Biology subjects

Voigt, A.

Publications and source records attributed to Voigt, A..

At least 19 recordsLinked to original sources

bioRxiv2026

Infection and sensitization reveal stimulus-specific immune remodeling in aged skin

Aging is associated with progressive declines in skin barrier integrity and immune protection, contributing to increased susceptibility to bacterial and viral skin infections in older adults. However, how aged skin senses and responds to infection or barrier disruption remains poorly defined. Here, we characterized the age-associated cutaneous immune response to epicutaneous Staphylococcus (S.) aureus infection and ovalbumin-induced sensitization in mouse models. Bulk RNA-seq of infected tissue showed that transcriptional variation was primarily driven by infection, not age, suggesting that aged skin retains a broadly inducible response to microbial challenge. In contrast, microneedle patch (MNP) sampling of skin interstitial fluid, which provides cellular resolution, revealed age-dependent differences in local immune dynamics after S. aureus infection, including altered magnitude and kinetics of cellular recruitment, such as an attenuated cutaneous T cell response in older mice. MNP profiling further showed that ovalbumin sensitization elicited a localized immune program distinct from the S. aureus response, which was incompletely reflected in systemic measurements. Together, these data demonstrate that aging does not uniformly impair cutaneous immunity but instead is a context-dependent remodeling of local tissue immune dynamics.

microbiology↗

bioRxiv2026

Species and strain diversity in Staphylococcus drive divergent host responses in human skin

The skin microbiome regulates key skin processes, yet the functional diversity of a dominant genus, Staphylococcus, remains poorly resolved at the strain level for multiple species across its pathogenic and commensal continuum. It is likely that Staphylococcus effects on skin are diverse at these finest taxonomic resolutions, but current skin models lack the physiological relevance and scalability needed to profile this diversity. Using an organotypic 3D human skin model (reconstructed human epidermis, RHE), we profiled skin responses to 187 Staphylococcus strains across seven dominant species. Canonically pathogenic species (e.g., S. aureus) induced broad inflammatory responses, whereas prototypical commensal species (e.g., S. hominis) elicited more nuanced effects on innate immune and skin barrier responses. Strikingly, S. epidermidis displayed pronounced strain-level heterogeneity, with subsets inducing either commensal or pathogen-like responses despite lacking canonical virulence factors, suggesting pleiotropic effects. Comparative genomics, dual-transcriptomics, untargeted metabolomics, and growth phenotyping revealed species- and strain-specific traits underlying these differential effects on RHE, including the presence of select cell surface proteins and differential arginine metabolism. Together, our study provides the first high-throughput, species- and strain-resolved analysis of skin-Staphylococcus interactions, offering mechanistic insights and a platform for microbiome-based strategies to modulate skin inflammation and diseases. One-line summaryHigh-throughput profiling of Staphylococcus in a human skin model shows that species- and strain-level diversity underlies a continuum of host barrier and immune responses.

microbiology↗

bioRxiv2025

Discover Potential New Epitopes through Post Translational Modification in Sjogrens Disease

Sjogrens syndrome (SjD) is a chronic autoimmune disorder in which the immune system attacks the glands that produce tears and saliva, leading to symptoms such as dry eyes and dry mouth. If left untreated, SjD can also cause inflammation and damage to other parts of the body, including the skin, lungs, kidneys, and nervous system, and increase the risk of developing lymphoma. The human leukocyte antigen (HLA) class II molecule HLA-DR3 is strongly associated with SjD. To investigate how post-translational modifications (PTMs) influence the presentation of SjD-associated autoantigens by HLA-DR3, we employed a computational framework to analyze the binding of PTM-mimic peptides to HLA-DR3. Our analysis revealed that PTM-mimic substitutions at canonical anchor positions rarely improved predicted binding affinity using the Stabilized Matrix Method, with most modifications resulting in reduced affinity. However, a comprehensive analysis of full-length SjD-associated autoantigen sequences (Ro60, Ro52, La) identified discrete regions with high densities of PTM-eligible anchor sites, specifically, the Ro60 HEAT solenoid, Ro52 RING/B-box/PRY-SPRY modules, and the La motif-RRM1 region, suggesting that PTMs may alter epitope presentation in a sequence-dependent manner. Experimental validation of selected PTM-mimic peptides demonstrated enhanced T cell responses, which were associated with increased binding affinity to HLA-DR3. Structural modeling of a representative complex revealed that PTM-mimic peptides adopt a slightly shifted backbone orientation and altered side-chain positioning, leading to a larger peptide-DR3 interaction interface. These findings provide new insights into the role of PTMs in shaping the immunogenicity of SjD-associated autoantigens and highlight the potential for PTM-mimic peptides to modulate T cell responses in SjD.

