Sargachromenol Isolated from Sargassum horneri Inhibits Particulate Matter-Induced Inflammation in Macrophages through Toll-like Receptor-Mediated Cell Signaling Pathways.

Sargassum horneri is an invasive brown seaweed that grows along the shallow coastal areas of the Korean peninsula, which are potentially harmful to fisheries and natural habitats in the areas where it is accumulated. Therefore, the author attempted to evaluate the anti-inflammatory mechanism of Sargachromenol isolated from S. horneri against particulate matter (PM)-stimulated RAW 264.7 macrophages. PM is a potent inducer of respiratory diseases such as lung dysfunctions and cancers. In the present study, the anti-inflammatory properties of Sargachromenol were validated using enzyme-linked immunosorbent assay (ELISA), Western blots, and RT-qPCR experiments. According to the results, Sargachromenol significantly downregulated the PM-induced proinflammatory cytokines, Prostaglandin E2 (PGE2), and Nitric Oxide (NO) secretion via blocking downstream activation of Toll-like receptor (TLR)-mediated nuclear factor kappa B (NF-κB) and MAPKs phosphorylation. Thus, Sargachromenol is a potential candidate for innovation in various fields including pharmaceuticals, cosmeceuticals, and functional food.

Sargachromenol Purified from Sargassum horneri Inhibits Inflammatory Responses via Activation of Nrf2/HO-1 Signaling in LPS-Stimulated Macrophages.

In this study, we isolated sargachromenol (SC) from Sargassum horneri and evaluated its anti-inflammatory effect in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. SC did not show cytotoxicity at all concentrations and effectively increased the cell viability by reducing the nitric oxide (NO) and intracellular reactive oxygen species (ROS) production in LPS-stimulated RAW 264.7 macrophages. In addition, SC decreased the mRNA expression levels of inflammatory cytokines (IL-1ß, IL-6, and TNF-α) and inflammatory mediators (iNOS and COX-2). Moreover, SC suppressed the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) and mitogen-activated protein kinase (MAPK) signaling, whereas activated the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling in LPS-stimulated RAW 264.7 macrophages. Interestingly, the anti-inflammatory effect of SC was abolished by the inhibition of HO-1 in LPS-stimulated RAW 264.7 macrophages. According to the results, this study suggests that the antioxidant capacity of SC leads to its anti-inflammatory effect and it potentially may be utilized in the nutraceutical and pharmaceutical sectors.

Polyphenol containing Sargassum horneri attenuated Th2 differentiation in splenocytes of ovalbumin-sensitised mice: involvement of the transcription factors GATA3/STAT5/NLRP3 in Th2 polarization.

CONTEXT: Sargassum horneri (Turner) C. Agardh (Sargassaceae) is a brown marine alga used in oriental medicine to treat allergic conditions. OBJECTIVE: This study clarifies the effect of polyphenol-containing S. horneri ethanol extract (SHE) on T-helper type-2 (Th2) polarisation. MATERIALS AND METHODS: All mice (BALB/c mice, n = 12) except in the healthy control group were first sensitised with an intraperitoneal injection of ovalbumin (OVA; 20 µg) and alum (2 mg) on Day 0 and Day 14. Similarly, phosphate-buffered saline (PBS) was injected according to the same schedule into the healthy control mice. After the final administration, splenocytes were obtained. OVA sensitised mice were challenged with OVA (100 µg/mL) in the absence or presence (62.5 and 125 µg/mL) of SHE while healthy control group remained untreated. RESULTS: SHE (0-1000 µg/mL) was not cytotoxic to splenocytes and demonstrated IC50 values of 3.27 and 3.92 mg/mL, respectively, at 24 and 48 h of incubation. SHE suppressed cell proliferation at concentrations ≥62.5 µg/mL. SHE treatment (125 µg/mL) subdued (by 1.8-fold) the population expansion of CD3+CD4+ helper T cells induced by OVA challenge. SHE attenuated the OVA-induced activation of respective transcription factors GATA3 and NLRP3. Simultaneously, highly elevated levels of cytokines interleukin (IL)-4 and IL-5 caused by OVA stimulation were removed completely and IL-13 suppressed by 1.5-fold. CONCLUSIONS: SHE exhibits Th2 immune suppression under OVA stimulation via GATA3- and NLRP3-dependent IL-4, IL-5, and IL-13 suppression. Therefore, SHE could be therapeutically useful for alleviating the symptoms of allergen-mediated immune diseases.

