Biology subjects

Gu, S.

Publications and source records attributed to Gu, S..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

Targeting Putrescine Homeostasis with Lactiplantibacillus plantarum PS128 to Mitigate Autism-like Behaviors in Fmr1 KO Mice

BackgroundAutism spectrum disorder (ASD) is biologically heterogeneous and has limited mechanism-informed interventions targeting core behavioral symptoms. Emerging evidence suggests that gut microbial metabolism shapes neurobehavioral outcomes, yet the specific metabolic pathways linking gut ecology to brain function remain incompletely understood. One candidate pathway is polyamine metabolism, which links microbial amino acid metabolism to host regulation and represents a plausible but underexplored contributor to ASD-related phenotypes. Notably, the psychobiotic Lactiplantibacillus plantarum PS128 has been reported to improve social behaviors in individuals with ASD, although the molecular basis for these effects is unclear. In this study, we used Fragile X mental retardation 1 knockout (Fmr1 KO) mice, a well-established ASD model, to investigate microbiota-dependent metabolic mechanisms underlying autism-like behaviors. ResultsWe found that autism-like behaviors in Fmr1 KO mice were associated with gut dysbiosis, impaired intestinal barrier integrity, disruption of the arginine-ornithine-polyamine pathway, and elevated putrescine in the prefrontal cortex (PFC). Supplementation with PS128 remodeled the gut microbiota, reduced inflammation- and disease-associated taxa, improved intestinal structure and permeability, and restored polyamine homeostasis. Targeted metabolomics revealed an increased PFC-to-serum putrescine ratio in KO mice, which was normalized following PS128 intervention. This correction was accompanied by reduced expression of polyamine transporters in the PFC, including ATP13A family members. Causal experiments supported a functional role for putrescine, as peripheral elevation of putrescine induced autism-like behaviors in wild-type mice, whereas pharmacological inhibition of putrescine synthesis ameliorated behavioral deficits in Fmr1 KO mice. ConclusionsThese findings identify putrescine metabolic dysregulation as a key contributor to autism-like phenotypes and support the existence of an ASD subtype defined by disruption of the arginine-ornithine-polyamine axis. Integrated multi-omics and causal perturbation analyses support a model in which microbiota-targeted intervention rebalances systemic polyamine regulation along the gut-brain axis, thereby improving ASD-relevant behaviors. Our work provides mechanistic evidence linking microbial metabolism to neurochemical homeostasis and highlights the translational potential of metabolic stratification in ASD. Graphical AbstractWe identify dysregulated microbiota-driven polyamine homeostasis as a causal contributor to autism-like behaviors in Fmr1 knockout mice. A psychobiotic intervention restores gut-brain metabolic balance and rescues social and repetitive behavioral deficits through coordinated microbial and host transport regulation. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/694366v2_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@e1e780org.highwire.dtl.DTLVardef@125a3baorg.highwire.dtl.DTLVardef@201228org.highwire.dtl.DTLVardef@1880650_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2025

A Globally Representative Immunopeptidomics Approach to Identify Population-Wide Vaccine Candidates

Vaccine development has historically relied on preclinical testing using one or two cell lines, typically of Caucasian descent, contributing to vaccines that may fail to provide adequate protection across genetically diverse populations. A major factor in these failures is the lack of consideration for human leukocyte antigen (HLA) diversity, with over 30,000 HLA alleles worldwide exhibiting distinct frequencies across ethnic groups and geographic regions. Here, we present a globally representative immunopeptidomics approach that addresses HLA diversity at the earliest stages of vaccine antigen discovery. We established a panel of 30 cell lines from the 1000 Genomes Project that represent 75% of the worlds most common HLA alleles. Using a combined computational and experimental approach, we identified 18 common binding motifs (7 MHC class I and 11 MHC class II) shared across 24 cell lines from the panel. We developed an accessible bioinformatic tool that predicts globally presentable antigenic regions from any pathogen proteome by identifying peptides matching these common binding motifs. Validation with Salmonella enterica serovar Typhimurium and SARS-CoV-2 Spike protein demonstrated that our method successfully identifies known immunogenic regions, with experimentally detected epitopes showing substantial overlap with predicted regions of interest. Notably, only three cell lines were required to validate highly immunogenic S. enterica targets, including OmpC--a porin with known 100% protective efficacy--detected across all tested lines. Our approach enables researchers to rapidly screen pathogen proteomes using freely available bioinformatic tools, with optional experimental validation requiring minimal resources. By identifying antigens with broad population coverage before clinical trials begin, this method has the potential to increase vaccine success rates while ensuring equitable protection across diverse populations. The cell line panel, common binding motifs, and bioinformatic workflow are publicly available, providing an accessible pathway for developing vaccines that truly serve global populations.

