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Biology subjects

Liu, X.

Publications and source records attributed to Liu, X..

At least 19 recordsLinked to original sources

Brain state locks silent memories in a trained fly connectome

Complete connectomes now exist for insect nervous systems, but whether a fixed wiring diagram can learn, and what its memories consist of, is unknown. Here, we trained a spiking model of the whole male Drosophila central nervous system, 167,106 neurons with fixed wiring, to plan moves and to remember a visual cue. Spikes write the cue into neuronal adaptation, which holds it silently until the next input reads it out. Cells that hold the trace are enriched for transcripts of a calcium-activated potassium channel in fly cell atlases. The learned readout recalls the trace only in the brain state of learning: the same trace evokes a different response at another delay, and a disease-like loss of potassium current rewrites the trace and changes how it is read. Learning in the new state is spared. Memory failure can arise from a change of state rather than a loss of storage.

neuroscience↗

Stabilizing gas in aqueous liquids with metal-organic frameworks for persistent acoustic transduction

Gas is the most efficient mediator of acoustic energy owing to its high compressibility, yet its thermodynamic instability in aqueous environments makes it inherently transient, limiting sustained ultrasound-biological interfacing. Here, we show that gas can be stabilized, confined, and manipulated in the liquid phase to function as a persistent acoustic transducer. By trapping gas within designed microporous metal-organic framework (MOF) nanocrystals, interfacial forces establish a stable ternary-phase equilibrium that suppresses water intrusion and prevents gas collapse, enabling reversible, non-destructive oscillations under ultrasound stimulation and providing design principles for stabilizing gas in liquid environments. By leveraging high-resolution ultra-high-speed digital image correlation (DIC), we unveil the previously inaccessible spatiotemporal dynamics of confined gas oscillations within these nanotransducers under ultrasound stimulation, revealing localized amplification of the surrounding acoustic field and establishing a quantitative structure-function relationship for programmable acoustic transduction. These aqueous-phase gas nanotransducers exhibit sustained acoustic amplification over millions of excitation cycles and remain functional after prolonged storage (>2 years) under physiological conditions. In vitro and in vivo, this platform enables long-term ultrasound imaging and sustained, non-invasive neuromodulation by converting confined gas oscillations into persistent and amplified mechanical actuation. Our findings establish a generalizable design framework for stabilizing gas in liquid environments to achieve persistent and programmable acoustic transduction, thereby enabling sustained ultrasound-biological interfacing and opening opportunities for gas-based therapeutics.

bioengineering↗

Glioblastoma Hijacks Astrocyte Ribosomes to Feul Malignancy through Translatome Reprogramming

Cancer cells demand elevated protein synthesis, yet whether they directly requisition ribosomes from microenvironmental host cells remains unknown. Here, utilizing in vivo and in vitro ribosome tracing, we show that glioblastoma (GBM) cells hijack ribosomes from surrounding astrocytes via tunneling nanotube-like structures. This transfer supports GBM malignancy in both murine and patient derived models. Single cell RNA sequencing along with whole cell and cell source traceable ribosome profiling reveal that transferred ribosomes are translationally active and selectively reprogram the tumor translatome, prioritizing cell-cycle genes and driving interferon-response-mediated immune evasion. Through a genome wide CRISPR screen, we identify INTS12 as a critical mediator of ribosome transfer. Genetic inactivation or AAV-mediated knockdown of INTS12 impairs ribosome uptake, curbs translation and proliferation, remodels the immunosuppressive landscape, and extends survival in orthotopic models. Our study uncovers a parasitic translation-support mechanism in GBM, establishing INTS12 as a therapeutic vulnerability to disrupt ribosome transfer.

cancer biology↗

Lineage-mixed neurodevelopmental programs in pediatric sarcomas nominate tumor-selective surface antigen pairs.

