Geobarrettin D, a Rare Herbipoline-Containing 6-Bromoindole Alkaloid from Geodia barretti.

Geobarrettin D (1), a new bromoindole alkaloid, was isolated from the marine sponge Geodia barretti collected from Icelandic waters. Its structure was elucidated by 1D, and 2D NMR (including 1H-15N HSQC, 1H-15N HMBC spectra), as well as HRESIMS data. Geobarrettin D (1) is a new 6-bromoindole featuring an unusual purinium herbipoline moiety. Geobarrettin D (1) decreased secretion of the pro-inflammatory cytokine IL-12p40 by human monocyte derived dendritic cells, without affecting secretion of the anti-inflammatory cytokine IL-10. Thus, compound 1 shows anti-inflammatory activity.

Anti-Inflammatory and Proresolving Effects of the Omega-6 Polyunsaturated Fatty Acid Adrenic Acid.

Polyunsaturated fatty acids (PUFAs) and their metabolites are potent regulators of inflammation. Generally, omega (n)-3 PUFAs are considered proresolving whereas n-6 PUFAs are classified as proinflammatory. In this study, we characterized the inflammatory response in murine peritonitis and unexpectedly found the accumulation of adrenic acid (AdA), a poorly studied n-6 PUFA. Functional studies revealed that AdA potently inhibited the formation of the chemoattractant leukotriene B4 (LTB4), specifically in human neutrophils, and this correlated with a reduction of its precursor arachidonic acid (AA) in free form. AdA exposure in human monocyte-derived macrophages enhanced efferocytosis of apoptotic human neutrophils. In vivo, AdA treatment significantly alleviated arthritis in an LTB4-dependent murine arthritis model. Our findings are, to our knowledge, the first to indicate that the n-6 fatty acid AdA effectively blocks production of LTB4 by neutrophils and could play a role in resolution of inflammation in vivo.

Keratinocytes secrete multiple inflammatory and immune biomarkers, which are regulated by LL-37, in a psoriasis mimicking microenvironment.

Psoriasis is an autoimmune disease driven by a Th17 response linked to the antimicrobial peptide (AMP) LL-37 that has been connected to the induction and chronicity of psoriasis. We show that keratinocytes secrete various immune biomarkers with a direct link to psoriasis immunopathogenesis. Under pro-inflammatory microenvironmental conditions, LL-37 was found to regulate keratinocyte secretion of various immune biomarkers (eg C-X-C motif chemokine ligand (CXCL)8 and interleukin (IL)-1ß) and alter extracellular signal-regulated kinase (ERK)1/2 signalling. However, during neutral conditions LL-37 induced a different pattern of keratinocyte immune biomarker secretion (eg vascular endothelial growth factor, CXCL8 and IL-6). Thus, an interesting pattern emerged regarding the immunomodulatory effects of LL-37 on keratinocytes; in general, expression of immune biomarkers that were upregulated in a Th1-like microenvironment was downregulated in the presence of LL-37. In contrast, LL-37 reinforced the Th17 response. In active psoriatic skin lesions, LL-37 expression was found to be significantly upregulated, which was also evident from the unique diffuse epidermic expression pattern not found in healthy skin. Finally, successful phototherapy of psoriasis patients converted this LL-37 inflammatory psoriatic skin pattern into a more localized basal layer expression as found in healthy controls. Thus, these findings demonstrate that LL-37 has a significant role in skin immune homeostasis and that its interplay with keratinocytes may have a more direct role in the immunopathogenesis of psoriasis than previously thought.

Bromotryptamine and Imidazole Alkaloids with Anti-inflammatory Activity from the Bryozoan Flustra foliacea.

