Biology subjects

Kim, H. J.

Publications and source records attributed to Kim, H. J..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

High-resolution single-cell RNA sequencing using canFam4 reveals novel immune subsets and checkpoint programs in healthy dogs

Single-cell RNA sequencing (scRNA-seq) enables high-resolution profiling of immune heterogeneity. Although previous studies have mapped the single-cell transcriptomic atlases of peripheral leukocytes in healthy dogs, the identification and functional characterization of distinct immune subsets remain incomplete. We constructed a single-cell atlas of peripheral leukocytes from six healthy small-breed dogs using the 10x Genomics platform and the updated canFam4 genome. Analysis of 30,040 high-quality transcriptomes revealed 51 distinct immune subsets, including CD14{square}CD33{square} monocytes, XCR1{square}CD1D{square} dendritic cells, CEACAM1{square}CD24{square} neutrophils, and IL32{square}BATF{square} regulatory T cells, which were underrepresented in canFam3.1-based studies. Interferon-enriched CD14{square} monocytes and CD4{square} T subsets associated with myxomatous mitral valve disease were also identified. Functional analysis revealed that PDCD1 attenuates TCR signaling, LAG3 modulates malate metabolism in CD4{square} T cells, and suppresses TBX21 in CD8{square} T cells associated with viral response. CD274 encoding PD-L1 was linked to IL-10 production in neutrophils, and CTLA4 represented an initial activation of double-negative T subsets. T cell exhaustion scores and proliferative fractions varied across cohorts, reflecting differences in environmental antigenic exposures. Our study represents the first comprehensive, gene-resolved single-cell analysis that reveals immunoregulatory checkpoint mechanisms underlying immune homeostasis in healthy dogs. Our dataset will serve as a valuable resource for future comparative and translational immunology research in dogs.

immunology↗

bioRxiv2025

Probiotic Intervention Mitigates Radiation-Induced Intestinal Injury by Alleviating Oxidative Stress in a Human Gut-on-a-chip

Gastrointestinal acute radiation syndrome (GI-ARS) poses a critical public health concern, necessitating the development of effective medical countermeasures (MCM). Here, we evaluated the therapeutic potential of a commercially available probiotic formulation using human gut-on-a-chip model that mimics physiodynamic intestinal microenvironment. Intestinal epithelial Caco-2 cells were subjected to 8 Gray gamma radiation, targeting the epithelial layer, the culture medium, or both. The irradiated epithelial cells challenged to the irradiated medium resulted in significant DNA damage quantified by the presence of 53BP1 foci, increased cellular injury, and disrupted epithelial morphology. While epithelial irradiation alone did not compromise structural integrity, longitudinal exposure to irradiated medium induced oxidative stress, leading to morphological damage. Administration of the probiotic formulation significantly suppressed reactive oxygen species production, reduced epithelial damage, and preserved microarchitecture, independent of direct modulation of DNA damage. These findings suggest that probiotics may serve as promising live biotherapeutic MCM for mitigating GI-ARS in high-risk radiological exposures.

bioengineering↗

bioRxiv2025

Refate identifies chemical compounds to target trans-regulatory networks for cellular conversion

Identifying chemical compounds that target trans-regulatory networks (TRNs) underlying molecular programs of cells for directed cellular conversion (i.e. differentiation, reprogramming, transdifferentiation, and dedifferentiation) is a key step towards advancing regenerative medicine. Recent innovations in single-cell omics technologies enabled high-resolution profiling of TRNs that govern cell identity and cell-fate decisions. Here, we introduce Refate, a computational framework that integrates large-scale multimodal single-cell atlas data to quantify cell propensity of genes, together with six drug databases, to identify chemical compounds that target TRNs for directed cellular conversion. The reconstructed TRNs, including protein-protein interactions and gene regulatory networks, alongside chemical compounds that drive the cellular conversion provide greater biological interpretability and improve efficiency and efficacy. We evaluated Refate by testing its ability to uncover known transcription factors and chemical compounds validated in experimental conversions of various cell types. Furthermore, we experimentally validated the attribute of several novel chemical compounds identified by Refate for enhancing the conversion of human embryonic stem cells to human cranial neural crest cells. Together, these findings demonstrate Refate as an effective tool for discovering chemical compounds that target TRNs to enable cellular conversion, advancing efforts towards regenerative medicine. HighlightsO_LIRefate quantifies genes for cellular conversion using multimodal single-cell atlases C_LIO_LIRefate uncovers trans-regulatory networks (TRNs) underlying cellular conversion C_LIO_LIRefate identifies chemical compounds that target TRNs for cellular conversion C_LIO_LIValidation of Refate identified chemical compounds for hESC to hCNCC conversion C_LI

developmental biology↗

bioRxiv2025

X-Atlas/Orion: Genome-wide Perturb-seq Datasets via a Scalable Fix-Cryopreserve Platform for Training Dose-Dependent Biological Foundation Models

