Biology subjects

Zhang, H.

Publications and source records attributed to Zhang, H..

At least 289 records · Page 16Linked to original sources

bioRxiv2025

PlantScience.ai: An LLM-Powered Virtual Scientist for Plant Science

The accelerating growth of plant science literature presents a major challenge for researchers seeking to extract accurate, up-to-date knowledge from an increasingly fragmented and domain-specific corpus. General-purpose large language models (LLMs), while powerful, often misinterpret plant science terminology and lack mechanisms for source traceability. We created PlantScience.ai, a virtual plant biology scientist powered by our automated scientific knowledge graph construction pipeline (AutoSKG). PlantScience.ai exhibits expert-level reasoning in plant biology and maintains scholarly rigour in its citations. Through continuous learning, it integrates the latest research, ensuring that its knowledge base remains current and scientifically robust. Apart from providing the answers to the scientific questions, PlantScience.ai can interact with human scientists, follow instructions, and retrieve information with citation awareness, grounding each response in primary sources to ensure accuracy and verifiability. PlantScience.ai marks a pivotal advance toward a collaborative scientific paradigm in which virtual and human plant scientists work synergistically to accelerate discovery while preserving the unique value of human insight. PlantScience.ai is available at https://plantscience.ai.

plant biology↗

bioRxiv2025

In host mutational adaptation of Mycobacterium tuberculosis complex strains

BackgroundTuberculosis (TB) is the second leading cause of death from an infectious disease worldwide. Mycobacterium tuberculosis complex (MTBC), the causative bacteria of TB, is becoming increasingly resistant to anti-TB drugs, resulting in poorer treatment outcomes. The mutations arising in MTBC strains during infection provide a record of bacterial diversification and adaptation, and indirect evidence on the selective pressures and conditions that MTBC encountered in vivo, such as those exerted by the immune system and antibiotic therapies. MethodsWe conducted a meta-analysis of MTBC sequenced strains with multiple clinical isolates sequenced from the same patient, from published studies and TB Portals. We applied stringent genomic QC criteria to keep only clonal isolates and applied robust genomic pipelines to identify mutations arising de novo during infection. A convergent evolution approach was applied to identify heavily mutated genes, operons, and candidate promoter across strains of multiple patients. We estimated the frequency of drug resistance acquisition during treatment for the subset of patients with available drug treatment data. ResultUsing 5,899 high-quality genomes from 1,056 TB patients after ensuring clonality of isolate genomes we identified limited within-host diversity was identified including 3,296 fixed mutations across 501 patients. A total of 21 genes, 25 operons and 27 promoter regions were statistically enriched by mutations compared to the rest of the genome, and additional loci with established or plausible adaptive roles approaching statistical significance. Significantly, this included multiple loci known to be involved in resistance to first-, second-, and last-line anti-TB drugs. Fluoroquinolone resistance was acquired more frequently during treatment than resistance to any other anti-TB drug. Previously reported candidate drug-resistance and -tolerance genes (prpR, Rv2571c, fadD11, helY, ndhA, Rv0139, fadE5, and mce1 operon) were also identified. Genes encoding regulators (phoR, whiB6 and mycP1) and effectors (espK and eccE1) of the virulence ESX-1 locus were frequently mutated in host. ConclusionsHere we analysed a large dataset of MTBC within-host genetic diversity. We show that frequently mutated genes in MTBC during infection reveal known and biologically plausible in host adaptations, predominantly associated drug resistance, but also in genes involved in pathogenesis. The higher resistance acquisition rate observed for fluoroquinolones may have important clinical relevance. We reveal a list of candidate loci which will require mechanistic characterisation and whose impact on disease progression will need to be investigated.

