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Xu, J.

Publications and source records attributed to Xu, J..

At least 55 records · Page 3Linked to original sources

Extracellular vesicles drive cross-genus mycovirus transmission and suppress two fungal diseases

Mycoviruses are typically transmitted vertically through fungal reproduction or horizontally via hyphal anastomosis, but identical viruses in phylogenetically divergent fungi hint at unknown inter-species transmission mechanisms. Here, we identify fungal extracellular vesicles (EVs) as mediators of cross-genus mycovirus transmission. Using the hypovirulent Botrytis cinerea strain IBc-374 (harboring 16 mycoviruses) as a donor, we show that up to 13 mycoviruses are horizontally transmitted to Sclerotinia sclerotiorum during dual culture or plant co-inoculation, even though these two fungi belong to different genera and are generally considered incapable of hyphal anastomosis. Electron microscopy reveals abundant vesicle structures in IBc-374 hyphae, and nanoparticle tracking analysis showed that the strain secretes >11-fold more EVs than a virus-free strain. RT-PCR detects genomic RNAs of 7 mycoviruses in purified EVs, and the full-length viral genome in EVs was further validated with BcHV5 as example by fluorescence in situ hybridization and RT-PCR. Incubation of protoplast-derived germlings of S. sclerotiorum or B. cinerea with IBc-374 EVs leads to infection by 4-6 donor mycoviruses, demonstrating EV-mediated cross-genus transmission. Injection of mycovirus-carrying EVs into tobacco leaves followed by fungal inoculation also transmits two hypoviruses to both species. Application of IBc-374 hyphal fragment suspension significantly reduces lesion sizes caused by both pathogens on plants, and rescued two pathogens carrying multiple mycoviruses exhibit hypovirulence and impaired growth. Our findings reveal EVs as a cell-free vector that bypasses vegetative incompatibility, providing a mechanistic basis for cross-species viral spread and opening avenues for EV-based virus cocktails to control multiple fungal diseases. IN BRIEFWu et al. discover that fungal extracellular vesicles (EVs) can package and transmit multiple mycoviruses across genera from Botrytis cinerea to Sclerotinia sclerotiorum. EV-mediated delivery overcomes vegetative incompatibility barriers and reduces disease caused by both fungal pathogens, offering a cell-free strategy for mycovirus-based biological control.

microbiology↗

Destabilization of intratumor Tregs by CTLA-4 engagement confers anti-CTLA-4-driven immunotherapy

Immune checkpoint inhibitors (ICI) that are antibodies against CTLA-4 have achieved therapeutic effects on multiple types of cancers 1-4, but the mechanisms underlying the therapy remain incompletely understood. In contrast to the initial theory that the antibody blockades CTLA-4 on T cells is of central importance, it has recently been demonstrated that selective reduction of CD4+Foxp3+ regulatory T cells (Tregs) in the tumor microenvironment by the antibody plays a key role in the anti-tumor effects5-8, although this phenomenon remains under debate in human patients9-12. We show here that anti-CTLA-4 antibody engages CTLA-4 in Tregs specifically in the tumor tissues to reduce their stability and survival and weaken their suppressive function through upregulating TGF-{beta} signaling. This leads to the antibody-mediated - upregulation of CD4+ and CD8+ effector T cell anti-tumor immunity and consequently cancer immunotherapy. Specifically, anti-CTLA-4 antibody directly stimulates CTLA-4 in intratumor Tregs to enhance their TGF-{beta} receptor I (T{beta}RI)-mediated TGF-{beta} signaling13. This results in reduction of IL-2 receptor CD25 expression and downregulation of lactate metabolism in intratumor Tregs to reduce their stability and survival 14-16, and also compromises their suppressive function by inhibiting Foxp3 expression. This activity requires high levels of CTLA-4 expression in the intratumor Tregs and the presence of antibody Fc receptors in the tumor tissues. Strikingly, deletion of T{beta}RI specifically in Tregs completely prevents the reduction of intratumor Tregs and abrogates the anti-CTLA-4-mediated cancer immunotherapy. In contrast to intratumor Tregs, anti-CTLA-4 antibody treatment blocks CTLA-4 in the intratumor CD4+ Foxp3- and CD8+ T effector cells and in the peripheral Tregs to decrease their T{beta}RI expression and increase their expansion due to their relatively low levels of CTLA-4 in the same tumor bearing mice. Significantly, the engagement of CTLA-4 by anti-human CTLA-4 antibody (ipilimumab) also upregulates TGFBR1 but decreases Il2RA expression and lactate metabolism in human Tregs in vitro and in humanized mice in vivo, leading to suppression of tumor progression. We have provided additional mechanism underlying anti-CTLA-4-mediated anti-tumor effects through destabilizing intratumor Tregs by CTLA-4 engagement-mediated TGF-{beta} signaling. This could lay a theoretical foundation for designing optimal immunotherapy based on anti-CTLA-4 antibody in cancer patients.

