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Jung, J.

Publications and source records attributed to Jung, J..

At least 55 records · Page 3Linked to original sources

Single-cell neural network classifiers reveal that PM21 NK cell expansion is dependent on B cell signaling

In the field drug development ML/AI methods are being applied to improve drug production speed, costs, and reliability. In allogenic NK cell therapy production, one of the biggest challenges is the inherent variability in the donors that provide the starting material for NK cell expansion. In this study we performed PM21-mediated NK cell expansion on 26 donors, and in parallel performed single-cell transcriptomics on the same donor sample prior to expansion. Canonical differential expression analysis and cell state abundance did not highlight any significant difference between donors with high and low NK cell expansion yield. Instead, training neural networks classifiers for high-yield donors enabled identifying several highly predictive models with perfect cross-validation recall. Further investigation of the most predictive models unveiled a previously unknown role for B cell in supportive NK cell expansion. Overall, this study represents a blueprint for combining deep phenotyping and machine learning methods to unveil novel biology and improve the quality and speed of delivery of cell therapeutics to patients.

systems biology↗

Superoxide dismutases shape manganese stoichiometry in Southern Ocean diatoms

Elemental stoichiometry of biomass is a focal point that connects different biogeochemical cycles. Yet, the mechanistic underpinnings of elemental stoichiometry are poorly quantified in many cases. We combined targeted and untargeted metaproteomics, Bayesian statistical modelling, and geochemical measurements to quantify the contribution of specific proteins to metal stoichiometry in natural populations of Southern Ocean diatoms. Our analyses indicate that a substantial amount of non-photosynthetic manganese (Mn) in diatoms in an Antarctic polynya can be attributed to superoxide dismutases ([~]0.7 {micro}mol Mn: mol Carbon; [~]20% of the total cellular Mn quota). We then used cultures and proteomic profiling of the key polar diatom Fragilariopsis cylindrus to identify environmental controls on superoxide dismutases, and discovered that iron concentration has little influence on the abundance of two Mn superoxide dismutases, while Mn limitation induces the depletion of these Mn superoxide dismutases and an accompanying increase of nickel superoxide dismutase. Overall, we combined metaproteomic approaches to quantify proteomic composition and connected these measurements to metal-to-carbon ratios and their responses to metal availability. Because metal quotas are key parameters in some biogeochemical models, our approach provides a direct mechanism for informing ecosystem-scale models with molecular measurements.

microbiology↗

Beta burst waveform extraction using novel 4He-OPMs

Studying the electrophysiology of motor preparation and execution is challenging due to the restrictions often placed on the experimental paradigm by the imaging modality. MEG is well suited to track temporal brain dynamics while offering good spatial resolution, but requires an absence of head motion due to the fixed helmet and associated cryogenic cooling system. Here we used novel, room temperature, wearable optically pumped magnetometers using Helium to measure the MEG in a motor preparation and execution task and compare this with classic SQUID-MEG. Beta band activity (13-30Hz) is widely associated with motor activity, and it has become widely accepted that beta activity occurs in bursts rather than sustained activity. Here we used a novel beta burst extraction pipeline to look at not only the occurrence of the beta bursts across the timecourse of motor preparation and execution, but at the specific waveforms of the beta burst that evolve over time. Results show that specific beta burst waveforms show strong task relevant modulations of burst rate. Beta burst waveforms extracted using Helium-OPMs were very similar to those extracted using SQUID-MEG, with comparable modulations of burst rate over time for specific waveforms. This shows a promising step to obtaining high quality electrophysiological data in less restricted paradigms.

neuroscience↗

Developmental Plasticity and Stromal Co-option Shape a Pituitary Neuroendocrine Tumor Transcriptional Continuum

