Immunosuppressive Drugs up-Regulate the Immunoinhibitory Receptor Osteoactivin On Human Monocyte-Derived Dendritic Cells

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3284-3284
Author(s):  
Sabine Braun ◽  
Michael Gutknecht ◽  
Mark-Alexander Schwarzbich ◽  
Lothar Kanz ◽  
Helmut R Salih ◽  
...  

Abstract Abstract 3284 Introduction: Dendritic cells (DC) abundantly express the type I transmembrane glycoprotein Osteoactivin (OA) - also known as transmembrane glycoprotein NMB and DC-HIL - compared to low expression levels on monocytes. Antigen-presenting cells interact via OA with the type I transmembrane proteoglycan syndecan-4 (SD-4) on T cells which inhibits T cell activation. We previously reported on increased expression of OA upon exposure of monocyte-derived DC (moDC) to immunosuppressive drugs (e.g., Gutknecht et al ASH annual meeting 2011). Here we extended these analyses and comparatively analyzed the impact of various immunsuppressive drugs (ID) on moDC phenotype and function. Methods: The moDC were generated from blood monocytes by plastic adherence and exposure to GM-CSF and IL-4. Clinically relevant concentrations of ID were added to the culture medium every second day starting with the first day of culture (cyclosporine A: 1μg/ml, prednisolone: 3.5μg/ml, tacrolimus: 10ng/ml, mycophenolat-mofetil 0.1μM, methotrexat 230ng/ml). Cells were harvested for immunophenotyping by flow cytometry, western-blotting and real-time PCR. Cytokine release by moDC was determined on day 7 by ELISA. Functional properties were determined by mixed lymphocyte reactions (MLR) on day 7 of culture. Results: Exposure of moDC to therapeutic concentrations of prednisolone resulted in significantly reduced expression of the costimulatory molecules CD83 and CD86 and increased levels of the monocyte marker CD14, indicative of impaired differentiation. Tacrolimus significantly increased CD14 expression and reduced CD83 expression, while the other ID did not cause significant alterations. All ID altered the release of the immunomodulatory cytokines IL-10, IL-6 and TGF-ß. Notably, all ID except cyclosporine A caused a substantial upregulation of the immunoinhibitory receptor OA in moDC. The extent of OA expression increased over time of exposure to ID during differentiation and resulted in reduced capacity of the moDC to stimulate allogenic T cells which could be restored by disruption of OA/SD-4 interaction using a blocking OA antibody. Conclusion: Increased expression of OA on moDC upon exposure to ID contributes to inhibition of T-cell activation. The mechanisms underlying the differential effect of cyclosporine A are presently under study. Our results indicate that targeting OA/SD-4 interaction may hold promise for modulation of T cell responses in various pathophysiological conditions and immunotherapeutic strategies. Disclosures: No relevant conflicts of interest to declare.

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3232-3232
Author(s):  
Mark-Alexander Schwarzbich ◽  
Michael Gutknecht ◽  
Lisa Guettler ◽  
Lothar Kanz ◽  
Helmut R. Salih ◽  
...  

