Biology subjects

Hong, M.

Publications and source records attributed to Hong, M..

At least 19 recordsLinked to original sources

bioRxiv2026

An atlas of eukaryotic centromere architecture reveals recurrent evolutionary dynamics

Centromeres evolved at the root of eukaryotes to segregate chromosomes during cell division. Despite their ancient origin, centromeric DNA sequences evolve rapidly and adopt diverse architectures, including point centromeres, satellite arrays, transposon clusters, and holocentrics. To analyse centromere evolution at a broad scale, we characterised architectures across 325 diverse Darwin Tree of Life genome assemblies. Centromere architecture is evolutionarily labile, and similar configurations arise independently across divergent lineages. In plants and animals, we modelled centromere evolution as a recurrent cycle, in which satellite- and transposon-based architectures interconvert, with independent origins of holocentricity. We curated >23 million satellite repeats comprising 263 families from 165 species. Despite sequence divergence between satellite families, higher order repeats are prevalent, indicating constraint on repeat architecture rather than primary sequence. Satellite arrays are heavily invaded by diverse transposon families, consistent with convergent adaptation to the centromeric niche. In 89 species, transposons themselves constitute the primary centromere structure. We observed centrophilic transposons forming tandem arrays, suggesting mechanisms for satellite regeneration. Our sample includes five independent origins of holocentricity in plants and animals, which vary in association with periodic satellite arrays. We propose that genetic instability, centrophilic transposition, and transmission distortion promote recurrent centromere architectural interconversions during evolution.

genomics↗

bioRxiv2026

Electron microscopy reveals water networks inside hydrated cellulose fibers

Cellulose is a highly abundant linear glucose polymer that exists in amorphous and fibrillar forms1-3. Primarily produced by vascular plants but also microbes and tunicates, cellulose predominantly performs architectural functions by stabilizing cell walls, tissues, and multicellular communities4-9. Owing to its association with other cell surface materials, physiological higher-order structures of cellulose have been difficult to obtain. Here, we describe a never-dried tunicate cellulose fibril structure by cryogenic electron microscopy, which resolves a fiber of more than 360 cellulose strands. Our data reveals linear and severely twisted fiber segments that are interspersed with solvent channels. Solid-state NMR analyses and molecular dynamics simulations indicate the presence of structural water molecules that form a network connecting neighboring cellulose chains. Confocal and super-resolution MINFLUX fluorescence imaging using cellulose-specific probes as well as biochemical analyses demonstrate shared surface and material properties of plant and tunicate cellulose fibers. Combined, our data suggest that architectural water molecules may be common features of cellulose fibers and likely other polysaccharide assemblies in their hydrated physiological states.

molecular biology↗

bioRxiv2026

Counterions, Polarization and Pore Hydration Relay Drive Ion Permeation through Hydrophobic Pore Formed by the MERS Coronavirus E Protein

Hydrophobic pores are generally expected to exclude ions because the large desolvation penalty associated with ion transfer cannot be compensated within a nonpolar environment. The envelope (E) protein of Middle East Respiratory Syndrome coronavirus (MERS-CoV) presents a striking exception, conducting cations with high efficiency despite forming a predominantly hydrophobic pore. To resolve this apparent paradox, we combine finite-temperature string simulations with additive and polarizable force fields to determine the minimum free-energy pathways for ion permeation through the MERS E channel. The simulations reveal a cooperative permeation mechanism in which transient counterion association, localized pore hydration, and electronic polarization jointly reduce the desolvation penalty. Rather than acting as passive spectators, counterions transiently chaperone the permeating cation before dissociating within the channel, thereby lowering the energetic cost of charge desolvation while preserving net ionic conductance. Explicit electronic polarization further reshapes the pore hydration landscape and cation-{pi} interactions, leading to substantially reduced free-energy barriers and a permeation mechanism in substantially better agreement with experiment. These results suggest that efficient ion transport through hydrophobic pores arises from the cooperative interplay between electrostatics, polarization and hydration rather than complete pore wetting, providing both a mechanistic framework for MERS E protein function and a general physical principle for ion transport through biological and synthetic hydrophobic nanopores.

