Development of Regenerative Medicine for COPD

用GFP基因重组C57BL/6小鼠的骨髓，获得GFP嵌合体小鼠。该嵌合体小鼠用内毒素复制急性肺损伤模型，分别于1、2、6个月取肺组织单细胞悬液进行肺细胞分析。使用几个干细胞标记物进行FACS分析。结果表明，急性肺损伤后6个月，肺泡壁GFP阳性细胞比例逐渐降低。慢性期现存肺的内源性干细胞在损伤后的修复过程中表现出一定的相关性，而骨髓来源的干细胞在急性修复期起主要作用。此外，肺内源性干细胞群体中不存在GFP阳性细胞，提示骨髓细胞不是肺内源性干细胞的来源。这些数据表明，不仅是骨髓来源的细胞，而且存在的内源性干细胞在急性肺损伤的修复过程中也是重要的。然后，检测肺内源性干细胞在肺气肿肺再生模型中的作用。本研究采用肝细胞生长因子(HGF)诱导的弹性酶诱导的肺气肿肺再生模型。结果发现，肺组织中CD34等干细胞标记物的细胞群数量增加，这些细胞是HGF诱导受损肺再生所必需的。此外，还阐明了HGF可以增加这些肺内源性干细胞的数量，并促进这些干细胞群向成熟的肺细胞分化。这些结果正在《分子疗法》杂志上进行修订。

The bone marrow of the C57BL/6 mouse was reconstituted with GFP-transgenic, and the GFP-chimera mouse was made. The acute lung injury was developed by LPS in this chimera mouse, and the lung cells were analyzed by obtaining single cell suspension from the pulmonary tissue after 1, 2 or 6 months of LPS-instillation. FACS analyses were performed using several stem cell markers. As a result, the ratio of the GFP-positive cells in the alveolar walls gradually decreased at the stage of 6 months after acute lung injury. The endogenous stem cells of existing lungs in the chronic phase shows relations in the repair processes after the injury though the bone marrow-derived cell plays a major role at the acute repair period. Moreover, the GFP-positive cells did not exist in the population of lung endogenous stem cells, suggesting that the bone marrow cells were not a source of lung endogenous stem cells. These data suggested that not only the bone marrow-derived cell but also existing endogenous stem cells were important in repair processes of acute lung injury. Then, the role of the lung endogenous stem cells in the lung regeneration model from pulmonary emphysema was examined. The hepatocyte growth factor (HGF)-induced lung regeneration model in the elastase-induced emphysema was utilized for this study. As a result, increasing the number of cell groups with the stem cell markers such as CD34 in the pulmonary tissue was observed, and these cells were necessary for HGF-induced regeneration of the destroyed lungs. Moreover, it was clarified for HGF to increase the number of such lung endogenous stem cells, and to promote the differentiation of these stem cell groups into the mature lungs cells. These results are being in under revision in the Molecular Therapy.