Biology subjects

Hoffmann, D.

Publications and source records attributed to Hoffmann, D..

At least 19 recordsLinked to original sources

bioRxiv2026

Bat-borne influenza A H9N2 virus shows species-specific replication and transmission

Bat-borne H9N2 IAV (bat H9N2), initially detected in bat feces in Egypt in 2017, has recently attracted attention because of its unexpected pre-pandemic properties, including airborne transmission between ferrets and efficient replication in human lung explant cultures. However, its host range and potential reservoir hosts remain poorly defined, particularly with respect to additional bat hosts and mammalian or avian mixing-vessel species. Here, we compare the susceptibility of two pteropodid bat species, Rousettus aegyptiacus and Eidolon helvum, and additionally assessed pigs and quails following intranasal inoculation with bat H9N2. Juvenile R. aegyptiacus showed only low-level viral replication and shedding, largely restricted to the upper respiratory tract, and did not show transmission to contact bats. In contrast, both juvenile and adult E. helvum, despite showing no clinical signs, showed high-level viral replication and shedding in the upper respiratory tract, with efficient and early transmission to contact bats. Viral RNA was most abundant in the respiratory turbinates, the nasopharyngeal meatus and the tracheal epithelium, where it was associated with moderate to severe necrotizing rhinitis and tracheitis. The lower respiratory tract was less involved, with viral RNA confined to scattered bronchioles and associated with focal necrotizing bronchiolitis. Other organs, including the gastrointestinal tract, lacked histologic lesions and viral RNA labeling. In pigs and quails, intranasal inoculation did not result in detectable replication, transmission, or seroconversion. Our findings demonstrate marked differences in the susceptibility to bat H9N2 between the two fruit bat species tested and identify E. helvum as a highly susceptible host capable of rapid and efficient transmission. Conversely, pigs and quails were not susceptible, suggesting that additional viral adaptations may be required to allow for a productive infection in these species.

microbiology↗

bioRxiv2026

Supramodal Coding of Detection and Confidence in the Human Cortex

Perception is inherently multisensory, yet it remains unclear whether the brain detects stimuli and evaluates confidence in these detections using circuits shared across senses or circuits specific to each modality. Prior evidence is limited: scalp electrophysiology cannot localize where a shared code operates, whereas functional imaging cannot resolve its timing. We recorded intracranial activity (stereoelectroencephalography) in eight patients with epilepsy who performed a near-threshold audiovisual detection task in which they reported, on each trial, whether a visual, auditory, or audiovisual stimulus was present and rated their confidence, both overall and separately for each modality. Analyzing high-gamma activity at the single-channel and region-of-interest levels, we found that stimulus detection involved a broadly distributed, largely supramodal set of cortical regions responding regardless of modality, including the insula, dorsomedial prefrontal cortex, and superior temporal gyrus. Multivariate decoders trained to distinguish detected from undetected stimuli in one modality generalized to the other modality, indicating a shared detection code within these regions. Confidence relied on a more mixed architecture but was also substantially supramodal. Finally, the auditory cortex encoded confidence information about its non-preferred (visual) modality, with a similar effect in the visual cortex for auditory confidence, suggesting that the involvement of sensory cortices in confidence is not confined to its preferred input.

neuroscience↗

bioRxiv2026

Uncertainty-aware quantitative analysis of the structure and dynamics of T cell receptor repertoires

Diversity and dynamics of immune cell receptor repertoires (IRRs) are two factors at the functional heart of adaptive immunity that together make IRRs difficult to grasp. Moreover, measurements are compounded by various sources of experimental noise. Here we propose a computational framework (ClustIRR) for uncertainty-aware quantitative analysis of IRR structure and dynamics. ClustIRR maps multiple IRRs across replicates, time points, or conditions onto a joint graph induced by immune receptor sequence similarity. It then detects communities on the joint graph (CJs). Based on CJs as reference structures across IRRs, ClustIRR then performs quantitative Bayesian analyses of differential CJ occupancy. Additionally, ClustIRR integrates single-cell gene expression data to link community expansion with transcriptional activation signatures. We demonstrate the capabilities of ClustIRR with the joint analysis of multiple T cell receptor repertoires in several example applications: (1) quantitative changes due to antigen challenge, (2) longitudinal dynamics during cancer immunotherapy, (3) V(D)J recombination biases in human vs murine repertoires that pre-adapt IRRs for pathogen responses. ClustIRR is freely available as open source software from the bioconductor repository.