Chemical investigation of the marine bryozoan Flustra foliacea collected in Iceland resulted in isolation of 13 new bromotryptamine alkaloids, flustramines Q-W (1-7) and flustraminols C-H (8-13), and two new imidazole alkaloids, flustrimidazoles A and B (14 and 15), together with 12 previously described compounds (16-27). Their structures were established by detailed spectroscopic analysis using 1D and 2D NMR and HRESIMS. Structure 2 was verified by calculations of the 13C and 1H NMR chemical shifts using density functional theory. The relative and absolute configurations of the new compounds were elucidated on the basis of coupling constant analysis, NOESY, [α]D, and ECD spectroscopic data, in addition to chemical derivatization. The compounds were tested for in vitro anti-inflammatory activity using a dendritic cell model. Eight compounds (1, 3, 5, 13, 16, 18, 26, and 27) decreased dendritic cell secretion of the pro-inflammatory cytokine IL-12p40, and two compounds (4 and 14) increased secretion of the anti-inflammatory cytokine IL-10. Deformylflustrabromine B (27) showed the most potent anti-inflammatory effect (IC50 2.9 µM). These results demonstrate that F. foliacea from Iceland expresses a broad range of brominated alkaloids, many without structural precedents. The potent anti-inflammatory activity in vitro of metabolite 27 warrants further investigations into its potential as a lead for inflammation-related diseases.

6-Bromoindole Derivatives from the Icelandic Marine Sponge Geodia barretti: Isolation and Anti-Inflammatory Activity.

An UPLC-qTOF-MS-based dereplication study led to the targeted isolation of seven bromoindole alkaloids from the sub-Arctic sponge Geodia barretti. This includes three new metabolites, namely geobarrettin A⁻C (1⁻3) and four known compounds, barettin (4), 8,9-dihydrobarettin (5), 6-bromoconicamin (6), and l-6-bromohypaphorine (7). The chemical structures of compounds 1⁻7 were elucidated by extensive analysis of the NMR and HRESIMS data. The absolute stereochemistry of geobarrettin A (1) was assigned by ECD analysis and Marfey's method employing the new reagent l-Nα-(1-fluoro-2,4-dinitrophenyl)tryptophanamide (l-FDTA). The isolated compounds were screened for anti-inflammatory activity using human dendritic cells (DCs). Both 2 and 3 reduced DC secretion of IL-12p40, but 3 concomitantly increased IL-10 production. Maturing DCs treated with 2 or 3 before co-culturing with allogeneic CD4⁺ T cells decreased T cell secretion of IFN-γ, indicating a reduction in Th1 differentiation. Although barettin (4) reduced DC secretion of IL-12p40 and IL-10 (IC50 values 11.8 and 21.0 µM for IL-10 and IL-12p40, respectively), maturing DCs in the presence of 4 did not affect the ability of T cells to secrete IFN-γ or IL-17, but reduced their secretion of IL-10. These results indicate that 2 and 3 may be useful for the treatment of inflammation, mainly of the Th1 type.

Lipophilic fractions from the marine sponge Halichondria sitiens decrease secretion of pro-inflammatory cytokines by dendritic cells and decrease their ability to induce a Th1 type response by allogeneic CD4+ T cells.

CONTEXT: Halichondria (Halichondriidae) marine sponges contain components possessing various biological activities, but immunomodulation is not among the ones reported. OBJECTIVE: This study evaluated the immunomodulatory effects of fractions/compounds from Halichondria sitiens Schmidt. MATERIALS AND METHODS: Crude dichloromethane/methanol extracts of H. sitiens were subjected to various chromatographic techniques to obtain fractions/compounds with immunomodulatory activity, using bioassay-guided isolation. The effects of the fractions/compounds were determined by measuring secretion of cytokines and expression of surface molecules by dendritic cells (DCs) and their ability to stimulate and modify cytokine secretion by allogeneic CD4+ T cells. The bioactive fractions were chemically analyzed to identify the immunomodulatory constituents by 1D, 2D NMR, and HRMS data. RESULTS: Several lipophilic fractions from H. sitiens at 10 µg/mL decreased secretion of the pro-inflammatory cytokines IL-12p40 and IL-6 by the DCs, with maximum inhibition being 64% and 25%, respectively. In addition, fractions B3b3F and B3b3J decreased the ability of DCs to induce T cell secretion of IFN-γ. Fraction B3b3 induced morphological changes in DCs, characterized by extreme elongation of dendrites and cell clustering. Chemical screening revealed the presence of glycerides and some minor unknown constituents in the biologically active fractions. One new glyceride, 2,3-dihydroxypropyl 2-methylhexadecanoate (1), was isolated from one fraction and two known compounds, 3-[(1-methoxyhexadecyl)oxy]propane-1,2-diol (2) and monoheptadecanoin (3), were identified in another, but none of them had immunomodulatory activity. DISCUSSION AND CONCLUSIONS: These results demonstrate that several lipophilic fractions from H. sitiens have anti-inflammatory effects on DCs and decrease their ability to induce a Th1 type immune response.

