Functional excitatory to inhibitory synaptic imbalance and loss of cognitive performance in people with Alzheimer’s disease neuropathologic change
Year: 2022
Type: article
Study design: Observational Study
Abstract: Individuals at distinct stages of Alzheimer's disease (AD) show abnormal electroencephalographic activity, which has been linked to network hyperexcitability and cognitive decline. However, whether pro-excitatory changes at the synaptic level are observed in brain areas affected early in AD, and if they are emergent in MCI, is not clearly known. Equally important, it is not known whether global synaptic E/I imbalances correlate with the severity of cognitive impairment in the continuum of AD. Measuring the amplitude of ion currents of human excitatory and inhibitory synaptic receptors microtransplanted from the hippocampus and temporal cortex of cognitively normal, mildly cognitively impaired and AD individuals into surrogate cells, we found regional differences in pro-excitatory shifts of the excitatory to inhibitory (E/I) current ratio that correlates positively with toxic proteins and degree of pathology, and impinges negatively on cognitive performance scores. Using these data with electrophysiologically anchored analysis of the synapto-proteome in the same individuals, we identified a group of proteins sustaining synaptic function and those related to synaptic toxicity. We also found an uncoupling between the function and expression of proteins for GABAergic signaling in the temporal cortex underlying larger E/I and worse cognitive performance. Further analysis of transcriptomic and in situ hybridization datasets from an independent cohort across the continuum of AD confirm regional differences in pro-excitatory shifts of the E/I balance that correlate negatively with the most recent calibrated composite scores for memory, executive function, language and visuospatial abilities, as well as overall cognitive performance. These findings indicate that early shifts of E/I balance may contribute to loss of cognitive capabilities in the continuum of AD clinical syndrome.
Source: Acta Neuropathologica
Language: English
Subfield: Physiology
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $4,790
Awards: G1241243500, G1458362881, G2142974134, G2950952229, G3041294222, G333817976, G4547540612, Synaptic Actin Regulatory Proteins in Down Syndrome, G5270059849, A Targeted Proteomics and Metabolomics Mass Spectrometry Core Facility at the University of Texas Medical Branch at Galveston, G7816467200, G9000087139, G9000112075, G9000134521, G9000182277, G9000325123, Adult Changes in Thought (ACT) Research Program, Mechanisms of Synaptic Protection in Cognitive Resilence to Alzheimer's Disease Neuropathology, University of Washington Alzheimer's Disease Research Center, G922941218
OpenAlex ID: W4313424315