immunology↗

bioRxiv2026

Long-term Humoral Immune Dynamics After SARS-CoV-2 Vaccination and Infection in Healthcare Workers: The VaCoMRI Study

ObjectivesThe VaCoMRI study tracked a healthcare worker cohort from 2020 through June 2024 to characterize the long-term sustainability of vaccine- and infection-induced SARS-CoV-2 immunity. MethodsFollowing an initial anti-nucleocapsid (N) IgG screening of 4,554 employees in early 2020, participants were monitored regularly from the BNT162b2 rollout (December 2020). Serum collected at predefined intervals after vaccination and breakthrough infection (BTI) was analyzed for anti-N, quantitative anti-spike (anti-S) IgG, and surrogate viral neutralizing antibody (sVNT) titers. ResultsOver a median follow-up of 1,180 days, 142 healthcare workers contributed longitudinal samples; 66.2% experienced one BTI and 14.1% a second. In previously seronegative individuals, anti-N titers decreased 2.3-fold between 3 and 6 months post-first BTI, with seropositivity dropping from 82% to 40.4% (median time to seronegativity: 179 days). Conversely, prior anti-N seropositivity was associated with 4.5-fold higher anti-N IgG levels during follow-up, and a second BTI led to 3-fold higher titers at 3 months. Before BTI, the third vaccine dose significantly enhanced antibody persistence versus the second dose; at 9 months, titers remained 7.2-fold higher for sVNT and 3.9-fold higher for anti-S IgG. Initial seropositivity also predicted 2.9-fold higher sVNT levels during follow-up. ConclusionsRepeated vaccination and infection synergistically induced robust, durable spike-directed hybrid immunity. Conversely, rapid anti-N IgG waning severely limits its reliability for the retrospective serosurveillance of SARS-CoV-2 exposure in occupational settings.

microbiology↗

bioRxiv2026

Spatial Compartmentalization of TCR Repertoires Between Primary Melanomas and Sentinel Lymph Nodes Reveals Distinct Clonal Architectures and Shared Antigen Recognition

Primary tumors and their sentinel lymph nodes are functionally linked sites of anti-tumor immunity, yet how T cell receptor (TCR) repertoires are organized across these compartments remains incompletely understood. We thus performed TCR{beta} sequencing on paired primary melanoma tumors and sentinel lymph nodes from 24 treatment-naive patients to quantify TCR repertoire diversity and clonal architecture as markers of antigen-driven selection. Primary tumors exhibited markedly reduced TCR diversity and pronounced clonal dominance compared with matched lymph nodes, consistent with selective expansion of tumor-reactive T cells. Tumor-associated clonotypes displayed significantly longer CDR3 sequences driven by increased non-templated nucleotide insertions, a feature associated with neoantigen recognition, and showed biased TRBV and TRBJ gene usage indicative of CD8+ T cell enrichment. Annotation against known melanoma differentiation and cancer testis antigens identified only a small fraction of clonotypes with characterized specificities, and fewer than 10% of these were shared between tumors and lymph nodes, suggesting that most expanded tumor clonotypes recognize patient-specific antigens. To identify shared immune features beyond individual clonotypes, we applied ClustIRR to build a joint graph linking clonotypes across repertoires by CDR3 sequence similarity and detected Communities on the Joint graph (CJs) to uncover recurrent TCR sequence motifs. Differential occupancy analysis identified distinct CJs segregating tumors and lymph nodes, including a limited number of recurrent CJs targeting MART-1 epitopes, while the majority were patient-specific. Together, these data define spatially structured TCR repertoire architectures in human melanoma and establish a scalable framework for interrogating tumor-immune interactions. eLife DigestMelanoma is a skin cancer harboring many UV-associated mutations, making it recognizable to the immune system. T cells attack cancer using specialized molecular structures called T cell receptors (TCRs). They are frequently referred to as specific keys that only fit into the respective locks, i.e. HLA molecules presenting the target antigen. Surgeons often remove both the tumor and the tumor draining lymph node (aka sentinel lymph node). The tumor is where T cells directly fight cancer, while the sentinel lymph node is where new anti-tumor T cells are first activated. How these two sites coordinate immune surveillance is not completely understood. Here, Kitanovski and colleagues sequenced TCRs from paired tumors and sentinel lymph nodes obtained from melanoma patients. These analyses demonstrated that primary tumors have dramatically reduced TCR diversity, dominated by a few massively expanded T cell clones, whereas sentinel lymph nodes contain broad, balanced repertoires. This reveals intense local selection within the tumor-a small set of tumor-specific T cells expand repeatedly while the lymph node preserves diverse immune reserves. Examining TCR structure revealed a second key difference. Tumor-infiltrating T cells possess on average slightly longer CDR3 loops-the region contacting antigens-especially among dominant clones. These longer loops arise from random nucleotide insertions. Prior work shows that self-antigen-specific T cells have shorter CDR3s due to thymic constraints, whereas T cells recognizing tumor-specific mutation-derived neoantigens escape these restrictions and have longer CDR3s. Thus, tumor TCRs appear tailored for recognizing patient-specific neoantigens. The authors could only use TCRs matching known databases for shared melanoma antigens like MART-1 to identify TCR-specific epitopes; most tumor-expanded TCRs could not be annotated because patient-specific neoantigens are not in public databases. This limitation itself is informative- most expanded tumor TCRs likely target private neoantigens. Grouping TCRs by sequence similarity into "communities" revealed striking patterns: sentinel lymph nodes showed conserved community composition across patients, consistent with responses to common viruses, while tumor repertoires were highly individualized, reflecting each tumors unique mutations. These findings establish how anti-melanoma immunity is spatially organized: sentinel lymph nodes contain diverse T cell landscapes, while in primary tumors melanoma-infiltrating T cells appear to have undergone intense selection for neoantigen recognition. This provides a foundation for using TCR features as biomarkers and designing personalized T cell therapies.

