Quantifying SEX-specific differences during zebrafish FIN regeneration

Lehigh University received a $155,348 Project Grant from the National Institute of Child Health and Human Development (NICHD) under the Child Health and Human Development Extramural Research program (CFDA 93.865) for the project "Quantifying Sex-Specific Differences During Zebrafish Fin Regeneration." The award, effective August 1, 2025, through July 31, 2027, supports research designed to advance consideration of sex as a biological variable (SABV) in regenerative biology research. The project delivers phenotypic and transcriptomic data analysis by sex during zebrafish fin regeneration, addressing a critical gap identified by the 2016 NIH SABV policy that important biological information may be lost when studies fail to collect and analyze data separately by sex.

The research will generate sex-dependent and sex-independent outcome data through two specific aims focused on revealing sex-dependent phenotypes during fin regeneration and conducting transcriptomic analysis by sex. These deliverables are intended to provide the scientific community with evidence-based guidance on which characteristics of fin regeneration warrant sex-stratified data collection, analysis, and reporting in future studies. The project will be conducted at Lehigh University's Office of Research in Fountain Hill, Pennsylvania, and is expected to inform best practices for incorporating SABV considerations in regenerative biology and developmental research.

Abstract

The zebrafish regenerating FIN is an important model system to understand mechanisms underlying regeneration, skeletal development, and skeletal disease. Although overt phenotypic SEX-differences during FIN regeneration have not been observed, not all sexually dimorphic traits are evident. Thus, the possibility that there are measurable SEX-differences cannot be ruled out. Indeed, one rationale for the 2016 NIH policy to consider SEX as a biological variable (sabv) was that important biological information could be missing from studies that relied on a single SEX, or that ignored SEX when reporting cell/animal data. Importantly, while the inclusion of both sexes is appropriate under the sabv policy, this may not be sufficient over the long-term to reveal the complete biology underlying regeneration. Therefore, the long-term goal of this project is to improve the consideration of sabv for research involving FIN regeneration. The overall objectives for this proposal are to collect, analyze, and report, phenotypic and transcriptomic data by SEX during FIN regeneration. The central hypothesis is that while the majority of experimental studies during zebrafish regeneration includes both sexes, without collecting/analyzing data separately, relevant SEX-dependent differences may be lost. The rationale is that completion of this project will reveal both SEX-dependent and SEX-independent outcomes. In turn, these data will better inform future research by identifying specific characteristics of FIN regeneration better served by collecting/analyzing/reporting data by SEX. The overall objectives will be achieved using two specific aims. The goal of aim 1 is to reveal SEX-dependent phenotypes during FIN regeneration. Fins at different stages of regeneration will be analyzed for differences in commonly measured parameters including total regenerate length, FIN RAY regenerate length, segment length, and cell proliferation. The goal of aim 2 is to reveal SEX- dependent differential gene expression during FIN regeneration. Fins at different stages of regeneration will be analyzed to identify all differentially expressed genes. This proposal is innovative because completion will generate resources that will facilitate the improved application of sabv during FIN regeneration research. This proposal is significant because these resources will drive better informed decisions about collecting/analyzing/reporting data based on SEX, and will therefore positively impact future experimental design.