OZONE AND HYPEROXIA-INDUCED AIRWAY EPITHELIAL INJURY

吸入臭氧和高浓度氧气会 引起纤毛气道上皮弥漫性损伤， 中性粒细胞募集和气道高反应性。 变更 花生四烯酸（AA）产生的类花生酸代谢物的prolife 被认为是导致 由这些氧化气体引起的气道功能障碍。 我们观察到 体外暴露培养的人气管上皮（TE）细胞， 减少TE细胞产生前列腺素E2（PGE 2）， 环氧合酶（CO）代谢产物与支气管扩张剂、地塞米松和 细胞保护特性，伴随着15- 臭氧暴露后脂氧合酶（15-LO）活性和TE增加 出现延迟，新生成的15-HETE被保留 在细胞内并选择性地酯化成磷脂酰肌醇（PI）， 在信号传导过程中起中心作用的磷脂。 在 在几种模型中，中性粒细胞粘附于靶细胞 对有效的嗜中性粒细胞介导的细胞毒性至关重要。 我们有 表明人嗜中性粒细胞粘附于 臭氧损伤的TE细胞。 在气道中，协同的跨细胞AA 募集的中性粒细胞与损伤气道上皮细胞的代谢 细胞可能直接或间接通过增加中性粒细胞 激活，诱导进一步的上皮细胞损伤。的目标 这些研究是为了调查暴露在空气中的一些机制， 培养的人TE细胞的环境相关浓度 臭氧或高氧气氛抑制细胞CO，并评估 转录和跨国过程调节CO的回收 活性和氧化剂气体暴露后增加的15-HETE产生。 我们还将确定氧化剂气体产生的类花生酸- 暴露的TE细胞，单独或通过跨细胞嗜酸性TE细胞 处理，直接损伤TE细胞和/或增强嗜酸性粒细胞介导的 上皮损伤 最后，我们将评估是否酯化15- HETE到PI改变培养的人TE的细胞内信号转导 通过表征由15-HETE-PI产生的双甘油（DG）物质 响应于氧化剂气体暴露或完整细胞中的活化， 它们与PKC同工酶的体外相互作用。 更好地理解 臭氧或高氧损伤气道的病理过程 上皮和/或促进嗜酸性粒细胞介导上皮损伤可 提出了预防或限制人类这种损伤的治疗策略。

Inhalational exposure to ozone and high concentrations of oxygen can cause diffuse injury to the ciliated airway epithelium accompanied by neutrophil recruitment and airway hyperresponsiveness. Alternations in the prolife of eicosanoids metabolites of arachidonic acid (AA) produced by injured airway epithelial cells have been postulated to contribute to the airway dysfunction induced by these oxidant gases. We have observed that in vitro exposure of cultured human tracheal epithelial (TE) cells to ozone decreases TE cell production of prostaglandin E2 (PGE2), a cyclooxygenase (CO) metabolite with bronchodilator, antiinflammatory and cytoprotective properties, concomitant with preservation of 15- lipoxygenase (15-LO) activity and increased TE after ozone exposure appears to be delayed, and newly generated 15-HETE is retained intracellularly and selectively esterified to phosphatidylinositol (PI), a phospholipid with a central role in signal transduction processes. In several models, adhesion of neutrophils to target cells has been shown to be critical for effective neutrophil-mediated cytotoxicity. We have demonstrated a marked increase in adherence of human neutrophils to ozone-injured TE cells. In the airway, cooperative transcellular AA metabolism between recruited neutrophils and injured airway epithelial cells might directly, or indirectly through increased neutrophil activation, induce further epithelial cell injury. The objectives of these studies are to investigate some of the mechanisms by which exposure of cultured human TE cells to environmentally relevant concentrations of ozone or hyperoxic atmospheres inactivate TE cell CO, and assess the transcriptional and transnational processes regulating recovery of CO activity and increased 15-HETE production following oxidant gas exposure. We will also determine whether cicosanoids generated by oxidant gas- exposed TE cells, alone or through transcellular neutrophil-TE cell processing, directly injure TE cells and/or enhance neutrophil-mediated epithelial injury. Lastly, we will assess whether esterification of 15- HETE to PI alters intracellular signal transduction in cultured human TE cells by characterizing diglycerol (DG) species generated from 15-HETE-PI in response to oxidant gas exposure or activation in intact cells and their interaction with PKC isoenzymes in vitro. A better understanding of the pathologic processes by which ozone or hyperoxia injure airway epithelium and/or promote neutrophil-mediated epithelial damage may suggest therapeutic strategies to prevent or limit such injury in man.