scholarly journals Thrombospondin 1 Is an Autocrine Negative Regulator of Human Dendritic Cell Activation

2003 ◽  
Vol 198 (8) ◽  
pp. 1277-1283 ◽  
Author(s):  
Virginie Doyen ◽  
Manuel Rubio ◽  
Deborah Braun ◽  
Toshiaru Nakajima ◽  
Jun Abe ◽  
...  
Keyword(s):  
Steady State ◽  
Cell Activation ◽  
Cytokine Production ◽  
Transforming Growth Factor ◽  
Human Monocyte ◽  
Negative Regulator ◽  
Dendritic Cell Activation ◽  
Tnf Α ◽  
Thrombospondin 1

Thrombospondin 1 (TSP) elicits potent antiinflammatory activities in vivo, as evidenced by persistent, multiorgan inflammation in TSP null mice. Herein, we report that DCs represent an abundant source of TSP at steady state and during activation. Human monocyte-derived immature dendritic cells (iDCs) spontaneously produce TSP, which is strongly enhanced by PGE2 and to a lesser extent by transforming growth factor (TGF) β, two soluble mediators secreted by macrophages after engulfment of damaged tissues. Shortly after activation via danger signals, DCs transiently produce interleukin (IL) 12 and tumor necrosis factor (TNF) α, thereby eliciting protective and inflammatory immune responses. Microbial stimuli increase TSP production, which is further enhanced by IL-10 or TGF-β. The endogenous TSP produced during early DC activation negatively regulates IL-12, TNF-α, and IL-10 release through its interactions with CD47 and CD36. After prolonged activation, DCs extinguish their cytokine synthesis and become refractory to subsequent stimulation, thereby favoring the return to steady state. Such “exhausted” DCs continue to release TSP but not IL-10. Disrupting TSP–CD47 interactions during their restimulation restores their cytokine production. We conclude that DC-derived TSP serves as a previously unappreciated negative regulator contributing to arrest of cytokine production, further supporting its fundamental role in vivo in the active resolution of inflammation and maintenance of steady state.

scholarly journals Dendritic Cell Activation and Cytokine Production Induced by Group B Neisseria meningitidis: Interleukin-12 Production Depends on Lipopolysaccharide Expression in Intact Bacteria

2001 ◽  
Vol 69 (7) ◽  
pp. 4351-4357 ◽  
Author(s):  
Garth L. J. Dixon ◽  
Phillippa J. Newton ◽  
Benjamin M. Chain ◽  
David Katz ◽  
Svein Rune Andersen ◽  
...  
Keyword(s):  
Neisseria Meningitidis ◽  
Parent Strain ◽  
Cell Activation ◽  
Cytokine Production ◽  
Costimulatory Molecules ◽  
Interleukin 12 ◽  
Dendritic Cell Activation ◽  
Tnf Α ◽  
High Level ◽  
Dc Maturation

ABSTRACT Interactions between dendritic cells (DCs) and microbial pathogens are fundamental to the generation of innate and adaptive immune responses. Upon stimulation with bacteria or bacterial components such as lipopolysaccharide (LPS), immature DCs undergo a maturation process that involves expression of costimulatory molecules, HLA molecules, and cytokines and chemokines, thus providing critical signals for lymphocyte development and differentiation. In this study, we investigated the response of in vitro-generated human DCs to a serogroup B strain of Neisseria meningitidis compared to an isogenic mutant lpxA strain totally deficient in LPS and purified LPS from the same strain. We show that the parent strain,lpxA mutant, and meningococcal LPS all induce DC maturation as measured by increased surface expression of costimulatory molecules and HLA class I and II molecules. Both the parent and lpxAstrains induced production of tumor necrosis factor alpha (TNF-α), interleukin-1α (IL-1α), and IL-6 in DCs, although the parent was the more potent stimulus. In contrast, high-level IL-12 production was only seen with the parent strain. Compared to intact bacteria, purified LPS was a very poor inducer of IL-1α, IL-6, and TNF-α production and induced no detectable IL-12. Addition of exogenous LPS to thelpxA strain only partially restored cytokine production and did not restore IL-12 production. These data show that non-LPS components of N. meningitidis induce DC maturation, but that LPS in the context of the intact bacterium is required for high-level cytokine production, especially that of IL-12. These findings may be useful in assessing components of N. meningitidis as potential vaccine candidates.

