Mechanism of Irradiation Pulmonary Fibrosis

描述（由申请方提供）：电离辐射诱导的肺损伤限制了肺癌和食管癌治疗中的有效辐射剂量递增。辐射诱导的晚期机化性肺泡炎/纤维化的C57 BL/6 J小鼠模型密切遵循人肺辐射损伤的参数。我们已经证明，在肺照射后120-140天，当内皮细胞VCAM-1和ICAM-1上调时，骨髓来源的巨噬细胞迁移到小鼠肺，随后TGF 2介导的骨髓来源的肌成纤维细胞祖细胞（骨髓基质细胞/间充质干细胞）的迁移和增殖，这有助于肺纤维化。肺内锰超氧化物歧化酶-质粒脂质体（MnSOD-PL）基因治疗显着减少这两种迁移。我们现在建议阐明晚期肺损伤的细胞和分子机制，并优化MnSOD-PL的改善。我们将使用雌性C57 BL/6 J小鼠和HSV-TK（单纯疱疹病毒-胸苷激酶）-CCSP+转基因小鼠（其具有更昔洛韦敏感的Clara细胞分泌蛋白阳性肺干细胞），并且对于雄性GFP+骨髓是嵌合的。第一个具体目标测试吸入MnSOD-PL基因治疗通过增强骨髓源性修复性肺泡和支气管干细胞祖细胞的迁移而促进肺照射的假设。第二个特定目的检验周期性重复MnSOD-PL吸入基因疗法通过减少骨髓源性肌成纤维细胞的迁移来减少晚期肺纤维化的假设。第三个具体目标测试了以下假设：将肺靶向过氧化氢酶质粒脂质体吸入到MnSOD-PL中将增强肺辐射保护。方法包括雾化吸入mt-过氧化氢酶-PL和MnSOD-PL在肺照射嵌合小鼠中，通过微型渗透泵连续BUDR标记，细胞分选和组织病理学。这些研究应确定放射性肺纤维化的关键步骤，并确定治疗干预的新靶点，从而减少患者的副作用，并促进复发性胸部癌症的初始治疗或再治疗的剂量递增。

DESCRIPTION (provided by applicant): Ionizing irradiation-induced pulmonary damage limits effective radiation dose escalation in the treatment of lung and esophageal cancer. The C57BL/6J mouse model of irradiation-induced late organizing alveolitis/fibrosis closely follows the parameters of human pulmonary irradiation damage. We have demonstrated that bone marrow origin macrophages migrate to the mouse lung at the time of up regulation of endothelial cell VCAM-1 and ICAM-1 at 120-140 days after pulmonary irradiation, followed by TGF2-mediated migration and proliferation of bone marrow origin myofibroblast progenitor cells (bone marrow stromal cells/mesenchymal stem cells), which contribute to pulmonary fibrosis. Both migrations are significantly reduced by intrapulmonary manganese superoxide dismutase-plasmid liposome (MnSOD-PL) gene therapy. We now propose to elucidate the cellular and molecular mechanism(s) of initiation of the late pulmonary lesion and optimize its amelioration by MnSOD-PL. We will use female C57BL/6J mice and HSV-TK (Herpes Simplex Virus-Thymidine Kinase)-CCSP+ transgenic mice (which have gancyclovir sensitive Clara Cell Secretory Protein positive lung stem cells) and are chimeric for male GFP+ bone marrow. The first specific aim tests the hypothesis that inhalation MnSOD-PL gene therapy facilitates lung irradiation through enhancement of migration of marrow origin reparative alveolar and bronchial stem cell progenitors. The second specific aim tests the hypothesis that periodic repeat MnSOD-PL inhalation gene therapy decreases late pulmonary fibrosis through decreased migration of marrow origin myofibroblasts. The third specific aim tests the hypothesis that adding inhalation of mitochondrially targeted catalase plasmid liposomes to MnSOD-PL will enhance lung radiation protection. Methods include nebulizer-inhalation of mt-catalase-PL, and MnSOD-PL in pulmonary irradiated chimeric mice, continuous BUDR labeling by mini-osmotic pump, cell sorting, and histopathology. These studies should define critical steps in irradiation pulmonary fibrosis and identify new targets for therapeutic intervention, thereby decreasing patient side effects and facilitating dose escalation in the initial treatment or retreatment of recurrent thoracic cancers.