Anti-inflammatory Effects Of IL-10 Research Articles

Dramatic transcriptomic differences in Macaca mulatta and Macaca fascicularis with Plasmodium knowlesi infections

Plasmodium knowlesi, a model malaria parasite, is responsible for a significant portion of zoonotic malaria cases in Southeast Asia and must be controlled to avoid disease severity and fatalities. However, little is known about the host-parasite interactions and molecular mechanisms in play during the course of P. knowlesi malaria infections, which also may be relevant across Plasmodium species. Here we contrast P. knowlesi sporozoite-initiated infections in Macaca mulatta and Macaca fascicularis using whole blood RNA-sequencing and transcriptomic analysis. These macaque hosts are evolutionarily close, yet malaria-naïve M. mulatta will succumb to blood-stage infection without treatment, whereas malaria-naïve M. fascicularis controls parasitemia without treatment. This comparative analysis reveals transcriptomic differences as early as the liver phase of infection, in the form of signaling pathways that are activated in M. fascicularis, but not M. mulatta. Additionally, while most immune responses are initially similar during the acute stage of the blood infection, significant differences arise subsequently. The observed differences point to prolonged inflammation and anti-inflammatory effects of IL10 in M. mulatta, while M. fascicularis undergoes a transcriptional makeover towards cell proliferation, consistent with its recovery. Together, these findings suggest that timely detection of P. knowlesi in M. fascicularis, coupled with control of inflammation while initiating the replenishment of key cell populations, helps contain the infection. Overall, this study points to specific genes and pathways that could be investigated as a basis for new drug targets that support recovery from acute malaria.

Changes in Expression of the Membrane Receptors CD14, MHC-II, SR-A, and TLR4 in Tissue-Specific Monocytes/Macrophages Following Porphyromonas gingivalis-LPS Stimulation.

The aim of the study was to provide a theoretical foundation for understanding the relationship between periodontal diseases and systemic diseases by examining the inflammatory effect of Porphyromonas gingivalis lipopolysaccharide (LPS) on monocytes/macrophages isolated from tissues distinct from the oral cavity in normal and hyperlipidemic New Zealand white rabbits. Macrophages were isolated from four separate tissues (mononuclear cells from blood, alveolar macrophages, peritoneal macrophages, and Kupffer cells) from both normal and hyperlipidemic New Zealand white rabbits. Cells were either stimulated for 24h in vitro with P. gingivalis-LPS or Escherichia coli-LPS, or were pre-treated with IL-10 before P. gingivalis-LPS treatment. RNA was isolated and the expression of SR-A, TLR4, CD14, and MHC-II measured by RT-PCR. For MHC-II, the suppression effects of P. gingivalis-LPS were similar to the effects of E. coli-LPS in all macrophages examined. In general, the magnitude of the effects of P. gingivalis-LPS on gene expression was lower than that of E. coli-LPS, and there were differences in the relative membrane receptors between the two, implying that the two LPSs stimulate different responses. IL-10 increased the expression of the defensive receptor SR-A and decreased the expression of CD14, TLR4, and the antigen-presenting molecule MHC-II in all types of macrophages examined, regardless of hyperlipidemic state. These data are consistent with an anti-inflammatory effect of IL-10. P. gingivalis-LPS is an activator of gene expression in macrophages isolated from tissues distinct from the oral cavity.

IL-10 Can Enhance FcγR-mediated Mast Cell Activation

Abstract Mast cells are involved in many inflammatory diseases, partly by their production of cytokines that promote inflammation. IgG signaling through FcγRIII/IIb in mast cells is linked to autoimmune disease such as rheumatoid arthritis, but factors controlling this signaling remain unclear. Our group, as well as others, has previously shown that IL-10 suppresses mast cell IgE signaling, consistent with known anti-inflammatory effects of IL-10. However, we recently found that in IL-10 has unexpected pro-inflammatory effects on IgE-mediated mast cell functions. Therefore, we designed a study to determine the effects of IL-10 on FcγR signaling. Our data show that IL-10 enhances IgG-mediated IL-6 and MCP-1 production in bone marrow derived mast cells. Interestingly, we also found that IgG-induced cytokine production is suppressed by IL-10 in bone marrow derived macrophages under the same conditions. Current work is examining this different response to IL-10 to have a better understanding of the overall affect of IL-10 in the inflamed microenvironment. These studies suggest that mast cell and macrophage responses are altered by cytokines in their microenvironment, with distinct and opposite effects.

