Biology subjects

Zhang, Z.

Publications and source records attributed to Zhang, Z..

At least 379 records · Page 21Linked to original sources

bioRxiv2025

Universal principles of protein resource allocation among cellular organelles revealed by yeast large-scale absolute quantitative proteomics

The presence of organelles is a hallmark distinguishing eukarya from bacteria and archaea, and this culminates in compartmentalization of cellular metabolism and subsequent metabolic specialization. Here we established a dataset encompassing over 300 absolute quantitative proteomes, the largest to date, across two yeast species under diverse experimental conditions. Leveraging big data analysis, formula fitting, and machine learning models, quantitative correlations among protein abundance, organelle-level resource distribution, and cellular phenotypes were elucidated at a system level. We found that protein resources always exhibit robust and precise distribution at the organelle level across distinct conditions. Specifically, at high specific growth rates, the protein mass fraction from some main organelles, i.e., peroxisome and nucleus, is consistently reduced to offset the increasing protein resource demand from the ribosome. Meanwhile, we found that the nutrition limitation could induce resource recycling by upregulating protein resources within the vacuole and lipid droplets to sustain stress adaptation. Importantly, our integrative analysis demonstrates that protein mass fraction from less than 4 organelles (e.g., nucleus and ribosomes) can accurately predict diverse yeast physiological parameters (e.g., specific growth rate, oxygen uptake rate), and a core set of 37 proteins could predict resource allocation among 24 main organelles and sub-organelles with high accuracy (average R^2 > 0.9). Finally, we found organelle resource allocation reflects the divergence of yeast species. For example, anaerobic conditions and respiratory suppression have less influence on Crabtree-positive yeast, i.e., Saccharomyces cerevisiae, with respect to organelle resource allocation but have a larger effect on the Crabtree-negative yeast Issatchenkia orientalis, thus suggesting that cellular resources have facilitated adaptive evolution. In summary, the high-quality, genome-scale quantitative proteomic dataset for yeast species offers an unprecedented opportunity for understanding the basic principles underlying resource allocation at the organelle level, laying theoretical foundations for precision engineering of cell factories in synthetic biology. The resource used in this study is available at https://yeast-proteome-database.streamlit.app/.

systems biology↗

bioRxiv2025

Query Augmented Generation (QAG) from the Genomic DataCommons for Accurate Variant Statistics

In precision oncology, researchers often use public knowledgebases to check somatic variant frequencies against their cohort data. Large language models (LLMs) can quickly answer questions on somatic variant frequencies, but often hallucinate and give inaccurate results for factual data. Using synthetic queries, we show that somatic variant frequencies in baseline LLM responses are underestimated compared to the Genomic Data Commons (GDC), the worlds largest data commons for cancer research. We present a modular architecture called Query Augmented Generation (QAG) for integrating LLMs with high-quality data from a third party data source such as a data commons, knowledgebase or database. We apply QAG to the GDC to help researchers obtain accurate frequencies for somatic variants, copy number variants, and MSI status--even for complex queries requiring multiple steps in the GDC portal and API. Our software is deployed as a model context protocol (MCP) server on Hugging Face and available on GitHub.

bioinformatics↗

bioRxiv2025

Hypoimmunogenic human motor neurons induced from iPSCs in vivo substantially ameliorate ALS disease in large animal models

Stem cell-based therapy holds great potential for substituting degenerated motor neurons (MNs) in amyotrophic lateral sclerosis (ALS). Missing protocols for advanced differentiation of transplanted cells into MNs, immune rejection, and the lack of suitable ALS models for preclinical trials have slowed the development of effective therapies. Here, we employed multiplex genetic-editing to generate a novel human pluripotent stem cell line containing doxycycline (Dox)-inducible MNs-specific transcription factors and comprehensively modified immunomodulatory genes. We transplanted these cells into the spinal cord of ALS large animal models (SOD1G93A pigs and TIA1P362L rabbits), which faithfully recapitulate pathologies and symptoms observed in ALS patients. The transplanted cells could efficiently differentiate into functional MNs upon Dox treatment in vivo, distribute throughout the spinal cord and motor cortex via extensive migration, survive long-term without the need for immunosuppression. Notably, these MNs integrated into host neural circuits, as evidenced by their long projection of peripheral axons to target muscle and reformation of neuromuscular junctions. As result, pathologies and motor deficits were substantially ameliorated in both animal models. One Sentence SummaryHypoimmunogenic human motor neurons induced from iPSCs in vivo reform neuromuscular junctions and ameliorate ALS disease in pig and rabbit models.

