Biology subjects

Ji, Y.

Publications and source records attributed to Ji, Y..

At least 37 records · Page 2Linked to original sources

bioRxiv2026

Sex stratified analyses enable new genetic insights into brain imaging phenotypes

Sex differences are commonly observed in neuroimaging phenotypes and in the risk of brain diseases, yet the underlying genetic mechanisms remain poorly understood. We investigated sex differences in the genetic architecture of 805 neuroimaging phenotypes in 22,950 males and 22,950 females matched for sample size and covariates, and systematically compared sex-stratified with sex-combined genetic analyses. We found eight variant-trait associations with significant sex differences, 235 fine-mapped sex-dominant causal associations, 457 sex-dominant colocalizations with sex hormones, and 96 sex-dominant colocalizations with schizophrenia. Compared with sex-combined analysis, sex-stratified analysis identified 47 new genetic associations, 170 new fine-mapped causal associations, 1,019 new colocalizations with sex hormones, and 191 new colocalizations with schizophrenia. Additionally, sex-stratified analysis improved global heritability and genetic-correlation estimates and enhanced polygenic prediction for certain phenotypes. This work highlights the need to routinely perform sex-stratified genetic association analyses to elucidate sex-specific and sex-shared genetic control of neuroimaging phenotypes and related disorders.

genetics↗

bioRxiv2026

Continental-scale multi-omics reveals a distinct microbial-viral biome in sandy beach ecosystems structured by tidal zonation

Sandy beaches are dynamic coastal interfaces shaped by strong physical forcing and intense exchange between marine and terrestrial environments, yet their microbiomes remain poorly resolved at the genomic scale. Here we present a genome-resolved survey of microbial and viral communities across sandy beaches spanning a continental-scale latitudinal gradient along the Chinese coastline. By integrating cross-shore sampling, coastal geochemistry and large-scale multi-omics, we generated 978 metagenomes, 63 viromes and 72 metatranscriptomes, reconstructing 13,337 metagenome-assembled genomes and 38,255 viral populations. Sandy beach microbiomes exhibit exceptionally high genomic novelty, with more than 90% of species-level genomes representing previously undescribed taxa, suggesting that permeable coastal sediments constitute a distinct microbial and viral reservoir. Tidal zonation emerged as a dominant ecological driver structuring microbial diversity, metabolic strategies and virus-host interactions across cross-shore gradients. Genome-resolved analyses revealed systematic metabolic shifts from oxic heterotrophy in supratidal sediments toward increasingly chemolithotrophic and autotrophic pathways toward the low-intertidal and subtidal zone. Sandy beach microbiomes further encode broad potential for hydrocarbon and plastic transformation, together with diverse biosynthetic and antibiotic resistance repertoires that may mediate microbial chemical interactions. Together, these findings identify sandy beaches as a previously under-recognized microbial-viral biome shaped by tidal forcing, providing insight into microbiome evolution and coastal ecosystem resilience under increasing anthropogenic pressure.

microbiology↗

bioRxiv2026

Ultra-large targeted DNA integrations in primary human cells

Genetic engineering experiments and therapies are constrained by the size of DNA integrations into human cells genomes. Existing AAV, lentiviral, and non-viral methods rapidly decrease in integration efficiency beyond [~]5kb of sequence. Through systematic evaluation of non-viral DNA template formats, we identified circular ssDNA and dsDNA as capable of mediating >5kb integrations. Large circular DNA delivery efficiency and its impacts on cell viability and payload expression could be significantly improved with small DNA "helper" plasmids, mRNA-encoded nucleases, and sequence design optimizations. Collectively, these modifications enabled ultra-large--up to 10 kb DNA--integrations at >20% efficiency in primary human T cells at the TRAC locus and at >60% efficiency in human iPSCs at the AAVS1 locus. Finally, we demonstrate that GMP clinical-manufactured T cells with ultra-large integrations are functional in vitro and in vivo. Overall, we identified optimal template architectures, delivery modes, and sequence design rules for ultra-large DNA integrations in both research and clinical settings to accelerate basic genetic research and next-generation cellular therapies.

genetics↗

bioRxiv2026

Haplotype-resolved Genome Assemblies of Hybrid Wheatgrass and Bluebunch Wheatgrass Reveal the Stepwise Polyploid Origin and Biased Subgenome Dominance

