Modulation of monocyte complement synthesis by interferons.
Ontology highlight
ABSTRACT:
SUBMITTER: Hamilton AO
PROVIDER: S-EPMC1147782 | biostudies-other | 1987 Mar
REPOSITORIES: biostudies-other
Similar Datasets
Project description:Interferons-alpha, -beta and -gamma (IFNs-alpha, -beta and -gamma) stimulated the synthesis of the second complement component (C2), Factor B (B) and C1 inhibitor (C1-inh) by human monocytes in vitro. The degree of increase of the secretion rates of C2, B and C1-inh was dose-dependent and proportional to increases in the abundances of their respective mRNAs. IFN-gamma was the most effective at stimulating monocyte C1-inh synthesis, whereas IFN-alpha and IFN-beta were marginally more effective at stimulating monocyte C2 and B synthesis. Kinetic studies showed that the effect of the IFNs was rapid, with maximum stimulation occurring within 1-2 h for all three proteins. After the removal of IFNs from cultures the C1-inh mRNA abundance remained elevated for over 24 h in IFN-gamma-treated monocytes but returned to control levels within 8 h in IFN-alpha-treated and IFN-beta-treated monocytes. The abundances of C2 mRNA and B mRNA also returned to basal values within 8 h after removal of any of the three cytokines from the cultures. Both IFN-alpha and IFN-beta acted synergistically with IFN-gamma to stimulate synthesis of C1-inh and B. This synergistic effect only occurred when the cytokines were present in the cultures simultaneously. The effects of IFN-gamma plus IFN-alpha or IFN-beta on C2 synthesis appeared to be additive rather than synergistic. IFN-gamma inhibited synthesis of C3 by monocytes, but IFN-alpha and IFN-beta had no effect on the synthesis of this protein. Furthermore, none of the three cytokines had any effect on the expression of actin mRNA in monocytes.
| S-EPMC1131444 | biostudies-other
Project description:Extracellular vesicles have an important function in cellular communication. Here, we show that human and mouse monocytes release TGF-β1-transporting vesicles in response to the pathogenic fungus Candida albicans. Soluble β-glucan from C. albicans binds to complement receptor 3 (CR3, also known as CD11b/CD18) on monocytes and induces the release of TGF-β1-transporting vesicles. CR3-dependence is demonstrated using CR3-deficient (CD11b knockout) monocytes generated by CRISPR-CAS9 genome editing and isolated from CR3-deficient (CD11b knockout) mice. These vesicles reduce the pro-inflammatory response in human M1-macrophages as well as in whole blood. Binding of the vesicle-transported TGF-β1 to the TGF-β receptor inhibits IL1B transcription via the SMAD7 pathway in whole blood and induces TGFB1 transcription in endothelial cells, which is resolved upon TGF-β1 inhibition. Notably, human complement-opsonized apoptotic bodies induce production of similar TGF-β1-transporting vesicles in monocytes, suggesting that the early immune response might be suppressed through this CR3-dependent anti-inflammatory vesicle pathway.
| S-EPMC7214408 | biostudies-literature
Project description:ObjectiveApoptotic cell receptors contribute to the induction of tolerance by modulating dendritic cell function following the uptake of apoptotic cells or microparticles. Dendritic cells that have bound or ingested apoptotic cells produce only low amounts of pro-inflammatory cytokines and fail to prime effector T cell responses. Specifically, ligation of the apoptotic cell receptor CR3 (CD11 b/CD18) on human monocyte-derived dendritic cells (moDC) down-modates proinflammatory cytokine secretion, but the consequences for human Th17 cell homeostasis and effector responses remain unknown. Here, we aimed to establish whether CD11b-ligated moDC modulate Th17 cell effector reponses to assess their potential for future use in moDC-based suppressive immunotherapy.MethodsWe generated a bead-based surrogate system to target CD11b on monocyte-derived human dendritic cells and examined the effects of CD11b ligation on Th17-skewing cytokine secretion, priming, expansion and functional plasticity in DC/T cell co-culture systems at the poly- and monoclonal level.ResultsWe show that Th17 cell expansion within the human memory CD4+ T cell compartment was efficiently constricted by targeting the CD11b receptor on moDC. This tolerogenic capacity was primarily dependent on cytokine skewing. Furthermore, ligation of CD11b on healthy homozygous carriers of the rs11143679 (ITGAM) variant - a strong genetic susceptibility marker for human systemic lupus erythematosus - also down-modulated the secretion of Th17-skewing cytokines.ConclusionOverall, our findings underline the potential of targeted CD11b ligation on human dendritic cells for the engineering of suppressive immunotherapy for Th17-related autoimmune disorders.
