Biology subjects

Xie, J.

Publications and source records attributed to Xie, J..

At least 73 records · Page 4Linked to original sources

bioRxiv2025

Pentoxifylline, a Non-Antibiotic Drug, Promotes Adaptation of Clinical Isolates of Staphylococcus aureus via Modulating c-di-AMP Signaling

This study investigated how Staphylococcus aureus adapts under pentoxifylline (PTX) therapy through analyzing three phylogenetically related isolates (L1, L2, L3) from a bacteremia patient. Whole genome sequencing revealed L1 contained a 2400-bp insertion disrupting nupC, while L3 harbored mutations in the anti-Shine-Dalgarno sequences of 16S rRNA. Each isolate evolved distinct mechanisms to reduce c-di-AMP levels, accompanied by changes in survival ability and virulence. Molecular analysis demonstrated PTX noncompetitively inhibits GdpP phosphodiesterase, directly modulating cyclic diadenosine monophosphate (c-di-AMP) signaling. Our findings provide novel insights into how non-antibiotic medications shape bacterial adaptation through second messenger modulation, highlighting the complex trade-offs between stress resistance and fitness in clinical settings. ImportanceThis study reveals how pentoxifylline, a non-antibiotic drug, drives Staphylococcus aureus adaptation by modulating c-di-AMP signaling. Our findings highlight the unintended consequences of non-antibiotic medications on bacterial evolution, offering new insights for clinical treatment strategies to mitigate resistance development. HighlightsO_LIPTX noncompetitively inhibits GdpP, modulating bacterial c-di-AMP signaling C_LIO_LIS. aureus evolves distinct mechanisms to reduce c-di-AMP under PTX pressure C_LIO_LINon-antibiotic medications significantly shape bacterial adaptive trajectories C_LI

microbiology↗

bioRxiv2025

Mycobacterium tuberculosis m4C DNA methyltransferase Rv3204 promotes mycobacteria survival under oxidative stress

Reactive oxygen species (ROS) inflict cellular damage yet are pivotal mediators of signaling pathways. Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), persists as a major global health threat, partly due to its capacity to neutralize host-derived ROS toxicity. While DNA methylation deficiency is known to attenuate Mtb virulence, the specific role of DNA methyltransferases in mycobacterial survival under oxidative stress remains poorly defined. Here, we demonstrate that the mycobacterial protein Rv3204 functions as an N4-methylcytosine (m4C) DNA methyltransferase. Deletion of the Rv3204 homolog (Ms_1939) in Mycobacterium smegmatis significantly impaired bacterial survival upon rifampicin exposure. This phenotype was associated with heightened intracellular ROS accumulation and a failure to upregulate transcription of ROS detoxification genes. Furthermore, the mutant exhibited downregulated expression of DNA repair genes and increased susceptibility to fluoroquinolone antibiotics (norfloxacin, ofloxacin). Crucially, the Ms_1939 deletion strain displayed elevated levels of DNA damage. To our knowledge, this is the first study establishing a direct link between an m4C DNA methyltransferase and ROS homeostasis in mycobacteria. Our findings identify Rv3204 as a potential novel therapeutic target for modulating ROS sensitivity in M. tuberculosis. ImportanceMycobacterium tuberculosis, the causative agent of tuberculosis, remains a major global health threat due in part to its ability to withstand host-derived oxidative stress. This study identifies Rv3204 as a novel N4-methylcytosine DNA methyltransferase essential for mycobacterial survival under oxidative stress. We demonstrate that deletion of Rv3204 homolog in M. smegmatis leads to elevated intracellular ROS, impaired transcriptional activation of antioxidant and DNA repair genes, increased DNA damage, and heightened susceptibility to fluoroquinolone antibiotics. Our findings establish a critical link between epigenetic regulation via m4C methylation and ROS homeostasis in mycobacteria--a relationship previously unexplored. This work not only advances our understanding of bacterial epigenetic mechanisms in stress adaptation but also positions Rv3204 as a promising target for novel anti-tuberculosis strategies aimed at disrupting redox balance and enhancing antibiotic efficacy. DATA summaryRaw data files have been deposited in the National Center for Biotechnology Information (NCBI) Gene Expression Omnibus (GEO) under accession number GSE139646 (https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE139646).

