Phil-Dong Moon

Thymic stromal lymphopoietin is expressed and produced by caspase-1/NF-κB pathway in mast cells

Thymic stromal lymphopoietin (TSLP) plays a pivotal role in allergic diseases such as atopic dermatitis, asthma, and chronic obstructive pulmonary disease. Although there are many reports regarding function and regulatory mechanism of TSLP in dendritic cells and/or T cells, the regulatory mechanism of TSLP in mast cells has not been fully elucidated. Here, we describe how TSLP is expressed and produced by inflammatory stimulus in mast cells. TSLP mRNA was expressed by phorbol myristate acetate (PMA) plus A23187 stimulation in HMC-1 cells and reached its peak 5h after PMA plus A23187 stimulation. The expression of TSLP mRNA was inhibited by nuclear factor (NF)-κB inhibitor. In addition, NF-κB luciferase activity was inhibited by caspase-1 inhibitor, indicating that caspase-1 is an upstream of NF-κB in mast cells. Furthermore, caspase-1 inhibitor decreased the expression of TSLP mRNA induced by PMA plus A23187. Finally, TSLP production was inhibited by both caspase-1 inhibitor and NF-κB inhibitor. These results provide proof of principle that TSLP can be expressed and produced through caspase-1 and NF-κB in mast cells and open new perspectives to pharmacologically manipulate the expression and production of TSLP by molecules acting on the caspase-1 and NF-κB pathway.

TSLP induces mast cell development and aggravates allergic reactions through the activation of MDM2 and STAT6.

Thymic stromal lymphopoietin (TSLP) is known to promote T helper type 2 cell-associated inflammation. Mast cells are major effector cells in allergic inflammatory responses. We noted that the population and maturation of mast cells were reduced in TSLP-deficient mice (TSLP-/-). Thus, we hypothesized that TSLP might affect mast cell development. We found that TSLP induced the proliferation and differentiation of mast cells from bone marrow progenitors. TSLP-induced mast cell proliferation was abolished by depletion of mouse double minute 2 (MDM2) and signal transducers and activators of transcription 6 (STAT6), as an upstream activator of MDM2. TSLP-/-, in particular, had a considerable deficit in the expression of MDM2 and STAT6. Also, the TSLP deficiency attenuated mast cell-mediated allergic reactions through the downregulation of STAT6 and MDM2. In an antibody microarray chip analysis, MDM2 expression was increased in atopic dermatitis patients. These observations indicate that TSLP is a factor for mast cell development, and that it aggravates mast cell-mediated immune responses.

Activation of hypoxia-inducible factor-1 regulates human histidine decarboxylase expression

Abstract.Histidine decarboxylase (HDC) catalyzes the formation of histamine from histidine. Histamine has various effects in physiological and pathological reactions, such as inflammation, cell growth, and neuro-transmission. We investigated the role of hypoxia-inducible factor (HIF)-1 on hypoxia-induced HDC expression in human mast cell line, HMC-1 cells and mouse bone marrow-derived mast cells (BMMCs). Hypoxia significantly increased histamine production. HDC expression and activity were induced by hypoxia. Additionally, when cells were transfected with a native form of HIF-1α, hypoxia could induce higher HDC expression than in the nontransfected cell. HIF-1 binding activity for HDC 5’ flanking region (HFR) was similar to that for the hypoxia-responsive element. Using HDC promoter deletion analysis, we also demonstrated that HFR was regulated by HIF-1 activation. In addition, depletion of HIF-1α prevents hypoxic induction of HDC in BMMCs. In conclusion, these results demonstrate that hypoxia induces HDC expression by transcriptional mechanisms dependent upon HIF-1.

