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Biology subjects

Li, B.

Publications and source records attributed to Li, B..

At least 19 recordsLinked to original sources

Structural Evolution of Neural Networks during Zebrafish Early Development

The spatial architecture of neural networks underpins nervous system function, yet dynamic in vivo evidence for their early establishment process remains scarce. Here, using long-term confocal live-cell imaging of transgenic zebrafish, we dissected neural network development across the brain, yolk sac, and spinal cord at single-cell resolution. We reveal that repeated growth cone bifurcation is the fundamental cellular mechanism for network node formation. Despite distinct developmental origins, networks in all three regions exhibit highly conserved dynamics, strictly following Strahler hierarchical ordering and Hack's power-law scaling. Quantitative topological analysis shows that as development progresses, node numbers and clustering coefficients increase, while network density decreases. This reflects a structural optimization strategy balancing high functional efficiency with low wiring cost. These findings suggest that physical and geometric constraints, combined with simple local rules, drive the self-organization of complex neural networks, offering valuable principles for artificial network design.

neuroscience↗

Mesoscale Soft Robotics for Mechanically Perturbing and Functionally Monitoring Responses in Human Organoids

Human organoids represent promising models for studies of significance to the biology and medical communities. Of the existing approaches for monitoring organoids, none offers the ability to apply programmable mechanical forces while simultaneously recording multi-modal physiological responses, of relevance to phenomena spanning from traumatic brain injuries to cardiac rhythm disorders. Here, we present a mesoscale soft robotic organoid interface that enables programmable delivery of forces to organoids of diverse shapes, and to map electrophysiological activity and mechanical responses. The platform combines actuation elements with integrated sensors for quantitative measurement and control. Studies using this technology reveal that spheroidal cortical organoids exhibit distinct responses to mechanical trauma, including silencing, recovery, and changes in neuronal firing patterns. Additional experiments on cardiac ring tissues demonstrate that sustained stretching induces beat-to-beat rhythm variability and altered conduction. The results establish a framework for investigating force-triggered transitions between physiological and disease-like states in human tissue models.

bioengineering↗

Cancer cells hijack mitochondria from Bhlhe40+ T cells for immune evasion

Cancer cells hijack mitochondria from T cells via tunneling nanotubes (TNTs) to promote immune evasion, yet the underlying mechanisms of mitochondrial-loss remain poorly understood. Here, through targeted screening of relevant genes, we demonstrated that CD38 is a potent regulator of TNT formation through interaction with its cognate ligand, CD31. Conditional knockdown of Cd38 in murine models leads to CD8+ T cell-dependent tumor shrinkage. Single-cell RNA sequencing of tumor-infiltrating T cells revealed that cancer cells preferentially target the Bhlhe40+ effector subset. Bhlhe40 is a transcription factor that upregulates the expression of S100a4, a reported chemoattractant of nanotubes. Bhlhe40 upregulation creates mitochondrial-loss vulnerability for tumor neoantigen-specific T cells. Dual mitochondria transfer blockade with Cd38 knockdown and S100a4 inhibitor trifluoperazine markedly suppressed tumor growth. Collectively, our findings identified the Bhlhe40-S100a4 cascade as a critical regulator of cancer/T cell mitochondrial transfer, providing insights for the development of new cancer immunotherapies.

immunology↗

Oxidized TRX1 and DPP8/9 stabilize the MIA40-AIFM1 complex during intrinsic apoptosis

Mammalian cells execute diverse death programs with distinct immunological consequences. Mitochondrial outer membrane permeabilization (MOMP) drives typically immunologically silent intrinsic apoptosis by releasing cytochrome c and other proapoptotic proteins into the cytosol. Here, we show that MOMP also engages two established repressors of the pyroptosis-inducing NLRP1 inflammasome, oxidized thioredoxin-1 (oxTRX1) and catalytically active DPP8/9, in a coordinated redox and proteostasis program. Immediately after MOMP, oxTRX1 forms a disulfide with MIA40 Cys4 at the MIA40-AIFM1 interface. Subsequently, DPP8/9 cleave AK2, targeting this competing AIFM1 ligand for degradation. Biochemical reconstitution and cryo-EM reveal that oxTRX1 promotes AIFM1 dimerization and preferentially stabilizes MIA40-AIFM1 over AK2-AIFM1. Thus, redox-dependent complex assembly and selective proteolysis converge to favor MIA40-bound AIFM1 after MOMP. These findings suggest how post-MOMP remodeling could reinforce NLRP1 restraint during apoptosis and how disruption of this program could trigger pyroptosis.

