bioRxiv ScienceSearch

SEARCH · bioRxiv Science

Results for “animal behavior and cognition”

Search indexed bioRxiv preprints in genomics, neuroscience, cell biology and bioinformatics. Read source abstracts and check manuscript versions; preprints are not peer reviewed.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

299 records · Page 6Linked to original sources

Immune-metabolic-redox ecosystems define spatially organized tumor states in head and neck squamous cell carcinoma.

Background: Spatial organization is increasingly recognized as a key determinant of tumor-immune interactions in head and neck squamous cell carcinoma (HNSCC). The GSE300147 Xenium spatial transcriptomic resource generated by McCord and colleagues established a framework for mapping spatially coordinated T-cell states in HNSCC. However, how tumor-enriched epithelial immune states relate to metabolic, redox, and stress-adaptive transcript programs remains incompletely defined. Methods: A secondary, data-driven reanalysis of GSE300147 was performed, focusing on 17 confirmed HNSCC Xenium sections after exclusion of a non-HNSCC ameloblastoma specimen. A total of 1,148,244 cells were analyzed, including 558,867 EpCAM+ tumor-enriched epithelial cells. Tumor-enriched epithelial cells were classified into Hot, Intermediate, and Cold states using a Composite Hotness framework integrating T-cell inflammatory signature score, checkpoint-associated signaling, CD274 expression, IFN/antigen-presentation signature score (IFN/AP), and tumor-immune proximity. Six metabolic ecosystem states, neighborhood profiling, spatial permutation testing, and an integrated Immune-Metabolic-Redox Ecosystem Score (IMRES) were then applied. Results: Immune activation was spatially heterogeneous across HNSCC sections. Immune-hot tumor-enriched epithelial regions showed not only inflammatory, checkpoint-associated, and antigen-presentation signature scores, but also coordinated metabolic, oxidative-redox, and stress-response transcript programs. IMRES, derived from available immune, metabolic, redox, and stress-response transcript components represented in the Xenium panel, increased progressively from Cold to Intermediate to Hot tumor-enriched epithelial states and was associated with NFE2L2, GDF15, HLA-DRA, CD274, KEAP1, and MDM2. Integrating IMRES with Composite Hotness identified a distinct Hot+IMREShigh ecosystem comprising 106,874 tumor-enriched epithelial cells. This state showed the strongest immune-active and stress-adaptive features and was positioned closer to immune populations than expected by random assignment. An alternative rank-based robustness analysis reproduced the IMRES-associated ecosystem axis and correlated with the original module-based score (Spearman r = 0.597). Conclusions: This secondary reanalysis extends the original spatial T-cell framework by defining a complementary tumor-centered immune-metabolic-redox ecosystem in HNSCC. IMRES provides a transcript-derived framework for identifying Hot+IMREShigh neighborhoods where immune activation, checkpoint signaling, metabolic remodeling, and stress adaptation converge, providing a hypothesis-generating framework for studying immune resistance and therapeutic vulnerability.

cancer biology

Estimating age and annual tooth growth rates in narwhals (Monodon monoceros) using computed tomography

The spiraling tooth of the narwhal (Monodon monoceros) has long intrigued scientists, but the growth rates of its "tusk" are poorly constrained due to the difficulty to age narwhal. To learn more about the population dynamics and life history of this exploited species, previous studies have used sectioned teeth to age narwhals and calibrate other ageing methods based on aspartic acid racemization, radiocarbon or trace element analysis. However, few such studies have been conducted due to the method's difficulty and the need to sacrifice the tooth. In this study, computed tomography (CT) was used on five teeth as a non-destructive means of estimating the age of narwhals, revealing different growth rates between erupted and embedded teeth during adolescence. Moreover, in combination with our reanalysis of all relevant literature, CT data clarify the annual growth rates of narwhal tusks, which peak before the age of 10 (~100 mm yr-1). This approach will be useful for investigating private and museum collections, and might also better constrain the use of trace element proxies in narwhal teeth and support sustainable harvest management.