immunology↗

bioRxiv2025

Predictive vision-language integration in the human visual cortex

Integrating linguistic and visual information is a core function of human cognition, yet how information from these two modalities interacts in the brain remains largely unknown. Competing frameworks, including the hub-and-spoke model and Bayesian theories such as predictive coding, offer conflicting accounts of how the brain achieves multimodal integration. To address this question, we collected a large-scale fMRI dataset and leveraged state-of-the-art AI systems to construct encoding models that probe how the human brain matches and integrates linguistic and visual information. We found that prior information from one modality can modulate neural responses in another, even in the early visual cortex (EVC). Integration neural response in EVC is governed by prediction errors consistent with predictive coding theory. Enhanced and suppressed neural responses to semantically matched cross-modal stimuli were found in distinct EVC populations, with suppression population carrying denser, behaviorally relevant semantic information. Both populations support semantic integration with distinct temporal dynamics and representational structures. These findings provide representational- and computational-level insights into how the brain integrates information across modalities, revealing unified principles of information processing that link biological and artificial intelligence.

neuroscience↗

bioRxiv2025

Homeostatic Neuronal Plasticity Alters Axon Initial Segment Actin Membrane Skeleton Periodicity

Homeostatic plasticity allows neurons to maintain their activity around a set point, contributing to neuronal network stability over time. Increasing or decreasing neuronal activity not only regulates the levels of ion channels in neurons, but also leads to structural plasticity of the axon initial segment (AIS), the site of action potential initiation. Although previous studies have shown that activity could change the length and position of the AIS along the axon to compensate for changes in neuronal activity, it is currently unknown whether homeostatic plasticity also regulates the periodicity of the AIS actin cytoskeleton. Actin filaments, which are components of the axon plasma membrane skeleton, form periodic rings with a 190-nm spacing. Here, we examined whether the integrity of the actin ring periodicity at the AIS is plastic, depending on prolonged changes in neuronal activity. To induce AIS homeostatic plasticity, we either increased neuronal activity chronically by blocking the AIS enriched Kv7 voltage-gated potassium channels with XE991 or chronically decreased it by using the pan-Kv7 channel opener retigabine (RTG), or alternatively, the voltage-gated sodium channel blocker TTX at different neuronal maturation stages (DIV10 and DIV16). We found that prolonged exposure to XE991 relocated AIS away from soma and disrupted the periodicity of actin rings at DIV10. However, the actin ring periodicity remained unaffected at DIV16. In comparison, long-term treatment with RTG or TTX induced relocation of AIS towards the soma and reduction in AIS length, respectively. In parallel, RTG and TTX disrupted the actin ring periodicity at both developmental stages. These observations suggest that homeostatic plasticity not only changes the AIS position and length, but it could also modulate the periodicity of the AIS actin membrane skeleton, raising the possibility that the mechanical properties of the AIS are also plastic. Statement of significanceHomeostatic plasticity allows neurons to maintain their activity around a set point, contributing to neuronal network stability over time. Although previous studies have shown that activity could change the length and position of the AIS along the axon to compensate for changes in neuronal activity, it is currently unknown whether homeostatic plasticity also regulates the periodicity of the AIS actin cytoskeleton. Here, using super-resolution microscopy, we show that either blocking or activating Kv7 channels could disrupt the periodicity of actin depending on the maturation stage of cultured neurons. In comparison, blocking voltage-gated sodium channels disrupted the actin ring periodicity independent of the age of neurons. These observations suggest that homeostatic plasticity also modulates the periodicity of the AIS actin cytoskeleton.