genetics↗

bioRxiv2025

The Rab5 effector Rabankyrin-5 mediates endosomal fusion and trafficking of Human Papillomavirus during early entry

The fusion of newly formed early endosomal vesicles after endocytosis is a crucial step in viral infection. It facilitates the transition of many viruses from viral internalization to downstream intracellular trafficking within the endosomal network, ultimately enabling their delivery to intracellular replication sites. Despite its significance, the molecular mechanisms regulating the fusion of these vesicles remain poorly understood. In this study, we show that Rabankyrin-5, a Rab5 effector, is essential for the fusion of human papillomavirus (HPV)-containing early endosomes during viral entry. Additionally, Rabankyrin-5 acts as a dynein adaptor, directly binding both the HPV minor capsid protein L2 and the dynein motor complex to link virus-carrying early endosomes to the dynein transport machinery, thereby promoting virus movement along microtubules. These dual functions enable the coordinated integration of endosomal fusion with microtubule-based transport during the early stages of viral entry.

microbiology↗

bioRxiv2025

CD38⁺ Endothelial Remodeling Defines Spatially Diverse Vasculopathy Programs in Rapidly Advancing Oral Inflammation

Oral inflammatory diseases affect nearly half of the global population. Among them, newly defined peri-implantitis and high-grade periodontitis represent rapidly advancing inflammatory disease types, marked by relatively rapid tissue destruction. Despite their prevalence, the cell mechanisms and spatial architecture driving this severity remain poorly understood. Focusing first on peri-implantitis versus low- and moderate-grade periodontitis, we applied microbial profiling, single-cell RNA sequencing (scRNA-seq), and spatial proteomics (sp-proteomics) to uncover shared pathogenic programs linked to accelerated niche breakdown. Furthermore, to preserve spatial fidelity, each tissue was anatomically orientated along the tooth- or implant- epithelial interface, analogous sites of disease origination. Laser capture microdissection followed by microbiome analysis of unique tissue compartments revealed reduced bacterial load and diversity in peri-implantitis stroma. We then expanded our version-1 Human Periodontal Atlas by integrating newly generated peri-implantitis scRNAseq data (36-total samples; 121395-cells), revealing widespread transcriptional alterations, including oxidative stress, hypoxic, and NAD+ metabolism-associated signatures, primarily in a subpopulation of TNFRSF6B+/ICAM1+post-capillary venules. We then performed high-resolution sp-proteomics (15-total samples; 337260-cells) and analyzed VEC states and associated neighborhoods via AstroSuite using newly developed tri-wise spatial analysis. This revealed CD34+-VEC loss and CD38+-VEC expansion almost exclusively in peri-implantitis. We extended this analysis to high-grade periodontitis. Mucosal biopsies from four lesion-affected and four unaffected sites within the same individuals (1:1 matched; 8-samples; 225137-cells) again demonstrated spatially restricted CD38+-VEC remodeling exclusively in affected tissues, with similar vasculopathy front patterning. The findings nominate spatially distinct vasculopathy patterning as a hallmark of rapidly advancing oral inflammation and a targetable therapeutic axis.

immunology↗

bioRxiv2025

Systemic Inflammation Modulates Clearance and drives Extra-Hepatic Distribution of Extracellular Vesicles

Extracellular vesicles (EVs) are promising vehicles for targeted therapeutic delivery, capable of encapsulating and transporting biomolecules to specific cells and tissues. Given that inflammation is central to many acute and chronic diseases, understanding EV biodistribution under inflammatory conditions is essential for therapeutic optimization. This study examines how acute systemic inflammation influences EV biodistribution, clearance, and plasma half-life, with a focus on the role of macrophages and their polarization states. Using a lipopolysaccharide (LPS)-induced inflammation model in wild-type mice and bioluminescent and fluorescent labelling of EVs, we observed that inflammation extends the plasma half-life of EVs by over 600-fold within 2 hours and 900-fold at 24 hours post-administration, leading to significant enrichment in inflamed organs, particularly the liver and spleen. Enhanced accumulation in specific tissues translated to increased targeting of immune- and epithelial cells within those organs, with notable uptake by hepatocytes in the liver. This prolonged half-life was attributed to the altered EV protein corona in inflamed tissues, which facilitates cellular association. These findings underscore the complex dynamics between EVs and immune cells under inflammatory conditions and provide critical insights for advancing EV-based therapies in chronic inflammatory diseases.

