Biology subjects

Venkatesan, S.

Publications and source records attributed to Venkatesan, S..

At least 19 recordsLinked to original sources

bioRxiv2026

Characterization of the Grin1Q536R/+ mouse: a preclinical model for GRIN1-related neurodevelopmental disorder

N-methyl-D-aspartate receptors (NMDARs) are ionotropic glutamate receptors playing critical roles in brain development, synaptic plasticity, and cognition. GRIN1-Related Neurodevelopmental Disorder (GRIN1-NDD) is a rare genetic condition caused by pathogenic variations in the GRIN1 gene, which encodes the obligatory subunit of NMDARs. The spectrum of GRIN1 clinical symptoms is hypothesized to result from the functional consequences that different missense variants have on NMDARs. To investigate the disease mechanism in vivo, we generated a novel heterozygous Grin1Q536R/+ knock-in mouse model that carries the identical variation as an adolescent male patient. We describe the clinical presentation of this patient and conduct comprehensive molecular, morphological, electrophysiological, and behavioural characterization in the juvenile, adult, and aging mice. Compared to wildtype littermates, Grin1Q536R/+ mice displayed reduced whole-cell NMDA-induced currents in cortical pyramidal neurons, and reduced NMDAR-mediated synaptic transmission, decreased long-term potentiation, but intact depotentiation at the hippocampal CA1 synapses. Morphological change was observed in the dentate gyrus region of the Grin1Q536R/+ mice. Behavioral phenotyping revealed age- and sex-dependent differences from controls, including hyperlocomotion, reduced muscle strength, and spatial learning deficits. These phenotypes are in line with the clinical manifestations and the relative disease severity of the male patient. The age-dependent phenotypic shift in Grin1Q536R/+ mice highlights the model's value for investigating GRIN1-NDD disease progression and informing longitudinal monitoring as well as potential therapeutic adjustments with age. Taken together, our findings establish a novel and robust in vivo model for studying NMDAR mechanisms and disease pathology in GRIN1-NDD, while supporting the preclinical development of new therapeutic strategies.

neuroscience↗

bioRxiv2026

Spacing theta-burst stimulation enhances synaptic potentiation in the vulnerable prefrontal cortex

Neuromodulation with intermittent theta-burst stimulation (iTBS) is a clinical treatment for major depression. One postulated mechanism of iTBS is to strengthen the synaptic connections which activate the prefrontal cortex to regulate mood. With ex vivo electrical stimulation and neuronal calcium imaging, we demonstrate that a common, clinical iTBS pattern (600-stimuli, ~3-minutes) reliably strengthens the synaptic recruitment of the adult mouse prefrontal cortex. This synaptic potentiation, however, becomes less reliable in the depressive-like mouse model of prolonged social isolation. To better understand this change, we examine the impact of social isolation on the complex pattern of calcium elevation during clinical iTBS. In social isolation, the calcium peaks rise more prominently, but the induction peak no longer predicts the synaptic potentiation outcome. To better regulate calcium dynamics during induction, we test a paradigm with fewer iTBS episodes, separated by longer intervals. This spaced iTBS (90-stimuli, ~10-minutes) in the adult prefrontal cortex limits calcium elevation during induction and yields reliable long-term potentiation (LTP) following either juvenile- or adult-onset social isolation. This research illustrates new strategies to interrogate and to enhance synaptic plasticity in the vulnerable prefrontal cortex.

neuroscience↗

bioRxiv2026

A consensus atlas of human brain development defines cell type-specific maturation trajectories across the lifespan

