scholarly journals Clostridial C3 Toxins Enter and Intoxicate Human Dendritic Cells

Toxins ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 563
Author(s):  
Maximilian Fellermann ◽  
Christina Huchler ◽  
Lea Fechter ◽  
Tobias Kolb ◽  
Fanny Wondany ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Stimulated Emission ◽  
Target Cells ◽  
Dependent Manner ◽  
Rho Proteins ◽  
Concentration Dependent Manner ◽  
Monocytic Cells ◽  
Specific Uptake ◽  
Novel Target ◽  
Human Dendritic Cells

C3 protein toxins produced by Clostridium (C.) botulinum and C. limosum are mono-ADP-ribosyltransferases, which specifically modify the GTPases Rho A/B/C in the cytosol of monocytic cells, thereby inhibiting Rho-mediated signal transduction in monocytes, macrophages, and osteoclasts. C3 toxins are selectively taken up into the cytosol of monocytic cells by endocytosis and translocate from acidic endosomes into the cytosol. The C3-catalyzed ADP-ribosylation of Rho proteins inhibits essential functions of these immune cells, such as migration and phagocytosis. Here, we demonstrate that C3 toxins enter and intoxicate dendritic cells in a time- and concentration-dependent manner. Both immature and mature human dendritic cells efficiently internalize C3 exoenzymes. These findings could also be extended to the chimeric fusion toxin C2IN-C3lim. Moreover, stimulated emission depletion (STED) microscopy revealed the localization of the internalized C3 protein in endosomes and emphasized its potential use as a carrier to deliver foreign proteins into dendritic cells. In contrast, the enzyme C2I from the binary C. botulinum C2 toxin was not taken up into dendritic cells, indicating the specific uptake of C3 toxins. Taken together, we identified human dendritic cells as novel target cells for clostridial C3 toxins and demonstrated the specific uptake of these toxins via endosomal vesicles.

scholarly journals Candida albicans Is Phagocytosed, Killed, and Processed for Antigen Presentation by Human Dendritic Cells

2001 ◽  
Vol 69 (11) ◽  
pp. 6813-6822 ◽  
Author(s):  
Simon L. Newman ◽  
Angela Holly
Keyword(s):  
Dendritic Cells ◽  
Candida Albicans ◽  
Invasive Fungal Disease ◽  
Interleukin 4 ◽  
Cell Mediated Immunity ◽  
No Production ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Human Dendritic Cells

ABSTRACT Candida albicans is a component of the normal flora of the alimentary tract and also is found on the mucocutaneous membranes of the healthy host. Candida is the leading cause of invasive fungal disease in premature infants, diabetics, and surgical patients, and of oropharyngeal disease in AIDS patients. As the induction of cell-mediated immunity to Candida is of critical importance in host defense, we sought to determine whether human dendritic cells (DC) could phagocytose and degradeCandida and subsequently present Candidaantigens to T cells. Immature DC obtained by culture of human monocytes in the presence of granulocyte-macrophage colony-stimulating factor and interleukin-4 phagocytosed unopsonized Candida in a time-dependent manner, and phagocytosis was not enhanced by opsonization of Candida in serum. Like macrophages (Mφ), DC recognized Candida by the mannose-fucose receptor. Upon ingestion, DC killed Candida as efficiently as human Mφ, and fungicidal activity was not enhanced by the presence of fresh serum. Although phagocytosis ofCandida by DC stimulated the production of superoxide anion, inhibitors of the respiratory burst (or NO production) did not inhibit killing of Candida, even when phagocytosis was blocked by preincubation of DC with cytochalasin D. Further, although apparently only modest phagolysosomal fusion occurred upon DC phagocytosis of Candida, killing ofCandida under anaerobic conditions was almost equivalent to killing under aerobic conditions. Finally, DC stimulatedCandida-specific lymphocyte proliferation in a concentration-dependent manner after phagocytosis of both viable and heat-killed Candida cells. These data suggest that, in vivo, such interactions between DC and C. albicans may facilitate the induction of cell-mediated immunity.

scholarly journals Cilostazol Suppresses IL-23 Production in Human Dendritic Cells via an AMPK-Dependent Pathway