cancer biology↗

bioRxiv2026

First evaluation of a human DPP4 transgenic hamster model for MERS-CoV pathogenesis and transmission

MERS-CoV poses a constant pandemic risk, as its viral lineages continue evolving, and zoonotic spillover events could lead to random viral polymorphisms that might lead to human adapted variants. Currently, no small animal model reliably recapitulates both disease progression and transmission dynamics, which are critical aspects for counter-viral measures like vaccine development. Although the Syrian hamster is an optimal animal model for SARS-CoV-2 infection and transmission, it is naturally resistant to MERS-CoV infection. Dipeptidyl peptidase-4 (DPP4) is the functional receptor for MERS-CoV infection, and is highly expressed in human kidney, intestine, liver, and lung tissues. Here, we evaluated the suitability of a human DPP4 (hDPP4) transgenic Syrian hamster model for MERS-CoV research. We used two different MERS-CoV strains (EMC/2012 and D10540/2023) for intranasal inoculation of hamsters. Both strains replicated efficiently, led to comparable severe clinical outcomes, and had similar viral transmission efficiencies. MERS-CoV RNA and nucleoprotein antigen were mainly detected in the brain and the respiratory tract. In summary, we validated a novel hDPP4-transgenic hamster as a suitable model for MERS-CoV infection enabling vaccine and transmission research.

microbiology↗

bioRxiv2026

Quantifying Treatment Resistance in Mixtures of Gastrointestinal Stromal Tumor Cells with BARMIX

Targeted therapies in gastrointestinal stromal tumors (GIST) often fail due to heterogeneous resistance mutations arising across metastatic sites. Efficient, rational design of mutation-specific therapies requires the ability to quantify treatment resistance across many genotypes in parallel. Here, we present BARcode MIXture analysis (BARMIX), a platform combining multiplexed experiments with DNA-barcoded cancer cell mixtures in vitro and in vivo, and a probabilistic framework for quantitative assessment of genotype-specific treatment resistance. BARMIX efficiently and accurately recapitulated known clinical resistance patterns in GIST and matched resistance measurements from individual cell lines in vitro and in vivo. This experimental-computational approach provides a scalable and broadly applicable strategy for quantifying treatment responses in complex cell populations, enabling systematic preclinical testing of new drugs and combinations to identify mutation-specific therapeutic options for precision oncology in GIST and beyond.