Human neurodevelopment is a continuous process that begins prenatally and extends into postnatal life. Current transcriptomic datasets are limited, fragmented across analytical frameworks, precluding comprehensive reconstruction of cellular trajectories linking developmental states to mature cell types. Here we present a consolidated cellular-resolution transcriptomic atlas of human brain development from the onset of neurogenesis to adulthood, covering [~]2.2 million cells from 156 donors across nine studies. All data were reprocessed from raw sequencing reads and annotated within a unified cell-type taxonomy, enabling reliable mapping across the lifespan. Cell types were highly replicable across heterogeneous datasets, enabling us to chart their maturation and cortical layer localization over time. We identify dynamic gene programs predictive of cell-type maturation, validate gene modules tracking known fate transitions, and leverage our atlas scale to characterize rare populations, including microglia. This resource establishes a standardized reference of human brain development and maturation gene modules for future comparisons across model systems, species, and disease states.

neuroscience↗

bioRxiv2026

Nascent protein retention at polysomes reduces kinetic barriers to self-assembly

Living proteomes are necessarily far from equilibrium. It is paradoxical, then, that reducing the translation of new proteins -- which should promote equilibration -- instead prolongs life. We investigated the impact of translational flux to nucleation barriers that preserve the solubility of proteins destined to form amyloids or other assemblies. By manipulating translation initiation rates directly or indirectly, across yeast and human cells, and across a variety of supersaturable proteins, we find that accelerating translation initiation broadly accelerates nucleation irrespective of their global concentrations. We showed that this effect was confined to polysomes and was enhanced by N-terminal placement or other features that retained the nascent aggregating domain at polysomes. Finally, we show that intrinsically disordered regions with high tendencies to self-associate are specifically positioned to do so co-translationally, providing evidence that cotranslational nucleation has shaped proteome evolution.

cell biology↗

bioRxiv2026

A diagnostic plasma omics-biomarker for Alzheimer's disease informed by microglial single-cell transcriptomics: A pilot study

BackgroundThe current biomarker framework for the diagnosis and staging of Alzheimers disease (AD) relies mainly on neuropathological features; thus, its performance for diagnosis is limited prior to the initiation of neurodegeneration. Here, we leveraged transcriptomic data to develop a new framework for omic-informed blood-based diagnostic biomarkers for AD from early-stage. MethodsMicroglial gene expression from single-nucleus (sn)RNA-seq data was analyzed via 6 statistical methods to identify candidate panels of genes predictive of AD. A total of 78 gene panels, 30-2000 genes in size, were selected and evaluated for their ability to distinguish AD patients from controls. Three top-ranked panels of 300, 50 and 30 genes were transferred to blood (monocyte) transcriptomic data obtained from living subjects via a graph-based mapping approach based on optimal transport statistics. ResultsThe 300-panel method resulted in an AUC of 0.7 and moderate accuracy (75%) in classifying AD; however, the accuracy in predicting cognitively normal patients was lower (53%). While the 300 genes provided high accuracy, inspection of the distribution of p values for the gene set revealed that the panel could be greatly reduced in size to capture the most significant differences between AD patients and cognitively normal individuals. The accuracy and specificity of the 50 and 30 panels demonstrated similar AUC values but improved the balance between the prediction of AD patients and normal controls. Specifically, the 50-gene panel resulted in an AUC of 0.7, with 65% AD accuracy and 71% normal accuracy. ConclusionsIntegrating multiomics datasets into the AD biomarker discovery pipeline offers a powerful modality to increase precision and comprehensiveness in AD research and clinical applications.

genomics↗

bioRxiv2026

Intracellular TDP-43 amyloid nucleates from arrested nascent condensates

TDP-43 is a model protein for pathophysiological phase transitions, forming a multitude of intracellular assemblies with different physical properties. Physiological condensation is widely presumed to precede pathological aggregation, but the causal relationships between different modes of assembly in vivo are still unclear. Here we use Distributed Amphifluoric FRET (DAmFRET) and complementary approaches to map the phase space of TDP-43 self-assembly in yeast cells. We discovered that the low-complexity C-terminal domain (CTD) on its own partitions into soluble clusters that dynamically arrest en route to liquid-liquid phase separation. These clusters uniquely supported amyloid formation, and only when templated by pre-existing amyloids of other proteins. Self-interacting modules outside the CTD, whether in the full-length TDP-43, pathological C-terminal fragments, or fusion partners, all suppressed amyloid nucleation. They did this by promoting CTD condensation beyond the arrested state. Stress and cotranslational self-association had the same effect. We leveraged this property of condensation to stop CTD amyloid formation by co-expressing an oligomeric binder in cells. Our findings reveal that TDP-43 amyloid formation occurs only under very specific physical and biological circumstances that present new opportunities for therapeutic control.

