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N-methyl-D-aspartate receptors (NMDAR), ionotropic glutamate receptors, mediate a slow component of excitatory synaptic transmission in the central nervous system and play a key role in normal brain function and development. Genetic variations in GRIN genes encoding NMDAR subunits that alter the receptor's functional characteristics are associated with a wide range of neurological and neuropsychiatric conditions. Pathological GRIN variants located in the M2 re-entrant loop lining the channel pore cause significant functional changes, the most consequential alteration being a reduction in voltage-dependent Mg 2+ inhibition. Voltage-dependent Mg 2+ block is a unique feature of NMDAR biology whereby channel activation requires both ligand binding and postsynaptic membrane depolarization. Thus, loss of NMDAR Mg 2+ block will have a profound impact on synaptic function and plasticity. Here, we choose 11 missense variants within the GRIN1, GRIN2A, and GRIN2B genes that alter residues located in the M2 loop and significantly reduce Mg 2+ inhibition. Each variant was evaluated for tolerance to genetic variation using the 3-dimensional structure and assessed for functional rescue pharmacology via electrophysiological recordings. Three FDA-approved NMDAR drugs-memantine, dextromethorphan, and ketamine-were chosen based on their ability to bind near the M2 re-entrant loop, potentially rectifying dysregulated NMDAR function by supplementing the reduced voltage-dependent Mg 2+ block. These results provide insight of structural determinants of FDA-approved NMDAR drugs at their binding sites in the channel pore and may further define conditions necessary for the use of such agents as potential rescue pharmacology., (© 2023 International Society for Neurochemistry.)

Genetic variants in the genes GRIN1, GRIN2A, GRIN2B, and GRIN2D, which encode subunits of the N-methyl-D-aspartate receptor (NMDAR), have been associated with severe and heterogeneous neurologic and neurodevelopmental disorders, including early onset epilepsy, developmental and epileptic encephalopathy, intellectual disability, and autism spectrum disorders. Missense variants in these genes can result in gain or loss of the NMDAR function, requiring opposite therapeutic treatments. Computational methods that predict pathogenicity and molecular functional effects of missense variants are therefore crucial for therapeutic applications. We assembled 223 missense variants from patients, 631 control variants from the general population, and 160 missense variants characterized by electrophysiological readouts that show whether they can enhance or reduce the function of the receptor. This includes new functional data from 33 variants reported here, for the first time. By mapping these variants onto the NMDAR protein structures, we found that pathogenic/benign variants and variants that increase/decrease the channel function were distributed unevenly on the protein structure, with spatial proximity to ligands bound to the agonist and antagonist binding sites being a key predictive feature for both variant pathogenicity and molecular functional consequences. Leveraging distances from ligands, we developed two machine-learning based predictors for NMDA variants: a pathogenicity predictor which outperforms currently available predictors and the first molecular function (increase/decrease) predictor. Our findings can have direct application to patient care by improving diagnostic yield for genetic neurodevelopmental disorders and by guiding personalized treatment informed by the knowledge of the molecular disease mechanism., (© The Author(s) 2024. Published by Oxford University Press.)

N-methyl-D-aspartate receptors (NMDARs) comprise a family of ligand-gated ionotropic glutamate receptors that mediate a slow, calcium-permeable component to excitatory neurotransmission. The GluN2D subunit is enriched in GABAergic inhibitory interneurons in cortical tissue. Diminished levels of GABAergic inhibition contribute to multiple neuropsychiatric conditions, suggesting that enhancing inhibition may have therapeutic utility, thus making GluN2D modulation an attractive drug target. Here, we describe the actions of a GluN2C/GluN2D-selective positive allosteric modulator (PAM), (+)-EU1180-453, which has improved drug-like properties such as increased aqueous solubility compared to the first-in-class GluN2C/GluN2D-selective prototypical PAM (+)-CIQ. (+)-EU1180-453 doubles the NMDAR response at lower concentrations (< 10 μM) compared to (+)-CIQ, and produces a greater degree of maximal potentiation at 30 μM. Using in vitro electrophysiological recordings, we show that (+)-EU1180-453 potentiates triheteromeric NMDARs containing at least one GluN2C or GluN2D subunit, and is active at both exon5-lacking and exon5-containing GluN1 splice variants. (+)-EU1180-453 increases glutamate efficacy for GluN2C/GluN2D-containing NMDARs by both prolonging the deactivation time and potentiating the peak response amplitude. We show that (+)-EU1180-453 selectively increases synaptic NMDAR-mediated charge transfer onto P11-15 CA1 stratum radiatum hippocampal interneurons, but is without effect on CA1 pyramidal cells. This increased charge transfer enhances inhibitory output from GABAergic interneurons onto CA1 pyramidal cells in a GluN2D-dependent manner. (+)-EU1180-453 also shifts excitatory-to-inhibitory coupling towards increased inhibition and produces enhanced gamma band power from carbachol-induced field potential oscillations in hippocampal slices. Thus, (+)-EU1180-453 can enhance overall circuit inhibition, which could prove therapeutically useful for the treatment of anxiety, depression, schizophrenia, and other neuropsychiatric disorders., Significance Statement: Interneuron dysfunction and diminished GABAergic inhibition in neocortical and hippocampal circuits remains a prominent molecular hypothesis for neuropsychiatric diseases including anxiety, depression, and schizophrenia. Pharmacological agents that boost GABA receptor function have shown utility in various forms of depression and treating symptoms of schizophrenia. Cortical GABAergic interneurons, unlike their excitatory pyramidal cell counterparts, are enriched for the GluN2D subunit of the NMDA receptor. Thus, GluN2D subunit-selective modulation could be a useful therapeutic tool to enhance local inhibition, improving the prognosis for neuropsychiatric diseases for which interneuron dysfunction is prominent and causal to circuit aberration., Competing Interests: Conflict of interest: D.C.L., H.Y., M.P.E., N.S.A., and S.F.T. are co-inventors of Emory-owned intellectual property. S.F.T. is a member of the SAB for Sage Therapeutics, Eumentis Therapeutics, Neurocrine, the GRIN2B Foundation, the CureGRIN Foundation, and CombinedBrain. S.F.T. is a consultant for GRIN Therapeutics. H.Y. is the PI on a research grant from Sage Therapeutics and GRIN Therapeutics to Emory. S.F.T. is PI on a research grant from GRIN Therapeutics to Emory. S.F.T. is cofounder of NeurOp, Inc. and Agrithera. D.C.L. and S.F.T. are on the Board of Directors for NeurOp. T.A.B. is a member of the SAB for GRIN2B Foundation, CureGRIN Foundation and GRIN Therapeutics; all remuneration has been made to his department.

Phosphodiesterases (PDEs) constitute a superfamily of phosphohydrolytic enzymes that regulate intracellular second messenger signaling by hydrolyzing cyclic adenosine monophosphate and cyclic guanosine monophosphate. Among the 11 subfamilies of PDEs, phosphodiesterase 1 (PDE1) stands out due to its broad implications in central and peripheral pathologies. There are three subtypes of PDE1: PDE1A, PDE1B, and PDE1C. While PDE1A and PDE1C are distributed in both the brain and peripheral organs, PDE1B is predominantly expressed in the brain, rendering it an attractive drug target for neurological and psychological disorders. Despite continuous efforts dedicated to the development of novel PDE1 inhibitors, a suitable PDE1 radioligand for human use is currently lacking. In this study, we present the identification and preclinical evaluation of [ 11 C]PF-04822163, a selective radioligand candidate for imaging PDE1 with positron emission tomography. PF-04822163 exhibits excellent potency toward PDE1 and demonstrates great target selectivity over other PDEs. Then, PF-04822163 was labeled with carbon-11 (half-life, 20 min) in favorable radiochemical yields (25 ± 10%, decay-corrected) and high molar activities (106-194 GBq/μmol). Further, in vitro and in vivo evaluations in rodents suggested that [ 11 C]PF-04822163 displayed good brain penetration and a rapid washout. Despite these promising performance characteristics of [ 11 C]PF-04822163, only marginal specific binding was observed in vivo . Further optimization of the scaffold is warranted to obtain favorable pharmacological and ADME properties., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Metabotropic glutamate receptor 7 (mGlu 7 ) is a G protein-coupled receptor that is preferentially found in the active zone of neurotransmitter release in the central nervous system (CNS). mGlu 7 plays a vital role in memory, learning, and neuronal development, rendering it a potential target for treating epilepsy, depression, and anxiety. The development of noninvasive imaging ligands targeting mGlu 7 could help elucidate the functional significance of mGlu 7 and accelerate drug discovery for neurological and psychiatric disorders. In this report, a novel carbon-11 labeled positron emission tomography (PET) tracer designated [ 11 C]18 (codenamed MG7-2109) was synthesized via 11 C-methylation in 23% decay-corrected radiochemical yield (RCY). In vitro serum stability, serum protein binding, in vitro autoradiography and ex vivo biodistribution studies of [ 11 C]18 were conducted. Preliminary PET imaging results revealed a homogeneous distribution of [ 11 C]18 and rapid clearance in rodent brains. This study provides valuable insights into the development of mGlu 7 -targeted PET tracer based on an isoxazolo(5,4-c)pyridine scaffold., Competing Interests: None., (AJNMMI Copyright © 2024.)

