Saeromi Kang

Sphingosine 1-phosphate induced anti-atherogenic and atheroprotective M2 macrophage polarization through IL-4 ☆

Sphingosine 1-phosphate (S1P) has been implicated in anti-atherogenic properties of high-density lipoproteins. However, the roles and signaling of S1P in macrophages, the main contributor to atherosclerosis, have not been well studied. Furthermore, pro-inflammatory M1 and anti-inflammatory M2 macrophage phenotypes may influence the development of atherosclerosis. Therefore, we investigated the effects of S1P on macrophage phenotypes, especially on M2 polarization and its signaling in relation to the anti-atherogenic properties of S1P. It was found that S1P induced anti-inflammatory M2 polarization via IL-4 secretion and its signaling, and induced IL-4Rα and IL-2Rγ. In addition, down-stream signalings, such as, stat-6 phosphorylation, SOCS1 induction, and SOCS3 suppression were also observed in macrophages in response to S1P. Furthermore, S1P-induced ERK activation, and the inhibitions of p38 MAPK and JNK were found to be key signals for IL-4 induction. Moreover, the anti-atherogenic effect of S1P in HDL was confirmed by the observation that oxidized LDL-induced lipid accumulation was attenuated in S1P-treated M2 macrophages. Furthermore, the atheroprotective effect of S1P was demonstrated by its anti-apoptotic effect on S1P-treated macrophages. The present study shows that S1P-induced M2 polarization of macrophages could be mediated via IL-4 signaling, and suggests that M2 polarization by S1P is responsible for the anti-atherogenic and atheroprotective properties of high-density lipoproteins in vivo.

Lysophosphatidylethanolamine utilizes LPA1 and CD97 in MDA-MB-231 breast cancer cells

Lysophosphatidylethanolamine (LPE) is a lyso-type metabolite of phosphatidylethanolamine (a plasma membrane component), and its intracellular Ca(2+) ([Ca(2+)]i) increasing actions may be mediated through G-protein-coupled receptor (GPCR). However, GPCRs for lysophosphatidic acid (LPA), a structurally similar representative lipid mediator, have not been implicated in LPE-mediated activities in SK-OV3 or OVCAR-3 ovarian cancer cells or in receptor over-expression systems. In the present study, LPE-induced [Ca(2+)]i increase was observed in MDA-MB-231 cells but not in other breast cancer cell lines. In addition, LPE- and LPA-induced responses showed homologous and heterologous desensitization. Furthermore, VPC32183 and Ki16425 (antagonists of LPA1 and LPA3) inhibited LPE-induced [Ca(2+)]i increases, and knockdown of LPA1 by transfection with LPA1 siRNA completely inhibited LPE-induced [Ca(2+)]i increases. Furthermore, the involvement of CD97 (an adhesion GPCR) in the action of LPA1 in MDA-MB-231 cells was demonstrated by siRNA transfection. Pertussis toxin (a specific inhibitor of Gi/o proteins), edelfosine (an inhibitor of phospholipase C), or 2-APB (an inhibitor of IP3 receptor) completely inhibited LPE-induced [Ca(2+)]i increases, whereas HA130, an inhibitor of autotaxin/lysophospholipase D, did not. Therefore, LPE is supposed to act on LPA1-CD97/Gi/o proteins/phospholipase C/IP3/Ca(2+) rise in MDA-MB-231 breast cancer cells.

Anti-allergic and anti-inflammatory effects of bakkenolide B isolated from Petasites japonicus leaves.

AIMS OF THE STUDY To elucidate the anti-allergic and anti-inflammatory effects of Petasites genus, we studied the effects of several compounds isolated from Petasites japonicas leaves. MATERIALS AND METHODS Bakkenolide B was isolated from Petasites japonicus leaves. Antigen-induced degranulation was measured in RBL-2H3 mast cells by measuring β-hexosamidase activity. Induction of inducible nitric oxide synthase and cyclooxygenase 2 was measured by Western blotting in peritoneal macrophages. Ovalbumin-induced asthma model was used for in vivo efficacy test of bakkanolide B. RESULTS We found that bakkenolide B, a major component of the leaves, concentration-dependently inhibited RBL-2H3 mast cell degranulation. Bakkenolide B also inhibited the gene inductions of inducible nitric oxide synthase and cyclooxygenase 2 in mouse peritoneal macrophages. Furthermore, in an ovalbumin-induced asthma model, bakkenolide B strongly inhibited the accumulation of eosinophils, macrophages, and lymphocytes to bronchoalveolar lavage fluid. CONCLUSION Bakkenolide B has suppressive properties for allergic and inflammatory responses and may be utilized as a potent agent for the treatment of asthma.