zoology

Seed Microbiome Transfer Mitigates Intergenerational Dysbiosis, Modulates Plant Defenses and Suppresses Foliar Disease

Antibiotic-induced disruption of plant-associated microbiomes has the potential to alter host health beyond the directly exposed generation, yet whether the effects of dysbiosis are transmitted through the seed microbiome remains unknown. Here, we investigated the intergenerational impacts of streptomycin-induced dysbiosis in tomato (Solanum lycopersicum), demonstrated that seed microbiome transfer (SMT) restores progeny microbiome function and disease resistance, and characterized the underlying physiological and genetic mechanisms. Parental streptomycin exposure altered the composition of progeny rhizosphere bacterial communities, reduced expression of defense-associated genes, and increased susceptibility to Xanthomonas perforans. Suppression of immune gene expression was strongly associated with increased disease severity, indicating that parental dysbiosis impaired progeny plants ability to mount effective immune responses. Transfer of the seed microbiome from healthy plant donors partially restored rhizosphere community composition, reduced disease severity and recovered defense gene expression of three genes. Together, our findings demonstrated that antibiotic exposure microbiome disturbance generates intergenerational legacy effects that influence plant immunity and disease susceptibility and seed microbiome transfer can counteract this dysbiosis across generations.

plant biology

Structure and epitope mapping of the conformational anti tau antibody DC11

Conformational antibody DC11 was previously shown to discriminate between physiological full length tau proteins and misfolded truncated tau proteins. It was also shown to catalyze in vitro tau aggregation, suggesting a connection with the pre-aggregation conformation of tau proteins. We have crystallized the Fab fragment of the DC11 antibody and characterized its binding with truncated tau proteins using ELISA, NMR and crosslinking mass spectrometry. The presumed model of the complex of DC11 antibody and truncated tau protein was obtained by docking tau321-391 conformations from coarse grained MD simulation into the antibody paratope.

biophysics

Structural characterization the LlaI anti-phage defense system reveals insights into the evolution of nucleotide specificity and the organization of DNA binding in McrBC restriction complexes

Canonical McrBC enzymes are nucleotide-powered, motor-driven endonucleases that bind and cleave modified bacteriophage DNA. Non-canonical McrBC homologs like LlaI and BsuMI are distinguished by a unique three-gene organization and the ability to target DNA site-specifically. Here, we report the atomic-resolution crystal structures of the DNA-binding module LlaI.R1 and AAA+ motor LlaI.R2 from the Lactococcus lactis LlaI anti-phage defense system. The crystallized LlaI.R2 hexamer traps two distinct active site conformations that correlate to different states of the nucleotide hydrolysis cycle and reveal that the organization of the critical catalytic machinery present in canonical McrB homologs is also conserved in non-canonical R2 proteins. Although canonical McrB homologs are strictly GTP-specific, we find that the R2 proteins from LlaI and BsuMI do not discriminate between different nucleotides, even when in complex with their respective R1 partners. Using mutagenesis, we define surfaces on the LlaI.R1 structure that are critical for DNA-binding and interaction with LlaI.R2. These observations support computational modelling of the assembled LlaI restriction system bound to DNA. Together, our data provide new insights into the evolution of nucleotide specificity in McrBC restriction complexes and the molecular mechanisms governing McrBC-catalyzed DNA translocation and cleavage.