Pituitary neuroendocrine tumors (PitNETs) are common intracranial neoplasms with complex biology underpinned by unresolved cellular origins, molecular heterogeneity, and microenvironment interactions. Here, we employ single-nuclei RNA-sequencing (snRNA-seq) of 419,874 cells from human normal pituitaries and PitNETs with spatial transcriptomics to resolve these challenges. We identify multi-hormonal neuroendocrine cells in both normal and tumor tissues, originating as early pseudotime intermediates from pituitary stem cells, revealing an inherent plasticity that blurs traditional lineage boundaries. PitNETs exhibit a transcriptional continuum across subtypes, challenging their classification into discrete categories. Trajectory analysis uncovers divergent cellular origins: silent gonadotroph adenomas (SGAs), prolactinomas, silent corticotroph adenomas (SCAs), and Cushings adenomas are closely linked to differentiated neuroendocrine cells, while somatotroph and null cell adenomas (NCAs) appear to derive more directly from adult stem cells. Tumor cells co-opt robust cell-cell communication networks found in normal adult neuroendocrine cells. Spatial profiling further demonstrates that perivascular niches enhance tumorigenicity through angiogenic and epithelial-mesenchymal transition programs. Our work redefines PitNETs as ecosystems shaped by developmental plasticity and microenvironmental crosstalk, offering a roadmap for future therapies targeting lineage fluidity and stromal dependencies.

cancer biology↗

Murine peritoneal macrophages undergo female-specific remodeling with aging

Aging is a complex process characterized by a progressive decline in physiological functions. Immune function is strongly influenced by biological sex, affecting both innate and adaptive responses. Here, we investigated the effects of age and sex on mouse peritoneal immune cells and identified macrophages as the top affected cell type. Macrophages, as central components of the innate immune system, play critical roles in homeostasis maintenance and infection response. We found that aging induces sex-specific remodeling of mouse peritoneal macrophage omic landscapes, which is accompanied by female-specific age-related functional remodeling (i.e. decreased phagocysis, increased glycolysis). We show that age-related changes in circulating estrogen levels likely drive aspects of female-specific macrophage age-related changes, specifically age-related phagocytosis decline. By leveraging our multi-omic dataset, we identify transcription factors whose female-specific age-regulation may drive female-specific age-related changes in peritoneal macrophage phenotypes. Interestingly, Irf2 downregulation was sufficient to recapitulate aspects of female peritoneal macrophage aging phenotypes, including increased glycolysis. Mechanistically, decreased Irf2 expression leads to decreased binding to its target genes, including Hk3, which encodes hexokinase (the rate-limiting enzyme of glycolysis). Our findings support the notion that aging leads to female-specific remodeling of mouse peritoneal macrophages through hormone-dependent and -independent mechanisms.

immunology↗

Synthetic Rewiring of Virus-Like Particles via Circular Permutation Enables Modular Peptide Display and Protein Encapsulation

Virus-like particles (VLPs) are self-assembling nanoparticles derived from viruses with potential as scaffolds for myriad applications. They are also excellent testbeds for engineering protein superstructures. Engineers often employ techniques such as amino acid substitutions and insertions/deletions. Yet evolution also utilizes circular permutation, a powerful natural strategy that has not been fully explored in engineering self-assembling protein nanoparticles. Here, we demonstrate this technique using the MS2 VLP as a model self-assembling, proteinaceous nanoparticle. We constructed, for the first time, a comprehensive circular permutation library of the fused MS2 coat protein dimer construct. The strategy revealed new terminal locations, validated via cryo-electron microscopy, that enabled C-terminal peptide tagging and led to a stable protein encapsulation strategy via covalent bonding - a feature the native coat protein does not permit. Our systematic study demonstrates the power of circular permutation for engineering new features as well as quantitatively and systematically exploring VLP structural determinants.

synthetic biology↗

An ultrasensitive and modular platform to detect Siglec ligands and control immune cell function

Siglecs are immunomodulatory receptors that regulate immune cell function. A fundamental challenge in studying Siglec-ligand interactions is the low affinity of Siglecs for their ligands. Inspired by how nature uses multivalency, we developed Siglec-liposomes as a highly multivalent and versatile platform for detecting Siglec glycan ligands in which recombinant Siglecs were conjugated to liposomes using the SpyCatcher-SpyTag system. Siglec-liposomes offer tunable multivalency and a modular assembly, enabling presentation of different Siglecs on the same liposome. Using Siglec-liposomes, we profiled Siglec ligands on human leukocytes, revealing new insights into Siglec ligands. Moreover, Siglec-liposomes are in vivo compatible, where we demonstrated that Siglec-7-liposomes bind to the brain vasculature in a mucin-dependent manner. Given the abundance of Siglec ligands on T cells, we investigated whether Siglec-liposomes modulate T cell function and find that Siglec-7-liposomes increase T cell proliferation in a ST3Gal1-dependent and CD43-independent manner. Taken together, Siglec-liposomes are a versatile and sensitive tool for detecting Siglec ligands and immunomodulation.