cell biology↗

Excluded Volume Effect-induced Shrinkage for Resolution Enhancement of Hydrogel Bioconstructs

Biofabrication of hydrogel materials is usually constrained by process-specific resolution limits. Here, we introduce excluded volume effect-induced shrinkage (EVER), a dehydration-enabled resolution enhancement strategy that achieves dimensional refinement via post-processing. In this approach, we treat biofabricated constructs with hydrophilic macromolecular crowding agent bath, with poloxamer as a representative. With EVER treatment, gelatin-based constructs can reach a dimension reduction of up to ~49% with an estimated volumetric reduction of ~87%. Shape fidelity was well retained after shrinkage across different constructs and could be stabilized by introducing secondary crosslinking. In extrusion bioprinted cell-laden constructs, myoblasts retained a considerable cell viability right after the shrinkage treatment and recovered significantly by day 1, with subsequent cell spreading and increasing proliferation over 7 days. Without the need of continued immersion in the shrinkage bath, EVER provides a hardware-independent route for refining hydrogel structures while retaining encapsulated cell compatibility.

bioengineering↗

BLOOM: Biologically Informed Flow Matching for Transcriptomic Virtual Embryo Modeling

Constructing a virtual embryo requires a generative representation of how heterogeneous cell populations change across developmental time. Here we introduce BLOOM, a biologically informed framework for conditional generation of developmental cell populations. BLOOM integrates temporal population context with developmental and regulatory priors through conditional flow matching to generate cell-expression distributions at queried stages in either temporal direction. Evaluation spans three mouse single-cell atlases covering prenatal development, visual-cortex maturation and multi-organ endothelial specialization. In comparisons with 22 time-series forecasting baselines, BLOOM ranks first for gene- and cell-expression correlations across all three datasets. Measured-stage evaluations support recovery of developmental expression patterns, population organization and marker-specific temporal relationships. Biological analyses connect these predictions to cell-state identities, gene programmes and regulatory associations. At unmeasured stages, interpolation and autoregressive history and future rollouts extend simulated expression dynamics between and beyond measured timepoints. Analyses of marker genes and temporal descriptors identify candidate differences in the timing of muscle-associated, neural and vascular-specialization programmes. Input-based gene perturbations further probe predicted responses of edited genes and associated molecular programmes across time. Together, BLOOM supports transcriptomic virtual embryo modeling by bridging temporal sampling gaps, exploring extended developmental trajectories and prioritizing gene-dependent hypotheses for experimental investigation.

bioinformatics↗

Deletion of LRP1 in Smooth Muscle Cells Induces Infrarenal Aortic Aneurysms in Mice

Background: Low-density lipoprotein receptor-related protein 1 (LRP1) in smooth muscle cells (SMCs) is essential for maintaining aortic wall integrity. This study investigated whether deletion of LRP1 in SMCs induces region-specific aortic pathology and evaluated a potential therapeutic strategy. Methods: Lrp1-floxed mice were bred with Sm22-Cre+/0 mice to generate mice with SMC-LRP1 deletion (SMC-LRP1-/-) and wild-type littermates (SMC-LRP1+/+). Micro-computed tomography (micro-CT) was used to visualize the aorta, and aortic tissue sections were characterized histologically. To evaluate a potential therapeutic strategy, antisense oligonucleotides (ASOs) targeting hepatocyte-derived angiotensinogen (AGT) were administered to inhibit AGT synthesis. Results: Immunostaining and Western blotting confirmed LRP1 deletion in aortic SMCs. At 40 weeks of age, micro-CT revealed marked increases in aortic width and volume. Although dilatation occurred throughout the aorta, the infrarenal region exhibited the greatest expansion in both male and female SMC-LRP1-/- mice compared with SMC-LRP1+/+ littermates; subsequent analyses therefore focused on this region. LRP1 deletion in SMCs caused pronounced SMC loss and increased collagen deposition in the infrarenal aorta. Inhibition of hepatocyte-derived AGT with ASO attenuated infrarenal aortic dilatation and preserved aortic wall integrity in both male and female mice. Conclusions: Deletion of LRP1 in SMCs causes progressive aortic dilatation that includes the infrarenal aorta. Pharmacologic inhibition of hepatocyte-derived AGT attenuates infrarenal aortic dilatation.

pathology↗

Effects of Alternating Polarity Frequency on the Assembly of Electro-Methanogenic Microbial Communities