2016 ◽  
Vol 40 (3-4) ◽  
pp. 499-508 ◽  
Author(s):  
Quanxing Shi ◽  
Zhao Yin ◽  
Peilin Liu ◽  
Bei Zhao ◽  
Zhong Zhang ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Dendritic Cell ◽  
Western Blotting ◽  
Human Monocyte ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Compound C ◽  
Human Dendritic Cells ◽  
Dependent Pathway

Background/Aims: Cilostazol has been previously demonstrated to inhibit IL-23 production in human synovial macrophages via a RhoA/ROCK-dependent pathway. However, whether cilostazol affects IL-23 production in human dendritic cells remains largely unknown. The present study was designed to investigate this question and elucidate the possible underlying mechanisms. Methods: Human monocyte-derived dendritic cells (mo-DCs) were pretreated with or without cilostazol and then incubated with zymosan. Enzyme-linked immunosorbent assay (ELISA) and real time PCR analyses were used to measure IL-23 protein expression and RNA levels, respectively, whereas Western blotting was used to measure the expression and phosphorylation level of AMPK. Results: Our results demonstrated that cilostazol suppressed zymosan-induced IL-23 protein production in a concentration dependent manner without affecting dendritic cell viability. In addition, it was found that cilostazol suppressed the expression of the p19 and p40 subunits of IL-23. Moreover, cilostazol mimicked the effect of the AMPK agonist A-769662, as demonstrated by the fact that IL-23 production was also inhibited by A-769662, and the effect of cilostazol on IL-23 production was blocked by the AMPK antagonist Compound C. More importantly, Western blotting demonstrated that cilostazol led to an increased phosphorylation of AMPK. Conclusion: Collectively, our data suggest that cilostazol inhibits the production of IL-23 in human mo-DCs, potentially via the activation of AMPK. This suggests that cilostazol could be an effective anti-inflammatory agent in IL-23- and dendritic cell-related diseases.

scholarly journals PGE2 Elevates IL-23 Production in Human Dendritic Cells via a cAMP Dependent Pathway

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Quanxing Shi ◽  
Zhao Yin ◽  
Bei Zhao ◽  
Fei Sun ◽  
Haisheng Yu ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Human Monocytes ◽  
Concentration Dependent Manner ◽  
Underlying Mechanisms ◽  
Species Specific ◽  
Human Dendritic Cells ◽  
Dependent Pathway ◽  
Cyclase Activator

PGE2 elevates IL-23 production in mouse dendritic cells while inhibits IL-23 production in isolated human monocytes. Whether this differential effect of PGE2 on IL-23 production is cell-type- or species-specific has not been investigated in detail. The present study was designed to investigate the effect of PGE2 on IL-23 production in human DCs and the possible underlying mechanisms. Human monocytes derived dendritic cells (Mo-DCs) were pretreated with or without PGE2. Then the cells were incubated with zymosan. Our results demonstrated that PGE2 promoted zymosan-induced IL-23 production in a concentration dependent manner. In addition, it was found that PGE2 is also able to elevate MyD88-mediated IL-23 p19 promoter activity. More importantly, ELISA data demonstrated that db-cAMP, a cAMP analog, and forskolin, an adenylate cyclase activator, can mimic the effect of PGE2 on zymosan-induced IL-23 production, and rp-cAMP, a protein kinase A (PKA) inhibitor, can block the effect of PGE2. Moreover, PGE2 can increase zymosan-induced expression of the mRNA levels of both p19 and p40 subunits, which was mimicked by db-cAMP and forskolin. Our data suggest that PGE2 elevates the production of IL-23 in human Mo-DCs via a cAMP dependent pathway.

scholarly journals Human Dendritic Cells Mediate Cellular Apoptosis via Tumor Necrosis Factor–Related Apoptosis-Inducing Ligand (Trail)

1999 ◽  
Vol 190 (8) ◽  
pp. 1155-1164 ◽  
Author(s):  
Neil A. Fanger ◽  
Charles R. Maliszewski ◽  
Ken Schooley ◽  
Thomas S. Griffith
Keyword(s):  
Dendritic Cells ◽  
Tumor Cells ◽  
Cell Types ◽  
Target Cells ◽  
Functional Difference ◽  
Cellular Apoptosis ◽  
Soluble Trail ◽  
Innate Effector ◽  
Human Dendritic Cells ◽  
Necrosis Factor