Concerns over climate change have intensified the demand for stress resistant crops like hybrid wheatgrass (HWG; Elymus hoffmannii, StStStStHH), a perennial forage species known for its exceptional salt and drought tolerance. However, hexaploidy and high heterozygosity have complicated efforts to resolve its genomic structure and evolutionary history. Here, we present high-quality, haplotype-resolved, chromosome-level genome assemblies for HWG (CDC Saltking) and its putative progenitor, bluebunch wheatgrass (Pseudoroegneria spicata, StSt). By integrating PacBio HiFi and ultra-long Oxford Nanopore sequencing with Hi-C scaffolding, we assembled the 10.7 Gb HWG genome into 21 pseudochromosomes per haplotype. Our phylogenomic analysis redefines the origin of the H subgenome, positioning it as an intermediate between Old-World Hordeum marinum (sea barley) and Hordeum brevisubulatum. Notably, we identified significant chromosomal rearrangements, including a unique duplication on St chromosome 4. Transcriptome analysis across multiple tissues revealed a pronounced expression dominance of the H subgenome. This dominance was not associated with reduced LTR density, suggesting that selective pressures for rapid adaptation of the latest subgenome entrant may drive its dominance. Finally, using the f-branch statistic, population genomic analysis of 189 accessions representing eight Elymus and Pseudoroegneria species revealed extensive reticulate evolutionary relationships and identified P. spicata as a major, asymmetric genetic donor within the wheatgrass complex. These resources provide a foundational framework for future genomic research and genetic improvement in grasses and for the introgression of stress-tolerance traits into cereal crops such as wheat. Key MessagesO_LIDevelopment of world-first high-quality chromosomal-level haplotype-resolved genome assemblies of hexaploid HWG and diploid progenitor, Pseudoroegneria spicata, enabled the identification of the subgenome origins. C_LIO_LIThis study resolved the evolutionary placement of the St genome and clarified the history of polyploidization and hybridization in HWG. C_LIO_LIHomeolog expression bias in the H subgenome likely reflects selective pressure favoring greater gene retention and upregulation of functionally important genes, thereby enhancing hybrid fitness. C_LIO_LIPopulation structure analysis distinctly differentiates P. spicata, E. repens, E. hoffmannii from other European Pseudoroegneria species. C_LIO_LIThe findings reveal the complex patterns of interspecific gene flow and population dynamics within the Elymus and Pseudoroegneria species. C_LI

genomics↗

bioRxiv2026

Structural Components for Calcitonin Gene-Related Peptide Signaling to Oligodendrocyte Precursor Cells

Oligodendrocyte precursor cells (OPCs) are unique glial cells that communicate bidirectionally with neurons. Neuronal inputs drive various OPC behaviors, including proliferation and differentiation, immunomodulation, blood brain barrier regulation, synapse engulfment and axonal remodeling. OPCs are implicated in numerous stress and pain conditions, where their involvement is likely driven by neuronal activity (ie. neurotransmitter and neuropeptide signaling). One neuropeptide causally involved in chronic pain and stress conditions is calcitonin gene-related peptide (CGRP). Here, we tested the hypothesis that OPCs receive direct inputs from CGRP-containing neurons in the adult brain. Using RNAscope, immunofluorescence and analysis of single-cell datasets, we find that OPCs express receptors for CGRP and we identify close spatial contacts between CGRP and OPCs, with nearly half of CGRP puncta occurring within 1 {micro}m of an OPC. Some of these contacts appear to be synaptic, with CGRP-OPC contacts colocalizing with the presynaptic protein Bassoon and the postsynaptic protein PSD-95. This work suggests the presence of both diffuse and more direct forms of CGRP signaling to OPCs, raising the importance of future experiments to identify both the mode of CGRP release onto OPCs and the functional effects of these different contact types.

