the control group; *vs. quantity of mast cells, production levels of cytokines and migration of dendritic cells. Our findings provide evidence that this anti-allergic inflammatory properties of roxatidine are mediated by the inhibition of NF-B and caspase-1 activation, p38 MAPK pathway and mast cell-derived cytokine production. Taken together, the and anti-allergic inflammatory effects suggest a possible therapeutic application of roxatidine in allergic inflammatory diseases. Allergic disorders, such as anaphylaxis, hay fever, eczema and asthma, now afflict roughly 25% of people in the developed world. In allergic subjects, prolonged or repetitive exposure to allergens, which typically are intrinsically innocuous substances common in the environment, results in chronic allergic inflammation1. Mast cells are central effector cells that cause immediate hypersensitivity and play multiple immunological functions in many inflammatory responses2. Immediate hypersensitivity is usually mediated by histamine release in response to the antigen cross-linking of immunoglobulin E (IgE) bound to high affinity surface receptors for IgE (FcRI) on mast cells. Mast cells are activated by the process of degranulation, which triggers the release of mediators such as histamine by calcium signaling. The degranulation of mast cells can also be induced by the synthetic compound 48/80, phorbol 12-myristate 13-acetate (PMA), and calcium ionophore. Compound 48/80 has been used as a direct and convenient reagent to examine the mechanism underlying allergic reactions3. NF-B refers to a class of transcription factors involved in immune regulation, apoptosis, differentiation, inflammation, and malignancy4. NF-B is usually sequestered in the cytoplasm as an inactive complex bound by an inhibitor, known as IB5. In response to a variety of signaling events, the IB kinase complex (IKK) phosphorylates IB proteins. This post-translational modification targets IB for poly-ubiquitination and subsequent degradation by the 26?S proteasome6,7. The degradation of IB proteins liberates NF-B, allowing this transcription factor to translocate to the nucleus and activate its target genes. Besides regulation by IB, NF-B-dependent gene expression is also negatively regulated by the zinc finger protein A20, even though molecular mechanism remains unclear8. It has been reported that this activation of NF-B is usually brought on by mitogen-activated protein kinases (MAPKs) such as extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), and p38 MAPK9. However, other reports showed a negative regulation between NF-B and MAPKs10. Therefore, the relationship between NF-B and MAPKs is usually complex and appears to depend around the cell type and stimulus. Roxatidine acetate hydrochloride (2-acetoxy-N-[3-[m-(1-piperidinylmethyl) phenoxy] propyl] acetamide hydrochloride) is usually a histamine H2-receptor antagonist that is used to treat gastric and duodenal ulcers11. This compound is usually rapidly converted to its active metabolite, roxatidine, by esterases in the small intestine, plasma, and liver. Thus, it cannot be found in plasma samples taken from volunteers after oral administration12. Roxatidine is used clinically as an anti-ulcer agent. This drug is also known to increase gastric mucus, inhibit gastric acid secretion, and ameliorate gastric mucosal injury caused by diclofenac or aspirin13,14. In particular, roxatidine has also been reported to suppress histamine release (thus inhibiting proton secretion) and inhibit the production of VEGF-1, an important marker of inflammation and angiogenesis15. In addition, we reported the anti-inflammatory activities of roxatidine including inhibition of NF-kB and p38 MAPK activation in LPS-induced RAW 264.7 macrophages16. Although roxatidine has been reported to show numerous bioactivities, the anti-allergic inflammatory effect of roxatidine remains unclear. Therefore, to evaluate the potential anti-allergic activity of compounds, we investigated the molecular mechanisms involved in the.3C). evidence that the anti-allergic inflammatory properties of RAF1 roxatidine are mediated by the inhibition of NF-B and caspase-1 activation, p38 MAPK pathway and mast cell-derived cytokine production. Taken together, the and anti-allergic inflammatory effects suggest a possible therapeutic application of roxatidine in allergic inflammatory