Identification of a novel anti-inflammatory compound, α-cubebenoate from Schisandra chinensis.

AIMS OF THE STUDY Extracts of Schisandra chinensis have been used as an anti-fatigue and tonic agent. Because chronic fatigue syndrome is related to inflammatory and oxidative stress, we assessed whether Schisandra chinensis has anti-inflammatory constituents and studied the effect of a novel α-cubebenoate isolated from Schisandra chinensis. MATERIALS AND METHODS α-Cubebenoate was isolated from an extract of Schisandra chinensis fruits. The inductions of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) by lipopolysaccharide (LPS) were quantified by RT-PCR and Western blotting in mouse peritoneal macrophages. Nitric oxide (NO) and prostaglandin E2 (PGE2) were also measured in the media by Griess reagent and EIA method. A mouse model of LPS-induced peritonitis was used to test the in vivo efficacy of α-cubebenoate. RESULTS α-Cubebenoate (5-10μg/ml) inhibited the inductions of iNOS and COX-2 in mouse peritoneal macrophages at the mRNA and protein levels. LPS-induced productions of NO and PGE2 were inhibited by α-cubebenoate (5-10μg/ml). In addition, α-cubebenoate inhibited the LPS-induced activation of JNK, but not those of ERK and p38 MAPK in mouse peritoneal macrophages. Furthermore, in the LPS-induced in vivo peritonitis model, α-cubebenoate (1mg/kg) strongly inhibited the accumulation of polymorph nuclear lymphocytes in the peritoneal cavity. CONCLUSION α-Cubebenoate inhibited LPS-induced expression of iNOS and COX-2 in a concentration-dependent manner, thereby suppressing productions of NO and PGE2 in vitro in peritoneal macrophages. α-Cubebenoate also inhibited LPS-induced accumulation of polymorph nuclear lymphocytes in LPS-induced peritonitis model in vivo. α-Cubebenoate may act as an anti-fatigue constituent of Schisandra chinensis through anti-inflammation and could be of therapeutic use as a treatment for inflammatory diseases.

Anti-allergic effect of α-cubebenoate isolated from Schisandra chinensis using in vivo and in vitro experiments.

AIM OF THE STUDY In Oriental countries, the dried fruits of Schisandra chinensis are extensively used in traditional medicine to treat asthma, gonorrhea, and other diseases. Recently, α-cubebenoate was isolated as an anti-inflammatory component from Schisandra chinensis. In the present study, the authors examined the anti-allergic effect of α-cubebenoate using in vivo and in vitro experiments. MATERIALS AND METHODS α-Cubebenoate was isolated from an extract of Schisandra chinensis fruits. Antigen-induced degranulation and Ca(2+) mobilization were measured in RBL-2H3 mast cells. In addition, BALB/c mice were sensitized with ovalbumin and aluminum hydroxide, and then challenged with ovalbumin for three consecutive days. α-Cubebenoate (1mg/kg) was administered intraperitoneally 30min before each ovalbumin challenge. RESULTS In RBL-2H3 mast cells, α-cubebenoate inhibited antigen-induced degranulation and increase of intracellular Ca(2+) concentrations. In the ovalbumin-induced asthma model, α-cubebenoate suppressed bronchiolar structural changes induced by ovalbumin challenge. Furthermore, α-cubebenoate strongly inhibited accumulations of eosinophils, macrophages, and lymphocytes in bronchoalveolar lavage fluid. α-Cubebenoate also suppressed Th2 cytokines (IL-4 and IL-13) and TGF-β1 in lung tissues and in immune cells at the mRNA and protein levels. CONCLUSION α-Cubebenoate has an inhibitory effect on allergic inflammation and could be utilized as an agent for the treatment of asthma.

