Biology subjects

Nguyen, D. T.

Publications and source records attributed to Nguyen, D. T..

At least 19 recordsLinked to original sources

bioRxiv2026

A Practical Framework for Constructing Population-Specific and Alternate-Contig-Aware Genome References: A case study of Vietnam

Current studies in human genomics typically rely on the standard genome reference GRCh38 which is known to be biased toward populations of European ancestry and therefore has limitations when applied to other populations. Although various graph-based pangenome references were constructed for several populations to deal with this bias, their usage in practice is currently still limited compared to linear genome references. Here we present a framework for constructing a population-specific genome reference using GRCh38 as backbone with alternate-contig awareness to enhance genomic data analysis in the target population. We demonstrated the advantages of our framework using both public and in-house Vietnamese whole-genome sequencing (WGS) datasets. Genomic variants derived from high-coverage WGS data of the 1000 Vietnamese Genomes Project (VN1K) were imported into our framework to build a Vietnamese-specific Genome Reference (VGR). VGR was then compared to GRCh38 in read alignment and variant calling using high-coverage WGS data of 99 Vietnamese individuals (KHV) from the 1000 Genomes Project (1kGP). Using Omni array genotyping data from 99 KHV samples as an independent benchmark, we found that VGR improved variant-calling precision and reduced false-positive calls compared to GRCh38. Our framework could be easily used for other populations as long as they have a variant database similar to VN1K. Our code is publicly available at github.com/VinGenome/VGR

genomics↗

bioRxiv2026

PrimeKG-Plus: a literature-derived expansion of a multimodal precision medicine knowledge graph

BackgroundDisease-centered knowledge graphs (KGs) support drug repurposing and precision medicine research, yet many remain static after release while primary databases and literature continue to expand. PrimeKG (Precision Medicine Knowledge Graph) is a widely used multimodal KG providing a holistic view of diseases. However, its public release reflects a June 2021 data cutoff, omitting several years of subsequent data growth. This lag is especially consequential for rare diseases, where mechanistic and therapeutic evidence often remains scattered across publications rather than structured resources. FindingWe present PrimeKG-Plus, a refreshed, rare-disease-enriched release of PrimeKG, rebuilt from all twenty original data resources updated to their December 2025 releases and three additional resources: OpenTargets, RepurposeDrugs, and nSIDES. Beyond synchronizing biomedical databases, PrimeKG-Plus captures approximately five years of previously unavailable rare-disease knowledge from the biomedical literature, curated from 637 PubMed abstracts and PubMed Central full-text articles using a language-model-assisted workflow focused on four rare neurological disorders: Canavan disease, Niemann-Pick disease type C, Tay-Sachs disease, and Batten disease. Extracted relations were refined through entity normalization, UMLS synonym mapping, embedding-based similarity ranking, and human expert review. Network topology analysis showed improved indirect drug-disease connectivity across three to six hops and added 447,288 drug-protein-disease paths linking previously unreachable drug-disease pairs. Temporal validation using drug approval records identified 55 molecular entities approved after the original PrimeKG June 2021 cutoff, 46 of which were absent from the original graph. ConclusionPrimeKG-Plus restores the temporal relevance of PrimeKG, providing an updated resource for drug repurposing, rare-disease research, and downstream machine-learning applications.

bioinformatics↗

bioRxiv2026

Ex Vivo Culture of Patient-Derived Primary, Metastatic, and Post-Mortem Lung Cancer Reveals Targetable States of EMT and Metabolic Plasticity

Lung cancer is a highly heterogeneous disease and remains the leading cause of cancer-related mortality worldwide. While mouse models and patient-derived organoids have advanced our understanding of lung cancer, key interactions within the tumor microenvironment (TME) remain poorly characterized. We developed microtumor models from lung adenocarcinoma (LUAD) and small cell lung cancer (SCLC) using mouse and patient samples, including surgical resections and rapid autopsy specimens. Microtumors preserve structural, cellular, and molecular features of the native TME, enabling mechanistic studies of tumor progression ex vivo. Multi-omics analyses of LUAD microtumors revealed progression-associated changes, including increased epithelial-to-mesenchymal transition (EMT) and metabolic reprogramming toward fatty acid synthesis. Pharmacologic inhibition of fatty acid synthesis through ACC1/2 reduced proliferation in patient-derived microtumors, identifying a targetable vulnerability. This platform provides a robust system for studying tumor progression, therapeutic response, and resistance mechanisms in lung cancer, including culturing postmortem specimens that are not accessible in current models.