| S-EPMC6498856 | biostudies-literature
Project description:Extracellular vesicles play an important role in human cellular communication. Here, we show that human and mouse monocytes release TGF-β1-transporting vesicles in response to the pathogenic fungus Candida albicans. Soluble beta-glucan from Candida albicans binds to complement receptor 3 (CR3, CD11b/CD18) on monocytes and induces the release of TGF-β1-transporting vesicles. CR3-dependence is demonstrated using CR3-deficient (CD11b knockout) monocytes generated by CRISPR-CAS9 genome editing and isolated from CR3-deficient (CD11b knockout) mice. Isolated vesicles dampen the pro-inflammatory response in human M1-macrophages as well as in whole blood. Binding of the vesicle-transported TGF-β1 to the TGF-β receptor inhibits IL-1β gene transcription via the SMAD7 pathway in whole blood and induces TGF-β1 transcription in endothelial cells. Inhibition of TGF-β1 relieved the suppression of such proinflammatory effect. Notably, human opsonized apoptotic bodies induce similar TGF-β1-transporting vesicles in monocytes, suggesting that the early immune response is suppressed through this newly identified CR3-dependent anti-inflammatory vesicle pathway.
2020-04-22 | PXD015780 | Pride
Project description:Type I interferons (IFNs) play a key role in linking the innate and adaptive immune responses. IFNs can have both positive and negative effects on the development of memory CD8+ T cells, but their contribution to the priming of naïve T cells is unclear. Using OT-I TCR transgenic T cells, we show strong effects on TCR-induced functional response when sensitized by IFN-β prior to their stimulation with cognate antigen. These effects are only seen in the absence of co-stimulation and at suboptimal TCR stimulation conditions. Pre-stimulation of naïve T cells inhibits certain TCR-mediated functions like cell proliferation and the induction of genes such as IFN-γ and IL-2. However, type I IFN does not influence the induction of other TCR-induced functions like the expression of the T cell activation marker CD25 and a number of other genes. IFN-mediated impairment of proliferation is due to the lack of IL-2 induction since it can be compensated by exogenous IL-2. Further analysis reveals an IFN-mediated inhibition of Ca2+ flux and ERK phosphorylation. In vivo studies confirm that pre-stimulation with IFNs inhibits early T cell responses, whereas long-term responses are positively affected. Our results reveal that IFN exerts negative effects on naïve T cells in a timely defined range under sub-optimal TCR stimulation conditions. These results highlight the importance of timing of immune-regulatory events and reveal a novel role for type I IFNs by shaping the immune response, such that T cells are not able to react until optimal stimulation is provided. 8 Arrays, untreated cells as references, IFNb treatment and/or TCR stimulation at various lengths of time
2015-12-31 | E-GEOD-41381 | biostudies-arrayexpress
Project description:Type I interferons (IFNs) play a key role in linking the innate and adaptive immune responses. IFNs can have both positive and negative effects on the development of memory CD8+ T cells, but their contribution to the priming of naïve T cells is unclear. Using OT-I TCR transgenic T cells, we show strong effects on TCR-induced functional response when sensitized by IFN-β prior to their stimulation with cognate antigen. These effects are only seen in the absence of co-stimulation and at suboptimal TCR stimulation conditions. Pre-stimulation of naïve T cells inhibits certain TCR-mediated functions like cell proliferation and the induction of genes such as IFN-γ and IL-2. However, type I IFN does not influence the induction of other TCR-induced functions like the expression of the T cell activation marker CD25 and a number of other genes. IFN-mediated impairment of proliferation is due to the lack of IL-2 induction since it can be compensated by exogenous IL-2. Further analysis reveals an IFN-mediated inhibition of Ca2+ flux and ERK phosphorylation. In vivo studies confirm that pre-stimulation with IFNs inhibits early T cell responses, whereas long-term responses are positively affected. Our results reveal that IFN exerts negative effects on naïve T cells in a timely defined range under sub-optimal TCR stimulation conditions. These results highlight the importance of timing of immune-regulatory events and reveal a novel role for type I IFNs by shaping the immune response, such that T cells are not able to react until optimal stimulation is provided.
2015-12-31 | GSE41381 | GEO
Project description:Inflammatory monocyte-derived effector cells play an important role in the pathogenesis of numerous inflammatory diseases. However, no treatment option exists that is capable of modulating these cells specifically. We show that infused negatively charged, immune-modifying microparticles (IMPs), derived from polystyrene, microdiamonds, or biodegradable poly(lactic-co-glycolic) acid, were taken up by inflammatory monocytes, in an opsonin-independent fashion, via the macrophage receptor with collagenous structure (MARCO). Subsequently, these monocytes no longer trafficked to sites of inflammation; rather, IMP infusion caused their sequestration in the spleen through apoptotic cell clearance mechanisms and, ultimately, caspase-3-mediated apoptosis. Administration of IMPs in mouse models of myocardial infarction, experimental autoimmune encephalomyelitis, dextran sodium sulfate-induced colitis, thioglycollate-induced peritonitis, and lethal flavivirus encephalitis markedly reduced monocyte accumulation at inflammatory foci, reduced disease symptoms, and promoted tissue repair. Together, these data highlight the intricate interplay between scavenger receptors, the spleen, and inflammatory monocyte function and support the translation of IMPs for therapeutic use in diseases caused or potentiated by inflammatory monocytes.
