guanosine-5--o-(3-thiotriphosphate) and Asthma

Topics: Airway Resistance; Animals; Anti-Asthmatic Agents; Asthma; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Cell Count; CHO Cells; Cricetinae; Cricetulus; Guanosine 5'-O-(3-Thiotriphosphate); Histamine Agonists; Rats; Receptors, G-Protein-Coupled; Receptors, Histamine; Receptors, Histamine H4; Serotonin

CC chemokine receptor 4 (CCR4) is generally recognized as a preferential marker for T helper 2 cells, and we have previously reported morpholine-derivative CCR4 antagonists, RS-1154 and RS-1269. Here, we investigate the pharmacological profiles of a novel pyrimidine-derivative CCR4 antagonist, 2-{4-[2-(diethylamino)ethoxy]phenyl}-N-(2,4-difluorobenzyl)-5-fluoropyrimidin-4-amine (RS-1748), which showed potency to inhibit the bindings of [(125)I]CCL17 and [(35)S]GTPgammaS to human CCR4-expressing Chinese hamster ovary (CHO) cells with IC(50) values of 59.9 nM and 18.4 nM, respectively. Furthermore, RS-1748 inhibited ovalbumin-induced airway inflammation in guinea pigs at a dose of 10 mg/kg. These results indicate that RS-1748 would be a promising lead compound for developing a therapeutic agent against asthma.

Topics: Animals; Anti-Inflammatory Agents; Asthma; Bronchial Hyperreactivity; Chemokine CCL17; CHO Cells; Cricetinae; Cricetulus; Guanosine 5'-O-(3-Thiotriphosphate); Guinea Pigs; Humans; Inflammation; Inhibitory Concentration 50; Male; Ovalbumin; Pyrimidines; Receptors, CCR4

We have investigated the exocytotic characteristics of neutrophils from allergic patients and healthy volunteers employing the whole cell membrane capacitance (Cm) measurement. The mean serum IgE level from allergic patients (423.75 +/- 12.75 IU/ml) determined by chemiluminescence immunoassay was much higher than that of healthy volunteers (28.47 +/- 16.68 IU/ml). Intracellular dialysis of buffered Ca2+ and GTPgammaS triggered biphasic exocytosis. The total capacitance increment displayed a steep dependence on pipette free Ca2+ concentration ([Ca2+]p), with maximal stimulation achieved at 10 microM. A significant decrease in the total capacitance increment was observed in the allergic group at [Ca2+]p >10 microM. Moreover, at submaximal stimulatory [Ca2+]p of 1 microM, the maximal rate of exocytosis in allergic patients (Vmax = 20.75 +/- 6.19 fF/s) was much faster than that of the healthy control group (Vmax = 7.97 +/- 2.49 fF/s). On the other hand, the Ca2+-independent exocytosis stimulated by GTPgammaS displayed no significant difference in either the total membrane capacitance increments or the maximal rate of exocytosis. The results suggest that hypersecretion of neutrophils in allergic diseases may involve the development of abnormal Ca2+-dependent exocytosis.

Topics: Adolescent; Adult; Antibody Specificity; Asthma; Biomarkers; Calcium; Chemokines; China; Cytochalasin B; Dose-Response Relationship, Drug; Exocytosis; Female; Guanosine 5'-O-(3-Thiotriphosphate); Humans; Immunoglobulin E; Male; Neutrophil Activation; Neutrophils; Receptors, Chemokine; Receptors, IgE; Rhinitis, Allergic, Perennial; Sensitivity and Specificity