Pyk2 downstream of G12/13 pathways regulates platelet shape change through RhoA/p160ROCK.

Rho/Rho-kinase downstream of G12/13 plays an important role in the regulation of calcium-independent platelet shape change. We have previously shown that proline-rich tyrosine kinase 2 (Pyk2) is activated downstream of G12/13 pathways. In this study, we evaluated the role of Pyk2 in G12/13-induced platelet shape change. We used low concentrations of YFLLRNP, a heptapeptide binding to protease-activated receptor 1 (PAR1), or PAR4-activating peptide AYPGKF in the presence of Gαq inhibitor YM254890 to selectively stimulate G12/13 pathways. We found that G12/13-induced platelet shape change was completely inhibited in the presence of Pyk2 inhibitors AG17 and TAT-Pyk2-CT, suggesting an important role of Pyk2 in platelet shape change. In addition, AYPGKF-induced shape change in Gq -/- platelets was completely inhibited in the presence of AG17 or RhoA/p160ROCK inhibitor Y27632, confirming the role of Pyk2 in RhoA-dependent shape change. Furthermore, AYPGKF-induced platelet aggregation and dense granule secretion were inhibited by blocking Pyk2 or RhoA. Finally, G12/13-induced myosin phosphatase target subunit 1 (MYPT1) phosphorylation was inhibited by AG17, confirming that Pyk2 regulates RhoA/p160ROCK activation in platelets. These results demonstrate that Pyk2 downstream of G12/13 pathways regulates platelet shape change as well as platelet aggregation and dense granule secretion through the regulation of RhoA/p160ROCK.

Sargassum horneri as a Functional Food Ameliorated IgE/BSA-Induced Mast Cell Activation and Passive Cutaneous Anaphylaxis in Mice.

Sargassum horneri (S. horneri), an edible brown alga, has been proposed as a functional food with an improvement effect on abnormal skin immune responses. The present study investigates the anti-allergic effect of an ethanol extract from S. horneri (SHE) on immunoglobulin E (IgE)/bovine serum albumin (BSA)-mediated activation in bone marrow-derived cultured-mast cells (BMCMCs) and passive cutaneous anaphylaxis (PCA) reaction in mice. SHE markedly and dose-dependently suppressed the degranulation of BMCMCs by reducing the ß-hexosaminidase and histamine release without cytotoxicity. In addition, SHE significantly decreased the FcεRI expression on the surface of BMCMCs and its IgE binding. Moreover, SHE reduced the mRNA expression and the production of allergic cytokines; interleukin (IL)-1ß, IL-4, IL-5, IL-6, IL-10, IL-13; interferon (IFN)-γ and/or tumor necrosis factor (TNF)-α; and a chemokine, thymus and activation-regulated chemokine (TARC), by suppressing the activation of Src-family kinases and nuclear factor (NF)-κB signaling. In further study, the application of SHE reduced the PCA reaction in an IgE/BSA-induced type I allergic mice model. Taken together, we suggest that SHE has an anti-allergic effect in type I allergic responses.

Mojabanchromanol Isolated from Sargassum horneri Attenuates Particulate Matter Induced Inflammatory Responses via Suppressing TLR2/4/7-MAPK Signaling in MLE-12 Cells.

