Biology subjects

Klein, W. L.

Publications and source records attributed to Klein, W. L..

3 recordsLinked to original sources

bioRxiv2022

AAV-mediated neuronal expression of a scFv antibody selective for Aβ oligomers protects synapses and rescues memory in Alzheimer models

Brain accumulation of soluble oligomers of the amyloid-{beta} peptide (A{beta}Os) has been implicated in synapse failure and memory impairment in Alzheimers disease. Here, we show that treatment with NUsc1, a single-chain variable fragment antibody (scFv) that selectively targets A{beta}Os, prevents the inhibition of long-term potentiation in hippocampal slices and memory impairment induced by A{beta}Os in mice. As a therapeutic approach for intracerebral antibody delivery, we developed an adeno-associated virus vector to drive neuronal expression of NUsc1 (AAV-NUsc1) within the brain. Transduction by AAV-NUsc1 induced NUsc1 expression and secretion in adult human brain slices, and inhibited A{beta}O binding to neurons and A{beta}O-induced loss of dendritic spine loss in primary rat hippocampal cultures. Treatment of mice with AAV-NUsc1 prevented memory impairment induced by A{beta}Os and, importantly, reversed memory deficits in aged APPswe/PS1{Delta}E9 Alzheimers disease model mice. These results support the feasibility of gene-mediated immunotherapy using single-chain antibodies as a potential therapeutic approach in Alzheimers disease.

neuroscience↗

bioRxiv2021

Amyloid β oligomer selective antibodies for Alzheimers therapeutics and diagnostics

Improvements have been made in the diagnosis of Alzheimers disease (AD), manifesting mostly in the development of in vivo imaging methods that allow for the detection of pathological changes in AD by MRI and PET scans. Many of these imaging methods, however, use agents that probe amyloid fibrils and plaques - species that do not correlate well with disease progression and are not present at the earliest stages of the disease. Amyloid {beta} oligomers (A{beta}Os), rather, are now widely accepted as the A{beta} species most germane to AD onset and progression. Here we report evidence further supporting the role of A{beta}Os as pathological instigators of AD and introduce promising anti-A{beta}O diagnostic probes capable of distinguishing the 5xFAD mouse model from wild type mice by PET and MRI. In a developmental study, A{beta} oligomers in 5xFAD mice were found to appear at 3 months of age, just prior to the onset of memory dysfunction, and spread as memory worsened. The increase of A{beta}Os is prominent in the subiculum and correlates with concomitant development of reactive astrocytosis. The impact of these A{beta}Os on memory is in harmony with findings that intraventricular injection of synthetic A{beta}Os into wild type mice induced hippocampal dependent memory dysfunction within 24 hours. Compelling support for the conclusion that endogenous A{beta}Os cause memory loss was found in experiments showing that intranasal inoculation of A{beta}O-selective antibodies into 5xFAD mice completely restored memory function, measured 30-40 days post-inoculation. These antibodies, which were modified to give MRI and PET imaging probes, were able to distinguish 5xFAD mice from wild type littermates. These results provide strong support for the role of A{beta}Os in instigating memory loss and salient AD neuropathology, and they demonstrate that A{beta}O selective antibodies have potential both for therapeutics and for diagnostics.

neuroscience↗

bioRxiv2020

Identification of amyloid beta oligomers in locus coeruleus (LC) neurons of Alzheimer's patients and their impact on LC oxidative stress, inhibitory neurotransmitter receptors and neuronal excitability

Amyloid {beta} oligomers (A{beta}O) are potent modulators of two key Alzheimers pathological processes, namely synaptic dysfunction and tau tangle formation in various brain regions. Remarkably, the impact of A{beta}O in one of the earliest brain regions to exhibit Alzheimers pathology, the locus coeruleus (LC), remains to be determined. Of particular importance is the effect of A{beta}O on the excitability of individual LC neurons. This parameter determines brain-wide noradrenaline (NA) release, and thus NA-mediated brain functions, including cognition, emotion and immune function, which are all severely compromised in Alzheimers. Using a mouse model of increased A{beta} production (APP-PSEN1), together with correlative histopathological analyses in post mortem Alzheimers patient samples, we determined the impact of A{beta} pathology on various correlates of LC neuronal integrity. A{beta}O immunoreactivity in the LC of APP-PSEN1 mice was replicated in patient samples, presenting as individual clusters located both intraneuronally, in mitochondrial compartments, as well as extracellularly in association with inhibitory synapses. No specific signal was detected in either patient control or wild type mouse samples. Accompanying this A{beta}O expression profile was LC neuronal hyperexcitability and indicators of oxidative stress in APP-PSEN1 mice. LC hyperexcitability arose from a diminished inhibitory effect of GABA, due to impaired expression and function of the GABA-A receptor (GABAAR) 3 subunit. Importantly, this altered LC 3-GABAAR expression profile overlapped with A{beta}O expression in both APP-PSEN1 mice and Alzheimers patient samples. Finally, strychnine-sensitive glycine receptors (GlyRs) remained resilient to A{beta}O-induced changes and their activation reversed LC hyperexcitability. Alongside this first demonstration of A{beta}O expression in the LC of Alzheimers patients, the study is also first to reveal a direct association between A{beta}O and LC neuronal excitability. GlyR-3-GABAAR modulation of A{beta}O-dependent LC hyperexcitability could delay the onset of cognitive and psychiatric symptoms arising from LC-NA deficits, thereby significantly diminishing the disease burden for Alzheimers patients.

neuroscience↗