Biology subjects

Vogel, V.

Publications and source records attributed to Vogel, V..

At least 19 recordsLinked to original sources

bioRxiv2026

Magel2 deficiency drives microglial synaptic engulfment and alters neuron-microglia interactions in Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a neurodevelopmental disorder characterized by hypothalamic dysfunction, developmental delay, hyperphagia, and cognitive impairment, yet the cellular mechanisms underlying circuit abnormalities remain unclear. Here, we show that loss of the imprinted gene Magel2 remodels microglial state and function in a mouse model of PWS. Three-dimensional morphometric analysis of hypothalamic microglia revealed reduced structural complexity and contracted territorial domains, emerging early in development and largely independent of obesity. Single-nucleus RNA sequencing of hypothalamic brain tissue identified extensive transcriptional reprogramming involving immune signaling, cellular communication, ribosome function, synaptic organization, and protein translation, with stronger effects in females. Magel2 deficiency also increased microglia-neuron contacts and synaptic engulfment, accompanied by reduced synaptic marker density, suggesting aberrant refinement of hypothalamic circuits. Analyses of human post-mortem hypothalamic tissue from individuals with PWS confirmed microglial structural alterations and increased complement engagement. Ligand-receptor inference further revealed reorganization of microglia-centered communication networks, including altered adhesion, trophic, and immune signaling consistent with enhanced phagocytic states. Together, these findings identify microglial remodeling and increased synaptic engagement as central features of Magel2 deficiency, implicate microglia in hypothalamic circuit dysfunction in PWS, and highlight excessive synaptic pruning as a novel dysfunctional mechanism of PWS.

neuroscience↗

bioRxiv2026

Survival of Streptococcus anginosus in blood is linked to hydrogen peroxide production

Streptococcus anginosus is an opportunistic pathogen causing bacteremia, respiratory tract infections, abscesses, odontogenic infections and has recently been associated with gastric cancer. While numerous genes encoding putative virulence factors have been detected in whole genome sequences, a detailed molecular characterization is missing for most of them. To address putative virulence determinants, we investigated hydrogen peroxide production by S. anginosus and assessed its functional significance for survival in human blood. In Streptococcus pneumoniae the pyruvate oxidase, encoded by the spxB gene, is responsible for H2O2 production and represents a major virulence factor. Interestingly, S. anginosus harbors two genetic variants of the spxB gene, one with high homology to the S. pneumoniae spxB (sequence identity: approx. 94 %) gene, while the other appears to be specific for S. anginosus. Strains carrying the S. pneumoniae variant demonstrate higher H2O2 production (10-20 M) compared to strains harboring the anginosus variant (<1 M). Incubation of S. anginosus strains in human blood showed that bacterial survival was correlated to the amount of hydrogen peroxide production. Assessing H2O2 production in an S. anginosus strain carrying a deletion of the CcpA regulator revealed the control of spxB and H2O2 production by carbon catabolite repression. In conclusion, we found evidence for the presence of a major S. pneumoniae virulence factor in S. anginosus, and we were able to demonstrate that it increases the ability of S. anginosus to survive in human blood.

microbiology↗

bioRxiv2026

Label-Free Quantification of Microtissue Growth Dynamics Using Optical Flow and Mitosis Detection