immunology↗

bioRxiv2025

Calbindin-containing CA1 pyramidal cells support cognitive flexibility in spatial task in mice

The hippocampus, and particularly the dorsal CA1, is essential for spatial memory consolidation through sharp-wave ripple events (SWRs) that enable the transfer of information to cortical areas. Within the dorsal CA1, distinct pyramidal cell sub-populations of the deep and superficial layer may play distinct roles in the processing and updating of spatial information. Using a Cre-dependent mouseline, we were able to precisely target the superficial, Calbindin (CALB1+) PCs of the CA1. This allowed us to gain a deeper understanding of the connectivity of CALB1+ CA1 PCs to their SWR-propagating excitatory output partners within the Subiculum (SUB), the burst-firing SUB PCs and their functional relevance in spatial memory consolidation and recall. Retrograde rabies tracing revealed heterogeneous innervation of the VGlut2+ bursting PCs by both CA1 PC sub-layers, and showed that the majority of presynaptic inputs are located in the superficial CA1 PC layer. We were able to observe that this anatomically confirmed connection between CALB1+ CA1 PCs and both SUB PC subtypes is able to induce spiking more reliably in burst- than regular-firing SUB PCs. CNO-induced inhibition in a Barnes Maze task revealed that the experimental group showed reduced cognitive flexibility and were slower to adapt to re-location of the goal when CALB1+ CA1 PCs were inhibited during the recall (test), while both groups behaved similarly when consolidation was manipulated (training). Inhibition did not impact overall learning, strategy development or locomotor control. This suggests that CALB1+ CA1 PCs preferentially connect to bursting SUB PCs, and support cognitive flexibility needed to adapt to a changing environment, adding further proof to the functional relevance of laminar segregation of the CA1 and the hippocampus in spatial memory processes.

neuroscience↗

bioRxiv2025

Contextual modulation and blunted defensive responses to predators in head-fixed and freely moving mice

Behavioral responses to threat -- such as fleeing, freezing, or fighting--can be innate, learned, and strongly shaped by context or competing goals. Here, we asked whether exposure to an ecologically relevant predator obligatorily elicits canonical defensive behaviors across behavioral contexts. We examined predator responses in mice across four experimental conditions: one novel head-fixed reward-driven foraging task and three established paradigms in freely moving animals. In the head-fixed condition, water-deprived mice were trained to walk on a treadmill controlling a virtual environment and water reward delivery and were subsequently exposed to a live rat positioned above the lick spout. Despite the presence of the predator, most mice (5 of 7) maintained foraging performance at baseline levels. However, individual mice exhibited significant, coordinated changes in running speed, pupil diameter, eye movements, and posture, indicating engagement with the threat. To assess how context influences predator responses, we exposed 36 naive, freely moving mice to fear-inducing stimuli, including looming visual cues, rat odor, and a live rat. Even under these conditions, defensive behaviors were variable: only a subset of mice displayed avoidance or escape, and when presented with a freely moving rat, approximately half of the mice avoided the predator. Together, these findings show that predator threat does not elicit a uniform or obligatory defensive repertoire in mice. Instead, defensive responses are expressed flexibly, and are shaped by environmental constraints, task demands, and individual variability. These results challenge the assumption that innate fear behaviors are automatically triggered by predator encounters. Graphical AbstractUsing a head-fixed, reward-based foraging task and complementary freely moving paradigms, we show that mouse responses to predator-related stimuli are variable and context dependent, with limited expression of canonical defensive behaviors such as freezing or flight. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/658679v3_ufig1.gif" ALT="Figure 1"> View larger version (65K): org.highwire.dtl.DTLVardef@a05a31org.highwire.dtl.DTLVardef@1815084org.highwire.dtl.DTLVardef@cd3a11org.highwire.dtl.DTLVardef@19f5d95_HPS_FORMAT_FIGEXP M_FIG C_FIG