| S-EPMC3973033 | biostudies-literature
Project description:Besides being a key effector arm of innate immunity, a plethora of non-canonical functions of complement has recently been emerging. Factor H (FH), the main regulator of the alternative pathway of complement activation, has been reported to bind to various immune cells and regulate their functions, beyond its role in modulating complement activation. In this study we investigated the effect of FH, its alternative splice product FH-like protein 1 (FHL-1), the FH-related (FHR) proteins FHR-1 and FHR-5, and the recently developed artificial complement inhibitor mini-FH, on two key innate immune cells, monocytes and neutrophilic granulocytes. We found that, similar to FH, the other factor H family proteins FHL-1, FHR-1 and FHR-5, as well as the recombinant mini-FH, are able to bind to both monocytes and neutrophils. As a functional outcome, immobilized FH and FHR-1 inhibited PMA-induced NET formation, but increased the adherence and IL-8 production of neutrophils. FHL-1 increased only the adherence of the cells, while FHR-5 was ineffective in altering these functions. The adherence of monocytes was increased on FH, recombinant mini-FH and FHL-1 covered surfaces and, except for FHL-1, the same molecules also enhanced secretion of the inflammatory cytokines IL-1β and TNFα. When monocytes were stimulated with LPS in the presence of immobilized FH family proteins, FH, FHL-1 and mini-FH enhanced whereas FHR-1 and FHR-5 decreased the secretion of TNFα; FHL-1 and mini-FH also enhanced IL-10 release compared to the effect of LPS alone. Our results reveal heterogeneous effects of FH and FH family members on monocytes and neutrophils, altering key features involved in pathogen killing, and also demonstrate that FH-based complement inhibitors, such as mini-FH, may have effects beyond their function of inhibiting complement activation. Thus, our data provide new insight into the non-canonical functions of FH, FHL-1, FHR-1 and FHR-5 that might be exploited during protection against infections and in vaccine development.
| S-EPMC8521052 | biostudies-literature
Project description:HIV-1 replication in macrophages can be regulated by cytokines and infection is restricted in macrophages activated by type I interferons and polarizing cytokines. Here, we observed that the expression levels of the cellular factors Trim5α, CypA, APOBEC3G, SAMHD-1, Trim22, tetherin and TREX-1, and the anti-HIV miRNAs miR-28, miR-150, miR-223 and miR-382 was upregulated by IFN-α and IFN-β in macrophages, which may account for the inhibiting effect on viral replication and the antiviral state of these cells. Expression of these factors was also increased by IFN-γ +/- TNF-α, albeit to a lesser extent; yet, HIV-1 replication in these cells was not restricted at the level of proviral synthesis, indicating that these cellular factors only partially contribute to the observed restriction. IL-4, IL-10 or IL-32 polarization did not affect the expression of cellular factors and miRNAs, suggesting only a limited role for these cellular factors in restricting HIV-1 replication in macrophages.
| S-EPMC3478582 | biostudies-literature
Project description:The effect of human immunodeficiency virus (HIV) infection and high-level HIV replication on the function of monocytes was investigated. HIV-positive patients had elevated levels of spontaneous production of some or all of the monocyte proinflammatory cytokines measured (interleukin-1beta [IL-1beta], IL-6, and tumor necrosis factor alpha [TNF-alpha]) compared to uninfected controls. In patients on therapy with high frequencies of monocytes producing proinflammatory cytokines, this frequency was diminished in the context of viremia during an interruption of therapy. Diminished production of proinflammatory cytokines during viremia was restored by culture with autologous CD4(+) T cells or monocytes from an on-therapy time point or lipopolysaccharide (LPS). Microarray analysis demonstrated that diminished monocyte production of proinflammatory cytokines was correlated with elevated type I interferon-stimulated gene transcripts. The addition of exogenous alpha 2A interferon diminished the spontaneous production of IL-1beta, IL-6, and TNF-alpha but did not affect responses to LPS, recapitulating the changes observed for HIV-viremic patients. These results suggest that monocyte function is diminished during high-level HIV viremia and that this effect is mediated by chronic stimulation by type I interferons. This effect on monocytes during viremia may play a role in diminished innate or adaptive immune system functions in HIV-infected patients. In addition, the restoration of these functions may also play a role in some immune reconstitution syndromes observed during initiation of therapy.
| S-EPMC1642603 | biostudies-literature