The experiments in this project use innovative gene delivery techniques and a multipronged approach to assess the fundamental role of astrocyte activation in neurologic function in an intact mouse model of Alzheimer's disease (AD). Studies use adeno-associated virus vectors (AAV) bearing the astrocyte-specific promoter Gfa2 to target the protein phosphatase calcineurin (CN) and NFAT transcription factors in astrocytes of wild-type and APP/PS1 mice. AAV-Gfa2 vectors are bilaterally delivered to the hippocampus at different ages/disease stages and mice are assessed on different AD biomarkers.
In Aim 1, cognitive status is assessed using the active avoidance task, while synaptic function is evaluated using hippocampal slice electrophysiology and Western blot measures of synaptic proteins.
In Aim 2, hippocampal glutamate regulation is investigated using ceramic enzyme-based microelectrode arrays and measures of glutamate transporter levels.
In Aim 3, levels of glial activation and neuroinflammation are determined with immunohistochemical (IHC) analyses and assessment of cytokine levels using Multiplex ELISAs.
In Aim 4, IHC is used to determine the extent of A? deposition, while ELISAs are used to quantify levels of A?40 and A?42 in soluble and insoluble hippocampal tissue fractions, and Westerns used to assess BACE protein expression. AAV-Gfa2 vectors encode either potent inhibitors or activators of CN/NFAT signaling and therefore will determine the necessity and sufficiency of this astrocytic pathway in driving and/or maintaining neurologic dysfunction in AD mice. These studies provide a highly novel approach to the study of activated astrocytes and could have a major impact on the development of treatment strategies for AD and other neurodegenerative conditions.
Increasing evidence implicates activated astrocytes in a variety of neurodegenerative conditions, including Alzheimer's disease (AD). However, these cells are difficult to target selectively with therapeutics. In this project, we use cutting-edge adeno associated virus vectors to selectively prevent astrocyte activation and improve neurologic function in intact AD model mice. This approach could emerge as a new treatment strategy for AD and other neurodegenerative disorders.
|Norris, Christopher M (2018) Calcineurin: directing the damage in Alzheimer disease: An Editorial for 'Neuronal calcineurin transcriptional targets parallel changes observed in Alzheimer disease brain' on page 24. J Neurochem 147:8-11|
|Kraner, Susan D; Norris, Christopher M (2018) Astrocyte Activation and the Calcineurin/NFAT Pathway in Cerebrovascular Disease. Front Aging Neurosci 10:287|
|Castonguay, David; Dufort-Gervais, Julien; Ménard, Caroline et al. (2018) The Tyrosine Phosphatase STEP Is Involved in Age-Related Memory Decline. Curr Biol 28:1079-1089.e4|
|Price, Brittani R; Norris, Christopher M; Sompol, Pradoldej et al. (2018) An emerging role of astrocytes in vascular contributions to cognitive impairment and dementia. J Neurochem 144:644-650|
|Sompol, Pradoldej; Norris, Christopher M (2018) Ca2+, Astrocyte Activation and Calcineurin/NFAT Signaling in Age-Related Neurodegenerative Diseases. Front Aging Neurosci 10:199|
|Sompol, Pradoldej; Furman, Jennifer L; Pleiss, Melanie M et al. (2017) Calcineurin/NFAT Signaling in Activated Astrocytes Drives Network Hyperexcitability in A?-Bearing Mice. J Neurosci 37:6132-6148|
|Pettigrew, L Creed; Kryscio, Richard J; Norris, Christopher M (2016) The TNF?-Transgenic Rat: Hippocampal Synaptic Integrity, Cognition, Function, and Post-Ischemic Cell Loss. PLoS One 11:e0154721|
|Norris, Christopher M; Sompol, Pradoldej; Roberts, Kelly N et al. (2016) Pycnogenol protects CA3-CA1 synaptic function in a rat model of traumatic brain injury. Exp Neurol 276:5-12|
|Lovell, Mark A; Lynn, Bert C; Fister, Shuling et al. (2016) A Novel Small Molecule Modulator of Amyloid Pathology. J Alzheimers Dis 53:273-87|
|Furman, Jennifer L; Sompol, Pradoldej; Kraner, Susan D et al. (2016) Blockade of Astrocytic Calcineurin/NFAT Signaling Helps to Normalize Hippocampal Synaptic Function and Plasticity in a Rat Model of Traumatic Brain Injury. J Neurosci 36:1502-15|
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