systems biology↗

bioRxiv2026

One and Done: A safe, adaptable single-cycle SARS-CoV-2 vaccine platform blocks XBB.1.5 infection and transmission

A next-generation SARS-CoV-2 vaccine must address the currently inadequate prevention of virus transmission, particularly against emerging variants of concern, a challenge that none of the licensed commercial vaccines fully meet. Effective control of respiratory pandemics necessitates vaccines that 1) can be rapidly adapted, 2) have high patient compliance with simple and non-invasive administration, and 3) block transmission in a virus challenge. We describe here the characterization of an updated single-cycle SARS-CoV-2 vaccine candidate (scVac), engineered as a replication-defective virus with targeted deletions of the E gene and ORF6 and ORF7a, along with a truncation of ORF3a. The candidate carries an Omicron XBB.1.5 Spike (scVacXBB), maintaining all essential antigenic properties. The vaccine demonstrated an excellent safety profile in K18-hACE2 transgenic mice, the most sensitive virulence model, with no clinical signs or adverse events observed. In the Syrian hamster model, potent systemic and mucosal immune responses were induced, along with a strong neutralizing antibody response. Notably, there was no virus transmission to co-housed naive animals, which outperforms a bivalent Omicron mRNA vaccine reference. Our results demonstrate that scVacXBB-induced immunity not only prevents disease but also effectively blocks transmission. Furthermore, the successful introduction of the XBB.1.5 Spike protein into the scVac platform demonstrates the pipelines ability to adapt quickly to any emerging variant. These findings highlight the potential of this single-cycle concept as a next-generation COVID-19 vaccine, offering robust protection with a strong safety profile.

immunology↗

bioRxiv2026

Heparan sulfate-function is essential for Integrin-dependent cell-matrix interactions and regulates glycosaminoglycan synthesis synthesis through YAP

Extracellular matrix (ECM) is the main component of cartilage, making it an ideal environment to study cell-matrix interactions. Among ECM constituents, heparan sulfate (HS)-carrying proteoglycans (PGs) are of particular interest since they are not only structural components but are also involved in cell matrix adhesion and signalling processes. We previously demonstrated that transgenic mice with a clonal loss of HS synthesis in chondrocytes (Col2-rtTA-Cre;Ext1e2fl/e2fl) develop clusters of enlarged cells in the articular cartilage (AC), which are surrounded by a glycosaminoglycan (GAG)-rich ECM. This led to the questions how HS regulate the molecular composition and mechanical properties of the ECM, how they sense alterations in the HS structure and how they respond to it. We stained tissue sections of Col2-rtTA-Cre;Ext1e2fl/e2f animals and detected increased levels of chondroitin sulfate (CS), Aggrecan (Acan), Perlecan (Pcan), Matrilin (Matn)-3 and-4, Collagen type II (Col2) and Col9, while Col12 was abolished in the HS-deficient clusters. We assessed the stiffness of the mutant matrix by Atomic Force Microscopy (AFM) and found that it was markedly softer than the surrounding, HS-containing tissue. Likely in response to this altered texture, HS-deficient clones showed increased protein levels of Integrin pathway components. To model a loss of HS-function in vitro, we treated murine embryonic fibroblasts (MEFs) with the HS-antagonist Surfen. Treatment during cell adhesion resulted in impaired cell-substrate adhesion, increased formation of filopodia-like membrane protrusions, decreased cell polarisation and migration, reduced formation of FA and SF, and a translocation of YAP into the cytoplasm. Similarly, we observed reduced cell polarisation in HS-deficient CHO pgsD-667 cells, which could not be rescued by external presentation of HS. When MEFs were treated with Surfen after the completion of the initial cell adhesion process, inhibition of HS-function led to an increased formation of FA and SF, in line with the increased levels of Integrin pathway components observed in HS-deficient chondrocytes in vivo. We detected high levels of Yes1-associated protein (YAP) in the HS-deficient clusters, and we investigated the effect of YAP modulation on high density micromass cultures from primary murine chondroprogenitors. YAP activation induced an increased GAG synthesis similar to Surfen, while YAP inactivation partially abolished the effect of Surfen, showing that YAP acts downstream of HS function and controls GAG synthesis. Taken together, we demonstrated that HS-function is essential for Integrin-dependent cell-matrix interactions. Information on the impaired cell matrix adhesion upon loss of HS is conveyed into the nucleus via YAP, which at least partially controls the synthesis of GAGs in chondrocytes.

