# Project 1 - TBD > **NIH NIH P20** · UNIVERSITY OF MISSISSIPPI MED CTR · 2024 · $216,646 ## Abstract Abstract/Summary Estradiol (17βE), the primary female sex hormone used as supplementation therapy in post-menopausal aged women fails to improve cognitive function and is well known to increase the risk of stroke (ischemic reperfusion (IR) injury). Therefore, it is essential to understand cerebral vascular mechanisms in post-menopausal conditions to identify 17βE pathways that do not have adverse effects. Cerebral vessels exhibit myogenic reactivity, a property in which vessels contract with an increase in lumen pressure to maintain a constant CBF. This essential physiological function is mediated by the dynamic regulation of Ca2+-sensitive large-conductance K+ ion channel (BK). While BKα-subunit forms a pore, β1-subunit regulates BK channel function. Loss of BKβ1- subunit function exaggerates myogenic response and vice versa. Recently, studies from our lab suggest that middle cerebral arteries (MCA) isolated from ovariectomized (OVX) rats exhibit exaggerated myogenic reactivity and decreased vasodilation due to the downregulation of BKβ1-subunit. However, the mechanism contributing to BKβ1 downregulation is not known, nor is the exact role of 17βE-mediated regulation of BKβ1. While the mechanism is suspected to occur via the Nrf2 (transcription factor) antioxidant pathway, more mechanistic study is needed. Based on this gap in knowledge, the central hypothesis is that “a decrease in 17βE-Nrf2- mediated transcriptome downregulates BKβ1-mediated vasodilation which increases susceptibility to ischemic reperfusion injury and results in vascular cognitive impairment.” Preliminary studies have shown that pharmacological inhibition and genetic deletion of Nrf2 in knock out (KO) rats disrupted 17βE-mediated up-regulation of BKβ1 and pharmacological activation of Nrf2 improved cognitive function in OVX rats. Nrf2KO rats also showed greater ischemic reperfusion (IR) induced infarct compared to control rats. Therefore, in aim 1, we will test the hypothesis that "the Nrf2 antioxidant pathway plays a role in BKβ1 vasodilation". In aim 2, we will test the hypothesis that “loss of 17βE downregulates Nrf2, decreases BKβ1-mediated vasodilation resulting in cognitive impairment”. Finally, aim 3, we will test the hypothesis that “loss of 17βE-Nrf2-BKβ1-mediated vasodilation exaggerates IR injury”. Together these studies will identify therapeutic targets to improve cognitive function in post-menopausal aged women and identify vascular mechanisms involved in cognitive impairment. The expertise and resources offered through the MCHD-COBRE will allow for a systematic evaluation of the Nrf2-BKβ1 pathway through acquiring genomic datasets, development and study of gene-edited cell-lines for mechanistic study of Nrf2, and validation through targeted proteomic analysis, to ultimately provide a molecular to whole animal understanding of the 17βE-Nrf2-BKβ1-pathway in vascular function. ## Key facts - **NIH application ID:** 10802289 - **Project number:** 5P20GM144041-02 - **Recipient organization:** UNIVERSITY OF MISSISSIPPI MED CTR - **Principal Investigator:** MICHAEL R GARRETT - **Activity code:** P20 (R01, R21, SBIR, etc.) - **Funding institute:** NIH - **Fiscal year:** 2024 - **Award amount:** $216,646 - **Award type:** 5 - **Project period:** 2023-03-06 → 2028-02-29 ## Primary source NIH RePORTER: https://reporter.nih.gov/project-details/10802289 ## Citation > US National Institutes of Health, RePORTER application 10802289, Project 1 - TBD (5P20GM144041-02). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10802289. Licensed CC0. --- *[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*