of melanoma lesions develop resistance to targeted inhibition of mutant BRAF or fail to respond to checkpoint blockade. We explored whether modulation of intratumoral antigen-presenting cells (APCs) could increase responses to these therapies. Using mouse melanoma models, we found that CD103(+) dendritic cells (DCs) were the only APCs transporting intact antigens to the lymph nodes and priming tumor-specific CD8(+) T cells. CD103(+) DCs were required to promote anti-tumoral effects upon blockade of the checkpoint ligand PD-L1; however, PD-L1 inhibition only led to partial responses. Systemic administration of the growth factor FLT3L followed by intratumoral poly I:C injections expanded and activated CD103(+) DC progenitors in the tumor, enhancing responses to BRAF and PD-L1 blockade and protecting mice from tumor rechallenge. Thus, the paucity of activated CD103(+) DCs in tumors limits checkpoint-blockade efficacy and combined FLT3L and poly I:C therapy can enhance tumor responses to checkpoint and BRAF blockade.

  20. Radical-containing particles activate dendritic cells and enhance Th17 inflammation in a mouse model of asthma.

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    Wang, Pingli; Thevenot, Paul; Saravia, Jordy; Ahlert, Terry; Cormier, Stephania A

    2011-11-01

    We identified a previously unrecognized component of airborne particulate matter (PM) formed in combustion and thermal processes, namely, environmentally persistent free radicals (EPFRs). The pulmonary health effects of EPFRs are currently unknown. In the present study, we used a model EPFR-containing pollutant-particle system referred to as MCP230. We evaluated the effects of MCP230 on the phenotype and function of bone marrow-derived dendritic cells (BMDCs) in vitro and lung dendritic cells (DCs) in vivo, and the subsequent T-cell response. We also investigated the adjuvant role of MCP230 on airway inflammation in a mouse model of asthma. MCP230 decreased intracellular reduced glutathione (GSH) and the GSH/oxidized glutathione ratio in BMDCs, and up-regulated the expression of costimulatory molecules CD80 and CD86 on DCs. The maturation of DCs was blocked by inhibiting oxidative stress or the uptake of MCP230. BMDCs exposed to MCP230 increased their antigen-specific T-cell proliferation in vitro. In a model of asthma, exposure to MCP230 exacerbated pulmonary inflammation, which was attributed to the increase of neutrophils and macrophages but not eosinophils. This result correlated with an increase in Th17 cells and cytokines, compared with non-MCP230-treated but ovalbumin (OVA)-challenged mice. The percentage of Th2 cells was comparable between OVA and OVA + MCP230 mice. Our data demonstrate that combustion-generated, EPFR-containing PM directly induced the maturation of DCs in an uptake-dependent and oxidative stress-dependent manner. Furthermore, EPFR-containing PM induced a Th17-biased phenotype in lung, accompanied by significant pulmonary neutrophilia. Exposure to EPFR-containing PM may constitute an important and unrecognized risk factor in the exacerbation and development of a severe asthma phenotype in humans.

  1. Methamphetamine Enhances HIV-1 Infectivity in Monocyte Derived Dendritic Cells

    OpenAIRE

    2008-01-01

    The US is currently experiencing an epidemic of methamphetamine (Meth) use as a recreational drug. Recent studies also show a high prevalence of HIV-1 infection among Meth users. We report that Meth enhances HIV-1 infectivity of dendritic cells as measured by multinuclear activation of a galactosidase indicator (MAGI) cell assay, p24 assay, and LTR-RU5 amplification. Meth induces increased HIV-1 infection in association with an increase in the HIV-1 coreceptors, CXCR4 and CCR5, and infection ...

  2. Dynamic Range of Vertebrate Retina Ganglion Cells: Importance of Active Dendrites and Coupling by Electrical Synapses

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    Publio, Rodrigo; Ceballos, Cesar Celis; Roque, Antonio C.

    2012-01-01

    The vertebrate retina has a very high dynamic range. This is due to the concerted action of its diverse cell types. Ganglion cells, which are the output cells of the retina, have to preserve this high dynamic range to convey it to higher brain areas. Experimental evidence shows that the firing response of ganglion cells is strongly correlated with their total dendritic area and only weakly correlated with their dendritic branching complexity. On the other hand, theoretical studies with simple neuron models claim that active and large dendritic trees enhance the dynamic range of single neurons. Theoretical models also claim that electrical coupling between ganglion cells via gap junctions enhances their collective dynamic range. In this work we use morphologically reconstructed multi-compartmental ganglion cell models to perform two studies. In the first study we investigate the relationship between single ganglion cell dynamic range and number of dendritic branches/total dendritic area for both active and passive dendrites. Our results support the claim that large and active dendrites enhance the dynamic range of a single ganglion cell and show that total dendritic area has stronger correlation with dynamic range than with number of dendritic branches. In the second study we investigate the dynamic range of a square array of ganglion cells with passive or active dendritic trees coupled with each other via dendrodendritic gap junctions. Our results suggest that electrical coupling between active dendritic trees enhances the dynamic range of the ganglion cell array in comparison with both the uncoupled case and the coupled case with cells with passive dendrites. The results from our detailed computational modeling studies suggest that the key properties of the ganglion cells that endow them with a large dynamic range are large and active dendritic trees and electrical coupling via gap junctions. PMID:23144767

  3. Dynamic range of vertebrate retina ganglion cells: importance of active dendrites and coupling by electrical synapses.

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    Publio, Rodrigo; Ceballos, Cesar Celis; Roque, Antonio C

    2012-01-01

    The vertebrate retina has a very high dynamic range. This is due to the concerted action of its diverse cell types. Ganglion cells, which are the output cells of the retina, have to preserve this high dynamic range to convey it to higher brain areas. Experimental evidence shows that the firing response of ganglion cells is strongly correlated with their total dendritic area and only weakly correlated with their dendritic branching complexity. On the other hand, theoretical studies with simple neuron models claim that active and large dendritic trees enhance the dynamic range of single neurons. Theoretical models also claim that electrical coupling between ganglion cells via gap junctions enhances their collective dynamic range. In this work we use morphologically reconstructed multi-compartmental ganglion cell models to perform two studies. In the first study we investigate the relationship between single ganglion cell dynamic range and number of dendritic branches/total dendritic area for both active and passive dendrites. Our results support the claim that large and active dendrites enhance the dynamic range of a single ganglion cell and show that total dendritic area has stronger correlation with dynamic range than with number of dendritic branches. In the second study we investigate the dynamic range of a square array of ganglion cells with passive or active dendritic trees coupled with each other via dendrodendritic gap junctions. Our results suggest that electrical coupling between active dendritic trees enhances the dynamic range of the ganglion cell array in comparison with both the uncoupled case and the coupled case with cells with passive dendrites. The results from our detailed computational modeling studies suggest that the key properties of the ganglion cells that endow them with a large dynamic range are large and active dendritic trees and electrical coupling via gap junctions.

  4. Interleukin-4 enhances trafficking and functional activities of GM-CSF-stimulated mouse myeloid-derived dendritic cells at late differentiation stage

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    Yin, Shu-Yi, E-mail: in_shuyi@hotmail.com [Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan, ROC (China); Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan, ROC (China); Taiwan International Graduate Program (TIGP), Molecular and Biological Agricultural Sciences Program, Academia Sinica, Taipei, Taiwan, ROC (China); Wang, Chien-Yu, E-mail: sallywang1973@hotmail.com [Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan, ROC (China); Yang, Ning-Sun, E-mail: nsyang@gate.sinica.edu.tw [Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan, ROC (China); Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan, ROC (China); Taiwan International Graduate Program (TIGP), Molecular and Biological Agricultural Sciences Program, Academia Sinica, Taipei, Taiwan, ROC (China)

    2011-09-10

    Mouse bone marrow-derived dendritic cells (BMDCs) are being employed as an important model for translational research into the development of DC-based therapeutics. For such use, the localization and specialized mobility of injected BMDCs within specific immune tissues are known to define their immunity and usefulness in vivo. In this study, we demonstrate that IL-4, a key driving factor for in vitro propagation and differentiation of BMDCs, when added during a late culture stage can enhance the in vivo trafficking activity of granulocyte-macrophage colony-stimulating factor (GM-CSF)-induced BMDCs. It suggests that the temporal control of IL-4 stimulation during the in vitro generation of DCs drastically affects the DC trafficking efficiency in vivo. With this modification of IL-4 stimulation, we also show that much less cytokine was needed to generate BMDCs with high purity and yield that secrete a high level of cytokines and possess a good capacity to induce proliferation of allogeneic CD4{sup +}T cells, as compared to the conventional method that uses a continuous supplement of GM-CSF and IL-4 throughout cultivation. These results provide us with an important know-how for differentiation of BMDCs from myeloid stem cells, and for use of other immune cells in related medical or stem cell applications.

  5. Sequence learning in differentially activated dendrites

    DEFF Research Database (Denmark)

    Nielsen, Bjørn Gilbert

    2003-01-01

    . It is proposed that the neural machinery required in such a learning/retrieval mechanism could involve the NMDA receptor, in conjunction with the ability of dendrites to maintain differentially activated regions. In particular, it is suggested that such a parcellation of the dendrite allows the neuron...... to participate in multiple sequences, which can be learned without suffering from the 'wash-out' of synaptic efficacy associated with superimposition of training patterns. This is a biologically plausible solution to the stability-plasticity dilemma of learning in neural networks....

  6. Sensory-Driven Enhancement of Calcium Signals in Individual Purkinje Cell Dendrites of Awake Mice

    Directory of Open Access Journals (Sweden)

    Farzaneh Najafi

    2014-03-01

    Full Text Available Climbing fibers (CFs are thought to contribute to cerebellar plasticity and learning by triggering a large influx of dendritic calcium in the postsynaptic Purkinje cell (PC to signal the occurrence of an unexpected sensory event. However, CFs fire about once per second whether or not an event occurs, raising the question of how sensory-driven signals might be distinguished from a background of ongoing spontaneous activity. Here, we report that in PC dendrites of awake mice, CF-triggered calcium signals are enhanced when the trigger is a sensory event. In addition, we show that a large fraction of the total enhancement in each PC dendrite can be accounted for by an additional boost of calcium provided by sensory activation of a non-CF input. We suggest that sensory stimulation may modulate dendritic voltage and calcium concentration in PCs to increase the strength of plasticity signals during cerebellar learning.

  7. Role of active dendritic conductances in subthreshold input integration

    OpenAIRE

    Rinzel John; Remme Michiel

    2010-01-01

    Dendrites of many types of neurons contain voltage-dependent conductances that are active at subthreshold membrane potentials. To understand the computations neurons perform it is key to understand the role of active dendrites in the subthreshold processing of synaptic inputs. We examine systematically how active dendritic conductances affect the time course of postsynaptic potentials propagating along dendrites, and how they affect the interaction between such signals. Voltage-dependent curr...

  8. The microvesicle component of HIV-1 inocula modulates dendritic cell infection and maturation and enhances adhesion to and activation of T lymphocytes.

    Directory of Open Access Journals (Sweden)

    Sarah K Mercier

    2013-10-01

    Full Text Available HIV-1 is taken up by immature monocyte derived dendritic cells (iMDDCs into tetraspanin rich caves from which the virus can either be transferred to T lymphocytes or enter into endosomes resulting in degradation. HIV-1 binding and fusion with the DC membrane results in low level de novo infection that can also be transferred to T lymphocytes at a later stage. We have previously reported that HIV-1 can induce partial maturation of iMDDCs at both stages of trafficking. Here we show that CD45⁺ microvesicles (MV which contaminate purified HIV-1 inocula due to similar size and density, affect DC maturation, de novo HIV-1 infection and transfer to T lymphocytes. Comparing iMDDCs infected with CD45-depleted HIV-1BaL or matched non-depleted preparations, the presence of CD45⁺ MVs was shown to enhance DC maturation and ICAM-1 (CD54 expression, which is involved in DC∶T lymphocyte interactions, while restricting HIV-1 infection of MDDCs. Furthermore, in the DC culture HIV-1 infected (p24⁺ MDDCs were more mature than bystander cells. Depletion of MVs from the HIV-1 inoculum markedly inhibited DC∶T lymphocyte clustering and the induction of alloproliferation as well as limiting HIV-1 transfer from DCs to T lymphocytes. The effects of MV depletion on these functions were reversed by the re-addition of purified MVs from activated but not non-activated SUPT1.CCR5-CL.30 or primary T cells. Analysis of the protein complement of these MVs and of these HIV-1 inocula before and after MV depletion showed that Heat Shock Proteins (HSPs and nef were the likely DC maturation candidates. Recombinant HSP90α and β and nef all induced DC maturation and ICAM-1 expression, greater when combined. These results suggest that MVs contaminating HIV-1 released from infected T lymphocytes may be biologically important, especially in enhancing T cell activation, during uptake by DCs in vitro and in vivo, particularly as MVs have been detected in the circulation of HIV-1

  9. Enhanced interferon-γ secretion and antitumor activity of T-lymphocytes activated by dendritic cells loaded with glycoengineered myeloma antigens

    Institute of Scientific and Technical Information of China (English)

    XIONG Hong; WU Qiu-ye; HU Hong-gang; LIU Ban; GUO Zhong-wu; Daniel Man-yuan Sze; HOU Jian

    2007-01-01

    Background Immunotherapy is emerging as a promising cure for cancer. However, a severe problem in this area is the immune tolerance to tumor cells and tumor-associated antigens, as evidenced by the ability of cancer to escape immune surveillance. To overcome this problem this work examined the potential of improving the antigenicity of myeloma by metabolic engineering of its cell surface carbohydrate antigens (i.e., glycoengineering) and presentation of the modified tumor antigens by dendritic cells (DCs) to generate cytotoxic T-lymphocytes (CTLs).Methods CD138+ myeloma cells were isolated from 11 multipe myeloma (MM) patients by the immunomagnetic bead method. The MM cells were treated with N-propionyl-D-mannosamine (ManNPr), a synthetic analog of N-acetyl-D-mannosamine (ManNAc), the natural biosynthetic precursor of N-acetyl sialic acid (NeuNAc), to express unnatural N-propionylated sialoglycans. The giycoengineered cells were then induced to apoptosis, and the apoptotic products were added to cultured functional DCs that could present the unnatural carbohydrate antigens to autologous T-lymphocytes.Results It was found that the resultant DCs could activate CD4+ and CD8+ T-lymphocytes, resulting in increased expression of T cell surface markers, including CD8CD28 and CD4CD29. Moreover, upon stimulation by glycoengineered MM cells, these DC-activated T-lymphocytes could release significantly higher levels of IFN-γ (P<0.05).Lactate dehydrogenase (LDH) assays further showed that the stimulated T-lymphocytes were cytotoxic to glycoengineered MM cells.Conclusions This work demonstrated that glycoengineered myeloma cells were highly antigenic and the CTLs induced by the DCs loaded with the unnatural myeloma antigens were specifically cytotoxic to the glycoengineered myeloma.This may provide a new strategy for overcoming the problem of immune tolerance for the development of effective immunotherapies for MM.

  10. LTP is accompanied by an enhanced local excitability of pyramidal neuron dendrites.

    Science.gov (United States)

    Frick, Andreas; Magee, Jeffrey; Johnston, Daniel

    2004-02-01

    The propagation and integration of signals in the dendrites of pyramidal neurons is regulated, in part, by the distribution and biophysical properties of voltage-gated ion channels. It is thus possible that any modification of these channels in a specific part of the dendritic tree might locally alter these signaling processes. Using dendritic and somatic whole-cell recordings, combined with calcium imaging in rat hippocampal slices, we found that the induction of long-term potentiation (LTP) was accompanied by a local increase in dendritic excitability that was dependent on the activation of NMDA receptors. These changes favored the back-propagation of action potentials into this dendritic region with a subsequent boost in the Ca(2+) influx. Dendritic cell-attached patch recordings revealed a hyperpolarized shift in the inactivation curve of transient, A-type K(+) currents that can account for the enhanced excitability. These results suggest an important mechanism associated with LTP for shaping signal processing and controlling dendritic function.

  11. Activated protein C modulates the proinflammatory activity of dendritic cells

    Directory of Open Access Journals (Sweden)

    Matsumoto T

    2015-05-01

    Full Text Available Takahiro Matsumoto,1,2* Yuki Matsushima,1* Masaaki Toda,1 Ziaurahman Roeen,1 Corina N D'Alessandro-Gabazza,1,5 Josephine A Hinneh,1 Etsuko Harada,1,3 Taro Yasuma,4 Yutaka Yano,4 Masahito Urawa,1,5 Tetsu Kobayashi,5 Osamu Taguchi,5 Esteban C Gabazza1 1Department of Immunology, Mie University Graduate School of Medicine, Tsu, Mie Prefecture, 2BONAC Corporation, BIO Factory 4F, Fukuoka, 3Iwade Research Institute of Mycology, 4Department of Endocrinology, Diabetes and Metabolism, 5Department of Pulmonary and Critical Care Medicine, Mie University Graduate School of Medicine, Tsu, Mie Prefecture, Japan *These authors contributed equally to this work Background: Previous studies have demonstrated the beneficial activity of activated protein C in allergic diseases including bronchial asthma and rhinitis. However, the exact mechanism of action of activated protein C in allergies is unclear. In this study, we hypothesized that pharmacological doses of activated protein C can modulate allergic inflammation by inhibiting dendritic cells. Materials and methods: Dendritic cells were prepared using murine bone marrow progenitor cells and human peripheral monocytes. Bronchial asthma was induced in mice that received intratracheal instillation of ovalbumin-pulsed dendritic cells. Results: Activated protein C significantly increased the differentiation of tolerogenic plasmacytoid dendritic cells and the secretion of type I interferons, but it significantly reduced lipopolysaccharide-mediated maturation and the secretion of inflammatory cytokines in myeloid dendritic cells. Activated protein C also inhibited maturation and the secretion of inflammatory cytokines in monocyte-derived dendritic cells. Activated protein C-treated dendritic cells were less effective when differentiating naïve CD4 T-cells from Th1 or Th2 cells, and the cellular effect of activated protein C was mediated by its receptors. Mice that received adoptive transfer of activated protein C

  12. Hierarchical Pd-Sn alloy nanosheet dendrites: an economical and highly active catalyst for ethanol electrooxidation.

    Science.gov (United States)

    Ding, Liang-Xin; Wang, An-Liang; Ou, Yan-Nan; Li, Qi; Guo, Rui; Zhao, Wen-Xia; Tong, Ye-Xiang; Li, Gao-Ren

    2013-01-01

    Hierarchical alloy nanosheet dendrites (ANSDs) are highly favorable for superior catalytic performance and efficient utilization of catalyst because of the special characteristics of alloys, nanosheets, and dendritic nanostructures. In this paper, we demonstrate for the first time a facile and efficient electrodeposition approach for the controllable synthesis of Pd-Sn ANSDs with high surface area. These synthesized Pd-Sn ANSDs exhibit high electrocatalytic activity and superior long-term cycle stability toward ethanol oxidation in alkaline media. The enhanced electrocataytic activity of Pd-Sn ANSDs may be attributed to Pd-Sn alloys, nanosheet dendrite induced promotional effect, large number of active sites on dendrite surface, large surface area, and good electrical contact with the base electrode. Because of the simple implement and high flexibility, the proposed approach can be considered as a general and powerful strategy to synthesize the alloy electrocatalysts with high surface areas and open dendritic nanostructures.

  13. Sexual experience enhances cognitive flexibility and dendritic spine density in the medial prefrontal cortex.

    Science.gov (United States)

    Glasper, Erica R; LaMarca, Elizabeth A; Bocarsly, Miriam E; Fasolino, Maria; Opendak, Maya; Gould, Elizabeth

    2015-11-01

    The medial prefrontal cortex is important for cognitive flexibility, a capability that is affected by environmental conditions and specific experiences. Aversive experience, such as chronic restraint stress, is known to impair performance on a task of cognitive flexibility, specifically attentional set-shifting, in rats. Concomitant with this performance decrement, chronic stress reduces the number of dendritic spines on pyramidal neurons in the medial prefrontal cortex. No previous studies have examined whether a rewarding experience, namely mating, affects cognitive flexibility and dendritic spines in the medial prefrontal cortex of male rats. To test this possibility, we exposed adult male rats to sexual receptive females once daily for one week, assessed attentional set-shifting performance, and then analyzed their brains for changes in dendritic spines. We found that sexual experience improved performance on extradimensional set-shifting, which is known to require the medial prefrontal cortex. Additionally, we observed increased dendritic spine density on apical and basal dendrites of pyramidal neurons in the medial prefrontal cortex, but not the orbitofrontal cortex, after sexual experience. We also found that sexual experience enhanced dendritic spine density on granule neurons of the dentate gyrus. The ventral hippocampus sends a direct projection to the medial prefrontal cortex, raising the possibility that experience-dependent changes in the hippocampus are necessary for alterations in medial prefrontal cortex structure and function. As a first attempt at investigating this, we inactivated the ventral hippocampus with the GABA agonist muscimol, after each daily bout of sexual experience to observe whether the beneficial effects on cognitive flexibility were abolished. Contrary to our hypothesis, blocking hippocampal activity after sexual experience had no impact on enhanced cognitive flexibility. Taken together, these findings indicate that sexual

  14. Enhancement of cytotoxic T lymphocyte activity by dendritic cells loaded with Tat-protein transduction domain-fused hepatitis B virus core antigen

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The protein transduction domain (PTD) of human immuno-deficiency virus-1-Tat protein has a unique potency to pen-etrate the cellular membranes. To synthesize the sequence of Tat-PTD and hepatitis B virus core antigen (HBcAg), we spliced these sequences and linked a fusion gene into the pMAL-c2x vector. The fusion proteins were purified by affin-ity chromatography and pulsed with bone marrow -derived den-dritic cells (DCs), and the transduction of recombinant pro-tein was detected by immunofluorescence antibody assay.Results showed that recombinant PTD-HBcAg could pen-etrate into DC cytoplasm while recombinant HBcAg was de-tected on the surface of cells. The percentage of DC surface molecules, such as CD80, CD86 and major histocompatibii-ity complex Ⅱ, and production of cytokine (IL-12pT0) induced by recombinant PTD-HBcAg were significantly higher than those induced by recombinant HBcAg or tumor necrosis fac-tor-α. DCs treated with PTD-HBcAg induced T cells to dif-ferentiate into specific cytotoxic T lymphocytes (CTLs) and enhanced the CTL killing response. In conclusion, the ex-pressed and purified PTD-HBcAg fusion protein could pen-etrate into cells through the plasma membrane, promote DC maturation, and enhance T cells response to generate HBcAg-specific CTLs efficiently.

  15. Active dendrites support efficient initiation of dendritic spikes in hippocampal CA3 pyramidal neurons

    OpenAIRE

    Kim, Sooyun; Guzman, Segundo J.; Hu, Hua; Jonas, Peter

    2012-01-01

    CA3 pyramidal neurons are important for memory formation and pattern completion in the hippocampal network. It is generally thought that proximal synapses from the mossy fibers activate these neurons most efficiently, whereas distal inputs from the perforant path have a weaker modulatory influence. We used confocally targeted patch-clamp recording from dendrites and axons to map the activation of rat CA3 pyramidal neurons at the subcellular level. Our results reveal two distinct dendritic dom...

  16. Sleeping dendrites: fiber-optic measurements of dendritic calcium activity in freely moving and sleeping animals

    Directory of Open Access Journals (Sweden)

    Julie Seibt

    2014-03-01

    Full Text Available Dendrites are the post-synaptic sites of most excitatory and inhibitory synapses in the brain, making them the main location of cortical information processing and synaptic plasticity. Although current hypotheses suggest a central role for sleep in proper cognitive function and brain plasticity, virtually nothing is known about changes in dendritic activity across the sleep-wake cycle and how waking experience modifies this activity. To start addressing these questions, we developed a method that allows long-term recordings of EEGs/EMG combined with in vivo cortical calcium (Ca2+ activity in freely moving and sleeping rats. We measured Ca2+ activity from populations of dendrites of layer (L 5 pyramidal neurons (n = 13 rats that we compared with Ca2+ activity from populations of neurons in L2/3 (n = 11 rats. L5 and L2/3 neurons were labelled using bolus injection of OGB1-AM or GCaMP6 (1. Ca2+ signals were detected using a fiber-optic system (cannula diameter = 400µm, transmitting the changes in fluorescence to a photodiode. Ca2+ fluctuations could then be correlated with ongoing changes in brain oscillatory activity during 5 major brain states: active wake [AW], quiet wake [QW], NREM, REM and NREM-REM transition (or intermediate state, [IS]. Our Ca2+ recordings show large transients in L5 dendrites and L2/3 neurons that oscillate predominantly at frequencies In summary, we show that this technique is successful in monitoring fluctuations in ongoing dendritic Ca2+ activity during natural brain states and allows, in principle, to combine behavioral measurement with imaging from various brain regions (e.g. deep structures in freely behaving animals. Using this method, we show that Ca2+ transients from populations of L2/3 neurons and L5 dendrites are deferentially regulated across the sleep/wake cycle, with dendritic activity being the highest during the IS sleep. Our correlation analysis suggests that specific sleep EEG activity during NREM and IS

  17. Surface-enhanced Raman scattering dendritic substrates fabricated by deposition of gold and silver on silicon.

    Science.gov (United States)

    Cheng, Mingfei; Fang, Jinghuai; Cao, Min; Jin, Yonglong

    2010-11-01

    This paper reports a study on the preparation of gold nanoparticles and silver dendrites on silicon substrates by immersion plating. Firstly, gold was deposited onto silicon wafer from HF aqueous solution containing HAuCl4. Then, the silicon wafer deposited gold was dipped into HF aqueous solution of AgNO3 to form silver coating gold film. Scanning electron microscopy reveals a uniform gold film consisted of gold nanoparticles and rough silver coating gold film containing uniform dendritic structures on silicon surface. By SERS (surface-enhanced Raman scattering) measurements, the fabricated gold and silver coating gold substrates activity toward SERS is assessed. The SERS spectra of crystal violet on the fabricated substrates reflect the different SERS activities on gold nanoparticles film and silver coating gold dendrites film. Compared with pure gold film on silicon, the film of silver coating gold dendrites film significantly increased the SERS intensity. As the fabrication process is very simple, cost-effective and reproducible, and the fabricated silver coating gold substrate is of excellent enhancement ability, spatial uniformity and good stability.

  18. Facile fabrication of dendritic silver structures and their surface enhanced Raman spectroscopic properties

    Indian Academy of Sciences (India)

    Jisheng Yang; Zhengdong Jiang

    2015-01-01

    A simple and efficient approach was developed to fabricate silver dendrites by Cu reducing Ag+ in AgNO3 solution. The growth speed, morphologies and structures of the silver dendrites strongly depend on AgNO3 concentration and reaction time. The silver dendrites were formed from nanosheets and the crystal structure is face-centered cubic. Rhodamine 6G was used as probe molecule to show that the silver dendrites have high sensitivity to surface enhanced Raman spectroscopy response.

  19. Adenosine deaminase enhances the immunogenicity of human dendritic cells from healthy and HIV-infected individuals.

    Directory of Open Access Journals (Sweden)

    Víctor Casanova

    Full Text Available 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.

  20. CD40-targeted adenoviral gene transfer to dendritic cells through the use of a novel bispecific single-chain Fv antibody enhances cytotoxic T cell activation

    NARCIS (Netherlands)

    Brandao, JG; Scheper, RJ; Lougheed, SM; Curiel, DT; Tillman, BW; Gerritsen, WR; van den Eertwegh, AJM; Pinedo, HM; Haisma, HJ; de Gruijl, TD

    2003-01-01

    Adenoviral (Ad) transduction of dendritic cells (DC) is a promising vaccination strategy. However, clinical applicability of Ad vectors is hampered by the necessity to use high titers of infectious Ad particles for efficient DC transduction. Here, we report on the production of a bacterially express

  1. Stochastic ion channel gating in dendritic neurons: morphology dependence and probabilistic synaptic activation of dendritic spikes.

    Directory of Open Access Journals (Sweden)

    Robert C Cannon

    Full Text Available Neuronal activity is mediated through changes in the probability of stochastic transitions between open and closed states of ion channels. While differences in morphology define neuronal cell types and may underlie neurological disorders, very little is known about influences of stochastic ion channel gating in neurons with complex morphology. We introduce and validate new computational tools that enable efficient generation and simulation of models containing stochastic ion channels distributed across dendritic and axonal membranes. Comparison of five morphologically distinct neuronal cell types reveals that when all simulated neurons contain identical densities of stochastic ion channels, the amplitude of stochastic membrane potential fluctuations differs between cell types and depends on sub-cellular location. For typical neurons, the amplitude of membrane potential fluctuations depends on channel kinetics as well as open probability. Using a detailed model of a hippocampal CA1 pyramidal neuron, we show that when intrinsic ion channels gate stochastically, the probability of initiation of dendritic or somatic spikes by dendritic synaptic input varies continuously between zero and one, whereas when ion channels gate deterministically, the probability is either zero or one. At physiological firing rates, stochastic gating of dendritic ion channels almost completely accounts for probabilistic somatic and dendritic spikes generated by the fully stochastic model. These results suggest that the consequences of stochastic ion channel gating differ globally between neuronal cell-types and locally between neuronal compartments. Whereas dendritic neurons are often assumed to behave deterministically, our simulations suggest that a direct consequence of stochastic gating of intrinsic ion channels is that spike output may instead be a probabilistic function of patterns of synaptic input to dendrites.

  2. Enhanced antitumor effects of tumor antigen-pulsed dendritic cells by their transfection with GM-CSF gene

    Institute of Scientific and Technical Information of China (English)

    曹雪涛; 章卫平; 马施华; 张明徽; 王建莉; 叶天星

    1997-01-01

    To investigate the biological characterization and antitumor activitites of GM-CSF gene-transfected dendritic cells, the splenic dendritic cells were infected with GM-CSF recombinant replication-deficient adenoviruses in vitro . Their enhanced expression of B7 was demonstrated by FACS analysis, and more potent stimulatory activity was confirmed by allogeneic MLR. Immunization of dendritic cells pulsed with irradiated B16 melanoma cells induced sig-nificant CTL and enabled host to resist the challenge of wild-type B16 cells. When they were transfected with GM-CSF gene subsequently, the induced CTL activity was higher, and the produced protection against B16 cell challenge and therapeutic effect on the mice with preestablished pulmonary melastases more effective. These data suggest that the dendritic cells pulsed with tumor antigen then transfected with GM-CSF gene can be used as an effective vaccine in tumor immunotherapy.

  3. Spike-triggered dendritic calcium transients depend on synaptic activity in the cricket giant interneurons.

    Science.gov (United States)

    Ogawa, Hiroto; Baba, Yoshichika; Oka, Kotaro

    2002-02-15

    The relationship between electrical activity and spike-induced Ca2+ increases in dendrites was investigated in the identified wind-sensitive giant interneurons in the cricket. We applied a high-speed Ca2+ imaging technique to the giant interneurons, and succeeded in recording the transient Ca2+ increases (Ca2+ transients) induced by a single action potential, which was evoked by presynaptic stimulus to the sensory neurons. The dendritic Ca2+ transients evoked by a pair of action potentials accumulated when spike intervals were shorter than 100 ms. The amplitude of the Ca2+ transients induced by a train of spikes depended on the number of action potentials. When stimulation pulses evoking the same numbers of action potentials were separately applied to the ipsi- or contra-lateral cercal sensory nerves, the dendritic Ca2+ transients induced by these presynaptic stimuli were different in their amplitude. Furthermore, the side of presynaptic stimulation that evoked larger Ca2+ transients depended on the location of the recorded dendritic regions. This result means that the spike-triggered Ca2+ transients in dendrites depend on postsynaptic activity. It is proposed that Ca2+ entry through voltage-dependent Ca2+ channels activated by the action potentials will be enhanced by excitatory synaptic inputs at the dendrites in the cricket giant interneurons.

  4. Linking Memories across Time via Neuronal and Dendritic Overlaps in Model Neurons with Active Dendrites

    Directory of Open Access Journals (Sweden)

    George Kastellakis

    2016-11-01

    Full Text Available Memories are believed to be stored in distributed neuronal assemblies through activity-induced changes in synaptic and intrinsic properties. However, the specific mechanisms by which different memories become associated or linked remain a mystery. Here, we develop a simplified, biophysically inspired network model that incorporates multiple plasticity processes and explains linking of information at three different levels: (1 learning of a single associative memory, (2 rescuing of a weak memory when paired with a strong one, and (3 linking of multiple memories across time. By dissecting synaptic from intrinsic plasticity and neuron-wide from dendritically restricted protein capture, the model reveals a simple, unifying principle: linked memories share synaptic clusters within the dendrites of overlapping populations of neurons. The model generates numerous experimentally testable predictions regarding the cellular and sub-cellular properties of memory engrams as well as their spatiotemporal interactions.

  5. Direction selectivity is computed by active dendritic integration in retinal ganglion cells.

    Science.gov (United States)

    Sivyer, Benjamin; Williams, Stephen R

    2013-12-01

    Active dendritic integration is thought to enrich the computational power of central neurons. However, a direct role of active dendritic processing in the execution of defined neuronal computations in intact neural networks has not been established. Here we used multi-site electrophysiological recording techniques to demonstrate that active dendritic integration underlies the computation of direction selectivity in rabbit retinal ganglion cells. Direction-selective retinal ganglion cells fire action potentials in response to visual image movement in a preferred direction. Dendritic recordings revealed that preferred-direction moving-light stimuli led to dendritic spike generation in terminal dendrites, which were further integrated and amplified as they spread through the dendritic arbor to the axon to drive action potential output. In contrast, when light bars moved in a null direction, synaptic inhibition vetoed neuronal output by directly inhibiting terminal dendritic spike initiation. Active dendritic integration therefore underlies a physiologically engaged circuit-based computation in the retina.

  6. Dendritic cells enhance UHMWPE wear particle-induced osteoclast differentiation of macrophages.

    Science.gov (United States)

    Cang, Dingwei; Guo, Kaijin; Zhao, Fengchao

    2015-10-01

    Ultra-high molecular weight polyethylene (UHMWPE) has been widely used in large joint replacement. Osteolysis induced by the UHMWPE wear particles is one of the main causes of replacement failure. This study aims to elucidate whether dendritic cells play a role in UHMWPE particle-induced osteolysis. An in vitro Raw 264.7 and DC 2.4 coculture system was employed to examine the effects of dendritic cells on the inflammatory and osteoclastogenic responses of Raw 264.7 toward UHMWPE particles. The expression of cytokines, NF-κB, and osteoclast marker genes was analyzed by ELISA, western blot, or quantitative PCR. The osteoclast differentiation was measured by TRAP staining and flow cytometry. UHMWPE particles induced Raw 264.7 cells to differentiate into osteoclasts, which was enhanced by coculturing with DC 2.4 cells. DC 2.4 cells augmented UHMWPE particle-elicited activation of NF-κB signaling, higher levels of TNF-α and MCP-1, and an increased expression of MMP-9, Calcr, and Ctsk, though DC 2.4 coculture alone did not significantly cause the aforementioned changes. These results suggest that dendritic cells, among other immune cells recruited by UHMWPE particle induced inflammation, could further exacerbate inflammation and osteolysis.

  7. Indirect Toll-like receptor 5-mediated activation of conventional dendritic cells promotes the mucosal adjuvant activity of flagellin in the respiratory tract.

    Science.gov (United States)

    Fougeron, Delphine; Van Maele, Laurye; Songhet, Pascal; Cayet, Delphine; Hot, David; Van Rooijen, Nico; Mollenkopf, Hans-Joachim; Hardt, Wolf-Dietrich; Benecke, Arndt G; Sirard, Jean-Claude

    2015-06-26

    The Toll-like receptor 5 (TLR5) agonist flagellin is an effective adjuvant for vaccination. Recently, we demonstrated that the adaptive responses stimulated by intranasal administration of flagellin and antigen were linked to TLR5 signaling in the lung epithelium. The present study sought to identify the antigen presenting cells involved in this adjuvant activity. We first found that the lung dendritic cells captured antigen very efficiently in a process independent of TLR5. However, TLR5-mediated signaling specifically enhanced the maturation of lung dendritic cells. Afterward, the number of antigen-bound and activated conventional dendritic cells (both CD11b(+) and CD103(+)) increased in the mediastinal lymph nodes in contrast to monocyte-derived dendritic cells. These data suggested that flagellin-activated lung conventional dendritic cells migrate to the draining lymph nodes. The lymph node dendritic cells, in particular CD11b(+) cells, were essential for induction of CD4 T-cell response. Lastly, neutrophils and monocytes were recruited into the lungs by flagellin administration but did not contribute to the adjuvant activity. The functional activation of conventional dendritic cells was independent of direct TLR5 signaling, thereby supporting the contribution of maturation signals produced by flagellin-stimulated airway epithelium. In conclusion, our results demonstrated that indirect TLR5-dependent stimulation of airway conventional dendritic cells is essential to flagellin's mucosal adjuvant activity.

  8. Enhanced cellular transport and drug targeting using dendritic nanostructures

    Science.gov (United States)

    Kannan, R. M.; Kolhe, Parag; Kannan, Sujatha; Lieh-Lai, Mary

    2003-03-01

    Dendrimers and hyperbranched polymers possess highly branched architectures, with a large number of controllable, tailorable, peripheral' functionalities. Since the surface chemistry of these materials can be modified with relative ease, these materials have tremendous potential in targeted drug delivery. The large density of end groups can also be tailored to create enhanced affinity to targeted cells, and can also encapsulate drugs and deliver them in a controlled manner. We are developing tailor-modified dendritic systems for drug delivery. Synthesis, drug/ligand conjugation, in vitro cellular and in vivo drug delivery, and the targeting efficiency to the cell are being studied systematically using a wide variety of experimental tools. Results on PAMAM dendrimers and polyol hyperbranched polymers suggest that: (1) These materials complex/encapsulate a large number of drug molecules and release them at tailorable rates; (2) The drug-dendrimer complex is transported very rapidly through a A549 lung epithelial cancel cell line, compared to free drug, perhaps by endocytosis. The ability of the drug-dendrimer-ligand complexes to target specific asthma and cancer cells is currently being explored using in vitro and in vivo animal models.

  9. CCR7 deficiency on dendritic cells enhances fungal clearance in a murine model of pulmonary invasive aspergillosis.

    Science.gov (United States)

    Hartigan, Adam J; Westwick, John; Jarai, Gabor; Hogaboam, Cory M

    2009-10-15

    Aspergillus fumigatus is a sporulating fungus found ubiquitously in the environment and is easily cleared from immunocompetent hosts. Invasive aspergillosis develops in immunocompromised patients, and is a leading cause of mortality in hematopoietic stem cell transplant recipients. CCR7 and its ligands, CCL19 and CCL21, are responsible for the migration of dendritic cells from sites of infection and inflammation to secondary lymphoid organs. To investigate the role of CCR7 during invasive aspergillosis, we used a well-characterized neutropenic murine model. During invasive aspergillosis, mice with a CCR7 deficiency in the hematopoietic compartment exhibited increased survival and less pulmonary injury compared with the appropriate wild-type control. Flow cytometric analysis of the chimeric mice revealed an increase in the number of dendritic cells present in the lungs of CCR7-deficient chimeras following infection with Aspergillus conidia. An adoptive transfer of dendritic cells into neutropenic mice provided a protective effect during invasive aspergillosis, which was further enhanced with the adoptive transfer of CCR7-deficient dendritic cells. Additionally, CCR7-deficient dendritic cells activated in vitro with Aspergillus conidia expressed higher TNF-alpha, CXCL10, and CXCL2 levels, indicating a more activated cellular response to the fungus. Our results suggest that the absence of CCR7 is protective during invasive aspergillosis in neutropenic mice. Collectively, these data demonstrate a potential deleterious role for CCR7 during primary immune responses directed against A. fumigatus.

  10. Exceptional methanol electro-oxidation activity by bimetallic concave and dendritic Pt-Cu nanocrystals catalysts

    Science.gov (United States)

    Wang, Ying-Xia; Zhou, Hui-Jing; Sun, Ping-Chuan; Chen, Tie-Hong

    2014-01-01

    PtCux (x = 1, 2 and 3) bimetallic nanocrystals with concave surface and dendritic morphology were prepared and used as electrocatalysts in methanol oxidation reaction (MOR) for polymer electrolyte membrane fuel cells. The bimetallic nanocrystals were synthesized via one-pot co-reduction of H2PtCl6 and Cu(acac)2 by oleylamine and polyvinyl pyrrolidone (PVP) in an autoclave at 180 °C. The concave dendritic bimetallic nanostructure consisted of a core rich in Cu and nanodendrites rich in Pt, which was formed via galvanic replacement of Cu by Pt. It was found that PVP played an important role in initiating, facilitating, and directing the replacement reaction. The electrochemical properties of the PtCux were characterized by cyclic voltammetry (CV) and chronoamperometry (CA). The concave dendritic PtCu2/C nanocrystals exhibited exceptionally high activity and strong poisoning resistance in MOR. At 0.75 V (vs. reversible hydrogen electrode, RHE) the mass activity and specific activity of PtCu2/C were 3.3 and 4.1 times higher than those of the commercial Pt/C catalysts, respectively. The enhanced catalytic activity could be attributed to the unique concave dendritic morphology of the bimetallic nanocrystals.

  11. Glycyrrhiza uralensis water extract enhances dendritic cell maturation and antitumor efficacy of HPV dendritic cell-based vaccine

    Science.gov (United States)

    Aipire, Adila; Li, Jinyu; Yuan, Pengfei; He, Jiang; Hu, Yelang; Liu, Lu; Feng, Xiaoli; Li, Yijie; Zhang, Fuchun; Yang, Jianhua; Li, Jinyao

    2017-01-01

    Licorice has been used as herbal medicine and natural sweetener. Here, we prepared Glycyrrhiza uralensis water extract (GUWE) and investigated the effect of GUWE on the maturation and function of dendritic cells (DCs) and its adjuvant effect on DC-based vaccine. We observed that GUWE dose-dependently promoted DC maturation and cytokine secretion through TLR4 signaling pathway. The capacity of DC to stimulate allogenic splenocyte proliferation was also enhanced by GUWE treatment. Compared with control group, GUWE treated DCs pulsed with human papillomavirus (HPV)-16 E6/E7 peptides significantly inhibited the tumor growth in both early and late therapeutic groups. In early therapeutic group, the frequencies of induced regulatory T cells (iTregs: CD4+CD25−Fopx3+) and CD4+ and CD8+ T cells were significantly decreased and increased, respectively. HPV-16-specific CD8+ T cell responses were significantly induced and negatively correlated with iTreg frequencies and tumor weight. These results indicated the immunoregulatory activities of licorice. PMID:28272545

  12. Travelling waves in a model of quasi-active dendrites with active spines

    Science.gov (United States)

    Timofeeva, Y.

    2010-05-01

    Dendrites, the major components of neurons, have many different types of branching structures and are involved in receiving and integrating thousands of synaptic inputs from other neurons. Dendritic spines with excitable channels can be present in large densities on the dendrites of many cells. The recently proposed Spike-Diffuse-Spike (SDS) model that is described by a system of point hot-spots (with an integrate-and-fire process) embedded throughout a passive tree has been shown to provide a reasonable caricature of a dendritic tree with supra-threshold dynamics. Interestingly, real dendrites equipped with voltage-gated ion channels can exhibit not only supra-threshold responses, but also sub-threshold dynamics. This sub-threshold resonant-like oscillatory behaviour has already been shown to be adequately described by a quasi-active membrane. In this paper we introduce a mathematical model of a branched dendritic tree based upon a generalisation of the SDS model where the active spines are assumed to be distributed along a quasi-active dendritic structure. We demonstrate how solitary and periodic travelling wave solutions can be constructed for both continuous and discrete spine distributions. In both cases the speed of such waves is calculated as a function of system parameters. We also illustrate that the model can be naturally generalised to an arbitrary branched dendritic geometry whilst remaining computationally simple. The spatio-temporal patterns of neuronal activity are shown to be significantly influenced by the properties of the quasi-active membrane. Active (sub- and supra-threshold) properties of dendrites are known to vary considerably among cell types and animal species, and this theoretical framework can be used in studying the combined role of complex dendritic morphologies and active conductances in rich neuronal dynamics.

  13. Dextromethorphan Inhibits Activations and Functions in Dendritic Cells

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    Der-Yuan Chen

    2013-01-01

    Full Text Available Dendritic cells (DCs play an important role in connecting innate and adaptive immunity. Thus, DCs have been regarded as a major target for the development of immunomodulators. In this study, we examined the effect of dextromethorphan (DXM, a common cough suppressant with a high safety profile, on the activation and function of DCs. In the presence of DXM, the LPS-induced expression of the costimulatory molecules in murine bone marrow-derived dendritic cells (BMDCs was significantly suppressed. In addition, DXM treatment reduced the production of reactive oxygen species (ROS, proinflammatory cytokines, and chemokines in maturing BMDCs that were activated by LPS. Therefore, DXM abrogated the ability of LPS-stimulated DCs to induce Ag-specific T-cell activation, as determined by their decreased proliferation and IFN-γ secretion in mixed leukocyte cultures. Moreover, the inhibition of LPS-induced MAPK activation and NF-κB translocation may contribute to the suppressive effect of DXM on BMDCs. Remarkably, DXM decreased the LPS-induced surface expression of CD80, CD83, and HLA-DR and the secretion of IL-6 and IL-12 in human monocyte-derived dendritic cells (MDDCs. These findings provide a new insight into the impact of DXM treatment on DCs and suggest that DXM has the potential to be used in treating DC-related acute and chronic diseases.

  14. Dextromethorphan Inhibits Activations and Functions in Dendritic Cells

    Science.gov (United States)

    Chen, Der-Yuan; Song, Pei-Shan; Hong, Jau-Shyong; Chu, Ching-Liang; Pan, I-Horng; Chen, Yi-Ming; Lin, Ching-Hsiung; Lin, Sheng-Hao; Lin, Chi-Chen

    2013-01-01

    Dendritic cells (DCs) play an important role in connecting innate and adaptive immunity. Thus, DCs have been regarded as a major target for the development of immunomodulators. In this study, we examined the effect of dextromethorphan (DXM), a common cough suppressant with a high safety profile, on the activation and function of DCs. In the presence of DXM, the LPS-induced expression of the costimulatory molecules in murine bone marrow-derived dendritic cells (BMDCs) was significantly suppressed. In addition, DXM treatment reduced the production of reactive oxygen species (ROS), proinflammatory cytokines, and chemokines in maturing BMDCs that were activated by LPS. Therefore, DXM abrogated the ability of LPS-stimulated DCs to induce Ag-specific T-cell activation, as determined by their decreased proliferation and IFN-γ secretion in mixed leukocyte cultures. Moreover, the inhibition of LPS-induced MAPK activation and NF-κB translocation may contribute to the suppressive effect of DXM on BMDCs. Remarkably, DXM decreased the LPS-induced surface expression of CD80, CD83, and HLA-DR and the secretion of IL-6 and IL-12 in human monocyte-derived dendritic cells (MDDCs). These findings provide a new insight into the impact of DXM treatment on DCs and suggest that DXM has the potential to be used in treating DC-related acute and chronic diseases. PMID:23781253

  15. Apolipoprotein E isoform-dependent dendritic recovery of hippocampal neurons following activation of innate immunity

    Directory of Open Access Journals (Sweden)

    Maezawa Izumi

    2006-08-01

    Full Text Available Abstract Background Innate immune activation, including a role for cluster of differentiation 14/toll-like receptor 4 co-receptors (CD14/TLR-4 co-receptors, has been implicated in paracrine damage to neurons in several neurodegenerative diseases that also display stratification of risk or clinical outcome with the common alleles of the apolipoprotein E gene (APOE: APOE2, APOE3, and APOE4. Previously, we have shown that specific stimulation of CD14/TLR-4 with lipopolysaccharide (LPS leads to greatest innate immune response by primary microglial cultures from targeted replacement (TR APOE4 mice and greatest p38MAPK-dependent paracrine damage to neurons in mixed primary cultures and hippocampal slice cultures derived from TR APOE4 mice. In contrast, TR APOE2 astrocytes had the highest NF-kappaB activity and no neurotoxicity. Here we tested the hypothesis that direct activation of CD14/TLR-4 in vivo would yield different amounts of paracrine damage to hippocampal sector CA1 pyramidal neurons in TR APOE mice. Methods We measured in vivo changes in dendrite length in hippocampal CA1 neurons using Golgi staining and determined hippocampal apoE levels by Western blot. Neurite outgrowth of cultured primary neurons in response to astrocyte conditioned medium was assessed by measuring neuron length and branch number. Results Our results showed that TR APOE4 mice had slightly but significantly shorter dendrites at 6 weeks of age. Following exposure to intracerebroventricular LPS, there was comparable loss of dendrite length at 24 hr among the three TR APOE mice. Recovery of dendrite length over the next 48 hr was greater in TR APOE2 than TR APOE3 mice, while TR APOE4 mice had failure of dendrite regeneration. Cell culture experiments indicated that the enhanced neurotrophic effect of TR APOE2 was LDL related protein-dependent. Conclusion The data indicate that the environment within TR APOE2 mouse hippocampus was most supportive of dendrite regeneration

  16. Dendritic-tumor fusion cells derived heat shock protein70-peptide complex has enhanced immunogenicity.

    Science.gov (United States)

    Zhang, Yunfei; Zhang, Yong; Chen, Jun; Liu, Yunyan; Luo, Wen

    2015-01-01

    Tumor-derived heat shock protein70-peptide complexes (HSP70.PC-Tu) have shown great promise in tumor immunotherapy due to numerous advantages. However, large-scale phase III clinical trials showed that the limited immunogenicity remained to be enhanced. In previous research, we demonstrated that heat shock protein 70-peptide complexes (HSP70.PC-Fc) derived from dendritic cell (DC)-tumor fusions exhibit enhanced immunogenicity compared with HSP70.PCs from tumor cells. However, the DCs used in our previous research were obtained from healthy donors and not from the patient population. In order to promote the clinical application of these complexes, HSP70.PC-Fc was prepared from patient-derived DC fused directly with patient-derived tumor cells in the current study. Our results showed that compared with HSP70.PC-Tu, HSP70.PC-Fc elicited much more powerful immune responses against the tumor from which the HSP70 was derived, including enhanced T cell activation, and CTL responses that were shown to be antigen specific and HLA restricted. Our results further indicated that the enhanced immunogenicity is related to the activation of CD4+ T cells and increased association with other heat shock proteins, such as HSP90. Therefore, the current study confirms the enhanced immunogenicity of HSP70.PC derived from DC-tumor fusions and may provide direct evidence promoting their future clinical use.

  17. Enhancement of basolateral amygdaloid neuronal dendritic arborization following Bacopa monniera extract treatment in adult rats

    Directory of Open Access Journals (Sweden)

    Venkata Ramana Vollala

    2011-01-01

    Full Text Available OBJECTIVE: In the ancient Indian system of medicine, Ayurveda, Bacopa monniera is classified as Medhya rasayana, which includes medicinal plants that rejuvenate intellect and memory. Here, we investigated the effect of a standardized extract of Bacopa monniera on the dendritic morphology of neurons in the basolateral amygdala, a region that is concerned with learning and memory. METHODS: The present study was conducted on 2¹/2-month-old Wistar rats. The rats were divided into 2-, 4- and 6-week treatment groups. Rats in each of these groups were further divided into 20 mg/kg, 40 mg/kg and 80 mg/kg dose groups (n = 8 for each dose. After the treatment period, treated rats and age-matched control rats were subjected to spatial learning (T-maze and passive avoidance tests. Subsequently, these rats were killed by decapitation, the brains were removed, and the amygdaloid neurons were impregnated with silver nitrate (Golgi staining. Basolateral amygdaloid neurons were traced using camera lucida, and dendritic branching points (a measure of dendritic arborization and dendritic intersections (a measure of dendritic length were quantified. These data were compared with the data from the age-matched control rats. RESULTS: The results showed an improvement in spatial learning performance and enhanced memory retention in rats treated with Bacopa monniera extract. Furthermore, a significant increase in dendritic length and the number of dendritic branching points was observed along the length of the dendrites of the basolateral amygdaloid neurons of rats treated with 40 mg/kg and 80 mg/kg of Bacopa monniera (BM for longer periods of time (i.e., 4 and 6 weeks. CONCLUSION: We conclude that constituents present in Bacopa monniera extract have neuronal dendritic growth-stimulating properties.

  18. The Gαo Activator Mastoparan-7 Promotes Dendritic Spine Formation in Hippocampal Neurons

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    Valerie T. Ramírez

    2016-01-01

    Full Text Available Mastoparan-7 (Mas-7, an analogue of the peptide mastoparan, which is derived from wasp venom, is a direct activator of Pertussis toxin- (PTX- sensitive G proteins. Mas-7 produces several biological effects in different cell types; however, little is known about how Mas-7 influences mature hippocampal neurons. We examined the specific role of Mas-7 in the development of dendritic spines, the sites of excitatory synaptic contact that are crucial for synaptic plasticity. We report here that exposure of hippocampal neurons to a low dose of Mas-7 increases dendritic spine density and spine head width in a time-dependent manner. Additionally, Mas-7 enhances postsynaptic density protein-95 (PSD-95 clustering in neurites and activates Gαo signaling, increasing the intracellular Ca2+ concentration. To define the role of signaling intermediates, we measured the levels of phosphorylated protein kinase C (PKC, c-Jun N-terminal kinase (JNK, and calcium-calmodulin dependent protein kinase IIα (CaMKIIα after Mas-7 treatment and determined that CaMKII activation is necessary for the Mas-7-dependent increase in dendritic spine density. Our results demonstrate a critical role for Gαo subunit signaling in the regulation of synapse formation.

  19. The Gαo Activator Mastoparan-7 Promotes Dendritic Spine Formation in Hippocampal Neurons

    Science.gov (United States)

    Ramírez, Valerie T.; Ramos-Fernández, Eva; Inestrosa, Nibaldo C.

    2016-01-01

    Mastoparan-7 (Mas-7), an analogue of the peptide mastoparan, which is derived from wasp venom, is a direct activator of Pertussis toxin- (PTX-) sensitive G proteins. Mas-7 produces several biological effects in different cell types; however, little is known about how Mas-7 influences mature hippocampal neurons. We examined the specific role of Mas-7 in the development of dendritic spines, the sites of excitatory synaptic contact that are crucial for synaptic plasticity. We report here that exposure of hippocampal neurons to a low dose of Mas-7 increases dendritic spine density and spine head width in a time-dependent manner. Additionally, Mas-7 enhances postsynaptic density protein-95 (PSD-95) clustering in neurites and activates Gαo signaling, increasing the intracellular Ca2+ concentration. To define the role of signaling intermediates, we measured the levels of phosphorylated protein kinase C (PKC), c-Jun N-terminal kinase (JNK), and calcium-calmodulin dependent protein kinase IIα (CaMKIIα) after Mas-7 treatment and determined that CaMKII activation is necessary for the Mas-7-dependent increase in dendritic spine density. Our results demonstrate a critical role for Gαo subunit signaling in the regulation of synapse formation. PMID:26881110

  20. Chitosan as an adjuvant-like substrate for dendritic cell culture to enhance antitumor effects.

    Science.gov (United States)

    Lin, Yong-Chong; Lou, Pei-Jen; Young, Tai-Horng

    2014-10-01

    To induce monocyte differentiation into dendritic cells (DCs) is the essential protocol for the DC-mediated cancer immunotherapy. In this study, monocytes isolated from mouse bone marrow were cultured on chitosan substrate to evaluate the effect of the chitosan culture system on the induction and tumor protection of DCs. Compared to tissue culture polystyrene (TCPS), the chitosan culture system could enhance monocyte aggregation and detachment with increased MTT reduction activity and expression of DC marker CD11c and LPS co-receptor CD14. Moreover, compared to TCPS, chitosan could enhance lipopolysaccharides (LPS)-stimulated DCs to secrete higher amount of IL-12. More importantly, vaccination of tumor lysate-pulsed DCs harvested from chitosan could increase cytotoxic T-lymphocyte (CTL) activity and showed significantly enhanced anti-tumor effect than those from TCPS. Therefore, the current study demonstrated that a protocol to culture DCs on a less-adherent chitosan substrate followed by treatment with tumor lysate has the potential in future DC-based vaccine application.

  1. Platinum nanoparticles decorated dendrite-like gold nanostructure on glassy carbon electrodes for enhancing electrocatalysis performance to glucose oxidation

    Science.gov (United States)

    Jia, Hongmei; Chang, Gang; Lei, Ming; He, Hanping; Liu, Xiong; Shu, Honghui; Xia, Tiantian; Su, Jie; He, Yunbin

    2016-10-01

    Platinum nanoparticles decorated dendrite-like gold nanostructure, bimetal composite materials on glassy carbon electrode (Pt/DGNs/GC) for enhancing electrocatalysis to glucose oxidation was designed and successfully fabricated by a facile two-step deposition method without any templates, surfactants, or stabilizers. Dendrite-like gold nanostructure was firstly deposited on the GC electrode via the potentiostatic method, and then platinum nanoparticles were decorated on the surface of gold substrate through chemical reduction deposition. X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), energy-dispersive X-ray spectroscopy (EDS) were applied to characterize the evolution of morphology and structure of the as-prepared Pt/DGNs/GC. Based on electrochemical measurements such as cyclic voltammetry, linear voltammetry and chronoamperometry, Pt/DGNs/GC exhibited significantly enhanced electrocatalytic performance to glucose oxidation compared those of pure dendrite-like Au nanoparticles in our previous report. Controlling chemical reduction deposition time, the amount of platinum nanoparticles on Au surface could be regulated, which further tuned electrocatalytic properties toward glucose oxidation. The dendrite-like gold surface partially covered by platinum nanoparticles dramatically enhanced the electrocatalytic performance for the oxidation of glucose because of excellent synergetic effects between gold and platinum species and the increased electrochemical active area from Pt nanoparticles loading. The non-enzymatic glucose biosensor based on Pt/DGNs/GC showed a rapid respond time (within 2 s), wide linear range (from 0.1 mM to 14 mM), low detection limit (0.01 mM), supernal sensitivity (275.44 μA cm-2 mM-1, R = 0.993), satisfactory reproducibility and good stability for glucose sensing. It was demonstrated that Pt/DGNs/GC could work as promising candidate for factual non-enzymatic glucose detection.

  2. Interfacial enhancement of carbon fiber composites by generation 1-3 dendritic hexamethylenetetramine functionalization

    Science.gov (United States)

    Ma, Lichun; Meng, Linghui; Fan, Dapeng; He, Jinmei; Yu, Jiali; Qi, Meiwei; Chen, Zhongwu; Huang, Yudong

    2014-03-01

    PAN-based carbon fibers (CF) were functionalized with generation (n) 1-3 dendritic hexamethylenetetramine (HMTA) (denoted as CF-Gn-HMTA, n = 1, 2 and 3) in an attempt to improve the interfacial properties between carbon fibers and epoxy matrix. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), dynamic contact angle analysis (DCA), interfacial shear strength (IFSS) and single fiber tensile testing were carried out to investigate the functionalization process of carbon fibers and the interfacial properties of the composites. Experimental results showed that generation (n) 1-3 dendritic hexamethylenetetramine was grafted uniformly on the fiber surface through the chemical reaction, and then it increased significantly the fiber surface polarity and roughness. The surface energy and IFSS of carbon fibers increased obviously after the graft CF-G3-HMTA, by 147.6% and 81%, respectively. Generation (n) 1-3 dendritic hexamethylenetetramine enhanced effectively the interfacial adhesion of the composites by improving resin wettability, increasing chemical bonding and mechanical interlocking, and the interfacial adhesion increased with dendritic generation number. Moreover, the grafting of generation (n) 1-3 dendritic hexamethylenetetramine on the carbon fiber surface improved the fiber tensile strength, which is beneficial to the in-plane properties of the resulting composites.

  3. T lymphocytes and dendritic cells are activated by the deletion of peroxiredoxin II (Prx II) gene.

    Science.gov (United States)

    Moon, Eun-Yi; Noh, Young-Wook; Han, Ying-Hao; Kim, Sun-Uk; Kim, Jin-Man; Yu, Dae-Yeul; Lim, Jong-Seok

    2006-02-15

    Peroxiredoxin II (Prx II) is a member of antioxidant enzyme family and it plays a protective role against oxidative damage. Constitutive production of endogenous reactive oxygen species was detected in spleen and bone marrow cells lacking Prx II. Here, we investigated the role of Prx II in immune responses. The total number of splenocytes (especially, the population of S-phase cells and CD3(+) T cells) was significantly higher in Prx II(-/-) mice than in wild type. Number of peripheral blood mononuclear cells (PBMCs) in Prx II(-/-) mice was also higher than wild type. Differentiation of Prx II(-/-) mouse bone marrow cells into CD11c-positive dendritic cells was greater than that of wild type. Transplantation of Prx II(-/-) bone marrow cells into wild type mice increased PBMCs in blood and bone marrow-derived dendritic cells. Prx II deletion enhances concanavalin A (ConA)-induced splenocyte proliferation and mixed lymphocyte reaction (MLR) activity of bone marrow-derived CD11c-positive dendritic cells to stimulate recipient splenocytes. Collectively, these data suggest that Prx II inhibits the immune cell responsiveness, which may be regulated by scavenging the low amount of reactive oxygen species (ROS).

  4. Ragweed subpollen particles of respirable size activate human dendritic cells.

    Directory of Open Access Journals (Sweden)

    Kitti Pazmandi

    Full Text Available Ragweed (Ambrosia artemisiifolia pollen grains, which are generally considered too large to reach the lower respiratory tract, release subpollen particles (SPPs of respirable size upon hydration. These SPPs contain allergenic proteins and functional NAD(PH oxidases. In this study, we examined whether exposure to SPPs initiates the activation of human monocyte-derived dendritic cells (moDCs. We found that treatment with freshly isolated ragweed SPPs increased the intracellular levels of reactive oxygen species (ROS in moDCs. Phagocytosis of SPPs by moDCs, as demonstrated by confocal laser-scanning microscopy, led to an up-regulation of the cell surface expression of CD40, CD80, CD86, and HLA-DQ and an increase in the production of IL-6, TNF-α, IL-8, and IL-10. Furthermore, SPP-treated moDCs had an increased capacity to stimulate the proliferation of naïve T cells. Co-culture of SPP-treated moDCs with allogeneic CD3(+ pan-T cells resulted in increased secretion of IFN-γ and IL-17 by T cells of both allergic and non-allergic subjects, but induced the production of IL-4 exclusively from the T cells of allergic individuals. Addition of exogenous NADPH further increased, while heat-inactivation or pre-treatment with diphenyleneiodonium (DPI, an inhibitor of NADPH oxidases, strongly diminished, the ability of SPPs to induce phenotypic and functional changes in moDCs, indicating that these processes were mediated, at least partly, by the intrinsic NAD(PH oxidase activity of SPPs. Collectively, our data suggest that inhaled ragweed SPPs are fully capable of activating dendritic cells (DCs in the airways and SPPs' NAD(PH oxidase activity is involved in initiation of adaptive immune responses against innocuous pollen proteins.

  5. Interfacial enhancement of carbon fiber composites by generation 1–3 dendritic hexamethylenetetramine functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Lichun; Meng, Linghui [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Fan, Dapeng [College of Material and Chemical Engineering, Heilongjiang Institute of Technology (China); He, Jinmei; Yu, Jiali; Qi, Meiwei; Chen, Zhongwu [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Huang, Yudong, E-mail: ydhuang.hit1@yahoo.com.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China)

    2014-03-01

    Highlights: • A new chemical grafting method for carbon fibers was proposed. • The oxidation system adopts K{sub 2}S{sub 2}O{sub 8} and AgNO{sub 3}. • The interfacial shear strength (IFSS) of carbon fiber increased by 61%, and the interfacial adhesion increased with dendritic generation number. • The tensile strength of carbon fiber does not decrease distinctly. • The treatment conditions are mild and convenient. - Abstract: PAN-based carbon fibers (CF) were functionalized with generation (n) 1–3 dendritic hexamethylenetetramine (HMTA) (denoted as CF-G{sub n}-HMTA, n = 1, 2 and 3) in an attempt to improve the interfacial properties between carbon fibers and epoxy matrix. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), dynamic contact angle analysis (DCA), interfacial shear strength (IFSS) and single fiber tensile testing were carried out to investigate the functionalization process of carbon fibers and the interfacial properties of the composites. Experimental results showed that generation (n) 1–3 dendritic hexamethylenetetramine was grafted uniformly on the fiber surface through the chemical reaction, and then it increased significantly the fiber surface polarity and roughness. The surface energy and IFSS of carbon fibers increased obviously after the graft CF-G{sub 3}-HMTA, by 147.6% and 81%, respectively. Generation (n) 1–3 dendritic hexamethylenetetramine enhanced effectively the interfacial adhesion of the composites by improving resin wettability, increasing chemical bonding and mechanical interlocking, and the interfacial adhesion increased with dendritic generation number. Moreover, the grafting of generation (n) 1–3 dendritic hexamethylenetetramine on the carbon fiber surface improved the fiber tensile strength, which is beneficial to the in-plane properties of the resulting composites.

  6. DMPD: Proximal effects of Toll-like receptor activation in dendritic cells. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17142025 Proximal effects of Toll-like receptor activation in dendritic cells. Watt...) (.svg) (.html) (.csml) Show Proximal effects of Toll-like receptor activation in dendritic cells. PubmedID... 17142025 Title Proximal effects of Toll-like receptor activation in dendritic ce

  7. Design of phosphorylated dendritic architectures to promote human monocyte activation.

    Science.gov (United States)

    Poupot, Mary; Griffe, Laurent; Marchand, Patrice; Maraval, Alexandrine; Rolland, Olivier; Martinet, Ludovic; L'Faqihi-Olive, Fatima-Ezzahra; Turrin, Cédric-Olivier; Caminade, Anne-Marie; Fournié, Jean-Jacques; Majoral, Jean-Pierre; Poupot, Rémy

    2006-11-01

    As first defensive line, monocytes are a pivotal cell population of innate immunity. Monocyte activation can be relevant to a range of immune conditions and responses. Here we present new insights into the activation of monocytes by a series of phosphonic acid-terminated, phosphorus-containing dendrimers. Various dendritic or subdendritic structures were synthesized and tested, revealing the basic structural requirements for monocyte activation. We showed that multivalent character and phosphonic acid capping of dendrimers are crucial for monocyte targeting and activation. Confocal videomicroscopy showed that a fluorescein-tagged dendrimer binds to isolated monocytes and gets internalized within a few seconds. We also found that dendrimers follow the phagolysosomial route during internalization by monocytes. Finally, we performed fluorescence resonance energy transfer (FRET) experiments between a specifically designed fluorescent dendrimer and phycoerythrin-coupled antibodies. We showed that the typical innate Toll-like receptor (TLR)-2 is clearly involved, but not alone, in the sensing of dendrimers by monocytes. In conclusion, phosphorus-containing dendrimers appear as precisely tunable nanobiotools able to target and activate human innate immunity and thus prove to be good candidates to develop new drugs for immunotherapies.

  8. Brain-derived neurotrophic factor mediates activity-dependent dendritic growth in nonpyramidal neocortical interneurons in developing organotypic cultures.

    Science.gov (United States)

    Jin, Xiaoming; Hu, Hang; Mathers, Peter H; Agmon, Ariel

    2003-07-02

    Brain-derived neurotrophic factor (BDNF) promotes postnatal maturation of GABAergic inhibition in the cerebral and cerebellar cortices, and its expression and release are enhanced by neuronal activity, suggesting that it acts in a feedback manner to maintain a balance between excitation and inhibition during development. BDNF promotes differentiation of cerebellar, hippocampal, and neostriatal inhibitory neurons, but its effects on the dendritic development of neocortical inhibitory interneurons remain unknown. Here, we show that BDNF mediates depolarization-induced dendritic growth and branching in neocortical interneurons. To visualize inhibitory interneurons, we biolistically transfected organotypic cortical slice cultures from neonatal mice with green fluorescent protein (GFP) driven by the glutamic acid decarboxylase (GAD)67 promoter. Nearly all GAD67-GFP-expressing neurons were nonpyramidal, many contained GABA, and some expressed markers of neurochemically defined GABAergic subtypes, indicating that GAD67-GFP-expressing neurons were GABAergic. We traced dendritic trees from confocal images of the same GAD67-GFP-expressing neurons before and after a 5 d growth period, and quantified the change in total dendritic length (TDL) and total dendritic branch points (TDBPs) for each neuron. GAD67-GFP-expressing neurons growing in control medium exhibited a 20% increase in TDL, but in 200 ng/ml BDNF or 10 mm KCl, this increase nearly doubled and was accompanied by a significant increase in TDBPs. Blocking action potentials with TTX did not prevent the BDNF-induced growth, but antibodies against BDNF blocked the growth-promoting effect of KCl. We conclude that BDNF, released by neocortical pyramidal neurons in response to depolarization, enhances dendritic growth and branching in nearby inhibitory interneurons.

  9. Mannoproteins from Cryptococcus neoformans promote dendritic cell maturation and activation.

    Science.gov (United States)

    Pietrella, Donatella; Corbucci, Cristina; Perito, Stefano; Bistoni, Giovanni; Vecchiarelli, Anna

    2005-02-01

    Our previous data show that mannoproteins (MPs) from Cryptococcus neoformans are able to induce protective responses against both C. neoformans and Candida albicans. Here we provide evidence that MPs foster maturation and activation of human dendritic cells (DCs). Maturation was evaluated by the ability of MPs to facilitate expression of costimulatory molecules such as CD40, CD86, CD83, and major histocompatibility complex classes I and II and to inhibit receptors such as CD14, CD16, and CD32. Activation of DCs was measured by the capacity of MPs to promote interleukin-12 and tumor necrosis factor alpha secretion. DC-induced maturation and interleukin-12 induction are largely mediated by engagement of mannose receptors and presume MP internalization and degradation. DC activation leads to IkappaBalpha phosphorylation, which is necessary for nuclear factor kappaB transmigration into the nucleus. MP-loaded DCs are efficient stimulators of T cells and show a remarkable capacity to promote CD4 and CD8 proliferation. In conclusion, we have evidenced a novel regulatory role of MPs that promotes their candidacy as a vaccine against fungi.

  10. Silencing invariant chains of dendritic cells enhances anti-tumor immunity using small-interfering RNA

    Institute of Scientific and Technical Information of China (English)

    KE Shan; CHEN Xue-hua; ZHU Zheng-gang; LI Jian-fang; YU Bei-qin; GU Qin-long; LIU Bing-ya

    2010-01-01

    Background Genetic modification of dendritic cells (DCs) has been used as an effective approach to enhance anti-tumor immunity. RNA interference (RNAi), which can cause the degradation of any RNA in a sequence-specific manner, is a post-transcriptional gene silencing mechanism. In this study, small-interfering RNA (siRNA) specific for the Ii gene was transfected into DCs, and the anti-tumor immunity of Ii-silenced DCs was assessed.Methods The silencing effect of siRNA was evaluated by Western blotting and real-time PCR analyses. In vitro cytotoxic activity of T cells was evaluated using a Cytotox 96(R) non-radioactive cytotoxicity assay kit. The time to tumor onset and the tumor volumes were used as reliable indices to assess the anti-tumor immunity in vivo. To further examine the mechanisms underlying the anti-tumor immunity, flow cytometry analysis was used.Results The Ii expression of DCs was significantly reduced after Ii siRNA transfection. Significant in vitro anti-tumor ability was exhibited when DCs were co-transfected with Ii siRNA plus endogenous tumor antigen (P <0.05). Furthermore,tumor growth was greatly inhibited when mice were immunized with DCs transfected with Ii siRNA plus tumor antigen prior to or subsequent to tumor implantation. Flow cytometry analysis in vitro and in vivo indicated that both CD4+ and CD8+ T cells were significantly activated in the Ii siRNA group (P <0.05).Conclusion Silencing of the Ii gene of DCs may offer a potential approach to enhance DC-based anti-tumor immunity.

  11. Platinum nanoparticles decorated dendrite-like gold nanostructure on glassy carbon electrodes for enhancing electrocatalysis performance to glucose oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Hongmei [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science and Engineering, Hubei University, No. 368 Youyi Avenue, Wuchang, Wuhan 430062 (China); Chang, Gang, E-mail: changgang@hubu.edu.cn [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science and Engineering, Hubei University, No. 368 Youyi Avenue, Wuchang, Wuhan 430062 (China); Lei, Ming [State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); He, Hanping [College of Chemistry and Chemical Engineer, Hubei University, Youyi Road 368, Wuchang, Wuhan, Hubei 430062 (China); Liu, Xiong; Shu, Honghui; Xia, Tiantian; Su, Jie [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science and Engineering, Hubei University, No. 368 Youyi Avenue, Wuchang, Wuhan 430062 (China); He, Yunbin, E-mail: ybhe@hubu.edu.cn [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science and Engineering, Hubei University, No. 368 Youyi Avenue, Wuchang, Wuhan 430062 (China)

    2016-10-30

    Highlights: • Pt/DGNs/GC composites were obtained via a clean and facile method without any templates, surfactants, or stabilizers. • Controlling chemical reduction deposition time, the amount of platinum nanoparticles on Au surface could be regulated, which further tuned electrocatalytic properties toward glucose oxidation. • The obtained Pt/DGNs/GC composites with high electrochemical active surface area (ECSA) show superior electrocatalytic activity to glucose. • The sensor based on Pt/DGNs/GC exhibited excellent sensitivity, selectivity and stability for nonenzymatic glucose detection. - Abstract: Platinum nanoparticles decorated dendrite-like gold nanostructure, bimetal composite materials on glassy carbon electrode (Pt/DGNs/GC) for enhancing electrocatalysis to glucose oxidation was designed and successfully fabricated by a facile two-step deposition method without any templates, surfactants, or stabilizers. Dendrite-like gold nanostructure was firstly deposited on the GC electrode via the potentiostatic method, and then platinum nanoparticles were decorated on the surface of gold substrate through chemical reduction deposition. X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), energy-dispersive X-ray spectroscopy (EDS) were applied to characterize the evolution of morphology and structure of the as-prepared Pt/DGNs/GC. Based on electrochemical measurements such as cyclic voltammetry, linear voltammetry and chronoamperometry, Pt/DGNs/GC exhibited significantly enhanced electrocatalytic performance to glucose oxidation compared those of pure dendrite-like Au nanoparticles in our previous report. Controlling chemical reduction deposition time, the amount of platinum nanoparticles on Au surface could be regulated, which further tuned electrocatalytic properties toward glucose oxidation. The dendrite-like gold surface partially covered by platinum nanoparticles dramatically enhanced the electrocatalytic performance for the

  12. An Engineered Herpesvirus Activates Dendritic Cells and Induces Protective Immunity

    Science.gov (United States)

    Ma, Yijie; Chen, Min; Jin, Huali; Prabhakar, Bellur S.; Valyi-Nagy, Tibor; He, Bin

    2017-01-01

    Herpes simplex viruses (HSV) are human pathogens that switch between lytic and latent infection. While attenuated HSV is explored for vaccine, the underlying event remains poorly defined. Here we report that recombinant HSV-1 with a mutation in the γ134.5 protein, a virulence factor, stimulates dendritic cell (DC) maturation which is dependent on TANK-binding kinase 1 (TBK1). When exposed to CD11+ DCs, the mutant virus that lacks the amino terminus of γ134.5 undergoes temporal replication without production of infectious virus. Mechanistically, this leads to sequential phosphorylation of interferon regulatory factor 3 (IRF3) and p65/RelA. In correlation, DCs up-regulate the expression of co-stimulatory molecules and cytokines. However, selective inhibition of TBK1 precludes phosphorylation of IRF3 and subsequent DC activation by the γ134.5 mutant. Herein, the γ134.5 mutant is immune-stimulatory and non-destructive to DCs. Remarkably, upon immunization the γ134.5 mutant induces protection against lethal challenge by the wild type virus, indicative of its vaccine potential. Furthermore, CD11+ DCs primed by the γ134.5 mutant in vivo mediate protection upon adoptive transfer. These results suggest that activation of TBK1 by engineered HSV is crucial for DC maturation, which may contribute to protective immunity. PMID:28150813

  13. Equine dendritic cells generated with horse serum have enhanced functionality in comparison to dendritic cells generated with fetal bovine serum

    OpenAIRE

    Ziegler, A; Everett, H.; Hamza, E; Garbani, M; Gerber, V.; Marti, E; Steinbach, F

    2016-01-01

    Background: Dendritic cells are professional antigen-presenting cells that play an essential role in the initiation and modulation of T cell responses. They have been studied widely for their potential clinical applications, but for clinical use to be successful, alternatives to xenogeneic substances like fetal bovine serum (FBS) in cell culture need to be found. Protocols for the generation of dendritic cells ex vivo from monocytes are well established for several species, including horses. ...