cancer biology↗

bioRxiv2026

Substrate-dependent crosslinking by the cytochrome P450 from aminopyruvatide biosynthesis

Cytochrome P450s catalyze an array of reactions including crosslinking of aromatic side chains in the biosynthesis of ribosomally synthesized and post-translationally modified peptides (RiPPs). ApyO is a cytochrome P450 that forms a C-C bond between two tyrosines in a YLY motif in the substrate ApyA, the precursor peptide of the RiPP aminopyruvatide. We utilized cell-free translation to generate ApyA variants and probe the substrate tolerance of ApyO. Through Alphafold-based modelling and in vitro assays, we show that ApyO accepts the 10 C-terminal residues of ApyA and requires a conserved Arg/Lys in the substrate. Inspired by substrate sequences in orthologous biosynthetic gene clusters, we substituted one of the tyrosine residues with a tryptophan and observed that ApyO catalyzed formation of an N-C bond between the indole of Trp and C{epsilon}2 of Tyr. ApyO unexpectedly catalyzed formation of a C-O bond between the two tyrosine residues when we substituted the leucine residue in the YLY motif with tyrosine or tryptophan. A peptide containing a biaryl linkage and C-terminal aminopyruvate displayed sub-nanomolar inhibition of select proteases with the aminopyruvate group critical for activity. Overall, this study demonstrates plasticity in the manner of macrocyclization catalyzed by the P450 ApyO.

biochemistry↗

bioRxiv2026

Structural variants contribute substantially to complex trait heritability

Despite accumulating evidence that structural variants (SVs) exert disproportionate functional effects, their genome-wide contribution to complex trait heritability has not yet been systematically quantified. Here, we introduce MiXeRSV, a tool that integrates long-read-derived SVs from existing reference catalogs with genome-wide association summary statistics to quantify SV heritability and enrichment. Applying MiXeR-SV to 105 complex traits, we identify 31 traits with significant enrichment (Bonferroni-corrected P < 4.8 x 10-4), with SVs explaining up to 32% of total heritability, despite comprising only 0.6% of the analyzed variants. Enrichment is most extensive in hematological, metabolic/biomarker, and cancer traits, trait-specific in neuropsychiatric and cardiometabolic phenotypes, and observed across all anthropometric traits, albeit with modest effect sizes, consistent with their highly genetic architecture. These findings are robust across two independent SV reference panels built from complementary long-read and graph-based variant catalogs, with 93.5% of significant traits consistent between technologies. Furthermore, incorporating SV architecture into heritability models consistently increases total heritability estimates in enriched phenotypes, with SV heritability proportions correlating with the gap between SNP-based and twin heritability estimates across traits. Cross-ancestry replication in Biobank Japan confirms enrichment patterns. Our quantification of SVs contributions to genetic architectures has significant implications for genetic prediction and fine-mapping of human complex traits and common diseases.

genetics↗

bioRxiv2025

Collagen remodeling promotes a GPCR-mediated mechanosensory immune checkpoint in ADGRG1+ CD8+ T cells and serves as a spatial biomarker of response to immunotherapy