The rapid expansion of massively parallel sequencing technologies has enabled the development of foundation models to uncover novel biological findings. While these have the potential to significantly accelerate scientific discoveries by creating AI-driven virtual cell models, their progress has been greatly limited by the lack of large-scale high-quality perturbation data, which remains constrained due to scalability bottlenecks and assay variability. Here, we introduce "Fix-Cryopreserve-ScRNAseq" (FiCS) Perturb-seq, an industrialized platform for scalable Perturb-seq data generation. We demonstrate that FiCS Perturb-seq exhibits high sensitivity and low batch effects, effectively capturing perturbation-induced transcriptomic changes and recapitulating known biological pathways and protein complexes. In addition, we release X-Atlas: Orion edition (X-Atlas/Orion), the largest publicly available Perturb-seq atlas. This atlas, generated from two genome-wide FiCS Perturb-seq experiments targeting all human protein-coding genes, comprises eight million cells deeply sequenced to over 16,000 unique molecular identifiers (UMIs) per cell. Furthermore, we show that single guide RNA (sgRNA) abundance can serve as a proxy for gene knockdown (KD) efficacy. Leveraging the deep sequencing and substantial cell numbers per perturbation, we also show that stratification by sgRNA expression can reveal dose-dependent genetic effects. Taken together, we demonstrate that FiCS Perturb-seq is an efficient and scalable platform for high-throughput Perturb-seq screens. Through the release of X-Atlas/Orion, we highlight the potential of FiCS Perturb-seq to address current scalability and variability challenges in data generation, advance foundation model development that incorporates gene-dosage effects, and accelerate biological discoveries.

genomics↗

bioRxiv2025

Mechanostimulatory cues determine intestinal fibroblast fate and profibrotic remodeling in a physiodynamic human gut-on-a-chip

Biomechanical cues, including shear stress and mechanical strain, are key regulators of intestinal cellular behavior, yet their mechanostimulatory impact on fibroblasts responses during early fibrotic remodeling remains poorly understood. Using a bioengineered gut-on-a-chip model, we independently modulated flow and mechanical strain to assess fibroblast dynamics under intact or impaired epithelial barriers. Inflammation-associated fibroblasts resisted biomechanical stress, exhibiting myofibroblast-like phenotypes with hypertrophy and elevated -smooth muscle actin aligned with stress fibers. In contrast, normal fibroblasts were highly susceptible to shear stress, undergoing matrix metalloproteinase-dependent apoptotic injury, while mechanical strain alone had minimal effect. Notably, an intact epithelial barrier was both necessary and sufficient to protect fibroblasts from shear-induced damage, suggesting that "good fences make good neighbors". Under barrier dysfunction, prolonged exposure to shear stress induced the formation of stiff fibroblast aggregates composed of mechanoadaptive myofibroblast-like cells. These findings identify mechanostimulatory cues, particularly shear stress, as critical drivers of early fibrotic remodeling in inflammatory bowel disease and underscore epithelial barrier integrity as an essential biomechanical safeguard against pathological fibroblast dysregulation.

bioengineering↗

bioRxiv2025

Characterization of Human Anterior Neural Organoids as a Model for Investigating Cohen Syndrome

Neural organoids display three-dimensional (3D) structures that resemble in vivo neural architectures. Previously, we developed a novel two-dimensional (2D) neural induction-based protocol for culturing spinal cord organoids, enabling size control and recapitulating neural tube morphogenesis. In this study, we evaluated the application of this concept to induce the anterior regions of the brain and generate human anterior neural organoids (hANOs). By inducing neuroepithelial (NE) cells in 2D and re-aggregating them led to tube-forming morphogenesis similar to that posterior spinal cord induction. The transcriptome profiles of these hANOs resembled the frontal cortex of 20 weeks post-conception (PCW) human embryos. Using this hANOs protocol, we investigated microcephaly phenotypes associated with Cohen syndrome (CS), caused by biallelic loss-of-function variants in VPS13B gene. Deleting VPS13B in human pluripotent stem cells resulted in Golgi dispersion and growth retardation onset in mutant hANOs, akin to CS patients with postnatal microcephaly. This delay is partly linked to reduced neuronal growth. Additionally, mature CS organoids showed enhanced hyper-excitability associated with an excitatory/inhibitory imbalance. In conclusion, this protocol is suitable for studying microcephaly phenotypes from human genetic mutations due to its simplicity and scalability.

