Effects of leptin and its Mechanisms of Action on Mammalian Trophoblast Cells

了解成功妊娠的关键是确定胎盘如何附着在母体子宫壁上。胎盘的外层含有一层细胞（滋养层），它具有侵入子宫内膜的能力，从而形成胎盘。入侵过程是如何启动和调节的尚不确定。在这个项目中，假设生殖激素瘦素刺激滋养层细胞的侵袭性，将在人造蛋白质包被膜上生长的滋养层细胞中进行研究。侵入性细胞分泌降解蛋白质涂层的酶，并允许细胞穿过膜上的小孔;在显微镜下计数穿透膜的细胞数量。瘦素刺激胎盘滋养层细胞在妊娠早期和晚期侵袭的能力将被检测;我们预测瘦素只会促进早期胎盘滋养层细胞的侵袭。瘦素刺激侵袭性的分子机制将通过检测瘦素诱导的细胞内信号分子和基因表达的变化来确定。胎盘将在代表两个最丰富的哺乳动物目的物种中进行研究。小鼠胎盘不产生瘦素，但表达瘦素受体，因此对瘦素作用敏感。小棕蝙蝠的胎盘产生并分泌瘦素（人类胎盘也是），和老鼠一样，胎盘也是瘦素的目标。瘦素对小鼠和蝙蝠胎盘功能的影响有待进一步研究。该项目更广泛的影响包括：1）证明瘦素在不同哺乳动物中建立胎盘的重要性; 2）了解瘦素作为细胞迁移和入侵的一般信号的作用（即，在已知瘦素起作用和细胞具有侵袭性的其他细胞类型中）; 3）了解激素对滋养层细胞的妊娠阶段依赖性作用;以及4）教育年轻的在职科学家和推广活动，包括代表性不足的少数群体的参与（每年将在该项目上指导一名博士后研究员、一到两名研究生和四名本科生）。

Central to an understanding of successful pregnancies is determining how the placentaattaches itself to the uterine wall of the mother. The outer lining of the placenta contains a layerof cells (trophoblasts), which have the property of being able to invade the uterine lining, thusestablishing the placenta. How the invasion process is initiated and regulated is uncertain. Inthis project, the hypothesis that the reproductive hormone leptin stimulates invasiveness oftrophoblast cells will be investigated in trophoblast cells grown on an artificial, protein-coatedmembrane. Invasive cells secrete enzymes that degrade the protein coating, and permit the cellsto move through tiny pores in the membrane; the number of cells penetrating the membrane arecounted under a microscope. The ability of leptin to stimulate invasion of trophoblasts fromplacentas at early and late gestation will be examined; we predict that leptin will promoteinvasion only in trophoblasts from early-stage placentas. The molecular mechanisms by whichleptin stimulates invasiveness will be determined by examining changes in intracellular signalingmolecules and gene expression induced by leptin. Placentas will be studied in speciesrepresenting the two most abundant mammalian orders. The mouse placenta does not produceleptin, but expresses receptors for leptin and is therefore sensitive to leptin actions. The littlebrown bat placenta produces and secretes leptin (as does the human placenta), and like the mouseplacenta is a target for leptin. The effects of leptin on mouse and bat placental function will becompared. Broader impacts of this project include: 1) documentation of the importance of leptinin establishing the placenta in diverse mammals; 2) understanding the role of leptin as a generalsignal for cell migration and invasion (i.e., in other cell types where leptin is known to act andwhere cells are invasive); 3) understanding gestational stage-dependent actions of hormones ontrophoblast cells; and 4) education of young scientists-in-training and outreach to includeparticipation of underrepresented minorities (one postdoctoral fellow, one to two graduatestudents and four undergraduates students will be mentored per year on this project).