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Biology subjects

Shen, H.

Publications and source records attributed to Shen, H..

At least 37 records · Page 2Linked to original sources

ATLAS: Population-Level Disease Locus Discovery via Differential Attention in Genomic Language Models

Identifying disease-associated genetic variants remains a key challenge in genomics, especially in small cohorts or for rare and complex mutation types where genome-wide association studies (GWAS) often fall short. We introduce ATLAS, a population-level framework that leverages attention signals from pretrained genomic language models (gLMs) to detect disease-associated genes and loci directly from raw sequences--without requiring explicit variant calls or supervised training. ATLAS first performs gene-level differential attention analysis to prioritize candidate genes, followed by base-level analysis to localize disease-associated regions at single-haplotype resolution. We validate ATLAS on synthetic and {beta}-thalassemia datasets, demonstrating robust performance across diverse allele frequencies (down to 10%), cohort sizes (below 200 individuals per group), and genomic scales. Compared to GWAS, ATLAS achieves higher recall of known loci and captures haplotype-specific signals missed by traditional methods. Cross-model benchmarking further shows that precise localization depends on both model size and pretraining on diverse human genomes. In summary, ATLAS offers a scalable, sequence-native alternative to traditional statistical genetics.

genetics↗

Molecular Mechanisms Associated With Amelioration Of Radiation Induced Gastrointestinal Mucositis By Compound Kushen Extracts

Radiation induced gastrointestinal mucositis (GIM) is a severe complication of radiotherapy that compromises patient quality of life and treatment efficacy. This study assessed the therapeutic potential and molecular mechanisms of two forms of herbal extracts, Compound Kushen Powder (CKP) and Compound Kushen Injection (CKI) in a rat model of GIM. Administration of either CKP or CKI to irradiated animals significantly reduced the severity of GIM symptoms. Transcriptomic analysis of jejunum and colon mucosa identified candidate mechanisms as well as common pathways between CKP and CKI. CKP modulated innate immune activation and inflammatory signalling, affecting genes such as Socs3 and Tlr4, while CKI promoted tissue repair and oxidative stress resistance through genes including Osm, Epha2, and Stat3. However, both forms of herbal extract enhanced stress response and stimulus regulation in our GIM model. These findings reveal common mechanisms shared by CKP and CKI that suppress symptoms of radiation induced GIM, along with extract specific effects on distinct pathways, acting on different set of genes.

molecular biology↗

Mitochondrial dsRNA: A Hidden Source of Immunogenic RNA in ADAR1 Deficiency

Double-stranded RNA (dsRNA) triggers immune responses during viral infections, but self-derived dsRNA can activate similar pathways. To prevent this, the body relies on mechanisms like ADAR1, an RNA-editing enzyme essential for immune regulation. Dysfunction of ADAR1 is linked to various diseases, yet the nature and role of dsRNAs accumulating in its absence remain unclear. Here, we identify mitochondrial dsRNA (mt-dsRNA), transcribed from the mitochondrial genome, as a major contributor to the endogenous dsRNA pool in ADAR1-deficient human and murine cells. We propose a "Draw-and-Release" model, where ADAR1 loss increases mitochondrial reactive oxygen species (mtROS), causing mt-dsRNA accumulation in the mitochondrial matrix ("Draw" phase) and its immune-activating release into the cytosol upon mitochondrial protein dysfunction ("Release" phase). This study highlights the importance of mitochondrial integrity in mitigating ADAR1-related pathologies.

cell biology↗

Leveraging Human Pangenome for Improved Somatic Variant Detection

Somatic variant detection is technically challenging due to low variant allele fractions, the confounding presence of germline variation, and reference bias. Linear references such as GRCh38 miss sample-specific variation, causing misalignments and incorrect variant calls. Although telomere-to-telomere donor-specific assemblies (DSAs) accurately represent individual genomes, their application is limited by cost and technical barriers. Alternatively, the graph-based human pangenome provides a scalable framework to improve read alignment and perform genome inference. Here, we benchmarked somatic variant detection using GRCh38, graph-based pangenomes, and pangenome-inferred DSAs with a HapMap mixture dataset and the COLO829 melanoma cell line. Pangenome-guided alignment improves read mapping and somatic variant calling accuracy. Furthermore, personalized pangenomes partially reconstruct donor-specific genomic content, improving accuracy, reducing germline contamination, and enabling detection of events in loci absent or poorly represented in GRCh38. These findings demonstrate that graph-based and personalized pangenomes are effective strategies for enhancing somatic variant detection compared with GRCh38.

