In vivo gene transfer study for pathogenesis of lung injury. Endothelin and development of obliterative bronchiolitis

背景闭塞性细支气管炎（OB）是一种病变，导致当损伤的小传导气道修复的纤维肉芽组织增生。OB已成为肺和心肺移植中发病率和死亡率的主要原因。内皮素-1（ET-1）最初被发现是一种缩血管肽，对血管平滑肌细胞和气道上皮细胞具有促有丝分裂活性。据报道，在肺移植后OB或慢性排斥反应患者中，内皮素产生过量。局部过度表达的ET-1是否在OB的发病机制中具有潜在影响尚不确定。方法.我们使用紫外线照射灭活的日本血凝病毒（HVJ）脂质体介导的体内基因转移局部过表达ET-1。将ET-1前体和高迁移率族蛋白1（HMG 1）的质粒DNA共包封于脂质体中，通过HVJ介导的膜融合技术将其导入气道上皮细胞中，并与对照组进行比较。 ...更多信息 锡永。对照动物接受具有空表达盒的HVJ-脂质体滴注。为确定转染效率，引入含β-半乳糖苷酶基因的HVJ脂质体。采用组织化学方法检测ET-1和β-半乳糖苷酶的表达。结果在体内基因转移β-gal后1周，支气管上皮肺泡细胞和肺泡巨噬细胞被染成蓝色（X-Gal），表明β-gal活性。在动物体内转染prepro-ET-1基因后1至2周，在肺泡二管和小传导气道中观察到增生的结缔组织斑块，表明组织学上独特的闭塞性细支气管炎。在气道上皮、增生结缔组织和肺泡细胞中可见强的ET-1样免疫反应。在对照动物中未观察到组织病理学变化。总结和未来的方向。这一结果首次提示ET-1可能在OB的发病机制中起重要作用，推测其可能参与了OB的“共同终末通路”。然而，ET-1的促有丝分裂信号转导机制、对成纤维细胞增殖的调节以及与其他细胞因子或生长因子的相互作用目前仍有待阐明。ET-1在OB发生发展中的具体作用有待进一步研究。综上所述，我们得出结论，局部过度表达的ET-1在OB的发病机制中具有关键作用。这一证据表明，药理学拮抗剂或抑制剂可能能够控制OB患者的疾病进展，这是一个潜在的临床意义。少

Background. Obliterative bronchiolitis (OB) is a lesion that results when injury to small conducting airways is repaired by a proliferation of fibrous granulation tissue. OB has emerged as a main cause of morbidity and mortality in the setting of lung and heart-lung transplantation. Endothelin-1 (ET-1) initially discovered as a vasoconstrictive peptide, has a mitogenic activity on vascular smooth cells and airway epithelial cells. Overproduction of endothelin has been reported in patients with OB or chronic rejection after lung transplantation. It is still undetermined whether locally overexpressed ET-1 has a potential impact in the pathogenesis of OB. Methods. We locally overexpressed ET-1 using ultraviolet irradiation-inactivated hemagglitinating virus of Japan (HVJ)-liposome-mediated in vivo gene transfer. Plasmid DNA of prepro-ET-1 and high mobility group 1 (HMG1) protein were co-encapsulated in liposomes, and were introduced into airway epithelial cells by HVJ-mediated membrane fu … More sion. Control animals received instillation of HVJ-liposome with an empty expression cassette. To confirm the efficiency of transfection, HVJ liposome with β-galactosidase gene was introduced. The expression of ET-1 and β-galactosidase was assessed by histochemistry. Results. Bronchial epithelium alveolar cells and alveolar macrophage were stained blue (X-Gal) 1 week after in vivo gene transfer of β-gene, indicating β-gal activity. In animals 1 to 2 weeks after in vivo transfection of prepro-ET-1 gene, hyperplastic connective tissue plaque was seen in the alveolar duet and small conducting airway, indicating histologically distinctive bronchiolitis obliterans. Strong ET-1 like immunoactivies were seen in the airway epithelial, hyperplastic connective tissue and alveolar cells. No histopathologic changes were seen in the control animals. Summary and Future Direction. This result first suggests that ET-1 may have an important role in pathogenesis of OB presumably in the "common final pathway". However, the mechanism of mitogenic signaling by ET-1, its regulation of fibroblast proliferation, and its interaction with other cytokines or growth factors remained to be clarified at present. Further studies are needed to ascertain the specific role of ET-1 in the progression of OB. In summary, we conclude that local overexpression of ET-1 has a key role in the pathogenesis of OB. This evidence suggests the potential clinical implication that a pharmacological antagonist or inhibitor may be able to control the progression of this disease in patients with OB. Less