  14. Brucella β 1,2 cyclic glucan is an activator of human and mouse dendritic cells.

    Directory of Open Access Journals (Sweden)

    Anna Martirosyan

    Full Text Available Bacterial cyclic glucans are glucose polymers that concentrate within the periplasm of alpha-proteobacteria. These molecules are necessary to maintain the homeostasis of the cell envelope by contributing to the osmolarity of Gram negative bacteria. Here, we demonstrate that Brucella β 1,2 cyclic glucans are potent activators of human and mouse dendritic cells. Dendritic cells activation by Brucella β 1,2 cyclic glucans requires TLR4, MyD88 and TRIF, but not CD14. The Brucella cyclic glucans showed neither toxicity nor immunogenicity compared to LPS and triggered antigen-specific CD8(+ T cell responses in vivo. These cyclic glucans also enhanced antigen-specific CD4(+ and CD8(+ T cell responses including cross-presentation by different human DC subsets. Brucella β 1,2 cyclic glucans increased the memory CD4(+ T cell responses of blood mononuclear cells exposed to recombinant fusion proteins composed of anti-CD40 antibody and antigens from both hepatitis C virus and Mycobacterium tuberculosis. Thus cyclic glucans represent a new class of adjuvants, which might contribute to the development of effective antimicrobial therapies.

  15. Statins decrease dendritic arborization in rat sympathetic neurons by blocking RhoA activation

    OpenAIRE

    Kim, Woo-Yang; Gonsiorek, Eugene A.; Barnhart, Chris; Davare, Monika A.; Engebose, Abby J.; Lauridsen, Holly; Bruun, Donald; Lesiak, Adam; Wayman, Gary; Bucelli, Robert; Higgins, Dennis; Lein, Pamela J.

    2009-01-01

    Clinical and experimental evidence suggest that statins decrease sympathetic activity, but whether peripheral mechanisms involving direct actions on post-ganglionic sympathetic neurons contribute to this effect is not known. Because tonic activity of these neurons is directly correlated with the size of their dendritic arbor, we tested the hypothesis that statins decrease dendritic arborization in sympathetic neurons. Oral administration of atorvastatin (20 mg/kg/day for 7 days) significantly...

  16. Dendritic calcium activity precedes inspiratory bursts in preBotzinger complex neurons

    DEFF Research Database (Denmark)

    Del Negro, Christopher A; Hayes, John A; Rekling, Jens C

    2011-01-01

    Medullary interneurons of the preBötzinger complex assemble excitatory networks that produce inspiratory-related neural rhythms, but the importance of somatodendritic conductances in rhythm generation is still incompletely understood. Synaptic input may cause Ca(2+) accumulation postsynaptically...... to evoke a Ca(2+)-activated inward current that contributes to inspiratory burst generation. We measured Ca(2+) transients by two-photon imaging dendrites while recording neuronal somata electrophysiologically. Dendritic Ca(2+) accumulation frequently precedes inspiratory bursts, particularly at recording...... suggest that dendritic Ca(2+) activates an inward current to electrotonically depolarize the soma, rather than propagate as a regenerative Ca(2+) wave. These data provide new evidence that respiratory rhythmogenesis may depend on dendritic burst-generating conductances activated in the context of network...

  17. Autocrine interferon priming in macrophages but not dendritic cells results in enhanced cytokine and chemokine production after coronavirus infection.

    Science.gov (United States)

    Zhou, Haixia; Zhao, Jincun; Perlman, Stanley

    2010-10-19

    Coronaviruses efficiently inhibit interferon (IFN) induction in nonhematopoietic cells and conventional dendritic cells (cDC). However, IFN is produced in infected macrophages, microglia, and plasmacytoid dendritic cells (pDC). To begin to understand why IFN is produced in infected macrophages, we infected bone marrow-derived macrophages (BMM) and as a control, bone marrow-derived DC (BMDC) with the coronavirus mouse hepatitis virus (MHV). As expected, BMM but not BMDC expressed type I IFN. IFN production in infected BMM was nearly completely dependent on signaling through the alpha/beta interferon (IFN-α/β) receptor (IFNAR). Several IFN-dependent cytokines and chemokines showed the same expression pattern, with enhanced production in BMM compared to BMDC and dependence upon signaling through the IFNAR. Exogenous IFN enhanced IFN-dependent gene expression in BMM at early times after infection and in BMDC at all times after infection but did not stimulate expression of molecules that signal through myeloid differentiation factor 88 (MyD88), such as tumor necrosis factor (TNF). Collectively, our results show that IFN is produced at early times postinfection (p.i.) in MHV-infected BMM, but not in BMDC, and primes expression of IFN and IFN-responsive genes. Further, our results also show that BMM are generally more responsive to MHV infection, since MyD88-dependent pathways are also activated to a greater extent in these cells than in BMDC.

  18. Haemophilus ducreyi partially activates human myeloid dendritic cells.

    Science.gov (United States)

    Banks, Keith E; Humphreys, Tricia L; Li, Wei; Katz, Barry P; Wilkes, David S; Spinola, Stanley M

    2007-12-01

    Dendritic cells (DC) orchestrate innate and adaptive immune responses to bacteria. How Haemophilus ducreyi, which causes genital ulcers and regional lymphadenitis, interacts with DC is unknown. H. ducreyi evades uptake by polymorphonuclear leukocyte and macrophage-like cell lines by secreting LspA1 and LspA2. Many H. ducreyi strains express cytolethal distending toxin (CDT), and recombinant CDT causes apoptosis of DC in vitro. Here, we examined interactions between DC and H. ducreyi 35000HP, which produces LspA1, LspA2, and CDT. In human volunteers infected with 35000HP, the ratio of myeloid DC to plasmacytoid DC was 2.8:1 in lesions, compared to a ratio of 1:1 in peripheral blood. Using myeloid DC derived from monocytes as surrogates for lesional DC, we found that DC infected with 35000HP remained as viable as uninfected DC for up to 48 h. Gentamicin protection and confocal microscopy assays demonstrated that DC ingested and killed 35000HP, but killing was incomplete at 48 h. The expression of LspA1 and LspA2 did not inhibit the uptake of H. ducreyi, despite inactivating Src kinases. Infection of DC with live 35000HP caused less cell surface marker activation than infection with heat-killed 35000HP and lipopolysaccharide (LPS) and inhibited maturation by LPS. However, infection of DC with live bacteria caused the secretion of significantly higher levels of interleukin-6 and tumor necrosis factor alpha than infection with heat-killed bacteria and LPS. The survival of H. ducreyi in DC may provide a mechanism by which the organism traffics to lymph nodes. Partial activation of DC may abrogate the establishment of a full Th1 response and an environment that promotes phagocytosis.

  19. Residual endotoxin contaminations in recombinant proteins are sufficient to activate human CD1c+ dendritic cells.

    Science.gov (United States)

    Schwarz, Harald; Schmittner, Maria; Duschl, Albert; Horejs-Hoeck, Jutta

    2014-01-01

    Many commercially available recombinant proteins are produced in Escherichia coli, and most suppliers guarantee contamination levels of less than 1 endotoxin unit (EU). When we analysed commercially available proteins for their endotoxin content, we found contamination levels in the same range as generally stated in the data sheets, but also some that were higher. To analyse whether these low levels of contamination have an effect on immune cells, we stimulated the monocytic cell line THP-1, primary human monocytes, in vitro differentiated human monocyte-derived dendritic cells, and primary human CD1c+ dendritic cells (DCs) with very low concentrations of lipopolysaccharide (LPS; ranging from 0.002-2 ng/ml). We show that CD1c+ DCs especially can be activated by minimal amounts of LPS, equivalent to the levels of endotoxin contamination we detected in some commercially available proteins. Notably, the enhanced endotoxin sensitivity of CD1c+ DCs was closely correlated with high CD14 expression levels observed in CD1c+ DCs that had been maintained in cell culture medium for 24 hours. When working with cells that are particularly sensitive to LPS, even low endotoxin contamination may generate erroneous data. We therefore recommend that recombinant proteins be thoroughly screened for endotoxin contamination using the limulus amebocyte lysate test, fluorescence-based assays, or a luciferase based NF-κB reporter assay involving highly LPS-sensitive cells overexpressing TLR4, MD-2 and CD14.

  20. Dendritic morphology, synaptic transmission, and activity of mature granule cells born following pilocarpine-induced status epilepticus in the rat

    Directory of Open Access Journals (Sweden)

    Fei eGao

    2015-10-01

    Full Text Available To understand the potential role of enhanced hippocampal neurogenesis after pilocarpine-induced status epilepticus (SE in the development of epilepsy, we quantitatively analyzed the geometry of apical dendrites, synaptic transmission, and activation levels of normotopically distributed mature newborn granule cells in the rat.SE in male Sprague-Dawley rats lasting for more than 2 hours was induced by an intraperitoneal injection of pilocarpine. The complexity, spine density, miniature post-synaptic currents, and activity-regulated cytoskeleton-associated protein (Arc expression of granule cells born five days after SE were studied at least 10 weeks after CAG-GFP retroviral vector-mediated labeling.Mature granule cells born after SE had dendritic complexity similar to that of granule cells born naturally, but with denser mushroom-like spines in dendritic segments located in the outer molecular layer. Miniature inhibitory post-synaptic currents (mIPSCs were similar between the controls and rats subjected to SE; however, smaller miniature excitatory post-synaptic current (mEPSC amplitude with a trend toward less frequent was found in mature granule cells born after SE. After maturation, granule cells born after SE did not show denser Arc expression in the resting condition or after being activated by transient seizure activity than vicinal GFP-unlabeled granule cells.Thus our results suggest that normotopic granule cells born after pilocarpine-induced SE are no more active when mature than age-matched, naturally born granule cells.

  1. Lymphotactin enhances the in-vitro immune efficacy of dendritoma formed by dendritic cells and mouse hepatocellular carcinoma cells

    Institute of Scientific and Technical Information of China (English)

    张浩; 蒋国平; 郑树森; 吴丽花; 朱峰; 杨振林

    2004-01-01

    Objective: To investigate the in-vitro antitumor immune responses of dendritoma formed by mouse hepatocellular carcinoma (HCC) cells and lymphotactin (Lptn) gene modified dendritic cells (DCs). Method: DCs prepared from mouse bone marrow were genetically modified by lymphotactin adenovirus, and fused with H22 cells by polyethylene glycol (PEG). RT-PCR and ELISA were employed to identify lymphotactin expression at mRNA and protein level. Cell phenotypes and fusion efficiency was detected by FACS. The stimulatory effect of DC on T cells was detected by mixed lymphocyte reaction. The cytotoxicity activity against H22 cells was assayed by LDH method. Results: Lymphotactin could be efficiently expressed by DCLptn/H22 hybridoma. DCLptn/H22 cells could induce potent T cell proliferation effect and generate strong cytotoxic T lymphocyte (CTL) reaction against allogenic H22 cells. Conclusion: Lymphotactin genetic modification could enhance the in vitro immune activity of the dendritoma.

  2. Conditional self-discrimination enhances dendritic spine number and dendritic length at prefrontal cortex and hippocampal neurons of rats.

    Science.gov (United States)

    Penagos-Corzo, Julio C; Bonilla, Andrea; Rodríguez-Moreno, Antonio; Flores, Gonzalo; Negrete-Díaz, José V

    2015-11-01

    We studied conditional self-discrimination (CSD) in rats and compared the neuronal cytoarchitecture of untrained animals and rats that were trained in self-discrimination. For this purpose, we used thirty 10-week-old male rats were randomized into three groups: one control group and two conditioning groups: a comparison group (associative learning) and an experimental group (self-discrimination). At the end of the conditioning process, the experimental group managed to discriminate their own state of thirst. After the conditioning process, dendritic morphological changes in the pyramidal neurons of the prefrontal cortex and CA1 region of the dorsal hippocampus were evaluated using Golgi-Cox stain method and then analyzed by the Sholl method. Differences were found in total dendritic length and spine density. Animals trained in self-discrimination showed an increase in the dendritic length and the number of dendritic spines of neurons of the prefrontal cortex and CA1 region of the dorsal hippocampus. Our data suggest that conditional self-discrimination improves the connectivity of the prefrontal cortex and dorsal CA1, which has implications for memory and learning processes.

  3. Mammal-derived respiratory lipocalin allergens do not exhibit dendritic cell-activating capacity.

    Science.gov (United States)

    Parviainen, S; Kinnunen, T; Rytkönen-Nissinen, M; Nieminen, A; Liukko, A; Virtanen, T

    2013-03-01

    Most mammal-derived respiratory allergens belong to the lipocalin family of proteins. Determinants of their allergenic capacity are still unknown. Innate immune cells, in particular dendritic cells, have been shown to be involved in the allergenicity of some proteins. As recognition by dendritic cells is one of the few plausible mechanisms for the allergenicity of proteins, we wanted to investigate their role in the allergenicity of lipocalin allergens. Therefore, we first incubated human monocyte-derived dendritic cells with immunologically functional recombinant allergens mouse Mus m 1, dog Can f 1 and 2, cow Bos d 2, horse Equ c 1 and natural Bos d 2. Then, the surface marker expression and cytokine production of dendritic cells and their capacity to promote T cell proliferation and Th2 immune deviation in naïve CD4(+) T cells were examined in vitro. We found that near to endotoxin-free lipocalin allergens had no effect on the activation, allostimulatory capacity or cytokine production of dendritic cells. The dendritic cells could not induce immune deviation in naïve CD4(+) T cells. In contrast, lipopolysaccharide activated the dendritic cells efficiently. However, lipocalin allergens were not able to modify the lipopolysaccharide-induced responses. We conclude that an important group of mammal-derived respiratory allergens, lipocalins, appear not to be able to activate dendritic cells, a major component involved in the allergenicity of some proteins. It is conceivable that this incapacity of lipocalin allergens to arouse innate immunity may be associated with their poor capacity to induce a strong T cell response, verified in several studies.

  4. Recognition of enteroinvasive Escherichia coli and Shigella flexneri by dendritic cells: distinct dendritic cell activation states

    Directory of Open Access Journals (Sweden)

    Ana Carolina Ramos Moreno

    2012-02-01

    Full Text Available The innate and adaptive immune responses of dendritic cells (DCs to enteroinvasive Escherichia coli (EIEC infection were compared with DC responses to Shigella flexneri infection. EIEC triggered DCs to produce interleukin (IL-10, IL-12 and tumour necrosis factor (TNF-α, whereas S. flexneri induced only the production of TNF-α. Unlike S. flexneri, EIEC strongly increased the expression of toll like receptor (TLR-4 and TLR-5 in DCs and diminished the expression of co-stimulatory molecules that may cooperate to inhibit CD4+ T-lymphocyte proliferation. The inflammation elicited by EIEC seems to be related to innate immunity both because of the aforementioned results and because only EIEC were able to stimulate DC transmigration across polarised Caco-2 cell monolayers, a mechanism likely to be associated with the secretion of CC chemokine ligands (CCL20 and TNF-α. Understanding intestinal DC biology is critical to unravelling the infection strategies of EIEC and may aid in the design of treatments for infectious diseases.

  5. Enhanced lentiviral transduction of monocyte-derived dendritic cells in the presence of conditioned medium from dying monocytes.

    Science.gov (United States)

    Masurier, C; Boutin, S; Veron, P; Bernard, J; Danos, O; Davoust, J

    2007-02-01

    Lentiviral vectors (LVs) are attractive vehicles for the transduction of human dendritic cells (DCs) in order to mobilize their endogenous antigen presentation pathways. We analyzed here how to improve the efficiency of LV transduction, which we performed at the initial stages of the differentiation of purified monocytes into dendritic cells (Mo-DCs). Using LVs pseudotyped with the vesicular stomatitis virus envelope G glycoprotein (VSV-G), we found that a conditioned medium derived from dying monocytes (MCM) improved by 2- to 10- fold the proportion of transduced Mo-DCs. This enhanced transduction efficiency requires the presence of MCM during the initial stage of LV transduction and does not affect the phenotype and antigen presentation function of terminally differentiated Mo-DCs. Importantly, we found that MCM derived from a human acute monocytic leukemia cell line, THP-1, was equally effective. The MCM activity was heat stable (56 degrees C) and was present in the soluble fraction after high-speed centrifugation. Altogether our results show that a soluble factor present in dying monocyte cultures can replace advantageously facilitating agents such as Polybrene, to achieve high LV transductions levels. This protocol can be performed with autologous monocytes and is therefore applicable in clinical settings.

  6. Cryptococcus neoformans activates bone marrow-derived conventional dendritic cells rather than plasmacytoid dendritic cells and down-regulates macrophages.

    Science.gov (United States)

    Siegemund, Sabine; Alber, Gottfried

    2008-04-01

    Induction of IL-12 and IL-23 is essential for protective immunity against Cryptococcusneoformans. The contribution of dendritic cells vs. macrophages to IL-12/23 production in response to C. neoformans infection is unclear. Activation of conventional bone marrow-derived dendritic cells (BMDC), plasmacytoid BMDC, and bone marrow-derived macrophages (BMMPhi) was assessed by analyzing cytokine responses and the expression of MHC-II, CD86, and CD80 in each cell type. Cryptococcus neoformans induced the release of IL-12/23p40 by BMDC, but not by BMMPhi, in a TLR2- and TLR4-independent but MyD88-dependent manner. Conventional BMDC rather than plasmacytoid BMDC up-regulated MHC-II and CD86, while BMMPhi down-regulated MHC-II and CD86 in response to C. neoformans. The up-regulation of MHC-II and CD86 on BMDC required MyD88. Our data point to conventional DC as critical IL-12/23-producing antigen-presenting cells during cryptococcosis.

  7. Effects of active conductance distribution over dendrites on the synaptic integration in an identified nonspiking interneuron.

    Directory of Open Access Journals (Sweden)

    Akira Takashima

    Full Text Available The synaptic integration in individual central neuron is critically affected by how active conductances are distributed over dendrites. It has been well known that the dendrites of central neurons are richly endowed with voltage- and ligand-regulated ion conductances. Nonspiking interneurons (NSIs, almost exclusively characteristic to arthropod central nervous systems, do not generate action potentials and hence lack voltage-regulated sodium channels, yet having a variety of voltage-regulated potassium conductances on their dendritic membrane including the one similar to the delayed-rectifier type potassium conductance. It remains unknown, however, how the active conductances are distributed over dendrites and how the synaptic integration is affected by those conductances in NSIs and other invertebrate neurons where the cell body is not included in the signal pathway from input synapses to output sites. In the present study, we quantitatively investigated the functional significance of active conductance distribution pattern in the spatio-temporal spread of synaptic potentials over dendrites of an identified NSI in the crayfish central nervous system by computer simulation. We systematically changed the distribution pattern of active conductances in the neuron's multicompartment model and examined how the synaptic potential waveform was affected by each distribution pattern. It was revealed that specific patterns of nonuniform distribution of potassium conductances were consistent, while other patterns were not, with the waveform of compound synaptic potentials recorded physiologically in the major input-output pathway of the cell, suggesting that the possibility of nonuniform distribution of potassium conductances over the dendrite cannot be excluded as well as the possibility of uniform distribution. Local synaptic circuits involving input and output synapses on the same branch or on the same side were found to be potentially affected under

  8. Liquid state machine with dendritically enhanced readout for low-power, neuromorphic VLSI implementations.

    Science.gov (United States)

    Roy, Subhrajit; Banerjee, Amitava; Basu, Arindam

    2014-10-01

    In this paper, we describe a new neuro-inspired, hardware-friendly readout stage for the liquid state machine (LSM), a popular model for reservoir computing. Compared to the parallel perceptron architecture trained by the p-delta algorithm, which is the state of the art in terms of performance of readout stages, our readout architecture and learning algorithm can attain better performance with significantly less synaptic resources making it attractive for VLSI implementation. Inspired by the nonlinear properties of dendrites in biological neurons, our readout stage incorporates neurons having multiple dendrites with a lumped nonlinearity (two compartment model). The number of synaptic connections on each branch is significantly lower than the total number of connections from the liquid neurons and the learning algorithm tries to find the best 'combination' of input connections on each branch to reduce the error. Hence, the learning involves network rewiring (NRW) of the readout network similar to structural plasticity observed in its biological counterparts. We show that compared to a single perceptron using analog weights, this architecture for the readout can attain, even by using the same number of binary valued synapses, up to 3.3 times less error for a two-class spike train classification problem and 2.4 times less error for an input rate approximation task. Even with 60 times larger synapses, a group of 60 parallel perceptrons cannot attain the performance of the proposed dendritically enhanced readout. An additional advantage of this method for hardware implementations is that the 'choice' of connectivity can be easily implemented exploiting address event representation (AER) protocols commonly used in current neuromorphic systems where the connection matrix is stored in memory. Also, due to the use of binary synapses, our proposed method is more robust against statistical variations.

  9. Plasmacytoid dendritic cells are inefficient in activation of human regulatory T cells.

    Directory of Open Access Journals (Sweden)

    Mario Hubo

    Full Text Available BACKGROUND: Dendritic cells (DC play a key role in initiation and regulation of immune responses. Plasmacytoid DC (pDC, a small subset of DC, characterized as type-I interferon producing cells, are critically involved in anti-viral immune responses, but also mediate tolerance by induction of regulatory T cells (Treg. In this study, we compared the capacity of human pDC and conventional DC (cDC to modulate T cell activity in presence of Foxp3(+ Treg. PRINCIPAL FINDINGS: In coculture of T effector cells (Teff and Treg, activated cDC overcome Treg anergy, abrogate their suppressive function and induce Teff proliferation. In contrast, pDC do not break Treg anergy but induce Teff proliferation even in coculture with Treg. Lack of Treg-mediated suppression is independent of proinflammatory cytokines like IFN-α, IL-1, IL-6 and TNF-α. Phenotyping of pDC-stimulated Treg reveals a reduced expression of Treg activation markers GARP and CTLA-4. Additional stimulation by anti-CD3 antibodies enhances surface expression of GARP and CTLA-4 on Treg and consequently reconstitutes their suppressive function, while increased costimulation with anti-CD28 antibodies is ineffective. CONCLUSIONS/SIGNIFICANCE: Our data show that activated pDC induce Teff proliferation, but are insufficient for functional Treg activation and, therefore, allow expansion of Teff also in presence of Treg.

  10. Impaired dendritic inhibition leads to epileptic activity in a computer model of CA3.

    Science.gov (United States)

    Sanjay, M; Neymotin, Samuel A; Krothapalli, Srinivasa B

    2015-11-01

    Temporal lobe epilepsy (TLE) is a common type of epilepsy with hippocampus as the usual site of origin. The CA3 subfield of hippocampus is reported to have a low epileptic threshold and hence initiates the disorder in patients with TLE. This study computationally investigates how impaired dendritic inhibition of pyramidal cells in the vulnerable CA3 subfield leads to generation of epileptic activity. A model of CA3 subfield consisting of 800 pyramidal cells, 200 basket cells (BC) and 200 Oriens-Lacunosum Moleculare (O-LM) interneurons was used. The dendritic inhibition provided by O-LM interneurons is reported to be selectively impaired in some TLEs. A step-wise approach is taken to investigate how alterations in network connectivity lead to generation of epileptic patterns. Initially, dendritic inhibition alone was reduced, followed by an increase in the external inputs received at the distal dendrites of pyramidal cells, and finally additional changes were made at the synapses between all neurons in the network. In the first case, when the dendritic inhibition of pyramidal cells alone was reduced, the local field potential activity changed from a theta-modulated gamma pattern to a prominently gamma frequency pattern. In the second case, in addition to this reduction of dendritic inhibition, with a simultaneous large increase in the external excitatory inputs received by pyramidal cells, the basket cells entered a state of depolarization block, causing the network to generate a typical ictal activity pattern. In the third case, when the dendritic inhibition onto the pyramidal cells was reduced and changes were simultaneously made in synaptic connectivity between all neurons in the network, the basket cells were again observed to enter depolarization block. In the third case, impairment of dendritic inhibition required to generate an ictal activity pattern was lesser than the two previous cases. Moreover, the ictal like activity began earlier in the third case

  11. Activation of toll-like receptors and dendritic cells by a broad range of bacterial molecules

    NARCIS (Netherlands)

    Boele, L.C.L.; Bajramovic, J.J.; Vries, A.M.M.B.C. de; Voskamp-Visser, I.A.I.; Kaman, W.E.; Kleij, D. van der

    2009-01-01

    Activation of pattern recognition receptors such as Toll-like receptors (TLRs) by pathogens leads to activation and maturation of dendritic cells (DC), which orchestrate the development of the adaptive immune response. To create an overview of the effects of a broad range of pathogenic bacteria, the

  12. In vivo blockade of neural activity alters dendritic development of neonatal CA1 pyramidal cells.

    Science.gov (United States)

    Groc, Laurent; Petanjek, Zdravko; Gustafsson, Bengt; Ben-Ari, Yehezkel; Hanse, Eric; Khazipov, Roustem

    2002-11-01

    During development, neural activity has been proposed to promote neuronal growth. During the first postnatal week, the hippocampus is characterized by an oscillating neural network activity and a rapid neuronal growth. In the present study we tested in vivo, by injecting tetanus toxin into the hippocampus of P1 rats, whether this neural activity indeed promotes growth of pyramidal cells. We have previously shown that tetanus toxin injection leads to a strong reduction in the frequency of spontaneous GABA and glutamatergic synaptic currents, and to a complete blockade of the early neural network activity during the first postnatal week. Morphology of neurobiotin-filled CA1 pyramidal cells was analyzed at the end of the first postnatal week (P6-10). In activity-reduced neurons, the total length of basal dendritic tree was three times less than control. The number, but not the length, of basal dendritic branches was affected. The growth impairment was restricted to the basal dendrites. The apical dendrite, the axons, or the soma grew normally during activity deprivation. Thus, the in vivo neural activity in the neonate hippocampus seems to promote neuronal growth by initiating novel branches.

  13. Strings on a Violin: Location Dependence of Frequency Tuning in Active Dendrites

    Science.gov (United States)

    Das, Anindita; Rathour, Rahul K.; Narayanan, Rishikesh

    2017-01-01

    Strings on a violin are tuned to generate distinct sound frequencies in a manner that is firmly dependent on finger location along the fingerboard. Sound frequencies emerging from different violins could be very different based on their architecture, the nature of strings and their tuning. Analogously, active neuronal dendrites, dendrites endowed with active channel conductances, are tuned to distinct input frequencies in a manner that is dependent on the dendritic location of the synaptic inputs. Further, disparate channel expression profiles and differences in morphological characteristics could result in dendrites on different neurons of the same subtype tuned to distinct frequency ranges. Alternately, similar location-dependence along dendritic structures could be achieved through disparate combinations of channel profiles and morphological characteristics, leading to degeneracy in active dendritic spectral tuning. Akin to strings on a violin being tuned to different frequencies than those on a viola or a cello, different neuronal subtypes exhibit distinct channel profiles and disparate morphological characteristics endowing each neuronal subtype with unique location-dependent frequency selectivity. Finally, similar to the tunability of musical instruments to elicit distinct location-dependent sounds, neuronal frequency selectivity and its location-dependence are tunable through activity-dependent plasticity of ion channels and morphology. In this morceau, we explore the origins of neuronal frequency selectivity, and survey the literature on the mechanisms behind the emergence of location-dependence in distinct forms of frequency tuning. As a coda to this composition, we present some future directions for this exciting convergence of biophysical mechanisms that endow a neuron with frequency multiplexing capabilities.

  14. Dendrimer-like alpha-d-glucan nanoparticles activate dendritic cells and are effective vaccine adjuvants.

    Science.gov (United States)

    Lu, Fangjia; Mencia, Alejandra; Bi, Lin; Taylor, Aaron; Yao, Yuan; HogenEsch, Harm

    2015-04-28

    The use of nanoparticles for delivery of vaccine antigens and as vaccine adjuvants is appealing because their size allows efficient uptake by dendritic cells and their biological properties can be tailored to the desired function. Here, we report the effect of chemically modified phytoglycogen, a dendrimer-like α-d-glucan nanoparticle, on dendritic cells in vitro, and the utility of this type of nanoparticle as a vaccine adjuvant in vivo. The modified phytoglycogen nanoparticle, termed Nano-11, has a positive surface charge which enabled electrostatic adsorption of negatively charged protein antigens. The Nano-11-antigen complexes were efficiently phagocytized by dendritic cells. Nano-11 induced increased expression of costimulatory molecules and the secretion of IL-1β and IL-12p40 by dendritic cells. Intramuscular injection of Nano-11-antigen formulations induced a significantly enhanced immune response to two different protein antigens. Examination of the injection site revealed numerous monocytes and relatively few neutrophils at one day after injection. The inflammation had nearly completely disappeared by 2 weeks after injection. These studies indicate that Nano-11 is an effective vaccine delivery vehicle that significantly enhances the immune response. This type of plant based nanoparticle is considered highly cost-effective compared with fully synthetic nanoparticles and appears to have an excellent safety profile making them an attractive adjuvant candidate for prophylactic vaccines.

  15. Facile synthesis of dendritic gold nanostructures with hyperbranched architectures and their electrocatalytic activity toward ethanol oxidation.

    Science.gov (United States)

    Huang, Jianshe; Han, Xinyi; Wang, Dawei; Liu, Dong; You, Tianyan

    2013-09-25

    Gold dendritic nanostructures with hyperbranched architectures were synthesized by the galvanic replacement reaction between nickel wire and HAuCl4 in aqueous solution. The study revealed that the morphology of the obtained nanostructures strongly depended on experimental parameters such as the HAuCl4 solution concentration, reaction temperature, and time, as well as stirring or not. According to the investigation of the growth process, it was proposed that gold nanoparticles with rough surfaces were first deposited on the nickel substrate and that subsequent growth preferentially occurred on the preformed gold nanoparticles, finally leading to the formation of hyperbranched gold dendrites via a self-organization process under nonequilibrium conditions. The electrochemical experiment results demonstrated that the as-obtained gold dendrites exhibited high catalytic activity toward ethanol electrooxidation in alkaline solution, indicating that this nanomaterial may be a potential catalyst for direct ethanol fuel cells.

  16. Poly IC triggers a cathepsin D- and IPS-1-dependent pathway to enhance cytokine production and mediate dendritic cell necroptosis.

    Science.gov (United States)

    Zou, Jian; Kawai, Taro; Tsuchida, Tetsuo; Kozaki, Tatsuya; Tanaka, Hiroki; Shin, Kyung-Sue; Kumar, Himanshu; Akira, Shizuo

    2013-04-18

    RIG-I-like receptors (RLRs) sense virus-derived RNA or polyinosinic-polycytidylic acid (poly IC) to exert antiviral immune responses. Here, we examine the mechanisms underlying the adjuvant effects of poly IC. Poly IC was taken up by dendritic cells (DCs), and it induced lysosomal destabilization, which, in turn, activated an RLR-dependent signaling pathway. Upon poly IC stimulation, cathepsin D was released into the cytoplasm from the lysosome to interact with IPS-1, an adaptor molecule for RLRs. This interaction facilitated cathepsin D cleavage of caspase 8 and the activation of the transcription factor NF-κB, resulting in enhanced cytokine production. Further recruitment of the kinase RIP-1 to this complex initiated the necroptosis of a small number of DCs. HMGB1 released by dying cells enhanced IFN-β production in concert with poly IC. Collectively, these findings suggest that cathepsin D-triggered, IPS-1-dependent necroptosis is a mechanism that propagates the adjuvant efficacy of poly IC.

  17. Clitocybe nuda Activates Dendritic Cells and Acts as a DNA Vaccine Adjuvant

    Directory of Open Access Journals (Sweden)

    Mei-Hsing Chen

    2013-01-01

    Full Text Available This work represents the first evaluation of the effects of water extract of C. nuda (WE-CN, an edible mushroom, on murine bone marrow-derived dendritic cells (BMDCs and the potential pathway through which the effects are mediated. Our experimental results show that WE-CN could induce phenotypic maturation of DCs, as shown by the increased expression of MHC and costimulatory molecules. In addition, it also induced the proinflammatory cytokines expression on DCs and enhanced both the proliferation and IFN-γ secretion of allogenic T cells. Therefore, since WE-CN did not induce maturation of DCs generated from mice with mutated TLR-4 or TLR-2, suggesting that TLR4 and TLR2 might function as membrane receptors for WE-CN. Moreover, the mechanism of action of WE-CN may be mediated by increased phosphorylation of ERK, p38, and JNK mitogen-activated protein kinase (MAPK and increased NF-κB p65 activity, which are important signaling molecules downstream of TLR-4 and TLR-2. Finally, coimmunization of mice with WE-CN and a HER-2/neu DNA vaccine induced a HER-2/neu-specific Th1 response that resulted in significant inhibition of HER-2/neu overexpressing mouse bladder tumor (MBT-2 growth. These data suggest that WE-CN induces DC maturation through TLR-4 and/or TLR-2 and that WE-CN can be used as an adjuvant in cancer vaccine immunotherapy.

  18. Modification to the Capsid of the Adenovirus Vector That Enhances Dendritic Cell Infection and Transgene-Specific Cellular Immune Responses

    OpenAIRE

    Worgall, Stefan; Busch, Annette; Rivara, Michael; Bonnyay, David; Leopold, Philip L.; Merritt, Robert; Hackett, Neil R.; Rovelink, Peter W.; Joseph T Bruder; Wickham, Thomas J.; Kovesdi, Imi; Crystal, Ronald G.

    2004-01-01

    Adenovirus (Ad) gene transfer vectors can be used to transfer and express antigens and function as strong adjuvants and thus are useful platforms for the development of genetic vaccines. Based on the hypothesis that Ad vectors with enhanced infectibility of dendritic cells (DC) may be able to evoke enhanced immune responses against antigens encoded by the vector in vivo, the present study analyzes the vaccine potential of an Ad vector expressing β-galactosidase as a model antigen and genetica...

  19. Human intestinal dendritic cells decrease cytokine release against Salmonella infection in the presence of Lactobacillus paracasei upon TLR activation.

    Directory of Open Access Journals (Sweden)

    Miriam Bermudez-Brito

    Full Text Available Probiotic bacteria have been shown to modulate immune responses and could have therapeutic effects in allergic and inflammatory disorders. However, little is known about the signalling pathways that are engaged by probiotics. Dendritic cells (DCs are antigen-presenting cells that are involved in immunity and tolerance. Monocyte-derived dendritic cells (MoDCs and murine DCs are different from human gut DCs; therefore, in this study, we used human DCs generated from CD34+ progenitor cells (hematopoietic stem cells harvested from umbilical cord blood; those DCs exhibited surface antigens of dendritic Langerhans cells, similar to the lamina propria DCs in the gut. We report that both a novel probiotic strain isolated from faeces of exclusively breast-fed newborn infants, Lactobacillus paracasei CNCM I-4034, and its cell-free culture supernatant (CFS decreased pro-inflammatory cytokines and chemokines in human intestinal DCs challenged with Salmonella. Interestingly, the supernatant was as effective as the bacteria in reducing pro-inflammatory cytokine expression. In contrast, the bacterium was a potent inducer of TGF-β2 secretion, whereas the supernatant increased the secretion of TGF-β1 in response to Salmonella. We also showed that both the bacteria and its supernatant enhanced innate immunity through the activation of Toll-like receptor (TLR signalling. These treatments strongly induced the transcription of the TLR9 gene. In addition, upregulation of the CASP8 and TOLLIP genes was observed. This work demonstrates that L. paracasei CNCM I-4034 enhanced innate immune responses, as evidenced by the activation of TLR signalling and the downregulation of a broad array of pro-inflammatory cytokines. The use of supernatants like the one described in this paper could be an effective and safe alternative to using live bacteria in functional foods.

  20. Caspase-8 acts as a molecular rheostat to limit RIPK1- and MyD88-mediated dendritic cell activation.

    Science.gov (United States)

    Cuda, Carla M; Misharin, Alexander V; Gierut, Angelica K; Saber, Rana; Haines, G Kenneth; Hutcheson, Jack; Hedrick, Stephen M; Mohan, Chandra; Budinger, G Scott; Stehlik, Christian; Perlman, Harris

    2014-06-15

    Caspase-8, an executioner enzyme in the death receptor pathway, was shown to initiate apoptosis and suppress necroptosis. In this study, we identify a novel, cell death-independent role for caspase-8 in dendritic cells (DCs): DC-specific expression of caspase-8 prevents the onset of systemic autoimmunity. Failure to express caspase-8 has no effect on the lifespan of DCs but instead leads to an enhanced intrinsic activation and, subsequently, more mature and autoreactive lymphocytes. Uncontrolled TLR activation in a RIPK1-dependent manner is responsible for the enhanced functionality of caspase-8-deficient DCs, because deletion of the TLR-signaling mediator, MyD88, ameliorates systemic autoimmunity induced by caspase-8 deficiency. Taken together, these data demonstrate that caspase-8 functions in a cell type-specific manner and acts uniquely in DCs to maintain tolerance.

  1. Enhancement of dendritic branching in cultured hippocampal neurons by 17beta-estradiol is mediated by nitric oxide.

    Science.gov (United States)

    Audesirk, T; Cabell, L; Kern, M; Audesirk, G

    2003-06-01

    Both 17beta-estradiol (E2) and nitric oxide (NO) are important in neuronal development, learning and memory, and age-related memory changes. There is growing evidence that a number of estrogen receptor-mediated effects of estradiol utilize nitric oxide as an intermediary. The role of estradiol in hippocampal neuronal differentiation and function has particular implications for learning and memory. Low levels of estradiol (10nM) significantly increase dendritic branching in cultured embryonic rat hippocampal neurons (158% of control). This study investigates the hypothesis that the estrogen-stimulated increase in dendritic branching is mediated by nitric oxide. We found that nitric oxide donors also produce significantly increased dendritic branching S-nitroso-N-acetylpenicillamine (SNAP: 119%; 2,2'-(hydroxynitrosohydrazino)bis-ethanamine (NOC-18): 128% of control). We then determined that the increases in dendritic branching stimulated by estradiol or by a nitric oxide donor were both blocked by an inhibitor of guanylyl cyclase. Dendritic branching was also stimulated by a cell permeable analog of cyclic guanosine monophosphate (dibutyryl-cGMP: 173% of control). Estradiol-stimulated dendritic branching was reversed by the nitric oxide scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethyl imidazoline-1-oxyl 3-oxide (carboxy-PTIO). This study provides evidence that estradiol influences the development of embryonic hippocampal neurons in culture by increasing the production of nitric oxide or by increasing the sensitivity of the neurons to nitric oxide. Nitric oxide in turn stimulates dendritic branching via activation of guanylyl cyclase.

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

    Science.gov (United States)

    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.

  3. Downregulation of transient K+ channels in dendrites of hippocampal CA1 pyramidal neurons by activation of PKA and PKC.

    Science.gov (United States)

    Hoffman, D A; Johnston, D

    1998-05-15

    We have reported recently a high density of transient A-type K+ channels located in the distal dendrites of CA1 hippocampal pyramidal neurons and shown that these channels shape EPSPs, limit the back-propagation of action potentials, and prevent dendritic action potential initiation (). Because of the importance of these channels in dendritic signal propagation, their modulation by protein kinases would be of significant interest. We investigated the effects of activators of cAMP-dependent protein kinase (PKA) and the Ca2+-dependent phospholipid-sensitive protein kinase (PKC) on K+ channels in cell-attached patches from the distal dendrites of hippocampal CA1 pyramidal neurons. Inclusion of the membrane-permeant PKA activators 8-bromo-cAMP (8-br-cAMP) or forskolin in the dendritic patch pipette resulted in a depolarizing shift in the activation curve for the transient channels of approximately 15 mV. Activation of PKC by either of two phorbol esters also resulted in a 15 mV depolarizing shift of the activation curve. Neither PKA nor PKC activation affected the sustained or slowly inactivating component of the total outward current. This downregulation of transient K+ channels in the distal dendrites may be responsible for some of the frequently reported increases in cell excitability found after PKA and PKC activation. In support of this hypothesis, we found that activation of either PKA or PKC significantly increased the amplitude of back-propagating action potentials in distal dendrites.

  4. Collagen I-induced dendritic cells activation is regulated by TNF- production through down-regulation of IRF4

    Indian Academy of Sciences (India)

    Barun Poudel; Hyeon-Hui Ki; Young-Mi Lee; Dae-Ki Kim

    2015-03-01

    Previously we have shown that collagen I enhances the maturation and function of dendritic cells (DCs). Inflammatory mediators such as tumour necrosis factor (TNF)-, interleukin (IL)-1 and lipopolysaccharide (LPS) are also known to activate DCs. Here we investigated the involvement of TNF- on the collagen I-induced DCs activation. TNF-a neutralization inhibited collagen I-induced IL-12 secretions by DCs. Additionally, we observed suppression of collagen I-induced costimulatory molecules expression along with down-regulation of genes involved in DCs activation pathway. Furthermore, TNF- inhibition upon collagen Istimulation up-regulated the expression of interferon regulatory transcription factor IRF4, when compared to collagen I only treated cells. Collectively, our data demonstrate that collagen I induce TNF- production, which is crucial for the activation and function of DCs, through down-regulation of IRF4, and implicates the importance in development of anti- TNF- therapeutics for several inflammatory diseases.

  5. Virulent Salmonella enterica serovar typhimurium evades adaptive immunity by preventing dendritic cells from activating T cells.

    Science.gov (United States)

    Tobar, Jaime A; Carreño, Leandro J; Bueno, Susan M; González, Pablo A; Mora, Jorge E; Quezada, Sergio A; Kalergis, Alexis M

    2006-11-01

    Dendritic cells (DCs) constitute the link between innate and adaptive immunity by directly recognizing pathogen-associated molecular patterns (PAMPs) in bacteria and by presenting bacterial antigens to T cells. Recognition of PAMPs renders DCs as professional antigen-presenting cells able to prime naïve T cells and initiate adaptive immunity against bacteria. Therefore, interfering with DC function would promote bacterial survival and dissemination. Understanding the molecular mechanisms that have evolved in virulent bacteria to evade activation of adaptive immunity requires the characterization of virulence factors that interfere with DC function. Salmonella enterica serovar Typhimurium, the causative agent of typhoid-like disease in the mouse, can prevent antigen presentation to T cells by avoiding lysosomal degradation in DCs. Here, we show that this feature of virulent Salmonella applies in vivo to prevent activation of adaptive immunity. In addition, this attribute of virulent Salmonella requires functional expression of a type three secretion system (TTSS) and effector proteins encoded within the Salmonella pathogenicity island 2 (SPI-2). In contrast to wild-type virulent Salmonella, mutant strains carrying specific deletions of SPI-2 genes encoding TTSS components or effectors proteins are targeted to lysosomes and are no longer able to prevent DCs from activating T cells in vitro or in vivo. SPI-2 mutant strains are attenuated in vivo, showing reduced tissue colonization and enhanced T-cell activation, which confers protection against a challenge with wild-type virulent Salmonella. Our data suggest that impairment of DC function by the activity of SPI-2 gene products is crucial for Salmonella pathogenesis.

  6. Early cytoskeletal rearrangement during dendritic cell maturation enhances synapse formation and Ca(2+) signaling in CD8(+) T cells.

    Science.gov (United States)

    Averbeck, Marco; Braun, Thorsten; Pfeifer, Gunther; Sleeman, Jonathan; Dudda, Jan; Martin, Stefan F; Kremer, Bernhard; Aktories, Klaus; Simon, Jan C; Termeer, Christian

    2004-10-01

    The interplay between dendritic cells (DC) and T cells is a dynamic process critically depending on DC maturation. Ca(2+) influx is one of the initial events occurring during DC/T cell contacts. To determine how DC maturation influences DC/T cell contacts, time-lapse video microscopy was established using TCR-transgenic CD8(+) T cells from P14 mice. DC maturation shifted DC/T cell contacts from short-lived interactions with transient Ca(2+) influx in T cells to long-lasting interactions and sustained Ca(2+) influx of 30 min and more. Follow-up of DC/T cell interactions after 2 h using confocal microscopy revealed that long-lasting Ca(2+) responses in T cells were preferentially associated with the formation of an immunological synapse involving CD54 and H2-K(b) at the DC/T cell interface. Such synapse formation preceded MHC or B7 up-regulation, since DC developed into potent Ca(2+) stimulators 7 h after initiation of maturation. Instead, the enhanced capacity of 7 h-matured DC to induce sustained Ca(2+) responses in CD8(+) T cells is critically dependent on the polarization and rearrangement of the cytoskeleton, as shown by Clostridium difficile toxin B inhibitor experiments. These data indicate that already very early after receiving a maturation stimulus, DC display enhanced cytoskeletal activity resulting in the rapid formation of immunological synapses and effective CD8(+) T cell stimulation.

  7. Infected dendritic cells are sufficient to mediate the adjuvant activity generated by Venezuelan equine encephalitis virus replicon particles.

    Science.gov (United States)

    Tonkin, Daniel R; Whitmore, Alan; Johnston, Robert E; Barro, Mario

    2012-06-22

    Replicon particles derived from Venezuelan equine encephalitis virus (VEE) are infectious non-propagating particles which act as a safe and potent systemic, mucosal, and cellular adjuvant when delivered with antigen. VEE and VEE replicon particles (VRP) can target multiple cell types including dendritic cells (DCs). The role of these cell types in VRP adjuvant activity has not been previously evaluated, and for these studies we focused on the contribution of DCs to the response to VRP. By analysis of VRP targeting in the draining lymph node, we found that VRP induced rapid recruitment of TNF-secreting monocyte-derived inflammatory dendritic cells. VRP preferentially infected these inflammatory DCs as well as classical DCs and macrophages, with less efficient infection of other cell types. DC depletion suggested that the interaction of VRP with classical DCs was required for recruitment of inflammatory DCs, induction of high levels of many cytokines, and for stable transport of VRP to the draining lymph node. Additionally, in vitro-infected DCs enhanced antigen-specific responses by CD4 and CD8 T cells. By transfer of VRP-infected DCs into mice we showed that these DCs generated an inflammatory state in the draining lymph node similar to that achieved by VRP injection. Most importantly, VRP-infected DCs were sufficient to establish robust adjuvant activity in mice comparable to that produced by VRP injection. These findings indicate that VRP infect, recruit and activate both classical and inflammatory DCs, and those DCs become mediators of the VRP adjuvant activity.

  8. Sirtuin 1 Regulates Dendritic Cell Activation and Autophagy during Respiratory Syncytial Virus-Induced Immune Responses.

    Science.gov (United States)

    Owczarczyk, Anna B; Schaller, Matthew A; Reed, Michelle; Rasky, Andrew J; Lombard, David B; Lukacs, Nicholas W

    2015-08-15

    Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infection in children worldwide. Sirtuin 1 (SIRT1), an NAD(+)-dependent deacetylase, has been associated with the induction of autophagy and the regulation of inflammatory mediators. We found that Sirt1 was upregulated in mouse lung after RSV infection. Infected animals that received EX-527, a selective SIRT1 inhibitor, displayed exacerbated lung pathology, with increased mucus production, elevated viral load, and enhanced Th2 cytokine production. Gene expression analysis of isolated cell populations revealed that Sirt1 was most highly upregulated in RSV-treated dendritic cells (DCs). Upon RSV infection, EX-527-treated DCs, Sirt1 small interfering RNA-treated DCs, or DCs from conditional knockout (Sirt1(f/f)-CD11c-Cre(+)) mice showed downregulated inflammatory cytokine gene expression and attenuated autophagy. Finally, RSV infection of Sirt1(f/f)-CD11c-Cre(+) mice resulted in altered lung and lymph node cytokine responses, leading to exacerbated pathology. These data indicate that SIRT1 promotes DC activation associated with autophagy-mediated processes during RSV infection, thereby directing efficient antiviral immune responses.

  9. Cdc42-dependent actin dynamics controls maturation and secretory activity of dendritic cells

    Science.gov (United States)

    Schulz, Anna M.; Stutte, Susanne; Hogl, Sebastian; Luckashenak, Nancy; Dudziak, Diana; Leroy, Céline; Forné, Ignasi; Imhof, Axel; Müller, Stephan A.; Brakebusch, Cord H.; Lichtenthaler, Stefan F.

    2015-01-01

    Cell division cycle 42 (Cdc42) is a member of the Rho guanosine triphosphatase family and has pivotal functions in actin organization, cell migration, and proliferation. To further study the molecular mechanisms of dendritic cell (DC) regulation by Cdc42, we used Cdc42-deficient DCs. Cdc42 deficiency renders DCs phenotypically mature as they up-regulate the co-stimulatory molecule CD86 from intracellular storages to the cell surface. Cdc42 knockout DCs also accumulate high amounts of invariant chain–major histocompatibility complex (MHC) class II complexes at the cell surface, which cannot efficiently present peptide antigens (Ag’s) for priming of Ag-specific CD4 T cells. Proteome analyses showed a significant reduction in lysosomal MHC class II–processing proteins, such as cathepsins, which are lost from DCs by enhanced secretion. As these effects on DCs can be mimicked by chemical actin disruption, our results propose that Cdc42 control of actin dynamics keeps DCs in an immature state, and cessation of Cdc42 activity during DC maturation facilitates secretion as well as rapid up-regulation of intracellular molecules to the cell surface. PMID:26553928

  10. Perforin enhances the granulysin-induced lysis of Listeria innocua in human dendritic cells

    Directory of Open Access Journals (Sweden)

    Wagner Carsten A

    2007-08-01

    Full Text Available Abstract Background Cytotoxic T lymphocytes (CTL and natural killer (NK cells play an essential role in the host defence against intracellular pathogens such as Listeria, and Mycobacteria. The key mediator of bacteria-directed cytotoxicity is granulysin, a 9 kDa protein stored in cytolytic granules together with perforin and granzymes. Granulysin binds to cell membranes and is subsequently taken up via a lipid raft-associated mechanism. In dendritic cells (DC granulysin is further transferred via early endosomes to L. innocua-containing phagosomes were bacteriolysis is induced. In the present study we analysed the role of perforin in granulysin-induced intracellular bacteriolysis in DC. Results We found granulysin-induced lysis of intracellular Listeria significantly increased when perforin was simultaneously present. In pulse-chase experiments enhanced bacteriolysis was observed when perforin was added up to 25 minutes after loading the cells with granulysin demonstrating no ultimate need for simultaneous uptake of granulysin and perforin. The perforin concentration sufficient to enhance granulysin-induced intracellular bacteriolysis did not cause permanent membrane pores in Listeria-challenged DC as shown by dye exclusion test and LDH release. This was in contrast to non challenged DC that were more susceptible to perforin lysis. For Listeria-challenged DC, there was clear evidence for an Ca2+ influx in response to sublytic perforin demonstrating a short-lived change in the plasma membrane permeability. Perforin treatment did not affect granulysin binding, initial uptake or intracellular trafficking to early endosomes. However, enhanced colocalization of granulysin with listerial DNA in presence of perforin was found by confocal laser scanning microscopy. Conclusion The results provide evidence that perforin increases granulysin-mediated killing of intracellular Listeria by enhanced phagosome-endosome fusion triggered by a transient Ca2+ flux.

  11. The BDNF effects on dendritic spines of mature hippocampal neurons depend on neuronal activity

    Directory of Open Access Journals (Sweden)

    Yves eKellner

    2014-03-01

    Full Text Available The fine tuning of neural networks during development and learning relies upon both functional and structural plastic processes. Changes in the number as well as in the size and shape of dendritic spines are associated to long-term activity-dependent synaptic plasticity. However, the molecular mechanisms translating functional into structural changes are still largely unknown. In this context, neurotrophins, like Brain-Derived Neurotrophic Factor (BDNF, are among promising candidates. Specifically BDNF-TrkB receptor signaling is crucial for activity-dependent strengthening of synapses in different brain regions. BDNF application has been shown to positively modulate dendritic and spine architecture in cortical and hippocampal neurons as well as structural plasticity in vitro. However, a global BDNF deprivation throughout the central nervous system (CNS resulted in very mild structural alterations of dendritic spines, questioning the relevance of the endogenous BDNF signaling in modulating the development and the mature structure of neurons in vivo. Here we show that a loss-of-function approach, blocking BDNF results in a significant reduction in dendritic spine density, associated with an increase in spine length and a decrease in head width. These changes are associated with a decrease in F-actin levels within spine heads. On the other hand, a gain-of-function approach, applying exogenous BDNF, could not reproduce the increase in spine density or the changes in spine morphology previously described. Taken together, we show here that the effects exerted by BDNF on the dendritic architecture of hippocampal neurons are dependent on the neuron’s maturation stage. Indeed, in mature hippocampal neurons in vitro as shown in vivo BDNF is specifically required for the activity-dependent maintenance of the mature spine phenotype.

  12. Breast regression protein-39 (BRP-39) promotes dendritic cell maturation in vitro and enhances Th2 inflammation in murine model of asthma

    Institute of Scientific and Technical Information of China (English)

    Qian xu; Shou-jie CHAI; Ying-ying QIAN; Min ZHANG; Kai WANG

    2012-01-01

    Aim: To determine the roles of breast regression protein-39 (BRP-39) in regulating dendritic cell maturation and in pathology of acute asthma.Methods: Mouse bone marrow-derived dendritic cells (BMDCs) were prepared,and infected with adenovirus over-expressing BRP-39.Ovalbumin (OVA)-induced murine model of acute asthma was made in female BALB/c mice by sensitizing and challenging with chicken OVA and Imject Alum.The transfected BMDCs were adoptively transferred into OVA-treated mice via intravenous injection.Airway hyperresponsiveness (AHR),inflammation and pulmonary histopathology were characterized.Results: The expression of BRP-39 mRNA and protein was significantly increased in lung tissues of OVA-treated mice.The BMDCs infected with adenovirus BRP-39 exhibited greater maturation and higher activity in vitro.Adoptive transfer of the cells into OVA-treated mice significantly augmented OVA-induced AHR and eosinophilic inflammation.Meanwhile,BRP-39 further enhanced the production of OVA-induced Th2 cytokines IL-4,IL-5,and IL-13,but significantly attenuated OVA-induced IFN-γ production in bronchoalveolar lavage fluid.Conclusion: In OVA-induced murine model of acute asthma,BRP-39 is over-expressed in lung tissue and augments Th2 inflammatory response and AHR.BRP-39 promotes dendritic cell maturation in vitro.Therefore,BRP-39 may be a potential therapeutic target of asthma.

  13. Amorphous silica nanoparticles enhance cross-presentation in murine dendritic cells

    Energy Technology Data Exchange (ETDEWEB)

    Hirai, Toshiro [Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Yoshioka, Yasuo, E-mail: yasuo@phs.osaka-u.ac.jp [Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Takahashi, Hideki; Ichihashi, Ko-ichi; Yoshida, Tokuyuki; Tochigi, Saeko [Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Nagano, Kazuya [Laboratory of Biopharmaceutical Research, National Institute of Biomedical Innovation, 7-6-8 Saitoasagi, Ibaraki, Osaka 567-0085 (Japan); Abe, Yasuhiro [Cancer Biology Research Center, Sanford Research/USD, 2301 E. 60th Street N, Sioux Falls, SD 57104 (United States); Kamada, Haruhiko; Tsunoda, Shin-ichi [Laboratory of Biopharmaceutical Research, National Institute of Biomedical Innovation, 7-6-8 Saitoasagi, Ibaraki, Osaka 567-0085 (Japan); The Center for Advanced Medical Engineering and Informatics, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Nabeshi, Hiromi [Division of Foods, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501 (Japan); Yoshikawa, Tomoaki [Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Tsutsumi, Yasuo, E-mail: ytsutsumi@phs.osaka-u.ac.jp [Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Laboratory of Biopharmaceutical Research, National Institute of Biomedical Innovation, 7-6-8 Saitoasagi, Ibaraki, Osaka 567-0085 (Japan); The Center for Advanced Medical Engineering and Informatics, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer Silica nanoparticles enhanced cross-presentation. Black-Right-Pointing-Pointer Silica nanoparticles induced endosomal release of exogenous antigens. Black-Right-Pointing-Pointer Silica nanoparticle-induced cross-presentation was mediated by scavenger receptors. Black-Right-Pointing-Pointer Surface-modification may enable the manufacture of safer silica nanoparticles. -- Abstract: Nanomaterials (NMs) exhibit unique physicochemical properties and innovative functions, and they are increasingly being used in a wide variety of fields. Ensuring the safety of NMs is now an urgent task. Recently, we reported that amorphous silica nanoparticles (nSPs), one of the most widely used NMs, enhance antigen-specific cellular immune responses and may therefore aggravate immune diseases. Thus, to ensure the design of safer nSPs, investigations into the effect of nSPs on antigen presentation in dendritic cells, which are central orchestrators of the adaptive immune response, are now needed. Here, we show that nSPs with diameters of 70 and 100 nm enhanced exogenous antigen entry into the cytosol from endosomes and induced cross-presentation, whereas submicron-sized silica particles (>100 nm) did not. Furthermore, we show that surface modification of nSPs suppressed cross-presentation. Although further studies are required to investigate whether surface-modified nSPs suppress immune-modulating effects in vivo, the current results indicate that appropriate regulation of the characteristics of nSPs, such as size and surface properties, will be critical for the design of safer nSPs.

  14. Rhythmic dendritic Ca2+ oscillations in thalamocortical neurons during slow non-REM sleep-related activity in vitro.

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    Errington, Adam C; Hughes, Stuart W; Crunelli, Vincenzo

    2012-08-15

    The distribution of T-type Ca2+ channels along the entire somatodendritic axis of sensory thalamocortical (TC) neurons permits regenerative propagation of low threshold spikes (LTS) accompanied by global dendritic Ca2+ influx. Furthermore, T-type Ca2+ channels play an integral role in low frequency oscillatory activity (dynamics of T-type Ca2+ channel-dependent dendritic Ca2+ signalling during slow sleep-associated oscillations remains unknown. Here we demonstrate using patch clamp recording and two-photon Ca2+ imaging of dendrites from cat TC neurons undergoing spontaneous slow oscillatory activity that somatically recorded δ (1–4 Hz) and slow (<1 Hz) oscillations are associated with rhythmic and sustained global oscillations in dendritic Ca2+. In addition, our data reveal the presence of LTS-dependent Ca2+ transients (Δ[Ca2+]) in dendritic spine-like structures on proximal TC neuron dendrites during slow (<1 Hz) oscillations whose amplitudes are similar to those observed in the dendritic shaft. We find that the amplitude of oscillation associated Δ[Ca2+] do not vary significantly with distance from the soma whereas the decay time constant (τdecay) of Δ[Ca2+] decreases significantly in more distal dendrites. Furthermore, τdecay of dendritic Δ[Ca2+] increases significantly as oscillation frequency decreases from δ to slow frequencies where pronounced depolarised UP states are observed. Such rhythmic dendritic Ca2+ entry in TC neurons during sleep-related firing patterns could be an important factor in maintaining the oscillatory activity and associated biochemical signalling processes, such as synaptic downscaling, that occur in non-REM sleep.

  15. Rationale for a multimodality strategy to enhance the efficacy of dendritic cell-based cancer immunotherapy

    Directory of Open Access Journals (Sweden)

    Jashodeep eDatta

    2015-06-01

    Full Text Available Dendritic cells (DC, master antigen-presenting cells that orchestrate interactions between the adaptive and innate immune arms, are increasingly utilized in cancer immunotherapy. Despite remarkable progress in our understanding of DC immunobiology, as well as several encouraging clinical applications — such as DC-based sipuleucel-T for metastatic castration-resistant prostate cancer — clinically effective DC-based immunotherapy as monotherapy for a majority of tumors remains a distant goal. The complex interplay between diverse molecular and immune processes that govern resistance to DC-based vaccination compels a multimodality approach, encompassing a growing arsenal of antitumor agents which target these distinct processes and synergistically enhance DC function. These include antibody-based targeted molecular therapies, immune checkpoint inhibitors, therapies that inhibit immunosuppressive cellular elements, conventional cytotoxic modalities, and immune potentiating adjuvants. It is likely that in the emerging era of precision cancer therapeutics, tangible clinical benefits will only be realized with a multifaceted—and personalized—approach combining DC-based vaccination with adjunctive strategies.

  16. In vitro enhancement of dendritic cell-mediated anti-glioma immune response by graphene oxide

    Science.gov (United States)

    Wang, Wei; Li, Zhongjun; Duan, Jinhong; Wang, Chen; Fang, Ying; Yang, Xian-Da

    2014-06-01

    Malignant glioma has extremely poor prognosis despite combination treatments with surgery, radiation, and chemotherapy. Dendritic cell (DC)-based immunotherapy may potentially serve as an adjuvant treatment of glioma, but its efficacy generally needs further improvement. Here we explored whether graphene oxide (GO) nanosheets could modulate the DC-mediated anti-glioma immune response in vitro, using the T98G human glioma cell line as the study model. Pulsing DCs with a glioma peptide antigen (Ag) generated a limited anti-glioma response compared to un-pulsed DCs. Pulsing DCs with GO alone failed to produce obvious immune modulation effects. However, stimulating DCs with a mixture of GO and Ag (GO-Ag) significantly enhanced the anti-glioma immune reaction ( p < 0.05). The secretion of interferon gamma (IFN-γ) by the lymphocytes was also markedly boosted by GO-Ag. Additionally, the anti-glioma immune response induced by GO-Ag appeared to be target-specific. Furthermore, at the concentration used in this study, GO exhibited a negligible effect on the viability of the DCs. These results suggested that GO might have potential utility for boosting a DC-mediated anti-glioma immune response.

  17. Enhanced immunogenicity of a tricomponent mannan tetanus toxoid conjugate vaccine targeted to dendritic cells via Dectin-1 by incorporating β-glucan.

    Science.gov (United States)

    Lipinski, Tomasz; Fitieh, Amira; St Pierre, Joëlle; Ostergaard, Hanne L; Bundle, David R; Touret, Nicolas

    2013-04-15

    In a previous attempt to generate a protective vaccine against Candida albicans, a β-mannan tetanus toxoid conjugate showed poor immunogenicity in mice. To improve the specific activation toward the fungal pathogen, we aimed to target Dectin-1, a pattern-recognition receptor expressed on monocytes, macrophages, and dendritic cells. Laminarin, a β-glucan ligand of Dectin-1, was incorporated into the original β-mannan tetanus toxoid conjugate providing a tricomponent conjugate vaccine. A macrophage cell line expressing Dectin-1 was employed to show binding and activation of Dectin-1 signal transduction pathway by the β-glucan-containing vaccine. Ligand binding to Dectin-1 resulted in the following: 1) activation of Src family kinases and Syk revealed by their recruitment and phosphorylation in the vicinity of bound conjugate and 2) translocation of NF-κB to the nucleus. Treatment of immature bone marrow-derived dendritic cells (BMDCs) with tricomponent or control vaccine confirmed that the β-glucan-containing vaccine exerted its enhanced activity by virtue of dendritic cell targeting and uptake. Immature primary cells stimulated by the tricomponent vaccine, but not the β-mannan tetanus toxoid vaccine, showed activation of BMDCs. Moreover, treated BMDCs secreted increased levels of several cytokines, including TGF-β and IL-6, which are known activators of Th17 cells. Immunization of mice with the novel type of vaccine resulted in improved immune response manifested by high titers of Ab recognizing C. albicans β-mannan Ag. Vaccine containing laminarin also affected distribution of IgG subclasses, showing that vaccine targeting to Dectin-1 receptor can benefit from augmentation and immunomodulation of the immune response.

  18. Depletion of dendritic cells enhances innate anti-bacterial host defense through modulation of phagocyte homeostasis.

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    Stella E Autenrieth

    2012-02-01

    Full Text Available Dendritic cells (DCs as professional antigen-presenting cells play an important role in the initiation and modulation of the adaptive immune response. However, their role in the innate immune response against bacterial infections is not completely defined. Here we have analyzed the role of DCs and their impact on the innate anti-bacterial host defense in an experimental infection model of Yersinia enterocolitica (Ye. We used CD11c-diphtheria toxin (DT mice to deplete DCs prior to severe infection with Ye. DC depletion significantly increased animal survival after Ye infection. The bacterial load in the spleen of DC-depleted mice was significantly lower than that of control mice throughout the infection. DC depletion was accompanied by an increase in the serum levels of CXCL1, G-CSF, IL-1α, and CCL2 and an increase in the numbers of splenic phagocytes. Functionally, splenocytes from DC-depleted mice exhibited an increased bacterial killing capacity compared to splenocytes from control mice. Cellular studies further showed that this was due to an increased production of reactive oxygen species (ROS by neutrophils. Adoptive transfer of neutrophils from DC-depleted mice into control mice prior to Ye infection reduced the bacterial load to the level of Ye-infected DC-depleted mice, suggesting that the increased number of phagocytes with additional ROS production account for the decreased bacterial load. Furthermore, after incubation with serum from DC-depleted mice splenocytes from control mice increased their bacterial killing capacity, most likely due to enhanced ROS production by neutrophils, indicating that serum factors from DC-depleted mice account for this effect. In summary, we could show that DC depletion triggers phagocyte accumulation in the spleen and enhances their anti-bacterial killing capacity upon bacterial infection.

  19. Adjuvant properties of thermal component of hyperthermia enhanced transdermal immunization: effect on dendritic cells.

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    Neha Joshi

    Full Text Available Hyperthermia enhanced transdermal (HET immunization is a novel needle free immunization strategy employing application of antigen along with mild local hyperthermia (42°C to intact skin resulting in detectable antigen specific Ig in serum. In the present study, we investigated the adjuvant effect of thermal component of HET immunization in terms of maturation of dendritic cells and its implication on the quality of the immune outcome in terms of antibody production upon HET immunization with tetanus toxoid (TT. We have shown that in vitro hyperthermia exposure at 42°C for 30 minutes up regulates the surface expression of maturation markers on bone marrow derived DCs. This observation correlated in vivo with an increased and accelerated expression of maturation markers on DCs in the draining lymph node upon HET immunization in mice. This effect was found to be independent of the antigen delivered and depends only on the thermal component of HET immunization. In vitro hyperthermia also led to enhanced capacity to stimulate CD4+ T cells in allo MLR and promotes the secretion of IL-10 by BMDCs, suggesting a potential for Th2 skewing of T cell response. HET immunization also induced a systemic T cell response to TT, as suggested by proliferation of splenocytes from immunized animal upon in vitro stimulation by TT. Exposure to heat during primary immunization led to generation of mainly IgG class of antibodies upon boosting, similar to the use of conventional alum adjuvant, thus highlighting the adjuvant potential of heat during HET immunization. Lastly, we have shown that mice immunized by tetanus toxoid using HET route exhibited protection against challenge with a lethal dose of tetanus toxin. Thus, in addition to being a painless, needle free delivery system it also has an immune modulatory potential.

  20. Dendritic spikes amplify the synaptic signal to enhance detection of motion in a simulation of the direction-selective ganglion cell.

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    Michael J Schachter

    Full Text Available 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

  1. Comparative analysis of signature genes in PRRSV-infected porcine monocyte-derived dendritic cells at differential activation statuses

    Science.gov (United States)

    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...

  2. Burkholderia pseudomallei enhances maturation of bone marrow-derived dendritic cells.

    Science.gov (United States)

    Williams, Natasha L; Kloeze, Eveline; Govan, Brenda L; Körner, Heinrich; Ketheesan, Natkunam

    2008-12-01

    T-cell activation is essential for protection against Burkholderia pseudomallei infection. Using bone marrow-derived dendritic cells (BMDC) isolated from partially resistant C57BL/6 and susceptible BALB/c mice, the degree of BMDC activation in the presence of B. pseudomallei was investigated. Maturation, cytokine production and internalization of B. pseudomallei by BMDC was assessed in response to infection with a highly virulent and a low-virulent clinical isolate. Maturation was determined by identifying the up-regulation of cell-surface markers CD11c and CD86. IL-1beta and IL-12p40 expression were assessed by reverse-transcriptase PCR. The uptake of B. pseudomallei by BMDC was measured using an internalization assay. This study demonstrated that B. pseudomallei isolates stimulate the maturation of BMDC to the same degree regardless of virulence. However, maturation of BMDC was significantly increased in BALB/c mice compared with C57BL/6 mice. Additionally, the uptake of B. pseudomallei by BMDC was significantly greater with the highly virulent isolate compared with the low-virulent isolate. Expression of IL-12 and IL-1beta following infection with B. pseudomallei was up-regulated. The differences observed may have implications in the development of an effective immune response to B. pseudomallei.

  3. Enhanced antitumor immunity of nanoliposome-encapsulated heat shock protein 70 peptide complex derived from dendritic tumor fusion cells.

    Science.gov (United States)

    Zhang, Yunfei; Luo, Wen; Wang, Yucai; Chen, Jun; Liu, Yunyan; Zhang, Yong

    2015-06-01

    Tumor-derived heat shock proteins peptide complex (HSP.PC-Tu) has been regarded as a promising antitumor agent. However, inadequate immunogenicity and low bioavailability limit the clinical uses of this agent. In a previous study, we first produced an improved HSP70.PC-based vaccine purified from dendritic cell (DC)-tumor fusion cells (HSP70.PC-Fc) which had increased immunogenicity due to enhanced antigenic tumor peptides compared to HSP70.PC-Tu. In order to increase the bioavailability of HSP70.PC-Fc, the peptide complex was encapsulated with nanoliposomes (NL-HSP70.PC-Fc) in this study. After encapsulation, the tumor immunogenicity was observed using various assays. It was demonstrated that the NL-HSP70.PC-Fc has acceptable stability. The in vivo antitumor immune response was increased with regard to T-cell activation, CTL response and tumor therapy efficiency compared to that of HSP70.PC-Fc. In addition, it was shown that DC maturation was improved by NL-HSP70.PC-Fc, which added to the antitumor immunity. The results obtained for NL-HSP70.PC-Fc, which improved immunogenicity and increases the bioavailability of HSP70.PC, may represent superior heat shock proteins (HSPs)-based tumor vaccines. Such vaccines deserve further investigation and may provide a preclinical rationale to translate findings into early phase trials for patients with breast tumors.

  4. Enhancing whole-tumor cell vaccination by engaging innate immune system through NY-ESO-1/dendritic cell interactions.

    Science.gov (United States)

    Xu, Le; Zheng, Junying; Nguyen, David H; Luong, Quang T; Zeng, Gang

    2013-10-01

    NY-ESO-1 is a cancer/germline antigen (Ag) with distinctively strong immunogenicity. We have previously demonstrated that NY-ESO-1 serves as an endogenous adjuvant by engaging dendritic cell (DC)-surface receptors of calreticulin (CRT) and toll-like receptor (TLR) 4. In the present study, NY-ESO-1 was investigated for its immunomodulatory roles as a molecular adjuvant in whole-tumor cell vaccines using the Renca kidney cancer model. Renca cells were genetically engineered to express NY-ESO-1 on the cell surface to enhance direct interactions with DC. The effect of ectopic cell-surface expression of NY-ESO-1 was investigated on tumor immunogenicity, DC activation, cytotoxic T lymphocytes against model tumor-associated Ags, and the effectiveness of the modified tumor cells as a therapeutic whole-cell vaccine. Cell-surface expression of NY-ESO-1 was able to reduce the tumor growth of Renca cells in BALB/c mice, although the modification did not alter cell proliferation rate in vitro. Directly engaging the innate immune system through NY-ESO-1 facilitated the interaction of tumor cells with DC, leading to enhanced DC activation and subsequent tumor-specific T-cell priming. When used as a therapeutic whole-cell vaccine, Renca cells with NY-ESO-1 on the surface mediated stronger inhibitory effects on tumor growth and metastasis compared with parental Renca or Renca cells expressing a control protein GFP on the surface. Augmented antitumor efficacy correlated with increased CD8 T-cell infiltration into tumors and decreased myeloid-derived suppressor cells and regulatory T cells in the spleen. As a cancer/germline Ag and as an immunomodulatory adjuvant through engaging innate immune receptors, NY-ESO-1 offers a unique opportunity for improved whole-tumor cell vaccinations upon the classic GM-CSF-engineered cell vaccines.

  5. Electrical advantages of dendritic spines.

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    Allan T Gulledge

    Full Text Available Many neurons receive excitatory glutamatergic input almost exclusively onto dendritic spines. In the absence of spines, the amplitudes and kinetics of excitatory postsynaptic potentials (EPSPs at the site of synaptic input are highly variable and depend on dendritic location. We hypothesized that dendritic spines standardize the local geometry at the site of synaptic input, thereby reducing location-dependent variability of local EPSP properties. We tested this hypothesis using computational models of simplified and morphologically realistic spiny neurons that allow direct comparison of EPSPs generated on spine heads with EPSPs generated on dendritic shafts at the same dendritic locations. In all morphologies tested, spines greatly reduced location-dependent variability of local EPSP amplitude and kinetics, while having minimal impact on EPSPs measured at the soma. Spine-dependent standardization of local EPSP properties persisted across a range of physiologically relevant spine neck resistances, and in models with variable neck resistances. By reducing the variability of local EPSPs, spines standardized synaptic activation of NMDA receptors and voltage-gated calcium channels. Furthermore, spines enhanced activation of NMDA receptors and facilitated the generation of NMDA spikes and axonal action potentials in response to synaptic input. Finally, we show that dynamic regulation of spine neck geometry can preserve local EPSP properties following plasticity-driven changes in synaptic strength, but is inefficient in modifying the amplitude of EPSPs in other cellular compartments. These observations suggest that one function of dendritic spines is to standardize local EPSP properties throughout the dendritic tree, thereby allowing neurons to use similar voltage-sensitive postsynaptic mechanisms at all dendritic locations.

  6. Synaptic activation of ribosomal protein S6 phosphorylation occurs locally in activated dendritic domains.

    Science.gov (United States)

    Pirbhoy, Patricia Salgado; Farris, Shannon; Steward, Oswald

    2016-06-01

    Previous studies have shown that induction of long-term potentiation (LTP) induces phosphorylation of ribosomal protein S6 (rpS6) in postsynaptic neurons, but the functional significance of rpS6 phosphorylation is poorly understood. Here, we show that synaptic stimulation that induces perforant path LTP triggers phosphorylation of rpS6 (p-rpS6) locally near active synapses. Using antibodies specific for phosphorylation at different sites (ser235/236 versus ser240/244), we show that strong synaptic activation led to dramatic increases in immunostaining throughout postsynaptic neurons with selectively higher staining for p-ser235/236 in the activated dendritic lamina. Following LTP induction, phosphorylation at ser235/236 was detectable by 5 min, peaked at 30 min, and was maintained for hours. Phosphorylation at both sites was completely blocked by local infusion of the NMDA receptor antagonist, APV. Despite robust induction of p-rpS6 following high frequency stimulation, assessment of protein synthesis by autoradiography revealed no detectable increases. Exploration of a novel environment led to increases in the number of p-rpS6-positive neurons throughout the forebrain in a pattern reminiscent of immediate early gene induction and many individual neurons that were p-rpS6-positive coexpressed Arc protein. Our results constrain hypotheses about the possible role of rpS6 phosphorylation in regulating postsynaptic protein synthesis during induction of synaptic plasticity.

