Amniotic fluid entrains embryo-wide branching morphogenesis

Amniotic fluid surrounds the embryo during development. Maintaining proper levels of amniotic fluid during pregnancy is critical for fetal development, particularly for the lung. A reduction in the level of amniotic fluid, also known as oligohydramnios, is associated with pulmonary hypoplasia. Human studies have indicated in cases of low amniotic fluid levels, pulmonary hypoplasia is the strongest predictor of fetal death. Pulmonary hypoplasia often co-presents with hypoplasia of other branched organs, but it is unknown whether the levels of amniotic fluid directly affect their rates of branching morphogenesis. Further, it is unknown whether branching morphogenesis is coupled across the embryo. Here, I propose to test the hypothesis that amniotic fluid pressure or composition couples the rate of branching morphogenesis in organs across the embryo. I will test this hypothesis by taking advantage of the observation that different mouse strains display different gestational lengths, which my preliminary data show are inversely correlated to rate of development. In Aim 1, I will use quantitative imaging analysis to compare the rates of branching morphogenesis in the lung, kidney, and salivary gland (E10-E16) across four strains of mice, normalizing for chronological and morphological ages. In parallel, I will measure the levels and physical properties (volume, osmotic pressure, viscosity) of amniotic fluid over developmental time in each strain. In Aim 2, I will directly test the effects of pressure on the rate of branching by culturing lungs, kidneys, and salivary glands from each strain in an innovative microfluidic culture system to control luminal pressure. Additionally, I will perform mismatched pregnancy experiments in mice, implanting embryos from short and long gestation mouse strains to evaluate the influence of maternal- contributed amniotic fluid to the rate of development. In Aim 3, I will assess potential role(s) for three specific morphogens (SHH, TGF-a, FGF8) in transducing mechanical force to influence the rate of branching morphogenesis. Completion of the aims in this proposal will not only further our understanding of amniotic fluid forces during embryonic development but also lay the groundwork for novel therapeutic strategies to mitigate developmental disorders linked to amniotic fluid imbalances. This proposal will be completed in Dr. Celeste Nelson’s laboratory at Princeton University, a top-tier research institute with state-of-the-art research facilities and exceptional training opportunities. Dr. Nelson has extensive experience in mentoring postdoctoral associates, and her lab offers an ideal environment to achieve the scientific goals outlined in this proposal. During this project, I will enhance my written and oral communication skills, gain experience in teaching and mentoring students, and further develop as a scientist. Additionally, accomplishing these aims will expand my research expertise in mechanobiology and bioengineering. Project Number: 1F32HD120006-01 | Fiscal Year: 2025 | NIH Institute/Center: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) | Principal Investigator: Bridget Waas | Institution: PRINCETON UNIVERSITY, Princeton, NJ | Award Amount: $78,052 | Activity Code: F32 | Study Section: Special Emphasis Panel[ZRG1 F06-F (20)] View on NIH RePORTER: https://reporter.nih.gov/project-details/1F32HD12000601