Biology subjects

Kang, N.

Publications and source records attributed to Kang, N..

17 recordsLinked to original sources

bioRxiv2026

Towards a complete diploid chicken genome

The repetitive and heterochromatic parts of microchromosomes and dot chromosomes have impeded the creation of a complete, haplotype-resolved chicken genome. To overcome these challenges, we employed a trio-sequencing approach, utilizing long reads from a female chick, supplemented by parental long-read data for accurate haplotype phasing. This strategy produced nearly complete, haplotype-resolved paternal and maternal assemblies, with 14 residual gaps. Telomeric sequences remain missing in two paternal and four maternal chromosomes, suggesting a still incomplete assembly. GGswu2 resolved more than 50 Mb of previously unresolved regions, predominantly within dot chromosomes. The dot chromosomes exhibit low nucleotide diversity but a high density of structural variants between haplotypes. We found that the centromere sizes and relative positions of centromere cores sometimes differ between the two haplotype genomes. These findings suggest that comparative genomics must incorporate the high-resolution of these dynamic complex regions to fully understand avian genome evolution and genetic complexity.

genomics↗

bioRxiv2026

Single-cell profiling of physically interacting immune cells using image-guided sorting

Single-cell transcriptomics of cell-cell complexes offers key insights into in vivo immune interactions, yet distinguishing true physical contacts from artifacts remains challenging. Here, we integrated spectral imaging cell sorting with physical cell deconvolution to separate circulating T cell-monocyte doublets from tuberculosis patients into physically interacting (in-contact) and non-interacting (coincidental) populations. Single-cell sequencing of individual cell partners revealed that physical contact is associated with robust signatures distinct from singlets, including unidirectional monocyte-to-T cell RNA transfer, heightened metabolic activity and T cell cytotoxicity, and a trend toward antigen-specific enrichment. These signatures spanned all T cell and monocyte subpopulations, reflecting a global program of T cell-monocyte engagement. Coincidental doublets displayed intermediate transcriptional profiles between singlet and in-contact states, suggesting the presence of recently disrupted or forming physical pairs. This framework provides high-fidelity deconvolution of cellular interactions, uncovering signatures governing T cell-monocyte communication in human disease.

immunology↗

bioRxiv2026

Associations of age, sex, and bicuspid aortic valve with biaxial mechanical properties and circumferential residual stress in ascending thoracic aortic aneurysm

Background: Ascending thoracic aortic aneurysm (ATAA) is characterized by progressive biomechanical remodeling that is incompletely captured by maximum aortic diameter. The relationships between age, sex, aortic valve phenotype (BAV vs TAV), and aneurysmal mechanics remains incompletely understood. Methods: Ascending aortic specimens from 54 patients undergoing elective ATAA repair were evaluated. Biaxial testing quantified Green strain and local stiffness at membrane tensions of 60 and 120 N/m. Opening angle was used to assess circumferential residual stress and stretch. Associations with age were evaluated using Pearson correlations, and differences between sex and valve phenotype were also explored. Multivariable linear regression models including age, sex, and valve phenotype were used to evaluate their adjusted associations with each mechanical outcome. Results: Increasing age was associated with increased local stiffness and reduced Green strain and remained the strongest determinant of biaxial mechanical properties after adjustment. Compared with tricuspid aortic valve specimens, BAV specimens exhibited lower Green strain together with lower local stiffness. Females demonstrated greater Green strain in unadjusted analyses; however, after adjustment, sex remained associated only with longitudinal Green strain at 60 N/m. None of the evaluated clinical characteristics consistently explained opening angle or residual stretch. Conclusions: Age was the predominant clinical determinant of biaxial mechanical remodeling in ATAA, whereas valve phenotype demonstrated selective associations and sex contributed comparatively little after adjustment. Circumferential residual stress appeared largely independent of these clinical characteristics, suggesting that residual stress and biaxial mechanics capture complementary aspects of aneurysmal remodeling.

bioengineering↗

bioRxiv2026

In vivo optical clearing of the mouse brain

Light microscopy is one of the most powerful tools for understanding living systems, but the opacity of tissue prevents visualization of all but superficial layers. Several methods to clarify tissue have been developed, but most require fixed specimens. To address the challenge of improving resolution in functioning neuronal circuits, we developed a biocompatible clearing agent, iodixanol-ACSF, which is capable of increasing the transparency of living neuronal tissue. Brain-cleared mice were motile and unimpaired on a variety of behavioral tasks, and extracellular recordings showed that many cellular and circuit phenomena were well-preserved. In live iodixanol-ACSF cleared mouse brain tissue, both transmission and cellular-resolution fluorescence microscopy indicate improvements of 150-200% in penetration depth with one-third to one-half the laser intensity when compared to untreated tissue. Our results show that iodixanol-ACSF clearing will enable deeper imaging and extend our understanding of neuronal circuit function.