Acute phase inflammation is characterized by rapid changes in plasma/peritoneal fluid N-glycosylation in mice.

Murine zymosan-induced peritonitis is a widely used model for studying the molecular and cellular events responsible for the initiation, persistence and/or resolution of inflammation. Among these events, it is becoming increasingly evident that changes in glycosylation of proteins, especially in the plasma and at the site of inflammation, play an important role in the inflammatory response. Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS)-based glycosylation profiling, we investigated the qualitative and quantitative effect of zymosan-induced peritonitis on N-glycosylation in mouse plasma and peritoneal fluid. Our results show that both N-glycomes exhibit highly similar glycosylation patterns, consisting mainly of diantennary and triantennary complex type N-glycans with high levels (>95 %) of galactosylation and sialylation (mostly NeuGc) and a medium degree of core fucosylation (30 %). Moreover, MS/MS structural analysis, assisted by linkage-specific derivatization of sialic acids, revealed the presence of O-acetylated sialic acids as well as disialylated antennae ("branching sialylation") characterized by the presence of α2-6-linked NeuGc on the GlcNAc of the NeuGcα2-3-Galß1-3-GlcNAc terminal motif. A significant decrease of (core) fucosylation together with an increase of both α2-3-linked NeuGc and "branching sialylation" were observed in N-glycomes of mice challenged with zymosan, but not in control mice injected with PBS. Importantly, substantial changes in glycosylation were already observed 12 h after induction of peritonitis, thereby demonstrating an unexpected velocity of the biological mechanisms involved.

Immunomodulatory N-acyl Dopamine Glycosides from the Icelandic Marine Sponge Myxilla incrustans Collected at a Hydrothermal Vent Site.

A chemical investigation of the sponge (Porifera) Myxilla incrustans collected from the unique submarine hydrothermal vent site Strytan, North of Iceland, revealed a novel family of closely related N-acyl dopamine glycosides. Three new compounds, myxillin A (1), B (2) and C (3), were isolated and structurally elucidated using several analytical techniques, such as HR-MS, 1D and 2D NMR spectroscopy. Myxillin A (1) and B (2)were shown to be structurally similar, composed of a dopamine moiety, but differ in the acyl chain length and saturation. The myxillin C (3) has a dehydrotyrosine moiety composing the same acyl chain and glycosylation as myxillin B (2). Myxillins A (1) and C (3) were tested for immunomodulating activity in an in vitro dendritic cell model. Dendritic cells matured and stimulated in the presence of myxillin A (1) secreted lower levels of IL-12p40, whilst dendritic cells matured and stimulated in the presence of myxillin C (3) secreted lower levels of IL-10 compared with dendritic cells matured and stimulated in the presence of the solvent alone. These opposing results indicate that the structural differences in the aromatic ring part of the molecules could have an impact on the immunological effects of dendritic cells. These molecules could, therefore, prove to be important in preventing inflammatory diseases on the one hand, and inducing a response to fight tumors and/or pathogens on the other hand. Further studies will be needed to confirm these potential uses.

Differential mobility separation of leukotrienes and protectins.