biochemistry↗

Reproducibility and Accuracy of Nanopore-Based Methylome Profiling of Streptococcus dysgalactiae subspecies equisimilis Strains from Cancer Patients

BackgroundDNA methylation influences bacterial gene regulation, virulence, and restriction-modification (RM) systems. Advances by Oxford Nanopore Technologies (ONT) now enable direct methylome profiling from nanopore sequencing using the Dorado basecaller. However, the comparative performance of ONT-only versus hybrid-assembly reference-based methylation calling, particularly regarding genomic DNA quality and inter-operator variability, remains understudied. MethodsSix operators independently prepared fifteen sequencing libraries each for nanopore (MinION R10.4.1 flow cells, Mk1D) and Illumina MiniSeq platforms for two Streptococcus dysgalactiae subsp. equisimilis strains (UT9728, 12 replicates; UT10237, 3 replicates). MicrobeMod v1.0.3 was used to identify methylation and motif profiles using Illumina-corrected hybrid reference assemblies (HRAs) and ONT-only reference assemblies (ORAs). Reproducibility and accuracy were compared using a custom genome annotation feature-enabled modular analysis that mapped and counted methylation site calls to CDS, rRNA and tRNA coordinates. ResultsStrain UT9728 predominantly exhibited N6-methyladenine (6mA) at GATC motifs, whereas strain UT10237 displayed dual methylation patterns: C5-methylcytosine (5mC) at CCWGG motifs and 6mA at GAGNNNNNTAA motifs. Both strains contained Type I and Type II RM systems; UT10237 uniquely harbored a Type IIG RM system with combined restriction and methylation activities. Motif identification concordance using HRAs and ORAs exceeded 99.9%. Reproducibility for methylation calls was high across independent replicates for both HRA (Pearsons r >0.989) and ORA (Pearsons r >0.993) methylation calls in GATC and CCWGG motifs but lower in the GAGNNNNNTAA motif (Pearsons r (HRA) = 0.80; r (ORA) = 0.78). ORA-based methylation site calls for all motifs showed excellent precision and recall compared to HRA-based calls (F1-score >99.999%). ConclusionOur findings support the accuracy, robustness, and utility of ONT-only data based methylome profiling for bacterial epigenetic characterization. Our analytical framework facilitates detailed evaluations of reproducibility and accuracy. Data Summary and AvailabilityO_LIUnprocessed_data_files: DOI: 10.5281/zenodo.15555625 O_LIRaw paired-end FastQ Files (Illumina). C_LIO_LIRaw FastQ Files (ONT; unmodified basecalls). C_LIO_LIRaw uBAM Files (ONT; 6mA_5MC_modified_basecalls). C_LI C_LIO_LIGenome_assemblies_and_annotation_files: DOI: 10.5281/zenodo.15558488 O_LIGenome_Assemblies reconstucted with ONT reads and polished with Illumina Reads (Hybrid assemblies);(strain_name_ _Hyb.gbk) C_LIO_LIGenome_Assemblies reconstructed with ONT reads and polished with ONT reads (ONT-only assemblies); (strain_name_ _ONT.fasta) C_LIO_LIGenBank flatfiles from Hybrid assemblies; (strain_name_ _Hyb.gbk) C_LIO_LIGenbank flatfiles from ONT-only assemblies. (strain_name_ _ONT.gbk) C_LI C_LIO_LIData_Tables and Python_code for modular analysis: DOI: doi.org/10.5281/zenodo.15579791 O_LI9728_10237_ORA+HRA_all_reps_microbemod_output.zip C_LIO_LIMethylation calls mapped to parsed genbank features & feature count matrix files. - [Formula] 9728_HRA_reproducibility_analysis_tables.zip - [Formula] 9728_ORA_reproducibility_analysis_tables.zip - [Formula] 10237_HRA_5mC_6mA_reproducibility_analysis_tables.zip - [Formula] 10237_ORA_reproducibility_analysis_tables.zip C_LIO_LIPython code for annotation feature-based modular analysis - [Formula] methylation_feature_hash_assert_FILTER_9728.py - [Formula] methylation_feature_hash_NOFILTER_9728.py - [Formula] methylation_feature_hash_motif_10237.py - [Formula] hyb_vs_ont_per_replicate_comparison.py - [Formula] hyb_vs_ont_combined_plot.py C_LI C_LIO_LIGenome Assembly_Code Availibility: https://github.com/TSchababerle/Bacterial-Methylation O_LIBash script for automated Hybrid Genome Assembly C_LIO_LIBash Script for automated ONT-Only Assembly C_LI C_LI Impact StatementThis study provides a focused proof-of-principle demonstrating the robustness and reproducibility of Oxford Nanopore Technologies (ONT) sequencing-based methylome profiling without short-read correction. Using independent replicates prepared by multiple operators, we show that nanopore-only methods yield consistent, accurate methylation profiles concordant with short-read corrected ONT reads. This highlights the potential of ONT-only sequencing as a broadly accessible, reliable approach for rapid bacterial epigenomic characterization across diverse clinical contexts.