  7. Antigen-activated dendritic cells ameliorate influenza A infections

    Science.gov (United States)

    Boonnak, Kobporn; Vogel, Leatrice; Orandle, Marlene; Zimmerman, Daniel; Talor, Eyal; Subbarao, Kanta

    2013-01-01

    Influenza A viruses cause significant morbidity and mortality worldwide. There is a need for alternative or adjunct therapies, as resistance to currently used antiviral drugs is emerging rapidly. We tested ligand epitope antigen presentation system (LEAPS) technology as a new immune-based treatment for influenza virus infection in a mouse model. Influenza-J-LEAPS peptides were synthesized by conjugating the binding ligand derived from the β2-microglobulin chain of the human MHC class I molecule (J-LEAPS) with 15 to 30 amino acid–long peptides derived from influenza virus NP, M, or HA proteins. DCs were stimulated with influenza-J-LEAPS peptides (influenza-J-LEAPS) and injected intravenously into infected mice. Antigen-specific LEAPS-stimulated DCs were effective in reducing influenza virus replication in the lungs and enhancing survival of infected animals. Additionally, they augmented influenza-specific T cell responses in the lungs and reduced the severity of disease by limiting excessive cytokine responses, which are known to contribute to morbidity and mortality following influenza virus infection. Our data demonstrate that influenza-J-LEAPS–pulsed DCs reduce virus replication in the lungs, enhance survival, and modulate the protective immune responses that eliminate the virus while preventing excessive cytokines that could injure the host. This approach shows promise as an adjunct to antiviral treatment of influenza virus infections. PMID:23934125

  8. Activity-dependent dendritic spine neck changes are correlated with synaptic strength.

    Science.gov (United States)

    Araya, Roberto; Vogels, Tim P; Yuste, Rafael

    2014-07-15

    Most excitatory inputs in the mammalian brain are made on dendritic spines, rather than on dendritic shafts. Spines compartmentalize calcium, and this biochemical isolation can underlie input-specific synaptic plasticity, providing a raison d'etre for spines. However, recent results indicate that the spine can experience a membrane potential different from that in the parent dendrite, as though the spine neck electrically isolated the spine. Here we use two-photon calcium imaging of mouse neocortical pyramidal neurons to analyze the correlation between the morphologies of spines activated under minimal synaptic stimulation and the excitatory postsynaptic potentials they generate. We find that excitatory postsynaptic potential amplitudes are inversely correlated with spine neck lengths. Furthermore, a spike timing-dependent plasticity protocol, in which two-photon glutamate uncaging over a spine is paired with postsynaptic spikes, produces rapid shrinkage of the spine neck and concomitant increases in the amplitude of the evoked spine potentials. Using numerical simulations, we explore the parameter regimes for the spine neck resistance and synaptic conductance changes necessary to explain our observations. Our data, directly correlating synaptic and morphological plasticity, imply that long-necked spines have small or negligible somatic voltage contributions, but that, upon synaptic stimulation paired with postsynaptic activity, they can shorten their necks and increase synaptic efficacy, thus changing the input/output gain of pyramidal neurons.

  9. Fluorescent dendritic organogels based on 2-(2'-hydroxyphenyl)benzoxazole: emission enhancement and multiple stimuli-responsive properties.

    Science.gov (United States)

    Chen, Hui; Feng, Yu; Deng, Guo-Jun; Liu, Zhi-Xiong; He, Yan-Mei; Fan, Qing-Hua

    2015-07-27

    A new highly efficient and versatile poly(benzyl ether) dendritic organogelator HPB-G1 with 2-(2'-hydroxyphenyl)benzoxazole (HPB) at the focal point has been designed and synthesized. HPB-G1 can form stable organogels toward various apolar and polar organic solvents. Further studies revealed that intermolecular multiple π-π stacking interactions are the main driving forces for the formation of the organogels. Notably, dendron HPB-G1 exhibited a significantly enhanced emission in the gel state in contrast to weak emission in solution. Most interestingly, these dendritic organogels exhibited multiple stimuli-responsive behaviors upon exposure to environmental stimuli, including temperature, sonication, shear stress, and the presence of anions, metal cations, acids/bases, thus leading to reversible sol-gel phase transitions.

  10. Dendritic Cells Enhance HIV Infection of Memory CD4(+) T Cells in Human Lymphoid Tissues.

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    Reyes-Rodriguez, Angel L; Reuter, Morgan A; McDonald, David

    2016-02-01

    Dendritic cells (DCs) play a key role in controlling infections by coordinating innate and adaptive immune responses to invading pathogens. Paradoxically, DCs can increase HIV-1 dissemination in vitro by binding and transferring infectious virions to CD4(+) T cells, a process called transinfection. Transinfection has been well characterized in cultured cell lines and circulating primary T cells, but it is unknown whether DCs enhance infection of CD4(+) T cells in vivo. In untreated HIV infection, massive CD4(+) T-cell infection and depletion occur in secondary lymphoid tissues long before decline is evident in the peripheral circulation. To study the role of DCs in HIV infection of lymphoid tissues, we utilized human tonsil tissues, cultured either as tissue blocks or as aggregate suspension cultures, in single-round infection experiments. In these experiments, addition of monocyte-derived DCs (MDDCs) to the cultures increased T-cell infection, particularly in CD4(+) T cells expressing lower levels of HLA-DR. Subset analysis demonstrated that MDDCs increased HIV-1 infection of central and effector memory T-cell populations. Depletion of endogenous myeloid DCs (myDCs) from the cultures decreased memory T-cell infection, and readdition of MDDCs restored infection to predepletion levels. Using an HIV-1 fusion assay, we found that MDDCs equally increased HIV delivery into naïve, central, and effector memory T cells in the cultures, whereas predepletion of myDCs reduced fusion into memory T cells. Together, these data suggest that resident myDCs facilitate memory T-cell infection in lymphoid tissues, implicating DC-mediated transinfection in driving HIV dissemination within these tissues in untreated HIV/AIDS.

  11. IRX-2, a novel immunotherapeutic, enhances functions of human dendritic cells.

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    Bastian Schilling

    Full Text Available BACKGROUND: In a recent phase II clinical trial for HNSCC patients, IRX-2, a cell-derived biologic, promoted T-cell infiltration into the tumor and prolonged overall survival. Mechanisms responsible for these IRX-2-mediated effects are unknown. We hypothesized that IRX-2 enhanced tumor antigen-(TA-specific immunity by up-regulating functions of dendritic cells (DC. METHODOLOGY/PRINCIPAL FINDINGS: Monocyte-derived DC obtained from 18 HNSCC patients and 12 healthy donors were matured using IRX-2 or a mix of TNF-α, IL-1β and IL-6 ("conv. mix". Multicolor flow cytometry was used to study the DC phenotype and antigen processing machinery (APM component expression. ELISPOT and cytotoxicity assays were used to evaluate tumor-reactive cytotoxic T lymphocytes (CTL. IL-12p70 and IL-10 production by DC was measured by Luminex® and DC migration toward CCL21 was tested in transwell migration assays. IRX-2-matured DC functions were compared with those of conv. mix-matured DC. IRX-2-matured DC expressed higher levels (p<0.05 of CD11c, CD40, CCR7 as well as LMP2, TAP1, TAP2 and tapasin than conv. mix-matured DC. IRX-2-matured DC migrated significantly better towards CCL21, produced more IL-12p70 and had a higher IL12p70/IL-10 ratio than conv. mix-matured DC (p<0.05 for all. IRX-2-matured DC carried a higher density of tumor antigen-derived peptides, and CTL primed with these DC mediated higher cytotoxicity against tumor targets (p<0.05 compared to the conv. mix-matured DC. CONCLUSION: Excellent ability of IRX-2 to induce ex vivo DC maturation in HNSCC patients explains, in part, its clinical benefits and emphasizes its utility in ex vivo maturation of DC generated for therapy.

  12. Examination of MARCO activity on dendritic cell phenotype and function using a gene knockout mouse.

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    Hiroshi Komine

    Full Text Available We have reported the upregulation of MARCO, a member of the class A scavenger receptor family, on the surface of murine and human dendritic cells (DCs pulsed with tumor lysates. Exposure of murine tumor lysate-pulsed DCs to an anti-MARCO antibody led to loss of dendritic-like processes and enhanced migratory capacity. In this study, we have further examined the biological and therapeutic implications of MARCO expression by DCs. DCs generated from the bone marrow (bm of MARCO knockout (MARCO⁻/⁻ mice were phenotypically similar to DCs generated from the bm of wild-type mice and produced normal levels of IL-12 and TNF-α when exposed to LPS. MARCO⁻/⁻ DCs demonstrated enhanced migratory capacity in response to CCL-21 in vitro. After subcutaneous injection into mice, MARCO⁻/⁻ TP-DCs migrated more efficiently to the draining lymph node leading to enhanced generation of tumor-specific IFN-γ producing T cells and improved tumor regression and survival in B16 melanoma-bearing mice. These results support targeting MARCO on the surface of DCs to improve trafficking and induction of anti-tumor immunity.

  13. Differential activation of dendritic cells by Mycobacterium tuberculosis Beijing genotype.

    Science.gov (United States)

    Reyes-Martínez, Juana Elizabeth; Nieto-Patlán, Erik; Nieto-Patlán, Alejandro; Gonzaga-Bernachi, Job; Santos-Mendoza, Teresa; Serafín-López, Jeanet; Chávez-Blanco, Alma; Sandoval-Montes, Claudia; Flores-Romo, Leopoldo; Estrada-Parra, Sergio; Estrada-García, Iris; Chacón-Salinas, Rommel

    2014-01-01

    Mycobacterium tuberculosis (Mtb) inhibits dendritric cells (DC) function in order to delay T cell response. Furthermore, there is increasing evidence that genetic diversity of Mtb strains can affect their interaction with the immune system. Beijing genotype has attracted attention because of its high prevalence and multi-drug resistance. Although it is known that this genotype is hypervirulent and differentially activates macrophages when compared to other genotypes, little is known about its interaction with DC. In order to address this issue, murine bone marrow derived DC (BMDC) were stimulated with soluble extracts (SE) from BCG, H37Rv, Canetti and Beijing genotypes. We observed that unlike other mycobacteria strains, SE-Beijing was unable to induce maturation of DC as assessed by cell surface MHC-II expression. DC stimulated with SE-Beijing failed to produce IL-12 and TNF-α, but did secrete IL-10. Interestingly, SE-Beijing induced CCR7 and PDL-1 on BMDC, but did not induce the expression of CD86. When BMDC stimulated with SE-Beijing were used to activate CD4+ cells they were unable to induce a Th1 response when compared with less virulent genotypes. These results indicate that Beijing is able to modulate DC activation and function, which may be related to the pathogenesis induced by this genotype.

  14. Stabilization of dendritic spine clusters and hyperactive Ras-MAPK signaling predict enhanced motor learning in an autistic savant mouse model

    Directory of Open Access Journals (Sweden)

    Ryan Thomas Ash

    2014-03-01

    Full Text Available That both prominent behavioral inflexibility and exceptional learning abilities are seen occasionally in autistic patients is a mystery. We hypothesize that these altered patterns of learning and memory can arise from a pathological imbalance between the stability and plasticity of internal neural representations. We evaluated this hypothesis in the mouse model of MECP2 duplication syndrome, which demonstrates enhanced motor learning, stereotyped behaviors, and social avoidance. Learning-associated structural plasticity was measured in the motor cortex of MECP2 duplication mice by 2-photon imaging (Fig. 1A. An increased stabilization rate of learning-associated dendritic spines was observed in mutants, and this correlated with rotarod performance. Analysis of the spatial distribution of stabilized spines revealed that the mutant’s increased spine stabilization was due to a specific increase in the stability of spines jointly formed in ~9-micron clusters. Clustered spine stabilization but not isolated spine stabilization predicted enhanced motor performance in MECP2 duplication mice (Fig. 1B. Biochemical assays of Ras-MAPK and mTOR pathway activation demonstrated profound hyperphosphorylation of MAPK in the motor cortex of MECP2 duplication mice with motor training (Fig. 1C. Taken together these data suggest that a pathological bias towards hyperstability of learning-associated dendritic spine clusters driven by hyperactive Ras-MAPK signaling could contribute to neurobehavioral phenotypes in this form of syndromic autism.

  15. Natural amines inhibit activation of human plasmacytoid dendritic cells through CXCR4 engagement

    Science.gov (United States)

    Smith, Nikaïa; Pietrancosta, Nicolas; Davidson, Sophia; Dutrieux, Jacques; Chauveau, Lise; Cutolo, Pasquale; Dy, Michel; Scott-Algara, Daniel; Manoury, Bénédicte; Zirafi, Onofrio; McCort-Tranchepain, Isabelle; Durroux, Thierry; Bachelerie, Françoise; Schwartz, Olivier; Münch, Jan; Wack, Andreas; Nisole, Sébastien; Herbeuval, Jean-Philippe

    2017-01-01

    Plasmacytoid dendritic cells (pDC) are specialized in secretion of type I interferon in response to pathogens. Here we show that natural monoamines and synthetic amines inhibit pDC activation by RNA viruses. Furthermore, a synthetic analogue of histamine reduces type I interferon production in a mouse model of influenza infection. We identify CXC chemokine receptor 4 (CXCR4) as a receptor used by amines to inhibit pDC. Our study establishes a functional link between natural amines and the innate immune system and identifies CXCR4 as a potential ‘on-off' switch of pDC activity with therapeutic potential. PMID:28181493

  16. p38 Mitogen-Activated Protein Kinase in beryllium-induced dendritic cell activation.

    Science.gov (United States)

    Li, L; Huang, Z; Gillespie, M; Mroz, P M; Maier, L A

    2014-12-01

    Dendritic cells (DC) play a role in the regulation of immune responses to haptens, which in turn impact DC maturation. Whether beryllium (Be) is able to induce DC maturation and if this occurs via the MAPK pathway is not known. Primary monocyte-derived DCs (moDCs) models were generated from Be non-exposed healthy volunteers as a non-sensitized cell model, while PBMCs from BeS (Be sensitized) and CBD (chronic beryllium disease) were used as disease models. The response of these cells to Be was evaluated. The expression of CD40 was increased significantly (pBeSO₄-stimulation. BeSO₄ induced p38MAPK phosphorylation, while IκB-α was degraded in Be-stimulated moDCs. The p38 MAPK inhibitor SB203580 blocked Be-induced NF-κB activation in moDCs, suggesting that p38MAPK and NF-κB are dependently activated by BeSO₄. Furthermore, in BeS and CBD subjects, SB203580 downregulated Be-stimulated proliferation in a dose-dependent manner, and decreased Be-stimulated TNF-α and IFNγ cytokine production. Taken together, this study suggests that Be-induces non-sensitized Glu69+ DCs maturation, and that p38MAPK signaling is important in the Be-stimulated DCs activation as well as subsequent T cell proliferation and cytokine production in BeS and CBD. In total, the MAPK pathway may serve as a potential therapeutic target for human granulomatous lung diseases.

  17. Control of Ca2+ Influx and Calmodulin Activation by SK-Channels in Dendritic Spines.

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    Thom Griffith

    2016-05-01

    Full Text Available The key trigger for Hebbian synaptic plasticity is influx of Ca2+ into postsynaptic dendritic spines. The magnitude of [Ca2+] increase caused by NMDA-receptor (NMDAR and voltage-gated Ca2+ -channel (VGCC activation is thought to determine both the amplitude and direction of synaptic plasticity by differential activation of Ca2+ -sensitive enzymes such as calmodulin. Ca2+ influx is negatively regulated by Ca2+ -activated K+ channels (SK-channels which are in turn inhibited by neuromodulators such as acetylcholine. However, the precise mechanisms by which SK-channels control the induction of synaptic plasticity remain unclear. Using a 3-dimensional model of Ca2+ and calmodulin dynamics within an idealised, but biophysically-plausible, dendritic spine, we show that SK-channels regulate calmodulin activation specifically during neuron-firing patterns associated with induction of spike timing-dependent plasticity. SK-channel activation and the subsequent reduction in Ca2+ influx through NMDARs and L-type VGCCs results in an order of magnitude decrease in calmodulin (CaM activation, providing a mechanism for the effective gating of synaptic plasticity induction. This provides a common mechanism for the regulation of synaptic plasticity by neuromodulators.

  18. Multi-Block Enhancement for Lagrangian Dendritic Mesh setup in Altair5

    Energy Technology Data Exchange (ETDEWEB)

    Douglass, Rodney W [Los Alamos National Laboratory

    2010-12-15

    Initial mesh setup for an ASC mUlti-physics code at LANL is done using Altair5. Altair5 assumes that the final mesh is composed of logical structured mesh blocks linked together at mesh boundaries to form, ultimately, an unstructured mesh. Within these blocks, meshes may have dendrites, that is, local regions where two zones share common edges (in two-dimensions, or faces in three-dimensions) with a single zone. In many cases, contiguous subsets of the initial set of blocks may have the same material assigned to them, but without smoothing the mesh would form a computationally challenging initial mesh. Some of these blocks may also have zones with nodes on domain boundaries. This paper reports on the implementation of multiblock smoothing in Altair5, which allows for dendrites and for moving boundary nodes. Dendritic nodes are constrained to be located at the average of their neighbor nodes while boundary nodes are constrained to move along the boundary geometry. Two fundamentally different smoothing methods were implemented. First, a variational principle is presented that balances zonal size and distortion via a user selected weighting with constraints imposed using penalty methods for dendritic nodes and Lagrange multipliers for boundary nodes. Second, the Laplace-Beltrami smoother is presented. This is a general elliptic smoother which can easily be modified to give Laplacian and Winslow-Crowley mesh smoothing. Results are shown for several test meshes of interest.

  19. Reelin Supplementation Enhances Cognitive Ability, Synaptic Plasticity, and Dendritic Spine Density

    Science.gov (United States)

    Rogers, Justin T.; Rusiana, Ian; Trotter, Justin; Zhao, Lisa; Donaldson, Erika; Pak, Daniel T.S.; Babus, Lenard W.; Peters, Melinda; Banko, Jessica L.; Chavis, Pascale; Rebeck, G. William; Hoe, Hyang-Sook; Weeber, Edwin J.

    2011-01-01

    Apolipoprotein receptors belong to an evolutionarily conserved surface receptor family that has intimate roles in the modulation of synaptic plasticity and is necessary for proper hippocampal-dependent memory formation. The known lipoprotein receptor ligand Reelin is important for normal synaptic plasticity, dendritic morphology, and cognitive…

  20. 17beta-estradiol enhances the response of plasmacytoid dendritic cell to CpG.

    Directory of Open Access Journals (Sweden)

    Xiaoxi Li

    Full Text Available Gender differences in immune capabilities suggest that sex hormones such as estrogens were involved in the regulation of the immunocompetence. Numerous studies also suggest that plasmacytoid dendritic cells (PDCs play a pathogenic role in SLE. However, it is unclear whether estrogen can modulate the function of PDCs to influence the development of SLE. In the present study, PDCs from murine spleens were treated with 17beta-estradiol (E2 and CpG respectively or both in vitro, then cell viability, costimulatory molecule expression, cytokine secretion of PDCs, as well as stimulatory capacity of PDCs to B cells were analyzed. Results showed that E2 and CpG increased the cell viability and costimulatory molecule expression on PDCs synergistically. Moreover, the intracellular and extracellular secretion of IFN-alpha was increased by E2 or E2 plus CpG. In addition, E2 and CpG also increased the stimulatory capacity of PDCs to B cells, and the viability of B cells was decreased after neutralizing IFN-alpha significantly. In the experiments in vivo, mice received daily s.c. injections of E2 and CpG respectively or both, then we found that the plasma concentration of IgM were elevated by E2 and CpG synergistically and the expression of IFN-alpha/beta in spleens were noticeably increased by CpG plus E2 compared with the treatment of E2 or CpG only. This study indicates that E2 could exacerbate PDCs' activation with CpG, which further activates B cells to upregulate susceptibility to autoantigens. IFN-alpha plays an important role in the stimulatory effect of PDCs on B cells. E2 stimulation of IFN-alpha production may result in female prevalence in autoimmune diseases such as SLE through activation of PDCs. This study provides novel evidence of relationship between estrogen and SLE and also sheds light on gender biases among SLE patients.

  1. The microtubule-depolymerizing agent ansamitocin P3 programs dendritic cells toward enhanced anti-tumor immunity.

    Science.gov (United States)

    Martin, Kea; Müller, Philipp; Schreiner, Jens; Prince, Spasenija Savic; Lardinois, Didier; Heinzelmann-Schwarz, Viola A; Thommen, Daniela S; Zippelius, Alfred

    2014-09-01

    In addition to direct tumor cell cytotoxicity, chemotherapy can mediate tumor reduction through immune modulation of the tumor microenvironment to promote anti-tumor immunity. Mature dendritic cells (DCs) play key roles in priming robust immune responses in tumor-bearing hosts. Here, we screened a panel of 21 anticancer agents with defined molecular targets for their ability to induce direct maturation of DCs. We identified ansamitocin P3, a microtubule-depolymerizing agent, as a potent inducer of phenotypic and functional maturation of DCs. Exposure of both murine spleen-derived and human monocyte-derived DCs to ansamitocin P3 triggered up-regulation of maturation markers and production of pro-inflammatory cytokines, resulting in an enhanced T cell stimulatory capacity. Local administration of ansamitocin P3 induced maturation of skin Langerhans cells in vivo and promoted antigen uptake and extensive homing of tumor-resident DCs to tumor-draining lymph nodes. When used as an adjuvant in a specific vaccination approach, ansamitocin P3 dramatically increased activation of antigen-specific T cells. Finally, we demonstrate that ansamitocin P3, due to its immunomodulatory properties, acts in synergy with antibody-mediated blockade of the T cell inhibitory receptors PD-1 and CTLA-4. The combination treatment was most effective and induced durable growth inhibition of established tumors. Mechanistically, we observed a reduced regulatory T cell frequency and improved T cell effector function at the tumor site. Taken together, our study unravels an immune-based anti-tumor mechanism exploited by microtubule-depolymerizing agents, including ansamitocin P3, and paves the way for future clinical trials combining this class of agents with immunotherapy.

  2. Protease-activated receptor 2 activation of myeloid dendritic cells regulates allergic airway inflammation

    Directory of Open Access Journals (Sweden)

    Dienger Krista

    2011-09-01

    Full Text Available Abstract Background A common characteristic of allergens is that they contain proteases that can activate protease-activated receptor (PAR-2; however the mechanism by which PAR-2 regulates allergic airway inflammation is unclear. Methods Mice (wild type and PAR-2-deficient were sensitized using German cockroach (GC feces (frass, the isolated protease from GC frass, or through adoptive transfer of GC frass-treated bone marrow-derived dendritic cells (BMDC and measurements of airway inflammation (cellular infiltration, cytokine expression, and mucin production, serum IgE levels and airway hyperresponsiveness (AHR were assessed. BMDC were cultured, treated with GC frass and assessed for cytokine production. PAR-2 expression on pulmonary mDCs was determined by flow cytometry. Results Exposure to GC frass induced AHR and airway inflammation in wild type mice; however PAR-2-deficient mice had significantly attenuated responses. To directly investigate the role of the protease, we isolated the protease from GC frass and administered the endotoxin-free protease into the airways of mice in the presence of OVA. GC frass proteases were sufficient to promote the development of AHR, serum IgE, and Th2 cytokine production. PAR-2 expression on mDC was upregulated following GC frass exposure, but the presence of a functional PAR-2 did not alter antigen uptake. To determine if PAR-2 activation led to differential cytokine production, we cultured BMDC in the presence of GM-CSF and treated these cells ex vivo with GC frass. PAR-2-deficient BMDC released significantly less IL-6, IL-23 and TNFα compared to BMDC from wild type mice, suggesting PAR-2 activation was important in Th2/Th17 skewing cytokine production. To determine the role for PAR-2 on mDCs on the initiation of allergic airway inflammation, BMDCs from wild type and PAR-2-deficient mice were treated in the presence or absence of GC frass and then adoptively transferred into the airway of wild type mice

  3. Bifidobacterium bifidum Actively Changes the Gene Expression Profile Induced by Lactobacillus acidophilus in Murine Dendritic Cells

    DEFF Research Database (Denmark)

    Weiss, Gudrun Margarethe; Rasmussen, Simon; Fink, Lisbeth Nielsen;

    2010-01-01

    Dendritic cells (DC) play a pivotal regulatory role in activation of both the innate as well as the adaptive immune system by responding to environmental microorganisms. We have previously shown that Lactobacillus acidophilus induces a strong production of the pro-inflammatory and Th1 polarizing...... cytokine IL-12 in DC, whereas bifidobacteria do not induce IL-12 but inhibit the IL-12 production induced by lactobacilli. In the present study, genome-wide microarrays were used to investigate the gene expression pattern of murine DC stimulated with Lactobacillus acidophilus NCFM and Bifidobacterium...

  4. Cdc42-dependent actin dynamics controls maturation and secretory activity of dendritic cells

    DEFF Research Database (Denmark)

    Schulz, Anna M; Stutte, Susanne; Hogl, Sebastian

    2015-01-01

    Cell division cycle 42 (Cdc42) is a member of the Rho guanosine triphosphatase family and has pivotal functions in actin organization, cell migration, and proliferation. To further study the molecular mechanisms of dendritic cell (DC) regulation by Cdc42, we used Cdc42-deficient DCs. Cdc42...... disruption, our results propose that Cdc42 control of actin dynamics keeps DCs in an immature state, and cessation of Cdc42 activity during DC maturation facilitates secretion as well as rapid up-regulation of intracellular molecules to the cell surface....

  5. Systemic LPS Translocation Activates Cross-Presenting Dendritic Cells but Is Dispensable for the Breakdown of CD8+ T Cell Peripheral Tolerance in Irradiated Mice.

    Science.gov (United States)

    Espinosa-Carrasco, Gabriel; Villard, Marine; Le Saout, Cecile; Louis-Plence, Pascale; Vicente, Rita; Hernandez, Javier

    2015-01-01

    Lymphodepletion is currently used to enhance the efficacy of cytotoxic T lymphocyte adoptive transfer immunotherapy against cancer. This beneficial effect of conditioning regimens is due, at least in part, to promoting the breakdown of peripheral CD8+ T cell tolerance. Lymphodepletion by total body irradiation induces systemic translocation of commensal bacteria LPS from the gastrointestinal tract. Since LPS is a potent activator of the innate immune system, including antigen presenting dendritic cells, we hypothesized that LPS translocation could be required for the breakdown of peripheral tolerance observed in irradiated mice. To address this issue, we have treated irradiated mice with antibiotics in order to prevent LPS translocation and utilized them in T cell adoptive transfer experiments. Surprisingly, we found that despite of completely blocking LPS translocation into the bloodstream, antibiotic treatment did not prevent the breakdown of peripheral tolerance. Although irradiation induced the activation of cross-presenting CD8+ dendritic cells in the lymphoid tissue, LPS could not solely account for this effect. Activation of dendritic cells by mechanisms other than LPS translocation is sufficient to promote the differentiation of potentially autoreactive CD8+ T cells into effectors in irradiated mice. Our data indicate that LPS translocation is dispensable for the breakdown of CD8+ T cell tolerance in irradiated mice.

  6. Systemic LPS Translocation Activates Cross-Presenting Dendritic Cells but Is Dispensable for the Breakdown of CD8+ T Cell Peripheral Tolerance in Irradiated Mice.

    Directory of Open Access Journals (Sweden)

    Gabriel Espinosa-Carrasco

    Full Text Available Lymphodepletion is currently used to enhance the efficacy of cytotoxic T lymphocyte adoptive transfer immunotherapy against cancer. This beneficial effect of conditioning regimens is due, at least in part, to promoting the breakdown of peripheral CD8+ T cell tolerance. Lymphodepletion by total body irradiation induces systemic translocation of commensal bacteria LPS from the gastrointestinal tract. Since LPS is a potent activator of the innate immune system, including antigen presenting dendritic cells, we hypothesized that LPS translocation could be required for the breakdown of peripheral tolerance observed in irradiated mice. To address this issue, we have treated irradiated mice with antibiotics in order to prevent LPS translocation and utilized them in T cell adoptive transfer experiments. Surprisingly, we found that despite of completely blocking LPS translocation into the bloodstream, antibiotic treatment did not prevent the breakdown of peripheral tolerance. Although irradiation induced the activation of cross-presenting CD8+ dendritic cells in the lymphoid tissue, LPS could not solely account for this effect. Activation of dendritic cells by mechanisms other than LPS translocation is sufficient to promote the differentiation of potentially autoreactive CD8+ T cells into effectors in irradiated mice. Our data indicate that LPS translocation is dispensable for the breakdown of CD8+ T cell tolerance in irradiated mice.

  7. Cytotoxic activity of interferon alpha induced dendritic cells as a biomarker of glioblastoma

    Science.gov (United States)

    Mishinov, S. V.; Stupak, V. V.; Tyrinova, T. V.; Leplina, O. Yu.; Ostanin, A. A.; Chernykh, E. R.

    2016-08-01

    Dendritic cells (DCs) are the most potent antigen presenting cells that can play direct role in anti-tumor immune response as killer cells. DC tumoricidal activity can be stimulated greatly by type I IFN (IFNα and IFNβ). In the present study, we examined cytostatic and cytotoxic activity of monocyte-derived IFNα-induced DCs generated from patients with brain glioma and evaluated the potential use of these parameters in diagnostics of high-grade gliomas. Herein, we demonstrated that patient DCs do not possess the ability to inhibit the growth of tumor HEp-2 cell line but low-grade and high-grade glioma patients do not differ significantly in DC cytostatic activity. However, glioma patient DCs are characterized by reduced cytotoxic activity against HEp-2 cells. The impairment of DC cytotoxic function is observed mainly in glioblastoma patients. The cytotoxic activity of DCs against HEp-2 cells below 9% is an informative marker for glioblastomas.

  8. Notch ligand delta-like 4-pretreated dendritic cells alleviate allergic airway responses by enhancing IL-10 production.

    Directory of Open Access Journals (Sweden)

    Huei-Mei Huang

    Full Text Available The Notch pathway plays a role in the processes of cell proliferation, differentiation, and apoptosis, which affect the development and function of various organs. Dendritic cells (DCs, as professional antigen-presenting cells (APCs, induce T cell activation and promote T cell differentiation by antigen stimulation. Research has shown that Notch ligand delta-like 4 (Dll4 in APCs is associated with stimulation of a Th1-type response. However, the regulatory roles of Dll4 in the activation and function of DCs have yet to be clearly elucidated. In this study, we demonstrated that activation of Dll4-pretreated bone marrow-derived DCs by performing ovalbumin (OVA stimulation expressed a high level of interleukin (IL-10 without diminishing IL-12 production. By contrast, the proinflammatory cytokines, IL-1β, IL-6, and tumor necrosis factor (TNF-α, decreased in Dll4-pretreated DCs by performing either lipopolysaccharide (LPS or OVA stimulation. Compared to fully mature DCs, lower levels of MHC class II CD40 and higher levels of CD80 and CD86 molecules were expressed in these semi-mature like DCs. Dll4 Notch signaling also enhanced Notch ligand mRNA expression of Dll1, Dll4, and Jagged1 in DCs. Dll4-modified DCs exhibited a reduced capacity to stimulate the proliferation of OVA-specific CD4(+ T cells, but actively promoted large amounts of IL-10 production in these activated T cells. Furthermore, immunomodulatory effects of Dll4-modified DCs were examined in an established asthmatic animal model. After adoptive transfer of OVA-pulsed plus Dll4-pretreated DCs in OVA-immunized mice, OVA challenge induced lower OVA-specific immunoglobulin E (IgE and higher IgG2a antibody production, lower eotaxin, keratinocyte-derived chemokine (KC, IL-5, and IL-13 release in bronchial alveolar lavage fluid, attenuated airway hyper-responsiveness, and promoted higher IL-10 and interferon (IFN-γ production in the spleen. In summary, our findings elucidate the new role of

  9. HuD interacts with Bdnf mRNA and is essential for activity-induced BDNF synthesis in dendrites.

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    Filip Vanevski

    Full Text Available Highly specific activity-dependent neuronal responses are necessary for modulating synapses to facilitate learning and memory. We present evidence linking a number of important processes involved in regulating synaptic plasticity, suggesting a mechanistic pathway whereby activity-dependent signaling, likely through protein kinase C (PKC-mediated phosphorylation of HuD, can relieve basal repression of Bdnf mRNA translation in dendrites, allowing for increased TrkB signaling and synaptic remodeling. We demonstrate that the neuronal ELAV family of RNA binding proteins associates in vivo with several Bdnf mRNA isoforms present in the adult brain in an activity-dependent manner, and that one member, HuD, interacts directly with sequences in the long Bdnf 3' untranslated region (3'UTR and co-localizes with Bdnf mRNA in dendrites of hippocampal neurons. Activation of PKC leads to increased dendritic translation of mRNAs containing the long Bdnf 3'UTR, a process that is dependent on the presence of HuD and its phosphorylation at threonine residues 149 and/or 165. Thus, we found a direct effect of HuD on regulating translation of dendritic Bdnf mRNAs to mediate local and activity-dependent increases in dendritic BDNF synthesis.

  10. DC-SCRIPT Regulates IL-10 Production in Human Dendritic Cells by Modulating NF-κBp65 Activation.

    Science.gov (United States)

    Søndergaard, Jonas Nørskov; Poghosyan, Susanna; Hontelez, Saartje; Louche, Pauline; Looman, Maaike W G; Ansems, Marleen; Adema, Gosse J

    2015-08-15

    The balance between tolerance and immunity is important for the outcome of an infection or cancer, and dendritic cells (DCs) are key regulators of this balance. DC-specific transcript (DC-SCRIPT) is a protein expressed by DCs and has been demonstrated to suppress both TLR-mediated expression of IL-10 and glucocorticoid receptor-mediated transcription of glucocorticoid-induced leucine zipper (GILZ). Because GILZ is known to promote IL-10 production, we investigated whether these two processes are linked. Dual-knockdown and inhibition experiments demonstrated that neither GILZ nor glucocorticoid receptor play a role in TLR-induced IL-10 production after DC-SCRIPT knockdown. The NF-κB pathway is another route involved in IL-10 production after DC activation. Strikingly, inhibition of NF-κB led to a decreased TLR-mediated IL-10 production in DC-SCRIPT knockdown DCs. Moreover, DC-SCRIPT knockdown DCs showed enhanced phosphorylation, acetylation, and IL10 enhancer binding of the NF-κB subunit p65. These data demonstrate that besides nuclear receptor regulation, DC-SCRIPT also modulates activation of NF-κBp65 after TLR activation in human DCs.

  11. The 40-year history of modeling active dendrites in cerebellar Purkinje cells: Emergence of the first single cell 'Community Model'

    Directory of Open Access Journals (Sweden)

    James M Bower

    2015-10-01

    Full Text Available The subject of the effects of the active properties of the Purkinje cell dendrite on neuronal function has been an active subject of study for more than 40 years. Somewhat unusually, some of these investigations, from the outset have involved an interacting combination of experimental and model-based techniques. This paper recounts that 40-year history, and the view of the functional significance of the active properties of the Purkinje cell dendrite that has emerged. It specifically considers the emergence from these efforts of what is arguably the first single cell ‘community’ model in neuroscience. The paper also considers the implications of the development of this model for future studies of the complex properties of neuronal dendrites.

  12. Immunostimulatory Effects Triggered by Enterococcus faecalis CECT7121 Probiotic Strain Involve Activation of Dendritic Cells and Interferon-Gamma Production

    Science.gov (United States)

    Molina, Matías Alejandro; Díaz, Ailén Magalí; Hesse, Christina; Ginter, Wiebke; Gentilini, María Virginia; Nuñez, Guillermo Gabriel; Canellada, Andrea Mercedes; Sparwasser, Tim; Berod, Luciana; Castro, Marisa Silvia; Manghi, Marcela Alejandra

    2015-01-01

    Probiotics can modulate the immune system, conferring beneficial effects on the host. Understanding how these microorganisms contribute to improve the health status is still a challenge. Previously, we have demonstrated that Enterococcus faecalis CECT7121 implants itself and persists in the murine gastrointestinal tract, and enhances and skews the profile of cytokines towards the Th1 phenotype in several biological models. Given the importance of dendritic cells (DCs) in the orchestration of immunity, the aim of this work was to elucidate the influence of E. faecalis CECT7121 on DCs and the outcome of the immune responses. In this work we show that E. faecalis CECT7121 induces a strong dose-dependent activation of DCs and secretion of high levels of IL-12, IL-6, TNFα, and IL-10. This stimulation is dependent on TLR signaling, and skews the activation of T cells towards the production of IFNγ. The influence of this activation in the establishment of Th responses in vivo shows the accumulation of specific IFNγ-producing cells. Our findings indicate that the activation exerted by E. faecalis CECT7121 on DCs and its consequence on the cellular adaptive immune response may have broad therapeutic implications in immunomodulation. PMID:25978357

  13. Immunostimulatory Effects Triggered by Enterococcus faecalis CECT7121 Probiotic Strain Involve Activation of Dendritic Cells and Interferon-Gamma Production.

    Directory of Open Access Journals (Sweden)

    Matías Alejandro Molina

    Full Text Available Probiotics can modulate the immune system, conferring beneficial effects on the host. Understanding how these microorganisms contribute to improve the health status is still a challenge. Previously, we have demonstrated that Enterococcus faecalis CECT7121 implants itself and persists in the murine gastrointestinal tract, and enhances and skews the profile of cytokines towards the Th1 phenotype in several biological models. Given the importance of dendritic cells (DCs in the orchestration of immunity, the aim of this work was to elucidate the influence of E. faecalis CECT7121 on DCs and the outcome of the immune responses. In this work we show that E. faecalis CECT7121 induces a strong dose-dependent activation of DCs and secretion of high levels of IL-12, IL-6, TNFα, and IL-10. This stimulation is dependent on TLR signaling, and skews the activation of T cells towards the production of IFNγ. The influence of this activation in the establishment of Th responses in vivo shows the accumulation of specific IFNγ-producing cells. Our findings indicate that the activation exerted by E. faecalis CECT7121 on DCs and its consequence on the cellular adaptive immune response may have broad therapeutic implications in immunomodulation.

  14. Fcγ receptor IIb strongly regulates Fcγ receptor-facilitated T cell activation by dendritic cells

    NARCIS (Netherlands)

    N. van Montfoort (Nadine); P.A.C. 't Hoen (Peter); S.M. Mangsbo (Sara); M. Camps (Marcel); P. Boross (Peter); C.J.M. Melief (Cornelis); F. Ossendorp (Ferry); J.S. Verbeek (Sjef)

    2012-01-01

    textabstractFcγR ligation by Ag-Ab immune complexes (IC) not only mediates effective Ag uptake, but also strongly initiates dendritic cell (DC) maturation, a requirement for effective T cell activation. Besides the activating FcγRI, FcγRIII, and FcγRIV, the inhibitory FcγRIIb is expressed on DCs. It

  15. Antitumor activities of human dendritic cells derived from peripheral and cord blood

    Institute of Scientific and Technical Information of China (English)

    Jin-Kun Zhang; Jun Li; Hai-Bin Chen; Jin-Lun Sun; Yao-Juan Qu; Juan-Juan Lu

    2002-01-01

    AIM: To observe the biological specialization of humanperipheral blood dendritic cells (DC) and cord blood derivedDC and its effects on effector cells killing humanhepatocarcinoma cell line BEL-7402 in vitro.METHODS: The DC biological characteristics were detectedwith immunohistochemical and MTT assay. Two antitumorexperimental groups are: peripheral blood DC and cordblood DC groups. Peripheral blood DC groups used LAKcells as the effector cells and BEL-7402 as target cells, whilecord blood DC groups used CTL induced by tumor antigentwice pulsed DC as effector cells and BEL-7402 as targetcells, additional peripheral blood DC and cord blood DC areadded to observe its stimulating activities to effector cells.The effector's cytotoxicity to tumor cells were detected withneutral red colorimetric assay at two effector/target ratios of5:1 and 10: 1.RESULTS: Peripheral blood DC and cord blood DC highlyexpressed HLA-ABC, HLA-DR, HLA-DQ, CD54 and S-100protein. The stimulating activities to lymphocyteproliferation were compared between experimental groups(DC added) and control group (no DC added). In sixexperiment subgroups, the DC/lymphocyte ratio wassequentially 0.25: 100, 0.5: 100, 1: 100, 2: 100, 4: 100 and 8:100, A values(x± s) were 0.75396± 0.009, 0.84916± 0.010,0.90894± 0.012, 0.98371 ± 0.007, 1.01299 ± 0.006 and 1.20384± 0.006 in peripheral blood DC groups and 0.77650 ± 0.005,0.83008± 0.007, 0.92725 ± 0.007, 1.05990 ± 0.010, 1.15583 ±0.011, 1.22983 ± 0.011 in cord blood DC groups. A value was0.59517 ± 0.005 in control group. The stimulating activitieswere higher in experimental groups than in control group ( P< 0.01 ), which were increased when the DC concentrationwas enlarged ( P < 0.01 ). Two differently derived DCs hadthe same phenotypes and similar stimulating activities ( P >0.05). In peripheral blood DC groups, the cytotoxicity (x ±s) of the LD groups (experimental groups) and L groups(control group) was 58.16% ± 2.03% (5: 1), 46.18% ±2

  16. Ascaris lumbricoides pseudocoelomic body fluid induces a partially activated dendritic cell phenotype with Th2 promoting ability in vivo.

    Science.gov (United States)

    Dowling, David J; Noone, Cariosa M; Adams, Paul N; Vukman, Krisztina V; Molloy, Sile F; Forde, Jessica; Asaolu, Samuel; O'Neill, Sandra M

    2011-02-01

    Dendritic cells (DCs) matured with helminth-derived molecules that promote Th2 immune responses do not follow conventional definitions of DC maturation processes. While a number of models of DC maturation by Th2 stimuli are postulated, further studies are required if we are to clearly define DC maturation processes that lead to Th2 immune responses. In this study, we examine the interaction of Th2-inducing molecules from the parasitic helminth Ascaris lumbricoides with the maturation processes and function of DCs. Here we show that murine bone marrow-derived DCs are partially matured by A. lumbricoides pseudocoelomic body fluid (ABF) as characterised by the production of IL-6, IL-12p40 and macrophage inflammatory protein 2 (MIP-2) but no enhanced expression of cluster of differentiation (CD)-14, T-cell co-stimulatory markers CD80, CD86, CD40, OX40L and major histocompatibility complex class II was observed. Despite these phenotypic characteristics, ABF-stimulated DCs displayed the functional hallmarks of fully matured cells, enhancing DC phagocytosis and promoting Th2-type responses in skin-draining lymph node cells in vivo. ABF activated Th2-associated extracellular signal-regulated kinase-1 and nuclear factor-kB intracellular signalling pathways independently of toll-like receptor 4. Taken together, we believe this is the first paper to demonstrate A. lumbricoides murine DC-Th cell-driven responses shedding further light on DC maturation processes by helminth antigens.

  17. Blocking junctional adhesion molecule C enhances dendritic cell migration and boosts the immune responses against Leishmania major.

    Science.gov (United States)

    Ballet, Romain; Emre, Yalin; Jemelin, Stéphane; Charmoy, Mélanie; Tacchini-Cottier, Fabienne; Imhof, Beat A

    2014-12-01

    The recruitment of dendritic cells to sites of infections and their migration to lymph nodes is fundamental for antigen processing and presentation to T cells. In the present study, we showed that antibody blockade of junctional adhesion molecule C (JAM-C) on endothelial cells removed JAM-C away from junctions and increased vascular permeability after L. major infection. This has multiple consequences on the output of the immune response. In resistant C57BL/6 and susceptible BALB/c mice, we found higher numbers of innate immune cells migrating from blood to the site of infection. The subsequent migration of dendritic cells (DCs) from the skin to the draining lymph node was also improved, thereby boosting the induction of the adaptive immune response. In C57BL/6 mice, JAM-C blockade after L. major injection led to an enhanced IFN-γ dominated T helper 1 (Th1) response with reduced skin lesions and parasite burden. Conversely, anti JAM-C treatment increased the IL-4-driven T helper 2 (Th2) response in BALB/c mice with disease exacerbation. Overall, our results show that JAM-C blockade can finely-tune the innate cell migration and accelerate the consequent immune response to L. major without changing the type of the T helper cell response.

  18. Blocking junctional adhesion molecule C enhances dendritic cell migration and boosts the immune responses against Leishmania major.

    Directory of Open Access Journals (Sweden)

    Romain Ballet

    2014-12-01

    Full Text Available The recruitment of dendritic cells to sites of infections and their migration to lymph nodes is fundamental for antigen processing and presentation to T cells. In the present study, we showed that antibody blockade of junctional adhesion molecule C (JAM-C on endothelial cells removed JAM-C away from junctions and increased vascular permeability after L. major infection. This has multiple consequences on the output of the immune response. In resistant C57BL/6 and susceptible BALB/c mice, we found higher numbers of innate immune cells migrating from blood to the site of infection. The subsequent migration of dendritic cells (DCs from the skin to the draining lymph node was also improved, thereby boosting the induction of the adaptive immune response. In C57BL/6 mice, JAM-C blockade after L. major injection led to an enhanced IFN-γ dominated T helper 1 (Th1 response with reduced skin lesions and parasite burden. Conversely, anti JAM-C treatment increased the IL-4-driven T helper 2 (Th2 response in BALB/c mice with disease exacerbation. Overall, our results show that JAM-C blockade can finely-tune the innate cell migration and accelerate the consequent immune response to L. major without changing the type of the T helper cell response.

  19. Calcium-activated potassium conductances contribute to action potential repolarization at the soma but not the dendrites of hippocampal CA1 pyramidal neurons.

    Science.gov (United States)

    Poolos, N P; Johnston, D

    1999-07-01

    Evidence is accumulating that voltage-gated channels are distributed nonuniformly throughout neurons and that this nonuniformity underlies regional differences in excitability within the single neuron. Previous reports have shown that Ca2+, Na+, A-type K+, and hyperpolarization-activated, mixed cation conductances have varying distributions in hippocampal CA1 pyramidal neurons, with significantly different densities in the apical dendrites compared with the soma. Another important channel mediates the large-conductance Ca2+-activated K+ current (IC), which is responsible in part for repolarization of the action potential (AP) and generation of the afterhyperpolarization that follows the AP recorded at the soma. We have investigated whether this current is activated by APs retrogradely propagating in the dendrites of hippocampal pyramidal neurons using whole-cell dendritic patch-clamp recording techniques. We found no IC activation by back-propagating APs in distal dendritic recordings. Dendritic APs activated IC only in the proximal dendrites, and this activation decayed within the first 100-150 micrometer of distance from the soma. The decay of IC in the proximal dendrites occurred despite AP amplitude, plus presumably AP-induced Ca2+ influx, that was comparable with that at the soma. Thus we conclude that IC activation by action potentials is nonuniform in the hippocampal pyramidal neuron, which may represent a further example of regional differences in neuronal excitability that are determined by the nonuniform distribution of voltage-gated channels in dendrites.

  20. TGF-β suppresses β-catenin-dependent tolerogenic activation program in dendritic cells.

    Directory of Open Access Journals (Sweden)

    Bryan Vander Lugt

    Full Text Available The mechanisms that underlie the critical dendritic cell (DC function in maintainance of peripheral immune tolerance are incompletely understood, although the β-catenin signaling pathway is critical for this role. The molecular details by which β-catenin signaling is regulated in DCs are unknown. Mechanical disruption of murine bone marrow-derived DC (BMDC clusters activates DCs while maintaining their tolerogenic potential and this activation is associated with β-catenin signaling, providing a useful model with which to explore tolerance-associated β-catenin signaling in DCs. In this report, we demonstrate novel molecular features of the signaling events that control DC activation in response to mechanical stimulation. Non-canonical β-catenin signaling is an essential component of this tolerogenic activation and is modulated by adhesion molecules, including integrins. This unique β-catenin-dependent signaling pathway is constitutively active at low levels, suggesting that mechanical stimulation is not necessarily required for induction of this unique activation program. We additionally find that the immunomodulatory cytokine TGF-β antagonizes β-catenin in DCs, thereby selectively suppressing signaling associated with tolerogenic DC activation while having no impact on LPS-induced, β-catenin-independent immunogenic activation. These findings provide new molecular insight into the regulation of a critical signaling pathway for DC function in peripheral immune tolerance.

  1. Lymphocytes in the peritoneum home to the omentum and are activated by resident dendritic cells.

    Science.gov (United States)

    Carlow, Douglas A; Gold, Michael R; Ziltener, Hermann J

    2009-07-15

    The omentum is of interest in the context of obesity-related metabolic disease where adipose tissue exhibits inflammatory changes; however, the immunology of the omentum is underexplored. The greater omentum is draped from the stomach and consists predominantly of adipose tissue studded with lymphoreticular aggregations (milky spots) that distinguish it from other visceral adipose tissues. Milky spots are thought to contain and conduct leukocytes in transit from the blood to the peritoneal cavity, particularly during peritonitis. We show here that both B and T lymphocytes counterflow from the peritoneal cavity to the omentum in mice. Residence in the omentum was brief with a t(1/2) residence time of 6 h. Omentum access was pertussis toxin-sensitive, dependent on activation of the Rap1 GTPase, and on the integrin LFA-1. B cells and CD44(high) T cells accessed the omentum most efficiently, but homing of resting CD44(low) T cells was also observed. Omental tissue from normal healthy mice was found to contain CD8(-)CD11b(high)MHC class II(high)CD11c(high) dendritic cells that promoted the rapid activation of T cells entering the omentum and cross-presented soluble OVA or OVA acquired from either OVA-expressing Escherichia coli or OVA-pulsed spleen cells. We conclude that the omentum incorporates two key features of immunological sentinel function, actively supported lymphocyte traffic and dendritic cells, that reinforce a conceptual framework for function in stimulating adaptive immunity. These results extend basic understanding of omental and peritoneal cavity immunology and of how proinflammatory events occurring within the peritoneal cavity might affect adipocyte and hepatocyte metabolism.

  2. Calmodulin activation by calcium transients in the postsynaptic density of dendritic spines.

    Directory of Open Access Journals (Sweden)

    Daniel X Keller

    Full Text Available The entry of calcium into dendritic spines can trigger a sequence of biochemical reactions that begins with the activation of calmodulin (CaM and ends with long-term changes to synaptic strengths. The degree of activation of CaM can depend on highly local elevations in the concentration of calcium and the duration of transient increases in calcium concentration. Accurate measurement of these local changes in calcium is difficult because the spaces are so small and the numbers of molecules are so low. We have therefore developed a Monte Carlo model of intracellular calcium dynamics within the spine that included calcium binding proteins, calcium transporters and ion channels activated by voltage and glutamate binding. The model reproduced optical recordings using calcium indicator dyes and showed that without the dye the free intracellular calcium concentration transient was much higher than predicted from the fluorescent signal. Excitatory postsynaptic potentials induced large, long-lasting calcium gradients across the postsynaptic density, which activated CaM. When glutamate was released at the synapse 10 ms before an action potential occurred, simulating activity patterns that strengthen hippocampal synapses, the calcium gradient and activation of CaM in the postsynaptic density were much greater than when the order was reversed, a condition that decreases synaptic strengths, suggesting a possible mechanism underlying the induction of long-term changes in synaptic strength. The spatial and temporal mechanisms for selectivity in CaM activation demonstrated here could be used in other signaling pathways.

  3. Regulation of protein synthesis and autophagy in activated dendritic cells: implications for antigen processing and presentation.

    Science.gov (United States)

    Argüello, Rafael J; Reverendo, Marisa; Gatti, Evelina; Pierre, Philippe

    2016-07-01

    Antigenic peptides presented in the context of major histocompatibility complex (MHC) molecules originate from the degradation of both self and non-self proteins. T cells can therefore recognize at the surface of surveyed cells, the self-peptidome produced by the cell itself (mostly inducing tolerance) or immunogenic peptides derived from exogenous origins. The initiation of adaptive immune responses by dendritic cells (DCs), through the antigenic priming of naïve T cells, is associated to microbial pattern recognition receptors engagement. Activation of DCs by microbial product or inflammatory cytokines initiates multiple processes that maximize DC capacity to present exogenous antigens and stimulate T cells by affecting major metabolic and membrane traffic pathways. These include the modulation of protein synthesis, the regulation of MHC and co-stimulatory molecules transport, as well as the regulation of autophagy, that, all together promote exogenous antigen presentation while limiting the display of self-antigens by MHC molecules.

  4. The monoclonal antibody ER-BMDM1 recognizes a macrophage and dendritic cell differentiation antigen with aminopeptidase activity

    NARCIS (Netherlands)

    P.J. Leenen (Pieter); M.L. Melis (Marleen); G. Kraal (Georg); A.T. Hoogeveen (Andre); W. van Ewijk (Willem)

    1992-01-01

    markdownabstractAbstract Here we describe the reactivity of monoclonal antibody (mAb) ER-BMDM1, directed against a 160-kDa cell membrane-associated antigen (Ag) with aminopeptidase activity. The aminopeptidase recognized by ER-BMDM1 is present on various mouse macrophage (MΦ) and dendritic cell (D

  5. Direct Activation of Human Dendritic Cells by Particle-Bound but Not Soluble MHC Class II Ligand

    NARCIS (Netherlands)

    R.B. Baleeiro (Renato); K.H. Wiesmüller (Karl Heinz); L. Dähne (Lars); J. Lademann (Jürgen); J.A. Barbuto (José); P. Walden (Peter)

    2013-01-01

    textabstractDendritic cells (DCs) are key activators of cellular immune responses through their capacity to induce naïve T cells and sustained effector T cell responses. This capacity is a function of their superior efficiency of antigen presentation via MHC class I and class II molecules, and the e

  6. ERK1/2 Activation Is Necessary for BDNF to Increase Dendritic Spine Density in Hippocampal CA1 Pyramidal Neurons

    Science.gov (United States)

    Alonso, Mariana; Medina, Jorge H.; Pozzo-Miller, Lucas

    2004-01-01

    Brain-derived neurotrophic factor (BDNF) is a potent modulator of synaptic transmission and plasticity in the CNS, acting both pre- and postsynaptically. We demonstrated recently that BDNF/TrkB signaling increases dendritic spine density in hippocampal CA1 pyramidal neurons. Here, we tested whether activation of the prominent ERK (MAPK) signaling…

  7. Enhanced plasticity of Zr-based bulk metallic glass composite by in situ formed β-Zr dendritics

    Institute of Scientific and Technical Information of China (English)

    SUN Guoyuan; CHEN Guang; CHEN Guoliang

    2007-01-01

    A Zr56.2Ti13.8Nb5.0Cu6.9Ni5.6Be12.5 bulk metallic glasscomposite with enhanced plasticity by in situ formed bcc β-Zr solid solution was prepared by water quenching.The ductile βphase with a volume fraction of about 30% possesses a developed dendritic morphology.The composite exhibits a pure plastic strain of 10.2% combined with a large elastic strain limit of 2% and a high ultimate strength of 1778 Mpa upon room-temperature compression.Microscopic observa- tion shows numbers of wave-like shear bands distributed on the surface of the compressive samples.

  8. Calcium Transients in Dendrites of Neocortical Neurons Evoked by Single Subthreshold Excitatory Postsynaptic Potentials via Low-Voltage-Activated Calcium Channels

    Science.gov (United States)

    Markram, Henry; Sakmann, Bert

    1994-05-01

    Simultaneous recordings of membrane voltage and concentration of intracellular Ca2+ ([Ca2+]_i) were made in apical dendrites of layer 5 pyramidal cells of rat neocortex after filling dendrites with the fluorescent Ca2+ indicator Calcium Green-1. Subthreshold excitatory postsynaptic potentials (EPSPs), mediated by the activation of glutamate receptor channels, caused a brief increase in dendritic [Ca2+]_i. This rise in dendritic [Ca2+]_i was mediated by the opening of low-voltage-activated Ca2+ channels in the dendritic membrane. The results provide direct evidence that dendrites do not function as passive cables even at low-frequency synaptic activity; rather, a single subthreshold EPSP changes the dendritic membrane conductance by opening Ca2+ channels and generating a [Ca2+]_i transient that may propagate towards the soma. The activation of these Ca2+ channels at a low-voltage threshold is likely to influence the way in which dendritic EPSPs contribute to the electrical activity of the neuron.

  9. Activation of Dendritic Cells by the Novel Toll-Like Receptor 3 Agonist RGC100

    Directory of Open Access Journals (Sweden)

    Kai Naumann

    2013-01-01

    Full Text Available Toll-like receptor (TLR 3 agonists emerged as attractive candidates for vaccination strategies against tumors and pathogens. An important mechanism of action of such agonists is based on the activation of TLR3-expressing dendritic cells (DCs, which display a unique capacity to induce and stimulate T-cell responses. In this context, it has been demonstrated that targeting of TLR3 by double-stranded RNA such as poly(I:C results in potent activation of DCs. Major disadvantages of poly(I:C comprise its undefined chemical structure and very poor homogeneity, with subsequent unpredictable pharmacokinetics and high toxicity. In the present study, we evaluated the physicochemical properties and biological activity of the novel TLR3 agonist RGC100. RGC100 has a defined chemical structure, with a defined length (100 bp and molecular weight (64.9 KDa and a good solubility. RGC100 is stable in serum and activates myeloid DCs through TLR3 targeting, as evidenced by gene silencing experiments. Activation of mouse and human myeloid CD1c+ DCs by RGC100 leads to secretion of several proinflammatory cytokines. In addition, RGC100 improves the ability of CD1c+ DCs to stimulate T-cell proliferation. Due to its physicochemical properties and its immunostimulatory properties, RGC100 may represent a promising adjuvant for prophylactic and therapeutic vaccination strategies.

  10. FOXO1 regulates dendritic cell activity through ICAM-1 and CCR7.

    Science.gov (United States)

    Dong, Guangyu; Wang, Yu; Xiao, Wenmei; Pacios Pujado, Sandra; Xu, Fanxing; Tian, Chen; Xiao, E; Choi, Yongwon; Graves, Dana T

    2015-04-15

    The transcription factor FOXO1 regulates cell function and is expressed in dendritic cells (DCs). We investigated the role of FOXO1 in activating DCs to stimulate a lymphocyte response to bacteria. We show that bacteria induce FOXO1 nuclear localization through the MAPK pathway and demonstrate that FOXO1 is needed for DC activation of lymphocytes in vivo. This occurs through FOXO1 regulation of DC phagocytosis, chemotaxis, and DC-lymphocyte binding. FOXO1 induces DC activity by regulating ICAM-1 and CCR7. FOXO1 binds to the CCR7 and ICAM-1 promoters, stimulates CCR7 and ICAM-1 transcriptional activity, and regulates their expression. This is functionally important because transfection of DCs from FOXO1-deleted CD11c.Cre(+)FOXO1(L/L) mice with an ICAM-1-expressing plasmid rescues the negative effect of FOXO1 deletion on DC bacterial phagocytosis and chemotaxis. Rescue with both CCR7 and ICAM-1 reverses impaired DC homing to lymph nodes in vivo when FOXO1 is deleted. Moreover, Ab production following injection of bacteria is significantly reduced with lineage-specific FOXO1 ablation. Thus, FOXO1 coordinates upregulation of DC activity through key downstream target genes that are needed for DCs to stimulate T and B lymphocytes and generate an Ab defense to bacteria.

  11. Microparticulate β-glucan vaccine conjugates phagocytized by dendritic cells activate both naïve CD4 and CD8 T cells in vitro.

    Science.gov (United States)

    Berner, Vanessa K; duPre, Sally A; Redelman, Doug; Hunter, Kenneth W

    2015-01-01

    Microparticulate β-glucan (MG) conjugated to vaccine antigen has been shown to serve as an effective adjuvant in vivo. To further study antigen presentation by MG:vaccine conjugates, bone marrow-derived dendritic cells (BMDC) were treated with MG conjugated to ovalbumin (OVA), then interacted with splenocytes from DO11.10 transgenic mice expressing an OVA peptide-specific T cell receptor. BMDC treated with MG:OVA induced significantly higher numbers of activated (CD25+CD69+) OVA-specific CD4+ T cells than BMDC treated with OVA alone. BMDC treated with MG:OVA upregulated CD86 and CD40 expression as well as MG alone, indicating that conjugation of OVA does not alter the immunostimulatory capacity of MG. Activation of CD8+ OVA-specific OT-1 cells showed that MG:OVA is also capable of enhancing cross-presentation by BMDC to CD8+ cytotoxic T cells. These results show that MG acts as an adjuvant to enhance antigen presentation by dendritic cells to naïve, antigen-specific CD4 and CD8 T cells.

  12. RAB-10 Regulates Dendritic Branching by Balancing Dendritic Transport.

    Directory of Open Access Journals (Sweden)

    Caitlin A Taylor

    2015-12-01

    Full Text Available The construction of a large dendritic arbor requires robust growth and the precise delivery of membrane and protein cargoes to specific subcellular regions of the developing dendrite. How the microtubule-based vesicular trafficking and sorting systems are regulated to distribute these dendritic development factors throughout the dendrite is not well understood. Here we identify the small GTPase RAB-10 and the exocyst complex as critical regulators of dendrite morphogenesis and patterning in the C. elegans sensory neuron PVD. In rab-10 mutants, PVD dendritic branches are reduced in the posterior region of the cell but are excessive in the distal anterior region of the cell. We also demonstrate that the dendritic branch distribution within PVD depends on the balance between the molecular motors kinesin-1/UNC-116 and dynein, and we propose that RAB-10 regulates dendrite morphology by balancing the activity of these motors to appropriately distribute branching factors, including the transmembrane receptor DMA-1.

  13. Enhanced NIF neutron activation diagnostics.

    Science.gov (United States)

    Yeamans, C B; Bleuel, D L; Bernstein, L A

    2012-10-01

    The NIF neutron activation diagnostic suite relies on removable activation samples, leading to operational inefficiencies and a fundamental lower limit on the half-life of the activated product that can be observed. A neutron diagnostic system measuring activation of permanently installed samples could remove these limitations and significantly enhance overall neutron diagnostic capabilities. The physics and engineering aspects of two proposed systems are considered: one measuring the (89)Zr/(89 m)Zr isomer ratio in the existing Zr activation medium and the other using potassium zirconate as the activation medium. Both proposed systems could improve the signal-to-noise ratio of the current system by at least a factor of 5 and would allow independent measurement of fusion core velocity and fuel areal density.

  14. Toll-Like Receptor-Dependent Immune Complex Activation of B Cells and Dendritic Cells.

    Science.gov (United States)

    Moody, Krishna L; Uccellini, Melissa B; Avalos, Ana M; Marshak-Rothstein, Ann; Viglianti, Gregory A

    2016-01-01

    High titers of autoantibodies reactive with DNA/RNA molecular complexes are characteristic of autoimmune disorders such as systemic lupus erythematosus (SLE). In vitro and in vivo studies have implicated the endosomal Toll-like receptor 9 (TLR9) and Toll-like receptor 7 (TLR7) in the activation of the corresponding autoantibody producing B cells. Importantly, TLR9/TLR7-deficiency results in the inability of autoreactive B cells to proliferate in response to DNA/RNA-associated autoantigens in vitro, and in marked changes in the autoantibody repertoire of autoimmune-prone mice. Uptake of DNA/RNA-associated autoantigen immune complexes (ICs) also leads to activation of dendritic cells (DCs) through TLR9 and TLR7. The initial studies from our lab involved ICs formed by a mixture of autoantibodies and cell debris released from dying cells in culture. To better understand the nature of the mammalian ligands that can effectively activate TLR7 and TLR9, we have developed a methodology for preparing ICs containing defined DNA fragments that recapitulate the immunostimulatory activity of the previous "black box" ICs. As the endosomal TLR7 and TLR9 function optimally from intracellular acidic compartments, we developed a facile methodology to monitor the trafficking of defined DNA ICs by flow cytometry and confocal microscopy. These reagents reveal an important role for nucleic acid sequence, even when the ligand is mammalian DNA and will help illuminate the role of IC trafficking in the response.

  15. A key role for PTP1B in dendritic cell maturation, migration, and T cell activation.

    Science.gov (United States)

    Martin-Granados, Cristina; Prescott, Alan R; Le Sommer, Samantha; Klaska, Izabela P; Yu, Tian; Muckersie, Elizabeth; Giuraniuc, Claudiu V; Grant, Louise; Delibegovic, Mirela; Forrester, John V

    2015-12-01

    Dendritic cells (DC) are the major antigen-presenting cells bridging innate and adaptive immunity, a function they perform by converting quiescent DC to active, mature DC with the capacity to activate naïve T cells. They do this by migrating from the tissues to the T cell area of the secondary lymphoid tissues. Here, we demonstrate that myeloid cell-specific genetic deletion of PTP1B (LysM PTP1B) leads to defects in lipopolysaccharide-driven bone marrow-derived DC (BMDC) activation associated with increased levels of phosphorylated Stat3. We show that myeloid cell-specific PTP1B deletion also causes decreased migratory capacity of epidermal DC, as well as reduced CCR7 expression and chemotaxis to CCL19 by BMDC. PTP1B deficiency in BMDC also impairs their migration in vivo. Further, immature LysM PTP1B BMDC display fewer podosomes, increased levels of phosphorylated Src at tyrosine 527, and loss of Src localization to podosome puncta. In co-culture with T cells, LysM PTP1B BMDC establish fewer and shorter contacts than control BMDC. Finally, LysM PTP1B BMDC fail to present antigen to T cells as efficiently as control BMDC. These data provide first evidence for a key regulatory role for PTP1B in mediating a central DC function of initiating adaptive immune responses in response to innate immune cell activation.

  16. Imbalanced Macrophage and Dendritic Cell Activations in Response to Candida albicans in a Murine Model of Diabetes Mellitus.

    Science.gov (United States)

    Venturini, James; Fraga-Silva, Thais Fernanda Campos; Marchetti, Camila Martins; Mimura, Luiza Ayumi Nishiyama; Conti, Bruno José; Golim, Márjorie de Assis; Mendes, Rinaldo Poncio; de Arruda, Maria Sueli Parreira

    2016-07-01

    Bloodstream infections caused by Candida species are responsible for high morbidity and mortality, and diabetes mellitus (DM) is an important underlying disease in candidemia episodes. Although DM patients show an enhanced proinflammatory profile, they are highly susceptible to mycobacterial and mycotic infections. Attempting to understand this paradox, we investigated if imbalanced macrophage and dendritic cell (DC) activations could be associated to high incidence and/or severity of Candida albicans infection in the hypoinsulinemia-hyperglycemia (HH) milieu. HH alloxan-induced mice were infected with C. albicans and peritoneal aderent phagocytes were co-cultured with or without lipopolyssaccharide or heat-killed C. albicans, and the production of cytotoxic metabolites, cytokines, and chemokines was evaluated. We also evaluated the surface expression of MHC-II and CD86 in splenic DCs. Our findings showed that both uninfected and C. albicans-infected HH mice showed less production of CCL2 and reduced expression of CD86 by peritoneal phagocytes and splenic DCs, respectively.

  17. Dendritic Cell

    OpenAIRE

    Sevda Söker

    2005-01-01

    Dendritic cells, a member of family of antigen presenting cells, are most effective cells in the primary immune response. Dendritic cells originated from dendron, in mean of tree in the Greek, because of their long and elaborate cytoplasmic branching processes. Dendritic cells constitute approximately 0.1 to 1 percent of the blood’s mononuclear cell. Dendritic cells are widely distributed, and specialized for antigen capture and T cell stimulation. In this article, structures and functions of...

  18. Models of neocortical layer 5b pyramidal cells capturing a wide range of dendritic and perisomatic active properties.

    Directory of Open Access Journals (Sweden)

    Etay Hay

    2011-07-01

    Full Text Available The thick-tufted layer 5b pyramidal cell extends its dendritic tree to all six layers of the mammalian neocortex and serves as a major building block for the cortical column. L5b pyramidal cells have been the subject of extensive experimental and modeling studies, yet conductance-based models of these cells that faithfully reproduce both their perisomatic Na(+-spiking behavior as well as key dendritic active properties, including Ca(2+ spikes and back-propagating action potentials, are still lacking. Based on a large body of experimental recordings from both the soma and dendrites of L5b pyramidal cells in adult rats, we characterized key features of the somatic and dendritic firing and quantified their statistics. We used these features to constrain the density of a set of ion channels over the soma and dendritic surface via multi-objective optimization with an evolutionary algorithm, thus generating a set of detailed conductance-based models that faithfully replicate the back-propagating action potential activated Ca(2+ spike firing and the perisomatic firing response to current steps, as well as the experimental variability of the properties. Furthermore, we show a useful way to analyze model parameters with our sets of models, which enabled us to identify some of the mechanisms responsible for the dynamic properties of L5b pyramidal cells as well as mechanisms that are sensitive to morphological changes. This automated framework can be used to develop a database of faithful models for other neuron types. The models we present provide several experimentally-testable predictions and can serve as a powerful tool for theoretical investigations of the contribution of single-cell dynamics to network activity and its computational capabilities.

  19. Inhibition of human dendritic cell activation by hydroethanolic but not lipophilic extracts of turmeric (Curcuma longa).

    Science.gov (United States)

    Krasovsky, Joseph; Chang, David H; Deng, Gary; Yeung, Simon; Lee, Mavis; Leung, Ping Chung; Cunningham-Rundles, Susanna; Cassileth, Barrie; Dhodapkar, Madhav V

    2009-03-01

    Turmeric has been extensively utilized in Indian and Chinese medicine for its immune-modulatory properties. Dendritic cells (DCs) are antigen-presenting cells specialized to initiate and regulate immunity. The ability of DCs to initiate immunity is linked to their activation status. The effects of turmeric on human DCs have not been studied. Here we show that hydroethanolic (HEE) but not lipophilic "supercritical" extraction (SCE) of turmeric inhibits the activation of human DCs in response to inflammatory cytokines. Treatment of DCs with HEE also inhibits the ability of DCs to stimulate the mixed lymphocyte reaction (MLR). Importantly, the lipophilic fraction does not synergize with the hydroethanolic fraction for the ability of inhibiting DC maturation. Rather, culturing of DCs with the combination of HEE and SCE leads to partial abrogation of the effects of HEE on the MLR initiated by DCs. These data provide a mechanism for the anti-inflammatory properties of turmeric. However, they suggest that these extracts are not synergistic and may contain components with mutually antagonistic effects on human DCs. Harnessing the immune effects of turmeric may benefit from specifically targeting the active fractions.

  20. Metabolic Control of Dendritic Cell Activation and Function: Recent Advances and Clinical Implications

    Directory of Open Access Journals (Sweden)

    Bart eEverts

    2014-05-01

    Full Text Available Dendritic cells (DCs are key regulators of both immunity and tolerance by controlling activation and polarization of effector T helper cell and regulatory T cell responses. Therefore, there is a major focus on developing approaches to manipulate DC function for immunotherapy. It is well known that changes in cellular activation are coupled to profound changes in cellular metabolism. Over the past decade there is a growing appreciation that these metabolic changes also underlie the capacity of immune cells to perform particular functions. This has led to the concept that the manipulation of cellular metabolism can be used to shape innate and adaptive immune responses. While most of our understanding in this area has been gained from studies with T cells and macrophages, evidence is emerging that the activation and function of DCs are also dictated by the type of metabolism these cells commit to. We here discuss these new insights and explore whether targeting of metabolic pathways in DCs could hold promise as a novel approach to manipulate the functional properties of DCs for clinical purposes.

  1. Expanding dendritic cells in vivo enhances the induction of oral tolerance.

    Science.gov (United States)

    Viney, J L; Mowat, A M; O'Malley, J M; Williamson, E; Fanger, N A

    1998-06-15

    The intestine is under perpetual challenge from both pathogens and essential nutrients, yet the mucosal immune system is able to discriminate effectively between harmful and innocuous Ags. It is likely that this selective immunoregulation is dependent on the nature of the APC at sites where gut Ags are processed and presented. Dendritic cells (DC) are considered the most potent of APC and are renowned for their immunostimulatory role in the initiation of immune responses. To investigate the role of DC in regulating the homeostatic balance between mucosal immunity and tolerance, we treated mice with Flt3 ligand (Flt3L), a growth factor that expands DC in vivo, and assessed subsequent systemic immune responsiveness using mouse models of oral tolerance. Surprisingly, mice treated with Flt3L to expand DC exhibited more profound systemic tolerance after they were fed soluble Ag. Most notably, tolerance could be induced in Flt3L-treated mice using very low doses of Ag that were ineffective in control animals. These findings contrast with the generally accepted view of DC as immunostimulatory APC and furthermore suggest a pivotal role for DC during the induction of tolerance following mucosal administration of Ag.

  2. Pleurotus ferulae water extract enhances the maturation and function of murine bone marrow-derived dendritic cells through TLR4 signaling pathway.

    Science.gov (United States)

    Li, Jinyao; Wang, Xinhui; Wang, Weilan; Luo, JiaoJiao; Aipire, Adila; Li, Jinyu; Zhang, Fuchun

    2015-04-15

    Dendritic cells (DCs) play important roles in the regulation of immune system, which link innate and adaptive immune responses. Mature DCs produced interleukin (IL)-12 promote optimal type 1 T helper (Th1) cells and cytotoxic T lymphocytes. The extracts of traditional herbal medicines have been shown to enhance immune responses through promoting the maturation and cytokine production of DCs. Here, we investigated the effects of Pleurotus ferulae water extract (PFWE) on the maturation and function of bone marrow-derived DCs (BM-DCs). Upon PFWE treatment, BM-DCs dose-dependently upregulated the expression of CD40, CD80, CD86 and MHC II and increased the production of IL-12, IL-6 and tumor necrosis factor (TNF)-α but not for IL-10, which is mediated by TLR4 signaling pathway, at least partially. The production of prostaglandin E2 (PGE2) in BM-DCs was decreased by the treatment of PFWE. Moreover, PFWE treatment decreased the expression of active caspase-3 but increased the expression of CCR7. PFWE treated DCs enhanced the proliferation of allogenic CD8(+) T cells and the capacity of antigen presenting to autologous CD8(+) T cells. The combination of PFWE and CpG-ODN further enhanced the maturation and function of murine BM-DCs. The results showed that PFWE could enhance the maturation and function of DCs through TLR4 signaling pathway and has additive effect when combined with CpG-ODN, suggesting that PFWE alone or combined with CpG-ODN could be used to enhance the immune responses.

  3. Signalling pathways involved in the activation of dendritic cells by layered double hydroxide nanoparticles.

    Science.gov (United States)

    Li, Ang; Qin, Lili; Zhu, Di; Zhu, Rongrong; Sun, Jing; Wang, Shilong

    2010-02-01

    Layered double hydroxide (LDH) nanoparticles are attractive as potential drug vectors for the targeting not only of tissues, but also of intracellular organelles, and particularly the acidic endolysosomes created after cell endocytosis. The purpose of this study was to investigate the ability of LDH nanoparticles designed as vectors to activate dendritic cells (DCs), as measured by various cellular functions. The study also explored the possible signaling pathway through which the LDH nanoparticles exerted their effects on the cellular functions of DCs. First, LDH nanoparticles with different ratios of Mg(OH)(2) to Al(OH)(3) (1:1, 2:1 and 3:1, called R1, R2 and R3 respectively) were optimized and had a hydrodynamic diameter of 57 nm with a zeta potential of +35 mV. Then, the efficient endocytosis of the optimized LDH nanoparticles by bone marrow-derived dendritic cells (MDDCs) was monitored by fluorescence-activated cell sorting. The effect of R1, R2 and R3 on the expression of the pro- and anti-inflammatory cytokines (TNF-alpha, IL-6, and IL-12) and the co-stimulatory molecules (CD40, CD80, CD86, and MHC class II) in MDDCs was examined. The exposure of R1 caused a dose-dependent increase in the expression of TNF-alpha, IL-12, CD86 and CD40, while R2 and R3 did not up-regulate these cytokines and co-stimulatory molecules. Migration assays showed that R1 could increase the migration capacity of DCs to CCL21 and up-regulate the expression of CCR7. Furthermore, we found that R1 significantly increased the NF-kappaB expression in the nucleus (in a dose-dependent manner) and promoted the degradation of total IkappaBalpha levels, indicating that the NF-kappaB signaling pathway might involve in an R1-induced DC activation. Our results suggested that LDH nanoparticles, in the future, may function as a useful vector for ex vivo engineering to promote vaccine delivery in immune cells.