genomics↗

Developmental Trajectories of Addition and Subtraction in Early School-aged Children

Mastering basic arithmetic lays the foundation for lifelong mathematical achievement, yet how the neural mechanisms underlying addition and subtraction calculations develop during childhood remain unclear. This study investigated the developmental trajectories of addition and subtraction calculations in school-aged children, and explored how arithmetic-specific neural responses in the right parieto-occipital region are related to age-related improvements in behavioral performance. Here, we recorded electroencephalography (EEG) signals from 115 typically developing children divided into three age groups (7-8-, 9-10-, and 11-12-year-olds) during an arithmetic task involving addition and subtraction calculations. We analyzed the P300 component from the original waveforms and the {Delta}P300 component from the difference waveforms, which were generated by subtracting the event-related potentials (ERPs) elicited by the first operand from those elicited by the second operand to isolate arithmetic-specific neural processes. The results revealed that, in both calculations, older children showed better behavioral performance (faster reaction time and larger PI) and greater right parieto-occipital {Delta}P300 amplitudes, with a key developmental stage at 11-12 years. Furthermore, all groups of children exhibited greater right parieto-occipital P300 and {Delta}P300 amplitudes in subtraction, whereas the smaller right parieto-occipital {Delta}P300 amplitudes in addition significantly mediated the relationship between age and PI. These findings reveal distinct patterns for addition and subtraction calculations over development, highlighting the right parieto-occipital {Delta}P300 amplitude as a neural marker of arithmetic performance, particularly for addition calculation.

neuroscience↗

Tumor cell dissemination is facilitated through regulatory T cell-driven extracellular matrix remodeling

Regulatory T (Treg) cells function to enforce peripheral tolerance and are potent suppressors of tumor immunity. In breast cancer, we have shown that Treg cells promote tumor growth by favoring alternative activation of macrophages via suppression of IFN-{gamma}. The tumor-associated extracellular matrix (ECM) is a key regulator of metastatic dissemination and is emerging as a critical regulator of tumor immunity. However, the reciprocal effects of the immune system on the ECM remain elusive. Using a combination of murine in vivo, ex vivo and bioengineering models we describe Treg cell-dependent changes in the tumor ECM that facilitate tumor cell migration and metastatic dissemination. Importantly, Treg cell-dependent matrisome signatures correlate with delayed survival advantage in human breast cancer samples, and are upregulated in tumor-associated macrophages (TAMs). Further, both IFN-{gamma} and IFN-{gamma}-sensitivity in TAMs contribute to structural and functional changes of the ECM. This work underscores a previously unrecognized role of Treg cells on the ECM that facilitates metastasis and is consistent with tissue Treg cell emergent function as critical regulators of tissue repair and cancer.

cancer biology↗

Single-Cell Immune Profiling Reveals Non-classical Monocyte-Driven Immunodepression in Tuberculosis Treatment Non-Responders

Sputum culture conversion (SCC) at 2 months is a critical predictor of tuberculosis (TB) treatment outcomes, yet the underlying immune alterations driving treatment non-response remain unclear. We performed single-cell RNA sequencing on peripheral blood mononuclear cells from 8 TB patients, stratified by 2-month SCC status, to characterize cellular heterogeneity and intercellular communication. Treatment non-responders exhibited marked expansion and terminal differentiation of non-classical monocytes with elevated TB progression risk signatures. These cells showed reduced outgoing but enhanced incoming signaling, prominently via IL-16 and TRAIL pathways, potentially amplifying regulatory T cell (Treg)-mediated immunosuppression. CD4 Tregs in non-responders engaged in intensified GALECTIN signaling toward CD8 cytotoxic T cells and mature NK cells, contributing to effector cell exhaustion. NK cell subsets, particularly mature NK c2, displayed increased inhibitory receptor expression and terminal differentiation states. Our findings delineate a dysregulated "non-classical monocyte -Treg -cytotoxic lymphocyte" axis in TB treatment failure, highlighting candidate biomarkers and host-directed therapeutic targets.