genomics↗

Deficiencies in the Fanconi Anemia or the Homologous Recombination Pathway enhance the antitumor effects of the novel hypoxia-activated prodrug CP-506

The novel hypoxia-activated prodrug CP-506 has been shown to selectively target hypoxic tumor cells, which are associated with disease progression and resistance to conventional anti-cancer therapies. Given the alkylating effector metabolites, we hypothesize that defects in interstrand crosslink (ICL) and double strand break (DSB) DNA repair may serve as a predictive biomarker of sensitivity to CP-506. Here, we evaluated the role of DNA damage repair pathways in the antitumor response to CP-506. Isogenic cancer cell lines proficient or deficient in the Fanconi Anemia (FA), homologous recombination (HR), or non-homologous end joining (NHEJ) pathway were cultured as 2D monolayers and 3D spheroids. Cell viability, clonogenic cell survival, and spheroid growth inhibition were assessed following CP-506 exposure. Mice bearing subcutaneous isogenic xenografts received CP-506 (600 mg/kg; QD5) or vehicle treatment upon reaching a tumor starting volume (SV) of 244.9 {+/-} 72.0 mm3. Treatment response was quantified as time to reach 4xSV (T4xSV) and respective enhancement ratios (ER), defined as T4xSVCP-506/T4xSVvehicle. DNA damage and repair capacity were evaluated by {gamma}H2AX and alkaline comet assays. In vitro, cell lines deficient in FA or HR, but not NHEJ, showed enhanced sensitivity to CP-506 compared to parental cells in viability and clonogenic assays. This was confirmed in spheroid growth inhibition studies. In vivo, the antitumor response to CP-506 was more pronounced (P<0.0001) in LNCaP AR FANCA-/- (ER 4.0{+/-}1.1) and LNCaP AR FANCD2-/- (ER 3.4{+/-}0.8) xenografts compared to parental LNCaP AR (ER 1.5{+/-}0.5) xenografts. CP-506 treatment of DLD-1 BRCA2-/- (2.9{+/-}0.7; P<0.0001) xenografts resulted in significantly enhanced ER compared to parental (1.3{+/-}0.2) xenografts. Similar results were obtained in HCT116 BRCA2-/- (ER 4.0{+/-}0.6; P<0.0001) versus parental (ER 1.7{+/-}0.6) xenografts. In contrast, the ER of HCT116 DNA-PKcs-/- (1.4{+/-}0.3; P=0.18) xenografts was not different from HCT116 parental xenografts. Under anoxic conditions, CP-506 caused elevated {gamma}H2AX foci counts in FANCA-(2.0-fold increase at 48 hours) and FANCD2-deficient cells (1.4-fold increase at 72 hours) compared to LNCaP AR parental cells (P<0.0001). Similarly, {gamma}H2AX expression was increased in DLD-1 BRCA2-/- cells, but not in HCT116 BRCA2-/-cells, compared to their respective parental cells. In xenografts, FA- and HR-deficiency caused elevated {gamma}H2AX expression compared to respective parental tumors (1.6-9.3-fold increase). HCT116 DNA-PKcs-/- cells and xenografts displayed reduced {gamma}H2AX expression compared to their parental counterpart, with an 0.5-fold reduction. The comet assay confirmed CP-506-induced ICLs and DNA strand breaks but was unable to explain the differential therapeutic responses of CP-506 among isogenic tumor cells. Deficiencies within FA or HR, but not NHEJ, enhanced the antitumor effects of CP-506 through a mechanism consistent with the concept of synthetic lethality. Therefore, both DNA repair status and the presence of tumor hypoxia represent key biomarkers for patient stratification in clinical trials of CP-506.