Abstract Abstract 3232 Osteoactivin, also known as transmembrane glycoprotein NMB (GPNMB) and dendritic cell-associated transmembrane protein (DC-HIL), is a type I transmembrane glycoprotein that is detected abundantly in dendritic cells (DC), but not or only at low levels in monocytes. Its expression on antigen-presenting cells (APC) can inhibit T cell activation by binding the type I transmembrane proteoglycan syndecan-4 (SD-4) on T cells. We here studied the influence of different therapeutically used immunosuppressive agents such as the corticosteroid prednisolone and the calcineurin inhibitors tacrolimus or cyclosporine A on the expression of osteoactivin in human monocyte-derived DC. Therefore, DC were generated from blood monocytes isolated by plastic adherence and exposed to GM-CSF and IL-4. Prednisolone, tacrolimus or cyclosporine A were added to the culture medium at concentrations obtained upon clinical application in patients (cyclosporine A: 1μg/ml, prednisolone: 3.5μg/ml, tacrolimus: 10ng/ml) every second day starting from the first day of culture. Cells were harvested for immunophenotyping and osteoactivin expression analysis by immunostaining, western-blotting and real-time RT-PCR or for functional analyses in mixed lymphocyte reactions (MLR) on day 7 of culture. DC generated in the presence of therapeutic concentrations of the immunosuppressant drugs showed a reduced expression of CD1a. Furthermore, we observed a clear upregulation of osteoactivin on DC that had been treated with the immunosuppressive agents. In line with osteoactivin up-regulation, exposure to the immunosuppressive drugs resulted in reduced stimulatory capacity of the DC in MLR with allogenic T cells, and this could be restored by addition of blocking osteoactivin antibody. In summary, our results demonstrate that upregulation of osteoactivin is critically involved in the inhibition of DC function upon exposure to different classes of immunosuppressive agents. These findings suggest that upregulation of osteoactivin in DC constitutes a ubiquitous mechanism that may underlie inhibition of T cell activation by these drugs. Disclosures: No relevant conflicts of interest to declare.


2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Song Chen ◽  
Ran Ding ◽  
Yan Zhou ◽  
Xian Zhang ◽  
Rui Zhu ◽  
...  

YCP, as a kind of natural polysaccharides from the mycelium of marine filamentous fungusPhoma herbarumYS4108, has great antitumor potentialviaenhancement of host immune response, but little is known about the molecular mechanisms. In the present study, we mainly focused on the effects and mechanisms of YCP on the specific immunity mediated by dendritic cells (DCs) and T cells. T cell /DC activation-related factors including interferon- (IFN-)γ, interleukin-12 (IL-12), and IL-4 were examined with ELISA. Receptor knock-out mice and fluorescence-activated cell sorting are used to analyze the YCP-binding receptor of T cells and DCs. RT-PCR is utilized to measure MAGE-A3 for analyzing the tumor-specific killing effect. In our study, we demonstrated YCP can provide the second signal for T cell activation, proliferation, and IFN-γproduction through binding to toll-like receptor- (TLR-) 2 and TLR-4. YCP could effectively promote IL-12 secretion and expression of markers (CD80, CD86, and MHC II)viaTLR-4 on DCs. Antigen-specific immunity against mouse melanoma cells was strengthened through the activation of T cells and the enhancement of capacity of DCs by YCP. The data supported that YCP can exhibit specific immunomodulatory capacity mediated by T cells and DCs.


2021 ◽  
Vol 478 (22) ◽  
pp. 3999-4004
Author(s):  
Lawrence P. Kane

Tim-3 is a transmembrane protein that is highly expressed on subsets of chronically stimulated CD4+ helper and CD8+ cytotoxic T cells, with more transient expression during acute activation and infection. Tim-3 is also constitutively expressed by multiple types of myeloid cells. Like other TIM family members, Tim-3 can bind to phosphatidylserine displayed by apoptotic cells, and this interaction has been shown to mediate uptake of such cells by dendritic cells and cross-presentation of antigens to CD8+ T cells. In contrast, how the recognition of PS by Tim-3 might regulate the function of Tim-3+ T cells is not known. In their recent paper, Lemmon and colleagues demonstrate for the first time that recognition of PS by Tim-3 leads to enhanced T cell activation.


2020 ◽  
Author(s):  
Yunkai Wang ◽  
Jie Wang ◽  
Lu Han ◽  
Yun Li Shen ◽  
Jie Yun You ◽  
...  

