Biology subjects

Xing, Y.

Publications and source records attributed to Xing, Y..

At least 19 recordsLinked to original sources

bioRxiv2026

Biosynthetic additive manufacturing through mycelium-bacteria consortia

Lignocellulosic biomass is the most abundant renewable raw material on Earth, yet its structural and carbon-storage potential remains unrealized: microbial decomposition returns stored carbon to the atmosphere before it can be harnessed as a durable material. Distinct microbial processes, such as biosynthesis and biomineralization, offer a natural counterpoint, converting organic carbon into mechanically robust, persistent materials such as polymers and minerals. Here, we establish a biosynthetic additive manufacturing strategy through mycelium-bacteria consortia, by coupling fungal self-assembly with bacterial biomineralization inside fabricated three-dimensional scaffolds derived from lignocellulosic biomass. Trametes versicolor forms a continuous living mycelial network that serves as both a structural template and a transport pathway, guiding the spatial colonization of Sporosarcina pasteurii and enabling volumetric calcium carbonate deposition throughout the scaffold interior, overcoming the surface-limited mineralization of conventional microbial systems. Integration with helicoidal Bouligand architectures translates microscale mineral reinforcement into macroscale performance, increasing compressive Young's modulus by 7-14-fold and ultimate strength by 5-fold relative to unmineralized conventional mycelium-based living composites. The living mycelial network also enables autonomous self-healing and modular self-assembly through hyphal bridging without external adhesives or energy input. This work establishes a scalable route for converting and upcycling transient biomass carbon into durable living structural materials for sustainable construction.

bioengineering↗

bioRxiv2026

Single-cell variant landscape of the human mitochondrial genome reveals cell type-specific functions and disease mechanisms

Mitochondrial DNA (mtDNA) heteroplasmy is a significant source of cellular genetic diversity and can cause disease yet its distribution and functional importance across different human cell types are poorly understood. Here we present scMOCHA (Single-Cell Mitochondrial Omics for Cellular Heteroplasmy Analysis), a scalable computational framework that resolves highconfidence, single-cell resolution mtDNA heteroplasmy directly from standard single-cell RNA sequencing (scRNA-seq) data. Using this tool to interrogate publicly available scRNA-seq datasets from human peripheral blood mononuclear cells (PBMC) and bone marrow (BM) uncovered the single-cell landscape of mtDNA single-nucleotide variants (SNVs) and heteroplasmy across ages in human hematopoietic cell types. PBMCs and BM share many inherited homoplasmic and highly heteroplasmic SNVs, whereas somatic SNVs are tissue- and cell type-specific and distributed across the mtDNA genome, suggesting that they arise largely stochastically. mtDNA replication error is a dominant force shaping homoplasmic variants, while oxidative stress potentially drives a significant portion of heteroplasmic and somatic mutations. Importantly, we discover previously unknown cell type-specific and human disease-associated mtDNA SNVs. By coupling mtDNA genotypes with matched single-cell nuclear transcriptomes and structural modeling, we uncover potential molecular mechanisms by which disease-associated mtDNA SNVs impact cellular processes such as inflammation and contribute to disease. Together, these findings define the single-cell variant landscape of the human mitochondrial genome and reveal previously unrecognized lineage- and disease-associated patterns of mtDNA variation in the human hematopoietic system.

genetics↗

bioRxiv2026

NSD2 deficiency disrupts the epigenetic landscape of cochlear hair cells to enhance ECM expression and to perturb cochlear hair cell function

Mammalian cochlear hair cells (HC) are crucial for hearing, and histone modifications may play an important role in HC maturation and functions. However, whether and how NSD2, a histone H3 lysine 36 (H3K36) dimethyltransferase, affects cochlear HC maturation remains unclear. Here, we established an HC-specific Nsd2 knockout mouse model and discovered that the loss of NSD2 results in severe structural defects in stereociliary bundles and profound hearing impairment. Integrated multi-omics profiling revealed that NSD2 deficiency leads to a decreased expression of H3K36me2, which in turn alters genome-wide chromatin accessibility and gene expression. Mechanistically, NSD2 deficiency triggers the aberrant upregulation of extracellular matrix (ECM) genes at the transcriptional level, causing excessive collagen accumulation and compromising tissue structure. Crucially, ECM intervention can mitigate NSD2-deficiency mediated hearing damage. Our study reveals an epigenetic mechanism by which NSD2 regulates cochlear HC maturation through inhibition of chromatin remodeling-induced ECM accumulation, and provides a potential new therapeutic direction for hearing impairment.