Glycogen synthase kinase 3 (GSK3) is a multifunctional serine/threonine kinase family that regulates diverse biological processes including glucose metabolism, insulin activity and energy homeostasis. Dysregulation of GSK3 is implicated in the development of several diseases such as type 2 diabetes mellitus, Alzheimer's disease (AD), and various cancer types. In this study, we report the synthesis and evaluation of a novel positron emission tomography (PET) ligand compound 28 (codenamed [ 18 F]GSK3-2209). The PET ligand [ 18 F]28 was obtained via copper-mediated radiofluorination in more than 32% radiochemical yields, with high radiochemical purity and high molar activity. In vitro autoradiography studies in rodents demonstrated that this tracer exhibited a high specific binding to GSK3. Furthermore, PET imaging studies of [ 18 F]28 revealed its ability to penetrate the blood-brain barrier (BBB)., Competing Interests: None., (AJNMMI Copyright © 2024.)

Background: Dorsal ramus medial branch radiofrequency ablation is reported to be effective for refractory lumbar facet joint syndrome. However, as nerve fibers can regenerate, the therapeutic effect was reported to be short and last only 6 to 12 months. Previously, we reported a novel endoscopic joint capsule and articular process excision procedure. In that case, a satisfying effect was achieved by removing the culprit hyperplastic articular synovial entrapped in the joint space endoscopically. We presume this treatment is an etiologic treatment and can exert longer-term efficacy., Aim: This retrospective clinical trial aimed to elucidate the longer-term efficacy as well as the safety profile of the procedure., Methods: This was a retrospective descriptive study. The participants underwent endoscopic joint capsule and articular process excision procedures. The Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) before the operation, and at 3 months, 6 months, 1 year, and 2 years post-operation were recorded by reviewing medical charts and conducting telephone interviews., Results: A total of 234 participants were evaluated in the trial. After participant screening, 13 participants were included in the final analysis. The VAS score was reduced from (median (P25, P75)) 6 (4.5, 6) at pre-operation to 2 (0, 4) at 1-year post-operation and 0 (0, 1) at 2-year pre-operation. The ODI score was reduced from 37.78 (27.09, 59.95) at pre-operation to 8.89 (2.22, 24.34) at 1-year post-operation and 6 (0.02, 11.11) at 2-year post-operation. The difference was statistically significant. Further subgroup analysis demonstrated that a narrowed intervertebral space was a possible relevant factor for poor outcomes. No procedure-related complications were reported., Conclusion: Endoscopic joint capsule and articular process excision is an effective and safe procedure for refractory lumbar facet joint syndrome. The effectiveness duration can last up to 1 to 2 years., Competing Interests: The authors report no conflicts of interest in this work., (© 2024 Tang et al.)

The histamine subtype 3 (H 3 ) receptor is an important drug target in the central nervous system (CNS), and PET imaging offers a promising technique for the noninvasive evaluation of CNS disease related to the H 3 receptor. In this study, we synthesized and evaluated the binding effects of [ 18 F]H3-2404 and [ 18 F]H3-2405 by modifying the structure of AZD5213, a selective H 3 antagonist. These two radioligands were prepared in high radiochemical yields and displayed stability in serum. The in vitro autoradiographic study in rat brain tissue and the following in vivo PET studies in mice demonstrated sufficient brain uptake but predominantly non-specific distribution in rodent brain. Although these data suggest that [ 18 F]H3-2404 and [ 18 F]H3-2405 are unsuitable as PET tracers for brain imaging of the H 3 receptor, this study provides a valuable attempt for optimizing 18 F labeled radiotracers based on AZD5213., (© 2024 Wiley-VCH GmbH.)

Objective: GRIN1 -related neurodevelopmental disorder ( GRIN1 -NDD) is characterized by clinically significant variation in the GRIN1 gene, which encodes the obligatory GluN1 subunit of N-methyl-D-aspartate receptors (NMDARs). The identified p.Tyr647Ser (Y647S) variant - carried by a 33-year-old female with seizures and intellectual disability - is located in the M3 helix in the GluN1 transmembrane domain. This study builds upon initial in vitro investigations of the functional impacts of the GRIN1 Y647S variant and examines its in vivo consequences in a mouse model., Methods: To investigate in vitro functional impacts of NMDARs containing GluN1-Y647S variant subunits, GluN1-Y647S was co-expressed with wildtype GluN2A or GluN2B subunits in Xenopus laevis oocytes and HEK cells. Grin1 Y647S/+ mice were created by CRISPR-Cas9 endonuclease-mediated transgenesis and the molecular, electrophysiological, and behavioural consequences of the variant were examined., Results: In vitro , NMDARs containing GluN1-Y647S show altered sensitivity to endogenous agonists and negative allosteric modulators, and reduced cell surface trafficking. Grin1 Y647S/+ mice displayed a reduction in whole brain GluN1 levels and deficiency in NMDAR-mediated synaptic transmission in the hippocampus. Behaviourally, Grin1 Y647S/+ mice exhibited spontaneous seizures, altered vocalizations, muscle strength, sociability, and problem-solving., Interpretation: The Y647S variant confers a complex in vivo phenotype, which reflects largely diminished properties of NMDAR function. As a result, Grin1 Y647S/+ mice display atypical behaviour in domains relevant to the clinical characteristics of GRIN1 -NDD and the individual carrying the variant. Ultimately, the characterization of Grin1 Y647S/+ mice accomplished in the present work expands our understanding of the mechanisms underlying GRIN1 -NDD and provides a foundation for the development of novel therapeutics.

Joint source-channel coding (JSCC) based on deep learning has shown significant advancements in image transmission tasks. However, previous channel-adaptive JSCC methods often rely on the signal-to-noise ratio (SNR) of the current channel for encoding, which overlooks the neural network's self-adaptive capability across varying SNRs. This paper investigates the self-adaptive capability of deep learning-based JSCC models to dynamically changing channels and introduces a novel method named Channel-Blind JSCC (CBJSCC). CBJSCC leverages the intrinsic learning capability of neural networks to self-adapt to dynamic channels and diverse SNRs without relying on external SNR information. This approach is advantageous, as it is not affected by channel estimation errors and can be applied to one-to-many wireless communication scenarios. To enhance the performance of JSCC tasks, the CBJSCC model employs a specially designed encoder-decoder. Experimental results show that CBJSCC outperforms existing channel-adaptive JSCC methods that depend on SNR estimation and feedback, both in additive white Gaussian noise environments and under slow Rayleigh fading channel conditions. Through a comprehensive analysis of the model's performance, we further validate the robustness and adaptability of this strategy across different application scenarios, with the experimental results providing strong evidence to support this claim.

N-methyl-D-aspartate receptors (NMDARs) are members of the glutamate receptor family and participate in excitatory postsynaptic transmission throughout the central nervous system. Genetic variants in GRIN genes encoding NMDAR subunits are associated with a spectrum of neurological disorders. The M3 transmembrane helices of the NMDAR couple directly to the agonist-binding domains and form a helical bundle crossing in the closed receptors that occludes the pore. The M3 functions as a transduction element whose conformational change couples ligand binding to opening of an ion conducting pore. In this study, we report the functional consequences of 48 de novo missense variants in GRIN1, GRIN2A, and GRIN2B that alter residues in the M3 transmembrane helix. These de novo variants were identified in children with neurological and neuropsychiatric disorders including epilepsy, developmental delay, intellectual disability, hypotonia and attention deficit hyperactivity disorder. All 48 variants in M3 for which comprehensive testing was completed produce a gain-of-function (28/48) compared to loss-of-function (9/48); 11 variants had an indeterminant phenotype. This supports the idea that a key structural feature of the M3 gate exists to stabilize the closed state so that agonist binding can drive channel opening. Given that most M3 variants enhance channel gating, we assessed the potency of FDA-approved NMDAR channel blockers on these variant receptors. These data provide new insight into the structure-function relationship of the NMDAR gate, and suggest that variants within the M3 transmembrane helix produce a gain-of-function., (© 2024. The Author(s).)