animal behavior and cognition↗

bioRxiv2025

Modeling AP2M1 Developmental and Epileptic Encephalopathy in Drosophila

Genetic defects in AP2M1, which encodes the -subunit of the adaptor protein complex 2 (AP-2) essential for clathrin-mediated endocytosis (CME), cause a rare form of developmental and epileptic encephalopathy (DEE). In this study, we modeled AP2M1-DEE in Drosophila melanogaster to gain deeper insights into the underlying disease mechanisms. Pan-neuronal knock-down of the Drosophila AP2M1 ortholog, AP-2{micro}, resulted in a consistent heat-sensitive paralysis phenotype and altered morphology in class IV dendritic arborization (c4da) neurons. Unexpectedly, affected flies were resistant to antiseizure medications and exhibited increased resistance to electrically induced seizures. A CRISPR-engineered fly line carrying the recurrent human disease variant p.Arg170Trp displayed a milder seizure resistance phenotype. While these findings contrast with the human phenotype, they align with previous studies on other CME-related genes in Drosophila. Our results suggest that hyperexcitability and seizures in AP2M1-DEE may stem from broader defects in neuronal development rather than direct synaptic dysfunction.

neuroscience↗

bioRxiv2025

Quantifying the shape of cells - from Minkowski tensors to p-atic order

P-atic liquid crystal theories offer new perspectives on how cells self-organize and respond to mechanical cues. Understanding and quantifying the underlying orientational orders is therefore essential for unraveling the physical mechanisms that govern tissue dynamics. Due to the deformability of cells this requires quantifying their shape. We introduce rigorous mathematical tools and a reliable framework for such shape analysis. Applying this to segmented cells in MDCK monolayers and computational approaches for active vertex models and multiphase field models allows to demonstrate independence of shape measures and the presence of various p-atic orders at the same time. This challenges previous findings and opens new pathways for understanding the role of orientational symmetries and p-atic liquid crystal theories in tissue mechanics and development.

biophysics↗

bioRxiv2024

USP37 prevents premature disassembly of stressed replisomes by TRAIP

The E3 ubiquitin ligase TRAIP associates with the replisome and helps this molecular machine deal with replication stress. Thus, TRAIP promotes DNA inter-strand crosslink repair by triggering the disassembly of CDC45-MCM2-7-GINS (CMG) helicases that have converged on these lesions. However, disassembly of single CMGs that have stalled temporarily would be deleterious, suggesting that TRAIP must be carefully regulated. Here, we demonstrate that human cells lacking the de-ubiquitylating enzyme USP37 are hypersensitive to topoisomerase poisons and other replication stress-inducing agents. We further show that TRAIP loss rescues the hypersensitivity of USP37 knockout cells to topoisomerase inhibitors. In Xenopus egg extracts depleted of USP37, TRAIP promotes premature CMG ubiquitylation and disassembly when converging replisomes stall. Finally, guided by AlphaFold-Multimer, we discovered that binding to CDC45 mediates USP37s response to topological stress. In conclusion, we propose that USP37 protects genome stability by preventing TRAIP-dependent CMG unloading when replication stress impedes timely termination.

molecular biology↗

bioRxiv2024

Emergence of bluetongue virus serotype 3 in western Germany, October 2023, and ad-hoc monitoring in Culicoides biting midges

Bluetongue virus serotype 3 emerged in October 2023 in Germany, where Schmallenberg virus is enzootic. BTV-3 was detected in a pool of Culicoides biting midges at the same time as infections were reported from ruminants. Schmallenberg virus was frequently found in vector pools, reflecting the epidemiological situation. One sentence summary lineCoinciding with the emergence and low-level circulation of bluetongue virus serotype 3 in ruminants in Germany in October 2023, the virus was detected in a pool of Culicoides biting midges of the Obsoletus Group, while enzootic Schmallenberg virus was found in numerous midge pools.

