thiourea and Asthma

In recent studies, SPA0355, a thiourea analog, has been demonstrated to possess strong anti-inflammatory activity. However, the mechanisms underlying the effects of SPA0355 on immune-mediated diseases have not been fully defined. The present study was designed to investigate the immunological and molecular mechanisms by which SPA0355 modulates cluster of differentiation of (CD4)(+) T-cell-mediated immune responses in allergic airway inflammation. In vitro studies have shown that SPA0355 suppresses CD4(+) T-cell activation, proliferation, and differentiation via modulation of T-cell receptor (TCR) signal transduction and cytokine-induced Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling. Next, we investigated the efficacy of SPA0355 in ovalbumin (OVA)-induced allergic airway inflammation. Intraperitoneal administration of SPA0355 inhibited inflammatory cell recruitment into the airways as well as the production of Th2 cytokines in bronchoalveolar fluid and suppressed OVA-induced IgE production in serum. Additionally, SPA0355 suppressed mucin production and smooth muscle hypertrophy and prevented the development of airway hyperresponsiveness. Given that allergic airway inflammation is mainly driven by Th2 cell responses, it is highly possible that the defects in CD4(+) T-cell activation and Th2 cell differentiation in the draining lymph nodes and suppressed NF-κB activation in the lungs of SPA0355-treated mice illustrate an immunological mechanism of the preventive effect of SPA0355 on the aforementioned asthmatic characteristics. Collectively, our results suggest that SPA0355 directly modulates Th1 and Th2 responses through the suppression of multiple signaling pathways triggered by TCR or cytokine receptor stimulation, and that SPA0355 has protective effects in a murine model of allergic airway inflammation.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Asthma; Benzoxazines; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; CD4-Positive T-Lymphocytes; Chemotaxis, Leukocyte; Cytokines; Disease Models, Animal; Immunosuppressive Agents; In Vitro Techniques; Lymphocyte Activation; Male; Mice; Mice, Inbred BALB C; Mucins; NF-kappa B; Ovalbumin; Receptors, Antigen, T-Cell; Signal Transduction; Thiourea

Oxidative stress in allergic asthma may result from oxidase activity or proinflammatory molecules in pollens. Signaling via TLR4 and its adaptor Toll-IL-1R domain-containing adapter inducing IFN-β (TRIF) has been implicated in reactive oxygen species-mediated acute lung injury and in Th2 immune responses. We investigated the contributions of oxidative stress and TLR4/TRIF signaling to experimental asthma induced by birch pollen exposure exclusively via the airways. Mice were exposed to native or heat-inactivated white birch pollen extract (BPEx) intratracheally and injected with the antioxidants, N-acetyl-L-cysteine or dimethylthiourea, prior to sensitization, challenge, or all allergen exposures, to assess the role of oxidative stress and pollen-intrinsic NADPH oxidase activity in allergic sensitization, inflammation, and airway hyperresponsiveness (AHR). Additionally, TLR4 signaling was antagonized concomitantly with allergen exposure, or the development of allergic airway disease was evaluated in TLR4 or TRIF knockout mice. N-acetyl-L-cysteine inhibited BPEx-induced eosinophilic airway inflammation and AHR except when given exclusively during sensitization, whereas dimethylthiourea was inhibitory even when administered with the sensitization alone. Heat inactivation of BPEx had no effect on the development of allergic airway disease. Oxidative stress-mediated AHR was also TLR4 and TRIF independent; however, TLR4 deficiency decreased, whereas TRIF deficiency increased BPEx-induced airway inflammation. In conclusion, oxidative stress plays a significant role in allergic sensitization to pollen via the airway mucosa, but the pollen-intrinsic NADPH oxidase activity and TLR4 or TRIF signaling are unnecessary for the induction of allergic airway disease and AHR. Pollen extract does, however, activate TLR4, thereby enhancing airway inflammation, which is restrained by the TRIF-dependent pathway.

Topics: Acetylcysteine; Adaptor Proteins, Vesicular Transport; Animals; Asthma; Betula; Female; Interferon-beta; Mice; Mice, Inbred BALB C; Mice, Knockout; NADPH Oxidases; Oxidative Stress; Pollen; Reactive Oxygen Species; Th2 Cells; Thiourea; Toll-Like Receptor 4

Exposure to chlorine (Cl2) causes airway injury, characterized by oxidative damage, an influx of inflammatory cells and airway hyperresponsiveness. We hypothesized that Cl2-induced airway injury may be attenuated by antioxidant treatment, even after the initial injury.. Balb/C mice were exposed to Cl2 gas (100 ppm) for 5 mins, an exposure that was established to alter airway function with minimal histological disruption of the epithelium. Twenty-four hours after exposure to Cl2, airway responsiveness to aerosolized methacholine (MCh) was measured. Bronchoalveolar lavage (BAL) was performed to determine inflammatory cell profiles, total protein, and glutathione levels. Dimethylthiourea (DMTU;100 mg/kg) was administered one hour before or one hour following Cl2 exposure.. Mice exposed to Cl2 had airway hyperresponsiveness to MCh compared to control animals pre-treated and post-treated with DMTU. Total cell counts in BAL fluid were elevated by Cl2 exposure and were not affected by DMTU treatment. However, DMTU-treated mice had lower protein levels in the BAL than the Cl2-only treated animals. 4-Hydroxynonenal analysis showed that DMTU given pre- or post-Cl2 prevented lipid peroxidation in the lung. Following Cl2 exposure glutathione (GSH) was elevated immediately following exposure both in BAL cells and in fluid and this change was prevented by DMTU. GSSG was depleted in Cl2 exposed mice at later time points. However, the GSH/GSSG ratio remained high in chlorine exposed mice, an effect attenuated by DMTU.. Our data show that the anti-oxidant DMTU is effective in attenuating Cl2 induced increase in airway responsiveness, inflammation and biomarkers of oxidative stress.