neuroscience↗

bioRxiv2025

RNF13 mediates pH- and Ca2+-dependent regulation of lysosomal positioning

Environmental factors such as extracellular pH (pHe) and nutritional status influence lysosomal localization and autophagy. However, the mechanisms by which pHe, intracellular pH (pHi), and Ca2+ levels coordinate the bidirectional transport of lysosomes remain poorly understood. In this study, we identify RNF13 as a critical regulator of lysosomal positioning through its ubiquitin- dependent degradation of ARL8B. RNF13 activity is modulated by both pHi and Ca2+ levels. Specifically, we demonstrate that Ca2+-activated apoptosis-linked gene 2 (ALG-2) promotes retrograde lysosomal transport while simultaneously increasing pHi and decreasing lysosomal pH (pHlys). Elevated pHi deprotonates RNF13 at His332, enabling its interaction with Ca2+-bound ALG-2. This interaction activates RNF13, which inhibits ARL8B-mediated anterograde lysosomal transport. Furthermore, we show that alkaline pHe elevates pHlys, activating the lysosomal Ca2+ channel TRPML3. This activation enhances RNF13 activity, driving lysosomes to adopt a perinuclear localization. Thus, conditions such as starvation or alkaline pHe, which induce ALG-2 activation and pHi elevation, facilitate RNF13- mediated ARL8B degradation. In contrast, under acidic pHi conditions, RNF13 activity remains suppressed regardless of ALG-2 activation, leading to increased ARL8B levels. Additionally, we provide evidence linking the loss of RNF13 activity to developmental and epileptic encephalopathy-73, a neurological disorder characterized by severe developmental symptoms. These findings deepen our understanding of lysosomal positioning mechanisms, highlighting the interplay between lysosomal Ca2+ release and dynamic changes in cytoplasmic and lysosomal pH.

cell biology↗

bioRxiv2025

Combinatorial effects of Zingiber officinale and Citrus limon juices: Hypolipidemic and antioxidant insights from in vivo, in vitro, and in silico investigations

The combined use of Zingiber officinale (ginger) and Citrus limon (lemon) has long been valued in traditional medicine for their significant therapeutic properties, particularly in supporting cardiovascular health. However, their synergistic effects on hyperlipidemia and oxidative stress, both critical risk factors for cardiovascular diseases, remain underexplored. This study employed a multidisciplinary approach including in vivo (mice model with triton WR-1339-induced hyperlipidemia), in vitro (antioxidant assays such as DPPH and ABTS), and in silico (molecular docking targeting HMG-CoA reductase) to evaluate the hypolipidemic and antioxidant potential of ginger and lemon juices. Phytochemical analysis identified high concentrations of bioactive compounds, with ginger juice containing 6-gingerol (15.54% peak area) and lemon juice featuring hesperidin (13.85% peak area) and rutin (5.57% peak area). These compounds were instrumental in the observed pharmacological effects. The combined formulation significantly improved lipid profiles, reducing total cholesterol by 54.3%, triglycerides by 49.8%, and LDL by 58.1% while increasing HDL by 47.6% compared to hyperlipidemic controls (p < 0.05). Antioxidant assays revealed high free radical scavenging activity, with IC50 values of 30.92 {+/-} 2.00 {micro}g/mL for ABTS and 44.94 {+/-} 1.02 {micro}g/mL for DPPH in the combined formulation. Molecular docking confirmed strong binding affinities, with hesperidin and 6-gingerol showing binding energies of -10.4 kcal/mol and -9.6 kcal/mol, respectively, against HMG-CoA reductase. In conclusion, combining Zingiber officinale and Citrus limon juices demonstrates robust hypolipidemic and antioxidant effects, significantly outperforming the individual juices. These results support their potential as natural therapeutic agents for managing hyperlipidemia and oxidative stress. Further clinical studies are recommended to validate these promising findings and explore their application in nutraceutical development.

pharmacology and toxicology↗

bioRxiv2024

Bone marrow microenvironment signatures associate with patient survival after guadecitabine and atezolizumab therapy in HMA-resistant MDS