diseases. Allergic disorders, such as anaphylaxis, hay fever, eczema and asthma, now afflict roughly 25% of people in the developed world. In allergic subjects, persistent or repetitive exposure to allergens, which typically are intrinsically innocuous substances common in the environment, results in chronic allergic inflammation1. Mast cells are central effector cells that cause immediate hypersensitivity and play multiple immunological roles in many inflammatory responses2. Immediate hypersensitivity is mediated by histamine release in response to the antigen cross-linking of immunoglobulin E (IgE) bound to high affinity surface receptors for IgE (FcRI) on mast cells. Mast cells are activated by the process of degranulation, which triggers the release of mediators such as histamine by calcium signaling. The degranulation of mast cells can also be induced by the synthetic compound 48/80, phorbol 12-myristate 13-acetate (PMA), and calcium ionophore. Compound 48/80 has been used as a direct and convenient reagent to examine the mechanism underlying allergic reactions3. NF-B refers to a class of transcription factors involved in immune regulation, apoptosis, differentiation, inflammation, and cancer4. NF-B is sequestered in the cytoplasm as an inactive complex bound by an inhibitor, known as IB5. In response to a variety of signaling events, the IB kinase complex (IKK) phosphorylates IB proteins. This post-translational modification targets IB for poly-ubiquitination and subsequent degradation by the 26?S proteasome6,7. The degradation of IB proteins liberates NF-B, allowing this transcription factor to translocate to the nucleus and activate its target genes. Besides regulation by IB, NF-B-dependent gene expression is also negatively regulated by the zinc finger protein A20, although the molecular mechanism remains unclear8. It has been reported that the activation of NF-B is triggered by mitogen-activated protein kinases Azoxymethane (MAPKs) such as extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), and p38 MAPK9. However, other reports showed a negative regulation between NF-B and MAPKs10. Therefore, the relationship between NF-B and MAPKs is complex and appears to depend on the cell type and stimulus. Roxatidine acetate hydrochloride (2-acetoxy-N-[3-[m-(1-piperidinylmethyl) phenoxy] propyl] acetamide hydrochloride) is a histamine H2-receptor antagonist that is used to treat gastric and duodenal ulcers11. This compound is rapidly converted to its active metabolite, roxatidine, by esterases in the small intestine, plasma, and liver. Thus, it cannot be found in plasma samples taken from volunteers after oral administration12. Roxatidine is used clinically as an anti-ulcer agent. This drug is also known to increase gastric mucus, inhibit gastric acid secretion, and ameliorate gastric mucosal injury caused by diclofenac or aspirin13,14. In particular, roxatidine has also been reported to suppress histamine release (thus inhibiting proton secretion) and inhibit the production of VEGF-1, an important marker of inflammation and angiogenesis15. In addition, we reported the anti-inflammatory activities of roxatidine including inhibition of NF-kB and p38 MAPK activation in LPS-induced RAW 264.7 macrophages16. Although roxatidine has been reported to show various bioactivities, the anti-allergic inflammatory effect of roxatidine remains unclear. Therefore, to evaluate the potential anti-allergic activity of compounds, we investigated the molecular mechanisms involved in the anti-allergic inflammatory properties of roxatidine in an activated human mast cells and in a murine model of anaphylactic shock and contact hypersensitivity (CHS). Results Roxatidine suppressed the PMACI-induced production of pro-inflammatory cytokines in HMC-1 To determine the inhibitory effects of roxatidine in pro-inflammatory cytokine production induced by PMACI, we investigated its effects on PMACI-induced TNF-, IL-6, and IL-1 production (Fig. 1B) and their mRNA levels (Fig. 1C), by using EIA and qRT-PCR, respectively. Pretreatment with roxatidine down-regulated the PMACI-induced TNF-, IL-6, and IL-1 production and their mRNA expression in a dose-dependent manner. These data indicated that roxatidine regulated the PMACI-induced expression of TNF-, IL-6, and IL-1 through transcriptional.and H.J.A. 48/80-induced anaphylactic mice. In CHS model, roxatidine