neuroscience↗

bioRxiv2026

Causal Language Detection using Text-Document Features: Methodology and Insights from 10 Years of Gut Microbiome Research

Detecting causal language in scientific literature is critical for understanding how research fields frame evidence and inform interventions and policies, yet existing approaches commonly rely on manual annotation. The objective of this study was to evaluate four classifiers for detecting causal language and to apply the best-performing model to assess trends in microbiome research. Microbiome research, with its rapidly expanding observational literature, provides a relevant case study. We extracted Term Frequency-Inverse Document Frequency (TF-IDF) features from the last three sentences of available publication abstracts and trained four classifiers (L1- and L2-regularized logistic regression, Random Forest, and eXtreme Gradient Boosting) to detect causal language. A total of 475 sentences, as determined pragmatically based on annotation feasibility and observed stabilization of model performance, were manually labeled as causal or non-causal following established guidelines for systematic evaluation of causal language in observational health research. Of these, 75% of sentences were used for training and 25% for testing. L1-regularized logistic regression achieved the highest performance (accuracy 76%, F1 72%, prevalence detection accuracy 95%, sensitivity 72%, and specificity 80%) and was applied to 20,022 human gut microbiome abstracts published between 2015 and 2025 grouped into 20 thematic topics using structural topic modeling. Predicted causal language prevalence declined from 52% to 44% between 2015 and 2018, then rose to 51% by 2025, with notable variation across topics (range: 43.1-53.3%). Temporal trends differed across subfields, with increases in Metabolic disorders, Fecal microbiota transplantation, and decreases in Biomarkers and prediction, Antibiotic resistance, and In vitro fermentation. Analysis of influential words confirmed that causal meaning is primarily driven by verbs and modifiers lexically signaling change or intervention. The proposed approach for identifying causal claims in scientific abstracts enables systematic and automated, scalable assessment of how evidence is framed. Its application to the microbiome field highlighted heterogeneity in the reporting of causal relationships and informing the interpretation of microbiome findings for clinical and public health decision-making.

scientific communication and education↗

bioRxiv2025

Artificial Intelligence-enabled Histological Analysis in Preclinical Respiratory Disease Models: A Scoping Review

Histological analysis is a cornerstone of preclinical respiratory disease research, enabling assessment of pathology, therapeutic effects, and mechanisms. However, conventional approaches rely on manual scoring, which is subjective, time-consuming, and difficult to scale due to low throughput and inter-observer variability. Artificial intelligence (AI), particularly deep learning, offers potential to automate histology workflows, but its use and evaluation in preclinical respiratory models have not been synthesized. We conducted a scoping review following Joanna Briggs Institute guidelines, searching MEDLINE and Embase (inception-January 2025) for preclinical studies using AI to analyze histology in respiratory disease models. Screening, full-text review, and data extraction were performed in duplicate. Of 6271 studies screened, 29 met inclusion criteria. Most used murine models (76%) and investigated lung cancer (28%), pulmonary fibrosis (24%), or tuberculosis (17%). Hematoxylin and eosin was the most common stain (48%), with others targeting collagen or immune markers. AI tasks included image classification (n=20), segmentation (n=10), and object detection (n=4), predominantly using convolutional neural networks (69%). Preprocessing methods (e.g., stain normalization) were common, but annotation and training practices were inconsistently reported. Performance was generally high (accuracy [≥]90%; 7 studies) though validation metrics varied, and external validation was absent. Most studies used "black box" models, with minimal application of explainability techniques. Reproducibility measures, such as sharing datasets or code were rarely reported. AI tools are poised to transform histological analysis in preclinical respiratory research. By addressing gaps in validation, transparency, and standardization, the field can harness these technologies to deliver robust, efficient, and scalable workflows. Registration: Open Science Framework https://doi.org/10.17605/OSF.IO/NM94E

cell biology↗

bioRxiv2025

Single-cell Characterization of DNA Hydroxymethylation of the Mouse Brain During Aging

