ACS Chemical Neuroscience最新文献

Alzheimer’sdisease (AD) is a progressive neurodegenerativedisorder with no disease-modifying therapeutics. The P2X7 receptor(P2X7R) presents as a promising target for AD drug discovery due toits pathogenic role in the onset and progression of neuroinflammation,a hallmark pathology of AD. There has been extensive pre-clinicalwork on the development of P2X7R antagonists, but there is yet tobe a therapeutic that has progressed for further clinical evaluationin Alzheimer’s disease. To accelerate the discovery and translationof P2X7R antagonists for AD, better in vitro screeningmodels are needed. Current models such as immortalized cell linesfail to replicate the complexity of physiological disease, and animalmodels present hurdles due to poor translatability, and low accuracyin predicting safety and efficacy of therapeutics. However, inducedpluripotent stem cells (iPSCs) may allow bridging of the gap betweenpreclinical screening methods and human disease. These patient-derivedcells allow the genetic material of donors to be harvested, betterrecapitulating the multifaceted aspects of disease. iPSC-derived neuronsand glia may facilitate the creation of more successful disease modellingand drug screening platforms, allowing for a greater understandingof the underlying disease pathology. Current work in the central nervoussystem (CNS) drug discovery space has demonstrated that the P2X7Ris functional in disease-relevant iPSC models, supporting their suitabilityfor pharmacological investigation. More importantly, they providea robust platform that may drive the development of P2X7R antagonistsfrom pre-clinical studies into a clinical setting.

Apolipoprotein E(APOE) and triggering receptorexpressed on myeloid cells 2 (TREM2) are the twostrongest genetic risk factors of late-onset Alzheimer’s disease.ApoE binds to the low-density lipoprotein receptor (LDLR) to facilitatethe uptake of ApoE-lipoprotein particles. TREM2 is a cell surfacereceptor expressed on microglia in the brain. The activation of TREM2is essential for microglia to carry out protective functions againstAD pathology. Several studies have shown that TREM2 signaling is activatedthrough direct interaction between TREM2 and ApoE. In addition toits important role in AD pathogenesis, the ApoE/TREM2 interactionhas been shown to induce immunosuppression of neutrophils within thetumor microenvironment. Despite its clinical importance, a high-resolutionmolecular understanding of the complex remains elusive. Here, we carriedout chemical cross-linking mass spectrometry (XL-MS) analysis of theApoE3/TREM2_ECD complex to identify intra- and interproteincross-links, which were used as restraints to guide integrative protein–proteindocking. Our data support a binding model in which a helix–loop–helixmotif within the ApoE3 hinge and C-terminal region forms a transientbinding pocket that wraps around the hydrophobic tip of the TREM2ectodomain. This model is further supported by de novo-designed miniprotein binders, which show the same binding mode asidentified by our XL-MS experiment. These results establish a robustframework for developing miniprotein-based TREM2 agonists.

Carriers of the fragile X messenger ribonucleoprotein 1 (FMR1) gene have an elevated risk of developing Fragile X-associated tremor/ataxia syndrome (FXTAS), a progressive late-onset neurodegenerative disorder. Expansion of CGG trinucleotide repeats within the 5' untranslated region leads to RNA-mediated toxicity and promotes the aggregation of toxic FMR1polyglycine (FMR1polyG), driving neuronal dysfunction and degeneration. Yet, effective therapies that alter disease progression remain lacking. In this study, we evaluated a drug repurposing strategy to modulate FXTAS pathogenesis by targeting CGG repeat RNA structures using Itraconazole (ITZ), a clinically approved antifungal, in combination with Lacosamide (LCM), an established antiepileptic drug. The ITZ+LCM combination significantly reduced FMR1polyG aggregation and attenuated oxidative stress and cell death in an in vivoDrosophila model of FXTAS. Notably, this combination also improved locomotor performance and extended the lifespan of model flies, with a fourfold reduction in the effective ITZ dose. These findings were further validated at the cellular level using (CGG)99 transfected HEK293T and COS-7 cells, wherein the ITZ+LCM treatment suppressed FMR1polyG aggregation and corrected CGG repeat splicing defects. Biophysical studies revealed the selective interaction of the drug combination with CGG-expanded RNA. These findings identify the ITZ+LCM combination as a promising, clinically translatable therapeutic strategy against FXTAS to counter RNA-mediated neurotoxicity.