bioengineering↗

bioRxiv2025

DIFFERENTIAL ROLES OF RAD18 IN REPRESSING CARCINOGEN- AND ONCOGENE-DRIVEN MUTAGENESIS IN VIVO

The DNA repair protein RAD18 activates Y-family Trans-Lesion Synthesis (TLS) DNA polymerases that are DNA damage-tolerant and potentially error-prone. RAD18 is also frequently overexpressed and pathologically activated in cancer cells. However, the extent to which RAD18 shapes cancer genomes and impacts tumorigenesis is unclear. Therefore, we tested the effect of Rad18 status on chemically-induced and oncogene-driven tumorigenesis. In a chemically-induced oral carcinogenesis model, acute (2-16 days) 4NQO-treatment induces expression of Rad18 and TLS polymerase mRNAs in mouse oral epithelial cells prior to emergence of oral squamous cell carcinomas (OSCCs). Chronic (8 week) 4NQO-treatment leads to onset of oral tumors that is accelerated in Rad18-/- mice when compared with Rad18+/+ animals. Analysis of OSCC exomes reveals increased levels of G(C)>T(A) transversions in Rad18-/- tumors when compared with Rad18+/+. Therefore, Rad18 promotes error-free bypass of 4NQO-induced DNA lesions and suppresses 4NQO-induced oral carcinogenesis. In a KrasG12D-induced lung carcinogenesis model, Rad18-deficiency did not affect rates or incidence of oncogene-induced lung tumors or mutations. Taken together, we demonstrate that Rad18 has context-specific tumor-suppressive activity. Given the prevalence of 4NQO-like environmental exposures, RAD18 is highly likely to shape human cancer genomes and perhaps influence other aspects of the tumorigenic process.

cancer biology↗

bioRxiv2025

Specificity of Aberrant Exons in a Saturated Background of Differentially Expressed Exons

Determining the maximal specificity of aberrant exons from multifactorial disease tissues in a whole body background could provide insights into the exon origin as well as potential targets of diagnosis or therapy, but it remains a challenging task. For this purpose, we obtained a saturated list of differentially expressed exons (DEXs) from our independent reference human exome extracted from 56 normal tissues by DEXSeq. We found that the DEXs comprised the majority of the reference exome and that 99.4% of cancer-specific exons relative to paired normal tissues fell within the DEX list, consistent with the ectopic expression of the majority of aberrant exons. We then screened over seven thousand pathogenic single nucleotide variants (SNVs) in the TCGA and COSMIC databases by SpliceAI. The analysis identified over three hundreds of highly confident, mostly somatic SNV-specific splicing events and/or novel exonic fragments in five types of adenocarcinomas. Interestingly, these events are all associated with cis-acting mutations in tumor suppressor genes, particularly in TP53 with an antigenic novel peptide. This revelation of the DEX exome dominance and non-specificity of nearly all aberrant exons not only reshapes our understanding of the normal human exome by highlighting its mainly variable over constitutive exons, but also illuminates the path through cis-acting somatic and pathogenic SNVs to identify genuine cancer-specific exonic fragments that are absent in any normal tissues, beyond neo-exon junctions. This path holds promise for identifying novel peptide fragments for antigens in holistic cancer treatments including vaccination and immunotherapies.

cancer biology↗

bioRxiv2025

Beach sand beneath our feet: an overlooked reservoir of antibiotic resistance genes and pathogens, revealed by metagenomic evidence from Qingdao's recreational beaches

