Df Extract Research Articles

Effects of β2-adrenergic agonists on house dust mite-induced adhesion, superoxide anion generation, and degranulation of human eosinophils.

BackgroundEven in subjects who are not sensitized to house dust mite (HDM), allergic symptoms can be clinically aggravated by exposure to dust. We previously reported that Dermatophagoides farinae (Df), an important HDM, or Der f 1, a major allergen of Df, induced the effector functions of eosinophils, which may be an important mechanism for HDM-induced symptoms in nonsensitized patients. In a clinical setting, β2-adrenergic agonists, such as salbutamol and formoterol, are used for the treatment of asthma attacks or exacerbation to release the airway obstruction. Several reports have suggested that some β2-adrenergic agonists have an anti-inflammatory capacity.ObjectiveIn this study, we investigated whether β2-adrenergic agonist could modify the Df- or Der f 1-induced activation of eosinophils.MethodsBlood eosinophils obtained from healthy donors were preincubated with either formoterol (1 μM), salbutamol (1 μM), or buffer control and then stimulated with Df extract (1 μg/mL) or Der f 1 (100 pg/mL). Eosinophil adhesion to intercellular adhesion molecule (ICAM)-1 was measured using eosinophil peroxidase assays. Generation of superoxide anion (O2−) was examined based on the superoxide dismutase-inhibitable reduction of cytochrome C. Eosinophil-derived neurotoxin (EDN) concentrations in cell media were measured by enzyme-linked immunosorbent assay.ResultsFormoterol, but not salbutamol, suppressed the Df- or Der f 1-induced eosinophil adhesion to ICAM-1. Furthermore, formoterol, but not salbutamol, suppressed Df-induced O2− generation or EDN release. Neither formoterol nor salbutamol suppressed spontaneous eosinophil adhesion, O2− generation, or EDN release.ConclusionThese findings suggested that formoterol, but not salbutamol, suppressed Df- or Der f 1-induced eosinophil activation when used at the same concentration. Therefore, formoterol could potentially be used for the treatment of bronchial asthma via both bronchodilation and anti-inflammatory effect.

Antioxidative effect of drumstick (Moringa oleifera L.) flower on the quality and stability of goat meat nuggets

PurposeThis paper aims to explore the application of drumstick (Moringa oleifera) flower (DF) as a functional antioxidative ingredient in goat meat product.Design/methodology/approachDried DF was included in the product formulation at 1% (Treatment I) and 2% (Treatment II) levels. The physicochemical, colour, textural and sensory quality as well as storage stability of nuggets with DF were determined against control.FindingsThe dried DF was found to be rich source of protein and dietary fibre, possessing good antioxidant potential. Chromatographic analysis of DF extract showed presence of 14 active principles known to have antioxidative properties. Inclusion of dried DF decreased pH values of emulsion (p = 0.005) as well as nuggets (p < 0.001) and increased (p < 0.001) the ash, dietary fibre and phenolic contents. The added DF affected the product’s lightness (p = 0.017), yellowness (p < 0.001, hardness (p < 0.001), adhesiveness (p = 0.032), cohesiveness (p = 0.006), gumminess and chewiness (p < 0.001). Sensory characteristics of control and product with DF were statistically similar except low (p = 0.002) flavour score for Treatment II. DF inclusion lowered (p < 0.001) thiobarbituric acid reactive substances number and total plate count.Research limitations/implicationsDF can be used as a source of antioxidants and dietary fibre in goat meat nuggets to enhance their health value, functionality and storage stability.Originality/valueFoods including goat meat nuggets enriched with goodness of functional ingredients like dietary fibre and natural antioxidants are gaining consumer’s preference globally. Inclusion of drumstick flower in goat meat nuggets significantly increases the dietary fibre and antioxidants making such products healthier and more stable. Consumption of goat meat nuggets added with drumstick flower is expected to improve consumer’s well-being as well.

Dermatophagoides farinae Upregulates the Effector Functions of Eosinophils through αMβ2-Integrin and Protease-Activated Receptor-2