Accessibility of immune cells to the tumor microenvironment (TME) in many solid tumors can be influenced by extracellular matrix (ECM) deposition, organization, and remodeling within tumor stroma. Specifically, lysyl hydroxylase-2 (LH2)-catalyzed lysine hydroxylation in type-I collagen telopeptides leads to formation of intermolecular collagen cross-links creating a stiffened and proteolytically resistant, stable ECM. Advanced head and neck squamous cell carcinomas (HNSCC) frequently exhibit desmoplasia with elevated LH2 expression, and Immune-checkpoint (ICI) therapy is effective in only <20% patients, suggesting that ECM remodeling mechanistically governs the composition and function of TME infiltrates. We show that elevated LH2 and collagen alignment promotes stromal accumulation of CD8 T-cells, and poor response to ICI in HPV-HNSCCs. Integration of clinical biopsies, transcriptomic datasets, and an immunocompetent syngeneic mouse model revealed that aligned collagen spatially restricts adhesion G protein-coupled receptor positive (ADGRG1) CD8 T-cells to activate a non-canonical GPCR-mediated mechanosensory program that drives dysfunction and exhaustion. Statement of significanceDesmoplasia is common in solid tumors, and immune checkpoint inhibitors benefit only some patients. Current biomarkers like PD-L1 and TMB have limited value. Our findings reveal a previously unrecognized collagen-ADGRG1 mechanosensory immune checkpoint, offering a clinically tractable, spatially resolved biomarker to better stratify patients for immunotherapy.

cancer biology↗

bioRxiv2025

Detection of a novel Puccinia coronata f. sp. avenae genotypic lineage in Australia during the 2024 oat growing season

Crown rust, caused by Puccinia coronata f. sp. avenae (Pca), remains a persistent threat to oat production in Australia. To monitor recent shifts in virulence and population structure, 30 Pca isolates collected during the 2024 growing season across major Australian oat-producing regions were analysed. Virulence analysis of 30 isolates using 52 oat differential lines identified 25 unique races that were not detected in previous years. Whole-genome sequencing of 28 of these isolates were analysed in the context of a broader historical Australian and international genomic datasets including isolates from Taiwan, South Africa, USA. Results confirmed the uniqueness of the Australian Pca population and revealed well-established genotypic lineages persisting over multiple years, with L18 and L16 being dominant. Notably, L16 was again present in Western Australia after being undetected in 2023, while L18 maintained its prevalence for a third consecutive season. Beyond these dominant groups, phylogenetic analysis and a k-mer containment analysis also identified a novel and genetically distinct lineage, designated as L19, represented by one isolate collected in WA. To add to the characterisation of lineage L19, we recorded virulence phenotypes on a small collection of current commercial cultivars. These findings enhance understanding of Pca diversity and emphasise the importance of surveillance approaches that integrate phenotypic and genomic surveillance.

pathology↗

bioRxiv2025

Graphene nanoedge electronics for monolithic and chronic recording of local microcircuits at neuronal density

High-density single-unit recording among closely spaced neurons over long durations is crucial for understanding the cellular-level functional architecture of the brain. Existing brain probes, however, either laterally sample neurons far more sparsely than neuronal density in the same cortical layer or suffer from long-term instability due to electrode modification, preventing precise neuron-to-neuron interrogation in local microcircuits. Here, we report a monolithic graphene-edge probe (NeuroEdge) that achieves single-unit recording at neuronal density (16 electrodes within 100 {micro}m diameter). We fabricate NeuroEdge using self-assembled reduced graphene oxide nanoflakes to form an electrochemically active tip consisting of exposed graphene nanoedges and electrolyte-filling nanotunnels, achieving an ultralow specific impedance of 20 M{Omega} {micro}m2. In vivo experiments over 5 months demonstrate recording at a high signal-to-noise ratio (>20 dB) and reliable interrogation of neighboring neurons. We also show that NeuroEdge can record from a single auditory cortical layer and reveal heterogeneities in the acoustic frequency response and dynamic connectivity among neighboring neurons. NeuroEdge provides a tool for precisely interrogating local microcircuits at the density of neurons in the brain.

bioengineering↗

bioRxiv2025

Aminoacyl-tRNA specificity of a ligase catalyzing non-ribosomal peptide extension