biophysics↗

bioRxiv2026

Early Life Adversity Produces Enduring Molecular and Functional Disruption of Developing Vagal Circuits

Early life adversity (ELA) is a leading preventable contributor to morbidity and mortality, increasing risk for mental and physical illness later in life. However, mechanisms linking ELA to comorbid outcomes within both the brain and body remain poorly understood. We tested whether ELA disrupts functional and molecular development of vagal circuitry, a key pathway for brain-body communication, using the limited bedding and nesting (LBN) mouse model of unpredictable maternal care. We measured vagally mediated autonomic stress responses longitudinally using three noninvasive measures of heart rate variability (HRV). This is the first time the development of the vagally-mediated autonomic stress response has been measured in mice. We also performed single-nucleus RNA sequencing of the vagal medulla immediately after LBN and in adulthood, followed by spatial mapping of high-confidence differentially expressed genes. ELA altered trajectories of all HRV measures, with pronounced sex differences. ELA females showed precocious maturation followed by adult declines, whereas males initially exhibited blunted responses but recovered to control levels. Transcriptomic changes were also sex dependent, with female neurons exhibiting signatures of mitochondrial dysfunction, while males showed adaptive mitochondrial responses. Spatial mapping revealed rostro-caudal organization, localizing adaptive male responses to the rostral and intermediate vagal medulla and maladaptive female responses to the intermediate vagal medulla and loose nucleus ambiguus. These findings demonstrate enduring, sex-specific alterations in vagal circuit development centered on mitochondrial pathways.

neuroscience↗

bioRxiv2026

Simple Electroporation of Chlamydomonas reinhardtii Strains with an Intact Cell Wall

Chlamydomonas reinhardtii is a model green alga extensively used to study photosynthesis and cilia using molecular biology and genetics. Electroporation is a very common technique to transform DNA into the nuclear genome, which is essential to generate mutant collections and express transgenes. Here, we describe a simple, fast, and efficient protocol to transform strains with an intact cell wall. It achieves a good transformation efficiency without cell wall digestion or use of commercial kits and is compatible with the widely available Gene Pulser electroporation system. Key featuresO_LIHigh transformation efficiency of Chlamydomonas reinhardtii strains with an intact cell wall. C_LIO_LIFaster than currently available electroporation protocols. C_LI

molecular biology↗

bioRxiv2026

Identification of a somatic H3K23me3 methyltransferase SET-19 in C. elegans

Histone methylation plays essential roles in modulating chromatin organization and gene expression. H3K23 methylation is a conserved histone modification, yet its biological roles and the enzymes responsible for its deposition remain poorly understood. Here, we show that the loss of set-19 leads to a pronounced reduction in H3K23 methylation in C. elegans, as revealed by quantitative mass spectrometry, western blotting, and immunofluorescence staining. In vitro biochemical assays show that recombinant SET-19 proteins purified from E. coli directly catalyze H3K23 methylation. Genome-wide chromatin immunoprecipitation assays reveal that H3K23me3 is enriched at heterochromatic regions and that loss of set-19 alters H3K23me3 levels, accompanied by derepression of gene expression. Genetic analyses indicate that SET-19 is dispensable for both germline and somatic RNAi as well as transgenerational epigenetic inheritance of RNAi. SET-19 is predominantly expressed in somatic cells and specifically mediates H3K23me3 deposition in somatic tissues. The loss of set-19 causes a developmental delay without affecting fertility. Together, our results identify SET-19 as a somatic H3K23 methyltransferase and link H3K23me3 to gene repression in C. elegans.

genetics↗

bioRxiv2025

Precision at Every Scale: Efficiency in AI-Driven De Novo Antibody Design

The precise de novo design of antibodies remains a therapeutic challenge. The AI platform, GaluxDesign, was evaluated in a high-efficiency Precision-Scale Workflow by synthesizing and testing only 50 full-length IgG candidates per epitope across eight distinct epitopes from six therapeutic targets. This campaign yielded a 10.5% binder rate (estimated EC50 < 100 nM), identifying target-specific binders for seven of eight epitopes, with multiple candidates exhibiting sub-nanomolar to single-digit nanomolar dissociation constants (Kd). We further assessed the same workflow on nine shared benchmark targets selected for external comparison, where GaluxDesign identified target-specific binders for eight of nine targets, demonstrating strong target-level performance relative to previously reported de novo antibody design approaches. Together, these results establish a high-efficiency, precision-scale workflow for generating novel, high-affinity therapeutic antibodies.