  4. Dendritic nonlinearities reduce network size requirements and mediate ON and OFF states of persistent activity in a PFC microcircuit model.

    Directory of Open Access Journals (Sweden)

    Athanasia Papoutsi

    2014-07-01

    Full Text Available Technological advances have unraveled the existence of small clusters of co-active neurons in the neocortex. The functional implications of these microcircuits are in large part unexplored. Using a heavily constrained biophysical model of a L5 PFC microcircuit, we recently showed that these structures act as tunable modules of persistent activity, the cellular correlate of working memory. Here, we investigate the mechanisms that underlie persistent activity emergence (ON and termination (OFF and search for the minimum network size required for expressing these states within physiological regimes. We show that (a NMDA-mediated dendritic spikes gate the induction of persistent firing in the microcircuit. (b The minimum network size required for persistent activity induction is inversely proportional to the synaptic drive of each excitatory neuron. (c Relaxation of connectivity and synaptic delay constraints eliminates the gating effect of NMDA spikes, albeit at a cost of much larger networks. (d Persistent activity termination by increased inhibition depends on the strength of the synaptic input and is negatively modulated by dADP. (e Slow synaptic mechanisms and network activity contain predictive information regarding the ability of a given stimulus to turn ON and/or OFF persistent firing in the microcircuit model. Overall, this study zooms out from dendrites to cell assemblies and suggests a tight interaction between dendritic non-linearities and network properties (size/connectivity that may facilitate the short-memory function of the PFC.

  5. Fucoidan can function as an adjuvant in vivo to enhance dendritic cell maturation and function and promote antigen-specific T cell immune responses.

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    Jun-O Jin

    Full Text Available Fucoidan, a sulfated polysaccharide purified from brown algae, has a variety of immune-modulation effects, including promoting antigen uptake and enhancing anti-viral and anti-tumor effects. However, the effect of fucoidan in vivo, especially its adjuvant effect on in vivo anti-tumor immune responses, was not fully investigated. In this study, we investigated the effect of fucoidan on the function of spleen dendritic cells (DCs and its adjuvant effect in vivo. Systemic administration of fucoidan induced up-regulation of CD40, CD80 and CD86 expression and production of IL-6, IL-12 and TNF-α in spleen cDCs. Fucoidan also promoted the generation of IFN-γ-producing Th1 and Tc1 cells in an IL-12-dependent manner. When used as an adjuvant in vivo with ovalbumin (OVA antigen, fucoidan promoted OVA-specific antibody production and primed IFN-γ production in OVA-specific T cells. Moreover, fucoidan enhanced OVA-induced up-regulation of MHC class I and II on spleen cDCs and strongly prompted the proliferation of OVA-specific CD4 and CD8 T cells. Finally, OVA immunization with fucoidan as adjuvant protected mice from the challenge with B16-OVA tumor cells. Taken together, these results suggest that fucoidan can function as an adjuvant to induce Th1 immune response and CTL activation, which may be useful in tumor vaccine development.

  6. Enhanced antigen uptake by dendritic cells induced by the B pentamer of the type II heat-labile enterotoxin LT-IIa requires engagement of TLR2.

    Science.gov (United States)

    Lee, Chang Hoon; Nawar, Hesham F; Mandell, Lorrie; Liang, Shuang; Hajishengallis, George; Connell, Terry D

    2010-05-07

    The potent mucosal adjuvant properties of the type II heat-labile enterotoxin LT-IIa of Escherichia coli are dependent upon binding of the B pentamer of the enterotoxin (LT-IIa-B(5)) to ganglioside receptors on immunocompetent cells. To evaluate the immunomodulatory activities of LT-IIa-B(5), in vitro experiments employing bone marrow-derived dendritic cells (BMDC) were performed. Uptake of OVA-FITC, a model antigen (Ag), was enhanced by treatment of BMDC with LT-IIa-B5, but not by treatment of cells with the B pentamer of cholera toxin (CTB). Expression of co-stimulatory molecules (CD40, CD80, CD86, and MHC-II) and cytokines (IL-12p40, TNF-alpha, and IFN-gamma) was increased in BMDC treated with LT-IIa-B(5). The capacity of LT-IIa-B(5) to enhance Ag uptake and to induce expression of co-stimulatory receptors and cytokines by BMDC was dependent upon expression of TLR2 by the cell. Increased Ag uptake induced by LT-IIa-B(5) was correlated with increased Ag-specific proliferation of CD4(+) T cells in an in vitro syngeneic DO11.10 CD4(+) T cell proliferation assay. These experiments confirm that LT-IIa-B(5) exhibits potent immunomodulatory properties which may be exploitable as a non-toxic mucosal adjuvant.

  7. Danger signal-dependent activation of human dendritic cells by plasma-derived factor VIII products.

    Science.gov (United States)

    Miller, L; Weissmüller, S; Ringler, E; Crauwels, P; van Zandbergen, G; Seitz, R; Waibler, Z

    2015-08-01

    Treatment of haemophilia A by infusions of the clotting factor VIII (FVIII) results in the development of inhibitors/anti-drug antibodies in up to 25 % of patients. Mechanisms leading to immunogenicity of FVIII products are not yet fully understood. Amongst other factors, danger signals as elicited upon infection or surgery have been proposed to play a role. In the present study, we focused on effects of danger signals on maturation and activation of dendritic cells (DC) in the context of FVIII application. Human monocyte-derived DC were treated with FVIII alone, with a danger signal alone or a combination of both. By testing more than 60 different healthy donors, we show that FVIII and the bacterial danger signal lipopolysaccharide synergise in increasing DC activation, as characterised by increased expression of co-stimulatory molecules and secretion of pro-inflammatory cytokines. The degree and frequency of this synergistic activation correlate with CD86 expression levels on immature DC prior to stimulation. In our assay system, plasma-derived but not recombinant FVIII products activate human DC in a danger signal-dependent manner. Further tested danger signals, such as R848 also induced DC activation in combination with FVIII, albeit not in every tested donor. In our hands, human DC but not human B cells or macrophages could be activated by FVIII in a danger signal-dependent manner. Our results suggest that immunogenicity of FVIII is a result of multiple factors including the presence of danger, predisposition of the patient, and the choice of a FVIII product for treatment.

  8. The peptide sequence of diacyl lipopeptides determines dendritic cell TLR2-mediated NK activation.

    Science.gov (United States)

    Azuma, Masahiro; Sawahata, Ryoko; Akao, Yuusuke; Ebihara, Takashi; Yamazaki, Sayuri; Matsumoto, Misako; Hashimoto, Masahito; Fukase, Koichi; Fujimoto, Yukari; Seya, Tsukasa

    2010-09-02

    Natural killer (NK) cells are lymphocyte effectors that are activated to control certain microbial infections and tumors. Many NK-activating and regulating receptors are involved in regulating NK cell function. In addition, activation of naïve NK cells is fundamentally triggered by cytokines or myeloid dendritic cells (mDC) in various modes. In this study, we synthesized 16 S-[2,3-bis(palmitoyl)propyl]cysteine (Pam2Cys) lipopeptides with sequences designed from lipoproteins of Staphylococcus aureus, and assessed their functional properties using mouse (C57BL/6) bone marrow-derived DC (BMDC) and NK cells. NK cell activation was evaluated by three criteria: IFN-gamma production, up-regulation of NK activation markers and cytokines, and NK target (B16D8 cell) cytotoxicity. The diacylated lipopeptides acted as TLR2 ligands, inducing up-regulation of CD25/CD69/CD86, IL-6, and IL-12p40, which represent maturation of BMDC. Strikingly, the Pam2Cys lipopeptides induced mouse NK cell activation based on these criteria. Cell-cell contact by Pam2Cys peptide-stimulated BMDC and NK cells rather than soluble mediators released by stimulated BMDC induced activation of NK cells. For most lipopeptides, the BMDC TLR2/MyD88 pathway was responsible for driving NK activation, while some slightly induced direct activation of NK cells via the TLR2/MyD88 pathway in NK cells. The potential for NK activation was critically regulated by the peptide primary sequence. Hydrophobic or proline-containing sequences proximal to the N-terminal lipid moiety interfered with the ability of lipopeptides to induce BMDC-mediated NK activation. This mode of NK activation is distinctly different from that induced by polyI:C, which is closely associated with type I IFN-inducing pathways of BMDC. These results imply that the MyD88 pathway of BMDC governs an alternative NK-activating pathway in which the peptide sequence of TLR2-agonistic lipopeptides critically affects the potential for NK activation.

  9. The peptide sequence of diacyl lipopeptides determines dendritic cell TLR2-mediated NK activation.

    Directory of Open Access Journals (Sweden)

    Masahiro Azuma

    Full Text Available Natural killer (NK cells are lymphocyte effectors that are activated to control certain microbial infections and tumors. Many NK-activating and regulating receptors are involved in regulating NK cell function. In addition, activation of naïve NK cells is fundamentally triggered by cytokines or myeloid dendritic cells (mDC in various modes. In this study, we synthesized 16 S-[2,3-bis(palmitoylpropyl]cysteine (Pam2Cys lipopeptides with sequences designed from lipoproteins of Staphylococcus aureus, and assessed their functional properties using mouse (C57BL/6 bone marrow-derived DC (BMDC and NK cells. NK cell activation was evaluated by three criteria: IFN-gamma production, up-regulation of NK activation markers and cytokines, and NK target (B16D8 cell cytotoxicity. The diacylated lipopeptides acted as TLR2 ligands, inducing up-regulation of CD25/CD69/CD86, IL-6, and IL-12p40, which represent maturation of BMDC. Strikingly, the Pam2Cys lipopeptides induced mouse NK cell activation based on these criteria. Cell-cell contact by Pam2Cys peptide-stimulated BMDC and NK cells rather than soluble mediators released by stimulated BMDC induced activation of NK cells. For most lipopeptides, the BMDC TLR2/MyD88 pathway was responsible for driving NK activation, while some slightly induced direct activation of NK cells via the TLR2/MyD88 pathway in NK cells. The potential for NK activation was critically regulated by the peptide primary sequence. Hydrophobic or proline-containing sequences proximal to the N-terminal lipid moiety interfered with the ability of lipopeptides to induce BMDC-mediated NK activation. This mode of NK activation is distinctly different from that induced by polyI:C, which is closely associated with type I IFN-inducing pathways of BMDC. These results imply that the MyD88 pathway of BMDC governs an alternative NK-activating pathway in which the peptide sequence of TLR2-agonistic lipopeptides critically affects the potential for NK

  10. Rice Bran Feruloylated Oligosaccharides Activate Dendritic Cells via Toll-Like Receptor 2 and 4 Signaling

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    Chi Chen Lin

    2014-04-01

    Full Text Available This work presents the effects of feruloylated oligosaccharides (FOs of rice bran on murine bone marrow-derived dendritic cells (BMDCs and the potential pathway through which the effects are mediated. We found that FOs induced phenotypic maturation of DCs, as shown by the increased expression of CD40, CD80/CD86 and MHC-I/II molecules. FOs efficiently induced maturation of DCs generated from C3H/HeN or C57BL/6 mice with normal toll-like receptor 4 (TLR-4 or TLR-2 but not DCs from mice with mutated TLR4 or TLR2. The mechanism of action of FOs may be mediated by increased phosphorylation of ERK, p38 and JNK mitogen-activated protein kinase (MAPKs and increased NF-kB activity, which are important signaling molecules downstream of TLR-4 and TLR-2. These data suggest that FOs induce DCs maturation through TLR-4 and/or TLR-2 and that FOs might have potential efficacy against tumor or virus infection or represent a candidate-adjuvant approach for application in immunotherapy and vaccination.

  11. Rotavirus Infection Activates Dendritic Cells from Peyer's Patches in Adult Mice ▿ †

    Science.gov (United States)

    Lopez-Guerrero, Delia V.; Meza-Perez, Selene; Ramirez-Pliego, Oscar; Santana-Calderon, Maria A.; Espino-Solis, Pavel; Gutierrez-Xicotencatl, Lourdes; Flores-Romo, Leopoldo; Esquivel-Guadarrama, Fernando R.

    2010-01-01

    This study used an in vivo mouse model to analyze the response of dendritic cells (DCs) in Peyer's patches (PPs) within the first 48 h of infection with the wild-type murine rotavirus EDIM (EDIMwt). After the infection, the absolute number of DCs was increased by 2-fold in the PPs without a modification of their relative percentage of the total cell number. Also, the DCs from PPs of infected mice showed a time-dependent migration to the subepithelial dome (SED) and an increase of the surface activation markers CD40, CD80, and CD86. This response was more evident at 48 h postinfection (p.i.) and depended on viral replication, since DCs from PPs of mice inoculated with UV-treated virus did not show this phenotype. As a result of the activation, the DCs showed an increase in the expression of mRNA for the proinflammatory cytokines interleukin-12/23p40 (IL-12/23p40), tumor necrosis factor alpha (TNF-α), and beta interferon (IFN-β), as well as for the regulatory cytokine IL-10. These results suggest that, a short time after rotavirus infection, the DCs from PPs play a critical role in controlling the infection and, at the same time, avoiding an excessive inflammatory immune response. PMID:20007263

  12. Impact of MAPK pathway activation in BRAFV600 melanoma on T cell and Dendritic Cell function

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    Patrick Alexander Ott

    2013-10-01

    Full Text Available Constitutive upregulation of the MAPK pathway by a BRAFV600 mutation occurs in about half of melanomas. This leads to increased oncogenic properties such as tumor cell invasion, metastatic potential, and resistance to apoptosis. Blockade of the MAPK pathway with highly specific kinase inhibitors induces unprecedented tumor response rates in patients with advanced BRAFV600 mutant melanoma. Immune checkpoint blockade with monoclonal antibodies targeting CTLA-4 and PD-1/PD-L1 has also demonstrated striking anti-tumor activity in patients with advanced melanoma. Tumor responses are likely limited by multiple additional layers of immune suppression in the tumor microenvironment. There is emerging preclinical and clinical evidence suggesting that MAPK inhibition has a beneficial effect on the immunosuppressive tumor microenvironment, providing a strong rationale for combined immunotherapy and MAPK pathway inhibition in melanoma. The T cell response has been the main focus in the studies reported to date. Since dendritic cells (DCs are important in the induction of tumor-specific T cell responses, the impact of MAPK pathway activation in melanoma on DC function is critical for the melanoma directed immune response. BRAFV600E melanoma cells modulate DC through the MAPK pathway because its blockade in melanoma cells can reverse suppression of DC function. As both MEK/BRAF inhibition and immune checkpoint blockade have recently taken center stage in the treatment of melanoma, a deeper understanding of how MAPK pathway inhibition affects the tumor immune response is needed.

  13. Indoleamine 2, 3-dioxygenase (IDO) is essential for dendritic cell activation and chemotactic responsiveness to chemokines

    Institute of Scientific and Technical Information of China (English)

    Shih Ling HWANG; Nancy Pei-Yee CHUNG; Jacqueline Kwai-Yi CHAN; Chen-Lung Steve LIN

    2005-01-01

    Indoleamine 2, 3-dioxygenase (IDO) is a rate-limiting enzyme for the tryptophan catabolism. In human and murine cells, IDO inhibits antigen-specific T cell proliferation in vitro and suppresses T cell responses to fetal alloantigens during murine pregnancy. In mice, IDO expression is an inducible feature of specific subsets of dendritic cells (DCs),and is important for T cell regulatory properties. However, the effect of IDO and tryptophan deprivation on DC functions remains unknown. We report here that when tryptophan utilization was prevented by a pharmacological inhibitor of IDO, 1-methyl tryptophan (1MT), DC activation induced by pathogenic stimulus lipopolysaccharide (LPS) or inflammatory cytokine TNF-α was inhibited both phenotypically and functionally. Such an effect was less remarkable when DC was stimulated by a physiological stimulus, CD40 ligand. Tryptophan deprivation during DC activation also regulated the expression of CCR5 and CXCR4, as well as DC responsiveness to chemokines. These results suggest that tryptophan usage in the microenvironment is essential for DC maturation, and may also play a role in the regulation of DC migratory behaviors.

  14. Molecular programming of steady-state dendritic cells: impact on autoimmunity and tumor immune surveillance.

    Science.gov (United States)

    Johnson, Dylan J; Ohashi, Pamela S

    2013-05-01

    Dendritic cells are master regulators of immunity. Immature dendritic cells are essential for maintaining self-tolerance, while mature dendritic cells initiate a variety of specialized immune responses. Dendritic cell quiescence is often viewed as a default state that requires exogenous stimuli to induce maturation. However, recent studies have identified dendritic cell quiescence factors that actively program dendritic cells to an immature state. In the absence of these factors, dendritic cells spontaneously become immunogenic and can induce autoimmune responses. Herein we discuss two such factors, NF-κB1 and A20, that preserve dendritic cell immaturity through their regulation of NF-κB signaling. Loss of either of these factors increases dendritic cell immunogenicity, suggesting that they may be important targets for enhancing dendritic cell-based cancer immunotherapies. Alternatively, defects in molecules critical for maintaining steady-state DCs may provide novel biomarkers that identify patients who have enhanced natural antitumor immunity or that correlate with better responses to various immunotherapies.

  15. Interplay of dendritic non-linearities and network size mediate persistent activity in a PFC microcircuit model

    Directory of Open Access Journals (Sweden)

    Athanasia Papoutsi

    2014-03-01

    Full Text Available The ways in which neurons are embedded in a network to support various computations determines the functional output of the cortex. Recently, a number of in vivo studies have shown that dendritic integration in pyramidal neurons shapes neuronal function (Smith et al., 2013; Longordo et al., 2013 and that clusters of few reciprocally connected neurons are co-activated during behavioral tasks (Ko et al., 2011, 2013; Morishima et al., 2011. In the prefrontal cortex (PFC, such microcircuits are linked to persistent activity (prolonged spiking activity that exceeds stimulus presentation, which is the cellular correlate of working memory (Papoutsi et al., 2013. However, the effect of dendritic integration on the functional output of such small microcircuits has remained unexplored. In this work, we investigate the contribution of nonlinear dendritic properties to the induction and coding of upcoming state transitions in PFC microcircuits. Towards this goal we used a heavily constrained biophysical model of a layer 5 PFC microcircuit consisting of 7 pyramidal neurons and 2 interneurons implemented in the NEURON simulation environment. All neuron models are biophysically detailed but morphologically simplified and validated regarding their intrinsic, synaptic and connectivity properties (Papoutsi et al., 2013. Our results show that the non-linear integration of synaptic inputs at the basal dendrites of pyramidal neurons, mediated by the induction of NMDA spikes, is imperative for the emergence of the persistent state in the microcircuit: if synaptic drive is sufficient to induce NMDA spikes, the minimum network size required for persistent activity induction can be reduced down to 2 cells. In addition, slow synaptic mechanisms, such as the NMDA and GABAB currents, determine the ability of a given stimulus to induce persistent firing in the microcircuit model. On the other hand, the necessity for NMDA spikes disappears when persistent activity depends on

  16. P2X7R activation drives distinct IL-1 responses in dendritic cells compared to macrophages.

    Science.gov (United States)

    Englezou, Pavlos C; Rothwell, Simon W; Ainscough, Joseph S; Brough, David; Landsiedel, Robert; Verkhratsky, Alexei; Kimber, Ian; Dearman, Rebecca J

    2015-08-01

    The P2X(7)R is a functionally distinct member of the P2X family of non-selective cation channels associated with rapid activation of the inflammasome complex and signalling interleukin (IL)-1β release in macrophages. The main focus of this investigation was to compare P2X(7)R-driven IL-1 production by primary murine bone marrow derived dendritic cells (BMDC) and macrophages (BMM). P2X(7)R expression in murine BMDC and BMM at both transcriptional (P2X(7)A variant) and protein levels was demonstrated. Priming with lipopolysaccharide (LPS) and receptor activation with adenosine triphosphate (ATP) resulted in markedly enhanced IL-1 (α and β) secretion in BMDC compared with BMM. In both cell types IL-1 production was profoundly inhibited with a P2X(7)R-specific inhibitor (A-740003) demonstrating that this release is predominantly a P2X(7)R-dependent process. These data also suggest that P2X(7)R and caspase-1 activation drive IL-1α release from BMDC. Both cell types expressed constitutively the gain-of-function P2X(7)K as well as the full P2X(7)A variant at equivalent levels. LPS priming reduced significantly levels of P2X(7)A but not P2X(7)K transcripts in both BMDC and BMM. P2X(7)R-induced pore formation, assessed by YO-PRO-1 dye uptake, was greater in BMDC, and these cells were protected from cell death. These data demonstrate that DC and macrophages display distinct patterns of cytokine regulation, particularly with respect to IL-1, as a consequence of cell-type specific differences in the physicochemical properties of the P2X(7)R. Understanding the cell-specific regulation of these cytokines is essential for manipulating such responses in health and disease.

  17. Endocytosis following dopamine D2 receptor activation is critical for neuronal activity and dendritic spine formation via Rabex-5/PDGFRβ signaling in striatopallidal medium spiny neurons.

    Science.gov (United States)

    Shioda, N; Yabuki, Y; Wang, Y; Uchigashima, M; Hikida, T; Sasaoka, T; Mori, H; Watanabe, M; Sasahara, M; Fukunaga, K

    2016-12-06

    Aberrant dopamine D2 receptor (D2R) activity is associated with neuropsychiatric disorders, making those receptors targets for antipsychotic drugs. Here, we report that novel signaling through the intracellularly localized D2R long isoform (D2LR) elicits extracellular signal-regulated kinase (ERK) activation and dendritic spine formation through Rabex-5/platelet-derived growth factor receptor-β (PDGFRβ)-mediated endocytosis in mouse striatum. We found that D2LR directly binds to and activates Rabex-5, promoting early-endosome formation. Endosomes containing D2LR and PDGFRβ are then transported to the Golgi apparatus, where those complexes trigger Gαi3-mediated ERK signaling. Loss of intracellular D2LR-mediated ERK activation decreased neuronal activity and dendritic spine density in striatopallidal medium spiny neurons (MSNs). In addition, dendritic spine density in striatopallidal MSNs significantly increased following treatment of striatal slices from wild-type mice with quinpirole, a D2R agonist, but those changes were lacking in D2LR knockout mice. Moreover, intracellular D2LR signaling mediated effects of a typical antipsychotic drug, haloperidol, in inducing catalepsy behavior. Taken together, intracellular D2LR signaling through Rabex-5/PDGFRβ is critical for ERK activation, dendritic spine formation and neuronal activity in striatopallidal MSNs of mice.Molecular Psychiatry advance online publication, 6 December 2016; doi:10.1038/mp.2016.200.

  18. A Model of Cytotoxic T Antitumor Activation Stimulated by Pulsed Dendritic Cells

    Science.gov (United States)

    Pennisi, Marzio; Pappalardo, Francesco; Chiacchio, Ferdinando; Motta, Santo

    2011-09-01

    We present a preliminary ODE model to sketch the immune response of cytotoxic T cells against cancer through the use of pulsed autologous dendritic cells. The model is partially based on data coming from experiments that are presently in progress in the wet lab of our collaborators, but it can be applied in principle to different tumors. To this end, we show the immune response of cytotoxic T cells stimulated by autologous dendritic cells for different cancers.

  19. Complementary Dendritic Cell–activating Function of CD8+ and CD4+ T Cells

    Science.gov (United States)

    Mailliard, Robbie B.; Egawa, Shinichi; Cai, Quan; Kalinska, Anna; Bykovskaya, Svetlana N.; Lotze, Michael T.; Kapsenberg, Martien L.; Storkus, Walter J.; Kalinski, Pawel

    2002-01-01

    Dendritic cells (DCs) activated by CD40L-expressing CD4+ T cells act as mediators of “T helper (Th)” signals for CD8+ T lymphocytes, inducing their cytotoxic function and supporting their long-term activity. Here, we show that the optimal activation of DCs, their ability to produce high levels of bioactive interleukin (IL)-12p70 and to induce Th1-type CD4+ T cells, is supported by the complementary DC-activating signals from both CD4+ and CD8+ T cells. Cord blood– or peripheral blood–isolated naive CD8+ T cells do not express CD40L, but, in contrast to naive CD4+ T cells, they are efficient producers of IFN-γ at the earliest stages of the interaction with DCs. Naive CD8+ T cells cooperate with CD40L-expressing naive CD4+ T cells in the induction of IL-12p70 in DCs, promoting the development of primary Th1-type CD4+ T cell responses. Moreover, the recognition of major histocompatibility complex class I–presented epitopes by antigen-specific CD8+ T cells results in the TNF-α– and IFN-γ–dependent increase in the activation level of DCs and in the induction of type-1 polarized mature DCs capable of producing high levels of IL-12p70 upon a subsequent CD40 ligation. The ability of class I–restricted CD8+ T cells to coactivate and polarize DCs may support the induction of Th1-type responses against class I–presented epitopes of intracellular pathogens and contact allergens, and may have therapeutical implications in cancer and chronic infections. PMID:11854360

  20. Analysis of the interaction between the dendritic conductance density and activated area in modulating alpha-motoneuron EPSP: statistical computer model.

    Science.gov (United States)

    Gradwohl, Gideon; Grossman, Yoram

    2008-06-01

    Five reconstructed alpha-motoneurons (MNs) are simulated under physiological and morphological realistic parameters. We compare the resulting excitatory postsynaptic potential (EPSP) of models, containing voltage-dependent channels on the dendrites, with the EPSP of a passive MN and an active soma and axon model. In our simulations, we apply three different distribution functions of the voltage-dependent channels on the dendrites: a step function (ST) with uniform spatial dispersion; an exponential decay (ED) function, with proximal to the soma high-density location; and an exponential rise (ER) with distally located conductance density. In all cases, the synaptic inputs are located as a gaussian function on the dendrites. Our simulations lead to eight key observations. (1) The presence of the voltage-dependent channels conductance (g(Active)) in the dendrites is vital for obtaining EPSP peak boosting. (2) The mean EPSP peaks of the ST, ER, and ED distributions are similar when the ranges of G (total conductance) are equal. (3) EPSP peak increases monotonically when the magnitude of g(Na_step) (maximal g(Na) at a particular run) is increased. (4) EPSP kinetics parameters were differentially affected; time integral was decreased monotonically with increased g(Na_step), but the rate of rise (the decay time was not analyzed) does not show clear relations. (5) The total G can be elevated by increasing the number of active dendrites; however, only a small active area of the dendritic tree is sufficient to get the maximal boosting. (6) The sometimes large variations in the parameters values for identical G depend on the g(Na_step) and active dendritic area. (7) High g(Na_step) in a few dendrites is more efficient in amplifying the EPSP peak than low g(Na_step) in many dendrites. (8) The EPSP peak is approximately linear with respect to the MNs' R(N) (input resistance).

  1. Modification to the capsid of the adenovirus vector that enhances dendritic cell infection and transgene-specific cellular immune responses.

    Science.gov (United States)

    Worgall, Stefan; Busch, Annette; Rivara, Michael; Bonnyay, David; Leopold, Philip L; Merritt, Robert; Hackett, Neil R; Rovelink, Peter W; Bruder, Joseph T; Wickham, Thomas J; Kovesdi, Imi; Crystal, Ronald G

    2004-03-01

    Adenovirus (Ad) gene transfer vectors can be used to transfer and express antigens and function as strong adjuvants and thus are useful platforms for the development of genetic vaccines. Based on the hypothesis that Ad vectors with enhanced infectibility of dendritic cells (DC) may be able to evoke enhanced immune responses against antigens encoded by the vector in vivo, the present study analyzes the vaccine potential of an Ad vector expressing beta-galactosidase as a model antigen and genetically modified with RGD on the fiber knob [AdZ.F(RGD)] to more selectively infect DC and consequently enhance immunity against the beta-galactosidase antigen. Infection of murine DC in vitro with AdZ.F(RGD) showed an eightfold-increased transgene expression following infection compared to AdZ (also expressing beta-galactosidase, but with a wild-type capsid). Binding, cellular uptake, and trafficking in DC were also increased with AdZ.F(RGD) compared to AdZ. To determine whether AdZ.F(RGD) could evoke enhanced immune responses to beta-galactosidase in vivo, C57BL/6 mice were immunized with AdZ.F(RGD) or AdZ subcutaneously via the footpad. Humoral responses with both vectors were comparable, with similar anti-beta-galactosidase antibody levels following vector administration. However, cellular responses to beta-galactosidase were significantly enhanced, with the frequency of CD4(+) as well as the CD8(+) beta-galactosidase-specific gamma interferon response in cells isolated from the draining lymph nodes increased following immunization with AdZ.F(RGD) compared to Ad.Z (P AdZ.F(RGD) vector was sufficient to evoke enhanced inhibition of the growth of preexisting tumors expressing beta-galactosidase: BALB/c mice implanted with the CT26 syngeneic beta-galactosidase-expressing colon carcinoma cell line and subsequently immunized with AdZ.F(RGD) showed decreased tumor growth and improved survival compared to mice immunized with AdZ. These data demonstrate that addition of an RGD motif

  2. Dendrite Injury Triggers DLK-Independent Regeneration

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    Michelle C. Stone

    2014-01-01

    Full Text Available Axon injury triggers regeneration through activation of a conserved kinase cascade, which includes the dual leucine zipper kinase (DLK. Although dendrites are damaged during stroke, traumatic brain injury, and seizure, it is not known whether mature neurons monitor dendrite injury and initiate regeneration. We probed the response to dendrite damage using model Drosophila neurons. Two larval neuron types regrew dendrites in distinct ways after all dendrites were removed. Dendrite regeneration was also triggered by injury in adults. Next, we tested whether dendrite injury was initiated with the same machinery as axon injury. Surprisingly, DLK, JNK, and fos were dispensable for dendrite regeneration. Moreover, this MAP kinase pathway was not activated by injury to dendrites. Thus, neurons respond to dendrite damage and initiate regeneration without using the conserved DLK cascade that triggers axon regeneration.

  3. Slow recovery from inactivation of Na+ channels underlies the activity-dependent attenuation of dendritic action potentials in hippocampal CA1 pyramidal neurons.

    Science.gov (United States)

    Colbert, C M; Magee, J C; Hoffman, D A; Johnston, D

    1997-09-01

    Na+ action potentials propagate into the dendrites of pyramidal neurons driving an influx of Ca2+ that seems to be important for associative synaptic plasticity. During repetitive (10-50 Hz) firing, dendritic action potentials display a marked and prolonged voltage-dependent decrease in amplitude. Such a decrease is not apparent in somatic action potentials. We investigated the mechanisms of the different activity dependence of somatic and dendritic action potentials in CA1 pyramidal neurons of adult rats using whole-cell and cell-attached patch-clamp methods. There were three main findings. First, dendritic Na+ currents decreased in amplitude when repeatedly activated by brief (2 msec) depolarizations. Recovery was slow and voltage-dependent. Second, Na+ currents decreased much less in somatic than in dendritic patches. Third, although K+ currents remained constant during trains, K+ currents were necessary for dendritic action potential amplitude to decrease in whole-cell experiments. These results suggest that regional differences in Na+ and K+ channels determine the differences in the activity dependence of somatic and dendritic action potential amplitudes.

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

    Science.gov (United States)

    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.

  5. Human Liver Stem Cells Suppress T-Cell Proliferation, NK Activity, and Dendritic Cell Differentiation

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    Stefania Bruno

    2016-01-01

    Full Text Available Human liver stem cells (HLSCs are a mesenchymal stromal cell-like population resident in the adult liver. Preclinical studies indicate that HLSCs could be a good candidate for cell therapy. The aim of the present study was to evaluate the immunogenicity and the immunomodulatory properties of HLSCs on T-lymphocytes, natural killer cells (NKs, and dendritic cells (DCs in allogeneic experimental settings. We found that HLSCs inhibited T-cell proliferation by a mechanism independent of cell contact and dependent on the release of prostaglandin E2 (PGE2 and on indoleamine 2,3-dioxygenase activity. When compared with mesenchymal stromal cells (MSCs, HLSCs were more efficient in inhibiting T-cell proliferation. At variance with MSCs, HLSCs did not elicit NK degranulation. Moreover, HLSCs inhibited NK degranulation against K562, a NK-sensitive target, by a mechanism dependent on HLA-G release. When tested on DC generation from monocytes, HLSCs were found to impair DC differentiation and DCs ability to induce T-cell proliferation through PGE2. This study shows that HLSCs have immunomodulatory properties similar to MSCs, but, at variance with MSCs, they do not elicit a NK response.

  6. Human Liver Stem Cells Suppress T-Cell Proliferation, NK Activity, and Dendritic Cell Differentiation.

    Science.gov (United States)

    Bruno, Stefania; Grange, Cristina; Tapparo, Marta; Pasquino, Chiara; Romagnoli, Renato; Dametto, Ennia; Amoroso, Antonio; Tetta, Ciro; Camussi, Giovanni

    2016-01-01

    Human liver stem cells (HLSCs) are a mesenchymal stromal cell-like population resident in the adult liver. Preclinical studies indicate that HLSCs could be a good candidate for cell therapy. The aim of the present study was to evaluate the immunogenicity and the immunomodulatory properties of HLSCs on T-lymphocytes, natural killer cells (NKs), and dendritic cells (DCs) in allogeneic experimental settings. We found that HLSCs inhibited T-cell proliferation by a mechanism independent of cell contact and dependent on the release of prostaglandin E2 (PGE2) and on indoleamine 2,3-dioxygenase activity. When compared with mesenchymal stromal cells (MSCs), HLSCs were more efficient in inhibiting T-cell proliferation. At variance with MSCs, HLSCs did not elicit NK degranulation. Moreover, HLSCs inhibited NK degranulation against K562, a NK-sensitive target, by a mechanism dependent on HLA-G release. When tested on DC generation from monocytes, HLSCs were found to impair DC differentiation and DCs ability to induce T-cell proliferation through PGE2. This study shows that HLSCs have immunomodulatory properties similar to MSCs, but, at variance with MSCs, they do not elicit a NK response.

  7. Brugia malayi infective larvae fail to activate Langerhans cells and dermal dendritic cells in human skin.

    Science.gov (United States)

    Cotton, R N; McDonald-Fleming, R; Boyd, A; Spates, K; Nutman, T B; Tolouei Semnani, R

    2015-02-01

    Filarial infection in humans is initiated when a mosquito deposits third-stage parasite larvae (L3) in the skin. Langerhans cells (LCs) and dermal dendritic cells (DDCs) are the first cells that the parasite encounters, and L3s must evade these highly effective antigen-presenting cells to establish infection. To assess LC and DDC responses to L3 in human skin, we employed three models of increasing physiologic relevance: in vitro-generated LCs, epidermal blister explants and full-thickness human skin sections. In vitro-generated LCs expressed TLR1-10 and robustly produced IL-6 and TNF-α in response to PolyI:C, but pre-exposure to L3s did not alter inflammatory cytokine production or TLR expression. L3s did not modulate expression of LC markers CDH1, CD207, or CD1a, or the regulatory products TSLP or IDO in epidermal explants or in vitro-generated LC. LC, CD14+ DDC, CD1c+ DC and CD141+ DC from human skin sections were analysed by flow cytometry. While PolyI:C potently induced CCL22 production in LC, CD1c+ DC, and CD141+ DC, and IL-10 production in LC, L3s did not modulate the numbers of or cytokine production by any skin DC subset. L3s broadly failed to activate or modulate LCs or DDCs, suggesting filarial larvae expertly evade APC detection in human skin.

  8. Fluorescent activated cell sorting: an effective approach to study dendritic cell subsets in human atherosclerotic plaques.

    Science.gov (United States)

    Van Brussel, Ilse; Ammi, Rachid; Rombouts, Miche; Cools, Nathalie; Vercauteren, Sven R; De Roover, Dominique; Hendriks, Jeroen M H; Lauwers, Patrick; Van Schil, Paul E; Schrijvers, Dorien M

    2015-02-01

    Different immune cell types are present within atherosclerotic plaques. Dendritic cells (DC) are of special interest, since they are considered as the 'center of the immuniverse'. Identifying inflammatory DC subtypes within plaques is important for a better understanding of the lesion pathogenesis and pinpoints their contribution to the atherosclerotic process. We have developed a flow cytometry-based method to characterize and isolate different DC subsets (i.e. CD11b(+), Clec9A(+) and CD16(+) conventional (c)DC and CD123(+) plasmacytoid (p)DC) in human atherosclerotic plaques. We revealed a predominance of pro-inflammatory CD11b(+) DC in advanced human lesions, whereas atheroprotective Clec9A(+) DC were almost absent. CD123(+) pDC and CD16(+) DC were also detectable in plaques. Remarkably, plaques from distinct anatomical locations exhibited different cellular compositions: femoral plaques contained less CD11b(+) and Clec9A(+) DC than carotid plaques. Twice as many monocytes/macrophages were observed compared to DC. Moreover, relative amounts of T cells/B cells/NK cells were 6 times as high as DC numbers. For the first time, fluorescent activated cell sorting analysis of DC subsets in human plaques indicated a predominance of CD11b(+) cDC, in comparison with other DC subsets. Isolation of the different subsets will facilitate detailed functional analysis and may have significant implications for tailoring appropriate therapy.

  9. Infected dendritic cells are sufficient to mediate the adjuvant activity generated by Venezuelan equine encephalitis virus replicon particles

    OpenAIRE

    Tonkin, Daniel R.; Whitmore, Alan; Robert E Johnston; Barro, Mario

    2012-01-01

    Replicon particles derived from Venezuelan equine encephalitis virus (VEE) are infectious non-propagating particles which act as a safe and potent systemic, mucosal, and cellular adjuvant when delivered with antigen. VEE and VEE replicon particles (VRP) can target multiple cell types including dendritic cells (DCs). The role of these cell types in VRP adjuvant activity has not been previously evaluated, and for these studies we focused on the contribution of DCs to the response to VRP. By ana...

  10. Comparative analysis of signature genes in porcine reproductive and respiratory syndrome virus (PRRSV)-infected porcine monocyte-derived dendritic cells at differential activation statuses

    Science.gov (United States)

    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...

  11. A novel dendritic surfactant for enhanced microcystin-LR detection by double amplification in a quartz crystal microbalance biosensor.

    Science.gov (United States)

    Xia, Yuetong; Zhang, Jianping; Jiang, Long

    2011-08-01

    Enhanced sensitivity for the hepatotoxin microcystin-LR (MC-LR) was achieved in a quartz crystal microbalance (QCM) system via double amplification. For primary amplification, an innovative interface on the QCM was obtained as a matrix by the vesicle layer formed by our synthetic dendritic surfactant, bis (amidoethyl-carbamoylethyl) octadecylamine (C18N3). The vesicle matrix was then functionalised by an optimised concentration of monoclonal antibodies against MC-LR (anti-MC-LR) to detect the analyte. The results showed that a detection limit of 100 ng/mL was achieved by primary amplification. To achieve higher sensitivity, secondary amplification was implemented with anti-MC-LR gold nanoparticle (AuNPs) conjugates as probes, which lowered the detection limit for MC-LR to 1 ng/mL (the maximum concentration recommended by the World Health Organization [WHO] in drinking water for humans). The QCM immunosensor reported here has advantages such as high sensitivity, portability, simplicity, and cost-effectiveness for MC-LR detection. It would be uniquely superior compared with current MC-LR detection techniques for on-the-spot water detection. Furthermore, the methodology described here is also potentially significant in many fields for the routine monitoring of environmental and food safety.

  12. Sequential activation of p75 and TrkB is involved in dendritic development of subventricular zone-derived neuronal progenitors in vitro.

    Science.gov (United States)

    Gascon, E; Vutskits, L; Zhang, H; Barral-Moran, M J; Kiss, P J; Mas, C; Kiss, J Z

    2005-01-01

    Dendritic arbor development of subventricular zone-derived interneurons is a critical step in their integration into functional circuits of the postnatal olfactory bulb. However, the mechanism and molecular control of this process remain unknown. In this study, we have developed a culture model where dendritic development of purified subventricular zone cells proceeds under serum-free conditions in the absence of added growth factors and non-neural cells. We demonstrate that the large majority of these cells in culture express GABA and elaborate dendritic arbors with spine-like protrusions but they do not possess axons. These neurons expressed receptors for neurotrophins including p75, TrkB and TrkC but not TrkA. Application of exogenous neurotrophins, including brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT3) and nerve growth factor (NGF), to cultures stimulated dendritic growth and led to more complex dendritic arbors during the initial 3 days in culture. Our results suggest that these effects are independent of Trk receptors and mediated by the p75/ceramide signaling pathway. We also show that brain-derived neurotrophic factor is the only neurotrophin that is able to influence late-phase dendritic development via TrkB receptor activation. These results suggest that dendritic arbor development of subventricular zone-derived cells may be regulated by neurotrophins through the activation of p75 and the TrkB receptor signaling pathways in a sequentially defined temporal pattern.

  13. Diffusion and extrusion shape standing calcium gradients during ongoing parallel fiber activity in dendrites of Purkinje neurons.

    Science.gov (United States)

    Schmidt, Hartmut; Arendt, Oliver; Eilers, Jens

    2012-09-01

    Synaptically induced calcium transients in dendrites of Purkinje neurons (PNs) play a key role in the induction of plasticity in the cerebellar cortex (Ito, Physiol Rev 81:1143-1195, 2001). Long-term depression at parallel fiber-PN synapses can be induced by stimulation paradigms that are associated with long-lasting (>1 min) calcium signals. These signals remain strictly localized (Eilers et al., Learn Mem 3:159-168, 1997), an observation that was rather unexpected, given the high concentration of the mobile endogenous calcium-binding proteins parvalbumin and calbindin in PNs (Fierro and Llano, J Physiol (Lond) 496:617-625, 1996; Kosaka et al., Exp Brain Res 93:483-491, 1993). By combining two-photon calcium imaging experiments in acute slices with numerical computer simulations, we found that significant calcium diffusion out of active branches indeed takes places. It is outweighed, however, by rapid and powerful calcium extrusion along the dendritic shaft. The close interplay of diffusion and extrusion defines the spread of calcium between active and inactive dendritic branches, forming a steep gradient in calcium with drop ranges of ~13 μm (interquartile range, 10-18 μm).

  14. Platelet-Activating Factor Antagonists Decrease Follicular Dendritic-Cell Stimulation of Human B Lymphocytes

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    Halickman Isaac

    2005-06-01

    Full Text Available Abstract Both B-lymphoblastoid cell lines and tonsillar B lymphocytes express receptors for platelet-activating factor (PAF. In lymph node germinal centres, B lymphocytes interact with follicular dendritic cells (FDCs, which present antigen-containing immune complexes to B lymphocytes. FDCs have phenotypic features that are similar to those of stromal cells and monocytes and may therefore be a source of lipid mediators. In this study, we evaluated the effects of the PAF antagonist WEB 2170 on the activation of tonsillar B lymphocytes by FDCs. FDCs were isolated from tonsils by Bovine Serum Albumin (BSA gradient centrifugation. After being cultured for 6 to 10 days, they were incubated with freshly isolated B cells in the presence or absence of the specific PAF receptor antagonist WEB 2170. B-lymphocyte proliferation was assessed by [3H]-thymidine incorporation, and immunoglobulin (Ig G and IgM secretion was assessed by enzyme-linked immunosorbent assay (ELISA. WEB 2170 (10-6 to 10-8 M inhibited [3H]-thymidine incorporation by up to 35% ± 3%. Moreover, the secretion of IgG and IgM was inhibited by up to 50% by WEB 2170 concentrations ranging from 10-6 to 10-8 M. There was no evidence of toxicity by trypan blue staining, and the addition of WEB 2170 to B cells in the absence of FDCs did not inhibit the spontaneous production of IgG or IgM. The effect of the PAF antagonist is primarily on B lymphocytes, as reverse transcription polymerase chain reaction detected little PAF receptor messenger ribonucleic acid (mRNA from FDCs. These data suggest that endogenous production of PAF may be important in the interaction of B lymphocytes with FDCs.

  15. Impaired NK Cell Activation and Chemotaxis toward Dendritic Cells Exposed to Complement-Opsonized HIV-1

    Science.gov (United States)

    Ellegård, Rada; Crisci, Elisa; Andersson, Jonas; Shankar, Esaki M.; Nyström, Sofia; Hinkula, Jorma

    2015-01-01

    Mucosa resident dendritic cells (DCs) may represent one of the first immune cells that HIV-1 encounters during sexual transmission. The virions in body fluids can be opsonized with complement factors because of HIV-mediated triggering of the complement cascade, and this appears to influence numerous aspects of the immune defense targeting the virus. One key attribute of host defense is the ability to attract immune cells to the site of infection. In this study, we investigated whether the opsonization of HIV with complement (C-HIV) or a mixture of complement and Abs (CI-HIV) affected the cytokine and chemokine responses generated by DCs, as well as their ability to attract other immune cells. We found that the expression levels of CXCL8, CXCL10, CCL3, and CCL17 were lowered after exposure to either C-HIV or CI-HIV relative to free HIV (F-HIV). DCs exposed to F-HIV induced higher cell migration, consisting mainly of NK cells, compared with opsonized virus, and the chemotaxis of NK cells was dependent on CCL3 and CXCL10. NK cell exposure to supernatants derived from HIV-exposed DCs showed that F-HIV induced phenotypic activation (e.g., increased levels of TIM3, CD69, and CD25) and effector function (e.g., production of IFNγ and killing of target cells) in NK cells, whereas C-HIV and CI-HIV did not. The impairment of NK cell recruitment by DCs exposed to complement-opsonized HIV and the lack of NK activation may contribute to the failure of innate immune responses to control HIV at the site of initial mucosa infection. PMID:26157174

  16. Salvianolic acid B suppresses maturation of human monocyte-derived dendritic cells by activating PPARγ

    Science.gov (United States)

    Sun, Aijun; Liu, Hongying; Wang, Shijun; Shi, Dazhuo; Xu, Lei; Cheng, Yong; Wang, Keqiang; Chen, Keji; Zou, Yunzeng; Ge, Junbo

    2011-01-01

    BACKGROUND AND PURPOSE Salvianolic acid B (Sal B), a water-soluble antioxidant derived from a Chinese medicinal herb, is known to be effective in the prevention of atherosclerosis. Here, we tested the hypothesis that the anti-atherosclerotic effect of Sal B might be mediated by suppressing maturation of human monocyte-derived dendritic cells (h-monDC). EXPERIMENTAL APPROACH h-monDC were derived by incubating purified human monocytes with GM-CSF and IL-4. h-monDC were pre-incubated with or without Sal B and stimulated by oxidized low-density lipoprotein (ox-LDL) in the presence or absence of PPARγ siRNA. Expression of h-monDC membrane molecules (CD40, CD86, CD1a, HLA-DR) were analysed by FACS, cytokines were measured by elisa and the TLR4-associated signalling pathway was determined by Western blotting. KEY RESULTS Ox-LDL promoted h-monDC maturation, stimulated CD40, CD86, CD1a, HLA-DR expression and IL-12, IL-10, TNF-α production; and up-regulated TLR4 signalling. These effects were inhibited by Sal B. Sal B also triggered PPARγ activation and promoted PPARγ nuclear translocation, attenuated ox-LDL-induced up-regulation of TLR4 and myeloid differentiation primary-response protein 88 and inhibited the downstream p38-MAPK signalling cascade. Knocking down PPARγ with the corresponding siRNA blocked these effects of Sal B. CONCLUSIONS AND IMPLICATIONS Our data suggested that Sal B effectively suppressed maturation of h-monDC induced by ox-LDL through PPARγ activation. PMID:21649636

  17. Piperine impairs the migration and T cell-activating function of dendritic cells.

    Science.gov (United States)

    Rodgers, Gemma; Doucette, Carolyn D; Soutar, David A; Liwski, Robert S; Hoskin, David W

    2016-02-03

    Piperine, a major alkaloid found in the fruits of black and long pepper plants, has anti-inflammatory properties; however, piperine's effect on dendritic cell (DC) migration and T cell-activating function has not been investigated. Bone marrow-derived mouse DCs that were matured in the presence of 100 μM piperine showed reduced in vitro migration in response to CCL21, as well as reduced in vivo migration to lymph nodes. In addition, piperine-treated DCs had reduced CCR7 expression and elevated CCR5 expression, as well as reduced expression of CD40 and class II major histocompatibility complex molecules and decreased nuclear accumulation of RelB. DC production of interleukin (IL)-6, tumor necrosis factor α, and monocyte chemoattractant protein-1 in response to lipopolysaccharide stimulation was also reduced following piperine treatment. Exposure to piperine during maturation therefore caused DCs to retain an immature phenotype, which was associated with a reduced capacity to promote T cell activation since co-culture of ovalbumin (OVA323-339)-specific T cells with OVA323-339-pulsed DCs that were previously matured in the presence of piperine showed reduced interferon-γ and IL-2 expression. OVA323-339-specific T cell proliferation was also reduced in vivo in the presence of piperine-treated DCs. Inhibition of DC migration and function by piperine may therefore be a useful strategy to down-regulate potentially harmful DC-driven T cell responses to self-antigens and transplantation antigens.

  18. KIS, a kinase associated with microtubule regulators, enhances translation of AMPA receptors and stimulates dendritic spine remodeling.

    Science.gov (United States)

    Pedraza, Neus; Ortiz, Raúl; Cornadó, Alba; Llobet, Artur; Aldea, Martí; Gallego, Carme

    2014-10-15

    Local regulation of protein synthesis allows a neuron to rapidly alter the proteome in response to synaptic signals, an essential mechanism in synaptic plasticity that is altered in many neurological diseases. Synthesis of many synaptic proteins is under local control and much of this regulation occurs through structures termed RNA granules. KIS is a protein kinase that associates with stathmin, a modulator of the tubulin cytoskeleton. Furthermore, KIS is found in RNA granules and stimulates translation driven by the β-actin 3'UTR in neurites. Here we explore the physiological and molecular mechanisms underlying the action of KIS on hippocampal synaptic plasticity in mice. KIS downregulation compromises spine development, alters actin dynamics, and reduces postsynaptic responsiveness. The absence of KIS results in a significant decrease of protein levels of PSD-95, a postsynaptic scaffolding protein, and the AMPAR subunits GluR1 and GluR2 in a CPEB3-dependent manner. Underlying its role in spine maturation, KIS is able to suppress the spine developmental defects caused by CPEB3 overexpression. Moreover, either by direct or indirect mechanisms, KIS counteracts the inhibitory activity of CPEB3 on the GluR2 3'UTR at both mRNA translation and polyadenylation levels. Our study provides insights into the mechanisms that mediate dendritic spine morphogenesis and functional synaptic maturation, and suggests KIS as a link regulating spine cytoskeleton and postsynaptic activity in memory formation.

  19. Influence of autologous dendritic cells on cytokine-induced killer cell proliferation, cell phenotype and antitumor activity in vitro.

    Science.gov (United States)

    Cao, Jingsong; Chen, Cong; Wang, Yuhuan; Chen, Xuecheng; Chen, Zeying; Luo, Xiaoling

    2016-09-01

    Dendritic cell (DCs) are essential antigen processing and presentation cells that play a key role in the immune response. In this study, DCs were co-cultured with cytokine-induced killer cells (DC-CIKs) in vitro to detect changes in cell proliferation, cell phenotype and cell cytotoxicity. The results revealed that the DCs were suitable for co-culture with CIKs at day 7, and that cell quantity of DC-CIKs was lower than that of CIKs until day 11, but it was significantly improved to 1.17-fold that of CIKs at day 13. Flow cytometry was used to detect the cell phenotype of CIKs and DC-CIKs. Compared with CIKs at day 13, the percentage of CD3(+), CD3(+)CD4(+), CD3(+)CD8(+) and CD3(+)CD56(+) T cells in DC-CIKs was significantly improved 1.02, 1.79, 1.26 and 2.44-fold, respectively. In addition, trypan blue staining analysis demonstrated that the cell viability of CIKs and DC-CIKs was 96% and 98%, respectively. Furthermore, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) analysis verified that CIK and DC-CIK cytotoxicity in Hela cells was 58% and 80%, respectively, with a significant difference. Taken together, our results indicate that the cell proliferation, cell phenotype and antitumor activity of CIKs were all enhanced following co-culture with DCs in vitro. These results are likely to be useful for DC-CIK application in antitumor therapies.

  20. Activation and Genetic Modification of Human Monocyte-Derived Dendritic Cells using Attenuated Salmonella typhimurium

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    Agnieszka Michael

    2010-01-01

    Full Text Available Live attenuated bacterial vectors, such as Salmonella typhimurium, have shown promise as delivery vehicles for DNA. We have examined two new strains of S. typhimurium and their impact on dendritic cell maturation (CD12-sifA/aroC mutant and WT05-ssaV/aroC, both in TML background. Strain WT05 matured dendritic cells in a more efficient way; caused higher release of cytokines TNF-α, IL-12, IL-1β; and was efficient for gene transfer. These findings suggest that the genetic background of the attenuation can influence the pattern of inflammatory immune response to Salmonella infection.

  1. Activity-dependent accumulation of calcium in Purkinje cell dendritic spines.

    OpenAIRE

    Andrews, S.B.; Leapman, R D; Landis, D M; Reese, T S

    1988-01-01

    The calcium content of synapses of parallel fibers on Purkinje cell dendritic spines was determined by electron probe x-ray microanalysis of freeze-dried cryosections from directly frozen slices of mouse cerebellar cortex. In fresh slices frozen within 20-30 sec of excision, calcium concentrations ranging from 0.8 to 18.6 mmol/kg of dry weight were measured in cisterns of smooth endoplasmic reticulum within Purkinje cell dendritic spines. The average calcium content of spine cisterns in rapid...

  2. A single-step route for large-scale synthesis of core-shell palladium@platinum dendritic nanocrystals/reduced graphene oxide with enhanced electrocatalytic properties

    Science.gov (United States)

    Liu, Qi; Xu, Yan-Ru; Wang, Ai-Jun; Feng, Jiu-Ju

    2016-01-01

    In this report, a facile, seed-less and single-step method is developed for large-scale synthesis of core-shell Pd@Pt dendritic nanocrystals anchored on reduced graphene oxide (Pd@Pt DNC/rGO) under mild conditions. Poly(ethylene oxide) is employed as a structure-directing and stabilizing agent. Compared with commercial Pt/C (20 wt%) and Pd/C (20 wt%) catalysts, the as-obtained nanocomposite has large electrochemically active surface area (114.15 m2gmetal-1), and shows superior catalytic activity and stability with the mass activities of 1210.0 and 1128.5 mAmg metal-1 for methanol and ethanol oxidation, respectively. The improved catalytic activity is mainly the consequence of the synergistic effects between Pd and Pt of the dendritic structures, as well as rGO as a support.

  3. Cigarette smoke promotes dendritic cell accumulation in COPD; a Lung Tissue Research Consortium study

    Directory of Open Access Journals (Sweden)

    Yi Eunhee S

    2010-04-01

    Full Text Available Abstract Background Abnormal immune responses are believed to be highly relevant in the pathogenesis of chronic obstructive pulmonary disease (COPD. Dendritic cells provide a critical checkpoint for immunity by their capacity to both induce and suppress immunity. Although evident that cigarette smoke, the primary cause of COPD, significantly influences dendritic cell functions, little is known about the roles of dendritic cells in the pathogenesis of COPD. Methods The extent of dendritic cell infiltration in COPD tissue specimens was determined using immunohistochemical localization of CD83+ cells (marker of matured myeloid dendritic cells, and CD1a+ cells (Langerhans cells. The extent of tissue infiltration with Langerhans cells was also determined by the relative expression of the CD207 gene in COPD versus control tissues. To determine mechanisms by which dendritic cells accumulate in COPD, complimentary studies were conducted using monocyte-derived human dendritic cells exposed to cigarette smoke extract (CSE, and dendritic cells extracted from mice chronically exposed to cigarette smoke. Results In human COPD lung tissue, we detected a significant increase in the total number of CD83+ cells, and significantly higher amounts of CD207 mRNA when compared with control tissue. Human monocyte-derived dendritic cells exposed to CSE (0.1-2% exhibited enhanced survival in vitro when compared with control dendritic cells. Murine dendritic cells extracted from mice exposed to cigarette smoke for 4 weeks, also demonstrated enhanced survival compared to dendritic cells extracted from control mice. Acute exposure of human dendritic cells to CSE induced the cellular pro-survival proteins heme-oxygenase-1 (HO-1, and B cell lymphoma leukemia-x(L (Bcl-xL, predominantly through oxidative stress. Although activated human dendritic cells conditioned with CSE expressed diminished migratory CCR7 expression, their migration towards the CCR7 ligand CCL21 was not

  4. Nanomaterial-dependent immunoregulation of dendritic cells and its effects on biological activities of contraceptive nanovaccines.

    Science.gov (United States)

    Xu, Pingping; Tang, Shuai; Jiang, Luping; Yang, Lihua; Zhang, Dinglin; Feng, Shibin; Zhao, Tingting; Dong, Yajun; He, Wei; Wang, Ruibing; Zhang, Jianxiang; Liang, Zhiqing

    2016-03-10

    Nanovehicles are promising delivery systems for various vaccines. Nevertheless, different biophysicochemical properties of nanoparticles (NPs), dominating their in vitro and in vivo performances for vaccination, remain unclear. We attempted to elucidate the effects of NPs and their pH-sensitivity on in vitro and in vivo efficacy of resulting prophylactic nanovaccines containing a contraceptive peptide (FSHR). To this end, pH-responsive and non-responsive nanovaccines were produced using acetalated β-cyclodextrin (Ac-bCD) and poly(lactic-co-glycolic acid) (PLGA), respectively. Meanwhile, FSHR derived from an epitope of the follicle-stimulating hormone receptor was used as the model antigen. FSHR-containing Ac-bCD and PLGA NPs were successfully prepared by a nanoemulsion technique, leading to well-shaped nanovaccines with high loading efficiency. The pH-sensitivity of Ac-bCD and PLGA nanovaccines was examined by in vitro hydrolysis and antigen release studies. Nanovaccines could be effectively engulfed by dendritic cells (DCs) via endocytosis in both dose and time dependent manners, and their intracellular trafficking was closely related to the pH-sensitivity of the carrier materials. Furthermore, nanovaccines could induce the secretion of inflammatory cytokines by DCs and T cells co-cultured with the stimulated DCs. In vivo evaluations demonstrated that nanovaccines were more potent than that based on the complete Freund's adjuvant, with respect to inducing anti-FSHR antibody, reducing the sperm count, inhibiting the sperm motility, and increasing the teratosperm rate. Immunization of male mice with nanovaccines notably decreased the parturition incidence of the mated females. Consequently, both in vitro and in vivo activities of FSHR could be considerably augmented by NPs. More importantly, our studies indicated that the pH-responsive nanovaccine was not superior over the non-responsive counterpart for the examined peptide antigen.

  5. Neutrophil extracellular traps downregulate lipopolysaccharide-induced activation of monocyte-derived dendritic cells.

    Science.gov (United States)

    Barrientos, Lorena; Bignon, Alexandre; Gueguen, Claire; de Chaisemartin, Luc; Gorges, Roseline; Sandré, Catherine; Mascarell, Laurent; Balabanian, Karl; Kerdine-Römer, Saadia; Pallardy, Marc; Marin-Esteban, Viviana; Chollet-Martin, Sylvie

    2014-12-01

    Polymorphonuclear neutrophils (PMN) play a central role in inflammation and participate in its control, notably by modulating dendritic cell (DC) functions via soluble mediators or cell-cell contacts. Neutrophil extracellular traps (NETs) released by PMN could play a role in this context. To evaluate NET effects on DC maturation, we developed a model based on monocyte-derived DC (moDC) and calibrated NETs isolated from fresh human PMN. We found that isolated NETs alone had no discernable effect on moDC. In contrast, they downregulated LPS-induced moDC maturation, as shown by decreased surface expression of HLA-DR, CD80, CD83, and CD86, and by downregulated cytokine production (TNF-α, IL-6, IL-12, IL-23), with no increase in the expression of tolerogenic DC genes. Moreover, the presence of NETs during moDC maturation diminished the capacity of these moDC to induce T lymphocyte proliferation in both autologous and allogeneic conditions, and modulated CD4(+) T lymphocyte polarization by promoting the production of Th2 cytokines (IL-5 and IL-13) and reducing that of Th1 and Th17 cytokines (IFN-γ and IL-17). Interestingly, the expression and activities of the lymphoid chemokine receptors CCR7 and CXCR4 on moDC were not altered when moDC matured in the presence of NETs. Together, these findings reveal a new role for NETs in adaptive immune responses, modulating some moDC functions and thereby participating in the control of inflammation.

  6. Whole Body Irradiation Induces Cutaneous Dendritic Cells Depletion via NF-κB Activation

    Directory of Open Access Journals (Sweden)

    Yanyong Yang

    2013-07-01

    Full Text Available Background: Effect of ionizing radiation on cutaneous dendritic cells (cDC is critical to its influence on immune status of the skin, which plays an important role in the progression and recovery of radiation skin sickness. This study was to study the influence of whole body irradiation (WBI on the cDC. Methods: Density of epidermal and dermal DC was determined with a fluorescent microscopy and the DC numbers in lymph node were measured by flow cytometry. A FITC induced migration assay was also used to study the migration of DC. The expressions of cytokines and chemokines were evaluated by Realtime PCR, and the protein level of was measured by Western blot. Results: WBI caused depletion of cDC in epidermal as well as dermal and augmented FITC-induced migration of DC to the draining lymph node (LN. The number of DC migrated from ear explants to the CCL19-containing medium also increased after exposure to WBI. It was also found that WBI increased mRNA level of CCL19/CCL21 as well as CCR7 in LN and skin tissue. The expressions of TNFa, IL-1a, IL-1ß, and IL-6 in skin tissues were also greatly induced by WBI in a dose dependent manner. Finally, we found that WBI induced translocation of nuclear factor κB (NF-κB and that the radiation-induced migration of DC was blocked by NF-κB inhibitor or TLR4 knockout. Conclusion: WBI caused cDC depletion through induction of DC migration to the draining LN, which might result from the activation of NF-κB and the induction of inflammatory microenvironment within the skin.

  7. Activity-based anorexia has differential effects on apical dendritic branching in dorsal and ventral hippocampal CA1.

    Science.gov (United States)

    Chowdhury, Tara G; Barbarich-Marsteller, Nicole C; Chan, Thomas E; Aoki, Chiye

    2014-11-01

    Anorexia nervosa (AN) is an eating disorder to which adolescent females are particularly vulnerable. Like AN, activity-based anorexia (ABA), a rodent model of AN, results in elevation of stress hormones and has genetic links to anxiety disorders. The hippocampus plays a key role in the regulation of anxiety and responds with structural changes to hormones and stress, suggesting that it may play a role in AN. The hippocampus of ABA animals exhibits increased brain-derived neurotrophic factor and increased GABA receptor expression, but the structural effects of ABA have not been studied. We used Golgi staining of neurons to determine whether ABA in female rats during adolescence results in structural changes to the apical dendrites in hippocampal CA1 and contrasted to the effects of food restriction (FR) and exercise (EX), the environmental factors used to induce ABA. In the dorsal hippocampus, which preferentially mediates spatial learning and cognition, cells of ABA animals had less total dendritic length and fewer dendritic branches in stratum radiatum (SR) than in control (CON). In the ventral hippocampus, which preferentially mediates anxiety, ABA evoked more branching in SR than CON. In both dorsal and ventral regions, the main effect of exercise was localized to the SR while the main effect of food restriction occurred in the stratum lacunosum-moleculare. Taken together with data on spine density, these results indicate that ABA elicits pathway-specific changes in the hippocampus that may underlie the increased anxiety and reduced behavioral flexibility observed in ABA.

  8. Type I Interferon Receptor Deficiency in Dendritic Cells Facilitates Systemic Murine Norovirus Persistence Despite Enhanced Adaptive Immunity.

    Directory of Open Access Journals (Sweden)

    Timothy J Nice

    2016-06-01

    Full Text Available In order for a virus to persist, there must be a balance between viral replication and immune clearance. It is commonly believed that adaptive immunity drives clearance of viral infections and, thus, dysfunction or viral evasion of adaptive immunity is required for a virus to persist. Type I interferons (IFNs play pleiotropic roles in the antiviral response, including through innate control of viral replication. Murine norovirus (MNoV replicates in dendritic cells (DCs and type I IFN signaling in DCs is important for early control of MNoV replication. We show here that the non-persistent MNoV strain CW3 persists systemically when CD11c positive DCs are unable to respond to type I IFN. Persistence in this setting is associated with increased early viral titers, maintenance of DC numbers, increased expression of DC activation markers and an increase in CD8 T cell and antibody responses. Furthermore, CD8 T cell function is maintained during the persistent phase of infection and adaptive immune cells from persistently infected mice are functional when transferred to Rag1-/- recipients. Finally, increased early replication and persistence are also observed in mixed bone marrow chimeras where only half of the CD11c positive DCs are unable to respond to type I IFN. These findings demonstrate that increased early viral replication due to a cell-intrinsic innate immune deficiency is sufficient for persistence and a functional adaptive immune response is not sufficient for viral clearance.

  9. Activated T cells recruit exosomes secreted by dendritic cells via LFA-1.

    NARCIS (Netherlands)

    Nolte-'t Hoen, E.N.; Buschow, S.I.; Anderton, S.M.; Stoorvogel, W.; Wauben, M.H.M.

    2009-01-01

    Dendritic cells (DCs) are known to secrete exosomes that transfer membrane proteins, like major histocompatibility complex class II, to other DCs. Intercellular transfer of membrane proteins is also observed during cognate interactions between DCs and CD4(+) T cells. The acquired proteins are functi

  10. Natural IgM Switches the Function of Lipopolysaccharide-Activated Murine Bone Marrow-Derived Dendritic Cells to a Regulatory Dendritic Cell That Suppresses Innate Inflammation.

    Science.gov (United States)

    Lobo, Peter I; Schlegel, Kailo H; Bajwa, Amandeep; Huang, Liping; Kurmaeva, Elvira; Wang, Binru; Ye, Hong; Tedder, Thomas F; Kinsey, Gilbert R; Okusa, Mark D

    2015-12-01

    We have previously shown that polyclonal natural IgM protects mice from renal ischemia/reperfusion injury (IRI) by inhibiting the reperfusion inflammatory response. We hypothesized that a potential mechanism involved IgM modulation of dendritic cells (DC), as we observed high IgM binding to splenic DC. To test this hypothesis, we pretreated bone marrow-derived DC (BMDC) with polyclonal murine or human IgM prior to LPS activation and demonstrated that 0.5 × 10(6) IgM/LPS-pretreated BMDC, when injected into wild-type C57BL/6 mice 24 h before renal ischemia, protect mice from developing renal IRI. We show that this switching of LPS-activated BMDC to a regulatory phenotype requires modulation of BMDC function that is mediated by IgM binding to nonapoptotic BMDC receptors. Regulatory BMDC require IL-10 and programmed death 1 as well as downregulation of CD40 and p65 NF-κB phosphorylation to protect in renal IRI. Blocking the programmed death ligand 1 binding site just before i.v. injection of IgM/LPS-pretreated BMDC or using IL-10 knockout BMDC fails to induce protection. Similarly, IgM/LPS-pretreated BMDC are rendered nonprotective by increasing CD40 expression and phosphorylation of p65 NF-κB. How IgM/LPS regulatory BMDC suppress in vivo ischemia-induced innate inflammation remains to be determined. However, we show that suppression is dependent on other in vivo regulatory mechanisms in the host, that is, CD25(+) T cells, B cells, IL-10, and circulating IgM. There was no increase in Foxp3(+) regulatory T cells in the spleen either before or after renal IRI. Collectively, these findings show that natural IgM anti-leukocyte Abs can switch BMDC to a regulatory phenotype despite the presence of LPS that ordinarily induces BMDC maturation.

  11. Vitamin D₃ and monomethyl fumarate enhance natural killer cell lysis of dendritic cells and ameliorate the clinical score in mice suffering from experimental autoimmune encephalomyelitis.

    Science.gov (United States)

    Al-Jaderi, Zaidoon; Maghazachi, Azzam A

    2015-11-13

    Experimental autoimmune encephalomyelitis (EAE) is a CD4⁺ T cell mediated inflammatory demyelinating disease that is induced in mice by administration of peptides derived from myelin proteins. We developed EAE in SJL mice by administration of PLP139-151 peptide. The effect of treating these mice with 1α,25-Dihydroxyvitamin D₃ (vitamin D₃), or with monomethyl fumarate (MMF) was then examined. We observed that both vitamin D₃ and MMF inhibited and/or prevented EAE in these mice. These findings were corroborated with isolating natural killer (NK) cells from vitamin D₃-treated or MMF-treated EAE mice that lysed immature or mature dendritic cells. The results support and extend other findings indicating that an important mechanism of action for drugs used to treat multiple sclerosis (MS) is to enhance NK cell lysis of dendritic cells.

  12. Activation of the aryl hydrocarbon receptor affects activation and function of human monocyte-derived dendritic cells.

    Science.gov (United States)

    Wang, C; Ye, Z; Kijlstra, A; Zhou, Y; Yang, P

    2014-08-01

    Aryl hydrocarbon receptor (AhR) is well known for mediating the toxic effects of dioxin-containing pollutants, but has also been shown to be involved in the natural regulation of the immune response. In this study, we investigated the effect of AhR activation by its endogenous ligands 6-formylindolo[3,2-b]carbazole (FICZ) and 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) on the differentiation, maturation and function of monocyte-derived DCs in Behçet's disease (BD) patients. In this study, we showed that AhR activation by FICZ and ITE down-regulated the expression of co-stimulatory molecules including human leucocyte antigen D-related (HLA-DR), CD80 and CD86, while it had no effect on the expression of CD83 and CD40 on DCs derived from BD patients and normal controls. Lipopolysaccharide (LPS)-treated dendritic cells (DCs) from active BD patients showed a higher level of interleukin (IL)-1β, IL-6, IL-23 and tumour necrosis factor (TNF)-α production. FICZ or ITE significantly inhibited the production of IL-1β, IL-6, IL-23 and TNF-α, but induced IL-10 production by DCs derived from active BD patients and normal controls. FICZ or ITE-treated DCs significantly inhibited the T helper type 17 (Th17) and Th1 cell response. Activation of AhR either by FICZ or ITE inhibits DC differentiation, maturation and function. Further studies are needed to investigate whether manipulation of the AhR pathway may be used to treat BD or other autoimmune diseases.

  13. DC-SIGN-mediated infectious synapse formation enhances X4 HIV-1 transmission from dendritic cells to T cells.

    Science.gov (United States)

    Arrighi, Jean-François; Pion, Marjorie; Garcia, Eduardo; Escola, Jean-Michel; van Kooyk, Yvette; Geijtenbeek, Teunis B; Piguet, Vincent

    2004-11-15

    Dendritic cells (DCs) are essential for the early events of human immunodeficiency virus (HIV) infection. Model systems of HIV sexual transmission have shown that DCs expressing the DC-specific C-type lectin DC-SIGN capture and internalize HIV at mucosal surfaces and efficiently transfer HIV to CD4+ T cells in lymph nodes, where viral replication occurs. Upon DC-T cell clustering, internalized HIV accumulates on the DC side at the contact zone (infectious synapse), between DCs and T cells, whereas HIV receptors and coreceptors are enriched on the T cell side. Viral concentration at the infectious synapse may explain, at least in part, why DC transmission of HIV to T cells is so efficient.Here, we have investigated the role of DC-SIGN on primary DCs in X4 HIV-1 capture and transmission using small interfering RNA-expressing lentiviral vectors to specifically knockdown DC-SIGN. We demonstrate that DC-SIGN- DCs internalize X4 HIV-1 as well as DC-SIGN+ DCs, although binding of virions is reduced. Strikingly, DC-SIGN knockdown in DCs selectively impairs infectious synapse formation between DCs and resting CD4+ T cells, but does not prevent the formation of DC-T cells conjugates. Our results demonstrate that DC-SIGN is required downstream from viral capture for the formation of the infectious synapse between DCs and T cells. These findings provide a novel explanation for the role of DC-SIGN in the transfer and enhancement of HIV infection from DCs to T cells, a crucial step for HIV transmission and pathogenesis.

  14. Vortioxetine promotes early changes in dendritic morphology compared to fluoxetine in rat hippocampus.

    Science.gov (United States)

    Chen, Fenghua; du Jardin, Kristian Gaarn; Waller, Jessica A; Sanchez, Connie; Nyengaard, Jens R; Wegener, Gregers

    2016-02-01

    Preclinical studies reveal that the multimodal antidepressant vortioxetine enhances long-term potentiation and dendritic branching compared to a selective serotonin reuptake inhibitor (SSRI). In the present study, we investigated vortioxetine׳s effects on spines and dendritic morphology in rat hippocampus at two time points compared to the SSRI, fluoxetine. Rats were dosed for 1 and 4 weeks with vortioxetine and fluoxetine at doses relevant for antidepressant activity. Dendritic morphology of pyramidal neurons (i.e., dendritic length, dendritic branch, spine number and density, and Sholl analysis) was examined in Golgi-stained sections from hippocampal CA1. After 1 week of treatment, vortioxetine significantly increased spine number (apical and basal dendrites), spine density (only basal), dendritic length (only apical), and dendritic branch number (apical and basal), whereas fluoxetine had no effect. After 4 weeks of treatment, vortioxetine significantly increased all measures of dendritic spine morphology as did fluoxetine except for spine density of basal dendrites. The number of intersections in the apical and basal dendrites was also significantly increased for both treatments after 4 weeks compared to control. In addition, 4 weeks of vortioxetine treatment, but not fluoxetine, promoted a decrease in spine neck length. In conclusion, 1-week vortioxetine treatment induced changes in spine number and density and dendritic morphology, whereas an equivalent dose of fluoxetine had no effects. Decreased spine neck length following 4-week vortioxetine treatment suggests a transition to mature spine morphology. This implies that vortioxetine׳s effects on spine and dendritic morphology are mediated by mechanisms that go beyond serotonin reuptake inhibition.

  15. Human monocytes undergo excessive apoptosis following temozolomide activating the ATM/ATR pathway while dendritic cells and macrophages are resistant.