Peptide aminoacyl-transfer ribonucleic acid ligases (PEARLs) are amide bond-forming enzymes that extend the main chain of peptides using aminoacyl-tRNA (aa-tRNA) as a substrate. In this study, we investigated the substrate specificity of the PEARL BhaBCAla from Bacillus halodurans, which utilizes Ala-tRNAAla. By leveraging flexizyme, a ribozyme capable of charging diverse acids onto a desired tRNA, we generated an array of aa-tRNAs in which we varied both the amino acid and the tRNA to dissect the substrate scope of BhaBCAla. We demonstrate that BhaBCAla catalyzes peptide extension with non-cognate proteinogenic and non-canonical amino acids, hydroxy acids, and mercaptocarboxylic acids when attached to tRNAAla. For most of these, the efficiency was considerably reduced compared to Ala, indicating the enzyme recognizes the amino acid. By varying the different parts of the tRNA, enzyme specificity was shown to also depend on the acceptor stem and the anticodon arm of the tRNA. These findings establish the molecular determinants of PEARL specificity and provide a foundation for engineering these enzymes for broader applications in peptide synthesis.

biochemistry↗

bioRxiv2025

Imputation and polygenic score performance of low coverage whole-genome sequencing and genotyping arrays in diverse human populations

Genome-wide association studies and polygenic score analysis rely on large-scale genotypic data, traditionally obtained through SNP arrays and imputation. However, low coverage whole-genome sequencing has emerged as a promising alternative. This study presents a comprehensive comparison of imputation accuracy and polygenic score performance between eight high-performance genotyping arrays and six low coverage whole-genome sequencing coverage levels (0.5-2x) across diverse populations. We analyze data from 2,504 individuals in the 1000 Genomes Project using a 10-fold cross-imputation strategy to evaluate imputation accuracy and polygenic score performance for four complex traits. Our results demonstrate that low-pass whole-genome sequencing performs competitively with population-specific arrays in both imputation accuracy and polygenic score estimation. Interestingly, low coverage whole-genome sequencing shows superior performances compared to arrays in underrepresented populations and for rare and low-frequency variants. Our findings suggest that low coverage whole-genome sequencing offers a flexible and powerful alternative to genotyping arrays for large-scale genetic studies, particularly in diverse or underrepresented populations.

genomics↗

bioRxiv2025

A Nextflow pipeline for molecular quantitative trait loci mapping in small sample size datasets with an application in Atlantic salmon

BackgroundMolecular quantitative trait loci (molQTL) mapping, particularly for gene expression and chromatin accessibility, provides crucial insights into the regulatory and functional potential of genetic variation. While significant progress has been made in humans and model organisms, aquatic genomics remains underexplored due to the large sample sizes typically required for statistical power. ResultsIn this work, we enhance the scalability, reproducibility, and accessibility of the well-established RASQUAL method, which efficiently detects molQTLs in small datasets, by leveraging the Nextflow workflow framework. This adaptation, named nf-RASQUAL, supports fully automated QTL mapping and incorporates a robust, comprehensive multiple-testing correction process. We apply the pipeline to a comprehensive multi-omics dataset from Atlantic salmon, identifying numerous significant expression and chromatin accessibility QTLs across multiple tissues. Our analysis reveals that a large proportion of lead variants for these loci reside in non-coding regions, with caQTL lead SNPs more likely to disrupt transcription factor motifs. Additionally, the enriched colocalization of eQTL and caQTL lead SNPs in brain, liver, and gonad tissues suggests shared regulatory mechanisms. ConclusionsThese findings highlight the scalability and utility of nf-RASQUAL for advancing genetic regulation research in aquaculture, facilitating molQTL studies in less-explored species, and improving our understanding of molecular phenotypes shaped by genetic diversity.

genomics↗

bioRxiv2025

Global genome analysis identifies glycolipids and lipoteichoic acid alanylation as contributors to Group B streptococcal diabetic wound infection