AMPA glutamate receptors (AMPARs) play a pivotal role in excitatory neurotransmission, particularly in the hippocampus where the TARP γ-8 subunit is enriched and serves as a target for emerging anti-epileptic drugs. To enable in vivo visualization of TARP γ-8 distribution and expression by positron emission tomography (PET), this study focuses on the development of novel 18 F-labeled TARP γ-8 inhibitors and their corresponding precursors, stemming from the azabenzimidazole scaffold. The resulting radioligands [ 18 F]TARP-2204 and [ 18 F]TARP-2205 were successfully synthesized with acceptable radiochemical yield, high molar activity, and excellent radiochemical purity. In vitro autoradiography demonstrates high level of specific binding of [ 18 F]TARP-2205 to TARP γ-8 in both rat and nonhuman primate brain tissues. However, unexpected radiodefluorination in PET imaging studies of rodents emphasizes the need for further structural refinement. This work serves as an excellent starting point for the development of future 18 F-labeled TARP γ-8 PET tracers, offering valuable insights into medicinal chemistry design, radiosynthesis and subsequent PET evaluation., (© 2024 Wiley-VCH GmbH.)

GRID1 and GRID2 encode the enigmatic GluD1 and GluD2 proteins, which form tetrameric receptors that play important roles in synapse organization and development of the central nervous system. Variation in these genes has been implicated in neurodevelopmental phenotypes. We evaluated GRID1 and GRID2 human variants from the literature, ClinVar, and clinical laboratories and found that many of these variants reside in intolerant domains, including the amino terminal domain of both GRID1 and GRID2. Other conserved regions, such as the M3 transmembrane domain, show different intolerance between GRID1 and GRID2. We introduced these variants into GluD1 and GluD2 cDNA and performed electrophysiological and biochemical assays to investigate the mechanisms of dysfunction of GRID1/2 variants. One variant in the GRID1 distal amino terminal domain resides at a position predicted to interact with Cbln2/Cbln4, and the variant disrupts complex formation between GluD1 and Cbln2, which could perturb its role in synapse organization. We also discovered that, like the lurcher mutation (GluD2-A654T), other rare variants in the GRID2 M3 domain create constitutively active receptors that share similar pathogenic phenotypes. We also found that the SCHEMA schizophrenia M3 variant GluD1-A650T produced constitutively active receptors. We tested a variety of compounds for their ability to inhibit constitutive currents of GluD receptor variants and found that pentamidine potently inhibited GluD2-T649A constitutive channels (IC50 50 nM). These results identify regions of intolerance to variation in the GRID genes, illustrate the functional consequences of GRID1 and GRID2 variants, and suggest how these receptors function normally and in disease., (© The Author(s) 2023. Published by Oxford University Press.)

Carbohydrazide electrooxidation reaction (COR) is a potential alternative to oxygen evolution reaction in water splitting process. However, the sluggish kinetics process impels to develop efficient catalysts with the aim of the widespread use of such catalytic system. Since COR concerns the adsorption/desorption of reactive species on catalysts, the electronic structure of electrocatalyst can affect the catalytic activity. Interface charge distribution engineering can be considered to be an efficient strategy for improving catalytic performance, which facilitates the cleavage of chemical bond. Herein, highly dispersed Pd nanoparticles on CeO 2 /C catalyst are prepared and the COR catalytic performance is investigated. The self-driven charge transfer between Pd and CeO 2 can form the local nucleophilic and electrophilic region, promoting to the adsorption of electron-withdrawing and electron-donating group in carbohydrazide molecule, which facilitates the cleavage of C-N bond and the carbohydrazide oxidation. Due to the local charge distribution, the Pd-CeO 2 /C exhibits superior COR catalytic activity with a potential of 0.27 V to attain 10 mA cm -2 . When this catalyst is used for energy-efficient electrolytic hydrogen production, the carbohydrazide electrolysis configuration exhibits a low cell voltage (0.6 V at 10 mA cm -2 ). This interface charge distribution engineering can provide a novel strategy for improving COR catalytic activity., (© 2023 Wiley-VCH GmbH.)

N-methyl-D-aspartate (NMDA) receptors mediate a slow component of excitatory synaptic transmission, are widely distributed throughout the central nervous system, and regulate synaptic plasticity. NMDA receptor modulators have long been considered as potential treatments for psychiatric disorders including depression and schizophrenia, neurodevelopmental disorders such as Rett Syndrome, and neurodegenerative conditions such as Alzheimer's disease. New interest in NMDA receptors as therapeutic targets has been spurred by the findings that certain inhibitors of NMDA receptors produce surprisingly rapid and robust antidepressant activity by a novel mechanism, the induction of changes in the brain that well outlast the presence of drug in the body. These findings are driving research into an entirely new paradigm for using NMDA receptor antagonists in a host of related conditions. At the same time positive allosteric modulators of NMDA receptors are being pursued for enhancing synaptic function in diseases that feature NMDA receptor hypofunction. While there is great promise, developing the therapeutic potential of NMDA receptor modulators must also navigate the potential significant risks posed by the use of such agents. We review here the emerging pharmacology of agents that target different NMDA receptor subtypes, offering new avenues for capturing the therapeutic potential of targeting this important receptor class., (© 2023. The Author(s).)

Background: Lumbar spinal stenosis (LSS) is a common pain condition that causes lumbar back pain, radiating leg pain, and possible functional impairment. MILD is an emerging minimally invasive treatment for LSS. It is an image-guided percutaneous procedure designed to debulk hypertrophied ligamentum flavum. However, the exact short- and long-term efficacy, safety profile, indication criteria, and certain procedure details reported in medical literature vary., Objective: This narrative review was to elucidate efficacy, safety profile, certain procedure details, advantages, and limitations of MILD., Study Design: This is a narrative review., Setting: All included articles are clinic trials including analytic studies and descriptive studies., Methods: PubMed, Cochrane Library, and Scopus were searched. Only clinical trials of MILD procedure were included. Information of indications, contraindications, VAS scores, ODI scores, effective rate, efficacy durations, and certain procedure details was focused on., Results: According to the literature, for the MILD procedure, the VAS score could be reduced from a pre-treatment level of 6.3-9.6 to a post-treatment level of 2.3-5.8. The ODI score could be reduced from a pre-treatment level of 38.8-55.3 to a post-treatment level of 27.4-39.8. The effective rate of the MILD procedure was reported to be 57.1%-88%. A 2-year postoperative stability of efficacy was also supported. One RCT study testified superior efficacy of MILD over epidural steroid injection., Limitations: There is few high-quality literature in the review. Moreover, the long-term efficacy of MILD cannot be revealed according to the current literature., Conclusion: Based on the reviewed literature, MILD is an effective and safe procedure. MILD can reduce pain intensity and improve functional status significantly. Therefore, it is a preferable option for LSS patients who failed conservative treatments, but not for those who require immediate invasive decompression surgery., Competing Interests: The authors report no conflicts of interest in this work., (© 2023 Yuan and Yi.)

AMPA receptors are members of the glutamate receptor family and mediate a fast component of excitatory synaptic transmission at virtually all central synapses. Thus, their functional characteristics are a critical determinant of brain function. We evaluate intolerance of each GRIA gene to genetic variation using 3DMTR and report here the functional consequences of 52 missense variants in GRIA1-4 identified in patients with various neurological disorders. These variants produce changes in agonist EC 50 , response time course, desensitization, and/or receptor surface expression. We predict that these functional and localization changes will have important consequences for circuit function, and therefore likely contribute to the patients' clinical phenotype. We evaluated the sensitivity of variant receptors to AMPAR-selective modulators including FDA-approved drugs to explore potential targeted therapeutic options., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Besides medical expenses, hospitalizations associated with air pollution will incur the welfare loss due to activity restrictions and the wage loss due to inability to work. We fill in the gap in the literature by examining the impact of air pollution on volume and intensity of hospitalizations, which allows us to incorporate the welfare loss and the wage loss. Using a data set that covers most of the inpatients in a major Chinese city during 2015-16, we find that worse air quality causes more hospital admissions, more total inpatient days, and higher total inpatient expenditure for various diseases, particularly diseases of the respiratory and circulatory systems. We also find that there would be an underestimate of the loss from air pollution if we had ignored the loss associated with activity restrictions and the wage loss during hospitalization., (© 2023 John Wiley & Sons Ltd.)