Coastal beach environments, especially those with heavy tourist activity, represent a dynamic interface between terrestrial and marine microbiomes. However, beach sand is rarely considered in surveillance of antibiotic resistance. In this study, we combined 16S rRNA gene sequencing and shotgun metagenomics to characterize microbial communities and antibiotic resistance genes (ARGs) at four popular recreational beaches in Qingdao, China. We show that beach sands harbor highly diverse bacterial communities with significantly greater richness than adjacent seawater. Beach sand near sewage discharge points had microbial profiles intermediate between raw sewage and open-ocean water, reflecting contributions from both sources. Metagenomic analysis identified a broad "resistome" of over 300 distinct ARGs in these beach and water samples, spanning 33 antibiotic classes and 6 resistance mechanism categories. Notably, the rifampicin resistance gene rpoB2 was the most abundant ARG, and genes conferring resistance to peptide antibiotics were prevalent. Sewage outfalls were found to be major contributors of ARGs, with waste-influenced sand containing a larger and more diverse ARG pool than sand farther from pollution sources. We also detected a high diversity of bacterial virulence factor genes, particularly in sand. Our findings highlight that tourist beaches can serve as reservoirs and mixing zones for antibiotic-resistant and potentially pathogenic bacteria from land-based pollution. This underscores the need to include beach sand in environmental monitoring for antibiotic resistance and to improve wastewater management at recreational coastlines to mitigate public health risks. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=198 SRC="FIGDIR/small/661489v1_ufig1.gif" ALT="Figure 1"> View larger version (84K): org.highwire.dtl.DTLVardef@18705f3org.highwire.dtl.DTLVardef@1979f8forg.highwire.dtl.DTLVardef@16c9029org.highwire.dtl.DTLVardef@6c778d_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2025

Metabolite Interactions Mediate Beneficial Alliances Between Bacillus and Trichoderma for Effective Fusarium Wilt Control

Bacteria-Fungi Interactions play a crucial role in soil nutrient cycling and plant disease suppression. Bacillus and Trichoderma exhibit antagonism when inoculated on laboratory media, global soil sample analysis reveals a positive correlation between these two genera in addition to enhanced plant-pathogen Fusarium oxysporum (FOC) suppression and plant growth promotion. Here, we depict a complexity of interactions in a cross-kingdom consortia of Bacillus velezensis and Trichoderma guizhouense. Transcriptomic profiling revealed that in the presence of fungi, the key stress sigma factor of B. velezensis activates expression of biosynthetic genes for antimicrobial secondary metabolite production. Among these, surfactin induces T22azaphilone production in T. guizhouense that hinders oxidative stress. Both surfactin and T22azaphilone contribute to Bacillus and Trichoderma maintenance in soil in the presence of FOC. Finally, FOC-secreted fusaric acid temporarily inhibits B. velezensis growth while it is efficiently degraded by T. guizhouense. These metabolite-mediated interactions reveal how competing soil microorganisms could form effective alliances that ultimately enhance plant protection against soil-borne pathogens.

microbiology↗

bioRxiv2025

Metagenomic Analysis Reveals Northwest Pacific Ocean as a Reservoir and Evolutionary Hub of Antibiotic Resistance Genes

O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/659680v1_ufig1.gif" ALT="Figure 1"> View larger version (81K): org.highwire.dtl.DTLVardef@139e191org.highwire.dtl.DTLVardef@10834c4org.highwire.dtl.DTLVardef@1c0544aorg.highwire.dtl.DTLVardef@1ddfd8a_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical abstractC_FLOATNO C_FIG Antibiotic resistance genes (ARGs) were identified as a novel type of environmental contaminants. Ocean is thought to be one of the ultimate environments where ARGs gathered. Marine ecosystems represent vast reservoirs of ARGs, yet their dynamics in open-ocean environments remain poorly characterized. Through large-scale metagenomic profiling of the Kuroshio Extension, a hydrographically dynamic region in the Northwest Pacific, we identified a striking enrichment of ARGs (1.81 x 10-3 ppm) at a frontal zone site (S30). The ARG abundance at this site exceeded coastal levels by 90-fold. Notably, multidrug resistance genes dominated this hotspot, with efflux pumps contributing 62% of the resistance mechanisms, a pattern distinct from the target-alteration strategies prevalent in other regions. The site exhibited unique microbial consortia, including pathogenic Acinetobacter (30.2% abundance) carrying clinically critical determinants (blaOXA-23, adeJ). Co-occurrence networks revealed horizontal transfer risks, linking pelagic Sphingobium to terrestrial-derived {beta}-lactamase variants. Crucially, we discovered three novel plasmid-borne resistance genes circulating in >15% of microbial populations, demonstrating open-ocean ARG diversification independent of direct anthropogenic inputs. These findings redefine oceanic frontiers as crucibles of resistance evolution, demanding urgent integration into global antimicrobial stewardship strategies.