DNA methylation dynamics, including 5-hydroxymethylcytosine (5hmC) and 5-methylcytosine (5mC), critically regulate brain function, yet conventional methods cannot distinguish these modifications, obscuring their distinct roles in gene regulation and aging. We present Joint- Cabernet, a bisulfite-free single-cell platform enabling simultaneous profiling of 5hmC, 5mC, and transcriptomes. Applying Joint-Cabernet to 84,071 nuclei from adult and aged mouse brains, we resolved cell-type-specific DNA hydroxymethylation landscapes, revealing elevated 5hmCG and 5hmCH levels in transcriptionally active genes across neuronal subtypes and spatial gradients in cortical layers. During aging, 5hmCG accumulates globally but is selectively enriched at open chromatin loci, aligning with the upregulation of cell-type-specific genes in distinct brain cell types. This single-cell DNA methylation brain cell atlas provides a framework for studying methylation- driven mechanisms in brain aging and neurodegenerative diseases.

genetics↗

bioRxiv2024

A novel method for characterizing cell-cell interactions at single-cell resolution reveals unique signatures in blood T cell-monocyte complexes during infection

Communication between immune cells through direct contact is a critical feature of immune responses. Here, we developed a novel high-throughput method to study the transcriptome and adaptive immune receptor repertoire of single cells forming complexes without needing bioinformatic deconvolution. We found that T cells and monocytes forming complexes in blood during active tuberculosis (TB) and dengue hold unique transcriptomic signatures indicative of TCR/MCH-II immune synapses. Additionally, T cells in complexes showed enrichment for effector phenotypes, imaging and transcriptomic features of active TCR signaling, and increased immune activity at diagnosis compared to after anti-TB therapy. We also found evidence for bidirectional RNA exchange between T cells and monocytes, since complexes were markedly enriched for "dual-expressing" cells (i.e., co-expressing T cell and monocyte genes). Thus, studying immune cell complexes at a single-cell resolution offers novel perspectives on immune synaptic interactions occurring in blood during infection. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=59 SRC="FIGDIR/small/612103v1_ufig1.gif" ALT="Figure 1"> View larger version (17K): org.highwire.dtl.DTLVardef@f90023org.highwire.dtl.DTLVardef@178007corg.highwire.dtl.DTLVardef@167e53corg.highwire.dtl.DTLVardef@1faff48_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2024

Deciphering the Transcription Factor Landscape in Neuroendocrine Prostate Cancer Progression: A Novel Approach to Understand NE Transdifferentiation

Background and ObjectiveProstate cancer (PCa) is a leading cause of cancer mortality in men, with neuroendocrine prostate cancer (NEPC) representing a particularly resistant subtype. The role of transcription factors (TFs) in the progression from prostatic adenocarcinoma (PRAD) to NEPC is poorly understood. This study aims to identify and analyze lineage-specific TF profiles in PRAD and NEPC and illustrate their dynamic shifts during NE transdifferentiation. MethodsA novel algorithmic approach was developed to evaluate the weighted expression of TFs within patient samples, enabling a nuanced understanding of TF landscapes in PCa progression and TF dynamic shifts during NE transdifferentiation. Resultsunveiled TF profiles for PRAD and NEPC, identifying 126 shared TFs, 46 adenocarcinoma-TFs, and 56 NEPC-TFs. Enrichment analysis across multiple clinical cohorts confirmed the lineage specificity and clinical relevance of these lineage-TFs signatures. Functional analysis revealed that lineage-TFs are implicated in pathways critical to cell development, differentiation, and lineage determination. Novel lineage-TF candidates were identified, offering potential targets for therapeutic intervention. Furthermore, our longitudinal study on NE transdifferentiation highlighted dynamic TF expression shifts and delineated a three-phase hypothesis for the process comprised of de-differentiation, dormancy, and re-differentiation. and proposing novel insights into the mechanisms of PCa progression. ConclusionThe lineage-specific TF profiles in PRAD and NEPC reveal a dynamic shift in the TF landscape during PCa progression, highlighting three distinct phases of NE transdifferentiation.

cancer biology↗

bioRxiv2024

PRMT5 deficiency disturbs Nur77 methylation to inhibit endometrial stromal cell differentiation in recurrent implantation failure

Various posttranslational modifications (PTMs) have been implicated in endometrial stromal cell (EnSC) differentiation, but the potential role of PTM crosstalk has not been identified. Here, we report that protein arginine methyltransferase 5 (PRMT5) is indispensable for human endometrial decidualization, functioning as a key regulator of decidualization defect in recurrent implantation failure (RIF) patients. Uterine-selective deletion of Prmt5 led to defective embryo implantation in mice due to impaired EnSC decidualization. Mechanistically, we find that PRMT5 catalyzes symmetric dimethylation of orphan nuclear receptor Nur77 at arginine 346, which in turn promotes Nur77 nuclear localization and increases its transcriptional activity in EnSC. Moreover, we demonstrate that PRMT5-mediated Nur77 methylation antagonizes AKT-induced phosphorylation of Nur77 at serine 351 in the transition from proliferation to differentiation of EnSC and disruption of the balance between methylation and phosphorylation of Nur77 is essentially involved in the endometrium of RIF patients. Furthermore, by modulating the methylation-phosphorylation of Nur77 and its transcriptional activity, we rescued impaired decidualization in RIF, further highlighting the critical role of the PRMT5/AKT/Nur77 complex in uterine receptivity to embryo implantation.

