Biology subjects

Kim, A.

Publications and source records attributed to Kim, A..

At least 19 recordsLinked to original sources

bioRxiv2026

Sunflower sea star (Pycnopodia helianthoides) environmental DNA (eDNA) shedding and decay: Influence of sunlight and comparison to other marine organisms

Conservation practitioners increasingly turn to environmental DNA (eDNA) for biomonitoring, yet interpreting DNA-based data requires attention to organismal shedding and decay dynamics. Here, we characterize shedding rates and decay rate constants of eDNA from Pycnopodia helianthoides, a critically endangered and ecologically important sea star in the Northeast Pacific Ocean. Shedding rates were quantified via a mesocosm experiment utilizing twelve stars of varying sizes, and decay rate constants were calculated for naturally shed P. helianthoides eDNA under natural sunlit and dark conditions for 96 hours. We additionally completed a systematic search and review of marine organism shedding rates and decay rate constants. P. helianthoides decay rate constants (k) were not different under sunlit and dark conditions (average k=0.0257 hr-1) and among the lowest third reported for marine organisms. Similarly, biomass-normalized shedding rates (between 896 and 19,800 copies/hr/g) and shedding rates per individual (between 22,000 and 548,000 copies/hr/individual) were among the lowest recorded across marine organisms. Shedding rates were influenced, in part, by organism stress levels. This work aids interpretation of measured eDNA concentrations in marine environments and serves as a roadmap for integrating shedding and decay studies into eDNA assay design.

ecology↗

bioRxiv2026

Preferential innervation of endometriosis by hyperexcitable Ret/GFRα1+ nociceptors associates with target GDNF and clinical pain

Endometriosis is a prevalent condition characterized by chronic pelvic pain that is frequently refractory to treatment. While the mechanisms underlying this pain remain poorly defined, clinical evidence often indicates that lesion innervation, but not disease stage (e.g. number and depth of lesions), correlate with pelvic pain severity. However, characterization of lesion-innervating neurons is incomplete, revealing an opportunity to identify novel, disease-modifying therapeutics. Here, we coupled functional analyses of lesion-innervating neurons in a mouse model with concurrent identification and characterization of lesion-innervating neurons from pain-phenotyped endometriosis patients. Following the confirmation of abdominal-directed pain-like behaviors in the mouse model, electrophysiological analysis revealed that lesion-innervating dorsal root ganglion (DRG) neurons are hyperexcitable compared to matched controls. These neurons are predominantly small-diameter and bind Isolectin B4, an established marker of the GDNF Family Ligand receptor, Ret. GDNF is concentrated within the stromal layer of both mouse and human lesions, adjacent to axons expressing the GDNF co-receptor, GFR1. Critically, clinical pain correlates with lesion GDNF level, axonal density, and neuronal GFR1 levels. These data provide evidence that endometrial lesions may recruit the Ret-positive subpopulation of nociceptors where they become sensitized and increase patient pain.

neuroscience↗

bioRxiv2026

A microbial metabolite reduces alcohol-induced inflammation via dual modulation of NF-κB and Interferon pathway