Integrated neuralsignaling and gut microbiome analysis are crucialfor the mechanistic understanding of environmental exposure and health.Photochemical smog is a societal challenge; formaldehyde is a componentof photochemical smog and a common indoor air pollutant. Althoughdepression-like behavior has been linked to formaldehyde exposure,the effect of exposure on real-time dopamine release remains unknowndespite its significance in depression. Here, we reveal the effectsof formaldehyde exposure on real-time dopamine concentration dynamicsin the nucleus accumbens, elicited by electrically stimulating themedial forebrain bundle. We used fast-scan cyclic voltammetry andcarbon fiber microelectrodes to quantify real-time dopamine concentrationdynamics. In addition, we extracted DNA from the mice’s fecalsamples and conducted 16S rRNA gene sequencing to measure the gutmicrobiome. We observed a decrease in real-time dopamine concentrationdynamics in the nucleus accumbens associated with formaldehyde exposure,with peak dopamine concentration being 2700 ± 500 nM (no exposure),2100 ± 400 nM (3-h exposure), and 1600 ± 500 nM (7-day exposure).By quantifying dopamine release in the nucleus accumbens evoked byelectrically stimulating the medial forebrain bundle, we elucidatedhow formaldehyde exposure affects the associated neuronal circuitry.These experiments are the first, to the best of our knowledge, todemonstrate a significant decrease (p < 0.05)in real-time dopamine release in the nucleus accumbens following formaldehydeexposure in a duration-dependent manner. Additionally, gut microbiomeanalysis suggested a decrease in Lactobacillus, which has immunomodulatory functions, after 7 days of formaldehydeexposure.

Spinal muscular atrophy (SMA) is a severe neuromusculardisordercaused by homozygous deletions or mutations in the SMN1 gene, resulting in reduced levels of the ubiquitously expressedsurvival motor neuron protein and progressive degeneration of lowermotor neurons. Although autophagy dysregulation has been implicatedin SMA pathology, the therapeutic benefit of modulating this pathwayremains controversial. Here, we screened autophagy modulators in apreviously characterized Caenorhabditis elegans SMAmodel. We identified that pharmacological activation of autophagy,but not inhibition, significantly improved neuromuscular function,as indicated by two independent functional readouts: pharyngeal pumpingand locomotor activity assays. These beneficial effects were validatedin an independent severe C. elegans SMA mutant alleleand were observed in metabolically active and inactive food conditions.Furthermore, autophagy activators significantly extended lifespanof SMA nematodes without affecting controls. Notably, rapamycin andresveratrol increased endogenous SMN-1 protein levels, and improvedneuromuscular function was dependent on an intact autophagy pathway.Collectively, our findings support enhancing autophagic activity asa combinatorial treatment strategy for SMA patients.

Alzheimer’s disease (AD), an age-associated neurodegenerativedisorder characterized by cognitive decline and accumulation of amyloid-β(Aβ) plaques and tau tangles, has long been studied throughthe lens of protein aggregation and phosphorylation. However, emergingevidence suggests that aberrant protein N-glycosylation,a key post-translational modification governing protein folding, trafficking,and signaling, plays an equally pivotal role in AD pathogenesis. Thisreview consolidates current knowledge on N-glycosylation,and very briefly about the prominent O-Glycosylation dynamics in thehealthy and diseased brain, with a focus on six key proteins amyloidprecursor protein, immunoglobulin G (IgG), triggering receptor expressedon myeloid cells-2 (TREM2), tau (τ), apolipoprotein E, and transferrinwhose altered glycosylation patterns perturb amyloidogenic processing,tau aggregation, microglial activity, lipid transport, and systemicimmune balance. We introduce the glyco-remodeling hypothesis, proposing that stage-specific glycosylation changes act as molecular“remodeling” driving the progression from normal aging,to mild cognitive impairment, and ultimately AD. Framing AD throughthis lens positions glycans as both markers and modulators of diseaseprogression, with direct implications for biomarker discovery, therapeutictargeting, and systems-level integration across aging and neurodegeneration.

The accumulationof the Aβ42 peptide is one of the key factorsin the progression of Alzheimer’s disease, as it disrupts synapticsignaling and impairs neuronal function. Although the peptide is knownto compromise plasma membrane integrity, the detailed mechanisms underlyingbilayer alterations and lipid–Aβ42 interactions remainunclear. In the present study, electrochemical impedance spectroscopyand fluorescence lifetime imaging microscopy were employed to investigatethe impact of oligomeric Aβ42 on model membranes that mimicthe lipid composition of the outer leaflet of the neuronal plasmamembrane. Our results demonstrate that the presence of SM or GM1 withina DOPC/Chol backbone is enough to facilitate Aβ42 interactionwith the membrane, as evidenced by increased membrane microviscosity;however, this interaction alone is insufficient to induce permeability-enhancingdefects in the membrane. Extensive disruption of bilayer integrityrequired the complete lipid ensemble present in the outer leafletof the neuronal membrane-mimicking composition, indicating that not only specific lipids but also their cooperative interplay and organizationwithin the lipid bilayer are essential for Aβ42-induced membranepermeabilization.