cell biology↗

bioRxiv2026

Brain organoid computing for robotic decision-making

Biomimicry has inspired the evolution of robotics toward greater autonomy, adaptability, and symbiosis with humans and dynamic environments. However, current robotic systems still face major challenges in recapitulating the high-efficiency decision-making capabilities of the human brain under complex and dynamic conditions. Here, we present Brainobot, a biohybrid robotic system that establishes a brain organoid controller as a high-level robotic decision-making layer for closed-loop embodiment. By leveraging brain organoid reservoir computing, Brainobot interacts with dynamic environments by receiving and processing sensory inputs and generating motor actions. As a proof-of-concept demonstration, Brainobot is implemented in a humanoid robotic system to perform real-world tasks, including object grasping and laser chasing. Interestingly, Brainobot exhibits unique features, including cross-task adaptivity, high computing efficiency, and low energy consumption. Thus, our approach may provide insights for advancing robotic embodiment and understanding biological decision-making.

bioengineering↗

bioRxiv2026

Transdermal diagnosis and therapy using an integrated acoustofluidic patch

Transdermal biosensing and drug delivery provide convenient, pain-free, and user-friendly solutions for personalized therapy. However, challenges remain in detecting and treating acute diseases, primarily due to current limitations in effective detection of transdermal biomarkers and administration of therapeutics to an individual within a short time window in a real-world environment. Here, we integrate a compact acoustofluidic patch for transdermal sampling, sensing, and delivery in a rapid and automated manner. By leveraging acoustic streaming and 3D-printed microfluidic designs, acoustofluidic sampler and injector modules are assembled for penetration of the skin stratum corneum, precise sampling of skin interstitial fluids, and controlled percutaneous release of therapeutics, respectively. By incorporating an electrochemical sensing module, the integrated patch can be further developed to achieve in situ and rapid detection of transdermal biomarkers and automated transdermal delivery of therapeutics via closed-loop control. As a proof-of-concept application, we demonstrate our approach can detect and reverse life-threatening acute allergic reactions in a mouse model of anaphylaxis by rapid sampling and sensing transdermal histamine followed by automated transdermal delivery of epinephrine. The innovative acoustofluidic patch may enable a new kind of transdermal devices for personalized therapy of various acute diseases.

bioengineering↗

bioRxiv2026

Information processing-like phenotype of human brain organoids

Human brain organoids recapitulate key physiological features and functions of the human brain and hold remarkable potential for studying neurological diseases. Despite clinical evidence suggesting that neurodegenerative diseases impair the information-processing ability of the human brain, the capacity of brain organoids for information processing and its relationship to neural network function remain largely unexplored. Here, we test and quantify information-processing-like properties of human cortical organoids using a task-based functional phenotyping framework (Brainopheno). We demonstrate the pattern-processing-like phenotype of cortical organoids through the representation and classification of evoked neural activities in response to distinct spatial input stimulation patterns via a microelectrode array (MEA) system. Moreover, this functional phenotype emerges with network maturation and is disrupted by pharmacological perturbations, linking classification performance to the functional integrity of organoid neural networks (ONNs). Importantly, this functional phenotype also reveals functional deficits in ONNs altered by a familial Alzheimer's disease (AD)-associated gene mutation (APP) and by monocytes from patients with sporadic AD. This work may establish a new quantifiable functional phenotype of neural organoids and provide a framework to bridge molecular and cellular profiles with neural circuit function for basic neurology, disease phenotyping, and therapeutic development.

bioengineering↗

bioRxiv2026

Unifying physical and molecular coordinate systems across modalities in spatial biology

