Molecular female reproductive tract determinants of sperm function and fertility

SUMMARY After mating, sperm participate in diverse interactions with the female reproductive tract (FRT) that contribute to fertility. The molecular basis of these sperm-female interactions (SFIs) is not well understood, even though they have the potential to be critical in vivo determinants of sperm function and fate. Our long-term goal is to comprehensively characterize the network of molecular SFIs required for fertility and to elucidate fundamental SFI mechanisms. Our central hypothesis is that female-derived metabolic proteins participate in spatiotemporally regulated interactions with sperm and contribute to sperm motility and viability during storage and, in turn, fertilization competency. The rationale is that SFIs are challenging to study in vivo in mammals and we are poised to leverage the highly developed Drosophila research system outlined in this proposal to study processes mediated by SFIs. The central hypothesis will be tested through the following experimental objectives. First, fertility-related functions of FRT metabolic proteins that associate with sperm will be characterized through systematic assays of knockout or knockdown flies for parameters of sperm function and fertility. Second, in vivo spatiotemporal association of female proteins with sperm will be characterized using high-resolution microscopy, and the contribution of FRT-derived exosomes to these interactions will be determined. Third, in vivo metabolomic dynamics of sperm during transit and storage in the FRT will be characterized, for the first time, using quantitative targeted metabolomics. Fourth, mechanisms by which females influence sperm metabolism will be determined experimentally in females lacking FRT secretory tissues, exosome biogenesis or both. Our proposal is innovative because it leverages our unique and new knowledge of female molecules that participate in SFIs to test specific functional hypotheses relating to in vivo mechanisms that govern variation in fertility. Expected outcomes of the proposed research include systematic characterization of (1) the impact of female metabolic proteins on sperm function and fertility, and (2) the contribution of the FRT to in vivo sperm metabolome dynamics. The results will have a significant and immediate positive impact by advancing the mechanistic understanding of SFIs. In the long-term, they will provide the foundation for translational research into novel contraceptives and treatments to remediate infertility. Project Number: 1R01HD117926-01A1 | Fiscal Year: 2026 | NIH Institute/Center: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) | Principal Investigator: Stephen Dorus | Institution: SYRACUSE UNIVERSITY, SYRACUSE, NY | Award Amount: $323,643 | Activity Code: R01 | Study Section: Cellular, Molecular and Integrative Reproduction Study Section[CMIR] View on NIH RePORTER: https://reporter.nih.gov/project-details/11365651