Reproductive aging is a major health, personal and societal issue, but ovarian aging has received limited scientific attention, even in large genomic survey projects. Ovarian aging influences diverse health outcomes in women including lifespan, cardiovascular disease, metabolic syndromes, neurodegenerative disorders and various types of cancer. Yet the molecular mechanisms underlying ovarian aging, timing of menopause and inter-organ feedback loops remain elusive. As one of the most dynamic organs in the human body, the ovary undergoes significant remodeling across the entire reproductive period. The dynamic transcriptional regulation of and interactions between oocytes and their surrounding cells during aging remain unknown. The objective of this proposal is to understand the regulatory landscapes underlying the complex interplay among the different cell types in the ovary and to investigate the molecular mechanisms that regulate the remarkably complex processes of reproductive aging. We will apply powerful single-cell (sc) RNA-seq and scATAC-seq analysis to define specific transcriptional programs and regulated enhancer networks that are altered in distinct ovarian cell types or subtypes during aging. By defining the roles of specific enhancers in specific cell types, and how these change with aging, we aim to understand the identities of the regulatory factors and environmental signals that impact aging in each ovarian cell type. Genetic variation affecting enhancer selection and function is a major determinant of differences in cell-specific gene expression between individuals. To investigate the mechanisms by which altered regulatory enhancer landscapes contribute to ovarian aging by licensing changes in transcriptional programs, we will investigate the roles of genetic variants associated with age at menopause, detected by genome-wide association studies (GWAS), in modulating transcription programs during ovarian aging. In particular, we hope to provide mechanistic insights into genetic modulation of transcriptional regulation of critical homeostatic and inflammatory pathological functions in the granulosa cells (GC), the supporting cell type immediately surrounding the oocyte, by modeling the causal regulatory variants in human GC models that are differentiated from human ESCs engineered to carry causal variants by CRISPR gene editing.

There is overwhelming evidence that female reproductive aging influences lifespan and diverse health outcomes. To gain insights into the molecular basis of reproductive aging and its influences in later life health outcomes, we aim to characterize gene regulatory landscapes that are altered in the ovary during aging and that are causally linked to genetic factors influencing age at menopause.