Sunday, May 11, 2025
5/11/2025
Functional deficits in neurovascular coupling in Alzheimer's disease - PROJECT SUMMARY Alzheimer’s disease (AD) is a major public health burden in the United states with a death toll that continues to increase steeply. While cerebral blood flow (CBF) is substantially reduced in AD, the vascular pathophysiology is not yet entirely characterized. We have identified two neurovascular coupling (NVC) mechanisms essential in regulation of CBF: electrical signaling (mediated by K+), which is rapid (millisecond time scale) and acts over long distances, and Ca2+ signaling (mediated by GqPCR agonists), which is slow (seconds) and acts locally. Yet how- these NVC mechanisms are altered in AD is incompletely understood. Therefore, the long-term objective of this proposal is to use a familial mouse model of AD (5xFAD) to determine functional deficit in NVC mechanisms in AD and design therapeutic strategies to restore these impairments. Preliminary data show that electrical signaling is reduced in 5xFAD mice due to impaired Kir2.1 channel function and restored by supplementation of membrane phospholipid; PIP2—an essential component for Kir2.1 channel function. Hence, I have a novel hypothesis that deficit in functional hyperemia in AD is the result of vascular PIP2 depletion, which cripples electrical and Ca2+ signaling control of blood flow. Accordingly, I will determine the molecular mechanisms through which loss of PIP2 disrupts these processes and evaluate whether PIP2 supplementation restores CBF control and in turn, improve cognitive function in 5xFAD mice. I will test this hypothesis by executing the following specific aims: 1) Elucidate mechanisms associated with defective electrical signaling in AD, 2) Evaluate the impact of AD pathology on brain endothelial Ca2+ activity, and 3) Determine the effect of PIP2 restoration on NVC in AD. To execute these specific aims, I will combine of cutting edge in vivo and ex vivo experimental approaches with behavioral testing. Collectively, this proposal will identify vascular functional deficits in AD and PIP2 based therapeutic intervention for restoration of CBF and in turn, cognitive function in AD. This proposal aligns with one of the NIH mission statements to prevent and effectively treat Alzheimer's disease by 2025. This current proposal will contribute Dr. Amreen Mughal’s career development as she transitions from a postdoctoral fellow to an independent researcher. Adding to her strong background in vascular biology, Amreen will develop new skills in the state-of-the-art image analysis and behavioral testing. Dr. Mark T. Nelson, an expert in ion channels, Ca2+ signaling, and vascular biology, will mentor Amreen’s scientific development and transition to independence during this award. To enhance the Candidate’s training, the program additionally enlists a career advisory team, including Drs. Anne Joutel, Sayamwong Hammack, and Severin Schneebeli. The productive research environment with the backing of the NIH Pathway to Independence Award (K99/R00) will allow the Candidate to develop her own research niche and successfully transition as an independent research investigator.
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