bioengineering↗

bioRxiv2025

Transforming Hyperspectral Data into Insight: The DREAM Approach for Pathology

Quantitative pathology remains limited due to the need for chemical staining and subjective interpretation of tissue features. Autofluorescence imaging offers a label-free alternative: however, high-dimensional excitation-emission datasets pose challenges for visualization and reproducible analysis. Here, we present Dimensionality Reduction for Enhanced Autofluorescence Microscopy (DREAM), a method that condenses multi-excitation emission spectra into a compact, information-rich format using phasor-based tools. Applied to unstained esophageal tissue samples, DREAM enables high-contrast visualizations that distinguish key histological structures without the need for exogenous labeling. Quantitative assessments across multiple datasets show DREAM improves colorfulness, sharpness, and consistency over single-laser acquisitions, supporting its potential to advance objective, label-free diagnostics through enhanced spectral visualization.

biophysics↗

bioRxiv2025

Self-Reactive B Cells in Artery Tertiary Lymphoid Organs Encode Pathogenic High Affinity Autoantibody in Atherosclerosis

Artery tertiary lymphoid organs (ATLOs) emerge in atherosclerosis which is a chronic inflammatory artery disease with an autoimmune component. However, whether disease-relevant autoimmune B cells emerge in ATLOs and their impacts remains unknown. To map atherosclerosis-specific humoral autoimmunity and define its roles, we isolated germinal-center (GC) B cells from ATLOs and lymph-nodes, expression-cloned 60 autoantibodies and screened them for arterial wall reactivity. ATLO-derived autoantibodies markedly skewed to atherosclerosis-relevant autoantigens versus those of lymph-nodes. One ATLO GC-derived autoantibody bound to histone 2B (H2B) with high-affinity ([~]25 nM). Moreover, vaccination with H2B or adoptive transfer of its cognate autoantibody markedly accelerated atherosclerosis suggesting that ATLOs fail to delete pathogenic high-affinity self-reactive B cells. In a human cohort, total circulating anti H2B antibody titers positively correlated with aortic and coronary artery calcification. We conclude that ATLOs harbor a dysregulated immune tolerance environment permissive for autoreactive B cells that express pathogenic autoantibodies driving atherosclerosis.

immunology↗

bioRxiv2025

15-PGDH inhibition promotes hematopoietic recovery and enhances HSC function during aging

Hematopoietic aging is characterized by diminished stem cell regenerative capacity and an increased risk of hematologic dysfunction. We previously identified that the prostaglandin-degrading enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH) regulates hematopoietic stem cell activity. Here, we expand on this work and demonstrate that in aged mice, (1) 15-PGDH expression and activity remain conserved in the bone marrow and spleen, suggesting it remains a viable therapeutic target in aging, (2) prolonged PGDH inhibition (PGDHi) significantly increases the frequency and number of phenotypic hematopoietic stem and progenitor cells across multiple compartments, with transcriptional changes indicative of enhanced function, (3) PGDHi-treated bone marrow enhances short-term hematopoietic recovery following transplantation, leading to improved peripheral blood output and accelerated multilineage reconstitution, and (4) PGDHi confers a competitive advantage in primary hematopoietic transplantation while mitigating age-associated myeloid bias in secondary transplants. Notably, these effects occur without perturbing steady-state blood production, suggesting that PGDHi enhances hematopoiesis under regenerative conditions while maintaining homeostasis. Our work identifies PGDHi as a translatable intervention to rejuvenate aged HSCs and mitigate hematopoietic decline. Significance StatementWe identify 15-hydroxyprostaglandin dehydrogenase inhibition (PGDHi) as a strategy to enhance hematopoietic stem cell function in aging. In aged mice, PGDHi expands stem and progenitor populations, accelerates hematopoietic recovery after transplantation, and reduces myeloid bias while maintaining steady-state blood production. These findings highlight a potential therapeutic approach to restore hematopoietic resilience and improve regenerative outcomes in aging. Graphical Abstract15-prostaglandin dehydrogenase inhibition ameliorates multiple facets of age-related hematopoietic decline. Schematic made using BioRender.com. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=114 SRC="FIGDIR/small/648417v1_ufig1.gif" ALT="Figure 1"> View larger version (18K): org.highwire.dtl.DTLVardef@1952ad9org.highwire.dtl.DTLVardef@30169aorg.highwire.dtl.DTLVardef@11bec0corg.highwire.dtl.DTLVardef@2617c8_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2025