bioinformatics↗

When migration leaves a clean trace: Decoupling migration from coalescence in the Structured Serial Coalescent

With the rapid accumulation of population genomic data across space and time, there is an urgent need for demographic inference methods that incorporate explicit time-series modeling, achieve high spatial scalability, and ensure clear identifiability between migration and coalescence rates. To address this need, we investigate pairwise genealogical processes under the structured serial coalescent, deriving evolution equations for pairwise branch length distributions and related statistics. By classifying the resulting identities according to their parameter dependencies and computational complexity, we identify a class that is not only computationally tractable but also determined exclusively by migration rates. Building on this theoretical basis, we propose a scalable framework for inferring time-varying migration rates and demonstrate its feasibility through simulation. We further outline how this framework can be extended to the joint estimation of migration and coalescence rates.

evolutionary biology↗

Multi-platform framework for mapping somatic retrotransposition in human tissues

Mobile element insertions (MEI) shape the human genome in both germline and somatic tissues. While inherited MEIs are well characterized, mapping somatic MEIs (sMEI) in non-cancer tissues remains challenging due to their low allelic fraction and repetitive nature. We established an integrative framework for sMEI analysis leveraging modern sequencing technologies and analytical innovations. We first benchmarked sMEI detection and demonstrated advantages of long-read and MEI-targeted sequencing for ultra-low-frequency events using a mixture of well-established cell lines. We then showed that haplotype phasing and donor-specific assemblies refine sMEI detection, effectively distinguishing from germline and false signals in in-silico tumor-normal mixtures. We further developed a source-tracing strategy based on internal sequence variation, expanding the catalogue of active source elements beyond traditional transduction-based methods. Applying this framework to donor tissues, we identified 18 rare somatic L1 insertions, revealing structural and source diversity. Our work provides a foundational framework and biological insight into sMEIs.

genomics↗

Loss of tight junction protein claudin 18 uncovers alveolar epithelial stem cell plasticity and emergence of non-fibrogenic transitional progenitors

Persistence of senescent alveolar transitional progenitors following lung injury is implicated in the pathogenesis of fibrosis. We identified transitional cells in uninjured Cldn18 knockout (KO) mouse lungs distinct from previously reported damage-associated transitional progenitors (DATPs) with a less fibrogenic transcriptomic profile. Cldn18 KO mice are protected from bleomycin-induced fibrosis, with early restoration of cellular homeostasis. Lineage tracing implicates accelerated differentiation as a mechanism for protection from fibrosis, leading us to name these cells regeneration-associated transitional progenitors (RATPs). Multiome confirms that RATPs and DATPs are epigenetically distinct, with RATPs comprised of RATP2s and RATP1s based on epigenomic proximity to AT2s and AT1s, respectively, and suggests dynamic regulatory remodeling during AT2-to-AT1 differentiation, with NKX2.1 and AP-1 active in early transitions and TEAD factors in later stages. These results reveal an unexpected role for Cldn18 in regulation of AEC plasticity, while identification of RATPs challenges the notion that persistence of transitional alveolar cells is invariably pathologic.

cell biology↗

De-novo design of a random protein walker

Molecular machines hold great potential. Design of static monomeric and oligomeric protein structures has advanced tremendously, but few dynamic protein systems have been designed. Here we present the design and characterization of a random protein walker that diffuses along a designed protein track. For the track, we designed micro-meter long fibres and developed a method to rigidly decorate them with arbitrary proteins. The walkers consist of homo-oligomers that reversibly bind the track using heterodimeric feet; we tested multiple heterodimer interfaces for reversibility and designed six walkers with different numbers of feet. Cryo-EM experiments confirmed the structure of the track and walkers. We performed detailed single molecule tracking and kinetics characterisation and found that the walkers with more feet diffuse along the track faster. The system represents a tuneable starting point for future powered protein molecular robots.