Establishing a unified physical and molecular coordinate system from fragmented multi-modal data is a longstanding challenge in biology. Here, we present MAPS, a modality-agnostic platform for spatial biology comprising (1) MAPS-alignment for ultrafast alignment of any modality, (2) MAPS-integration for both anchored and unanchored integration across orthogonal modalities for 3D multi-modal reconstruction, and (3) MAPS-Explorer for large-scale interactive 3D analysis. MAPS outperformed existing methods across extensive benchmarks on 34 datasets spanning 16 technology platforms and 6 modalities, while delineating fine-grained multi-modal tissue architectures across diverse biological systems in mouse and human. At cross-consortium scale, MAPS integrated 434 slices comprising 21 million cells from 18 atlases and 5 modalities to construct the most comprehensive 3D multi-modal mouse brain atlas. At individual laboratory scale, MAPS empowered routine 2D spatial assays to reconstruct continuous 3D multi-modal landscapes of human hepatocellular carcinoma, revealing the limitations of 2D spatial relationships and uncovering depth-dependent immune-state transitions.

bioinformatics↗

bioRxiv2026

Paralemmin 2 is a shared, alternatively-spliced regulator of axon initial segments and paranodal junctions in oligodendrocytes

Nervous system function depends on highly specialized axonal membrane domains. For example, axon initial segments (AIS), nodes of Ranvier, and paranodal junctions are essential for action potential initia-tion and saltatory conduction. These domains use shared molecular machinery converging on the master scaffolding protein AnkyrinG (AnkG). Using endogenous AnkG-TurboID proximity proteomics, we identify Paralemmin 2 (Palm2), a previously uncharacterized CNS protein, as a shared component of the AIS and nodes of Ranvier in neurons, and paranodes in oligodendrocytes. Palm2 localizes transiently to the AIS and nodes during development, but is found at paranodes throughout life, reflecting cell type-specific splicing of a lipid-modified domain both necessary and sufficient for AnkG interaction. Mice lacking oli-godendroglial Palm2 assemble normal paranodes during development, but aged mice lose paranode in-tegrity due to loss of paranodal AnkG and Neurofascin-155. Our findings identify Palm2 as a lipid raft-associated regulator of axonal and oligodendroglial membrane domains and reveal cell type-specific pro-tein variants as a recurring principle for specializing axonal and glial membrane architectures.

neuroscience↗

bioRxiv2026

Progressive Loosening of a Dual Autoinhibitory Interface Activates PP2A-B56δ

Protein phosphatase 2A containing the B56{delta} regulatory subunit (PP2A-B56{delta}) is a critical signaling enzyme whose dysregulation is associated with cancer, neurodegenerative disorders, and Jordan's syndrome, a severe intellectual disability disorder caused by mutations in B56{delta}. Unlike other PP2A holoenzymes, PP2A-B56{delta} is regulated through a unique dual autoinhibition mechanism in which the N- and C-arms occlude the catalytic site while a substrate-mimicking short linear motif (SLiM) blocks the substrate-binding pocket. Although disease-associated mutations have been shown to alter enzyme activity, the molecular mechanism underlying activation of PP2A-B56{delta} and the effects of pathogenic mutations remain poorly understood. Here, we combined cryo-electron microscopy (cryo-EM), enhanced-sampling molecular dynamics (MD) simulations, Markov state model (MSM) construction, and transition-state analysis using Transition State identification via Dispersion and vAriational principle Regularized neural networks (TS-DAR) to characterize the conformational landscape of the disease variant E198K. Our cryo-EM analysis identified two distinct structures of E198K: an inactive closed-form with the N/C-arms resolved and an active loose-form in which the N/C-arms become highly flexible and could not be fully resolved. These structures therefore established that activation is governed by conformational changes of the N/C-arms but did not reveal the underlying mechanism. Starting from the inactive closed-form, we generated over 1,600 trajectories with an average length of 1,260 ns combined for E198K and wild-type (WT) PP2A-B56{delta}. TS-DAR identified four metastable states and two major activation pathways connecting inactive and active conformations. We found that activation occurs through progressive loosening of the N/C-arm interface while maintaining the overall holoenzyme architecture, rather than a complete opening of the interface. This mechanism exposes both the catalytic site and substrate-binding pocket. Comparison of E198K and WT revealed that the disease-associated mutation shifts the conformational equilibrium toward active states while leaving the transition-state ensemble largely unchanged. Mechanistically, E198K disrupts a salt-bridge network and weakens interactions between the internal loop and the C-arm that normally stabilize active-site occlusion. The resulting increase in C-arm mobility promotes active-site exposure and explains the elevated catalytic activity of the mutant. Together, these findings establish a previously uncharacterized activation mechanism for PP2A-B56{delta} and provide an atomic-level explanation for how the pathogenic E198K mutation allosterically promotes holoenzyme activation.