cell biology↗

bioRxiv2026

Codon Deoptimization of Multispecific Biologics Reduces Mispairing During Transient Mammalian Protein Expression

Codon optimization is utilized in biologics design to maximize protein expression. Selecting the host organisms most frequently used codons for each amino acid can significantly enhance recombinant protein expression yields. However, non-optimal codons in mRNA can be critical for functional protein production through inducing pauses in or attenuating protein translation. In our study, we have investigated the effect of deoptimizing serine codons in biologics by shifting them from the five most frequently used codons to the least (TCG). Rare serine codons were strategically inserted into the coding sequences of the constant regions in a trispecific antibody (Protein 1), a bispecific antibody (Protein 2), and multiple non-proprietary bispecific antibodies. We observed that inserting 1-2 rare serine codons within an open reading frame led to expression changes that reduced the formation of mispaired 2x light chain and half-molecule species. Protein purity was drastically increased by incorporating two deoptimized serine codons into a single chain. Notably, we observed a negative correlation between total protein expression yield and final product purity. Taken together, our work demonstrates that incorporation of deoptimized serine codons into a single chain can significantly influence multispecific biologic pairing and enhance final product purity. Our findings align with existing literature showing that rare codon usage modulates translation kinetics and protein folding. Future investigation is warranted to enable a priori identification of the rate-limiting chain in multispecific biologics, thereby guiding strategic codon deoptimization prior to expression.

bioengineering↗

bioRxiv2026

Development of a multi-species luciferase-based double antigen ELISA for the detection of antibodies against Influenza A virus H5 clade 2.3.4.4b

The highly pathogenic avian influenza viruses (HPAIV) of subtype H5N1 represent a major threat to animal and public health. The current panzootic with H5 clade 2.3.4.4b has caused numerous, widespread outbreaks in various domestic and wild avian species with high mortalities, massive losses and a high frequency of spillover events to unexpected novel mammalian hosts such as dairy cows. The global H5N1 situation raises serious concerns about zoonotic risks due to effective mammal-to-mammal transmission. Therefore, it is critical to increase surveillance intensity of a broadened species range, particularly at the human-animal interface. For this purpose, reliable and cost-effective serological tools that are easy to perform and suitable for high-throughput screenings are critically needed. The newly developed double antigen ELISA format employing a luminescence-based detection technology has demonstrated to comply with such prerequisites. The assay allowed the detection of H5-specific antibodies even early after infection or vaccination in a wide range of birds and mammals including humans. It further demonstrated superior analytical sensitivity and high specificity for antibodies directed against H5 hemagglutinin of clade 2.3.4.4b as no cross-reactivity with other hemagglutinin subtypes was observed. Thus, the assay represents a valuable contribution to existing serological diagnostic tests for a clade-optimized detection of influenza A virus antibodies in a broad range of species. ImportanceThe ongoing HPAIV H5N1 panzootic has caused numerous outbreaks in domestic and wild animals with frequent spillover events to unexpected host species, which underscores the importance of an intensified surveillance. However, sensitive and specific multi-species serological assays represent a major gap. For this purpose, we developed a novel double antigen ELISA which employs an innovative luminescence-based read-out strategy. The test allowed a highly sensitive and specific detection of H5-specific antibodies even early after infection or vaccination in a wide range of avian and mammalian species including humans. It therefore represents a significant contribution to improving species-independent serological diagnostic tools for the detection of influenza A virus antibodies.

microbiology↗

bioRxiv2025

Uncertainty-aware quantitative analysis of high-throughput live cell migration data

Accurate quantification of cell migration velocity is essential for understanding biological processes such as development, immune function, and cancer metastasis. High-throughput migration assays generate complex, hierarchically structured datasets with technical noise, batch effects, and biological variability, introducing uncertainty into velocity estimates that current methods often fail to quantify. To address this, we present cellmig, a computational tool using Bayesian hierarchical modeling to separate biological signals from technical variation while explicitly quantifying uncertainty in migration velocity. cellmig provides a robust framework for analyzing migration assays, including dose-response studies and large-scale screens with biological and technical replicates. By modeling biological variability and technical confounders within a unified Bayesian framework, it estimates condition-specific effects (e.g., drug effects) on cell velocity with probabilistic uncertainty intervals, avoiding common pitfalls of null-hypothesis testing. Its generative models simulate migration under various assumptions, aiding experimental planning. Overall, cellmig improves reproducibility and comparability across studies, offering deeper biological insight.