Topics: Animals; Asthma; Chlorine; Dose-Response Relationship, Drug; Inhalation Exposure; Irritants; Lung; Male; Mice; Mice, Inbred BALB C; Respiratory Function Tests; Thiourea

Asthma and its exacerbation by air pollution are major public health problems. This investigation sought to more precisely model this disorder, which primarily affects children, by using very young mice. The study first attempted to create allergic airway hypersensitivity in neonatal mice and to determine if physiologic testing of airway function was possible in these small animals. Neonatal mice were sensitized by i.p. injection of ovalbumin (OVA, 5 microg) and alum (1 mg) at 3 and 7 d of age. One week later, mice were challenged by allergen nebulization (3% OVA in PBS, 10 min/d, d 14-16). OVA-exposed mice showed: (1) increased airway hyperresponsiveness (AHR) to methacholine by whole-body plethysmography; (2) eosinophilia in bronchoalveolar lavage (BAL) fluid; (3) airway inflammation using histopathology techniques; and (4) elevated serum anti-OVA immunoglobulin E. Hence, these neonatal mice were successfully sensitized and manifested "asthmatic" responses after allergen challenge. Experiments were conducted to investigate the effect of one surrogate for ambient air particles, residual oil fly ash (ROFA), on this juvenile asthma model. Aerosolized ROFA leachate (supernatant of 50 mg/ml, 30 min, on d 15) had no marked effect alone, but caused a significant increase in AHR and airway inflammation in OVA-sensitized and challenged mice. This synergistic effect was abrogated by the antioxidant dimethylthiourea (DMTU, 3 mg/kg mouse, i.p.). This model may be useful to study air pollution-mediated exacerbation of asthma in children.

Topics: Aerosols; Air Pollutants; Allergens; Animals; Animals, Newborn; Asthma; Bronchial Hyperreactivity; Bronchitis; Carbon; Coal Ash; Enzyme-Linked Immunosorbent Assay; Free Radical Scavengers; Immunoglobulin E; Mice; Mice, Inbred BALB C; Ovalbumin; Particulate Matter; Phenotype; Plethysmography; Serine Proteinase Inhibitors; Thiourea

In a previous study from our laboratory (Akagi and Townley) we reported that basophils from asthmatic patients off medication show spontaneous histamine release (SHR) significantly higher than asthmatic patients on chronic medication. Both groups of asthmatics showed significantly higher SHR than normal subjects. These findings led us to test the in vitro effect of various therapeutic agents on SHR. Theophylline exerted the most pronounced inhibitory effect on SHR (P less than .005). The effects of isoproterenol and PGE1 were significant (P less than .005) but less than theophylline. These in vitro findings led us to evaluate the effect of a single dose, orally administered bronchodilator on in vitro SHR from asthmatic subjects. The effect of theophylline 250 mg and metaproterenol 20 mg on pulmonary function and SHR was evaluated on separate study days. Four of the eight asthmatic subjects showed greater than 10% SHR. The baseline value of SHR in the same individuals on two different study days showed significant correlation (r = .82). A single dose of metaproterenol or theophylline increased the pulmonary function but failed to influence the SHR. Although SHR occurs in asthmatic subjects, it is not influenced by single dose bronchodilation.

Topics: Adult; Alprostadil; Asthma; Basophils; Calcium; Dimaprit; Forced Expiratory Volume; Histamine Release; Humans; Isoproterenol; Magnesium; Male; Metaproterenol; Temperature; Theophylline; Thiourea; Time Factors

Topics: Acetylcholine; Alprostadil; Animals; Asthma; Dimaprit; Immunoglobulin E; Isoproterenol; Male; Mice; Mice, Inbred BALB C; Muscle, Smooth; Prostaglandins F; Pyridines; Thiourea; Trachea

The histamine H2-receptor antagonist metiamide was evaluated in in vitro and in vivo canine models of immediate-type hypersensitivity reactions. At concentrations of 2 and 4 X 10(-4) M, the antagonist significantly increased the amount of histamine present in the medium surrounding passively sensitized canine lung fragments which had been challenged with ascaris antigen. In contrast, the compound was without effect on the release of a slow reacting substance of anaphylaxis. On the basis of these observations metiamide was investigated in an in vivo canine model of allergic asthma. At doses of 10, 30 and 50 mu moles/kg, the antagonist did not enhance the ascaris antigen-induced pulmonary pathophysiology. Similarly, at 10 and 50 mu moles/kg metiamide did not alter histamine-induced increases in pulmonary resistance or decreases in dynamic lung compliance. Insofar as the canine model of allergic asthma may be predictive of the human disease, it could be anticipated that the use of histamine H2-receptor antagonists may not be deleterious to allergic asthmatics.

Topics: Airway Resistance; Animals; Ascaris; Asthma; Dogs; Histamine; Hypersensitivity, Immediate; In Vitro Techniques; Lung; Male; Metiamide; Thiourea; Time Factors