microbiology↗

bioRxiv2025

Comparative assessment of co-folding methods for molecular glue ternary structure prediction

Molecular glues (MGs) represent an emerging therapeutic paradigm capable of inducing or stabilizing protein-protein interactions, with broad applications in creating neomorphic interactomes and targeted protein degradation. However, current discovery efforts remain largely confined to experimental screening, while in silico rational design of MGs persists as a formidable challenge. A critical step toward rational design lies in accurate ternary complex modeling. Given the scarcity of such complexes in the Protein Data Bank for training specialized predictive models, we tested the ability of recently developed co-folding models, including AlphaFold 3, Boltz-1, Chai-1, Protenix, and RoseTTAFold All-Atom in building the complex models. We systematically curated a dataset, named MG-PDB, with 221 non-covalent MG-engaged ternary complexes. MGBench were further introduced as a comprehensive benchmark set, which comprises 88 ternary structures excluded from co-folding models training data through rigorous time-based partitioning. Our benchmark results demonstrated that AlphaFold3 achieved the best overall performance among co-folding methods, in terms of both protein-protein interaction interface prediction (50.6% success rate) and MG-protein interaction recovery (32.9% success rate). However, our homology study showed that most of their successful predictions actually stemmed from memorization. Further analysis revealed three phenomena of current co-folding methods for MG ternary structure prediction. Firstly, these methods struggle to accurately model large interaction interfaces. Secondly, their predictive accuracy is notably reduced for domain-domain complexes compared to domain-motif interactions. Lastly, they face specific challenges in modeling MG degrader complexes with sufficient accuracy. We showcased they relied on the existing interaction patterns, and highlighted the need for further improved in novel E3 ligase systems. These findings reveal fundamental gaps in existing methods to learn atomic-level interaction rules for MG-engaged ternary complex modeling. MG-PDB and MGBench provide critical resources and mechanistic insights to advance computational MG discovery. Table of Contents Graphic O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=127 SRC="FIGDIR/small/655997v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@172b19borg.highwire.dtl.DTLVardef@ea4844org.highwire.dtl.DTLVardef@12ea246org.highwire.dtl.DTLVardef@9fb4bc_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

bioRxiv2025

A Compact Base Editor Rescues AATD-associated Liver and Lung Disease in Mouse Models

Alpha-1 antitrypsin deficiency (AATD) is commonly caused by a G-to-A mutation in the SERPINA1 gene (the PiZ mutation). The mutant PiZ AAT protein is sequestered in hepatocytes, causing lung emphysema due to insufficient AAT protein to inhibit neutrophil elastase in the lung. Here we show that a compact adenine base editor (ABE) with an evolved Cas9 nickase derived from Neisseria meningitidis (eNme2.C) can be packaged in a single AAV and correct the PiZ mutation in mouse models of AATD. An all-in-one eNme2.C-TadA8e/guide 2 plasmid achieved approximately 20% on-target editing in PiZ reporter cells. TadA9e, which has a narrower editing window than TadA8e, reduced bystander editing without significantly affecting the on-target edit. In PiZ transgenic mice, eNme2.C-TadA9e AAV showed approximately 23% editing efficiency after 8 weeks and reduced liver disease burden in treated mice. In a new AAT-null;PiZ transgenic mouse model, ABE restored serum levels of AAT to beyond the 570 g/mL therapeutic level. Moreover, ABE treatment was able to significantly correct lung functions in AAT-null;PiZ animals with emphysema. This study demonstrates the feasibility of an eNme2.C-based ABE in a single AAV to treat both AATD-associated liver and lung disease.

bioengineering↗

bioRxiv2025

NanoLoop: A deep learning framework leveraging Nanopore sequencing for chromatin loop prediction

Chromatin loops play a crucial role in gene regulation and cellular function, providing key insights into understanding the three-dimensional structure of the genome and its impact on cellular homeostasis. Nanopore sequencing technology, with its advantages in simultaneously detecting sequences and methylation patterns, brings new opportunities for studying three-dimensional genome structures. We introduce NanoLoop, the first algorithmic framework attempting to predict genome-wide chromatin interactions using Nanopore data. In experiments across four human lymphoblastoid cell lines, NanoLoop demonstrated excellent predictive performance and cross-cell line generalization capabilities. We also discovered four distinct methylation patterns at loop anchors that influence histone modification levels and determine various loop types. NanoLoop further predicted previously uncharacterized long-range chromatin loops, highlighting DNA methylations role in three-dimensional genome regulation and providing new insights into the complex regulatory relationships between epigenetic modifications and three-dimensional genome organization.