Background: Even in subjects who are not sensitized to house dust mite (HDM), allergic symptoms can be aggravated by exposure to dust, suggesting that innate immune responses may be involved in these processes. Since eosinophils express pattern recognition receptors, HDM may directly upregulate eosinophil functions through these re ceptors. The objective of this study was to examine whether Dermatophagoides farinae (Df), a representative HDM, or Der f 1, a major allergen of Df, modifies the effector functions of eosinophils. Methods: Eosinophils isolated from the blood of healthy donors or allergic patients were stimulated with Df extract or Der f 1, and their adhesion to recombinant human intercellular adhesion molecule (ICAM)-1 was measured using eosinophil peroxidase assays. Generation of the eosinophil superoxide anion (O₂^–) was examined based on the superoxide dismutase-inhibitable reduction of cytochrome C. Eosinophil-derived neurotoxin (EDN) concentrations in cell media were measured by ELISA as a marker of degranulation. Results: Df extract or Der f 1 directly induced eosinophil adhesion to ICAM-1, O₂^– generation, and EDN release. Anti-αM- or anti-β₂-integrin antibodies or protease-activated receptor (PAR)-2 antagonists suppressed the eosinophil adhesion, O₂^– generation, and EDN release induced by Df extract or Der f 1. Eosinophils from allergic patients showed higher adhesion to ICAM-1 than those from healthy donors. Conclusions: These findings suggested that Df extract and Der f 1 directly activate eosinophil functions through αMβ₂-integrin and PAR-2. Eosinophil activation by HDM may play roles in the aggravation of allergic symptoms, not only in HDM-sensitized patients, but also in nonsensitized patients.

Dragon fruit extract capped gold nanoparticles: Synthesis and their differential cytotoxicity effect on breast cancer cells

Biosynthesis of gold nanoparticles from Dragon fruit extract (DF extract) can be considered as an eco-friendly alternative for synthesis of gold nanoparticles. The aim of this study was to investigate the ability of this fruit to synthesize gold nanoparticles and to study its anticancer activity. The as synthesized gold nanoparticles were characterized by UV-vis spectrophotometry, X-ray diffraction, Fourier Transform Infra-red spectroscopy and Transmission Electron microscopy. The results from XRD and TEM support the biosynthesis of DF extract capped gold nanoparticles (DF-AuNPs) in the size range of 10–20 nm. The DF extract and DF-AuNPs induced significant growth inhibition of MCF-7 breast cancer cells however, no significant toxicity effect was observed on MDA-MB-231 cells.

Beneficial effects of Galectin-9 on allergen-specific sublingual immunotherapy in a Dermatophagoides farinae-induced mouse model of chronic asthma

BackgroundAllergen-specific sublingual immunotherapy is a potential disease-modifying treatment for allergic asthma. Galectin-9 (Gal-9), a β-galactoside-binding protein with various biologic effects, acts as an immunomodulator in excessive immunologic reactions by expanding regulatory T cells (Treg) and enhancing transforming growth factor (TGF)-β signaling. We investigated the efficacy of sublingually administered Gal-9 as an adjuvant to a specific allergen in a Dermatophagoides farinae (Df)-induced mouse model of chronic asthma. MethodsBALB/c mice were intranasally sensitized with Df extract 5 days/week for 5 weeks, and then sublingual Df-allergen extract for 2 weeks (5 days/week). Three days after the final sublingual treatment, mice were intranasally challenged with Df extract. The early asthmatic response (EAR) was evaluated 5 min after the last Df challenge. Airway hyperresponsiveness (AHR) was assayed and bronchoalveolar lavage (BAL) was performed 24 h after the last allergen challenge. Serum IgE and cytokine levels, and number of inflammatory cells in the BAL fluid (BALF) were analyzed. ResultsSublingual Df treatment in the presence of Gal-9, but not alone, significantly reduced AHR; EAR; number of eosinophils and interleukin-13 in the BALF; and serum IgE levels. BALF TGF-β1 levels were significantly increased in the presence of Gal-9 compared with Df alone. Treg depletion blocked the inhibitory effects of Gal-9 on the EAR, AHR, eosinophilic airway inflammation, and Df-specific serum IgE levels, and suppressed BALF TGF-β1 levels. ConclusionsGal-9 exhibited beneficial effects of sublingual Df allergen-specific immunotherapy in a Df-induced mouse model of chronic asthma, possibly by Gal-9-induced TGF-β1 production in the lung.

Dectin-2 Recognition of House Dust Mite Triggers Cysteinyl Leukotriene Generation by Dendritic Cells