While geometric constraints shape tissue development, quantifying the resulting growth dynamics remains a central challenge in tissue engineering. Conventional methods often struggle to capture multi-scale kinetics without complex labeling or difficult single-cell tracking. Here, we analyze geometrically controlled growth of microtissues derived from human dermal fibroblasts using time-resolved, label-free brightfield microscopy, combined with optical flow and semi-automated deep learning mitosis detection. By extracting multi-scale flow fields and integrating them with tissue segmentation, we quantify directional tissue dynamics, separating flow into parallel and normal components relative to the local tissue contour. Applying this framework, we contrast the quiescent tissue interior with the advancing growth front where localized dynamics and cell proliferation drive expansion. Our results demonstrate that, compared to the bulk, the growth front exhibits higher fluctuations parallel to the tissue contour, positive mean normal flow, and significantly increased mitotic activity. Furthermore, evaluating flow divergence around mitotic events reveals distinct spatial behaviors: with the onset of mitosis, a contraction and subsequent expansion occurs in the vicinity of the dividing cells. Beyond the immediate cellular neighborhood, the broader regional dynamics remain consistent before and after mitosis onset, with net tissue expansion in proximity to the growth front and contraction within the tissue interior. By extracting continuous kinetic data from easily accessible, label-free brightfield imaging, this approach serves as a non-invasive, complementary tool for evaluating in vitro tissue morphogenesis and growth dynamics. This analytical framework can be expanded to study locally resolved tissue morphogenesis and growth kinetics in other microsystems, ranging from embryos to organoids. Statement of SignificanceUnderstanding how localized cellular forces drive tissue growth is critical for mechanobiology. However, mapping these dynamics traditionally requires complex, invasive fluorescent labeling. We present an accessible, label-free computational framework combining optical flow and deep learning-based mitosis detection to quantify continuous tissue kinematics directly from standard brightfield microscopy. Applying this to 3D microtissues, we reveal a distinct spatial coupling between cell division, local mechanical fluctuations, and directed tissue expansion at the active growth front. This non-invasive approach bridges the gap between single-cell mechanics and macroscopic morphogenesis, offering a versatile tool to monitor complex in vitro model systems-like organoids and bioengineered tissues-without disrupting their native state.

biophysics↗

bioRxiv2026

Molecular Basis of Angicin Activity

Angicin is a class IId bacteriocin produced by Streptococcus anginosus with activity against Gram-positive pathogens, including Listeria monocytogenes and vancomycin-resistant Enterococcus faecium. While the mannose phosphotransferase system (Man-PTS) has been identified as a receptor in L. monocytogenes, its role in streptococci and the structural determinants of Angicin activity remain unclear. Here, we demonstrate that the Man-PTS is required for Angicin susceptibility in Streptococcus constellatus. A transposon mutant (manM::ISS1) showed complete resistance to Angicin and impaired mannose utilization. Structure-activity relationship analysis of truncated and modified peptides localized antimicrobial activity to the C-terminal region, although none of the variants matched the activity of the full-length peptide. Angicin induced membrane depolarization and pore formation in target bacteria. Residual activity in Man-PTS-impaired L. monocytogenes suggests an additional receptor-independent effect at higher concentrations. In vivo toxicity analysis using zebrafish embryos showed low toxicity at active concentrations. These findings identify the Man-PTS as a receptor for Angicin in streptococci and define structural features associated with its antimicrobial activity.

microbiology↗

bioRxiv2025

Bad bugs, new drugs: The antimicrobial peptide C14R is active against the ESKAPE pathogens

The global rise of antimicrobial resistance among the ESKAPE pathogens represents a major challenge to public health. Here, we report the broad-spectrum antibacterial activity of the synthetic antimicrobial and pore-forming peptide C14R against all six ESKAPE species. Using a radial diffusion assay and resazurin-based viability testing, C14R exhibited potent bactericidal effect with minimum inhibitory concentrations (MICs), defined as the lowest concentration of an antimicrobial agent that completely inhibits visible growth of planktonic microorganisms, ranging from 3.4 g/mL (Enterococcus faecium, vancomycin-resistant) to 45.2 g/mL (Klebsiella quasipneumoniae, ESBL). C14R also inhibited biofilm formation by Gram-positive pathogens, with minimum biofilm inhibitory concentrations (MBICs), referring to the minimal concentration required to prevent the development of biofilms, of 15.0 g/mL (Staphylococcus aureus, MRSA) and 22.0 g/mL (E. faecium, VRE), whereas Gram-negatives biofilms showed higher tolerance. Together, these findings demonstrate that C14R retains high activity against multidrug-resistant ESKAPE strains, highlighting its potential as a lead compound for the development of next-generation antimicrobial drugs to expand the portfolio of available antibiotics and brace health systems against emerging severe infections. Author summaryAntibiotic-resistant infections are a growing threat worldwide. A small group of hospital-associated bacteria is especially problematic because they often evade multiple drugs and cause hard-to-treat infections. In this study, we tested the designed antimicrobial peptide C14R as a novel and effective way to fight these bacteria. Peptides are short protein fragments with the ability to puncture and disrupt microbial membranes. We evaluated C14R against six hospital related priority species (so called ESKAPE pathogens) and measured its ability to stop growth and to limit biofilm formation. C14R killed every species we tested and reduced biofilm of two bacteria. Our findings identify C14R as a promising lead for new treatments, particularly for difficult infections and those involving biofilms.