scholarly journals Mycobacterium tuberculosis 19-Kilodalton Lipoprotein Inhibits Mycobacterium smegmatis-Induced Cytokine Production by Human Macrophages In Vitro

2001 ◽  
Vol 69 (3) ◽  
pp. 1433-1439 ◽  
Author(s):  
Frank A. Post ◽  
Claudia Manca ◽  
Olivier Neyrolles ◽  
Bernhard Ryffel ◽  
Douglas B. Young ◽  
...  
Keyword(s):  
T Cell Activation ◽  
Cell Activation ◽  
Cytokine Production ◽  
Human Monocyte ◽  
Interleukin 12 ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Factor Alpha ◽  
Necrosis Factor

ABSTRACT Vaccination of mice with Mycobacterium vaccae orM. smegmatis induces some protection against M. tuberculosis challenge. The 19-kDa lipoprotein of M. tuberculosis, expressed in M. vaccae or M. smegmatis (M. smeg19kDa), abrogates this protective immunity. To investigate the mechanism of this suppression of immunity, human monocyte-derived macrophages (MDM) were infected with M. smeg19kDa. Infection resulted in reduced production of tumor necrosis factor alpha (TNF-α) (P < 0.01), interleukin-12 (IL-12) (P < 0.05), IL-6 (P < 0.05), and IL-10 (P < 0.05), compared to infection with M. smegmatis vector (M. smegV). Infection with M. smeg19kDa and with M. smegV had no differential effect on expression of costimulatory molecules on MDM, nor did it affect the proliferation of presensitized T cells cocultured with infected MDM. When MDM were infected withM. smegmatis expressing mutated forms of the 19-kDa lipoprotein, including non-O-glycosylated (M. smeg19NOG), nonsecreted (M. smeg19NS), and nonacylated (M. smeg19NA) variants, the reduced production of TNF-α or IL-12 was not observed. When the purified 19-kDa lipoprotein was added directly to cultures of infected monocytes, there was little effect on either induction of cytokine production or its inhibition. Thus, the immunosuppressive effect is dependent on glycosylated and acylated 19-kDa lipoprotein present in the phagosome containing the mycobacterium. These results suggest that the diminished protection against challenge with M. tuberculosis seen in mice vaccinated with M. smegmatis expressing the 19-kDa lipoprotein is the result of reduced TNF-α and IL-12 production, possibly leading to reduced induction of T-cell activation.

Mir-146a and Mir-146b Regulate Human Dendritic Cell Apoptosis and Cytokine Production By Targeting of TRAF6 and IRAK1

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4118-4118
Author(s):  
Haein Park ◽  
Xin Huang ◽  
Changming Lu ◽  
Mitchell S. Cairo ◽  
Xianzheng Zhou
Keyword(s):  
Dendritic Cell ◽  
Cytokine Production ◽  
Conflicts Of Interest ◽  
Annexin V ◽  
Human Monocyte ◽  
Negative Regulator ◽  
P Value ◽  
Monocyte Differentiation ◽  
Tnf Α ◽  
Dc Maturation