    Directory of Open Access Journals (Sweden)

    Martina Bauer

    Full Text Available Immunodeficiency is a severe therapy-limiting side effect of anticancer chemotherapy resulting from sensitivity of immunocompetent cells to DNA damaging agents. A central role in the immune system is played by monocytes that differentiate into macrophages and dendritic cells (DCs. In this study we compared human monocytes isolated from peripheral blood and cytokine matured macrophages and DCs derived from them and assessed the mechanism of toxicity of the DNA methylating anticancer drug temozolomide (TMZ in these cell populations. We observed that monocytes, but not DCs and macrophages, were highly sensitive to the killing effect of TMZ. Studies on DNA damage and repair revealed that the initial DNA incision was efficient in monocytes while the re-ligation step of base excision repair (BER can not be accomplished, resulting in an accumulation of DNA single-strand breaks (SSBs. Furthermore, monocytes accumulated DNA double-strand breaks (DSBs following TMZ treatment, while DCs and macrophages were able to repair DSBs. Monocytes lack the DNA repair proteins XRCC1, ligase IIIα and PARP-1 whose expression is restored during differentiation into macrophages and DCs following treatment with GM-CSF and GM-CSF plus IL-4, respectively. These proteins play a key role both in BER and DSB repair by B-NHEJ, which explains the accumulation of DNA breaks in monocytes following TMZ treatment. Although TMZ provoked an upregulation of XRCC1 and ligase IIIα, BER was not enhanced likely because PARP-1 was not upregulated. Accordingly, inhibition of PARP-1 did not sensitize monocytes, but monocyte-derived DCs in which strong PARP activation was observed. TMZ induced in monocytes the DNA damage response pathways ATM-Chk2 and ATR-Chk1 resulting in p53 activation. Finally, upon activation of the Fas-receptor and the mitochondrial pathway apoptosis was executed in a caspase-dependent manner. The downregulation of DNA repair in monocytes, resulting in their selective

  16. Generation of clinical grade dendritic cells with capacity to produce biologically active IL-12p70

    Directory of Open Access Journals (Sweden)

    Bigalke Iris

    2007-04-01

    Full Text Available Abstract Background For optimal T cell activation it is desirable that dendritic cells (DCs display peptides within MHC molecules as signal 1, costimulatory molecules as signal 2 and, in addition, produce IL-12p70 as signal 3. IL-12p70 polarizes T cell responses towards CD4+ T helper 1 cells, which then support the development of CD8+ cytotoxic T lymphocytes. We therefore developed new maturation cocktails allowing DCs to produce biologically active IL-12p70 for large-scale cancer vaccine development. Methods After elutriation of leukapheresis products in a closed bag system, enriched monocytes were cultured with GM-CSF and IL-4 for six days to generate immature DCs that were then matured with cocktails, containing cytokines, interferon-gamma, prostaglandin E2, and a ligand for Toll-like receptor 8, with or without poly (I:C. Results Mature DCs expressed appropriate maturation markers and the lymph node homing chemokine receptor, CCR7. They retained full maturity after culture for two days without maturation cocktails and following cryopreservation. TLR ligand stimulation induced DCs capable of secreting IL-12p70 in primary cultures and after one day of coculture with CD40L-expressing fibroblasts, mimicking an encounter with T cells. DCs matured with our new cocktails containing TLR8 ligand, with or without poly (I:C, induced alloresponses and stimulated virus-specific T cells after peptide-pulsing. DCs matured in cocktails containing TLR8 ligand without poly (I:C could also be loaded with RNA as a source of antigen, whereas DCs matured in cocktails containing poly (I:C were unable to express proteins following RNA transfer by electroporation. Conclusion Our new maturation cocktails allowed easy DC harvesting, stable maturation and substantial recoveries of mature DCs after cryopreservation. Our procedure for generating DCs is easily adaptable for GMP-compliance and yields IL-12p70-secreting DCs suitable for development of cancer vaccines using

  17. Dendritic Tip-on Polytriazine-Based Carbon Nitride Photocatalyst with High Hydrogen Evolution Activity

    KAUST Repository

    Bhunia, Manas Kumar

    2015-11-23

    Developing stable, ubiquitous and efficient water-splitting photocatalyst material that has extensive absorption in the visible-light range is desired for a sustainable solar energy-conversion device. We herein report a triazine-based carbon nitride (CN) material with different C/N ratios achieved by varying the monomer composition ratio between melamine (Mel) and 2,4,6-triaminopyrimidine (TAP). The CN material with a different C/N ratio was obtained through a two-step synthesis protocol: starting with the solution state dispersion of the monomers via hydrogen-bonding supramolecular aggregate, followed by a salt-melt high temperature polycondensation. This protocol ensures the production of a highly crystalline polytriazine imide (PTI) structure con-sisting of a copolymerized Mel-TAP network. The observed bandgap narrowing with an increasing TAP/Mel ratio is well simulated by density functional theory (DFT) calculations, revealing a positive shift in the valence band upon substitution of N with CH in the aromatic rings. Increasing the TAP amount could not maintain the crystalline PTI structure, consistent with DFT calculation showing the repulsion associated with additional C-H introduced in the aromatic rings. Due to the high exciton binding energy calculated by DFT for the obtained CN, the cocatalyst must be close to any portion of the material to assist the separation of excit-ed charge carriers for an improved photocatalytic performance. The photocatalytic activity was improved by providing a dendritic tip-on-like shape grown on a porous fibrous silica KCC-1 spheres, and highly dispersed Pt nanoparticles (<5 nm) were photodepos-ited to introduce heterojunction. As a result, the Pt/CN/KCC-1 photocatalyst exhibited an apparent quantum efficiency (AQE) as high as 22.1 ± 3% at 400 nm and the silica was also beneficial for improving photocatalytic stability. The results obtained by time-resolved transient absorption spectroscopy measurements were consistent with

  18. The serotonin receptor 5-HT₇R regulates the morphology and migratory properties of dendritic cells.

    Science.gov (United States)

    Holst, Katrin; Guseva, Daria; Schindler, Susann; Sixt, Michael; Braun, Armin; Chopra, Himpriya; Pabst, Oliver; Ponimaskin, Evgeni

    2015-08-01

    Dendritic cells are potent antigen-presenting cells endowed with the unique ability to initiate adaptive immune responses upon inflammation. Inflammatory processes are often associated with an increased production of serotonin, which operates by activating specific receptors. However, the functional role of serotonin receptors in regulation of dendritic cell functions is poorly understood. Here, we demonstrate that expression of serotonin receptor 5-HT7 (5-HT7R) as well as its downstream effector Cdc42 is upregulated in dendritic cells upon maturation. Although dendritic cell maturation was independent of 5-HT7R, receptor stimulation affected dendritic cell morphology through Cdc42-mediated signaling. In addition, basal activity of 5-HT7R was required for the proper expression of the chemokine receptor CCR7, which is a key factor that controls dendritic cell migration. Consistent with this, we observed that 5-HT7R enhances chemotactic motility of dendritic cells in vitro by modulating their directionality and migration velocity. Accordingly, migration of dendritic cells in murine colon explants was abolished after pharmacological receptor inhibition. Our results indicate that there is a crucial role for 5-HT7R-Cdc42-mediated signaling in the regulation of dendritic cell morphology and motility, suggesting that 5-HT7R could be a new target for treatment of a variety of inflammatory and immune disorders.

  19. Beta 2-adrenergic receptor activation enhances neurogenesis in Alzheimer’s disease mice

    Institute of Scientific and Technical Information of China (English)

    Gao-shang Chai; Yang-yang Wang; Amina Yasheng; Peng Zhao

    2016-01-01

    Impaired hippocampal neurogenesis is one of the early pathological features of Alzheimer’s disease. Enhancing adult hippocampal neuro-genesis has been pursued as a potential therapeutic strategy for Alzheimer’s disease. Recent studies have demonstrated that environmental novelty activates β2-adrenergic signaling and prevents the memory impairment induced by amyloid-β oligomers. Here, we hypothesized that β2-adrenoceptor activation would enhance neurogenesis and ameliorate memory deifcits in Alzheimer’s disease. To test this hypothe-sis, we investigated the effects and mechanisms of action of β2-adrenoceptor activation on neurogenesis and memory in amyloid precursor protein/presenilin 1 (APP/PS1) mice using the agonist clenbuterol (intraperitoneal injection, 2 mg/kg). We found that β2-adrenoceptor ac-tivation enhanced hippocampal neurogenesis, ameliorated memory deifcits, and increased dendritic branching and the density of dendritic spines. hTese effects were associated with the upregulation of postsynaptic density 95, synapsin 1 and synaptophysin in APP/PS1 mice. Furthermore, β2-adrenoceptor activation decreased cerebral amyloid plaques by decreasing APP phosphorylation at hTr668. hTese ifndings suggest that β2-adrenoceptor activation enhances neurogenesis and ameliorates memory deifcits in APP/PS1 mice.

  20. Enhancement of Extracts from Celastrus orbiculatus on Maturation and Function of Dendritic Cells in vitro and in vivo

    Institute of Scientific and Technical Information of China (English)

    QIAN Ya-yun; ZHANG Hua; YUAN Lin; HOU Ying; LIU Wei-wei; LIU Yan-qing

    2010-01-01

    Objective To examine the immunoregulation of Celastrus orbiculatus extracts(COE),a traditional Chinese medicine,on maturation and function of dendritic cells(DCs)in vitro and in vivo.Methods In vitro,after treated with COE indifferent nontoxic concentrations(0,10,20,40,80,and 160 μg/mL)for 5 d,the surface immunological molecules andcytokine secretion of mice bone marrow-derived DCs in response to COE were analyzed by flow cytometric analysis(FACS)and enzyme linked immunosorbent assay(ELISA),respectively.In vivo,mouse hepatoma cells(Hepal-6,1 ×106)were injected sc and were treated with different dosages of COE(10,20 or 40 mg/kg/d).Effects on tumor growth were determined by tumor volume and histology analysis after 28 d administration of COE.The relative proportions ofmature DCs and CD8+ T cells were measured in mononuclear cells that had been isolated from spleen by FACS.Results COE stimulated IL-2 and IFN-γ secretion of DCs,simultaneously enhanced the maturation of DCs byenhancing immunological molecule(CD40,CDS0,CD86,H-2Kb,and I-Ab)expression in a dose-dependent manner.Furthermore,the chcmotactic responses of DCs were significantly higher in COE-treated than untreated DCs,in association with higher chcmokine receptor 7 expression.Furthermore,COE increased DCs produce IFN-γ and IL-2 ina dose-dependent manner when the concentration of COE less than 40 μg/mL,decreased DCs produce IL-10 and IL-4also in a dose-dependent manner.In in vivo studies,COE can not only suppress growth of malignant hepatocellularcarcinomas but also stimulate maturation of DCs,associated with strongly enhanced CD8+ CTL responses.ConclusionThese data provide new insight into the mechanism of action of COE and indicate that the stimulation of maturation andfunction of DCs by COE contributes to its immunoregulatory effects.

  1. Herbal preparation (HemoHIM) enhanced functional maturation of bone marrow-derived dendritic cells mediated toll-like receptor 4

    OpenAIRE

    Lee, Sung-Ju; Kim, Jong-Jin; Kang, Kyung-Yun; Hwang, Yun-Ho; Jeong, Gil-Yeon; Jo, Sung-Kee; Jung, Uhee; Park, Hae-Ran; Yee, Sung-Tae

    2016-01-01

    Background HemoHIM, which is an herbal preparation of three edible herbs (Angelicam gigas Nakai, Cnidium offinale Makino, and Peaonia japonica Miyabe), is known to have various biological and immunological activities, but the modulatory effects of this preparation on dendritic cells (DCs)-mediated immune responses have not been examined previously. DCs are a unique group of white blood cells that initiate primary immune responses by capturing, processing, and presenting antigens to T cells. R...

  2. Physical Exercise and Antidepressants Enhance BDNF Targeting in Hippocampal CA3 Dendrites: Further Evidence of a Spatial Code for BDNF Splice Variants

    OpenAIRE

    Baj, Gabriele; D'Alessandro, Valentina; Musazzi, Laura; Mallei, Alessandra; Sartori, Cesar R; Sciancalepore, Marina; Tardito, Daniela; Langone, Francesco; Popoli, Maurizio; Tongiorgi, Enrico

    2012-01-01

    Brain-derived neurotrophic factor (BDNF) is encoded by multiple BDNF transcripts, whose function is unclear. We recently showed that a subset of BDNF transcripts can traffic into distal dendrites in response to electrical activity, while others are segregated into the somatoproximal domains. Physical exercise and antidepressant treatments exert their beneficial effects through upregulation of BDNF, which is required to support survival and differentiation of newborn dentate gyrus (DG) neurons...

  3. P2X7R activation drives distinct IL-1 responses in dendritic cells compared to macrophages

    OpenAIRE

    Englezou, Pavlos C.; Rothwell, Simon W.; Ainscough, Joseph S.; Brough, David; Landsiedel, Robert; Verkhratsky, Alexei; Kimber, Ian; Dearman, Rebecca J

    2015-01-01

    The P2X7R is a functionally distinct member of the P2X family of non-selective cation channels associated with rapid activation of the inflammasome complex and signalling interleukin (IL)-1β release in macrophages. The main focus of this investigation was to compare P2X7R-driven IL-1 production by primary murine bone marrow derived dendritic cells (BMDC) and macrophages (BMM). P2X7R expression in murine BMDC and BMM at both transcriptional (P2X7A variant) and protein levels was demonstrated....

  4. Short-term environmental enrichment enhances adult neurogenesis, vascular network and dendritic complexity in the hippocampus of type 1 diabetic mice.

    Directory of Open Access Journals (Sweden)

    Juan Beauquis

    Full Text Available BACKGROUND: Several brain disturbances have been described in association to type 1 diabetes in humans. In animal models, hippocampal pathological changes were reported together with cognitive deficits. The exposure to a variety of environmental stimuli during a certain period of time is able to prevent brain alterations and to improve learning and memory in conditions like stress, aging and neurodegenerative processes. METHODOLOGY/PRINCIPAL FINDINGS: We explored the modulation of hippocampal alterations in streptozotocin-induced type 1 diabetic mice by environmental enrichment. In diabetic mice housed in standard conditions we found a reduction of adult neurogenesis in the dentate gyrus, decreased dendritic complexity in CA1 neurons and a smaller vascular fractional area in the dentate gyrus, compared with control animals in the same housing condition. A short exposure -10 days- to an enriched environment was able to enhance proliferation, survival and dendritic arborization of newborn neurons, to recover dendritic tree length and spine density of pyramidal CA1 neurons and to increase the vascular network of the dentate gyrus in diabetic animals. CONCLUSIONS/SIGNIFICANCE: The environmental complexity seems to constitute a strong stimulator competent to rescue the diabetic brain from neurodegenerative progression.

  5. A facile approach to prepare silicon-based Pt-Ag tubular dendritic nano-forests (tDNFs) for solar-light-enhanced methanol oxidation reaction

    Science.gov (United States)

    Lin, Chun-Ting; Shiao, Ming-Hua; Chang, Mao-Nan; Chu, Nancy; Chen, Yu-Wei; Peng, Yu-Hsuan; Liao, Bo-Huei; Huang, Hung Ji; Hsiao, Chien-Nan; Tseng, Fan-Gang

    2015-02-01

    In this paper, a facile two-step Galvanic replacement reaction (GRR) is proposed to prepare Pt-Ag tubular dendritic nano-forests (tDNFs) in ambient condition for enhancing methanol oxidation reaction (MOR) under solar illumination. In the first GRR, a homogeneous layer of silver dendritic nano-forests (DNFs) with 10 μm in thickness was grown on Si wafer in 5 min in silver nitride (AgNO3) and buffer oxide etchant (BOE) solution. In the second GRR, we utilized chloroplatinic acid (H2PtCl6) as the precursor for platinum (Pt) deposition to further transform the prepared Ag DNFs into Pt-Ag tDNFs. The catalytic performance and solar response of the Pt-Ag tDNFs toward methanol electro-oxidation are also studied by cyclic voltammetry (CV) and chronoamperometry (CA). The methanol oxidation current was boosted by 6.4% under solar illumination on the Pt-Ag tDNFs due to the induced localized surface plasmon resonance (LSPR) on the dendritic structure. Current results provide a cost-effective and facile approach to prepare solar-driven metallic electrodes potentially applicable to photo-electro-chemical fuel cells.

  6. Antitumour activities of cytokine-induced killer cells and dendritic cells in vitro and in vivo

    Institute of Scientific and Technical Information of China (English)

    ZHANG Song; JIANG Shu-juan; ZHANG Cai-qing; WANG Hong-mei; BAI Chun-xue

    2005-01-01

    @@ Solid tumour cells show a resistance to immunological effector cells in vitro.1 The resistance may be one reason why these tumours withstand immunotherapeutic approaches in humans.Dendritic cells (DC) play an important role in the immune response to tumour associated antigens in humans.DC in the periphery capture and process antigens,express lymphocyte costimulatory molecules,migrate to lymphoid organs and secrete cytokines to initiate immune response.

  7. Low-Dose Cyclophosphamide Synergizes with Dendritic Cell-Based Immunotherapy in Antitumor Activity

    Directory of Open Access Journals (Sweden)

    Joris D. Veltman

    2010-01-01

    Full Text Available Clinical immunotherapy trials like dendritic cell-based vaccinations are hampered by the tumor's offensive repertoire that suppresses the incoming effector cells. Regulatory T cells are instrumental in suppressing the function of cytotoxic T cells. We studied the effect of low-dose cyclophosphamide on the suppressive function of regulatory T cells and investigated if the success rate of dendritic cell immunotherapy could be improved. For this, mesothelioma tumor-bearing mice were treated with dendritic cell-based immunotherapy alone or in combination with low-dose of cyclophosphamide. Proportions of regulatory T cells and the cytotoxic T cell functions at different stages of disease were analyzed. We found that low-dose cyclophosphamide induced beneficial immunomodulatory effects by preventing the induction of Tregs, and as a consequence, cytotoxic T cell function was no longer affected. Addition of cyclophosphamide improved immunotherapy leading to an increased median and overall survival. Future studies are needed to address the usefulness of this combination treatment for mesothelioma patients.

  8. Comparison The Effects of Two Monocyte Isolation Methods,Plastic Adherence and Magnetic Activated Cell Sorting Methods,on Phagocytic Activity of Generated Dendritic Cells

    Directory of Open Access Journals (Sweden)

    Behnaz Asadi

    2013-01-01

    Full Text Available Objective: It is believed that monocyte isolation methods and maturation factors affect the phenotypic and functional characteristics of resultant dendritic cells (DC. In the present study, we compared two monocyte isolation methods, including plastic adherence-dendritic cells (Adh-DC and magnetic activated cell sorting- dendritic cells (MACS-DC, and their effects on phagocytic activity of differentiated immature DCs (immDCs.Materials and Methods: In this experimental study, immDCs were generated from plastic adherence and MACS isolated monocytes in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF and interleukin 4 (IL-4 in five days. The phagocytic activity of immDCs was analyzed by fluorescein isothiocyanate (FITC-conjugated latex bead using flow cytometry. One way ANOVA test was used for statistical analysis of differences among experimental groups, including Adh-DC and MACS-DC groups.Results: We found that phagocytic activity of Adh-DC was higher than MACS-DC, whereas the mean fluorescence intensity (MFI of phagocytic cells was higher in MACS-DC (p<0.05.Conclusion: We concluded that it would be important to consider phagocytosis parameters of generated DCs before making any decision about monocyte isolation methods to have fully functional DCs.

  9. Enhanced Dendritic Cell-Mediated Antigen-Specific CD4+ T Cell Responses: IFN-Gamma Aids TLR Stimulation

    Directory of Open Access Journals (Sweden)

    Kuo-Ching Sheng

    2013-01-01

    Full Text Available Phenotypic maturation and T cell stimulation are two functional attributes of DCs critical for immune induction. The combination of antigens, including those from cancer, with Toll-like receptor (TLR ligands induces far superior cellular immune responses compared to antigen alone. In this study, IFN-gamma treatment of bone marrow-derived DC, followed by incubation with the TLR2, TLR4, or TLR9 agonists, enhanced DC activation compared to TLR ligation alone. Most notably, the upregulation of CD40 with LPS stimulation and CD86 with CpG stimulation was observed in in vitro cultures. Similarly, IFN-gamma coinjected with TLR ligands was able to promote DC activation in vivo, with DCs migrating from the site of immunization to the popliteal lymph nodes demonstrating increased expression of CD80 and CD86. The heightened DC activation translated to a drastic increase in T cell stimulatory capacity in both antigen independent and antigen dependent fashions. This is the first time that IFN-gamma has been shown to have a combined effect with TLR ligation to enhance DC activation and function. The results demonstrate the novel use of IFN-gamma together with TLR agonists to enhance antigen-specific T cell responses, for applications in the development of enhanced vaccines and drug targets against diseases including cancer.

  10. Immunization with Dendritic Cells Pulsed ex vivo with Recombinant Chlamydial Protease-Like Activity Factor Induces Protective Immunity Against Genital Chlamydia muridarum Challenge

    Directory of Open Access Journals (Sweden)

    Bernard eArulanandam

    2011-12-01

    Full Text Available We have shown that immunization with soluble recombinant (r chlamydial protease-like activity factor (rCPAF and a T helper (Th 1 type adjuvant can induce significantly enhanced bacterial clearance and protection against Chlamydia–induced pathological sequelae in the genital tract. In this study, we investigated the use of bone marrow derived dendritic cells (BMDCs pulsed ex vivo with rCPAF+CpG in an adoptive subcutaneous immunization for the ability to induce protective immunity against genital chlamydial infection. We found that BMDCs pulsed with rCPAF+CpG efficiently up-regulated the expression of activation markers CD86, CD80, CD40 and major histocompatibility complex class II (MHC II, and secreted interleukin-12, but not IL-10 and IL-4. Mice adoptively immunized with rCPAF+CpG-pulsed BMDCs or UV-EB+CpG-pulsed BMDCs produced elevated levels of antigen-specific IFN- and enhanced IgG1 and IgG2a antibodies. Moreover, mice immunized with rCPAF+CpG-pulsed BMDCs or UV-EB+CpG-pulsed BMDCs exhibited significantly reduced genital Chlamydia shedding, accelerated resolution of infection, and reduced oviduct pathology when compared to infected mock-immunized animals. These results suggest that adoptive subcutaneous immunization with ex vivo rCPAF-pulsed BMDCs is an effective approach, comparable to that induced by UV-EB-BMDCs, for inducing robust anti-Chlamydia immunity.

  11. SK2 channel modulation contributes to compartment-specific dendritic plasticity in cerebellar Purkinje cells.

    Science.gov (United States)

    Ohtsuki, Gen; Piochon, Claire; Adelman, John P; Hansel, Christian

    2012-07-12

    Small-conductance Ca(2+)-activated K(+) channels (SK channels) modulate excitability and curtail excitatory postsynaptic potentials (EPSPs) in neuronal dendrites. Here, we demonstrate long-lasting plasticity of intrinsic excitability (IE) in dendrites that results from changes in the gain of this regulatory mechanism. Using dendritic patch-clamp recordings from rat cerebellar Purkinje cells, we find that somatic depolarization or parallel fiber (PF) burst stimulation induce long-term amplification of synaptic responses to climbing fiber (CF) or PF stimulation and enhance the amplitude of passively propagated sodium spikes. Dendritic plasticity is mimicked and occluded by the SK channel blocker apamin and is absent in Purkinje cells from SK2 null mice. Triple-patch recordings from two dendritic sites and the soma and confocal calcium imaging studies show that local stimulation limits dendritic plasticity to the activated compartment of the dendrite. This plasticity mechanism allows Purkinje cells to adjust the SK2-mediated control of dendritic excitability in an activity-dependent manner.

  12. Autometallographic (AMG) technique used for enhancement of the Golgi-Cox staining gives good contrast andhigh resolution of dendrites and spines

    DEFF Research Database (Denmark)

    Orlowski, Dariusz

    Despite the existence of many newer staining methods, Golgi staining still remains the primary method forvisualization of the dendrites and spines. The black deposit in the Golgi-Cox impregnated cells is a Mercuricsulphide, therefore autometallographic (AMG) technique which is used...... for visualization of the metals and metalsulphides/selenides in tissue may be used to enhance the Golgi-Cox staining. We demonstrated accordingly thatuse of AMG enhancement method on the Golgi-Cox staining gives good contrast and high resolution of dendritesand spines. Moreover, this method is cheaper and more...... flexible than conventional enhancement proceduresperformed with commercial photographic developers. The staining procedure is thoroughly described and wedemonstrate with qualitative and quantitative data, how Golgi-Cox immersion time and different AMGenhancement length may influence the staining...

  13. Maturation of dendritic cells by recombinant human CD40L-trimer leads to a homogeneous cell population with enhanced surface marker expression and increased cytokine production

    DEFF Research Database (Denmark)

    Würtzen, P A; Nissen, Mogens Holst; Claesson, M H

    2001-01-01

    Dendritic cells (DC) have been shown to be potent inducers of specific cytotoxic T-cell responses both in vivo and in vitro. Furthermore, exposure to cytokines such as tumour necrosis factor (TNF)-alpha or CD40 triggering changes DC phenotype and cytokine production and may enhance the T...... enhanced by exposure to huCD40LT even compared to TNF-alpha exposure. Only a moderate cytokine production was observed initially, while TNF-alpha addition or CD40 triggering, especially, induced enhanced production of IL-6 and IL-12 p40. Surprisingly, comparable induction of T-cell proliferation by a DC...... marker expression and high production of pro-inflammatory cytokines. In addition, the induction of responses to allo or recall antigens presented by huCD40LT maturated DC was comparable to the responses obtained with the DC maturated through TNF-alpha exposure....

  14. Cadm1-expressing synapses on Purkinje cell dendrites are involved in mouse ultrasonic vocalization activity.

    Directory of Open Access Journals (Sweden)

    Eriko Fujita

    Full Text Available Foxp2(R552H knock-in (KI mouse pups with a mutation related to human speech-language disorders exhibit poor development of cerebellar Purkinje cells and impaired ultrasonic vocalization (USV, a communication tool for mother-offspring interactions. Thus, human speech and mouse USV appear to have a Foxp2-mediated common molecular basis in the cerebellum. Mutations in the gene encoding the synaptic adhesion molecule CADM1 (RA175/Necl2/SynCAM1/Cadm1 have been identified in people with autism spectrum disorder (ASD who have impaired speech and language. In the present study, we show that both Cadm1-deficient knockout (KO pups and Foxp2(R552H KI pups exhibit impaired USV and smaller cerebellums. Cadm1 was preferentially localized to the apical-distal portion of the dendritic arbor of Purkinje cells in the molecular layer of wild-type pups, and VGluT1 level decreased in the cerebellum of Cadm1 KO mice. In addition, we detected reduced immunoreactivity of Cadm1 and VGluT1 on the poorly developed dendritic arbor of Purkinje cells in the Foxp2(R552H KI pups. However, Cadm1 mRNA expression was not altered in the Foxp2(R552H KI pups. These results suggest that although the Foxp2 transcription factor does not target Cadm1, Cadm1 at the synapses of Purkinje cells and parallel fibers is necessary for USV function. The loss of Cadm1-expressing synapses on the dendrites of Purkinje cells may be associated with the USV impairment that Cadm1 KO and Foxp2(R552H KI mice exhibit.

  15. Optimization of Assays to Assess Dendritic Cell Activation and/or Anergy in Ebola Infection.

    Science.gov (United States)

    2012-09-01

    studied entry of EBOV virus -like particles (EVLPs) as a surrogate for live virus , into murine peritoneal cells, because mouse-adapted Ebola viruses are...infection by Ebola and Marburg viruses . Lab Invest 80 (2), 171-186 (2000). 2 Geisbert, T.W. & Hensley, L.E., Ebola virus : new insights into disease...Mahanty, S. et al., Cutting edge: impairment of dendritic cells and adaptive immunity by Ebola and Lassa viruses . J Immunol 170 (6), 2797-2801 (2003). APPENDICES: None

  16. Collagen I-induced dendritic cells activation is regulated by TNF-alpha production through down-regulation of IRF4.

    Science.gov (United States)

    Poudel, Barun; Ki, Hyeon-Hui; Lee, Young-Mi; Kim, Dae-Ki

    2015-03-01

    Previously we have shown that collagen I enhances the maturation and function of dendritic cells (DCs). Inflammatory mediators such as tumour necrosis factor (TNF)- alpha, interleukin (IL)-1 beta and lipopolysaccharide (LPS) are also known to activate DCs. Here we investigated the involvement of TNF-alpha on the collagen I-induced DCs activation. TNF-a neutralization inhibited collagen I-induced IL-12 secretions by DCs. Additionally, we observed suppression of collagen I-induced costimulatory molecules expression along with down-regulation of genes involved in DCs activation pathway. Furthermore, TNF- alpha inhibition upon collagen Istimulation up-regulated the expression of interferon regulatory transcription factor IRF4, when compared to collagen I only treated cells. Collectively, our data demonstrate that collagen I induce TNF- alpha production, which is crucial for the activation and function of DCs, through down-regulation of IRF4, and implicates the importance in development of anti- TNF-alpha therapeutics for several inflammatory diseases.

  17. [Inflammatory dendritic cells].

    Science.gov (United States)

    Segura, Elodie; Amigorena, Sebastian

    2014-01-01

    Dendritic cells are a rare and heterogeneous population of professional antigen-presenting cells. Several murine dendritic cell subpopulations have been identified that differ in their phenotype and functional properties. In the steady state, committed dendritic cell precursors differentiate into lymphoid organ-resident dendritic cells and migratory tissue dendritic cells. During inflammation appears an additional dendritic cell subpopulation that has been termed « inflammatory dendritic cells ». Inflammatory dendritic cells differentiate in situ from monocytes recruited to the site of inflammation. Here, we discuss how mouse inflammatory dendritic cells differ from macrophages and from other dendritic cell populations. Finally, we review recent work on human inflammatory dendritic cells.

  18. Familiar Taste Induces Higher Dendritic Levels of Activity-Regulated Cytoskeleton-Associated Protein in the Insular Cortex than a Novel One

    Science.gov (United States)

    Morin, Jean-Pascal; Quiroz, Cesar; Mendoza-Viveros, Lucia; Ramirez-Amaya, Victor; Bermudez-Rattoni, Federico

    2011-01-01

    The immediate early gene (IEG) "Arc" is known to play an important role in synaptic plasticity; its protein is locally translated in the dendrites where it has been involved in several types of plasticity mechanisms. Because of its tight coupling with neuronal activity, "Arc" has been widely used as a tool to tag behaviorally activated networks.…

  19. Physical exercise and antidepressants enhance BDNF targeting in hippocampal CA3 dendrites: further evidence of a spatial code for BDNF splice variants.

    Science.gov (United States)

    Baj, Gabriele; D'Alessandro, Valentina; Musazzi, Laura; Mallei, Alessandra; Sartori, Cesar R; Sciancalepore, Marina; Tardito, Daniela; Langone, Francesco; Popoli, Maurizio; Tongiorgi, Enrico

    2012-06-01

    Brain-derived neurotrophic factor (BDNF) is encoded by multiple BDNF transcripts, whose function is unclear. We recently showed that a subset of BDNF transcripts can traffic into distal dendrites in response to electrical activity, while others are segregated into the somatoproximal domains. Physical exercise and antidepressant treatments exert their beneficial effects through upregulation of BDNF, which is required to support survival and differentiation of newborn dentate gyrus (DG) neurons. While these DG processes are required for the antidepressant effect, a role for CA1 in antidepressant action has been excluded, and the effect on CA3 neurons remains unclear. Here, we show for the first time that physical exercise and antidepressants induce local increase of BDNF in CA3. Voluntary physical exercise for 28 consecutive days, or 2-week treatment with 10 mg/kg per day fluoxetine or reboxetine, produced a global increase of BDNF mRNA and protein in the neuronal somata of the whole hippocampus and a specific increase of BDNF in dendrites of CA3 neurons. This increase was accounted for by BDNF exon 6 variant. In cultured hippocampal neurons, application of serotonin or norepinephrine (10-50 μM) induced increase in synaptic transmission and targeting of BDNF mRNA in dendrites. The increased expression of BDNF in CA3 dendrites following antidepressants or exercise further supports the neurotrophin hypothesis of antidepressants action and confirms that the differential subcellular localization of BDNF mRNA splice variants provides a spatial code for a selective expression of BDNF in specific subcellular districts. This selective expression may be exploited to design more specific antidepressants.

  20. Rotavirus activates lymphocytes from non-obese diabetic mice by triggering toll-like receptor 7 signaling and interferon production in plasmacytoid dendritic cells.

    Directory of Open Access Journals (Sweden)

    Jessica A Pane

    2014-03-01

    Full Text Available 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

  1. Cell-free culture supernatant of Bifidobacterium breve CNCM I-4035 decreases pro-inflammatory cytokines in human dendritic cells challenged with Salmonella typhi through TLR activation.

    Science.gov (United States)

    Bermudez-Brito, Miriam; Muñoz-Quezada, Sergio; Gomez-Llorente, Carolina; Matencio, Esther; Bernal, Maria J; Romero, Fernando; Gil, Angel

    2013-01-01

    Dendritic cells (DCs) constitute the first point of contact between gut commensals and our immune system. Despite growing evidence of the immunomodulatory effects of probiotics, the interactions between the cells of the intestinal immune system and bacteria remain largely unknown. Indeed,, the aim of this work was to determine whether the probiotic Bifidobacterium breve CNCM I-4035 and its cell-free culture supernatant (CFS) have immunomodulatory effects in human intestinal-like dendritic cells (DCs) and how they respond to the pathogenic bacterium Salmonella enterica serovar Typhi, and also to elucidate the molecular mechanisms involved in these interactions. Human DCs were directly challenged with B. breve/CFS, S. typhi or a combination of these stimuli for 4 h. The expression pattern of genes involved in Toll-like receptor (TLR) signaling pathway and cytokine secretion was analyzed. CFS decreased pro-inflammatory cytokines and chemokines in human intestinal DCs challenged with S. typhi. In contrast, the B. breve CNCM I-4035 probiotic strain was a potent inducer of the pro-inflammatory cytokines and chemokines tested, i.e., TNF-α, IL-8 and RANTES, as well as anti-inflammatory cytokines including IL-10. CFS restored TGF-β levels in the presence of Salmonella. Live B.breve and its supernatant enhanced innate immune responses by the activation of TLR signaling pathway. These treatments upregulated TLR9 gene transcription. In addition, CFS was a more potent inducer of TLR9 expression than the probiotic bacteria in the presence of S. typhi. Expression levels of CASP8 and IRAK4 were also increased by CFS, and both treatments induced TOLLIP gene expression. Our results indicate that the probiotic strain B. breve CNCM I-4035 affects the intestinal immune response, whereas its supernatant exerts anti-inflammatory effects mediated by DCs. This supernatant may protect immune system from highly infectious agents such as Salmonella typhi and can down-regulate pro

  2. TRIF is a critical negative regulator of TLR agonist mediated activation of dendritic cells in vivo.

    Directory of Open Access Journals (Sweden)

    Sergey S Seregin

    Full Text Available Despite recent advances in developing and licensing adjuvants, there is a great need for more potent formulations to enhance immunogenicity of vaccines. An Eimeria tenella derived antigen (rEA augments immune responses against several pathogens in animal models and recently was confirmed to be safe for human use. In this study, we have analyzed the molecular mechanisms underlying rEA activity in mice, and confirmed that rEA activates multiple immune cell types, including DCs, macrophages, NK, B, and T cells. The rEA adjuvant also elicits the induction of pleiotropic pro-inflammatory cytokines, responses that completely depend upon the presence of the TLR adaptor protein MyD88. Surprisingly, we also found that the TRIF adaptor protein acts as a potent negative regulator of TLR agonist-triggered immune responses. For example, IL12 production and the induction of co-stimulatory molecule expression by DCs and IFNγ production by NK cells in vivo were significantly increased in rEA-treated TRIF-KO mice. Importantly, however, TRIF suppressive effects were not restricted to rEA-mediated responses, but were apparent in LPS- or ODN2006-activated DCs as well. Taken together, our findings confirm that rEA is a potent adjuvant, triggering robust activation of the innate immune system, in a manner that is augmented by MyD88 and inhibited by TRIF; thereby unveiling the potential complexities of modulating TLR activity to augment vaccine efficacy.

  3. A Facile Method for Synthesizing Dendritic Core–Shell Structured Ternary Metallic Aerogels and Their Enhanced Electrochemical Performances

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Qiurong; Zhu, Chengzhou; Li, Yijing; Xia, Haibing; Engelhard, Mark H.; Fu, Shaofang; Du, Dan; Lin, Yuehe

    2016-11-08

    Currently, three dimensional self-supported metallic structures are attractive for their unique properties of high porosity, low density, excellent conductivity etc. that promote their wide application in fuel cells. Here, for the first time, we report a facile synthesis of dendritic core-shell structured Au/Pt3Pd ternary metallic aerogels via a one-pot self-assembly gelation strategy. The as-prepared Au/Pt3Pd ternary metallic aerogels demonstrated superior electrochemical performances toward oxygen reduction reaction compared to commercial Pt/C. The unique dendritic core-shell structures, Pt3Pd alloyed shells and the cross-linked network structures are beneficial for the electrochemical oxygen reduction reaction performances of the Pt-based materials via the electronic effect, geometric effect and synergistic effect. This strategy of fabrication of metallic hydrogels and aerogels as well as their exceptional properties hold great promise in a variety of applications.

  4. Activation of naïve NK cells in response to Listeria monocytogenes requires IL-18 and contact with infected dendritic cells1

    OpenAIRE

    Humann, Jessica; Lenz, Laurel L.

    2010-01-01

    The mechanisms for NK cell activation during infection by intracellular bacterial pathogens are not clearly defined. To dissect how Listeria monocytogenes infection elicits NK cell activation, we evaluated the requirements for activation of naïve splenic NK cells by infected bone marrow-derived dendritic cells (BMDC). We found that NK cell activation in this setting required infection of BMDC by live wild-type bacteria. NK cells were not activated when BMDC were infected with a live hemolysin...

  5. Conditional overexpression of insulin-like growth factor-1 enhances hippocampal neurogenesis and restores immature neuron dendritic processes after traumatic brain injury.

    Science.gov (United States)

    Carlson, Shaun W; Madathil, Sindhu K; Sama, Diana M; Gao, Xiang; Chen, Jinhui; Saatman, Kathryn E

    2014-08-01

    Traumatic brain injury (TBI) is associated with neuronal damage or neuronal death in the hippocampus, a region critical for cognitive function. Immature neurons within the hippocampal neurogenic niche are particularly susceptible to TBI. Therapeutic strategies that protect immature hippocampal neurons or enhance posttraumatic neurogenesis may be advantageous for promoting functional recovery after TBI. Insulin-like growth factor-1 (IGF-1) promotes neurogenesis in the adult brain, but its effects on neurogenesis after TBI are unknown. We used an astrocyte-specific conditional IGF-1-overexpressing mouse model to supplement IGF-1 in regions of neuronal damage and reactive astrocytosis after controlled cortical impact injury. Although early loss of immature neurons was not significantly attenuated, overexpression of IGF-1 resulted in a marked increase in immature neuron density in the subgranular zone at 10 days after injury. This delayed increase seemed to be driven by enhanced neuron differentiation rather than by increased cellular proliferation. In wild-type mice, dendrites of immature neurons exhibited significant decreases in total length and number of bifurcations at 10 days after injury versus neurons in sham-injured mice. In contrast, the morphology of immature neuron dendrites in brain-injured IGF-1-overexpressing mice was equivalent to that in sham controls. These data provide compelling evidence that IGF-1 promotes neurogenesis after TBI.

  6. Activation of Toll-like Receptor-2 by Endogenous Matrix Metalloproteinase-2 Modulates Dendritic-Cell-Mediated Inflammatory Responses

    Directory of Open Access Journals (Sweden)

    Emmanuelle Godefroy

    2014-12-01

    Full Text Available Matrix metalloproteinase-2 (MMP-2 is involved in several physiological mechanisms, including wound healing and tumor progression. We show that MMP-2 directly stimulates dendritic cells (DCs to both upregulate OX40L on the cell surface and secrete inflammatory cytokines. The mechanism underlying DC activation includes physical association with Toll-like receptor-2 (TLR2, leading to NF-κB activation, OX40L upregulation on DCs, and ensuing TH2 differentiation. Significantly, MMP-2 polarizes T cells toward type 2 responses in vivo, in a TLR2-dependent manner. MMP-2-dependent type 2 polarization may represent a key immune regulatory mechanism for protection against a broad array of disorders, such as inflammatory, infectious, and autoimmune diseases, which can be hijacked by tumors to evade immunity.

  7. Activation of Toll-like receptor-2 by endogenous matrix metalloproteinase-2 modulates dendritic cell-mediated inflammatory responses

    Science.gov (United States)

    Godefroy, Emmanuelle; Gallois, Anne; Idoyaga, Juliana; Merad, Miriam; Tung, Navpreet; Monu, Ngozi; Saenger, Yvonne; Fu, Yichun; Nair, Rajesh; Pulendran, Bali; Jotereau, Francine; Trombetta, Sergio; Bhardwaj, Nina

    2015-01-01

    SUMMARY Matrix metalloproteinase-2 (MMP-2) is involved in several physiological mechanisms, including wound healing and tumor progression. We show that MMP-2 directly stimulates dendritic cells (DCs) to both up-regulate OX40L on the cell surface and secrete inflammatory cytokines. The mechanism underlying DC activation includes physical association with Toll-like receptor-2 (TLR2), leading to NF-κB activation, OX40L up-regulation on DCs and ensuing TH2 differentiation. Significantly, MMP-2 polarizes T cells towards type-2 responses in vivo, in a TLR2-dependent manner. MMP-2-dependent type-2 polarization may represent a key immune regulatory mechanism to protect against a broad array of disorders, such as inflammatory, infectious and autoimmune diseases, which can be hijacked by tumors to evade immunity. PMID:25466255

  8. Activation of toll-like receptor-2 by endogenous matrix metalloproteinase-2 modulates dendritic-cell-mediated inflammatory responses.

    Science.gov (United States)

    Godefroy, Emmanuelle; Gallois, Anne; Idoyaga, Juliana; Merad, Miriam; Tung, Navpreet; Monu, Ngozi; Saenger, Yvonne; Fu, Yichun; Ravindran, Rajesh; Pulendran, Bali; Jotereau, Francine; Trombetta, Sergio; Bhardwaj, Nina

    2014-12-11

    Matrix metalloproteinase-2 (MMP-2) is involved in several physiological mechanisms, including wound healing and tumor progression. We show that MMP-2 directly stimulates dendritic cells (DCs) to both upregulate OX40L on the cell surface and secrete inflammatory cytokines. The mechanism underlying DC activation includes physical association with Toll-like receptor-2 (TLR2), leading to NF-κB activation, OX40L upregulation on DCs, and ensuing TH2 differentiation. Significantly, MMP-2 polarizes T cells toward type 2 responses in vivo, in a TLR2-dependent manner. MMP-2-dependent type 2 polarization may represent a key immune regulatory mechanism for protection against a broad array of disorders, such as inflammatory, infectious, and autoimmune diseases, which can be hijacked by tumors to evade immunity.

  9. Effects of dendritic cell vaccine activated with protein components of toxoplasma gondii on tumor specific CD8+ T-cells

    Directory of Open Access Journals (Sweden)

    Amari A

    2009-12-01

    Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} Background: Dendritic Cell (DC is an important antigen-presenting cell that present tumor antigen to CD8+ and CD4+ T- Lymphocytes and induce specific anti-tumor immunity. In order to induce effective anti-tumor response, an option is increasing the efficiency of antigen presentation of dendritic cells and T cell activation capacity. The aim of the present study was to investigate the effect of dendritic cell maturation with protein components of toxoplasma gondii on cytotoxic T lymphocyte activity and their infiltration in to the tumor."n"nMethods: For DC generation, bone marrow cells were cultured in the presence of GM-CSF and IL-4 for five days. After that, LPS, protein components and whole extract of toxoplasma gondii were added to the culture media and incubated for another two days for DC maturation. To generate tumor, mices were injected subcutaneously with WEHI-164 cell line. For immunotherapy 106 DCs matured with different compounds were injected around the tumor site. Infiltration of CD8+ T cells were determined by flow cytometry and cytotoxic activity was measured by LDH detection kit."n"nResults: Immunotherapy with DCs treated with protein components of toxoplasma gondii led to a significant increase in the

  10. Mouse bone marrow-derived dendritic cells can phagocytize the Sporothrix schenckii, and mature and activate the immune response by secreting interleukin-12 and presenting antigens to T lymphocytes.

    Science.gov (United States)

    Kusuhara, Masahiro; Qian, Hua; Li, Xiaoguang; Tsuruta, Daisuke; Tsuchisaka, Atsunari; Ishii, Norito; Ohata, Chika; Furumura, Minao; Hashimoto, Takashi

    2014-05-01

    In sporotrichosis, dermal dendritic cells were considered to participate in induction of the immune responses against Sporothrix schenckii infection. However, it is still unclear whether and how dermal dendritic cells were involved in the progress. To clarify the pathogenic role of dermal dendritic cells (DC) in sporotrichosis, we examined the phagocytosis, maturation stages, cytokine production and antigen-presenting ability of mouse bone marrow-derived DC after stimulation with S. schenckii. By analysis of flow cytometry, electron microscope and confocal microscope, mouse bone marrow-derived DC were proved to be able to phagocytize the S. schenckii. The increased expression of CD40, CD80 and CD86 on the surface of S. schenckii-pulsed mouse bone marrow-derived DC was detected by flow cytometer, indicating that the S. schenckii-pulsed mouse bone marrow-derived DC underwent the maturation program. The secretory enhancement of interleukin (IL)-12, but not IL-4, was found in S. schenckii-pulsed mouse bone marrow-derived DC, suggesting the possible activation of T-helper 1 prone immune responses. Furthermore, S. schenckii-pulsed mouse bone marrow-derived DC were demonstrated to be capable of inducing the proliferation of T lymphocytes from BALB/c mice that were pre-sensitized with S. schenckii. Together, all the results implied that dermal DC may participate in the induction of immune responses against S. schenckii infection in sporotrichosis.

  11. Lack of galectin-3 increases Jagged1/Notch activation in bone marrow-derived dendritic cells and promotes dysregulation of T helper cell polarization.

    Science.gov (United States)

    Fermino, Marise L; Dylon, L Sebastian D; Cecílio, Nerry T; Santos, Sofia N; Toscano, Marta A; Dias-Baruffi, Marcelo; Roque-Barreira, Maria C; Rabinovich, Gabriel A; Bernardes, Emerson S

    2016-08-01

    Galectin-3, an endogenous glycan-binding protein, is abundantly expressed at sites of inflammation and immune cell activation. Although this lectin has been implicated in the control of T helper (Th) polarization, the mechanisms underlying this effect are not well understood. Here, we investigated the role of endogenous galectin-3 during the course of experimental Leishmania major infection using galectin-3-deficient (Lgals3(-/-)) mice in a BALB/c background and the involvement of Notch signaling pathway in this process. Lgals3(-/-) mice displayed an augmented, although mixed Th1/Th2 responses compared with wild-type (WT) mice. Concomitantly, lymph node and footpad lesion cells from infected Lgals3(-/-) mice showed enhanced levels of Notch signaling components (Notch-1, Jagged1, Jagged2 and Notch target gene Hes-1). Bone marrow-derived dendritic cells (BMDCs) from uninfected Lgals3(-/-) mice also displayed increased expression of the Notch ligands Delta-like-4 and Jagged1 and pro-inflammatory cytokines. In addition, activation of Notch signaling in BMDCs upon stimulation with Jagged1 was more pronounced in Lgals3(-/-) BMDCs compared to WT BMDCs; this condition resulted in increased production of IL-6 by Lgals3(-/-) BMDCs. Finally, addition of exogenous galectin-3 to Lgals3(-/-) BMDCs partially reverted the increased sensitivity to Jagged1 stimulation. Our results suggest that endogenous galectin-3 regulates Notch signaling activation in BMDCs and influences polarization of T helper responses, thus increasing susceptibility to L. major infection.

  12. Enzymatic nanoreactors for environmentally benign biotransformations. 1. Formation and catalytic activity of supramolecular complexes of laccase and linear-dendritic block copolymers.

    Science.gov (United States)

    Gitsov, Ivan; Hamzik, James; Ryan, Joseph; Simonyan, Arsen; Nakas, James P; Omori, Shigetoshi; Krastanov, Albert; Cohen, Tomer; Tanenbaum, Stuart W

    2008-03-01

    We describe the construction of enzymatic nanoreactors through noncovalent envelopment of a glycoprotein by amphiphilic linear-dendritic AB or ABA copolymers. The synthetic procedure is based on the regioselective adsorption of dendritic poly(benzyl ether)-block-linear poly(ethylene glycol)-block-dendritic poly(benzyl ether) or linear poly(ethylene oxide)-block-dendritic poly(benzyl ether) copolymers onto the oxidative enzyme laccase from Trametes versicolor in aqueous medium. The complexes formed have improved catalytic activity compared with the native enzyme (77-85 nkat/mL vs 60 nkat/mL, respectively) and are more stable at elevated temperatures up to 70 degrees C. Experiments with deglycosylated laccase confirm that the glycoside fragments in the native enzyme serve as the anchor sites for the linear-dendritic copolymers. The enzymatic nanoreactors are able to effectively oxidize series of substrates: phenolic compounds (syringaldazine) and hydrophobic polyaromatic hydrocarbons (anthracene and benzo[a]pyrene) under "green" chemistry conditions.

  13. IRAK-M expression limits dendritic cell activation and proinflammatory cytokine production in response to Helicobacter pylori.

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    Jessica Shiu

    Full Text Available Helicobacter pylori (H. pylori infects the gastric mucosa and persists for the life of the host. Bacterial persistence may be due to the induction of regulatory T cells (Tregs whichmay have protective effects against other diseases such as asthma. It has been shown that H. pylori modulates the T cell response through dendritic cell reprogramming but the molecular pathways involved are relatively unknown. The goal of this study was to identify critical elements of dendritic cell (DC activation and evaluate potential influence on immune activation. Microarray analysis was used to demonstrate limited gene expression changes in H. pylori stimulated bone marrow derived DCs (BMDCs compared to the BMDCs stimulated with E. coli. IRAK-M, a negative regulator of TLR signaling, was upregulated and we selectedit for investigation of its role in modulating the DC and T cell responses. IRAK-M(-/- and wild type BMDC were compared for their response to H. pylori. Cells lacking IRAK-M produced significantly greater amounts of proinflammatory MIP-2 and reduced amounts of immunomodulatory IL-10 than wild type BMDC. IRAK-M(-/- cells also demonstrated increased MHC II expression upon activation. However, IRAK-M(-/- BMDCs were comparable to wild type BMDCs in inducing T-helper 17 (TH17 and Treg responses as demonstrated in vitro using BMDC CD4+ T cells co-culture assays,and in vivo though the adoptive transfer of CD4(+ FoxP3-GFP T cells into H. pylori infected IRAK-M(-/- mice. These results suggest that H. pylori infection leads to the upregulation of anti-inflammatory molecules like IRAK-M and that IRAK-M has a direct impact on innate functions in DCs such as cytokine and costimulation molecule upregulation but may not affect T cell skewing.

  14. Bordetella adenylate cyclase toxin differentially modulates toll-like receptor-stimulated activation, migration and T cell stimulatory capacity of dendritic cells.

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    Irena Adkins

    Full Text Available Adenylate cyclase toxin (CyaA is a key virulence factor of the whooping cough agent Bordetella pertussis. The toxin targets CD11b-expressing phagocytes and delivers into their cytosol an adenylyl cyclase (AC enzyme that subverts cellular signaling by increasing cAMP levels. In the present study, we analyzed the modulatory effects of CyaA on adhesive, migratory and antigen presenting properties of Toll-like receptor (TLR-activated murine and human dendritic cells (DCs. cAMP signaling of CyaA enhanced TLR-induced dissolution of cell adhesive contacts and migration of DCs towards the lymph node-homing chemokines CCL19 and CCL21 in vitro. Moreover, we examined in detail the capacity of toxin-treated DCs to induce CD4(+ and CD8(+ T cell responses. Exposure to CyaA decreased the capacity of LPS-stimulated DCs to present soluble protein antigen to CD4+ T cells independently of modulation of co-stimulatory molecules and cytokine production, and enhanced their capacity to promote CD4(+CD25(+Foxp3(+ T regulatory cells in vitro. In addition, CyaA decreased the capacity of LPS-stimulated DCs to induce CD8(+ T cell proliferation and limited the induction of IFN-γ producing CD8(+ T cells while enhancing IL-10 and IL-17-production. These results indicate that through activation of cAMP signaling, the CyaA may be mobilizing DCs impaired in T cell stimulatory capacity and arrival of such DCs into draining lymph nodes may than contribute to delay and subversion of host immune responses during B. pertussis infection.

  15. Clinical adjuvant combinations stimulate potent B-cell responses in vitro by activating dermal dendritic cells.

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    Katie Matthews

    Full Text Available CD14(+ dermal DCs (CD14(+ DDCs have a natural capacity to activate naïve B-cells. Targeting CD14(+ DDCs is therefore a rational approach for vaccination strategies aimed at improving humoral responses towards poorly immunogenic antigens, for example, HIV-1 envelope glycoproteins (Env. Here, we show that two clinically relevant TLR ligand combinations, Hiltonol plus Resiquimod and Glucopyranosyl lipid A plus Resiquimod, potently activate CD14(+ DDCs, as shown by enhanced expression of multiple cytokines (IL-6, IL-10, IL-12p40 and TNF-α. Furthermore, the responses of CD14(+ DDCs to these TLR ligands were not compromised by the presence of HIV-1 gp120, which can drive immunosuppressive effects in vitro and in vivo. The above TLR ligand pairs were better than the individual agents at boosting the inherent capacity of CD14(+ DDCs to induce naïve B-cells to proliferate and differentiate into CD27(+ CD38(+ B-cells that secrete high levels of immunoglobulins. CD14(+ DDCs stimulated by these TLR ligand combinations also promoted the differentiation of Th1 (IFN-γ-secreting, but not Th17, CD4(+ T-cells. These observations may help to identify adjuvant strategies aimed at inducing better antibody responses to vaccine antigens, including, but not limited to HIV-1 Env.

  16. The dendritic cell subtype-restricted C-type lectin Clec9A is a target for vaccine enhancement

    OpenAIRE

    Caminschi, Irina; Proietto, Anna I.; Ahmet, Fatma; Kitsoulis, Susie; Shin Teh, Joo; Lo, Jennifer C. Y.; Rizzitelli, Alexandra; Wu, Li; Vremec, David; van Dommelen, Serani L.H.; Campbell, Ian K.; Maraskovsky, Eugene; Braley, Hal; Davey, Gayle M.; Mottram, Patricia

    2008-01-01

    A novel dendritic cell (DC)–restricted molecule, Clec9A, was identified by gene expression profiling of mouse DC subtypes. Based on sequence similarity, a human ortholog was identified. Clec9A encodes a type II membrane protein with a single extracellular C-type lectin domain. Both the mouse Clec9A and human CLEC9A were cloned and expressed, and monoclonal antibodies (mAbs) against each were generated. Surface staining revealed that Clec9A was selective for mouse DCs and was restricted to the...

  17. A mucin-like peptide from Fasciola hepatica instructs dendritic cells with parasite specific Th1-polarizing activity.

    Science.gov (United States)

    Noya, Verónica; Brossard, Natalie; Rodríguez, Ernesto; Dergan-Dylon, L Sebastián; Carmona, Carlos; Rabinovich, Gabriel A; Freire, Teresa

    2017-01-12

    Fasciolosis is a trematode zoonosis of interest in public health and cattle production. We report here the immunostimulatory effect of a 66 mer mucin-like peptide from Fasciola hepatica (Fhmuc), which synergizes with lipopolysaccharide (LPS) to promote dendritic cell (DC) maturation, endowing these cells with Th1-polarizing capacity. Exposure of DCs to Fhmuc in presence of LPS induced enhanced secretion of pro-inflammatory cytokines and expression of co-stimulatory molecules by DCs, promoting their T cell stimulatory capacity and selectively augmenting IFN-γ secretion by allogeneic T cells. Furthermore, exposure of DCs to Fhmuc augmented LPS-induced Toll-like receptor (TLR) 4 expression on the cell surface. Finally, Fhmuc-conditioned DCs induced parasite specific-adaptive immunity with increased levels of IFN-γ secreted by splenocytes from vaccinated animals, and higher parasite-specific IgG antibodies. However, Fhmuc-treated DC conferred modest protection against F. hepatica infection highlighting the potent immuno-regulatory capacity of the parasite. In summary, this work highlights the capacity of a mucin-derived peptide from F. hepatica to enhance LPS-maturation of DCs and induce parasite-specific immune responses with potential implications in vaccination and therapeutic strategies.

  18. A mucin-like peptide from Fasciola hepatica instructs dendritic cells with parasite specific Th1-polarizing activity

    Science.gov (United States)

    Noya, Verónica; Brossard, Natalie; Rodríguez, Ernesto; Dergan-Dylon, L. Sebastián; Carmona, Carlos; Rabinovich, Gabriel A.; Freire, Teresa

    2017-01-01

    Fasciolosis is a trematode zoonosis of interest in public health and cattle production. We report here the immunostimulatory effect of a 66 mer mucin-like peptide from Fasciola hepatica (Fhmuc), which synergizes with lipopolysaccharide (LPS) to promote dendritic cell (DC) maturation, endowing these cells with Th1-polarizing capacity. Exposure of DCs to Fhmuc in presence of LPS induced enhanced secretion of pro-inflammatory cytokines and expression of co-stimulatory molecules by DCs, promoting their T cell stimulatory capacity and selectively augmenting IFN-γ secretion by allogeneic T cells. Furthermore, exposure of DCs to Fhmuc augmented LPS-induced Toll-like receptor (TLR) 4 expression on the cell surface. Finally, Fhmuc-conditioned DCs induced parasite specific-adaptive immunity with increased levels of IFN-γ secreted by splenocytes from vaccinated animals, and higher parasite-specific IgG antibodies. However, Fhmuc-treated DC conferred modest protection against F. hepatica infection highlighting the potent immuno-regulatory capacity of the parasite. In summary, this work highlights the capacity of a mucin-derived peptide from F. hepatica to enhance LPS-maturation of DCs and induce parasite-specific immune responses with potential implications in vaccination and therapeutic strategies. PMID:28079156

  19. Myosin II ATPase activity mediates the long-term potentiation-induced exodus of stable F-actin bound by drebrin A from dendritic spines.

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    Toshiyuki Mizui

    Full Text Available The neuronal actin-binding protein drebrin A forms a stable structure with F-actin in dendritic spines. NMDA receptor activation causes an exodus of F-actin bound by drebrin A (DA-actin from dendritic spines, suggesting a pivotal role for DA-actin exodus in synaptic plasticity. We quantitatively assessed the extent of DA-actin localization to spines using the spine-dendrite ratio of drebrin A in cultured hippocampal neurons, and found that (1 chemical long-term potentiation (LTP stimulation induces rapid DA-actin exodus and subsequent DA-actin re-entry in dendritic spines, (2 Ca(2+ influx through NMDA receptors regulates the exodus and the basal accumulation of DA-actin, and (3 the DA-actin exodus is blocked by myosin II ATPase inhibitor, but is not blocked by myosin light chain kinase (MLCK or Rho-associated kinase (ROCK inhibitors. These results indicate that myosin II mediates the interaction between NMDA receptor activation and DA-actin exodus in LTP induction. Furthermore, myosin II seems to be activated by a rapid actin-linked mechanism rather than slow MLC phosphorylation. Thus the myosin-II mediated DA-actin exodus might be an initial event in LTP induction, triggering actin polymerization and spine enlargement.

  20. Myosin II ATPase activity mediates the long-term potentiation-induced exodus of stable F-actin bound by drebrin A from dendritic spines.

    Science.gov (United States)

    Mizui, Toshiyuki; Sekino, Yuko; Yamazaki, Hiroyuki; Ishizuka, Yuta; Takahashi, Hideto; Kojima, Nobuhiko; Kojima, Masami; Shirao, Tomoaki

    2014-01-01

    The neuronal actin-binding protein drebrin A forms a stable structure with F-actin in dendritic spines. NMDA receptor activation causes an exodus of F-actin bound by drebrin A (DA-actin) from dendritic spines, suggesting a pivotal role for DA-actin exodus in synaptic plasticity. We quantitatively assessed the extent of DA-actin localization to spines using the spine-dendrite ratio of drebrin A in cultured hippocampal neurons, and found that (1) chemical long-term potentiation (LTP) stimulation induces rapid DA-actin exodus and subsequent DA-actin re-entry in dendritic spines, (2) Ca(2+) influx through NMDA receptors regulates the exodus and the basal accumulation of DA-actin, and (3) the DA-actin exodus is blocked by myosin II ATPase inhibitor, but is not blocked by myosin light chain kinase (MLCK) or Rho-associated kinase (ROCK) inhibitors. These results indicate that myosin II mediates the interaction between NMDA receptor activation and DA-actin exodus in LTP induction. Furthermore, myosin II seems to be activated by a rapid actin-linked mechanism rather than slow MLC phosphorylation. Thus the myosin-II mediated DA-actin exodus might be an initial event in LTP induction, triggering actin polymerization and spine enlargement.

  1. Lentivirally engineered dendritic cells activate AFP-specific T cells which inhibit hepatocellular carcinoma growth in vitro and in vivo.

    Science.gov (United States)

    Liu, Yang; Butterfield, Lisa H; Fu, Xiaohui; Song, Zhenshun; Zhang, Xiaoping; Lu, Chongde; Ding, Guanghui; Wu, Mengchao

    2011-07-01

    α-fetoprotein (AFP), a tumor-associated antigen for hepatocellular carcinoma (HCC), is an established biomarker for HCC. In this study, we created a lentivirus expressing the AFP antigen and investigated the anti-tumor activity of AFP-specific CD8+ T cells, with and without CD4+ T cells, which were activated by either AFP peptide-pulsed or Lenti-AFP-engineered Dendritic cells (DCs) in vitro and in vivo. AFP-specific T cells could efficiently kill HepG2 HCC cells, and produced IL-2, IFN-γ, TNF-α, perforin and granzyme B, with minimal production of IL-10 (a negative regulator of T cell activation). Both strategies activated AFP-specific T cells, but the lentiviral strategy was superior by several measures. Data also support an impact of CD4+ T cells in supporting anti-tumor activity. In vivo studies in a xenograft HCC tumor model also showed that AFP-specific T cells could markedly suppress HCC tumor formation and morbidity in tumor-bearing nude mice, as well as regulate serum levels of related cytokines and anti-tumor molecules. In parallel with human in vitro T cell cultures, the in vivo model demonstrated superior anti-tumor effects and Th1-skewing with Lenti-AFP-DCs. This study supports the superiority of a full-length antigen lentivirus-based DCs vaccine strategy over peptides, and provides new insight into the design of DCs-based vaccines.

  2. Mature dendritic cells generated from patient-derived peripheral blood monocytes in one-step culture using streptococcal preparation OK-432 exert an enhanced antigen-presenting capacity.

    Science.gov (United States)

    Naito, Kei; Ueda, Yuji; Itoh, Tsuyoshi; Fuji, Nobuaki; Shimizu, Keiji; Yano, Yutaro; Yamamoto, Yoshiki; Imura, Kenichiro; Kohara, Junji; Iwamoto, Arihiro; Shiozaki, Atsushi; Tamai, Hidemasa; Shimizu, Takeshi; Mazda, Osam; Yamagishi, Hisakazu

    2006-06-01

    Dendritic cells (DCs) have been shown to be potent in inducing cytotoxic T cell (CTL) response leading to the efficient anti-tumor effect in active immunotherapy. Myeloid DCs are conventionally generated from human peripheral blood monocytes in the presence of interleukin (IL)-4 and granulocyte/macrophage colony-stimulating factor (GM-CSF). Streptococcal preparation OK-432, which is known to be a multiple cytokine inducer, has been extensively studied as to its maturation effects on immature DCs using an in vitro culture system. The purpose of this study was to examine whether it could be possible to generate mature DCs directly from peripheral monocytes using OK-432. We specifically focused on the possibility that recombinant cytokines, which are considered to be essential for in vitro DC generation, could be substituted by OK-432. Human peripheral monocytes, which were obtained from patients with advanced cancer, were cultured with IL-4 and OK-432 for 7 days. Cultured cells were compared with DCs generated in the presence of IL-4 and GM-CSF with or without OK-432 with regard to the surface phenotype as well as the antigen-presenting capacity. As a result, the culture of monocytes in the presence of IL-4 followed by the addition of OK-432 on day 4 (IL-4/OK-DC) induced cells with a fully mature DC phenotype. Functional assays also demonstrated that IL-4/OK-DCs had a strong antigen-presenting capacity determined by their enhanced antigen-specific CTL response and exerted a Th1-type T cell response which is critical for the induction of anti-tumor response. In conclusion, human peripheral blood monocytes cultured in the presence of IL-4 and OK-432 without exogenous GM-CSF demonstrated a fully mature DC phenotype and strong antigen-presenting capacity. This one-step culture protocol allows us to generate fully mature DCs directly from monocytes in 7 days and thus, this protocol can be applicable for DC-based anti-tumor immunotherapy.

  3. Clinical grade OK432-activated dendritic cells: in vitro characterization and tracking during intralymphatic delivery.

    Science.gov (United States)

    West, Emma; Morgan, Ruth; Scott, Karen; Merrick, Alison; Lubenko, Anatole; Pawson, David; Selby, Peter; Hatfield, Paul; Prestwich, Robin; Fraser, Sheila; Eves, David; Anthoney, Alan; Twelves, Chris; Beirne, Debbie; Patel, Poulam; O'Donnell, Dearbhaile; Watt, Suzanne; Waller, Michael; Dietz, Allan; Robinson, Philip; Melcher, Alan

    2009-01-01

    Dendritic cells (DC) are under intense preclinical and early clinical evaluation for the immunotherapy of cancer. However, the optimal culture conditions and route of delivery for DC vaccination have not been established. Here we describe the first human application of DC matured with the bacterial agent OK432 (OK-DC), using a short-term serum-free culture protocol, which generates mature DC from CD14+ precursors after 5 days. These cells were prepared within the framework of a National Blood Service facility, demonstrating that DC represent a product which is potentially deliverable alongside current standardized cell therapies within the UK National Health Service. In vitro analysis confirmed that OK-DC were mature, secreted tumor necrosis factor-alpha, interleukin-6, and interleukin-12, and stimulated both T cell and natural killer cell function. To explore effective delivery of OK-DC to lymph nodes, we performed an initial clinical tracking study of radioactively labeled, unpulsed OK-DC after intralymphatic injection into the dorsum of the foot. We showed that injected DC rapidly localized to ipsilateral pelvic lymph nodes, but did not disseminate to more distant nodes over a 48-hour period. There was no significant toxicity associated with OK-DC delivery. These results show that OK-DC are suitable for clinical use, and that intralymphatic delivery is feasible for localizing cells to sites where optimal priming of innate and adaptive antitumor immunity is likely to occur.

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

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    Veronica Rainone

    Full Text Available 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.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 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.Data herein could be useful in the design of antitumoral DC-based therapies, showing a specific activation of immune system against breast cancer.

  5. Transcranial magnetic stimulation (TMS) inhibits cortical dendrites.

    Science.gov (United States)

    Murphy, Sean C; Palmer, Lucy M; Nyffeler, Thomas; Müri, René M; Larkum, Matthew E

    2016-03-18

    One of the leading approaches to non-invasively treat a variety of brain disorders is transcranial magnetic stimulation (TMS). However, despite its clinical prevalence, very little is known about the action of TMS at the cellular level let alone what effect it might have at the subcellular level (e.g. dendrites). Here, we examine the effect of single-pulse TMS on dendritic activity in layer 5 pyramidal neurons of the somatosensory cortex using an optical fiber imaging approach. We find that TMS causes GABAB-mediated inhibition of sensory-evoked dendritic Ca(2+) activity. We conclude that TMS directly activates fibers within the upper cortical layers that leads to the activation of dendrite-targeting inhibitory neurons which in turn suppress dendritic Ca(2+) activity. This result implies a specificity of TMS at the dendritic level that could in principle be exploited for investigating these structures non-invasively.

  6. The Attenuated Brucella abortus Strain 19 Invades, Persists in, and Activates Human Dendritic Cells, and Induces the Secretion of IL-12p70 but Not IL-23

    Science.gov (United States)

    Weinhold, Mario; Eisenblätter, Martin; Jasny, Edith; Fehlings, Michael; Finke, Antje; Gayum, Hermine; Rüschendorf, Ursula; Renner Viveros, Pablo; Moos, Verena; Allers, Kristina; Schneider, Thomas; Schaible, Ulrich E.; Schumann, Ralf R.; Mielke, Martin E.; Ignatius, Ralf

    2013-01-01

    Background Bacterial vectors have been proposed as novel vaccine strategies to induce strong cellular immunity. Attenuated strains of Brucella abortus comprise promising vector candidates since they have the potential to induce strong CD4+ and CD8+ T-cell mediated immune responses in the absence of excessive inflammation as observed with other Gram-negative bacteria. However, some Brucella strains interfere with the maturation of dendritic cells (DCs), which is essential for antigen-specific T-cell priming. In the present study, we investigated the interaction of human monocyte-derived DCs with the smooth attenuated B. abortus strain (S) 19, which has previously been employed successfully to vaccinate cattle. Methodology/Principal findings We first looked into the potential of S19 to hamper the cytokine-induced maturation of DCs; however, infected cells expressed CD25, CD40, CD80, and CD86 to a comparable extent as uninfected, cytokine-matured DCs. Furthermore, S19 activated DCs in the absence of exogeneous stimuli, enhanced the expression of HLA-ABC and HLA-DR, and was able to persist intracellularly without causing cytotoxicity. Thus, DCs provide a cellular niche for persisting brucellae in vivo as a permanent source of antigen. S19-infected DCs produced IL-12/23p40, IL-12p70, and IL-10, but not IL-23. While heat-killed bacteria also activated DCs, soluble mediators were not involved in S19-induced activation of human DCs. HEK 293 transfectants revealed cellular activation by S19 primarily through engagement of Toll-like receptor (TLR)2. Conclusions/Significance Thus, as an immunological prerequisite for vaccine efficacy, B. abortus S19 potently infects and potently activates (most likely via TLR2) human DCs to produce Th1-promoting cytokines. PMID:23805193

  7. The Attenuated Brucella abortus Strain 19 Invades, Persists in, and Activates Human Dendritic Cells, and Induces the Secretion of IL-12p70 but Not IL-23.

    Directory of Open Access Journals (Sweden)

    Mario Weinhold

    Full Text Available Bacterial vectors have been proposed as novel vaccine strategies to induce strong cellular immunity. Attenuated strains of Brucella abortus comprise promising vector candidates since they have the potential to induce strong CD4(+ and CD8(+ T-cell mediated immune responses in the absence of excessive inflammation as observed with other Gram-negative bacteria. However, some Brucella strains interfere with the maturation of dendritic cells (DCs, which is essential for antigen-specific T-cell priming. In the present study, we investigated the interaction of human monocyte-derived DCs with the smooth attenuated B. abortus strain (S 19, which has previously been employed successfully to vaccinate cattle.We first looked into the potential of S19 to hamper the cytokine-induced maturation of DCs; however, infected cells expressed CD25, CD40, CD80, and CD86 to a comparable extent as uninfected, cytokine-matured DCs. Furthermore, S19 activated DCs in the absence of exogeneous stimuli, enhanced the expression of HLA-ABC and HLA-DR, and was able to persist intracellularly without causing cytotoxicity. Thus, DCs provide a cellular niche for persisting brucellae in vivo as a permanent source of antigen. S19-infected DCs produced IL-12/23p40, IL-12p70, and IL-10, but not IL-23. While heat-killed bacteria also activated DCs, soluble mediators were not involved in S19-induced activation of human DCs. HEK 293 transfectants revealed cellular activation by S19 primarily through engagement of Toll-like receptor (TLR2.Thus, as an immunological prerequisite for vaccine efficacy, B. abortus S19 potently infects and potently activates (most likely via TLR2 human DCs to produce Th1-promoting cytokines.

  8. TLR4 and DC-SIGN receptors recognized Mycobacterium scrofulaceum promoting semi-activated phenotype on bone marrow dendritic cells.

    Science.gov (United States)

    Cruz-Aguilar, Marisa; Castillo-Rodal, Antonia I; Schcolnik-Cabrera, Alejandro; Bonifaz, Laura C; Molina, Gabriela; López-Vidal, Yolanda

    2016-07-01

    Nontuberculous mycobacteria (NTM) are recognized as emerging pathogens and their immune regulatory mechanisms are not well described yet. From them, Mycobacterium avium is known to be a weak activator of dendritic cells (DCs) that impairs the response induced by BCG vaccine. However, whether other NTM such as Mycobacterium scrofulaceum may modulate the activation of DCs, has not been extensively studied. Here, we exposed bone marrow-derived DCs (BMDCs) to M. scrofulaceum and we analyzed the effect on the activation of DCs. We found that M. scrofulaceum has a comparable ability to induce a semi-mature DC phenotype, which was produced by its interaction with DC-SIGN and TLR4 receptors in a synergic effect. BMDCs exposed to M. scrofulaceum showed high expression of PD-L2 and production of IL-10, as well as low levels of co-stimulatory molecules and pro-inflammatory cytokines. In addition to immunophenotype induced on DCs, changes in morphology, re-organization of cytoskeleton and decreased migratory capacity are consistent with a semi-mature phenotype. However, unlike other pathogenic mycobacteria, the DC-semi-mature phenotype induced by M. scrofulaceum was reversed after re-exposure to BCG, suggesting that modulation mechanisms of DC-activation used by M. scrofulaceum are different to other known pathogenic mycobacteria. This is the first report about the immunophenotypic characterization of DC stimulated by M. scrofulaceum.

  9. Dendritic transport element of human arc mRNA confers RNA degradation activity in a translation-dependent manner.

    Science.gov (United States)

    Ninomiya, Kensuke; Ohno, Mutsuhito; Kataoka, Naoyuki

    2016-11-01

    Localization of mRNA in neuronal cells is a critical process for spatiotemporal regulation of gene expression. Cytoplasmic localization of mRNA is often conferred by transport elements in 3' untranslated region (UTR). Activity-regulated cytoskeleton-associated protein (arc) mRNA is one of the localizing mRNAs in neuronal cells, and its localization is mediated by dendritic targeting element (DTE). As arc mRNA has introns in its 3' UTR, it was thought that arc mRNA is a natural target of nonsense-mediated mRNA decay (NMD). Here, we show that DTE in human arc 3' UTR has destabilizing activity of RNA independent of NMD pathway. DTE alone was able to cause instability of the reporter mRNA and this degradation was dependent on translation. Our results indicate that DTE has dual activity in mRNA transport and degradation, which suggests the novel spatiotemporal regulation mechanism of activity-dependent degradation of the mRNA.

  10. Hyperforin modulates dendritic spine morphology in hippocampal pyramidal neurons by activating Ca(2+) -permeable TRPC6 channels.

    Science.gov (United States)

    Leuner, Kristina; Li, Wei; Amaral, Michelle D; Rudolph, Stephanie; Calfa, Gaston; Schuwald, Anita M; Harteneck, Christian; Inoue, Takafumi; Pozzo-Miller, Lucas

    2013-01-01

    The standardized extract of the St. John's wort plant (Hypericum perforatum) is commonly used to treat mild to moderate depression. Its active constituent is hyperforin, a phloroglucinol derivative that reduces the reuptake of serotonin and norepinephrine by increasing intracellular Na(+) concentration through the activation of nonselective cationic TRPC6 channels. TRPC6 channels are also Ca(2+) -permeable, resulting in intracellular Ca(2+) elevations. Indeed, hyperforin activates TRPC6-mediated currents and Ca(2+) transients in rat PC12 cells, which induce their differentiation, mimicking the neurotrophic effect of nerve growth factor. Here, we show that hyperforin modulates dendritic spine morphology in CA1 and CA3 pyramidal neurons of hippocampal slice cultures through the activation of TRPC6 channels. Hyperforin also evoked intracellular Ca(2+) transients and depolarizing inward currents sensitive to the TRPC channel blocker La(3+) , thus resembling the actions of the neurotrophin brain-derived neurotrophic factor (BDNF) in hippocampal pyramidal neurons. These results suggest that the antidepressant actions of St. John's wort are mediated by a mechanism similar to that engaged by BDNF.

  11. Role of cell-to-cell variability in activating a positive feedback antiviral response in human dendritic cells.

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    Jianzhong Hu

    Full Text Available In the first few hours following Newcastle disease viral infection of human monocyte-derived dendritic cells, the induction of IFNB1 is extremely low and the secreted type I interferon response is below the limits of ELISA assay. However, many interferon-induced genes are activated at this time, for example DDX58 (RIGI, which in response to viral RNA induces IFNB1. We investigated whether the early induction of IFNBI in only a small percentage of infected cells leads to low level IFN secretion that then induces IFN-responsive genes in all cells. We developed an agent-based mathematical model to explore the IFNBI and DDX58 temporal dynamics. Simulations showed that a small number of early responder cells provide a mechanism for efficient and controlled activation of the DDX58-IFNBI positive feedback loop. The model predicted distributions of single cell responses that were confirmed by single cell mRNA measurements. The results suggest that large cell-to-cell variation plays an important role in the early innate immune response, and that the variability is essential for the efficient activation of the IFNB1 based feedback loop.

  12. Piezo Is Essential for Amiloride-Sensitive Stretch-Activated Mechanotransduction in Larval Drosophila Dorsal Bipolar Dendritic Sensory Neurons.