neuroscience↗

bioRxiv2025

Instruction-tuned extraction of virus-host interactions from integrated scientific evidence

MotivationViral infectious diseases continue to pose a major threat to global health. Understanding protein-protein interactions (PPIs) and RNA-protein interactions (RPIs) between viruses and hosts is essential for elucidating infection mechanisms. However, manual curation of these interactions from biomedical literature is inefficient, creating a pressing need for automated and scalable extraction methods. Large language models (LLMs), such as the generative pre-trained transformer (GPT) and bidirectional encoder representations from transformers (BERT), offer promising solutions. Yet, most existing datasets focus on abstracts, overlooking other information-rich sections. We aim to develop a data-efficient approach to extract virus-host interaction (VHI) entities from full-text biomedical articles, including Results, Methods and tables. To our knowledge, this is the first study to apply instruction tuning to full-text VHI extraction ResultsWe curated a dataset containing 3, 395 PPI and 674 RPI entities from the Results, Materials and Methods sections, along with 566 PPIs and 793 RPIs from tables. Under low-resource conditions (<500 training examples), our instruction-tuned ChatMed-VHI model achieves the best overall performance (F1: 89.7%, Precision: 95.3%), outperforming PubMedBERT (F1: 74.6%, Precision: 75.1%). When scaled to the full dataset (>4, 000 training examples), ChatMed-VHI maintained the highest overall performance, while PubMedBERT achieved slightly higher precision (92.3% vs. 91.3%). Notably, ChatMed-VHI improved F1 and recall by 2.79% but precision dropped by 4.20% with more training data, whereas PubMedBERT improved consistently across all metrics. These results demonstrate the effectiveness of instruction-tuned LLMs for full-text biomedical extraction tasks, and position ChatMed-VHI as a scalable, domain-adaptable solution for VHI mining.

bioinformatics↗

bioRxiv2025

Spontaneous peripheral oxygen desaturation and apnea events in mice vary by strain and inspired oxygen level

Mouse models of chronic intermittent hypoxia are widely used in research to understand the role of sleep apnea in disease pathogenesis. Mice exposed to periodic reductions in FIO2 model arterial desaturations observed in humans and recapitulate many comorbidities of sleep apnea. Here, we perform a detailed characterization and confirm reports that mice in room air experience spontaneous, periodic desaturation events. We measured peripheral oxygen saturation in the four mouse strains most commonly used in intermittent hypoxia research (C57BL/6J, CD1, BALB/c, and 129S1) and subjected them to conscious barometric plethysmography to measure oxygen desaturations and apneas simultaneously and took measurements across a range of fractional inspired oxygen (FIO2). As expected, all strains experienced periodic apneas that were followed by desaturations and decreasing FIO2 resulted in a reduction of spontaneous apneic events (p = 0.001). Surprisingly, most oxygen desaturations were not preceded by apneas or hypopneas, and mice experienced more desaturations at lower FIO2 (p < 0.001), despite less frequent apneas. Furthermore, we found strain differences in ventilatory response consistent with prior findings and a novel strain difference in 129S1 mice. These data suggest that spontaneous desaturations are caused not only by apneas and hypopneas but also by other mechanisms, independent of respiration. Our findings provide important context for mouse models of sleep apnea and associated diseases, and future work should explore the extent to which these findings are relevant in humans.

physiology↗

bioRxiv2025

Detection and monitoring of translocation renal cell carcinoma via plasma cell-free epigenomic profiling