immunology↗

Distal conformational steering by N-terminal pyroglutamylation enables subtype-selective GPCR activation across Aplysia PRXamide and human Neuromedin U signaling

Post-translational modifications (PTMs) diversify neuropeptide function, yet how minimal modifications encode receptor specificity without direct contact remains a fundamental challenge in chemical biology. Pyroglutamylation (pQ), a prevalent N-terminal PTM in bioactive peptides, introduces a rigid cyclic constraint, yet its mechanistic role in receptor signaling is unclear. Here, using two newly identified endogenous Aplysia PRXamide receptors (ApPRXa R1 and ApPRXa-R2) as a model system, we find that the same ligand, MMG2-pDPb (pQPPLPRYamide), produces opposite functional outcomes: pQ suppresses ApPRXa-R1 activation while enhancing ApPRXa-R2 activation. In vitro and in silico analyses demonstrate that the N-terminal pQ/Q remains solvent-exposed and does not directly contact receptor residues. Instead, pQ reshapes the ligand conformational ensemble and redistributes interaction networks across shared receptor contact sites. Strikingly, this molecular logic extends to mammalian Neuromedin U (NmU) receptors, as canine NmU (pQFLFRPRNamide) similarly biases subtype preference of human NmU receptors. Both static and dynamic analyses further reveal that receptor pocket mechanics determine the direction of this modulation: a loose and permissive pocket better accommodates the rigid pQ-constrained ligand, whereas a more compact pocket favors the non-pyroglutamylated ligand. These findings define a "PTM distal steering" mechanism that bridges "lock-key" and "induced-fit" paradigms and establish a general principle by which a minimal, non-contacting modification encodes receptor preference through ligand conformational biasing and pocket-dependent permissiveness, providing a chemical framework for optimizing stable, conformation-biased neuropeptide analogs.

biochemistry↗

Rubber mapping reveals opportunities and current limitations of deforestation due-diligence

Commodity maps and the ability to monitor commodity-driven deforestation are essential for sustainability risk assessment and due diligence. Natural rubber (Hevea brasiliensis), used primarily in tyres, remains challenging to map because of its similarity to other tree cover. Integrating optical and radar satellite data, we produced a 10 m map of rubber distribution in Southeast Asia for around 2020 and assessed this map and similar products for deforestation due diligence. In continental Southeast Asia, estimated users accuracy was 0.95 and area-adjusted producers accuracy 0.78. Rubber-associated clearances of natural and semi-natural tree cover during 2011-2016 were estimated at 0.3-0.4 Mha, predominantly associated with industrial-scale plantations and concentrated in Cambodia. Historical clearances were less certain, with plausible bounds of 1.3-3.0 Mha since 1990. Evaluation of rubber and forest maps highlighted persistent limitations, particularly in insular Southeast Asia and smallholder systems. Accounting for these limitations is critical for fair and effective due diligence.