microbiology↗

bioRxiv2025

gFET-based aptasensors technology allows sensitive and specific quantification of the ESKAPE pathogens

The rapid rise of antimicrobial resistance among the ESKAPE pathogens, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp., requires diagnostic technologies capable of fast, simplified and sensitive microbial detection. Conventional culture-based diagnostics remain too time-consuming to guide early therapeutic interventions. Here, we present a graphene field-effect transistor (gFET) aptasensor platform enabling rapid, label-free and highly sensitive quantification of all six ESKAPE pathogens. Each gFET device was functionalized with a specific DNA aptamer selected from literature sources and immobilized via a mixed pyrene-based linker strategy on reduced graphene oxide (rGO). Exposure of the functionalized sensors to logarithmically diluted bacterial suspensions (10-105 CFU mL-) produced characteristic and concentration-dependent shifts in source-drain current ({Delta}IDS). For all pathogen-specific aptamers, {Delta}IDS correlated linearly with bacterial load (R2 = 0.90-1.00), while non-target bacteria generated only low-level, unspecific fluctuations. Limits of detection ranged from 10 to 1000 bacterial cells depending on the aptamer. Together, these results demonstrate that aptamer-functionalized rGO-FETs provide a robust, scalable and highly specific electronic biosensing architecture capable of distinguishing clinically relevant multidrug-resistant pathogens with excellent analytical performance. Author summaryAntimicrobial-resistant bacteria pose a growing threat to global health, especially the so-called ESKAPE pathogens, which frequently cause hospital-acquired infections and are increasingly difficult to treat. Current diagnostic methods can take several days, delaying the start of effective therapy. In our work, we developed a fast and highly sensitive biosensor that uses electrically conductive GO and short DNA molecules, called aptamers, to recognize specific bacteria. When a pathogen binds to its matching aptamer on the sensor surface, the electrical signal of the graphene changes in a measurable way. We tested ESKAPE species and showed that all of the investigated aptamers detect only their intended bacterial targets, even at very low concentrations. Importantly, the sensors respond within minutes and do not require any labelling or complex sample preparation. Our technology demonstrates how graphene-based aptasensors can support rapid and accurate detection of dangerous bacterial pathogens and could ultimately help clinicians make faster decisions in treating infections.

microbiology↗

bioRxiv2025

Osmotic niche changes as multifaceted trigger of cellular regenerative processes in organ injury