genomics↗

bioRxiv2025

MDFIC2 is a sensory neuron-specific PIEZO channel auxiliary subunit

PIEZO channels are critical for sensory mechanotransduction. While MyoD-family inhibitor proteins were identified as PIEZO1 auxiliary subunits, their broader regulatory roles, particularly in sensory cells, remained unclear. Here we demonstrate native MDFIC and MDFI regulate endogenous PIEZO channel currents in various non-sensory cell types. However, neither MDFIC nor MDFI are expressed in primary sensory neurons. In these cell types we identified an uncharacterised member of this family, Mdfic2/Gm765, that shares the ability to physically bind to PIEZO1 and PIEZO2. MDFIC2 is selectively expressed in subsets of mechanosensitive neurons, including dorsal root ganglia, trigeminal ganglia, and vagal sensory neurons. Like its paralogues, MDFIC2 alters PIEZO1/2 mechanosensitivity and inactivation kinetics, converting them into high-threshold slowly inactivating mechanoreceptors. Extensive cryo-EM reveals a conserved binding pocket for these auxiliary subunits in the pore modules of both PIEZO1 and PIEZO2 mediated by the post-translationally modified distal C-termini of MyoD-family inhibitor proteins. This provides a comprehensive structural and functional characterisation of MyoD-family inhibitor proteins as PIEZO1/2 channel regulators and offers new insights into sensory physiology and mechanical pain mechanisms.

biophysics↗

bioRxiv2025

Structure and function of the nairovirus cap-snatching endonuclease

Nairoviruses include several human pathogens such as Crimean-Congo hemorrhagic fever virus (CCHFV) and Kasokero virus (KASV). The cap-snatching endonuclease (EN) domain of the viral polymerase is essential for transcription and represents a promising antiviral target. However, the structural and functional mechanisms of nairovirus ENs remain poorly understood. Here, we describe biochemical and structural studies of the ENs from CCHFV and KASV. Biochemical assays demonstrate that the RNA endonuclease activity of both ENs is activated by manganese ions and exhibits a preference for uridine-rich RNA substrates. This activity is inhibited by three metal-chelating inhibitors (DPBA, L-742,001, and BXA), with BXA displaying the highest binding affinity and inhibitory potency. We further determine nine crystal structures of CCHFV and KASV ENs in apo, metal ion-bound, and inhibitor-bound states. Comparative structural analysis uncovers a two-metal-ion binding mode unique to nairovirus ENs, in which conserved residues coordinate two manganese ions via bridging water molecules. In the inhibitor-bound structures of KASV EN, BXA forms additional stabilizing interactions with the enzyme, explaining its superior inhibitory effect. Functional assays further confirm that the two-metal-ion mechanism is critical for viral transcription. These findings provide a structural foundation for the rational design of antivirals against CCHFV and related pathogens.

microbiology↗

bioRxiv2025

Histology-informed spatial domain identification through multi-view graph convolutional networks

Identifying spatial domains is crucial in spatial transcriptomics, yet effectively integrating gene expression, spatial location, and histology remains challenging. We present STESH, a Spatial Transcriptomics clustering method that combines Expression, Spatial information and Histology. STESH extracts histological features using a convolutional neural network and generates expression, histology, spatial, and collaborative convolution modules for a multi-view graph convolutional network with a decoder and attention mechanism. We evaluated STESH on multiple tissue types and technology platforms. STESH consistently outperformed ten state-of-the-art methods, achieving superior clustering accuracy with the highest scores in adjusted Rand index, normalized mutual information, and Fowlkes-Mallows index.

bioinformatics↗

bioRxiv2025

Distinct and compensatory roles of Stag1 and Stag2 in post-mitotic genome refolding

The three-dimensional architecture of the eukaryotic genome is largely shaped by the cohesin complex, which contains either Stag1 or Stag2 subunits. Although both subunits contribute to chromatin organization, their specific functions in de novo loop formation during post-mitotic genome refolding remain elusive. Here, we leverage the mitosis-to-G1 transition to dissect their individual roles. We found that Stag1 depletion has a negligible impact on post-mitotic genome restructuring or transcription reactivation. In contrast, Stag2 orchestrates chromatin remodeling in a manner that is both cell cycle stage-specific and chromatin context-dependent. During early-G1, Stag2 preferentially associates with euchromatin, where it drives the rapid formation of small chromatin loops. This facilitates prompt promoter-enhancer (P-E) contact formation and enables efficient transcription activation. As the nuclear concentration of Stag2 increases by late-G1, it progressively suppresses large loops, likely due to its shorter chromatin residence time and its potential to competitively displace the more extrusion-capable Stag1-associated cohesin. Mechanistically, Stag2-mediated loop extrusion is constrained by CTCF-bound barriers, rather than by genomic travel distance. Although Stag2 associates rapidly with euchromatin in early-G1, its recruitment to heterochromatin is delayed until late-G1. Simultaneous depletion of both Stag proteins results in a synergistic loss of virtually all structural loops and a more severe disruption of transcription than that caused by individual deletions. Together, these results establish Stag2 as the principal regulator of post-mitotic genome reorganization among Stag paralogs, mediating spatiotemporal control of chromatin architecture, while Stag1 provides compensatory support to ensure functional robustness.