Differential mobility spectrometry (DMS) is capable of separating stereoisomeric molecular ions based on their mobility in an oscillating electrical field with an asymmetric waveform. Thus, it is an "orthogonal" technique to chromatography and (tandem) mass spectrometry. Bioactive lipids, particularly of the eicosanoid and docosanoid class feature numerous stereoisomers, which exhibit a highly specific structure-activity relationship. Moreover, the geometry of these compounds also reflects their biochemical origin. Therefore, the unambiguous characterization of related isomers of the eicosanoid and docosanoid classes is of fundamental importance to the understanding of their origin and function in many biological processes. Here we show, that SelexION DMS technology coupled to µLC-MS/MS is capable of differentiating at least five closely related leukotrienes partially coeluting and (almost) unresolvable using LC-MS/MS only. We applied the developed method to the separation of LTB4 and its coeluting isomer 5S,12S-diHETE in murine peritoneal exudate cells, showing that LTB4 is present only after zymosan A injection while its isomer 5S,12S-diHETE is produced after saline (PBS) administration. Additionally, we show that the SelexION technology can also be applied to the separation of PD1 and PDX (10S,17S-diHDHA), two isomeric protectins.

Effect of in vitro digested cod liver oil of different quality on oxidative, proteomic and inflammatory responses in the yeast Saccharomyces cerevisiae and human monocyte-derived dendritic cells.

BACKGROUND: Upon oxidation of the polyunsaturated fatty acids in fish oil, either before ingestion or, as recently shown, during the gastro-intestinal passage, a cascade of potentially cytotoxic peroxidation products, such as malondialdehyde and 4-hydroxy-2-hexenal, can form. In this study, we digested fresh and oxidised cod liver oils in vitro, monitored the levels of lipid peroxidation products and evaluated oxidative, proteomic and inflammatory responses to the two types of digests in the yeast Saccharomyces cerevisiae and human monocyte-derived dendritic cells. RESULTS: Digests of cod liver oil with 22-53 µmol L(-1) malondialdehyde and 0.26-3.7 µmol L(-1) 4-hydroxy-2-hexenal increased intracellular oxidation and cell energy metabolic activity compared to a digested blank in yeast cells and the influence of digests on mitochondrial protein expression was more pronounced for oxidised cod liver oil than fresh cod liver oil. The four differentially expressed and identified proteins were related to energy metabolism and oxidative stress response. Maturation of dendritic cells was affected in the presence of digested fresh cod liver oil compared to the digested blank, measured as lower CD86 expression. The ratio of secreted cytokines, IL-12p40/IL-10, suggested a pro-inflammatory effect of the digested oils in relation to the blank (1.47-1.67 vs. 1.07). CONCLUSION: Gastro-intestinal digestion of cod liver oil increases the amount of oxidation products and resulting digests affect oxidation in yeast and immunomodulation of dendritic cells.

Dietary fish oil decreases the proportion of classical monocytes in blood in healthy mice but increases their proportion upon induction of inflammation.

Fish oil can have beneficial effects in health and disease. In healthy individuals, reduction of the inflammatory status may be of benefit, whereas in patients with systemic inflammation, such as sepsis, it is important to diminish the immunosuppression that is thought to contribute to poor outcome. The objective of this study was to determine the effects of dietary fish oil on monocytes/macrophages in blood, bone marrow, spleen, and peritoneum and chemokine concentrations in blood and peritoneum in healthy mice and mice with endotoxin-induced inflammation. Mice were fed a Western-type diet without fish oil (C) or with 2.8% fish oil (FO) for 6 wk and then either killed (healthy mice) or injected i.p. with endotoxin (LPS) and killed after 3, 8, 12, 24, or 48 h. Blood, bone marrow, spleen, and peritoneal lavage were collected. Expression of cell surface molecules and chemokine receptors was analyzed by flow cytometry and chemokine concentrations measured by ELISA. Healthy mice in the FO group had lower proportions of classical monocytes in blood than healthy mice in the C group. LPS administration increased the proportion of classical monocytes in blood in mice in the FO group but not in those in the C group. Healthy mice in the FO group had lower serum concentrations of CCL2 than mice in the C group, but in inflamed mice, CCL2 concentrations were higher in the FO group than in the C group. These results indicate that dietary fish oil can attenuate the inflammatory status in homeostasis but intensify the immune response upon inflammation.

Two circulating neutrophil populations in acute inflammation in mice.