Cell niches are organ-specific and characterized by a variety of distinct biophysical cues, including mechanics and osmolality. Injury disrupts this cellular environment and marks the start of regenerative processes. It remains unclear whether bone fracture alters the osmolality of bone marrow, and how associated changes in the extracellular matrix (ECM) affect marrow-resident cells in the onset of regeneration. Here we present analyses of human tissue samples indicating that osmolality differences among tissue types lead to a sudden drop in bone marrow osmolality upon fracture, which in turn enhances ECM viscoelasticity. We reveal that a sudden osmolality drop, mimicked in vitro by lowering ion concentrations, triggers bone regenerative processes in mesenchymal stromal cells (MSCs), markedly enhancing their spreading, proliferation, and osteogenic differentiation while residing in osmolality- responsive viscoelastic ECM. Conversely, in non-physiologically elastic ECM, similarly increased osmolality augments MSC osteogenic differentiation, suggesting that ECM viscous dissipation redirects cellular responses to osmotic changes. Mechanistically, the regenerative function of the osmolality drop depends on the matrix providing cell-adhesion ligands and physiological viscoelastic properties. Sequencing data show altered gene expression already two hours after differentiation start, with distinct characteristics related to chromatin structural changes specifically associated with hypoosmolality. Our results suggest that the osmolality drop serves as fast-acting regenerative stimulus for MSCs by extracellularly enhancing matrix viscoelasticity, while altering chromatin structure intracellularly. This stimulus upon injury potentially orchestrates the individual responses of multiple cell types within a niche, facilitating a collective action towards regeneration. Learning how to leverage osmotic cues to induce regenerative cascades may eventually advance local and personalized therapeutic strategies for patients with impaired healing capacity. We anticipate that the integration of osmotic and mechanical ECM properties, as demonstrated in our assay, will catalyze advanced 3D cell culture systems and offer new perspectives on material design in tissue engineering, disease modeling, and mechanobiology.

bioengineering↗

bioRxiv2025

SEVI Fibrils are Induced by Bacterial Surface Molecules and Exert Antimicrobial Activity Against ESKAPE Pathogens

The semen-derived enhancer of viral infection (SEVI) is an amyloid fibril formed by the self-assembly of the PAP248-286 peptide, a cleavage product of prostatic acid phosphatase, which is naturally present in human seminal plasma. Beyond its previously described role in HIV transmission, findings highlight a physiological function for SEVI in innate immunity. As many amyloids display antimicrobial effects, we tested SEVI fibrils for antibacterial activity against microbial ESKAPE pathogens and urogenital bacteria, including Pseudomonas aeruginosa, Klebsiella quasipneumoniae, Escherichia coli, Acinetobacter baumannii, Staphylococcus aureus, Streptococcus agalactiae and Listeria monocytogenes. SEVI exhibited direct dose-dependent antibacterial effects in radial diffusion and survival assays, with activity observed at physiologically relevant concentrations. Bacterial surface molecules such as lipopolysaccharides and lipoteichoic acid induced the formation of SEVI fibrils, as confirmed by kinetic assays. Preincubation with epigallocatechin gallate, a fibril disruptor, abolished SEVIs antibacterial activity, pointing to the importance of its fibrillar structure. Mechanistic studies and electron microscopy revealed limited bacterial membrane disruption and the intracellular accumulation of polyphosphate granules in P. aeruginosa, indicating a stress response. In conclusion, SEVI exerts a potent antibacterial activity against pathogens found in the urogenital tract, indicating a potential physiological role in vaginal mucosal immunity.

microbiology↗

bioRxiv2024

Force-dependent Reorganization and Mechanostability of the Izumo1:Juno Complex Involved in Human Fertilization

Izumo1:Juno-mediated adhesion between sperm and egg cells is essential for mammalian sexual reproduction. However, conventional biophysical and structural approaches have provided only limited functional insights. Using atomic force microscopy-based single- molecule force spectroscopy and all-atom steered molecular dynamic simulations, we explored the role of mechanical forces in regulating the human Izumo1:Juno complex. Our findings reveal a multi-state catch bond capable of withstanding forces up to 600 pN- mechanostability rarely observed among eukaryotic protein complexes. We further found that this mechanostability was impaired in the infertility-associated mutant, JunoH177Q. Detailed steered molecular dynamics simulations show how force-dependent reorganization of the Izumo1:Juno complex engages new binding conformations to achieve this state of high mechanostability. Overall, this study significantly enhances our understanding of the mechanical underpinnings that regulate human fertilization.

biophysics↗

bioRxiv2024

Onco-fetal protein Nogo-A restricts human and mouse glioma vascularization and growth via VEGF-Notch-hippo-metabolic signaling