Abstract Background: Triggering receptor expressed on myeloid cells (TREM)-1is identified as a major upstream proatherogenic receptor. However, the cellular processes modulated by TREM-1 in the development of atherosclerosis and plaque destabilization has not been fully elucidated. In this study, we investigated the effects of TREM-1 on dendritic cell maturation and dendritic cell–mediated T-cell activation induced by oxidized low-density lipoprotein (ox-LDL) in atherogenesis. Methods: Human peripheral blood monocytes were differentiated to dendritic cells and stimulated by ox-LDL. Naive autologous T cells were co-cultured with pretreated dendritic cells.The expressionof TREM-1 and the production of inflammatory cytokines were assessed by real-time PCR, western blot and ELISA.The expression of immune factors was determined with FACS to evaluate dendritic cell maturation and T-cell activation. Results: Stimulation with ox-LDL promoted dendritic cell maturation, TREM-1 expression and T-cell activation, and exposure of T cells to ox-LDL-treated dendritic cells induced production of interferon-γ and IL-17. Blocking TREM-1 suppressed dendritic cell maturation with low expression of CD1a, CD40, CD86 and HLA-DR, decreased production of TNF-α, IL-1β, IL-6 and MCP-1, and increased secretion of TGF-β and IL-10. In addition, stimulation of ox-LDL induced miR-155, miR-27, Let-7c and miR-185 expression, whereas inhibition of TREM-1 repressed miRNA-155. Silencing TREM-1 or miRNA-155 increased SOCS1 expression induced by ox-LDL. T cells derived from carotid atherosclerotic plaques or healthy individuals showed similar result patterns. Conclusion: These data suggest that TREM-1 modulates maturation of dendritic cells and activation of plaque T cells induced by ox-LDL, a pivotal player in atherogenesis.


2020 ◽  
Vol 8 (2) ◽  
pp. e001521
Author(s):  
Javier Arranz-Nicolás ◽  
Miguel Martin-Salgado ◽  
Cristina Rodríguez-Rodríguez ◽  
Rosa Liébana ◽  
Maria C Moreno-Ortiz ◽  
...  

BackgroundThe inhibitory functions triggered by the programmed cell death-1 (PD-1) receptor following binding to its ligand (PD-L1) protect healthy organs from cytotoxic T cells, and neutralize antitumor T cell attack. Antibody-based therapies to block PD-1/PD-L1 interaction have yielded notable results, but most patients eventually develop resistance. This failure is attributed to CD8+ T cells achieving hyporesponsive states from which recovery is hardly feasible. Dysfunctional T cell phenotypes are favored by a sustained imbalance in the diacylglycerol (DAG)- and Ca2+-regulated transcriptional programs. In mice, DAG kinase ζ (DGKζ) facilitates DAG consumption, limiting T cell activation and cytotoxic T cell responses. DGKζ deficiency facilitates tumor rejection in mice without apparent adverse autoimmune effects. Despite its therapeutic potential, little is known about DGKζ function in human T cells, and no known inhibitors target this isoform.MethodsWe used a human triple parameter reporter cell line to examine the consequences of DGKζ depletion on the transcriptional restriction imposed by PD-1 ligation. We studied the effect of DGKζ deficiency on PD-1 expression dynamics, as well as the impact of DGKζ absence on the in vivo growth of MC38 adenocarcinoma cells.ResultsWe demonstrate that DGKζ depletion enhances DAG-regulated transcriptional programs, promoting interleukin-2 production and partially counteracting PD-1 inhibitory functions. DGKζ loss results in limited PD-1 expression and enhanced expansion of cytotoxic CD8+ T cell populations. This is observed even in immunosuppressive milieus, and correlates with the reduced ability of MC38 adenocarcinoma cells to form tumors in DGKζ-deficient mice.ConclusionsOur results, which define a role for DGKζ in the control of PD-1 expression, confirm DGKζ potential as a therapeutic target as well as a biomarker of CD8+ T cell dysfunctional states.


2019 ◽  
Vol 11 (2) ◽  
pp. 108-123
Author(s):  
Dan Tong ◽  
Li Zhang ◽  
Fei Ning ◽  
Ying Xu ◽  
Xiaoyu Hu ◽  
...  