The H3K27me3 reader UAD-2 recruits a TAF-12-containing transcription condensates to initiate piRNA expression within heterochromatic clusters

Metazoans utilize the small RNA pathway to regulate gene expression and maintain genome integrity. This pathway directs histone H3 lysine 9 tri-methylation (H3K9me3) or histone H3 lysine 27 tri-methylation (H3K27me3) at target loci to induce transcriptional gene silencing. Interestingly, some small RNAs are generated from genomic loci enriched in H3K9me3 or H3K27me3. However, the transcription mechanism of small RNA precursors from these heterochromatic regions remains unclear. In C. elegans, piRNAs originate from two genomic clusters enriched with H3K27me3 marks, which recruit the H3K27me3 reader UAD-2 and the upstream sequence transcription complex (USTC). Here, we demonstrate that piRNA transcription in C. elegans relies on TAF-12, a subunit of the basal transcription factor IID (TFIID). Depletion of TAF-12 reduces the production of both piRNA precursors and mature piRNAs. TAF-12 interacts with UAD-2 and facilitates piRNA focus formation in germ cell nuclei. We further show that TAF-12 triggers piRNA transcription by recruiting the RNA polymerase II subunit RPB-5, the Mediator complex subunit MDT-8, and the general transcription factors GTF-2F2 and GTF-2H2C. Thus, piRNA transcription within heterochromatic regions depends on the collaboration between histone modification readers, piRNA-specific transcription factors, and core transcription machinery.

genetics↗

bioRxiv2025

Multidimensional characterization of cellular ecosystems in Hodgkin lymphoma

The tissue architecture of classic Hodgkin Lymphoma (CHL) is unique among cancers and characterized by rare malignant Hodgkin and Reed-Sternberg cells that co-evolve with a complex ecosystem of immune cells in the tumor microenvironment (TME). The lack of a comprehensive systems-level interrogation has hindered the description of disease heterogeneity and clinically relevant molecular subtypes. Here, we employed an integrative, multimodal approach to characterize CHL tumors using malignant cell sequencing, spatial transcriptomics and imaging mass cytometry. We identified four molecular subtypes (CST, CN913, STB, and CN2P), each characterized by distinct clinical features, mutational patterns, malignant cell gene expression profiles, and spatial architecture involving immune cell populations. Functional modeling of CSF2RB mutations, a characteristic feature of the CST subtype, revealed dysregulated oncogenic signaling and unique TME crosstalk. These findings highlight the significance of multi-dimensional profiling in elucidating patterns of molecular alterations that drive immune ecosystems and underlie therapeutically exploitable vulnerabilities.

cancer biology↗

bioRxiv2025

Structural and Functional Insights into GGCX-FIX Interaction: Implications for Vitamin K-Dependent Bleeding Disorders

Gamma-carboxylation, catalyzed by {gamma}-glutamyl carboxylase (GGCX), is a critical post-translational modification essential for the biological activity of vitamin K-dependent proteins (VKDPs). Mutations in GGCX, depending on their specific location, result in vitamin K-dependent coagulation factor deficiency type 1 (VKCFD1), which encompasses a broad spectrum of clinical manifestations ranging from mild to severe, including bleeding disorders, osteoporosis, and vascular calcification. The limited knowledge of GGCXs structure and functional regions hinders our understanding of the consequences of GGCX mutations and the treatment for VKCFD1. This study aimed to identify key functional regions of GGCX and their interactions with VKDPs to better elucidate the molecular mechanisms underlying these diverse clinical symptoms. Using AlphaFold 3 and molecular dynamics simulations, we developed a complex binding model of GGCX, FIX, and reduced vitamin K, which revealed critical regions and residues involved in their interaction. Site-directed mutagenesis and cell-based assays further validated the model, confirming that multisite and regional cooperative binding of FIX to GGCX plays a key role in modulating {gamma}-carboxylation efficiency. Additionally, novel residues (I296, M303, M401, M402) were identified as essential for GGCXs dual enzymatic activities: carboxylation and vitamin K epoxidation. We further demonstrated that the spatial proximity of these active sites supports the hypothesis that GGCXs carboxylation and vitamin K epoxidation centers are interconnected, ensuring the efficient coupling of these processes. Our GGCX-FIX binding and carboxylation model aligns with known pathogenic GGCX mutations, providing valuable insights into the molecular basis of coagulation disorders caused by GGCX mutants.