molecular biology↗

bioRxiv2025

Brassinosteroids promote sugar synthesis by inhibiting BIN2 phosphorylation of phosphoenolpyruvate carboxykinase

Sugar is both an essential energy source and the major substrate for cell wall biosynthesis during plant growth, yet how growth-promoting hormones regulate sugar synthesis remains unclear. Here, we show that the brassinosteroids (BRs) promote gluconeogenic and photosynthetic sugar synthesis by activating phosphoenolpyruvate carboxykinase (PCK), which catalyzes the conversion of oxaloacetate to phosphoenolpyruvate, a central step in primary metabolism. Arabidopsis BR-deficient mutants display reduced PCK1 activity and elevated phosphorylation at conserved Ser-62 and Thr-66 residues. BR treatment induces PCK1 dephosphorylation and activation, whereas the GSK3-like kinase BIN2 phosphorylates these sites, altering quaternary structure and inhibiting PCK1. Phospho-blocking mutations of Ser-62/Thr-66 confer BR-independent PCK1 activity and enhance seedling growth, while phosphomimetic mutations reduce PCK1 activity and impair seedling growth and establishment. BR also promotes PCK dephosphorylation and activation in photosynthetic leaves of maize and sorghum. Our study demonstrates that BR regulates primary metabolism via GSK3/BIN2-mediated phosphorylation of PCK, thereby promoting gluconeogenesis and photosynthesis.

plant biology↗

bioRxiv2025

Global changes in alternative splicing are associated with insecticide response and resistance

Alternative splicing (AS) promotes phenotypic plasticity to adverse conditions by altering transcripts involved in stress adaptation. However, whether changes in AS occur transcriptome-wide or in only a few key genes is unclear. Agricultural insect pests are regularly exposed to xenobiotic stress from insecticide applications and thus develop resistance. We show that the pest Drosophila suzukii, resistant to multiple insecticides, exhibits increased global AS events compared to susceptible flies. Alternatively spliced genes are enriched in multiple processes including stress response and insecticide resistance, suggesting AS is a mechanism underlying insecticide resistance development. Furthermore, sublethal insecticide exposure promotes AS events even in the absence of substantial differential gene expression. This study provides insights into the role of AS in enabling insects to diversify genome function to survive acute insecticide treatment and to develop xenobiotic resistance.

genomics↗

bioRxiv2025

Insights from pooled CRISPRi single-cell screens in K562 cells reveal gene functions, regulatory networks, and highlight opportunities and limitations