Abstract Common γ chain cytokines are important for immune memory formation. Among them, the role of IL-2 remains to be fully explored. It has been suggested that this cytokine is critically needed in the late phase of primary CD4 T cell activation. Lack of IL-2 at this stage sets for a diminished recall response in subsequent challenges. However, as IL-2 peak production is over at this point, the source and the exact mechanism that promotes its production remain elusive. We report here that resting, previously antigen-stimulated CD4 T cells maintain a minimalist response to dendritic cells after their peak activation in vitro. This subtle activation event may be induced by DCs without overt presence of antigen and appears to be stronger if IL-2 comes from the same dendritic cells. This encounter reactivates a miniature IL-2 production and leads a gene expression profile change in these previously activated CD4 T cells. The CD4 T cells so experienced show enhanced reactivation intensity upon secondary challenges later on. Although mostly relying on in vitro evidence, our work may implicate a subtle programing for CD4 T cell survival after primary activation in vivo.


Blood ◽  
2006 ◽  
Vol 107 (3) ◽  
pp. 1010-1017 ◽  
Author(s):  
Peta J. O'Connell ◽  
Xiangbin Wang ◽  
Matilde Leon-Ponte ◽  
Corrie Griffiths ◽  
Sandeep C. Pingle ◽  
...  

AbstractAdaptive immunity is triggered at the immune synapse, where peptide-major histocompatibility complexes and costimulatory molecules expressed by dendritic cells (DCs) are physically presented to T cells. Here we describe transmission of the inflammatory monoamine serotonin (5-hydroxytryptamine [5-HT]) between these cells. DCs take up 5-HT from the microenvironment and from activated T cells (that synthesize 5-HT) and this uptake is inhibited by the antidepressant, fluoxetine. Expression of 5-HT transporters (SERTs) is regulated by DC maturation, exposure to microbial stimuli, and physical interactions with T cells. Significantly, 5-HT sequestered by DCs is stored within LAMP-1+ vesicles and subsequently released via Ca2+-dependent exocytosis, which was confirmed by amperometric recordings. In turn, extracellular 5-HT can reduce T-cell levels of cAMP, a modulator of T-cell activation. Thus, through the uptake of 5-HT at sites of inflammation, and from activated T cells, DCs may shuttle 5-HT to naive T cells and thereby modulate T-cell proliferation and differentiation. These data constitute the first direct measurement of triggered exocytosis by DCs and reveal a new and rapid type of signaling that may be optimized by the intimate synaptic environment between DCs and T cells. Moreover, these results highlight an important role for 5-HT signaling in immune function and the potential consequences of commonly used drugs that target 5-HT uptake and release.


2018 ◽  
Vol 92 (8) ◽  
Author(s):  
E. Kip ◽  
J. Staal ◽  
L. Verstrepen ◽  
H. G. Tima ◽  
S. Terryn ◽  
...  

ABSTRACTMALT1 is involved in the activation of immune responses, as well as in the proliferation and survival of certain cancer cells. MALT1 acts as a scaffold protein for NF-κB signaling and a cysteine protease that cleaves substrates, further promoting the expression of immunoregulatory genes. Deregulated MALT1 activity has been associated with autoimmunity and cancer, implicating MALT1 as a new therapeutic target. Although MALT1 deficiency has been shown to protect against experimental autoimmune encephalomyelitis, nothing is known about the impact of MALT1 on virus infection in the central nervous system. Here, we studied infection with an attenuated rabies virus, Evelyn-Rotnycki-Abelseth (ERA) virus, and observed increased susceptibility with ERA virus in MALT1−/−mice. Indeed, after intranasal infection with ERA virus, wild-type mice developed mild transient clinical signs with recovery at 35 days postinoculation (dpi). Interestingly, MALT1−/−mice developed severe disease requiring euthanasia at around 17 dpi. A decreased induction of inflammatory gene expression and cell infiltration and activation was observed in MALT1−/−mice at 10 dpi compared to MALT1+/+infected mice. At 17 dpi, however, the level of inflammatory cell activation was comparable to that observed in MALT1+/+mice. Moreover, MALT1−/−mice failed to produce virus-neutralizing antibodies. Similar results were obtained with specific inactivation of MALT1 in T cells. Finally, treatment of wild-type mice with mepazine, a MALT1 protease inhibitor, also led to mortality upon ERA virus infection. These data emphasize the importance of early inflammation and activation of T cells through MALT1 for controlling the virulence of an attenuated rabies virus in the brain.IMPORTANCERabies virus is a neurotropic virus which can infect any mammal. Annually, 59,000 people die from rabies. Effective therapy is lacking and hampered by gaps in the understanding of virus pathogenicity. MALT1 is an intracellular protein involved in innate and adaptive immunity and is an interesting therapeutic target because MALT1-deregulated activity has been associated with autoimmunity and cancers. The role of MALT1 in viral infection is, however, largely unknown. Here, we study the impact of MALT1 on virus infection in the brain, using the attenuated ERA rabies virus in different models of MALT1-deficient mice. We reveal the importance of MALT1-mediated inflammation and T cell activation to control ERA virus, providing new insights in the biology of MALT1 and rabies virus infection.


Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 300 ◽  
Author(s):  
Konstantina Antoniou ◽  
Fanny Ender ◽  
Tillman Vollbrandt ◽  
Yves Laumonnier ◽  
Franziska Rathmann ◽  
...  

Activation of the C5/C5a/C5a receptor 1 (C5aR1) axis during allergen sensitization protects from maladaptive T cell activation. To explore the underlying regulatory mechanisms, we analyzed the impact of C5aR1 activation on pulmonary CD11b+ conventional dendritic cells (cDCs) in the context of house-dust-mite (HDM) exposure. BALB/c mice were intratracheally immunized with an HDM/ovalbumin (OVA) mixture. After 24 h, we detected two CD11b+ cDC populations that could be distinguished on the basis of C5aR1 expression. C5aR1− but not C5aR1+ cDCs strongly induced T cell proliferation of OVA-reactive transgenic CD4+ T cells after re-exposure to antigen in vitro. C5aR1− cDCs expressed higher levels of MHC-II and CD40 than their C5aR1+ counterparts, which correlated directly with a higher frequency of interactions with cognate CD4+ T cells. Priming of OVA-specific T cells by C5aR1+ cDCs could be markedly increased by in vitro blockade of C5aR1 and this was associated with increased CD40 expression. Simultaneous blockade of C5aR1 and CD40L on C5aR1+ cDCs decreased T cell proliferation. Finally, pulsing with OVA-induced C5 production and its cleavage into C5a by both populations of CD11b+ cDCs. Thus, we propose a model in which allergen-induced autocrine C5a generation and subsequent C5aR1 activation in pulmonary CD11b+ cDCs promotes tolerance towards aeroallergens through downregulation of CD40.


2003 ◽  
Vol 10 (1) ◽  
pp. 61-65 ◽  
Author(s):  
L. Frasca ◽  
C. Scottà ◽  
G. Lombardi ◽  
E. Piccolella

T cell suppression is a well established phenomenon, but the mechanisms involved are still a matter of debate. Mouse anergic T cells were shown to suppress responder T cell activation by inhibiting the antigen presenting function of DC. In the present work we studied the effects of co-culturing human anergic CD4+T cells with autologous dendritic cells (DC) at different stages of maturation. Either DC maturation or survival, depending on whether immature or mature DC where used as APC, was impaired in the presence of anergic cells. Indeed, MHC and costimulatory molecule up-regulation was inhibited in immature DC, whereas apoptotic phenomena were favored in mature DC and consequently in responder T cells. Defective ligation of CD40 by CD40L (CD154) was responsible for CD95-mediated and spontaneous apoptosis of DC as well as for a failure of their maturation process. These findings indicate that lack of activation of CD40 on DC by CD40L-defective anergic cells might be the primary event involved in T cell suppression and support the role of CD40 signaling in regulating both activation and survival of DC.


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