cancer biology↗

A 3D Modeling Framework for Quantifying Variation in Soybean Root Structure Architecture

Root system architecture (RSA) underpins plant access to water and nutrients, making its characterization critical for improving crop performance in environments with limited soil fertility. However, current methods for quantifying root features face several challenges. They may rely on 2D images that suffer from occlusion, use expensive sensing technologies like X-ray computed tomography, or depend on 3D modeling approaches with assumptions about branching that make them difficult to generalize. To address these challenges, we introduce an open-source Python framework for quantifying RSA samples from 3D point clouds generated from low-cost photogrammetry. Critically, this method incorporates no assumptions about taxon-specific branching orientation, making it both well-suited for modeling naturally grown annual dicots such as soybean and generalizable across species. Using field-grown soybean as a test case, we demonstrate the utility of this framework to extract biologically meaningful 3D features of divergent root systems sampled across developmental stages and soil environments, and enable new analyses not possible with 2D approaches, such as modeling metabolic scaling relationships. Results indicate that, in our soybean samples, while certain individual features like taproot tortuosity are potentially influenced by the soil environment, and while roots in sandy loam exhibited greater feature plasticity, fundamental scaling properties remain consistent. By combining low-cost photogrammetry with 3D reconstruction of root systems from point clouds, this approach provides the plant science community with new opportunities for more comprehensive root studies.

plant biology↗

H2O2-induced astrocytic collagen triggers neuronal death via fucosylation-dependent glial barrier formation upon ischemic stroke

The cascade of molecular and cellular events leading to neuronal death after a focal ischemic stroke remains enigmatic. Although astrocytes form glial barriers that may protect surrounding tissue, how barriers develop and contribute to neuronal death is unclear. Here, we show that H2O2 induces astrocytic type I collagen (COL1)-production via miR-29-mediated post-transcriptional and fucosylation-dependent post-translational regulations, leading to integrin activation and neuronal death. In photothrombosis (PT)-induced cortical stroke model, PT triggered H2O2-surge, astrogliosis, glial barrier formation, COL1 expression, fibrotic scarring, altered N-glycosylation, neuronal loss, and neurological deficits. Remarkably, these effects were reversed by astrocyte-specific COL1 or FUT8 gene-silencing or treatment with KDS12025, an H2O2-decomposing peroxidase enhancer. KDS12025s neuroprotective effects were also recapitulated in non-human primate stroke model. These findings delineate a previously unrecognized astrocyte-driven mechanism in which oxidative stress induces COL1 production, promoting neuronal death, and position H2O2 and astrocytic COL1 and FUT8 as promising therapeutic targets for ischemic stroke.