Background and aimsAlcohol-associated hepatitis (AH) is characterized by excessive inflammation and blunted antiviral interferon (IFN) responses. We hypothesized that specific gut microbiome-derived metabolites could selectively enhance interferon signaling while limiting NF-{kappa}B mediated inflammation, thereby restoring immune balance in AH. Our goal is to identify microbiome-derived metabolites that differentially regulate the NF-{kappa}B and IFN signaling pathways. Methods and resultsWe used human monocytic THP1-Dual cells, which secrete reporters for NF-{kappa}B and IFN signaling, to model innate immune responses and screened a library of 152 gut microbiome-derived metabolites. From the metabolite screen, 4-hydroxyphenylacetic acid (4-HPAA) emerged as a unique immunomodulator: in LPS-challenged cells, 4-HPAA selectively increased IFN signaling with minimal NF-{kappa}B activation. 4-HPAA was evaluated in vivo using a NIAAA-model, with 4-HPAA supplementation (0.4mg/ml) added to the diet. In the NIAAA-model, dietary 4-HPAA did not induce liver injury and was associated with enhanced interferon-stimulated gene expression. Simultaneously, 4-HPAA reduced pro-inflammatory markers such as Il1{beta}, Ly6g and F4/80 compared to the group exposed to ethanol alone. Metabolomic profiling of mouse cecal contents revealed 4-HPAA supplementation counteracted ethanols metabolic effects, selectively reducing triglyceride-associated lipids that had accumulated with ethanol feeding. Conclusions4-HPAA enhances interferon signaling and antiviral gene induction while dampening NF-{kappa}B-driven inflammation in the presence of LPS, both in vitro and in vivo. In an acute-on-chronic alcohol injury model, 4-HPAA attenuated hepatic inflammation, reduced immune cell recruitment, and activated antioxidant defenses, reflecting a shift toward a more hepatoprotective effect. 4-HPAA treatment was associated with reduced pro-inflammatory markers and modest attenuation of ethanol-induced liver injury. Additionally, 4-HPAA reversed ethanol-induced lipid-dysregulation, particularly triglyceride accumulation, highlighting its metabolic benefit in alcohol-fed mice. In conclusion, 4-HPAA rebalances immune and metabolic pathways by enhancing IFN signaling, suppressing NF-{kappa}B inflammation, and reversing alcohol-induced hepatic injury and lipid accumulation.

immunology↗

bioRxiv2026

The SLC15A4-LAMTOR1 interaction licenses endolysosomal TLR-mediated mTOR signaling and inflammatory cytokine production

Endolysosomal Toll-like receptors (TLRs) 7-9 are critical mediators of antimicrobial immunity, but their dysregulation drives pathogenic inflammation in autoimmune diseases such as systemic lupus erythematosus (SLE). The endolysosomal solute carrier SLC15A4 is essential for TLR7-9-mediated cytokine production and is strongly linked to SLE susceptibility, yet our understanding of the precise mechanisms by which it coordinates innate immune signaling remains incomplete. Here, we identify a direct interaction between SLC15A4 and LAMTOR1, a core scaffold subunit of the lysosomal Ragulator complex, and show that is required for coupling endolysosomal TLR activation to mTORC1 and downstream inflammatory responses. Structural modeling and site-directed mutagenesis suggest that the 1 helix of LAMTOR1 engages the substrate-binding pocket of SLC15A4, and disruption of this interface broadly suppresses TLR7-9-mediated cytokine production. Notably, this interaction regulates mTOR activation, IRF5/7 signaling, and downstream transcriptional responses through stimulus-dependent mechanisms. These findings define a previously uncharacterized SLC15A4-LAMTOR1 signaling interface that coordinates endolysosomal TLR-mTOR coupling and shapes downstream cytokine output. Significance StatementDysregulated activation of endolysosomal Toll-like receptors (TLRs) 7-9 drives pathogenic inflammatory cytokine responses that underlie autoimmune diseases such as systemic lupus erythematosus. Despite the established role of the endolysosomal transporter SLC15A4 in this process, how it coordinates downstream immune signaling has remained incompletely understood. We show that SLC15A4 directly interacts with LAMTOR1, a core component of the lysosomal Ragulator complex, and that this interaction is required to activate mTOR and engage IRF5/7-dependent inflammatory programs downstream of TLR7-9. Disrupting this interface suppresses type I interferon and cytokine production, identifying the SLC15A4-LAMTOR1 interaction as a central node in endolysosomal innate immune signaling and validating it as a compelling target for therapeutic intervention in interferon-driven autoimmune disease.

immunology↗

bioRxiv2026

Dynamic organizational strategies of multidomain glycosyltransferases revealed by high-speed AFM and solution biophysics