ecology↗

Nutrient flux governs osteogenic fate commitment through the SLC3A1-cystine Axis

Skeletal and mesenchymal cells have limited bone-forming potential due to their rarity, tendency for senescence and/or unstable osteogenic lineage commitment. We previously identified an osteopotent CXCR4 stem cell population with unclear mechanism for its differentiation potential. Here, we found that the cystine transporter SLC3A1 was selectively enriched in CXCR4+ stem cells, uncovering a role for amino acid transport in regulating osteogenic fate commitment. Enforced SLC3A1 expression reprogrammed mesenchymal cells toward a stable osteogenic state while suppressing adipogenic differentiation. Mechanistically, SLC3A1-mediated cystine flux established a glutathione-dependent metabolic program that preserved mitochondrial fitness and restrained stem cell senescence. SLC3A1 also stabilized IGF-1 through suppression of ZMYND8-mediated ubiquitination, uncovering ZMYND8 as a previously unrecognized E3 ligase regulating osteogenic commitment. Cystine supplementation phenocopied the effects of SLC3A1 activation, promoting osteogenic differentiation and skeletal regeneration without genetic manipulation. In vivo, cystine administration accelerated bone regeneration and attenuated ovariectomy-induced bone loss, while analyses of a human osteoporosis cohort, osteoporotic specimens, and single-cell transcriptomic datasets revealed coordinated suppression of the SLC3A1-cystine-IGF-1 pathway in osteoporotic mesenchymal cells. Taken together, these findings establish SLC3A1-mediated cystine transport as a programmable metabolic determinant of osteogenic fate commitment and identify cystine metabolism as a therapeutically targetable axis for skeletal regeneration and osteoporosis.

cell biology↗

A nutrient-derived dietary gradient links gut microbiome composition, network structure, and host physiology

Diet is an important determinant of gut microbiome composition and host physiology. However, dietary exposure is often represented using categorical groups that may not fully capture variation in nutrient intake or its associations with gut microbiome and host biomarkers. Here, we analyzed diet-microbiome-host physiology relationships in healthy adults with long-term adherence ([≥]2 years) to omnivore, vegetarian, or vegan diets. We integrated four-day weighed dietary records, blood biomarkers, and 16S rRNA gene sequencing to characterize dietary intake, host physiology, and gut microbiome composition. We derived nutrient intake gradients by dimensionality reduction of representative nutrients and identified the second nutrient intake gradient (NIG2) as a quantitative axis reflecting variation between animal- and plant-leaning nutrient profiles, broadly recapitulating categorical dietary groups. While NIG2 showed no association with microbiome within-sample diversity, it explained gut microbiome compositional variation that was not detected using categorical dietary groups. Mediation analyses identified nominal candidate microbiome-mediated diet-biomarker relationships involving thyroid-related, hematological, and vitamin-related biomarkers. Network analyses of NIG2-defined animal-leaning and plant-leaning subsets identified subset-specific microbial associations and differences in microbial community structure and potential interactions. Overall, this continuous nutrient-derived dietary gradient provides a quantitative exposure metric for characterizing diet-microbiome-host physiology relationships. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=97 SRC="FIGDIR/small/740531v1_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@104a825org.highwire.dtl.DTLVardef@bb2b33org.highwire.dtl.DTLVardef@114171org.highwire.dtl.DTLVardef@df9c38_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

Genetic Diversity and Antifungal Susceptibility among Ecological Niche Populations of Aspergillus flavus in Yaounde, Cameroon