synthetic biology↗

A Pangenomic Method for Establishing a Somatic Variant Detection Resource in HapMap Mixtures

Somatic mosaicism is essential in human biology and disease, yet robust benchmarks are scarce. The SMaHT Consortium mixed six HapMap cell lines to create artificial somatic variants spanning 0.25% to 16.5% variant allele fractions. We developed a technology-agnostic method that builds pangenome graphs from individual assemblies to create unified benchmarking sets: > 6M single-nucleotide variants, 1.8M small insertions/deletions, 49K structural variations, and 10K mobile element insertions across autosomes, X, and mitochondrial chromosomes. We validated the variants using ultra-deep simulated reads and developed a binomial-based model to estimate coverage requirements for variant detection. Evaluating multiple callers showed CHM13 alignment improves structural variant detection and offers advantages in difficult-to-map regions compared to GRCh38. Systematic characterization showed regions with low detection rate are enriched in centromeres, satellite sequences, tandem repeats, and falsely duplicated genes. This accurate, versatile resource enables systematic evaluation of somatic variant detection technologies.

genomics↗

An AI Agent for cell-type specific brain computer interfaces

Decoding how specific neuronal subtypes contribute to brain function requires linking extracellular electrophysiological features to underlying molecular identities, yet reliable in vivo electrophysiological signal classification remains a major challenge for neuroscience and clinical brain-computer interfaces (BCI). Here, we show that pretrained, general-purpose vision-language models (VLMs) can be repurposed as few-shot learners to classify neuronal cell types directly from electrophysiological features, without task-specific fine-tuning. Validated against optogenetically tagged datasets, this approach enables robust and generalizable subtype inference with minimal supervision. Building on this capability, we developed the BCI AI Agent (BCI-Agent), an autonomous AI framework that integrates vision-based cell-type inference, stable neuron tracking, and automated molecular atlas validation with real-time literature synthesis. BCI-Agent addresses three critical challenges for in vivo electrophysiology: (1) accurate, training-free cell-type classification; (2) automated cross-validation of predictions using molecular atlas references and peer-reviewed literature; and (3) embedding molecular identities within stable, low-dimensional neural manifolds for dynamic decoding. In rodent motor-learning tasks, BCI-Agent revealed stable, cell-type-specific neural trajectories across time that uncover previously inaccessible dimensions of neural computation. Additionally, when applied to human Neuropixels recordings-where direct ground-truth labeling is inherently unavailable-BCI-Agent inferred neuronal subtypes and validated them through integration with human single-cell atlases and literature. By enabling scalable, cell-type-specific inference of in vivo electrophysiology, BCI-Agent provides a new approach for dissecting the contributions of distinct neuronal populations to brain function and dysfunction.

neuroscience↗

Abnormal shear stress induces ferroptosis in endothelial cells via KLF6 downregulation