neuroscience↗

Divergence of root system traits in soybean between breeding and diversity lines

Roots are critical for supporting basic plant functions such as anchoring in various substrates, uptake of water and nutrients, and hosting symbiotic relationships. In crops, indirect changes to root system architecture (RSA) have occurred largely as a result of selection for yield or other related aboveground traits. In cultivated soybean (Glycine max), evidence of changes to RSA resulting from breeding for crop performance has been inconsistent, with some studies supporting an overall decrease in performance-related trait values, such as root length and density, and other work showing the opposite. The current study sets out to ask whether there is any systematic differentiation in RSA between a set of elite breeding lines (n=8) of soybean developed for the Midwest United States and a group of biogeographically diverse landraces from the USDA Soybean Germplasm Collection (n=16. Groups are compared across three distinct developmental stages (V2-V6, V7-R2, R3-R7) and two contrasting soil environments. In total, 432 root systems were phenotyped for 12 structural traits derived from 2D images along with root and shoot biomass. A new 3D root modeling approach leveraging photogrammetry-derived pointclouds is additionally tested on a subset of 30 contrasting root systems. Results indicate that the diversity lines had smaller root systems overall but greater phenotypic plasticity in response to soil environment as compared to breeding lines. Additionally, the study finds evidence for trade-offs between above-ground and below-ground trait plasticity. Core ideasO_LIPrevious work suggests crop root system architecture (RSA) has changed as a result of indirect selection C_LIO_LIThis study compares RSA in elite breeding lines with that of diverse landraces in cultivated soybean C_LIO_LIA total of 432 root systems are analyzed across 24 genotypes, two soil environments and three developmental stages C_LIO_LIFindings show diversity lines have smaller root systems but greater plasticity in response to soil environment C_LI

plant biology↗

Functional connectivity reveals increased network segregation and sensorimotor processing during working memory in adolescents with Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is a rare, monogenic condition associated with impairments in working memory processing. However, it is unknown to what extent these impairments are explained by disrupted connectivity and state transitions of the functional brain networks. This study characterised task-state functional connectivity (FC) and network controllability during working memory in NF1 and investigated whether altered controllability distinguished NF1 from neurotypical controls and related to individual differences in working memory performance. We analysed functional MRI data from 53 NF1 adolescents and 36 age-matched neurotypical controls performing a verbal N-back task. Compared to controls, NF1 participants showed reduced FC within frontoparietal network (particularly between the left prefrontal cortex and left intraparietal sulcus), reduced FC between default and limbic networks, and increased FC between control and somatomotor regions. Network controllability analysis revealed increased average controllability but reduced modal controllability and activation energy in prefrontal, parietal, temporal and retrosplenial regions in NF1, indicating that in NF1 these regions have enhanced capacity to drive the network toward easy-to-reach states and are readily activated within the current network organisation. The opposite pattern of reduced average controllability but increased modal controllability and activation energy were observed in somatosensory, auditory, extrastriate and temporal-parietal regions, suggesting enhanced capacity of these regions to drive the network towards difficult-to-reach states. These changes accurately predicted NF1 status, with an area under the ROC curve exceeding 80% across all controllability models. Furthermore, average controllability accurately predicted working memory performance in the NF1 group, generalising to out-of-sample data. In particular, left and right lateral ventral prefrontal cortex, left superior parietal lobule, left intraparietal sulcus consistently emerged as predictors of working memory performance across all measures. By demonstrating that altered regional network controllability in NF1 predicts working memory performance, this study provides a novel mechanistic account of the functional network alterations underlying cognitive difficulties in NF1 and establishes a framework for evaluating future therapeutic interventions through their effects on functional brain network control.

neuroscience↗

The Drosophila SPECC1L homolog, Split Discs, co-localizes with non-muscle myosin II and regulates focal adhesion dynamics.

Allelic variations of Sperm antigen with calponin homology and Coiled-Coil domains 1 Like (SPECC1L) have been associated with a spectrum of cranial-facial pathologies including Teebi hypertelorism and Opitz G/BBB syndrome which manifest as clefting of the palate, wide-eyes, and incomplete closure of the esophagus among others. These pathologies may be indicative of improper cranial neural crest cell (CNCC) delamination and migration. SPECC1L is hypothesized to be an actin-microtubule cross-linking protein as it co-localizes with both microtubules and actin in tissue culture cells. Further, it has been shown to immunoprecipitate with a protein phosphatase complex-1{beta} (PP1{beta}) member, MYPT1, as well as being involved in the PI3K-AKT signaling axis. In this study we sought to investigate the SPECC1L Drosophila homolog Spdi and despite sharing close homology with its mammalian counterpart we found that Spdi is associated with both non-muscle myosin-II and actin. RNAi depletion of Spdi led to an increase in focal adhesion dynamics and when we introduced conserved point mutations to Spdi that are analogous to those associated with human disease we observed a further increase in focal adhesion dynamics above that of depletion alone. Collectively, our findings suggest that Spdi is a non-muscle myosin II (NMII) binding protein that likely affects focal adhesion dynamics through this association. Our results also suggest that some of the pathologies associated with allelic variants of SPECC1L may be the result of aberrant cell-matrix adhesion.

