Publications by authors named "Berkley A Lynch"

[C]UCB-J is a PET radioligand that binds to the presynaptic vesicle glycoprotein 2A. Therefore, [C]UCB-J PET may serve as an in vivo marker of synaptic integrity. The main objective of this study was to evaluate the quantitative accuracy and the 28-day test-retest repeatability (TRT) of various parametric quantitative methods for dynamic [C]UCB-J studies in Alzheimer's disease (AD) patients and healthy controls (HC).

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[C]UCB-J is a novel radioligand that binds to synaptic vesicle glycoprotein 2A (SV2A). The main objective of this study was to determine the 28-day test-retest repeatability (TRT) of quantitative [C]UCB-J brain positron emission tomography (PET) imaging in Alzheimer's disease (AD) patients and healthy controls (HCs). Nine HCs and eight AD patients underwent two 60 min dynamic [C]UCB-J PET scans with arterial sampling with an interval of 28 days.

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Synaptic dysfunction is a pathological feature in many neurodegenerative disorders, including Alzheimer's disease, and synaptic loss correlates closely with cognitive decline. Histone deacetylases (HDACs) are involved in chromatin remodeling and gene expression and have been shown to regulate synaptogenesis and synaptic plasticity, thus providing an attractive drug discovery target for promoting synaptic growth and function. To date, HDAC inhibitor compounds with prosynaptic effects are plagued by known HDAC dose-limiting hematological toxicities, precluding their application to treating chronic neurologic conditions.

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LEV (levetiracetam), an antiepileptic drug which possesses a unique profile in animal models of seizure and epilepsy, has as its unique binding site in brain, SV2A (synaptic vesicle protein 2A). Previous studies have used a chimaeric and site-specific mutagenesis approach to identify three residues in the putative tenth transmembrane helix of SV2A that, when mutated, alter binding of LEV and related racetam derivatives to SV2A. In the present paper, we report a combined modelling and mutagenesis study that successfully identifies another 11 residues in SV2A that appear to be involved in ligand binding.

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Article Synopsis
  • The study investigates the structural characteristics of the synaptic vesicle protein 2A (SV2A), which is important for the anti-epileptic drug levetiracetam (LEV), using Protein Tomography on mouse brain tissue.
  • Two main shapes of SV2A were identified: a compact funnel with a pore-like opening and a V-shaped structure with a cleft, indicating the protein's high flexibility and potential valve-like function.
  • The findings suggest that LEV binding does not significantly change the SV2A structure, and the research provides new structural insights that support its function as a transporter, similar to other known transporter proteins.
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Here, we show that the synaptic vesicle protein SV2A is the brain binding site of levetiracetam (LEV), a new antiepileptic drug with a unique activity profile in animal models of seizure and epilepsy. The LEV-binding site is enriched in synaptic vesicles, and photoaffinity labeling of purified synaptic vesicles confirms that it has an apparent molecular mass of approximately 90 kDa. Brain membranes and purified synaptic vesicles from mice lacking SV2A do not bind a tritiated LEV derivative, indicating that SV2A is necessary for LEV binding.

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Gene expression profiling by microarrays is a powerful tool for identification of genes that may encode key proteins involved in molecular mechanisms underlying epileptogenesis. Using the Affymetrix oligonucleotide microarray, we have surveyed the expression levels of more than 26,000 genes and expressed sequence tags (ESTs) in the amygdala-kindling model of temporal lobe epilepsy. Furthermore, the effect of the antiepileptic drug levetiracetam (LEV) on kindling-induced alterations of gene expression was studied.

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