Role of hepatic and pulmonary P4501A enzymes in neonatal hyperoxic tissue injury

描述(申请人提供)：补充氧气被广泛用于治疗婴儿肺功能不全。在早产儿中，高氧治疗会导致支气管肺发育不良(BPD)和其他多器官衰竭。这项研究的中心假设是，肝脏和肺细胞色素P450(CYP)1A酶对氧气对肺和其他器官的急性和长期损伤起到保护作用。其具体目的是：(1)验证一种假设，即出生前或出生后，野生型(WT)(C57BL/6J)小鼠暴露于细胞色素P4501A1(CYP1A1)诱导剂β-萘黄酮(BNF)会分别导致新生儿高氧暴露引起的急性肺和肝脏损伤以及肺成熟异常的减弱或增强。新生的野生型(WT)(C57BL/6J)小鼠在出生前或出生后接受玉米油(溶剂对照)或BNF的治疗，新生的小鼠将被早产，因为有一种假说认为，缺乏肝细胞色素P1A1或肝脏特异性的细胞色素P1A2基因的新生小鼠更容易受到急性和长期的氧致肺损伤。将新生野生型(C57BL/6J)、Cyp1a1(-/-)、CYP1A2(-/-)或Cyp1a1/1a2双基因敲除小鼠暴露于室内空气或高氧中7天，在选定的时间点研究细胞色素P1a的表达和肺、肝损伤的参数。(3)探讨高氧诱导新生小鼠体内和培养细胞中细胞色素P4501A1表达的分子机制。这个目标有两个子目标：(I)验证高氧通过转录激活相应启动子的机制诱导新生儿CYP1A1/1A2基因表达的假说。(2)探讨人细胞色素P4501A1基因对胎肺细胞的诱导作用机制。我们将验证这样一种假设，即高氧通过AHR与特定的高氧呼吸相互作用而诱导人或小鼠胎肺细胞中CYP1A1的表达。与类似暴露的WT小鼠相比，以肺特异的方式抑制hCYP1A1将不太容易受到高氧肺损伤的影响。建议的研究将为制定预防和治疗早产儿和足月儿BPD和其他疾病的新的合理策略提供概念基础(S)。公共卫生相关性：补充氧气被广泛用于治疗婴儿肺功能不全。在早产儿中，高氧治疗会导致支气管肺发育不良(BPD)和其他多器官衰竭。利用基因敲除和转基因小鼠以及细胞培养模型，该项目旨在开发新的方法来预防和治疗肺(例如，BPD)和其他与高氧相关的疾病。

DESCRIPTION (provided by applicant): Supplemental oxygen is used extensively in the treatment of pulmonary insufficiency in infants. In premature infants, hyperoxic therapies contribute to the development of bronchopulmonary dysplasia (BPD) and other multi-organ failures. The central hypothesis of the proposed study is that hepatic and pulmonary cytochrome P450 (CYP)1A enzymes play a protective role against acute and long-term injury to lung and other organs by oxygen. The specific aims are: (1) To test the hypothesis that prenatal or postnatal exposure of wild type (WT) (C57BL/6J) mice to the cytochrome P4501A1 (CYP1A1) inducer beta-naphthoflavone (BNF) will result in attenuation or potentiation, respectively, of acute lung and liver injury and abnormal lung maturation resulting from neonatal hyperoxic exposures. Newborn wild type (WT) (C57BL/6J) mice are subjected to prenatal or postnatal treatment with corn oil (vehicle control) or BNF, and newborns will be delivered prematurethe hypothesis that newborn mice lacking the genes for CYP1A1 or the liver- specific CYP1A2 will be more susceptible to acute and long-term lung injury induced by oxygen. Newborn wild type (C57BL/6J), Cyp1a1 (-/-), Cyp1a2 (-/-), or Cyp1a1/1a2 double knockout mice will be exposed to room air or hyperoxia for 7 days, and CYP1A expression and parameters of lung and liver injury will be studied at selected time points. (3) To determine the molecular mechanism of CYP1A1 induction by hyperoxia in the newborn mice in vivo and in cultured cells. This aim has two sub-aims: (i) To test the hypothesis that hyperoxia induces CYP1A1/1A2 gene expression in the newborn through mechanisms involving transcriptional activation of the corresponding promoters. (ii) To determine the mechanisms of induction of human CYP1A1 gene on fetal lung cells. We will test the hypothesis that hyperoxia induces CYP1A1 expression in human or mouse fetal lung cells by interaction of the AHR with specific hyperoxic respopressing the hCYP1A1 in a lung-spcific manner will be less susceptible to hyperoxic lung injury than similarly exposed WT mice. The proposed studies should provide conceptual foundation(s) for the development of novel rational strategies for the prevention and treatment of BPD and other diseases in preterm and term infants. PUBLIC HEALTH RELEVANCE: Supplemental oxygen is used extensively in the treatment of pulmonary insufficiency in infants. In premature infants, hyperoxic therapies contribute to the development of bronchopulmonary dysplasia (BPD) and other multi-organ failures. Using knockout and transgenic mice, and cell culture models, this project is aimed at developing novel approaches for the prevention and treatment of lung (e.g., BPD) and other diseases associated with hyperoxia.