Aspergillus flavus is a ubiquitous fungus commonly found in a variety of ecological niches including soil, crops, the air, and humans. In humans, it is the second leading cause of invasive aspergillosis (IA) and is linked to other illnesses through contamination of agricultural products with aflatoxins. As such, A. flavus threatens food safety, economic wellbeing, and human health, particularly in less developed regions and countries such as Cameroon. To mitigate these effects, farmers and clinicians rely on triazoles to reduce aflatoxin contamination and treat IA. However, a consequence of increasing triazole use is the emergence and spread of triazole resistance in both agriculture and clinics. To identify the prevalence of triazole resistance and the potential relationships among triazole resistant and susceptible strains, this study investigated antifungal susceptibility to both clinical and agricultural triazoles and analyzed genetic variation among various ecological niche populations of A. flavus in Cameroon. Strain genotypes were obtained through analysis of six polymorphic microsatellite markers. Our analyses revealed that 30.3% (17/56) of the strains were resistant to at least one of the four triazoles, with increased minimum inhibitory concentrations found among crop-isolated strains. A Permutational Multivariate Analysis of Variance suggested limited ecological niche-based clustering of genotypes, consistent with frequent gene flow and dispersal among ecological niches. A multilocus linkage disequilibrium analysis revealed evidence of non-random recombination in A. flavus. Overall, this study elucidates the interplay between ecological pressures, antifungal resistance, and genetic differentiation, and invites alternative methods to control aflatoxin contamination in foods without the use of agricultural fungicides.

microbiology↗

SemVac: A Semantic Vaccinology Paradigm Powered by LLMs for Antigen Discovery

Reverse vaccinology identifies vaccine antigens from pathogen genomes, yet existing methods rely mainly on sequence and structure and overlook the functional and immunological knowledge recorded in the published literature. We introduce semantic vaccinology, a paradigm in which large language models (LLMs) reason over literature-derived protein descriptions to predict protective antigens. Implemented as SemVac, the workflow retrieves publications linked to each protein through PaperBLAST, condenses the evidence into a structured semantic profile, and prompts an LLM to return an antigenicity probability. Benchmarked against a curated 246-protein bacterial benchmark and the specialized protein-language and geometric-deep-learning predictor PLGDL, the best of 14 general-purpose LLMs matched or exceeded the precision of PLGDL; the open-weight Kimi K2 0905 offered the strongest performance-cost balance. Predictions were robust to masking of vaccine keywords, reproducible across repeated inference, and generalized to a 1,200-protein cross-pathogen dataset. Surprisingly, explicit chain-of-thought reasoning increased recall but lowered precision in every model tested, revealing over-reasoning in biological scoring. Applied to the mpox virus proteome, SemVac recovered the established mpox antigen repertoire and prioritized uncharacterized candidates. Two of these, A30L and C19L, received independent experimental support in recent orthopoxvirus vaccine development, providing external validation. For one candidate, B20R, the model generated a coherent but false TNF-decoy narrative unsupported by curated annotations, demonstrating that LLM confabulation can be detected when reasoning traces are cross-checked against curated resources. Semantic vaccinology therefore establishes the literature as an explicit, auditable third modality alongside sequence and structure, while making its failure modes transparent and correctable.

immunology↗

Partial epithelial-to-mesenchymal transition mediates profound gap closure through growth and fluidization

Epithelial gap closure is essential for maintaining tissue integrity during development and wound healing. Previous studies have shown that closure of small gaps is driven by actomyosin purse-string contraction and traction forces generated at the gap edge. Here, we show that millimeter-scale circular gap closure in mouse epicardial (MEC1) monolayers is driven primarily by growth-mediated compressive stresses. Compared with MDCK monolayers, MEC1 cells close gaps more rapidly with reduced undulation near gap edge through coordinated tissue-wide extension-contraction. The collective closing dynamics can be modulated by partial epithelial-mesenchymal transition induction and Rho kinase inhibition. By integrating tissue and cell kinematic analyses, traction-force mapping, and a continuum framework that decomposes tissue strain rates into growth-, elastic-, and fluidity-related contributions, we reveal that growth-generated compression drives inward tissue flow, while elastic cell elongation and fluid-like tissue remodeling through cell-cell intercalation act synergistically to accommodate deformation and promote robust collective gap closure.

biophysics↗

Concurrent Stereotactic Body Radiation Therapy and KRAS Inhibition Synergistically Improve Pre-clinical Pancreatic Cancer Treatment