TRAIL (TNF-related apoptosis-inducing ligand) is a member of the TNF family that induces apoptosis in a variety of cancer cells. In this study, we demonstrate that human CD11c+ blood dendritic cells (DCs) express TRAIL after stimulation with either interferon (IFN)-γ or -α and acquire the ability to kill TRAIL-sensitive tumor cell targets but not TRAIL-resistant tumor cells or normal cell types. The DC-mediated apoptosis was TRAIL specific, as soluble TRAIL receptor blocked target cell death. Moreover, IFN-stimulated interleukin (IL)-3 receptor (R)α+ blood precursor (pre-)DCs displayed minimal cytotoxicity toward the same target cells, demonstrating a clear functional difference between the CD11c+ DC and IL-3Rα+ pre-DC subsets. These results indicate that TRAIL may serve as an innate effector molecule on CD11c+ DCs for the elimination of spontaneously arising tumor cells and suggest a means by which TRAIL-expressing DCs may regulate or eliminate T cells responding to antigen presented by the DCs.

scholarly journals Prostaglandin E2 and Tumor Necrosis Factor α Cooperate to Activate Human Dendritic Cells: Synergistic Activation of Interleukin 12 Production

1997 ◽  
Vol 186 (9) ◽  
pp. 1603-1608 ◽  
Author(s):  
Claudia Rieser ◽  
Günther Böck ◽  
Helmut Klocker ◽  
Georg Bartsch ◽  
Martin Thurnher
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Tumor Necrosis Factor ◽  
Prostaglandin E2 ◽  
Tumor Necrosis ◽  
Interleukin 12 ◽  
Dependent Manner ◽  
Tnf Α ◽  
Human Dendritic Cells ◽  
Necrosis Factor

Interleukin (IL)-12 is a proinflammatory cytokine that contributes to innate resistance and to the development of antigen-specific T cell responses. Among other effects, prostaglandin E2 (PGE2) inhibits the production of IL-12 by macrophages activated with lipopolysaccharide (LPS). Here we investigated the effects of PGE2 on human dendritic cells (DCs) which develop in the presence of GM-CSF and IL-4. We demonstrate that in the absence of LPS, PGE2 dose dependently stimulated the production of IL-12 by DCs. Although PGE2 alone stimulated the production of low amounts of IL-12 only, it synergized with tumor necrosis factor (TNF)-α to induce high levels of IL-12 production by DCs. Addition of TNF-α in the absence of PGE2 had no effect on IL-12 production. Conversely, in the presence of LPS, PGE2 inhibited IL-12 production by DCs in a dose-dependent manner. The combination of PGE2 and TNF-α efficiently silenced mannose receptor–mediated endocytosis in DCs and readily induced neo-expression of the CD83 antigen. In addition, the expression of various surface antigens such as major histocompatibility complex class I and II, adhesion, as well as costimulatory molecules was upregulated by this treatment. The effects of PGE2 on IL-12 synthesis and CD83 expression could be mimicked by dibutyryl-cAMP and forskolin, indicating that they were due to the intracellular elevation of cAMP levels. DC treated with PGE2 and TNF-α were most potent in stimulating allogeneic T cell proliferation. Our data demonstrate that PGE2 contributes to the maturation of human DCs and that PGE2 can be a potent enhancer of IL-12 production by human DCs.

Vibrio parahaemolyticus Flagellin Stimulates the Maturation of Human Monocyte-Derived Dendritic Cells and Elicits Th1-Type Immune Response.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3872-3872
Author(s):  
Hyun-Kyu Kang ◽  
Myong-Suk Park ◽  
Shee-Eun Lee ◽  
Joon-Haeng Rhee ◽  
Jung-Sun Park ◽  
...  
Keyword(s):  
Immune Response ◽  
Dendritic Cells ◽  
Vibrio Parahaemolyticus ◽  
Human Monocyte ◽  
Phenotypic Change ◽  
Target Cells ◽  
Maximal Effect ◽  
Dependent Manner ◽  
Functional Maturation