Almost 50% of patients with myelodysplastic syndrome (MDS) are refractory to first-line hypomethylating agents (HMAs), which presents a significant clinical challenge considering the lack of options for salvage. Past work revealed that immune checkpoint molecules on peripheral myeloblasts and immune cells are up-regulated after HMA treatment. Therefore, we conducted a Phase I/II clinical trial combining guadecitabine (an HMA) and atezolizumab (an immune checkpoint inhibitor) to treat HMA-relapsed or refractory (HMA-R/R) MDS patients. This combination therapy showed median overall survival of 15.1 months relative to historical controls (4-6 months). Here, we profiled the cell composition and gene expression signatures of cells from bone marrow aspirates from trial participants with short-term (<15 months) or long-term (>15 months) survival at single-cell resolution. Long-term survivors showed a significant reduction of immunosuppressive monocytes, and an expansion of effector lymphocytes after combination therapy. Further immune profiling suggests that gamma delta T cell activation through primed dendritic cells was associated with global interferon activation in the bone marrow microenvironment of long-term survivors. Short-term survivors exhibited elevated inflammation and senescence-like gene signatures that were not resolved by combination therapy. We propose that distinct bone marrow microenvironment features, such as senescence-associated inflammation or immunosuppressive monocyte presence, could improve patient stratification for HMA and immunotherapy combinations in HMA-R/R MDS patients.

cancer biology↗

bioRxiv2024

IDH-mutant gliomas arise from glial progenitor cells harboring the initial driver mutation

Discovering the cell-of-origin harboring the initial driver mutation provides a fundamental basis for understanding tumor evolution and development of new treatments. For isocitrate dehydrogenase (IDH)-mutant gliomas - the most common malignant primary brain tumors in adults under 50 - the cell-of-origin remains poorly understood. Here, using patient brain tissues and genome-edited mice, we identified glial progenitor cells (GPCs), including oligodendrocyte progenitor cells (OPCs), as the glioma-originating cell type harboring the IDH mutation as the initial driver mutation. We conducted comprehensive deep sequencing, including droplet digital PCR and deep panel and amplicon sequencing to 128 tissues from 62 patients (29 IDH-mutant gliomas and 33 IDH-negative controls) comprising tumors, normal cortex or normal subventricular zone (SVZ), and blood. Surprisingly, low-level IDH mutation was found in the normal cortex away from the tumor in 38.5% (10 of 26) of IDH-mutant glioma patients, whereas no IDH mutation was detected in the normal SVZ. Furthermore, by analyzing cell-type-specific mutations, the direction of clonal evolution, the single-cell transcriptome from patient brains and novel mouse model of IDH-mutant glioma arising from mutation-carrying OPCs, we determined that GPCs, including OPCs, harboring the initial driver mutation are responsible for the development and evolution of IDH-mutant gliomas. In summary, our results demonstrate that GPCs containing the IDH mutation are the cells-of-origin harboring the initial driver mutation in IDH-mutant gliomas.

cancer biology↗

bioRxiv2024

Structural Insights into the Role of the Proline Rich Region in Tau Function

Tau is a microtubule-associated protein that plays an important role in modulating axonal microtubules in neurons. Intracellular tau aggregates are found in a broad class of disorders, including Alzheimers disease, termed tauopathies. Tau is an intrinsically disordered protein, and its structural disorder appears to be critical to its microtubule-related functions. Tubulin binding sites are found in taus proline-rich region (PRR), microtubule binding repeats (MTBR: R1-R4), and pseudo-repeat, R'. While many post-translational modifications have been identified on tau, phosphorylation sites, which both regulate tubulin dimer and microtubule interactions and are correlated with disease, cluster with high frequency within the PRR. Here, we use fluorescence correlation spectroscopy and structural mass spectrometry techniques to characterize the impact of phosphomimic mutations in the PRR on tubulin dimer binding and probe the structure of the PRR-tubulin dimer complex. We find that phosphomimics cumulatively diminish tubulin dimer binding and slow microtubule polymerization. Additionally, we map two [~]15 residue regions of the PRR as primary tubulin dimer binding sites and propose a model in which PRR enhances lateral interactions between tubulin dimers, complementing the longitudinal interactions observed for MTBR. Together these measurements provide insight into the previously overlooked relevance of taus PRR in functional interactions with tubulin. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=181 SRC="FIGDIR/small/614010v1_ufig1.gif" ALT="Figure 1"> View larger version (49K): org.highwire.dtl.DTLVardef@360dd3org.highwire.dtl.DTLVardef@c5d75aorg.highwire.dtl.DTLVardef@bd76eeorg.highwire.dtl.DTLVardef@cb433c_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗

bioRxiv2024

Systematic evaluation of blastoid models of early human development

Recent generation of stem cell-derived blastoids that recapitulate the architecture and cellular constitution of the human blastocyst offers an experimental model for the elucidation of the biology of early human development. To evaluate the fidelity of the blastoids for modelling human blastocysts, we first established a reference map of cell identity and lineage differentiation of the human blastocysts through the integration and curation of single-cell transcriptome data of ex vivo blastocysts profiled at a range of developmental timepoints in culture. We next use this reference map to assess the coverage and the authenticity of cell lineages and the progression of lineage differentiation of various blastoid models generated with different cellular sources and protocols. This reference map generated from this study enables the benchmarking of blastoids that may guide the optimization of the protocol for the generation of high-fidelity blastoid models that faithfully recapitulate the natural human blastocyst.

systems biology↗

bioRxiv2024

Structural basis of the human transcriptional Mediator complex modulated by its dissociable Kinase module

The eukaryotic Mediator, comprising a large Core (cMED) and a dissociable CDK8 kinase module (CKM), regulates RNA Polymerase II (Pol II)-dependent transcription. cMED recruits Pol II and promotes pre-initiation complex (PIC) formation in a manner inhibited by the CKM, which is also implicated in post-initiation control of gene expression. Herein we report cryo-electron microscopy structures of the human complete Mediator and its CKM, which explains the basis for CKM inhibition of cMED-activated transcription. The CKM binds to cMED through an intrinsically disordered region (IDR) in MED13 and HEAT repeats in MED12. The CKM inhibits transcription by allocating its MED13 IDR to occlude binding of Pol II and MED26 to cMED and further obstructing cMED-PIC assembly through steric hindrance with TFIIH and the +1 nucleosome. Notably, MED12 binds to the cMED Hook, positioning CDK8 downstream of the transcription start site, which sheds new light on its stimulatory function in post-initiation events.

biochemistry↗

bioRxiv2024

GluN2B-mediated regulation of silent synapses for receptor specification and addiction memory

Psycho-stimulants including cocaine elicit stereotyped, addictive behaviors. Re-emergence of silent synapses containing only NMDA-type glutamate receptors (NMDARs) is a critical mediator of addiction memory and seeking behaviors. Despite the predominant abundance of GluN2B-containing NMDARs in silent synapses, their operational mechanisms are not fully understood. Using conditional depletion/deletion of GluN2B at D1-expressing accumbal medium spiny neurons, we examine the synaptic and behavioral actions that silent synapses incur after repeated exposure to cocaine. GluN2B ablation reduces the proportion of silent synapses, but some of them can persist by substitution to GluN2C, which drives the aberrantly-facilitated synaptic incorporation of calcium-impermeable AMPA-type glutamate receptors (AMPARs). The resultant precocious maturation of silent synapses impairs addiction memory but elevates locomotor activity, which can be normalized by blockade of calcium-impermeable AMPAR trafficking. Collectively, GluN2B supports the competence of cocaine-induced silent synapses for specifying subunit composition of AMPARs, and thereby expression of addition memory and the related behaviors.

neuroscience↗

bioRxiv2024

Determination of permissive and restraining cancer-associated fibroblast (DeCAF) subtypes

Cancer-associated fibroblast (CAF) subpopulations in pancreatic ductal adenocarcinoma (PDAC) have been identified using single-cell RNA sequencing (scRNAseq) with divergent characteristics, but their clinical relevance remains unclear. We translate scRNAseq-derived CAF cell-subpopulation-specific marker genes to bulk RNAseq data, and develop a single- sample classifier, DeCAF, for the classification of clinically restraining and permissive CAF subtypes. We validate DeCAF in 19 independent bulk transcriptomic datasets across four tumor types (PDAC, mesothelioma, bladder and renal cell carcinoma). DeCAF subtypes have distinct histology features, immune landscapes, and are prognostic and predict response to therapy across cancer types. We demonstrate that DeCAF is clinically replicable and robust for the classification of CAF subtypes in patients for multiple tumor types, providing a better framework for the future development and translation of therapies against permissive CAF subtypes and preservation of restraining CAF subtypes. SignificanceWe introduce a replicable and robust classifier, DeCAF, that delineates the significance of the role of permissive and restraining CAF subtypes in cancer patients. DeCAF is clinically tractable, prognostic and predictive of treatment response in multiple cancer types and lays the translational groundwork for the preclinical and clinical development of CAF subtype specific therapies.