biophysics↗

bioRxiv2025

A Genome-Based Pipeline for Digital Siderophore Typing in Pseudomonas Iron-Interaction Network

Siderophores are key mediators of microbial interactions, especially in iron-limited environments. While traditional experimental methods for siderophore typing are time-consuming and low-throughput, we present a genome-based pipeline for high-throughput digital siderophore typing in Pseudomonas. Our approach integrates profile Hidden Markov Models (pHMMs), substrate-specific motif identification, and co-evolutionary analysis to predict both the structure of pyoverdines and their corresponding uptake receptors from any given Pseudomonas genome. By this approach, we developed pHMM from 94 previously defined receptor groups and validated their accuracy and robustness across 14,230 Pseudomonas genomes. Application of our method to this large dataset demonstrated the potential of our algorithm for identifying both novel "lock-key" receptor groups and previously uncharacterized pyoverdine structures. Notably, our pipeline corrected long-term misclassifications in classical strains and proposed a new reference for the canonical Group III pyoverdine. Furthermore, interaction network analysis supports the observation of distinct siderophore utilization patterns between pathogenic and non-pathogenic strains. This standardized, user-friendly platform offers a robust tool for annotating siderophore behaviors in Pseudomonas and demonstrates the potential of digital siderophore typing in exploring iron-mediated ecology across microbes. Impact statementIron is vital for microbes. In most environments, they secrete diverse siderophores to scavenge iron. The types of siderophores a strain produces and uptakes shape its interactions, from cooperation to cheating and competition; characterizing this is called "siderophore typing." While traditional methods are limited by experimental capacities, our genome-based digital pipeline revolutionizes the process by predicting siderophore structures and receptor types directly from genomes, enabling large-scale analysis of 14,230 Pseudomonas strains. The results reveal novel groups, correct historical misclassifications, and link patterns to pathogenicity, providing a standardized software for ecological studies, antibiotic design, and bioremediation.

microbiology↗

bioRxiv2025

Hybrid yak-cattle in situ conservation via interspecies somatic cell nuclear transfer at ultra-high-altitude region

Pien-niu, the hybrid offspring of yak (Bos grunniens) and domestic cattle (Bos taurus), possess exceptional adaptability to ultra-high-altitude environments of the Qinghai-Xizang Plateau. In situ conservation is of special significance for ultra-high-altitude region because the offsprings need to possess the ability to adapt to the unique environment. The present study was to clone Pien-niu in Xizang via interspecies somatic cell nuclear transfer (iSCNT) to practice in situ conservation of large animal at ultra-high-altitude region. Ear fibroblast cells were isolated from Pien-niu at Qushui Experimental Station (3650m above sea level), an animal live conservation farm at Xizang, and used as iSCNT donor cells. The iSCNT blastocysts were transferred into the oviduct of surrogate Pien-niu which are maintained at Qushui Experimental Station. A live cloned Pien-niu calf was born on May 12, 2025 and keeps healthy till now. Results of short tandem repeat analysis revealed that the microsatellite loci of cloned calf were completely matched with that of donor fibroblast cells. The successful cloning of Pien-niu can provide a paradigm for in situ germplasm conservation via iSCNT at ultra-high-altitude region.

zoology↗

bioRxiv2025

Identification of mitochondria and macrophage activation related hub genes in sarcopenia

BACKGROUNDTo explore hub genes and pathways related to sarcopenia progression associated with mitochondria and macrophage activation. METHODSGEO datasets GSE8479, GSE1428, and GSE136344 were obtained based on GEO database. MRGs and MARGs were acquired. Thereafter, GO, KEGG, GSEA and PPI analysis were implemented. Later, pooled GEO datasets (Combined Datasets) were further obtained to construct the sarcopenia diagnostic model and sarcopenia subtypes. RESULTSA total of 62 M&MARDEGs were finally identified. There were altogether 9 model genes incorporated into the multifactorial regression model. Immunoinfiltration analysis revealed low scores of M&MARDEGs in the samples with sarcopenia. For macrophage activation in sarcopenia samples, most immune cells were strongly correlated in LowScore group (r = -0.707, p < 0.05). Many immune cells in Mitochondria & Macrophage Activation (HighScore) group were strongly correlated with each other (r = -0.661, p < 0.05). CONCLUSIONScreening key genes for sarcopenia associated with mitochondrial and macrophage activation in this study assists in understanding the pathogenesis of sarcopenia and providing new targets for intervention.