Objective: To investigate the clinical features and potential pathogenesis mechanism of de novo CLPTM1 variants associated with epilepsy., Methods: Identify de novo genetic variants associated with epilepsy by reanalyzing trio-based whole-exome sequencing data. We analyzed the clinical characteristics of patients with these variants and performed functional in vitro studies in cells expressing mutant complementary DNA for these variants using whole-cell voltage-clamp current recordings and outside-out patch-clamp recordings from transiently transfected human embryonic kidney (HEK) cells., Results: Two de novo missense variants related to epilepsy were identified in the CLPTM1 gene. Functional studies indicated that CLPTM1-p.R454H and CLPTM1-p.R568Q variants reduced the γ-aminobutyric acid A receptor (GABA A R) current response amplitude recorded under voltage clamp compared to the wild-type receptors. These variants also reduced the charge transfer and altered the time course of desensitization and deactivation following rapid removal of GABA. The surface expression of the GABA A R γ2 subunit from the CLPTM1-p.R568Q group was significantly reduced compared to CLPTM1-WT., Significance: This is the first report of functionally relevant variants within the CLPTM1 gene. Patch-clamp recordings showed that these de novo CLPTM1 variants reduce GABA A R currents and charge transfer, which should promote excitation and hypersynchronous activity. This study may provide insights into the molecular mechanisms of the CLPTM1 variants underlying the patients' phenotypes, as well as for exploring potential therapeutic targets for epilepsy., (© 2023 International League Against Epilepsy.)

We investigate the effect of the adoption of electric vehicles (EVs) on CO 2 emissions using spatial econometric models and have three findings. First, there are spatial spillover effects of EV adoption on CO 2 emissions, implying that the CO 2 mitigation of a city depends on local sales of EVs and sales of EVs in neighboring cities. A 1% increase in the sale of EVs in a city can reduce CO 2 emissions locally by 0.096% and by 0.087% in a nearby city. Second, EVs indirectly impact CO 2 emissions through the substitution effect, energy consumption effect, and technological effect. The overall impact of EV adoption on CO 2 emissions is negative. Finally, we demonstrate the moderating effect of urban energy structure on EVs' CO 2 emissions mitigation. A 1% increase in the proportion of renewable energy generation increases the decarbonization of EVs by 0.036%. These findings provide policy implications for the coordinated development of EV market and energy system., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

N-methyl-D-aspartate receptors (NMDARs) are ligand-gated ionotropic glutamate receptors that mediate a calcium-permeable component to fast excitatory neurotransmission. NMDARs are heterotetrameric assemblies of two obligate GluN1 subunits (GRIN1) and two GluN2 subunits (GRIN2A-GRIN2D). Sequencing data shows that 43% (297/679) of all currently known NMDAR disease-associated genetic variants are within the GRIN2A gene, which encodes the GluN2A subunit. Here, we show that unlike missense GRIN2A variants, individuals affected with disease-associated null GRIN2A variants demonstrate a transient period of seizure susceptibility that begins during infancy and diminishes near adolescence. We show increased circuit excitability and CA1 pyramidal cell output in juvenile mice of both Grin2a +/- and Grin2a -/- mice. These alterations in somatic spiking are not due to global upregulation of most Grin genes (including Grin2b). Deeper evaluation of the developing CA1 circuit led us to uncover age- and Grin2a gene dosing-dependent transient delays in the electrophysiological maturation programs of parvalbumin (PV) interneurons. We report that Grin2a +/+ mice reach PV cell electrophysiological maturation between the neonatal and juvenile neurodevelopmental timepoints, with Grin2a +/- mice not reaching PV cell electrophysiological maturation until preadolescence, and Grin2a -/- mice not reaching PV cell electrophysiological maturation until adulthood. Overall, these data may represent a molecular mechanism describing the transient nature of seizure susceptibility in disease-associated null GRIN2A patients., (© 2023. Springer Nature Limited.)

Advances in sequencing technology have generated a large amount of genetic data from patients with neurological conditions. These data have provided diagnosis of many rare diseases, including a number of pathogenic de novo missense variants in GRIN genes encoding N-methyl-d-aspartate receptors (NMDARs). To understand the ramifications for neurons and brain circuits affected by rare patient variants, functional analysis of the variant receptor is necessary in model systems. For NMDARs, this functional analysis needs to assess multiple properties in order to understand how variants could impact receptor function in neurons. One can then use these data to determine whether the overall actions will increase or decrease NMDAR-mediated charge transfer. Here, we describe an analytical and comprehensive framework by which to categorize GRIN variants as either gain-of-function (GoF) or loss-of-function (LoF) and apply this approach to GRIN2B variants identified in patients and the general population. This framework draws on results from six different assays that assess the impact of the variant on NMDAR sensitivity to agonists and endogenous modulators, trafficking to the plasma membrane, response time course and channel open probability. We propose to integrate data from multiple in vitro assays to arrive at a variant classification, and suggest threshold levels that guide confidence. The data supporting GoF and LoF determination are essential to assessing pathogenicity and patient stratification for clinical trials as personalized pharmacological and genetic agents that can enhance or reduce receptor function are advanced. This approach to functional variant classification can generalize to other disorders associated with missense variants., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Subunit-selective inhibition of N -methyl-d-aspartate receptors (NMDARs) is a promising therapeutic strategy for several neurological disorders, including epilepsy, Alzheimer's and Parkinson's disease, depression, and acute brain injury. We previously described the dihydroquinoline-pyrazoline (DQP) analogue 2a ( DQP-26 ) as a potent NMDAR negative allosteric modulator with selectivity for GluN2C/D over GluN2A/B. However, moderate (<100-fold) subunit selectivity, inadequate cell-membrane permeability, and poor brain penetration complicated the use of 2a as an in vivo probe. In an effort to improve selectivity and the pharmacokinetic profile of the series, we performed additional structure-activity relationship studies of the succinate side chain and investigated the use of prodrugs to mask the pendant carboxylic acid. These efforts led to discovery of the analogue ( S )-(-)- 2i , also referred to as ( S )-(-)- DQP-997 - 74 , which exhibits >100- and >300-fold selectivity for GluN2C- and GluN2D-containing NMDARs (IC 50 0.069 and 0.035 μM, respectively) compared to GluN2A- and GluN2B-containing receptors (IC 50 5.2 and 16 μM, respectively) and has no effects on AMPA, kainate, or GluN1/GluN3 receptors. Compound ( S )-(-)- 2i is 5-fold more potent than ( S )- 2a . In addition, compound 2i shows a time-dependent enhancement of inhibitory actions at GluN2C- and GluN2D-containing NMDARs in the presence of the agonist glutamate, which could attenuate hypersynchronous activity driven by high-frequency excitatory synaptic transmission. Consistent with this finding, compound 2i significantly reduced the number of epileptic events in a murine model of tuberous sclerosis complex (TSC)-induced epilepsy that is associated with upregulation of the GluN2C subunit. Thus, 2i represents a robust tool for the GluN2C/D target validation. Esterification of the succinate carboxylate improved brain penetration, suggesting a strategy for therapeutic development of this series for NMDAR-associated neurological conditions.

