Alzheimer's disease-like brain pattern biomarker: capturing risks and predicting disease onset.

Most recent data from the Centers for Disease Control (CDC) estimated that there were 140,000 deaths per year attributable to excessive alcohol use [, ]. Similarly, the 2022 National Survey on Drug Use and Health estimated that 29.5 million people ages 12 and older meet the criteria for alcohol use disorder (AUD), which is defined by an impaired ability to stop or control drinking despite adverse social, occupational, or health consequences []. AUD is far-reaching and places an overwhelming burden on afflicted individuals, their families, and their communities. Currently available pharmacological therapies that aim to reduce dependence on alcohol have only modest success treating AUD [, ], highlighting, at least in part, our limited knowledge of brain changes in AUD patients, and the need to better understand alcohol-related changes to aid the development of more effective therapies. Notably, the dorsolateral prefrontal cortex (DLPFC) is a key region involved in the reward-processing of alcohol use [–] and its modulation has been proposed as a potential treatment for AUD []. Indeed, prefrontal cortex (PFC) hyperexcitability in alcohol-dependent individuals [] suggests deficits in cortical inhibitory transmission, which is carried out by γ-aminobutyric acid type A receptors (GABARs), a well-known alcohol target []. This is also supported by previous research demonstrating reduction in cortical mRNA levels of specific GABARs subunits in AUD postmortem brain samples []. GABARs are pentametric ionotropic complexes that result from distinct subunit compositions through the combination of 19 subunits []. The combination of subunits, or the stoichiometry, of each receptor determines its trafficking, membrane location, biophysics, pharmacological properties, and function [–]. Importantly, previous evidence has shown that remodeling of GABARs is implicated in alcohol dependence [, , ] suggesting that changes to GABARs subunit combinations resulting from ethanol exposure can contribute to changes in GABARs function. In support of this, animal models of chronic ethanol exposure consistently demonstrate decreases in synaptic α1 subunit expression [, ]. These deficits correlate with enhanced decay of cortical inhibitory post synaptic currents (IPSCs) of ethanol-treated rats, and higher frequency of spontaneous IPSCs without changes in amplitude []. Additionally, rat cortical neurons in culture exposed to ethanol exhibited significantly shortened decay time constant of miniature IPSCs without significant changes in frequency or current amplitude in comparison with controls [], suggesting changes in the kinetics of GABARs which may be associated to subunit rearrangements. While the information gained from animal studies provides invaluable knowledge regarding ethanol’s effects on GABARs in the mammalian brain, preclinical models of alcohol use and dependence are inherently limited due to rodents’ natural aversion to alcohol consumption []. Furthermore, experimental animal models in which ethanol-treated animals are compared to ethanol-naïve animals may not accurately reflect differences between alcohol dependence and typical human alcohol use because not all individuals that consume alcohol develop AUD []. Therefore, the potential structural and functional changes of native GABARs in humans with AUD are not clearly understood. In this study, we directly recorded the electrophysiological activity of reactivated native synaptic GABARs from the DLPFC of AUD individuals and correlated observed changes with different levels of multi-omics data to uncover potential GABARs modifications associated with AUD. Our findings definitively prove that AUD post-mortem GABAR from AUD post-mortem tissue can be reactivated and their functional activity can be measured. Additionally, we hypothesized that GABARs from AUD individuals would exhibit significantly lower levels of GABAR subunit transcripts and proteins, as well as significantly blunted function when compared with controls. However, our data suggests that chronic alcohol use can affect synaptic GABARs at the level of the transcriptome through mechanisms that do not translate permanently to significant changes in GABAR subunit composition or post-synaptic function in the DLPFC, similar to post-translational buffering processes which attenuate mRNA expression deviations and prevent them from propagating to the level of protein expression [–]. The methodology described in this project provides, for the first time, a solid schema for reactivating AUD post-synaptic receptors and integrating this information with multiple levels of multi-omics data. Additionally, our results provide hypothesis-generating insights into this complex disease and lay the foundation for future dynamic research of this distressing and prevalent disorder.