Pediatric solid tumors have low mutational burden, frequent oncogenic gene fusions, and developmental origins in arrested progenitor cells. Single-cell RNA-seq (scRNA-seq) could represent an ideal tool to assess whether these convergent biological features yield shared therapeutic vulnerabilities. However, while existing tools can extract gene expression programs for pan-tumor single-cell data, interpreting them requires domain expertise across many disciplines and diseases. Here, we analyzed a pan-pediatric scRNA-seq atlas of 266 patient- and xenograft-derived samples across 22 pediatric solid tumor types. To address the bottleneck between gene program identification and interpretation, we developed an AI agent framework built on off-the-shelf large language models (e.g., Gemini 2.5) to interpret gene expression programs at the level of human experts, but at much greater scale and speed. Our agent identified ectopic expression of neuronal marker genes as a unique feature of several fusion-driven sarcomas. This gene expression pattern resulted in tumor-specific co-expression of mixed mesenchymal/neuronal surface markers, providing a plausible therapeutic window to target these tumor types using emerging AND-gated therapeutic strategies, such as bispecific antibody-drug conjugates (ADCs) and bispecific CAR-T cells. As proof of principle, we nominated and validated STEAP1/NPTXR as a Ewing sarcoma candidate cell surface target pair. Together, this work delivers a pan-pediatric solid tumor scRNA-seq atlas, establishes a generalizable and accessible AI-based framework that complements existing single-cell methods by automating interpretation of pan-disease single-cell atlases, and nominates new bispecific ADC/CAR-T targets for catastrophic pediatric cancers.

cancer biology↗

Multi-resolution humanness scoring of antibodies via a region-isolated language model

Antibodies recognized as foreign can elicit anti-drug antibodies that compromise efficacy and safety, making humanness scoring, estimating how human-like a sequence appears, an early, repeated step in antibody development. Widely used scores reduce a variable domain to a single framework-dominated number, leaving the complementarity-determining regions (CDRs) grafted during humanization, diversified by generative models weakly supervised and rarely audited. Here we introduce IgScope, a 23-million-parameter antibody language model trained from scratch that scores humanness at chain, IMGT-region, and residue resolution; a region-isolated attention module confines attention to within-region pairs, and chimeric-sequence training supplies region-level supervision. On 2.38 million held-out chains, masking all framework tokens leaves CDR accuracy unchanged, and back-mutated murine residues in human frameworks are detected at 93.4% accuracy. At chain level, IgScope matches the strongest published correlation with clinical anti-drug-antibody incidence (r = 0.567, n = 217) and outperforms a same-protocol recomputation. Region-level scoring exposes what chain-level scoring conceals: antibodies designed de novo by four generative models pass whole-chain humanness (0.966-0.988), while their CDRs score far below natural (P < 1e-30) in every chain class. Quality control turns the same resolution to the mirror-image question: in humanized-mouse platforms, whose domains are human by design, IgScope scores the domain as human and, in HUGO-Nano chimeric VHHs, isolates only the FR2 signal of four camelid hallmark residues deliberately retained to stabilize the VHH. IgScope gives antibody humanization a verified foundation and generative design an audit.

bioinformatics↗

Efficient recovery of transgene-free edited tobacco using the transgene self-elimination system via de novo regeneration

Elimination of integrated editing constructs remains a major challenge for generating transgene-free progeny in plant genome editing based on Agrobacterium-mediated regeneration. Here, we adapted the Transgene Killer CRISPR (TKC) concept to tobacco and established the transgene self-elimination system, in which CRISPR/Cas9 is coupled with developmentally regulated BARNASE cassettes. Three pU3TR-derived vectors carrying DLL-, OsRP3- or PHAS-driven Barnase regenerated normally after leaf-disc transformation. The DLL construct pEB138 showed the highest T editing frequency, with 56 of 69 independent T plants (81.16%) carrying mutations at one or both NtDFR target loci. Under a stringent lineage-level screen in which up to 48 T progeny were tested per T line, 36 of 43 pEB138 lineages (83.72%) yielded uniformly marker-negative progeny for the three assayed T-DNA markers, compared with 0 of 7 lineages transformed with the parental pU3TR vector. The platform also supported recovery of dfr mutants with altered flower pigmentation and NtA622-edited lines with reduced nicotine accumulation. Moreover, introduction of DLL-iBarnase into the independent pDC45 editing backbone did not impair shoot regeneration, and representative NtBBL progeny showed markedly reduced nicotine content together with loss of the selectable cassette. These results demonstrate that BARNASE-assisted transgene elimination can be integrated with Agrobacterium-mediated de novo regeneration in a dicot, enabling one-step recovery of transgene-free edited tobacco progeny.