Petatewalide B, a novel compound from Petasites japonicus with anti-allergic activity

ETHNOPHARMACOLOGICAL RELEVANCE The giant butterbur Petasites japonicus is used to treat asthma and allergic diseases in traditional Korean, Japanese, and Chinese medicine. AIM OF THE STUDY To elucidate the anti-allergic effect of Petasites genus, we studied effects of several compounds from Petasites japonicus leaves and found a novel bakkenolide-type sesquiterpine. In the present study, anti-allergic and anti-inflammatory effects of the new compound was examined using in vivo and in vitro experiments. MATERIALS AND METHODS The novel compound was isolated from Petasites japonicus leaves and named petatewalide B. Antigen-induced degranulation and Ca(2+) mobilization were measured in RBL-2H3 mast cells by measuring β-hexosaminidase activity and fluorescence change of Ca(2+) probe, fura-2. Induction of inducible nitric oxide synthase and cyclooxygenase 2 was measured by Western blotting in peritoneal macrophages. In addition, ovalbumin-induced asthma model was used for in vivo efficacy test of petatewalide B. Membrane potential was estimated by measuring fluorescence change of DiBAC in C6 glioma cells. RESULTS Petatewalide B inhibited the antigen-induced degranulation of β-hexosaminidase in RBL-2H3 mast cells, but did not affect antigen-induced Ca(2+) increase in the cells. Petatewalide B also showed inhibition of the LPS-induced induction of iNOS, but not COX-2 in mouse peritoneal macrophages. Nitric oxide production was also inhibited by petatewalide B in macrophages. In the ovalbumin-induced asthma model, petatewalide B strongly inhibited accumulations of eosinophils, macrophages, and lymphocytes in bronchoalveolar lavage fluid. Petatewalide B increased the membrane potential of C6 glioma cells in a concentration-dependent manner. CONCLUSION Petatewalide B from Petasites genus not only has anti-allergic and anti-inflammatory effects but also induces a transient increase of membrane potential in C6 glioma cells.

Therapeutic Effects of S-Petasin on Disease Models of Asthma and Peritonitis

To explore the anti-allergic and anti-inflammatory effects of extracts of Petasites genus, we studied the effects of s-petasin, a major sesquiterpene from Petasites formosanus (a butterbur species) on asthma and peritonitis models. In an ovalbumin-induced mouse asthma model, s-petasin significantly inhibited the accumulations of eosinophils, macrophages, and lymphocytes in bronchoalveolar fluids. S-petasin inhibited the antigen-induced degranulation of β-hexosamidase but did not inhibit intracellular Ca2+ increase in RBL-2H3 mast cells. S-petasin inhibited the LPS induction of iNOS at the RNA and protein levels in mouse peritoneal macrophages. Furthermore, s-petasin inhibited the production of NO (the product of iNOS) in a concentration-dependent manner in the macrophages. Furthermore, in an LPS-induced mouse model of peritonitis, s-petasin significantly inhibited the accumulation of polymorpho nuclear and mononuclear leukocytes in peritoneal cavity. This study shows that s-petasin in Petasites genus has therapeutic effects on allergic and inflammatory diseases, such as, asthma and peritonitis through degranulation inhibition in mast cells, suppression of iNOS induction and production of NO in macrophages, and suppression of inflammatory cell accumulation.

Omega-3 fatty acids induce Ca2+ mobilization responses in human colon epithelial cell lines endogenously expressing FFA4