biophysics↗

bioRxiv2026

GAMETE maps the genetic architecture of chromatin accessibility in rice pollen at single-nucleus resolution

BackgroundDissecting the genetic basis of cell-type-specific gene regulation during gametogenesis remains a major challenge. Population-level studies mask cellular heterogeneity, while the extreme data sparsity of single-cell profiling has precluded robust genetic mapping. ResultsWe present GAMETE (Genetic Architecture Mapping of Epigenetic Traits at single-nucleus resolution), an integrated framework combining MPS-ATAC-seq, a high-throughput single-nucleus ATAC-seq method, with robust computational approaches for genotype inference and genetic mapping from sparse single-nucleus data. Applying GAMETE to hybrid rice pollen, we simultaneously profiled chromatin accessibility and inferred the genotypes of 4,887 individual haploid nuclei, revealing distinct chromatin landscapes across pollen cell types. This uncovered an unexpected elevation of chromatin accessibility at gypsy retrotransposons in microspores preceding their silencing in sperm cells, exposing a surveillance gap that may contribute to genome expansion. The synchronized profiling enabled us to construct a single-cell recombination map, map segregation distortion loci and trace their developmental origins, and identify 16,113 chromatin accessibility QTLs (caQTLs), 48.6% of which exhibited pronounced cell-type specificity. Analysis of introgression lines supported a cell-type-specific trans-acting caQTL regulating the pollen-essential gene DTM1. ConclusionsThis work establishes GAMETE as a broadly applicable framework for dissecting the genetic architecture of chromatin accessibility during gametogenesis without the need for subsequent generations.

genomics↗

bioRxiv2026

Cardiomyocytes Undergo a Mesenchymal-Like Fate Transition in Myocardial Fibrosis

BACKGROUNDMyocardial fibrosis, a pathological hallmark of adverse cardiac remodeling and heart failure, has been conventionally attributed to the activation of resident fibroblasts. Although recent studies suggest contributions from non-fibroblast lineages, direct in vivo genetic evidence that cardiomyocytes can undergo a mesenchymal-like fate transition during myocardial fibrosis remains absent. This study aims to investigate whether such a transition occurs and to elucidate the underlying regulatory mechanisms. METHODSHuman myocardial infarction (MI) tissues were analyzed by immunohistochemistry and integrated with public single-nucleus RNA sequencing (snRNA-seq) data to detect mesenchymal-like signatures in cardiomyocytes. Genetic lineage-tracing was performed in MI mice, and in cardiomyocyte-specific Hgs (hepatocyte growth factor-regulated tyrosine kinase substrate) gene knockout mice, to map the fate of cardiomyocyte-derived cells. Mechanistic insights were obtained through proteomic and snRNA-seq analysis of Hgs knockout hearts and validated through gain- and loss-of-function experiments targeting Aldh1a2 (aldehyde dehydrogenase 1 family member A2). RESULTSIn human MI samples, a subset of cardiomyocytes showed reduced expression of cardiomyocyte markers concurrent with acquisition of mesenchymal-associated markers. Genetic lineage tracing demonstrated that adult cardiomyocytes can adopt a mesenchymal-like cell fate during post-MI remodeling. We identify HGS as a factor constraining this transition. Hgs knockout in adult cardiomyocytes upregulated Aldh1a2, triggered the mesenchymal-like fate transition, and gave rise to cells expressing markers of activated fibroblasts or osteoblasts, accompanied by pronounced myocardial fibrosis and calcification. Forced Aldh1a2 overexpression in cardiomyocytes drove the mesenchymal-like fate transition in vitro and in vivo, whereas Aldh1a2 deletion in cardiomyocytes mitigated MI-induced myocardial fibrosis. CONCLUSIONSThis study provides in vivo genetic evidence that adult cardiomyocytes possess the capacity to undergo a mesenchymal-like fate transition under pathological conditions. Our data suggest that HGS and ALDH1A2 serve as regulators of the transition, offering a new basis for understanding cellular and molecular mechanisms of myocardial fibrosis. Novelty and SignificanceO_ST_ABSWhat Is Known?C_ST_ABSO_LIMyocardial fibrosis is primarily driven by resident fibroblast activation, with additional contributions from cardiac CD34+ cells, pericytes, and macrophages. C_LIO_LIAdult cardiomyocytes exhibit phenotypic plasticity and transdifferentiate into epicardial-like or pacemaker cells under specific conditions. C_LI What New Information Does This Article Contribute?O_LIA subset of cardiomyocytes adopts a mesenchymal-like cell fate during myocardial fibrosis, marked by downregulation of cardiomyocyte identity markers and loss of aligned cell-cell contacts. C_LIO_LIThese cells acquire mesenchymal morphology and markers, ECM components, migratory gene signatures, and proliferative capacity. C_LIO_LIHGS and ALDH1A2 act as regulators of this mesenchymal-like fate transition. C_LI Myocardial fibrosis drives heart failure progression, yet the cellular sources of pathological fibroblasts remain incompletely defined. Here, we demonstrate that a subset of cardiomyocytes adopts a mesenchymal-like cell fate during myocardial fibrosis by using an integrated approach combining human MI samples, murine genetic lineage tracing, and snRNA-seq. Mechanistically, we identify HGS and ALDH1A2 as regulators of this transition. Cardiomyocyte-specific Hgs deletion upregulates Aldh1a2, triggering the mesenchymal-like fate transition. Furthermore, Aldh1a2 overexpression drives this transition, while its deletion attenuates MI-induced fibrosis. These findings reveal a previously unrecognized plasticity of adult cardiomyocytes and identify potential therapeutic targets for fibrotic heart disease.