bioinformatics↗

bioRxiv2025

A Gentle Introduction to Spatial Transcriptomic Analysis with 10X Visium Data

Spatial transcriptomics (ST) combines single-cell RNA-seq gene expression data with spatial coordinates to provide an accurate, 2D picture of gene expression across a tissue sample. With this technology, we can discover detailed RNA localization, study development, investigate the tumor microenvironment, and create a tissue atlas. Full ST analysis requires several steps, however, as this protocol aims to be a simple introduction to the analysis process, only the foundational steps of clustering, spatially variable gene discovery, and cell-cell communication are presented, focusing on data obtained from the 10X Genomics Visium platform. An expanded protocol with full code is available at https://github.com/j-gillespie-dna/STanalysis.git

bioinformatics↗

bioRxiv2025

Comparative multi-omics profiling of Gossypium hirsutum and Gossypium barbadense fibers at high temporal resolution reveals key differences in polysaccharide composition and associated glycosyltransferases

Among the two allopolyploid cultivated species of cotton, Gossypium barbadense is known for its superior quality fiber compared to G. hirsutum. Length and strength are key determinants of the fiber quality. Although the mature fibers are dried cell walls consisting mainly cellulose, the dynamic remodeling of pectin, xyloglucan, and xylan polysaccharides during fiber growth significantly impact the final fiber quality. Comprehensive knowledge about polysaccharides and their biosynthesis during fiber development of the cultivated species is important for improving fiber quality. In this study, comparative large-scale glycome, transcriptome and proteome profiling were conducted daily on fibers of both cotton species covering critical stages of fiber development spanning primary cell wall synthesis and the transition to secondary wall synthesis. Interspecific comparisons revealed that a delayed accumulation of cellulose content, as well as the occurrence of lower levels and differential compositions of non-fucosylated/fucosylated xyloglucans, homogalacturonans, and highly branched Rhamnogalacturonan-I polysaccharides might be contributing to longer fiber phenotypes of G. barbadense relative to G. hirsutum. Our study also suggests, differential temporal compositions of heteroxylans might contribute to variation in cellulose microfibril arrangement and strength of fiber exists between the two species of cotton. Comparative transcriptomic analysis identified differentially expressed polysaccharide-synthesizing glycosyltransferases that might underlie fiber quality differences between the two species. Transcripts encoding many cell wall localized expansins were more abundant in G. barbadense than in G. hirsutum. Overall, these findings extend our knowledge regarding the molecular factors that contribute to fiber quality and provide insights for targeted cotton fiber improvement. SIGNIFICANCE STATEMENTComparative multi-omics profiling of two major commercial cotton species, Gossypium hirsutum and Gossypium barbadense revealed substantial differences in polysaccharide structures and expressed polysaccharide-synthesizing glycosyltransferases, that potentially contribute to differences in fiber length and strength. The molecular details elucidated in the present study contribute to the goal of improving fiber quality and its commercial value.

plant biology↗

bioRxiv2025

Whole-Proteome Screening and Multi-Modal Profiling of Antigen-Specific CD4+ T Cells at Single-Cell Resolution

Systematic whole-proteome screening and comprehensive profiling of antigen-specific CD4+ T cells are crucial for advancing our understanding of CD4+ T cell immunity, yet such efforts remain technically challenging. Here, we present a high-throughput platform that employs large-scale class II single-chain trimer libraries to detect antigen-specific CD4+ T cells, while simultaneously profiling their antigen specificity, TCR/{beta} sequences, MHC restriction, whole transcriptomes, and patient/timepoint origins at single-cell resolution. We benchmarked SCTs against conventional pMHCs and validated the SCT library-based approach in direct ex vivo identification of antigen-specific CD4+ T cells in healthy donors. We then applied the platform to screen the entire SARS-CoV-2 receptor-binding domain in a longitudinal patient cohort, identifying 2,188 antigen-specific CD4+ T cells and revealing key features that define antigen immunogenicity. Extending to cancer, we performed whole-proteome screening of HPV-16 E6/E7 for TCR repertoire profiling in a precancerous cohort, uncovering functional heterogeneity of HPV-specific TCRs. By integrating high-throughput antigen screening with high-dimensional, multi-modal cellular characterization, our approach offers an unprecedented window into CD4+ T cell immunity across diverse disease contexts and empowers the development of new therapies.