TFE3 translocation renal cell carcinoma (tRCC), an aggressive kidney cancer driven by TFE3 gene fusions, is frequently misdiagnosed owing to morphologic overlap with other kidney cancer subtypes. Conventional liquid biopsy assays that detect tumor DNA via somatic mutations or copy number alterations are unsuitable for tRCC, since it often lacks recurrent genetic alterations and because fusion breakpoints are highly variable between patients. We reasoned that epigenomic profiling could more effectively detect tRCC, because the driver fusion constitutes an oncogenic transcription factor that alters gene regulation. By defining a TFE3-driven epigenomic signature in tRCC cell lines and detecting it in patient plasma using chromatin immunoprecipitation and sequencing, we distinguished tRCC from clear cell RCC (AUC=0.87) and healthy controls (AUC=0.91) at low tumor fractions (<1%). This work establishes a framework for non-invasive epigenomic detection, diagnosis and monitoring of tRCC, with implications for other mutationally quiet, fusion-driven cancers. SIGNIFICANCETranslocation renal cell carcinoma (tRCC) is an aggressive fusion-driven subtype of kidney cancer that is frequently misdiagnosed due to morphologic overlap with other kidney cancer subtypes. Conventional liquid biopsy assays targeting DNA alterations are suboptimal for use in tRCC due to its paucity of genomic changes. We demonstrate the utility of cell-free chromatin profiling to noninvasively detect and monitor tRCC with high accuracy, a method that could have applicability to other genomically quiet cancers.

genomics↗

bioRxiv2025

T-cell signaling relies on partial CD45-exclusion at sub-micron sized cellular contacts

How cell contact initiates T-cell activation is uncertain. The local exclusion of the receptor-type protein tyrosine phosphatase CD45 at cell contacts is believed to trigger immune receptor signaling but this is yet to be observed for T cells interacting with authentic cellular targets. Here, quantitative imaging of T cells interacting with tumor cells presenting either native or clinically relevant bi-specific TCR ligands, revealed that they form multiple sub-micron sized close contacts with their targets. The contacts were stabilised by the adhesion protein CD2, but efficient ligand detection required both CD2 and integrin ligation. CD45 was excluded from close contacts at the time of ZAP70 recruitment and signaling, but only partially (30- 40%). A single-cell, mass cytometric analysis showed that this change in kinase/phosphatase activity provoked strong T-cell activation and potent cytotoxicity via very small changes in signaling fluxes. Spatial stochastic simulations suggested that the proximal T-cell signaling network is optimised for efficient antigen discrimination in the setting of partial CD45 exclusion. Our work re-frames early T-cell activation as a process initiated by relatively subtle changes in kinase/phosphatase activity acting on small numbers of signaling effectors at minute cellular contacts.

immunology↗

bioRxiv2025

Post-inhibitory rebound firing drives hypothalamic activation for male mating

Many behaviorally relevant limbic circuits are dominated by inhibitory connections, raising the question of how neuronal activation arises in such contexts. In male mating, both activation of mPOA and its inhibitory inputs are essential--a paradox previously ascribed to disinhibition. Here, we show that the mPOA largely lacks local inhibitory circuits, arguing against disinhibition. Instead, in vivo recordings reveal that mount-active mPOA neurons are suppressed prior to behavioral onset, and this inhibition negatively correlates with subsequent activation, consistent with post- inhibitory rebound firing (PIR). A biologically plausible conductance-based model demonstrates that synaptic inhibition interacts with T-type Ca{superscript 2} currents -- the ionic basis of PIR -- to promote mPOA neuron firing. Experimentally, bidirectional manipulations of mPOA T-type Ca{superscript 2} channels confirm this mechanism: knockdown reduces PIR and impairs male mating, while overexpression enhances mating. Together, these results identify PIR as a critical mechanism by which inhibition promotes activation in limbic circuits to drive male mating.

neuroscience↗

bioRxiv2025

Dyslipidemic SPTLC3 Integrates Bile Acid-FXR Signaling with Sphingolipid Remodeling in MASLD