Use of Electroacupuncture at ST36 to Inhibit Anaphylactic and Inflammatory Reaction in Mice

Objective: Electroacupuncture (EA) has been used to treat myalgia, allergy and gastroenteropathy in Korea. To determine whether EA can treat anaphylactic and inflammatory reactions, the effect of EA was investigated in a murine model. Methods: EA stimulation of the ST36 acupoint was performed for 10 min. Using a passive cutaneous anaphylaxis (PCA) model, the antianaphylactic effects of EA were examined. Interleukin-6 and tumor necrosis factor-α were measured using the ELISA method. The level of nuclear factor (NF)-ĸB/RelA protein and NF-ĸB DNA-binding activity was determined using the Western blot analysis and the transcription factor enzyme-linked immunoassay method. Results: EA inhibits PCA and β-hexosaminidase release, IL-6 secretion on the PCA, and in addition, EA reduces NF-ĸB DNA-binding activity. Conclusion: These results indicate that EA may possess antianaphylactic and antiinflammatory properties.

Naringenin suppresses the production of thymic stromal lymphopoietin through the blockade of RIP2 and caspase-1 signal cascade in mast cells

Thymic stromal lymphopoietin (TSLP) plays a critical role in allergic diseases such as atopic dermatitis, asthma, and chronic obstructive pulmonary disease. Naringenin has various effects such as anti-atherogenic, anti-oxidant, and anti-inflammatory effects. However, the effect of naringenin on the production of TSLP has not been clarified. Thus, we investigated how naringenin inhibits the production of TSLP in the human mast cell line (HMC-1) cells. Naringenin inhibited the production and mRNA expression of TSLP in HMC-1 cells. The maximal inhibition rate of TSLP production by naringenin (100 μM) was 62.27 ± 10.79%. Naringenin also inhibited the nuclear factor-κB luciferase activity induced by phorbol myristate acetate plus A23187. In the activated HMC-1 cells, the activations of receptor-interacting protein (RIP)2 and caspase-1 were increased, whereas the activations of RIP2 and caspase-1 were decreased by pretreatment with naringenin. These results suggest that naringenin can be used to treat inflammatory and atopic diseases through the inhibition of TSLP.

Mountain Grown Ginseng Induces Apoptosis in HL-60 Cells and Its Mechanism Have Little Relation with TNF-α Production

The root of ginseng is one of the most popular natural tonics in Oriental countries. Ginseng grown in the wild, deep in the mountains, is known as Sansam (mountain grown ginseng, MGG). MGG belongs to Araliaceae and Panax. In this study, we investigated the effects of MGG on the cytotoxicity, induction of apoptosis and the putative pathways of its actions in human promyelocytic leukemia cells, HL-60. Using apoptosis analysis, we found that MGG is a potent inducer of apoptosis, but it has less effect on human peripheral blood mononuclear cells. Caspase-3 activation and subsequent apoptotic cell death in MGG-treated cells were partially blocked by the caspase-3 inhibitor, Z-DEVD-FMK. MGG also inhibited the caspase-8 activity. To determine whether MGG-induced apoptosis is involved in tumor necrosis factor-alpha (TNF-alpha) secretion, TNF-alpha secretion was quantified by enzyme-linked immunosorbent assay (ELISA) method. Unexpectedly, MGG significantly decreased the TNF-alpha secretion compared to the control. These results suggest that MGG-induced cytotoxicity have little relation with the secretion of TNF-alpha in HL-60 cells. Furthermore, MGG with rIFN-gamma synergistically increased nitric oxide (NO) production in mouse peritoneal macrophages. Taken together, our data indicate that MGG is a potent inducer of apoptosis on HL-60 cells and these abilities could be used clinically for the treatment of cancer.

Lithospermi radix Extract Inhibits Histamine Release and Production of Inflammatory Cytokine in Mast Cells

Lithospermi radix (LR, Borraginaceae, the root of Lithospermum erythrorhizon Siebold. et Zuccarinii) is used in herbal medicine to treat such conditions as eczema, skin burns and frostbite. This study investigates the effects of LR on the anti-allergy mechanism. LR inhibited the release of histamine from rat peritoneal mast cells by compound 48/80 in a dose-dependent manner. LR orally administered at 6.59 mg/100 g also inhibited the anti-DNP IgE-induced passive cutaneous anaphylaxis reaction. LR inhibited the PMA plus A23187-induced increase in IL-6, IL-8, and TNF-α expression in HMC-1 cells. In addition, LR also inhibited nuclear factor-kappa B (NF-κB) activation and IκB-α degradation. These results show that LR had an inhibitory effect on the atopic allergic reaction. Furthermore, the in vivo and in vitro anti-allergic effect of LR suggests possible therapeutic applications of this agent for inflammatory allergic diseases.

