Identification of transcription factors of contractile element of bronchial smooth muscle and its change in activity at airway hyperresponsiveness

从药理学和分子生物学角度探讨过敏性哮喘气道高反应性(AHR)的发病机制。取得了以下研究成果：1.反复抗原攻击大鼠分离的支气管对内皮素-1(ET-1)的收缩反应增强。在增强的ET-1诱导的收缩中，参与了Ca~(2+)和Gt~(2+)敏化现象的增加，CTI-17和肌球蛋白轻链激酶的磷酸化(激活)增强。2.反复抗原攻击后，大鼠支气管肌中基质金属蛋白酶-12(MMP12)基因和蛋白的表达和活性均显著升高，提示MMP一12参与了ABR的发生。3.采用蛋白质/DNA芯片技术，对经抗原暴露后可能被激活的支气管平滑肌转录因子进行了检测。在被暴露抗原激活的转录因子中，发现USF-1、Sp1、NF-EL、STAT5和STAT6是与RhoA启动子区域4的元件结合的转录因子。5.他汀类药物洛伐他汀体内给药可抑制反复抗原攻击所致大鼠的AHR。结果表明，洛伐他汀还可抑制RhoA向细胞膜的转位。这些发现提示他汀类药物可能对改善哮喘患者的AHR有效。6.糖皮质激素对哮喘的治疗作用是通过抑制抗原暴露时支气管平滑肌中RhoA的上调而发挥作用的。

The mechanisms of pathogenesis of airway hyperresponsiveness(AHR) in allergic bronchial asthma were investigated pharmacologically and molecular biologically. The following results were obtained.1. The contractile responsiveness to endothelin-1(ET-1) was increased in the bronchi isolated from rats subjected with repeated antigen challenges. In the augmented ET-1-induced contractility an increase in Ca^<2+> sensitization phenomenon was involved ; phosphorylations(activations) of CTI-17 and myosin light chain kinase were enhanced. 2. The expressions and activations of matrix metalloproteinase(MMP)-12 mRNA and protein of bronchial muscle were increased by repeated antigen challenges, suggesting that MMP-12 is responsible for ABR. 3. The probable transcription factors in bronchial smooth muscle which are activated by antigen exposure were examined covering it using nuclear extraction of the muscle by the method of protein/DNA array method. Among the transcription factors activated by exposuring antigen, it was found that USF-1, Sp1, NF-El, STAT5 and STAT6 are the transcription factors that have potency to bind to the elements of RhoA promoter area 4. Interleukin-13 was demonstrated to induce AHR through the transcription factor STAT6. 5. Lovastatin, one of the statins, when administered in vivo, inhibited the AHR in rats generated by repeated antigen challenges ex they It was shown that at that time, lovastatin also inhibited the translocation of RhoA to cell membrane. These findings suggest that statins may be effective for improvement of AHR in patients with bronchial asthma. 6. It was also suggested that glucocorticoids exert effectiveness for bronchial asthma by inhibiting the RhoA upregulation seen in the bronchial smooth muscle at antigen-exposure.