Epigallocatechin-3-O-gallate inhibits the production of thymic stromal lymphopoietin by the blockade of caspase-1/NF-κB pathway in mast cells

Chloroquine attenuates thymic stromal lymphopoietin production via suppressing caspase-1 signaling in mast cells

Thymic stromal lymphopoietin (TSLP) produced by mast cells is involved in allergic inflammation pathogenesis. Chloroquine (CQ) is known to be an anti-malarial drug; however, additional protective functions of CQ have been discovered. This study aims to clarify an anti-inflammatory effect of CQ through modulating TSLP levels using an in vitro model of phorbol myristate acetate (PMA) + A23187-activated human mast cell line (HMC-1) and an in vivo model of PMA-irritated ear edema. CQ treatment reduced the production and mRNA expression levels of TSLP in activated HMC-1 cells. CQ down-regulated caspase-1 (CASP1), MAPKs, and NF-κB levels enhanced by stimulation with PMA + A23187. Moreover, ear thickness in ear edema was suppressed following CQ treatment. CQ decreased CASP1 and NF-κB levels in the ear tissue. TSLP levels in the ear tissue and serum were reduced following CQ treatment. Collectively, the above findings elucidate that CQ inhibits the pro-inflammatory mechanisms of TSLP via the down-regulation of distinct intracellular signaling cascade in mast cells. Therefore, CQ may have protective roles against TSLP-mediated inflammatory disorders.

Use of Physcion to Improve Atopic Dermatitis-Like Skin Lesions through Blocking of Thymic Stromal Lymphopoietin

Physcion is well known for the treatment of carcinoma. However, the therapeutic effect of physcion on atopic dermatitis (AD) through the inhibition of thymic stromal lymphopoietin (TSLP) level remains largely unknown. In this study, we investigated the anti-AD effect of physcion using HMC-1 cells, splenocytes, and a murine model. Treatment with physcion decreased production and mRNA expression levels of TSLP, IL-6, TNF-ɑ, and IL-1β in activated HMC-1 cells. Physcion reduced the expression levels of RIP2/caspase-1 and phospho (p)ERK/pJNK/pp38 in activated HMC-1 cells. Physcion suppressed the expression levels of pIKKβ/NF-κB/pIkB in activated HMC-1 cells. Moreover, physcion attenuated the production levels of TSLP, IL-4, IL-6, TNF-, and IFN-γ from activated splenocytes. Oral administration of physcion improved the severity of 2,4-dinitrochlorobenzene-induced AD-like lesional skin through reducing infiltration of inflammatory cells and mast cells, and the protein and mRNA levels of TSLP, IL-4, and IL-6 in the lesional skin tissues. Physcion attenuated histamine, IgE, TSLP, IL-4, IL-6, and TNF- levels in serum. In addition, physcion inhibited caspase-1 activation in the lesional skin tissues. These findings indicate that physcion could ameliorate AD-like skin lesions by inhibiting TSLP levels via caspase-1/MAPKs/NF-kB signalings, which would provide experimental evidence of the therapeutic potential of physcion for AD.

Effects of Linalyl Acetate on Thymic Stromal Lymphopoietin Production in Mast Cells

Thymic stromal lymphopoietin (TSLP) is an important factor responsible for the pathogenesis of allergic diseases, such as atopic dermatitis and asthma. Because linalyl acetate (LA) possesses a wide range of pharmacological properties, being antispasmodic, anti-inflammatory, and anti-hyperpigmentation, we hypothesized that LA could inhibit TSLP. Therefore, enzyme-linked immunosorbent assay, quantitative polymerase chain reaction, caspase-1 assay, Western blot analysis, fluorescent analyses of the intracellular calcium levels, and the phorbol myristate acetate (PMA)-induced edema model were used to investigate how LA inhibits the production of TSLP in HMC-1 cells. LA reduced the production and mRNA expression of TSLP in HMC-1 cells. LA also inhibited the activation of nuclear factor-κB and degradation of IκBα. PMA plus A23187 stimulation up-regulated caspase-1 activity in HMC-1 cells; however, this up-regulated caspase-1 activity was down-regulated by LA. Finally, LA decreased intracellular calcium levels in HMC-1 cells as well as PMA-induced ear swelling responses in mice. Taken together, these results suggest that LA would be beneficial to treatment of atopic and inflammatory diseases by reducing TSLP.