House dust mites are a significant source of airborne allergen worldwide, but there is little understanding of how they so potently generate allergic inflammation. We found that extracts from the house dust mites Dermatophagoides farinae (Df) and Dermatophagoides pteronyssinus and from the mold Aspergillus fumigatus stimulated a rapid and robust production of cysteinyl leukotrienes (cys-LTs), proinflammatory lipid mediators, from mouse bone marrow-derived dendritic cells (BMDCs). Con A affinity chromatography of the Df extract revealed that the relevant ligand is a glycan(s), suggesting stimulation via a dendritic cell (DC) lectin receptor. Cys-LT production in BMDCs from wild-type mice was inhibited by spleen tyrosine kinase (Syk) inhibitors and was abolished in BMDCs from FcRgamma-/- mice, implicating either Dectin-2 or DC immunoactivating receptor. Transfection of each receptor in bone marrow-derived mast cells revealed that only Dectin-2 mediates cys-LT production by Df, Dermatophagoides pteronyssinus, and Aspergillus fumigatus. Lentiviral knockdown of Dectin-2 in BMDCs attenuated Df extract-elicited cys-LT generation, thereby identifying Dectin-2 as the receptor. Lung CD11c+ cells, but not peritoneal or alveolar macrophages, also generated cys-LTs in response to Df. These findings place Dectin-2 among the C-type lectin receptors that activate arachidonic acid metabolism and identify the Dectin-2/FcRgamma/Syk/cys-LT axis as a novel mechanism by which three potent indoor allergens may activate innate immune cells to promote allergic inflammation.

Dendritic Cell Production of Cysteinyl Leukotrienes in Response to Allergens

The cysteinyl leukotrienes (cys-LTs) are powerful inflammatory mediators that can be produced by both murine and human dendritic cells (DCs) in response to extracts from house dust mite, but the molecular mechanism is unknown. We have evaluated the requirements for cys-LT generation by murine bone marrow-derived DCs (BMDCs) in response to allergen extracts from the fungus Aspergillus fumigatus (Af), and the house mites Dermatophagoides pteronyssinus (Dp), and Dermatophagoides farinae (Df). BMDCs were generated with granulocyte macrophage colony stimulating factor and evaluated between day 8 and 10. BMDCs produced cys-LTs to extracts from Af, Dp, and Df that peaked by 30 min. There was no response to ovalbumin with or without lipopolysaccharide, to TLR2 agonists, or to NOD agonists. Treatment of the Df extract with heat, nucleases, or proteases did not diminish its activity, and after chloroform-methanol extraction the activity was retained in the aqueous phase. Recombinant Df did not elicit cys-LT production. These results demonstrate that DCs recognize a highly polar, non-proteinous agonist(s) in several common allergens that elicits a rapid and robust production of cys-LTs.

A Novel Atopic Dermatitis Model Induced by Topical Application with Dermatophagoides Farinae Extract in NC/Nga Mice

Atopic dermatitis is a chronically relapsing inflammatory skin disease. Animal models induced by relevant allergens play a very important role in the elucidation of the disease. The patients with atopic dermatitis are highly sensitized with mite allergens such as Dermatophagoides farinae (Df). Therefore, in the present study, we tried to develop a novel model for atopic dermatitis by repeated application with Df extract ointment. Df extract ointment was repeatedly applied to the back of NC/Nga mice together with barrier disruption. Atopic dermatitis-like skin lesions were evaluated by dermatitis scores, skin histology and immunological parameters. The effect of corticosteroid and calcineurin inhibitor was also examined. Repeated application of Df extract ointment caused rapid increase in dermatitis scores. Clinical (skin dryness, erythema, edema and erosion) and histological symptoms (dermal and epidermal thickening, hyperkeratosis, parakeratosis and inflammatory cell infiltration) in this model were very similar to those in human atopic dermatitis. Serum total and Df-specific IgE levels were elevated in this model compared with normal mice, and draining lymph node cells isolated from the mice that exhibited dermatitis produced significant amounts of interleukin-5, interleukin-13 and interferon-gamma after re-stimulation with Df. Furthermore, current first-line drugs for the treatment of human atopic dermatitis, corticosteroid and tacrolimus ointments, were effective against the clinical and histological symptoms in this model. These results suggest that the model we have established is useful for not only elucidating the pathogenesis of atopic dermatitis but also for evaluating therapeutic agents.

Comparison of IL-17 Production by Helper T Cells among Atopic and Nonatopic Asthmatics and Control Subjects