Aim:Free fatty acid receptor 4 (FFA4; formerly known as GPR120) is the G protein-coupled receptor (GPCR) for omega-3 polyunsaturated fatty acids. FFA4 has been found to express in the small intestines and colons of mice and humans. In this study we investigate the effects of omega-3 polyunsaturated fatty acids on FFA4 in human colon epithelial cells in vitro.Methods:HCT116 and HT-29 human colon epithelial cell lines endogenously expressing FFA4 were used. Intracellular Ca2+ concentration ([Ca2+]i) was measured in fura 2-AM-loaded cells with fluorescence spectrophotometry. RT-PCR and immunohistochemistry were used to detect FFA4.Results:Ten to 100 μmol/L of omega-3 polyunsaturated fatty acids α-linolenic acid (αLA) or eicosapentaenoic acid (EPA) induced dose-dependent [Ca2+]i increase in HCT116 and HT-29 cells, whereas docosahexaenoic acid (DHA) had no effect. In addition, the omega-6 fatty acids linoleic acid and γ-linoleic acid also dose-dependently increase [Ca2+]i, but the mono-unsaturated fatty acid oleic acid and saturated fatty acids such as stearic acid and palmitic acid had no effect. In HCT116 and HT-29 cells, the αLA-induced [Ca2+]i increase was partially inhibited by pretreatment with EGTA, phospholipase C inhibitor edelfosine, cADPR inhibitors 8-bro-cADPR or DAB, and abolished by pretreatment with Ca2+ATPase inhibitor thapsigargin, but was not affected by Gi/o protein inhibitor PTX or IP3R inhibitor 2-APB.Conclusion:Omega-3 and omega-6 long-chain polyunsaturated fatty acids (C18-20) induce Ca2+ mobilization responses in human colonic epithelial cells in vitro through activation of FFA4 and PTX-insensitive Gi/o protein, followed by Ca2+ release from thapsigargin-sensitive Ca2+ stores and Ca2+ influx across the plasma membrane.

Anti-Allergic Effect of Oroxylin A from Oroxylum indicum Using in vivo and in vitro Experiments

Oroxylum indicum has long been used in Asian traditional medicine to prevent and treat respiratory diseases, diabetes, diarrhea and other conditions. Oroxylin A is a flavone that is present in Oroxylum indicum and in Scutellaria baicalensis. Because the root extracts of both plants have been shown to have anti-allergic effects, the authors investigated whether oroxylin A is likely to have beneficial effects on allergic asthma using female Balb/c mice and rat RBL-2H3 mast cells. Antigen-induced degranulation was measured in vitro by measuring β-hexosaminidase activity. A murine ovalbumin-induced allergic asthma model was used to test the in vivo efficacy of oroxylin A. Sensitization and challenge of ovalbumin induced allergic asthma responses, the accumulations of eosinophils and Th2 cytokine levels in bronchoalveolar lavage fluid and lung tissues. Oroxylin A administration decreased numbers of inflammatory cells, especially eosinophils, and reduced the expression and secretion of Th2 cytokines, including IL-4 and IL-13, in lung tissues and bronchoalveolar lavage fluid. Histologic studies showed oroxylin A reduced inflammatory signs and mucin production in lungs. These findings provide evidence that oroxylin A has potential use as an anti-allergic therapeutic.

Ginsenoside Rg3 promotes inflammation resolution through M2 macrophage polarization

Background Ginsenosides have been reported to have many health benefits, including anti-inflammatory effects, and the resolution of inflammation is now considered to be an active process driven by M2-type macrophages. In order to determine whether ginsenosides modulate macrophage phenotypes to reduce inflammation, 11 ginsenosides were studied with respect to macrophage polarization and the resolution of inflammation. Methods Mouse peritoneal macrophages were polarized into M1 or M2 phenotypes. Reverse transcription-polymerase chain reaction, Western blotting, and measurement of nitric oxide (NO) and prostaglandin E2 levels were performed in vitro and in a zymosan-induced peritonitis C57BL/6 mouse model. Results Ginsenoside Rg3 was identified as a proresolving ginseng compound based on the induction of M2 macrophage polarization. Ginsenoside Rg3 not only induced the expression of arginase-1 (a representative M2 marker gene), but also suppressed M1 marker genes, such as inducible NO synthase, and NO levels. The proresolving activity of ginsenoside Rg3 was also observed in vivo in a zymosan-induced peritonitis model. Ginsenoside Rg3 accelerated the resolution process when administered at peak inflammatory response into the peritoneal cavity. Conclusion These results suggest that ginsenoside Rg3 induces the M2 polarization of macrophages and accelerates the resolution of inflammation. This finding opens a new avenue in ginseng pharmacology.