biophysics↗

bioRxiv2025

Resource supplementation alters host exposure, susceptibility, and infection dynamics across a diverse parasite community

Resource availability is crucial in shaping exposure and resistance to parasites. Although effects are expected to vary across parasite species, most of our knowledge comes from single-host, single-parasite studies. In a wild wood mouse population (Apodemus sylvaticus), we supplemented dietary resources over 3 years and quantified effects on a diverse parasite community alongside host behaviour and physiology. Resource supplementation had diverse impacts on 12 parasite taxa including positive (3/12), negative (6/12), and null (3/12) results. Supplementation also influenced host biology, with supplemented mice moving less, experiencing higher conspecific densities, improved conditions, and increased reproduction. These findings experimentally demonstrate that resource availability can multifacetedly affect disease dynamics. The complexity likely arises due to combined effects on exposure and susceptibility processes. Our study advances understanding of disease drivers at the human-wild interface and underscores the importance of assessing whole parasite communities to predict responses to changing resource landscapes in the wild.

ecology↗

bioRxiv2025

Environmental drivers of low vaccine responsiveness in a lab-to-wild rodent model

Vaccination is the most effective way to prevent infectious diseases and safeguard public health. Yet, most new vaccines fail in late clinical trials, and even estab-lished ones often underperform in populations apart from those in which they were initially tested. This can lead to reduced vaccine responsiveness, breakthrough infections, and prevent or delay herd immunity. While the causes of vaccine hypore-sponsiveness remain difficult to identify, quantify, and therefore address, numerous reports indicate a predominant role of environmental factors. This has notably been demonstrated by a reduction in the immunogenicity and efficacy of various vaccines when transitioning from urban to rural human populations. Here, we tested whether and, if so, how the environment can cause vaccine hyporesponsive-ness. We hypothesised that if the leading causes of vaccine hyporesponsiveness were environmental, then the reduced efficacy would be exacerbated when indi-viduals are under nutritional stress; specifically predicting that high quality diet supplementation would increase vaccine responsiveness. Finally, we predicted that parasitic helminth infection, which are more common in rural populations, would degrade vaccine responsiveness, e.g. due to their ability to suppress host immunity, and that anthelmintic treatment could rescue vaccine responsiveness in infected individuals. To test these hypotheses, we coupled lab and field experiments with structural causal modelling, and measured antibody responses of paired conspecific cohorts of laboratory-reared and wild wood mice (Apodemus sylvaticus) to a single or two doses of diphtheria toxoid vaccine formulated with alum; with and without diet supplementation. We found that vaccine-specific IgG1 antibodies were [~]47% lower in the wild wood mice compared to the laboratory reared population. We also demonstrate that, across both habitats (wild and lab), substantial variation in vaccine responsiveness was caused by diet. However, contrary to our predictions, this high quality dietary supplementation resulted in lower vaccine responsiveness. Further, once the effects of habitat, diet, and sex were adjusted for, increasing hel-minth infection burdens negatively affected vaccine-specific antibody production. Using counterfactual modelling, we show that targeting anthelmintic treatment at heavily infected individuals would have improved their vaccine responsiveness by 2 to 4-fold. Our results indicate that the wild environment and access to a high-quality diet play a dramatic role in shaping the immune systems response to immunisation. Further, we show that laboratory settings, even when using a genetic diverse, non-traditional model, may systematically overestimate vaccine performance by failing to capture natural environmental variability. Our study provides a robust, causally explicit modelling approach to disentangle and quantify the complex factors that drive vaccine responsiveness in focal populations. This framework offers a path-way for predicting vaccine performance across diverse populations and identifying targeted interventions to enhance immunisation outcomes in real-world settings.