neuroscience↗

bioRxiv2026

Quiescence improves Candida albicans survival of fungicidal drug exposure

Quiescence, defined as the reversible exit from mitotic division and proliferative growth, is the predominant state of all microbes. Despite its prevalence, the properties and consequences of quiescence in Candida albicans, an opportunistic fungal pathogen, remain largely unexplored. In this study, we characterized the morphological, molecular, and biophysical properties of quiescent C. albicans cells and assessed the effects of quiescence on antifungal drug efficacy. Quiescent cells that were induced via carbon starvation in rich and minimal media underwent distinct morphological changes upon entry into quiescence; this included an increase in cell buoyant density, altered fluidity of the cytoplasm and nucleus, and remodeling of mitochondria. Most C. albicans cells arrested in an unbudded G1/G0 state, although a significant fraction of cells had budded morphologies and 4N DNA content, indicating that they arrested at other cell cycle phases. Both budded and unbudded quiescent cells efficiently re-entered the cell cycle upon nutrient replenishment, with time-to-quiescence exit varying depending on the total nutritional quality of the medium. Quiescence was associated with large-scale gene expression remodeling, including downregulation of ribosomal biogenesis genes and upregulation of autophagy and stress response pathways. Notably, a greater proportion of quiescent cells than proliferative cells survived exposure to the commonly used antifungal drugs micafungin, caspofungin, and amphotericin B in genetically diverse strains. Thus, quiescence is a distinct cellular state with important implications for antifungal drug efficacy in C. albicans. Author SummaryWe show that Candida albicans, a common fungal pathogen, can enter a reversible, non-dividing state when starved of carbon. Starved cells become smaller and denser, reorganize their mitochondria, change how densely packed the inside of the cell and its nucleus are, and switch on stress-protection and internal recycling programs while reducing protein synthesis activity. Most cells have ceased to actively divide, but many retained budded shapes and could restart growth when nutrients returned; the timing of recovery depended on the nutritional environment in which quiescence was initiated. Critically, quiescent cells from laboratory and clinical strains exhibited greater survival than proliferative cells when exposed to widely used fungicidal drugs including micafungin, caspofungin, and amphotericin B. These findings indicate that quiescence is an active, adaptive physiological state that helps Candida albicans survive hostile environmental conditions such as temperature stress and drug exposure. Accounting for the metabolic state of fungal cells in diagnostics and drug development may improve treatment outcomes.

microbiology↗

bioRxiv2026

Longitudinal modality prediction learns gene regulatory patterns: insights from a single-cell competition

Simultaneous measurement of chromatin, transcriptomic, and proteomic features in single cells opens new avenues for modeling interactions between molecular layers during dynamic biological processes. Predicting one modality from another - such as inferring gene expression from chromatin profiles or protein abundance from RNA - has the potential to reveal regulatory relationships and enhance downstream analyses. However, conventional approaches for predicting gene regulation have largely failed and method development in modality prediction for regulatory inference has been limited. To explore effective modeling strategies and stimulate innovation, we generated a purpose-built longitudinal multimodal benchmarking dataset that captures early hematopoietic differentiation and organized the largest single-cell data competition to date, receiving over 27,000 submissions from 1,602 competitors worldwide. In our extensive analysis of the competition results, we demonstrated that top-performing approaches outperform state-of-the-art methods, and uncover how best-performing models captured biologically meaningful regulatory relationships between modalities. With ablation studies of the winning models, we identified feature-engineering strategies, model architectures and cross-validation schemes that are crucial for outstanding performance, and provide simplified, reproducible, light-weight code for state-of-the-art models. Together, the benchmark and analyses serve as an evaluation standard and guide future method development, including recently emerging foundation models, to advance our understanding of regulatory interactions in longitudinal, multimodal single-cell data.

bioinformatics↗

bioRxiv2026

Phyllosphere and rhizosphere microbiomes empower Nicotiana tobacum complex traits dissection and prediction

Understanding how plant-associated microbiomes interact with host genome variation to influence agronomic traits is essential for advancing microbiomeassisted crop improvement. In this study, we characterized the phyllosphere and rhizosphere microbiomes of 164 diverse Nicotiana tabacum accessions using 16S rRNA sequencing and integrated these data with host genomic variation and 22 agronomic traits. The two microbiomes exhibited distinct taxonomic structures, diversity patterns, and predicted metabolic functions. Microbiome genomewide association studies identified extensive host genetic control over microbial abundance, including 49 shared genomic loci that explained nearly half of the heritable variation in both microbiomes. Microbiomewide association studies revealed biologically meaningful associations between specific ASVs and agronomic traits. However, network analysis demonstrated that microbial subcommunities, rather than individual taxa, contributed substantially to phenotypic variation. Then, colocalization analysis further identified genetic variants jointly influencing microbial abundance and metabolite traits, highlighting potential host-microbe-trait causal links. Incorporating microbiome data into genomic selection models, we successfully improved prediction accuracy for several traits, especially plant architecture and flowering. Together, this work provides a comprehensive populationlevel framework linking host genetics, microbiome composition, and agronomic traits in tobacco, offering new insights for microbiomeinformed breeding strategies.