Glioblastoma is one of the most deadly human cancers characterized by high degrees of vascularization, but targeting its vasculature has resulted in very limited success so far. Angiogenesis, the growth of new blood vessels, is highly dynamic during brain development, enters a mostly quiescent state in the adult homeostatic brain, and is reactivated in vascular-dependent CNS diseases including brain tumors. In consequence, a better understanding of the relevance of the onco-fetal axis - describing the reactivation of fetal signaling programs in tumors - in endothelial- and perivascular cells of the human brain tumor vasculature harbors great translational potential, yet remains poorly defined. In development, neurovascular link (NVL) molecules guide both neuronal growth cones as well as capillary endothelial tip cells. Nogo-A is an NVL molecule known to inhibit axonal growth in the developing and adult CNS and to restrict angiogenesis during brain development, but its role in the mouse and human brain tumor vasculature along the onco-fetal axis remains unknown. Here, we characterize Nogo-A as an onco-fetal protein expressed in the neurovascular unit (NVU) in human fetal brains and human gliomas in vivo that negatively regulates sprouting angiogenesis and endothelial tip cells in glioma vascularization. The Nogo-A-specific Delta 20 domain restricts angiogenic sprouting and branching and promotes vascular normalization while inhibiting glioma growth in experimental gliomas. Moreover, Nogo-A expression in tumor cells negatively correlate/s with glioma malignancy in vivo. In vitro, Nogo-A Delta 20 reduced human brain- and brain tumor endothelial cell (HBMVEC, HBTMVEC) and human umbilical vein endothelial cell (HUVEC) spreading, migration, and sprouting, in a dose-dependent manner and inhibited filopodia extension glucose metabolism. Mechanistically, RNA sequencing of Nogo-A Delta 20-treated HBMVECs and HBTMVECs revealed Nogo-A Delta 20-induced positive regulation of the angiogenesis-inhibiting Dll4-Notch-pathway and inhibition of the angiogenesis-promoting VEGF-VEGFR and Hippo-YAP-TAZ pathways, whereas metabolomics and functional metabolic assays revealed Nogo-A Delta 20-induced negative regulation of endothelial glycolysis in HBMVECs and HBTMVECs. These findings characterize Nogo-A as an onco-fetal protein in the human glial brain tumor vasculature and identify Nogo-A Delta 20 signaling as an important negative regulator of human glioma vascularization and growth. Enhancing Nogo-A signaling may be an attractive alternative or combinatorial anti-angiogenic therapy to restrict human glioma/glioblastoma vascularization and growth.

neuroscience↗

bioRxiv2023

Tissue Transglutaminase 2 has higher affinity for relaxed than for stretched fibronectin fibers

Tissue transglutaminase 2 (TG2) plays a vital role in stabilizing extracellular matrix (ECM) proteins through enzymatic crosslinking during tissue growth, repair, and inflammation. TG2 also binds non-covalently to fibronectin (FN), an essential component of the ECM, facilitating cell adhesion, migration, proliferation, and survival. However, the interaction between TG2 and fibrillar FN remains poorly understood, as most studies have focused on soluble or surface-adsorbed FN or FN fragments, which differ in their conformations from insoluble FN fibers. Using a well-established in vitro FN-fiber stretch assay, we discovered that the binding of a crosslinking enzyme to ECM fibers is mechano-regulated. TG2 binding to FN is tuned by the mechanical tension of FN fibers, whereby TG2 predominantly co-localizes to low-tension FN fibers, while fiber stretching reduces their affinity for TG2. This mechano-regulated binding relies on the proximity between the N-terminal {beta}-sandwich and C-terminal {beta}-barrels of TG2. Crosslinking mass spectrometry (XL-MS) revealed a novel TG2-FN synergy site within TG2s C-terminal {beta}-barrels that interacts with FN regions outside of the canonical gelatin binding domain, specifically FNI2 and FNIII14-15. Combining XL-MS distance restraints with molecular docking reveals the mechano-regulated binding mechanism between TG2 and modules FNI7-9 by which mechanical forces regulate TG2-FN interactions. This highlights a previously unrecognized role of TG2 as a tension sensor for FN fibers. This novel interaction mechanism has significant implications in physiology and mechanobiology, including how force regulate ECM deposition and maturation, and how TG2 mediates cell-ECM adhesion in health and in various pathophysiological processes. Data are available via ProteomeXchange with identifier PXD043976.

