Eotaxin-1 (CCL11)是一種特有CC趨化嗜酸性白血球的激素，當呼吸道受到過敏物刺激時，能夠有效的將嗜伊紅性白血球動員至呼吸道中，是氣喘病因上的一個重要角色。而formoterol及salmeterol是長效乙型腎上腺素作用劑，已廣泛的用於氣喘的吸入性治療。然而此作用劑對於支氣管上皮細胞的eotaxin-1表現作用仍是有很多不了解的。本研究利用人類支氣管上皮細胞株(BEAS-2B) 分別給予formoterol及salmeterol再加入IL-4的刺激，以酵素免疫法(ELISA assay) 及real-time PCR等測定，並利用西方墨點法及細胞免疫螢光染色測其在細胞核內外的p-STAT6的反應。結果發現，formoterol及salmeterol (10-7~10-10 M)能夠明顯向下調節IL-4所誘發BEAS-2B細胞eotaxin-1的表現。透過專一的乙型腎上腺素拮抗劑ICI 118551，可阻斷formoterol/salmeterol向下調節IL-4所誘發BEAS-2B細胞eotaxin-1的作用。cAMP活化劑 (forskolin)具有劑量依存性地直接抑制IL-4所誘發BEAS-2B細胞的eotaxin-1表現。藉由西方墨點法及細胞免疫螢光染色所得到的結果是formoterol在濃度10-7M可以抑制細胞核內p-STAT6的表現。實驗結果證實吸入長效的乙型作用劑，formoterol及salmeterol在BEAS-2B細胞株中可以向下調節IL-4所誘發的eotaxin-1表現，而此作用乃經由乙型腎上腺受體以及cAMP。其中formoterol在高濃度時可以向下調控p-STAT6的表現量並且阻斷IL-4的訊息傳遞機制。 Eotaxin-1 (CCL11), an eosinophil-specific C-C chemokine, is a potent chemoattractant for mobilization of eosinophils into airways after allergic stimulation. Eotaxin-1 could recruit eosinophils into inflammatory sites, and play a role in the pathogenesis of asthma. Formoterol and salmeterol are two inhaled long acting β2adrenoceptor agonists, widely used for the local treatment of asthma. However, little is known about their effects on the eotaxin-1 expression of bronchial epithelial cells. BEAS-2B cells were stimulated by adding IL-4 with or without 2h pretreatment of formoterol or salmeterol. The protein and mRNA expression of eotaxin-1 were measured by ELISA assay and real-time PCR, respectively. Effects of formoterol and salmeterol on nuclear and cytosolic p-STAT6 expression were evaluated by Western blot and immunofluorescence study. Formoterol and salmeterol (10-7~10-10 M) could significantly downregulate IL-4-induced eotaxin-1 expression in BEAS-2B cells. A specific β2 adrenoceptor antagonist (ICI 118,551) reversed their suppression of eotaxin-1 production. Forskolin, an cAMP activator, could also suppress the expression of eotaxin-1 by IL-4 in a dose dependent manner (10-7~10-10M). The Western and immunofluorescence studies demonstrated that formoterol 10-7M could suppress the nuclear expression of p-STAT6. Formoterol and salmeterol, two inhaled long-acting β2 agonists, downregulate IL-4- induced eotaxin-1 expression in BEAS-2B cells. The effect may be mediated via the β2 adrenoceptor, and cAMP. Formoterol downregulates p-STAT6 expression at higher concentration, and this further turn off the IL-4 signaling.