Against NF-κB/thymic stromal lymphopoietin signaling pathway, catechin alleviates the inflammation in allergic rhinitis

BACKGROUND

The prevalence of allergic rhinitis has risen sharply. Previous work has demonstrated the anti-inflammatory effect of catechin, including in models of allergic disease. However, the molecular mechanisms underlying this therapeutic effect remain unclear. Thymic stromal lymphopoietin(TSLP), as a molecule from epithelial cell, has been identified that plays a significant role in the development of allergic disease, and the production of TSLP is related to activation of the NF-κB signaling pathway. For that, we try to research the treatment of catechin for allergic rhinitis and found out possible mechanism under this effect, which was based on TSLP factor.

MATERIALS AND METHODS

Here, the anti-inflammatory effects of catechin were studied in an ovalbumin-induced allergic rhinitis murine model and a vitro experiments using poly(I:C)-stimulated human nasal epithelial cells(HNEpCs). The pharmacological effects of catechin in allergic rhinitis mice were assessed by observing the allergic symptoms, performing hematoxylin and eosin staining and Giemsa staining of the nasal tissues. Additionally, the TSLP expression in epithelial cells was tested by enzyme-linked immunosorbent assays, immunohistochemistry, and western blots. The serum levels of interleukin-5, interleukin-13, and ovalbumin-specific immunoglobulin-E were detected by enzyme-linked immunosorbent assays, and the balance between T helper type 1 and T helper type 2 cells was assessed by flow cytometry. The expression levels of phospho-NF-κBp65, IκBα, and NF-κBp65 proteins were further investigated by western blots or immunofluorescence.

RESULTS

Our results reveal that catechin, in doses of 75, 150, or 300 mg/kg, remitted the allergic symptoms in mice with allergic rhinitis, like sneezing and nasal rubbing. Catechin could reduce the levels of interleukin-5, interleukin-13, and ovalbumin-specific immunoglobulin-E in the serum and restored the T helper type 2/T helper type 1 cell balance and also had anti-thymic stromal lymphopoietin effects. Moreover, as an upstream regulator of TSLP, the NF-κB signal pathway was also suppressed after catechin treatment, which was demonstrated by the observed decrease in phospho-NF-κBp65 and NF-κBp65 levels and the reduction of IκBα degradation and NF-κBp65 nuclear translocation.

CONCLUSIONS

Catechin effectively reduced the inflammation in allergic rhinitis. The underlying mechanism is that catechin inhibited the expression of TSLP in epithelial cells by influencing NF-κB/TSLP pathway.

Cysteine induces longitudinal bone growth in mice by upregulating IGF-I

Cysteine (Cys) is known to exert various effects, such as antioxidant, antipancreatitic and antidiabetic effects. However, the effects of Cys on longitudinal bone growth have not been elucidate to date. Thus, the aim of the present study was to evaluate the effects of Cys on bone growth. Growth-plate thickness and bone parameters, such as bone volume/tissue volume (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), connectivity density (Conn.D) and total porosity were analyzed by means of micro-computed tomography (μCT). The levels of serum insulin-like growth factor-I (IGF-I) were measured by enzyme-linked immunosorbent assay (ELISA). Hepatic IGF-I mRNA expression was analyzed by quantitative polymerase chain reaction (qPCR). The phosphorylation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 5 (STAT5) was investigated by western blot analysis. Our results revealed that Cys increased IGF-I mRNA expression in HepG2 cells. The thickness of the growth plates was increased following treatment with Cys. Moreover, BV/TV, Tb.Th, TbN, Conn.D and total porosity were improved following treatment with Cys. Hepatic IGF-I mRNA expression and serum IGF-I levels were increased by Cys. The levels of phosphorylated JAK2 and STAT5 were elevated by Cys. The findings of our study indicate that Cys increases the thickness of growth plates through the upregulation of IGF-I, which results from the phosphorylation of JAK2-STAT5. Thus, our data suggest that Cys may have potential for use as a growth-promoting agent.