Glycosyltransferases often contain multiple structural modules that contribute to substrate recognition, catalytic coordination, and higher-order molecular organization. However, how multidomain glycosyltransferases dynamically organize their catalytic domains in solution remains poorly understood. Here, we investigated the assembly states and conformational dynamics of POMGNT2, LARGE1, K4CP, and L137 using high-speed atomic force microscopy (HS-AFM) integrated with complementary solution biophysical analyses. POMGNT2 formed a stable dimeric architecture with limited large-scale conformational fluctuation, consistent with its role in site-selective substrate recognition. In contrast, LARGE1 and K4CP exhibited concentration-dependent and heterogeneous assembly behavior. K4CP displayed pronounced open-closed interdomain motion and substrate-dependent conformational compaction, indicating dynamic catalytic-domain reorganization during glycan elongation. By comparison, the mimivirus glycosyltransferase candidate L137 predominantly behaved as a monomeric species under the tested conditions. These findings demonstrate that multidomain glycosyltransferases employ diverse dynamic organizational strategies ranging from rigid recognition architectures to highly flexible and reversible catalytic assemblies. Our results further suggest that glycosyltransferase function is governed not only by catalytic-domain structure, but also by dynamic conformational coordination adapted to distinct catalytic demands.

biophysics↗

bioRxiv2026

Molecular Star Gazing: Development and Validation of an Environmental DNA Assay for the Imperiled Sunflower Sea Star (Pycnopodia helianthoides)

The sunflower sea star (Pycnopodia helianthoides) suffered a catastrophic population decline across its range from 2013 to 2017 due to the devastating Vibrio pectenicida FHCF-3 driven sea star wasting disease (SSWD) pandemic with minimal signs of population recovery. The functional extinction of this apex predator across substantial parts of its range has created a need to identify and track the remaining intact populations. Environmental DNA (eDNA) approaches provide a simple, cost-effective, and non-destructive method for monitoring occurrences, and in some cases abundances, of marine species, consistently outperforming visual occurrence monitoring efforts in sensitivity, speed, and cost. Here, we designed, developed, and validated a P. helianthoides-specific eDNA assay to identify refugia, using both quantitative and digital droplet PCR approaches. We first generated the most comprehensive sea star mitochondrial genome reference database to date (n=93 taxa, n= 15 novel). We then used unikseq and Geneious bioinformatics software to identify the unique nad5 gene region and design a highly specific hydrolysis probe-based PCR assay. We validated the performance of this assay through laboratory, mesocosm, and field testing, demonstrating a highly specific and sensitive assay. In a field application of the new assay across regions in British Columbia, Canada, we found a positive correlation between P. helianthoides eDNA concentrations and biomass density, especially when appropriately accounting for spatiotemporal integration scales (R2=0.67). The eDNA assay provides a rapid and scalable tool for monitoring the sunflower sea star which has been proposed for listing as threatened under the U.S. Endangered Species Act of 1973. Molecular tools like the one presented here enhance management and recovery efforts not only by identification and monitoring of remnant wild populations, but also by helping to assess population level response and recovery following reintroduction efforts.

molecular biology↗

bioRxiv2026

Genetic suppression of myeloid receptor Clec7a attenuates microglia neuroinflammation and promotes microglial phagocytosis to delay disease progression in ALS models

Microglial activation has been closely associated with accelerated ALS disease progression. However, specific microglial pathways that regulate microglial activation and ALS disease progression remain limitedly understood. Here, we determined the role of Clec7a (or Dectin-1), a core signature gene of disease-associated microglia (DAM) in ALS, in regulating microglial activation and ALS disease progression. Our spinal cord scRNA-Seq results found that Clec7a deficiency specifically attenuated microglial neuroimmune gene expression in SOD1G93A mice and human ALS. In addition, in vivo two-photon imaging of human (h) TDP43 phagocytosis by microglia in the cortex showed that Clec7a deficiency promotes microglial phagocytosis of pathological hTDP43 by enhancing microglial process dynamics. Subsequent survival analysis further showed that selective deletion of Clec7a in microglia mitigates motor neuron degeneration and delays disease progression in SOD1G93A ALS mice. Together, our results establish that Clec7a is a key regulator in shaping disease microglial functions and promotes disease progression in ALS.

neuroscience↗

bioRxiv2026

Physical continuity at biomaterial-ECM interfaces regulates fibroblast activation via NF-κB