genetics↗

bioRxiv2026

Combinatorial screening of nanoparticles for nose-to-brain RNA delivery to modulate neuroinflammation after traumatic brain injury

Traumatic brain injury (TBI)-induced neuroinflammation can evolve over weeks or months, contributing to ongoing secondary damage and worsening neurological recovery. RNA-based therapeutics hold great potential to regulate inflammatory signaling, but delivery to the brain remains challenging because of the blood brain barrier. Intranasal administration offers a direct non-invasive route for brain access but is often limited by low delivery efficiency. Here we constructed a combinatorial library of DNA-barcoded 103 lipid nanoparticles by varying lipid components with diverse headgroup chemistries and bioreactive moieties. A high throughput screening of these nanoparticles in vivo following intranasal administration led to the identification of top candidates with highest brain accumulation. Intranasal delivery of an antagomir targeting microRNA-9-5p loaded nanoparticle effectively reduced cerebral microRNA-9-5p levels, suppressed inflammatory markers, and improved neurological outcomes in TBI. These results demonstrate a systematic approach for optimizing intranasal lipid nanoparticle design and support the feasibility of RNA delivery to modulate neuroinflammation after brain injury.

bioengineering↗

bioRxiv2026

Daraxonrasib (RMC-6236) is an effective targeted therapy for RAS-mutant neuroblastoma

Neuroblastoma (NB) is the most common extracranial solid tumor in children. Relapsed or refractory (R/R) high-risk (HR) NB tumors continue to exhibit poor outcomes despite intensive and protractive multimodal therapy. Activating mutations in the RAS- mitogen-activated protein kinase (MAPK) pathway are frequently observed in R/R HRNB. The early promise of ALK inhibitors to treat ALK-mutant NB underscores the ability of appropriate targeted therapies to improve outcomes for HRNB patients. While MAPK pathway activation is prominent in HRNB, FDA-approved MEK inhibitors and KRAS G12C inhibitors have failed to demonstrate significant preclinical single-agent activity. Daraxonrasib (RMC-6236), a potent and selective RAS(ON) inhibitor, has demonstrated activity in both preclinical models and early phase clinical trials of RAS-mutant adult cancers. A subset of R/R HRNB tumors is noteworthy for containing diverse RAS-mutations, providing rationale for RMC-6236 investigation. In this study, we evaluated the therapeutic efficacy and oncogenic signaling modulation of RMC-6236 across NB models harboring RAS pathway activation. RMC-6236 as a single-agent treatment led to a significant decrease in cell viability, suppression of downstream MAPK signaling, upregulation of the MAPK pathway effector protein BIM, and increased cell death in RAS-mutant NB models as well as in NF1-mutant NB models. In vivo studies evidenced that RMC-6236 had on-target activity that significantly reduced tumor growth and extended survival in RAS-mutant HRNB mouse models. Furthermore, RMC-6236-induced both BCL-2 and BIM upregulation and enhancement of BIM:BCL-2 complexes in RAS-mutant NB. As such, the BCL-2 inhibitor venetoclax further enhanced RMC-6236-mediated killing by disrupting RMC-6236 enhanced BIM:BCL-2 complexes. These findings demonstrate that RMC-6236 is a rationale targeted therapy for RAS-mutant NB, a subset of NB that is progressively understood as conferring particularly poor outcomes. RMC-6236 is a clinically relevant drug that can successfully target the MAPK pathway in these cancers. This study supports expanded clinical testing of this novel therapy to this important subset of neuroblastoma.

