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Browsing by Author "Fresa, Kyle Joseph, author"

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    Metabolic support of preimplantation embryo growth and viability
    (Colorado State University. Libraries, 2024) Fresa, Kyle Joseph, author; Carnevale, Elaine, advisor; Chicco, Adam, advisor; Tesfaye, Dawit, committee member; Krisher, Rebecca, committee member; Gentile, Christopher, committee member
    Early embryo metabolism involves essential and dynamic biological reactions that support viability, growth, and pregnancy establishment. Embryo metabolism not only serves to provide energy through ATP synthesis, but also facilitates the production of macromolecules such as proteins, nucleotides, and lipids. The ways in which embryos balance catabolic and anabolic activity during the preimplantation stage are not well understood; however, understanding these processes may lead to improved fertility treatments, embryo culture, and pregnancy outcomes. The studies described in this dissertation utilize innovative methods, such as stable isotope tracer analysis to track carbon and nitrogen flux through various pathways, oxygen microsensors to determine individual embryo respiration under various conditions, and proteomic analysis to determine the impacts of metabolic disturbances on embryo viability. The overarching hypothesis of this dissertation is that embryo viability is dependent on efficient and tightly regulated metabolic activity, and disturbances to metabolic function ultimately lead to reduced developmental potential. To test this hypothesis, a series of projects were conducted to 1) evaluate the importance of phosphoenolpyruvate carboxykinase (PEPCK) during early development, 2) uncover the function of PEPCK to support catabolic and anabolic activity in early embryos, and 3) determine the impacts of delayed embryo development on embryo metabolism and pathway regulation. These projects revealed important insights into the impact of embryo metabolism on development, including the discovery of a novel, PEPCK-mediated pathway that embryos utilize to balance energy production and biosynthesis. Furthermore, the impact of delayed embryo development was demonstrated to alter embryo metabolic activity and pathway regulation, including increased aerobic activity and altered protein expression. These findings improve our understanding of metabolic activity and regulation during preimplantation development, highlighting the impact of metabolic activity to promote ATP production, biosynthesis, developmental kinetics, and ultimately survival. The experimental outcomes presented in this dissertation provide a foundation for targeted approaches to improve embryo development and reproductive success.