systems biology↗

bioRxiv2025

CD8 T cells mediate immunosurveillance for neoantigen+ epithelial stem cells in the colon

Epithelial cells in the colon accumulate substantial numbers of somatic mutations, some of which can be recognised as neoantigens. The ability of CD8 T cells to survey for neoantigen+ cells in the healthy colon would provide an early detection mechanism to prevent cancer, but it is unclear whether neoantigen-specific CD8 T cells can mediate this process of immunosurveillance without becoming tolerant. To address this question, we used a genetically engineered mouse model to express a neoantigen in the epithelial cells of the adult proximal colon. Induction of neoantigen expression led to rapid elimination of neoantigen+ epithelial cells from the colon in a CD8 T cell-dependent manner. Neoantigen-specific CD8 T cells acquired cytolytic function within the colon tissue under steady-state conditions, which was required for elimination of the neoantigen+ epithelial cells. Despite the elimination of [~]25% of their epithelial cells over a two-day period, the colons looked histologically normal. Immunofluorescence and single-cell transcriptomic analyses revealed that neoantigen-specific CD8+ T cells specifically target neoantigen+ stem cells at the crypt base, which was associated with Ki67 in the crypt wall and abundance of neoantigen-negative stem cells. Infiltrating neoantigen-specific CD8 T cells made IFNg and expressed PD-1, raising the question of why PD-1-dependent suppression did not prevent the acquisition of effector functions by these neoantigen-specific CD8 T cells. Despite an increased signature of interferon-stimulated genes in colonic epithelial cells, PD-L1 expression was surprisingly absent. Moreover, we found that colonic epithelial stem cells also did not express PD-L1 under conditions of chronic inflammation, such as ulcerative colitis, immune checkpoint-induced colitis, and ageing, or when directly stimulated with IFN-{gamma} in vitro. Analyses of the PD-L1 gene promoter across humans and mice showed hypermethylation at sites associated with PD-L1 repression in cancer. Thus, our data support a model in which the acquisition of neoantigens by colonic epithelial cells triggers CD8 T cell-mediated immunosurveillance. This results in the elimination of PD-L1-negative neoantigen+ stem cells by effector CD8 T cells and simultaneous repair of the colon by neoantigen-negative epithelial cells to prevent immunopathology.

immunology↗

bioRxiv2025

SCREAM: Single-cell Clustering using Representation Autoencoder of Multiomics

MotivationSingle-cell multiomics technologies offer unprecedented opportunities to study cellular heterogeneity. But, integrating information across different omics modalities remains a major challenge due to high dimensionality, sparsity, and modality-specific noise characteristics. To address this, we develop SCREAM (Single-cell Clustering using Representation Autoencoder of Multiomics), a novel deep learning framework for the robust integration and clustering of multi-modal single-cell data. SCREAM leverages Stacked Autoencoders (SAEs) to generate robust latent representations for each omics modality as well as for their fusion. Subsequently, borrowing Deep Embedding Clustering (DEC), SCREAM iteratively fine tunes the integrated mulitomics latent space and single-cell cluster assignments. ResultsWe evaluated SCREAM against eleven state-of-the-art methods using SNARE-seq and CITE-seq datasets. In this benchmarking, SCREAM consistently demonstrated superior performance, yielding the highest or near-highest Adjusted Rand Index (ARI) and Normalized Mutual Information (NMI) scores on both datasets. These findings validate SCREAM as a highly accurate and robust approach for identifying cell types from multiomics data. Furthermore, its multiomics embeddings provides biologically meaningful latent representations for diverse downstream analyses. AvailabilitySCREAM is available at http://www.github.com/cabsel/scream. Contactrgunawan@buffalo.edu

bioinformatics↗

bioRxiv2025

Neurodegeneration emerges at a cellular tipping point between protein accumulation and removal.

