COBRE: UNE MED CTR: P3: ETHANOL-RETINOID INTERATION IN INNER EAR MALFORMATIONS

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。正如最初提议的那样，该项目涉及使用分子遗传学方法，从机制上关注产前酒精暴露（胎儿酒精综合征）后导致内耳畸形的发育事件的改变。流行病学证据表明，大约30%的FAS患儿经历感音神经性听力损失，但其潜在机制在很大程度上尚不清楚。据推测，子宫内酒精暴露后内耳/耳蜗畸形是由于酒精和视黄醇在酒精脱氢酶途径上的竞争导致内源性维甲酸生物合成减少所致。这一假设得到了使用具有RARE-lacZ结构的F9细胞系的体外实验的证实，其中？-半乳糖苷酶染色（视黄酸反应元件（RARE）激活阳性）随着培养基中添加浓度的增加而得到证实。对近交系SWV小鼠母鼠进行乙醇处理后，其后代出现了多种出生缺陷，包括畸形、面中发育不全、唇腭裂、心脏缺陷和尾侧退化，而这些缺陷在给小鼠喂食富含维生素a的食物后都得到了预防。在小鼠和鸡胚模型中研究了乙醇暴露对内耳形态的影响。然而，母体酒精暴露的致畸作用被认为是非常多效的，该项目重新集中在涉及神经感觉系统的单一基因/途径上。新提案将研究在视网膜色素上皮（RPE）和内耳血管纹发育中由小眼相关转录因子（Mitf）调控的遗传/生化途径。这将包括Mift在RPE和纹中决定细胞命运的功能，它对内皮生长因子的反应，以及它在调节氧化应激中的作用。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The project, as initially proposed, involves using a molecular genetic approach to focus mechanistically on alterations in developmental events leading to malformations of the inner ear subsequent to prenatal alcohol exposure (Fetal Alcohol Syndrome; FAS). Epidemiological evidence suggests that approximately 30% of children affected with FAS experience sensorineural hearing loss, yet the underlying mechanisms are largely unknown. It was hypothesized that malformations of the inner ear/cochlea following in utero alcohol exposure resulted from a decrease in endogenous retinoic acid biosynthesis due to competition between alcohol and retinol for alcohol dehydrogenase enzyme pathways. This hypothesis was substantiated by in vitro experiments using an F9 cell line with a RARE-lacZ construct, in which a decrease in ?-galactosidase staining (positive for activation of the retinoic acid response element (RARE)) was demonstrated as increasing concentrations of ethanol were added to the media. Ethanol administration to pregnant dams of the inbred SWV murine strain resulted in offspring with multiple birth defects, including exencephaly, midfacial hypoplasia, cleft lip/palate, heart defects, and caudal regression, all of which were prevented when the mice were fed a diet rich in vitamin A. The impact of ethanol exposure on inner ear morphology was examined in both murine and chick embryo models. However, the teratogenic effects of maternal alcohol exposure were recognized to be very pleiotropic, and the project has re-focused on a single gene/pathway involved in a neurosensory system. The new proposal will investigate genetic/biochemical pathways regulated by microphthalmia-associated transcription factor (Mitf) in development of the retinal pigment epithelium (RPE) and in the stria vascularis of the inner ear. This will include the function of Mift in cell fate determination in the RPE and stria, its response to endothelial growth factors, and its role in modulating oxidative stress.