Prenatal ethanolexposure (PE) causes fetal alcohol spectrum disorders(FASD), which have a high prevalence in the United States. There arevarious cognitive and behavioral deficits in FASD, including increasedaddiction risk. The diagnosis of FASD is often delayed, and thereare no effective pharmacological treatments available for FASD. Persistentneuroinflammation, driven by microglial activation, may underlie cognitiveand behavioral deficits in FASD. In the present study, we investigatedwhether suppressing microglial activation by chronic minocycline treatmentduring preadolescence and early adolescence could ameliorate addictionrisk in PE rats. Pregnant Sprague–Dawley rats received intragastricgavages of ethanol (6 g/kg/day; gestation days 8–20) to simulateheavy drinking during pregnancy in humans. Control rats received anisocaloric sucrose solution. We initiated chronic minocycline or vehicletreatment (33 mg/kg; i.p.; 5 days/week for 3 weeks) in female offspringbetween postnatal days 21 and 29. In rats treated with vehicle, PEled to increased amphetamine self-administration, indicating increasedaddiction risk. Chronic minocycline led to a reduction in amphetamineself-administration in PE rats but not in controls. Microglia morphologyanalysis in the ventral tegmental area showed that PE decreased thebranch number of microglia, which was partially reversed by minocyclinetreatment, supporting that PE-induced addiction risk can be amelioratedby reducing PE-induced microglia activation. Minocycline is welltolerated in clinical settings. Our results inform a promising pharmacologicaltreatment strategy for FASD.

Converging evidence implicates dysregulation of serotoninin emotion-relatedpsychiatric disorders. Leading pharmacotherapies for such disorders,including general anxiety and posttraumatic stress disorders, targetthe serotonin transporter (SERT); yet, selective serotonin reuptakeinhibitors (SSRIs) exhibit limited efficacy, suggesting that additionalmechanisms contribute to these clinically prevalent psychopathologies.Recent evidence suggests that organic cation transporter 3 (OCT3)contributes to serotonin homeostasis; however, OCT3 contributionsto serotonin clearance in basolateral amygdala (BLA), a central hubfor emotional processing, are unknown. We utilized transgenic mice, in vivo neurochemical, and behavioral approaches to testOCT3 contributions to serotonin clearance in BLA and fear behaviors.Depletion of OCT3 from serotonin neurons prolonged serotonin clearancein BLA across a range of concentrations, in comparison to depletionof SERT from serotonin neurons, which prolonged serotonin clearancein BLA only at relatively low concentrations. The SSRI fluvoxamineprolonged serotonin clearance in BLA of wildtype mice and OCT3 knockdownmice to a similar degree, and this effect was lost in mice with SERTdepletion. Behaviorally, depletion of SERT or OCT3 from serotoninneurons did not impact fear learning; however, depletion of SERT trendedto attenuate cued fear memory, and depletion of OCT3 modestly attenuatedcued and contextual fear memory. These findings indicate that OCT3could serve as a novel therapeutic target for psychiatric disordersrelated to emotional dysregulation and encourage research into nonconventionaltreatments for these prevalent disorders.

We report on the development of a highly water-solublepegylatedimidazodiazepine ETK-II-83. The compound binds selectively to GABA_A receptors among forty-five other receptors expressed in thebrain with a higher affinity for the α5-containing GABA_A receptors. The compound is converted in vitro by liver microsomes into ETK-III-9. The metabolic reaction selectivelyoxidizes the polyethylene glycol groups of ETK-II-83 forming eventuallythe stable 2-hydroxyethyl amide-bearing ETK-III-9. The conversionis fast with a half-life of 5.33 min. ETK-III-9 strongly binds toα3/α5 containing GABA_A receptors. A pharmacokineticstudy with ETK-II-83 confirmed metabolic instability resulting inlow AUCs for blood and brain. Interestingly, higher brain concentrationsthan blood concentrations (K_P = 5.17) were observed. Thein vivo formation of ETK-III-9 inside ETK-II-83-treated animals wasrapid and peaked at 40 min. Almost equal amounts of ETK-III-9 werefound in blood and brain with half-lives of 219 and 202 min, respectively.We also conducted a pharmacokinetic study with ETK-III-9 at the samedose and observed three times higher AUCs for blood and brain. Importantly,the free brain concentration of ETK-III-9 in ETK-II-83-administratedanimals was higher than its affinity for the GABA_A receptors.This was confirmed by investigating ETK-II-83 with two anxiety mousemodels. For the elevated plus maze, ETK-III-9- and ETK-II-83-treatedanimals spent significantly more time in the open arm than vehicle-treatedanimals, without any differences in the overall distance traveled.ETK-III-9- and ETK-II-83-treated animals also buried fewer marblesthan vehicle control animals. To demonstrate that these effects werenot caused by sedation or inhibition of sensorimotor inhibition, weconducted open field and rotarod tests. For both tests, ETK-III-9-and ETK-II-83-treated animals did not behave differently from vehicle-treatedmice in contrast to diazepam-treated animals. The innovation is ahighly water-soluble prodrug ETK-II-83 that metabolizes to ETK-III-9,an α3/α5 GABA_A receptor-selective compoundthat reduces anxiety in rodent models.