This paper uses the China Family Panel Studies' micro-level data and the ordered logit model to study intergenerational transmission of education and examines whether the nine-year compulsory schooling system affects equity in education. The results show that when parents have higher educational attainments, their children will have higher educational attainments. Full-sample results show that when the mother has higher education, the probability that her children have higher education increases by 7.97%, whereas for the sub-sample after the compulsory schooling policy carried out, the probability increases by 22.42%. We find that the compulsory schooling system strengthens intergenerational transmission of education in the level of higher education. An implication is that the compulsory schooling system may promote equity in compulsory education but does not promote equity in higher education., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

The short pre-M1 helix within the S1-M1 linker (also referred to as the pre-M1 linker) between the agonist-binding domain (ABD, S1) and the M1 transmembrane helix of the NMDA receptor (NMDAR) is devoid of missense variants within the healthy population but is a locus for de novo pathogenic variants associated with neurological disorders. Several de novo variants within this helix have been identified in patients presenting early in life with intellectual disability, developmental delay, and/or epilepsy. In this study, we evaluated functional properties for twenty variants within the pre-M1 linker in GRIN1, GRIN2A, and GRIN2B genes, including six novel missense variants. The effects of pre-M1 variants on agonist potency, sensitivity to endogenous allosteric modulators, response time course, channel open probability, and surface expression were assessed. Our data indicated that virtually all of the variants evaluated altered channel function, and multiple variants had profound functional consequences, which may contribute to the neurological conditions in the patients harboring the variants in this region. These data strongly suggest that the residues within the pre-M1 helix play a key role in channel gating and are highly intolerant to genetic variation., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

N-methyl-D-aspartate receptors (NMDARs) play vital roles in normal brain functions (i.e., learning, memory, and neuronal development) and various neuropathological conditions, such as epilepsy, autism, Parkinson's disease, Alzheimer's disease, and traumatic brain injury. Endogenous neuroactive steroids such as 24(S)-hydroxycholesterol (24(S)-HC) have been shown to influence NMDAR activity, and positive allosteric modulators (PAMs) derived from 24(S)-hydroxycholesterol scaffold can also enhance NMDAR function. This study describes the structural determinants and mechanism of action for 24(S)-hydroxycholesterol and two novel synthetic analogs (SGE-550 and SGE-301) on NMDAR function. We also show that these agents can mitigate the altered function caused by a set of loss-of-function missense variants in NMDAR GluN subunit-encoding GRIN genes associated with neurological and neuropsychiatric disorders. We anticipate that the evaluation of novel neuroactive steroid NMDAR PAMs may catalyze the development of new treatment strategies for GRIN-related neuropsychiatric conditions., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The purpose of this study was to investigate the effect of ultrasound-assisted enzymolysis on modified solubilization of yeast β-glucan and its related mechanism. The depolymerization effects of this system on the physicochemical properties and structural features of the degraded fragments were studied systematically. The structure and physicochemical properties of the samples showed that the solubility of yeast β-glucan achieved 75.35 % after modification; and ultrasonic enzymatic enhanced the degradation efficiency. The yeast β-glucan obtained after solubilization and modification owned better antioxidant activities. The yeast β-glucan particles become obviously smaller, sparsely dispersed in the aqueous solution and the stability was improved. In addition, the hydrogen bonds in yeast β-glucan native triple helix structure were partially broken. Moreover, the disruption of yeast β-glucan's original structure made it decreased thermostability and easier to dissolve in water. The atomic force microscope (AFM) imaging directly verified the branched-chain morphology of yeast β-glucan and the small-strand degradation fragments. Therefore, this research can provide a feasible and effective approach for improving solubility of water-insoluble yeast β-glucan to enlarge its food and biomedical applications., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

N-methyl-D-aspartate receptors (NMDARs) are tetrameric assemblies of two glutamate N-methyl-D-aspartate receptor subunits, GluN1 and two GluN2, that mediate excitatory synaptic transmission in the central nervous system. Four genes ( GRIN2A-D ) encode four distinct GluN2 subunits (GluN2A-D). Thus, NMDARs can be diheteromeric assemblies of two GluN1 plus two identical GluN2 subunits, or triheteromeric assemblies of two GluN1 subunits plus two different GluN2 subunits. An increasing number of de novo GRIN variants have been identified in patients with neurologic conditions and with GRIN2A and GRIN2B harboring the vast majority (> 80%) of variants in these cases. These variants produce a wide range of effects on NMDAR function depending upon its subunit subdomain location and additionally on the subunit composition of diheteromeric versus triheteromeric NMDARs. Increasing evidence implicates triheteromeric GluN1/GluN2A/GluN2B receptors as a major component of the NMDAR pool in the adult cortex and hippocampus. Here, we explore the ability of GluN2A- and GluN2B-selective inhibitors to reduce excess current flow through triheteromeric GluN1/GluN2A/GluN2B receptors that contain one copy of GRIN2A or GRIN2B gain-of-function variants. Our data reveal a broad range of sensitivities for variant-containing triheteromeric receptors to subunit-selective inhibitors, with some variants still showing strong sensitivity to inhibitors, whereas others are relatively insensitive. Most variants, however, retain sensitivity to non-selective channel blockers and the competitive antagonist D-(-)-2-amino-5-phosphonopentanoic acid. These results suggest that with comprehensive analysis, certain disease-related GRIN2A and GRIN2B variants can be identified as potential targets for subunit-selective modulation and potential therapeutic gain. SIGNIFICANCE STATEMENT: Triheteromeric NMDA receptors that contain one copy each of the GluN2A and GluN2B subunits show intermediate sensitivity to GluN2A- and GluN2B-selective inhibitors, making these compounds candidates for attenuating overactive, GRIN variant-containing NMDA receptors associated with neurological conditions. We show that functional evaluation of variant properties with inhibitor pharmacology can support selection of a subset of variants for which GluN2 subunit-selective agents remain effective inhibitors of variant-containing triheteromeric NMDA receptors., (Copyright © 2022 by The American Society for Pharmacology and Experimental Therapeutics.)

Bacterial cellulose (BC)-derived materials are given significant attention due to their porous fibrous texture, high crystallinity and extraordinary physico-mechanical properties. The main reason for the restricted use of BC is its high production cost. To reduce the production cost, the suitability of pear residue for the production of BC and pear vinegar was investigated. Komagataeibacter rhaeticus and Komagataeibacter intermedius with high fermentation ability screened from the surface of vinegar film of millet fermentation were used to produce BC and pear vinegar simultaneously. Through response surface optimization, the maximum yield of BC from pear residue medium was 10.94 ± 0.42 g/L, which was higher than the synthesis medium generally used for Acetobacter strains. When pear residue medium was incubated at 30 °C for 7 days, the contents of total acid and soluble solids were greater than 0.3 g/100 mL and 3%, respectively, which met the standard requirements for fruit vinegar. The flavour components of pear vinegar were determined using gas chromatography-mass spectrometry. The pear vinegar showed similar flavour characteristics to conventional fruit vinegar. This research not only solved the utilization of agricultural resources but also avoided the discharge of waste liquid when producing BC. In addition, a more environmentally friendly and less expensive way to produce BC and pear vinegar was achieved., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Considerable genetic variation of N-methyl-d-aspartate receptors (NMDARs) has recently become apparent, with many hundreds of de novo variants identified through widely available clinical genetic testing. Individuals with GRIN variants present with neurological conditions such as epilepsy, autism, intellectual disability (ID), movement disorders, schizophrenia and behavioral disorders. Determination of the functional consequence of genetic variation for NMDARs should lead to precision therapeutics. Furthermore, genetic animal models harboring human variants have the potential to reveal mechanisms that are shared among different neurological conditions, providing strategies that may allow treatment of individuals who are refractory to therapy. Preclinical studies in animal models and small open label trials in humans support this idea. However, additional functional data for variants and animal models corresponding to multiple individuals with the same genotype are needed to validate this approach and to lead to thoughtfully designed, randomized, placebo-controlled clinical trials, which could provide data in order to determine safety and efficacy of potential precision therapeutics., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Many physiologic effects of l-glutamate, the major excitatory neurotransmitter in the mammalian central nervous system, are mediated via signaling by ionotropic glutamate receptors (iGluRs). These ligand-gated ion channels are critical to brain function and are centrally implicated in numerous psychiatric and neurologic disorders. There are different classes of iGluRs with a variety of receptor subtypes in each class that play distinct roles in neuronal functions. The diversity in iGluR subtypes, with their unique functional properties and physiologic roles, has motivated a large number of studies. Our understanding of receptor subtypes has advanced considerably since the first iGluR subunit gene was cloned in 1989, and the research focus has expanded to encompass facets of biology that have been recently discovered and to exploit experimental paradigms made possible by technological advances. Here, we review insights from more than 3 decades of iGluR studies with an emphasis on the progress that has occurred in the past decade. We cover structure, function, pharmacology, roles in neurophysiology, and therapeutic implications for all classes of receptors assembled from the subunits encoded by the 18 ionotropic glutamate receptor genes. SIGNIFICANCE STATEMENT: Glutamate receptors play important roles in virtually all aspects of brain function and are either involved in mediating some clinical features of neurological disease or represent a therapeutic target for treatment. Therefore, understanding the structure, function, and pharmacology of this class of receptors will advance our understanding of many aspects of brain function at molecular, cellular, and system levels and provide new opportunities to treat patients., (U.S. Government work not protected by U.S. copyright.)

