Epigenetic and metabolic mechanisms of environmentally-induced transgenerational germline dysfunction

PROJECT SUMMARY The overarching goal of the research presented in this application is to dissect the genetic, epigenetic, and metabolic programs that encode and transmit a memory of environmental exposure for several generations. In that context, we aim to understand how environmental influences alter the reproductive program of organisms in a transgenerational fashion and what makes the germline a particularly important and sensitive target of exposures. In mammals, in utero ethanol exposure is associated with an array of well-characterized morphological, neurobehavioral, and reproductive issues. However, there is mounting evidence in a variety of model organisms that some adverse reproductive and neurological features are also detectable in the third generation following exposure indicating a transgenerational effect. Alcohol also has a clear epigenetic impact and directly contributes to the modification of the epigenome. Nevertheless, despite the fact that heritable effects of alcohol imply an alteration of the information contained in germ cells, it is unclear how the memory of ethanol exposure is initiated in the germline and then transmitted to future generations. Here, we combine the tractability and conservation of the model system C. elegans with state-of-the-art epigenomic analyses, classical genetic, and cytological approaches to shed light on the mechanisms of memory of ethanol exposure. Our preliminary data shows that ethanol exposure causes strong transgenerational reproductive and behavioral impairments. We also show that, in line with recent mammalian studies, ethanol causes an increase in histone acetylation. Thus, we hypothesize that ethanol exposure causes transgenerational perturbations of germline function by altering the germline epigenome, specifically histone acetylation. Our aims are designed to address the molecular, metabolic and epigenetic requirements for these transgenerational impacts of ethanol. In aim 1, we will build on our preliminary reproduction data to interrogate through classical genetics tools meiotic pathways at the root of ethanol's trans-generational increase in germline apoptosis and embryonic lethality. In aim 2, we will examine via mass spectrometry the modulation in 80 different histone marks stemming from direct ethanol exposure and test whether increased histone acetylation is a required event for the initiation ethanol's transgenerational reproductive effects. Finally, in aim 3, we will test the epigenetic requirement for the transgenerational transmission of ethanol's effects and also map by CUT&RUN the changes in the epigenetic landscape of histone modifications in the germline. At the completion of the aims, we will have identified the molecular underpinnings for the initiation and transmission of ethanol transgenerational reproductive outcomes.