molecular biology↗

OTTER: Orchestrated Transcriptomic, Tumor-xenograft (PDX/CDX), and Epigenomic Reporting Workflow

Summary: Tumor xenograft sequencing libraries inevitably contain infiltrating murine host reads, but conventional deconvolution tools fail on bisulfite sequencing (BS-seq) because chemical C-to-T deamination collapses sequence entropy and destroys graft recall (< 0.015%). We present OTTER, an automated, compiled multi-omics workflow framework that decouples execution into static domain operators, an immutable reference registry, and a native strand-aware edit-distance engine, restoring bisulfite deconvolution (52%-54% recall across a 0%-99% compositional gradient) while preserving complete decision parity on transcriptomics. Availability and implementation: OTTER is implemented in Go and Rust, runs on x86_64 Linux (including CentOS 7 with glibc 2.17), and is freely available open-source under the MIT License at https://github.com/otterlab-bio/otter; test and validation data are provided at https://huggingface.co/datasets/fallingstar10/otter-data.

bioinformatics↗

Habitual sleep duration is associated with the cortical organisation of brain network controllability

Sleep is fundamental to adaptive brain function, yet how habitual sleep relates to the structural network properties that support flexible transitions between brain states remains poorly understood. Combining wrist-accelerometer sleep measures with diffusion MRI connectomes from 15,799 UK Biobank adults, we show that longer workday sleep is associated with higher modal controllability of somatomotor systems and lower controllability of visual cortex. This system-specific signature reproduced in a locked test set (n = 4,740) and was robust across extensive sensitivity analyses. Decomposition showed that it reflects a redistribution of structural connection weight, with greater absolute visual connectivity and a smaller somatomotor share of the whole-brain total. Weekend catch-up sleep showed no comparable association. The signature was distinct from brain-ageing patterns and, across 1,226 phenotypes, related mainly to physical activity and body composition rather than cognition. These findings link everyday sleep habits to the system-specific organisation of brain network controllability.

neuroscience↗

Crystalline silica exposure causes latent biomechanical abnormalities along the cardiopulmonary axis

Rationale Crystalline silica exposure is a major global health burden linked to chronic lung disease and cardiopulmonary morbidity, but early lung-vascular-cardiac abnormalities preceding overt functional decline are poorly defined. Objectives To determine whether a single crystalline silica exposure produces subclinical abnormalities across the integrated axis of cardiopulmonary response (lung[->]pulmonary artery[->]right ventricle) and identify associated sex-dependent physiologic patterns and molecular programs. Methods Male and female mice received a single endotracheal instillation of crystalline silica or vehicle (saline). At 28 days, assessments included voluntary wheel running, diffusion capacity, pulmonary function testing, bronchoalveolar lavage analysis, lung histology and electron microscopy, ex vivo proximal pulmonary artery biomechanics and microstructural second harmonic generation imaging, right ventricular pressure, transthoracic echocardiography, and bulk RNA sequencing of lung and right ventricle. Results Despite recovery of body weight and preserved voluntary exercise, silica-exposed mice demonstrated reduced diffusion capacity, ultrastructural thickening, and disruption of the alveolar-capillary barrier. Bronchoalveolar lavage revealed persistent inflammation with elevated macrophages, lymphocytes, neutrophils, and protein, alongside retained particulate and surfactant-rich debris (silicoproteinosis). Lung mechanics were sex-dependent; females showed a parenchymal-dominant phenotype and males showed increased airway resistance. Elevated pulmonary circulatory pressures caused increased functional stiffness and reduced distensibility of the proximal pulmonary arteries. Right ventricular free wall thickening was noted in females. Lung transcriptomics indicated persistent immune activation and extracellular matrix remodeling, while the right ventricle demonstrated metabolic reprogramming with downregulation of structural and reparative programs. Conclusions A single crystalline silica exposure induces a subclinical, multi-compartment cardiopulmonary phenotype characterized by persistent alveolar-capillary injury, pulmonary vascular stiffening, increased right ventricular afterload, sex-dependent pulmonary mechanics, and divergent organ-level transcriptomic responses.

physiology↗

FapA extends the flagellar cage-dependent network into the cytoplasm to control surface-associated behaviors in Helicobacter pylori