N -Methyl-D-aspartate receptors (NMDARs) are highly expressed in brain and play important roles in neurodevelopment and various neuropathologic conditions. Here, we describe a new phenotype in an individual associated with a novel de novo deleterious variant in GRIN1 (c.1595C>A, p.Pro532His). The clinical phenotype is characterized with developmental encephalopathy, striking stimulus-sensitive myoclonus, and frontal lobe and frontal white matter hypoplasia, with no apparent seizures detected. NMDARs that contained the P532H within the glycine-binding domain of GluN1 with either the GluN2A or GluN2B subunits were evaluated for changes in their pharmacological and biophysical properties, which surprisingly revealed only modest changes in glycine potency but a significant decrease in glutamate potency, an increase in sensitivity to endogenous zinc inhibition, a decrease in response to maximally effective concentrations of agonists, a shortened synaptic-like response time course, a decreased channel open probability, and a reduced receptor cell surface expression. Molecule dynamics simulations suggested that the variant can lead to additional interactions across the dimer interface in the agonist-binding domains, resulting in a more open GluN2 agonist-binding domain cleft, which was also confirmed by single-molecule fluorescence resonance energy transfer measurements. Based on the functional deficits identified, several positive modulators were evaluated to explore potential rescue pharmacology., Competing Interests: HY is PI on a research grant from Sage Therapeutics to Emory University School of Medicine. ST is PI on research grants from Janssen and Biogen to Emory University School of Medicine, is a member of the SAB for Sage Therapeutics and Eumentis, Inc., is co-founder of NeurOp Inc. and Agrithera Inc., and receives royalties for software. ST and HY are co-inventors on Emory-owned Intellectual Property that includes allosteric modulators of NMDA receptor function. SM owns shares in NeurOp. Inc. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Zhang, Tang, Bhatia, Xu, Paudyal, Liu, Kim, Song, XiangWei, Shaulsky, Myers, Dobyns, Jayaraman, Traynelis, Yuan and Bozarth.)

Objective: Genetic variants in the GRIN genes that encode N-methyl-D-aspartate receptor (NMDAR) subunits have been identified in various neurodevelopmental disorders, including epilepsy. We identified a GRIN1 variant from an individual with early-onset epileptic encephalopathy, evaluated functional changes to NMDAR properties caused by the variant, and screened FDA-approved therapeutic compounds as potential treatments for the patient., Methods: Whole exome sequencing identified a missense variant in GRIN1. Electrophysiological recordings were made from Xenopus oocytes and transfected HEK cells to determine the NMDAR biophysical properties as well as the sensitivity to agonists and FDA-approved drugs that inhibit NMDARs. A beta-lactamase reporter assay in transfected HEK cells evaluated the effects of the variant on the NMDAR surface expression., Results: A recurrent de novo missense variant in GRIN1 (c.1923G>A, p.Met641Ile), which encodes the GluN1 subunit, was identified in a pediatric patient with drug-resistant seizures and early-onset epileptic encephalopathy. In vitro analysis indicates that GluN1-M641I containing NMDARs showed enhanced agonist potency and reduced Mg 2+ block, which may be associated with the patient's phenotype. Results from screening FDA-approved drugs suggested that GluN1-M641I containing NMDARs are more sensitive to the NMDAR channel blockers memantine, ketamine, and dextromethorphan compared to the wild-type receptors. The addition of memantine to the seizure treatment regimen significantly reduced the patient's seizure burden., Interpretation: Our finding contributes to the understanding of the phenotype-genotype correlations of patients with GRIN1 gene variants, provides a molecular mechanism underlying the actions of this variant, and explores therapeutic strategies for treating GRIN1-related neurological conditions., (© 2021 The Authors. Annals of Clinical and Translational Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

NMDA receptors are ligand-gated ion channels that mediate a slow, Ca 2+ -permeable component of excitatory synaptic currents. These receptors are involved in several important brain functions, including learning and memory, and have also been implicated in neuropathological conditions and acute central nervous system injury, which has driven therapeutic interest in their modulation. The EU1794 series of positive and negative allosteric modulators of NMDA receptors has structural determinants of action near the preM1 helix that is involved in channel gating. Here, we describe the effects of the negative allosteric modulator EU1794-4 on GluN1/GluN2A channels studied in excised outside-out patches. Coapplication of EU1794-4 with a maximally effective concentration of glutamate and glycine increases the fraction of time the channel is open by nearly 1.5-fold, yet reduces single-channel conductance by increasing access of the channel to several subconductance levels, which has the net overall effect of reducing the macroscopic current. The lack of voltage-dependence of negative modulation suggests this is unrelated to a channel block mechanism. As seen with other NMDA receptor modulators that reduce channel conductance, EU1794-4 also reduces the Ca 2+ permeability relative to monovalent cations of GluN1/GluN2A receptors. We conclude that EU1794-4 is a prototype for a new class of NMDA receptor negative allosteric modulators that reduce both the overall current that flows after receptor activation and the flux of Ca 2+ ion relative to monovalent cations. SIGNIFICANCE STATEMENT: NMDA receptors are implicated in many neurological conditions but are challenging to target given their ubiquitous expression. Several newly identified properties of the negative allosteric modulator EU1794-4, including reducing Ca 2+ flux through NMDA receptors and attenuating channel conductance, explain why this modulator reduces but does not eliminate NMDA receptor function. A modulator with these properties could have therapeutic advantages for indications in which attenuation of NMDA receptor function is beneficial, such as neurodegenerative disease and acute injury., Competing Interests: The opinions expressed in this paper are those of the authors and do not necessarily reflect the views of the funding agency. S.F.T. is a PI on research grants from Allergan, Biogen, and Janssen to Emory University; is a paid consultant for Janssen; is a member of the SAB for Sage Therapeutics, Eumentis, the GRIN2B Foundation, and the CureGRIN Foundation; is cofounder of NeurOp Inc. and Agrithera Inc.; and has received licensing fees and royalties from Emory. D.C.L. is on the Board of Directors of NeurOp Inc. S.F.T., B.K., H.Y., and D.C.L. are coinventors on Emory University–owned intellectual property that includes allosteric modulators of glutamate receptor function. H.Y. is a PI on research grant from Sage Therapeutics to Emory University., (Copyright © 2021 by The American Society for Pharmacology and Experimental Therapeutics.)

A promising bifunctional catalyst integrating Co@NC units and porous structure carbon nanosheets (Co@NC/NCNS) is in situ prepared by the calcination and subsequent acid etching of a mixture containing metal alkoxide and melamine. Benefiting from the synergism among the active sites and porous structure, the optimal Co@NC/NCNS-800 exhibits superior activity for the ORR/OER.

N-methyl-d-aspartate receptors (NMDARs) mediate a slow component of excitatory synaptic transmission that plays important roles in normal brain function and development. A large number of disease-associated variants in the GRIN gene family encoding NMDAR GluN subunits have been identified in patients with various neurological and neuropsychiatric disorders. Many of these variants reduce the function of NMDARs by a range of different mechanisms, including reduced glutamate potency, reduced glycine potency, accelerated deactivation time course, decreased surface expression, and/or reduced open probability. We have evaluated whether three positive allosteric modulators of NMDAR receptor function (24(S)-hydroxycholesterol, pregnenolone sulfate, tobramycin) and three co-agonists (d-serine, l-serine, and d-cycloserine) can mitigate the diminished function of NMDARs harboring GRIN variants. We examined the effects of these modulators on NMDARs that contained 21 different loss-of-function variants in GRIN1, GRIN2A, or GRIN2B, identified in patients with epilepsy, intellectual disability, autism, and/or movement disorders. For all variants, some aspect of the reduced function was partially restored. Moreover, some variants showed enhanced sensitivity to positive allosteric modulators compared to wild type receptors. These results raise the possibility that enhancement of NMDAR function by positive allosteric modulators may be a useful therapeutic strategy., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

