Alveolar Biology: Sex, Age, and Alveolar Turnover

描述（由申请人提供）：我们的长期目标仍然是进行有助于阐明肺泡转换（形成和损失）的调节的实验，希望这些信息可能在治疗上有用。我们过去的工作和建议的工作与支气管肺发育不良（BPD）和慢性阻塞性肺疾病（COPD）最相关，BPD是早产儿的一种疾病，其中肺泡化受阻是一个关键特征，COPD中肺泡破坏导致大量发病率和死亡率。慢性阻塞性肺疾病的肺泡破坏是无情的进行性的，没有补救措施，越来越多的证据表明，女性比男性更容易受到影响，并且在他们的下坡过程更快。自上次提交以来的主要新发现是：1。成年女性雌激素受体（ER）α和ER β k.o.小鼠具有肺泡表型--比野生型小鼠具有更大、更少的肺泡和更小的表面积。2.成年小鼠的卵巢切除术在3周内导致45%的肺泡和13%的肺泡表面积的损失。3.雌激素替代治疗，在肺泡损失发生后，挽救损失。4.作为原理的证明，我们在成年小鼠中显示a）鼻滴注微升（fl）量的弹性蛋白酶在表面活性剂（SAM）中导致严重的弥漫性肺气肿，从而证明弥漫性肺泡递送; B）在SAM中单次鼻滴注GAPDH RNAi（10- 15 mu/l）与scrambled GAPDH RNAi相比，在24 h至7 d内，GAPDH蛋白表达以肺特异性方式下调60-70%;（3）鼻腔滴注SAM中的维甲酸（RA）可使肺特异性标记蛋白的mRNA浓度增加4.6倍，腹腔注射等浓度的RA可使肺中标记蛋白的mRNA增加1.8倍，并使脑和其他器官中标记蛋白的mRNA增加。我们的具体目标，使用野生型和突变小鼠，形态测量，肺基因表达谱，是：1。确定ER肺泡表型开始的发育时间; 2.确定介导卵巢切除术引起的肺泡破坏的ER，和3。确定上游调节剂，启动信号级联所需的雌激素诱导的肺泡再生后，卵巢切除术。我们认为，自第一次修订申请以来产生的新信息，包括以简单、非侵入性、肺特异性方式改变特定基因表达的能力，我们在形态测定方面的丰富经验，以及现在的肺基因谱分析，将使我们能够完成拟议的工作。

DESCRIPTION (provided by applicant): Our long range goal remains performing experiments that help elucidate the regulation of alveolar turnover (formation and loss) in the hope this information might be therapeutically useful. Our past, and proposed, work are most relevant to bronchopulmonary dysplasia (BPD), a condition of very prematurely born infants in which arrested alveolarization is a key feature, and chronic obstructive pulmonary disease (COPD), in which alveolar destruction causes substantial morbidity and mortality. There is no remediation for the relentlessly progressive alveolar destruction of COPD, to which increasing evidence suggests women are more susceptible than men, and in whom the downhill course is more rapid. Key new findings since the last submission are: 1. Adult female estrogen receptor (ER)alpha and ERbeta k.o. mice have an alveolar phenotype - larger and fewer alveoli with less surface area than wildtype mice. 2. Ovariectomy in adult mice results, within 3 weeks, in a loss of 45% of alveoli and 13% of alveolar surface area. 3. Estrogen replacement, after alveolar loss has occurred, rescues the loss. 4. As proof of principle, we show in adult mice a) nasal instillation of microliter (fl) amounts of elastase in surfactant (SAM) resulted in severe diffuse emphysema thereby demonstrating diffuse alveolar delivery; b) a single nasal instillation of GAPDH RNAi in SAM (10- 15mu/l), compared with scrampled GAPDH RNAi, resulted in a 60-70% down-regulation, in a lung specific manner, of GAPDH protein from 24 h through 7 days; c) nasal instillation of retinoic acid (RA) in SAM caused a 4.6-fold increase in lung concentration of the mRNA of a marker protein in a lung specific manner; an equal concentration of RA given intraperitonealy caused a 1.8-fold increase in the marker mRNA in lung and an increase in brain and other organs. Our specific aims, using wild type and mutant mice, morphometric, and lung gene-expression profiling, are: 1. Determine the developmental time of onset of the ER alveolar phenotype; 2. Identify the ERs that mediate the ovariectomy-induced destruction of alveoli, and 3. Identify the upstream modulators that initiate the signal cascade required for estrogen-induced alveolar regeneration that follows ovariectomy. We think the new information generated since the first amended application, including the ability to alter expression of specific genes in a simple, noninvasive, lung specific manner, our extensive experience with morphometry, and now with lung gene profiling, will allow us to complete the proposed work.