Pooled CRISPR screening combined with single-cell RNA sequencing (scRNA-seq) has emerged as a powerful strategy for dissecting gene function and reconstructing gene regulatory networks (GRNs) in complex biological systems. This approach enables high-throughput, parallel perturbation of multiple genes while providing transcriptome-wide readouts at single-cell resolution, overcoming many limitations of traditional arrayed screens. However, its broader application remains limited by technical challenges, including variable perturbation efficiency and difficulties in accurately identifying perturbed cells. In this study, we adapted and applied a modified CRISPR droplet sequencing (CROP-seq) protocol using CRISPR interference (CRISPRi) in K562 cells to knockdown six transcription factors (TFs): LMO2, TCF3, LDB1, MYB, GATA2, and RUNX1. Our modified approach, which allows direct capture of sgRNAs from the cDNA library without a separate enrichment step, significantly improved sgRNA assignment per cell. We successfully achieved reproducible knockdown of three TFs (MYB, GATA2, and LMO2), captured the impact of these perturbations on the TF target genes, and enabled us to reconstruct their GRNs and identify key regulons and transcriptional targets. These networks revealed both previously established (such as LMO2 GATA2 interaction) and novel regulatory interactions, which we independently validated, providing new insights into hematopoietic transcriptional control. To assess the efficiency of CRISPRi based pooled perturbation, we additionally analyzed publicly available pertrub-seq CRISPRi datasets and found that only [~]40-50% of targeted genes led to effective knockdown, underscoring the variability in perturbation efficiency across experiments. Together, our results demonstrate both the potential and the current technical limitations of pooled CRISPRi-based single-cell screens. While this integrated approach holds great promise for high-resolution functional genomics, further optimization and standardized benchmarking are essential to improve its reliability, scalability, and reproducibility.

genomics↗

bioRxiv2025

Adjacent Rare-Earth Separation via a Protein Atomic Ruler

The separation of rare-earth elements (REEs) poses a formidable challenge due to their nearly identical ionic radii and chemical properties. Here, we present a transformative strategy for REE separation using a multimetal ion-stacking metalloprotein framework (MIF) that functions as an atomic ruler, effectively amplifying subtle differences in REE ionic radii. This approach achieves exceptional selectivity, enabling the separation of all 13 adjacent REE pairs with ultrahigh purity (up to 99.999%). Remarkably, the MIF retains its lanthanide-binding capacity over 410 consecutive absorption-desorption cycles, demonstrating outstanding stability. Structural insights reveal that the MIFs densely packed REE coordination environment magnifies minute radius variations--a key mechanism underlying its unparalleled separation efficiency. Our MIF-based strategy offers a sustainable, scalable solution to rare-earth separation in industrial applications.

biophysics↗

bioRxiv2025

Benchmarking Perturbation Tools for the Noncoding Genome

Deciphering the functionality of the noncoding genome which includes important cis-regulatory elements (CREs) and transcribed noncoding RNA genes remains technically challenging. Here, using massively parallel genetic screening, we systematically benchmark the performance of five representative loss-of-function perturbation tools, including single guide RNA (gRNA) mediated SpCas9 cleavage or CRISPR interference, and paired gRNA (pgRNA) involved dual-SpCas9, Big Papi (paired SpCas9 and SaCas9) or dual-enAsCas12a fragment deletion methods, in decoding the roles of the noncoding genome. For targeting CREs such as enhancer, dual-SpCas9 outperforms other methods with superior efficiency of destroying functional genomic regions. For perturbing noncoding RNA genes, in addition to dual-SpCas9, other RNA-targeting methods such as RNA interference are recommended to discriminate transcript-dependent or -independent roles. A deep learning model DeepDC with associated web server is built to facilitate optimal dual-SpCas9 pgRNA design for efficiently deleting a genomic fragment. Together, our work provides practical guidance on selecting appropriate loss-of-function tools to resolve the functional complexity of the noncoding genome.

genetics↗

bioRxiv2025

Stromal subsets modulate T-cell infiltration in early breast cancer

Recent studies of the tumour microenvironment have elucidated the heterogeneity of stromal cells, with increasing evidence suggesting that stromal subsets play an important role in regulating anti-tumour immunity in breast cancer. However, the functional diversity of these cells within the tumour immune microenvironment and how they interact with immune cells in a spatial and clinical context remain poorly understood. We performed multiplex immunofluorescence on tumour microarrays from two cohorts consisting of 591 breast cancer patients to assess the abundance and spatial co-localisation of stromal and immune subsets and their correlation with clinicopathological features and patient outcomes. We found that stromal cells were spatially distinct. A perivascular-like subset that was disseminated throughout the stroma rather than restricted to vessel-adjacent regions was enriched in an immune cold environment and associated with T-cell exclusion. An inflammatory-like cancer-associated fibroblast subset was associated with segregation of T cells from cancer cells. Our findings highlight the differential impact of stromal subsets on immune infiltration and activation within the breast cancer tumour microenvironment with potential implications for patient outcomes. SignificanceThis study characterised spatially-defined interactions between stromal and immune subsets in large clinical cohorts of early breast cancer. Findings from this study will contribute to gaps in current knowledge in how diverse stromal cell subsets, particularly novel subsets, interact with immune cells in a clinically-relevant context.