cancer biology↗

bioRxiv2026

A Unified and Interpretable Framework for Evaluating Fluorescence Trace Quality in Transcription Kinetics

Quantifying transcriptional dynamics from fluorescence traces is a powerful approach to understanding gene regulation, but such analysis critically depends on the quality of the fluorescence signal. Experimental researchers often lack an objective and computationally simple way to assess trace quality before kinetic modeling. In this study, we fill in this gap via systematically investigating two key factors (i.e., signal-to-noise ratio (SNR) and trace length) using synthetic data generated from a composite-state Hidden Markov Model (cpHMM) simulator. By analyzing thousands of simulated traces, we identified quantitative thresholds (SNR [≥] 30 dB and length [≥] 360) beyond which transcriptional dynamics can be reliably captured for kinetic inference. Building on these findings, we further discovered a unified and easily computable quality indicator based on the difference between the first two autocorrelation lags. A threshold value of approximately 0.07 effectively separates reliable from low quality traces, providing a simple yet robust criterion for data selection. Together, these results establish a practical framework for assessing fluorescence trace reliability, offering experimental researchers an interpretable and computationally efficient tool to ensure data quality prior to transcription kinetics modeling.

bioinformatics↗

bioRxiv2025

Ribosomal Epistatic Interactions Drive the Emergence of High-Level Streptomycin Resistance in Escherichia coli

The widespread use of antibiotics has raised serious concerns about the emergence and dissemination of antibiotic resistance in the environment. Studies reveal that environmental exposures to antibiotics and other non-antibiotic pollutants can promote the development of high-level antibiotic resistance via de novo mutations. However, specific genotypes conferring strong resistance in resistant mutants, particularly the roles of co-occurring mutations, remained poorly understood. This study fills this knowledge gap by constructing site-specific Escherichia coli mutants and demonstrating that it was the epistatic interactions that conferred the observed strong streptomycin resistance in native E. coli isolates. Three ribosomal mutations (rpsED142N, rpsLR86S and rsmGW150fs), which co-evolved under environmentally relevant selection pressures, acted synergistically to confer resistance far exceeding that of each individual mutation. The interactions between the rsmG frameshift mutation and other reported rpsL point mutations were also investigated. The findings unravel the essential but previously overlooked role played by specific co-evolving mutations in the acquisition of both high-level streptomycin resistance and fitness compensation. The findings also underscore a strong and increasing need to investigate whole genomes of antibiotic-resistant bacteria and identify potential epistatic mutations conferring resistance phenotypes. The integration of those genetic mutations as antibiotic resistance biomarkers will complement with the resistome profiling and enable more accurate antibiotic resistance monitoring and environmental risk assessment. SynopsisMultiple ribosomal mutations co-evolved under environmentally relevant exposure conferred high-level streptomycin resistance via epistatic interactions. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=132 SRC="FIGDIR/small/694165v1_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@e47b2borg.highwire.dtl.DTLVardef@525e27org.highwire.dtl.DTLVardef@1a36e4dorg.highwire.dtl.DTLVardef@9eaf34_HPS_FORMAT_FIGEXP M_FIG Table of Contents Graphic C_FIG

microbiology↗

bioRxiv2025

Amaranth: Enhanced Single-Cell Transcript Assembly via Discriminative Modeling of UMI Reads and Internal Reads