Chromanols from marine algae are studied for drug development due to its prominent bioactive properties, and mojabanchromanol (MC), a chromanol isolated from a brown algae Sargassum horneri, is found to possess anti-oxidant potential. In this study, we hypothesized MC may attenuate particulate matter (PM)-induced and reactive oxygen species (ROS)-mediated inflammatory responses in airways and tried to identify its potential and underlying mechanism against PM (majority <2.5 µm in diameter)-induced inflammatory responses in a lung type II alveolar epithelial cell line, MLE-12. MC attenuated PM-induced malondialdehyde (MDA), a lipid peroxidation end product, and 8-hydroxydeoxyguanosine (8-OHdG), the most representative DNA oxidative damage product, further validating MC's potential in attenuating PM-induced oxidative stress. MC also suppressed PM-triggered TLR2/4/7 activation in MLE-12 cells. Moreover, MC reduced ROS-mediated phosphorylation of mitogen-activated protein kinase (MAPK) extracellular signal-regulated kinase 1/2 (Erk1/2) and c-Jun NH (2)-terminal kinase (JNK) that were also activated in PM exposed cells. MC further inhibited the secretion of pro-inflammatory cytokines (IL-6, IL-1ß and IL-33) in MLE-12 cells exposed to PM. These results provide a clear evidence for MC's potential in attenuating PM-triggered inflammatory responses in MLE-12 cells via repressing TLR2/4/7 and MAPK signaling. Therefore, MC can be developed as a therapeutic agent against PM induced airway inflammatory responses.

Characterization of Integrin αIIbß3-Mediated Outside-in Signaling by Protein Kinase Cδ in Platelets.

Engagement of integrin αIIbß3 promotes platelet-platelet interaction and stimulates outside-in signaling that amplifies activation. Protein kinase Cδ (PKCδ) is known to play an important role in platelet activation, but its role in outside-in signaling has not been established. In the present study, we determined the role of PKCδ and its signaling pathways in integrin αIIbß3-mediated outside-in signaling in platelets using PKCδ-deficient platelets. Platelet spreading to immobilized fibrinogen resulted in PKCδ phosphorylation, suggesting that αIIbß3 activation caused PKCδ activation. αIIbß3-mediated phosphorylation of Akt was significantly inhibited in PKCδ -/- platelets, indicating a role of PKCδ in outside-in signaling. αIIbß3-mediated PKCδ phosphorylation was inhibited by proline-rich tyrosine kinase 2 (Pyk2) selective inhibitor, suggesting that Pyk2 contributes to the regulation of PKCδ phosphorylation in outside-in signaling. Additionally, Src-family kinase inhibitor PP2 inhibited integrin-mediated Pyk2 and PKCδ phosphorylation. Lastly, platelet spreading was inhibited in PKCδ -/- platelets compared to the wild-type (WT) platelets, and clot retraction from PKCδ -/- platelets was markedly delayed, indicating that PKCδ is involved in the regulation of αIIbß3-dependent interactivities with cytoskeleton elements. Together, these results provide evidence that PKCδ plays an important role in outside-in signaling, which is regulated by Pyk2 in platelets.

Role of GRK6 in the Regulation of Platelet Activation through Selective G Protein-Coupled Receptor (GPCR) Desensitization.

Platelet G protein-coupled receptors (GPCRs) regulate platelet function by mediating the response to various agonists, including adenosine diphosphate (ADP), thromboxane A2, and thrombin. Although GPCR kinases (GRKs) are considered to have the crucial roles in most GPCR functions, little is known regarding the regulation of GPCR signaling and mechanisms of GPCR desensitization by GRKs in platelets. In this study, we investigated the functional role of GRK6 and the molecular basis for regulation of specific GPCR desensitization by GRK6 in platelets. We used GRK6 knockout mice to evaluate the functional role of GRK6 in platelet activation. Platelet aggregation, dense- and -granule secretion, and fibrinogen receptor activation induced by 2-MeSADP, U46619, thrombin, and AYPGKF were significantly potentiated in GRK6-/- platelets compared to the wild-type (WT) platelets. However, collagen-related peptide (CRP)-induced platelet aggregation and secretion were not affected in GRK6-/- platelets. Interestingly, platelet aggregation induced by co-stimulation of serotonin and epinephrine which activate Gq-coupled 5HT2A and Gz-coupled 2A adrenergic receptors, respectively, was not affected in GRK6-/- platelets, suggesting that GRK6 was involved in specific GPCR regulation. In addition, platelet aggregation in response to the second challenge of ADP and AYPGKF was restored in GRK6-/- platelets whereas re-stimulation of the agonist failed to induce aggregation in WT platelets, indicating that GRK6 contributed to P2Y1, P2Y12, and PAR4 receptor desensitization. Furthermore, 2-MeSADP-induced Akt phosphorylation and AYPGKF-induced Akt, extracellular signal-related kinase (ERK), and protein kinase Cδ (PKC) phosphorylation were significantly potentiated in GRK6-/- platelets. Finally, GRK6-/- mice exhibited an enhanced and stable thrombus formation after FeCl3 injury to the carotid artery and shorter tail bleeding times, indicating that GRK6-/- mice were more susceptible to thrombosis and hemostasis. We conclude that GRK6 plays an important role in regulating platelet functional responses and thrombus formation through selective GPCR desensitization.