cell biology↗

The Mismatch Negativity compared: EEG, SQUID-MEG and novel 4Helium-OPMs

Magneto-encephalography (MEG) provides a higher spatial resolution than electro-encephalography (EEG) to measure human auditory responses. However, conventional cryogenic MEG systems (SQUID-MEG) suffer from severe technological restrictions limiting, for instance, routine clinical use. Fortunately, a new generation of MEG sensors, optically pumped magnetometers (OPMs), have been developed to bridge the gap, combining the wearability of EEG with the benefits of MEG signal acquisition. We aim to assess their potential for studying auditory mismatch processing. The auditory Mismatch Negativity (MMN) is a well-characterized evoked component observable using a passive oddball paradigm with two-tone sound sequences. It has been extensively described using both EEG and MEG and is part of many EEG-based clinical applications, such as the assessment of patients with disorders of consciousness. MMN is therefore a relevant candidate to evaluate OPM performance. We use recently developed Helium-OPMs, which are high dynamic range MEG sensors that operate at room temperature. We compare their performance with cryogenic SQUID-MEG and EEG in a passive frequency oddball paradigm. Results show a significant MMN across subjects in all modalities as well as a high temporal similarity between modalities. Signal-to-noise ratios were also similar, and detection of significant individual MMN (within-subjects) using the OPM system was equal or better than EEG. Given that the OPM system tested here is a prototype comprised of only five sensors, these results are a promising step towards wearable MEG that combines the advantages of MEG and EEG.

neuroscience↗

Transcranial focused ultrasound stimulation of the anterior temporal lobe enhances semantic memory by modulating brain morphology, neurochemistry and neural dynamics

AbstractsUnderstanding neural functioning and plasticity of the brain is a fundamental goal of neuroscience. The ventromedial anterior temporal lobe (ATL) has been suggested as the centre-point of a core transmodal hub for semantic memory, playing a crucial role in the representation of coherent conceptual knowledge. However, non-invasive direct modulation of the ventromedial ATL has remained challenging. Transcranial ultrasound stimulation (TUS) is an emerging neuromodulatory technique that delivers acoustic energy with high spatial precision, making it uniquely suited for targeting deep brain structures non-invasively. In this study, we investigated whether theta-burst TUS (tbTUS) to the ventromedial ATL could enhance semantic memory performance in the adult brain. Using a multimodal neuroimaging approach-- magnetic resonance spectroscopy (MRS), functional MRI (fMRI), and voxel-based morphometry (VBM)--we assessed tbTUS-induced changes in neurochemical concentrations, functional network connectivity, structural plasticity, and semantic memory performance. Compared to control stimulation (ventricle), tbTUS at the ventromedial ATL significantly improved semantic task performance in healthy individuals. MRS analysis revealed that tbTUS decreased GABA and increased Glx levels, reflecting shifts in excitation-inhibition balance. Additionally, tbTUS increased neurometabolites in the ATL, including NAA, creatine and choline, suggesting enhanced neuronal function and metabolism. fMRI analysis demonstrated that tbTUS reduced task-induced regional activity in the ATL and functionally connected semantic regions, while also enhancing intrinsic and effective connectivity across the semantic network. Structural analysis revealed increased grey matter volume in the ATL following tbTUS compared to control stimulation. These findings provide the first convergent evidence that tbTUS can modulate neurochemistry, functional dynamics, and brain morphology to enhance semantic memory function. Our results highlight TUS as a powerful neuromodulatory tool with potential applications in cognitive enhancement and neurorehabilitation, offering a promising intervention for dementia and neurodegenerative disorders.

neuroscience↗

DdiA, an XRE family transcriptional regulator, regulates a LexA-independent DNA damage response in Myxococcus xanthus