Background: T cells, eosinophils, and neutrophils are strongly involved in the pathogenesis of bronchial asthma. Mechanisms that influence neutrophil accumulation and activation in asthma still remain relatively obscure. There is data indicating that IL-17 is produced by T cells and causes the release of neutrophil-mobilizing cytokines from airway epithelial cells, and that in this way it may regulate airway neutrophilia. Methods: Peripheral blood mononuclear cells (PBMC) obtained from atopic asthmatics (AA), nonatopic asthmatics (NA), and normal control subjects (NC) were stimulated by immobilized anti-CD3 antibody (Ab) plus soluble anti-CD28 Ab or Dermatophagoidesfarinae (Df) extract. Df-reactive T cell clones were established from PBMC of AA and cultured in the presence of various stimulants. The resulting supernatants were assayed for IL-2, IL-4, IL-5, IL-13, IL-17, and IFN-γ by specific ELISAs. Results: PBMC obtained from AA, NA, and NC all produced IL-17 upon immobilized anti-CD3 Ab plus soluble anti-CD28 Ab stimulation. IL-17 production in response to Df extract was significantly induced only in AA. The amount of IL-17 produced by T cell clones stimulated with immobilized anti-CD3 Ab plus soluble anti-CD28 Ab was negatively, but only weakly, correlated with that of IL-4, but not correlated with IL-2, IL-5, IL-13, and IFN-γ production. Conclusion: T cells producing IL-17 in response to Df antigen exist in the peripheral blood of the sensitized AA. IL-17 production might be regulated by unique mechanisms different from those governing Th1 versus Th2 differentiation.

Beneficial Effects of Tissue Inhibitor of Metalloproteinases-2 (TIMP-2) on Chronic Dermatitis

Chronic dermatitis, such as contact dermatitis (CD) or atopic dermatitis (AD), is a longstanding inflammatory skin disease with cutaneous damage such as erosion, ulceration, and lichenification due to itch-induced scratching. The resultant lesion can be considered to be a kind of wound. The tissue inhibitor metalloproteases-2 (TIMP-2) accelerates wound healing by enhancing the proliferation and migration of epidermal keratinocytes and dermal fibroblasts; it is also a physiologic inhibitor of matrix metalloproteinases. The aim of this study was to test the effect of TIMP-2 on chronic dermatitis. NC/Kuj mice were sensitized with Dermatophagoides farinae (Df) extract. Eczema was induced by repeated applications of this mite allergen to the skin of 20 sensitized mice that were maintained under specific pathogen-free conditions. One group of 10 mice was then treated with topical TIMP-2 solution (0.1 ml, 0.5%) for 28 days, and the other with vehicle alone and the effects of TIMP-2 were evaluated macro- and microscopically. The effect on skin barrier function was estimated by measuring transepidermal water loss (TEWL). Scoring of gross skin findings showed that TIMP-2 significantly reduced the severity of eczema (P<0.05) on days 12-28. Histological examination revealed that TIMP-2 treated mice manifested lower degrees of hyperkeratosis, acanthosis, and spongiosis in the epidermis and fewer inflammatory cells in the dermis than vehicle-treated mice. There were significant reductions in the epidermal thickness and dermal inflammatory cells in the TIMP-2 treated animals (P<0.01); their TEWL was significantly decreased on day 28 (P<0.05). Our results suggest that NC/Kuj mice with Df extract-induced chronic eczema may be a useful model for investigating chronic dermatitis, and that TIMP-2 may be a good agent for treating chronic dermatitis as well as chronic ulcers.

Preventive effect of bedding encasement with microfine fibers on mite sensitization

Background: The indoor levels of mite allergens are known to determine the thresholds of sensitization and asthma exacerbation. However, the method for preventing mite sensitization by reducing the levels of house dust mites (HDMs) is not well established. Objective: We investigated whether mite-blocking bedding encasing made from microfine fibers can prevent infants from being sensitized to HDMs. Methods: Fifty-seven Japanese infants with atopic dermatitis who had high levels of IgE antibodies against either egg white, cow's milk, or soybean (but not against HDMs) were randomly chosen and divided into two groups. Thirty families of atopic infants (group A) were instructed to decrease HDMs by controlling the indoor environment, including bedding cleaning, whereas 27 families receiving the same instructions (group B) were further guided to use the Allerguard encasing for quilts and mattresses of all family members. We repeatedly examined Der p 1 + Der f 1 in the infants' mattresses and anti- Dermatophagoides farinae (Df) IgE in the infants' sera, and we performed skin prick tests with Df extract for 1 year. Results: The mite-blocking encasing markedly reduced the levels of Der p 1 + Der f 1 (3.0 μg/g dust for group A vs 0.77 μg/g dust for B, p < 0.001). It also prevented the increase in serum levels of anti-Df IgE (2.5 U/ml for group A vs 0.7 U/ml for group B, p < 0.05) and positive reactions to skin prick testing with Df extract (63% for group A vs 31% for group B, p < 0.02) over 1 year. Conclusion: The bedding encasement with the mite-blocking fibers was effective for preventing atopic infants from being sensitized to HDMs, and it seems to be beneficial to modern busy housekeepers. (J Allergy Clin Immunol 1998;101:28-32.)