Flagellar systems enable many host-associated bacteria to colonize successfully. One such pathogen is Helicobacter pylori, which assembles an elaborate, high-torque flagellar motor that has a wide C-ring, 18 stator complexes, and is surrounded by a cage that includes homologs of the type IV pilus proteins PilM, PilN, and PilO. PilMNO act to repress soft-agar migration while promoting cell aggregation, microcolony, and biofilm formation, but the pathway linking the flagellar cage to these behaviors is unknown. Here we identify FapA, a member of the flagellar assembly protein A (FapA) family, as a component of this pathway. Deletion of fapA increased soft-agar migration and reduced microcolony and biofilm formation, similar to deletion of pilMNO. Epistasis analysis placed FapA downstream of the PilMNO flagellar cage. Using fluorescent fusions and protein-protein interaction experiments, FapA was found to localize to the cell poles, the sites of flagellar motor placement, and interact with the cytoplasmic PilM component of the cage. Indeed, cryo-electron tomography experiments detected cytoplasmic density near PilM that was lost in the {Delta}fapA deletion mutant. Phylogenetic analysis suggests that FapA proteins are more widespread than previously appreciated, being found in multiple bacterial phyla including Campylobacterota, Bacillota, Spirochaetota, Desulfobacterota, Thermotogota, Synergistota, and Pseudomonadota. Together, these findings support that the H. pylori flagellar cage has additional components that reside in the cytoplasm but similarly function to limit motility and activate a sessile/biofilm lifestyle. Given the widespread nature of FapA, our results suggest that many other bacteria might employ FapA homologs for similar purposes.

microbiology↗

AI-guided discovery of natural pocket proteins for portable small-molecule sensing

Recognition-element development remains an important practical challenge in small-molecule biosensing. Here, we present DWCLASS, an AI-guided workflow that combines screening of natural pocket proteins, molecular dynamics simulations, experimental binding assessment, and portable metasurface plasmonic sensing. Using thiamine (vitamin B1, thiamine) and 25-hydroxyvitamin D3 [25(OH)D3] as model analytes, the workflow identified binding responses in 7 of 16 tested analyte-protein pairs (43.8%). Selected proteins were incorporated into a competitive MetaSPR assay with gold nanoparticle amplification and acoustic mixing. The portable device provided a 240 s measurement step for prepared samples. Serum LODs were 2.98 ppt for thiamine and 3.82 ppt for 25(OH)D. Preliminary measurements of human serum specimens were compared with commercial ELISA to explore performance in biological samples. This study establishes an integrated route from AI-assisted screening of natural proteins to portable assay development for two chemically distinct vitamin analytes. Applicability to additional targets and clinical reference accuracy remain to be established.

bioinformatics↗

Root gene regulatory network analysis reveals roles for defense hormones and secondary metabolites in establishment of disease-suppressive soil

Plants recruit beneficial microbiota in their rhizosphere to alleviate stresses. In Arabidopsis thaliana, foliar infection by Hyaloperonospora arabidopsidis (Hpa) has been shown to establish a disease-suppressive microbiome that promotes protection against Hpa infection of the subsequent plant generation grown in this conditioned soil - a phenomenon known as soil-borne legacy (SBL). The root responses involved in SBL establishment have remained largely unclear. In this study, time-series RNA-seq of roots from Hpa-infected plants grown in natural soil was conducted over seven days post-inoculation. A gene regulatory network of the responding roots was constructed. The role of predicted key components was verified in follow-up assays. Root transcriptional reprogramming started within one day after foliar infection. Genes associated with salicylic acid (SA)-mediated defense were upregulated, while those linked to secondary metabolism and jasmonic acid (JA) responsiveness were downregulated. SA accumulation increased at 1 dpi, and JA decreased by 3 dpi. Transcriptional regulation occurred primarily in the tips of the roots. Mutant analyses confirmed that SA, JA, indole glucosinolates, camalexin, and flavonoids contribute to SBL establishment. Our findings reveal rapid systemic transcriptional reprogramming in roots upon foliar pathogen attack, uncovering novel roles of hormone signaling and secondary metabolism in shaping a disease-suppressive soil beyond their known defense functions.