molecular biology↗

bioRxiv2023

Salmonella-driven Intestinal Edema in Mice is Characterized by Tensed Fibronectin Fibers

Intestinal edema is a common manifestation of numerous gastrointestinal diseases and is characterized by the accumulation of fluid in the interstitial space of the intestinal wall. Technical advances in laser capture microdissection and low-biomass proteomics now allow us to specifically characterize the intestinal edema proteome. Our data identifies a high abundance of antimicrobial factors, but also highlights major contributions from the blood clotting system, extracellular matrix (ECM) and protease - protease inhibitor networks. The ECM is a complex fibrillar network of macromolecules that provides structural and mechanical support to the intestinal tissue. One abundant component of the ECM observed in the Salmonella-driven intestinal edema is the mechanosensitive glycoprotein fibronectin. Using mechanosensitive staining of fibronectin reveals a solely tensed molecular conformation of fibronectin fibers present in the edema, in contrast to other cecal tissue areas, despite the high abundance of proteases able to cleave fibronectin. Co-staining for fibrin(ogen) indicates the formation of a provisional matrix, similar to what is observed in response to skin injury. The absence of low tensional fibronectin fibers and the additional finding of a high number of protease inhibitors in the edema proteome could indicate a critical role of stretched fibronectin fibers in maintaining tissue integrity in the severely inflamed cecum. Understanding these processes may provide valuable functional diagnostic markers of intestinal disease progression. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=104 SRC="FIGDIR/small/550515v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@1318c52org.highwire.dtl.DTLVardef@1f35d21org.highwire.dtl.DTLVardef@67370borg.highwire.dtl.DTLVardef@4ec7e6_HPS_FORMAT_FIGEXP M_FIG C_FIG

pathology↗

bioRxiv2023

Single-cell transcriptomics analysis reveals extracellular matrix remodelling in carious human dental pulp

The carious lesion is a bacteria caused destruction of tooth mineralized matrices marked by concurrent tissue reparative and immune responses in the dental pulp. While major molecular players in tooth pulp decay have been uncovered, a detailed map of the molecular and cellular landscape of the diseased pulp is still missing. Here we used single-cell RNA sequencing analysis, to generate a comprehensive single-cell atlas of the carious human dental pulp tissue. Our data demonstrated modifications in various cell clusters of the carious pulp, such as immune cells, mesenchymal stem cells (MSC) and fibroblasts, when compared to the healthy dental pulp. These changes include upregulation of genes encoding extracellular matrix (ECM) components and the enrichment of the fibroblast cluster with myofibroblasts. Assessment of the Fibronectin fibres mechanical strain showed a significant tension reduction in the carious human pulp, compared to the healthy one. Collectively, the present data demonstrate molecular, cellular and biomechanical alterations in the carious pulp tissue, indicative of extensive ECM remodelling and reminiscent of fibrosis observed in other organs.

cell biology↗

bioRxiv2022

Mechanotransduction coordinates extracellular matrix protein homeostasis promoting longevity in C. elegans