The Role of Fucoidans Isolated from the Sporophylls of Undaria pinnatifida against Particulate-Matter-Induced Allergic Airway Inflammation: Evidence of the Attenuation of Oxidative Stress and Inflammatory Responses.

Ambient particulate matter (PM) is a critical environment pollutant that promotes the onset and aggravation of respiratory diseases such as asthma through airway inflammation and hypersecretion of mucus. In this study, we aimed to identify the effects of fucoidans isolated from sporophylls of Undaria pinnatifida on asthma symptoms such as the inflammatory response and mucus secretion using a mouse model. Balb/c mice, intraperitoneally sensitized with ovalbumin (OVA, 10 µg) dissolved in 200 µL saline and 2 mg Al(OH)3, were exposed to PM (5 mg/m3) for 7 consecutive days. In parallel, along with PM exposure, we orally administrated fucoidans (100, 400 mg/Kg) or prednisone (5 mg/Kg), an anti-inflammatory drug. We found that oral administration of fucoidans significantly attenuated PM-induced lipid peroxidation and infiltration of inflammatory cells like F4/80+ macrophages, Gr-1+ granulocytes, and CD4+ T lymphocytes. Fucoidans also attenuated the level of PM-exacerbated IL-4, a primitive cytokine released in Th2 mediated eosinophilic asthma. This further suppressed mast cell activation, degranulation and IgE synthesis of PM exposed mice. Interestingly, fucoidans attenuated PM-exacerbated mucus hypersecretion and goblet cell hyperplasia. Therefore, our results suggest that fucoidans are effective at alleviating PM-exacerbated allergic asthma symptoms by attenuating the airway inflammatory response and mucus hypersecretion.

Jeju ground water containing vanadium induces normal T cell development and immune activation in chronically stressed mice.

Containing high concentration of vanadium served by the volcanic bedrock, Jeju ground water has long been known for various implicit health benefits including immune-promotion. Exposure to stress has been reported to be associated with immunosuppression such as reducing lymphocyte population or antibody production due to stress hormones. In this study, we aimed at evaluating the effects of Jeju ground water on chronically stressed mice. C57BL/6 mice were subjected to various stressors such as restraint stress, water swimming stress, heat stress, acoustic stress, and Jeju ground water was supplied for 28 days with two different concentrations, S1 (vanadium 15-20 µg/l, pH 8.3) and S2 (vanadium 20-25 µg/l, pH 8.5). Treatment with Jeju ground water increased CD4+CD8- or CD4-CD8+ single-positive thymocytes. It also increased the proliferation of splenocytes and the populations of CD4+ T cells, CD45R/B220+ B cells, CD11b+ macrophages or Gr-1+ granulocytes in spleen. In addition, the production of IgG was increased in chronically stressed mice by treatment with Jeju ground water. These results suggest vanadium-rich Jeju ground water may be helpful in T cell development in thymus and immune cell proliferation and its function in spleen against chronic stress.

Mucosal Immunity Related to FOXP3+ Regulatory T Cells, Th17 Cells and Cytokines in Pediatric Inflammatory Bowel Disease.