Pancreatic ductal adenocarcinoma (PDAC) is one of the most challenging cancers to treat due to the dismal survival rate, poor post-treatment outcome and profound resistance to a wide range of therapies. With mutant KRAS being a key driver, small molecule inhibitors targeting KRAS or pan-RAS (KRASi) have demonstrated exciting preclinical and early clinical anti-tumor efficacy, and the pan-RAS(ON) inhibitor daraxonrasib (RMC-6236) recently achieved Phase 3 clinically meaningful improvements in patient survival compared to chemotherapy. But resistance to RAS/KRAS inhibitor inevitably develops, which limits and compromises the treatment outcome. In this study, we investigated the combination of stereotactic body radiation therapy (SBRT) and KRAS inhibition (MRTX1133 and daraxonrasib) in the treatment of preclinical PDAC models. We found that this combination strategy synergistically suppresses PDAC cell growth in vitro and enhances tumor control while minimizing local recurrence in orthotopically implanted KPC (LSL-KrasG12D/+;Trp53R172H/+;Pdx1-Cre) murine PDAC tumors in vivo. As radiation therapy (RT) induces ferroptosis in multiple cancer types and mutant KRAS promotes various anti-ferroptotic mechanisms, we tested the role of ferroptosis in promoting tumor-control efficacy. Intriguingly, the addition of a ferroptosis inhibitor, liproxstatin-1, to the combination therapy significantly abrogated the in vivo synergism between SBRT and KRAS inhibition, suggesting that treatment-induced ferroptosis at least partially drives the synergistic efficacy of this combination strategy. Our study indicates that this SBRT-KRASi combination has the potential to overcome treatment resistance and improve outcomes in PDAC patients. These data directly support the design of a planned multi-center Phase 2 clinical trial with this combination strategy in locally advanced PDAC.

cancer biology↗

SALL2 constrains TEAD4 by maintaining repressive chromatin to restrict trophectoderm identity

Embryonic development is marked by the successive restriction of developmental potential and the specification of embryonic and extraembryonic lineages. Yet, how these lineage decisions are established, and how the epigenome is remodelled to promote and restrict cell fate transitions, remains poorly understood. Here, we demonstrate that SALL2 knockdown in primed human pluripotent stem cells (hPSCs) triggers a trophectoderm (TE)-like phenotype, characterized by palisade-like morphology and the up-regulation of TE-associated genes. Mechanistically, SALL2 physically interacts with the key TE driver TEAD4 and maintains bivalent, repressive chromatin (H3K4me3/H3K27me3) at TE-specific loci. Reduced SALL2 led to enhanced TEAD4 occupancy and disrupted H3K27me3 and increased active chromatin marks at TE genes. Importantly, depletion of TEAD4 abolished the TE-like phenotype induced by SALL2 knockdown, demonstrating that TEAD4 is required for the downstream effects of SALL2 loss. In support of this, blastoid-like aggregates can be generated from primed hPSCs with SALL2 knocked down. Together, our findings identify SALL2 as a key epigenetic barrier that restrains TE lineage commitment by limiting TEAD4-dependent activation of the trophoblast transcriptional program. Key findingsO_LISALL2 acts as a molecular barrier to trophectoderm differentiation. C_LIO_LISALL2 suppresses the trophectoderm by maintaining bivalent repressive chromatin at TEAD4-bound loci. C_LIO_LIBlastoid-like structures can be generated from primed-state media when SALL2 was knocked down. C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=91 SRC="FIGDIR/small/737659v1_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@42cafaorg.highwire.dtl.DTLVardef@11c040borg.highwire.dtl.DTLVardef@4d9ffborg.highwire.dtl.DTLVardef@42546a_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

Viral rewiring of DDR signaling activates a pro-survival network that drives chemotherapy resistance