bioinformatics↗

bioRxiv2025

Multiplets in scRNA-seq data: extent of the problem and efficacy of methods for removal

Multiplets--droplets that capture more than one cell--are a known artefact in droplet-based single-cell RNA sequencing (scRNA-seq), yet their prevalence and impact remain underestimated. In this study, we assess the frequency of multiplets across diverse publicly available datasets and evaluate how well commonly used detection tools are able to identify them. Using cell hashing data to determine a lower bound of the true multiplet rate, we demonstrate that commonly used heuristic estimations systematically underestimate multiplet rates, and that existing tools--despite optimized parameters--detect only a small subset of cell-hashing multiplets. We further refine a Poisson-based model to estimate the true multiplet rate, revealing that actual rates can exceed heuristic predictions by more than twofold. Downstream analyses are significantly affected by multiplets: they are not confined to isolated clusters but are distributed throughout the transcriptional landscape, where they distort clustering and cell type annotation. Using both quantitative and qualitative approaches, we visualize these effects and show that cell-hashing-informed multiplet removal eliminates artefactual clusters and improves annotation clarity, whereas computationally detected multiplets fail to fully remove artefacts in the most common experimental contexts. Our findings confirm that multiplet contamination remains a pervasive and under-addressed issue in scRNA-seq analysis. Since most datasets lack multiplexing, researchers must often rely on heuristics and limited tools, leaving many multiplets unidentified. We advocate for more robust multiplet-detection strategies, including multimodal validation, to ensure more accurate and interpretable scRNA-seq results.

bioinformatics↗

bioRxiv2025

Population and adaptation history of 739 Thlaspi arvense natural accessions

Pennycress (Thlaspi arvense) is a promising intermediate oilseed crop, producing oil suitable for conversion to biofuels--including aviation fuels. While domestication efforts are ongoing, a deeper understanding of the genetic architecture of traits is crucial for informing future breeding efforts. Here, we conducted the largest genomic and phenotypic survey of pennycress to date, analyzing 739 accessions collected across four continents. Leveraging whole-genome sequencing and field-collected phenotypes, we characterized the standing genetic variation underlying key agronomic traits and climate resilience. Our findings revealed multiple independent migration events to North America, with substantial genetic admixture. We identified homologs of Arabidopsis thaliana flowering-time genes that contribute to adaptation and demonstrated the agronomic benefits of winter-type pennycress. Furthermore, through multi-season field trials, we identified a genomic region containing a cluster of mTERF genes strongly associated with green canopy coverage, a critical trait for biomass retention and yield stability. These insights provide a genomic roadmap for accelerating pennycress domestication and improving its resilience to climate variability.

genomics↗

bioRxiv2025

Corrections in single cell migration path in vivo are controlled by pulses in polar Rac1 activation

Directed migration of single cells is central to a large number of processes in development and adult life. Corrections to the migration path of cells are often characterized by periodic loss of polarity that is followed by the generation of a new leading edge in response to guidance cues, a behavior termed run and tumble. While this phenomenon is essential for accurate arrival at migration targets, the precise molecular mechanisms responsible for the periodic changes in cell polarity are unknown. To investigate this issue, we employ germ cells in live zebrafish embryos as an in vivo model and show that a tunable molecular network controls periodic pulsations of Rac1 activity and actin polymerization. This process, which we term polar pulsations, is responsible for the transitions between the run and tumble phases. In addition, we provide evidence for the role of apolar blebbing activity during tumble phases in erasing the memory of the previous front-back polarity of the migrating cell. To understand how the molecular components give rise to this distinct behavior, we develop a minimal mathematical model of the biochemical network that accounts for the observed cell behavior. Together, our in vivo findings and the mathematical model suggest that a pulsatory signaling network regulates the accuracy of individual cell migration.