Tristetraprolin Is Required for Full Anti-Inflammatory Response of Murine Macrophages to IL-10

IL-10 is essential for inhibiting chronic and acute inflammation by decreasing the amounts of proinflammatory cytokines made by activated macrophages. IL-10 controls proinflammatory cytokine and chemokine production indirectly via the transcription factor Stat3. One of the most physiologically significant IL-10 targets is TNF-alpha, a potent proinflammatory mediator that is the target for multiple anti-TNF-alpha clinical strategies in Crohn's disease and rheumatoid arthritis. The anti-inflammatory effects of IL-10 seem to be mediated by several incompletely understood transcriptional and posttranscriptional mechanisms. In this study, we show that in LPS-activated bone marrow-derived murine macrophages, IL-10 reduces the mRNA and protein levels of TNF-alpha and IL-1alpha in part through the RNA destabilizing factor tristetraprolin (TTP). TTP is known for its central role in destabilizing mRNA molecules containing class II AU-rich elements in 3' untranslated regions. We found that IL-10 initiates a Stat3-dependent increase of TTP expression accompanied by a delayed decrease of p38 MAPK activity. The reduction of p38 MAPK activity releases TTP from the p38 MAPK-mediated inhibition, thereby resulting in diminished mRNA and protein levels of proinflammatory cytokines. These findings establish that TTP is required for full responses of bone marrow-derived murine macrophages to IL-10.

Leukocyte-Derived IL-10 Reduces Subepithelial Fibrosis Associated with Chronically Inhaled Endotoxin

Endotoxin (LPS), a Gram-negative cell wall component, has potent proinflammatory properties. Acute LPS exposure causes airway inflammation; chronic exposure causes airway hyperreactivity and remodeling. IL-10 is an important antiinflammatory cytokine, which is decreased in patients with airway disease, such as asthma and cystic fibrosis. To examine the physiologic and therapeutic role of IL-10 in acute and chronic LPS-induced airway disease. Mice were exposed to aerosolized LPS once or daily for 4 wk. Endpoints were airway inflammation, airway reactivity to methacholine, extracellular matrix protein expression, and histologic analysis. IL-10-deficient mice developed significantly enhanced airway cellularity and remodeling when compared with C57BL/6 mice after chronic LPS inhalation. However they demonstrated less airway hyperreactivity associated with higher inducible nitric oxide synthase (iNOS), endothelial NOS (eNOS), and lung lavage fluid nitrite levels. In a bone marrow transplantation model, the IL-10 antiinflammatory effect was dependent on the hematopoietic but not on the parenchymal IL-10 expression. Induced epithelial human IL-10 expression protected from the LPS effects and led to decreased collagen production. IL-10 attenuates chronic LPS-induced airway inflammation and remodeling. Physiologically, the antiinflammatory effect of IL-10 is mediated by hematopoietic cells. Therapeutically, adenovirus-driven expression of human IL-10 in airway epithelia is sufficient for its protective effect on inflammation and remodeling. The role of IL-10 on airway hyperreactivity is complex: IL-10 deficiency protects against LPS-induced hyperreactivity, and is associated with higher eNOS, iNOS, and airway nitrate levels.

Inhibition of IL-10-induced STAT3 activation by 15-deoxy-Δ12,14-prostaglandin J2

15-Deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2) is a natural ligand that activates the peroxisome proliferator-activated receptor (PPAR)-gamma, a member of the nuclear receptor family implicated in the regulation of lipid metabolism and adipocyte differentiation. Recent data have shown that 15d-PGJ2 exerts anti-inflammatory action via inhibition of the interferon gamma (IFN-gamma)-induced Jak-STAT signalling pathway. The anti-inflammatory effect of IL-10 is mediated via activated STAT3 (signal transducer and activator of transcription 3). In this study, we investigated whether 15d-PGJ2 inhibit IL-10-induced STAT activation. We used western blotting, flow cytometric analysis and a real-time polymerase chain reaction. 15d-PGJ2 blocked IL-10-induced STAT1 and STAT3 activation in primary human monocytes, macrophages and THP-1 cells. Inhibition was not specific for IL-10, as induction of STAT activation by IFN-gamma and IL-6 was also inhibited by 15d-PGJ2. Inhibition of IL-10 signalling was induced within 1 h after pretreatment of 15d-PGJ2. Other PPARgamma agonists, such as troglitazone, did not inhibit IL-10 signalling. Treatment with GW9662, a specific PPARgamma antagonist, had no effect on 15d-PGJ2-mediated inhibition of IL-10 signalling even at higher concentrations (50 microM), indicating that 15d-PGJ2 affects the IL-10-induced Jak-STAT signalling pathway via an PPARgamma-independent mechanism. Actinomycin D had no effect on 15d-PGJ2-mediated inhibition of IL-10 signalling, indicating that inhibition of IL-10 signalling occurs independently of de novo gene expression. Also, inhibitors of extracellular signal-regulated kinase (ERKs) (PD98059), p38 MAPK (mitogen-activated protein kinase) (SB203580) and protein kinase C (PKC) (GF109203X, calphostin C) had no effect on 15d-PGJ2-mediated inhibition of IL-10 signalling. These results show that MAPKs and PKC are not involved in the inhibition of IL-10 signalling. We showed that 15d-PGJ2 non-specifically inhibits STAT signalling of the anti-inflammatory cytokine IL-10 as well as the proinflammatory cytokine IFN-gamma. These findings indicate the possibility that 15d-PGJ2 can have adverse effects in the management of diseases in which IL-10 plays a critical role in the suppression of inflammation.