plant biology↗

RiboDFM: Robust RNA sequence design using backbone-conditioned discrete flow matching

Designing RNA sequences that fold into predefined 3D structures is central to RNA engineering, yet it remains challenging due to the scarcity of experimentally determined structures and the complex sequence-structure relationships. Here, we present RiboDFM, a backbone-conditioned discrete flow-matching framework for RNA sequence design. RiboDFM progressively resolves fully masked sequences by integrating a geometric backbone encoder, an auxiliary base-pairing prediction head, and language model representations into a discrete flow sampler. To expand our training data, we supplemented experimental structures with a large-scale collection of trRosettaRNA2-predicted models. Across diverse benchmarks, RiboDFM achieves high sequence recovery and generates sequences with greater tertiary-structure self-consistency than existing methods. RiboDFM also performs strongly on aptamer-focused design tasks. Finally, beyond sequence generation, the nucleotide probabilities derived from RiboDFM' s flow trajectory serve as an intrinsic measure of sequence-structure compatibility. This enables reliable confidence estimation for designed sequences, as well as reference-free, zero-shot assessment of predicted structure models. Together, these results establish RiboDFM as an effective framework for structure-based RNA sequence design.

bioinformatics↗

KRT7CreER Ferrets Enable Lineage Tracing of Ductal Epithelia and Pancreatic Remodeling

Keratin 7 (KRT7) is expressed in simple and ductal epithelia and is associated with epithelial plasticity during development, injury, and disease. However, the in vivo fate and regenerative behavior of KRT7 cells remain poorly defined because lineage-tracing models are lacking in species that closely recapitulate human disease. To address this gap, we generated KRT7CreER ferrets and crossed them with ROSAmTmG Cre-reporter ferrets, with or without the CFTRG551D/G551D mutation. Following tamoxifen induction, KRT7-derived EGFP cells were identified in glandular and ductal epithelia across multiple organs. Pulse-chase lineage tracing revealed that KRT7BSND cells turn over rapidly during salivary gland development. In the pancreas, KRT7 lineage-labeled cells are present at all levels of the ductal tree under homeostatic conditions. In cystic fibrosis (CF) ferrets, KRT7-derived centroacinar cells and intercalated ductal lineages persisted and underwent marked remodeling, characterized by expansion of the SOX9 centroacinar cell pod into intercalated ducts. Although acinar cells were not lineage-labeled in the healthy pancreas, EGFP/CELA3B cells emerged in the CF pancreas and in acinar-derived organoids, consistent with induction of KRT7 during acinar-to-ductal metaplasia. These findings establish KRT7CreER ferrets as a versatile model for studying ductal epithelial lineage dynamics, pancreatic remodeling, and epithelial plasticity in both homeostatic and pathological conditions.

pathology↗

Vascularized Organoids Emerge from a Heart-Foregut-like Intermediate Recapitulating Early Human Development

During early cardiogenesis, the heart regions lie in close contact with foregut endoderm, which supplies essential nutrients and signaling cues to orchestrate primitive heart tube assembly. Here, we show that self-organized heart/foregut like-structures emerge from human pluripotent stem cells (hPSCs). The initial heart/foregut-like structures, termed the Seed, are encased by surrounding supportive cells termed Soil, which provide a matrix microenvironment; the Seed progressively develops into chambered human cardiac organoids (hCOs) containing cardiomyocytes (CMs), epicardial cells, cardiac fibroblasts, and endothelial cells. Optimization of the induction system further enhanced hCO maturation and vascularization. Therefore, this Soil-Seed system provides a model to dissect human early heart/foregut self-organization.

developmental biology↗

Longitudinal diffusion tensor imaging identifies coordinated white matter remodeling during cocaine self-administration in mice