OBJECTIVE AND DESIGN: Recent studies indicate that neutrophils are heterogeneous and may have an immunosuppressive role in addition to their well-known phagocytic and bactericidal function. This study examined neutrophil subpopulations in the circulation, peritoneum, spleen and bone marrow from mice at various time points after induction of acute inflammation. MATERIAL, TREATMENT AND METHODS: Female C57BL/6 mice were injected intraperitoneally with lipopolysaccharide (LPS). Blood, peritoneal, spleen and bone marrow cells were collected and counted and expression of surface molecules and chemokine receptors analyzed with flow cytometry. Chemokine and cytokine concentrations in serum and peritoneal fluid were determined by ELISA. RESULTS: Neutrophil numbers in the circulation decreased following administration of LPS but reached similar numbers to those prior to inflammation at 8 h. At that time point, two distinct neutrophil populations were present in the circulation. These two neutrophil populations differed in size, granularity and expression of CD11b and Ly6G. Few neutrophils were recruited into the peritoneum until 24 h after administration of LPS at a time when the neutrophils in the circulation had increased their expression of the chemokine receptor CXCR2. CONCLUSIONS: Induction of acute inflammation leads to the appearance of two circulating neutrophil subpopulations, which may differ in their activation state and function.

Dietary Fish Oil Increases the Number of CD11b+CD27- NK Cells at the Inflammatory Site and Enhances Key Hallmarks of Resolution of Murine Antigen-Induced Peritonitis.

PURPOSE: To determine the effects of dietary omega-3 polyunsaturated fatty acids (PUFAs) on recruitment of natural killer (NK) cells and resolution responses in antigen-induced peritonitis in mice. METHODS: Mice were fed fish oil-enriched or control diets, immunized twice and challenged intraperitoneally with methylated bovine serum albumin. Prior to and at different time-points following inflammation induction, expression of surface molecules on peritoneal cells was determined by flow cytometry, concentration of soluble mediators in peritoneal fluid by ELISA or Luminex, and of lipid mediators by LC-MS/MS, and number of apoptotic cells in mesenteric lymph nodes by TUNEL staining. RESULTS: Mice fed the fish oil diet had higher number of CD11b+CD27- NK cells as well as a higher proportion of CD107a+ NK cells in their peritoneum 6 h after inflammation induction than mice fed the control diet. They also had higher numbers of CCR5+ NK cells and higher concentrations of CCL5 and CXCL12. Additionally, a higher fraction of apoptotic neutrophils but lower fraction of CD47+ neutrophils were present in the peritoneum of mice fed the fish oil diet 6 h after inflammation induction and the fish oil fed mice had a shorter resolution interval. They also had lower concentrations of pro-inflammatory mediators but higher concentrations of the anti-inflammatory/pro-resolution mediators TGF-ß, IGF-1, and soluble TNF RII, as well as higher ratios of hydroxyeicosapentaenoic acid (HEPE) to hydroxyeicosatetraenoic acid (HETE) than mice fed the control diet. CONCLUSION: The results demonstrate that dietary fish oil increases the number of mature NK cells at the inflamed site in antigen-induced peritonitis and enhances several key hallmarks of resolution of inflammation, casting light on the potential mechanisms involved.

Emu Oil and Saireito in combination reduce tumour development and clinical indicators of disease in a mouse model of colitis-associated colorectal cancer.