Taurine, a major amino acid of oyster, enhances linear bone growth in a mouse model of protein malnutrition

Oysters (Oys) contain various beneficial components, such as, antioxidants and amino acids. However, the effects of Oys or taurine (Tau), a major amino acid in Oys on bone growth have not been determined. In the present study, we evaluated the effects of Oys or Tau on linear bone growth in a mouse model of protein malnutrition. To make the protein malnutrition in a mouse, we used a low protein diet. Growth plate thickness was increased by Oys or Tau. Bone volume/tissue volume, trabecular thickness, trabecular number, connection density, and total porosity were also improved by Oys or Tau. Oys or Tau increased insulin-like growth factor-1 (IGF-1) levels in serum, liver, and tibia-growth plate. Phosphorylations of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 5 (STAT5) were increased by Oys and by Tau. These findings show that Oys or Tau may increase growth plate thickness by elevating IGF-1 levels and by promoting the phosphorylations of JAK2-STAT5, and suggest that Oys or Tau are growth-promoting substances of potential use in the food and pharmaceutical industries.

Cytokine inhibition in the treatment of COPD

Cytokines play an important part in many pathobiological processes of chronic obstructive pulmonary disease (COPD), including the chronic inflammatory process, emphysema, and altered innate immune response. Proinflammatory cytokines of potential importance include tumor necrosis factor (TNF)-α, interferon-γ, interleukin (IL)-1β, IL-6, IL-17, IL-18, IL-32, and thymic stromal lymphopoietin (TSLP), and growth factors such as transforming growth factor-β. The current objectives of COPD treatment are to reduce symptoms, and to prevent and reduce the number of exacerbations. While current treatments achieve these goals to a certain extent, preventing the decline in lung function is not currently achievable. In addition, reversal of corticosteroid insensitivity and control of the fibrotic process while reducing the emphysematous process could also be controlled by specific cytokines. The abnormal pathobiological process of COPD may contribute to these fundamental characteristics of COPD, and therefore targeting cytokines involved may be a fruitful endeavor. Although there has been much work that has implicated various cytokines as potentially playing an important role in COPD, there have been very few studies that have examined the effect of specific cytokine blockade in COPD. The two largest studies that have been reported in the literature involve the use of blocking antibody to TNFα and CXCL8 (IL-8), and neither has provided benefit. Blocking the actions of CXCL8 through its CXCR2 receptor blockade was not successful either. Studies of antibodies against IL-17, IL-18, IL-1β, and TSLP are currently either being undertaken or planned. There is a need to carefully phenotype COPD and discover good biomarkers of drug efficacy for each specific target. Specific groups of COPD patients should be targeted with specific anticytokine therapy if there is evidence of high expression of that cytokine and there are features of the clinical expression of COPD that will respond.

The expanding role of IL-7 and thymic stromal lymphopoietin as therapeutic target for rheumatoid arthritis

INTRODUCTION

The discovery of IL-7 and thymic stromal lymphopoietin (TSLP) has been a major step in the understanding of arthritis. IL-7 amplifies the inflammation induced by other cytokines, primarily TNF. In animal models of arthritis, inhibition of IL-7 limits inflammation and joint erosion. TSLP is an IL-7-like cytokine that triggers dendritic cell-mediated Th2-type inflammatory responses and is considered as a master switch for allergic inflammation. TSLP is a downstream molecule of TNF-α and as such may be involved in the pathophysiology of inflammatory arthritis.

AREAS COVERED

This review summarizes current knowledge of the role of IL-7 and TSLP derived from both animal models and studies in patients with rheumatoid arthritis (RA). The emergence of IL-7 blockade as a future therapy in RA is highlighted, along with the potential goals and limitations of this therapeutic approach. The write-up also highlights the functional capacities of TSLP in arthritis.