Although it is postulated that dysfunctional extracellular matrices (ECM) drive aging and disease, how ECM integrity assures longevity is unknown. Here, using proteomics and in-vivo monitoring of fluorescently tagged ECM proteins, we systematically examined the ECM composition during Caenorhabditis elegans aging revealing three distinct collagen dynamics. We show that age-dependent stiffening of inert collagen was slowed by longevity interventions through prolonged replenishing of collagens. In genetic and automated lifespan screens for the regulators that drive this remodeling, we identify hemidesmosome-containing structures that span from the exoskeletal ECM through the hypodermis, basement membrane ECM, to the muscles, coupling mechanical forces to adjust ECM gene expression across tissues. The hemidesmosome tension-induced adaptation is mediated via transcriptional co-activator YAP. Our data reveal a novel mechanism of mechano-coupling and synchronizing of two functionally distinct and spatially distant ECMs that is indispensable for longevity. Thus, besides signaling molecules, mechanotransduction-coordinated ECM remodeling systemically promotes healthy aging. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=199 SRC="FIGDIR/small/505802v1_ufig1.gif" ALT="Figure 1"> View larger version (60K): org.highwire.dtl.DTLVardef@1b45b6dorg.highwire.dtl.DTLVardef@1de8e80org.highwire.dtl.DTLVardef@5da7b2org.highwire.dtl.DTLVardef@acc577_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIProteomics, genetics screen, and automated lifespan assays of >55000 animals all point to hemidesmosome-containing structures for the mechano-regulation of ECM homeostasis and longevity C_LIO_LICoupling of biomechanical properties of two ECMs with underlying cellular signaling C_LIO_LITranscriptional co-activator YAP-1 is required for longevity and pressure-induced collagen homeostasis C_LI

molecular biology↗

bioRxiv2022

Blockage of Lamin-A/C loss diminishes the pro-inflammatory macrophage response

Mutations and defects in nuclear lamins can cause major pathologies in affected tissues. Recent studies have also established potential links between lamins, inflammation, and inflammatory diseases but the underlying molecular mechanisms are unknown. We now report that pro-inflammatory activation of macrophages reduces levels of Lamin-A/C to augment pro-inflammatory gene expression and cytokine secretion. We show that activation of bone-marrow derived macrophages (BMDMs) degrades Lamin-A/C, as preceded by its phosphorylation, which is mediated by Caspase-6 and CDK1, respectively. Inhibiting Lamin-A/C phosphorylation and degradation severely inhibits pro-inflammatory gene expression and cytokine secretion. Using LPS-activated Lamin-A/C Knock Out BMDMs, we confirmed that the activation of the IFN-{beta}-STAT pathway is amplified due to Lamin-A/C reduction, which ultimately augments the pro-inflammatory response. As Lamin-A/C is a previously unappreciated regulator of the pro-inflammatory macrophage response, our findings could provide novel opportunities to treat inflammatory diseases. In first proof-of-concept studies we show that macrophage pro-inflammation, as induced by Lipopolysaccharide or pathogenic E. coli, could be reduced by inhibiting Lamin-A/C phosphorylation and degradation. The inhibition of macrophage pro-inflammation could also be achieved by inhibiting members of the Lamin-A/C regulated IFN-{beta}-STAT pathway, i.e., phospho-STAT1 and phospho-STAT3. This newly found mechanism to suppress the pro-inflammatory response of macrophages will provoke a re-thinking of how inflammation can be addressed therapeutically.

cell biology↗

bioRxiv2021

Differentiation of mouse embryonic stem cells into cells with spermatogonia-like morphology with chemical intervention-dependent increased gene expression of LIM homeobox 1 (Lhx1).