Individuals with diabetes frequently develop chronic, hyper-inflammatory, non-healing wounds, which are the leading cause of all non-traumatic amputations. Group B Streptococcus (GBS) is a prominent bacterium isolated from diabetic wound infections and in a murine model of diabetic wound infection, GBS stimulates an influx of neutrophils into the wound. Utilizing a transposon mutant screen, we identified 291 bacterial genes required for fitness during diabetic wound infection including enzymes involved in glycolipid biosynthesis and lipoteichoic acid (LTA) alanylation. GBS mutants lacking either LTA alanylation ({Delta}dltA) or all glycolipids ({Delta}iagB) are attenuated in a murine diabetic wound infection. GBS induces primary and secondary degranulation in primary human neutrophils and the {Delta}iagB mutant is significantly more susceptible to neutrophil killing by cationic antimicrobial peptides and reactive oxygen species than {Delta}dltA. Finally, we found that depletion of neutrophils led to significantly greater bacterial recovery, highlighting the importance of neutrophil defense during diabetic wound infection.

microbiology↗

bioRxiv2025

Mechanical Artifacts During Transcranial Focused Ultrasound Mimic Biologically Evoked Responses

Low-intensity transcranial focused ultrasound stimulation (tFUS) has emerged as a promising technique for non-invasive neuromodulation, offering deep brain penetration and high spatial precision. However, the electrophysiological effects of tFUS remain poorly understood, in part due to challenges distinguishing genuine neural responses from mechanical artifacts. Here we investigated the electrophysiological signatures captured during tFUS of the anesthetized rat hippocampus using silicon microelectrodes. We observed a strong, stereotyped local field potential (LFP) response that was time-locked to the onset and offset of sonication and resembled sensory-evoked potentials. Critically, the same waveform was observed in euthanized animals, confirming a non-biological, artifact-driven origin. The artifact scaled with acoustic intensity and was most pronounced under continuous-wave sonication. These findings suggest that electrode movement induced by ultrasound can generate artifactual LFP signals that closely mimic authentic neural responses. Our results underscore the need for caution when interpreting in situ electrophysiological recordings during tFUS and advocate for alternative, artifact-resistant readouts such as fiber photometry to unambiguously detect neuromodulatory effects.

neuroscience↗

bioRxiv2025

VN1K: a genome graph-based and function-driven multi-omics and phenomics resource for the Vietnamese population

Vietnam, the 16th most populated nation, remains profoundly underrepresented in global genomic databases. Here, we present VN1K, a first-ever comprehensive and well-curated resource of multi-omics data with a wide-range of phenotypic information of 1,011 unrelated Vietnamese individuals. High-depth short-read whole-genome sequencing data were generated for all samples along with various - omic data, including microarray, long-read whole-genome sequencing, and RNA sequencing. Using a high-sensitivity variant detection pipeline, which included a pangenome graph reference and a deep-learning framework, we identified nearly 40 million variants of which 8.5 million are novel with nearly 900 thousand short insertions/deletions and 39 thousand structural variants. Specifically, VN1K featured a first-ever whole-genome methylation profile based on long read sequencing. A genotype imputation panel was also created with the highest accuracy on the Vietnamese population. Variants with significantly different allele frequencies in the Vietnamese population compared to others were found to be functionally significant, especially in genes associated with immune diseases (HLA-B, KIR3DL3, KIR2DL1, KIR2DL4) or drug responses (CYP2C19, CYP2D6, VKORC1, CYP2B6). We were also able to map various loci related to hepatitis B virus infection as well as six disease traits, including triglyceride levels, LDL-C, serum glucose levels, HbA1c, and levels of two liver enzymes (ALT and AST). VN1K dataset is accessible via genome.vinbigdata.org, an integrated platform with both linear and graph-based genome browser for facilitating data exploration, research, and applications in precision medicine.

genomics↗

bioRxiv2025

Sequence-based chromatin activity modeling and regulatory impact prediction of genetic variants in farmed animals using deep learning

Non-coding genomic variations are crucial for the genetic regulation of traits; how-ever, their functional impact in farmed animals remains underexplored due to lim-ited genomic resources and the absence of tailored computational tools. Here, we present a deep learning-based framework that utilizes functional genomics data to generate genome-wide predictions of the regulatory impact of non-coding vari-ants in cattle, chicken, pig, and Atlantic salmon. By leveraging chromatin profiles such as ATAC, DHS, and ChIP-seq data, we train and optimize separate deep networks for each species, achieving robust sequence modeling accuracy specific to each. Motif analysis confirms that the models capture regulatory grammar, while in silico saturation mutagenesis experiments provide meaningful interpretations of the functional impact of putative causal variants. Furthermore, functional scores derived from these models predict eQTL causal variants and enhance genomic prediction performance. Our findings highlight the transformative potential of se-quence to function models in prioritizing causal variants and improving genomic prediction for livestock and aquaculture.