Antithetical effects of hemicellulase‐treated Agaricus blazei on the maturation of murine bone‐marrow‐derived dendritic cells

We report the effects of hemicellulase-treated Agaricus blazei (ABH) on the maturation of bone-marrow-derived dendritic cells (BMDCs). ABH activated immature BMDCs, inducing up-regulation of surface molecules, such as CD40, CD80 and major histocompatibility complex class I antigens, as well as inducing allogeneic T-cell proliferation and T helper type 1 cell development. However, unlike lipopolysaccharide (LPS), ABH did not stimulate the BMDCs to produce proinflammatory cytokines, such as interleukin-12 (IL-12) p40, tumour necrosis factor-alpha, or IL-1beta. In addition, ABH suppressed LPS-induced DC responses. Pretreatment of DCs with ABH markedly reduced the levels of LPS-induced cytokine secretion, while only slightly decreasing up-regulation of the surface molecules involved in maturation. ABH also had a significant impact on peptidoglycan-induced or CpG oligodeoxynucleotide-induced IL-12p40 production in DCs. The inhibition of LPS-induced responses was not associated with a cytotoxic effect of ABH nor with an anti-inflammatory effect of IL-10. However, ABH decreased NF-kappaB-induced reporter gene expression in LPS-stimulated J774.1 cells. Interestingly, DCs preincubated with ABH and then stimulated with LPS augmented T helper type 1 responses in culture with allogeneic T cells as compared to LPS-stimulated but non-ABH-pretreated DCs. These observations suggest that ABH regulates DC-mediated responses.

Adherence influences monocyte responsiveness to interleukin-10.

We studied the effects of adherence on the properties of interleukin (IL)-10 on monocyte-enriched peripheral blood mononuclear cells. We found that the decrease of CD11b expression induced by IL-10 was enhanced by adherence. Toll-like receptor (TLR)2 and TLR4 mRNA, as well as TLR4 surface expression, were significantly up-regulated by IL-10 in adherent cells. The absence of adherence prevented the inhibitory effects of IL-10 on lipopolysaccharide-induced tumor necrosis factor (TNF) and granulocyte-colony stimulating factor production and increased IL-1beta production and soluble TNF receptor II release in IL-10-pretreated cells. Similarly, the absence of adherence amplified the enhancement of phagocytosis induced by IL-10. Tyk2 and signal transducer and activator of transcription 3 (STAT3) phosphorylation and suppressor of cytokine signaling 3 (SOCS3) expression were induced by IL-10 in both conditions, but a longer activation and/or expression were observed in adherent monocytes. Finally, heme oxygenase-1, an anti-inflammatory molecule, was induced by IL-10 in adherent monocytes, whereas its expression remained low in nonadherent cells. Altogether, these data illustrate that adherence modulates the properties and the anti-inflammatory effects of IL-10.

INTERLEUKIN 10 MODULATION OF TUMOUR NECROSIS FACTOR RECEPTORS REQUIRES TYROSINE KINASES BUT NOT THE PI 3-KINASE/p70 S6 KINASE PATHWAY

We have previously shown that interleukin (IL-)10-induced proliferation of the murine mast cell line D36, was dependent upon the activation of PI 3-kinase and p70 S6 kinase. Conversely, we were able to show that this pathway was not involved in the signal transduction pathway mediating IL-10 inhibition of pro-inflammatory cytokine release from monocytes. We have extended these studies to investigate the induction of p75 tumour necrosis factor receptor (TNF-R) shedding, another anti-inflammatory property of IL-10. Using the inhibitors of PI 3-kinase (LY294002 and wortmannin) and an inhibitor of p70 S6 kinase activation (rapamycin), we were able to show that this anti-inflammatory effect of IL-10 was not mediated by the PI 3-kinase/p70 S6 kinase pathway, indicating that another signalling cascade(s) was involved. Further studies also investigated the role of tyrosine kinases in the response to IL-10. Two distinct tyrosine kinase inhibitors, herbimycin and genistein affected the expression of TNF-R in response to IL-10 but, surprisingly, with opposite effects. However, both compounds inhibited the activation of both PI 3-kinase and p70 S6 kinase, with a concomitant inhibition of IL-10-induced proliferation. We observed that whilst tyrosine kinase activity was involved in the regulation of TNF-R expression, IL-10-induced activation of JAK kinases was not sensitive to inhibition by the tyrosine kinase inhibitors. These data suggest that multiple unknown tyrosine kinases are mediating the IL-10-induced signal transduction pathways leading to the regulation of TNF-R expression and IL-10-induced proliferation.