cell biology↗

bioRxiv2023

Polyubiquitinated PCNA promotes alternative lengthening of telomeres by inducing break-induced replication

Replication stresses are the major source of break-induced replication (BIR). Here, we show that in alternative lengthening of telomeres (ALT) cells, replication stress-induced polyubiquitinated PCNA (polyUb-PCNA) triggers BIR at telomeres and the common fragile site (CFS). Consistently, depleting RAD18, a PCNA ubiquitinating enzyme, reduces the occurrence of ALT-associated PML bodies (APBs) and mitotic DNA synthesis at telomeres and CFS, both of which are mediated by BIR. In contrast, inhibiting USP1, an Ub-PCNA deubiquitinating enzyme, results in an increase in the above phenotypes in a RAD18- and UBC13 (the PCNA polyubiquitinating enzyme)-dependent manner. Furthermore, deficiency of ATAD5, which facilitates USP1 activity and unloads PCNAs, augments recombination-associated phenotypes. Mechanistically, telomeric polyUb-PCNA accumulates SLX4, a nuclease scaffold, at telomeres through its ubiquitin-binding domain and increases telomere damage. Consistently, APB increase induced by Ub-PCNA depends on SLX4 and SLX4-associated nucleases. Taken together, our results identified the polyUb-PCNA-SLX4 axis as a trigger for directing BIR.

cell biology↗

bioRxiv2022

FoxP3-mediated blockage of ryanodine receptor 2 is the molecular basis for the contact-based suppression by regulatory T cells

The suppression mechanism of regulatory T cells is an intensely investigated topic. As our focus has shifted towards a model centered on indirect inhibition of dendritic cells, a universally applicable effector mechanism controlled by FoxP3 expression has not been found. Here, we report that FoxP3 blocks the transcription of ER Ca2+-release channel ryanodine receptor 2. Reduced RyR2 shuts down basal Ca2+ oscillation in Tregs, which reduces m-Calpain activities that is needed for T cells to disengage from DCs, suggesting a persistent blockage of DC antigen presentation. RyR2 deficiency renders the CD4+ T cell pool to become immune suppressive, and behave in the same manner as FoxP3+ Tregs in viral infection, asthma, hypersensitivity, colitis and tumor development. In the absence of FoxP3, RyR2-deficient CD4+ T cells rescue the systemic autoimmunity associated with Scurfy mice. Therefore, FoxP3-mediated Ca2+ signaling inhibition may be a central effector mechanism of Treg immune suppression. One Sentence SummaryCalcium channel RyR2 dictates Treg adhesion-based suppression

immunology↗

bioRxiv2022

Temporal and spatial dynamics mapping reveals follicle development regulated by different stromal cell populations

Follicle development is a complex dynamic process. The follicles are encapsulated in the stroma, and once the follicle develops, the follicle moves from the cortex to the medulla and finally to the cortex to ovulate in the process of continuous growth. Many of these processes cannot be explained with the follicle alone. Through single-cell and spatial transcriptome sequencing at key time points of follicular development in mice after birth, we found that ovarian stromal cells are not only one of the main cell groups that make up the ovary but that their cell population and spatial location are also closely related to follicular development. Through analysis of cell communication, it was found that ovarian stromal cells were the main transmitters of intercellular communication, and many of the signals they sent were received by granulosa cells and oocytes to participate in follicle development. Ovarian stromal cells are not a homogeneous cell population. We combined single cell types with their spatial location information to divide ovarian stromal cells into four types, namely, structural stromal cells, perifollicular stromal cells, stromal progenitor cells, and steroidogenic stromal cells, each of which plays a different function in follicle development. Indepth studies of the different spatial locations and different types of stromal cells will expand our understanding of follicle development dynamics, leading to new targets and novel approaches for the treatment of ovarian-related diseases.