cancer biology↗

bioRxiv2025

Temperature-Dependent Ion Migration Underlies Sequence-Specific RNA Collapse

Ions and temperature jointly regulate RNA structure, dynamics and phase behavior, yet their coupled effects remain poorly understood at the molecular level. Single-stranded RNA (ssRNA), a ubiquitous and functionally versatile class of RNA, presents a particularly challenging target due to its intrinsic flexibility and pronounced sensitivity to ionic and thermal perturbations. Here, we extend our previously validated coarse-grained RNA model by introducing temperature-dependent divalent ion-phosphate potentials along with revised stacking interactions to elucidate how electrostatics, stacking, and hydration collectively determine ssRNA behavior. Our simulations quantitatively reproduce experimental SAXS profiles across a broad range of ionic conditions and reveal a non-monotonic temperature dependence of RNA compaction: ssRNAs expand upon heating, reach a sequence-specific maximum size, and then collapse as enhanced counterion condensation dominates. Rising temperature strengthens ion-RNA interactions, leading to a reorganization from diffusive to inner-sphere coordination, directly linking RNA collapse to ion dehydration. Our results establish that the ion atmosphere is a dynamic, sequence-encoded extension of RNA structure. This framework provides molecular insight into how temperature and ions govern RNA conformational transitions, offering a microscopic basis for RNA thermoadaptation, cold-induced misfolding, and RNA phase transitions. Statement of SignificanceIons and temperature strongly influence RNA structure and dynamics, yet the molecular mechanisms by which these factors jointly regulate RNA behavior remain poorly understood. Using coarse-grained simulations with temperature-dependent Mg2+-phosphate interactions, we report how ion binding reorganizes around single-stranded RNAs as temperature increases. We found that unstructured RNAs undergo a non-monotonic structural transition: thermal disruption of base stacking first expands the chain, followed by the collapse driven by enhanced Mg2+ binding. This collapse arises from a temperature-induced migration of Mg2+ from diffusive ion atmosphere to direct inner-sphere binding, linking RNA compaction to ion dehydration and entropy-driven binding. These results reveal that the RNA ion atmosphere is a dynamic, structure-coupled component of RNA organization and provide a mechanistic basis for thermoresponsive RNA condensation. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=111 SRC="FIGDIR/small/683600v3_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@fe79beorg.highwire.dtl.DTLVardef@eaac88org.highwire.dtl.DTLVardef@e52bc1org.highwire.dtl.DTLVardef@19bbea0_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗

bioRxiv2025

Human Organoids Reveal PTEN-driven Mesendoderm Specification via Retinoic Acid Signaling Suppression

During early embryogenesis, epiblast cells ingress through the primitive streak (PS) and commit to a mesendoderm (MES) fate, giving rise to both mesodermal and endodermal lineages. Despite advancements in human organoid technology for modeling pre-implantation blastocyst stage, robust systems that accurately recapitulate MES specification and PS formation during the post-implantation stage remain limited. Here, we show that human induced pluripotent stem cells can be used to generate three-dimensional MES organoids that faithfully mimic in vivo human MES specification, particularly from the anterior PS. We demonstrate that MES organoid formation is dependent on PTEN expression and that loss of PTEN severely impairs the formation of mesoderm and definitive endoderm derivatives arising from MES organoids. To elucidate the molecular mechanisms underlying these defects, we conducted an integrative multi-omics analysis, including transcriptome, chromatin accessibility profiling, metabolism, and phosphoproteomics, on wild-type and PTEN-/-MES cells. These analyses revealed that PTEN suppresses retinoic acid (RA) signaling during MES lineage commitment. Furthermore, we identified the RA-degrading enzyme CYP26A1 as a downstream effector of PTEN. Notably, while excessive RA induced by PTEN ablation is detrimental to MES cell generation, physiological levels of RA are necessary. Collectively, our human MES organoids offer a valuable model for dissecting early human development, and our findings identify PTEN as a key regulator of MES fate commitment through inhibition of RA signaling.