genomics↗

bioRxiv2025

Characterization of the Cellular Immune Response to Group B Streptococcal Vaginal Colonization

IntroductionGroup B Streptococcus (GBS) asymptomatic colonizes the female genital tract (FGT) but can contribute to adverse pregnancy outcomes including pre-term birth, chorioamnionitis, and neonatal infection. We previously observed that GBS elicits FGT cytokine responses, including IL-17, during murine vaginal colonization; yet the anti-GBS cellular immune response during colonization remained unknown. We hypothesized that GBS may induce cellular immunity, resulting in FGT clearance. MethodsHerein, we utilize depleting antibodies and knockout mice and performed flow cytometry to investigate cellular immunes responses during GBS colonization. ResultsWe found that neutrophils (effectors of the IL-17 response) are important for GBS mucosal control as neutrophil depletion promoted increased GBS burdens in FGT tissues. Flow cytometric analysis of immune populations in the vagina, cervix, and uterus revealed, however, that GBS colonization did not induce a marked increase in FGT CD45+ immune cells. We also found that that V{gamma}6+ {gamma}{delta} T cells comprise a primary source of FGT IL-17. Finally, using knockout mice, we observed that IL-17-producing {gamma}{delta} T cells are important for the control of GBS in the FGT during murine colonization. ConclusionsTaken together, this work characterizes FGT cellular immunity and suggests that GBS colonization does not elicit a significant immune response, which may be a bacterial directed adaptive outcome. However, certain FGT immune cells, such as neutrophils and {gamma}{delta} T cells, contribute to host defense and control of GBS colonization.

immunology↗

bioRxiv2024

Active Remote Focus Stabilization in Oblique Plane Microscopy

Light-sheet fluorescence microscopy (LSFM) has demonstrated great potential in the life sciences owing to its efficient volumetric imaging capabilities. For long term imaging, the light-sheet typically needs to be stabilized to the detection focal plane for the best imaging results. Current light-sheet stabilization methods rely on fluorescence emission from the sample, which may interrupt the scientific imaging and add to sample photobleaching. Here we show that for oblique plane microscopes (OPM), a subset of LSFM where a single primary objective is used for illumination and detection, light-sheet stabilization can be achieved without expending sample fluorescence. Our method achieves ~43nm axial precision and maintains the light-sheet well within the depth of focus of the detection system for hour-long acquisition runs in a lab environment that would otherwise detune the system. We demonstrate subcellular imaging of the actin skeleton in melanoma cancer cells with a stabilized OPM.

biophysics↗

bioRxiv2024

Surface remodeling and inversion of cell-matrix interactions underlies community recognition and dispersal in Vibrio cholerae biofilms

Biofilms are ubiquitous surface-associated bacterial communities embedded in an extracellular matrix. While it is commonly assumed that biofilm-dwelling cells are glued together by the matrix, how the cell-matrix interaction depends on the specific biochemistry of the matrix components and how this interaction varies during biofilm growth remains unclear. Here, we investigated cell-matrix interactions in Vibrio cholerae (Vc), the causative agent of cholera. We combine genetics, microscopy, simulation, and biochemical tools to show that Vc cells are not attractive to Vibrio polysaccharide (VPS), the main matrix component, but they can be bridged with each other and to the VPS network through crosslinking by Bap1. Downregulation of VPS and surface trimming by the polysaccharide lyase RbmB cause surface remodeling as biofilms age, shifting the nature of cell-matrix interactions from attractive to repulsive and facilitating cell dispersal as aggregated groups. Our results suggest a new conceptual model in understanding the intricate cell-matrix interaction as the major driver for biofilm development, which is potentially generalizable to certain other biofilm-forming species and exopolysaccharides.

biophysics↗