Electro-methanogenesis can enhance methane production and has attracted extensive interest, but the current strategies for building electro-methanogenic microbial communities suffer from several limitations. Alternating polarity has been shown as a new strategy to build electro-methanogenic communities, but the impact of alternation frequency on community assembly remains to be understood. In this study, the impact was evaluated using bioelectrochemical systems amended with granular activated carbon, and the working-electrode potential was alternated between +0.4 and -0.4 V vs. SHE at six frequencies ranging from 0.5 to 12 days. Among the tested conditions, 4-d alternation led to the best overall performance, producing approximately 250 L/L/kg cumulative biogas, 96% methane content, and a 45% methane yield, while preserving a stable and reproducible community structure. The community contained two Methanobacterium populations, two putatively electroactive Geobacter populations, and one putatively electroactive Pseudomonas population, together with diverse fermentative and syntrophic bacteria. Transcript-based analyses revealed clear frequency- and potential-dependent shifts in the activity of these functional groups. Redundancy analysis associated the Methanobacterium formicicum-related population with cathodic current and methane production, whereas the Geobacter sulfurreducens-related population was linked to anodic current and methane production. Bayesian and local-similarity networks further connected methanogen dynamics with specific electroactive, fermentative, and syntrophic partners. Collectively, these results establish alternating polarity frequency as a critical parameter for building robust communities capable of high-rate, high-quality methane production.

microbiology↗

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↗

Antigen-aware TCR embeddings reveal conserved immune patterns for personalized immune monitoring

T cell receptor (TCR) repertoires are highly individualized, while technical variation further complicates comparisons across individuals and cohorts. Here, we present TCRmeta, an antigen-aware framework that integrates population-scale repertoire relationships with experimentally defined antigen specificity to establish a shared space for repertoire analysis. TCRmeta predicted mutation-induced changes and captured antigen-related relationships in TCR specificity. Despite extensive sequence diversity, TCRmeta revealed a conserved repertoire landscape, enabling construction of a healthy reference for quantifying repertoire dispersal. Across cohorts, aging was associated with conserved V gene changes and progressive dispersal, with greater dispersal in CMV-positive individuals. Longitudinal analysis showed that repertoires progressively shifted toward the healthy reference following bone marrow transplantation or antiretroviral therapy. To directly compare repertoires in TCRmeta space, we developed Energy Shift, a pairwise measure robust to technical variation and HLA background while remaining sensitive to biological differences. Together, TCRmeta enables quantitative cross-individual and longitudinal immune monitoring.

bioinformatics↗

Longitudinal Metaproteomic and Lysine Crotonylation Remodeling Defines Clinical Response to Fecal Microbiota Transplantation in Ulcerative Colitis

Background Fecal microbiota transplantation (FMT) can induce steroid-free clinical remission in a subset of patients with ulcerative colitis (UC), but treatment responses remain heterogeneous and are not fully explained by taxonomic microbiome shifts. To define functional molecular features associated with FMT efficacy, we performed integrated longitudinal fecal metaproteomic and lysine crotonylation (Kcr) profiling. Methods We analyzed 87 fecal samples from 23 patients with active UC collected at baseline and at weeks 1, 8, and 12 after FMT. Patients were classified as responders (n = 13) or non-responders (n = 10) according to steroid-free clinical remission at week 12. Across samples, we identified an average of 3,682 proteins and 562 Kcr sites per sample. Results Responders showed greater metaproteomic and meta-crotonylomic complexity at week 12, sustained enrichment of Prevotella and Faecalibacterium, and eight directionally consistent baseline-altered proteins with candidate prognostic value. After FMT, responders exhibited coordinated microbial functional remodeling, including increased proteins involved in short-chain fatty acid (SCFA) metabolism, acyl-CoA-centered pathways, nutrient transport, and polysaccharide degradation, together with attenuation of host neutrophil-related inflammatory protein and Kcr signatures. Non-responders showed minimal or opposing molecular changes. Conclusions: These findings nominate longitudinal fecal metaproteomic and Kcr remodeling as functional molecular readouts of clinical response to FMT in UC and highlight lysine crotonylation as an underexplored metabolite-sensitive layer linking microbial metabolic restoration with host inflammatory resolution.