BACKGROUND: We aimed to investigate mucosal immunity related to forkhead box P3 (FOXP3+) regulatory T (Treg) cells, T helper 17 (Th17) cells and cytokines in pediatric inflammatory bowel disease (IBD). METHODS: Mucosal tissues from terminal ileum and colon and serum samples were collected from twelve children with IBD and seven control children. Immunohistochemical staining was done using anti-human FOXP3 and anti-RORγt antibodies. Serum levels of cytokines were analyzed using a multiplex assay covering interleukin (IL)-1ß, IL-4, IL-6, IL-10, IL-17A/F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, interferon (IFN)-γ, soluble CD40L, and tumor necrosis factor-α. RESULTS: FOXP3+ Treg cells in the lamina propria (LP) of terminal ileum of patients with Crohn's disease were significantly (P < 0.05) higher than those in the healthy controls. RORγt+ T cells of terminal ileum tended to be higher in Crohn's disease than those in the control. In the multiplex assay, serum concentrations (pg/mL) of IL-4 (9.6 ± 1.5 vs. 12.7 ± 3.0), IL-21 (14.9 ± 1.5 vs. 26.4 ± 9.1), IL-33 (14.3 ± 0.9 vs. 19.1 ± 5.3), and IFN-γ (15.2 ± 5.9 vs. 50.2 ± 42.4) were significantly lower in Crohn's disease than those in the control group. However, serum concentration of IL-6 (119.1 ± 79.6 vs. 52.9 ± 39.1) was higher in Crohn's disease than that in the control. Serum concentrations of IL-17A (64.2 ± 17.2 vs. 28.3 ± 10.0) and IL-22 (37.5 ± 8.8 vs. 27.2 ± 3.7) were significantly higher in ulcerative colitis than those in Crohn's disease. CONCLUSION: Mucosal immunity analysis showed increased FOXP3+ T reg cells in the LP with Crohn's disease while Th17 cell polarizing and signature cytokines were decreased in the serum samples of Crohn's disease but increased in ulcerative colitis.

Sargassum horneri (Turner) C. Agardh ethanol extract inhibits the fine dust inflammation response via activating Nrf2/HO-1 signaling in RAW 264.7 cells.

BACKGROUND: Among the different kinds of pollution, air pollution continues to increase globally. East Asia is considered to be significantly affected. As a result, the populations in these regions face serious health issues including respiratory disorders. This study investigated the impact of fine dust (FD) particles (CRM No. 28) on macrophage cells as a model for alveolar lung cells. METHODS: The research focused on inflammation and oxidative stress induced by FD and Sargassum horneri (Turner) C. Agardh ethanol extract (SHE) as a potential treatment. S. horneri is a type of brown algae that has demonstrated anti-inflammatory effects against RAW 264.7 macrophages in previous studies. MTT, Griess, ELISA, western blotting, and mRNA expression analyses using PCR techniques were used in this study. RESULTS: The optimum FD concentration was determined to be 125 µg mL- 1. FD particles stimulated inflammatory mediators production (iNOS, COX-2, and PGE2) and pro-inflammatory cytokines (IL-1ß, IL-6, and TNF-α), leading to NO production. These mediators were dose-dependently downregulated by treatment with SHE. IL-6 and TNF-α were identified as biomarkers for FD. SHE treatment induced HO-1 and Nrf2 activity in a dose-dependent manner under FD stimulation. This confirmed the cytoprotective effect against oxidative stress induced via FD. Furthermore, treatment of the cells with a p38 MAPK inhibitor (SB202190) induced FD-stimulated NO production. CONCLUSIONS: The results suggest that SHE increases macrophage cellular resistance to FD-induced inflammation and oxidative stress, probably via the p38 MAPK pathway and Nrf2/HO-1 expression.

Immunostimulatory effect of pepsin enzymatic extract from Porphyra yezoensis on murine splenocytes.

BACKGROUND: Porphyra yezoensis is a red alga consumed mainly in Korea, Japan, and China for food. This study researches the immunological effect of pepsin extract of P. yezoensis (PPEE) on murine splenocytes. RESULTS: PPEE was not toxic on murine splenocytes and dramatically increased the proliferation of splenocytes compared with untreated control. Flow cytometry assay performed to sum up the effect of PPEE (31.3 and 62.5 µg mL-1 ) on major immune cells revealed that PPEE had no effect on the function of CD3e+ CD4+ T-helper cells, CD3e+ CD8+ T-cytotoxic cells, or CD44+ CD62L- effector T cells in splenocytes compared with untreated control. More importantly, CD45+ CD11b+ macrophage and dendritic cell populations and Ly-6C+ Ly-6G+ macrophages/monocytes in splenocytes were activated by PPEE treatment compared with untreated control. Further experiments showed that PPEE treatment increased the secretion of macrophage-derived cytokines such as interleukin-1ß, tumor necrosis factor-α, and interleukin-12, and macrophage-activating cytokines interferon-γ and interleukin-10 compared with untreated control. CONCLUSION: Taken together, these results suggest that PPEE has an immune stimulatory effect on macrophages, dendritic cells, and memory T cells. This property signifies the potential medicinal value of PPEE in clinical implications for immune-compromised diseases. © 2017 Society of Chemical Industry.