Abstract Flagellin, the principal component of bacterial flagella, interacts with Toll-like receptor (TLR5) and induces the generation of a pro-inflammation response and activation of host dendritic cells (DCs) in vivo. In this study, we investigated the role of Vibrio parahaemolyticus (V. parahaemolyticus)-derived flagellin as a DC maturation-inducing molecule. V. parahemolyticus-derived flagellin (100–1,000 ng/ml) induced the maturation of human monocyte-derived dendritic cells in a concentration-dependent manner with maximal effect at 500 ng/ml of flagellin as determined by increased levels of surface markers, namely, CD1a, CD80, CD86, CD83, and HLA-DR, a response which could be compared with the phenotypic change in immature DCs (iDCs) treated with lipopolysaccharide (LPS) or cytokine cocktails (CC) with TNF-α, IL-1β, IL-6, and PGE2. Moreover, V. parahaemolyticus-derived flagellin also reduced phagocytic activity, and increased IL-12 production in a polymyxin B-insensitive manner and DC-mediated T cell proliferation, which is comparable with that of LPS- or CC-treated iDCs at several responder to stimulator ratios, suggesting the functional maturation of DCs by V. parahaemolyticus-derived flagellin. Maturation of DCs by V. parahaemolyticus-derived flagellin also elicited a significant increase in specific cytotoxic activity against target cells at several effector to target cells ratios as determined by 51Cr-release assay, and induced Th1-type immune response, such as increase in INF-γ producing cells, determined by ELISPOT assay and analysis of intracellular cytokine staining assay. Taken together, this study demonstrates the role of V. parahaemolyticus-derived flagellin in the functional maturation of DCs, and suggests that V. parahaemolyticus-derived flagellin as a useful molecule for the development of a DC-based immunotherapy against tumors.

scholarly journals The Extracellular Domain of CD83 Inhibits Dendritic Cell–mediated T Cell Stimulation and Binds to a Ligand on Dendritic Cells

2001 ◽  
Vol 194 (12) ◽  
pp. 1813-1821 ◽  
Author(s):  
Matthias Lechmann ◽  
Daniëlle J.E.B. Krooshoop ◽  
Diana Dudziak ◽  
Elisabeth Kremmer ◽  
Christine Kuhnt ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Functional Aspects ◽  
T Cell Stimulation ◽  
Ig Superfamily ◽  
Ig Domain ◽  
Dc Maturation

CD83 is an immunoglobulin (Ig) superfamily member that is upregulated during the maturation of dendritic cells (DCs). It has been widely used as a marker for mature DCs, but its function is still unknown. To approach its potential functional role, we have expressed the extracellular Ig domain of human CD83 (hCD83ext) as a soluble protein. Using this tool we could show that immature as well as mature DCs bind to CD83. Since CD83 binds a ligand also expressed on immature DCs, which do not express CD83, indicates that binding is not a homophilic interaction. In addition we demonstrate that hCD83ext interferes with DC maturation downmodulating the expression of CD80 and CD83, while no phenotypical effects were observed on T cells. Finally, we show that hCD83ext inhibits DC-dependent allogeneic and peptide-specific T cell proliferation in a concentration dependent manner in vitro. This is the first report regarding functional aspects of CD83 and the binding of CD83 to DCs.

scholarly journals Liver X Receptor Agonists Inhibit the Phospholipid Regulatory Gene CTP: Phosphoethanolamine Cytidylyltransferase-Pcyt2

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
Lin Zhu ◽  
Marica Bakovic
Keyword(s):  
Inflammatory Responses ◽  
Regulatory Gene ◽  
Liver X Receptor ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Protein Levels ◽  
Kennedy Pathway ◽  
Mrna And Protein Expression ◽  
Novel Target ◽  
Lxr Agonists

Metabolic pulse-chase experiments demonstrated that 25-hydroxycholesterol (25-OH), the endogenous activator of the liver X receptor (LXR), significantly reduced the biosynthesis of phosphatidylethanolamine via CDP-ethanolamine (Kennedy) pathway at the step catalyzed by CTP: phosphoethanolamine cytidylyltransferase (Pcyt2). In the mouse embryonic fibroblasts C3H10T1/2, the LXR synthetic agonist TO901317 lowered Pcyt2 promoter-luciferase activity in a concentration-dependent manner. Furthermore, 25-OH and TO901317 reduced mouse Pcyt2 mRNA and protein levels by 35–60%. The inhibitory effects of oxysterols and TO901317 on the Pcyt2 promoter function, mRNA and protein expression were conserved in the human breast cancer cells MCF-7. These studies identify the Pcyt2 gene as a novel target whereby LXR agonists may indirectly modulate inflammatory responses and atherosclerosis.