bioengineering↗

bioRxiv2025

Functional relevance of CASP16 nucleic acid predictions as evaluated by structure providers

Accurate biomolecular structure prediction enables the prediction of mutational effects, the speculation of function based on predicted structural homology, the analysis of ligand binding modes, experimental model building and many other applications. Such algorithms to predict essential functional and structural features remain out of reach for biomolecular. Here, we report quantitative and qualitative evaluation of nucleic acid structures for the CASP16 blind prediction challenge by 12 of the experimental groups who provided nucleic acid targets. Blind predictions accurately model secondary structure and some aspects of tertiary structure, including reasonable global folds for some complex RNAs, however, predictions often lack accuracy in the regions of highest functional importance. All models have inaccuracies in non-canonical regions where, e.g., the nucleic-acid backbone bends or a base forms a non-standard hydrogen bond. These bends and non-canonical interactions are integral to form functionally important regions such as RNA enzymatic active sites. Additionally, the modeling of conserved and functional interfaces between nucleic acids and ligands, proteins, or other nucleic acids remains poor. For some targets, the experimental structures may not represent the only structure the biomolecular complex occupies in solution or in its functional life-cycle, posing a future challenge for the community.

biophysics↗

bioRxiv2025

A biGWAS strategy reveals the genetic architecture of the interaction between wheat and Blumeria graminis f. sp. tritici

BackgroundWheat powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt) is one of the most significant diseases affecting global wheat production. Breeding for disease resistance (R) genes against Bgt often follows a boom-bust cycles, where cultivars with effective resistance are widely deployed on an expanding area until virulence emerges in the avirulence (Avr) pathogen population. While extensive effort has been devoted to identifying and cloning R genes, Avr genes remain relatively understudied, limiting our understanding of R-Avr interactions. That said, understanding R-Avr interactions is crucial for developing durable resistance strategies. ResultsWe conducted whole genome sequencing on 245 Bgt isolates collected from major wheat-growing regions in China, identifying 120 genetically unique isolates. Each of these unique isolates was inoculated and phenotyped on a diverse panel of wheat germplasm. Through Genome-Wide Association Analysis (GWAS) in both Bgt and wheat, we identified 65 Avr loci and 251 R loci overlapping with nine and eight cloned Avr or R genes, respectively. On average, each isolate carries eight Avr alleles, ranging from one to 17. Little geographical preference for Avr alleles or their combinations was observed, suggesting that disease resistance breeding against this pathogen should be coordinated at the national level. The level of resistance level is positively correlated with the number of R alleles carried by a wheat line, and the average frequency of an R allele is 2% among the wheat panel, indicating the potential for accumulating R alleles in breeding programs. We mapped 212 R-Avr interactions based on joint GWAS using both plant and pathogen genomes and cross-species epistasis, where a network of interactions was formed between wheat and Bgt. These interactions indicate that pyramiding five major R loci has the potential to confer resistance to half of the Avr loci. As a proof of concept, we successfully verified two previously described R-Avr pairs using tobacco experiments. Furthermore, we provided molecular validation evidence for three new Avr genes, including Bgt-50651, BgtE-5826 and BgtE-20009, and two new R-Avr interactions. Among them, Bgt-50651 interacts with Pm1a, Pm2a, and another unidentified R gene located near the Pm6/Pm52 interval. ConclusionOur study provides a framework for understanding the genetic interaction between plants and pathogens. The discovery of novel R/Avr loci and their complex interaction network underscores the need to integrate crop and pathogen genetic background, particularly the R/Avr allele composition, into breeding program design. These findings have significant implications for developing durable resistance strategies in wheat alongside offering valuable insights into the broader dynamics of plant-pathogen interactions.

genomics↗