microbiology↗

Protruding Geometry Provides Potential Homing Sites of Circulating Tumor Cells

Circulating tumor cells (CTCs) must adhere to the vascular endothelium to initiate metastasis, yet the role of vessel wall topography remains unclear. We present an integrated microfluidic platform combining defined protruding geometries, live cell imaging, and controlled perfusion to study CTC homing. Using a multiscale device that reproduces hierarchical vascular branching, we show that CTCs accumulate preferentially at locations with protruded geometry, including bifurcations, sharp corners and positively curved segments. At these hotspots, a viscoelastic, polymer-like network assembles, capturing CTCs and accompanying progressive multicellular aggregation. This network undergoes stretching and elastic recoil even under laminar flow. Mechanistically, knockdown of DSG2 and ITGB3 reduces retention, suggesting a potential anti metastasis strategy targeting molecular mechanical coupling. Computational fluid dynamics simulations indicate that hotspots coincide with pronounced velocity and pressure perturbations. Our experiments identify local geometry as a critical determinant of CTC arrest and provide a platform for studying the physical mechanisms of metastatic homing.

cancer biology↗

Keratinocyte FABP5 mediates saturated fat-induced MAPK/CCL20 signaling in psoriatic inflammation

Saturated fats in high-fat diets (HFDs) have been associated with increased risk and severity of psoriasis. However, the underlying cellular and molecular mechanisms remain to be further defined. Here, using a unique mouse strain with keratinocyte-specific deletion of fatty acid-binding protein 5 (FABP5) (Fabp5f/fKrt6a-Cre), we reported that keratinocyte FABP5 deletion significantly attenuated saturated HFD-exacerbated psoriatic symptoms. Immunological analyses demonstrated that FABP5 specific deletion in keratinocytes selectively reduced skin TCR {gamma} {delta} dim cell accumulation and IL-17A production. Further skin bulk-RNA and single-cell RNA sequence analyses showed a strong association of keratinocyte FABP5 with increased activation of mitogen-activated protein kinase (MAPK) pathways under saturated HFD-induced obesity. Mechanistically, saturated fatty-acids (SFAs) induce FABP5-dependent MAPK activation and CCL20 production in keratinocytes, promoting the recruitment and activation of IL-17-producing {gamma}{delta} T cells in the skin. Together, these findings suggest a previously undefined FABP5/MAPK/CCL20 signaling axis that links saturated fats to exacerbated psoriatic inflammation.

immunology↗

FLASH X-rays preserve neutrophil chromatin to boost antitumor immunity

Ultrahigh dose-rate FLASH radiotherapy spares normal tissue while preserving antitumor activity, positioning it as a promising technology in radiation oncology, but its immunomodulatory mechanisms remain elusive. Here, using a bilateral subcutaneous tumor model in mice, we show that 8-Gy FLASH X-rays, versus an equal dose of conventional dose-rate (CONV) X-rays, elicit a robust abscopal antitumor effect with anti-PD-1 therapy. Single-cell transcriptome and T cell receptor (TCR) profiling reveal that FLASH X-rays plus anti-PD-1 enhance antitumor immune infiltration and TCR clonal expansion in both irradiated and abscopal tumor lesions. Mechanistically, the ultrashort temporal continuity of FLASH dose delivery conserves chromatin compaction in neutrophils during exposure and inhibits neutrophil extracellular trap (NET) formation, thereby dismantling NET-mediated CD8+ T-cell exclusion within primary tumors. Conversely, CONV or split-dose FLASH X-rays induce marked chromatin modifications prior to dose completion, leading to chromatin hyper-relaxation which promotes NETosis and consequently abrogates systemic antitumor immunity. Notably, this detrimental effect can be reversed by pharmacologically suppressing PARylation-mediated chromatin modification and decondensation in neutrophils. These findings identify radiation-induced aberrant chromatin relaxation in neutrophils as a critical determinant of radioimmunotherapy outcomes, providing a rationale for redefining the FLASH effect and advancing its clinical translation.

cancer biology↗

Transient tubular membrane injury is converted into persistent fibrosis through a macrophage-fibroblast relay