biochemistry

Profiling and modulating astrocyte borders at injected biomaterials in mice

Astrocyte border formation is a conserved neuroprotective response to neural tissue disruption, yet astrocyte border states at implanted biomaterials remain less well characterized than injury responses. Here, we developed the Astrocyte Border Characterization (ABC) Tool, which leverages a shear-thinning, injectable biomaterial to locally deliver astrocyte-specific RiboTag AAVs and small molecule regulators in the mouse striatum, enabling molecular profiling and phenotypic modulation of astrocyte border (AB) cells. Spatially precise delivery of AAV using the ABC Tool yielded enhanced specificity and robust RiboTag expression in AB cells from 7-70 days post injection. Temporal transcriptomic profiling of AB cells revealed predominantly acute, transient changes in genes governing dedifferentiation, proliferation, metabolic reprogramming, and inflammation regulation. Persistent changes accounted for only 14% of regulated genes but involved critical gain of functions in immune regulation and host defense that mirrored astrocyte border responses at chronic CNS injuries. Local delivery of indiscriminate or astrocyte-selective ablation molecules delayed, rather than prevented, border formation, ultimately yielding thicker astrocytes borders with increased inflammation and fibrosis at the biomaterial-tissue interface. Conversely, local delivery of {beta}-hydroxybutyrate (BHB) from the ABC Tool altered key aspects of the transcriptional reprogramming to attenuate chronic astrocyte reactivity and prevent biomaterial contraction without exacerbating inflammation or fibrosis. Our findings establish the ABC Tool as a bioassay for studying and manipulating astrocyte borders at implanted biomaterials and identify focal metabolic regulation as a strategy to modulate AB cell phenotypes and enhance the CNS biocompatibility of biomaterials.

neuroscience

Data-driven spectroscopic dictionaries and detector-calibrated inference for photon-limited Raman hyperspectral imaging of living cells

Label-free Raman imaging of living cells is photon limited: at exposures compatible with cellular dynamics, single-pixel spectra carry about one count per channel on a dominant smooth background. We present an unmixing framework in which the decoder of a physics-constrained autoencoder is restricted to a data-driven spectroscopic dictionary: band centers,widths, and pseudo-Voigt shapes are measured from the dataset and fixed, and the network learns only nonnegative band amplitudes, a smooth B-spline background, and a per-pixel gain.First, on slit-scanning images of HeLa cells (532 nm) the dictionary yields spike-free component spectra that read as band tables, including a resonance-enhanced cytochrome-c-associated component matching literature spectra, and the most stable decomposition against the component number. Second, the dictionary and initialization calibrated at 1 s exposure perline transfer to 100 ms per line (12 s sweeps): cytochrome-c spectral identity survives a single sweep (correlation 0.92) while its map remains photon limited; the dictionary provides spectral physicality, and the transferred initialization prevents a structural collapse that global map correlations miss; in a measurement-derived phantom the dictionary estimator holds thecytochrome-c spectrum to 17-19{degrees} spectral angle at 100 ms, where classical factorizations and free decoders lose it (55-64{degrees}). Estimation on the count-equivalent detector output uses a calibrated shifted-Poisson quasi-likelihood. Third, evaluation must be time matched:correlation against a separately acquired reference saturates through slow specimen drift and acquisition mismatch rather than photon noise, and the self-consistency of learned denoisers is inflated by shared bias; time-matched self-consistency and independent cross-checks areproposed.

cell biology

Zebrafish larval nitrogen excretion is flexible and resilient to loss of rhesus glycoproteins

Nitrogenous waste excretion is essential for all developmental stages of fish. Embryonic fish excrete urea, transitioning to cutaneous and later branchial ammonia excretion. In zebrafish, ammonia excretion involves rhesus glycoproteins Rhbg and Rhcgb in keratinocytes and ionocytes, but the developmental moment they appear in the gill remains unclear. Potential redundancy between Rhbg and Rhcgb in ammonia excretion is also not fully investigated, nor is the difference in response to low pH. We hypothesized that rhesus glycoproteins are partially redundant, and that they differ in their response to low pH as ammonia excretion enables ionocytes to exchange Na+ and H+ (Rh-NHE-metabolon). We predicted that a loss of rhbg or rhcgb induces compensatory responses. We characterized the transition from urea to branchial ammonia excretion from 0 to 8 days-post fertilization (dpf) and the response to pH 5.0 on the expression and localization of rhesus glycoproteins in control zebrafish and rhbg or rhcgb-crispants. Effects of high external ammonia (HEA, 500 M NH4Cl) and 10 mM HEPES-buffering were further characterized in rhcgb-crispants. Rhag and Rhbg appeared in the gill at 5 dpf, while Rhcgb appeared at 6 dpf. A loss of rhbg or rhcgb did not impact baseline N-excretion, illustrating that zebrafish can maintain ammonia excretion without the full complement of rhesus glycoproteins. We observed no compensatory increase in rhesus glycoproteins, but expression of the transporter hippocampus-abundant transcript 1b increased. HEA-exposed rhcgb-crispants switched to urea as primary nitrogen waste. Together, these findings underline the plasticity of the larval in dealing with nitrogenous waste.