developmental biology↗

bioRxiv2025

Leaf-age specific flood resilience in Arabidopsis thaliana is determined by distinct processes contributing to post-submergence recovery

While the molecular mechanisms mediating submergence tolerance have been extensively studied, those underpinning age-dependent resilience remain poorly characterized. In Arabidopsis thaliana, submergence elicits a leaf-age dependent phenotype in which senescence and death progress across an age gradient starting with older leaves. Here we sought to investigate the mechanisms mediating this observed differential flood resilience by interrogating leaf age-specific transcriptome and proteome changes during submergence and recovery. Following submergence, most age-dependent differences were in the magnitude or speed of transcript abundance changes, whereas qualitative leaf-age dependent responses were most apparent during recovery. This included a strong desiccation response in old leaves despite a stronger ABA-signaling response. Physiological measurements suggested that faster dehydration was facilitated by a combination of submergence-mediated reduction of ABA sensitivity and higher conductance in old leaves. We also observed a stronger induction in young shoot tissue of genes associated with endoplasmic reticulum (ER) stress and the unfolded protein response (UPR). Mutants disabled in the two UPR signaling branches were affected in new leaf formation and the ability to restore the proteome, but not in senescence, suggesting that young tissues activate ER stress recovery to permit continuation of growth. Of the mitochondrial membrane proteins differentially regulated in young leaves, loss of mitochondrial voltage-dependent anion channel function impacted submergence-recovery tolerance. Our data reveal multiple mechanisms underlying leaf age-dependent differential submergence recovery and demonstrate how tolerance is determined by an interplay between age related developmental traits and stress signaling pathways.

plant biology↗

bioRxiv2025

Structural and dynamic studies uncover a distinct allosteric modulatory site at the mu-opioid receptor

Positive allosteric modulators (PAMs) of the opioid receptor (MOR) offer a promising path toward safer opioid therapeutics, yet their mechanisms of action remain poorly understood. Here, we uncover the structural and mechanistic basis of BMS-986187, a chemically distinct MOR PAM with in vivo efficacy, using an integrated approach combining cryogenic electron microscopy (cryo-EM), molecular dynamics (MD) simulations, signaling assays, and site-directed mutagenesis. We identify a previously uncharacterized allosteric site for BMS-986187, a lipid-facing pocket formed by MOR transmembrane helices 2, 3, and 4, distinct from sites occupied by other known MOR PAMs or negative allosteric modulators. BMS-986187 engages both receptor residues and a neighboring cholesterol molecule, suggesting a cooperative ligand-lipid mechanism. Our studies pinpoint residues essential for allosteric modulation, while information-theory analysis of MD trajectories uncovers specific allosteric communication pathways linking the PAM site to both the orthosteric agonist DAMGO and the G protein interface. Together, these findings redefine the landscape of MOR allosteric modulation by revealing a novel binding site, a potentially lipid-sensitive allosteric mechanism, and the molecular wiring of long-range communication within MOR. This work provides a new molecular framework for the rational design of PAMs targeting opioid receptors with improved precision and possible therapeutic potential.

pharmacology and toxicology↗

bioRxiv2025

ARHGEF17 Deficiency Induces Endothelial Dysfunction and Intracranial Aneurysm Formation via RhoA/ROCK2/MLC Signaling Pathway