Abstract MicroRNA (miRNA) regulation of dendritic cell (DC) development and function is not fully understood. We have previously reported 27 differentially expressed miRNAs during human monocyte differentiation into immature DCs (imDCs) and mature DCs (mDCs). Here, we aimed at uncovering the functional role of miR-146a and miR-146b (miR-146a/b) during this differentiation process. To investigate miR-146a and miR-146b expression during human monocyte differentiation into imDCs and mDCs, monocytes were differentiated into imDCs with GM-CSF and IL-4 and matured with IL-1β, IL-6, TNF-α, and PGE2. We found by qRT-PCR that expression of miR-146a/b was dramatically increased upon monocyte differentiation into imDCs (miR-146a, 10-fold; miR-146b, 37-fold at day6; n=4; p value of Student t test<0.05) and mDCs (miR-146a, 51-fold; miR-146b, 79-fold; n=4; p<0.005). Up-regulation of miR-146a/b in mDCs was predominantly mediated by IL-1β but not IL-6, TNF-a, or PGE2 (n=3; p<0.01). DC apoptosis is important for self-tolerance and immunity. We then evaluated the effect of altering miR-146a/b expression levels on DC apoptosis by Annexin V/PI staining. Silencing of miR-146a, miR-146b or both in imDCs (Fig. 1A) and mDCs significantly prevented DC from apoptosis (Fig. 1A; miR-146a, 24%±3.1; miR-146b, 26%±1.7; miR-146a/b; 23%±2.8 vs control, 46%±2.3 of Annexin V+ populations; n=8; p<0.005) whereas overexpression of miR-146a, miR-146b or both in imDCs (Fig. 1B) and mDCs significantly increased the proportion of apoptotic cells (Fig. 1B; 46%±1.9, 47%±2.1, 45%±2.3 vs 36%±3.3; n=6; p<0.05). These results indicate that miR-146a/b may function as pro-apoptotic regulators during human monocyte differentiation into imDCs and mDCs. It is known that the NF-κB pathway regulates DC development, function and survival, and that TRAF6 and IRAK1 are major signal transducers in the NF-κB pathway. In addition, both TRAF6 and IRAK1 are known target genes of miR-146a. Indeed, miR-146a/b expression in imDCs and mDCs was inversely correlated with TRAF6 and IRAK1 mRNA and protein expression (n=4; p<0.05). Furthermore, siRNA silencing of TRAF6 and/or IRAK1 in imDCs and mDCs significantly enhanced DC apoptosis (n=4; p<0.05). By contrast, lentivirus overexpression of TRAF6 and/or IRAK1 promoted DC survival compared to control lentivirus transduced cells (n=2; p<0.05). To confirm that miR-146a/b-induced human DC apoptosis is involved in suppression of the NF-κB pathway, at least in part through down regulation of the NF-κB signaling transducers TRAF6 and IRAK1, we examined the protein level of IκB as a negative regulator of NF-κB and Bcl-2 as a known downstream anti-apoptotic molecule of the NF-κB pathway. Silencing of miR-146a/b in imDCs and mDCs significantly decreased IκBα and increased Bcl-2 expression whereas overexpression of miR-146a and/or miR-146b or silencing of TRAF6 and/or IRAK1 significantly increased IκBα and decreased Bcl-2 expression in imDCs and mDCs (n=4; p<0.01). These results indicate that miR-146a/b modulate DC apoptosis through inhibition of NF-κB activation via targeting TRAF6 and IRAK1. Next, we investigated whether miR-146a/b regulates pro-inflammatory cytokine production in DCs. We found that IL-12p70, IL-6 and TNF-α production were significantly enhanced after miR-146 and/or miR-146b silencing during DC maturation (n≥2; p<0.05), although altering miR-146a/b expression had little effect on DC maturation (n=6). By contrast, IL-12p70, IL-6 and TNF-α production was highly reduced after miR-146a and/or miR-146b overexpression (n≥2; p<0.05). In conclusion, we have demonstrated three important findings in this report. First, expression of both miR-146a and miR-146b is up-regulated during human monocyte differentiation into imDCs and mDCs. Secondly, although miR-146a and miR-146b do not appear to play a role in DC maturation, they may be critical regulators of DC apoptosis and cytokine production. Thirdly, mechanistically, miR-146a/b targets TRAF6 and IRAK1, leading to inhibition of NF-κB and reduced expression of Bcl-2. We thus demonstrate for the first time that miR-146a/b regulates human DC apoptosis and cytokine production, uncovering a new negative feedback mechanism for miR-146 in controlling overstimulation of the immune responses (Fig. 2). Disclosures No relevant conflicts of interest to declare.

