Le Bilarium, Department of Physiology and Biophysics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec,, J1H 5N4 Canada.
Am J Respir Cell Mol Biol. 2010 Nov;43(5):564-75. doi: 10.1165/rcmb.2009-0155OC. Epub 2009 Dec 11.
This study sought to assess putative pathways involved in the anti-inflammatory effects of 17,18-epoxyeicosatetraenoic acid (17,18-EpETE), as measured by a decrease in the contractile reactivity and Ca(2+) sensitivity of TNF-α-pretreated human bronchi. Tension measurements performed in the presence of 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA), a soluble epoxide hydrolase (sEH)-specific inhibitor, demonstrated that 17,18-EpETE reduced the reactivity of TNF-α-pretreated tissues. The overexpression of sEH detected in patients with asthma and TNF-α-treated bronchi contributed to the maintenance of hyperresponsiveness in our models, which involved intracellular proinflammatory cascades. The inhibition of peroxisome proliferator-activated receptor (PPAR)γ by GW9662 abolished 17,18-EpETE + AUDA-mediated anti-inflammatory effects by inducing IκBα degradation and cytokine synthesis, indicating that PPARγ is a molecular target of epoxy-eicosanoids. Western blot analysis revealed that 17,18-EpETE pretreatment reversed the phosphorylation of p38 mitogen-activated protein kinase (p38-MAPK) induced by TNF-α in human bronchi. The Ca(2+) sensitivity of human bronchial explants was also quantified on β-escin permeabilized preparations. The presence of SB203580, a p38-MAPK inhibitor, reversed the effect induced by epoxy-eicosanoid in the presence of AUDA on TNF-α-triggered Ca(2+) hypersensitivity by increasing the phosphorylation level of PKC Potentiated Inhibitor Protein-17 (CPI-17) regulatory protein. Moreover, PPARγ ligands, such as rosiglitazone and 17,18-EpETE, decreased the expression of CPI-17, both at the mRNA and protein levels, whereas this effect was countered by GW9662 treatment in TNF-α-treated bronchi. These results demonstrate that 17,18-EpETE is a potent regulator of human lung inflammation and concomitant hyperresponsiveness, and may represent a valuable asset against critical inflammatory bronchial disorder.
本研究旨在评估 17,18-环氧二十碳四烯酸（17,18-EpETE）抗炎作用的潜在途径，其通过降低 TNF-α预处理的人支气管的收缩反应性和 Ca(2+)敏感性来衡量。在 12-(3-金刚烷-1-基-脲基)-十二烷酸（AUDA）存在下进行的张力测量表明，17,18-EpETE 降低了 TNF-α预处理组织的反应性。在哮喘患者和 TNF-α处理的支气管中检测到可溶性环氧化物水解酶 (sEH)的过表达有助于维持我们模型中的高反应性，这涉及细胞内促炎级联反应。过氧化物酶体增殖物激活受体 (PPAR)γ 的抑制通过诱导 IκBα降解和细胞因子合成而消除 17,18-EpETE+AUDA 介导的抗炎作用，表明 PPARγ 是环氧二十碳烯酸的分子靶标。Western blot 分析显示，17,18-EpETE 预处理逆转了 TNF-α诱导的人支气管中 p38 丝裂原激活蛋白激酶 (p38-MAPK)的磷酸化。还对β-埃斯卡林通透制备的人支气管外植体的 Ca(2+)敏感性进行了定量。p38-MAPK 抑制剂 SB203580 的存在逆转了环氧-eicosanoid 在 AUDA 存在下对 TNF-α触发的 Ca(2+)超敏反应的作用，通过增加 PKC 增强抑制剂蛋白-17 (CPI-17)调节蛋白的磷酸化水平。此外，PPARγ 配体，如罗格列酮和 17,18-EpETE，降低了 CPI-17 的表达，无论是在 mRNA 还是蛋白水平，而这种作用在 TNF-α处理的支气管中被 GW9662 处理所抵消。这些结果表明 17,18-EpETE 是人类肺部炎症和伴随的高反应性的有效调节剂，可能是对抗严重炎症性支气管疾病的有价值的资产。