NMDA receptors are ligand-gated ion channels that mediate excitatory neurotransmission. Most native NMDA receptors are tetrameric assemblies of two glycine-binding GluN1 and two glutamate-binding GluN2 subunits. Co-assembly of the glycine-binding GluN1 with glycine-binding GluN3 subunits (GluN3A-B) creates glycine activated receptors that possess strikingly different functional and pharmacological properties compared to GluN1/GluN2 NMDA receptors. The role of GluN1/GluN3 receptors in neuronal function remains unknown, in part due to lack of pharmacological tools with which to explore their physiological roles. We have identified the negative allosteric modulator EU1180-438, which is selective for GluN1/GluN3 receptors over GluN1/GluN2 NMDA receptors, AMPA, and kainate receptors. EU1180-438 is also inactive at GABA, glycine, and P2X receptors, but displays inhibition of some nicotinic acetylcholine receptors. Furthermore, we demonstrate that EU1180-438 produces robust inhibition of glycine-activated current responses mediated by native GluN1/GluN3A receptors in hippocampal CA1 pyramidal neurons. EU1180-438 is a non-competitive antagonist with activity that is independent of membrane potential (i.e. voltage-independent), glycine concentration, and extracellular pH. Non-stationary fluctuation analysis of neuronal current responses provided an estimated weighted mean unitary conductance of 6.1 pS for GluN1/GluN3A channels, and showed that EU1180-438 has no effect on conductance. Site-directed mutagenesis suggests that structural determinants of EU1180-438 activity reside near a short pre-M1 helix that lies parallel to the plane of the membrane below the agonist binding domain. These findings demonstrate that structural differences between GluN3 and other glutamate receptor subunits can be exploited to generate subunit-selective ligands with utility in exploring the roles GluN3 in neuronal function., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Glutamate receptors are essential ligand-gated ion channels in the central nervous system that mediate excitatory synaptic transmission in response to the release of glutamate from presynaptic terminals. The structural and biophysical basis underlying the function of these receptors has been studied for decades by a wide range of approaches. However recent structural, pharmacological and genetic studies have provided new insight into the regions of this protein that are critical determinants of receptor function. Lack of variation in specific areas of the protein amino acid sequences in the human population has defined three regions in each receptor subunit that are under selective pressure, which has focused research efforts and driven new hypotheses. In addition, these three closely positioned elements reside near a cavity that is shown by multiple studies to be a likely site of action for allosteric modulators, one of which is currently in use as an FDA-approved anticonvulsant. These structural elements are capable of controlling gating of the pore, and appear to permit some modulators bound within the cavity to also alter permeation properties. This creates a new precedent whereby features of the channel pore can be modulated by exogenous drugs that bind outside the pore. The convergence of structural, genetic, biophysical and pharmacological approaches is a powerful means to gain insight into the complex biological processes defined by neurotransmitter receptor function., (© 2020 The Authors. The Journal of Physiology © 2020 The Physiological Society.)

Background: Hemizygous mutations in GRIA3 encoding the GluA3 subunit of the amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor are known to be associated with neurodevelopmental disorders, including intellectual disability, hypotonia, an autism spectrum disorder, sleep disturbances, and epilepsy in males., Objective: To describe a new and consistent phenotype in 4 affected male patients associated with an undescribed deleterious variant in GRIA3., Methods: We evaluated a large French family in which segregate a singular phenotype according to an apparent X-linked mode of inheritance. Molecular analyses using next generation sequencing and in vitro functional studies using 2-electrode voltage clamp recordings on Xenopus laevis oocytes and a β-lactamase reporter assay in transfected human embryonic kidney (HEK293) cells were performed., Results: In addition to mild intellectual disability and dysarthria, affected patients presented a tightly consistent early-onset movement disorder combining an exaggerated startle reflex with generalized chorea and multifocal myoclonus. The unreported GRIA3 missense variant c.2477G > A; p.(Gly826Asp) affecting the fourth transmembrane domain of the protein was identified in index patients and their unaffected mothers. Functional studies revealed that variant receptors show decreased current response evoked by agonist (ie, kainic acid and glutamate) and reduced expression on the cell surface in favor of pathogenicity by a loss-of-function mechanism., Conclusions: Taken together, our results suggest that apart from known GRIA3-related disorders, an undescribed mutation-specific singular movement disorder does exist. We thus advocate considering GRIA3 mutations in the differential diagnosis of hyperekplexia and generalized chorea with myoclonus. © 2020 International Parkinson and Movement Disorder Society., (© 2020 International Parkinson and Movement Disorder Society.)

NMDA receptors play crucial roles in excitatory synaptic transmission. Rare variants in GRIN2A encoding the GluN2A subunit are associated with a spectrum of disorders, ranging from mild speech and language delay to intractable neurodevelopmental disorders, including but not limited to developmental and epileptic encephalopathy. A de novo missense variant, p.Ser644Gly, was identified in a child with this disorder, and Grin2a knock-in mice were generated to model and extend understanding of this intractable childhood disease. Homozygous and heterozygous mutant mice exhibited altered hippocampal morphology at 2 weeks of age, and all homozygotes exhibited lethal tonic-clonic seizures by mid-third week. Heterozygous adults displayed susceptibility to induced generalized seizures, hyperactivity, repetitive and reduced anxiety behaviours, plus several unexpected features, including significant resistance to electrically-induced limbic seizures and to pentylenetetrazole induced tonic-clonic seizures. Multielectrode recordings of neuronal networks revealed hyperexcitability and altered bursting and synchronicity. In heterologous cells, mutant receptors had enhanced NMDA receptor agonist potency and slow deactivation following rapid removal of glutamate, as occurs at synapses. NMDA receptor-mediated synaptic currents in heterozygous hippocampal slices also showed a prolonged deactivation time course. Standard anti-epileptic drug monotherapy was ineffective in the patient. Introduction of NMDA receptor antagonists was correlated with a decrease in seizure burden. Chronic treatment of homozygous mouse pups with NMDA receptor antagonists significantly delayed the onset of lethal seizures but did not prevent them. These studies illustrate the power of using multiple experimental modalities to model and test therapies for severe neurodevelopmental disorders, while revealing significant biological complexities associated with GRIN2A developmental and epileptic encephalopathy., (© The Author(s) (2020). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Allosteric modulators of ion channels typically alter the transitions rates between conformational states without changing the properties of the open pore. Here we describe a new class of positive allosteric modulators of N-methyl D-aspartate receptors (NMDARs) that mediate a calcium-permeable component of glutamatergic synaptic transmission and play essential roles in learning, memory and cognition, as well as neurological disease. EU1622-14 increases agonist potency and channel-open probability, slows receptor deactivation and decreases both single-channel conductance and calcium permeability. The unique functional selectivity of this chemical probe reveals a mechanism for enhancing NMDAR function while limiting excess calcium influx, and shows that allosteric modulators can act as biased modulators of ion-channel permeation.

Background: Chronic pain usually accompanied by tissue damage and inflammation. However, the pathogenesis of chronic pain remains unclear., Methods: We investigated the role of nerve growth factor (NGF) in chronic inflammatory pain induced by complete Freund's adjuvant (CFA), explored the methylation status of CpG islands in the promoter region of the NGF gene, and clarified the function and mechanism of C/EBPα-NGF signaling pathway from epigenetic perspective in the chronic inflammatory pain model., Results: CFA induced significant hyperalgesia and continuous upregulation of NGF mRNA and protein levels in the L4-6 dorsal root ganglions (DRGs) in rats. Hypomethylation of CpG islands occurred in the NGF gene promoter region after CFA treatment. At the same time, the miR-29b expression level was significantly increased, while the DNA methyltransferase 3b (DNMT3b) level reduced significantly. Moreover, CFA treatment promoted binding of C/EBPα to the NGF gene promoter region and C/EBPα siRNA treatment obviously decreased expression of NGF levels and also alleviate inflammatory hyperalgesia significantly in rats., Conclusion: Collectively, the results indicated that CFA leads to the upregulation of miR-29b level, which represses the expression of DNMT3b, enhances the demethylation of the NGF gene promoter region, and promotes the binding of C/EBPα with the NGF gene promoter, thus results in the upregulation of NGF gene expression and maintenance of chronic inflammatory pain.

N-methyl-d-aspartate receptors (NMDARs), a subset of ligand-gated ionotropic glutamate receptors, are critical for learning, memory, and neuronal development. However, when NMDAR subunits are mutated, a host of neuropathological conditions can occur, including epilepsy. Recently, genetic variation within the GRIN2D gene, which encodes the GluN2D subunit of the NMDAR, has been associated with a set of early-onset neurological diseases, notably developmental and epileptic encephalopathy (DEE). Importantly, patients with GRIN2D variants are largely refractory to conventional anti-epileptic drug (AED) treatment, highlighting the need to further understand the distinctive characteristics of GluN2D in neurological and pathological functions. In this review, we first summarize GluN2D's unique spatial and temporal expression patterns, electrophysiological profiles, and contributions to both pre- and postsynaptic signaling. Next, we review thirteen unique case studies from DEE patients harboring ten different causal GRIN2D variants. These patients are highly heterogenous, manifesting multiple seizure types, electroencephalographic recordings, and neurological and developmental outcomes. Lastly, this review concludes by highlighting the difficulty in treating patients with DEE-associated GRIN2D variants, and stresses the need for selective therapeutic agents delivered within a precise time window., Competing Interests: Declaration of competing interest None of the authors have any conflicts of interest to disclose., (Copyright © 2019 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.)