Radiation and chemotherapy rely on an intact DNA damage response (DDR) to halt cell-cycle progression and eliminate damaged cells, yet many tumors evade these outcomes and develop resistance. Adenoviruses remodel host signaling networks in ways that mirror tumor evolution, providing a powerful system to dissect how DDR pathways are subverted. Here, we identify two scenarios in which the central DDR kinases ATM and ATR are reprogrammed from enforcing CHK1/CHK2-dependent checkpoint arrest to activating a NEMO-NF-{kappa}B survival pathway. This rewiring induces transcriptional programs associated with stress tolerance, anti-apoptotic signaling, and chemoresistance, and promotes the accumulation of cells with abnormal DNA content. These findings reveal a previously unrecognized mode of DDR plasticity that generates a pro-survival state reminiscent of early tumor evolution and suggest how ATM- and ATR-dependent pathways can be co-opted to promote therapeutic resistance.

molecular biology↗

CatESO: Differentiable Enzyme Sequence Optimization Guided by Substrate-Aware kcat Prediction

Enzymes drive biological chemistry and offer greener routes to chemicals, materials and medicines, yet their broader use as biocatalysts is often limited by insufficient catalytic turnover. Improving turnover is hard: measured rate constants are scarce and protein sequence space is vast. Deep-learning models now predict the turnover number, kcat, with growing accuracy, but they are typically applied after sequence generation to score or filter candidates, which separates the kinetic objective from the design itself. To bridge the gap between sequence generation and kinetic evaluation, we introduce CatESO, a differentiable sequence optimizer that enables direct, gradient-guided design of substrate-specific catalytic turnover. By backpropagating through a cross-modal kcat predictor under continuous sequence relaxation, CatESO co-optimizes predicted catalytic activity, evolutionary plausibility and structural integrity in one end-to-end framework, using ESM-2 and ESMFold to keep designs evolutionarily plausible and foldable. Across seven stringent out-of-distribution enzymes spanning EC classes 1-7, CatESO raised model-predicted kcat for the vast majority of designs, with a median predicted fold change of 1.52 while every variant retained a pLDDT above 70. Against RFdiffusion3-LigandMPNN pipeline and ZymCtrl, CatESO struck a better balance between predicted activity and structural confidence. By making substrate-conditioned kinetic objectives differentiable, CatESO carries differentiable protein design beyond structure- and binding-centred goals to enzyme catalytic function, giving a general route to function-oriented enzyme engineering.

biochemistry↗

The human language processing system straightens natural speech

Large language models trained on next-word prediction have impressive linguistic capabilities. This suggests that the goal of temporal prediction is essential to language processing, but how this goal impacts the structure of speech representations in the human brain remains unknown. Here, we test the hypothesis that prediction is facilitated by the temporal straightening of representational trajectories along the speech processing hierarchy. We developed a methodology for measuring the curvature of these trajectories using fMRI. Our method exploits a previously unknown connection between the timescale of single-unit responses and the curvature of population trajectories. We examined brain responses of subjects listening to natural speech. Response trajectories were most curved in lower-level auditory areas and progressively straightened along the cortical hierarchy. We presented the same speech stimuli and perturbed versions thereof to wavLM--a speech representation model that is well aligned with human brain responses--and found that hierarchical straightening effects are strongest for stimuli whose statistical structure resembles natural speech. Together, our results establish a direct connection between the goal of temporal prediction, the geometry of neural speech representations, and the cortical hierarchy of representational timescales.

neuroscience↗

Unveiling the Hidden Rules: Enhancing NMD Prediction for Protein-Truncating Variants

Nonsense-mediated decay (NMD) is a conserved RNA quality-control pathway that degrades transcripts containing premature termination codons. Because roughly a third of pathogenic variants in ClinVar can lead to truncated protein synthesis, predicting whether such transcripts undergo NMD is central to interpreting variant effects, yet the canonical 50-55 nucleotide rule explains only about half of observed outcome variability. Using paired whole-genome and RNA-sequencing from 10,306 individual samples in the Trans-Omics for Precision Medicine (TOPMed) program, we quantified NMD efficiency for 5,749 germline truncating variants via allele-specific expression and trained a gradient-boosting classifier, TrunCat, that distinguished NMD-sensitive from NMD-escape transcripts with [~]78% ROC-AUC (Receiver Operating Characteristic - Area Under the Curve). A reduced model using the ten features with the highest mean SHAP (SHapley Additive exPlanations) value as a measure of each features average contribution to predictions nearly matched this performance. Applied across large variant databases and a rare-disease cohort, the model produced NMD outcome predictions, with variants of uncertain significance showing higher predicted escape than pathogenic ones. This framework confirms the canonical rule, identifies non-canonical determinants, and offers a scalable resource for interpreting protein-truncating variants.