MotivationSingle-cell RNA sequencing has transformed transcriptome profiling at cellular resolution, yet accurate reconstruction of full-length transcripts for individual cells remains a central challenge. Emerging scRNA-seq protocols can produce reads that span entire transcripts, enabling isoform-level expression analysis. For example, Smart-seq protocols combine UMI-linked reads that index and stitch together multiple reads from the same molecule, with internal reads filling coverage gaps. We demonstrate that these read types exhibit markedly different biological and statistical properties in strandness, 5/3 coverage bias, and genomic locality. Existing assemblers fail to leverage these distinctions, yielding suboptimal assembly. ResultsWe developed Amaranth, a novel single-cell assembler that discriminatively models UMI and internal reads. Amaranth implements heuristics specifically designed to address the distinct biases of UMI-linked and internal reads, enabling accurate strandness assignment for internal reads, reliable splicing graph refinement, and precise transcript start site determination. We also developed Amaranth-meta, which integrates information across cells to enhance individual cell assemblies. Benchmarked on Smart-seq3 datasets from human HEK293T and mouse fibroblast cells, Amaranth outperformed other state-of-the-art assemblers in assembling individual cells and in meta-assembly. Amaranth advances isoform-level analysis in single-cell transcriptomics, facilitating detailed studies at cellular resolution. Availability and ImplementationAmaranth is implemented in C++ and is freely available at https://github.com/Shao-Group/amaranth under the BSD-3-Clause license. Scripts, documentation, and data for reproducing experiments in this manuscript are available at https://github.com/Shao-Group/amaranth-test.

bioinformatics↗

bioRxiv2025

OASIS: in vivo AAV-mediated transduction and genome editing of adult oligodendrocytes

New viral approaches have revolutionized neuroscience by precisely delivering genes in neurons; for example, to control or monitor activity in specific neuronal cell types. In contrast, the manipulation of oligodendrocytes requires the Cre-LoxP system and gene-by-gene engineering, breeding, and genotyping. Here we introduce OASIS (Oligodendrocyte AAV-CRISPR mediated Specific In vivo editing System), a versatile platform that combines SELECTIV, an AAV-receptor-based transduction strategy, with HiUGE, an NHEJ-mediated CRISPR/Cas9 knock-in approach. We show efficient and specific oligodendrocyte transduction across the brain and tagging of endogenous cytoskeletal, myelin, cell adhesion, scaffolding, and junctional proteins. OASIS enables sparse yet reliable labeling, allowing direct visualization of a proteins subcellular localization with single-cell resolution. We successfully fused the biotin-ligase TurboID with endogenous oligodendroglial Neurofascin-155, thereby achieving targeted biotinylation of the axoglial junction. OASIS is rapidly customizable for any gene-of-interest. Together, OASIS overcomes longstanding barriers in oligodendrocyte biology, providing a powerful system for precise, customizable genome editing and subcellular visualization in the adult brain.

neuroscience↗

bioRxiv2025

ACE2 Phosphorylation Modulates Angiogenesis via the Activator Protein-1

BackgroundAngiogenesis plays a crucial role in organ development. However, aberrant blood vessel growth is involved in various diseases, including tumors and neovascular eye diseases. Angiotensin-converting enzyme 2 (ACE2) is a critical enzyme regulating the health of cardiovascular system, and its post-translational modifications (PTMs) are crucial to determine ACE2 expression level and activity. Here, we studied how the PTM of ACE2 in vascular endothelial cells (ECs) affect pathological retinal neovascularization and tumor angiogenesis. MethodsThe angiogenic capabilities of ECs were assessed by tube formation, sprouting assays, and 5-ethynyl-2-deoxyuridine (EdU) and filopodia staining. EC angiogenesis was examined by poteome profiler array and aortic ring assays in vitro and by the oxygen-induced retinopathy (OIR) and tumor angiogenesis models in vivo. High-throughput screening involving data from RNA-seq, ATAC-seq, and ChIP-seq were used to explore the epigenetic and transcriptional regulations of pro-angiogenic genes regualtged by ACE2 PTMs. ResultsACE2 Ser-680 dephosphorylation in connection with Lys-788 ubiquitination increased EC angiogenic phenotype, which were manifested by aberrant vascularization in mouse OIR and tumor models. ACE2 Ser-680 dephosphorylation led to the activation of activator protein-1 (AP-1), which transactivated multiple genes involved in angiogenesis. AP- 1 inhibition mitigated such angiogenesis in vivo. ConclusionOur findings show a novel PTM mechanism of ACE2 involved in pathological angiogeneis. Specifically, ACE2 Ser-680 dephosphorylation facilitated AP-1 transactivation of the downstream pro-angiogenic genes in ECs.

cell biology↗