Research Unit, University General Hospital Consortium, Valencia, Spain.
Clin Exp Allergy. 2011 Apr;41(4):535-46. doi: 10.1111/j.1365-2222.2011.03715.x.
Oxidative stress is present in airway diseases such as severe asthma or Chronic Obstructive Pulmonary Disease and contributes to the low response to glucocorticoids through the down-regulation of histone deacetylase (HDAC) activity.
To study the effects of the phosphodiesterase (PDE)-3 and 4 inhibitors and their combination vs. glucocorticoids in a model of lipopolysaccharide (LPS)-induced cytokine release in alveolar macrophages under oxidative stress conditions.
Differentiated U937 or human alveolar macrophages were stimulated with H(2) O(2) (10-1000 μM) or cigarette smoke extract (CSE, 0-15%) for 4 h before LPS (0.5 μg/mL, 24 h) addition. In other experiments, cells were pre-treated with dexamethasone or budesonide (10(-9) -10(-6) M), with the PDE4 inhibitor rolipram (10(-9) -10(-5) M), PDE3 inhibitor motapizone (10 μM), 3',5'-cyclic monophosphate enhancer PGE(2) (10 nM), or with the combination of rolipram (10(-6) M)+PGE(2) (10 nM)+motapizone (10 μM) 15 min before oxidants. IL-8 and TNF-α were measured by ELISA and HDAC activity by a colorimetric assay.
Budesonide and dexamethasone produced a concentration-dependent inhibition of the LPS-induced IL-8 and TNF-α secretion with an E(max) about 90% of inhibition, which was reduced by approximately 30% in the presence of H(2)O(2) or CSE. Pre-treatment with rolipram, motapizone or PGE2 only reached about 20% of inhibition but was not affected by oxidative stress. In contrast, PDE4/PDE3 combination in presence of PGE2 effectively inhibited the LPS-induced cytokine secretion by about 90% and was not affected by oxidative stress. Combined PDE4 and PDE3 inhibition reversed glucocorticoid resistance under oxidative stress conditions. HDAC activity was reduced in the presence of oxidative stress, and in contrast to glucocorticoids, pre-treatment with PDE4/PDE3 combination was able to prevent HDAC inactivity.
CONCLUSIONS & CLINICAL RELEVANCE: This study shows that the combination of the PDE3/PDE4 inhibitors prevents alveolar macrophage activation in those situations of glucocorticoid resistance, which may be of potential interest to develop new effective anti-inflammatory drugs in airway diseases.
氧化应激存在于严重哮喘或慢性阻塞性肺疾病等气道疾病中，并通过下调组蛋白去乙酰化酶 (HDAC) 活性导致糖皮质激素反应降低。
研究磷酸二酯酶 (PDE)-3 和 4 抑制剂及其组合在脂多糖 (LPS) 诱导的肺泡巨噬细胞细胞因子释放模型中在氧化应激条件下与糖皮质激素的作用。
在 LPS（0.5 μg/mL，24 小时）添加之前，用 H(2)O(2)（10-1000 μM）或香烟烟雾提取物 (CSE，0-15%）处理分化的 U937 或人肺泡巨噬细胞 4 小时。在其他实验中，细胞用地塞米松或布地奈德（10(-9)-10(-6)M）、PDE4 抑制剂罗利普兰（10(-9)-10(-5)M）、PDE3 抑制剂莫特匹嗪（10 μM）、3',5'-环单磷酸增强剂 PGE(2)（10 nM）或罗利普兰（10(-6)M）+PGE(2)（10 nM）+莫特匹嗪（10 μM）在氧化剂前 15 分钟进行预处理。通过 ELISA 测量 IL-8 和 TNF-α，通过比色法测定 HDAC 活性。
布地奈德和地塞米松对 LPS 诱导的 IL-8 和 TNF-α 分泌呈浓度依赖性抑制，E(max) 约为 90%的抑制作用，但在 H(2)O(2)或 CSE 存在下降低约 30%。罗利普兰、莫特匹嗪或 PGE2 的预处理仅达到约 20%的抑制作用，但不受氧化应激影响。相比之下，PDE4/PDE3 联合在存在 PGE2 的情况下有效抑制 LPS 诱导的细胞因子分泌约 90%，不受氧化应激影响。联合 PDE4 和 PDE3 抑制可逆转氧化应激条件下的糖皮质激素抵抗。HDAC 活性在氧化应激下降低，与糖皮质激素相反，PDE4/PDE3 联合预处理能够防止 HDAC 失活。
这项研究表明，PDE3/PDE4 抑制剂的联合使用可防止肺泡巨噬细胞在糖皮质激素抵抗的情况下激活，这可能对开发气道疾病的新型有效抗炎药物具有潜在意义。