Protein aggregates are a pathological hallmark across neurodegenerative diseases. Yet, the disconnect between molecular-level aggregation and the emergence of disease severely limits mechanistic understanding of neurodegeneration. Here, we bridge this disconnect by showing that a cellular tipping point emerges as a universal feature across diseases from the competition between aggregate accumulation and removal. We map the resulting cellular phase transition with our high-throughput live-cell assay, measuring the tipping point that separates healthy cells from those with large aggregate loads. Using super-resolution imaging of brain tissue from Alzheimers and Parkinsons disease, we quantify how the balance of accumulation and removal is shifted in disease. We validate our framework by predicting how designed aggregation inhibitors shift the tipping point to restore cellular homeostasis. Our results provide a mechanistic framework connecting molecular-level aggregation to disease, paving the way for a quantitative, unified understanding of neurodegeneration and enabling predictions of therapeutic efficacy.

neuroscience↗

bioRxiv2025

GlycoEnzDB: A database of enzymes involved in human glycosylation

The glycan distribution on cells is governed by the stochastic activity of different families of enzymes that are together called glycoEnzymes. These include ~400 gene products or 2% of the proteome, that have recently been curated in an ontology called GlycoEnzOnto. With the goal of making this ontology more accessible to the larger biomedical and biotechnology community, we organized a web resource called GlycoEnzDB, presenting this enzyme classification both in terms of enzyme function and the pathways that they participate in. This information is linked to i) Figures from the "Essentials of Glycobiology" textbook, ii) General gene, enzyme and pathway data appearing in external databases, iii) Manual and generative-artificial intelligence (AI) based text describing the function and pathways regulated by these entities, iv) Single-cell expression data across cell lines, normal human cell-types and tissue, and v) CRISPR-knockout/activation/inactivation and Transcription factor activity predictions. Whereas these data are curated for human glycoEnzymes, the knowledge framework may be extended to other species also. The user-friendly web interface is accessible at www.virtualglycome.org/glycoenzdb.

biochemistry↗

bioRxiv2025

A novel mechanism for bacterial sporulation based on programmed peptidoglycan degradation

Many bacteria form spores to endure unfavorable conditions. While Firmicutes generate endospores through cell division, sporulation in non-Firmicutes remains less understood. The Gram-negative bacterium Myxococcus xanthus undergoes sporulation through two distinct mechanisms: rapid sporulation triggered by chemical induction and slow sporulation driven by starvation, both occurring independently of cell division. Instead, these processes depend on the complete degradation of the peptidoglycan (PG) cell wall by two lytic transglycosylases (LTGs), LtgA and LtgB. Remarkably, LtgB programs the pace of PG degradation by LtgA during rapid sporulation, ensuring a controlled process that prevents abrupt PG breakdown and the formation of non-resistant pseudospores. In addition to regulation between LTGs, PG degradation is also influenced by its synthesis; cells exhibiting increased muropeptide production often circumvent sporulation. These findings not only reveal novel mechanisms of bacterial sporulation but also shed light on the regulatory network governing PG dynamics.

microbiology↗

bioRxiv2025

Cell Type-Agnostic Transcriptomic Signatures Enable Uniform Comparisons of Neurodevelopment