The critical role of mast cell-derived hypoxia-inducible factor-1α in human and mice melanoma growth

Mast cells play an important role in tumorigenesis. Histamine released from mast cells stimulates new vessel formation by acting through the histamine1 (H1) receptor. Despite the evidence of the role of mast cells in tumor growth and angiogenesis, the potential mechanism remains to be elucidated. Therefore, we investigated the role of mast cell‐derived HIF‐1α in melanoma growth. Here, we identify that the most positive cells for HIF‐1α staining are seen in mast cells of human and animal melanoma tissue. The number of the stromal cell types (fibroblasts, macrophages and endothelial cells) was also increased in melanoma tissues. In activated bone marrow‐derived mast cells (BMMCs), expressions of HIF‐1α and VEGF were increased. Histamine also induced the expressions of HIF‐1α and VEGF in BMMCs. H1 receptor antagonists significantly improved overall survival rates and substantially suppressed tumor growth as well as the infiltration of mast cells and levels of VEGF through the inhibition of HIF‐1α expression in B16F10 melanoma‐bearing mice. Furthermore, the injection of HIF‐1α depleted BMMCs markedly inhibited the growth of tumors and migration of mast cells and increased the survival rate of the mice. These findings emphasize that the growth of melanoma can actually be exacerbated by mast cell‐derived HIF‐1α. In aggregate, our results reveal a novel role for mast cell‐derived HIF‐1α in the melanoma microenvironment and have important implications for the design of therapeutic strategies.

Interleukin-32-induced thymic stromal lymphopoietin plays a critical role in macrophage differentiation through the activation of caspase-1 in vitro.

IntroductionInterleukin (IL)-32 is an inflammatory cytokine induced by Mycobacterium tuberculosis and Mycobacterium bovis in a variety of cell types and discovered in the synovial of patients with rheumatoid arthritis (RA). Thymic stromal lymphopoietin (TSLP) play several roles in the pathogenesis of RA. However, the role of IL-32 and TSLP in RA has not been elucidated.MethodsWe evaluated the specific mechanism of between IL-32 and TSLP in RA using human monocyte cell line, THP-1 cells.ResultsHere we documented for the first time that IL-32 highly increased TSLP production in THP-1 cells and human blood monocytes. TSLP expression was induced by IL-32 via activation of caspase-1 and nuclear factor-κB. TSLP produced by IL-32 increased differentiation of monocytes but depletion of TSLP prevented differentiation of monocytes into macrophage-like cells. Chondroprotective drugs such as chondroitin sulfate (CS) and the traditional Korean medicine, BaekJeol-Tang (BT) decrease production of TSLP and activation of caspase-1 and nuclear factor-κB. In addition, CS and BT inhibited IL-32-induced monocytes differentiation.ConclusionsTaken together, IL-32 and TSLP are important cytokines involved in the development of RA. The effects of CS and BT were associated with the downregulation of TSLP and caspase-1 through negative regulation of IL-32 pathways in RA.

Anti-Inflammatory Activity of Schizonepeta tenuifolia through the Inhibition of MAPK Phosphorylation in Mouse Peritoneal Macrophages

Schizonepeta tenuifolia (ST) is a well-known herb to treat the cold and its associated headache. However, the anti-inflammatory mechanism of ST in mouse peritoneal macrophages is not clear. In this study, we demonstrated that ST inhibited lipopolysaccaride (LPS)-induced tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 production. The maximal inhibition rate of TNF-alpha and IL-6 production by ST (2 mg/ml) was 48.01 +/- 2.8% and 56.45 +/- 2.8%, respectively. During the inflammatory process, cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) were increased in mouse peritoneal macrophages. However, treated with ST decreased the protein level of COX-2 and iNOS, as well as the production of PGE(2) and NO in LPS-stimulated mouse peritoneal macrophages. In addition, ST inhibited the phosphorylation of MAPK. Taken together, the results of this study suggest an important molecular mechanism by which ST reduces inflammation, which may explain its beneficial effect in the regulation of inflammatory reactions.