BLRD Research Career Scientist Award Application

Project Summary/Abstract The overarching goal of Dr. Freeman’s research has been to understand how alterations of the genome/epigenome contribute to aging and how therapies could potentially target these changes to maintain a ‘youthful’ epigenome that retards aging, delays/prevents age-related diseases, and improves the health and

quality of life of the elderly. Epigenetic dysregulation is a hallmark of aging, but exactly how this contributes to cellular dysfunction and disease is not known. To elucidate this contribution, Dr. Freeman’s VA research has focused on epigenomic regulation in astrocytes, microglia, and neurons in the hippocampus with aging. Using

novel cell isolation and advanced sequencing approaches, cell-type specific base resolution maps of both methylation (mC) and hydroxymethylation (hmC) in CG and non-CG contexts are being generated. With paired RNA expression data, bioinformatic techniques are being used to understand the regulation of gene expression

with aging. This type of base-specific, genome-wide, and cell-type specific studies have not been performed in aging research and will potentially offer the most in-depth view of epigenomic changes with aging to date. Further, to demonstrate the prevention of age-related epigenomic changes, caloric restriction is being used. In

total, these studies will not only increase the understanding of the neuroepigenomics of aging but also provide targets for future interventional studies using epigenome editing. Importantly these studies examine both males and females to provide sex-informed insight as his prior studies have demonstrated that the majority of age-

related epigenomic changes are sexually divergent. Dr. Freeman is also PI or co-PI on three NIH projects and one foundation funded project. These studies extend his VA research in aging through use of novel transgenic mouse models and anti-aging interventions in the brain, retina, and GI system. These models developed by his lab allow temporally controlled, cell-type specific tagging

of nuclei and ribosomes to isolate DNA for epigenomic analysis and RNA for expression analysis without the need for cell sorting. In the brain and retina, heterochronic plasma transfer, in which plasma from young mice is administered to old mice for rejuvenation, is being used to determine if age-related epigenomic changes can be

reversed after they have occurred. In parallel, using proteomic approaches, DNMT and TET interacting proteins are being identified that target them to specific genomic regions for epigenomic alteration. More broadly, Dr. Freeman also has an extensive collaborative portfolio with other OKC VAMC investigators. In

these VA and NIH funded studies, Dr. Freeman is examining cell-type specific mechanisms of aging in muscle, brain, ovary, joints, and colon. In addition to bringing molecular and biochemical expertise to these studies, a common thread of epigenetics of aging allows comparisons and contrasts to be made across the organ systems.

These collaborations are paired with his work as Director of the Genomics Sciences Core of a recently renewed P30 NIA Center grant: the Oklahoma Nathan Shock Aging Center. This core provides epigenomic and transcriptomic analyses as well as mitochondrial genomic assays for aging researchers across the country.

Additionally, Dr. Freeman leads many cross-institution (OMRF, OUHSC) initiatives focused on trainee and faculty development, including training students and post-docs (F-Troop) and junior faculty (NeuroGrant Seekers) in successful preparation and submission of grants. He has also worked with leaders at the OKC VAMC to help

recruit new, highly successful investigators to the VA system, one of which has received a MERIT award with three more investigators having MERIT applications currently under review.