significantly reduced ear swelling, increased number of mast cells, production levels of cytokines and migration of dendritic cells. Our findings provide evidence that the anti-allergic inflammatory properties of roxatidine are mediated by the inhibition of NF-B and caspase-1 activation, p38 MAPK pathway and mast cell-derived cytokine production. Taken together, the and anti-allergic inflammatory effects suggest Azoxymethane a possible therapeutic application of roxatidine in allergic inflammatory diseases. Allergic disorders, such as anaphylaxis, hay fever, eczema and asthma, now afflict roughly 25% of people in the developed world. In allergic subjects, persistent or repetitive exposure to allergens, which typically are intrinsically innocuous substances common in the environment, results in chronic allergic inflammation1. Mast cells are central effector cells that cause immediate hypersensitivity and play multiple immunological roles in many inflammatory responses2. Immediate hypersensitivity is mediated by histamine release in response to the antigen cross-linking of immunoglobulin E (IgE) bound to high Azoxymethane affinity surface receptors for IgE (FcRI) on mast cells. Mast cells are activated by the process of degranulation, which triggers the release of Azoxymethane mediators such as histamine by calcium signaling. The degranulation of mast cells can also be induced by the synthetic compound 48/80, phorbol 12-myristate 13-acetate (PMA), and calcium ionophore. Compound 48/80 has been used as a direct and convenient reagent to examine the mechanism underlying allergic reactions3. NF-B refers to a class of transcription factors involved in immune regulation, apoptosis, differentiation, inflammation, and cancer4. NF-B is sequestered in the cytoplasm as an inactive complex bound by an inhibitor, known as IB5. In response to a variety of signaling events, the IB kinase complex (IKK) phosphorylates IB proteins. This post-translational modification targets IB for poly-ubiquitination and subsequent degradation by the 26?S proteasome6,7. The degradation of IB proteins liberates NF-B, allowing this transcription factor to translocate to the nucleus and activate its target genes. Besides regulation by IB, NF-B-dependent gene expression is also negatively regulated by the zinc finger protein A20, although the molecular mechanism remains unclear8. It has been reported that the activation of NF-B is triggered by mitogen-activated protein kinases (MAPKs) such as extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), and p38 MAPK9. However, other reports showed a negative regulation between NF-B and MAPKs10. Therefore, the relationship between NF-B and MAPKs is complex and appears to depend on the cell type and stimulus. Roxatidine acetate hydrochloride (2-acetoxy-N-[3-[m-(1-piperidinylmethyl) phenoxy] propyl] acetamide hydrochloride) is a histamine H2-receptor antagonist that is used to treat gastric and duodenal ulcers11. This compound is rapidly converted to its active metabolite, roxatidine, by esterases in the small intestine, plasma, and liver. Thus, it cannot be found in plasma samples taken from volunteers after oral administration12. Roxatidine is used clinically as an anti-ulcer agent. This drug is also known to increase gastric mucus, inhibit gastric acid secretion, and ameliorate gastric mucosal injury caused by diclofenac or aspirin13,14. In particular, roxatidine has also been reported to suppress histamine release (thus inhibiting proton secretion) and inhibit the production of VEGF-1, an important marker of inflammation and angiogenesis15. In addition, we reported the anti-inflammatory activities of roxatidine including inhibition of NF-kB and p38 MAPK activation in LPS-induced RAW 264.7 macrophages16. Although roxatidine has been reported to show various bioactivities, the anti-allergic inflammatory effect of roxatidine remains unclear. Therefore, to evaluate the potential anti-allergic activity of compounds, we investigated the molecular mechanisms involved in the anti-allergic inflammatory properties of roxatidine in an activated human mast cells and in a murine model of anaphylactic surprise and get in touch with hypersensitivity (CHS). Outcomes Roxatidine suppressed the PMACI-induced creation of pro-inflammatory cytokines in HMC-1 To look for the inhibitory ramifications of roxatidine in pro-inflammatory cytokine.