A central unresolved problem in acute kidney injury (AKI) is how a transient epithelial insult is converted into persistent fibrotic repair that drives progression toward chronic kidney disease. Although tubular, immune and stromal responses are individually well recognized, the mechanistically continuous relay linking these three compartments has remained unresolved. Here we define a directional information-conversion pathway spanning injured tubular epithelial cells, macrophages and fibroblasts. Time-resolved single-cell profiling identified a TREM2/SPP1 macrophage state that emerged as post-ischemic repair became fibrotic. Tubular injury remodeled phosphatidylserine (PS) species, increased oxidized PS and PS externalization, and generated a membrane-lipid context for TREM2 sensing, supported by PS masking, defined liposomes and orthogonal binding assays. Structure-function analysis separated R47-dependent phospholipid recognition from K183-dependent DAP12 coupling, linking membrane damage to SYK activation and NF-kB/AP-1-driven Spp1 transcription. Macrophage-derived SPP1 then activated ITGAV/ITGB1-associated FAK-SMAD2/3 signaling, fibroblast contraction and matrix production. Crucially, repair-phase SPP1 neutralization and post-injury Cx3cr1-lineage Trem2 deletion attenuated fibrosis, with delayed Trem2 deletion protective in both ischemic and obstructive injury. Human single-cell, spatial, urinary and tissue analyses showed cross-species and cross-scale convergence. These findings resolve how transient tubular membrane damage is successively transformed across three cellular compartments into persistent, yet interruptible, fibrotic repair.

pathology↗

Harnessing historical collections to reconstruct the invasion history of Microstegium vimineum (Poaceae)

The evolutionary processes underlying successful invasions are often difficult to disentangle. Historical collections provide a temporal perspective, offering great potential to reconstruct invasion histories and identify the processes driving invasions. Japanese stiltgrass (Microstegium vimineum) is an invasive C4 grass introduced to eastern North America over a century ago and now established in 31 USA states. To reconstruct its invasion history, we leveraged low-coverage whole-genome sequencing of 142 herbarium and 330 contemporary samples spanning the temporal and spatial extent of the North American invasion and the native range in Asia. We identified three independent introductions in the USA: an awnless form in the South and two independent introductions of awned forms in the North, with limited admixture among introductions across space and time. In both regions, we observed high genetic diversity in the earliest available collections despite demographic bottlenecks and identified several putative selective sweeps in or near flowering-time genes, suggesting rapid evolution in the introduced range. Our analyses support separate invasions in the USA, likely facilitated by standing genetic variation and selection, but provide little support for admixture playing a major role. Our study highlights the power of historical collections to uncover the processes and mechanisms underlying successful biological invasions.

evolutionary biology↗

When label-free morphology is sufficient for targeted cellular measurements

Label-free morphology captures cellular responses, but its ability to substitute for targeted cellular measurements depends on the intended use. We assess measurement sufficiency using nearly 10 million paired phase-reporter observations across 1,000 gene knockouts, 52 fluorescent reporters and 73 A549 screens. Ten predictors differed in recovery across held-out fields, genes and screens. Same-cell pairing controls identified reporter-state information beyond perturbation averages and measured covariates. Perturbation ranking often persisted despite reduced variation in predicted response magnitudes. Predictions of held-out knockout responses retained a median 79% of the strongest hits, whereas functional-term retention varied. Atlas-derived criteria identified 30 quantitative and 7 ranking proxies for a fixed ensemble, with reference reproducibility constraining interpretation. In independent primary-hepatocyte data, brightfield predictions prioritized 10 of the 11 compounds with the largest measured metabolic-activity losses among 217 held-out compounds. Measurement sufficiency therefore depends on target, predictor, context and scientific task, beyond predictive correlation alone.

bioinformatics↗

Agentic transcranial functional ultrasound imaging: @fUS

Functional ultrasound (fUS) imaging provides deep, wide-field access to brain function, but instrument cost and complex acquisition and analysis workflows restrict its wider adoption. Here we introduce @fUS, an agentic transcranial imaging platform with an open architecture that integrates purpose-built hardware with executable experimental skills and persistent structured memory. The system combines 128-channel, 16-bit acquisition at 125 MHz with GPU-based processing and enables functional imaging through the intact scalp and skull of mice, with approximately 100-m spatial resolution and 10-Hz temporal sampling, providing a basis for longitudinal studies without cranial-window surgery. Its agent connects scientific objectives to experimental design, direct instrument control and data analysis, retaining context across interactions and supporting inspectable workflows through text and hands-free voice control. Neuroscience trainees with limited engineering experience independently configured the system within 30 min. Agent-assisted exploration of whisker-stimulation datasets revealed low-frequency vascular changes beyond conventional response mapping, supported by complementary two-photon measurements of single-vessel diameter. By combining transcranial imaging with accessible instrument control and analysis, @fUS provides a foundation for wider adoption and larger, more diverse neuroscience datasets. More broadly, it offers a framework for scientific instruments in which measurement, computation and experimental reasoning are developed as parts of the same system.

bioengineering↗