developmental biology↗

bioRxiv2021

Proteome of actin stress fibers

Stress fibers (SFs), which are actomyosin structures, reorganize in response to various cues to maintain cellular homeostasis. Currently, the protein components of SFs are only partially identified, limiting our understanding of their responses. Here we isolate SFs from huma fibroblasts HFF-1 to determine with proteomic analysis the whole protein components and how they change with replicative senescence (RS), a state where cells decline in ability to replicate after repeated divisions. We found that at least 263 proteins are associated with SFs, and 101 of them are upregulated with RS, by which SFs become larger in size. Among them, we focused on eEF2 (eukaryotic translation elongation factor 2) as it exhibited upon RS the most significant increase in abundance. We show that eEF2 is critical to the reorganization and stabilization of SFs in senescent fibroblasts. Our findings provide a novel molecular basis for SFs to be reinforced to resist cellular senescence.

cell biology↗

bioRxiv2020

Statistical profiling reveals correlations between the cell response to and structural sequence of Rho-GAPs

Rho-GTPase-activating proteins (Rho-GAPs) are essential upstream regulators of the Rho family of GTPases. Currently, it remains unclear if the phenotypic change caused by perturbations to a Rho-GAP is predictable from its structural sequence. Here we analyze the relationship between the morphological response of cells to the silencing of Rho-GAPs and their primary structure. For all possible pairs of 57 different Rho-GAPs expressed in MCF10A epithelial cells, the similarity in the Rho-GAP silencing-induced morphological change was quantified and compared to the similarity in the primary structure of the corresponding pairs. We found a distinct correlation between the morphological and structural similarities in a specific group of RhoA-targeting Rho-GAPs. Thus, the family-wide analysis revealed a common feature shared by the specific Rho-GAPs.

cell biology↗

bioRxiv2020

Dynamic fluctuations of the locus coeruleus-norepinephrine system underlie sleep state transitions

We normally regard sleep and wake as two distinct opposing brain states, where sleep requires silence of wake-promoting structures such as the locus coeruleus (LC)-norepinephrine (NE) system. We set out to investigate how cortical NE dynamics and NE-related astrocytic activity relates to LC population activity during sleep states. We show that LC displays regular phasic activity bouts during NREM sleep leading to a slow oscillatory pattern of prefrontal NE levels of which the majority of NE increases does not lead to awakening. NE troughs link to sleep spindles and continued NE decline transitions into REM sleep. Last, we show that prefrontal astrocytes have reduced sensitivity towards NE during sleep. Our results suggest that dynamic changes in the activity of wake-promoting systems during sleep create alternation between crucial sleep processes and broadening of sensitivity towards incoming sensory input. HighlightsO_LIExtracellular levels of norepinephrine display dynamic changes during NREM and REM sleep C_LIO_LIPhasic activity of locus coeruleus neurons during NREM underlies slow norepinephrine oscillations C_LIO_LISpindles occur at norepinephrine troughs and are abolished by norepinephrine increases C_LIO_LIIncreased spindles prior to REM reflect the beginning of a long-lasting norepinephrine decline C_LIO_LIREM episodes are characterized by a sub-threshold continuous norepinephrine decline C_LIO_LIThe responsiveness of astrocytic Ca2+ to norepinephrine is reduced during sleep C_LI

neuroscience↗

bioRxiv2019

Correlation of IL-17 level in gingival crevicular fluid of orthodontically induced inflammatory root resorption

ObjectiveTo investigate IL-17 expression in orthodontic tooth movement and orthodontic nickel-titanium spring-induced inflammatory root resorption.\n\nMethodsOrthodontic nickel-titanium springs were ligated between the bilateral maxillary first molar and the incisors of the rats to establish a rat model of orthodontic tooth movement (OTM), each rat was subjected to two cycles of near-GCF and peripheral blood serum collection before and after force application, and IL-17 levels in GCF and serum were measured quantitatively by ELISA. Morphological changes in periodontal tissue and root of the experimental dentine were evaluated by hematoxylin and eosin staining. Tartrate-resistant acid phosphatase staining and immunohistochemistry were used to determine the osteoclast number and expression changes in IL-17, receptor activator of nuclear factor kappa-B ligand (RANKL), and osteoprotegerin (OPG) in the periodontal tissues, respectively, on the pressure side of the experimental tooth.\n\nResultsIL-17 was detected in GCF and serum. The pressure area exhibited alveolar bone resorption only at a force of 20g. Additionally, a force of 60g led to root resorption. IL-17, RANKL/OPG and osteoclast number showed similar trend that all expressed increasing high level at early stage, then significantly decreased from days 5 to 14, and revealed 60g group the highest expression level while 0g group the lowest.\n\nThe change in the IL-17 level in the GCF was strongly correlated with IL-17 and RANKL/OPG expression levels and osteoclast numbers in the periodontal ligament.\n\nConclusionsThe results indicated that measuring IL-17 level in GCF can predict the risk of alveolar bone and root resorption induced by orthodontic treatment.

animal behavior and cognition↗