IMMU-13. COMBINED MODULATION OF THE TGF-Β PATHWAY AND GITR IMMUNE CHECKPOINT SIGNALING PROMOTES ANTI-TUMOR IMMUNITY IN SYNGENEIC GLIOMA MODELS

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi94-vi94
Author(s):  
Daniela Lorizio ◽  
Michael Weller ◽  
Manuela Silginer ◽  
Alan Epstein ◽  
Patrick Roth
Keyword(s):  
T Cell Activation ◽  
Immune Checkpoint ◽  
Cell Activation ◽  
Transforming Growth Factor ◽  
Immune Cell ◽  
Single Agent ◽  
Underlying Mechanism ◽  
T Effector Cells ◽  
Promising Therapeutic Approach

Abstract The profound local immunosuppressive microenvironment is one hallmark of glioblastoma, which results in resistance to most immunotherapeutic strategies that have been explored so far. Reverting this condition in order to reinvigorate anti-glioma immunity might be a promising therapeutic approach. Transforming growth factor (TGF)-β signaling is deregulated in different cancer types and contributes to the malignant phenotype of glioma cells. Glioma-derived TGF-β is also a major immunosuppressive factor in the tumor microenvironment. Furthermore, intratumoral regulatory T (Treg) cells and activated T effector cells express high levels of the co-stimulatory immune checkpoint glucocorticoid-induced tumor necrosis factor receptor (GITR). Agonistic anti-GITR antibodies have been explored in preclinical tumor models and are under investigation in clinical trials for the treatment of solid tumors. We evaluated the effect of TGF-β and GITR targeting on anti-tumor immune responses in syngeneic mouse glioma models. In co-culture settings, GITR modulation with a GITR ligand (GITRL)-Fc fusion protein, given alone or in combination with a pharmacological TGF-β receptor inhibitor, led to increased T cell activation. Furthermore, the combined targeting of the two pathways resulted in significantly higher immune cell-mediated tumor cell killing than either treatment alone. In vivo, TGF-β inhibition and GITR signaling modulation resulted in a higher fraction of long-term surviving glioma-bearing mice than single-agent treatment. Surviving mice were resistant to tumor re-challenge, suggesting adaptive immunity as an underlying mechanism. These data support the assumption that combined immunotherapeutic strategies may represent a promising approach for the treatment of glioma.

scholarly journals Coelonin, an Anti-Inflammation Active Component of Bletilla striata and Its Potential Mechanism

2019 ◽  
Vol 20 (18) ◽  
pp. 4422 ◽  
Author(s):  
Fusheng Jiang ◽  
Meiya Li ◽  
Hongye Wang ◽  
Bin Ding ◽  
Chunchun Zhang ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Kinase Inhibitor ◽  
Negative Regulator ◽  
Antibody Array ◽  
Dependent Manner ◽  
Active Ingredients ◽  
Bletilla Striata ◽  
Tnf Α ◽  
Anti Inflammatory

Ethanol extract of Bletilla striata has remarkable anti-inflammatory and anti-pulmonary fibrosis activities in the rat silicosis model. However, its active substances and molecular mechanism are still unclear. To uncover the active ingredients and potential molecular mechanism of the Bletilla striata extract, the lipopolysaccharide (LPS)-induced macrophage inflammation model and phospho antibody array were used. Coelonin, a dihydrophenanthrene compound was isolated and identified. It significantly inhibited LPS-induced interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) expression at 2.5 μg/mL. The microarray data indicate that the phosphorylation levels of 32 proteins in the coelonin pre-treated group were significantly down-regulated. In particular, the phosphorylation levels of the key inflammatory regulators factor nuclear factor-kappa B (NF-κB) were significantly reduced, and the negative regulator phosphatase and tensin homologue on chromosome ten (PTEN) was reduced. Moreover, the phosphorylation level of cyclin dependent kinase inhibitor 1B (p27Kip1), another downstream molecule regulated by PTEN was also reduced significantly. Western blot and confocal microscopy results confirmed that coelonin inhibited LPS-induced PTEN phosphorylation in a dose-dependent manner, then inhibited NF-κB activation and p27Kip1 degradation by regulating the phosphatidylinositol-3-kinases/ v-akt murine thymoma viral oncogene homolog (PI3K/AKT) pathway negatively. However, PTEN inhibitor co-treatment analysis indicated that the inhibition of IL-1β, IL-6 and TNF-α expression by coelonin was independent of PTEN, whereas the inhibition of p27Kip1 degradation resulted in cell-cycle arrest in the G1 phase, which was dependent on PTEN. The anti-inflammatory activity of coelonin in vivo, which is one of the main active ingredients of Bletilla striata, deserves further study.

