An ovary-on-a-chip to identify ovarian toxicity

PROJECT SUMMARY The ovary and its functional unit, the follicles, are critical for the secretion of sex steroids and peptide hormones as well as the maturation and release of oocytes for ovulation and fertilization. Increasing evidence has revealed that a wide spectrum of environmental chemicals and pharmaceuticals cause ovarian toxicity (ovotoxicity) and heighten the risk of premature ovarian failure, hormonal imbalance, and infertility in both reproductive aged women and prepubertal girls. With over 85,000 chemicals used in consumer products as well as emerging contaminants such as harmful algal bloom (HAB) toxins, there are few means to screen for potential toxicity to the ovaries. We have previously developed an ovary-on-a-chip (OvaryChip) that maintains the 3D architecture of follicles and produces human menstrual cycle-like follicle development, hormone secretion, oocyte maturation, ovulation, and luteinization. Yet, one remaining challenge of this innovative model is the critical need to accelerate throughput. The central hypothesis of this research is that in vitro microfluidic follicular cultures can be used to identify novel mechanisms of ovarian toxicity for environmental toxicants. In Aim 1, we will integrate follicle vitrification, 3D in vitro follicle growth, and a new OvaryChip with high-content culture and imaging to develop a high-throughput ovotoxicity testing of growing follicles. In Aim 2, we will develop a new OvaryChip for ovotoxicity testing of primordial follicles by using triple transgenic mouse ovarian explants. In Aim 3, we will develop a liver-ovary-on-a-chip to incorporate liver metabolism into ovotoxicity testing. In these studies, we will assess follicle and oocyte reproductive outcomes at morphological, functional, and molecular levels for 1) chemicals with known ovotoxicities (validation studies) and 2) novel HAB toxins alone and in mixtures. These studies are critically significant because the OvaryChip models will (1) translate a bench assay for a single compound into a robust high-throughput ovotoxicity screening platform; (2) reveal novel insight into chemical- induced ovotoxicity (stage- and metabolite-dependent mechanisms); (3) minimize the cost and use of whole animals; and (4) prioritize chemicals of high ovotoxicity concern, including HAB toxins, for further risk assessment.