    Science.gov (United States)

    Suslak, Thomas J; Watson, Sonia; Thompson, Karen J; Shenton, Fiona C; Bewick, Guy S; Armstrong, J Douglas; Jarman, Andrew P

    2015-01-01

    Stretch-activated afferent neurons, such as those of mammalian muscle spindles, are essential for proprioception and motor co-ordination, but the underlying mechanisms of mechanotransduction are poorly understood. The dorsal bipolar dendritic (dbd) sensory neurons are putative stretch receptors in the Drosophila larval body wall. We have developed an in vivo protocol to obtain receptor potential recordings from intact dbd neurons in response to stretch. Receptor potential changes in dbd neurons in response to stretch showed a complex, dynamic profile with similar characteristics to those previously observed for mammalian muscle spindles. These profiles were reproduced by a general in silico model of stretch-activated neurons. This in silico model predicts an essential role for a mechanosensory cation channel (MSC) in all aspects of receptor potential generation. Using pharmacological and genetic techniques, we identified the mechanosensory channel, DmPiezo, in this functional role in dbd neurons, with TRPA1 playing a subsidiary role. We also show that rat muscle spindles exhibit a ruthenium red-sensitive current, but found no expression evidence to suggest that this corresponds to Piezo activity. In summary, we show that the dbd neuron is a stretch receptor and demonstrate that this neuron is a tractable model for investigating mechanisms of mechanotransduction.

  13. Method for enhancing amidohydrolase activity of fatty acid amide hydrolase

    Energy Technology Data Exchange (ETDEWEB)

    John, George; Nagarajan, Subbiah; Chapman, Kent; Faure, Lionel; Koulen, Peter

    2016-10-25

    A method for enhancing amidohydrolase activity of Fatty Acid Amide Hydrolase (FAAH) is disclosed. The method comprising administering a phenoxyacylethanolamide that causes the enhanced activity. The enhanced activity can have numerous effects on biological organisms including, for example, enhancing the growth of certain seedlings. The subject matter disclosed herein relates to enhancers of amidohydrolase activity.

  14. Modification of dendritic development.

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    Feria-Velasco, Alfredo; del Angel, Alma Rosa; Gonzalez-Burgos, Ignacio

    2002-01-01

    Since 1890 Ramón y Cajal strongly defended the theory that dendrites and their processes and spines had a function of not just nutrient transport to the cell body, but they had an important conductive role in neural impulse transmission. He extensively discussed and supported this theory in the Volume 1 of his extraordinary book Textura del Sistema Nervioso del Hombre y de los Vertebrados. Also, Don Santiago significantly contributed to a detailed description of the various neural components of the hippocampus and cerebral cortex during development. Extensive investigation has been done in the last Century related to the functional role of these complex brain regions, and their association with learning, memory and some limbic functions. Likewise, the organization and expression of neuropsychological qualities such as memory, exploratory behavior and spatial orientation, among others, depend on the integrity and adequate functional activity of the cerebral cortex and hippocampus. It is known that brain serotonin synthesis and release depend directly and proportionally on the availability of its precursor, tryptophan (TRY). By using a chronic TRY restriction model in rats, we studied their place learning ability in correlation with the dendritic spine density of pyramidal neurons in field CA1 of the hippocampus during postnatal development. We have also reported alterations in the maturation pattern of the ability for spontaneous alternation and task performance evaluating short-term memory, as well as adverse effects on the density of dendritic spines of hippocampal CA1 field pyramidal neurons and on the dendritic arborization and the number of dendritic spines of pyramidal neurons from the third layer of the prefrontal cortex using the same model of TRY restriction. The findings obtained in these studies employing a modified Golgi method, can be interpreted as a trans-synaptic plastic response due to understimulation of serotoninergic receptors located in the

  15. Impact of MAPK Pathway Activation in BRAF(V600) Melanoma on T Cell and Dendritic Cell Function.

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    Ott, Patrick A; Bhardwaj, Nina

    2013-10-28

    Constitutive upregulation of the MAPK pathway by a BRAF(V600) mutation occurs in about half of melanomas. This leads to increased oncogenic properties such as tumor cell invasion, metastatic potential, and resistance to apoptosis. Blockade of the MAPK pathway with highly specific kinase inhibitors induces unprecedented tumor response rates in patients with advanced BRAF(V600) mutant melanoma. Immune checkpoint blockade with monoclonal antibodies targeting cytotoxic T-lymphocyte antigen 4 and programed death-1/PD-L1 has also demonstrated striking anti-tumor activity in patients with advanced melanoma. Tumor responses are likely limited by multiple additional layers of immune suppression in the tumor microenvironment. There is emerging preclinical and clinical evidence suggesting that MAPK inhibition has a beneficial effect on the immunosuppressive tumor microenvironment, providing a strong rationale for combined immunotherapy and MAPK pathway inhibition in melanoma. The T cell response has been the main focus in the studies reported to date. Since dendritic cells (DCs) are important in the induction of tumor-specific T cell responses, the impact of MAPK pathway activation in melanoma on DC function is critical for the melanoma directed immune response. BRAF(V600E) melanoma cells modulate DCs through the MAPK pathway because its blockade in melanoma cells can reverse suppression of DC function. As both MEK/BRAF inhibition and immune checkpoint blockade have recently taken center stage in the treatment of melanoma, a deeper understanding of how MAPK pathway inhibition affects the tumor immune response is needed.

  16. 3-bromopyruvate ameliorate autoimmune arthritis by modulating Th17/Treg cell differentiation and suppressing dendritic cell activation.

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    Okano, Takaichi; Saegusa, Jun; Nishimura, Keisuke; Takahashi, Soshi; Sendo, Sho; Ueda, Yo; Morinobu, Akio

    2017-02-10

    Recent studies have shown that cellular metabolism plays an important role in regulating immune cell functions. In immune cell differentiation, both interleukin-17-producing T (Th17) cells and dendritic cells (DCs) exhibit increased glycolysis through the upregulation of glycolytic enzymes, such as hexokinase-2 (HK2). Blocking glycolysis with 2-deoxyglucose was recently shown to inhibit Th17 cell differentiation while promoting regulatory T (Treg) cell generation. However, 2-DG inhibits all isoforms of HK. Thus, it is unclear which isoform has a critical role in Th17 cell differentiation and in rheumatoid arthritis (RA) pathogenesis. Here we demonstrated that 3-bromopyruvate (BrPA), a specific HK2 inhibitor, significantly decreased the arthritis scores and the histological scores in SKG mice, with a significant increase in Treg cells, decrease in Th17 cells, and decrease in activated DCs in the spleen. In vitro, BrPA facilitated the differentiation of Treg cells, suppressed Th17 cells, and inhibited the activation of DCs. These results suggested that BrPA may be a therapeutic target of murine arthritis. Although the role of IL-17 is not clarified in the treatment of RA, targeting cell metabolism to alter the immune cell functions might lead to a new therapeutic strategy for RA.

  17. Enhancement of CA3 hippocampal network activity by activation of group II metabotropic glutamate receptors.

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    Ster, Jeanne; Mateos, José María; Grewe, Benjamin Friedrich; Coiret, Guyllaume; Corti, Corrado; Corsi, Mauro; Helmchen, Fritjof; Gerber, Urs

    2011-06-14

    Impaired function or expression of group II metabotropic glutamate receptors (mGluRIIs) is observed in brain disorders such as schizophrenia. This class of receptor is thought to modulate activity of neuronal circuits primarily by inhibiting neurotransmitter release. Here, we characterize a postsynaptic excitatory response mediated by somato-dendritic mGluRIIs in hippocampal CA3 pyramidal cells and in stratum oriens interneurons. The specific mGluRII agonists DCG-IV or LCCG-1 induced an inward current blocked by the mGluRII antagonist LY341495. Experiments with transgenic mice revealed a significant reduction of the inward current in mGluR3(-/-) but not in mGluR2(-/-) mice. The excitatory response was associated with periods of synchronized activity at theta frequency. Furthermore, cholinergically induced network oscillations exhibited decreased frequency when mGluRIIs were blocked. Thus, our data indicate that hippocampal responses are modulated not only by presynaptic mGluRIIs that reduce glutamate release but also by postsynaptic mGluRIIs that depolarize neurons and enhance CA3 network activity.

  18. Antitumor Activity and Immune Enhancement of Murine Interleukin-23 Expressed in Murine Colon Carcinoma Cells

    Institute of Scientific and Technical Information of China (English)

    Baoen Shan; Jingsheng Hao; Qiaoxia Li; Masatoshi Tagawa

    2006-01-01

    Interleukin (IL)-23, a cytokine composed of p19 and the p40 subunit of IL-12, can enhance the proliferation of memory T cells and production of IFN-γ from activated T cells. It can also induce antitumor effects in murine model. To further evaluate the antitumor activity and immune enhancement of IL-23 in vivo, murine colon carcinoma cells retrovirally transduced with mIL-23 gene were injected subcutaneously (s.c.) into BALB/c mice.Survival time and tumor volume were observed. LDH release assay, [3H]-TdR incorporation assay and ELISA were used to determine CTL activity, proliferation of splenocytes and level of cytokines, respectively. Number of dendritic cells (DCs) was analyzed by flow cytometry (FCM). IL-23 secreted by Colon26/IL-23 cells suppressed the growth of tumor and prolonged the survival time of mice, enhanced proliferation of splenocytes, CTL activity, and number of DCs. IL-23 also promoted the production of Th1 cytokines such as IFN-γ, IL-12 and TNF-o. However,the level of IL-4 was not enhanced significantly. These data suggested that IL-23 secreted by tumor cells can induce antitumor activity by enhancing immune response.

  19. Exosomes derived from dendritic cells improve cardiac function via activation of CD4(+) T lymphocytes after myocardial infarction.

    Science.gov (United States)

    Liu, Haibo; Gao, Wei; Yuan, Jie; Wu, Chaoneng; Yao, Kang; Zhang, Li; Ma, Leilei; Zhu, Jianbing; Zou, Yunzeng; Ge, Junbo

    2016-02-01

    CD4(+) T cell activation plays a key role in facilitating wound healing after myocardial infarction (MI). Exosomes (EXs) secreted from dendritic cells (DCs) can activate T cells in tumor models; however, whether DEXs (DC-EXs) can mediate CD4(+) T cell activation and improve wound healing post-MI remains unknown. This study sought to determine whether DEXs mediate CD4(+) T cell activation and improve cardiac function post-MI in mice. We used supernatants of hypoxic primary or necrotic HL-1 cardiomyocytes to simulate the post-MI cardiomyocyte microenvironment in vitro. Cultured bone marrow-derived DCs (BMDCs) from mice were stimulated with the supernatants of normal (Control group), hypoxic primary or necrotic HL-1 cardiomyocytes (MI group); a subset of BMDCs remained unstimulated (Negative group). DEXs were then isolated from the BMDC supernatants and either incubated with CD4(+) T cells or injected into mice via the tail vein. In this study, we found that the supernatants of both hypoxic primary and necrotic HL-1 cardiomyocytes upregulate DC maturation markers. After the injection of DEXs, a greater number of MI-DEXs are recruited by the mouse spleen and with greater rapidity than control- or negative-DEXs. Confocal imaging and flow cytometry revealed that MI-DEXs exhibited higher uptake by splenic CD4(+) T cells than the control- and negative-DEXs, and this increase was correlated with significantly greater increases in the expression of chemokines and the inflammatory cytokines IFN-γ and TNF by the CD4(+) T cells in vitro and in vivo. In addition, the injection of MI-DEXs improved cardiac function in mice post-MI. These results suggest that DEXs could mediate the activation of CD4(+) T cells through an endocrine mechanism and improve cardiac function post-MI. Our findings provide the basis for a novel strategy for the treatment of MI through the systemic delivery of DEXs.

  20. Dendritic cell editing by activated natural killer cells results in a more protective cancer-specific immune response.

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    Barbara Morandi

    Full Text Available Over the last decade, several studies have extensively reported that activated natural killer (NK cells can kill autologous immature dendritic cells (DCs in vitro, whereas they spare fully activated DCs. This led to the proposal that activated NK cells might select a more immunogenic subset of DCs during a protective immune response. However, there is no demonstration that autologous DC killing by NK cells is an event occurring in vivo and, consequently, the functional relevance of this killing remains elusive. Here we report that a significant decrease of CD11c(+ DCs was observed in draining lymph nodes of mice inoculated with MHC-devoid cells as NK cell targets able to induce NK cell activation. This in vivo DC editing by NK cells was perforin-dependent and it was functionally relevant, since residual lymph node DCs displayed an improved capability to induce T cell proliferation. In addition, in a model of anti-cancer vaccination, the administration of MHC-devoid cells together with tumor cells increased the number of tumor-specific CTLs and resulted in a significant increase in survival of mice upon challenge with a lethal dose of tumor cells. Depletion of NK cells or the use of perforin knockout mice strongly decreased the tumor-specific CTL expansion and its protective role against tumor cell challenge. As a whole, our data support the hypothesis that NK cell-mediated DC killing takes place in vivo and is able to promote expansion of cancer-specific CTLs. Our results also indicate that cancer vaccines could be improved by strategies aimed at activating NK cells.

  1. Silencing B7-H1 enhances the anti-tumor effect of bladder cancer antigen-loaded dendritic cell vaccine in vitro

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    Wang S

    2014-08-01

    Full Text Available Shuo Wang,1 Yonghua Wang,1 Jing Liu,2 Shixiu Shao,1 Xianjun Li,1 Jiannan Gao,1 Haitao Niu,1 Xinsheng Wang1 1Department of Urology, 2Department of Pediatrics, The Affiliated Hospital of Qingdao University, Qingdao, People's Republic of China Objective: The aim of this study was to examine whether short hairpin RNA (shRNA expressing lentiviral particles targeting B7-H1 infection could result in B7-H1 knockdown on dendritic cells (DCs and to investigate whether B7-H1 silencing could augment the immune function of DCs and further elicit a more potent anti-tumor immune effect against bladder cancer cells in vitro. Methods: Monocyte-derived DCs, which were generated from peripheral blood mononuclear cells, were infected by a recombinant lentivirus containing shRNA sequence aimed at B7-H1. After that, the infected DCs were pulsed by tumor antigens and used to stimulate cytotoxic T lymphocytes-based anti-tumor effect in vitro. Results: The lentivirus-mediated shRNA delivery method efficiently and effectively silenced B7-H1 in DCs. Furthermore, the B7-H1 silencing enhanced the stimulatory capacity and the secretion of interleukin-12, but down-regulated interleukin-10 secretion. And more importantly, the anti-tumor effect of bladder cancer antigen-loaded DC vaccine in vitro was also potentially augmented. Conclusion: This study suggests that a combination of B7-H1 knockdown and target antigen delivery could augment anti-tumor effects in vitro, which potentially provides a novel strategy in the immunotherapy of bladder cancer. Keywords: B7-H1, bladder cancer, dendritic cell, vaccine, immunotherapy

  2. Bone morphogenetic protein-5 (BMP-5 promotes dendritic growth in cultured sympathetic neurons

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    Higgins Dennis

    2001-09-01

    Full Text Available Abstract Background BMP-5 is expressed in the nervous system throughout development and into adulthood. However its effects on neural tissues are not well defined. BMP-5 is a member of the 60A subgroup of BMPs, other members of which have been shown to stimulate dendritic growth in central and peripheral neurons. We therefore examined the possibility that BMP-5 similarly enhances dendritic growth in cultured sympathetic neurons. Results Sympathetic neurons cultured in the absence of serum or glial cells do not form dendrites; however, addition of BMP-5 causes these neurons to extend multiple dendritic processes, which is preceded by an increase in phosphorylation of the Smad-1 transcription factor. The dendrite-promoting activity of BMP-5 is significantly inhibited by the BMP antagonists noggin and follistatin and by a BMPR-IA-Fc chimeric protein. RT-PCR and immunocytochemical analyses indicate that BMP-5 mRNA and protein are expressed in the superior cervical ganglia (SCG during times of initial growth and rapid expansion of the dendritic arbor. Conclusions These data suggest a role for BMP-5 in regulating dendritic growth in sympathetic neurons. The signaling pathway that mediates the dendrite-promoting activity of BMP-5 may involve binding to BMPR-IA and activation of Smad-1, and relative levels of BMP antagonists such as noggin and follistatin may modulate BMP-5 signaling. Since BMP-5 is expressed at relatively high levels not only in the developing but also the adult nervous system, these findings suggest the possibility that BMP-5 regulates dendritic morphology not only in the developing, but also the adult nervous system.

  3. IgE/FcεRI-Mediated Antigen Cross-Presentation by Dendritic Cells Enhances Anti-Tumor Immune Responses

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    Barbara Platzer

    2015-03-01

    Full Text Available Epidemiologic studies discovered an inverse association between immunoglobulin E (IgE-mediated allergies and cancer, implying tumor-protective properties of IgE. However, the underlying immunologic mechanisms remain poorly understood. Antigen cross-presentation by dendritic cells (DCs is of key importance for anti-tumor immunity because it induces the generation of cytotoxic CD8+ T lymphocytes (CTLs with specificity for tumor antigens. We demonstrate that DCs use IgE and FcεRI, the high-affinity IgE receptor, for cross-presentation and priming of CTLs in response to free soluble antigen at low doses. Importantly, IgE/FcεRI-mediated cross-presentation is a distinct receptor-mediated pathway because it does not require MyD88 signals or IL-12 induction in DCs. Using passive immunization with tumor antigen-specific IgE and DC-based vaccination experiments, we demonstrate that IgE-mediated cross-presentation significantly improves anti-tumor immunity and induces memory responses in vivo. Our findings suggest a cellular mechanism for the tumor-protective features of IgE and expand the known physiological functions of this immunoglobulin.

  4. Potassium conductances mediate bidirectional state-dependent modulation of action potential evoked dendritic calcium signals in dentate gyrus granule cells

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    János Brunner

    2014-03-01

    Full Text Available Backpropagating action potentials (bAPs and local calcium signals that they trigger are fundamental for dendritic functions. Here we addressed the question what extent the changes of local dendritic membrane properties can contribute to the shaping of the coupling between dendritic action potentials and the local calcium responses. Using a combination of in vitro electrophysiological and confocal imaging techniques we found that activation of dendritic GIRK channels via mGlu2 or GABAB receptors enhanced the bAP¬-triggered calcium signals in the dendrites of dentate gyrus granule cells (GCs. The enhancement of calcium signals was significant only in those dendritic regions, where these receptors are predominantly expressed. Similarly to GIRK channel activation, somatic hyperpolarization by DC current injection (from -64 mV to -77 mV, significantly increased bAP-associated calcium signals in the proximal dendrites. The hyperpolarization was associated with a decrease in the input resistance due to the rectification of the membrane potential of GCs. The effect of hyperpolarization on the calcium signals was maintained when T-type calcium currents were blocked but it decreased when GIRK channels were inhibited. Simultaneous dual somato-dendritic recordings from GCs showed that somatic hyperpolarization accelerated the repolarization phase of dendritic bAP in the proximal region whereas the rising phase and peak amplitude was not affected. We hypothesize that the larger driving force for calcium ions during the faster repolarization can contribute to the increasing in calcium signals. Employment of previously recorded dendritic bAP waveforms from hyperpolarized membrane potential as voltage command evoked larger calcium currents in nucleated patches compared to bAP waveform from the same recording at depolarized membrane potential. Furthermore, addition of native, high-voltage activated, inactivating potassium conductance by somatic dynamic clamp

  5. Dengue-2 and yellow fever 17DD viruses infect human dendritic cells, resulting in an induction of activation markers, cytokines and chemokines and secretion of different TNF-α and IFN-α profiles

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    Mariana Gandini

    2011-08-01

    Full Text Available Flaviviruses cause severe acute febrile and haemorrhagic infections, including dengue and yellow fever and the pathogenesis of these infections is caused by an exacerbated immune response. Dendritic cells (DCs are targets for dengue virus (DENV and yellow fever virus (YF replication and are the first cell population to interact with these viruses during a natural infection, which leads to an induction of protective immunity in humans. We studied the infectivity of DENV2 (strain 16681, a YF vaccine (YF17DD and a chimeric YF17D/DENV2 vaccine in monocyte-derived DCs in vitro with regard to cell maturation, activation and cytokine production. Higher viral antigen positive cell frequencies were observed for DENV2 when compared with both vaccine viruses. Flavivirus-infected cultures exhibited dendritic cell activation and maturation molecules. CD38 expression on DCs was enhanced for both DENV2 and YF17DD, whereas OX40L expression was decreased as compared to mock-stimulated cells, suggesting that a T helper 1 profile is favoured. Tumor necrosis factor (TNF-α production in cell cultures was significantly higher in DENV2-infected cultures than in cultures infected with YF17DD or YF17D/DENV. In contrast, the vaccines induced higher IFN-α levels than DENV2. The differential cytokine production indicates that DENV2 results in TNF induction, which discriminates it from vaccine viruses that preferentially stimulate interferon expression. These differential response profiles may influence the pathogenic infection outcome.

  6. Dengue-2 and yellow fever 17DD viruses infect human dendritic cells, resulting in an induction of activation markers, cytokines and chemokines and secretion of different TNF-α and IFN-α profiles.

    Science.gov (United States)

    Gandini, Mariana; Reis, Sonia Regina Nogueira Ignacio; Torrentes-Carvalho, Amanda; Azeredo, Elzinandes Leal; Freire, Marcos da Silva; Galler, Ricardo; Kubelka, Claire Fernandes

    2011-08-01

    Flaviviruses cause severe acute febrile and haemorrhagic infections, including dengue and yellow fever and the pathogenesis of these infections is caused by an exacerbated immune response. Dendritic cells (DCs) are targets for dengue virus (DENV) and yellow fever virus (YF) replication and are the first cell population to interact with these viruses during a natural infection, which leads to an induction of protective immunity in humans. We studied the infectivity of DENV2 (strain 16681), a YF vaccine (YF17DD) and a chimeric YF17D/DENV2 vaccine in monocyte-derived DCs in vitro with regard to cell maturation, activation and cytokine production. Higher viral antigen positive cell frequencies were observed for DENV2 when compared with both vaccine viruses. Flavivirus-infected cultures exhibited dendritic cell activation and maturation molecules. CD38 expression on DCs was enhanced for both DENV2 and YF17DD, whereas OX40L expression was decreased as compared to mock-stimulated cells, suggesting that a T helper 1 profile is favoured. Tumor necrosis factor (TNF)-α production in cell cultures was significantly higher in DENV2-infected cultures than in cultures infected with YF17DD or YF17D/DENV. In contrast, the vaccines induced higher IFN-α levels than DENV2. The differential cytokine production indicates that DENV2 results in TNF induction, which discriminates it from vaccine viruses that preferentially stimulate interferon expression. These differential response profiles may influence the pathogenic infection outcome.

  7. Stimulatory effect of Echinacea purpurea extract on the trafficking activity of mouse dendritic cells: revealed by genomic and proteomic analyses

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    Wang Bi-Xue

    2010-11-01

    Full Text Available Abstract Background Several Echinacea species have been used as nutraceuticals or botanical drugs for "immunostimulation", but scientific evidence supporting their therapeutic use is still controversial. In this study, a phytocompound mixture extracted from the butanol fraction (BF of a stem and leaf (S+L extract of E. purpurea ([BF/S+L/Ep] containing stringently defined bioactive phytocompounds was obtained using standardized and published procedures. The transcriptomic and proteomic effects of this phytoextract on mouse bone marrow-derived dendritic cells (BMDCs were analyzed using primary cultures. Results Treatment of BMDCs with [BF/S+L/Ep] did not significantly influence the phenotypic maturation activity of dendritic cells (DCs. Affymetrix DNA microarray and bioinformatics analyses of genes differentially expressed in DCs treated with [BF/S+L/Ep] for 4 or 12 h revealed that the majority of responsive genes were related to cell adhesion or motility (Cdh10, Itga6, Cdh1, Gja1 and Mmp8, or were chemokines (Cxcl2, Cxcl7 or signaling molecules (Nrxn1, Pkce and Acss1. TRANSPATH database analyses of gene expression and related signaling pathways in treated-DCs predicted the JNK, PP2C-α, AKT, ERK1/2 or MAPKAPK pathways as the putative targets of [BF/S+L/Ep]. In parallel, proteomic analysis showed that the expressions of metabolic-, cytoskeleton- or NF-κB signaling-related proteins were regulated by treatment with [BF/S+L/Ep]. In vitro flow cytometry analysis of chemotaxis-related receptors and in vivo cell trafficking assay further showed that DCs treated with [BF/S+L/Ep] were able to migrate more effectively to peripheral lymph node and spleen tissues than DCs treated as control groups. Conclusion Results from this study suggest that [BF/S+L/Ep] modulates DC mobility and related cellular physiology in the mouse immune system. Moreover, the signaling networks and molecules highlighted here are potential targets for nutritional or clinical

  8. The cystine/glutamate antiporter regulates indoleamine 2,3-dioxygenase protein levels and enzymatic activity in human dendritic cells.

    Science.gov (United States)

    Mattox, Mildred L; D'Angelo, June A; Grimes, Zachary M; Fiebiger, Edda; Dickinson, Bonny L

    2012-11-30

    Indoleamine 2,3-dioxygenase (IDO) is the rate-limiting enzyme in the tryptophan-catabolizing pathway and a key regulator of peripheral immune tolerance. As the suppressive effects of IDO are predominantly mediated by dendritic cells (DCs) and IDO-competent DCs promote long-term immunologic tolerance, a detailed understanding of how IDO expression and activity is regulated in these cells is central to the rational design of therapies to induce robust immune tolerance. We previously reported that the cystine/glutamate antiporter modulates the functional expression of IDO in human monocyte-derived DCs. Specifically, we showed that blocking antiporter uptake of cystine significantly increased both IDO mRNA and IDO enzymatic activity and that this correlated with impaired DC presentation of exogenous antigen to T cells via MHC class II and the cross-presentation pathway. The antiporter regulates intracellular and extracellular redox by transporting cystine into the cell in exchange for glutamate. Intracellular cystine is reduced to cysteine to support biosynthesis of the major cellular antioxidant glutathione and cysteine is exported from the cell where it functions as an extracellular antioxidant. Here we show that antiporter control of IDO expression in DCs is reversible, independent of interferon-γ, regulated by redox, and requires active protein synthesis. These findings highlight a role for antiporter regulation of cellular redox as a critical control point for modulating IDO expression and activity in DCs. Thus, systemic disease and aging, processes that perturb redox homeostasis, may adversely affect immunity by promoting the generation of IDO-competent DCs.

  9. Direct activation of human dendritic cells by particle-bound but not soluble MHC class II ligand.

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    Renato B Baleeiro

    Full Text Available Dendritic cells (DCs are key activators of cellular immune responses through their capacity to induce naïve T cells and sustained effector T cell responses. This capacity is a function of their superior efficiency of antigen presentation via MHC class I and class II molecules, and the expression of co-stimulatory cell surface molecules and cytokines. Maturation of DCs is induced by microbial factors via pattern recognition receptors such as Toll-like receptors, pro-inflammatory cytokines or cognate interaction with CD4(+ T cells. Here we show that, unexpectedly, the PanDR helper T cell epitope PADRE, a generic T helper cell antigen presented by a large fraction of HLA-DR alleles, when delivered in particle-bound form induced maturation of human DCs. The DCs that received the particle-bound PADRE displayed all features of fully mature DCs, such as high expression of the co-stimulatory molecules CD80, CD86, CD83, the MHC-II molecule HLA-DR, secretion of high levels of the biologically active IL-12 (IL-12p70 and induction of vigorous proliferation of naïve CD4(+ T cells. Furthermore, the maturation of DCs induced by particle-bound PADRE was shown to involve sphingosine kinase, calcium signaling from internal sources and downstream signaling through the MAP kinase and the p72syk pathways, and finally activation of the transcription factor NF-κB. Based on our findings, we propose that particle-bound PADRE may be used as a DC activator in DC-based vaccines.

  10. The active translation of MHCII mRNA during dendritic cells maturation supplies new molecules to the cell surface pool.

    Science.gov (United States)

    Malanga, Donatella; Barba, Pasquale; Harris, Paul E; Maffei, Antonella; Del Pozzo, Giovanna

    2007-04-01

    The transition of human dendritic cells (DCs) from the immature to the mature phenotype is characterized by an increased density of MHC class II (MHCII) molecules on the plasma membrane, a key requirement of their competence as professional antigen presenting cells (APCs). MHCII molecules on the cell surface derive from newly synthesized as well as from preexisting proteins. So far, all the studies done on DCs during maturation, to establish the relative contribution of newly synthesized MHCII molecules to the cell surface pool did not produced a clear, unified scenario. We report that, in human DCs stimulated ex vivo with LPS, the changes in the RNA accumulation specific for at least two MHCII genes (HLA-DRA and HLA-DQA1) due to transcriptional upregulation, is associated with the active translation at high rate of these transcripts. Our finding reveals that, across the 24h of the maturation process in human DCs, newly synthesized MHCII proteins are supplied to the APCs cell surface pool.

  11. Borrelia burgdorferi Induces TLR2-Mediated Migration of Activated Dendritic Cells in an Ex Vivo Human Skin Model

    Science.gov (United States)

    Wagemakers, Alex; van ‘t Veer, Cornelis; Oei, Anneke; van der Pot, Wouter J.; Ahmed, Kalam; van der Poll, Tom; Geijtenbeek, Teunis B. H.; Hovius, Joppe W. R.

    2016-01-01

    Borrelia burgdorferi is transmitted into the skin of the host where it encounters and interacts with two dendritic cell (DC) subsets; Langerhans cells (LCs) and dermal DCs (DDCs). These cells recognize pathogens via pattern recognition receptors, mature and migrate out of the skin into draining lymph nodes, where they orchestrate adaptive immune responses. In order to investigate the response of skin DCs during the early immunopathogenesis of Lyme borreliosis, we injected B. burgdorferi intradermally into full-thickness human skin and studied the migration of DCs out of the skin, the activation profile and phenotype of migrated cells. We found a significant increase in the migration of LCs and DDCs in response to B. burgdorferi. Notably, migration was prevented by blocking TLR2. DCs migrated from skin inoculated with higher numbers of spirochetes expressed significantly higher levels of CD83 and produced pro-inflammatory cytokines. No difference was observed in the expression of HLA-DR, CD86, CD38, or CCR7. To conclude, we have established an ex vivo human skin model to study DC-B. burgdorferi interactions. Using this model, we have demonstrated that B. burgdorferi-induced DC migration is mediated by TLR2. Our findings underscore the utility of this model as a valuable tool to study immunity to spirochetal infections. PMID:27695100

  12. A life stage of particle-laden rat dendritic cells in vivo: their terminal division, active phagocytosis, and translocation from the liver to the draining lymph

    OpenAIRE

    1996-01-01

    Initiation of an adoptive immune response against pathogenic organisms, such as bacteria and fungi, may involve phagocytic activity of dendritic cells (DC) or their immature precursors as a prelude to antigen processing and presentation. After intravenous injection of rats with particulate matter, particle-laden cells were detected in the peripheral hepatic lymph. Since it has been known there is a constant efflux of DC from nonlymphoid organs into the draining peripheral lymph, we examined w...

  13. Transforming growth factor beta-activated kinase 1 (TAK1)-dependent checkpoint in the survival of dendritic cells promotes immune homeostasis and function

    OpenAIRE

    Wang, Yanyan; Huang, Gonghua; Vogel, Peter; Neale, Geoffrey; Reizis, Boris; Chi, Hongbo

    2012-01-01

    Homeostatic control of dendritic cell (DC) survival is crucial for adaptive immunity, but the molecular mechanism is not well defined. Moreover, how DCs influence immune homeostasis under steady state remains unclear. Combining DC-specific and -inducible deletion systems, we report that transforming growth factor beta-activated kinase 1 (TAK1) is an essential regulator of DC survival and immune system homeostasis and function. Deficiency of TAK1 in CD11c+ cells induced markedly elevated apopt...

  14. Interleukin-1 and Interferon-γ Orchestrate β-Glucan-Activated Human Dendritic Cell Programming via IκB-ζ Modulation

    OpenAIRE

    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 tr...

  15. Disruption of Early Tumor Necrosis Factor Alpha Signaling Prevents Classical Activation of Dendritic Cells in Lung-Associated Lymph Nodes and Development of Protective Immunity against Cryptococcal Infection

    Directory of Open Access Journals (Sweden)

    Jintao Xu

    2016-07-01

    Full Text Available Anti-tumor necrosis factor alpha (anti-TNF-α therapies have been increasingly used to treat inflammatory diseases and are associated with increased risk of invasive fungal infections, including Cryptococcus neoformans infection. Using a mouse model of cryptococcal infection, we investigated the mechanism by which disruption of early TNF-α signaling results in the development of nonprotective immunity against C. neoformans. We found that transient depletion of TNF-α inhibited pulmonary fungal clearance and enhanced extrapulmonary dissemination of C. neoformans during the adaptive phase of the immune response. Higher fungal burdens in TNF-α-depleted mice were accompanied by markedly impaired Th1 and Th17 responses in the infected lungs. Furthermore, early TNF-α depletion also resulted in disrupted transcriptional initiation of the Th17 polarization program and subsequent upregulation of Th1 genes in CD4+ T cells in the lung-associated lymph nodes (LALN of C. neoformans-infected mice. These defects in LALN T cell responses were preceded by a dramatic shift from a classical toward an alternative activation of dendritic cells (DC in the LALN of TNF-α-depleted mice. Taken together, our results indicate that early TNF-α signaling is required for optimal DC activation, and the initial Th17 response followed by Th1 transcriptional prepolarization of T cells in the LALN, which further drives the development of protective immunity against cryptococcal infection in the lungs. Thus, administration of anti-TNF-α may introduce a particularly greater risk for newly acquired fungal infections that require generation of protective Th1/Th17 responses for their containment and clearance.

  16. Loss of the TGFβ-activating integrin αvβ8 on dendritic cells protects mice from chronic intestinal parasitic infection via control of type 2 immunity.

    Directory of Open Access Journals (Sweden)

    John J Worthington

    Full Text Available Chronic intestinal parasite infection is a major global health problem, but mechanisms that promote chronicity are poorly understood. Here we describe a novel cellular and molecular pathway involved in the development of chronic intestinal parasite infection. We show that, early during development of chronic infection with the murine intestinal parasite Trichuris muris, TGFβ signalling in CD4+ T-cells is induced and that antibody-mediated inhibition of TGFβ function results in protection from infection. Mechanistically, we find that enhanced TGFβ signalling in CD4+ T-cells during infection involves expression of the TGFβ-activating integrin αvβ8 by dendritic cells (DCs, which we have previously shown is highly expressed by a subset of DCs in the intestine. Importantly, mice lacking integrin αvβ8 on DCs were completely resistant to chronic infection with T. muris, indicating an important functional role for integrin αvβ8-mediated TGFβ activation in promoting chronic infection. Protection from infection was dependent on CD4+ T-cells, but appeared independent of Foxp3+ Tregs. Instead, mice lacking integrin αvβ8 expression on DCs displayed an early increase in production of the protective type 2 cytokine IL-13 by CD4+ T-cells, and inhibition of this increase by crossing mice to IL-4 knockout mice restored parasite infection. Our results therefore provide novel insights into how type 2 immunity is controlled in the intestine, and may help contribute to development of new therapies aimed at promoting expulsion of gut helminths.

  17. Co-transfection of dendritic cells with AFP and IL-2 genes enhances the induction of tumor antigen-specific antitumor immunity.

    Science.gov (United States)

    Yang, Jing-Yue; Li, Xiao; Gao, Li; Teng, Zeng-Hui; Liu, Wen-Chao

    2012-10-01

    Dendritic cells (DCs) are highly efficient, specialized antigen-presenting cells and DCs transfected with tumor-related antigens are regarded as promising vaccines in cancer immunotherapy. The aim of the present study was to investigate whether DCs co-transfected with the α-fetoprotein (AFP) and human interleukin-2 (IL-2) genes were able to induce stronger therapeutic antitumor immunity in transfected DCs. In this study, DCs from hepatocellular carcinoma (HCC) patients were co-transfected with the IL-2 gene and/or the AFP gene. The reverse transcription-PCR (RT-PCR) data revealed that the DCs transfected with the adenovirus AdAFP/IL-2 expressed AFP and IL-2. The DCs co-transfected with IL-2 and AFP (AFP/IL-2-DCs) enhanced the cytotoxicities of cytotoxic T lymphocytes (CTLs) and increased the production of IL-2 and interferon-γ significantly compared with their AFP-DC, green fluorescent protein (GFP)-DC, DC or phosphate-buffered saline (PBS) counterparts. In vivo data suggested that immunization with AFP-DCs enhances antigen-specific antitumor efficacy more potently than immunization with IL-2-DCs or AFP-DCs. These findings provide a potential strategy to improve the efficacy of DC-based tumor vaccines.

  18. Leishmania mexicana promastigotes down regulate JNK and p-38 MAPK activation: Role in the inhibition of camptothecin-induced apoptosis of monocyte-derived dendritic cells.

    Science.gov (United States)

    Rodríguez-González, Jorge; Wilkins-Rodríguez, Arturo; Argueta-Donohué, Jesús; Aguirre-García, Magdalena; Gutiérrez-Kobeh, Laila

    2016-04-01

    Dendritic cells (DC) are one of the principal host cells of the obligate intracellular parasite Leishmania. Inhibition of host cell apoptosis is a strategy employed by multiple pathogens to ensure their survival in the infected cell. We have previously shown that the infection of monocyte-derived dendritic cells (moDC) with Leishmania mexicana inhibits campthotecin-induced apoptosis. Nevertheless, the mechanisms involved in the inhibition of apoptosis of dendritic cells by Leishmania have not been established. Mitogen-activated protein kinases (MAPK) are key participants in the process of apoptosis and different species of Leishmania have been shown to regulate these kinases. In the present study, we analyzed the effect of L. mexicana promastigotes in the activation of JNK and p38 MAP kinase and their participation in the inhibition of apoptosis. The infection of moDC with L. mexicana promastigotes diminished significantly the phosphorylation of the MAP kinases JNK and p38. The inhibition of both kinases diminished DNA fragmentation, but in a major extent was the reduction of DNA fragmentation when JNK was inhibited. The capacity of L. mexicana promastigotes to diminish MAP kinases activation is probably one of the strategies employed to delay apoptosis induction in the infected moDC and may have implications for Leishmania pathogenesis by favoring the invasion of its host and the persistence of the parasite in the infected cells.

  19. Nocardia farcinica Activates Human Dendritic Cells and Induces Secretion of Interleukin-23 (IL-23) Rather than IL-12p70

    Science.gov (United States)

    Eisenblätter, Martin; Buchal, Ariane; Gayum, Hermine; Jasny, Edith; Renner Viveros, Pablo; Ulrichs, Timo; Schneider, Thomas; Schumann, Ralf R.; Zweigner, Janine

    2012-01-01

    Studying the interaction of dendritic cells (DCs) with bacteria controlled by T-cell-mediated immune responses may reveal novel adjuvants for the induction of cellular immunity. Murine studies and the observation that nocardias infect predominantly immunosuppressed patients have suggested that these bacteria may possess an adjuvant potential. Moreover, adjuvants on the basis of the nocardial cell wall have been applied in clinical studies. Since the handling of adjuvants by DCs may determine the type of immune responses induced by a vaccine, the present study aimed at investigating the interaction of immature human monocyte-derived DCs with live or inactivated Nocardia farcinica in vitro and determining the cellular phenotypic changes as well as alterations in characteristic functions, such as phagocytosis, induction of T-cell proliferation, and cytokine secretion. Human DCs ingested N. farcinica and eradicated the bacterium intracellularly. DCs exposed to inactivated N. farcinica were activated, i.e., they developed a mature phenotype, downregulated their phagocytic capacity, and stimulated allogeneic T cells in mixed leukocyte reactions. Soluble factors were not involved in this process. To elucidate the potential adjuvant effect of N. farcinica on the induction of T-cell-mediated immune responses, we characterized the cytokines produced by nocardia-exposed DCs and detected substantial amounts of tumor necrosis factor alpha (TNF-α) and interleukin-12 p40 (IL-12p40). However, nocardia-treated DCs secreted only small amounts of IL-12p70, which were significantly smaller than the amounts of IL-23. Thus, N. farcinica activates DCs, but adjuvants based on this bacterium may have only a limited capacity to induce Th1 immune responses. PMID:22988018

  20. Poly-I:C Decreases Dendritic Cell Viability Independent of PKR Activation

    DEFF Research Database (Denmark)

    Larsen, Hjalte List; Pedersen, Anders Elm

    2012-01-01

    ). We and others have previously performed a comprehensive comparison of sDCs and αDC1s. Here we demonstrate that the viability of αDC1s is lowered compared to sDCs and that DC apoptosis is medi- ated by Poly-I:C. We speculated that activation of protein kinase R (PKR) could mediate the observed...

  1. PrPSc accumulation in neuronal plasma membranes links Notch-1 activation to dendritic degeneration in prion diseases

    Directory of Open Access Journals (Sweden)

    DeArmond Stephen J

    2010-01-01

    Full Text Available Abstract Prion diseases are disorders of protein conformation in which PrPC, the normal cellular conformer, is converted to an abnormal, protease-resistant conformer rPrPSc. Approximately 80% of rPrPSc accumulates in neuronal plasma membranes where it changes their physical properties and profoundly affects membrane functions. In this review we explain how rPrPSc is transported along axons to presynaptic boutons and how we envision the conversion of PrPC to rPrPSc in the postsynaptic membrane. This information is a prerequisite to the second half of this review in which we present evidence that rPrPSc accumulation in synaptic regions links Notch-1 signaling with the dendritic degeneration. The hypothesis that the Notch-1 intracellular domain, NICD, is involved in prion disease was tested by treating prion-infected mice with the γ-secretase inhibitor (GSI LY411575, with quinacrine (Qa, and with the combination of GSI + Qa. Surprisingly, treatment with GSI alone markedly decreased NICD but did not prevent dendritic degeneration. Qa alone produced near normal dendritic trees. The combined GSI + Qa treatment resulted in a richer dendritic tree than in controls. We speculate that treatment with GSI alone inhibited both stimulators and inhibitors of dendritic growth. With the combined GSI + Qa treatment, Qa modulated the effect of GSI perhaps by destabilizing membrane rafts. GSI + Qa decreased PrPSc in the neocortex and the hippocampus by 95%, but only by 50% in the thalamus where disease was begun by intrathalamic inoculation of prions. The results of this study indicate that GSI + Qa work synergistically to prevent dendrite degeneration and to block formation of PrPSc.

  2. Gut Dendritic Cell Activation Links an Altered Colonic Microbiome to Mucosal and Systemic T Cell Activation in Untreated HIV-1 infection

    Science.gov (United States)

    Dillon, SM; Lee, EJ; Kotter, CV; Austin, GL; Gianella, S; Siewe, B; Smith, DM; Landay, AL; McManus, MC; Robertson, CE; Frank, DN; McCarter, MD; Wilson, CC

    2015-01-01

    HIV-1-associated disruption of intestinal homeostasis is a major factor contributing to chronic immune activation and inflammation. Dendritic cells (DCs) are crucial in maintaining intestinal homeostasis, but the impact of HIV-1 infection on intestinal DC number and function has not been extensively studied. We compared the frequency and activation/maturation status of colonic myeloid DC (mDC) subsets (CD1c+ and CD1cneg) and plasmacytoid DCs in untreated HIV-1-infected subjects with uninfected controls. Colonic mDCs in HIV-1-infected subjects had increased CD40 but decreased CD83 expression, and CD40 expression on CD1c+ mDCs positively correlated with mucosal HIV-1 viral load, with mucosal and systemic cytokine production, and with frequencies of activated colon and blood T cells. Percent of CD83+CD1c+ mDCs negatively correlated with frequencies of IFN-γ-producing colon CD4+ and CD8+ T cells. CD40 expression on CD1c+ mDCs positively associated with abundance of high prevalence mucosal Prevotella copri and P. stercorea, but negatively associated with a number of low prevalence mucosal species including Rumminococcus bromii. CD1c+ mDC cytokine production was greater in response to in vitro stimulation with Prevotella species relative to R. bromii. These findings suggest that during HIV infection, colonic mDCs become activated upon exposure to mucosal pathobiont bacteria leading to mucosal and systemic immune activation. PMID:25921339

  3. Natural Killer Cells Are Activated by Lactic Acid Bacteria-Matured Dendritic Cells

    DEFF Research Database (Denmark)

    Fink, Lisbeth Nielsen; Christensen, Hanne Risager; Frøkiær, Hanne

    of certain lactic acid bacteria has been shown to increase in vivo NK cytotoxicity. Here, we investigated how human gut flora-derived lactobacilli affect NK cells in vitro, by measuring proliferation and IFN-gamma production of human NK cells upon bacterial stimulation. Human peripheral blood NK cells were...... with lactic acid bacteria will affect NK cell activation. Such activation of NK cells may potentially skew an on-going or subsequent immune response towards a Th1 response....... incubated with 10 microg/ml UV-inactivated bacteria or 10 microg/ml phytohemagglutinin (PHA) for four days. Proliferation was assessed by incorporation of radioactive thymidine into NK cell DNA. The IFN-gamma concentration was measured by ELISA. Incubation of NK cells with a Lactobacillus acidophilus strain...

  4. Demethylation of Cancer/Testis Antigens and CpG ODN Stimulation Enhance Dendritic Cell and Cytotoxic T Lymphocyte Function in a Mouse Mammary Model

    Directory of Open Access Journals (Sweden)

    Jun-Zhong Sun

    2013-01-01

    Full Text Available Background. Cancer/testis antigens (CTAs are ideal targets for cancer immunotherapy in virtue of their restricted expression profile in normal tissues. However, CTA-targeted immunotherapy has been rather disappointing clinical setting for CTAs are downregulated by cytosine-phosphate-guanosine (CpG methylation in their promoter regions, so that tumor cells have low immunogenicity. Methods. We reinduced mouse CTA P1A through demethylation process and generated P1A-specific cytotoxic lymphocytes (CTLs by immunizing BALB/c (H-2d mice with dendritic cells pulsed with a P1A-specific peptide and CpG oligodeoxynucleotide (ODN immune adjuvant. Results. We found that demethylation and CpG ODN immune adjuvant stimulation facilitated DC maturation and enhanced the allogenic capacity of P1A-specific CTLs against target cells both in vitro and in vivo. Conclusions. Our results suggested that CTA induction and immune adjuvant stimulation is a feasible strategy in cancer immunotherapy.

  5. Synaptic function for the Nogo-66 receptor NgR1: regulation of dendritic spine morphology and activity-dependent synaptic strength.

    Science.gov (United States)

    Lee, Hakjoo; Raiker, Stephen J; Venkatesh, Karthik; Geary, Rebecca; Robak, Laurie A; Zhang, Yu; Yeh, Hermes H; Shrager, Peter; Giger, Roman J

    2008-03-12

    In the mature nervous system, changes in synaptic strength correlate with changes in neuronal structure. Members of the Nogo-66 receptor family have been implicated in regulating neuronal morphology. Nogo-66 receptor 1 (NgR1) supports binding of the myelin inhibitors Nogo-A, MAG (myelin-associated glycoprotein), and OMgp (oligodendrocyte myelin glycoprotein), and is important for growth cone collapse in response to acutely presented inhibitors in vitro. After injury to the corticospinal tract, NgR1 limits axon collateral sprouting but is not important for blocking long-distance regenerative growth in vivo. Here, we report on a novel interaction between NgR1 and select members of the fibroblast growth factor (FGF) family. FGF1 and FGF2 bind directly and with high affinity to NgR1 but not to NgR2 or NgR3. In primary cortical neurons, ectopic NgR1 inhibits FGF2-elicited axonal branching. Loss of NgR1 results in altered spine morphologies along apical dendrites of hippocampal CA1 neurons in vivo. Analysis of synaptosomal fractions revealed that NgR1 is enriched synaptically in the hippocampus. Physiological studies at Schaffer collateral-CA1 synapses uncovered a synaptic function for NgR1. Loss of NgR1 leads to FGF2-dependent enhancement of long-term potentiation (LTP) without altering basal synaptic transmission or short-term plasticity. NgR1 and FGF receptor 1 (FGFR1) are colocalized to synapses, and mechanistic studies revealed that FGFR kinase activity is necessary for FGF2-elicited enhancement of hippocampal LTP in NgR1 mutants. In addition, loss of NgR1 attenuates long-term depression of synaptic transmission at Schaffer collateral-CA1 synapses. Together, our findings establish that physiological NgR1 signaling regulates activity-dependent synaptic strength and uncover neuronal NgR1 as a regulator of synaptic plasticity.

  6. Bordetella pertussis commits human dendritic cells to promote a Th1/Th17 response through the activity of adenylate cyclase toxin and MAPK-pathways.

    Directory of Open Access Journals (Sweden)

    Giorgio Fedele

    Full Text Available The complex pathology of B. pertussis infection is due to multiple virulence factors having disparate effects on different cell types. We focused our investigation on the ability of B. pertussis to modulate host immunity, in particular on the role played by adenylate cyclase toxin (CyaA, an important virulence factor of B. pertussis. As a tool, we used human monocyte derived dendritic cells (MDDC, an ex vivo model useful for the evaluation of the regulatory potential of DC on T cell immune responses. The work compared MDDC functions after encounter with wild-type B. pertussis (BpWT or a mutant lacking CyaA (BpCyaA-, or the BpCyaA- strain supplemented with either the fully functional CyaA or a derivative, CyaA*, lacking adenylate cyclase activity. As a first step, MDDC maturation, cytokine production, and modulation of T helper cell polarization were evaluated. As a second step, engagement of Toll-like receptors (TLR 2 and TLR4 by B. pertussis and the signaling events connected to this were analyzed. These approaches allowed us to demonstrate that CyaA expressed by B. pertussis strongly interferes with DC functions, by reducing the expression of phenotypic markers and immunomodulatory cytokines, and blocking IL-12p70 production. B. pertussis-treated MDDC promoted a mixed Th1/Th17 polarization, and the activity of CyaA altered the Th1/Th17 balance, enhancing Th17 and limiting Th1 expansion. We also demonstrated that Th1 effectors are induced by B. pertussis-MDDC in the absence of IL-12p70 through an ERK1/2 dependent mechanism, and that p38 MAPK is essential for MDDC-driven Th17 expansion. The data suggest that CyaA mediates an escape strategy for the bacterium, since it reduces Th1 immunity and increases Th17 responses thought to be responsible, when the response is exacerbated, for enhanced lung inflammation and injury.

  7. Enhanced activation of dendritic cells by autologous apoptotic microvesicles in MRL/lpr mice

    NARCIS (Netherlands)

    Dieker, J.W.; Hilbrands, L.B.; Thielen, A.; Dijkman, H.B.P.M.; Berden, J.H.M.; Vlag, J. van der

    2015-01-01

    INTRODUCTION: Systemic lupus erythematosus is associated with a persistent circulation of modified autoantigen-containing apoptotic debris that might be capable of breaking tolerance. We aimed to evaluate apoptotic microvesicles obtained from lupus or control mice for the presence of apoptosis-assoc

  8. White button mushroom enhances maturation of bone marrow derived dendritic cells and their antigen presenting function in mice

    Science.gov (United States)

    Mushrooms have been shown to enhance immune response, which contributes to their anti-tumor property. White button mushrooms (Agaricus bisporus) (WBM) constitute 90 percent of the total mushrooms consumed in the United States; however, the health benefit of this strain in general is not well studied...

  9. Excitatory synapses on dendritic shafts of the caudal basal amygdala exhibit elevated levels of GABAA receptor α4 subunits following the induction of activity-based anorexia.

    Science.gov (United States)

    Wable, Gauri S; Barbarich-Marsteller, Nicole C; Chowdhury, Tara G; Sabaliauskas, Nicole A; Farb, Claudia R; Aoki, Chiye

    2014-01-01

    Anorexia nervosa (AN) is an eating disorder characterized by self-imposed severe starvation, excessive exercise, and anxiety. The onset of AN is most often at puberty, suggesting that gonadal hormonal fluctuations may contribute to AN vulnerability. Activity-based anorexia (ABA) is an animal model that reproduces some of the behavioral phenotypes of AN, including the paradoxical increase in voluntary exercise following food restriction. The basal amygdala as well as the GABAergic system regulate trait anxiety. We therefore examined the subcellular distribution of GABA receptors (GABARs) in the basal amygdala of female pubertal rats and specifically of their α4 subunits, because expression of α4-containing GABARs is regulated by gonadal hormone fluctuations. Moreover, because these GABARs reduce neuronal excitability through shunting of EPSPs, we quantified the frequency of occurrence of these GABARs adjacent to excitatory synapses. Electron microscopic immunoctychemistry revealed no change in the frequency of association of α4 subunits with excitatory synapses on dendritic spines, whether in the anterior (Bregma -2.8 mm) or caudal (Bregma -3.8 mm) portion of the basal amygdala. Sholl analysis of golgi-stained neurons also revealed no change in the extent of dendritic branching by these densely spiny, pyramidal-like neurons. However, there was an increase of membranous α4 subunits near excitatory synapses on dendritic shafts, specifically in the caudal basal amygdala, and this was accompanied by a rise of α4 subunits intracellularly. Because most dendritic shafts exhibiting excitatory synapses are GABAergic interneurons, the results predict disinhibition, which would increase excitability of the amygdaloid network, in turn augmenting ABA animals' anxiety.

  10. IL-1β-Dependent Activation of Dendritic Epidermal T Cells in Contact Hypersensitivity

    DEFF Research Database (Denmark)

    Nielsen, Morten M; Lovato, Paola; Macleod, Amanda S

    2014-01-01

    Substances that penetrate the skin surface can act as allergens and induce a T cell-mediated inflammatory skin disease called contact hypersensitivity (CHS). IL-17 is a key cytokine in CHS and was originally thought to be produced solely by CD4(+) T cells. However, it is now known that several cell...... in CHS. Thus, more IL-17-producing DETCs appear in the skin following exposure to DNFB in wild-type mice, and DNFB-induced ear swelling is reduced by ∼50% in TCRδ(-/-) mice compared with wild-type mice. In accordance, DNFB-induced ear swelling was reduced by ∼50% in IL-17(-/-) mice. We show that DNFB...... triggers DETC activation and IL-1β production in the skin and that keratinocytes produce IL-1β when stimulated with DNFB. We find that DETCs activated in vitro by incubation with anti-CD3 and IL-1β produce IL-17. Importantly, we demonstrate that the IL-1R antagonist anakinra significantly reduces CHS...

  11. Fasciola hepatica Kunitz type molecule decreases dendritic cell activation and their ability to induce inflammatory responses.

    Directory of Open Access Journals (Sweden)

    Cristian R Falcón

    Full Text Available The complete repertoire of proteins with immunomodulatory activity in Fasciola hepatica (Fh has not yet been fully described. Here, we demonstrated that Fh total extract (TE reduced LPS-induced DC maturation, and the DC ability to induce allogeneic responses. After TE fractionating, a fraction lower than 10 kDa (F<10 kDa was able to maintain the TE properties to modulate the DC pro- and anti-inflammatory cytokine production induced by LPS. In addition, TE or F<10 kDa treatment decreased the ability of immature DC to stimulate the allogeneic responses and induced a novo allogeneic CD4+CD25+Foxp3+ T cells. In contrast, treatment of DC with T/L or F<10 kDa plus LPS (F<10/L induced a regulatory IL-27 dependent mechanism that diminished the proliferative and Th1 and Th17 allogeneic responses. Finally, we showed that a Kunitz type molecule (Fh-KTM, present in F<10 kDa, was responsible for suppressing pro-inflammatory cytokine production in LPS-activated DC, by printing tolerogenic features on DC that impaired their ability to induce inflammatory responses. These results suggest a modulatory role for this protein, which may be involved in the immune evasion mechanisms of the parasite.

  12. Enhanced active swimming in viscoelastic fluids

    CERN Document Server

    Riley, Emily E

    2014-01-01

    Swimming microorganisms often self propel in fluids with complex rheology. While past theoretical work indicates that fluid viscoelasticity should hinder their locomotion, recent experiments on waving swimmers suggest a possible non-Newtonian enhancement of locomotion. We suggest a physical mechanism, based on fluid-structure interaction, leading to swimming in a viscoelastic fluid at a higher speed than in a Newtonian one. Using Taylor's two-dimensional swimming sheet model, we solve for the shape of an active swimmer as a balance between the external fluid stresses, the internal driving moments, and the passive elastic resistance. We show that this dynamic balance leads to a generic transition from hindered rigid swimming to enhanced flexible locomotion. The results are physically interpreted as due to a viscoelastic suction increasing the swimming amplitude in a non-Newtonian fluid and overcoming viscoelastic damping.

  13. Increased frequency of CD16+monocytes and the presence of activated dendritic cells in salivary glands in primary Sjogren syndrome

    NARCIS (Netherlands)

    Wildenberg, M. E.; Welzen-Coppens, J. M. C.; van Helden-Meeuwsen, C. G.; Bootsma, H.; Vissink, A.; van Rooijen, N.; de Merwe, J. P. van; Drexhage, H. A.; Versnel, M. A.

    2009-01-01

    Objectives: In the salivary glands of patients with primary Sjogren Syndrome (pSjS) an accumulation of dendritic cells (DCs) is seen, which is thought to play a role in stimulating local inflammation. Aberrancies in subsets of monocytes, generally considered the blood precursors for DCs, may play a

  14. Heterogeneity of mouse spleen dendritic cells: in vivo phagocytic activity, expression of macrophage markers, and subpopulation turnover

    NARCIS (Netherlands)

    P.J. Leenen (Pieter); K. Radosevic; J.S. Voerman (Jane); B. Salomon; N. van Rooijen (Nico); D. Klatzmann; W. van Ewijk (Willem)

    1998-01-01

    textabstractIn the normal mouse spleen, two distinct populations of dendritic cells (DC) are present that differ in microanatomical location. The major population of marginal DC is found in the "marginal zone bridging channels" and extends into the red pulp. The interdi

  15. Involvement of α2-antiplasmin in dendritic growth of hippocampal neurons.

    Science.gov (United States)

    Kawashita, Eri; Kanno, Yosuke; Asayama, Haruka; Okada, Kiyotaka; Ueshima, Shigeru; Matsuo, Osamu; Matsuno, Hiroyuki

    2013-07-01

    The α2-Antiplasmin (α2AP) protein is known as a principal physiological inhibitor of plasmin, but we previously demonstrated that it acts as a regulatory factor for cellular functions independent of plasmin. α2AP is highly expressed in the hippocampus, suggesting a potential role for α2AP in hippocampal neuronal functions. However, the role for α2AP was unclear. This study is the first to investigate the involvement of α2AP in the dendritic growth of hippocampal neurons. The expression of microtubule-associated protein 2, which contributes to neurite initiation and neuronal growth, was lower in the neurons from α2AP⁻/⁻ mice than in the neurons from α2AP⁺/⁺ mice. Exogenous treatment with α2AP enhanced the microtubule-associated protein 2 expression, dendritic growth and filopodia formation in the neurons. This study also elucidated the mechanism underlying the α2AP-induced dendritic growth. Aprotinin, another plasmin inhibitor, had little effect on the dendritic growth of neurons, and α2AP induced its expression in the neurons from plaminogen⁻/⁻ mice. The activation of p38 MAPK was involved in the α2AP-induced dendritic growth. Therefore, our findings suggest that α2AP induces dendritic growth in hippocampal neurons through p38 MAPK activation, independent of plasmin, providing new insights into the role of α2AP in the CNS.

  16. Soluble ICAM-5, a product of activity dependent proteolysis, increases mEPSC frequency and dendritic expression of GluA1.

    Directory of Open Access Journals (Sweden)

    Irina Lonskaya

    Full Text Available Matrix metalloproteinases (MMPs are zinc dependent endopeptidases that can be released from neurons in an activity dependent manner to play a role in varied forms of learning and memory. MMP inhibitors impair hippocampal long term potentiation (LTP, spatial memory, and behavioral correlates of drug addiction. Since MMPs are thought to influence LTP through a β1 integrin dependent mechanism, it has been suggested that these enzymes cleave specific substrates to generate integrin binding ligands. In previously published work, we have shown that neuronal activity stimulates rapid MMP dependent shedding of intercellular adhesion molecule-5 (ICAM-5, a synaptic adhesion molecule expressed on dendrites of the telencephalon. We have also shown that the ICAM-5 ectodomain can interact with β1 integrins to stimulate integrin dependent phosphorylation of cofilin, an event that occurs with dendritic spine maturation and LTP. In the current study, we investigate the potential for the ICAM-5 ectodomain to stimulate changes in α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptor (AMPAR dependent glutamatergic transmission. Single cell recordings show that the ICAM-5 ectodomain stimulates an increase in the frequency, but not the amplitude, of AMPA mini excitatory post synaptic currents (mEPSCs. With biotinylation and precipitation assays, we also show that the ICAM-5 ectodomain stimulates an increase in membrane levels of GluA1, but not GluA2, AMPAR subunits. In addition, we observe an ICAM-5 associated increase in GluA1 phosphorylation at serine 845. Concomitantly, ICAM-5 affects an increase in GluA1 surface staining along dendrites without affecting an increase in dendritic spine number. Together these data are consistent with the possibility that soluble ICAM-5 increases glutamatergic transmission and that post-synaptic changes, including increased phosphorylation and dendritic insertion of GluA1, could contribute. We suggest that future studies

  17. IL-12 suppression, enhanced endocytosis and up-regulation of MHC-Ⅱ and CD80 in dendritic cells during experimental endotoxin tolerance

    Institute of Scientific and Technical Information of China (English)

    Jing ZHANG; Jie-ming QU; Li-xian HE

    2009-01-01

    Aim: The aim of this study was to investigate endocytosis, MHC-Ⅱ expression and co-stimulatory molecule expression, as well as interleukin-12 (IL-12) production, in bone marrow dendritic cells (DCs) derived from endotoxin tolerant mice.Methods: Endotoxin tolerance was induced in C57BL/10J mice through four consecutive daily intraperitoneal injections of 1.0 mg/kg of 055:B5 Escherichia coli lipopolysaccharide (LPS). Bone marrow DCs were isolated in the presence of GM-CSF and IL-4 and purified by anti-CD11c Micro beads. FITC-dextran uptake by DCs was tested by flow cytometric analysis and the percentage of dextran-containing cells was calculated using a fluorescence microscope. The expression of surface MHC-Ⅱ, CD40, CD80, and CD86 was also detected by flow cytometric analysis. An ELISA was used for the measurement of IL-12 production by DCs with or without LPS stimulation.Results: Endotoxin tolerance was successfully induced in C57BL/10J mice, evidenced by an attenuated elevation of systemic TNF-α. DCs from endotoxin tolerant mice possessed enhanced dextran endocytosis ability. The expression of surface MHC-Ⅱ and CD80 was higher in DCs from endotoxin tolerant mice than in DCs from control mice, whereas the expression of CD40 and CD86 was not altered. Compared with DCs from normal control mice, DCs from endotoxin tolerant mice produced less IL-12 after subsequent in vitro stimulation with LPS.Conclusion: These data suggest enhanced endocytosis, selective up-regulation of MHC-Ⅱ and CD80 and IL-12 suppression in DCs during in vivo induction of endotoxin tolerance.

  18. Enhancement of Aminoacylase Activity by Sodium Citrate

    Institute of Scientific and Technical Information of China (English)

    于范利; 曹志方; 李森; 周海梦

    2001-01-01

    Kidney and other tissues of animals and humans have a high concentration of citrate which is an important intermediate substance in the citrate cycle. Citrate may play an important physiological role in metabolism. In this paper, we studied the interaction of the sodium salt of citrate with aminoacylase which is an important enzyme in metabolism and found sodium citrate can enhance the activity of aminoacylase. The maximum enzyme activity induced by sodium citrate increased approximately 3 folds over the enzyme activity without sodium citrate. The initial reaction rates (Ⅴ) for different concentrations of sodium citrate were obtained, showing that sodium citrate is a non-competitive activator. The result of the ANS binding fluorescence measurements for aminoacylase indicated that increasing sodium citrate concentrations markedly increased the ANS binding fluorescence with a blue shift of the emission spectra peak. This suggests the formation of more hydrophobic regions. Aggregates formed quickly when aminoacylase was incubated with sodium citrate (0.3 mol/L) and guanidinium chloride (0- 3. 5 mol/L). Aminoacylase lost enzyme activity in the guanidinium chloride more quickly in the presence of sodium citrate than in the absence of sodium citrate. The intrinsic fluorescence emission intensity decreased more quickly and the red shift of the emission spectra peak was larger than that without sodium citrate.

  19. Activity of the principal cells of the olfactory bulb promotes a structural dynamic on the distal dendrites of immature adult-born granule cells via activation of NMDA receptors.

    Science.gov (United States)

    Breton-Provencher, Vincent; Coté, Daniel; Saghatelyan, Armen

    2014-01-29

    The adult olfactory bulb is continuously supplied with neuronal precursors that differentiate into granule and periglomerular cells. Little is known about the structural dynamic of adult-born granule cells (GCs) at their different maturational stages, the mechanisms controlling the integration of new neurons into the pre-existing neuronal circuitry, or the role of principal cell activity in these processes. We used two-photon time-lapse imaging to reveal a high level of filopodia formation and retraction on the distal dendrites of adult-born GCs at their early maturational stages. This dynamic decreased as the adult-born interneurons matured. Filopodia formation/retraction on the dendrites of adult-born GCs at the early maturational stages depended on the activation of NMDA receptors (NMDARs). The stimulation of mitral cells using a pattern that mimics activity of these principal neurons to odor presentation promotes the NMDAR-dependent filopodia dynamic of adult-born GCs during their early but not late maturational stages. Moreover, NMDA iontophoresis was sufficient to induce the formation of new filopodia on the distal dendrites of immature adult-born GCs. The maturation of adult-born interneurons was accompanied by a progressive hyperpolarization of the membrane potential and an increased Mg(2+) block of NMDARs. Decreasing the extracellular Mg(2+) concentration led to filopodia formation on the dendrites of mature adult-born GCs following NMDA iontophoresis. Our findings reveal an increased structural dynamic of adult-born GCs during the early stages of their integration into the mouse bulbar circuitry and highlight a critical period during which the principal cells' activity influences filopodia formation/retraction on the dendrites of interneurons.

  20. IL-25 promotes Th2 immunity responses in airway inflammation of asthmatic mice via activation of dendritic cells.

    Science.gov (United States)

    Hongjia, Li; Caiqing, Zhang; Degan, Lu; Fen, Liu; Chao, Wang; Jinxiang, Wu; Liang, Dong

    2014-08-01

    Allergic asthma occurs as a consequence of inappropriate immunologic inflammation to allergens and characterized by Th2 adaptive immune response. Recent studies indicated that interleukin (IL)-25, a member of the IL-17 cytokine family, had been implicated in inducing Th2 cell-dependent inflammation in airway epithelium and IL-25-deficient mice exhibit impaired Th2 immunity responses; however, how these cytokines influence innate immune responses remains poorly understood. In this study, we used ovalbumin (OVA) sensitization and challenge to induce the murine asthmatic model and confirmed by histological analysis of lung tissues and serum levels of total and OVA-specific immunoglobulin (Ig)-E. The expression of IL-25 was detected by quantitative real-time PCR and immunohistochemistry, respectively, and the dendritic cells (DCs) activation was detected by levels of CD80 and CD86 in bronchoalveolar lavage fluid (BALF) by flow cytometry. The mice sensitized and challenged with OVA showed high expression of IL-25 in both mRNA and protein levels in lungs. We detected the expression of CD80 and CD86 in BALF was also increased. A tight correlation between IL-25 mRNA and other Th2 cells producing cytokines such as IL-4, IL-5, and IL-13 in BALF was identified. Furthermore, when the asthmatic mice were treated with inhaled corticosteroids, the inflammatory cells infiltration and the inflammatory cytokines secretion were significantly decreased. In this study, we show that IL-25 promoted the accumulation of co-stimulatory molecules of CD80 and CD86 on DCs and then induced the differentiation of prime naive CD4(+) T cells to become proinflammatory Th2 cells and promoted Th2 cytokine responses in OVA-induced airway inflammation. The ability of IL-25 to promote the activation and differentiation of DCs population was identified as a link between the IL-17 cytokine family and the innate immune response and suggested a previously unrecognized innate immune pathway that promotes Th2

  1. Atg5 but not Atg7 in dendritic cells enhances IL-2 and IFN-γ production by Toxoplasma gondii-reactive CD4+ T cells.

    Science.gov (United States)

    Liu, Elizabeth; Van Grol, Jennifer; Subauste, Carlos S

    2015-04-01

    The autophagy proteins (Atg) modulate not only innate but also adaptive immunity against pathogens. We examined the role of dendritic cell Atg5 and Atg7 in the production of IL-2 and IFN-γ by Toxoplasma gondii-reactive CD4(+) T cells. T. gondii-reactive mouse CD4(+) T cells exhibited unimpaired production of IL-2 and IFN-γ when stimulated with Atg7-deficient mouse dendritic cells that were infected with T. gondii or pulsed with T. gondii lysate antigens. In marked contrast, dendritic cells deficient in Atg5 induced diminished CD4(+) T cell production of IL-2 and IFN-γ. This defect was not accompanied by changes in costimulatory ligand expression on dendritic cells or impaired production of IL-12 p70, IL-1β or TNF-α. Knockdown of Irg6a in dendritic cells did not affect CD4(+) T cell cytokine production. These results indicate that Atg5 and Atg7 in dendritic cells play differential roles in the modulation of IL-2 and IFN-γ production by T. gondii-reactive CD4(+) T cells.

  2. Gallic Acid Is the Major Active Component of Cortex Moutan in Inhibiting Immune Maturation of Human Monocyte-Derived Dendritic Cells

    Directory of Open Access Journals (Sweden)

    Ben Chung Lap Chan

    2015-09-01

    Full Text Available Atopic dermatitis (AD is a widely prevalent and chronically relapsing inflammatory skin disease. Penta Herbs Formula (PHF is efficacious in improving the quality of life and reducing topical corticosteroid used in children with AD and one of the active herbs it contains is Cortex Moutan. Recent studies showed that altered functions of dendritic cells (DC were observed in atopic individuals, suggesting that DC might play a major role in the generation and maintenance of inflammation by their production of pro-inflammatory cytokines. Hence, the aims of the present study were to identify the major active component(s of Cortex Moutan, which might inhibit DC functions and to investigate their possible interactions with conventional corticosteroid on inhibiting the development of DC from monocytes. Monocyte-derived dendritic cells (moDC culture model coupled with the high-speed counter-current chromatography (HSCCC, high pressure liquid chromatography (HPLC and Liquid Chromatography-Mass Spectrometry (LCMS analyses were used. Gallic acid was the major active component from Cortex Moutan which could dose dependently inhibit interleukin (IL-12 p40 and the functional cluster of differentiation (CD surface markers CD40, CD80, CD83 and CD86 expression from cytokine cocktail-activated moDC. Gallic acid could also lower the concentration of hydrocortisone required to inhibit the activation of DC.

  3. Gallic Acid Is the Major Active Component of Cortex Moutan in Inhibiting Immune Maturation of Human Monocyte-Derived Dendritic Cells.

    Science.gov (United States)

    Chan, Ben Chung Lap; Li, Long Fei; Hu, Shui Qing; Wat, Elaine; Wong, Eric Chun Wai; Zhang, Vanilla Xin; Lau, Clara Bik San; Wong, Chun Kwok; Hon, Kam Lun Ellis; Hui, Patrick Chi Leung; Leung, Ping Chung

    2015-09-10

    Atopic dermatitis (AD) is a widely prevalent and chronically relapsing inflammatory skin disease. Penta Herbs Formula (PHF) is efficacious in improving the quality of life and reducing topical corticosteroid used in children with AD and one of the active herbs it contains is Cortex Moutan. Recent studies showed that altered functions of dendritic cells (DC) were observed in atopic individuals, suggesting that DC might play a major role in the generation and maintenance of inflammation by their production of pro-inflammatory cytokines. Hence, the aims of the present study were to identify the major active component(s) of Cortex Moutan, which might inhibit DC functions and to investigate their possible interactions with conventional corticosteroid on inhibiting the development of DC from monocytes. Monocyte-derived dendritic cells (moDC) culture model coupled with the high-speed counter-current chromatography (HSCCC), high pressure liquid chromatography (HPLC) and Liquid Chromatography-Mass Spectrometry (LCMS) analyses were used. Gallic acid was the major active component from Cortex Moutan which could dose dependently inhibit interleukin (IL)-12 p40 and the functional cluster of differentiation (CD) surface markers CD40, CD80, CD83 and CD86 expression from cytokine cocktail-activated moDC. Gallic acid could also lower the concentration of hydrocortisone required to inhibit the activation of DC.

  4. H9N2 Avian Influenza Virus Protein PB1 Enhances the Immune Responses of Bone Marrow-Derived Dendritic Cells by Down-Regulating miR375

    Science.gov (United States)

    Lin, Jian; Xia, Jing; Tu, Chong Z.; Zhang, Ke Y.; Zeng, Yan; Yang, Qian

    2017-01-01

    Polymerase basic protein 1 (PB1), the catalytic core of the influenza A virus RNA polymerase complex, is essential for viral transcription and replication. Dendritic cells (DCs) possess important antigen presenting ability and a crucial role in recognizing and clearing virus. MicroRNA (miRNA) influence the development of DCs and their ability to present antigens as well as the ability of avian influenza virus (AIV) to infect host cells and replicate. Here, we studied the molecular mechanism underlying the miRNA-mediated regulation of immune function in mouse DCs. We first screened for and verified the induction of miRNAs in DCs after PB1 transfection. Results showed that the viral protein PB1 down-regulated the expression of miR375, miR146, miR339, and miR679 in DCs, consistent with the results of H9N2 virus treatment; however, the expression of miR222 and miR499, also reduced in the presence of PB1, was in contrast to the results of H9N2 virus treatment. Our results suggest that PB1 enhanced the ability of DCs to present antigens, activate lymphocytes, and secrete cytokines, while miR375 over-expression repressed activation of DC maturation. Nevertheless, PB1 could not promote DC maturation once miR375 was inhibited. Finally, we revealed that PB1 inhibited the P-Jnk/Jnk signaling pathway, but activated the p-Erk/Erk signaling pathway. While inhibition of miR375 -activated the p-Erk/Erk and p-p38/p38 signaling pathway, but repressed the P-Jnk/Jnk signaling pathway. Taken together, results of our studies shed new light on the roles and mechanisms of PB1 and miR375 in regulating DC function and suggest new strategies for combating AIV.

  5. Serine deprivation enhances antineoplastic activity of biguanides.

    Science.gov (United States)

    Gravel, Simon-Pierre; Hulea, Laura; Toban, Nader; Birman, Elena; Blouin, Marie-José; Zakikhani, Mahvash; Zhao, Yunhua; Topisirovic, Ivan; St-Pierre, Julie; Pollak, Michael

    2014-12-15

    Metformin, a biguanide widely used in the treatment of type II diabetes, clearly exhibits antineoplastic activity in experimental models and has been reported to reduce cancer incidence in diabetics. There are ongoing clinical trials to evaluate its antitumor properties, which may relate to its fundamental activity as an inhibitor of oxidative phosphorylation. Here, we show that serine withdrawal increases the antineoplastic effects of phenformin (a potent biguanide structurally related to metformin). Serine synthesis was not inhibited by biguanides. Instead, metabolic studies indicated a requirement for serine to allow cells to compensate for biguanide-induced decrease in oxidative phosphorylation by upregulating glycolysis. Furthermore, serine deprivation modified the impact of metformin on the relative abundance of metabolites within the citric acid cycle. In mice, a serine-deficient diet reduced serine levels in tumors and significantly enhanced the tumor growth-inhibitory actions of biguanide treatment. Our results define a dietary manipulation that can enhance the efficacy of biguanides as antineoplastic agents that target cancer cell energy metabolism.

  6. Monocyte-derived dendritic cells enhance cell proliferation and porcine circovirus type 2 replication in concanavalin A-stimulated swine peripheral blood lymphocytes in vitro.