EXPERT OPINION

Evidences suggest important roles for IL-7 and TSLP in the pathogenesis of RA and can be viewed as potential therapeutic targets. Regulation of these at genetic level is a promising investigational area. Given the difficulty in reconstituting T cells in patients with RA, therapeutic approaches that minimize the elimination of T cells are likely to be more desirable.

Down-regulation of thymic stromal lymphopoietin by curcumin

BACKGROUND

Thymic stromal lymphopoietin (TSLP) is a cytokine implicated in the pathogenesis of allergic diseases such as asthma, atopic dermatitis and allergic rhinitis. Curcumin has various effects such as antidepressant, antioxidant, antihyperglycemic, antitumor and anti-inflammatory. However, the effect of curcumin on the production of TSLP has not been clarified. Thus, we investigated how curcumin inhibits the expression and production of TSLP in the human mast cell line, HMC-1 cells.

METHODS

We used enzyme-linked immunosorbent assay, reverse transcription-polymerase chain reaction, luciferase assay, and caspase-1 assay to investigate the effects of curcumin.

RESULTS

The results show that curcumin inhibited the production and mRNA expression of TSLP in HMC-1 cells: the maximal inhibition rate of TSLP production by curcumin (50 μM) was 59.16 ± 4.20%. In addition, curcumin suppressed the nuclear factor-κB luciferase activity induced by phorbol myristate acetate plus A23187. In the activated HMC-1 cells, caspase-1 activity was increased, whereas caspase-1 activity was decreased by pretreatment with curcumin.

CONCLUSION

These results suggest that curcumin can be used to treat inflammatory and atopic diseases through the suppression of TSLP.

Effects of schizandrin on the expression of thymic stromal lymphopoietin in human mast cell line HMC-1

AIMS

Thymic stromal lymphopoietin (TSLP) plays an important role in allergic diseases such as asthma and atopic dermatitis. Schizandrin has various effects such as anti-asthmatic, anti-cancer and anti-inflammatory effects. However, the effect of schizandrin on the production of TSLP has not been clarified. Thus, we investigated how schizandrin inhibits the production of TSLP in the human mast cell line HMC-1 cells.

MAIN METHODS

We used enzyme-linked immunosorbent assay, reverse transcription-polymerase chain reaction, luciferase assay, and Western blot analysis to investigate the effects of schizandrin.

KEY FINDINGS

Schizandrin inhibited the production and mRNA expression of TSLP in HMC-1 cells. The maximal inhibition rate of TSLP production by schizandrin (10 μM) was 68.62 ± 3.47%. Schizandrin inhibited the translocation and luciferase activity of nuclear factor-κB induced by phorbol myristate acetate plus A23187. In the activated HMC-1 cells, the activation of caspase-1 was increased, whereas the activation of caspase-1 was decreased by pretreatment with schizandrin.

SIGNIFICANCE

These results suggest that schizandrin can be used to treat inflammatory and atopic diseases through the inhibition of TSLP.

The suppression of thymic stromal lymphopoietin expression by selenium

Thymic stromal lymphopoietin (TSLP) is a key mediator of allergic diseases such as allergic rhinitis, asthma, and atopic dermatitis. Selenium (Se) has various effects such as antioxidant, antitumor, antiulcer, and anti-inflammatory effects. However, the effect of Se on the production of TSLP has not been clarified. Thus, we investigated how Se inhibits the production of TSLP in the human mast cell line, HMC-1 cells. Se suppressed the production and mRNA expression of TSLP in HMC-1 cells. The maximal inhibition rate of TSLP production by Se (10 μM) was 59.14 ± 1.10%. In addition, Se suppressed the nuclear factor-κB luciferase activity induced by phorbol myristate acetate plus A23187. In the activated HMC-1 cells, the activation of caspase-1 was increased; whereas the activation of caspase-1 was decreased by pretreatment with Se. These results suggest that Se can be used to treat inflammatory and atopic diseases through the suppression of TSLP.