pathology↗

bioRxiv2024

Engineered mitochondrial A-to-G editors with enhanced efficiency and targeting scope

Mitochondrial base editing is a powerful technology, but the current A-to-G mitochondrial DNA (mtDNA) base editors are reluctant to achieve high efficiency, which is critical for mtDNA engineering. Through laboratory evolution, TadA-8e variants were discovered with substantially increased activity and expanded targeting compatibility, especially for previously unfavorite sequence contexts, when applied to both nuclear and mitochondrial ABEs. Further engineering of the mtDNA editors (eTd-mtABEs) dramatically reduced both DNA and RNA off-targeting effects and enhanced strand-selective A-to-G editing with substitution of DddA to DNA nickases. Moreover, the eTd-mtABEs induced up to 145-fold editing frequencies compared to previous mtDNA adenine base editors in rat cells, and installed targeted mutations in all injected rat embryos with up to 74% efficiency in founders, resulting generation of SNHL and Leigh syndrome models with severe defects. It suggests that eTd-mtABEs are promising mtDNA engineering technology for basic research and for translational studies. HighlightsO_LIEngineered TadA variants enhance nuclear and mitochondrial ABE activity in all sequence contexts. C_LIO_LIAdditional mutations in eTd-mtABEs further minimize both DNA and RNA off-targeting effects. C_LIO_LIEngineered TadA variants are compatible to DNA nickase assisted strand-selective mtDNA editing. C_LIO_LIeTd-mtABEs enable highly efficient generation of rat mtDNA disease models with severe phenotypes. C_LI

bioengineering↗

bioRxiv2024

Shared Transcriptomic Signatures Reveal Synaptic Pruning as a Link Between Alzheimer's Disease and Epilepsy

Alzheimers disease (AD) and epilepsy (EP) share a complex bidirectional relationship, yet the molecular mechanisms underlying their comorbidity remain insufficiently explored. To identify potential transcriptional programs across animal models and human patients with AD and EP, we conducted a comprehensive genome-wide transcriptomic analysis. Our investigation included mouse models of temporal lobe epilepsy (pilocarpine- and kainic acid-induced; n = 280), AD transgenic models (7 transgenic models expressing human tau or amyloid pathology; n = 257), and performed cross-species validation in human cohorts (EP: n = 182; AD: n = 301). We identified a highly conserved immune-related module across all models and patient cohorts. The hub consensus signatures of this module were centered around a microglial synaptic pruning pathway involving TYROBP, TREM2, and C1Q complement components. Gene regulatory network analysis identified TYROBP as the key upstream hub signature. These signatures showed consistent up-regulation in both conditions and strong diagnostic potential. Differential expression analyses revealed their predominant expression in specific microglial subpopulations associated with complement-mediated synaptic pruning and immune activation. Neural circuit modeling further demonstrates the asymmetric sensitivity of synaptic pruning to network dynamics. Loss of inhibitory synapses has a disproportionately significant impact on neural network excitation/inhibition balance and synchronization. Our findings support microglial complement-mediated synaptic pruning as a conserved central pathway linking neurodegeneration to epileptogenesis, suggesting a promising therapeutic target for AD and EP comorbidity. Graphic abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=193 SRC="FIGDIR/small/618752v12_ufig1.gif" ALT="Figure 1"> View larger version (70K): org.highwire.dtl.DTLVardef@179aa28org.highwire.dtl.DTLVardef@922dfaorg.highwire.dtl.DTLVardef@108a99eorg.highwire.dtl.DTLVardef@1b7d2f6_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIGenome-wide transcriptomic analysis across epilepsy (EP) and Alzheimers disease (AD) models and patients identified a conserved immune module. C_LIO_LIThe TYROBP-TREM2-C1Q microglial synaptic pruning pathway was identified as a central consensus signature across model and patient cohorts. C_LIO_LIConsensus signatures possess potential diagnostic utility in AD and EP patients, with predominant expression in specific microglial subpopulations C_LIO_LINeural circuit modeling demonstrates the asymmetric effects of synaptic pruning, whereby loss of inhibitory synapses disproportionately disrupts the E/I balance, leading to increased network synchronization. C_LI