microbiology↗

bioRxiv2023

Species- and strain-effects in interferon, innate immunity, and barrier transcriptional response of microbiome interactions of 3D respiratory epithelial cultures

The microbiome modulates the respiratory epitheliums immunomodulatory functions. To explore how the microbiomes biodiversity affects microbe-epithelial interactions, we screened 58 phylogenetically diverse microbes for their transcriptomic effect on tracheobronchial air-liquid interface cell (ALI) cultures. We found distinct species- and strain-level differences in host innate immunity, and epithelial barrier response. Strikingly, we found that host interferon, an antiviral immune response, was one of the most variable host processes, and this variability was not driven by microbial phylogenetic diversity, bioburden, nor by the microbes ability to stimulate other innate immunity pathways. Our study provides a foundation for understanding how the respiratory microbiomes biodiversity affects epithelial, and particularly, antiviral innate immunity.

microbiology↗

bioRxiv2023

Axis convergence in C. elegans embryos

Embryos develop in a surrounding that guides key aspects of their development. For example, the anteroposterior (AP) body axis is always aligned with the geometric long axis of the surrounding eggshell in fruit flies and worms. The mechanisms that ensure convergence of the AP axis with the long axis of the eggshell remain unresolved. We investigate axis convergence in early C. elegans development, where the nascent AP axis, when misaligned, actively re-aligns to converge with the long axis of the egg. Here, we identify two physical mechanisms that underlie axis convergence. First, bulk cytoplasmic flows, driven by actomyosin cortical flows, can directly reposition the AP axis. Second, active forces generated within the pseudocleavage furrow, a transient actomyosin structure similar to a contractile ring, can drive a mechanical re-orientation such that it becomes positioned perpendicular to the long axis of the egg. This in turn ensures AP axis convergence. Numerical simulations, together with experiments that either abolish the pseudocleavage furrow or change the shape of the egg, demonstrate that the pseudocleavage furrow-dependent mechanism is the key driver of axis convergence. We conclude that active force generation within the actomyosin cortical layer drives axis convergence in the early nematode.

biophysics↗

bioRxiv2022

Human TRMT2A methylates different components of the translation machinery and contributes to translation fidelity

Methyl-5-uridine (m5U) is one of the most abundant RNA modifications found in cytosolic tRNA. tRNA methyltransferase 2 homolog A (hTRMT2A) is the dedicated mammalian enzyme of m5U formation at tRNA position 54. However, its RNA binding specificity and functional role in the cell are not well understood. Here we dissected structural and sequence requirements for binding and methylation of its RNA targets. Specificity of tRNA modification by TRMT2A is achieved by a combination of modest binding preference and presence of a uridine in position 54 of tRNAs. Mutational analysis together with crosslinking experiments identified a large hTRMT2A-tRNA binding surface. Furthermore, complementing hTRMT2A interactome studies revealed that TRMT2A interacts with proteins involved in RNA biogenesis. Finally, we addressed the question of the importance of TRMT2A function by showing that its knockdown reduces translation fidelity. These findings extend the role of hTRMT2A beyond tRNA modification towards a role in translation.

biochemistry↗

bioRxiv2022

Branch point evolution controls species-specific alternative splicing and regulates long term potentiation

Regulation and functionality of species-specific alternative splicing has remained enigmatic to the present date. Calcium/calmodulin-dependent protein kinase II{beta} (CaMKII{beta}) is expressed in several splice variants and plays a key role in learning and memory. Here, we identify and characterize several primate-specific CAMK2B splice isoforms, which show altered kinetic properties and changes in substrate specificity. Furthermore, we demonstrate that primate-specific Camk2{beta} alternative splicing is achieved through branch point weakening during evolution. We show that reducing branch point and splice site strengths during evolution globally renders constitutive exons alternative, thus providing a paradigm for cis-directed species-specific alternative splicing regulation. Using CRISPR/Cas9 we introduced a weaker human branch point into the mouse genome, resulting in human-like CAMK2B splicing in the brain of mutant mice. We observe a strong impairment of long-term potentiation in CA3-CA1 synapses of mutant mice, thus connecting branch point-controlled, species-specific alternative splicing with a fundamental function in learning and memory.

