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实验，帮助阐明肺泡转换（形成和丢失）的调节，希望这些信息可能对治疗有用。我们过去和现在的工作主要与支气管肺发育不良（BPD）和慢性阻塞性肺疾病（COPD）相关，前者是早产儿肺泡发育停止的主要特征，后者肺泡破坏导致大量发病率和死亡率。对于慢性阻塞性肺病持续进行性肺泡破坏尚无补救措施，越来越多的证据表明，女性比男性更容易受到影响，而且女性的病情恶化速度更快。自上次提交以来的主要新发现有：1。成年雌性雌激素受体(ER) α和ERbeta k.o.小鼠具有肺泡表型——与野生型小鼠相比，肺泡更大、更少、表面积更小。2. 成年小鼠卵巢切除术的结果是，在3周内，肺泡减少45%，肺泡表面积减少13%。3. 在肺泡损失发生后，雌激素替代可挽救肺泡损失。4. 作为原理证明，我们在成年小鼠中发现a)在表面活性剂（SAM）中鼻腔注入微升（fl）量的弹性蛋白酶导致严重的弥漫性肺气肿，从而显示弥漫性肺泡输送；b)在SAM中单次鼻腔灌注GAPDH RNAi (10- 15mu/l)，与混合GAPDH RNAi相比，GAPDH蛋白在24 h至7天内以肺特异性方式下调60-70%；c)经鼻灌注维甲酸（RA）可使SAM肺特异性标记蛋白mRNA浓度增加4.6倍；腹腔注射相同浓度的RA可导致肺中标记mRNA增加1.8倍，脑和其他器官中标记mRNA增加。我们使用野生型和突变型小鼠、形态计量学和肺基因表达谱的具体目标是：1。确定内质网肺泡表型发病的发育时间；2. 2 .确定介导卵巢切除术引起的肺泡破坏的内质网；确定启动信号级联所需的上游调节剂雌激素诱导肺泡再生后，卵巢切除术。我们认为自第一次修改申请以来产生的新信息，包括以简单，无创，肺特异性方式改变特定基因表达的能力，我们在形态测定学方面的丰富经验，以及现在的肺基因分析，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.