bioinformatics↗

bioRxiv2025

MedSAGE: Bridging Generative AI and Medicinal Chemistry for Structure-Based Design of Small Molecule Drugs

While generative AI is transforming the de novo design of proteins, its effectiveness for structure-based design of small molecules remains limited. Current methods, including diffusion models, often produce small molecules with difficult-to-synthesize structures, poor medicinal chemistry properties, and limited target selectivity. To address these limitations, we introduce MedSAGE, a novel generative AI framework that adapts diffusion models specifically for de novo small-molecule design. Rather than using atoms or strings, we develop a novel representation for generating molecules using fragments relevant for medicinal chemistry. Chemical and geometric information characterizing these fragments is embedded in a smooth and interpretable latent space. We also develop an algorithm to optimize the connectivity between generated fragments while preserving chemical validity and synthesizability. In a benchmark of multiple methods across 25 therapeutically relevant protein targets, MedSAGE achieved state-of-the-art performance, producing synthesizable, drug-like molecules with predicted affinity and selectivity closely matching known drugs and drug candidates. Compared to large-scale virtual screening, MedSAGE produced molecules with high predicted affinity over 100 times more efficiently. Our results demonstrate that MedSAGE is already practically useful and paves the way for next-generation tools in structure-guided drug design.

biophysics↗

bioRxiv2025

Development and application of a genotyping by target sequencing SNP array panel in Salix suchowensis

Salix suchowensis is an important species of Salix, known for its rapid growth property and wide application in environmental construction, ecological restoration, wicker production, and biomass energy production. Due to its significance as a sustainable biological resource, S. suchowensis has been the centre of intensive breeding. However, rapid improvement of growth and biomass has been hindered by a lack of genomic resources. To address this limitation, we designed a genotyping by target sequencing SNP array panel to facilitate efficient genotyping. Using whole-genome resequencing data, a total of 39,076 SNPs were selected for the array panel, consisting of trait-associated SNPs, intragenic SNPs, and intergenic SNPs. This panel was validated by genotyping 550 new samples, demonstrating high call rates and effective capture of the population structure. Genome-wide association analysis identified 72 SNPs associated with plant height and ground diameter. Additionally, the array panel shows a high potential for genomic selection, with high prediction accuracy for various traits. These results highlight the efficiency of this panel in capturing genomic variations that are highly valuable for future genetic research and breeding applications.

genetics↗

bioRxiv2025

An embryonic artery-forming niche reactivates in pulmonary arterial hypertension

Developmental programs that orchestrate cell fate and tissue architecture during organogenesis can cause disease when reactivated in adults. Here we identify a population of endothelial cells (ECs) defined by the pioneer factor early B cell factor 1 (EBF1) that controls both pulmonary artery (PA) morphogenesis and pulmonary arterial hypertension (PAH). During embryonic development, the PA emerges from an endothelial niche harbored within the vascular plexus, where Aplnr+ endothelial progenitors give rise to both arterial ECs and EBF1+ ECs. Rather than directly incorporating into the PA intima, EBF1+ ECs control the branching and maturation of the PA tree through paracrine vasculotrophic signals that direct plexus expansion, arterialization, and mural cell recruitment. Although essential for development, most EBF1+ ECs disappear upon completion of PA morphogenesis. In adult PAH, vascular injury reactivates this developmental program: normally quiescent general capillary ECs re-enter the cell cycle and differentiate into arterial ECs and EBF1+ ECs, reconstituting this artery-forming niche in a maladaptive reprise. Unlike their transient embryonic counterparts, EBF1+ ECs persist within neointimal lesions and express vasculotrophic signals associated with pathological PA remodeling. Capillary-restricted Ebf1 induction combined with endothelial injury recapitulates this program, driving neo-arterialization, neointimal formation, and severe PAH. Conversely, endothelial-targeted AAV-mediated Ebf1 knockdown achieves complete protection in a preclinical model of disease, demonstrating that endothelial EBF1 is necessary for PAH pathogenesis. These findings demonstrate that reactivation and persistence of a transient embryonic artery-forming niche in adulthood can promote pathological vascular remodeling and PAH.