Beetroot (Beta vulgaris) rescues mice from γ-ray irradiation by accelerating hematopoiesis and curtailing immunosuppression.

CONTEXT: Beetroot [Beta vulgaris Linné (Chenopodiaceae)], a vegetable usually consumed as a food or a medicinal plant in Europe, has been reported to have antioxidant and anti-inflammatory properties. Since the lymphohematopoietic system is the most sensitive tissue to ionizing radiation, protecting it from radiation damage is one of the best ways to decrease detrimental effects from radiation exposure. OBJECTIVE: In this study, we evaluated the radio-protective effects of beetroot in hematopoietic stem cells (HSCs) and progenitor cells. MATERIALS AND METHODS: Beetroot extract was administered at a dose of 400 mg/mouse per os (p.o.) three times into C57BL/6 mice and, at day 10 after γ-ray irradiation, diverse molecular presentations were measured and compared against non-irradiated and irradiated mice with PBS treatments. Survival of beetroot-fed and unfed irradiated animal was also compared. RESULTS: Beetroot not only stimulated cell proliferation, but also minimized DNA damage of splenocytes. Beetroot also repopulated S-phase cells and increased Ki-67 or c-Kit positive cells in bone marrow. Moreover, beetroot-treated mice showed notable boosting of differentiation of HSCs into burst-forming units-erythroid along with increased production of IL-3. Also, beetroot-treated mice displayed enhancement in the level of hematocrit and hemoglobin as well as the number of red blood cell in peripheral blood. Beetroot diet improved survival rate of lethally exposed mice with a dose reduction factor (DRF) of 1.1. DISCUSSION AND CONCLUSION: These results suggest that beetroot has the potency to preserve bone marrow integrity and stimulate the differentiation of HSCs against ionizing radiation.

Citrus hallabong [(Citrus unshiu × C. sinensis) × C. reticulata)] exerts potent anti-inflammatory properties in murine splenocytes and TPA-induced murine ear oedema model.

CONTEXT: Hallabong [(Citrus unshiu × C. sinensis) X C. reticulata)] (Rutaceae) is a hybrid citrus cultivated in temperate regions of South Korea. Its fruit is well-known for pharmacological properties. OBJECTIVE: This study examined the anti-inflammatory effect of 80% ethanol extract of Hallabong (HE) on concanavalin A (Con A)-stimulated splenocytes and mouse oedema model induced by 12-O-tetradecanoylphorbal acetate (TPA). MATERIALS AND METHODS: Murine splenocytes treated with HE were stimulated with Con A (10 µg/mL, for 24 h) were evaluated for T-cell population and production of inflammatory cytokines IL-2, IL-4 and IFN-γ. Anti-inflammatory effect of topically applied HE (100 µg/20 µL) on TPA (4 µg/20 µL/ear)-induced ear oedema was investigated in mouse model. RESULTS: HE-treated Con A-stimulated murine splenocytes showed a marked decrease in CD44/CD62L+ memory T-cell population, an important marker for anti-inflammatory activity, and a significant inhibition in the production of IL-2 and IFN-γ. HE treatment had reduced the mouse skin oedema (47%) and myeloperoxidase (MPO) activity significantly (40%) in TPA-challenged tissues. More importantly, immunohistochemical localization revealed the suppressed (p < 0.05) expression of inducible nitric oxide (iNOS), cyclooxygenase-2 (COX2). HE decreased the infiltration of CD3+ T cells and F4/80+ macrophages to the site of inflammation and a topical application of HE significantly suppressed the expression of TNF-α (20.2%). DISCUSSION AND CONCLUSION: A topical application of HE can exert a potential anti-inflammatory effect and HE can be explored further as a putative alternative therapeutic agent for inflammatory oedema.