scholarly journals Centrifugation Conditions in the L-PRP Preparation Affect Soluble Factors Release and Mesenchymal Stem Cell Proliferation in Fibrin Nanofibers

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2729 ◽  
Author(s):  
Melo ◽  
Luzo ◽  
Lana ◽  
Santana
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor ◽  
Platelet Rich Plasma ◽  
Clinical Practices ◽  
Soluble Factors ◽  
Tnf Α ◽  
Platelet Concentration ◽  
Tgf Β1

Leukocyte and platelet-rich plasma (L-PRP) is an autologous product that when activated forms fibrin nanofibers, which are useful in regenerative medicine. As an important part of the preparation of L-PRP, the centrifugation parameters may affect the release of soluble factors that modulate the behavior of the cells in the nanofibers. In this study, we evaluated the influences of four different centrifugation conditions on the concentration of platelets and leukocytes in L-PRP and on the anabolic/catabolic balance of the nanofiber microenvironment. Human adipose-derived mesenchymal stem cells (h-AdMSCs) were seeded in the nanofibers, and their viability and growth were evaluated. L-PRPs prepared at 100× g and 100 + 400× g released higher levels of transforming growth factor (TGF)-β1 and platelet-derived growth factor (PDGF)-BB due to the increased platelet concentration, while inflammatory cytokines interleukin (IL)-8 and tumor necrosis factor (TNF)-α were more significantly released from L-PRPs prepared via two centrifugation steps (100 + 400× g and 800 + 400× g) due to the increased concentration of leukocytes. Our results showed that with the exception of nanofibers formed from L-PRP prepared at 800 + 400× g, all other microenvironments were favorable for h-AdMSC proliferation. Here, we present a reproducible protocol for the standardization of L-PRP and fibrin nanofibers useful in clinical practices with known platelet/leukocyte ratios and in vitro evaluations that may predict in vivo results.

scholarly journals Receptor Heterodimerization and Co-Receptor Engagement in TLR2 Activation Induced by MIC1 and MIC4 from Toxoplasma gondii

2019 ◽  
Vol 20 (20) ◽  
pp. 5001 ◽  
Author(s):  
Flávia Costa Mendonça-Natividade ◽  
Carla Duque Lopes ◽  
Rafael Ricci-Azevedo ◽  
Aline Sardinha-Silva ◽  
Camila Figueiredo Pinzan ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Transforming Growth Factor Beta ◽  
Cell Activation ◽  
Cytokine Production ◽  
Transforming Growth Factor ◽  
Protein Complexes ◽  
Transmembrane Protein ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
Carbohydrate Recognition Domains

The microneme organelles of Toxoplasma gondii tachyzoites release protein complexes (MICs), including one composed of the transmembrane protein MIC6 plus MIC1 and MIC4. In this complex, carbohydrate recognition domains of MIC1 and MIC4 are exposed and interact with terminal sialic acid and galactose residues, respectively, of host cell glycans. Recently, we demonstrated that MIC1 and MIC4 binding to the N-glycans of Toll-like receptor (TLR) 2 and TLR4 on phagocytes triggers cell activation and pro-inflammatory cytokine production. Herein, we investigated the requirement for TLR2 heterodimerization and co-receptors in MIC-induced responses, as well as the signaling molecules involved. We used MICs to stimulate macrophages and HEK293T cells transfected with TLR2 and TLR1 or TLR6, both with or without the co-receptors CD14 and CD36. Then, the cell responses were analyzed, including nuclear factor-kappa B (NF-κB) activation and cytokine production, which showed that (1) only TLR2, among the studied factors, is crucial for MIC-induced cell activation; (2) TLR2 heterodimerization augments, but is not critical for, activation; (3) CD14 and CD36 enhance the response to MIC stimulus; and (4) MICs activate cells through a transforming growth factor beta-activated kinase 1 (TAK1)-, mammalian p38 mitogen-activated protein kinase (p38)-, and NF-κB-dependent pathway. Remarkably, among the studied factors, the interaction of MIC1 and MIC4 with TLR2 N-glycans is sufficient to induce cell activation, which promotes host protection against T. gondii infection.