molecular biology↗

bioRxiv2022

Analysis of pre-symptomatic Drosophila models for ALS and SMA reveals convergent impact on functional protein complexes linked to neuro-muscular degeneration

Spinal Muscular Atrophy (SMA) and Amyotrophic Lateral Sclerosis (ALS) share phenotypic and molecular commonalities, including the fact that they can be caused by mutations in ubiquitous proteins involved in RNA metabolism, namely SMN, TDP-43 and FUS. Although this suggests the existence of common disease mechanisms, there is currently no model to explain the resulting motor neuron dysfunction. In this work we generated a parallel set of Drosophila models for adult-onset RNAi and tagged neuronal expression of the fly orthologues of the three human proteins, named Smn, TBPH and Caz, respectively. We profiled nuclear and cytoplasmic bound mRNAs using a RIP-seq approach and characterized the transcriptome of the RNAi models by RNA-seq. To unravel the mechanisms underlying the common functional impact of these proteins on neuronal cells, we devised a computational approach based on the construction of a tissue-specific library of protein functional modules, selected by an overall impact score measuring the estimated extent of perturbation caused by each gene knockdown. Transcriptome analysis revealed that the three proteins do not bind to the same RNA molecules and that only a limited set of functionally unrelated transcripts is commonly affected by their knock-down. However, our integrative approach revealed they exert a concerted effect on protein functional modules, acting through distinct targets. Most strikingly, functional annotation revealed that these modules are involved in critical cellular pathways for motor neurons, including neuromuscular junction function. Furthermore, selected modules were found to be significantly enriched in orthologues of human neuronal disease genes. The results presented here show that SMA and ALS disease-associated genes linked to RNA metabolism functionally converge on neuronal protein complexes, providing a new hypothesis to explain the common motor neuron phenotype. The functional modules identified represent promising biomarkers and therapeutic targets, namely given their alteration in asymptomatic settings.

neuroscience↗

bioRxiv2021

Small-molecule modulators of TRMT2A decrease PolyQ aggregation and PolyQ-induced cell death

Polyglutamine (polyQ) diseases are characterized by an expansion of cytosine-adenine-guanine (CAG) trinucleotide repeats encoding for an uninterrupted prolonged polyQ tract. We previously identified TRMT2A as a strong modifier of polyQ-induced toxicity in an unbiased large-scale screen in Drosophila melanogaster. This work aimed at identifying and validating pharmacological TRMT2A inhibitors as treatment opportunities for polyQ diseases in humans. Computer-aided drug discovery was implemented to identify human TRMT2A inhibitors. Additionally, the crystal structure of one protein domain, the RNA recognition motif (RRM), was determined, and Biacore experiments with the RRM were performed. The identified molecules were validated for their potency to reduce polyQ aggregation and polyQ-induced cell death in human HEK293T cells and patient derived fibroblasts. Our work provides a first step towards pharmacological inhibition of this enzyme and indicates TRMT2A as a viable drug target for polyQ diseases.

molecular biology↗

bioRxiv2020

High-quality genome-scale metabolic model of Aurantiochytrium sp. T66

The long-chain,{omega} -3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are essential for humans and animals, including marine fish species. Presently, the primary source of these PUFAs is fish oils. As the global production of fish oils appears to be reaching its limits, alternative sources of high-quality{omega} -3 PUFAs is paramount to support the growing aquaculture industry. Thraustochytrids are a group of heterotrophic protists able to synthesize and accrue large amounts of essential{omega} -3 PUFAs, including EPA and DHA. Thus, the thraustochytrids are prime candidates to solve the increasing demand for{omega} -3 PUFAs using microbial cell factories. However, a systems-level understanding of their metabolic shift from cellular growth into lipid accumulation is, to a large extent, unclear. Here, we reconstructed a high-quality genome-scale metabolic model of the thraustochytrid Aurantiochytrium sp. T66 termed iVS1191. Through iterative rounds of model refinement and extensive manual curation, we significantly enhanced the metabolic scope and coverage of the reconstruction from that of previously published models, making considerable improvements with stoichiometric consistency, metabolic connectivity, and model annotations. We show that iVS1191 is highly consistent with experimental growth data, reproducing in vivo growth phenotypes as well as specific growth rates on minimal carbon media. The availability of iVS1191 provides a solid framework for further developing our understanding of T66s metabolic properties, as well as exploring metabolic engineering and process-optimization strategies in silico for increased{omega} -3 PUFA production.