White matter microstructural alterations are increasingly recognized as a feature of cocaine use disorder (CUD), yet the longitudinal progression and biological underpinnings of these changes remain poorly understood. Although rodent intravenous self-administration (IVSA) provides a translational model of voluntary cocaine use, longitudinal diffusion tensor imaging (DTI) has not previously been combined with cocaine IVSA in mice. Here, we established a longitudinal IVSA-DTI framework to characterize white matter microstructural remodeling during cocaine self-administration and early withdrawal. Male C57BL/6 mice underwent DTI at baseline, following 11 consecutive days of cocaine (0.5 mg/kg/infusion) or saline IVSA, and after a 7-day withdrawal period immediately following a cocaine-seeking test (n = 4/group). Fractional anisotropy (FA) was evaluated longitudinally using atlas-based region-of-interest analyses and whole-brain diffusion maps. Cocaine-treated mice acquired robust operant responding and exhibited coordinated longitudinal FA alterations across interconnected hippocampal-associated white matter pathways. The most consistent changes occurred within the bilateral dorsal hippocampal commissure, fornix, and fimbria, with cocaine-treated mice demonstrating increased FA during self-administration relative to baseline while saline controls exhibited smaller or opposing longitudinal changes. Difference-in-differences maps further demonstrated cocaine-associated FA alterations within hippocampal pathways and localized regions of the corpus callosum after accounting for longitudinal changes in saline controls. These findings establish the feasibility of combining longitudinal DTI with cocaine IVSA in mice and demonstrate coordinated white matter microstructural remodeling during voluntary cocaine exposure. This framework provides a translational platform for future studies integrating longitudinal neuroimaging with genetically modified mouse models, tractography, and histological validation to investigate the mechanisms underlying cocaine-associated white matter plasticity.

neuroscience↗

KRT7 Marks an Airway Glandular Ductal Stem Cell Population That Supports Multilineage Development and Regeneration

Airway submucosal glands (SMGs) play a central role in host defense through mucus secretion, airway hydration, and mucociliary clearance. However, the hierarchical organization of glandular progenitor populations remains poorly defined, largely because SMGs are sparse and restricted to the proximal trachea in murine models. Using the ferret, a model that closely recapitulates the gland-rich submucosal architecture of human cartilaginous airways, we identify KRT7+ glandular ductal epithelial cells as a progenitor population. In both adult ferret and healthy human airways, KRT7 expression is primarily restricted to the SMG duct epithelium, where it is co-expressed with KRT19 and CD166 but only partially overlaps with ALDH1A1. During early postnatal development, KRT7 expression becomes progressively restricted to glandular ductal epithelium and is ultimately excluded from mature acinar, myoepithelial cells, and KRT5+/KRT14+ basal lineages. Fate mapping in KRT7CreER;ROSAmTmG transgenic ferrets revealed that KRT7-lineage cells serve as multipotent progenitors during SMG morphogenesis, generating both serous and mucous epithelial cells. Following severe airway injury, KRT7-lineage cells survive within gland ducts and rapidly expand to repair the damaged surface epithelium by differentiating into ciliated and secretory cells but not KRT5+ basal cells. In organoid cultures, glandular KRT7-lineage cells acquired a KRT5+ basal-like phenotype and generated multilineage epithelia with functional CFTR-mediated transport. These findings identify the KRT7+ ductal niche as a critical progenitor reservoir for airway development, homeostasis, and regeneration, with implications for cystic fibrosis therapies.

cell biology↗

NeuroPilot: Longitudinal intravital neural imaging across scales and modalities through an agentic platform

Longitudinal intravital imaging is essential for understanding how neural populations evolve across behavioral states, yet converting large-scale recordings into biological insight remains a fundamental challenge because neural signals are degraded by noise, non-rigid motion, and heterogeneous recording conditions. Here we introduce NeuroPilot, an agentic framework that transforms neural imaging analysis into a closed-loop, context-aware process, integrating a multimodal large language model with callable computational imaging modules to adaptively coordinate workflows from raw recordings to population-level readouts. Across heterogeneous imaging and experimental regimes, NeuroPilot restores motion-degraded recordings and supports consistent neural signal recovery, detection, and tracking in challenging deep-brain, freely moving, and longitudinal settings. These enable neuronal population tracking across spinal stimulation paradigms, deep-brain imaging, and continuous 24-hour mPFC recordings aligned with spontaneous sleep-wake behavior. By converting heterogeneous intravital recordings into stable population activity maps, NeuroPilot supports behavioral decoding and reveals structured neural dynamics across behavioral states and transitions. NeuroPilot establishes a scalable agentic paradigm for neural imaging analysis, expanding experimental access to the measurement, visualization, and interpretation of neural population activity.

neuroscience↗