scholarly journals Measles Virus Transmission from Dendritic Cells to T Cells: Formation of Synapse-Like Interfaces Concentrating Viral and Cellular Components

2012 ◽  
Vol 86 (18) ◽  
pp. 9773-9781 ◽  
Author(s):  
Susanne Koethe ◽  
Elita Avota ◽  
Sibylle Schneider-Schaulies
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Measles Virus ◽  
Virus Transmission ◽  
Actin Dynamics ◽  
Target Cells ◽  
Dependent Manner ◽  
Viral Glycoprotein ◽  
Glycoprotein H ◽  
Cellular Components

Transmission of measles virus (MV) to T cells by its early CD150+target cells is considered to be crucial for viral dissemination within the hematopoietic compartment. Using cocultures involving monocyte-derived dendritic cells (DCs) and T cells, we now show that T cells acquire MV most efficiently fromcis-infected DCs rather than DCs having trapped MV (trans-infection). Transmission involves interactions of the viral glycoprotein H with its receptor CD150 and is therefore more efficient to preactivated T cells. In addition to rare association with actin-rich filopodial structures, the formation of contact interfaces consistent with that of virological synapses (VS) was observed where viral proteins accumulated and CD150 was redistributed in an actin-dependent manner. In addition to these molecules, activated LFA-1, DC-SIGN, CD81, and phosphorylated ezrin-radixin-moesin proteins, which also mark the HIV VS, redistributed toward the MV VS. Most interestingly, moesin and substance P receptor, both implicated earlier in assisting MV entry or cell-to-cell transmission, also partitioned to the transmission structure. Altogether, the MV VS shares important similarities to the HIV VS in concentrating cellular components potentially regulating actin dynamics, conjugate stability, and membrane fusion as required for efficient entry of MV into target T cells.

scholarly journals Lysine and Polyamines Are Substrates for Transglutamination of Rho by the BordetellaDermonecrotic Toxin

2001 ◽  
Vol 69 (12) ◽  
pp. 7663-7670 ◽  
Author(s):  
Gudula Schmidt ◽  
Udo-Michael Goehring ◽  
Joerg Schirmer ◽  
Sandrine Uttenweiler-Joseph ◽  
Matthias Wilm ◽  
...  
Keyword(s):  
Rho Gtpases ◽  
Affinity Purification ◽  
Dependent Manner ◽  
Rho Proteins ◽  
Concentration Dependent Manner ◽  
Gtp Hydrolysis ◽  
Dermonecrotic Toxin ◽  
Hydrolysis Of ◽  
Active Fragment

ABSTRACT Bordetella dermonecrotic toxin (DNT) catalyzes the transglutamination of glutamine-63/61 of Rho GTPases, thereby constitutively activating Rho proteins. Here we identified second substrates for transglutamination of RhoA by DNT. The enzymatically active fragment of DNT (residues 1136 to 1451, ΔDNT) induced the incorporation of l-[14C]lysine in RhoA in a concentration-dependent manner. Also, Rac and Cdc42, but not Ras, were transglutaminated with lysine by ΔDNT. Transglutamination of the GTPase with l-lysine inhibited intrinsic and Rho-GAP-stimulated GTP hydrolysis of RhoA. In contrast to lysine, treatment of RhoA with alanine, arginine, and glutamine were not able to substitute for lysine in the transglutamination reaction. DNT increased the incorporation of l-[14C]lysine into embryonic bovine lung cells. Microinjection of GST-RhoA together with the enzymatically active DNT fragment intoXenopus oocytes, subsequent affinity purification of modified GST-RhoA, and mass spectrometry identified attachment of putrescine or spermidine at glutamine-63 of RhoA. A comparison of putrescine, spermidine, and lysine as substrates for DNT-induced transglutamination of RhoA revealed that lysine is a preferred second substrate at least in vitro.

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