Single-cell transcriptomics has revolutionized our understanding of neurodevelopmental cell identities, yet, predicting a cell types developmental state from its transcriptome remains a challenge. We perform a meta-analysis of developing human brain datasets comprising over 2.8 million cells, identifying both tissue-level and cell-autonomous predictors of developmental age. While tissue composition predicts age within individual studies, it fails to generalize, whereas specific cell type proportions reliably track developmental time across datasets. Training regularized regression models to infer cell-autonomous maturation, we find that a cell type-agnostic model achieves the highest accuracy (error = 2.6 weeks), robustly capturing developmental dynamics across diverse cell types and datasets. This model generalizes to human neural organoids, accurately predicting normal developmental trajectories (R = 0.91) and disease-induced shifts in vitro. Furthermore, it extends to the developing mouse brain, revealing an accelerated developmental tempo relative to humans. Our work provides a unified framework for comparing neurodevelopment across contexts, model systems, and species.

neuroscience↗

bioRxiv2024

Context matters: Integrative NMDA receptor dysfunction reveals effective seizure treatment in mice with a human patient GluN1 variant

Mutations in N-Methyl D-Aspartate receptors (NMDARs) cause epilepsy and profound cognitive impairment, though the underlying subunit-specific vulnerabilities remain unclear. We investigate the impact of a severe human variant in the lurcher motif of obligate GluN1 NMDAR subunit using transgenic mice, leveraging context-specific dysfunction to devise a surprising treatment. We show that the GluN1 Y647S variant significantly reduces current flow through isolated NMDARs in the mouse brain. However, this loss-of-function paradoxically extends NMDAR-dependent dendritic integration, causing prolonged circuit-wide excitation that promotes seizures. Mutant receptors fail to sufficiently engage opposing dendritic ion channels that normally prevent NMDAR overactivation. Boosting negative feedback restores normal dendritic integration and successfully treats seizures in vivo, despite loss-of-function of isolated NMDARs. We demonstrate how seizures arise from loss-of-function NMDARs and target the interaction between a GluN1 variants receptor-level effects and its dendritic environment to treat them effectively.

neuroscience↗

bioRxiv2024

SARS-CoV-2 Survival on Skin and its Transfer from Contaminated Surfaces

Understanding the transmission dynamics of SARS-CoV-2, particularly its transfer from contaminated surfaces (fomites) to human skin, is crucial for mitigating the spread of COVID-19. While extensive research has examined the persistence of SARS-CoV-2 on various surfaces, there is limited understanding of how efficiently it transfers to human skin, and how long it survives on the skin. This study investigates two key aspects of SARS-CoV-2 transmission: (1) the transfer efficiency of SARS-CoV-2 from non-porous (plastic and metal) and porous (cardboard) surfaces to a 3D human skin model (LabSkin), and (2) the survival of SARS-CoV-2 on the skin under different temperature conditions. First, we validated LabSkin as a suitable surrogate for human skin by comparing the transfer efficiency of the bacteriophage Phi 6 from surfaces to LabSkin and to human volunteers fingers. No significant differences were observed, confirming LabSkins suitability for these studies. Subsequently, the transfer of SARS-CoV-2 from surfaces to LabSkin was assessed, showing that plastic and metal surfaces had similar transfer efficiencies ([~]13%), while no transfer occurred from cardboard once the inoculum had dried on the surface. Finally, the survival of SARS-CoV-2 on skin was assessed, showing a rapid decay at higher temperatures, with a half-life ranging from 2.8 to 17.8 hours depending on the temperature. These findings enhance our understanding of viral transmission via fomites and inform public health strategies to reduce the risk of SARS-CoV-2 transmission through surface contact.