β-Glucan exhibits many biological activities and functions such as stimulation of the immune system and anti-inflammatory, anti-microbial, anti-infective, anti-viral, anti-tumor, anti-oxidant, anti-coagulant, cholesterol-lowering, radio protective, and wound healing effects. It has a wide variety of uses in pharmaceutical, cosmetic, and chemical industries as well as in food processing units. However, due to its dense triple helix structure, formed by the interaction of polyhydroxy groups in the β-d-glucan molecule, it features poor solubility, which not only constrains its applications, but also inhibits its physiological function in vivo. One aim is to expand the applications for modified β-glucan with potential to prevent disease, various therapeutic purposes and as health-improving ingredients in functional foods and cosmetics. This review introduces the major modification methods required to understand the bioactivity of β-glucan and critically provides a literature survey on the structural features of this molecule and reported biological activity. We also discuss a new method to create novel opportunities to exploit maximally various properties of β-glucan, namely ultrasound-assisted enzymatic modification.

N-methyl-D-aspartate receptors (NMDARs) mediate slow excitatory postsynaptic transmission in the central nervous system, thereby exerting a critical role in neuronal development and brain function. Rare genetic variants in the GRIN genes encoding NMDAR subunits segregated with neurological disorders. Here, we summarize the clinical presentations for 18 patients harboring 12 de novo missense variants in GRIN1, GRIN2A, and GRIN2B that alter residues in the M2 re-entrant loop, a region that lines the pore and is intolerant to missense variation. These de novo variants were identified in children with a set of neurological and neuropsychiatric conditions. Evaluation of the receptor cell surface expression, pharmacological properties, and biophysical characteristics show that these variants can have modest changes in agonist potency, proton inhibition, and surface expression. However, voltage-dependent magnesium inhibition is significantly reduced in all variants. The NMDARs hosting a single copy of a mutant subunit showed a dominant reduction in magnesium inhibition for some variants. These variant NMDARs also show reduced calcium permeability and single-channel conductance, as well as altered open probability. The data suggest that M2 missense variants increase NMDAR charge transfer in addition to varied and complex influences on NMDAR functional properties, which may underlie the patients' phenotypes., (© 2019 Wiley Periodicals, Inc.)

Background: Spinal cord injury (SCI) is a common type of injury, and about half of patients affected by SCI will suffer from neuropathic pain within a year after injury. However, the treatment effect of neuropathic pain is far from satisfactory. Our study attempted to reveal whether salvianolic acid B (SalB) could relieve the neuropathic pain caused by SCI in mice by inhibiting the Toll-like receptor 4 (TLR4)/Myeloid differentiation factor 88 (MyD88) pathway., Methods: The mice were randomly divided into a sham group, model group, high-dose treatment group, and low-dose treatment group. The high- and low-dose groups received varying doses of SalB after modeling., Results: The increase of pain sensitivity was evaluated by detecting paw withdrawal mechanical threshold and withdrawal thermal latency. Messenger RNA and protein expression levels of TLR4 and myD88 were detected by using quantitative reverse-transcription polymerase chain reaction and western blot, respectively. Compared with the model group, there was a significant reduction in paw withdrawal mechanical threshold and withdrawal thermal latency after SalB treatment., Conclusions: SalB reduced the release of tumor necrosis factor-α and substance P by inhibiting the TLR4/MyD88 pathway in the SCI mouse model. This not only resulted in lower pain, but also contributed to long-term relief of mechanical hyperalgesia., (Copyright © 2019. Published by Elsevier Inc.)

Rapid advances in sequencing technology have led to an explosive increase in the number of genetic variants identified in patients with neurological disease and have also enabled the assembly of a robust database of variants in healthy individuals. A surprising number of variants in the GRIN genes that encode N -methyl-D-aspartate (NMDA) glutamatergic receptor subunits have been found in patients with various neuropsychiatric disorders, including autism spectrum disorders, epilepsy, intellectual disability, attention-deficit/hyperactivity disorder, and schizophrenia. This review compares and contrasts the available information describing the clinical and functional consequences of genetic variations in GRIN2A and GRIN2B. Comparison of clinical phenotypes shows that GRIN2A variants are commonly associated with an epileptic phenotype but that GRIN2B variants are commonly found in patients with neurodevelopmental disorders. These observations emphasize the distinct roles that the gene products serve in circuit function and suggest that functional analysis of GRIN2A and GRIN2B variation may provide insight into the molecular mechanisms, which will allow more accurate subclassification of clinical phenotypes. Furthermore, characterization of the pharmacological properties of variant receptors could provide the first opportunity for translational therapeutic strategies for these GRIN -related neurological and psychiatric disorders., Competing Interests: Competing interests: SFT is PI on a research grant from Allergan and Janssen and Emory University School of Medicine, is a member of the SAB for Sage Therapeutics, is co-founder of NeurOp Inc, and receives royalties for software. SFT and SJM are co-inventors on Emory-owned Intellectual Property that includes allosteric modulators of NMDAR function.No competing interests were disclosed.No competing interests were disclosed., (Copyright: © 2019 Myers SJ et al.)

N-methyl d-aspartate receptors are ligand-gated ionotropic receptors mediating a slow, calcium-permeable component of excitatory synaptic transmission in the CNS. Variants in genes encoding NMDAR subunits have been associated with a spectrum of neurodevelopmental disorders. Here we report six novel GRIN2D variants and one previously-described disease-associated GRIN2D variant in two patients with developmental and epileptic encephalopathy. GRIN2D encodes for the GluN2D subunit protein; the GluN2D amino acids affected by the variants in this report are located in the pre-M1 helix, transmembrane domain M3, and the intracellular carboxyl terminal domain. Functional analysis in vitro reveals that all six variants decreased receptor surface expression, which may underline some shared clinical symptoms. In addition the GluN2D(Leu670Phe), (Ala675Thr) and (Ala678Asp) substitutions confer significantly enhanced agonist potency, and/or increased channel open probability, while the GluN2D(Ser573Phe), (Ser1271Phe) and (Arg1313Trp) substitutions result in a mild increase of agonist potency, reduced sensitivity to endogenous protons, and decreased channel open probability. The GluN2D(Ser573Phe), (Ala675Thr), and (Ala678Asp) substitutions significantly decrease current amplitude, consistent with reduced surface expression. The GluN2D(Leu670Phe) variant slows current response deactivation time course and increased charge transfer. GluN2D(Ala678Asp) transfection significantly decreased cell viability of rat cultured cortical neurons. In addition, we evaluated a set of FDA-approved NMDAR channel blockers to rescue functional changes of mutant receptors. This work suggests the complexity of the pathological mechanisms of GRIN2D-mediated developmental and epileptic encephalopathy, as well as the potential benefit of precision medicine., (© The Author(s) (2019). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: MicroRNA can regulate gene expression, and participate in multiple vital activities, such as inflammation, oxidative stress epigenetic modification, cell proliferation, and apoptosis. It plays an important role in the genesis and development of cardiovascular disease. Objective: To assess the role of microRNA-208a in ketamine-induced cardiotoxicity. Methods: All rats were randomly selected into two groups: sham and model groups. After fixed, all rats in the model group was intraperitoneally (IP) injected with 100 mg/kg of ketamine. Heart samples were stained with HE assay. Total RNAs from serum were used to hybridize with the SurePrint G3 Rat Whole Genome GE 8×60 K Microarray G4858A platform. Results: In the rat model with ketamine-induced cardiotoxicity, microRNA-208a expression was increased. Then, over-expression of microRNA-208a increased inflammation and oxidative stress in vitro model. However, down-regulation of microRNA-208a decreased inflammation and oxidative stress in vitro model. Over-expression of microRNA-208a suppressed CHD9 and Notch1, and induced p65 protein expression in vitro model. Overexpression of CHD9 reduced the effects of microRNA-208a on inflammation and oxidative stress in heart cell through Notch/p65 signal pathways. Notch1 activation reduced the effects of microRNA-208a on inflammation and oxidative stress in heart cell through p65 signal pathways. Conclusion: MicroRNA-208a may be a potential biomarker for ketamine-induced cardiotoxicity through inflammation and oxidative stress by Notch/NF-κB signal pathways by CHD9., (© 2019 The Author(s).)