Roth Michael, Johnson Peter R A, Rüdiger Jochen J, King Gregory G, Ge Qi, Burgess Janette K, Anderson Gary, Tamm Michael, Black Judith L
Department of Pharmacology and The Woolcock Institute of Medical Research, University of Sydney, NSW 2006, Australia.
Lancet. 2002 Oct 26;360(9342):1293-9. doi: 10.1016/S0140-6736(02)11319-5.
Increased airway smooth muscle bulk is a pathological feature of asthma. Asthma is well controlled by the combined inhalation of glucocorticoids and beta2-adrenoceptor agonists. The basic molecular mechanism of the interaction of the two drugs on proliferation of airway smooth muscle cells is yet to be identified. Our aim was to elucidate how glucocorticoids and beta2 agonists affect the growth of human bronchial airway smooth muscle cells.
We assessed the effect of formoterol and budesonide on the activation and function of transcription factors by immunohistochemistry, western blotting, DNA mobility shift assay, and a luciferase reporter gene assay. The effect of the drugs and the involvement of specific transcription factors on cell proliferation was ascertained by direct cell count and confirmed by thymidine incorporation.
Both classes of drugs (10(-8) mol/L) activated C/EBP-alpha and the glucocorticoid receptor with different kinetic profiles, and inhibited proliferation. The combination of lower doses of drugs (10(-12) to 10(-9) mol/L) resulted in a synchronised activation of the transcription factors and an enhanced antiproliferative effect. The action of the drugs alone or in combination on transcription-factor activity and proliferation was suppressed by either depletion of C/EBP-alpha or in the presence of a glucocorticoid-receptor blocker.
Our findings could provide one explanation for the interaction of beta2 agonists and glucocorticoids at a molecular level, and indicate that the concentration of inhaled glucocorticoids can be reduced when combined with beta2 agonists, minimising the side-effects of the drugs.
气道平滑肌体积增加是哮喘的一个病理特征。哮喘通过联合吸入糖皮质激素和β2肾上腺素能受体激动剂可得到良好控制。这两种药物在气道平滑肌细胞增殖上相互作用的基本分子机制尚待确定。我们的目的是阐明糖皮质激素和β2激动剂如何影响人支气管气道平滑肌细胞的生长。
我们通过免疫组织化学、蛋白质印迹法、DNA迁移率变动分析和荧光素酶报告基因检测来评估福莫特罗和布地奈德对转录因子激活和功能的影响。通过直接细胞计数确定药物对细胞增殖的作用以及特定转录因子的参与情况，并通过胸腺嘧啶核苷掺入法进行确认。
两类药物（10⁻⁸ mol/L）均以不同的动力学模式激活C/EBP-α和糖皮质激素受体，并抑制增殖。较低剂量药物（10⁻¹²至10⁻⁹ mol/L）联合使用导致转录因子同步激活和抗增殖作用增强。单独或联合使用药物对转录因子活性和增殖的作用在C/EBP-α缺失或存在糖皮质激素受体阻滞剂时受到抑制。
我们的研究结果可为β2激动剂和糖皮质激素在分子水平的相互作用提供一种解释，并表明与β2激动剂联合使用时可降低吸入糖皮质激素的浓度，从而将药物副作用降至最低。