plant biology↗

bioRxiv2026

Geometric-aware and interpretable deep learning for single-cell batch correction via explicit disentanglement and optimal transport

Single-cell RNA sequencing enables high-resolution characterization of cellular heterogeneity, yet integrating datasets from diverse sources remains challenging due to batch effects. Current methods rely on implicit feature disentanglement and and lack geometric constraints, often result in under-correction, over-correction, or compromised biological fidelity. Here, we present iDLC, an interpretable deep learning framework that performs dual-level correction through explicit feature disentanglement and optimal transport-regularized adversarial alignment. iDLC separates biological and technical components within a structured latent space, then leverages high-confidence mutual nearest neighbor pairs to guide geometrically constrained distribution alignment. Systematic evaluation across pancreatic cancer datasets with varying batch effect intensities, multi-source human immune cells, and large-scale cross-species atlases demonstrates that iDLC robustly eliminates complex batch effects while preserving fine-grained cell subtypes, continuous developmental trajectories, and rare populations. The framework scales efficiently to datasets exceeding one million cells and consistently outperforms existing methods in both batch correction and biological conservation metrics. iDLC provides a principled and reliable tool for constructing unified single-cell reference atlases across diverse experimental conditions and biological systems.

bioinformatics↗

bioRxiv2026

Nonanticoagulated Heparin Derivatives Mediate Goblet Cell Differentiation to Restore the Mucosal Barrier for Ulcerative Colitis Therapy

Epithelial mucus barrier dysfunction is a pathological hallmark of ulcerative colitis (UC), yet current clinical therapeutic strategies primarily suppress inflammation, lacking reliable approaches for restoration of the mucosal layer. Here, through a systematic screen of our established library of deanticoagulated heparins, we identified NALHP, a non-anticoagulant low-molecular-weight heparin derivative, and its representative fraction S6 as orally active epithelial repair-promoting glycans. NALHP/S6 restored crypt architecture, mucus production and epithelial barrier integrity in experimental colitis. In UC patient-derived colonic organoids, NALHP/S6 reduced aberrant stem/proliferative programs while promoting secretory, absorptive and junctional maturation. Single-cell transcriptomics and temporal validation identified a transient repair-secretory transitional state (RSTS) positioned between classical Wnt-associated stemness and mature barrier-forming epithelial states. Transcriptomic analysis revealed coordinated attenuation of Wnt and Notch signaling, whereas pharmacological reactivation of these pathways opposed NALHP/S6-induced epithelial state progression. These findings define mucosal repair as a regulated epithelial-state transition and identify NALHP/S6 as glycan-based modulators capable of restoring this progression in UC epithelium.

pathology↗

bioRxiv2026

High-quality genome assemblies of diploid Bromus species enhance understanding of genome complexity and uncover large DNA satellite structures.

Genus Bromus includes important cool-season forage grasses, but large genome sizes and complex ploidy hinder genomic studies. Here we carried out long read sequencing of two diploid genomes, Bromus riparius and Bromus squarrosus, generating highly contiguous assemblies with contig N50 values of 294.76 Mb and 98.78 Mb, respectively. These assemblies uncovered high-order centromeric repeats and two unique large sub-telomeric repeats on chromosome 5 and 7. Repeat expansion in Bromus appears relatively recent compared to speciation events ([~]9.75 million years ago); yet strong synteny persists across species. Transposable elements such as Angela, SIRE, Athila, CRM, and Retand were identified as major contributors to genome expansion in related Bromus species. Population structure analysis resolved six major subpopulations, with wild relatives exhibiting a higher genetic divergence than cultivated types. Hybrid bromegrass lines showed a higher proportion of genomic contribution from B. inermis than B. riparius. Together, these genomic resources provide a foundation for investigating traits of interest and advancing bromegrass breeding.

genomics↗

bioRxiv2026

Glucokinase links metabolism and lineage plasticity in neuroendocrine prostate cancer via interaction with AKT1