developmental biology↗

bioRxiv2025

Tracing Siderophore Precursors to Primary Metabolism for Ecological Applications

Microbial fitness depends on balancing between primary metabolism supporting basic survival, and secondary metabolism producing metabolites for environmental adaptation. These two systems are interconnected, with most secondary metabolites deriving from primary metabolic precursors. However, systematic frameworks for studying their relationships across diverse microbes remain limited. Using siderophores--iron-chelating secondary metabolites crucial for microbial competition--as a model, we developed a stepwise "siderophore-monomer-precursor-pathway analysis" framework to trace the biosynthetic connections from siderophore structures to primary metabolism. We applied this framework to an expanded SIDERITE database containing 1018 siderophore structures. To demonstrate practical applications, we identified specific precursors utilized by the beneficial rhizobacterium Bacillus amyloliquefaciens but not by the plant pathogen Ralstonia solanacearum. Supplementing these precursors under iron-limited conditions enhanced both siderophore production in B. amyloliquefaciens and its inhibitory activity against R. solanacearum. This work establishes a direct link between primary metabolism and siderophore-mediated microbial interactions, offering new strategies for pathogen suppression through targeted metabolic interventions.

biochemistry↗

bioRxiv2025

Genetic architecture of the S-locus supergene revealed in a tetraploid distylous species

SummaryO_LIHeterostyly is a polymorphic floral adaptation controlled by supergenes and maintained in populations by disassortative mating. The molecular basis of distyly has been investigated in several unrelated families. Previous studies have been limited to diploid species and have not included Rubiaceae, which has the highest number of heterostylous species. C_LIO_LIHere, we investigate the genetic architecture of tetraploid Schizomussaenda henryi (Rubiaceae) to identify candidate style-length genes, evidence for hemizygosity and the potential role of gene duplication in the evolution of the S-locus. Chromosome-level genome assemblies and transcriptomic approaches identified the S-locus region comprised of four hemizygous genes. C_LIO_LIThe candidate gene SchzAUX22 may regulate style length and filament growth by acting in the auxin signaling pathway. Comparative studies of the two sub-genomes of S. henryi indicated strong similarities and no significant sub-genome dominance, as expected from autotetraploidy. Evidence from haplotype-resolved assemblies of a short-styled plant indicated that it possessed the ssSS genotype, consistent with autotetraploidy, which was estimated to have originated [~]3.6 Mya. Analysis of Ks values between S-locus genes and their paralogs indicated that the S-locus likely originated through stepwise duplication. C_LIO_LIOur study provides comprehensive genomic analysis of distyly in a polyploid and demonstrates that despite whole genome doubling the S-locus supergene remains intact and functional as an outbreeding mechanism. Our results contrast with many other heterostylous lineages where polyploidy is associated with breakdown of the polymorphism and transitions to self-fertilization. C_LI

plant biology↗

bioRxiv2025

Sidero-Mining: Systematic Extraction of Siderophore Biosynthetic Information Using Large Language Models

Siderophores are central mediators of microbial iron acquisition, competition, and ecological adaptation, yet their biosynthetic diversity remains difficult to resolve across species because existing sequence-based BGC comparison is strongly constrained by phylogenetic background. Here we combine large-language-model-assisted literature mining, functional-space comparison, and genome-scale analysis to resolve the global organization of siderophore biosynthesis across bacteria. We first built SideroBank, a manually curated cross-species benchmark of siderophore biosynthetic gene clusters (BGCs), and used it to show that many identical products recur across distant taxa whereas the corresponding BGCs often fail to cluster in sequence space. We then developed BGC Block Aligner, which compares BGCs as ordered systems of functionally meaningful blocks and thereby converts comparison from sequence space to functional space. Applied to 97,432 bacterial genomes, this framework produced the Siderophore Atlas, revealing that siderophore synthesis is a remarkably pervasive trait encoded by over 60% of the analyzed genomes, with certain clusters being the most widely disseminated secondary metabolites across the bacterial domain. This global landscape suggests that the adoption of specific biosynthetic strategies is predominantly driven by ecological lifestyle rather than strict phylogenetic relatedness. Furthermore, a stark macro-evolutionary dichotomy was observed between the continuous structural diversification of NRPS pathways and the standardized, HGT-driven dissemination of NIS systems, linking functional-space genomics to the global ecology and evolution of siderophore biosynthesis..