microbiology↗

bioRxiv2024

Functional and evolutionary constraints of wtf killer meiotic drivers

Killer meiotic drivers are selfish DNA loci that sabotage the gametes that do not inherit them from a driver+/driver- heterozygote. These drivers often employ toxic proteins that target essential cellular functions to cause the destruction of driver- gametes. Identifying the mechanisms of drivers can expand our understanding of infertility and reveal novel insights about the cellular functions targeted by drivers. In this work, we explore the molecular mechanisms underlying the wtf family of killer meiotic drivers found in fission yeasts. Each wtf killer acts using a toxic Wtfpoison protein that can be neutralized by a corresponding Wtfantidote protein. The wtf genes are rapidly evolving and extremely diverse. Here we found that self-assembly of Wtfpoison proteins is broadly conserved and associated with toxicity across the gene family, despite minimal amino acid conservation. In addition, we found the toxicity of Wtfpoison assemblies can be modulated by protein tags designed to increase or decrease the extent of the Wtfpoison assembly, implicating assembly size in toxicity. We also identified a conserved, critical role for the specific co-assembly of the Wtfpoison and Wtfantidote proteins in promoting effective neutralization of Wtfpoison toxicity. Finally, we engineered wtf alleles that encode toxic Wtfpoison proteins that are not effectively neutralized by their corresponding Wtfantidote proteins. The possibility of such self-destructive alleles reveals functional constraints on wtf evolution and suggests similar alleles could be cryptic contributors to infertility in fission yeast populations. As rapidly evolving killer meiotic drivers are widespread in eukaryotes, analogous self-killing drive alleles could contribute to sporadic infertility in many lineages. Author SummaryDiploid organisms, such as humans, have two copies of most genes. Only one copy, however, is transmitted through gametes (e.g., sperm and egg) to any given offspring. Alternate copies of the same gene are expected to be equally represented in the gametes, resulting in random transmission to the next generation. However, some genes can "cheat" to be transmitted to more than half of the gametes, often at a cost to the host organism. Killer meiotic drivers are one such class of cheater genes that act by eliminating gametes lacking the driver. In this work, we studied the wtf family of killer meiotic drivers found in fission yeasts. Each wtf driver encodes a poison and an antidote protein to specifically kill gametes that do not inherit the driver. Through analyzing a large suite of diverse natural and engineered mutant wtf genes, we identified multiple properties--such as poison self-assembly and poison-antidote co-assembly--that can constrain poison toxicity and antidote rescue. These constraints could influence the evolution of wtf genes. Additionally, we discovered several incompatible wtf poison-antidote pairs, demonstrating expanded potential for self-killing wtf alleles. Such alleles could potentially arise spontaneously in populations cause infertility.

genetics↗

bioRxiv2024

Grin1Y647S/+ Mice: A Preclinical Model of GRIN1-Related Neurodevelopmental Disorder

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 is carried by a 34-year-old female with seizures and intellectual disability. This study builds upon initial in vitro investigations of the functional impacts of this variant in the SYTANLAAF domain of the GluN1 M3 helix and examines its in vivo consequences in a mouse model. 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. Grin1Y647S/+ mice were created by CRISPR-Cas9 endonuclease-mediated transgenesis and the molecular, electrophysiological, and behavioural consequences of the variant were examined. Additionally, de-identified patient data were collected to examine the representative nature of Grin1Y647S/+ mice in modelling specific aspects of patient symptomology. In vitro, NMDARs containing GluN1-Y647S showed altered sensitivity to endogenous agonists and negative allosteric modulators, and reduced cell surface trafficking. Ex vivo, Grin1Y647S/+ mice displayed a reduction in whole brain GluN1 levels and a deficiency in NMDAR-mediated synaptic transmission in the hippocampus. Behaviourally, Grin1Y647S/+ mice exhibited altered vocalizations, muscle strength, sociability, and problem-solving, as well as spontaneous convulsions that were ameliorated with supplementation of {beta}-hydroxybutyrate (BHB), an endogenously produced ketone body. The Y647S variant confers a complex in vivo phenotype, which reflects largely diminished properties of NMDAR function. As a result, Grin1Y647S/+ mice display atypical behaviour in domains relevant to the clinical characteristics of GRIN1-NDD and the individual carrying the variant, which allowed for the identification of BHB supplementation as a potential anti-convulsant treatment. Ultimately, the characterization of Grin1Y647S/+ mice accomplished in the present work, expands our understanding of the mechanisms underlying GRIN1-NDD and provides a foundation for the continued development of novel therapeutics.

neuroscience↗