Fibrotic responses at biomaterial-tissue interfaces limit implant integration and regenerative healing, yet how the interaction between biomaterials and the extracellular matrix (ECM) regulates fibroblast activation remains poorly understood. Granular hydrogels including microporous annealed particle scaffolds (MAP) reduce fibrosis, while chemically and mechanically matched hydrogels do not, suggesting a dominant role for scaffold architecture. In this model, MAP scaffolds allow collagen infiltration and form physically continuous composites, whereas hydrogels exclude collagen and generate interfacial slip planes. To isolate how biomaterial architecture influences extracellular matrix (ECM) integration and fibroblast activation, we developed a reductionist in vitro model that integrates collagen type I with either microporous annealed particle (MAP) scaffolds or chemically and mechanically matched bulk hydrogels. This physical integration stabilizes collagen architecture, limits fibroblast-mediated matrix compaction, suppresses contractility, and attenuates myofibroblast transition. Fibroblasts in mechanically integrated environments exhibit reduced expression and nuclear localization of NF-{kappa}B and are enriched for quiescent phenotypes. Together, these findings identify biomaterial-ECM physical continuity as a design principle for limiting fibrotic signaling.

bioengineering↗

bioRxiv2026

PITX2C Deficiency Promotes Arrhythmogenic Remodeling via Oxidative Stress in Atrial Myocytes

AimsGenome-wide association studies have identified numerous cardiac transcription factors in association with atrial fibrillation. Amongst these transcription factors, the paired-like homeodomain transcription factor 2 (PITX2) is the strongest genetic risk variant associated with atrial fibrillation. However, the downstream mechanisms of PITX2 are not completely understood. Here, we explore the role of PITX2 in oxidative metabolism and stress as a unifying mechanism of arrhythmogenesis. Methods and resultsTo identify PITX2 mechanisms, we performed transcriptomic analysis in Pitx2c-deficient neonatal rat atrial myocytes. We identify oxidative phosphorylation as the top dysregulated pathway and direct transcriptional targets lie in mitochondrial electron transport chain complexes I and IV. Using the Seahorse Extracellular Flux Analyzer, we identified a functional decrease in oxidative metabolism in Pitx2c-deficient cardiomyocytes. As electron transport chain complexes I and IV may generate reactive oxygen species (ROS) under mitochondrial dysfunction, we quantified mitochondrial specific ROS using MitoSOX and observed an increase in mitochondrial specific ROS in Pitx2c-deficient cardiomyocytes. We additionally assessed spontaneous cardiomyocyte calcium cycling using Fluo-8AM and observed an increased frequency of pro-arrhythmogenic mechanisms including early and delayed afterdepolarizations as inferred through calcium traces. Further, we identified sarcomere disassembly including a potential role of PITX2 in regulating Titin, where Pitx2c-deficient cardiomyocytes display Titin mis-localization within the sarcomeres. To assess whether ROS drives these phenotypes, we treated neonatal rat atrial myocytes with N-acetylcysteine, a potent ROS scavenger, and observed decreased early and delayed afterdepolarizations, as well as restoration of Titin localization. ConclusionPITX2C maintains atrial metabolism and redox balance; the loss of PITX2C results in reduced oxidative metabolism and an elevation in oxidative stress that ramifies cardiomyocyte dysfunction. Treatment with antioxidant restores AF-associated phenotypes including abnormal calcium cycling and sarcomere disassembly in Pitx2c-deficient atrial cardiomyocytes. TRANSLATIONAL PERSPECTIVEGenetic variants close to the PITX2 gene associate most strongly with atrial fibrillation. This study reveals a mechanistic link between multiple AF-associated phenotypes and mitochondrial dysfunction with subsequent accumulation of reactive oxygen species downstream of PITX2. Importantly, metabolic therapies and reducing oxidative stress may present a potential clinical strategy to reverse and prevent functional and structural remodelling related to AF.

physiology↗

bioRxiv2026

Ethanol Self-Administration Reduces mGlu2/3 Protein Expression Specifically in the Nucleus Accumbens and mGlu2/3 Activation Suppresses Binge Drinking