scholarly journals Multiple myeloma increases nerve growth factor and other pain-related markers through interactions with the bone microenvironment

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sam W. Z. Olechnowicz ◽  
Megan M. Weivoda ◽  
Seint T. Lwin ◽  
Szi K. Leung ◽  
Sarah Gooding ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Cell Activation ◽  
Cellular Interactions ◽  
Bone Microenvironment ◽  
Related Factors ◽  
Nerve Growth ◽  
Tnf Α

Abstract Interactions between multiple myeloma (MM) and bone marrow (BM) are well documented to support tumour growth, yet the cellular mechanisms underlying pain in MM are poorly understood. We have used in vivo murine models of MM to show significant induction of nerve growth factor (NGF) by the tumour-bearing bone microenvironment, alongside other known pain-related characteristics such as spinal glial cell activation and reduced locomotion. NGF was not expressed by MM cells, yet bone stromal cells such as osteoblasts expressed and upregulated NGF when cultured with MM cells, or MM-related factors such as TNF-α. Adiponectin is a known MM-suppressive BM-derived factor, and we show that TNF-α-mediated NGF induction is suppressed by adiponectin-directed therapeutics such as AdipoRON and L-4F, as well as NF-κB signalling inhibitor BMS-345541. Our study reveals a further mechanism by which cellular interactions within the tumour-bone microenvironment contribute to disease, by promoting pain-related properties, and suggests a novel direction for analgesic development.

scholarly journals Acidosis-Induced TGF-β2 Production Promotes Lipid Droplet Formation in Dendritic Cells and Alters Their Potential to Support Anti-Mesothelioma T Cell Response

Cancers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1284
Author(s):  
Natalia Trempolec ◽  
Charline Degavre ◽  
Bastien Doix ◽  
Davide Brusa ◽  
Cyril Corbet ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Lipid Droplet ◽  
T Cell Activation ◽  
Cell Response ◽  
Cell Activation ◽  
Transforming Growth Factor ◽  
T Cell Response ◽  
Mesenchymal Transition

For poorly immunogenic tumors such as mesothelioma there is an imperious need to understand why antigen-presenting cells such as dendritic cells (DCs) are not prone to supporting the anticancer T cell response. The tumor microenvironment (TME) is thought to be a major contributor to this DC dysfunction. We have reported that the acidic TME component promotes lipid droplet (LD) formation together with epithelial-to-mesenchymal transition in cancer cells through autocrine transforming growth factor-β2 (TGF-β2) signaling. Since TGF-β is also a master regulator of immune tolerance, we have here examined whether acidosis can impede immunostimulatory DC activity. We have found that exposure of mesothelioma cells to acidosis promotes TGF-β2 secretion, which in turn leads to LD accumulation and profound metabolic rewiring in DCs. We have further documented how DCs exposed to the mesothelioma acidic milieu make the anticancer vaccine less efficient in vivo, with a reduced extent of both DC migratory potential and T cell activation. Interestingly, inhibition of TGF-β2 signaling and diacylglycerol O-acyltransferase (DGAT), the last enzyme involved in triglyceride synthesis, led to a significant restoration of DC activity and anticancer immune response. In conclusion, our study has identified that acidic mesothelioma milieu drives DC dysfunction and altered T cell response through pharmacologically reversible TGF-β2-dependent mechanisms.

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