NEUROPEPTIDES IN LUNG DEVELOPMENT AND INJURY

我们的长期目标是阐明蛙皮素样蛋白的作用 灵长类肺神经内分泌细胞的多肽(BLP) 肺发育及其在治疗中的临床应用价值 早产儿预防呼吸窘迫综合征(RDS)和 支气管肺发育不良(BPD)。BLP可能会参与到 哺乳动物的肺发育正常，因为在 胎儿肺。我们之前展示了哺乳动物的瞬时表达 妊娠中期人胎肺近远端BLP mRNAs的表达 时尚与航空公司的增长是同步的。宫内BLP 给药加速胎儿肺的生长和成熟；内源性 用抗BLP单抗阻断肺成熟。单元格 表面酶CE10/中性内肽酶24.11(CD10/NEP)已被发现 水解和灭活BLP，这是正常支气管的有丝分裂原 上皮细胞、肺成纤维细胞和许多小细胞癌 肺脏的。SCH32615增强人胎儿对CD10/NEP的抑制作用 器官培养中的肺生长与小鼠的生长和成熟 胎儿肺在宫内。所有这些作用都被BLP受体阻断 对抗者。有可能用外源性BLPS或 通过抑制CD10/NEP增强内源性BLP可预防BPD。 狒狒是唯一可以用来研究这一重要问题的动物模型 人类的紊乱。我们的第一个目标是描述PNEC的个体发育和 BLP、BLP受体和CD10/NEP基因在发育正常人群中的表达 在患有肺透明膜病(HMD)和 每桶。其次，我们将确定BLPS与 地塞米松(DEX)和/或甲状腺激素(T4)对灵长类胎儿肺的作用 器官培养中的生长和成熟是活体研究的前奏。 通过~3H-胸腺嘧啶核苷掺入细胞核来评估生长情况 DNA、增殖细胞核抗原免疫组织化学染色和组织病理学检查。成熟期将是 用~3H-胆碱掺入表面活性磷脂进行评价； 组织病理学和电子显微镜.标记的免疫染色 分化的II型细胞和PNECs；及相关mRNA的定量 表面活性物质磷脂合成水平。第三，我们将调查 BLPS与其他药物的最佳组合(S)的体内效应 对妊娠140天的狒狒胎肺生长发育和成熟的影响 将如上所述进行评估。第四，我们将确定是否 最好的治疗方案被证明可以促进肺成熟 目标3下的生长抑制改善了胎儿的临床结局 巴布亚在怀孕140天出生，我们的主要关注点是BPD。 最后，我们将评估PNEC的变化和BLP、BLP的表达 受体和CE10/NEP基因在体内发育肺中的表达 地塞米松加T4或维甲酸(RA)对正常狒狒的治疗 在HMD和BPD的动物中也是如此。这项调查将是一个至关重要的 拉开了这些药物在临床医学中应用的序幕。

Our long-term objectives are to clarify the role of bombesin-like peptides (BLPs) from pulmonary neuroendocrine cells (PNECs) in primate lung development and to determine their clinical usefulness in treating premature infants to prevent respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD). BLPs are likely to participate in normal mammalian lung development because high BLP levels are found in fetal lung. We previously demonstrated transient expression of mammalian BLP mRNAs in mid-gestation human fetal lung in a proximal-to distal fashion in parallel with growth of the airways. In utero BLP administration accelerated fetal lung growth and maturation; endogenous lung maturation was blocked by an anti-BLP monoclonal antibody. the cell surface enzyme CE10/neutral endopeptidase 24.11 (CD10/NEP) has been found to hydrolyze and inactivate BLPs, which are mitogens for normal bronchial epithelial cells, pulmonary fibroblasts, and many small cell carcinomas of the lung. Inhibition of CD10/NEP by SCH32615 potentiated human fetal lung growth in organ cultures and both growth and maturation in murine fetal lung in utero. All of these effects were blocked by BLP receptor antagonists. It is possible that treatment with exogenous BLPs or potentiation of endogenous BLPs by CD10/NEP inhibition might prevent BPD. The baboon is the only available animal model to study this important human disorder. Our First Aim is to characterize PNEC ontogeny and the expression of BLP, BlP receptor, and CD10/NEP genes in developing normal fetal baboon lung and in animals with hyaline membrane disease (HMD) and BPD. Second, we will determine he optimal combination of BLPs with dexamethasone (DEX) and/or thyroid hormone (T4) for primate fetal lung growth and maturation in organ cultures as a prelude to in vivo studies. Growth will be assessed using: 3H-thymidine incorporation into nuclear DNA; PCNA immunostaining; and histopathology. Maturation will be assessed using: 3H-choline incorporation into surfactant phospholipids; histopathology and electron microscopy; immunostaining for markers of differentiated type II cells and PNECs; and quantitation of relative mRNA levels for surfactant phospholipid synthesis. Third, we will investigate in vivo effects of the optimal combination(s) of BLPs with other agents on baboon fetal lung growth and maturation at 140 days gestation, which will be assessed as described above. Fourth, we will determine whether the best treatment regimen shown to enhance lung maturation without growth inhibition under Aim 3 improves the clinical outcome of fetal baboons delivered at 140 days gestation, with our major focus on BPD. Finally, we will assess alterations in PNECs and expression of BLP, BLP receptor, and CE10/NEP genes in developing lung following in vivo treatment with Dex plus T4, or with retinoic acid (RA) in normal baboons and in animals with HMD and BPD. This investigation would be a critical prelude to the application of these agents in clinical medicine.