    Science.gov (United States)

    Lin, Chun-Ming; Jeng, Chian-Ren; Hsiao, Shih-Hsuan; Lee, Yao; Tsai, Yi-Chieh; Chia, Mi-Yuan; Pang, Victor Fei

    2012-01-15

    Dendritic cells (DCs) are professional antigen presenting cells cooperating with other immune cells for the activation of innate and adaptive immune responses. The objective of the present study was to investigate the replication activity of porcine circovirus type 2 (PCV2) in DCs and/or lymphocytes during their cross talk and its possible mechanism. Two models were set, herein. Swine blood monocyte (Mo)-derived DCs (MoDCs) or peripheral blood lymphocytes (PBLs) were inoculated with PCV2 prior to their co-cultivation. Bacterial lipopolysaccharide (LPS) and concanavalin A (Con A) were used to stimulate MoDCs and PBLs, respectively. During 6 days of cultivation, a high PCV2 antigen-containing rate without detectable intranuclear signals and a slight but significant increase in the copy number of PCV2 genome were detected in PCV2-inoculated MoDCs. The presence of LPS alone or PCV2-free PBLs, however, had no effect on the location of PCV2 antigens or copy number of PCV2 genome in PCV2-inoculated MoDCs. On the contrary, active PCV2 replication occurred in Con A-stimulated PCV2-inoculated PBLs. When compared with blood Mos, MoDCs induced significantly higher cell proliferation and intensified PCV2 replication in Con A-stimulated PCV2-inoculated PBLs, for which direct contact between MoDCs and lymphocytes was required. Among the cytokines secreted by Con A-activated PBLs, interleukin (IL)-2, but not IL-4 or interferon-γ, could induce cell proliferation and PCV2 replication in PCV2-inoculated PBLs. The findings suggest that although MoDCs support only limited PCV2 replication in themselves, their accessory cell function is required for cell proliferation and PCV2 replication in PCV2-infected lymphocytes.

  7. Pattern recognition receptor signaling in human dendritic cells is enhanced by ICOS ligand and modulated by the Crohn's disease ICOSLG risk allele.

    Science.gov (United States)

    Hedl, Matija; Lahiri, Amit; Ning, Kaida; Cho, Judy H; Abraham, Clara

    2014-05-15

    Inflammatory bowel disease (IBD) is characterized by dysregulated intestinal immune homeostasis and cytokine secretion. Multiple loci are associated with IBD, but a functional explanation is missing for most. Here we found that pattern-recognition receptor (PRR)-induced cytokine secretion was diminished in human monocyte-derived dendritic cells (MDDC) from rs7282490 ICOSLG GG risk carriers. Homotypic interactions between the costimulatory molecule ICOS and the ICOS ligand on MDDCs amplified nucleotide-binding oligomerization domain 2 (NOD2)-initiated cytokine secretion. This amplification required arginine residues in the ICOSL cytoplasmic tail that recruited the adaptor protein RACK1 and the kinases PKC and JNK leading to PKC, MAPK, and NF-κB activation. MDDC from rs7282490 GG risk-carriers had reduced ICOSL expression and PRR-initiated signaling and this loss-of-function ICOSLG risk allele associated with an ileal Crohn's disease phenotype, similar to polymorphisms in NOD2. Taken together, ICOSL amplifies PRR-initiated outcomes, which might contribute to immune homeostasis.

  8. [Regulation of autophagy on dendritic cells during rat liver regeneration by IPA].

    Science.gov (United States)

    Qiwen, Wang; Wei, Jin; Cuifang, Chang; Cunshuan, Xu

    2015-03-01

    To understand the mechanism underlying autophagy in regulating dendritic cells during rat liver regeneration, we used the method of percoll density gradient centrifugation combined with immunomagnetic bead to isolate dendritic cells, the Rat Genome 230 2.0 Array to determine the expression changes of autophagy-related genes, and Ingenuity Pathway Analysis 9.0 (IPA) to determine the autophagy activities. The results indicated that LC3, BECN1, ATG7 and SQSTM1 genes had significant expression changes during rat liver regeneration. There were 593 genes related to autophagy, among which 210 genes were identified as significant. We also showed that the activity of autophagy was enhanced in the priming phase and teminal phase of liver regeneration, weakened in the proliferative stage by comparative analysis method of IPA. The autophagy-related physiological activities mainly included RNA expression, RNA transcription, cell differentiation and proliferation, involving in PPARα/RXRα activation, acute phase response signaling, TREM1 signaling, IL-6 signaling, IL-8 signaling and IL-1 signaling, whose activities were increased or decreased in liver regeneration. Cluster analysis found that P53 and AMPK signaling participated in the regulation of dendritic cells autophagy, with AMPK signaling in the priming phase of liver regeneration, and both signaling pathways in the terminal phase. We conclude that dendritic cells autophagy played an important role in initiation of the immune response in priming phase and depletion of dendritic cells in late phase during rat liver regeneration.

  9. G1-4A, a polysaccharide from Tinospora cordifolia induces peroxynitrite dependent killer dendritic cell (KDC) activity against tumor cells.

    Science.gov (United States)

    Pandey, Vipul K; Amin, Prayag J; Shankar, Bhavani S

    2014-12-01

    Dendritic cells (DC) play a central role in the development of an adaptive immune response against tumor. In addition to its role in antigen presentation, DC also possesses cytotoxic activity against tumor cells. We have earlier shown phenotypic and functional maturation of bone marrow derived dendritic cells (BMDC) by G1-4A, an arabinogalactan derived from Tinospora cordifolia. In this study, we have investigated the killer phenotype of BMDC matured in the presence of G1-4A, [mBMDC (G1-4A)] on tumor cells. We have observed several fold increase in killing of tumor cells by mBMDC (G1-4A). The tumoricidal activity was not specific to syngeneic tumors cells but could kill xenogenic tumors also. Nitric oxide released by mBMDC (G1-4A) generates peroxynitrite in tumor cells and is responsible for killing of target cells. This killing was completely abrogated by inducible nitric oxide synthase (iNOS) inhibitor 1400W and NADPH oxidase inhibitor apocyanin. The killed target cells are phagocytosed by BMDC which further activate syngeneic cytotoxic T cells. These results thus show that G1-4A treated mBMDC acquire killer phenotype along with maturation which plays an important role in activation of cytotoxic T cells.

  10. Natural IgM switches the function of LPS activated murine bone marrow dendritic cells (BMDC) to a “regulatory” DC that suppresses innate inflammation1

    OpenAIRE

    Lobo, Peter I.; Schlegel, Kailo H.; Bajwa, Amandeep; Huang, Liping; Kurmaeva, Elvira; Wang, Binru; Ye, Hong; Tedder, Thomas F.; Kinsey, Gilbert R.; Okusa, Mark D.

    2015-01-01

    We have previously shown that polyclonal natural IgM protects mice from renal IRI by inhibiting the reperfusion inflammatory response. We hypothesized that a potential mechanism involved IgM modulation of dendritic cells as we observed high IgM binding to splenic DC. To test this hypothesis, we pre-treated BMDC with polyclonal murine or human IgM prior to LPS activation and demonstrate that 0.5 × 106 IgM/LPS pretreated BMDC, when injected into WT-B6 mice, 24 hours before renal ischemia, prote...

  11. Cholinergic modulation differs between basal and apical dendritic excitation of hippocampal CA1 pyramidal cells.

    Science.gov (United States)

    Leung, L Stan; Péloquin, Pascal

    2010-08-01

    We hypothesize that endogenous cholinergic modulation of dendritic processing of hippocampal CA1 is layer specific, and it specifically enhances spike output resulting from basal as compared with the apical dendritic excitation. Laminar profiles of evoked field potentials were recorded in the CA1 area of urethane-anesthetized rats using multichannel silicon probes and analyzed as current source density. High-frequency stimulation of the pontis oralis (PnO) attenuated the midapical more than the basal or distal apical dendritic excitatory sink. Population spike (PS) and excitatory sink-PS potentiation resulting from basal dendritic excitation were facilitated, while the PS evoked by apical dendritic stimulation was attenuated by PnO stimulation. Perfusion of cholinergic agonist carbachol onto hippocampal slices in vitro also attenuated the apical more than the basal dendritic excitatory postsynaptic potentials. Excitatory sink attenuation and PS changes after PnO stimulation were blocked by systemic or local scopolamine and by intracerebroventricular (icv) M1 receptor antagonist pirenzepine but not by icv M2 receptor antagonist AFDX-116 or nicotinic antagonists. However, a hippocampal theta rhythm activated by PnO stimulation was blocked by systemic but not by local scopolamine. We conclude that endogenous acetylcholine mediates a stronger presynaptic inhibition of the midapical than basal and distal apical excitation mainly through M1 receptors.

  12. Enhancement of the priming efficacy of DNA vaccines encoding dendritic cell-targeted antigens by synergistic toll-like receptor ligands

    Directory of Open Access Journals (Sweden)

    Kornbluth Richard S

    2009-08-01

    Full Text Available Abstract Background Targeting of protein antigens to dendritic cells (DC via the DEC205 receptor enhances presentation of antigen-derived peptides on MHC-I and MHC-II molecules and, in the presence of costimulatory signals, antigen-specific immune responses. The immunogenicity and efficacy of DNA vaccination can also be enhanced by fusing the encoded antigen to single chain antibodies directed against DEC205. To further improve this strategy, we evaluated different toll-like receptor ligands (TLR and CD40 ligands (CD40L as adjuvants for DNA vaccines encoding a DEC205-single-chain antibody fused to the ovalbumin model antigen or HIV-1 Gag and assessed the priming efficacy of DNA in a DNA prime adenoviral vector boost immunization regimen. Results Mice were primed with the adjuvanted DEC-205 targeted DNA vaccines and boosted with adenoviral vectors encoding the same antigens. CD8+ T cell responses were determined after the adenoviral booster immunization, to determine how well the different DNA immunization regimens prime for the adenoviral boost. In the absence of adjuvants, targeting of DNA-encoded ovalbumin to DCs suppressed CD8+ T-cell responses after the adenoviral booster immunization. CD8+ T-cell responses to the DEC205 targeted DNA vaccines increased only slightly by adding either the TLR-9 ligand CpG, the TLR-3 ligand Poly I:C, or CD40 ligand expression plasmids. However, the combination of both TLR-ligands led to a strong enhancement of CD8+ T-cell responses compared to a non-targeted DNA vaccine. This finding was confirmed using HIV Gag as antigen. Conclusion Although DNA prime adenoviral vector boost immunizations belong to the strongest inducers of cytotoxic T cell responses in different animal models and humans, the CD8+ T cell responses can be further improved by targeting the DNA encoded antigen to DEC205 in the presence of synergistic TLR ligands CpG and Poly I:C.

  13. Phanerochaete mutants with enhanced ligninolytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Kakar, S.N.; Perez, A.; Gonzales, J.

    1993-06-01

    In addition to lignin, the white rot fungus Phanerochaete chrysosporium has the ability to degrade a wide spectrum of recalcitrant organopollutants in soils and aqueous media. Although some of the organic compounds are degraded under nonligninolytic conditions, most are degraded under ligninolytic conditions with the involvement of the extracellular enzymes, lignin peroxidases, and manganese-dependent peroxidases, which are produced as secondary metabolites triggered by conditions of nutrient starvation (e.g., nitrogen limitation). The fungus and its enzymes can thus provide alternative technologies for bioremediation, biopulping, biobleaching, and other industrial applications. The efficiency and effectiveness of the fungus can be enhanced by increasing production and secretion of the important enzymes in large quantities and as primary metabolites under enriched conditions. One way this can be achieved is through isolation of mutants that are deregulated or are hyperproducers or supersecretors of key enzymes under enriched conditions. Through ultraviolet-light and gamma-rays mutagenesis we have isolated a variety of mutants, some of which produce key enzymes of the ligninolytic system under high-nitrogen growth conditions. One of the mutants produced 272 units (U) of lignin peroxidases enzyme activity per liter after nine days under high nitrogen. The mutant and the parent strains produced up to 54 U/L and 62 U/L, respectively, of the enzyme activity under low-nitrogen growth conditions during this period. In some experiments the mutant showed 281 U/L of enzyme activity under high nitrogen after 17 days.

  14. Alternate Reading Frame Protein (F Protein) of Hepatitis C Virus: Paradoxical Effects of Activation and Apoptosis on Human Dendritic Cells Lead to Stimulation of T Cells

    Science.gov (United States)

    Samrat, Subodh Kumar; Li, Wen; Singh, Shakti; Kumar, Rakesh; Agrawal, Babita

    2014-01-01

    Hepatitis C virus (HCV) leads to chronic infection in the majority of infected individuals due to lack, failure, or inefficiency of generated adaptive immune responses. In a minority of patients, acute infection is followed by viral clearance. The immune correlates of viral clearance are not clear yet but have been extensively investigated, suggesting that multispecific and multifunctional cellular immunity is involved. The generation of cellular immunity is highly dependent upon how antigen presenting cells (APCs) process and present various viral antigens. Various structural and non-structural HCV proteins derived from the open reading frame (ORF) have been implicated in modulation of dendritic cells (DCs) and APCs. Besides the major ORF proteins, the HCV core region also encodes an alternate reading frame protein (ARFP or F), whose function in viral pathogenesis is not clear. In the current studies, we sought to determine the role of HCV-derived ARFP in modulating dendritic cells and stimulation of T cell responses. Recombinant adenovirus vectors containing F or core protein derived from HCV (genotype 1a) were prepared and used to endogenously express these proteins in dendritic cells. We made an intriguing observation that endogenous expression of F protein in human DCs leads to contrasting effects on activation and apoptosis of DCs, allowing activated DCs to efficiently internalize apoptotic DCs. These in turn result in efficient ability of DCs to process and present antigen and to prime and stimulate F protein derived peptide-specific T cells from HCV-naive individuals. Taken together, our findings suggest important aspects of F protein in modulating DC function and stimulating T cell responses in humans. PMID:24475147

  15. Alternate reading frame protein (F protein of hepatitis C virus: paradoxical effects of activation and apoptosis on human dendritic cells lead to stimulation of T cells.

    Directory of Open Access Journals (Sweden)

    Subodh Kumar Samrat

    Full Text Available Hepatitis C virus (HCV leads to chronic infection in the majority of infected individuals due to lack, failure, or inefficiency of generated adaptive immune responses. In a minority of patients, acute infection is followed by viral clearance. The immune correlates of viral clearance are not clear yet but have been extensively investigated, suggesting that multispecific and multifunctional cellular immunity is involved. The generation of cellular immunity is highly dependent upon how antigen presenting cells (APCs process and present various viral antigens. Various structural and non-structural HCV proteins derived from the open reading frame (ORF have been implicated in modulation of dendritic cells (DCs and APCs. Besides the major ORF proteins, the HCV core region also encodes an alternate reading frame protein (ARFP or F, whose function in viral pathogenesis is not clear. In the current studies, we sought to determine the role of HCV-derived ARFP in modulating dendritic cells and stimulation of T cell responses. Recombinant adenovirus vectors containing F or core protein derived from HCV (genotype 1a were prepared and used to endogenously express these proteins in dendritic cells. We made an intriguing observation that endogenous expression of F protein in human DCs leads to contrasting effects on activation and apoptosis of DCs, allowing activated DCs to efficiently internalize apoptotic DCs. These in turn result in efficient ability of DCs to process and present antigen and to prime and stimulate F protein derived peptide-specific T cells from HCV-naive individuals. Taken together, our findings suggest important aspects of F protein in modulating DC function and stimulating T cell responses in humans.

  16. Leishmania mexicana amastigotes inhibit p38 and JNK and activate PI3K/AKT: role in the inhibition of apoptosis of dendritic cells.

    Science.gov (United States)

    Vázquez-López, R; Argueta-Donohué, J; Wilkins-Rodríguez, A; Escalona-Montaño, A; Aguirre-García, M; Gutiérrez-Kobeh, L

    2015-11-01

    Leishmania mexicana is the causal agent of cutaneous leishmaniasis in Mexico. Dendritic cells (DC) are one of the host cells of Leishmania parasites. Intracellular microorganisms inhibit host cell apoptosis as a strategy to ensure their survival in infected cells. We have previously shown that Leishmania mexicana promastigotes and amastigotes inhibit camptothecin-induced apoptosis of monocyte-derived dendritic cells (moDC), but the mechanisms underlying the inhibition of apoptosis of DC by Leishmania have not been established. MAP kinases and PI3K participate in the process of apoptosis and are modulated by different species of Leishmania. As shown in this study, the infection of moDC with L. mexicana amastigotes diminished significantly the phosphorylation of the MAP kinases p38 and JNK. The inhibition of both kinases diminished significantly DNA fragmentation in moDC stimulated with camptothecin. On the other hand, L. mexicana amastigotes were able to activate the anti-apoptotic pathways PI3K and AKT. Our results indicate that L. mexicana amastigotes have the capacity to diminish MAP kinases activation and activate PI3K and AKT, which is probably one of the strategies employed by L. mexicana amastigotes to inhibit apoptosis in the infected moDC.

  17. Human dendritic cells activated via dectin-1 are efficient at priming Th17, cytotoxic CD8 T and B cell responses.

    Directory of Open Access Journals (Sweden)

    Sudhanshu Agrawal

    Full Text Available BACKGROUND: Dendritic cells capture antigens through PRRs and modulate adaptive immune responses. The type of adaptive immune T cell response generated is dependent upon the type of PRR activated by the microbes. Dectin-1 is a C-type lectin receptor present on dendritic cells. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that selective dectin-1 agonist Curdlan can activate human DCs and induce the secretion of large amounts of IL-23, IL-1β, IL-6 and low levels of IL-12p70 as determined by ELISA. The Curdlan-stimulated DCs are efficient at priming naïve CD4 cells to differentiate into Th17 and Th1 cells. Furthermore, these CD4 T cells induce differentiation of B cells to secrete IgG and IgA. In addition, Curdlan-stimulated DCs promote the expansion and differentiation of Granzyme and perforin expressing cytotoxic T lymphocyte that display high cytolytic activity against target tumor cells in vitro. CONCLUSIONS/SIGNIFICANCE: These data demonstrate that DCs stimulated through Dectin-1 can generate efficient Th, CTL and B cell responses and can therefore be used as effective mucosal and systemic adjuvants in humans.

  18. Tick salivary cystatin sialostatin L2 suppresses IFN responses in mouse dendritic cells.

    Science.gov (United States)

    Lieskovská, J; Páleníková, J; Širmarová, J; Elsterová, J; Kotsyfakis, M; Campos Chagas, A; Calvo, E; Růžek, D; Kopecký, J

    2015-02-01

    Type I interferon (IFN), mainly produced by dendritic cells (DCs), is critical in the host defence against tick-transmitted pathogens. Here, we report that salivary cysteine protease inhibitor from the hard tick Ixodes scapularis, sialostatin L2, affects IFN-β mediated immune reactions in mouse dendritic cells. Following IFN receptor ligation, the Janus activated kinases/signal transducer and activator of transcription (JAK/STAT) pathway is activated. We show that sialostatin L2 attenuates phosphorylation of STATs in spleen dendritic cells upon addition of recombinant IFN-β. LPS-stimulated dendritic cells release IFN-β which in turn leads to the induction of IFN-stimulated genes (ISG) through JAK/STAT pathway activation. The induction of two ISG, interferon regulatory factor 7 (IRF-7) and IP-10, was suppressed by sialostatin L2 in LPS-stimulated dendritic cells. Finally, the interference of sialostatin L2 with IFN action led to the enhanced replication of tick-borne encephalitis virus in DC. In summary, we present here that tick salivary cystatin negatively affects IFN-β responses which may consequently increase the pathogen load after transmission via tick saliva.

  19. Early events in axon/dendrite polarization.

    Science.gov (United States)

    Cheng, Pei-lin; Poo, Mu-ming

    2012-01-01

    Differentiation of axons and dendrites is a critical step in neuronal development. Here we review the evidence that axon/dendrite formation during neuronal polarization depends on the intrinsic cytoplasmic asymmetry inherited by the postmitotic neuron, the exposure of the neuron to extracellular chemical factors, and the action of anisotropic mechanical forces imposed by the environment. To better delineate the functions of early signals among a myriad of cellular components that were shown to influence axon/dendrite formation, we discuss their functions by distinguishing their roles as determinants, mediators, or modulators and consider selective degradation of these components as a potential mechanism for axon/dendrite polarization. Finally, we examine whether these early events of axon/dendrite formation involve local autocatalytic activation and long-range inhibition, as postulated by Alan Turing for the morphogenesis of patterned biological structure.

  20. Dendritic cells and contact dermatitis.

    Science.gov (United States)

    Sasaki, Yoshinori; Aiba, Setsuya

    2007-10-01

    Contact dermatitis is a biological response to simple chemicals in the skin. Although it is well known that allergic contact dermatitis is mediated by the immune system, it is still uncertain whether it is a kind of protective response or it is simply an unnecessary response. We have demonstrated the following: (1) haptens activate Langerhans cells in the initiation phase of murine allergic contact dermatitis in vivo, (2) haptens activate human monocyte-derived dendritic cells in vitro, (3) the activation of dendritic cells by haptens is primarily mediated by the activation of p38 mitogen-activated protein kinase (MAPK), and (4) the activation of p38 MAPK is mediated by stimulation related to an imbalance of intracellular redox. Based on these observations, we will discuss the biological significance of contact dermatitis. In addition, we will review some up-to-date findings on Langerhans cell biology.

  1. Isothermal Dendritic Growth Experiment - PVA Dendrites

    Science.gov (United States)

    1997-01-01

    The Isothermal Dendritic Growth Experiment (IDGE), flown on three Space Shuttle missions, is yielding new insights into virtually all industrially relevant metal and alloy forming operations. IDGE used transparent organic liquids that form dendrites (treelike structures) similar to those inside metal alloys. Comparing Earth-based and space-based dendrite growth velocity, tip size and shape provides a better understanding of the fundamentals of dentritic growth, including gravity's effects. Shalowgraphic images of pivalic acid (PVA) dendrites forming from the melt show the subtle but distinct effects of gravity-driven heat convection on dentritic growth. In orbit, the dendrite grows as its latent heat is liberated by heat conduction. This yields a blunt dendrite tip. On Earth, heat is carried away by both conduction and gravity-driven convection. This yields a sharper dendrite tip. In addition, under terrestrial conditions, the sidebranches growing in the direction of gravity are augmented as gravity helps carry heat out of the way of the growing sidebranches as opposed to microgravity conditions where no augmentation takes place. IDGE was developed by Rensselaer Polytechnic Institute and NASA/Glenn Research Center. Advanced follow-on experiments are being developed for flight on the International Space Station. Photo Credit: NASA/Glenn Research Center

  2. Microtubules in Dendritic Spine Development

    OpenAIRE

    2008-01-01

    It is generally believed that only the actin cytoskeleton resides in dendritic spines and controls spine morphology and plasticity. Here we report that microtubules (MTs) are present in spines and that shRNA knockdown of the MT-plus end binding protein EB3 significantly reduces spine formation. Furthermore, stabilization and inhibition of MTs by low doses of taxol and nocodazole enhance and impair spine formation elicited by BDNF, respectively. Therefore, MTs play an important role in the con...

  3. Reduction of conventional dendritic cells during Plasmodium infection is dependent on activation induced cell death by type I and II interferons.

    Science.gov (United States)

    Tamura, Takahiko; Kimura, Kazumi; Yui, Katsuyuki; Yoshida, Shigeto

    2015-12-01

    Dendritic cells (DCs) play critical roles in innate and adaptive immunity and in pathogenesis during the blood stage of malaria infection. The mechanisms underlying DC homeostasis during malaria infection are not well understood. In this study, the numbers of conventional DCs (cDCs) and plasmacytoid DCs (pDCs) in the spleens after lethal rodent malaria infection were examined, and were found to be significantly reduced. Concomitant with up-regulation of maturation-associated molecules, activation of caspase-3 was significantly increased, suggesting induction of cell death. Studies using neutralizing antibody and gene-deficient mice showed that type I and II interferons were critically involved in activation induced cell death of cDCs during malaria infection. These results demonstrate that DCs rapidly disappeared following IFN-mediated DC activation, and that homeostasis of DCs was significantly impaired during malaria infection.

  4. Differential Activation of Human Monocyte-Derived and Plasmacytoid Dendritic Cells by West Nile Virus Generated in Different Host Cells▿

    Science.gov (United States)

    Silva, Maria Carlan; Guerrero-Plata, Antonieta; Gilfoy, Felicia D.; Garofalo, Roberto P.; Mason, Peter W.

    2007-01-01

    Dendritic cells (DCs) play a central role in innate immunity and antiviral responses. In this study, we investigated the production of alpha interferon (IFN-α) and inducible chemokines by human monocyte-derived dendritic cells (mDCs) and plasmacytoid dendritic cells (pDCs) infected with West Nile virus (WNV), an emergent pathogen whose infection can lead to severe cases of encephalitis in the elderly, children, and immunocompromised individuals. Our experiments demonstrated that WNV grown in mammalian cells (WNVVero) was a potent inducer of IFN-α secretion in pDCs and, to a lesser degree, in mDCs. The ability of WNVVero to induce IFN-α in pDCs did not require viral replication and was prevented by the treatment of cells with bafilomycin A1 and chloroquine, suggesting that it was dependent on endosomal Toll-like receptor recognition. On the other hand, IFN-α production in mDCs required viral replication and was associated with the nuclear translocation of IRF3 and viral antigen expression. Strikingly, pDCs failed to produce IFN-α when stimulated with WNV grown in mosquito cells (WNVC7/10), while mDCs responded similarly to WNVVero or WNVC7/10. Moreover, the IFN-dependent chemokine IP-10 was produced in substantial amounts by pDCs in response to WNVVero but not WNVC7/10, while interleukin-8 was produced in greater amounts by mDCs infected with WNVC7/10 than in those infected with WNVVero. These findings suggest that cell-specific mechanisms of WNV recognition leading to the production of type I IFN and inflammatory chemokines by DCs may contribute to both the innate immune response and disease pathogenesis in human infections. PMID:17913823

  5. T Cell Cancer Therapy Requires CD40-CD40L Activation of Tumor Necrosis Factor and Inducible Nitric-Oxide-Synthase-Producing Dendritic Cells.

    Science.gov (United States)

    Marigo, Ilaria; Zilio, Serena; Desantis, Giacomo; Mlecnik, Bernhard; Agnellini, Andrielly H R; Ugel, Stefano; Sasso, Maria Stella; Qualls, Joseph E; Kratochvill, Franz; Zanovello, Paola; Molon, Barbara; Ries, Carola H; Runza, Valeria; Hoves, Sabine; Bilocq, Amélie M; Bindea, Gabriela; Mazza, Emilia M C; Bicciato, Silvio; Galon, Jérôme; Murray, Peter J; Bronte, Vincenzo

    2016-09-12

    Effective cancer immunotherapy requires overcoming immunosuppressive tumor microenvironments. We found that local nitric oxide (NO) production by tumor-infiltrating myeloid cells is important for adoptively transferred CD8(+) cytotoxic T cells to destroy tumors. These myeloid cells are phenotypically similar to inducible nitric oxide synthase (NOS2)- and tumor necrosis factor (TNF)-producing dendritic cells (DC), or Tip-DCs. Depletion of immunosuppressive, colony stimulating factor 1 receptor (CSF-1R)-dependent arginase 1(+) myeloid cells enhanced NO-dependent tumor killing. Tumor elimination via NOS2 required the CD40-CD40L pathway. We also uncovered a strong correlation between survival of colorectal cancer patients and NOS2, CD40, and TNF expression in their tumors. Our results identify a network of pro-tumor factors that can be targeted to boost cancer immunotherapies.

  6. A critical evaluation of the activity-regulated cytoskeleton-associated protein (Arc/Arg3.1)'s putative role in regulating dendritic plasticity, cognitive processes, and mood in animal models of depression.

    Science.gov (United States)

    Li, Yan; Pehrson, Alan L; Waller, Jessica A; Dale, Elena; Sanchez, Connie; Gulinello, Maria

    2015-01-01

    Major depressive disorder (MDD) is primarily conceptualized as a mood disorder but cognitive dysfunction is also prevalent, and may limit the daily function of MDD patients. Current theories on MDD highlight disturbances in dendritic plasticity in its pathophysiology, which could conceivably play a role in the production of both MDD-related mood and cognitive symptoms. This paper attempts to review the accumulated knowledge on the basic biology of the activity-regulated cytoskeleton-associated protein (Arc or Arg3.1), its effects on neural plasticity, and how these may be related to mood or cognitive dysfunction in animal models of MDD. On a cellular level, Arc plays an important role in modulating dendritic spine density and remodeling. Arc also has a close, bidirectional relationship with postsynaptic glutamate neurotransmission, since it is stimulated by multiple glutamatergic receptor mechanisms but also modulates α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor internalization. The effects on AMPA receptor trafficking are likely related to Arc's ability to modulate phenomena such as long-term potentiation, long-term depression, and synaptic scaling, each of which are important for maintaining proper cognitive function. Chronic stress models of MDD in animals show suppressed Arc expression in the frontal cortex but elevation in the amygdala. Interestingly, cognitive tasks depending on the frontal cortex are generally impaired by chronic stress, while those depending on the amygdala are enhanced, and antidepressant treatments stimulate cortical Arc expression with a timeline that is reminiscent of the treatment efficacy lag observed in the clinic or in preclinical models. However, pharmacological treatments that stimulate regional Arc expression do not universally improve relevant cognitive functions, and this highlights a need to further refine our understanding of Arc on a subcellular and network level.

  7. A critical evaluation of the activity-regulated cytoskeleton-associated protein (Arc/Arg3.1 ’s putative role in regulating dendritic plasticity, cognitive processes, and mood in animal models of depression.

    Directory of Open Access Journals (Sweden)

    Yan eLi

    2015-08-01

    Full Text Available Major depressive disorder (MDD is primarily conceptualized as a mood disorder but cognitive dysfunction is also prevalent, and may limit the daily function of MDD patients. Current theories on MDD highlight disturbances in dendritic plasticity in its pathophysiology, which could conceivably play a role in the production of both MDD-related mood and cognitive symptoms. This paper attempts to review the accumulated knowledge on the basic biology of the activity-regulated cytoskeleton-associated protein (Arc or Arg3.1, its effects on neural plasticity, and how these may be related to mood or cognitive dysfunction in animal models of MDD. On a cellular level, Arc is found to play an important role in modulating dendritic spine density and remodeling. Arc is also found to have a close, bidirectional relationship with postsynaptic glutamate neurotransmission, since it is stimulated by multiple glutamatergic receptor mechanisms but also modulates α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA receptor internalization. The effects on AMPA receptor trafficking are likely related to Arc’s ability to modulate phenomena such as long-term potentiation, long-term depression, and synaptic scaling, each of which are important for maintaining proper cognitive function. Animal studies of chronic stress models of MDD show suppressed Arc expression in the frontal cortex but elevation in the amygdala. Interestingly, cognitive tasks depending on the frontal cortex are generally impaired by chronic stress, while those depending on the amygdala are enhanced, and antidepressant treatments stimulate cortical Arc expression with a timeline that is reminiscent of the treatment efficacy lag observed in the clinic or in preclinical models. However, pharmacological treatments that stimulate regional Arc expression do not universally improve relevant cognitive functions, and this highlights a need to further refine our understanding of Arc on a subcellular and

  8. Enhanced fluoride sorption by mechanochemically activated kaolinites.

    Science.gov (United States)

    Meenakshi, S; Sundaram, C Sairam; Sukumar, Rugmini

    2008-05-01

    Kaolinite clay obtained from the mines was processed and studied for its fluoride sorption capacity. The surface area of the clay mineral was increased from 15.11 m(2)/g (raw) to 32.43 m(2)/g (activated) by mechanochemical activation. Batch adsorption studies were conducted to optimize various equilibrating conditions like the effect of contact time, dosage, pH for both raw and micronized kaolinites (RK and MK). The effect of other interfering anions on the defluoridation capacity (DC) of the sorbents was studied. Sorption of fluoride by the sorbents was observed over a wide pH range of 3-11. The studies revealed there is an enhanced fluoride sorption on MK. FTIR and XRD were used for the characterization of the sorbent. The surface morphology of the clay material was observed using SEM. The adsorption of fluoride was studied at three different temperatures, viz., 303, 313 and 323 K. The sorption data obtained at optimized conditions were subjected to Freundlich and Langmuir isotherms. Sorption intensity (1/n) (0.770-0.810) has been evaluated using Freundlich isotherm, whereas the values of sorption capacity Q(0) (0.609, 0.714 and 0.782 mg/g) and binding energy b (0.158, 0.145 and 0.133 L/mg) at three different temperatures have been estimated using Langmuir isotherm. Adsorption process was found to be controlled by both Freundlich and Langmuir isotherms. Thermodynamic studies revealed that the sorption of fluoride on MK is endothermic and a spontaneous process. The kinetic studies indicate that the sorption of fluoride on MK follows pseudo-first-order and intraparticle diffusion models.

  9. Enhanced fluoride sorption by mechanochemically activated kaolinites

    Energy Technology Data Exchange (ETDEWEB)

    Meenakshi, S. [Department of Chemistry, Gandhigram Rural University, Gandhigram 624302, Tamilnadu (India)], E-mail: drs_meena@rediffmail.com; Sundaram, C. Sairam [Department of Science and Humanities, Karaikal Polytechnic College, Karaikal 609609, Puducherry (India); Sukumar, Rugmini [Chemical Sciences and Technologies, Regional Research Laboratory, Trivandrum 695019, Kerala (India)

    2008-05-01

    Kaolinite clay obtained from the mines was processed and studied for its fluoride sorption capacity. The surface area of the clay mineral was increased from 15.11 m{sup 2}/g (raw) to 32.43 m{sup 2}/g (activated) by mechanochemical activation. Batch adsorption studies were conducted to optimize various equilibrating conditions like the effect of contact time, dosage, pH for both raw and micronized kaolinites (RK and MK). The effect of other interfering anions on the defluoridation capacity (DC) of the sorbents was studied. Sorption of fluoride by the sorbents was observed over a wide pH range of 3-11. The studies revealed there is an enhanced fluoride sorption on MK. FTIR and XRD were used for the characterization of the sorbent. The surface morphology of the clay material was observed using SEM. The adsorption of fluoride was studied at three different temperatures, viz., 303, 313 and 323 K. The sorption data obtained at optimized conditions were subjected to Freundlich and Langmuir isotherms. Sorption intensity (1/n) (0.770-0.810) has been evaluated using Freundlich isotherm, whereas the values of sorption capacity Q{sup 0} (0.609, 0.714 and 0.782 mg/g) and binding energy b (0.158, 0.145 and 0.133 L/mg) at three different temperatures have been estimated using Langmuir isotherm. Adsorption process was found to be controlled by both Freundlich and Langmuir isotherms. Thermodynamic studies revealed that the sorption of fluoride on MK is endothermic and a spontaneous process. The kinetic studies indicate that the sorption of fluoride on MK follows pseudo-first-order and intraparticle diffusion models.

  10. Levamisole promotes murine bone marrow derived dendritic cell activation and drives Th1 immune response in vitro and in vivo.

    Science.gov (United States)

    Fu, Yubing; Wang, Ting; Xiu, Lei; Shi, Xiaojie; Bian, Ziyao; Zhang, Yongli; Ruhan, A; Wang, Xiao

    2016-02-01

    Our lab previously found that levamisole (LMS) as an adjuvant enhanced the efficacy of vaccine against infectious pathogens. However, the cellular and molecular mechanisms remain to be defined. In this study, we showed that BALB/c bone marrow-derived DC stimulated with LMS resulted in enhanced cell-surface expression of CD80, CD86, CD40 and MHC class II, as well as enhanced production of IL-12p70, TNF-α and IL-1β. Interestingly, the LMS activated DCs were able to stimulate CD4(+) T cell proliferation and facilitated Th1 differentiation by increasing the secretion of IFN-γ in an allogeneic mixed leukocyte reaction. Furthermore, to confirm the in vitro data, we investigated the effect of LMS on antigen-specific antibody and cytokine production in BALB/c mice. Immunization with LMS plus OVA showed that anti-OVA IgG2a and IFN-γ were increased significantly compared with OVA alone in BALB/c mice. In conclusion, our results suggested that murine bone marrow-derived DC, played a crucial role in the effect of LMS on the induction of Th1 responses, which probably was due to its ability to promote DC maturation and secrete proinflammatory cytokines.

  11. Stiff substrates enhance cultured neuronal network activity.

    Science.gov (United States)

    Zhang, Quan-You; Zhang, Yan-Yan; Xie, Jing; Li, Chen-Xu; Chen, Wei-Yi; Liu, Bai-Lin; Wu, Xiao-an; Li, Shu-Na; Huo, Bo; Jiang, Lin-Hua; Zhao, Hu-Cheng

    2014-08-28

    The mechanical property of extracellular matrix and cell-supporting substrates is known to modulate neuronal growth, differentiation, extension and branching. Here we show that substrate stiffness is an important microenvironmental cue, to which mouse hippocampal neurons respond and integrate into synapse formation and transmission in cultured neuronal network. Hippocampal neurons were cultured on polydimethylsiloxane substrates fabricated to have similar surface properties but a 10-fold difference in Young's modulus. Voltage-gated Ca(2+) channel currents determined by patch-clamp recording were greater in neurons on stiff substrates than on soft substrates. Ca(2+) oscillations in cultured neuronal network monitored using time-lapse single cell imaging increased in both amplitude and frequency among neurons on stiff substrates. Consistently, synaptic connectivity recorded by paired recording was enhanced between neurons on stiff substrates. Furthermore, spontaneous excitatory postsynaptic activity became greater and more frequent in neurons on stiff substrates. Evoked excitatory transmitter release and excitatory postsynaptic currents also were heightened at synapses between neurons on stiff substrates. Taken together, our results provide compelling evidence to show that substrate stiffness is an important biophysical factor modulating synapse connectivity and transmission in cultured hippocampal neuronal network. Such information is useful in designing instructive scaffolds or supporting substrates for neural tissue engineering.

  12. Antigen transfer from exosomes to dendritic cells as an explanation for the immune enhancement seen by IgE immune complexes.

    Directory of Open Access Journals (Sweden)

    Rebecca K Martin

    Full Text Available IgE antigen complexes induce increased specific T cell proliferation and increased specific IgG production. Immediately after immunization, CD23(+ B cells capture IgE antigen complexes, transport them to the spleen where, via unknown mechanisms, dendritic cells capture the antigen and present it to T cells. CD23, the low affinity IgE receptor, binds IgE antigen complexes and internalizes them. In this study, we show that these complexes are processed onto B-cell derived exosomes (bexosomes in a CD23 dependent manner. The bexosomes carry CD23, IgE and MHC II and stimulate antigen specific T-cell proliferation in vitro. When IgE antigen complex stimulated bexosomes are incubated with dendritic cells, dendritic cells induce specific T-cell proliferation in vivo, similar to IgE antigen complexes. This suggests that bexosomes can provide the essential transfer mechanism for IgE antigen complexes from B cells to dendritic cells.

  13. Astragalus root and elderberry fruit extracts enhance the IFN-ß stimulatory effects of Lactobacillus acidophilus in murine-derived dendritic cells

    DEFF Research Database (Denmark)

    Frøkiær, Hanne; Henningsen, Louise; Metzdorff, Stine Broeng

    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. In dendritic cells, the gram-negative bacteria Escherichia coli upregulates proinflammatory c...

  14. Prolonged maturation and enhanced transduction of dendritic cells migrated from human skin explants after in situ delivery of CD40-targeted adenoviral vectors

    NARCIS (Netherlands)

    de Gruijl, TD; Luykx-de Bakker, SA; Tillman, BW; van den Eertwegh, AJM; Buter, J; Lougheed, SM; van der Bij, GJ; Safer, AM; Haisma, HJ; Curiel, DT; Scheper, RJ; Pinedo, HM; Gerritsen, WR

    2002-01-01

    Therapeutic tumor vaccination with viral vectors or naked DNA, carrying the genetic code for tumor-associated Ags, critically depends on the in vivo transduction of dendritic cells (DC). Transfection of predominantly nonprofessional APC and only small numbers of DC may hamper proper T cell activatio

  15. Broad antiviral activity of carbohydrate-binding agents against the four serotypes of dengue virus in monocyte-derived dendritic cells.

    Directory of Open Access Journals (Sweden)

    Marijke M F Alen

    Full Text Available BACKGROUND: Dendritic cells (DC, present in the skin, are the first target cells of dengue virus (DENV. Dendritic cell-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN is present on DC and recognizes N-glycosylation sites on the E-glycoprotein of DENV. Thus, the DC-SIGN/E-glycoprotein interaction can be considered as an important target for inhibitors of viral replication. We evaluated various carbohydrate-binding agents (CBAs against all four described serotypes of DENV replication in Raji/DC-SIGN(+ cells and in monocyte-derived DC (MDDC. METHODOLOGY/PRINCIPAL FINDINGS: A dose-dependent anti-DENV activity of the CBAs Hippeastrum hybrid (HHA, Galanthus nivalis (GNA and Urtica dioica (UDA, but not actinohivin (AH was observed against all four DENV serotypes as analyzed by flow cytometry making use of anti-DENV antibodies. Remarkably, the potency of the CBAs against DENV in MDDC cultures was significantly higher (up to 100-fold than in Raji/DC-SIGN(+ cells. Pradimicin-S (PRM-S, a small-size non-peptidic CBA, exerted antiviral activity in MDDC but not in Raji/DC-SIGN(+ cells. The CBAs act at an early step of DENV infection as they bind to the viral envelope of DENV and subsequently prevent virus attachment. Only weak antiviral activity of the CBAs was detected when administered after the virus attachment step. The CBAs were also able to completely prevent the cellular activation and differentiation process of MDDC induced upon DENV infection. CONCLUSIONS/SIGNIFICANCE: The CBAs exerted broad spectrum antiviral activity against the four DENV serotypes, laboratory-adapted viruses and low passage clinical isolates, evaluated in Raji/DC-SIGN(+ cells and in primary MDDC.

  16. Aberrant calcium/calmodulin-dependent protein kinase II (CaMKII) activity is associated with abnormal dendritic spine morphology in the ATRX mutant mouse brain.

    Science.gov (United States)

    Shioda, Norifumi; Beppu, Hideyuki; Fukuda, Takaichi; Li, En; Kitajima, Isao; Fukunaga, Kohji

    2011-01-05

    In humans, mutations in the gene encoding ATRX, a chromatin remodeling protein of the sucrose-nonfermenting 2 family, cause several mental retardation disorders, including α-thalassemia X-linked mental retardation syndrome. We generated ATRX mutant mice lacking exon 2 (ATRX(ΔE2) mice), a mutation that mimics exon 2 mutations seen in human patients and associated with milder forms of retardation. ATRX(ΔE2) mice exhibited abnormal dendritic spine formation in the medial prefrontal cortex (mPFC). Consistent with other mouse models of mental retardation, ATRX(ΔE2) mice exhibited longer and thinner dendritic spines compared with wild-type mice without changes in spine number. Interestingly, aberrant increased calcium/calmodulin-dependent protein kinase II (CaMKII) activity was observed in the mPFC of ATRX(ΔE2) mice. Increased CaMKII autophosphorylation and activity were associated with increased phosphorylation of the Rac1-guanine nucleotide exchange factors (GEFs) T-cell lymphoma invasion and metastasis 1 (Tiam1) and kalirin-7, known substrates of CaMKII. We confirmed increased phosphorylation of p21-activated kinases (PAKs) in mPFC extracts. Furthermore, reduced protein expression and activity of protein phosphatase 1 (PP1) was evident in the mPFC of ATRX(ΔE2) mice. In cultured cortical neurons, PP1 inhibition by okadaic acid increased CaMKII-dependent Tiam1 and kalirin-7 phosphorylation. Together, our data strongly suggest that aberrant CaMKII activation likely mediates abnormal spine formation in the mPFC. Such morphological changes plus elevated Rac1-GEF/PAK signaling seen in ATRX(ΔE2) mice may contribute to mental retardation syndromes seen in human patients.

  17. Dendritic potassium channels in hippocampal pyramidal neurons.

    Science.gov (United States)

    Johnston, D; Hoffman, D A; Magee, J C; Poolos, N P; Watanabe, S; Colbert, C M; Migliore, M

    2000-05-15

    Potassium channels located in the dendrites of hippocampal CA1 pyramidal neurons control the shape and amplitude of back-propagating action potentials, the amplitude of excitatory postsynaptic potentials and dendritic excitability. Non-uniform gradients in the distribution of potassium channels in the dendrites make the dendritic electrical properties markedly different from those found in the soma. For example, the influence of a fast, calcium-dependent potassium current on action potential repolarization is progressively reduced in the first 150 micrometer of the apical dendrites, so that action potentials recorded farther than 200 micrometer from the soma have no fast after-hyperpolarization and are wider than those in the soma. The peak amplitude of back-propagating action potentials is also progressively reduced in the dendrites because of the increasing density of a transient potassium channel with distance from the soma. The activation of this channel can be reduced by the activity of a number of protein kinases as well as by prior depolarization. The depolarization from excitatory postsynaptic potentials (EPSPs) can inactivate these A-type K+ channels and thus lead to an increase in the amplitude of dendritic action potentials, provided the EPSP and the action potentials occur within the appropriate time window. This time window could be in the order of 15 ms and may play a role in long-term potentiation induced by pairing EPSPs and back-propagating action potentials.

  18. Inducible expression of endomorphins in murine dendritic cells.

    Science.gov (United States)

    Yang, Xiaohuai; Xia, Hui; Chen, Yong; Liu, Xiaofen; Zhou, Cheng; Gao, Qin; Li, Zhenghong

    2012-12-15

    Bone marrow precursor cells were extracted from C57BL/6J mice aged 7-8 weeks, and dendritic cells were purified using anti-CD11c (a specific marker for dendritic cells) antibody-coated magnetic beads. Immunofluorescence staining revealed that the expression levels of endomorphin-1 and endomorphin-2 were upregulated in dendritic cells activated by lipopolysaccharide. An enzyme immunoassay showed that lipopolysaccharide and other Toll-like receptor ligands promoted the secretion of endomorphin-1 and endomorphin-2 from activated dendritic cells. [(3)H]-thymidine incorporation demonstrated that endomorphin-1 and endomorphin-2 both inhibited the proliferation of T lymphocyte induced by activated dendritic cells. Furthermore, this immunosuppressive effect was blocked by CTOP, a specific antagonist of µ-opioid receptors. Our experimental findings indicate that activated dendritic cells can induce the expression and secretion of endomorphins, and that endomorphins suppress T lymphocyte proliferation through activation of µ-opioid receptors.

  19. Inducible expression of endomorphins in murine dendritic cells

    Institute of Scientific and Technical Information of China (English)

    Xiaohuai Yang; Hui Xia; Yong Chen; Xiaofen Liu; Cheng Zhou; Qin Gao; Zhenghong Li

    2012-01-01

    Bone marrow precursor cells were extracted from C57BL/6J mice aged 7–8 weeks, and dendritic cells were purified using anti-CD11c (a specific marker for dendritic cells) antibody-coated magnetic beads. Immunofluorescence staining revealed that the expression levels of endomorphin-1 and endomorphin-2 were upregulated in dendritic cells activated by lipopolysaccharide. An enzyme immunoassay showed that lipopolysaccharide and other Toll-like receptor ligands promoted the secretion of endomorphin-1 and endomorphin-2 from activated dendritic cells. [3H]-thymidine incorporation demonstrated that endomorphin-1 and endomorphin-2 both inhibited the proliferation of T lymphocyte induced by activated dendritic cells. Furthermore, this immunosuppressive effect was blocked by CTOP, a specific antagonist of μ-opioid receptors. Our experimental findings indicate that activated dendritic cells can induce the expression and secretion of endomorphins, and that endomorphins suppress T lymphocyte proliferation through activation of μ-opioid receptors.

  20. Peroxisome proliferator-activated receptor α agonist attenuates oxidized-low density lipoprotein induced immune maturation of human monocyte-derived dendritic cells

    Institute of Scientific and Technical Information of China (English)

    SHI Hong-yu; CAO Xue-tao; GE Jun-bo; FANG Wei-yi; YAO Kang; SUN Ai-jun; HUANG Rong-chong; JIA Qing-zhe; WANG Ke-qiang; ZOU Yun-zeng

    2008-01-01

    @@ Accumulating evidence suggests that the Th1 immune response induced by various antigens such as oxidized low density lipoprotein (ox-LDL) and heat shock proteins (HSPs) play a key role in the process of atherosclerosis.1 Dendritic cells (DCs) are the most potent antigen-presenting cells (APCs) in the body with the unique ability to initiate a primary immune response to certain antigens by the activation of "naive" T cells.2 The maturation of DC with the upregulation of costimulatory molecules such as CD83,CD40,CD86,and major histocompatibility complex (MHC) class molecules such as human leukocyte antigen (HLA)-DR,is required for DC to activate T cells.

  1. Free dendritic growth

    Science.gov (United States)

    Glicksman, M. E.

    1984-01-01

    Free dendritic growth refers to the unconstrained development of crystals within a supercooled melt, which is the classical 'dendrite problem'. Great strides have been taken in recent years in both the theoretical understanding of dendritic growth and its experimental status. The development of this field will be sketched, showing that transport theory and interfacial thermodynamics (capillarity theory) were sufficient ingredients to develop a truly predictive model of dendrite formation. The convenient, but incorrect, notion of 'maximum velocity' was used for many years to estimate the behavior of dendritic transformations until supplanted by modern dynamic stability theory. The proper combinations of transport theory and morphological stability seem to able to predict the salient aspects of dendritic growth, especially in the neighborhood of the tip. The overall development of cast microstructures, such as equiaxed zone formation, rapidly solidified microstructures, etc., also seems to contain additional non-deterministic features which lie outside the current theories discussed here.

  2. The Current Immune Function of Hepatic Dendritic Cells

    Institute of Scientific and Technical Information of China (English)

    Willy Hsu; Shang-An Shu; Eric Gershwin; Zhe-Xiong Lian

    2007-01-01

    While only a small percentage of the liver as dendritic cells, they play a major role in the regulation of liver immunity. Four major types of dendritic cell subsets include myeloid CD8α-B220-, lymphoid CD8α+B220-,plasmacytoid CD8α-B220+, and natural killer dendritic cell with CD8α-B220-NK1.1+ phenotype. Although these subsets have slightly different characteristics, they are all poor na(i)ve T cell stimulators. In exchange for their reduced capacity for allostimulation, hepatic DCs are equipped with an enhanced ability to secrete cytokines in response to TLR stimulation. In addition, they have increased level of phagocytosis. Both of these traits suggest hepatic DC as part of the innate immune system. With such a high rate of exposure to the dietary and commensal antigens, it is important for the hepatic DCs to have an enhanced innate response while maintaining a tolerogenic state to avoid chronic inflammation. Only upon secondary infectivity does the hepatic DC activate memory T cells for rapid eradication of recurring pathogen. On the other hand, overly tolerogenic characteristics of hepatic DC may be responsible for the increase prevalence of autoimmunity or liver malignancies.

  3. Dengue virus activates membrane TRAIL relocalization and IFN-α production by human plasmacytoid dendritic cells in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Mariana Gandini

    Full Text Available BACKGROUND: Dengue displays a broad spectrum of clinical manifestations that may vary from asymptomatic to severe and even fatal features. Plasma leakage/hemorrhages can be caused by a cytokine storm induced by monocytes and dendritic cells during dengue virus (DENV replication. Plasmacytoid dendritic cells (pDCs are innate immune cells and in response to virus exposure secrete IFN-α and express membrane TRAIL (mTRAIL. We aimed to characterize pDC activation in dengue patients and their function under DENV-2 stimulation in vitro. METHODS FINDINGS: Flow cytometry analysis (FCA revealed that pDCs of mild dengue patients exhibit significantly higher frequencies of mTRAIL compared to severe cases or healthy controls. Plasma levels of IFN-α and soluble TRAIL are increased in mild compared to severe dengue patients, positively correlating with pDC activation. FCA experiments showed that in vitro exposure to DENV-2 induced mTRAIL expression on pDC. Furthermore, three dimension microscopy highlighted that TRAIL was relocalized from intracellular compartment to plasma membrane. Chloroquine treatment inhibited DENV-2-induced mTRAIL relocalization and IFN-α production by pDC. Endosomal viral degradation blockade by chloroquine allowed viral antigens detection inside pDCs. All those data are in favor of endocytosis pathway activation by DENV-2 in pDC. Coculture of pDC/DENV-2-infected monocytes revealed a dramatic decrease of antigen detection by FCA. This viral antigens reduction in monocytes was also observed after exogenous IFN-α treatment. Thus, pDC effect on viral load reduction was mainly dependent on IFN-α production. CONCLUSIONS: This investigation characterizes, during DENV-2 infection, activation of pDCs in vivo and their antiviral role in vitro. Thus, we propose TRAIL-expressing pDCs may have an important role in the outcome of disease.

  4. Synaptic Control of Secretory Trafficking in Dendrites

    Directory of Open Access Journals (Sweden)

    Cyril Hanus

    2014-06-01

    Full Text Available Localized signaling in neuronal dendrites requires tight spatial control of membrane composition. Upon initial synthesis, nascent secretory cargo in dendrites exits the endoplasmic reticulum (ER from local zones of ER complexity that are spatially coupled to post-ER compartments. Although newly synthesized membrane proteins can be processed locally, the mechanisms that control the spatial range of secretory cargo transport in dendritic segments are unknown. Here, we monitored the dynamics of nascent membrane proteins in dendritic post-ER compartments under regimes of low or increased neuronal activity. In response to activity blockade, post-ER carriers are highly mobile and are transported over long distances. Conversely, increasing synaptic activity dramatically restricts the spatial scale of post-ER trafficking along dendrites. This activity-induced confinement of secretory cargo requires site-specific phosphorylation of the kinesin motor KIF17 by Ca2+/calmodulin-dependent protein kinases (CaMK. Thus, the length scales of early secretory trafficking in dendrites are tuned by activity-dependent regulation of microtubule-dependent transport.

  5. Dendritic polyurea polymers.

    Science.gov (United States)

    Tuerp, David; Bruchmann, Bernd

    2015-01-01

    Dendritic polymers, subsuming dendrimers as well as hyperbranched or highly branched polymers are well established in the field of polymer chemistry. This review article focuses on urea based dendritic polymers and summarizes their synthetic routes through both isocyanate and isocyanate-free processes. Furthermore, this article highlights applications where dendritic polyureas show their specific chemical and physical potential. For these purposes scientific publications as well as patent literature are investigated to generate a comprehensive overview on this topic.

  6. Asymmetry in signal propagation between the soma and dendrites plays a key role in determining dendritic excitability in motoneurons.

    Science.gov (United States)

    Kim, Hojeong; Jones, Kelvin E; Heckman, C J

    2014-01-01

    It is widely recognized that propagation of electrophysiological signals between the soma and dendrites of neurons differs depending on direction, i.e. it is asymmetric. How this asymmetry influences the activation of voltage-gated dendritic channels, and consequent neuronal behavior, remains unclear. Based on the analysis of asymmetry in several types of motoneurons, we extended our previous methodology for reducing a fully reconstructed motoneuron model to a two-compartment representation that preserved asymmetric signal propagation. The reduced models accurately replicated the dendritic excitability and the dynamics of the anatomical model involving a persistent inward current (PIC) dispersed over the dendrites. The relationship between asymmetric signal propagation and dendritic excitability was investigated using the reduced models while varying the asymmetry in signal propagation between the soma and the dendrite with PIC density constant. We found that increases in signal attenuation from soma to dendrites increased the activation threshold of a PIC (hypo-excitability), whereas increases in signal attenuation from dendrites to soma decreased the activation threshold of a PIC (hyper-excitability). These effects were so strong that reversing the asymmetry in the soma-to-dendrite vs. dendrite-to-soma attenuation, reversed the correlation between PIC threshold and distance of this current source from the soma. We propose the tight relation of the asymmetric signal propagation to the input resistance in the dendrites as a mechanism underlying the influence of the asymmetric signal propagation on the dendritic excitability. All these results emphasize the importance of maintaining the physiological asymmetry in dendritic signaling not only for normal function of the cells but also for biophysically realistic simulations of dendritic excitability.

  7. Probing synaptic function in dendrites with calcium imaging.

    Science.gov (United States)

    Siegel, Friederike; Lohmann, Christian

    2013-04-01

    Calcium imaging has become a widely used technique to probe neuronal activity on the cellular and subcellular levels. In contrast to standard electrophysiological methods, calcium imaging resolves sub- and suprathreshold activation patterns in structures as small as fine dendritic branches and spines. This review highlights recent findings gained on the subcellular level using calcium imaging, with special emphasis on synaptic transmission and plasticity in individual spines. Since imaging allows monitoring activity across populations of synapses, it has recently been adopted to investigate how dendrites integrate information from many synapses. Future experiments, ideally carried out in vivo, will reveal how the dendritic tree integrates and computes afferent signals. For example, it is now possible to directly test the concept that dendritic inputs are clustered and that single dendrites or dendritic stretches act as independent computational units.

  8. [The Effect of Transcription on Enhancer Activity in Drosophila melanogaster].

    Science.gov (United States)

    Erokhin, M M; Davydova, A I; Lomaev, D V; Georgiev, P G; Chetverina, D A

    2016-01-01

    In higher eukaryotes, the level of gene transcription is under the control of DNA regulatory elements, such as promoter, from which transcription is initiated with the participation of RNA polymerase II and general transcription factors, as well as the enhancer, which increase the rate of transcription with the involvement of activator proteins and cofactors. It was demonstrated that enhancers are often located in the transcribed regions of the genome. We showed earlier that transcription negatively affected the activity of enhancers in Drosophila in model transgenic systems. In this study, we tested the effect of the distance between the leading promoter, enhancer, and target promoter on the inhibitory effect of transcriptions of different strengths. It was demonstrated that the negative effect of transcription remained, but weakened with increased distance between the leading promoter and enhancer and with decreased distance between the enhancer and target promoter. Thus, transcription can modulate the activity of enhancers by controlling its maximum level.

  9. Direct type I IFN but not MDA5/TLR3 activation of dendritic cells is required for maturation and metabolic shift to glycolysis after poly IC stimulation.

    Directory of Open Access Journals (Sweden)

    Austin Pantel

    2014-01-01

    Full Text Available Type I interferons (IFNs play an important role in direct antiviral defense as well as linking the innate and adaptive immune responses. On dendritic cells (DCs, IFNs facilitate their activation and contribute to CD8(+ and CD4(+ T cell priming. However, the precise molecular mechanism by which IFNs regulate maturation and immunogenicity of DCs in vivo has not been studied in depth. Here we show that, after in vivo stimulation with the TLR ligand poly IC, IFNs dominate transcriptional changes in DCs. In contrast to direct TLR3/mda5 signaling, IFNs are required for upregulation of all pathways associated with DC immunogenicity. In addition, metabolic pathways, particularly the switch from oxidative phosphorylation to glycolysis, are also regulated by IFNs and required for DC maturation. These data provide evidence for a metabolic reprogramming concomitant with DC maturation and offer a novel mechanism by which IFNs modulate DC maturation.

  10. Non-linear dendrites can tune neurons

    Directory of Open Access Journals (Sweden)

    Romain Daniel Cazé

    2014-03-01

    Full Text Available A signature of visual, auditory, and motor cortices is the presence of neurons tuned to distinct features of the environment. While neuronal tuning can be observed in most brain areas, its origin remains enigmatic, and new calcium imaging data complicate this problem. Dendritic calcium signals, in a L2/3 neuron from the mouse visual cortex, display a wide range of tunings that could be different from the neuronal tuning (Jia et al 2010. To elucidate this observation we use multi-compartmental models of increasing complexity, from a binary to a realistic biophysical model of L2/3 neuron. These models possess non-linear dendritic subunits inside which the result of multiple excitatory inputs is smaller than their arithmetic sum. While dendritic non-linear subunits are ad-hoc in the binary model, non-linearities in the realistic model come from the passive saturation of synaptic currents. Because of these non-linearities our neuron models are scatter sensitive: the somatic membrane voltage is higher when presynaptic inputs target different dendrites than when they target a single dendrite. This spatial bias in synaptic integration is, in our models, the origin of neuronal tuning. Indeed, assemblies of presynaptic inputs encode the stimulus property through an increase in correlation or activity, and only the assembly that encodes the preferred stimulus targets different dendrites. Assemblies coding for the non-preferred stimuli target single dendrites, explaining the wide range of observed tunings and the possible difference between dendritic and somatic tuning. We thus propose, in accordance with the latest experimental observations, that non-linear integration in dendrites can generate neuronal tuning independently of the coding regime.

  11. Free D-aspartate regulates neuronal dendritic morphology, synaptic plasticity, gray matter volume and brain activity in mammals.

    Science.gov (United States)

    Errico, F; Nisticò, R; Di Giorgio, A; Squillace, M; Vitucci, D; Galbusera, A; Piccinin, S; Mango, D; Fazio, L; Middei, S; Trizio, S; Mercuri, N B; Teule, M A; Centonze, D; Gozzi, A; Blasi, G; Bertolino, A; Usiello, A

    2014-01-01

    D-aspartate (D-Asp) is an atypical amino acid, which is especially abundant in the developing mammalian brain, and can bind to and activate N-methyl-D-Aspartate receptors (NMDARs). In line with its pharmacological features, we find that mice chronically treated with D-Asp show enhanced NMDAR-mediated miniature excitatory postsynaptic currents and basal cerebral blood volume in fronto-hippocampal areas. In addition, we show that both chronic administration of D-Asp and deletion of the gene coding for the catabolic enzyme D-aspartate oxidase (DDO) trigger plastic modifications of neuronal cytoarchitecture in the prefrontal cortex and CA1 subfield of the hippocampus and promote a cytochalasin D-sensitive form of synaptic plasticity in adult mouse brains. To translate these findings in humans and consistent with the experiments using Ddo gene targeting in animals, we performed a hierarchical stepwise translational genetic approach. Specifically, we investigated the association of variation in the gene coding for DDO with complex human prefrontal phenotypes. We demonstrate that genetic variation predicting reduced expression of DDO in postmortem human prefrontal cortex is mapped on greater prefrontal gray matter and activity during working memory as measured with MRI. In conclusion our results identify novel NMDAR-dependent effects of D-Asp on plasticity and physiology in rodents, which also map to prefrontal phenotypes in humans.

  12. Electrodeposition of Au/Ag bimetallic dendrites assisted by Faradaic AC-electroosmosis flow

    Directory of Open Access Journals (Sweden)

    Jianlong Ji

    2014-03-01

    Full Text Available Au/Ag bimetallic dendrites were synthesized successfully from the corresponding aqueous solution via the AC electrodeposition method. Both of the morphologies and compositions could be tuned by the electrolyte concentration and AC frequency. The prepared bimetallic dendrites were characterized by scanning electron microscopy (SEM, energy dispersive X-ray spectrometer (EDS, transmission electron microscopy (TEM and UV–vis spectroscopy. The underlying dendrite growth mechanism was then proposed in the context of the Directed Electrochemical Nanowires Assembly (DENA models. Owing to the unscreened voltage dropping in the electrolyte bulk, electromigration dominates the species flux process, and cations tend to accumulate in areas with strong electric field intensity, such as electrode edges. Moreover, Faradaic AC-electro-osmosis (ACEO flow could increase the effective diffusion layer thickness in these areas during the electrochemical reaction, and leads to dendrite growth. Further Micro-Raman observations illustrated that the Au/Ag bimetallic dendrites exhibited pronounced surface-enhanced Raman scattering (SERS activity, using 4-mercaptopyridine (4-MP as model molecules.

  13. Electrodeposition of Au/Ag bimetallic dendrites assisted by Faradaic AC-electroosmosis flow

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Jianlong; Li, Pengwei; Sang, Shengbo, E-mail: sbsang@tyut.edu.cn; Zhang, Wendong, E-mail: wdzhang@tyut.edu.cn; Li, Gang; Hu, Jie [Micro and Nano-system Research Centre, College of Information Engineering, Taiyuan University of Technology, 030024, Taiyuan (China); Zhou, Zhaoying, E-mail: zhouzy@mail.tsinghua.edu.cn; Yang, Xing; Dong, Hualai [MEMS Laboratory, Department of Precision Instruments, Tsinghua University, 100084, Beijing (China)

    2014-03-15

    Au/Ag bimetallic dendrites were synthesized successfully from the corresponding aqueous solution via the AC electrodeposition method. Both of the morphologies and compositions could be tuned by the electrolyte concentration and AC frequency. The prepared bimetallic dendrites were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM) and UV–vis spectroscopy. The underlying dendrite growth mechanism was then proposed in the context of the Directed Electrochemical Nanowires Assembly (DENA) models. Owing to the unscreened voltage dropping in the electrolyte bulk, electromigration dominates the species flux process, and cations tend to accumulate in areas with strong electric field intensity, such as electrode edges. Moreover, Faradaic AC-electro-osmosis (ACEO) flow could increase the effective diffusion layer thickness in these areas during the electrochemical reaction, and leads to dendrite growth. Further Micro-Raman observations illustrated that the Au/Ag bimetallic dendrites exhibited pronounced surface-enhanced Raman scattering (SERS) activity, using 4-mercaptopyridine (4-MP) as model molecules.

  14. Electrodeposition of Au/Ag bimetallic dendrites assisted by Faradaic AC-electroosmosis flow

    Science.gov (United States)

    Ji, Jianlong; Li, Pengwei; Sang, Shengbo; Zhang, Wendong; Zhou, Zhaoying; Yang, Xing; Dong, Hualai; Li, Gang; Hu, Jie

    2014-03-01

    Au/Ag bimetallic dendrites were synthesized successfully from the corresponding aqueous solution via the AC electrodeposition method. Both of the morphologies and compositions could be tuned by the electrolyte concentration and AC frequency. The prepared bimetallic dendrites were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM) and UV-vis spectroscopy. The underlying dendrite growth mechanism was then proposed in the context of the Directed Electrochemical Nanowires Assembly (DENA) models. Owing to the unscreened voltage dropping in the electrolyte bulk, electromigration dominates the species flux process, and cations tend to accumulate in areas with strong electric field intensity, such as electrode edges. Moreover, Faradaic AC-electro-osmosis (ACEO) flow could increase the effective diffusion layer thickness in these areas during the electrochemical reaction, and leads to dendrite growth. Further Micro-Raman observations illustrated that the Au/Ag bimetallic dendrites exhibited pronounced surface-enhanced Raman scattering (SERS) activity, using 4-mercaptopyridine (4-MP) as model molecules.

  15. Enhanced Capacitive Characteristics of Activated Carbon by Secondary Activation

    Institute of Scientific and Technical Information of China (English)

    YANG Hui; LU Tian-hong; Yoshio Masaki

    2004-01-01

    The effect of the improvement of commercial activated carbon(AC) on its specific capacitance and high rate capability of double layer(dl) charging/discharging process has been studied. The improvement of AC was carried out via a secondary activation under steam in the presence of catalyst NiCl2, and the suitable condition was found to be a heat treatment at about 875 ℃ for 1 h. Under those conditions, the discharge specific capacitance of the improved AC increases up to 53.67 F/g, showing an increase of about 25% as compared with that of as-received AC. The good rectangular-shaped voltammograms and A.C. impedance spectra prove that the high rate capability of the capacitor made of the improved AC is enhanced significantly. The capacitance resistance(RC) time constant of the capacitor containing the improved AC is 1.74 s, which is much lower than that of the one containing as-received AC(an RC value of 4. 73 s). It is noted that both kinds of AC samples show a similar specific surface area and pore size distribution, but some changes have taken place in the carbon surface groups, especially a decrease in the concentration of surface carbonyl groups after the improvement, which have been verified by means of X-photoelectron spectroscopy. Accordingly, it is suggested that the decrease in the concentration of surface carbonyl groups for the improved AC is beneficial to the organic electrolyte ion penetrating into the pores, thus leading to the increase in both the specific capacitance and high rate capability of the supercapacitor.

  16. Activation-induced force enhancement in human adductor pollicis.

    Science.gov (United States)

    Oskouei, Ali E; Herzog, Walter

    2009-10-01

    It has been known for a long time that the steady-state isometric force after muscle stretch is bigger than the corresponding force obtained in a purely isometric contraction for electrically stimulated and maximal voluntary contractions (MVC). Recent studies using sub-maximal voluntary contractions showed that force enhancement only occurred in a sub-group of subjects suggesting that force enhancement for sub-maximal voluntary contractions has properties different from those of electrically-induced and maximal voluntary contractions. Specifically, force enhancement for sub-maximal voluntary contractions may contain an activation-dependent component that is independent of muscle stretching. To address this hypothesis, we tested for force enhancement using (i) sub-maximal electrically-induced contractions and stretch and (ii) using various activation levels preceding an isometric reference contraction at 30% of MVC (no stretch). All tests were performed on human adductor pollicis muscles. Force enhancement following stretching was found for all subjects (n=10) and all activation levels (10%, 30%, and 60% of MVC) for electrically-induced contractions. In contrast, force enhancement at 30% of MVC, preceded by 6s of 10%, 60%, and 100% of MVC was only found in a sub-set of the subjects and only for the 60% and 100% conditions. This result suggests that there is an activation-dependent force enhancement for some subjects for sub-maximal voluntary contractions. This activation-dependent force enhancement was always smaller than the stretch-induced force enhancement obtained at the corresponding activation levels. Active muscle stretching increased the force enhancement in all subjects, independent whether they showed activation dependence or not. It appears that post-activation potentiation, and the associated phosphorylation of the myosin light chains, might account for the stretch-independent force enhancement observed here.

  17. Artificial Dendritic Cells: Multi-faceted Perspectives

    CERN Document Server

    Greensmith, Julie

    2009-01-01

    Dendritic cells are the crime scene investigators of the human immune system. Their function is to correlate potentially anomalous invading entities with observed damage to the body. The detection of such invaders by dendritic cells results in the activation of the adaptive immune system, eventually leading to the removal of the invader from the host body. This mechanism has provided inspiration for the development of a novel bio-inspired algorithm, the Dendritic Cell Algorithm. This algorithm processes information at multiple levels of resolution, resulting in the creation of information granules of variable structure. In this chapter we examine the multi-faceted nature of immunology and how research in this field has shaped the function of the resulting Dendritic Cell Algorithm. A brief overview of the algorithm is given in combination with the details of the processes used for its development. The chapter is concluded with a discussion of the parallels between our understanding of the human immune system a...

  18. CD4(+) T-cell activation is differentially modulated by bacteria-primed dendritic cells, but is generally down-regulated by n-3 polyunsaturated fatty acids.

    Science.gov (United States)

    Brix, Susanne; Lund, Pia; Kjaer, Tanja M R; Straarup, Ellen M; Hellgren, Lars I; Frøkiaer, Hanne

    2010-03-01

    Appropriate activation of CD4(+) T cells is fundamental for efficient initiation and progression of acquired immune responses. Here, we showed that CD4(+) T-cell activation is dependent on changes in membrane n-3 polyunsaturated fatty acids (PUFAs) and is dynamically regulated by the type of signals provided by dendritic cells (DCs). Upon interaction with DCs primed by different concentrations and species of gut bacteria, CD4(+) T cells were activated according to the type of DC stimulus. The levels of CD80 were found to correlate to the levels of expression of CD28 and to the proliferation of CD4(+) T cells, while the presence of CD40 and CD86 on DCs inversely affected inducible costimulator (ICOS) and cytotoxic T-lymphocyte antigen-4 (CTLA-4) levels in CD4(+) T cells. For all DC stimuli, cells high in n-3 PUFAs showed reduced ability to respond to CD28 stimulation, to proliferate, and to express ICOS and CTLA-4. Diminished T-cell receptor (TCR) and CD28 signalling was found to be responsible for n-3 PUFA effects. Thus, the dietary fatty acid composition influences the overall level of CD4(+) T-cell activation induced by DCs, while the priming effect of the DC stimuli modulates CD80, CD86 and CD40 levels, thereby affecting and shaping activation of acquired immunity by differential regulation of proliferation and costimulatory molecule expression in CD4(+) T cells.

  19. Rabies virus infection induces type I interferon production in an IPS-1 dependent manner while dendritic cell activation relies on IFNAR signaling.

    Science.gov (United States)

    Faul, Elizabeth J; Wanjalla, Celestine N; Suthar, Mehul S; Gale, Michael; Wirblich, Christoph; Schnell, Matthias J

    2010-07-22

    As with many viruses, rabies virus (RABV) infection induces type I interferon (IFN) production within the infected host cells. However, RABV has evolved mechanisms by which to inhibit IFN production in order to sustain infection. Here we show that RABV infection of dendritic cells (DC) induces potent type I IFN production and DC activation. Although DCs are infected by RABV, the viral replication is highly suppressed in DCs, rendering the infection non-productive. We exploited this finding in bone marrow derived DCs (BMDC) in order to differentiate which pattern recognition receptor(s) (PRR) is responsible for inducing type I IFN following infection with RABV. Our results indicate that BMDC activation and type I IFN production following a RABV infection is independent of TLR signaling. However, IPS-1 is essential for both BMDC activation and IFN production. Interestingly, we see that the BMDC activation is primarily due to signaling through the IFNAR and only marginally induced by the initial infection. To further identify the receptor recognizing RABV infection, we next analyzed BMDC from Mda-5-/- and RIG-I-/- mice. In the absence of either receptor, there is a significant decrease in BMDC activation at 12h post infection. However, only RIG-I-/- cells exhibit a delay in type I IFN production. In order to determine the role that IPS-1 plays in vivo, we infected mice with pathogenic RABV. We see that IPS-1-/- mice are more susceptible to infection than IPS-1+/+ mice and have a significantly increased incident of limb paralysis.

  20. Triggering of dendritic cell apoptosis by xanthohumol.

    Science.gov (United States)

    Xuan, Nguyen Thi; Shumilina, Ekaterina; Gulbins, Erich; Gu, Shuchen; Götz, Friedrich; Lang, Florian

    2010-07-01

    Xanthohumol, a flavonoid from beer with anticancer activity is known to trigger apoptosis in a variety of tumor cells. Xanthohumol further has anti-inflammatory activity. However, little is known about the effect of xanthohumol on survival and function of immune cells. The present study thus addressed the effect of xanthohumol on dendritic cells (DCs), key players in the regulation of innate and adaptive immunity. To this end, mouse bone marrow-derived DCs were treated with xanthohumol with subsequent assessment of enzymatic activity of acid sphingomyelinase (Asm), ceramide formation determined with anti-ceramide antibodies in FACS and immunohistochemical analysis, caspase activity utilizing FITC conjugated anti-active caspase 8 or caspase 3 antibodies in FACS and by Western blotting, DNA fragmentation by determining the percentage of cells in the sub-G1 phase and cell membrane scrambling by annexin V binding in FACS analysis. As a result, xanthohumol stimulated Asm, enhanced ceramide formation, activated caspases 8 and 3, triggered DNA fragmentation and led to cell membrane scrambling, all effects virtually absent in DCs from gene targeted mice lacking functional Asm or in wild-type cells treated with sphingomyelinase inhibitor amitriptyline. In conclusion, xanthohumol stimulated Asm leading to caspase activation and apoptosis of bone marrow-derived DCs.