physiology

PhageTAILor leverages machine learning for phage tail-like elements detection and classification in plant-associated bacteria

Phage tail-like elements (PTEs) -- tailocins, bacterial type VI secretion systems (T6SS), and extracellular contractile injection systems (eCIS) -- are contractile nanomachines that bacteria use to kill their neighbors and compete within their micro-ecosystems. PTEs help shape microbial community composition. Most PTE detection tools only detect a single PTE class. Moreover, most tailocin detection methods are largely restricted to Pseudomonas, leaving a key part of tailocin diversity uncharacterized. In this work, we present PhageTAILor (https://github.com/hjcho-bio/PhageTAILor), an integrative and fully automated pipeline that detects and classifies prophages and 3 PTE classes from bacterial genomes. PhageTAILor combines a 6-detector homology-based candidate search (geNomad, tail-gene, PHROGs-tail, SecReT6, eCIStem, and a divergence-tolerant tail-HMM detector) with a LightGBM classifier comprising 1 multiclass and 3 binary heads, trained on 6,501 bacterial genomes carrying 13,082 prophages and PTEs. A phylogeny-free feature matrix used in our model keeps predictions reproducible between model construction and user inference. PhageTAILor performs strongly at the genome level and generalizes beyond its Pseudomonas-rich training set. On a 76-strain cross-clade benchmark, PhageTAILor detected tailocins at F1 = 0.955. Furthermore, it identified 12 of 13 experimentally validated tailocins spanning five genera versus 2 of 13 for a Pseudomonas-restricted tool TattleTail. PhageTAILor also demonstrated sensitivity equivalent to viral detection tool geNomad while avoiding its higher false-positive rate. Applied to 7,925 plant- and soil-associated bacterial isolates, PhageTAILor showed that prophages in the phyllosphere and tailocins in plant-associated bacteria, whereas eCIS are enriched in soil. PhageTAILor is distributed as an open-source, modular pipeline with a command-line interface.

microbiology

Ex vivo glioblastoma migration phenotypes define clinical recurrence and tumor heterogeneity

Glioblastoma's pronounced migratory capacity underlies its diffuse invasion, presenting a formidable barrier to successful treatment. Ex vivo characterization of glioblastoma cells isolated from freshly resected clinical samples under physiologically relevant conditions revealed two distinct migratory phenotypes, Fast Migrating (FM) and Slow Migrating (SM). These phenotypes reflect distinct mechanosensitivity profiles and are associated with pharmacological responses that support the motor clutch model of cell migration. Analysis of genes associated with these phenotypes revealed a transcriptomic signature that closely associated with in vitro cell migration, histological invasion in patient specimens, and clinical survival. Single-nucleus RNA sequencing revealed that FM and SM cells coexist within a single glioblastoma, with FM cells enriched at the periphery and SM cells localized to the tumor core. Collectively, our study demonstrates the utility of ex vivo glioblastoma characterization, allowing decoding of tumor heterogeneity and clinical prognostication as well as providing a framework for deconvoluting the complex cancer phenotype.

cancer biology

VDAC1 regulates stress-associated matrix localization of DJ-1 to support mitochondrial homeostasis and neuronal survival

