PROJECT SUMMARY – PROJECT 2 The mission of the Perimenopause in Brain Aging and Alzheimer’s disease (P3) is to discover biological transformations in brain that occur during the perimenopausal transition that lead to endophenotypes predictive of risk for Alzheimer’s disease (AD). Each year ~1.5 million American women enter into the perimenopause, a neuroendocrine transition state unique to the female. Herein, we focus on the neuro-immune system as a key driver of chronological and endocrinological aging that occurs in the midlife female brain. Our goals are to identify the mechanisms by which these transformations occur and to translate these discoveries into strategies to prevent conversion to an at-Alzheimer's-risk phenotype. Project 2 contributes to achieving P3 goals by determining the systems of immune biology activated across midlife chronological and endocrinological aging, the dynamic conversions in immune transcriptome and phenotype, the contributing cells, the map of neural immune responses and therapeutics that specifically target each stage of immune conversion. The overall hypothesis guiding Project 2 program of research is that the immune system is the initiator and driver of the metabolic crisis in brain. Based on our preliminary evidence, we anticipate that the neuro-immune profile in brain will be dynamic and endocrine aging stage dependent. Further, we hypothesize that APOE genotype will be a key regulator of the neuro-immune system of biology in brain. Aim 1 addresses fundamental systems biology of the interface between the bioenergetic and immune systems in brain. Aim 1 analyses will determine the dynamic neuro-immune genotypic/phenotypic signatures that emerge over the course of the pre, peri, and postmenopausal transition. The goal of Aim 2 is to establish a foundation for precision immune modulating therapies for reduction of Alzheimer’s disease risk in women based on endocrine aging status and APOE genotype which will be achieved through computational medical bioinformatics strategies. The translational goal of Aim 3 is to create a platform for precision neuro-immune therapy based on APOE4 genetic burden and endocrine aging status. Aim 3 objectives will be achieved by: 1) integrating neuro-immune signatures derived from Aim 1 with therapeutic candidates from Aim 2; 2) treating hAPOE mice with neuro-immune therapy specific to endocrine aging transition; 3) determining efficacy of precision neuro-immune therapy to prevent, delay and treat hallmark pathologies of Alzheimer’s disease. Collectively, outcomes of these analyses will provide a platform on which to achieve precision neuro-immune medicine to intervene with the right therapy at the right time in the right APOE genotype. Research proposed herein addresses strategic goals of the National Institutes on Aging’s 2016: Aging Well in the 21st Century: Strategic Directions for Research on Aging, specifically Goals A1, 2, 3, 7, 8 & 11 and Goals D1, 2, & 4.