Calcium-mediated mechanisms of metabolic and epigenetic changes at fertilization

The National Institute of Child Health and Human Development awarded East Carolina University $249,000 on September 1, 2026, under the Child Health and Human Development Extramural Research program (CFDA 93.865) to investigate calcium-mediated mechanisms of metabolic and epigenetic changes at fertilization in mammals.

The research uses mouse models to determine how abnormal calcium dynamics at fertilization impact embryonic epigenetic reprogramming and offspring development. The work addresses concerns that assisted reproductive technologies and conditions affecting mitochondrial function—such as obesity or advanced maternal age—can alter intracellular calcium oscillations and compromise embryonic developmental competence and offspring health. The three specific aims examine the impact of excess calcium on global chromatin accessibility and transcription profiles of early embryos, and identify underlying mechanisms mediated by histone-modifying enzymes including CREEBP and SIRT1. The research leverages genetically modified mouse models with altered calcium signaling at fertilization, developed during prior postdoctoral training, to isolate epigenetic changes driven by calcium dynamics without confounding effects of in vitro manipulation. Findings may inform standardization of culture media composition across assisted reproductive technology clinics and inform risk assessment for children conceived through these techniques or born to women with mitochondrial dysfunction.

Performance occurs in North Carolina. The period of performance runs September 1, 2026, through August 31, 2029.

Abstract

In mammals, a new life is initiated by transient changes in the EGG's intracellular calcium (CA2+) level, called CA2+ oscillations. Dynamics of CA2+ oscillations are environmentally responsive and can be altered in vitro by changing the ionic composition of culture media, such as in assisted reproductive technologies (art), or in vivo by conditions affecting mitochondrial function, such as obesity or advanced maternal age. We and others showed that abnormal CA2+ dynamics at fertilization negatively impact mouse embryo developmental competence, and offspring growth and health. These outcomes raise concerns that there could be similar consequences for children of women with dysfunctional mitochondria or conceived by art, where the ionic composition is not standardized and varies enormously among different culture media and different clinics. In preliminary data i found a link between CA2+ dynamics at fertilization and chromatin remodeling in the 1-cell (1C) mouse embryo. IT is urgent to identify how CA2+ impacts the epigenetic reprogramming of the early embryo and helps shape the embryonic developmental program, ultimately affecting offspring growth and health. My overarching goal is to identify mechanisms linking CA2+ homeostasis at fertilization with embryo reprogramming. I will use the mouse model to determine the impact of excess CA2+ on global chromatin accessibility (aim 1) and transcription profile (aim 2) of early embryos and to identify the mechanisms underlying this link, mediated by histone modifying enzymes such as creepb and/or SIRT1 (aim 3). Genetic mouse models with excess CA2+ signals at fertilization (that i developed during my postdoctoral training) will be used to assess epigenetic changes purely associated with CA2+ changes, without influence of in vitro manipulation. Protocols used currently in human art, such as the use of CA2+-ionophore to artificially increase CA2+ levels, will be used to evaluate the impacts of CA2+ changes and in vitro manipulation. Rhesus macaque embryos (aim 2), which are evolutionarily close to human, will be used to strengthen the translatability of my results for their application to human health. Pursuit of these aims requires training in next generation sequencing technologies and big data analysis. Results from this study will identify mechanisms by which CA2+ exposure at fertilization impacts embryo reprogramming and will contribute to raising awareness in clinicians and embryologists of the impact of procedures and culture media composition on preimplantation embryo chromatin reprogramming. Moreover, the results will help address fertility concerns in women facing obesity or advanced maternal age who are trying to conceive. In the long term, these results will lay the basis for my translational research, to improve art protocols and help improve offspring wellbeing. In this regard, my proposal is deeply aligned with nichd mission. This plan, training, and support from the outstanding research advisory team i have assembled will strengthen the academic opportunities available to me and will lay the foundations for a unique niche in which i can develop as an independent researcher and pursue a fruitful career in the reproductive sciences.