Cancer cells frequently rewire their metabolism to sustain growth and survival under stress. Despite the critical role of metabolic adaptation in tumorigenesis, how specific metabolic enzymes regulate lineage plasticity remains unclear. Here, through FDG-PET imaging and transcriptomic analyses, we reveal markedly elevated glucose uptake in neuroendocrine prostate cancer (NEPC) and identify glucokinase (GCK) as a MYCN-induced metabolic enzyme. Beyond its metabolic role, GCK is indispensable for maintaining the neuroendocrine lineage of prostate cancer cells by establishing a functional circuit with AKT1 through reciprocal regulation--AKT1 binds and phosphorylates GCK at S373, whereas GCK phosphorylates AKT1 at S473. Pharmacological disruption of this AKT1-GCK axis suppresses tumor growth in NEPC mouse models and patient-derived xenografts. Altogether, our findings uncover both the metabolic and noncanonical kinase functions of GCK and establish the AKT1-GCK axis as a key link between metabolic reprogramming and neuroendocrine lineage transition in prostate cancer.

cancer biology↗

bioRxiv2025

ERAD Activity Distinguishes the Functional Heterogeneity of Hematopoietic Stem Cells

Hematopoietic stem cells (HSCs) rely on precisely controlled proteostasis to sustain lifelong self-renewal, yet whether intrinsic proteostatic characteristics can prospectively define functional diversity within the HSC pool remains unknown. In this study, we developed a dual-fluorescence reporter system to visualize endoplasmic reticulum-associated degradation (ERAD) activity in vivo and discovered that ERAD activity can prospectively predicts the long-term reconstitution potential of HSCs. Remarkably, ERAD states were maintained through self-renewal, revealing an inheritable "proteostatic memory" within the HSC pool. Transcriptomic and functional analyses identified SOCS2 as a key regulator of this process: SOCS2 inhibits JAK2 signaling to sustain ERAD activity, whereas hyperactive JAK2 interacts with the ERAD E3 ligase Hrd1 and suppresses VCP-mediated misfolded substrate. These findings define a SOCS2-JAK2-ERAD axis that connects cytokine signaling to intrinsic proteostasis remodeling, establishing ERAD activity as a predictive and heritable marker of HSC function and providing a conceptual framework for understanding hematopoietic stem cell heterogeneity.

cell biology↗

bioRxiv2025

Gut Microbiota-derived Adenosine Determines the Efficacy of Electroconvulsive Therapy for Depression

Electroconvulsive therapy (ECT) is a final procedure for major depressive disorders (MDD). However, the effectiveness of ECT in treating MDD patients varies. Here we identified gut microbiota as a potential restraining factor of ECT efficacy. By using a 5-day electroconvulsive shock (ECS) in depression mouse model of chronic restraint stress (CRS), it was observed that the antidepressant effect of ECS was suppressed after antibiotics (ABX)-induced microbiota dysbiosis, which also resulted in elevated c-Fos expression of CRH neurons in paraventricular nucleus of hypothalamus (PVN) and increased serum corticosterone levels after ECS. Metabolomic analysis revealed the critical involvement of microbiota associated purine metabolism, and the supplement of gut microbiota-derived adenosine was able to recover the antidepressant effect of ECS in ABX-treated CRS mouse model. Based on the neural tracing from colon to brain and the immunofluorescence staining, it was surmised a gut-brain axis originated from Adora1-expressing cells in colon mediate this biological process. Furthermore, adenosine supplement alleviated the further deterioration of post-ECS memory loss and impairment of synaptic plasticity induced by ABX-treatment as well. Our findings suggest a potential role of microbial adenosine metabolism in ECT efficacy determination and side effect protection, highlights potential application of adenosine supplement in antidepressant therapies of those depression patients with microbiota dysbiosis.

systems biology↗

bioRxiv2025

Contralateral-Ipsilateral Segregation as a Conserved Principle of the Visual Corpus Callosum

How the brain maintains distinct information streams within dense white matter is a fundamental question. We investigated whether the visual corpus callosum transmits information via segregated "parallel wires" or mixed pathways. This distinction is critical: a mixed architecture would render the signals origin ambiguous, whereas a segregated arrangement implies that spatial position tracks the direction of information flow. Using high-field fMRI and Bayesian modeling in humans, we demonstrate a segregated architecture featuring distinct contralateral and ipsilateral channels. This functional segregation mirrors a precise anatomical arrangement in mice, where dual-color viral tracing and light-sheet microscopy reveal that callosal axons remain spatially segregated in distinct laminae after crossing the midline. Our findings establish a conserved "parallel wires" principle of callosal organization, providing a new framework to decode directional information flow and assess pathway-specific damage in neurological disease.

neuroscience↗

bioRxiv2025

Geomagnetic and visual cues guide seasonal migratory orientation in the nocturnal fall armyworm, the worlds most invasive insect