Lipocalin-2 protein deficiency ameliorates experimental autoimmune encephalomyelitis: the pathogenic role of lipocalin-2 in the central nervous system and peripheral lymphoid tissues.

Lipocalin-2 (LCN2) plays an important role in cellular processes as diverse as cell growth, migration/invasion, differentiation, and death/survival. Furthermore, recent studies indicate that LCN2 expression and secretion by glial cells are induced by inflammatory stimuli in the central nervous system. The present study was undertaken to examine the regulation of LCN2 expression in experimental autoimmune encephalomyelitis (EAE) and to determine the role of LCN2 in the disease process. LCN2 expression was found to be strongly increased in spinal cord and secondary lymphoid tissues after EAE induction. In spinal cords astrocytes and microglia were the major cell types expressing LCN2 and its receptor 24p3R, respectively, whereas in spleens, LCN2 and 24p3R were highly expressed in neutrophils and dendritic cells, respectively. Furthermore, disease severity, inflammatory infiltration, demyelination, glial activation, the expression of inflammatory mediators, and the proliferation of MOG-specific T cells were significantly attenuated in Lcn2-deficient mice as compared with wild-type animals. Myelin oligodendrocyte glycoprotein-specific T cells in culture exhibited an increased expression of Il17a, Ifng, Rorc, and Tbet after treatment with recombinant LCN2 protein. Moreover, LCN2-treated glial cells expressed higher levels of proinflammatory cytokines, chemokines, and MMP-9. Adoptive transfer and recombinant LCN2 protein injection experiments suggested that LCN2 expression in spinal cord and peripheral immune organs contributes to EAE development. Taken together, these results imply LCN2 is a critical mediator of autoimmune inflammation and disease development in EAE and suggest that LCN2 be regarded a potential therapeutic target in multiple sclerosis.

The JNk/NFkappaB pathway is required to activate murine lymphocytes induced by a sulfated polysaccharide from Ecklonia cava.

BACKGROUND: The proven immunomodulatory and immune system activating properties of Ecklonia cava (E. cava) have been attributed to its plentiful polysaccharide content. Therefore, we investigated whether the sulfated polysaccharide (SP) of E. cava specifically activates the protein kinases (MAPKs) and nuclear factor-kappaB (NFkappaB) to incite immune responses. METHODS: To assess immune responsiveness, lymphocytes were isolated from spleens of ICR mice and cultured with SP and its inhibitors. Assays included 3H-thymidine incorporation, flow cytometry, real time polymerase chain reaction (rtPCR), enzyme linked immunosorbent assay (ELISA), intracellular cytokine assay. Western blot, and electrophoretic mobility shift assay (EMSA). RESULTS: SP dose-dependently increased the proliferation of lymphocytes without cytotoxicity. In particular, SP markedly enhanced the proliferation and differentiation of CD3+ mature T cells and CD45R/B220+ pan B cells. Additionally, SP increased the expression and/or production of IL-2, IgG(1a), and IgG(2b) compared to that in untreated cells. The subsequent application of JNK (SP600125), NFkappaB (PDTC), and serine protease (TPCK) inhibitors significantly inhibited the proliferation and IL-2 production of SP-treated lymphocytes as well as the phosphorylation of JNK and IkappaB, the activation of nuclear NFkappaB p65, and binding of NFkappaB p65 DNA. Moreover, co-application of both JNK and NFkappaB inhibitors completely blocked the proliferation of lymphocytes even in the presence of SP. CONCLUSION: These results suggest that SP induced T and B cell responses via both JNK and NFkappaB pathways. GENERAL SIGNIFICANCE: The effect of SP on splenic lymphocyte activation was assayed here for the first time and indicated the underlying functional mechanism.

High sucrose intake exacerbates airway inflammation through pathogenic Th2 and Th17 response in ovalbumin (OVA)-induced acute allergic asthma in C57BL/6 mice.