Molecular mechanisms driving metabolic disease pathogenesis remain poorly understood. Genetic and functional studies implicate SPTLC3 with dyslipidemia. SPTLC3 synthesizes atypical long-chain bases (LCB) precursors for sphingolipid production. We demonstrate significant SPTLC3 expression in human liver. ORMDL1-3 regulate SPTLC3 post-translationally in hepatic and non-hepatic cells. Independently, farnesoid X receptor (FXR) represses hepatic SPTLC3 transcription via a negative promoter element. In mice, high-fat diet (HFD) induced whereas bile acids normalized hepatic SPTLC3 transcription. SPTLC3 derived LCBs in plasma originate from the liver and are elevated in HFD-fed mice and in patients with metabolic dysfunction-associated steatotic liver disease (MASLD). Cross-species comparison revealed marked differences in LCB composition between mice and humans. Notably, omega-3-methylsphingosine (meC18SO) was significantly associated with MASLD in humans but undetectable in mice. In Huh7 cells, meC18SO enhanced complex II and IV activity, oxygen consumption, and mitochondrial ROS content. FXR-SPTLC3 axis and presented findings have potential implications for future translational research.

biochemistry↗

bioRxiv2025

Transcriptional Readthrough at Atf4 Locus Suppresses Rps19bp1 and Impairs Heart Development

BACKGROUNDActivating Transcription Factor 4 (ATF4) functions as a transcriptional regulator in various cell types and tissues under both physiological and pathological conditions. While previous studies have linked ATF4 activation with promoting cardiomyocyte (CM) death in dilated cardiomyopathy (DCM), atrial fibrillation, and heart failure, its role in developing CMs remains unexplored. METHODSWe generated multiple distinct CM-specific (Atf4cKO(e2/3/pA) and Atf4cKO(e2)) and global Atf4 knockout (Atf47del/7del and Atf41ins/1ins) mouse models targeting different Atf4 regions, as well as cardiomyocyte-specific deletion of Rps19bp1 to study cardiac phenotypes. Detailed morphological and molecular analyses were performed. RESULTSAtf4cKO(e2/3/pA) (targeting exon 2-3 including the polyadenylation signal (polyA)) mice exhibited severe cardiac defects and died before E17.5, likely due to ectopic activation of p53 signaling pathway resulting from Rps19bp1 downregulation, a potent suppressor of p53. Further investigation revealed that deleting the polyA signal of Atf4 in Atf4cKO(e2/3/pA) mice led to transcriptional readthrough, resulting in the formation of an Atf4-Cacna1i fusion transcript and Rps19bp1 downregulation. To avoid readthrough while abolishing ATF4 function, we introduced small indels into exon 3 of Atf4 in mice (Atf47del/7del and Atf41ins/1ins), which showed normal Rps19bp1 expression and cardiac morphology. Importantly, CM-specific deletion of Rps19bp1 recapitulated the cardiac defects and transcriptional change seen in Atf4cKO(e2/3/pA) mice. CONCLUSIONSWe found that the downregulation of Rps19bp1, not loss of ATF4 function, underlying the cardiac phenotypes in Atf4cKO(e2/3/pA) mice. The reduced expression of Rps19bp1 in Atf4cKO(e2/3/pA) mice is likely due to the unintentional deletion of Atf4 polyA signal and subsequent transcriptional readthrough, underscoring the essential role of RPS19BP1, not ATF4, in cardiac development. Consistent Rps19bp1 downregulation has been observed in other tissue-specific Atf4 knockout models utilizing the Atf4fl(e2/3/pA) allele, suggesting that previously reported Atf4 KO phenotypes may result from Atf4 transcriptional readthrough effects. These findings reveal a locus-dependent transcriptional interference mechanism and emphasize the importance of avoiding confounding cis effects in genetically engineered models. TRANSLATIONAL PERSPECTIVEOur findings clarify ATF4s role in heart development by showing that cardiac defects in cardiomyocyte-specific ATF4 knockout mice--using a widely employed floxed ATF4 line--result from unintended downregulation of RPS19BP1 caused by transcriptional readthrough. This shifts the focus from ATF4 to RPS19BP1, a key regulator of p53 activity, as a potential driver of cardiac developmental abnormalities. Clinically, these insights caution against misinterpretation of genetic knockout models and highlight RPS19BP1 as a promising target for congenital heart disease and related cardiac dysfunctions, with potential implications for future therapies.

genetics↗

bioRxiv2025

HP1β and densely packed chromatin form separate microdomains in mouse ES cells, which are reconfigured upon exit from naive pluripotency