DJ-1 is a redox-sensitive protein implicated in early-onset Parkinson's disease, and its mitochondrial localization protects against oxidative stress, but the mechanisms regulating its submitochondrial targeting and functional impact on mitochondrial integrity remain poorly understood. We identify voltage-dependent anion channel 1 (VDAC1) as a regulator of the submitochondrial distribution of DJ-1 during stress. Endogenous DJ-1 interacted with VDAC1, and loss of VDAC1 reduced stress-induced DJ-1 accumulation within the mitochondrial matrix. VDAC1-deficient neurons exhibited mitochondrial fragmentation, impaired oxidative phosphorylation, reduced ATP levels, altered reactive oxygen species (ROS) responses, and increased sensitivity to MPP+;. Matrix-targeted, but not outer-membrane-targeted, DJ-1 rescued basal, ATP-linked, and maximal respiration, improved mitochondrial morphology, and enhanced neuronal survival. ATP synthase inhibition also rapidly increased mitochondrial DJ-1, suggesting bioenergetic stress promotes its mitochondrial accumulation. Our findings identify compartment-specific localization as a key determinant of DJ-1 function and establish VDAC1-dependent matrix targeting as a critical mechanism supporting mitochondrial integrity during stress.

neuroscience

Sequential Molecular Interactions Shape Aβ42 Aggregation, Propagation, and Toxicity

Protein aggregation is a context-dependent process in which the molecular environment can influence the properties of the resulting assemblies. In biological systems, these interactions can occur sequentially, as aggregates formed in one cellular or tissue context may encounter different molecular partners and act as seeds in subsequent aggregation events. Here, we used sequential seeding as a controlled experimental model of this temporal and contextual complexity to investigate how prion-like sequences from the gut microbiome modulate amyloid-{beta} aggregation across successive aggregation cycles. Combining kinetic, biophysical, conformational, and toxicity analyses, we show that early interactions with exogenous peptides modify the properties of first-generation A{beta}40- and A{beta}42-derived seeds, resulting in propagated A{beta}42 assemblies with distinct molecular and functional properties. These findings support an Interaction History model in which exogenous sequences bias the emergence of aggregate populations whose properties and subsequent propagation depend on the molecular contexts experienced during earlier aggregation events. Overall, our results present A{beta} aggregation as a history-dependent process and suggest that single-step assays may fail to capture aggregate diversity that emerges across successive aggregation cycles.

biochemistry

DIFFERENTIAL PHOTOSYNTHETIC RESPONSES TO GLUFOSINATE AMMONIUM IN TWO GRASS WEEDS: Lolium multiflorum AND Echinochloa crus-galli.

Background: Weed control is one of the main challenges in agriculture today, particularly due to the increasing occurrence of herbicide-resistant populations. Among the most problematic species are Lolium multiflorum (L.) and Echinochloa crus-galli (L.) Beauv., for which glyphosate-resistant populations have been reported. In this context, glufosinate ammonium has emerged as an alternative for their control; however, its efficacy may vary depending on species and photosynthetic metabolism. Objective: The objective of this study was to evaluate the differential sensitivity of ryegrass (C3) and barnyardgrass (C4) to ammonium glufosinate by analyzing physiological responses associated with leaf senescence and photosystem II activity. Methods: Visual injury, chlorophyll fluorescence, and ammonium accumulation were assessed. Results: Results revealed a differential response between species. Barnyardgrass exhibited earlier symptom onset and a greater reduction in the quantum yield of photosystem II ({Phi}PSII), whereas ryegrass showed a slower senescence process. These differences indicate a higher sensitivity of barnyardgrass to glufosinate ammonium, possibly associated with its C4 photosynthetic metabolism. Conclusions: It is concluded that the effectiveness of glufosinate ammonium depends on the type of photosynthetic metabolism and on the ability of each species to cope with herbicide-induced oxidative stress. This information contributes to optimizing glufosinate ammonium use and to the development of management strategies aimed at delaying the evolution of herbicide resistance.