bioinformatics↗

bioRxiv2025

Evolution of chronic lymphocytic leukemia after allogeneic stem cell transplant

Allogeneic stem cell transplant (alloSCT) for patients with relapsed/refractory chronic lymphocytic leukemia (CLL) can result in cure in some patients. Analogous to chemotherapy and targeted therapy, we hypothesized that allogeneic cellular immunotherapies, including alloSCT and donor lymphocyte infusion (DLI), would impact malignant evolution through the application of selective immunologic pressure with reciprocal changes in the T cell compartment. We tested a cohort of 24 patients treated with HLA-matched alloSCT +/- DLI, two mediators of the graft versus leukemia (GVL) effect. Comparison of pre-alloSCT samples revealed that a key difference between responders (n=13) and non-responders (n=11) is the cellularity of leukemic cells. We further mapped mutational trajectories of tumor cells by whole exome sequencing (WES) of sort-purified CLL in 11 post-transplant relapsed patients and found evidence of subclonal leukemic evolution in 8/11 patients after nonmyeloablative human leukocyte antigen (HLA)-matched alloSCT. Different patterns of CLL evolution were observed, and these changes included putative CLL drivers in every case. To investigate the presence of immune-related variants in patients, we collected 19 T cell co-culture CRISPR datasets and identified the top positive and negative regulators of cancer cells response to T-cell-dependent killing. We found that most mutations linked to T-cell killing emerged after allo-SCT treatment, suggesting that selective pressures from the GVL effect may drive the evolution of these mutations. Together, these data identify cellular homogeneity as a key biomarker for susceptibility to GVL-driven immunity in CLL and illustrate how the leukemic cells further evolve to evade immunosurveillance. SIGNIFICANCEThe impact of allogeneic stem cell transplant (alloSCT) on subclonal leukemia evolution remains poorly understood. By performing whole exome sequencing (WES) on pre- and post-alloSCT patient samples, we reveal different patterns of CLL evolution and potential immune-related driver genes influencing CLL relapse and refractory disease post-alloSCT.

cancer biology↗

bioRxiv2025

Evolutionary trajectories of immune escape across cancers

Immune escape is a critical hallmark of cancer progression and underlies resistance to multiple immunotherapies. However, it remains unclear when the genetic events associated with immune escape occur during cancer development. Here, we integrate functional genomics studies of immunomodulatory genes with a tumor evolution reconstruction approach to infer the evolution of immune escape across 38 cancer types from the Pan-Cancer Analysis of Whole Genomes dataset. Different cancers favor mutations in different immunomodulatory pathways. For example, the antigen presentation machinery is highly mutated in colorectal adenocarcinoma, lung squamous cell carcinoma, and chromophobe renal cell carcinoma, and the protein methylation pathway is highly mutated in bladder transitional cell carcinoma and lung adenocarcinoma. We also observe different timing patterns in multiple immunomodulatory pathways. For instance, mutations impacting genes involved in cellular amino acid metabolism were more likely to happen late in pancreatic adenocarcinoma. Mutations in the glucocorticoid receptor regulatory network pathway tended to occur early, while mutations in the TNF pathways were more likely to occur late in B-cell non-Hodgkin lymphoma. Mutations in the NOD1/2 signaling pathway and DNA binding transcription factor activity tended to happen late in breast adenocarcinoma and ovarian adenocarcinoma. Together, these results delineate the evolutionary trajectories of immune escape in different cancer types and highlight opportunities for improved immunotherapy of cancer. SignificanceDespite its critical role in cancer progression, the evolution of immune escape is poorly understood. We integrate functional genomics and tumor evolution reconstruction and infer immune escape trajectories across cancer types. Our results have important implications for developing biomarkers for immunoprevention and treatment strategies for immune escape of cancer.

evolutionary biology↗

bioRxiv2025

Integrated single-cell analyses of affinity-tested B-cells enable the identification of a gene signature to predict antibody affinity.