  1. Influence of low dose irradiation on differentiation, maturation and T-cell activation of human dendritic cells

    Energy Technology Data Exchange (ETDEWEB)

    Jahns, Jutta [Department of Radiotherapy and Radiation Oncology, University of Leipzig, Stephanstrasse 21, 04103 Leipzig (Germany); Anderegg, Ulf; Saalbach, Anja [Department for Dermatology, Venerology and Allergology, University of Leipzig, Johannisallee 30, 04103 Leipzig (Germany); Rosin, Britt; Patties, Ina; Glasow, Annegret [Department of Radiotherapy and Radiation Oncology, University of Leipzig, Stephanstrasse 21, 04103 Leipzig (Germany); Kamprad, Manja [Institute for Clinical Immunology and Transfusion Medicine, University of Leipzig, Johannisallee 30, 04103 Leipzig (Germany); Scholz, Markus [Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig, Haertelstr. 16-18, 04103 Leipzig (Germany); Hildebrandt, Guido, E-mail: Guido.Hildebrandt@uni-rostock.de [Department of Radiotherapy and Radiation Oncology, University of Rostock, Suedring 75, 18059 Rostock (Germany); Department of Radiotherapy and Radiation Oncology, University of Leipzig, Stephanstrasse 21, 04103 Leipzig (Germany)

    2011-05-10

    Ionizing irradiation could act directly on immune cells and may induce bystander effects mediated by soluble factors that are released by the irradiated cells. This is the first study analyzing both the direct effect of low dose ionizing radiation (LDIR) on the maturation and cytokine release of human dendritic cells (DCs) and the functional consequences for co-cultured T-cells. We showed that irradiation of DC-precursors in vitro does not influence surface marker expression or cytokine profile of immature DCs nor of mature DCs after LPS treatment. There was no difference of single dose irradiation versus fractionated irradiation protocols on the behavior of the mature DCs. Further, the low dose irradiation did not change the capacity of the DCs to stimulate T-cell proliferation. But the irradiation of the co-culture of DCs and T-cells revealed significantly lower proliferation of T-cells with higher doses. Summarizing the data from approx. 50 DC preparations there is no significant effect of low dose ionizing irradiation on the cytokine profile, surface marker expression and maturation of DCs in vitro although functional consequences cannot be excluded.

  2. Enhancer activity-based identification of functional enhancers using zebrafish embryos.

    Science.gov (United States)

    Taminato, Tomohito; Yokota, Daisuke; Araki, Soh; Ovara, Hiroki; Yamasu, Kyo; Kawamura, Akinori

    2016-08-01

    Chromatin immunoprecipitation (ChIP) against enhancer-associated marks with massive sequencing is a powerful approach to identify genome-wide distributions of putative enhancers. However, functional in vivo analysis is required to elucidate the activities of predicted enhancers. Using zebrafish embryos, we established a ChIP-Injection method that enables identification of functional enhancers based on their enhancer activities in embryos. Each reporter gene possessing the enhancer-associated genomic region enriched by ChIP was injected into zebrafish embryos to analyze the activity of putative enhancers. By using the ChIP-Injection, we identified 32 distinct putative enhancers that drove specific expression. Additionally, we generated transgenic lines that exhibit distributions of the EGFP signal as was observed in the screening. Furthermore, the expression pattern driven by the identified somite-specific enhancer resembled that of the gene acta2. The results indicate that ChIP-Injection provides an efficient approach for identification of active enhancers in a potentially wide variety of developmental tissues and stages.

  3. Activated microglia enhance neurogenesis via trypsinogen secretion.

    Science.gov (United States)

    Nikolakopoulou, Angeliki M; Dutta, Ranjan; Chen, Zhihong; Miller, Robert H; Trapp, Bruce D

    2013-05-21

    White matter neurons in multiple sclerosis brains are destroyed during demyelination and then replaced in some chronic multiple sclerosis lesions that exhibit a morphologically distinct population of activated microglia [Chang A, et al. (2008) Brain 131(Pt 9):2366-2375]. Here we investigated whether activated microglia secrete factors that promote the generation of neurons from white matter cells. Adult rat brain microglia (resting or activated with lipopolysaccharide) were isolated by flow cytometry and cocultured with neonatal rat optic nerve cells in separate but media-connected chambers. Optic nerve cells cocultured with activated microglia showed a significant increase in the number of cells of neuronal phenotype, identified by neuron-specific class III beta-tubulin (TUJ-1) labeling, compared with cultures with resting microglia. To investigate the possible source of the TUJ-1-positive cells, A2B5-positive oligodendrocyte progenitor cells and A2B5-negative cells were isolated and cocultured with resting and activated microglia. Significantly more TUJ-1-positive cells were generated from A2B5-negative cells (∼70%) than from A2B5-positive cells (~30%). Mass spectrometry analysis of microglia culture media identified protease serine 2 (PRSS2) as a factor secreted by activated, but not resting, microglia. When added to optic nerve cultures, PRSS2 significantly increased neurogenesis, whereas the serine protease inhibitor, secretory leukocyte protease inhibitor, decreased activated microglia-induced neurogenesis. Collectively our data provide evidence that activated microglia increase neurogenesis through secretion of PRSS2.

  4. Inducible expression of endomorphins in murine dendritic cells★

    OpenAIRE

    Yang, Xiaohuai; Xia, Hui; Chen, Yong; Liu, Xiaofen; Zhou, Cheng; Gao, Qin; Li, Zhenghong

    2012-01-01

    Bone marrow precursor cells were extracted from C57BL/6J mice aged 7–8 weeks, and dendritic cells were purified using anti-CD11c (a specific marker for dendritic cells) antibody-coated magnetic beads. Immunofluorescence staining revealed that the expression levels of endomorphin-1 and endomorphin-2 were upregulated in dendritic cells activated by lipopolysaccharide. An enzyme immunoassay showed that lipopolysaccharide and other Toll-like receptor ligands promoted the secretion of endomorphin-...

  5. Giardia lamblia binding immunoglobulin protein triggers maturation of dendritic cells via activation of TLR4-MyD88-p38 and ERK1/2 MAPKs.

    Science.gov (United States)

    Lee, H-Y; Kim, J; Noh, H J; Kim, H-P; Park, S-J

    2014-12-01

    Much remains unknown about the mammalian immune response to Giardia lamblia, a protozoan pathogen that causes diarrhoeal outbreaks. We fractionated protein extracts of G. lamblia trophozoites by Viva-spin centrifugation, DEAE ion exchange and gel filtration chromatography. Resultant fractions were screened for antigenic molecules by western blots analysis using anti-G. lamblia antibodies (Abs), resulting in identification of G. lamblia binding immunoglobulin protein (GlBiP). Maturation of mouse dendritic cells (DCs) in response to recombinant GlBiP (rGlBiP) was detected by increased expression of surface molecules such as CD80, CD86 and MHC class II; these mature DCs, produced pro-inflammatory cytokines (TNF-α, IL-12 and IL-6). Especially, the truncated rGlBiP containing the heat-shock protein 70 domain-induced cytokine production from mouse DCs. rGlBiP-induced DC activation was initiated by TLR4 in a MyD88-dependent way and occurred through activation of p38 and ERK1/2 MAPKs as well as increased activity of NF-κB and AP-1. Moreover, CD4(+) T cells stimulated with rGlBiP-treated DCs produced high levels of IL-2 and IFN-γ. Together, our results suggest that GlBiP contributes to maturation of DCs via activation of TLR4-MyD88-p38, ERK1/2 MAPK, NF-κB and AP-1.

  6. Remodeling of monoplanar Purkinje cell dendrites during cerebellar circuit formation.

    Directory of Open Access Journals (Sweden)

    Megumi Kaneko

    Full Text Available Dendrite arborization patterns are critical determinants of neuronal connectivity and integration. Planar and highly branched dendrites of the cerebellar Purkinje cell receive specific topographical projections from two major afferent pathways; a single climbing fiber axon from the inferior olive that extend along Purkinje dendrites, and parallel fiber axons of granule cells that contact vertically to the plane of dendrites. It has been believed that murine Purkinje cell dendrites extend in a single parasagittal plane in the molecular layer after the cell polarity is determined during the early postnatal development. By three-dimensional confocal analysis of growing Purkinje cells, we observed that mouse Purkinje cells underwent dynamic dendritic remodeling during circuit maturation in the third postnatal week. After dendrites were polarized and flattened in the early second postnatal week, dendritic arbors gradually expanded in multiple sagittal planes in the molecular layer by intensive growth and branching by the third postnatal week. Dendrites then became confined to a single plane in the fourth postnatal week. Multiplanar Purkinje cells in the third week were often associated by ectopic climbing fibers innervating nearby Purkinje cells in distinct sagittal planes. The mature monoplanar arborization was disrupted in mutant mice with abnormal Purkinje cell connectivity and motor discoordination. The dendrite remodeling was also impaired by pharmacological disruption of normal afferent activity during the second or third postnatal week. Our results suggest that the monoplanar arborization of Purkinje cells is coupled with functional development of the cerebellar circuitry.

  7. 1-MT Enhances Potency of Tumor Cell Lysate-pulsed Dendritic Cells against Pancreatic Adenocarcinoma by Downregulating the Percentage of Tregs

    Institute of Scientific and Technical Information of China (English)

    李元栋; 徐钧; 邹浩军; 王春友

    2010-01-01

    This study examined whether 1-methyl-tryptophan [1-MT,an indoleamine 2,3-dioxygenase(IDO) inhibitor] could reduce CD4+CD25+ regulatory T cells(Tregs) proliferation and improve the anti-tumor efficacy of dendritic cells(DCs) pulsed with tumor cell lysate in the mice bearing pancreatic adenocarcinoma.The models of pancreatic adenocarcinoma were established in C57BL/6 mice by subcutaneous injection of Pan02 cells.Eight mice which were subcutaneously injected with PBS served as control.The expression of IDO was...

  8. Development of Dendritic Cell System

    Institute of Scientific and Technical Information of China (English)

    LiWu; AleksandarDakic

    2004-01-01

    The dendritic cell system contains conventional dendritic cells (DCs) and plasmacytoid pre-dendritic cells (pDCs). Both DCs and pDCs are bone marrow derived calls. Although the common functions of DCs are antigen-processing and T-lymphocyte activation, they differ in surface markers, migratory patterns, and cytokine output. These differences can determine the fate of the T cells they activate. Several subsets of mature DCs have been described in both mouse and human and the developmental processes of these specialized DC subsets have been studied extensively. The original concept that all DCs were of myeloid origin was questioned by several recent studies, which demonstrated that in addition to the DCs derived from myeloid precursors, some DCs could also be efficiently generated from lymphoid-restricted precursors. Moreover, it has been shown recently that both conventional DCs and pDCs can be generated by the Fit3 expressing hemopoietic progenitors regardless of their myeloid- or lymphoid-origin. These findings suggest an early developmental flexibility of precursors for DCs and pDCs. This review summarizes some recent observations on the development of DC system in both human and mouse. Cellular & Molecular Immunology. 2004;1(2):112-118.

  9. Development of Dendritic Cell System

    Institute of Scientific and Technical Information of China (English)

    Li Wu; Aleksandar Dakic

    2004-01-01

    The dendritic cell system contains conventional dendritic cells (DCs) and plasmacytoid pre-dendritic cells (pDCs). Both DCs and pDCs are bone marrow derived cells. Although the common functions of DCs are antigen-processing and T-lymphocyte activation, they differ in surface markers, migratory patterns, and cytokine output. These differences can determine the fate of the T cells they activate. Several subsets of mature DCs have been described in both mouse and human and the developmental processes of these specialized DC subsets have been studied extensively. The original concept that all DCs were of myeloid origin was questioned by several recent studies, which demonstrated that in addition to the DCs derived from myeloid precursors,some DCs could also be efficiently generated from lymphoid-restricted precursors. Moreover, it has been shown recently that both conventional DCs and pDCs can be generated by the Flt3 expressing hemopoietic progenitors regardless of their myeloid- or lymphoid-origin. These findings suggest an early developmental flexibility of precursors for DCs and pDCs. This review summarizes some recent observations on the development of DC system in both human and mouse.

  10. Enhancing Activity for the Oxygen Evolution Reaction

    DEFF Research Database (Denmark)

    Frydendal, Rasmus; Busch, Michael; Halck, Niels Bendtsen

    2014-01-01

    Electrochemical production of hydrogen, facilitated in electrolyzers, holds great promise for energy storage and solar fuel production. A bottleneck in the process is the catalysis of the oxygen evolution reaction, involving the transfer of four electrons. The challenge is that the binding energies...... of all reaction intermediates cannot be optimized individually. However, experimental investigations have shown that drastic improvements can be realized for manganese and cobalt-based oxides if gold is added to the surface or used as substrate. We propose an explanation for these enhancements based...... that the oxygen evolution reaction overpotential decreases by 100–300 mV for manganese oxides and 100 mV for cobalt oxides....

  11. Enormous enhancement of electric field in active gold nanoshells

    Science.gov (United States)

    Jiang, Shu-Min; Wu, Da-Jian; Wu, Xue-Wei; Liu, Xiao-Jun

    2014-04-01

    The electric field enhancement properties of an active gold nanoshell with gain material inside have been investigated by using Mie theory. As the gain coefficient of the inner core increases to a critical value, a super-resonance appears in the active gold nanoshell, and enormous enhancements of the electric fields can be found near the surface of the particle. With increasing shell thickness, the critical value of the gain coefficient for the super-resonance of the active gold nanoshell first decreases and then increases, and the corresponding surface enhanced Raman scattering (SERS) enhancement factor (G factor) also first increases and then decreases. The optimized active gold nanoshell can be obtained with an extremely high SERS G factor of the order of 1019-1020. Such an optimized active gold nanoshell possesses a high-efficiency SERS effect and may be useful for single-molecule detection.

  12. Viral infection triggers rapid differentiation of human blood monocytes into dendritic cells.

    Science.gov (United States)

    Hou, Wanqiu; Gibbs, James S; Lu, Xiuju; Brooke, Christopher B; Roy, Devika; Modlin, Robert L; Bennink, Jack R; Yewdell, Jonathan W

    2012-03-29

    Surprisingly little is known about the interaction of human blood mononuclear cells with viruses. Here, we show that monocytes are the predominant cell type infected when peripheral blood mononuclear cells are exposed to viruses ex vivo. Remarkably, infection with vesicular stomatitis virus, vaccinia virus, and a variety of influenza A viruses (including circulating swine-origin virus) induces monocytes to differentiate within 18 hours into CD16(-)CD83(+) mature dendritic cells with enhanced capacity to activate T cells. Differentiation into dendritic cells does not require cell division and occurs despite the synthesis of viral proteins, which demonstrates that monocytes counteract the capacity of these highly lytic viruses to hijack host cell biosynthetic capacity. Indeed, differentiation requires infectious virus and viral protein synthesis. These findings demonstrate that monocytes are uniquely susceptible to viral infection among blood mononuclear cells, with the likely purpose of generating cells with enhanced capacity to activate innate and acquired antiviral immunity.

  13. Kaposi's-sarcoma-associated-herpesvirus-activated dendritic cells promote HIV-1 trans-infection and suppress CD4{sup +} T cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wan; Qin, Yan; Bai, Lei [Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, the Chinese Academy of Sciences, Shanghai (China); Graduate School of the Chinese Academy of Sciences, Beijing (China); Lan, Ke [Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, the Chinese Academy of Sciences, Shanghai (China); Wang, Jian-Hua, E-mail: Jh_wang@sibs.ac.cn [Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, the Chinese Academy of Sciences, Shanghai (China)

    2013-06-05

    Infection of Kaposi's sarcoma-associated herpesvirus (KSHV) is commonly occurred in AIDS patients. KSHV and HIV-1 act cooperatively in regulating infection with each other and in human carcinogenesis. Dendritic cells (DCs), as the pivotal cells in host immunity, may be modulated by both viruses, for immunoevasion and dissemination, therefore, the interaction between DCs and each virus has been a prior focus for pathogenesis elucidation. Here, we assessed the potential effect of KSHV on DC–HIV-1 interaction. We found that KSHV stimulation could promote maturation of monocyte-derived DCs (MDDCs) and impaired the ability of MDDCs to drive proliferation of resting CD4{sup +} T cells, demonstrating the immunosuppression induced by KSHV. More importantly, KSHV-stimulated MDDCs could capture more HIV-1 and efficiently transferred these infectious viruses to Hut/CCR5 T cell line. Our results reveal the novel modulation of DC-mediated HIV-1 dissemination by KSHV, and highlight the importance of studying DC–HIV-1 interaction to elucidate HIV/AIDS pathogenesis. - Highlights: ► KSHV impaired the ability of MDDCs to drive proliferation of resting CD4{sup +} T cells. ► KSHV stimulation matured MDDCs and enhanced HIV-1 endocytosis. ► KSHV stimulated MDDCs increased ICAM-1 expression and tighten contact with T cells. ► KSHV-stimulated MDDCs promoted HIV-1 trans-infection of CD4{sup +} T cells.

  14. Is Enhanced Physical Activity Possible Using Active Videogames?

    OpenAIRE

    Baranowski, Tom; Baranowski, Janice; O'Connor, Teresia; Lu, Amy Shirong; Thompson, Debbe

    2012-01-01

    Our research indicated that 10–12-year-old children receiving two active Wii™ (Nintendo®; Nintendo of America, Inc., Redmond, WA) console videogames were no more physically active than children receiving two inactive videogames. Research is needed on how active videogames may increase physical activity.

  15. Is Enhanced Physical Activity Possible Using Active Videogames?

    Science.gov (United States)

    Baranowski, Tom; Baranowski, Janice; O'Connor, Teresia; Lu, Amy Shirong; Thompson, Debbe

    2012-06-01

    Our research indicated that 10-12-year-old children receiving two active Wii(™) (Nintendo(®); Nintendo of America, Inc., Redmond, WA) console videogames were no more physically active than children receiving two inactive videogames. Research is needed on how active videogames may increase physical activity.

  16. Enhanced casein kinase II activity in human tumour cell cultures

    DEFF Research Database (Denmark)

    Prowald, K; Fischer, H; Issinger, O G

    1984-01-01

    Casein kinase II (CKII) activity is enhanced as much as 2-3 fold in established and 4-5-fold in transformed human cell lines when compared to that of fibroblasts and primary human tumour cell cultures where CKII activity never exceeded a basic level. The high activity of CKII in transformed cells...

  17. RIG-I Helicase-Independent Pathway in Sendai Virus-Activated Dendritic Cells Is Critical for Preventing Lung Metastasis of AT6.3 Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Tomonori Kato

    2010-11-01

    Full Text Available We recently demonstrated highly efficient antitumor immunity against dermal tumors of B16F10 murine melanoma with the use of dendritic cells (DCs activated by replication-competent, as well as nontransmissible-type, recombinant Sendai viruses (rSeV, and proposed a new concept, “immunostimulatory virotherapy,” for cancer immunotherapy. However, there has been little information on the efficacies of thismethod: 1 inmore clinically relevant situations including metastatic diseases, 2 on other tumor types and other animal species, and 3 on the related molecular/cellular mechanisms. In this study, therefore, we investigated the efficacy of vaccinating DCs activated by fusion gene-deleted nontransmissible rSeV on a rat model of lung metastasis using a highly malignant subline of Dunning R-3327 prostate cancer, AT6.3. rSeV/dF-green fluorescent protein (GFP-activated bone marrow-derived DCs (rSeV/dF-GFP-DC, consistent with results previously observed in murine DCs. Vaccination of rSeV/dF-GFP-DC was highly effective at preventing lung metastasis after intravenous loading of R-3327 tumor cells, compared with the effects observed with immature DCs or lipopolysaccharide-activated DCs. Interestingly, neither CTL activity nor DC trafficking showed any apparent difference among groups. Notably, rSeV/dF-DCs expressing a dominant-negative mutant of retinoic acid-inducible gene I (RIG-I (rSeV/dF-RIGIC-DC, an RNA helicase that recognizes the rSeV genome for inducing type I interferons, largely lost the expression of proinflammatory cytokines without any impairment of antitumor activity. These results indicate the essential role of RIG-I-independent signaling on antimetastatic effect induced by rSeV-activated DCs and may provide important insights to DC-based immunotherapy for advanced malignancies.

  18. Dysfunction of cortical dendritic integration in neuropathic pain reversed by serotoninergic neuromodulation.

    Science.gov (United States)

    Santello, Mirko; Nevian, Thomas

    2015-04-08

    Neuropathic pain is caused by long-term modifications of neuronal function in the peripheral nervous system, the spinal cord, and supraspinal areas. Although functional changes in the forebrain are thought to contribute to the development of persistent pain, their significance and precise subcellular nature remain unexplored. Using somatic and dendritic whole-cell patch-clamp recordings from neurons in the anterior cingulate cortex, we discovered that sciatic nerve injury caused an activity-dependent dysfunction of hyperpolarization-activated cyclic nucleotide-regulated (HCN) channels in the dendrites of layer 5 pyramidal neurons resulting in enhanced integration of excitatory postsynaptic inputs and increased neuronal firing. Specific activation of the serotonin receptor type 7 (5-HT7R) alleviated the lesion-induced pathology by increasing HCN channel function, restoring normal dendritic integration, and reducing mechanical pain hypersensitivity in nerve-injured animals in vivo. Thus, serotoninergic neuromodulation at the forebrain level can reverse the dendritic dysfunction induced by neuropathic pain and may represent a potential therapeutical target.

  19. Transient receptor potential ankyrin 1 activation enhances hapten sensitization in a T-helper type 2-driven fluorescein isothiocyanate-induced contact hypersensitivity mouse model

    Energy Technology Data Exchange (ETDEWEB)

    Shiba, Takahiro; Tamai, Takuma; Sahara, Yurina; Kurohane, Kohta [Laboratory of Microbiology and Immunology, School of Pharmaceutical Sciences, University of Shizuoka, 52‐1 Yada, Suruga-ku, Shizuoka City, Shizuoka 422‐8526 (Japan); Watanabe, Tatsuo [Laboratory of Food Chemistry, School of Food and Nutritional Sciences, University of Shizuoka, 52‐1 Yada, Suruga-ku, Shizuoka City, Shizuoka 422‐8526 (Japan); Imai, Yasuyuki, E-mail: imai@u-shizuoka-ken.ac.jp [Laboratory of Microbiology and Immunology, School of Pharmaceutical Sciences, University of Shizuoka, 52‐1 Yada, Suruga-ku, Shizuoka City, Shizuoka 422‐8526 (Japan)

    2012-11-01

    Some chemicals contribute to the development of allergies by increasing the immunogenicity of other allergens. We have demonstrated that several phthalate esters, including dibutyl phthalate (DBP), enhance skin sensitization to fluorescein isothiocyanate (FITC) in a mouse contact hypersensitivity model, in which the T-helper type 2 (Th2) response is essential. On the other hand, some phthalate esters were found to activate transient receptor potential ankyrin 1 (TRPA1) cation channels on sensory neurons. We then found a positive correlation between the enhancing effects of several types of phthalate esters on skin sensitization to FITC and their ability to activate TRPA1. Here we examined the involvement of TRPA1 in sensitization to FITC by using TRPA1 agonists other than phthalate esters. During skin sensitization to FITC, the TRPA1 agonists (menthol, carvacrol, cinnamaldehyde and DBP) augmented the ear-swelling response as well as trafficking of FITC-presenting dendritic cells to draining lymph nodes. We confirmed that these TRPA1 agonists induced calcium influx into TRPA1-expressing Chinese hamster ovary (CHO) cells. We also found that TRPA1 antagonist HC-030031 inhibited DBP-induced calcium influx into TRPA1-expressing CHO cells. After pretreatment with this antagonist upon skin sensitization to FITC, the enhancing effect of DBP on sensitization was suppressed. These results suggest that TRPA1 activation will become a useful marker to find chemicals that facilitate sensitization in combination with other immunogenic haptens. -- Highlights: ► Role of TRPA1 activation was revealed in a mouse model of skin sensitization to FITC. ► TRPA1 agonists enhanced skin sensitization as well as dendritic cell trafficking. ► Dibutyl phthalate (DBP) has been shown to enhance skin sensitization to FITC. ► TRPA1 activation by DBP was inhibited by a selective antagonist, HC-030031. ► HC-030031 inhibited the enhancing effect of DBP on skin sensitization to FITC.

  20. Lenalidomide enhances antigen-specific activity and decreases CD45RA expression of T cells from patients with multiple myeloma.

    Science.gov (United States)

    Neuber, Brigitte; Herth, Isabelle; Tolliver, Claudia; Schoenland, Stefan; Hegenbart, Ute; Hose, Dirk; Witzens-Harig, Mathias; Ho, Anthony D; Goldschmidt, Hartmut; Klein, Bernard; Hundemer, Michael

    2011-07-15

    The aim of this study was to investigate whether the specific T cell response against the multiple myeloma Ag HM1.24 is enhanced by the immunomodulatory drug lenalidomide (Revlimid). Ag-specific CD3(+)CD8(+) T cells against the HM1.24 Ag were expanded in vitro by dendritic cells in 29 healthy donors and 26 patients with plasma cell dyscrasias. Ag-specific activation was analyzed by IFN-γ, granzyme B, and perforin secretion using ELISA, ELISPOT assay, and intracellular staining, and generation of Ag-specific T cells was analyzed by tetramer staining. Expression of T cell maturation markers (CD45RA, CD45R0, CCR7, and CD28) was investigated by flow cytometry. We found that activation of HM1.24-specific T cells from healthy donors and patients with plasma cell dyscrasias was enhanced significantly by lenalidomide and furthermore that the impact of lenalidomide on T cells depends on the duration of the exposure. Notably, lenalidomide supports the downregulation of CD45RA on T cells upon activation, observed in healthy donors and in patients in vitro and also in patients during lenalidomide therapy in vivo. We showed for the first time, to our knowledge, that lenalidomide enhances the Ag-specific activation of T cells and the subsequent downregulation of CD45RA expression of T cells in vitro and in vivo.

  1. Gold-coated silver dendrites as SERS substrates with an improved lifetime.

    Science.gov (United States)

    Gutés, Albert; Maboudian, Roya; Carraro, Carlo

    2012-12-21

    Nanostructured silver is known to yield the highest signal-enhancement factors in surface-enhanced Raman spectroscopy, but its low chemical stability toward oxidation presents a challenge in the realization of Ag-based SERS substrates with long operating lifetimes. Here, a study of the long-term stability of silver dendrites as SERS substrates is reported. SERS spectra of 1,2-benzenedithiol monolayers on Ag dendrites, acquired over a period of time in excess of 1 year, shows appreciable degradation with time. However, no degradation is observed in the spectra of monolayers deposited on Ag dendrites that were coated with a monolayer-thin Au film deposited by an immersion plating process. X-ray photoelectron spectra confirm the oxidation of the uncoated Ag dendrites whereas no chemical changes are detected in the Au-coated ones. These results suggest that the galvanic displacement of Au on preformed Ag nanostructures provides a suitable route to producing SERS-active substrates with long operating and/or shelf lifetimes.

  2. Polypeptides having cellulolytic enhancing activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu; Tang, Lan; Henriksen, Svend Hostgaard Bang

    2016-05-17

    The present invention provides isolated polypeptides having cellulolytic enhancing activity and isolated polynucleotides encoding the polypeptides. The invention also provides nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  3. Chronic alcohol consumption enhances iNKT cell maturation and activation.

    Science.gov (United States)

    Zhang, Hui; Zhang, Faya; Zhu, Zhaohui; Luong, Dung; Meadows, Gary G

    2015-01-15

    Alcohol consumption exhibits diverse effects on different types of immune cells. NKT cells are a unique T cell population and play important immunoregulatory roles in different types of immune responses. The effects of chronic alcohol consumption on NKT cells remain to be elucidated. Using a mouse model of chronic alcohol consumption, we found that alcohol increases the percentage of NKT cells, especially iNKT cells in the thymus and liver, but not in the spleen or blood. Alcohol consumption decreases the percentage of NK1.1(-) iNKT cells in the total iNKT cell population in all of the tissues and organs examined. In the thymus, alcohol consumption increases the number of NK1.1(+)CD44(hi) mature iNKT cells but does not alter the number of NK1.1(-) immature iNKT cells. A BrdU incorporation assay shows that alcohol consumption increases the proliferation of thymic NK1.1(-) iNKT cells, especially the NK1.1(-)CD44(lo) Stage I iNKT cells. The percentage of NKG2A(+) iNKT cells increases in all of the tissues and organs examined; whereas CXCR3(+) iNKT cells only increases in the thymus of alcohol-consuming mice. Chronic alcohol consumption increases the percentage of IFN-γ-producing iNKT cells and increases the blood concentration of IFN-γ and IL-12 after in vivo α-galactosylceramide (αGalCer) stimulation. Consistent with the increased cytokine production, the in vivo activation of iNKT cells also enhances the activation of dendritic cells (DC) and NK, B, and T cells in the alcohol-consuming mice. Taken together the data indicate that chronic alcohol consumption enhances iNKT cell maturation and activation, which favors the Th1 immune response.

  4. Active tails enhance arboreal acrobatics in geckos

    OpenAIRE

    Jusufi, Ardian; Goldman, Daniel I.; Revzen, Shai; Full, Robert J.

    2008-01-01

    Geckos are nature's elite climbers. Their remarkable climbing feats have been attributed to specialized feet with hairy toes that uncurl and peel in milliseconds. Here, we report that the secret to the gecko's arboreal acrobatics includes an active tail. We examine the tail's role during rapid climbing, aerial descent, and gliding. We show that a gecko's tail functions as an emergency fifth leg to prevent falling during rapid climbing. A response initiated by slipping causes the tail tip to p...

  5. Differential partial activation phenotype and production of tumour necrosis factor-α by conventional dendritic cells in response to lipopolysaccharide in HIV+ viraemic subjects and HIV+ controllers.

    Science.gov (United States)

    Camacho-Sandoval, R; Del Río Estrada, P M; Rivero-Arrieta, A; Reyes-Terán, G; Bonifaz, L C

    2014-12-01

    HIV(+) subjects are reported to have increased soluble CD14 (sCD14) in plasma, an indicator of microbial translocation. We evaluated if microbial translocation has a differential impact on the activation and function of conventional dendritic cells (cDC) from viraemic HIV(+) subjects and HIV(+) controllers (CTs). The HIV(+) subjects were classified into two groups according to their plasma viral load (pVL): CT and viraemic. Subjects without HIV were included as controls (HIV(-) ). The frequencies and phenotypes of cDC from these subjects were evaluated by multi-parameter flow cytometry. In addition, peripheral blood mononuclear cells (PBMCs) were stimulated with lipopolysaccharide (LPS) or single-stranded RNA40 (ssRNA40), the phenotype of the cDC and the intracellular production of tumour necrosis factor (TNF)-α by the cDC were evaluated by flow cytometry. We observed a partial activation phenotype for the cDC in the viraemic subjects and CTs ex vivo and after LPS activation, which showed differences in the expression of CD40 and CD86. Furthermore, in response to LPS the cDC from the viraemic subjects produced more TNF-α compared to the cDC from CTs. Interestingly, the percentage of TNF-α(+) cDC was found to be correlated positively with the pVL. The partial activation of cDC and the over-production of TNF-α in response to LPS in viraemic HIV(+) subjects might be related to the increased chronic activation observed in these subjects. In contrast, cDC from CTs seem to have a regulated response to LPS, indicating that they respond differently to chronic immune activation. These results may have implications in the development of HIV therapies and vaccines using DC.

  6. Differential partial activation phenotype and production of tumour necrosis factor-α by conventional dendritic cells in response to lipopolysaccharide in HIV+ viraemic subjects and HIV+ controllers

    Science.gov (United States)

    Camacho-Sandoval, R; Del Río Estrada, P M; Rivero-Arrieta, A; Reyes-Terán, G; Bonifaz, L C

    2014-01-01

    HIV+ subjects are reported to have increased soluble CD14 (sCD14) in plasma, an indicator of microbial translocation. We evaluated if microbial translocation has a differential impact on the activation and function of conventional dendritic cells (cDC) from viraemic HIV+ subjects and HIV+ controllers (CTs). The HIV+ subjects were classified into two groups according to their plasma viral load (pVL): CT and viraemic. Subjects without HIV were included as controls (HIV–). The frequencies and phenotypes of cDC from these subjects were evaluated by multi-parameter flow cytometry. In addition, peripheral blood mononuclear cells (PBMCs) were stimulated with lipopolysaccharide (LPS) or single-stranded RNA40 (ssRNA40), the phenotype of the cDC and the intracellular production of tumour necrosis factor (TNF)-α by the cDC were evaluated by flow cytometry. We observed a partial activation phenotype for the cDC in the viraemic subjects and CTs ex vivo and after LPS activation, which showed differences in the expression of CD40 and CD86. Furthermore, in response to LPS the cDC from the viraemic subjects produced more TNF-α compared to the cDC from CTs. Interestingly, the percentage of TNF-α+ cDC was found to be correlated positively with the pVL. The partial activation of cDC and the over-production of TNF-α in response to LPS in viraemic HIV+ subjects might be related to the increased chronic activation observed in these subjects. In contrast, cDC from CTs seem to have a regulated response to LPS, indicating that they respond differently to chronic immune activation. These results may have implications in the development of HIV therapies and vaccines using DC. PMID:25130456

  7. Lactobacillus gasseri SBT2055 induces TGF-β expression in dendritic cells and activates TLR2 signal to produce IgA in the small intestine.

    Science.gov (United States)

    Sakai, Fumihiko; Hosoya, Tomohiro; Ono-Ohmachi, Aiko; Ukibe, Ken; Ogawa, Akihiro; Moriya, Tomohiro; Kadooka, Yukio; Shiozaki, Takuya; Nakagawa, Hisako; Nakayama, Yosuke; Miyazaki, Tadaaki

    2014-01-01

    Probiotic bacteria provide benefits in enhancing host immune responses and protecting against infection. Induction of IgA production by oral administration of probiotic bacteria in the intestine has been considered to be one reason for this beneficial effect, but the mechanisms of the effect are poorly understood. Lactobacillus gasseri SBT2055 (LG2055) is a probiotic bacterium with properties such as bile tolerance, ability to improve the intestinal environment, and it has preventive effects related to abdominal adiposity. In this study, we have found that oral administration of LG2055 induced IgA production and increased the rate of IgA(+) cell population in Peyer's patch and in the lamina propria of the mouse small intestine. The LG2055 markedly increased the amount of IgA in a co-culture of B cells and bone marrow derived dendritic cells (BMDC), and TLR2 signal is critical for it. In addition, it is demonstrated that LG2055 stimulates BMDC to promote the production of TGF-β, BAFF, IL-6, and IL-10, all critical for IgA production from B cells. Combined stimulation of B cells with BAFF and LG2055 enhanced the induction of IgA production. Further, TGF-β signal was shown to be critical for LG2055-induced IgA production in the B cell and BMDC co-culture system, but TGF-β did not induce IgA production in a culture of only B cells stimulated with LG2055. Furthermore, TGF-β was critical for the production of BAFF, IL-6, IL-10, and TGF-β itself from LG2055-stimulated BMDC. These results demonstrate that TGF-β was produced by BMDC stimulated with LG2055 and it has an autocrine/paracrine function essential for BMDC to induce the production of BAFF, IL-6, and IL-10.

  8. Lactobacillus gasseri SBT2055 induces TGF-β expression in dendritic cells and activates TLR2 signal to produce IgA in the small intestine.

    Directory of Open Access Journals (Sweden)

    Fumihiko Sakai

    Full Text Available Probiotic bacteria provide benefits in enhancing host immune responses and protecting against infection. Induction of IgA production by oral administration of probiotic bacteria in the intestine has been considered to be one reason for this beneficial effect, but the mechanisms of the effect are poorly understood. Lactobacillus gasseri SBT2055 (LG2055 is a probiotic bacterium with properties such as bile tolerance, ability to improve the intestinal environment, and it has preventive effects related to abdominal adiposity. In this study, we have found that oral administration of LG2055 induced IgA production and increased the rate of IgA(+ cell population in Peyer's patch and in the lamina propria of the mouse small intestine. The LG2055 markedly increased the amount of IgA in a co-culture of B cells and bone marrow derived dendritic cells (BMDC, and TLR2 signal is critical for it. In addition, it is demonstrated that LG2055 stimulates BMDC to promote the production of TGF-β, BAFF, IL-6, and IL-10, all critical for IgA production from B cells. Combined stimulation of B cells with BAFF and LG2055 enhanced the induction of IgA production. Further, TGF-β signal was shown to be critical for LG2055-induced IgA production in the B cell and BMDC co-culture system, but TGF-β did not induce IgA production in a culture of only B cells stimulated with LG2055. Furthermore, TGF-β was critical for the production of BAFF, IL-6, IL-10, and TGF-β itself from LG2055-stimulated BMDC. These results demonstrate that TGF-β was produced by BMDC stimulated with LG2055 and it has an autocrine/paracrine function essential for BMDC to induce the production of BAFF, IL-6, and IL-10.

  9. Impact of p38 mitogen-activated protein kinase inhibition on immunostimulatory properties of human 6-sulfo LacNAc dendritic cells.

    Science.gov (United States)

    Langosch, Saskia; Wehner, Rebekka; Malecka, Ania; Franks, Hester A; Schäkel, Knut; Bachmann, Michael; Jackson, Andrew M; Schmitz, Marc

    2016-02-01

    p38 Mitogen-activated protein kinase (MAPK) plays a crucial role in the induction and regulation of innate and adaptive immunity. Furthermore, p38 MAPK can promote tumor invasion, metastasis, and angiogenesis. Based on these properties, p38 MAPK inhibitors emerged as interesting candidates for the treatment of immune-mediated disorders and cancer. However, the majority of p38 MAPK inhibitor-based clinical trials failed due to poor efficacy or toxicity. Further studies investigating the influence of p38 MAPK inhibitors on immunomodulatory capabilities of human immune cells may improve their therapeutic potential. Here, we explored the impact of the p38 MAPK inhibitor SB203580 on the pro-inflammatory properties of native human 6-sulfo LacNAc dendritic cells (slanDCs). SB203580 did not modulate maturation of slanDCs and their capacity to promote T-cell proliferation. However, SB203580 significantly reduced the production of pro-inflammatory cytokines by activated slanDCs. Moreover, inhibition of p38 MAPK impaired the ability of slanDCs to differentiate naïve CD4(+) T cells into T helper 1 cells and to stimulate interferon-γ secretion by natural killer cells. These results provide evidence that SB203580 significantly inhibits various important immunostimulatory properties of slanDCs. This may have implications for the design of p38 MAPK inhibitor-based treatment strategies for immune-mediated disorders and cancer.

  10. Immunomodulatory activity of the water extract of Thymus vulgaris, Thymus daenensis, and Zataria multiflora on dendritic cells and T cells responses.

    Science.gov (United States)

    Amirghofran, Zahra; Ahmadi, Hossein; Karimi, Mohammad Hossein

    2012-01-01

    Thymus vulgaris (thyme), Thymus daenensis, and Zataria multiflora are medicinal plants being used widely for infections and inflammatory diseases in folk medicine. In this study, the effects of the water extract of these plants on the activation of dendritic cells (DCs) and T cells was investigated. Both T. vulgaris and Z. multiflora decreased the proliferation of mitogen-stimulated lymphocytes, whereas T. daenensis induced cell proliferation in a dose-dependent manner (p < 0.001). All the three plants increased the CD40 expression on DCs (p < 0.04). The extent of allogenic T cell proliferation in the presence of T. vulgaris and Z. multiflora extracts was significantly decreased (p < 0.02). The effect of the extracts on secretion of IFN-γ and IL-4 cytokines showed that none of the extracts influenced the pattern of cytokine production by T helper (Th) cells toward a Thl or Th2 profile. In conclusion, all the extracts had the ability to activate DCs. Whereas Z. multiflora and T. vulgaris extracts showed immunoihibitory effects on allogenic T cell proliferation, the main effect of T. daenensis was on mitogenic T cell response. These data may partly explain the mechanisms underlying the beneficial immunomodulatory effects of these extracts in infections and immune-related diseases.

  11. Mycobacterium tuberculosis PE25/PPE41 protein complex induces activation and maturation of dendritic cells and drives Th2-biased immune responses.

    Science.gov (United States)

    Chen, Wei; Bao, Yige; Chen, Xuerong; Burton, Jeremy; Gong, Xueli; Gu, Dongqing; Mi, Youjun; Bao, Lang

    2016-04-01

    Mycobacterium tuberculosis evades innate host immune responses by parasitizing macrophages and causes significant morbidity and mortality around the world. A mycobacterial antigen that can activate dendritic cells (DCs) and elicit effective host innate immune responses will be vital to the development of an effective TB vaccine. The M. tuberculosis genes PE25/PPE41 encode proteins which have been associated with evasion of the host immune response. We constructed a PE25/PPE41 complex gene via splicing by overlapping extension and expressed it successfully in E. coli. We investigated whether this protein complex could interact with DCs to induce effective host immune responses. The PE25/PPE41 protein complex induced maturation of isolated mouse DCs in vitro, increasing expression of cell surface markers (CD80, CD86 and MHC-II), thereby promoting Th2 polarization via secretion of pro-inflammatory cytokines IL-4 and IL-10. In addition, PE25/PPE41 protein complex-activated DCs induced proliferation of mouse CD4(+) and CD8(+) T cells, and a strong humoral response in immunized mice. The sera of five TB patients were also highly reactive to this antigen. These findings suggest that interaction of the PE25/PPE41 protein complex with DCs may be of great immunological significance.

  12. Dendritic cell CNS recruitment correlates with disease severity in EAE via CCL2 chemotaxis at the blood–brain barrier through paracellular transmigration and ERK activation

    Directory of Open Access Journals (Sweden)

    Sagar Divya

    2012-10-01

    Full Text Available Abstract Background Transmigration of circulating dendritic cells (DCs into the central nervous system (CNS across the blood–brain barrier (BBB has not thus far been investigated. An increase in immune cell infiltration across the BBB, uncontrolled activation and antigen presentation are influenced by chemokines. Chemokine ligand 2 (CCL2 is a potent chemoattractant known to be secreted by the BBB but has not been implicated in the recruitment of DCs specifically at the BBB. Methods Experimental autoimmune encephalomyelitis (EAE was induced in C57BL/6 mice by injection of MOG35–55 peptide and pertussis toxin intraperitoneally. Animals with increasing degree of EAE score were sacrificed and subjected to near-infrared and fluorescence imaging analysis to detect and localize the accumulation of CD11c+-labeled DCs with respect to CCL2 expression. To further characterize the direct effect of CCL2 in DC trafficking at the BBB, we utilized an in vitro BBB model consisting of human brain microvascular endothelial cells to compare migratory patterns of monocyte-derived dendritic cells, CD4+ and CD8+ T cells. Further, this model was used to image transmigration using fluorescence microcopy and to assess specific molecular signaling pathways involved in transmigration. Results Near-infrared imaging of DC transmigration correlated with the severity of inflammation during EAE. Ex vivo histology confirmed the presence of CCL2 in EAE lesions, with DCs emerging from perivascular spaces. DCs exhibited more efficient transmigration than T cells in BBB model studies. These observations correlated with transwell imaging, which indicated a paracellular versus transcellular pattern of migration by DCs and T cells. Moreover, at the molecular level, CCL2 seems to facilitate DC transmigration in an ERK1/2-dependent manner. Conclusion CNS recruitment of DCs correlates with disease severity in EAE via CCL2 chemotaxis and paracellular transmigration across the BBB

  13. Enhanced sensing of molecular optical activity with plasmonic nanohole arrays

    CERN Document Server

    Gorkunov, Maxim V; Kondratov, Alexey V

    2016-01-01

    Prospects of using metal hole arrays for the enhanced optical detection of molecular chirality in nanosize volumes are investigated. Light transmission through the holes filled with an optically active material is modeled and the activity enhancement by more than an order of magnitude is demonstrated. The spatial resolution of the chirality detection is shown to be of a few tens of nanometers. From comparing the effect in arrays of cylindrical holes and holes of complex chiral shape, it is concluded that the detection sensitivity is determined by the plasmonic near field enhancement. The intrinsic chirality of the arrays due to their shape appears to be less important.

  14. Endogenously produced TNF-α contributes to the expression of CXCL10/IP-10 in IFN-λ3-activated plasmacytoid dendritic cells.

    Science.gov (United States)

    Finotti, Giulia; Tamassia, Nicola; Calzetti, Federica; Fattovich, Giovanna; Cassatella, Marco A

    2016-01-01

    The interplay between IFN-λs and dendritic cells is becoming increasingly relevant, particularly in light of their key role in inducing the antiviral state, including in hepatitis C virus infection. In this work, we have analyzed extensively how human plasmacytoid dendritic cells respond to IFN-λ3. We report that plasmacytoid dendritic cells incubated with IFN-λ3 prolong their survival; alter their expression pattern of surface HLA-DRα, CD123, CD86, and CD303; and time dependently produce IFN-α, CXCL10/IFN-γ-induced protein 10, and even modest quantities of TNF-α. Nevertheless, endogenously produced TNF-α, but not IFN-α, was found to be essential for driving the expression of CXCL10/IFN-γ-induced protein 10 in IFN-λ3-treated plasmacytoid dendritic cells, as revealed by neutralizing experiments by use of adalimumab, etanercept, and infliximab. We also observed that based on the kinetics and levels of IFN-α and CXCL10/IFN-γ-induced protein 10 produced by their IFN-λ3-treated plasmacytoid dendritic cells, healthy donors could be categorized into 2 and 3 groups, respectively. In particular, we identified a group of donors whose plasmacytoid dendritic cells produced modest quantities of CXCL10/IFN-γ-induced protein 10; another one whose plasmacytoid dendritic cells produced elevated CXCL10/IFN-γ-induced protein 10 levels, already after 18 h, declining thereafter; and a 3rd group characterized by plasmacytoid dendritic cells releasing very high CXCL10/IFN-γ-induced protein 10 levels after 42 h only. Finally, we report that in plasmacytoid dendritic cells, equivalent concentrations of IFN-λ3 and IFN-λ1 promote survival, antigen modulation, and cytokine production in a comparable manner and without acting additively/synergistically. Altogether, data not only extend the knowledge on the biologic effects that IFN-λs exert on plasmacytoid dendritic cells but also add novel light to the networking between IFN-λs and plasmacytoid dendritic cells in fighting

  15. Accelerated dendritic development of rat cortical pyramidal cells and interneurons after biolistic transfection with BDNF and NT4/5.

    Science.gov (United States)

    Wirth, Marcus J; Brun, Annika; Grabert, Jochen; Patz, Silke; Wahle, Petra

    2003-12-01

    Neurotrophins are candidate molecules for regulating dendritogenesis. We report here on dendritic growth of rat visual cortex pyramidal and interneurons overexpressing 'brain-derived neurotrophic factor' BDNF and 'neurotrophin 4/5' NT4/5. Neurons in organotypic cultures were transfected with plasmids encoding either 'enhanced green fluorescent protein' EGFP, BDNF/EGFP or NT4/5/EGFP either at the day of birth with analysis at 5 days in vitro, or at 5 days in vitro with analysis at 10 days in vitro. In pyramidal neurons, both TrkB ligands increased dendritic length and number of segments without affecting maximum branch order and number of primary dendrites. In the early time window, only infragranular neurons were responsive. Neurons in layers II/III became responsive to NT4/5, but not BDNF, during the later time window. BDNF and NT4/5 transfectants at 10 days in vitro had still significantly shorter dendrites than adult pyramidal neurons, suggesting a massive growth spurt after 10 days in vitro. However, segment numbers were already in the range of adult neurons. Although this suggested a role for BDNF, long-term activity-deprived, and thus BDNF-deprived, pyramidal cells developed a dendritic complexity not different from neurons in active cultures except for higher spine densities on neurons of layers II/III and VI. Neutralization of endogenous NT4/5 causes shorter and less branched dendrites at 10 days in vitro suggesting an essential role for NT4/5. Neutralization of BDNF had no effect. Transfected multipolar interneurons became identifiable during the second time window. Both TrkB ligands significantly increased number of segments and branch order towards the adult state with little effects on dendritic length. The results suggested that early in development BDNF and NT4/5 probably accelerate dendritogenesis in an autocrine fashion. In particular, branch formation was advanced towards the adult pattern in pyramidal cells and interneurons.

  16. Optimization principles of dendritic structure

    Directory of Open Access Journals (Sweden)

    Borst Alexander

    2007-06-01

    Full Text Available Abstract Background Dendrites are the most conspicuous feature of neurons. However, the principles determining their structure are poorly understood. By employing cable theory and, for the first time, graph theory, we describe dendritic anatomy solely on the basis of optimizing synaptic efficacy with minimal resources. Results We show that dendritic branching topology can be well described by minimizing the path length from the neuron's dendritic root to each of its synaptic inputs while constraining the total length of wiring. Tapering of diameter toward the dendrite tip – a feature of many neurons – optimizes charge transfer from all dendritic synapses to the dendritic root while housekeeping the amount of dendrite volume. As an example, we show how dendrites of fly neurons can be closely reconstructed based on these two principles alone.

  17. PEGylated dendritic diaminocyclohexyl-platinum (II) conjugates as pH-responsive drug delivery vehicles with enhanced tumor accumulation and antitumor efficacy.

    Science.gov (United States)

    Pan, Dayi; She, Wenchuan; Guo, Chunhua; Luo, Kui; Yi, Qiangying; Gu, Zhongwei

    2014-12-01

    Environmentally responsive peptide dendrimers loaded with drugs are suitable candidates for cancer therapy. In this study, we report the preparation and characterization of mPEGylated peptide dendrimer-linked diaminocyclohexyl platinum (II) (dendrimer-DACHPt) conjugates as pH-responsive drug delivery vehicles for tumor suppression in mice. The DACHPt has a molecular structure, is and activity closely related to oxaliplatin and was linked to dendrimer via N,O-chelate coordination. The products were pH-responsive and released drug significantly faster in acidic environments (pH 5.0) than pH 7.4. Consequently, the conjugates suppressed tumor growth better than clinical oxaliplatin(®) without inducing toxicity in an SKOV-3 human ovarian cancer xenograft. Through the systemic delivery of conjugates, 25-fold higher tumor platinum uptake at 36 h post-injection was seen observed due to the enhanced permeability and retention (EPR) effect thereby remarkably enhancing the therapeutic indexes of this small-molecule drug. Thus, the mPEGylated peptide dendrimer-linked DACH-platinum conjugates are novel potential drug delivery systems with implications in future ovarian cancer therapy.

  18. Implication of TLR- but not of NOD2-signaling pathways in dendritic cell activation by group B Streptococcus serotypes III and V.

    Directory of Open Access Journals (Sweden)

    Paul Lemire

    Full Text Available Group B Streptococcus (GBS is an important agent of life-threatening invasive infection. It has been previously shown that encapsulated type III GBS is easily internalized by dendritic cells (DCs, and that this internalization had an impact on cytokine production. The receptors underlying these processes are poorly characterized. Knowledge on the mechanisms used by type V GBS to activate DCs is minimal. In this work, we investigated the role of Toll-like receptor (TLR/MyD88 signaling pathway, the particular involvement of TLR2, and that of the intracellular sensing receptor NOD2 in the activation of DCs by types III and V GBS. The role of capsular polysaccharide (CPS, one of the most important GBS virulence factors in bacterial-DC interactions was evaluated using non-encapsulated mutants. Despite differences in the role of CPS between types III and V GBS in bacterial internalization and intracellular survival, no major differences were observed in their capacity to modulate release of cytokines by DC. For both serotypes, CPS had a minor role in this response. Production of cytokines by DCs was shown to strongly rely on MyD88-dependent signaling pathways, suggesting that DCs recognize GBS and become activated mostly through TLR signaling. Yet, GBS-infected TLR2-/- DCs only showed a partial reduction in the production of IL-6 and CXCL1 compared to control DCs. Surprisingly, CXCL10 release by type III or type V GBS-infected DCs was MyD88-independent. No differences in DC activation were observed between NOD2-/- and control DCs. These results demonstrate the involvement of various receptors and the complexity of the cytokine production pathways activated by GBS upon DC infection.

  19. In-vitro activation of cytotoxic T lymphocytes by fusion of mouse hepatocellular carcinoma cells and lymphotactin gene-modified dendritic cells

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To investigate the in-vitro activation of cytotoxic T lymphocytes (CTLs) by fusion of mouse hepatocellular carcinoma (HCC) cells and lymphotactin gene-modified dendritic cells (DCs).METHODS: Lymphotactin gene modified DCs (DCLptn) were prepared by lymphotactin recombinant adenovirus transduction of mature DCs which differentiated from mouse bone marrow cells by stimulation with granulocyte/macrophage colony-stimulating factor (GM-CSF), interleukin-4 (IL-4) and tumor necrosis factor alpha (TNF-α). DCLptn and H22 fusion was prepared using 50% PEG. Lymphotactin gene and protein expression levels were measured by RT-PCR and ELISA, respectively. Lymphotactin chemotactic responses were examined by in-vitro chemotaxis assay. In-vitro activation of CTLs by DCLptn/H22 fusion was measured by detecting CD25 expression and cytokine production after autologous T cell stimulation. Cytotoxic function of activated T lymphocytes stimulated with DCLptn/H22 cells was determined by LDH cytotoxicity assay.RESULTS: Lymphotactin gene could be efficiently transduced to DCs by adenovirus vector and showed an effective biological activity. After fusion, the hybrid DCLptn/H22 cells acquired the phenotypes of both DCLptn and H22 cells. In T cell proliferation assay, flow cytometry showed a very high CD25 expression, and cytokine release assay showed a significantly higher concentration of IFN-γ and IL-2 in DCLptn/H22 group than in DCLptn, DCLptn+H22, DC/H22 or H22 groups. Cytotoxicity assay revealed that T cells derived from DCLptn/H22 group had much higher anti-tumor activity than those derived from DCLptn, H22, DCLptn + H22, DC/H22 groups.CONCLUSION: Lymphotactin gene-modified dendritoma induces T-cell proliferation and strong CTL reaction against allogenic HCC cells. Immunization-engineered fusion hybrid vaccine is an attractive strategy in prevention and treatment of HCC metastases.

  20. Rabies virus infection induces type I interferon production in an IPS-1 dependent manner while dendritic cell activation relies on IFNAR signaling.

    Directory of Open Access Journals (Sweden)

    Elizabeth J Faul

    Full Text Available As with many viruses, rabies virus (RABV infection induces type I interferon (IFN production within the infected host cells. However, RABV has evolved mechanisms by which to inhibit IFN production in order to sustain infection. Here we show that RABV infection of dendritic cells (DC induces potent type I IFN production and DC activation. Although DCs are infected by RABV, the viral replication is highly suppressed in DCs, rendering the infection non-productive. We exploited this finding in bone marrow derived DCs (BMDC in order to differentiate which pattern recognition receptor(s (PRR is responsible for inducing type I IFN following infection with RABV. Our results indicate that BMDC activation and type I IFN production following a RABV infection is independent of TLR signaling. However, IPS-1 is essential for both BMDC activation and IFN production. Interestingly, we see that the BMDC activation is primarily due to signaling through the IFNAR and only marginally induced by the initial infection. To further identify the receptor recognizing RABV infection, we next analyzed BMDC from Mda-5-/- and RIG-I-/- mice. In the absence of either receptor, there is a significant decrease in BMDC activation at 12h post infection. However, only RIG-I-/- cells exhibit a delay in type I IFN production. In order to determine the role that IPS-1 plays in vivo, we infected mice with pathogenic RABV. We see that IPS-1-/- mice are more susceptible to infection than IPS-1+/+ mice and have a significantly increased incident of limb paralysis.

  1. Ikaros can enhance immune activity though the interaction with Autotaxin in LDIR exposed immune cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Jin; Kim, Min Young; Kim, Ji Young; Kim, Hee Sun; KIm, Cha Soon; Nam, Seon Young; Yang, Kwang Hee; Jin, Young Woo [Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd, Seoul (Korea, Republic of)

    2009-04-15

    Ikaros, one of transcription factors, plays major roles in the differentiation and biology of leukocytes, including all classes of lymphocytes (NK, T, and B cells), monocytes/macrophages, and dendritic cells. Ikaros was also shown to regulate early neutrophils differentiation. Therefore, Ikaros appears to be a major determinant in the development and function of immune system. Autotaxin (ATX), which is also called nucleotide pyrophosphatase/phosphodiesterase 2 (NPP2), is an exo-enzyme originally identified as a tumor cell autocrine motility factor. ATX functions as a lysophospholipase D, converting lysophosphatidylcholine (LPC) into the lipid mediator lysophosphatidic acid (LPA). LPA bind together with specific G protein-coupled receptors, which elicit a wide range of cellular responses including the cell proliferation, migration and neurite remodeling. In the Recent report, ATX stimulate human endothelial cells (HUVECs) growth and cytokine production. In our previous study, we showed that low-dose ionizing radiation (LDIR) enhanced the cell proliferation cell coupled with Ikaros phosphorylation. In addition, we found that LDIR increased the expression level of cyclin E and cdk2 protein in IM-9 B lymphoblast cells. In this report, therefore, we try to find Ikaros binding proteins after LDIR in IM-9 lymphoblastic cell lines to examine whether the effects of LDIR induced cell proliferation are one of immune activation responses or not.

  2. Facile synthesis of Ag dendrites on Al foil via galvanic replacement reaction with [Ag(NH{sub 3}){sub 2}]Cl for ultrasensitive SERS detecting of biomolecules

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiajia; Ye, Weichun [Department of Chemistry, Lanzhou University, Lanzhou 73000 (China); Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, Lanzhou 73000 (China); Wang, Chunming, E-mail: wangcm@lzu.edu.cn [Department of Chemistry, Lanzhou University, Lanzhou 73000 (China); Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, Lanzhou 73000 (China)

    2013-08-15

    Symmetric silver dendrites have been synthesized on commercial aluminum foil via galvanic replacement reaction with [Ag(NH{sub 3}){sub 2}]Cl. This process is facile and environmentally friendly, without the use of any templates, surfactants or oxidants, and also avoiding the introduction of fluoride anions as a strong toxicity resulting in hypocalcemia. The products were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM) and X-ray diffraction (XRD). SEM characterizations and electrochemical measurements including an electrochemical direct current polarization method and OCP-t technique demonstrate that chloride has proven to be the key factor to the formation of well-defined dendritic shape. The as-prepared Ag dendrites are developed as a surface-enhanced Raman scattering (SERS)-active platform for detection of folic acid, DNA and RNA with well resolved bands and high Raman intensities. The detection concentration for the three biomolecules reaches the level of 10{sup −12} M, and thus the symmetric silver dendrites can potentially be employed as effective SERS sensors for label-free and ultrasensitive biomolecule detection. - Highlights: • Simple galvanic replacement is used to synthesize Ag dendrites on commercial Al foils. • This method avoids the introduction of fluoride anions. • The as-prepared dendrites exhibit high SERS activities for biomolecules. • The detection concentration for the biomolecules reaches the level of 10{sup −12} M.

  3. Chronic alcohol consumption enhances iNKT cell maturation and activation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hui, E-mail: hzhang@wsu.edu; Zhang, Faya; Zhu, Zhaohui; Luong, Dung; Meadows, Gary G.

    2015-01-15

    Alcohol consumption exhibits diverse effects on different types of immune cells. NKT cells are a unique T cell population and play important immunoregulatory roles in different types of immune responses. The effects of chronic alcohol consumption on NKT cells remain to be elucidated. Using a mouse model of chronic alcohol consumption, we found that alcohol increases the percentage of NKT cells, especially iNKT cells in the thymus and liver, but not in the spleen or blood. Alcohol consumption decreases the percentage of NK1.1{sup −} iNKT cells in the total iNKT cell population in all of the tissues and organs examined. In the thymus, alcohol consumption increases the number of NK1.1{sup +}CD44{sup hi} mature iNKT cells but does not alter the number of NK1.1{sup −} immature iNKT cells. A BrdU incorporation assay shows that alcohol consumption increases the proliferation of thymic NK1.1{sup −} iNKT cells, especially the NK1.1{sup −}CD44{sup lo} Stage I iNKT cells. The percentage of NKG2A{sup +} iNKT cells increases in all of the tissues and organs examined; whereas CXCR3{sup +} iNKT cells only increases in the thymus of alcohol-consuming mice. Chronic alcohol consumption increases the percentage of IFN-γ-producing iNKT cells and increases the blood concentration of IFN-γ and IL-12 after in vivo α-galactosylceramide (αGalCer) stimulation. Consistent with the increased cytokine production, the in vivo activation of iNKT cells also enhances the activation of dendritic cells (DC) and NK, B, and T cells in the alcohol-consuming mice. Taken together the data indicate that chronic alcohol consumption enhances iNKT cell maturation and activation, which favors the Th1 immune response. - Highlights: • Chronic alcohol consumption increases iNKT cells in the thymus and liver • Chronic alcohol consumption enhances thymic Stage I iNKT cell proliferation • Chronic alcohol consumption enhances iNKT cell maturation in thymus and periphery • Chronic alcohol

  4. Filaria/Wolbachia activation of dendritic cells and development of Th1-associated responses is dependent on Toll-like receptor 2 in a mouse model of ocular onchocerciasis (river blindness).

    Science.gov (United States)

    Daehnel, K; Gillette-Ferguson, I; Hise, A G; Diaconu, E; Harling, M J; Heinzel, F P; Pearlman, E

    2007-09-01

    Toll-like receptors (TLRs) regulate dendritic cell function and activate signals that mediate the nature of the adaptive immune response. The current study examined the role of TLRs in dendritic cell activation and in regulating T cell and antibody responses to antigens from the filarial parasites Onchocerca volvulus and Brugia malayi, which cause river blindness and lymphatic filariasis, respectively. Bone-marrow-derived CD11c(+) cells from C57BL/6 and TLR4(-/-) mice produced high levels of IL-6 and RANTES, and showed elevated surface CD40 expression, whereas CD11c(+) cells from myeloid differentiation factor 88(-/-) (MyD88(-/-)), TLR2(-/-) and TLR2/4(-/-) mice were not activated. Similarly, IFN-gamma production by splenocytes from immunized TLR2(-/-) mice was significantly impaired compared with splenocytes from C57BL/6 and TLR4(-/-) mice. In contrast, there was no difference among these strains in Th2-associated responses including IL-5 production by splenocytes from immunized animals, serum IgE and IgG(1), or eosinophil infiltration into the corneal stroma. Neutrophil recruitment to the cornea and CXC chemokine production was inhibited in immunized TLR2(-/-) mice compared with C57BL/6 and TLR4(-/-) mice. Taken together, these findings demonstrate an essential role for TLR2 in filaria-induced dendritic cell activation, IFN-gamma production and neutrophil migration to the cornea, but does not affect filaria-induced Th2-associated responses.

  5. Active acromegaly enhances spontaneous parathyroid hormone pulsatility.

    Science.gov (United States)

    Mazziotti, Gherardo; Cimino, Vincenzo; De Menis, Ernesto; Bonadonna, Stefania; Bugari, Giovanna; De Marinis, Laura; Veldhuis, Johannes D; Giustina, Andrea

    2006-06-01

    In healthy subjects, parathyroid hormone (PTH) is secreted in a dual fashion, with low-amplitude and high-frequency pulses superimposed on tonic secretion. These 2 components of PTH secretion seem to have different effects on target organs. The aim of our study was to evaluate whether growth hormone excess in acromegaly may modify the spontaneous pulsatility of PTH. Five male patients with newly diagnosed active acromegaly and 8 healthy subjects were evaluated by 3-minute blood sampling for 6 hours. Plasma PTH concentrations were evaluated by multiparameter deconvolution analysis. Plasma PTH release profiles were also subjected to an approximate entropy (ApEn) estimate, which provides an ensemble measure of the serial regularity or orderliness of the release process. In acromegalic patients, baseline serum PTH values were not significantly different from those measured in the healthy subjects, as well as tonic PTH secretion rate, number of bursts, fractional pulsatile PTH secretion, and ApEn ratio. Conversely, PTH pulse half-duration was significantly longer in acromegalic patients vs healthy subjects (11.8+/-0.95 vs 6.9+/-1.6 minutes; P=.05), whereas PTH pulse mass showed a tendency (P=.06) to be significantly greater in acromegalic patients. These preliminary data suggest that growth hormone excess may affect PTH secretory dynamics in patients with acromegaly. Potentially negative bone effects of the modifications of PTH secretory pattern in acromegaly should be investigated.

  6. Immuno-modulatory activity of Ganoderma lucidum-derived polysacharide on human monocytoid dendritic cells pulsed with Der p 1 allergen

    Directory of Open Access Journals (Sweden)

    Lo Shih-Yen

    2011-05-01

    Full Text Available Abstract Background Ganoderma lucidum-derived polysaccharide (PS-G can rapidly and effectively promote the activation and maturation of immature dendritic cells (DCs, suggesting that PS-G possesses the capacity to regulate immune responses. This study aimed to clarify the immunologic effect of PS-G on monocyte-derived dendritic cells (MD-DCs from asthmatic children allergic to house dust mites. The MD-DCs were stimulated for 24 h with the related allergen, Der p 1, in the presence or absence of PS-G. Cell surface markers and phagocytic capacity were assessed by FACS analysis, and key polarizing cytokines (IL-12 p40, IL-12 p70, IL-6, IL-23, and IL-10 were quantified. The subsequent regulatory effect of pulsed MD-DCs on naïve T cells was evaluated by determining the T-cell cytokine profile. Results PS-G induced the maturation of MD-DCs and decreased phagocytic capacity, even if pulsed with Der p 1. After incubation with PS-G and Der p 1, MD-DCs produced higher amounts of IL-12 p70, IL-12 p40, IL-6, IL-23, and IL10 than Der p 1-pulsed DCs. Furthermore, type 1 helper T (Th1 cell cytokine (INF-γ production was highly increased when naïve autologous T cells were co-cultured with Der p 1-pulsed MD-DCs. Naïve T cells stimulated by MD-DCs pulsed with Der p 1 failed to produce proliferation of T-cells, whereas the addition of PS-G to Der p 1 induced a significant proliferation of T-cells similar to that observed with PS-G alone. Conclusion The presence of PS-G in an allergen pulse promoted allergic MD-DCs to produce IL-12 p70, IL-12 p40, IL-6, IL-23, and IL-10, and exerted an effect on shifting the immune balance towards Th1 in children with allergic asthma.

  7. Effective Delivery of Antigen-Encapsulin Nanoparticle Fusions to Dendritic Cells Leads to Antigen-Specific Cytotoxic T Cell Activation and Tumor Rejection.

    Science.gov (United States)

    Choi, Bongseo; Moon, Hyojin; Hong, Sung Joon; Shin, Changsik; Do, Yoonkyung; Ryu, Seongho; Kang, Sebyung

    2016-08-23

    In cancer immunotherapy, robust and efficient activation of cytotoxic CD8(+) T cell immune responses is a promising, but challenging task. Dendritic cells (DCs) are well-known professional antigen presenting cells that initiate and regulate antigen-specific cytotoxic CD8(+) T cells that kill their target cells directly as well as secrete IFN-γ, a cytokine critical in tumor rejection. Here, we employed recently established protein cage nanoparticles, encapsulin (Encap), as antigenic peptide nanocarriers by genetically incorporating the OT-1 peptide of ovalbumin (OVA) protein to the three different positions of the Encap subunit. With them, we evaluated their efficacy in activating DC-mediated antigen-specific T cell cytotoxicity and consequent melanoma tumor rejection in vivo. DCs efficiently engulfed Encap and its variants (OT-1-Encaps), which carry antigenic peptides at different positions, and properly processed them within phagosomes. Delivered OT-1 peptides were effectively presented by DCs to naïve CD8(+) T cells successfully, resulting in the proliferation of antigen-specific cytotoxic CD8(+) T cells. OT-1-Encap vaccinations in B16-OVA melanoma tumor bearing mice effectively activated OT-1 peptide specific cytotoxic CD8(+) T cells before or even after tumor generation, resulting in significant suppression of tumor growth in prophylactic as well as therapeutic treatments. A large number of cytotoxic CD8(+) T cells that actively produce both intracellular and secretory IFN-γ were observed in tumor-infiltrating lymphocytes collected from B16-OVA tumor masses originally vaccinated with OT-1-Encap-C upon tumor challenges. The approaches we describe herein may provide opportunities to develop epitope-dependent vaccination systems that stimulate and/or modulate efficient and epitope-specific cytotoxic T cell immune responses in nonpathogenic diseases.

  8. Pharmacological inhibition of eicosanoids and platelet-activating factor signaling impairs zymosan-induced release of IL-23 by dendritic cells.

    Science.gov (United States)

    Rodríguez, Mario; Márquez, Saioa; Montero, Olimpio; Alonso, Sara; Frade, Javier García; Crespo, Mariano Sánchez; Fernández, Nieves

    2016-02-15

    The engagement of the receptors for fungal patterns induces the expression of cytokines, the release of arachidonic acid, and the production of PGE2 in human dendritic cells (DC), but few data are available about other lipid mediators that may modulate DC function. The combined antagonism of leukotriene (LT) B4, cysteinyl-LT, and platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) inhibited IL23A mRNA expression in response to the fungal surrogate zymosan and to a lower extent TNFA (tumor necrosis factor-α) and CSF2 (granulocyte macrophage colony-stimulating factor) mRNA. The combination of lipid mediators and the lipid extract of zymosan-conditioned medium increased the induction of IL23A by LPS (bacterial lipopolysaccharide), thus suggesting that unlike LPS, zymosan elicits the production of mediators at a concentration enough for optimal response. Zymosan induced the release of LTB4, LTE4, 12-hydroxyeicosatetraenoic acid (12-HETE), and PAF C16:0. DC showed a high expression and detectable Ser663 phosphorylation of 5-lipoxygenase in response to zymosan, and a high expression and activity of LPCAT1/2 (lysophosphatidylcholine acyltransferase 1 and 2), the enzymes that incorporate acetate from acetyl-CoA into choline-containing lysophospholipids to produce PAF. Pharmacological modulation of the arachidonic acid cascade and the PAF receptor inhibited the binding of P-71Thr-ATF2 (activating transcription factor 2) to the IL23A promoter, thus mirroring their effects on the expression of IL23A mRNA and IL-23 protein. These results indicate that LTB4, cysteinyl-LT, and PAF, acting through their cognate G protein-coupled receptors, contribute to the phosphorylation of ATF2 and play a central role in IL23A promoter trans-activation and the cytokine signature induced by fungal patterns.

  9. Effects of Reducing Suppressors of Cytokine Signaling-3 (SOCS3 Expression on Dendritic Outgrowth and Demyelination after Spinal Cord Injury.

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    Keun Woo Park

    Full Text Available Suppressors of cytokine signaling-3 (SOCS3 is associated with limitations of nerve growth capacity after injury to the central nervous system. Although genetic manipulations of SOCS3 can enhance axonal regeneration after optic injury, the role of SOCS3 in dendritic outgrowth after spinal cord injury (SCI is still unclear. The present study investigated the endogenous expression of SOCS3 and its role in regulating neurite outgrowth in vitro. Interleukin-6 (IL-6 induces SOCS3 expression at the mRNA and protein levels in neuroscreen-1 (NS-1 cells. In parallel to SOCS3 expression, IL-6 induced tyrosine phosphorylation of signal transducer and activator of transcription 3 (STAT3 in NS-1 cells. Lentiviral delivery of short hairpin RNA (shSOCS3 (Lenti-shSOCS3 to decrease SOCS3 expression into NS-1 cells enhanced IL-6-induced tyrosine phosphorylation of STAT3 (P-STAT3 Tyr705 and promoted neurite outgrowth. In addition, we determined if reduction of SOCS3 expression by microinjection of Lenti-shSOCS3 into spinal cord enhances dendrite outgrowth in spinal cord neurons after SCI. Knocking down of SOCS3 in spinal cord neurons with Lenti-shSOCS3 increased complete SCI-induced P-STAT3 Tyr705. Immunohistochemical analysis showed that complete SCI induced a significant reduction of microtubule association protein 2-positive (MAP-2+ dendrites in the gray and white matter at 1 and 4 weeks after injury. The SCI-induced reduction of MAP-2+ dendrites was inhibited by infection with Lenti-shSOCS3 in areas both rostral and caudal to the lesion at 1 and 4 weeks after complete SCI. Furthermore, shSOCS3 treatment enhanced up-regulation of growth associated protein-43 (GAP-43 expression, which co-localized with MAP-2+ dendrites in white matter and with MAP-2+ cell bodies in gray matter, indicating Lenti-shSOCS3 may induce dendritic regeneration after SCI. Moreover, we demonstrated that Lenti-shSOCS3 decreased SCI-induced demyelination in white matter of spinal cord both

  10. The Idefix enhancer-blocking insulator also harbors barrier activity.

    Science.gov (United States)

    Brasset, E; Hermant, C; Jensen, S; Vaury, C

    2010-01-15

    Chromatin insulators are cis-regulatory sequences participating in the regulation of gene expression. Their presence within the genome is associated with two main functions. One of them is an enhancer-blocking function that blocks enhancer-promoter communication when the insulator is located in between. The second is a boundary or barrier function that insulates independent units of transcription. This latter is observed when two insulators flanking a gene and its regulatory sequences block the regulatory influences of surrounding chromatin. Some years ago, we reported the presence of an insulator within the retrotransposon Idefix from Drosophila melanogaster. This insulator displays an enhancer-blocking activity toward an enhancer located within a second retrotransposon called ZAM. Here, we show that this insulator is not specific to the ZAM enhancer but has the capacity to interfere in the communication established between a broad range of cis-regulatory enhancer and a promoter. Furthermore, we show that, if it is placed on both sides of a transgene, this insulator acts as a barrier able to isolate the transgene from its repressive or enhancing environment. Thus, the Idefix insulator carries both an enhancer-blocking and a barrier activity. According to these properties, the Idefix insulator might prove to be a useful tool to isolate artificial transgenes from positive or negative influences from their integration sites.

  11. MHC class II compartment, endocytosis and phagocytic activity of macrophages and putative dendritic cells isolated from normal tissues rich in synovium.

    Science.gov (United States)

    Moghaddami, Mahin; Mayrhofer, Graham; Cleland, Leslie G

    2005-08-01

    The endocytic and phagocytic activities of a population of MHC IIhi CD11c+ dendritic cell (DC)-like cells in synovium-rich tissues (SRTs) of normal rat paws were compared with CD163+ cells (putative macrophages) from the same tissues and pseudo-afferent lymph DCs, peritoneal macrophages and blood monocytes. Fifty percent of CD11c+ cells and 75% of CD163+ cells isolated from SRT internalized fluorescein-conjugated dextran (FITC-DX). Of these endocytic cells, half of those expressing CD11c, but only 30% of those expressing CD163, were surface MHC class II+ (sMHC II+). CD11c+ cells were more endocytic than monocytes or pseudo-afferent lymph DC, but some CD163+ cells (type A synoviocytes) were found to be highly endocytic. CD163+ cells from SRT were more phagocytic (25%) than the general MHC class II+ population (16%). Of phagocytic cells, 40% of CD163+ cells were sMHC II(variable) and they constituted 60% of all MHC class II+ phagocytic cells. Only 18% of phagocytic MHC II+ cells expressed CD11c and the most of these were MHC IIhi. In comparison, 60% of CD163+ peritoneal macrophages were phagocytic, while blood monocytes were poorly phagocytic. Intracellular MHC class II-rich compartments (MIIC) were prominent in sMHC IIhi cells in SRT but rare in CD163+ cells. Most MHC IIhi CD11c+ cells did not have a detectable MIIC.

  12. Dendritic cell plasticity in tumor-conditioned skin: CD14+ cells at the cross-roads of immune activation and suppression

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    Rieneke evan de Ven

    2013-11-01

    Full Text Available Tumors abuse myeloid plasticity to re-direct dendritic cell (DC differentiation from T cell stimulatory subsets to immune suppressive subsets that can interfere with antitumor immunity. Lined by a dense network of easily accessible DC the skin is a preferred site for the delivery of DC-targeted vaccines. Various groups have recently been focusing on functional aspects of DC subsets in the skin and how these may be affected by tumor-derived suppressive factors. IL-6, Prostaglandin-E2 and IL-10 were identified as factors in cultures of primary human tumors responsible for the inhibited development and activation of skin DC as well as monocyte-derived DC. IL-10 was found to be uniquely able to convert fully developed DC to immature macrophage-like cells with functional M2 characteristics in a physiologically highly relevant skin explant model in which the phenotypic and functional traits of crawl-out DC were studied. Mostly from mouse studies, the JAK2/STAT3 signaling pathway has emerged as a master switch of tumor-induced immune suppression. Our lab has additionally identified p38-MAPK as an important signaling element in human DC suppression, and recently validated it as such in ex vivo cultures of single-cell suspensions from melanoma metastases. Through the identification of molecular mechanisms and signaling events that drive myeloid immune suppression in human tumors, more effective DC-targeted cancer vaccines may be designed.

  13. Evaluation on the Clinical Efifcacy of Dendritic Cell-Activated Cytokine-Induced Killer Cells Combined with Conventional Therapy in the Treatment of Malignant Tumors

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