plant biology

Sensory neuron dysfunction and hyperexcitability in dorsal root ganglia at disease onset in the SOD1G93A mouse model of ALS.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder traditionally characterized by motor neuron degeneration, but emerging evidence indicates sensory system involvement. Despite reports of sensory abnormalities in some patients, the molecular and functional alterations in dorsal root ganglion (DRG) neurons remain insufficiently characterized. We investigated DRG pathology at disease onset in 12-week-old SOD1G93A mice using an integrated transcriptomic, morphological, and electrophysiological approach. RNA sequencing of lumbar DRG identified 35 differentially expressed genes, predominantly upregulated, enriched in oxidative stress-related and phagosome pathways. Comparative analysis with motor neuron transcriptomes revealed distinct gene expression profiles, indicating sensory neuron-specific molecular responses. Immunohistochemistry demonstrated reduced soma diameter in both A- and C-fiber DRG neurons. Nav channel colocalization increased for Nav1.7 in A fibers and Nav1.8 in both fiber types, whereas Nav1.6 was unchanged. Whole-cell patch-clamp recordings showed depolarized resting membrane potential, increased spike amplitude, and enhanced repetitive firing in A-fiber neurons, consistent with hyperexcitability, while C fibers showed no significant functional changes. These findings demonstrate early molecular, structural, and functional alterations in primary sensory neurons in ALS, supporting pathology beyond motor neurons and identifying sensory neuron excitability as a potential therapeutic target.

neuroscience

Cas12a cleavage and trimming kinetics reveal mismatches as a tool to steer editing

Gene knockouts by CRISPR-Cas nucleases rely on targeted DNA cleavage and error-prone DNA repair: end-joining pathways can introduce insertions and deletions that assist in disrupting the coding sequence. However, only a fraction of edits achieves this, and an unfavorable array of repair outcomes typically requires switching to another editing technology. Key factors that influence repair are the types and lengths of DNA ends following cleavage. Here, we investigated Cas12a's ability to produce different ends and if they can be used to redistribute editing outcomes. We determined the sites and rates of target cleavage by Cas12a in vitro by combining kinetic modeling with nucleotide-resolution assays. For the first time, we show that trimming - repeated cleavage of an already cut target - occurs about 4x faster than initial cleavage; it also presents alternative DNA end structures for cellular repair. We next introduced specific mismatches to the gRNA. Cas12a maintained fast target cleavage, but changed where the target was cleaved and how quickly it was trimmed, compared to matched gRNA. We exploited the differences in cleavage dynamics between matched and mismatched gRNAs to develop reprogrammed gRNAs, i.e. rpgRNAs. Intentionally-mismatched rpgRNAs retained the high editing efficiency observed with traditional gRNAs. However, they redirected editing between in-frame and out-of-frame outcomes to enhance gene knockout success across genes. Reprogrammed gRNAs offer an efficient way to steer editing toward such preferred outcomes, while retaining the simplicity of gene editing with CRISPR-Cas nucleases.

biochemistry

POU2AF2/OCA-T1 coactivates POU2F2 and defines a lineage-specific dependency in diffuse large B-cell lymphoma

Lineage-restricted transcriptional programs establish cell identity and can create selective dependencies in cancer. Here, we identify POU2AF2, encoding the transcriptional co-activator OCA-T1, as a critical lineage-specific dependency in a subset of diffuse large B-cell lymphoma (DLBCL). Pan-cancer dependency analyses and patient cohorts reveal elevated POU2AF2 expression in genetically aggressive DLBCL, where its depletion markedly suppresses tumor growth in vitro and in vivo. Mechanistically, POU2AF2 cooperates with the B-cell lineage-defining transcription factor POU2F2 (OCT2) to activate lymphocyte activation gene programs through direct chromatin engagement, thereby sustaining malignant transcriptional networks. We further identified a key epigenetic regulatory axis composed of the lineage-specific transcription factor TCF3 and the histone methyltransferase SET1A-COMPASS that drives POU2AF2 expression downstream of B-cell receptor signaling. Single-cell transcriptomic analysis reveals that POU2AF2 marks and sustains an innate-like B1 B-cell population in vivo, a candidate cell of origin for lymphoma. Together, these findings define a lineage-restricted POU2AF2/POU2F2 transcriptional module, controlled by a TCF3/SET1A epigenetic network, that sustains both innate-like B-cell identity and malignant fitness in DLBCL. Our study uncovers a previously unrecognized lineage-specific transcriptional dependency and highlights POU2AF2 and its associated regulatory circuitry as potential therapeutic targets in aggressive B-cell malignancies.