BackgroundAlcohol use disorder (AUD) is associated with dysregulated glutamatergic signaling within mesocorticolimbic circuits that govern reinforcement and excessive ethanol intake. Group II metabotropic glutamate receptors (mGlu2/3) act primarily as presynaptic autoreceptors that regulate glutamate release. However, how voluntary alcohol intake alters mGlu2/3 expression within reward circuitry remains unclear. Methods and ResultsWe examined mGlu2/3 protein expression following a history of voluntary ethanol exposure and operant self-administration and, in separate cohorts, assessed the functional impact of group II receptor modulation on binge-like ethanol intake. Male C57BL/6J mice received two weeks of home-cage access to sweetened ethanol or sucrose followed by 35 days of operant self-administration. Immediately after the final session, tissue punches from the nucleus accumbens (NAc), amygdala, and prefrontal cortex were collected for immunoblot analysis. mGlu2/3 expression was reduced in the NAc of ethanol exposed mice with no statistically significant changes detected in the amygdala or prefrontal cortex. In separate binge-drinking cohorts, systemic administration of the mGlu2/3 agonist LY379268 reduced binge-like ethanol intake in a limited-access home-cage drinking model, whereas positive allosteric modulation of mGlu2 receptors with LY487379 was ineffective. ConclusionsVoluntary ethanol self-administration was associated with reduced mGlu2/3 protein expression in the NAc. Systemic pharmacological activation of group II receptors suppressed binge-like ethanol consumption. These findings identify mGlu2/3 dysregulation in a key reward-related brain region as a molecular adaptation associated with voluntary ethanol intake and demonstrate mechanistic regulation of binge drinking. This suggests that group II metabotropic glutamate signaling is a viable therapeutic target for treating AUD.

neuroscience↗

bioRxiv2026

Focused Ultrasound Thermal Ablation and CD40 Agonism Reprograms Breast Tumor Immunity to Drive Regression and Memory

Focused ultrasound thermal ablation (T-FUS) is a clinically accessible, non-invasive modality capable of inducing rapid tumor cytoreduction while mobilizing early immunologic danger signals. However, its capacity to synergize with potent co-stimulatory immunotherapies in breast cancer (BC) remains undefined. Here, we demonstrate that subtotal T-FUS cooperates with CD40 agonism to elicit durable, T cell-dependent tumor control across four immunologically and hormonally distinct murine BC models. Partial thermal ablation triggered canonical immunogenic cell-death signatures and acute remodeling of intratumoral myeloid populations, while expanding circulating CD4+ and CD8+ T cells. When layered onto this immunogenic milieu, CD40 markedly constrained tumor outgrowth, yielding significant reductions in tumor burden across all models and complete tumor eradication in 33% of E0771 tumors, with additional complete responses in BRPKP110 and EMT6. Efficacy required both CD4+ and CD8+ T cells, and complete responders mounted robust systemic immunity, rejecting contralateral tumor rechallenge with 100% protection and displaying persistent effector-memory T cell activation. Together, these findings establish T-FUS as an immune-potentiating partner for CD40 agonism, capable of driving durable, robust BC regression and immunological memory. This work positions T-FUS+CD40 agonism as a clinically scalable, in situ vaccination-like strategy with potential to benefit breast cancers, including luminal subtypes, that remain largely refractory to immune checkpoint blockade.

cancer biology↗

bioRxiv2026

mRNAfold: Co-optimization of Global Stability, Local Structure, and Codon Choice via Suboptimal Folding

mRNA medicines hold great promise, but designing sequences with high translation efficiency, robust in-solution stability, and manufacturability remains a major challenge due to the vast combinatorial space of synonymous coding sequences. Computational approaches such as mRNA folding algorithms have emerged as powerful tools by co-optimizing for in-solution stability and translation efficiency, yet current methods face important limitations. Here, we present "mRNAfold", an improved mRNA folding algorithm and software package that addresses these gaps by enabling efficient exploration of diverse near-optimal solutions, incorporating untranslated regions (UTRs), parallel execution, and supporting tunable control over local structural features across the mRNA. Thermodynamically optimized mRNAs from mRNAfold were more stable ({approx} 2-fold) in-solution than those generated by simple GC maximization for the same encoded protein. In addition, mRNAs designed to vary local structure near the start codon while maintaining consistent structure and codon optimality elsewhere showed a complex relationship between local structure near the start codon and protein production in cells. We observed no impact of structure in the start codon region for a set of mRNAs with high codon optimality, but it did impact protein production for a set of mRNAs with lower codon optimality. Together, these results underscore the potential of structure-aware, multi-objective design to improve mRNA medicines and offer a framework for exploring how sequence, structure, and expression are interrelated.