BACKGROUND: Emu Oil (EO) previously demonstrated therapeutic potential in a mouse model of colitis-associated CRC (CA-CRC). Saireito, a traditional Japanese medicine, has not been investigated in CA-CRC. AIM: To determine whether EO and Saireito could be therapeutic in an azoxymethane (AOM)/dextran sulphate sodium (DSS) model of CA-CRC. METHODS: Female C57BL/6 mice were assigned to groups (n = 10/group); 1) saline control, 2) saline+Saireito, 3) saline+EO, 4) saline+EO/Saireito, 5) AOM/DSS control, 6) AOM/DSS+Saireito, 7) AOM/DSS+EO and 8) AOM/DSS+EO/Saireito. Mice were intraperitoneally injected with saline or AOM (7.4 mg/kg) on day 0 and underwent three DSS/water cycles (2%w/v DSS for 7 days, 14 days water). Mice were orally-gavaged with either water (80 µL), Saireito (80 µL), EO (80 µL) or EO/Saireito (160 µL; 80 µL EO + 80 µL Saireito) thrice weekly. Daily bodyweight and disease activity index (DAI) were recorded and colonoscopies performed on days 20, 41 and 62. Mice were euthanized on day 63. p < 0.05 was considered statistically significant. RESULTS: AOM/DSS induced significant bodyweight loss throughout the trial (max -36%), which was attenuated by Saireito (max +7%), EO (max +5%) and EO/Saireito (max +14%; p < 0.05). AOM/DSS increased DAI compared to saline controls (p < 0.05), which was reduced by Saireito, EO and EO/Saireito (p < 0.05). All treatments reduced colonoscopically-assessed colitis severity (days 20 and 41; p < 0.05). EO/Saireito further decreased colitis severity compared to Saireito and EO alone (day 20; p < 0.05). Finally, EO and EO/Saireito resulted in fewer colonic tumours compared to AOM/DSS controls (p < 0.05). CONCLUSION: Combined EO and Saireito reduced disease and tumour development in AOM/DSS mice, suggesting therapeutic potential in CA-CRC.

Docosahexaenoic Acid Modulates NK Cell Effects on Neutrophils and Their Crosstalk.

Natural killer (NK) cells and neutrophils engage in crosstalk that is important in inflammation and likely also for resolution of inflammation. NK cells activate neutrophils and induce their infiltration to the inflamed sites but may also influence their apoptosis and their subsequent efferocytosis by macrophages. Several studies indicate that docosahexaenoic acid (DHA) can inhibit NK cell cytotoxicity but the effects of DHA on the ability of NK cells to engage in crosstalk with neutrophils and affect their functions have not been described. This study explored the kinetics of the effects of NK cells and NK cells pre-treated with DHA on neutrophil surface molecule expression and apoptosis, as well as the ability of NK cells to affect other neutrophil functions. In addition, the study explored the effects of neutrophils on NK cell phenotype and function. Primary NK cells were pre-incubated with or without DHA, then stimulated and co-cultured with freshly isolated neutrophils. When co-cultured with NK cells, neutrophils had higher expression levels of CD11b and CD47; secreted more IL-8, IL-1ra, and CXCL10; had increased phagocytic ability; and their apoptosis was increased early after initiation of the co-culture while dampened at a later time-point. Pre-incubation of NK cells with DHA attenuated NK cell-induced upregulation of CD11b and CD47 on neutrophils, had minor effects on NK cell induction of cytokine/chemokine secretion or their phagocytic ability. Neutrophils also affected the function of NK cells, lowering the frequency of NKp46+ and CXCR3+ NK cells and increasing the concentrations of IFN-γ, TNF-α, and GM-CSF in the co-cultures. Pre-incubation of NK cells with DHA further decreased the frequency of NKp46+ NK cells in the co-culture with neutrophils and decreased the concentrations of IFN-γ, CCL3 and GM-CSF. These findings indicate that NK cells have mostly pro-inflammatory effects on neutrophils and that DHA can attenuate some of these pro-inflammatory effects. Neutrophils had both anti- and pro-inflammatory effects on NK cells. When NK cells had been pre-treated with DHA, the anti-inflammatory effects were increased and some of the pro-inflammatory effects attenuated. Overall, the results suggest that DHA may lead to a more anti-inflammatory microenvironment for NK cell and neutrophil crosstalk.

Exopolysaccharides from Cyanobacterium aponinum induce a regulatory dendritic cell phenotype and inhibit SYK and CLEC7A expression in dendritic cells, T cells and keratinocytes.

