Improving egg quality through an engineered biomimetic follicular microenvironment - PROJECT SUMMARY The follicle is the functional unit of the ovary composed of an oocyte surrounded by somatic support cells, including granulosa and theca cells. During folliculogenesis, bi-directional communication between the oocyte and the granulosa cells s accumulation of maternal RNAs, proteins, organelles, and other factors that sustain early developmental events prior to zygotic genome activation, including meiotic maturation, fertilization, and early preimplantation embryo development. Thus, folliculogenesis is an essential process. Over the past several decades, the development of ex vivo ovarian follicle culture techniques has provided a tightly controlled model system to study follicle-intrinsic processes independent of the ovarian microenvironment. There are many successful culture techniques, and one of the most frequently used methods across species involves encapsulation of follicles in alginate-based hydrogels which mimics the three-dimensional architecture of the follicle. These culture methods have revealed key details about the hormonal, molecular, and biomechanical factors important for folliculogenesis and ovulation. Despite these advancements, existing approaches of ex vivo follicle culture are technically demanding and are low throughput. One of the most critical challenges is that these systems produce a consistently low yield of high-quality eggs capable of supporting preimplantation embryo development. In this application, we will engineer a scaffold-free platform that better mimics ovarian biology with the aim to improve the developmental competence of the resulting gamete following ex vivo follicle culture. Through two specific aims, we will integrate and leverage a tunable agarose microwell design, timelapse imaging, and microfluidic culture to develop a follicle culture system capable of producing high-quality gametes. First, we will identify the ideal conditions for culture of high-quality follicles by engineering agarose molds that impart different biomechanical properties on the growing follicle and hone the timing of ovulation using growth parameters of individual follicles based on timelapse imaging. Second, we will use a microphysiological system to determine the effect of dynamic exchanges of fresh and conditioned media that better mimics in vivo nutrient delivery, hormone fluctuations, and waste disposal. The primary endpoints of the study will focus on the quality of the resulting eggs assessed by their ability to yield high-quality preimplantation embryos, which will be monitored by the Embryoscope™ time-lapse system. Our aims merge reproductive biology with innovative bioengineering techniques, which is an essential partnership for developing a biomimetic follicle culture platform that supports maximal egg and embryo quality. This research is expected to create a scalable and accessible tool for basic ovarian biology research and represents a necessary first step towards the clinical translation of this method in the context of fertility preservation.