bioinformatics↗

bioRxiv2026

Are theoretical advances in distance-based tree learning practical for phylogenetic inference?

The phylogenetic tree of relatedness for species, viral samples, or other biological taxa is essential information for all fields of evolutionary biology. Many different statistical and computational tools for phylogeny inference are used by practicing biologists, but none take advantage of a body of theoretical work on fast-converging algorithms that guarantee correctness with high probability under particular conditions. Here, we assess the utility of one of the most advanced of these algorithms when applied in reasonable biological situations. Our simulation study shows that realistic datasets will often not meet the assumptions of the algorithm, but also that the results are relatively robust to this problem. We additionally provide guidance on how the algorithm can be deployed when the true tree is not known, which is essential for any real-world application. Overall, our intention is to bring a class of methods to the attention of the phylogenetics community, and to make the algorithmic community aware of the needs of practicing biologists.

evolutionary biology↗

bioRxiv2025

Stereoselective Degradation of Diacylglycerol Kinases Potentiate T cell Activation and Tumor Cell Cytotoxicity

Stereoselective recognition is a powerful means to differentiate selective versus non-specific activity of small molecules in complex biological systems. Here, we disclose stereochemically defined, sulfonyl-triazole inhibitors of the lipid enzyme diacylglycerol kinase-alpha (DGK), a key metabolic checkpoint for T cell effector function. Acute treatment with the covalent DGK inhibitor AHL-7160 recruited endogenous DGK to the plasma membrane in a stereoselective and isozyme-specific manner. The membrane translocation activity of AHL-7160 correlated with blockade of cellular phosphatidic acid production and potentiation of primary T cell-mediated killing of a glioblastoma cell line. Quantitative chemoproteomics revealed Y669 and K411 as sites of AHL-7160 modification on endogenous DGK in cells. Extended treatments resulted in proteasome-dependent and proteome-wide selective degradation of DGK in T cells. Collectively, these findings establish covalent DGK ligands as potent molecular glues with translational potential in immunotherapy.

biochemistry↗

bioRxiv2025

Neuromuscular Signals Shape Fatigue and Effort-Based Decision-Making in Humans

Physical fatigue influences our willingness to undertake effortful actions, yet the physiological signals driving this process are not well understood. We created a biofeedback paradigm to distinguish the effects of reduced muscle-force capacity from compensatory increases in neuromuscular activity on effort-based decision-making. Human participants made risky choices about prospective physical effort before and after repeated fatiguing exertions under two biofeedback conditions: force biofeedback, which required increased neuromuscular drive, and EMG biofeedback, which constrained the increase in neuromuscular drive. Both biofeedback conditions led to similar reductions in muscle strength and feelings of fatigue. However, we found that the Force biofeedback condition, which required compensatory neuromuscular activation, produced a significantly greater increase in the subjective cost of effort, thereby altering individuals effort-based decision-making more than EMG biofeedback. These findings demonstrate how muscle physiological processes influence feelings of fatigue and decisions to exert effort. Suggesting that fatigue may consist of separate components that collectively motivate behavior while simultaneously protecting and restoring bodily homeostasis during physical challenge.