Asthma is an inflammatory disease characterized by chronic inflammation in lung tissues and excessive mucus production. High-fat diets have long been assumed to be a potential risk factor for asthma. However, to date, very few direct evidence indicating the involvement of high sucrose intake (HSI) in asthma progression exists. In this study, we investigate the effect of HSI on ovalbumin (OVA)-sensitized allergic asthma mice. We observed that HSI increased the expression of inflammatory genes (IL-1ß, IL-6, TNF-α) in adipose tissues and led to reactive oxygen species generation in the liver and lung. In addition, HSI accelerated the TLR4/NF-κB signaling pathway leading to MMP9 activation, which promotes the chemokines and TGF-ß secretion in the lungs of OVA-sensitized allergic asthma mice. More importantly, HSI significantly promoted the pathogenic Th2 and Th17 responses. The increase of IL-17A secretion by HSI increased the expression of chemokines (MCP-1, CXCL1, CXCL5, CXCL8). It resulted in eosinophil and mast cell infiltration in the lung and trachea. We also demonstrated that HSI increased mucus hypersecretion, which was validated by increased main mucin protein (MUC5AC) secreted in the lungs. Our findings suggest that HSI exacerbates the development of Th2/Th17-predominant asthma by upregulating the TLR4-mediated NF-κB pathway, leading to excessive MMP9 production.

High-Sucrose Diet Accelerates Arthritis Progression in a Collagen-Induced Rheumatoid Arthritis Model.

SCOPE: High dietary sugar and sweeteners are suspected to cause the development of rheumatoid arthritis (RA) symptoms through the induction of proinflammatory cytokine release. However, the mechanisms by which increased dietary sugar affects RA etiology are not yet fully understood. The study uses a mouse model of collagen-induced RA (CIA) to investigate the relationship between excessive sugar consumption and RA risk. METHODS AND RESULTS: RA-associated pathological features are assessed in the nonimmunized (NI) control group, the CIA-positive control group, and the CIA + high-sucrose diet (CIA+HS, 63% calories from sucrose) group. Compared with the CIA group, the CIA+HS group shows a greater increase in paw thickness and clinical scores, as well as, a higher degree of pannus formation and inflammation in the knee, ankle, and sole tissues. Moreover, the infiltration of immune cells is increased in the CIA+HS group. Although the expression of hepatic lipogenic genes, is not altered, that of toll-like receptor (TLR4) and IL-1ß is considerably elevated in the CIA+HS group. CONCLUSIONS: These findings suggest that excessive sucrose consumption causes hepatic fibrosis and inflammation, contributing to the pathophysiology of RA.

Oral Administration of Sargassum horneri Suppresses Particulate Matter-Induced Oxidative DNA Damage in Alveolar Macrophages of Allergic Airway Inflammation: Relevance to PM-Mediated M1/M2 AM Polarization.

SCOPE: Particulate matter (PM) can cause cellular oxidative damage and promote respiratory diseases. It has recently shown that Sargassum horneri ethanol extract (SHE) containing sterols and gallic acid reduces PM-induced oxidative stress in mice lung cells through ROS scavenging and metal chelating. In this study, the role of alveolar macrophages (AMs) is identified that are particularly susceptible to DNA damage due to PM-triggered oxidative stress in lungs of OVA-sensitized mice exposed to PM. METHODS AND RESULTS: The study scrutinizes if PM exposure causes oxidative DNA damage to AMs differentially depending on their type of polarization. Further, SHE's potential is investigated in reducing oxidative DNA damage in polarized AMs and restoring AM polarization in PM-induced allergic airway inflammation. The study discovers that PM triggers prolonged oxidative stress to AMs, leading to lipid peroxidation in them and alveolar epithelial cells. Particularly, AMs are polarized to M2 phenotype (F4/80+ CD206+ ) with enhanced oxidative DNA damage when subject to PM-induced oxidative stress. However, SHE repairs oxidative DNA damage in M1- and M2-polarized AMs and reduces AMs polarization imbalance due to PM exposure. CONCLUSION: These results suggest the possibility of SHE as beneficial foods against PM-induced allergic airway inflammation via suppression of AM dysfunction.