cell biology

Azithromycin Derivatives to Mitigate Off-Target Inhibition of Autophagy and Retain Beneficial Host Directed Effects

Azithromycin (AZM) is central for the treatment of chronic respiratory diseases (CRD) but has divergent off-target effects. We synthesised AZM Derivatives 1 and 2 (D1/D2) that were predicted to permit autophagy and preserve AZM's anti-inflammatory effect. The 16HBE14o- airway epithelial cell model was exposed to AZM, D1 and D2 for 16 h and assessed for autophagy flux via LC3B-II:p62/SQSTM1 abundance (Western blot). Necrosis was quantified via lactate dehydrogenase release. Inflammation (IL-6 secretion) was assessed in the THP-1 macrophage model exposed to 10 ng/mL lipopolysaccharide vs co-treatment with AZM and the derivatives for 18 h. AZM-derivative antibacterial activity (vs AZM) was determined via the minimum inhibition concentration (MIC) method using methicillin sensitive Staphylococcus aureus (MSSA). Autophagy (LC3B-II and p62/SQSTM1 abundance) was not altered by the two derivatives and was indistinguishable from the control exposure (P> 0.05 for D1 and D2, each 10 and 50 ug/mL, vs control). D2 elicited a significant decrease in LPS-induced IL-6 secretion vs the LPS-only exposure (58.22 pg/ml, n=3, 95% +/- CI [6.521-109.9]). Importantly, D2 caused a similar reduction in LPS-induced IL-6 secretion, as observed for AZM (-10.30 pg/mL, n=3, 95% CI [-62.00 to 41.39]). The MIC of AZM for MSSA growth was 0.5 ug/ml, where as D1 and D2 were 1.0 and 8.0 ug/mL, respectively (P<0.05). We show for the first time that AZM can be redesigned to mitigate its potent arrest of autophagy while preserving its anti-inflammatory activity, to counter the generation of further AZM resistant strains.

cell biology

PGM3 inhibition rewires RUVBL2-dependent DNA repair and induces a BRCAness-like state in pancreatic cancer cells

Pancreatic ductal adenocarcinoma (PDAC) exhibits profound metabolic rewiring and strong resistance to DNA-damaging therapies, yet how metabolic pathways regulate genome maintenance remains poorly understood. The hexosamine biosynthetic pathway (HBP) integrates nutrient availability with protein glycosylation through production of UDP-GlcNAc, but its role in DNA damage response (DDR) regulation is unclear. Here we show that inhibition of the HBP enzyme phosphoglucomutase-3 (PGM3) reduces DNA repair capacity in pancreatic cancer cells. Transcriptomic and functional analyses reveal that the selective PGM3 inhibitor FR054 amplifies gemcitabine-induced replication stress, disrupts ATR-CHK1 and ATM-CHK2 checkpoint signaling, and selectively impairs homologous recombination. Glycoproteomic profiling identifies the AAA+ ATPase RUVBL2 as a key metabolic-DDR node. Gemcitabine increases RUVBL2 O-GlcNAcylation, with Thr81 identified as a modified residue within the Walker A nucleotide-binding motif. Structural modelling predicts that Thr81 O-GlcNAcylation stabilizes the RUVBL1-RUVBL2 complex without compromising ATP-Mg engagement. PGM3 inhibition and Thr81 mutation similarly reduced ATR and ATM abundance and promoted persistent DNA damage, supporting a role for RUVBL2 Thr81 O-GlcNAcylation in sustaining checkpoint signalling and genome stability. Consequently, PGM3 inhibition induces a BRCAness-like state that sensitizes pancreatic cancer cells to PARP inhibition, both in vitro and in vivo, as well as to ionizing radiation. These findings reveal a nutrient-sensitive mechanism linking protein glycosylation to genome maintenance and identify HBP-dependent DNA repair as a potentially actionable vulnerability in pancreatic cancer.

cancer biology