Fetal Membrane AQP Expression/Amniotic Fluid Regulation

描述(申请人提供)：羊水(AF)是正常妊娠的必要伴随，是胎儿运动、生长和发育所必需的。羊水过多(羊水过多)或羊水过少(羊水过少)与围产儿发病率显著相关。尽管房颤量非常重要，但对导致房颤量异常的机制缺乏了解(S)。房颤液体的膜内吸收途径(跨羊膜)最近被认为是房颤吸收的关键调节途径，对房颤容量的动态平衡有重要作用。然而，跨羊膜吸收水分的潜在分子和细胞机制仍不清楚。水通道蛋白(Aquaporins，AQPs)是细胞膜上的水通道蛋白，可显著提高细胞膜的通透性。在迄今已鉴定的11种哺乳动物水通道蛋白中，我们的研究检测到3种水通道蛋白(水通道蛋白3、8和9)在人和羊绒毛膜和胎盘中的表达。原位杂交结果显示，AQP8在人羊膜和绒毛上皮细胞以及胎盘滋养层细胞中均有表达。此外，研究人员还证明，AQP8基因在人羊膜上皮细胞系中的表达保持不变，第二信使cAMP上调了羊膜细胞中AQP8基因的表达。根据初步研究，研究人员假设房颤的水吸收是通过绒毛膜上选择的AQP水通道发生的，并受其调节。研究人员建议：1)表征水通道(AQP 3、8和9)在人和绵羊胎膜中的时空表达，并将其变化与绵羊妊娠期间房颤体积动力学的已知变化相关联；2)研究内分泌(催产素、催乳素)和第二信使cAMP对体外培养的人羊膜细胞AQPs基因表达的调节；以及3)体内内分泌和cAMP对上皮细胞AQP基因表达的调节，并确定其对房颤体积的影响。我们的目标是确定胎膜AQP表达的调节机制，并阐明AQP在房颤稳态中的作用。

DESCRIPTION (provided by applicant): Amniotic fluid (AF) is an essential accompaniment of normal pregnancy, necessary for fetal movement, growth and development. Excess (polyhydramnios) or deficient (oligohydramnios) AF volume is associated with significant perinatal morbidity. Despite the critical importance of AF volume, there is a lack of understanding of mechanism(s), which result in AF volume abnormalities. The intramembranous pathway of AF fluid absorption (across the amniotic membrane) has recently been recognized as a critical regulatory path for AF resorption, contributing importantly to AF volume homeostasis. Yet the underlying molecular and cellular mechanisms for water absorption across the amniotic membranes remain unknown. Aquaporins (AQPs) are cell membrane water channel proteins that greatly enhance cell membrane water permeability. Of the 11 mammalian AQPs identified to date, our studies detected the expression of three AQPs (AQP 3, 8 and 9) in human and ovine chorioamniotic membranes and placenta. In situ hybridization reveals that AQP8 is expressed in epithelial cells of human amnion and chorion, as well as trophoblasts of placenta. In addition, the investigators have demonstrated that AQP8 gene expression is maintained in a human amnion epithelial cell line, and AQP8 gene expression in amnion cells is upregulated by second messenger cAMP. In view of preliminary studies, the investigators hypothesize that AF water absorption occurs via, and is regulated by, select AQP water channels in the chorioamniotic membranes. The investigators propose to: 1) Characterize the temporal and spatial expression of water channels (AQP 3, 8 and 9) in both human and ovine fetal membranes, and correlate its change to known changes in AF volume dynamics throughout pregnancy in sheep; 2) Investigate the endocrine (oxytocin, prolactin) and second messenger camp regulation of AQPs gene expression in human amnion cell line in vitro; and 3) Explore endocrine and cAMP regulation of epithelial AQPs gene expression in vivo and determine the effect on AF volume. Our objective is to determine the regulatory mechanisms of fetal membrane AQP expression and delineate the role of AQPs in AF homeostasis.