Regular bathing in the Blue Lagoon has beneficial effects on psoriasis. Previously, we showed that exopolysaccharides (EPS-Ca) secreted by Cyanobacterium aponinum, a dominating organism in the Blue Lagoon, increased IL-10 secretion by human dendritic cells (DCs). In addition, co-culturing allogeneic CD4+ T cells with DCs matured in the presence of EPS-Ca increased differentiation of T cells into T regulatory cells at the cost of the disease inducing Th17 cells. In the present study, EPS-Ca increased the proportion of DCs expressing CD141, a surface molecule linked to regulatory DCs, and the CD141+ cells secreted more IL-10 than the CD141- cells. EPS-Ca decreased T cell secretion of IL-17, IL-13 and IL-10 and the proportion of T cells expressing the activation marker CD69 that has also been linked to lymphocyte retention. In addition, EPS-Ca reduced keratinocyte secretion of CCL20 and CXCL10, chemokines implicated in recruitment of inflammatory cells. EPS-Ca decreased DC expression of Dectin-1/CLEC7A and SYK, keratinocyte expression of CLEC7A, SYK and CAMP (the gene for LL37), and T cell expression of phosphorylated Zap70. These results indicate that EPS-Ca may induce a regulatory phenotype of DCs, T cells that are less active/inflammatory and less prone to being retained in the skin, and keratinocytes that induce less recruitment of inflammatory cells to the skin and that these effects may be mediated by the effects of EPS-Ca on CLEC7A and SYK. Overall the results indicate that EPS-Ca may be involved in the beneficial effects psoriasis patients experience when bathing in the Blue Lagoon.

Impact of dibenzocyclooctadiene lignans from Schisandra chinensis on the redox status and activation of human innate immune system cells.

Redox signaling has been established as an essential component of inflammatory responses, and redox active compounds are of interest as potential immunomodulatory agents. Dibenzocyclooctadiene lignans isolated from Schisandra chinensis, a medicinal plant with widespread use in oriental medicine, have been implicated to possess immunomodulatory properties but their effects on the human innate immune system cells have not been described. In this contribution, data are presented on the impact of schisandrin, schisandrin B and schisandrin C on human monocytic cell redox status, as well as their impact on dendritic cell maturation and T cell activation capacity and cytokine production. In THP-1 cells, levels of intracellular reactive oxygen species (ROS) were elevated after 1 h exposure to schisandrin. Schisandrin B and schisandrin C decreased cellular glutathione pools, which is a phenotype previously reported to promote anti-inflammatory functions. Treatment of human primary monocytes with the lignans during their maturation to dendritic cells did not have any effect on the appearance of surface markers HLA-DR and CD86 but schisandrin B and schisandrin C suppressed the secretion of cytokines interleukin (IL)-6, IL-10 and IL-12 by the mature dendritic cells. Dendritic cells maturated in presence of schisandrin C were further cocultured with naïve CD4+ T cells, resulting in reduced IL-12 production. In THP-1 cells, schisandrin B and schisandrin C reduced the IL-6 and IL-12 production triggered by E. coli lipopolysaccharide and IL-12 production induced by an infection with Chlamydia pneumoniae. In conclusion, the studied lignans act as immunomodulatory agents by altering the cytokine secretion, but do not interfere with dendritic cell maturation. And the observed effects may be associated with the ability of the lignans to alter cellular redox status.

Natural killer cells play an essential role in resolution of antigen-induced inflammation in mice.

This study examined whether NK cells are important for resolution of antigen-induced inflammation. C57BL/6 mice were immunized twice with methylated BSA (mBSA) and inflammation induced by intraperitoneal injection of mBSA. Mice were injected intravenously with anti-asialo GM1 (αASGM1) or a control antibody 24h prior to peritonitis induction and peritoneal exudate collected at different time points. Expression of surface molecules and apoptosis on peritoneal cells was determined by flow cytometry and concentration of chemokines, cytokines, soluble cytokine receptors and lipid mediators by ELISA and LC-MS/MS. Apoptosis in parathymic lymph nodes and spleens was determined by TUNEL staining. Mice administered αASGM1 had lower peritoneal NK cell numbers and a higher number of peritoneal neutrophils 12h after induction of inflammation than control mice. The number of neutrophils was still high in the αASGM1 treated mice when their number had returned to baseline levels in the control mice, 48h after induction of inflammation. Peritoneal concentrations of the neutrophil regulators G-CSF and IL-12p40 were higher at 12h in the αASGM1 treated mice than in the control mice, whereas concentrations of lipid mediators implicated in resolution of inflammation, i.e. LXA4 and PGE2, were lower. Reduced apoptosis was detected in peritoneal neutrophils as well as in draining lymph nodes and spleens from the αASGM1 treated mice compared with that in the control mice. In addition, αASGM1 treated mice had lower number of peritoneal NK cells expressing NKp46 and NKG2D, receptors implicated in NK cell-induced neutrophil apoptosis. Furthermore, αASGM1 treatment completely blocked the increase in CD27+ NK cells that occurred in control mice following induction of inflammation, but CD27+ NK cells have been suggested to have a regulatory role. These results indicate a crucial role for NK cells in resolution of antigen-induced inflammation and suggest their importance in tempering neutrophil recruitment and maintaining neutrophil apoptosis.