genomics↗

bioRxiv2024

Characterization of the mesendoderm progenitors in the gastrulating mouse embryo

A population of putative mesendoderm progenitor cells that can contribute cellular descendants to both mesoderm and endoderm lineages is identified. These progenitor cells are localized to the anterior primitive streak and the adjacent epiblast of E7.0-E7.5 mid-to late-gastrula stage embryos. Lineage tracing in vivo revealed that putative mesendoderm progenitors that are marked by Mixl1 and Mesp1 activity contribute descendants to the endoderm layer. Analysis of the role of Mixl1 transcription factor in endoderm differentiation of the mouse epiblast stem cells revealed the choice for endoderm or mesoderm cell fate depends on the timing of activation of Mixl1 upon exit from pluripotency, suggesting Mixl1 function may underpin the divergence of the mesendoderm progenitor to mesoderm and endoderm lineages. The knowledge gained on the spatial, temporal, and lineage attribute of mesendoderm progenitors enriches our mechanistic understanding of germ layer allocation and endoderm differentiation of mesendoderm progenitor in embryonic development and lineage allocation of primed state pluripotent stem cells in vitro.

developmental biology↗

bioRxiv2024

An integrative single-cell atlas to explore the cellular and temporal specificity of neurological disorder genes during human brain development

Single-cell technologies have enhanced comprehensive knowledge regarding the human brain by facilitating an extensive transcriptomic census across diverse brain regions. Nevertheless, understanding the cellular and temporal specificity of neurological disorders remains ambiguous due to the developmental variations. To address this gap, we illustrated the dynamics of disorder risk gene expressions under development by integrating multiple single-cell RNA sequencing datasets. We constructed a comprehensive single-cell atlas of developing human brains, encompassing 393,060 single cells across diverse developmental stages. Temporal analysis revealed the distinct expression patterns of disorder risk genes, including autism, highlighting their temporal regulation in different neuronal and glial lineages. We identified distinct neuronal lineages diverged across developmental stages, each exhibiting temporal-specific expression patterns of disorder genes. Lineages of non-neuronal cells determined by molecular profiles also showed temporal-specific expressions, indicating a link between cellular maturation and the risk of disorder. Furthermore, we explored the regulatory mechanisms involved in early brain development, revealing enriched patterns of fetal cell types for neuronal disorders, indicative of the prenatal stages influence on disease determination. Our findings facilitate unbiased comparisons of cell type-disorder associations and provide insight into dynamic alterations in risk genes during development, paving the way for a deeper understanding of neurological disorders.

neuroscience↗

bioRxiv2024

Enterohemorrhagic Escherichia coli (EHEC) Disrupts Intestinal Barrier Integrity in Translational Canine Stem Cell-Derived Monolayers

This study addresses the gap in translatable in vitro models for investigating Enterohemorrhagic E. coli (EHEC) infections, particularly relevant to both canine and human health. EHEC is known to induce acute colitis in dogs, leading to symptoms like hemorrhagic diarrhea and hemolytic uremic syndrome, similar to those observed in humans. However, understanding the pathophysiology and developing treatment strategies have been challenging due to the lack of effective models that replicate the clinical disease caused by EHEC in both species. Our approach involved the development of colonoid-derived monolayers using intestinal tissues from healthy, client-owned dogs. These monolayers were exposed to EHEC and the impact of EHEC was assessed through several techniques, including trans-epithelial electrical resistance (TEER) measurement, immunofluorescence staining for junction proteins and mucus, and scanning electron microscopy for morphological analysis. Modified culture with saline, which was intended to prevent bacterial overgrowth, maintained barrier integrity and cell differentiation. EHEC infection led to significant decreases in TEER and ZO-1 expression, but not in E- cadherin levels or mucus production. Additionally, EHEC elicited a notable increase in TNF- production, highlighting its distinct impact on canine intestinal epithelial cells compared to non-pathogenic E. coli. These findings closely replicate in vivo observations in dogs and humans with EHEC enteropathy, validating the canine colonoid-derived monolayer system as a translational model to study host- pathogen interactions in EHEC and potentially other clinically significant enteric pathogens.

microbiology↗