During the development of the male germline, spermatogonial stem cells (SSCs) originate from gonocytes that differentiate from primordial germ cells (PGCs). In the developing and regenerating mouse testis, expression of the gene LIM homeobox 1 (Lhx1) marks the most undifferentiated SSCs. However, an enrichment of Lhx1 expression in spermatogonia-like cells generated in vitro has not been reported so far. Previously, it was shown that a chemical intervention in male mouse embryonic stem (ES) cells in serum culture, including a timed combination of the SIRT1 inhibitor Ex-527, the DNA methyltransferase inhibitor RG-108 and the electrophilic redox cycling compound tert-butylhydroquinone (tBHQ), was associated with molecular markers of the PGC to gonocyte differentiation process. Here, we report the in vitro differentiation of male mouse ES cells, cultured under dual chemical inhibition of GSK3{beta} and MEK (termed 2i) with leukemia inhibitory factor (LIF) (termed 2iL) and serum, into cells with spermatogonia-like morphology (CSMs) and population-averaged expression of spermatogonia-specific genes. This was achieved by the removal of 2iL and a specific schedule of 2 partial medium replacements per day with alternating 8-hour and 16-hour intervals over a period of 32 days. Combination of this new cell culture protocol with the previously reported chemical intervention in ES cells changed the population-averaged expression of spermatogonia- and gonocyte-specific genes during the differentiation process and increased the population-averaged gene expression of Lhx1 in the resulting CSMs compared to CSMs without chemical intervention. Furthermore, we detected single CSMs with a strong nuclear LHX1/5 protein signal only in the chemical intervention group. Our results provide the first experimental evidence for the generation of CSMs with an enrichment of Lhx1 expression in vitro. We propose that further investigation of the CSMs generated with this in vitro system may provide new insights into male germline and stem cell development.

cell biology↗

bioRxiv2021

Angicin, a novel bacteriocin of Streptococcus anginosus

As a conserved defense mechanism, many bacteria produce antimicrobial peptides, called bacteriocins, which give a colonization advantage in a multispecies environment. Here the first bacteriocin of Streptococcus anginosus, designated Angicin, is described. S. anginosus is commonly described as a commensal, however it also possesses a high pathogenic potential. Therefore, understanding factors contributing to its host colonization and persistence are important. A radial diffusion assay was used to identify S. anginosus BSU 1211 as a potent bacteriocin producer. By genetic mutagenesis the background of bacteriocin production and the bacteriocin gene itself were identified. Synthetic Angicin shows high activity against closely related streptococci, listeria and vancomycin resistant enterococci. It has a fast mechanism of action and causes a membrane disruption in target cells. Angicin, present in cell free supernatant, is insensitive to changes in temperature from -70 to 90 {degrees}C and pH values from 2-10, suggesting that it represents an interesting compound for potential applications in food preservation or clinical settings.

microbiology↗

bioRxiv2021

CdrS is a global transcriptional regulator influencing cell division in Haloferax volcanii

Transcriptional regulators that integrate cellular and environmental signals to control cell division are well known in bacteria and eukaryotes, but their existence is poorly understood in archaea. We identified a conserved gene (cdrS) that encodes a small protein and is highly transcribed in the model archaeon Haloferax volcanii. The cdrS gene could not be deleted, but CRISPRi-mediated repression of the cdrS gene caused slow growth, cell division defects, and changed the expression of multiple genes and their products associated with cell division, protein degradation and metabolism. Consistent with this complex regulatory network, overexpression of cdrS inhibited cell division, whereas overexpression of the operon encoding both CdrS and a tubulin-like cell division protein (FtsZ2) stimulated division. ChIP-Seq identified 18 DNA-binding sites of the CdrS protein including one upstream of the promoter for diadenylate cyclase, which is an essential gene involved in c-di-AMP signalling implicated in the regulation of cell division. These findings suggest that CdrS is a transcription factor that plays a central role in a regulatory network coordinating metabolism and cell division. ImportanceCell division is a central mechanism of life, and is essential for growth and development. Bacteria and Eukarya have different mechanisms for cell division, which have been studied in detail. In contrast, cell division in Archaea is still understudied, and its regulation is poorly understood. Interestingly, different cell division machineries appear in the Archaea, with the Euryarchaeota using a cell division apparatus based on the tubulin-like cytoskeletal protein FtsZ, as in bacteria. Here we identify the small protein CdrS as essential for survival and a central regulator of cell division in the Euryarchaeon Haloferax volcanii. CdrS also appears to coordinate other cellular pathways including synthesis of signalling molecules and protein degradation. Our results show that CdrS plays a sophisticated role in cell division, including regulation of numerous associated genes. These findings are expected to initiate investigations into conditional regulation of division in archaea.

microbiology↗