Advancements in single-cell technologies and deep sequencing have revealed the vast B-cell repertoire arising from immunisation, enhancing the number of antibodies available for testing. However, selecting the highest affinity antibodies from many sequences is not a straightforward feat, as mechanisms sustaining affinity maturation and related markers remain under-studied. Here, we generated datasets of antigen-specific B-cells after mouse immunisation as well as re-analysed public data to identify a novel transcriptomic signature, "High Signature" (HS), with predictive power for high-affinity antibodies. HS, derived by integrating antibody sequences, gene expression, and affinity measurements, enabled sub-nanomolar affinity antibody selection without sequence pre-analysis. Notably, HS-expressing B-cells were 2.5 times more likely to yield high-affinity antibodies than randomly picked cells. Mechanistically, we identified RUVBL2, an AAA+ ATPase, as a primary HS modulator, suggesting its involvement in affinity maturation. Furthermore, HS applied to human PBMC data enriched high-affinity antibody expression, underscoring its potential in antibody discovery.

immunology↗

bioRxiv2025

Catalytic degradation of circulating targets with FcRn-mediated cycling LYTACs

Circulating proteins are common targets for the discovery of occupancy-based inhibitors including monoclonal antibodies. Effective inhibition of target pathogenicity with blocking approaches, however, is often challenged by target parameters that lead to insufficient occupancy and/or incomplete pharmacology limited by only single site binding. Extracellular targeted protein degradation approaches, such as lysosomal targeting chimeras (LYTACs), offer an opportunity to minimize these challenges by an event-driven mechanism that selectively, thoroughly and irreversibly eliminates drivers of disease. First generation LYTACs, designed to traffic to the lysosome, show limited durability since the therapeutic is degraded along with the target protein of interest. Here we describe cataLYTACs, which overcome this limitation by combining stabilized asialoglycoprotein (ASGPR) ligands, pH-sensitive target binding and recycling via the neonatal Fc receptor (FcRn). These cataLYTACs degraded superstoichiometric levels of a target protein, IgE, in vitro and demonstrated deep and sustained clearance of human IgE in mouse models. In non-human primates, cataLYTACs resulted in >98% clearance of circulating endogenous IgE for 2 weeks and outperformed the standard of care blocking antibody, omalizumab (Xolair(R)), in both free IgE elimination and duration of action. CataLYTACs represent a new therapeutic modality for a wide range of disease states driven by circulating factors, with the potential for superior efficacy and duration of action compared to traditional inhibitors.

cell biology↗

bioRxiv2024

An A-T Hoogsteen base pair in a naked DNA hairpin motif: A Protein-Recognized Conformation

In duplex DNA, A-T and G-C form Watson-Crick base pairs, and Hoogsteen pairing only dominates upon protein binding or DNA damage. Using NMR, we show that an A-T Hoogsteen base pair previously observed in crystal structures of transposon DNA hairpins bound to TnpA protein forms in solution even in the absence of TnpA. This Hoogsteen base pair, located adjacent to a dinucleotide apical loop, exists in dynamic equilibrium with a minor Watson-Crick conformation (population [~]11% and lifetime [~]55 {micro}s). Extending the apical loop to three residues inverted the equilibrium, making Watson-Crick the dominant state and the Hoogsteen conformation recognized by TnpA a minor state (population [~]14% and lifetime [~]28 {micro}s). The propensity for Hoogsteen pairing depended on apical loop residues, which form contacts directly or indirectly stabilizing the Hoogsteen conformation. A structure survey did not reveal Hoogsteen pairing near RNA apical loops making them unique to DNA. Our results demonstrate that Hoogsteen can be the dominant state even in naked unmodified duplex DNA and identify 5-CTT(T/C)AG-3 as a DNA-specific apical loop motif stabilized by Hoogsteen pairing. Hoogsteen base pairs may be prevalent in DNA hairpins forming during replication and transcription, with broad implications for the genomic landscape.

biochemistry↗