Stable laminar flow maintains vascular tone regulation, while abnormal blood flow, such as disturbed flow or extreme shear stress, causes endothelial dysfunction, but the underlying mechanism is yet to be explored. We used a microfluidic device to deform flat microchannel into tunnel-like macrochannel. The cross-sectional area of this macrochannel varies with the flow rate and the thickness of the deformable layer, creating three levels of shear stress: low (0.99 dyn/cm2, LSS), medium (4.78 dyn/cm2, MSS), and high (24 dyn/cm2, HSS). Comparing different shear stress exposure to endothelial cells for 24 h, prominent ferroptosis features emerged under either LSS or HSS compared to MSS. These features included increased C11 BODIPY-labeled lipid peroxidation and 4-hydroxynonenal accumulation, CoQ10 depletion, reduced SLC7A11 protein expression, and diminished cell death with Ferrostatin-1 treatment. RNA-seq analysis (LSS/MSS) showed that LSS significantly downregulated transcription of cholesterol homeostasis and unfolded protein response (UPR). Compared to MSS, Western blot results showed that both LSS and HSS reduced the expression of two key enzymes (MVD and IDI1) in the mevalonate pathway, as well as the expression of two main UPR signaling regulators (PERK and BiP). Based on the binding prediction between transcription factors and gene promoters from differentially expressed genes identified through RNA-seq, we found KLF6 to be a key transcription factor. It regulates the PERK-mediated UPR and the mevalonate pathway, which are associated with SLC7A11 expression and CoQ10 synthesis, respectively. The overexpression of KLF6 restored SLC7A11 and CoQ10 levels under both LSS and HSS, significantly reducing foam cell formation, monocyte adhesion, and lipid peroxidation. Our findings reveal KLF6 as a crucial regulator of atherosclerosis induced by abnormal shear stress.

cell biology↗

Reprogramming Factors Activate a Non-Canonical Oxidative Resilience Pathway That Can Rejuvenate RPEs and Restore Vision

Oct4, Sox2, and Klf4 (OSK) Yamanaka factors induce pluripotency and reverse age-related epigenetic changes, yet the mechanisms by which they promote rejuvenation remain poorly explored. Oxidative stress contributes to CNS aging and retinal pigmented epithelium (RPE) degeneration in age-related macular degeneration. We find that OSK expression in RPE restores retinal structure and visual function in aged mice and promotes oxidative resilience through a non-canonical, Tet2-independent pathway. Integrative functional genomics identifies GSTA4, a detoxifying enzyme that clears the lipid peroxidation byproduct 4-HNE, as a necessary and sufficient OSK effector. Dynamic GSTA4 regulation by OSK recapitulates a stem cell derived stress resilience program. GSTA4 overexpression alone enhances mitochondrial resilience, rejuvenates the aged RPE transcriptome, and reverses visual decline. GSTA4 is consistently upregulated across diverse lifespan-extending interventions suggesting a broader pro-longevity role. These findings uncover a previously unrecognized protective axis driven by Yamanaka factors that circumvents reprogramming, providing therapeutic insights for age-related diseases. HIGHLIGHTSO_LIOSK-GSTA4 provides a dynamic, Tet2-independent stress-resilience axis. C_LIO_LIFunctional genomics pinpoints GSTA4 as a direct downstream effector activated by OSK. C_LIO_LIRPE aging involves progressive accumulation of 4-HNE that can be detoxified by GSTA4. C_LIO_LIEnhancing GSTA4 rejuvenates RPE cells, restores vision and is associated with lifespan-extending interventions. C_LI

genetics↗

Trustworthy detection of exencephaly in high-throughput micro-CT embryo screens with focal-loss transformers

1.Lethal and sub-viable knockout mouse lines require whole-embryo 3D imaging to connect genotype to phenotype (Dickinson et al., 2016; Cacheiro et al., 2022). There are often far fewer samples of in-class (e.g., homozygous knockouts) than wildtype or normative samples. Such extreme subject-level imbalance degrades both statistical anatomy and deep learning, often yielding saliency maps that highlight noise rather than lesion-specific signal (Adebayo et al., 2018; Buda et al., 2018; Johnson & Khoshgoftaar, 2019). We therefore asked whether focal loss (Lin et al., 2017) in combination with model-capacity control and seed ensembling can stabilize explanations without compromising classification accuracy. Exencephaly is an neural tube defect characterized by incomplete closure of the cephalic neural tube and dorsally exposed,disorganized neural tissue (Greene & Copp, 2014; Noden & de Lahunta, 1985). In our late-gestation screen, approximately 10% of embryos had exencephaly, creating severe class imbalance and underscoring the need for interpretable automation. As a test case for imbalance-aware, interpretable phenotyping, we analyzed 253 diceCT scans of E15.5 embryos (24 with exencephaly). A self-supervised transformer was fine-tuned with three regimes: cross-entropy (CE-Large), focal-loss equal-capacity (FL-Large) and focal-loss reduced-capacity (FL-Small). Five random seeds per regime yielded 15 models. Integrated Gradients saliency was quantified, and explanation quality was measured by saliency entropy (sparsity), cross-seed Dice/Jaccard similarity (reproducibility), and expert visual inspection. All 15 models achieved near perfect phenotype recognition on held-out data with 0.996 {+/-} 0.002 mean accuracy with some seeds/regimens reached 1.000. Focal loss reduced saliency entropy by up to 1.5 bits and doubled cross-seed Dice overlap, concentrating attribution on the malformed cranial vault. Ensemble-averaged heat-maps show that both focal-loss regimes concentrate attribution on the malformed cranial vault while suppressing spurious body-wide signals. Focal loss, modest capacity, and seed ensembling within a modified M3T transformer yielded sparse, reproducible, anatomically focused attribution while preserving perfect sensitivity. This supports trustworthy high-throughput phenotyping in severely imbalanced embryo screens. The workflow relies only on standard atlas registration and image pre-processing, requires no voxel-level annotations, and is readily adaptable to other structural malformations and developmental stages.