neuroscience↗

bioRxiv2025

Neural Dynamics Underlying Repeated Learning of Visual Image Sequences

Humans possess a remarkable ability to recognize visual objects with high fidelity, supported by complex neural mechanisms underlying memory retrieval. Event-related potential (ERP) studies have identified two key neural signatures of recognition memory: the parietal old/new effect and the frontal old/new effect. Despite extensive research on these ERP components, the extent to which these components reflect distinct memory processes remains debated. In the present study, we investigated how repetitive learning modulates these ERP components. Participants repeatedly studied a fixed list of 32 real-world images across up to five study-test repetitions while EEG was recorded. Additionally, a separate set size 1 condition served as a proxy for working memory. Our results showed that with increased repetitions, the parietal old/new effect exhibited enhanced amplitude and earlier peak latency, reflecting more efficient retrieval of well-learned memories. In contrast, the frontal old/new effect remained unchanged in both amplitude and timing. These findings suggest that the parietal old/new effect is a sensitive neural marker of learning-related changes in long-term memory representations, while the frontal effect is less influenced by repetition. Additionally, despite similarly high accuracy between the well-practiced set size 32 condition and the set size 1 working memory condition, both parietal and frontal old/new effects peaked significantly earlier for set size 1, suggesting that access to working memory is substantially faster than even well-practiced long-term memory. Together, our results highlight the unique role of the parietal old/new effect, but not the frontal old/new effect, in repetitive learning, despite both components being important for successful recognition of learnt visual stimuli.

neuroscience↗

bioRxiv2025

Persistent Classical and Atypical Memory B Cells Underlie Heterogeneous Vaccine Responses in Ocrelizumab-Treated Multiple Sclerosis

Background and ObjectivesPatients with multiple sclerosis (pwMS) treated with ocrelizumab (OCR), a B-cell-depleting therapy, exhibit heterogeneous humoral responses to SARS-CoV-2 mRNA vaccination. The mechanisms underlying this variability remain incompletely understood. We performed a longitudinal analysis of B-cell subset dynamics and antigen-specific T cell responses in OCR-treated pwMS and healthy controls to determine how immune cell composition, timing of OCR infusion, and lymphocyte dynamics influence humoral response outcomes. MethodsBased on post-vaccination anti-Spike IgG titers measured by multiplex bead immunoassay, pwMS were categorized as super-responders (SR), responders (R), or non-responders (NR). A 35-marker spectral flow cytometry panel was used to characterize T- and B-cell subsets longitudinally, at baseline and following stimulation with a SARS-CoV-2 peptide pool. ResultsCD4+ and CD8+ T cell populations were preserved across OCR-treated pwMS, and SARS-CoV-2-specific T cells remained detectable for more than 6 months after vaccination. In contrast, residual B-cell subset composition distinguished responders from non-responders. DN2-like B cells (CD19+CD27-IgD-T-bet+CD11c+CXCR5-) persisted despite repeated OCR infusions and were enriched in SR compared with NR. Repletion of mature naive B cells in peripheral blood correlated with time since last OCR infusion and with stronger humoral immune responses. ConclusionsB-cell subsets that resist OCR-mediated depletion may contribute to vaccine responsiveness in OCR-treated pwMS. Altered repletion kinetics of naive B cell subsets in non-responders suggest that specific B-cell populations may serve as predictive biomarkers of vaccine-induced humoral immunity, despite preserved T-cell responses.

immunology↗

bioRxiv2025

Adipocytes are dispensable in shaping the ovarian cancer tumor microenvironment in the omentum

The omentum, a specialized adipose tissue within the peritoneum, is a primary niche for ovarian cancer (OC) dissemination during peritoneal carcinomatosis. Traditionally, omental adipocytes are thought to promote OC growth by supplying lipids, supported by evidence that global FABP4 deficiency reduces tumor progression. Here, we generated mice lacking mature adipocytes in the peritoneum, including the omentum. ID8p53-/-Brca2-/-, BPPNM, and KPCA OC cells retained a propensity to seed regions typically associated with adipocytes, even without mature adipocytes. However, the lack of mature adipocytes did not suppress peritoneal OC expansion, whereas removing the adipocyte-free omentum did. Murine and human single-cell RNA sequencing revealed that endothelial FABP4 was high in the omentum. Indeed, endothelial cell-selective deficiency of FABP4 reduced OC growth in the peritoneum. These findings prompt a reevaluation of adipocyte contributions to OC progression and suggest a key role of the omental vasculature in supporting OC metabolic growth.

cancer biology↗