Heterochromatin proteins play a key role in establishing local chromatin structure to control the transcription of target genes. Here we uncover a surprising segregation between regions of high DNA- and high heterochromatin protein 1{beta} (HP1{beta})-density in mouse ES cells. DNA-low/HP1{beta}-high foci retain freely diffusing HP1{beta}, and form via condensation through a multitude of weak interactions on top of HP1{beta} that is bound stably to chromatin. DNA-high/HP1{beta}-low foci exclude freely diffusing HP1{beta} and display reduced chromatin mobility, suggesting a higher degree of chromatin self-interaction and a more repressive environment. Finally, the two types of environments are intertwined in DNA-high/HP1{beta}-high foci, where HP1{beta} maintains heterochromatin in a more compact yet dynamic chromatin state. During the exit from naive pluripotency HP1{beta} is lost from regions of high DNA density as cells transition through the formative state, which might facilitate the reconfiguration of genome structure accompanying a change in cell state that we observed previously. Subsequently, as cells enter primed pluripotency, canonical heterochromatin is established.

molecular biology↗

bioRxiv2025

GASPS: A Multi-Omics Framework for Defining Genomic Aberration-Driven Signatures and Predicting Patient Outcomes in Lung Cancer

Lung cancer is the most common cause of cancer-related death worldwide. Recent advancements in targeted therapies and immunotherapies have achieved remarkable success. However, patient responses to treatments with lung cancer vary substantially. The mutation status of driver genes can direct personalized treatment, but their prognostic value and treatment efficacy are limited. In this study, we developed a statistical framework named Genomic Aberration-Derived Signature for Patient Stratification (GASPS) to characterize the transcriptomic deregulation of driver genomic aberrations and stratify patients. By applying GASPS to The Cancer Genome Atlas Lung Adenocarcinoma (TCGA-LUAD) data, we developed gene signatures for 38 driver genomic aberrations, including gene mutations, amplifications, and deletions. These signatures were applied to independent lung cancer transcriptomic datasets containing a total of 2,226 patient samples. Our results indicated that these driver gene signatures are much more prognostic than their corresponding genomic mutations. Interestingly, the two EGFR-related signatures characterizing EGFR mutation and amplification, respectively, exhibited contrasting associations with prognosis, treatment response, and immune infiltration in the tumor microenvironment. Moreover, the STK11 mutation signature, rather than the mutation status, was found to be predictive of the response and long-term benefit of patients treated with immune checkpoint blockade therapy in lung cancer. This framework is readily applicable to most cancer types using existing data to improve prognostic risk assessment and treatment efficacy by guiding personalized therapies.

bioinformatics↗

bioRxiv2025

Ongoing thoughts at rest reflect functional brain organization and behavior

Resting-state functional connectivity (rsFC)--brain connectivity observed when people rest with no external tasks--predicts individual differences in behavior. Yet, rest is not idle; it involves streams of thoughts. Are these ongoing thoughts reflected in FC and do they contribute to the relationship between rsFC and behavior? To test this question, we developed an annotated rest paradigm where participants rated and verbally described their thoughts after each rest period during functional MRI (N = 60). Our findings revealed rich and idiosyncratic thoughts across individuals. Similarity in thoughts was associated with more similar FC patterns within and across individuals. In addition, both thought ratings and topics could be decoded from FC. Furthermore, neuromarkers of these thoughts generalized to unseen individuals in the Human Connectome Project dataset (N = 908), where decoded thought patterns during rest predicted positive vs. negative trait-level individual differences. Together, our findings reveal that ongoing thoughts at rest are reflected in brain dynamics and these network patterns predict everyday cognition and experiences. Understanding subjective in-scanner experiences is thus crucial in characterizing the relationship between individual differences in functional brain organization and behavior.

neuroscience↗

bioRxiv2025

Epilepsy-Associated SCN2A-L1342P Mutation Drives Network Hyperexcitability and Widespread Transcriptomic Changes in Human Cortical Organoids