bioinformatics↗

bioRxiv2024

Benchmarking for the automated detection and classification of southern yellow-cheeked crested gibbon calls from passive acoustic monitoring data

Recent advances in deep and transfer learning have revolutionized our ability for the automated detection and classification of acoustic signals from long-term recordings. Here, we provide a benchmark for the automated detection of southern yellow-cheeked crested gibbon (Nomascus gabriellae) calls collected using autonomous recording units (ARUs) in Andoung Kraleung Village, Cambodia. We compared the performance of support vector machines (SVMs), a quasi-DenseNet architecture (Koogu), transfer learning with pretrained convolutional neural network (ResNet50) models trained on the ImageNet dataset, and transfer learning with embeddings from a global birdsong model (BirdNET) based on an EfficientNet architecture. We also investigated the impact of varying the number of training samples on the performance of these models. We found that BirdNET had superior performance with a smaller number of training samples, whereas Koogu and ResNet50 models only had acceptable performance with a larger number of training samples (>200 gibbon samples). Effective automated detection approaches are critical for monitoring endangered species, like gibbons. It is unclear how generalizable these results are for other signals, and future work on other vocal species will be informative. Code and data are publicly available for future benchmarking.

ecology↗

bioRxiv2024

Spiking neural network models of sound localisation via a massively collaborative process

AbstractNeuroscientists are increasingly initiating large-scale collaborations which bring together tens to hundreds of researchers. However, while these projects represent a step-change in scale, they retain a traditional structure with centralised funding, participating laboratories and data sharing on publication. Inspired by an open-source project in pure mathematics, we set out to test the feasibility of an alternative structure by running a grassroots, massively collaborative project in computational neuroscience. To do so, we launched a public Git repository, with code for training spiking neural networks to solve a sound localisation task via surrogate gradient descent. We then invited anyone, anywhere to use this code as a springboard for exploring questions of interest to them, and encouraged participants to share their work both asynchro-nously through Git and synchronously at monthly online workshops. At a scientific level, our work investigated how a range of biologically-relevant parameters, from time delays to mem-brane time constants and levels of inhibition, could impact sound localisation in networks of spiking units. At a more macro-level, our project brought together 31 researchers from multiple countries, provided hands-on research experience to early career participants, and opportunities for supervision and teaching to later career participants. Looking ahead, our project provides a glimpse of what open, collaborative science could look like and provides a necessary, tentative step towards it.

neuroscience↗

bioRxiv2024

GeneLLM: A Large cfRNA Language Model for Cancer Screening from Raw Reads

We present GeneLLM, a novel large language model that offers a transformative approach to non-invasive cancer detection and biomarker discovery by directly interpreting plasma cell-free RNA (cfRNA) sequences. Unlike traditional annotation-dependent methods, GeneLLM operates without prior knowledge, achieving significantly improved multi-cancer detection accuracy. Critically, GeneLLM identifies novel cfRNAs ( pseudo-biomarkers) originating from previously unannotated genomic regions-overlooked by existing methods-offering new therapeutic targets and insights into intercellular communication. This innovative, cost-effective approach bypasses traditional bioinformatics tools, generating novel pseudo-biomarkers that outperform existing methods even with low-depth sequencing data. Consequently, GeneLLM opens new avenues for biomarker discovery and expands our understanding of the extracellular transcriptomes role in cancer development.

bioinformatics↗