BACKGROUNDGenetic susceptibility is a major determinant in intracranial aneurysm (IA) formation and rupture, yet the underlying mechanisms linking genetic variation to vascular dysfunction remain largely unknown. We have identified mutations in ARHGEF17, a guanine nucleotide exchange factor that regulates RhoA activation and cytoskeletal organization, as potential risk variants for IA. Given ARHGEF17s regulatory role in endothelial barrier integrity and actin remodeling, we hypothesized that ARHGEF17 deficiency promotes IA pathogenesis through dysregulation of the RhoA/ROCK2/MLC signaling axis, leading to endothelial dysfunction and vascular wall instability. METHODSCRISPR-Cas9-mediated ARHGEF17 knockout (ARHGEF17-/-) mice and morpholino-based ARHGEF17-deficient zebrafish were established to assess the in vivo vascular effects of ARHGEF17 loss. An intracranial aneurysm model combining elastase injection and deoxycorticosterone acetate (DOCA)-induced hypertension was used to evaluate aneurysm incidence, rupture rate, and survival. Structural remodeling of the Circle of Willis (CoW) was assessed by Victoria Blue, EVG, and Picrosirius Red staining, as well as immunofluorescence for -SMA, OPN, CD31, and inflammatory markers. Complementary in vitro studies were performed in HUVECs using lentiviral ARHGEF17 silencing (three shRNAs of varying efficiency) to examine endothelial proliferation, migration, tube formation, and barrier function (TEER). Activation of RhoA/ROCK2/MLC signaling was quantified by G-LISA and Western blotting. The ROCK inhibitor Y-27632 (10 M) was applied to determine pathway dependence. RESULTSARHGEF17-/- mice exhibited a significantly higher incidence and rupture rate of intracranial aneurysms, accompanied by fragmentation of elastic fibers, loss of collagen organization, vascular smooth muscle cell dedifferentiation, and robust inflammatory activation in the CoW. Zebrafish lacking ARHGEF17 showed frequent intracranial hemorrhage and compromised vascular wall integrity, further confirming ARHGEF17s role in cerebrovascular stability. In ECs, ARHGEF17 knockdown impaired proliferation, migration, tube formation, and barrier integrity in a silencing-efficiency-dependent manner. Mechanistically, ARHGEF17 deficiency activated the RhoA/ROCK2/MLC pathway, leading to increased phosphorylation of MLC and MYPT1 and disorganization of F-actin and junctional proteins. Pharmacological inhibition with Y-27632 restored endothelial function, normalized cytoskeletal structure, and re-established junctional continuity, indicating a ROCK2-dependent mechanism. CONCLUSIONSOur findings establish ARHGEF17 as a critical regulator of cerebrovascular integrity and identify RhoA/ROCK2/MLC mediated cytoskeletal remodeling as the mechanistic link between ARHGEF17 deficiency and aneurysm pathogenesis. Loss of ARHGEF17 compromises endothelial barrier function, triggers vascular inflammation, and promotes aneurysm formation and rupture. Importantly, ROCK inhibition rescues endothelial dysfunction, highlighting the RhoA/ROCK2/MLC axis as a promising therapeutic target for ARHGEF17 mutation-associated intracranial aneurysms.

neuroscience↗

bioRxiv2025

Evaluation of computational tools for predicting CRISPR gRNA on-target efficiency in plants.

CRISPR technologies has become an integral part of plant biotechnology, synthetic biology and basic plant research, routinely used by researchers for targeted genome modifications. CRISPR guide RNAs (gRNAs) undermines the highly programmable nature of CRISPR, enabling site-specific genome editing. However, different gRNA targets showed highly variable on-target effectiveness and poor gRNA design could amount to wasting valuable scientific resources. There has been broad development of computational and web-based tools for gRNA efficiency predictions but their performances in plant genome editing remains controversial or untested. Hence, in this study, we systematically evaluated over 20 accessible, web-based in silico gRNA on-target efficiency prediction tools using an experimental plant genome editing dataset. Excitingly, we identified multiple tools, mostly developed using machine learning, that were highly predictive of gRNA on-target genome editing efficiency in planta. The prediction scores assigned to gRNAs in the dataset by these tools were significantly correlated with the frequency of CRISPR-mediated InDels in plants. Furthermore, we evaluated efficiency prediction scores available on popular platforms such as CRISPOR and CRISPR-P which contain large numbers of non-model plant genomes. Our analysis showed that some prediction scores on CRISPOR performed quite well which allows efficient integration of on-target and off-target predictions. Overall, we believe that our study provided insights on improving gRNA design during conventional plant genome editing workflows and should also help unfamiliar researchers interested in CRISPR/SpCas9 genome editing.

plant biology↗