ObjectiveSCN2A pathogenic mutations, such as the recurrent heterozygous Nav1.2-L1342P, are monogenic causes of epilepsy. In this human-induced pluripotent stem cell model system, we aim to investigate the molecular and cellular mechanisms underlying the SCN2A-L1342P-associated pathology. MethodsUsing a human male iPSC reference line (KOLF) carrying the Nav1.2-L1342P mutation, we generated 3D cortical organoids for functional studies. Patch clamp and multi-electrode array (MEA) recordings, immunocytochemistry, and RNA sequencing were used to characterize the disease phenotypes. ResultsNav1.2-L1342P organoid neurons displayed increased intrinsic excitability, and amplified excitatory post-synaptic currents, which are consistent with an increase in excitatory synapse formation revealed by PSD95/SYN1 immunostaining. Moreover, elevated network firing activity, as demonstrated by MEA, indicates a pronounced network hyperexcitability. Transcriptomic profiling of organoids carrying the Nav1.2-L1342P mutation further revealed significant alterations in synaptic, glutamatergic, and developmental pathways. SignificanceOur findings demonstrate that the Nav1.2-L1342P mutation drives a multifaceted disease phenotype, including network hyperexcitability and disruption of pathways related to neuronal and synaptic functions. These results advance our understanding of SCN2A-related Developmental and Epileptic Encephalopathy (DEE), laying a foundation for personalized interventions. Key PointsO_LIKey Point 1: Human neurons carrying epilepsy-causing SCN2A-L1342P display intrinsic hyperexcitability in cortical organoids. C_LIO_LIKey Point 2: Synaptic transmission is enhanced in organoids carrying the SCN2A-L1324P mutation, consistent with the presence of elevated excitatory synapses, which leads to increased network hyperexcitability. C_LIO_LIKey Point 3: Transcriptomics analysis reveals that the SCN2A-L1342P mutation causes significant differential changes in forebrain developmental genes, synaptic and glutamatergic signaling pathways, and enhances cellular senescence and apoptosis. C_LI

neuroscience↗

bioRxiv2025

NSF is required for diverse endocytic modes by promoting fusion and fission pore closure in secretory cells

The ATPase N-ethylmaleimide-sensitive factor (NSF), known for disassembling SNARE complexes, plays key roles in neurotransmitter release, neurotransmitter (AMPA, GABA, dopamine) receptor trafficking, and synaptic plasticity, and its dysfunction or mutation is linked to neurological disorders. These roles are largely attributed to SNARE-mediated exocytosis. Here, we reveal a previously unrecognized role for NSF: mediating diverse modes of endocytosis--including slow, fast, ultrafast, overshoot, and bulk--by driving closure of both fusion and fission pores. This function was consistently observed across large calyx nerve terminals, small hippocampal boutons, and chromaffin cells using capacitance recordings, synaptopHluorin imaging, electron microscopy, and multi-color pore-closure imaging. Results were robust across four NSF inhibitors, gene knockout, knockdown, and specific mutations. These findings establish NSF as a central regulator of membrane fission, kiss-and-run fusion, endocytosis, and exo-endocytosis coupling--offering new mechanistic insights into its diverse physiological and pathological roles in synaptic transmission, receptor trafficking, and neurological diseases.

neuroscience↗

bioRxiv2025

Embodied Intelligence Unlocks Autonomous Microscopy

Advanced microscopy is a cornerstone of modern science, yet its potential is constrained by a reliance on manual operation, which struggles with the complexity and reproducibility of long-term experiments protocols. While scripting offers a degree of automation, it lacks the generalizability to adapt to new samples or dynamic biological events. A fundamental challenge is the absence of an intelligent system that can interpret high-level scientific intent and ground it in the physical actions of the microscope. To bridge this gap, we introduce an Embodied Intelligent Microscope System (EIMS) with hierarchical reasoning structure that reimagines the microscope autonomous control. This system leverages the advanced reasoning of large models to interpret complex user commands and decompose them into actionable steps. To solve the critical grounding problem, we constrain the models output to the feasible action space, effectively serving as the models "hands and eyes" in the physical world. We demonstrate that our system achieves zero-shot generalization on complex, multi-step protocols and successfully automates challenging biological missions requiring expert-level judgment, such as capturing the sparse spatiotemporal events of cell mitosis and locating scatteredly distributed organoids. This work establishes a new paradigm for scientific instrumentation--fusing high-level intent understanding with grounded, dynamic execution--and provides a generalizable framework for deploying embodied intelligence to accelerate autonomous scientific discovery.