Repair of DNA damage is essential for genome integrity. DNA damage elicits a DNA damage response (DDR) that includes error-free and error-prone, i.e. mutagenic, repair. The SOS response is a widely conserved system in bacteria that regulates the DDR and depends on the recombinase RecA and the transcriptional repressor LexA. However, RecA/LexA-independent DDRs have been identified in several bacterial species. Here, using a whole-cell, label-free quantitative proteomics approach, we map the proteomic response in Myxococcus xanthus to mitomycin C treatment and the lack of LexA. In doing so, we confirm a LexA-independent DDR in M. xanthus. Using a candidate approach, we identify DdiA, a transcriptional regulator of the XRE family, and demonstrate that it regulates a subset of the LexA-independent DDR genes. ddiA is expressed heterogeneously in a subpopulation of cells in the absence of exogenous genotoxic stress and reversibly induced population-wide in response to such stress. DdiA, indirectly or directly, activates the expression of dnaE2, which encodes the DnaE2 error-prone DNA polymerase, and inhibits the expression of recX, which encodes RecX, a negative regulator of RecA. Accordingly, the {Delta}ddiA mutant has a lower mutation frequency than the wild-type but also a fitness defect, suggesting that DdiA mediates a trade-off between fitness and mutagenesis. We speculate that the DdiA-dependent response is tailored to counter replication stress, thereby preventing the induction of the complete RecA/LexA-dependent DDR in the absence of exogenous genotoxic stress. ImportanceDNA damage repair is essential for genome integrity and depends on the DNA damage response (DDR). While the RecA/LexA-dependent SOS response is widely conserved in bacteria, there are also RecA/LexA-independent DDRs. Here, we identify the DNA damage-induced transcriptional regulator DdiA in Myxococcus xanthus and demonstrate that it regulates part of the RecA/LexA-independent DDR. DdiA activates the expression of dnaE2, which encodes the DnaE2 error-prone DNA polymerase, and inhibits the expression of recX, which encodes RecX, a negative regulator of RecA. Because the {Delta}ddiA mutant has a lower mutation frequency than the wild-type but also a fitness defect, we suggest that DdiA mediates a trade-off between fitness and mutagenesis and that the DdiA-dependent DDR is specifically tailored to counter replication stress.

microbiology↗

An antisense oligomer conjugate with unpredicted bactericidal activity against Fusobacterium nucleatum

Fusobacteria are commensal members of the oral microbiome that can spread from their primary niche and colonize distal sites in the human body. Their enrichment in colorectal and breast cancer tissue has been associated with tumor growth, metastasis, and chemotherapeutic resistance. The use of non-selective antibiotics to remove fusobacteria impairs tumor progression, but prolonged application risks side effects such as gastrointestinal problems and dysbiosis. Species-specific antisense antibiotics based on peptide nucleic acid (PNA) have shown efficacy in many Gram-negative species, suggesting that antisense PNAs may also enable a tailored depletion of fusobacteria. Here, we have investigated the antibacterial potential of cell-penetrating peptide (CPP)-PNA conjugates targeting the mRNA of putative essential genes in Fusobacterium nucleatum. Unexpectedly, we observed no growth inhibition with any of the target-specific PNAs, but identified a non-targeting control CPP-PNA (FUS79, (RXR)4XB-GACATAATTGT) as a potent growth inhibitor of F. nucleatum. Our data suggest that the CPP and specific sequence features of FUS79 are responsible for its activity, rather than an antisense effect. Interestingly, FUS79 also inhibits the growth of five additional fusobacterial strains but not of F. nucleatum ssp. vincentii (FNV). RNA-seq analysis indicates that FUS79 induces a membrane stress response in a vulnerable F. nucleatum strain but not in FNV. Collectively, our attempt at developing antisense antibiotics for fusobacteria discovers a potent growth inhibitor, whose bactericidal effect appears independent of target-specific mRNA inhibition. IMPORTANCEEnrichment of F. nucleatum at cancer sites is associated with increased tumor growth and metastasis. Antibiotic treatment to remove the bacteria was shown to change the course of cancer progression. Here we explore first steps to establish peptide nucleic acids (PNAs) as specific antisense antibiotics, thereby laying the foundation for further development of antisense technology in fusobacteria. While the CPP-PNA FUS79 was initially designed as a control, we observed that the compound was bactericidal for specific fusobacterial strains. Our results suggest that FUS79 might be able to selectively deplete fusobacterial strains from bacterial communities, offering a new perspective on fusobacterial removal at the tumor site.

microbiology↗