cell biology↗

bioRxiv2025

High LET Radiation: A Novel Strategy to Overcome Tumor Microtubes -Mediated Radioresistance in Glioblastoma

PurposeTumor cell networks formed by tumor microtubes (TMs) are thought to drive therapy resistance in glioblastoma (GB). X-ray irradiation enhances TM formation, thereby increasing radioresistance. We hypothesize that high linear energy transfer (LET) particle radiotherapy is less affected by TM-mediated resistance due to its reduced reliance on indirect DNA damage. This study explores the impact of LET-induced DNA damage on TMs formation and GB survival Material and MethodsFormation of TMs was investigated in the primary patient derived glioblastoma stem-like cell lines (S24 and T269) irradiated with different LET, ranging from 3 - 107 keV/{micro}m, across dose series (1, 2, 4, 6 Gy) of clinical proton, helium, and carbon ion beams. TM networks and DNA damage patterns, specifically {gamma}H2AX foci, were visualized using fluorescence microscopy. Cell survival was evaluated through clonogenic survival assays. ResultsThe formation of TMs, radiation-induced nuclear DNA damage repair foci, and GB cell survival were correlated with a gradual increase in LET. Consistent with conventional photon/X-rays, low-LET proton irradiation promoted TMs formation in a dose-dependent manner. In contrast, an anti-correlation between LET and TMs induction was found, i.e., a decreased network connectivity with gradual increase of LET and formation of complex DNA damage. Consequently, LET increase correlated with reduced cell survival, with the most pronounced cell killing observed after high-LET carbon irradiation. Moreover, the inverse correlation between LET and TMs density was further confirmed for a broad range of LET modulated within the carbon ion irradiation. ConclusionThis is the first report on the relevance of LET as a novel mean to overcome TMs network-mediated radioresistance in GB, with ramifications for the clinical translation of high-LET particle radiotherapy to further improve outcome in this still devastating disease.

cancer biology↗

bioRxiv2025

Detection of low pre-existing humoral immunity against influenza virus H5N1 clade 2.3.4.4b in unexposed individuals

The spill-over of Influenza A virus H5N1 clade 2.3.4.4b from cattle to humans highlights the risk of a human H5N1 pandemic. Given the impact of pre-existing immunity on the course and severity of viral infections, we comprehensively assessed the humoral immunity against the H5N1 A/Texas/37/2024 isolate in H5N1-naive individuals. To this end, we performed complementary binding and neutralization assays on 66 subjects and ranked activities among a panel of 76 influenza A virus isolates. We detected low but distinct cross-neutralizing titers against A/Texas/37/2024 with a 3.9 to 15.6-fold reduction compared to selected H1N1 or H3N2 strains. By cloning and evaluating 136 monoclonal antibodies from memory B cells, we identified potent A/Texas/37/2024-neutralizing monoclonal antibodies in five out of six investigated individuals. These antibodies cross-neutralize H1, compete with antibodies targeting the HA stem, and protect mice from lethal H5N1 challenge. Our findings demonstrate partial pre-existing humoral immunity to A/Texas/37/2024 in H5N1-naive individuals.

immunology↗

bioRxiv2024

Morphological profiling in human dopaminergic neurons identifies mitochondrial uncoupling as a neuroprotective effect

Parkinsons disease (PD) involves multiple pathological processes in midbrain dopaminergic (mDA) neurons, including protein degradation defects, vesicular trafficking disruption, endolysosomal dysfunction, mitochondrial issues, and oxidative stress. Current PD models often lack complexity and focus on single phenotypes. We used patient-derived SNCA triplication (SNCA-4x) and isogenic control (SNCA-corr) mDA neurons, applying high-content imaging-based morphological profiling to identify and rescue multiple phenotypes. Screening 1,020 compounds, we identified top-scoring compounds that restored healthy profiles in SNCA-4x neurons, increasing Tyrosine hydroxylase (TH) and decreasing -synuclein (Syn) levels. Several hits were linked to mitochondrial biology. Tyrphostin A9, a mitochondrial uncoupler, and several of its structural analogues decreased ROS levels, normalized mitochondrial membrane potential, and increased respiration. Western blotting confirmed that Tyrphostin A9 reduces Syn levels. Our study highlights the neuroprotective potential of mild mitochondrial uncoupling in mDA neurons.

neuroscience↗