bioengineering↗

bioRxiv2025

Neuroanatomical Basis of Coma in Acute Ischemic Stroke

BackgroundAcute ischemic stroke (AIS) can lead to profound disturbances in consciousness, including coma, which is associated with poor prognosis and increased mortality. Clarifying the lesion patterns that precipitate loss of consciousness can refine pathophysiological models and guide prognosis. ObjectivesIn this study, we aim to identify the brain regions most commonly affected in comatose AIS and determine whether specific combinations of lesions are necessary and sufficient to produce coma. MethodsWe retrospectively analyzed 476 AIS patients (52 comatose) using diffusion-weighted imaging. Infarcts were automatically segmented, manually verified, and normalized to MNI space. Support vector regression lesion-symptom mapping (SVR-LSM) quantified voxel-wise associations with coma, controlling for lesion volume. To assess the necessity and sufficiency of lesion combinations, we employed permutation-based nested logistic regression models comparing all subsets of four anatomical predictors: brainstem, thalamus, cerebellum, and the rest of brain lesions. ResultsSVR-LSM revealed that coma was strongly associated with lesions involving the brainstem, thalamus, and cerebellum, whereas non-comatose patients exhibited predominantly cortical infarcts. Nested model comparisons showed that concurrent lesions to both the brainstem and thalamus were necessary and sufficient for coma. Additional involvement of the cerebellum or cerebral cortex did not improve predictive performance. ConclusionsComa after AIS results from a dual-node subcortical lesion pattern involving both the brainstem and thalamus. Cerebellar and cortical lesions, even when extensive, did not induce coma in the absence of the dual-brainstem and thalamic lesions. These observations emphasize the predominant role of lesion location over lesion volume in the pathogenesis of coma. They also support mechanistic models that position the brainstem and thalamic hubs as central to the neural circuitry underlying arousal. Furthermore, these findings delineate a specific anatomical substrate that may serve as a strategic target for circuit-based neuroprotective and neuromodulatory therapies.

neuroscience↗

bioRxiv2025

Chemoenzymatically Synthesized O-Acetylated GD3 Gangliosides to Examine Viral Receptor Specificities in a Cellular Context

Gangliosides are a class of sialic acid-containing glycosphingolipids involved in a wide range of biological processes. The terminal sialic acid of gangliosides can be O-acetylated at C7 and/or C9 hydroxyl, contributing to ganglioside structural complexity and function. It has been difficult to obtain panels of structurally well-defined O-acetylated gangliosides for binding and functional studies. We describe here a chemoenzymatic strategy that can provide, for the first time, 7-O-, 9-O-, and 7,9-di-O-acetylated GD3 gangliosides. It is based on the chemical assembly of a common tetrasaccharide precursor as -glycosyl fluoride that is coupled to sphingosine by a glycosynthase, followed by O-acetyl editing by coronaviral hemagglutinin-esterases. The resulting synthetic glycosphingolipids have been employed for cell surface remodeling of erythrocytes. Analysis by liquid chromatography and ion mobility mass spectrometry (LC-IM-MS) demonstrated successful integration of the glycosphingolipids into the plasma membrane with preservation of acetyl ester patterns. Using human coronavirus HKU1 spike-functionalized virus-like particles, we demonstrate that the resulting glycan-remodeled erythrocytes can be utilized in hemagglutination studies as a label free method to investigate viral protein binding to individual glycoforms in a cellular environment. Entry for the Table of Contents O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=112 SRC="FIGDIR/small/670503v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@37de01org.highwire.dtl.DTLVardef@1d043faorg.highwire.dtl.DTLVardef@1ee57borg.highwire.dtl.DTLVardef@6bf474_HPS_FORMAT_FIGEXP M_FIG Table of Contents 7-O-, 9-O-, and 7,9-di-O-acetylated GD3 gangliosides can be prepared by chemical assembly of a tetrasaccharide as -glycosyl fluoride that is coupled to sphingosine using a glycosynthase, followed by O-acetyl editing by coronaviral hemagglutinin-esterases. Cell surface remodeling of erythrocytes using the GD3 derivatives provide a tool to examine viral receptor specificities. C_FIG

biochemistry↗