developmental biology↗

Tranquillyzer: A Flexible Neural Network Framework for Structural Annotation and Demultiplexing of Long-Read Transcriptomes

Long-read single-cell RNA sequencing using platforms such as Oxford Nanopore Technologies (ONT) enables full-length transcriptome profiling at single-cell resolution. However, high sequencing error rates, diverse library architectures, and increasing dataset scale introduce major challenges for accurately identifying cell barcodes (CBCs) and unique molecular identifiers (UMIs) - key prerequisites for reliable demultiplexing and deduplication, respectively. Existing pipelines rely on hard-coded heuristics or local transition rules that cannot fully capture this broader structural context and often fail to robustly interpret reads with indel-induced shifts, truncated segments, or non-canonical element ordering. We introduce Tranquillyzer (TRANscript QUantification In Long reads-anaLYZER), a flexible, architecture-aware deep learning framework for processing long-read single-cell RNA-seq data. Tranquillyzer employs a hybrid neural network architecture and a global, context-aware design, and enables precise identification of structural elements - even when elements are shifted, partially degraded, or repeated due to sequencing noise or library construction variability. In addition to supporting established single-cell protocols, Tranquillyzer accommodates custom library formats through rapid, one-time model training on user-defined label schemas, typically completed within a few hours on standard GPUs. Additional features such as scalability across large datasets and comprehensive visualization capabilities further position Tranquillyzer as a flexible and scalable framework solution for processing long-read single-cell transcriptomic datasets.

bioinformatics↗

Brain-derived extracellular vesicle microRNAs in Lewy body and Alzheimer's disease

INTRODUCTIONRobust plasma-based biomarkers to distinguish Lewy body disease (LBD) and Alzheimers disease (AD) are currently lacking. We applied track-etch magnetic nanopore (TENPO) sorting for enrichment of brain-derived extracellular vesicle (EV) signatures as potential biomarkers to address this gap. METHODSWe analyzed plasma from 137 autopsy-confirmed patients [30 LBD, 31 AD, 30 AD/LBD, 19 AD with amygdala Lewy bodies (AD/ALB), and 27 controls], sequencing miRNAs from TENPO-isolated GluR2-positive (neuron-enriched) and GLAST-positive (astrocyte-enriched) EVs, and measuring plasma proteins (A{beta}40, A{beta}42, tau, p-Tau181, p-Tau231) via SIMOA. RESULTSWe identified 16 GluR2+, 8 GLAST+, and 4 protein biomarkers with differential expression (false discovery rate-corrected P value < .1) between LBD and AD. A multimodal 15-feature panel classified LBD versus AD with 10-fold cross-validated accuracy = 0.95 and area under the curve (AUC) = 0.96. DISCUSSIONBrain-derived EVs offer accurate and accessible miRNA biomarkers for the differential diagnosis of LBD and AD.

bioengineering↗