systems biology↗

bioRxiv2020

A CRISPR-Cas9-engineered mouse model for GPI anchor deficiency mirrors human phenotype and shows hippocampal synaptic dysfunctions.

Pathogenic germline mutations in PIGV lead to glycosylphosphatidylinositol biosynthesis deficiency (GPIBD). Individuals with pathogenic biallelic mutations in genes of the glycosylphosphatidylinositol (GPI) anchor pathway exhibit cognitive impairments, motor delay, and often epilepsy. Thus far, the pathophysiology underlying the disease remains unclear, and suitable rodent models that mirror all symptoms observed in human patients have not been available. Therefore, we used CRISPR-Cas9 to introduce the most prevalent hypomorphic missense mutation in European patients, Pigv:c.1022C>A (p.A341E), at a site that is conserved in mice. Mirroring the human pathology, mutant Pigv341E mice exhibited deficits in motor coordination, cognitive impairments, and alterations in sociability and sleep patterns, as well as increased seizure susceptibility. Furthermore, immunohistochemistry revealed reduced synaptophysin immunoreactivity in Pigv341E mice, and electrophysiology recordings showed decreased hippocampal synaptic transmission that could underlie impaired memory formation. In single-cell RNA sequencing, Pigv341E-hippocampal cells exhibited changes in gene expression, most prominently in a subtype of microglia and subicular neurons. A significant reduction in Abl1 transcript levels in several cell clusters suggested a link to the signaling pathway of GPI-anchored ephrins. We also observed elevated levels of Hdc transcripts, which might affect histamine metabolism with consequences for circadian rhythm. This new mouse model will not only open the doors to further investigation into the pathophysiology of GPIBD, but will also deepen our understanding of the role of GPI-anchor-related pathways in brain development. Significance statementInherited GPI-anchor biosynthesis deficiencies (IGDs) explain many cases of syndromic intellectual disability. Although diagnostic methods are improving, the pathophysiology underlying the disease remains unclear. Furthermore, we lack rodent models suitable for characterizing cognitive and social disabilities. To address this issue, we generated the first viable mouse model for an IGD that mirrors the condition in human patients with a behavioral phenotype and susceptibility to epilepsy. Using the new model, we obtained neurological insights such as deficits in synaptic transmission that will facilitate understanding of the pathophysiology of IGDs.

neuroscience↗

bioRxiv2019

An engineered monomer binding-protein for α-synucleinefficiently inhibits the proliferation of amyloid fibrils

Removing or preventing the formation of -synuclein aggregates is a plausible strategy against Parkinsons disease. To this end we have engineered the {beta}-wrapin AS69 to bind monomeric -synuclein with high affinity. In cultured cells, AS69 reduced the occurrence of -synuclein oligomers and of visible -synuclein aggregates. In flies, AS69 reduced -synuclein aggregates and the locomotor deficit resulting from -synuclein expression in neuronal cells. In a mouse model based on the intracerebral injection of pre-formed -synuclein seed fibrills (PFFs), AS69 co-injection reduced the density of dystrophic neurites observed three months later. In biophysical experiments in vitro, AS69 highly sub-stoichiometrically inhibited auto-catalytic secondary nucleation processes, even in the presence of a large excess of monomer. We present evidence that the AS69--synuclein complex, rather than the free AS69, is the inhibitory species responsible for sub-stoichiometric inhibition. These results represent a new paradigm that high affinity monomer binders can be strongly sub-stoichiometric inhibitors of nucleation processes.

bioengineering↗