The mechanisms guiding nocturnal insect migration remain poorly understood. Although many species are thought to use the geomagnetic field, the sensory basis of magnetic orientation in insects has yet to be clarified. We developed an indoor experimental system to investigate the integration of geomagnetic and visual cues in the seasonal orientation of a globally distributed pest moth, the fall armyworm (Spodoptera frugiperda), a highly invasive species which in the past decade has colonized almost all potentially habitable regions of the globe. Our results demonstrate that fall armyworms require both geomagnetic and visual cues for accurate migratory orientation, with visual cues being indispensable for magnetic orientation. When visual and geomagnetic cues are placed in conflict moths become disoriented, although not immediately, indicating that sensory recognition of the conflict requires time to process. We also show that the absence of visual cues leads to a significant loss of flight stability, which likely explains the disruption in orientation. Our findings highlight that visual cues are critical for stable magnetic orientation in the fall armyworm, offering a basis for future investigations of visual-magnetic integration in noctuid migrants.

animal behavior and cognition↗

bioRxiv2025

Validation of Solvent Proteome Profiling for Antimalarial Drug Target Deconvolution

Malaria remains a global health threat, with rising drug resistance accelerating the urgent need for new therapeutics. Target elucidation is a critical step in antimalarial drug discovery, enabling a deeper understanding of the molecular mechanisms of action of both existing and novel compounds. This study validates solvent-induced proteome profiling (SPP) as a proteomics-based approach for identifying drug-protein interactions in Plasmodium falciparum. SPP detects shifts in protein stability induced by ligand binding, allowing the identification of drug target/s without the need for compound modifications. Here, we successfully generated solvent denaturation curves for the P. falciparum proteome, and demonstrated the utility of SPP with five antimalarial compounds: pyrimethamine, atovaquone, cipargamin, MMV1557817 and OSM-S-106. In addition to measuring each compounds impact across the full denaturation curve, investigating protein levels at individual solvent percentages preserved specific stability changes that would otherwise be masked in pooled analyses performed by integral SPP. This strategy was critical for the identification of the cipargamin target, non-SERCA-type Ca2+-transporting P-ATPase (PfATP4). Notably, we propose live-cell treatment SPP as a novel approach, demonstrating its ability to identify the validated target of pyrimethamine, bifunctional dihydrofolate reductase-thymidylate synthase (PfDHFR), with high specificity. We also introduced the novel one-pot mixed-drug SPP which enables the evaluation of multiple drugs within a single lysate and experimental setup. This alternative method simplifies the experimental workflow and includes positive controls to affirm the performance of the experiment. Overall, this study demonstrates that SPP can be successfully applied in both lysates and live cells to elucidate drug targets in P. falciparum, as well as providing additional information regarding the mechanisms of drug action, offering insights for the optimisation of existing antimalarials and the development of novel therapies. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=137 SRC="FIGDIR/small/670428v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@b83c75org.highwire.dtl.DTLVardef@1895f23org.highwire.dtl.DTLVardef@1c51ba0org.highwire.dtl.DTLVardef@198c822_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

bioRxiv2025

Measure Sodium Transport in Cells with NMR

Sodium ions (Na+) are fundamental to numerous physiological functions, such as maintaining electrolyte balance, enabling nerve impulse transmission, and facilitating muscle contraction. Dysregulation of Na+ transport across cell membranes is implicated in a range of health issues, including metabolic syndromes, neurological conditions, and cardiovascular diseases. However, current methods for assessing cellular Na+ activity often face limitations; they can be invasive or fail to capture dynamic changes. In this study, we introduce a non-invasive 23Na nuclear magnetic resonance (NMR) methodology designed to directly quantify the transport rate of sodium ions in living cells. Our technique integrates relaxation exchange spectroscopy (REXSY) with a multi-site exchange model, enabling the investigation of Na+ transport dynamics on a timescale of sub-seconds. A key advantage is its ability to differentiate between intracellular and extracellular Na+ pools based on the endogenous NMR relaxation difference, thereby avoiding the need for potentially disruptive exogenous reagents. Experiments conducted on human cell lines successfully demonstrated the techniques capacity to distinguish between various physiological states, such as when ion channels are pharmacologically blocked or activated. The resulting measurements of Na+ transport rates and intracellular Na+ fractions show a clear correlation with cellular metabolic activity, offering valuable quantitative markers for monitoring transmembrane ion dynamics in vitro.

cell biology↗