Oral biopsies from patients with orofacial granulomatosis with histology resembling Crohn's disease have a prominent Th1 environment.

BACKGROUND: Orofacial granulomatosis (OFG) is an idiopathic inflammatory disorder of children and young adults whose clinical symptoms include swelling of the lips or face, mucosal nodularity (cobblestoning), mucosal tags, hyperplasia of the gingivae, and aphthous oral ulcers. Whether some OFG patients with clinical and histological characteristics resembling Crohn's disease (CD) are a special group (oral CD) or true CD patients with symptoms reaching all the way to the oral mucosa remains to be determined. METHODS: In this study oral biopsies from 10 patients with OFG were analyzed for the presence of T cells, T-cell subsets, B cells, and macrophages, as well as cytokines (IL-4, IL-10, IFN-gamma, IL-12, and TNF-alpha), chemokines (RANTES and MIP-1alpha), and chemokine receptors (CCR3, CCR5, and CXCR3). For comparison, oral tissues from 7 patients with other granulomatous diseases were included. RESULTS: Compared with the non-OFG group, the OFG group had raised levels of CD4(+) T cells, IFN-gamma, IL-10, and RANTES but reduced levels of CD68(+) macrophages outside the granulomas, whereas within the granulomas the levels of CD3(+) and CD4(+) T cells and of IFN-gamma were raised, but the levels of IL-4 were decreased. These data are indicative of a Th1 environment within the oral OFG tissues, which resembles that already observed in gut CD tissues. CONCLUSIONS: Therefore, it can be concluded that some OFG patients have both histopathological and immunopathological features that resemble those observed in CD patients.

Immunomodulating effects of lichen-derived polysaccharides on monocyte-derived dendritic cells.

Many naturally occurring polysaccharides from fungi and lichens have been found to have immunomodulating activity. However, the majority of these studies have focused on their effects on the innate arm of the immune system. Although dendritic cells (DCs) belong to the innate immune system, they play an important role as a bridge between the innate and the adaptive immune response. In this study, the effects of 11 chromatographically purified and well-characterised lichen polysaccharides (of different structural types) on the maturation of DCs were tested by analysing the secretion of IL-12p40 and IL-10 by human monocyte-derived dendritic cells in vitro. Four of the polysaccharides upregulated IL-10 secretion by the dendritic cells, as compared with unstimulated cells, the beta-glucans lichenan and Ths-2 and the heteroglycans Pc-4 and thamnolan. IL-12p40 secretion was significantly upregulated by the beta-glucan lichenan and the heteroglycans Pc-2, Pc-4, thamnolan and Ths-4, while the mature dendritic cells stimulated with the heteroglycan Pc-1 secreted significantly less IL-12p40 than the unstimulated cells. Proportional index (PI) was used to determine the relationship between the IL-12p40 and IL-10 secretion. The PI of all the beta-glucans, i.e. lichenan, pustulan and Ths-2, and the heteroglycan thamnolan was significantly lower than the PI observed for the unstimulated cells, which was mainly due to increased IL-10 secretion. Therefore, these polysaccharides could be considered suitable candidates in tolerance and anti-inflammatory studies, as IL-10 is one of the major cytokines involved in tolerance and anti-inflammatory responses.