genomics↗

The CHIP-LMO7-BAG5 complex controls tau clearance and yields repurposed and newly designed therapeutic candidates for Alzheimer's disease

Through cross-species genetic screens, we identified LMO7 as a regulator of tau levels in vivo. LMO7 bridges the E3 ligase CHIP and its inhibitory cochaperone BAG5, suppressing CHIPs ligase activity and limiting tau ubiquitination and degradation. Adult LMO7 knockdown enhances CHIP activity, reduces total and phosphorylated tau, attenuates gliosis, and rescues memory deficits in tauopathy mice. Guided by AlphaFold-derived structural models and AI-based virtual screening, we developed a CHIP-derived competing peptide and identified FDA-approved drugs that disrupt the complex. Viral delivery of the peptide or oral administration of Telmisartan or MPA-2, an optimized Mycophenolic acid derivative, reduced pathogenic tau without toxicity. These findings establish CHIP-LMO7-BAG5 complex as a druggable node in tau homeostasis, with implications for tauopathies including Alzheimers disease, and STUB1-associated ataxias.

neuroscience↗

mTORC1 Directs TNF-Induced Life-or-Death Decisions via Complex I Destabilization

The transition from tumor necrosis factor (TNF)-induced plasma membrane-bound complex I to cytosolic death-inducing complex II switches cells from survival to death. However, the precise regulation of this fatal decision is incompletely understood. Here, we show that mTORC1 promotes this transition by destabilizing later-stage complex I without affecting its initial assembly. Inhibition of mTORC1 unleashes ATG9A and FIP200 activity, thereby promoting the accumulation of CHUK (IKK) in complex I. CHUK scaffolds the kinase-active IKK{beta} to stabilize complex I and prevent complex II formation. Activation of this ATG9A/FIP200-CHUK/IKK{beta} axis protects against TNF-induced fulminant hepatitis while compromises antibacterial defense against Staphylococcus aureus. This mTORC1-governed life-or-death transition provides therapeutic insight into TNF-related pathologies--including cancer, metabolic tissue injury, and microbial infections--where mTORC1 activity is frequently suppressed.

Cell Biology↗

Conversion of a Viral Glycan Shield into a Binding Anchor via Causal-Driven Antibody Optimization

Therapeutic antibodies are challenged by rapidly evolving pathogens that exploit glycosylation to shield epitopes. SARS-CoV-2 JN.1 exemplifies this, escaping antibodies through the N354-linked glycan. However, targeting glycosylated epitopes remains vacant, as scarce and heterogeneous glycan structures render existing approaches ineffective. Here, we introduce the Antibody Evolution Nexus with Causal-Driven Simulation (AENCS), integrating molecular simulation with causal inference. Applying AENCS to restore S309 efficacy against JN.1, we identified ACC01, exhibiting [~]24-fold improved neutralization. With limited prior knowledge of the N354 glycosylation site, ACC01 stabilized this glycan conformation, facilitating the determination of its cryo-EM structure. Causal dissection revealed how this glycan shield is functionally inverted into a binding anchor through multi-layered interactions. This mechanistic conversion, combined with the conservation of N354 glycosylation, enabled ACC01 to maintain potent activity against the latest variant NB.1.8.1. Collectively, AENCS demonstrates causal-driven antibody engineering can illuminate cryptic glycosylated epitopes, providing viable paradigms for exploring this vacant frontier.

bioengineering↗