Biology subjects

Radbruch, H.

Publications and source records attributed to Radbruch, H..

10 recordsLinked to original sources

bioRxiv2026

Stroke-induced lipocalin-2-expressing red pulp macrophages reprogram peripheral immunity

Acute ischemic stroke (AIS) induces profound systemic immune alterations that contribute to infection susceptibility. Here, we identify lipocalin-2 (LCN-2) as a rapidly induced and conserved regulator of stroke-associated immunosuppression. Using 3-MACE-Seq, cytokine profiling, and immunofluorescence in C57BL/6J mice subjected to transient middle cerebral artery occlusion (tMCAO), we show that LCN-2 is strongly upregulated in splenic red pulp macrophages (RPMs) within 24 hours and again 7 days post-tMCAO. LCN-2-expressing RPMs form immunological synapses with CD3+ T cells, thereby impacting T cell trafficking. Recombinant LCN-2 directly reprogrammed T cells and monocytes toward hyporesponsive, tolerogenic phenotypes by suppressing inflammatory cytokines, impairing chemotaxis, enhancing phagocytosis, and uncoupling oxidative burst. Human spleens likewise displayed LCN-2-expressing CD68+ RPMs, and LCN-2 preconditioning of monocytes reproduced reduced HLA-DR, CD80, CD206, and ROS with increased uptake of E. coli bioparticles. These findings identify LCN-2 signaling as a central orchestrator of stroke-induced peripheral immunoreprogramming and a potential therapeutic target to mitigate post-stroke immunodepression. SummaryAcute ischemic stroke induces LCN-2 in splenic red pulp macrophages, which reprogram T cells and monocytes toward tolerogenic, hyporesponsive states. Mouse and human data identify LCN-2 as a driver of peripheral immunodepression and a potential target to reduce infection risk. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=143 SRC="FIGDIR/small/733904v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@fb0caforg.highwire.dtl.DTLVardef@1fdcd41org.highwire.dtl.DTLVardef@1ae99b0org.highwire.dtl.DTLVardef@1ec0837_HPS_FORMAT_FIGEXP M_FIG Graphical abstract C_FIG

immunology↗

bioRxiv2025

Cryo-mtscATAC-seq for single-cell mitochondrial DNA genotyping and clonal tracing in archived human tissues

High-throughput clonal tracing of primary human samples relies on naturally occurring barcodes, such as somatic mitochondrial DNA (mtDNA) mutations detected via single-cell ATAC-seq (mtscATAC-seq). Fresh-frozen clinical specimens preserve tissue architecture but compromise cell integrity, thereby precluding their use in multi- omic approaches such as mitochondrial genotyping at single-cell resolution. Here, we introduce Cryo-mtscATAC-seq, a broadly applicable method for diverse pathophysiological contexts to isolate nuclei with their associated mitochondria ("CryoCells") from frozen samples for high-throughput clonal analysis. We applied Cryo-mtscATAC-seq to the neurodegenerated human brain, glioblastoma (GBM), pediatric neuroblastoma, and human aorta, and implemented mitobender, a computational tool to reduce ambient mtDNA in single-cell assays. Our approach revealed regional clonal gliogenesis and microglial expansions in amyotrophic lateral sclerosis (ALS), persistence of oligodendrocyte progenitor cell (OPC)-like clones in GBM recurrence, mtDNA depth heterogeneity after neuroblastoma chemotherapy, and oligoclonal proliferation of smooth muscle cells in human aorta. In conclusion, Cryo-mtscATAC-seq broadly extends mtDNA genotyping to archival frozen specimens across tissue types, opening new avenues for investigation of cell state- informed clonality in human health and disease.

systems biology↗

bioRxiv2025

circVDJ-seq for T cell clonotype detection in single-cell and spatial multi-omics

Monitoring T cell repertoires in human tissues provides important insights into immune response mechanisms in cancer, infectious diseases, and autoimmunity. However, retrieving VDJ information from single-cell and spatial transcriptomics workflows with 3-barcoding of cDNA remains resource-intensive or requires specialized sequencing equipment. Here, we introduce circVDJ-seq for simplified and cost-efficient T cell receptor (TCR) profiling from 3-directed workflows like single-cell or single-nucleus RNA sequencing, ATAC+RNA multi-omics, and spatial transcriptomics. Application of circVDJ-seq to freshly resected neuroblastomas and postmortem lymph nodes affected by pneumonia or COVID-19 reveals distinct immune microenvironments and T cell clonality patterns, highlighting broad utility across diverse clinical contexts.

genomics↗

bioRxiv2025

Complex Human Hair Bearing Skin Organoids as Model for Herpes Simplex Virus 1 Infection in the Skin

Epithelial surfaces are the initial site of Herpes Simplex Virus 1 (HSV-1) infection. After latency establishment in the peripheral nervous system, reactivation can lead to skin pathologies. To reflect the complexity of skin we used complex human hair bearing skin organoids as a new model system for HSV-1 infection. We analyzed spread of the infection through the three-dimensional tissue and the cell type specific host response in a spatial temporal manner. Single-cell-resolution spatial transcriptomics and imaging shows a restricted viral infection in keratinocytes of the epidermis and hair follicles. The host factor IER3 is upregulated in papillary fibroblasts of the dermis as the infection progresses through the tissue. In keratinocytes of the stratum basale, we find IRF3 upregulated in infected but also virus negative cells, suggesting a signaling mechanism to initiate antiviral responses. Furthermore, we find a cell type specific inflammatory response with an upregulation of TNFSF9 in dermal fibroblasts and TNF in keratinocytes. TNF target genes are induced in neighboring uninfected cells suggesting the induction of a localized inflammatory reaction to suppress viral infection. In summary, our findings position human hair-bearing skin organoids as a highly physiological model system for studying HSV-1 pathogenesis and reveal spatially organized host responses.

microbiology↗

bioRxiv2023

VoltRon: A Spatial Omics Analysis Platform for Multi-Resolution and Multi-omics Integration using Image Registration

The growing number of spatial omic technologies have created a demand for computational tools capable of managing, storing, and analyzing spatial datasets with multiple modalities and spatial resolutions. Meanwhile, computer vision is becoming an integral part of processing spatial data readouts where image registration and spatial data alignment of tissue sections are essential prior to data integration. Hence, there is a need for computational platforms that analyze data across spatial datasets with diverse resolutions as well as those that manipulate and process images of microanatomical tissue structures. To this end, we have developed VoltRon, a novel R package for spatial omics analysis with a unique data structure that accommodates data readouts with many levels of spatial resolutions (i.e., multi-resolution) including regions of interest (ROIs), spots, single cells, and even subcellular entities such as molecules. To connect and integrate these spatially diverse omic profiles, VoltRon accounts for spatial organization of tissue blocks (samples), layers (sections) and assays given a multi-resolution collection of spatial data readouts. An easy-to-use computer vision toolbox, OpenCV, is fully embedded in VoltRon that allows users to both automatically and manually register spatial coordinates across adjacent layers for data transfer without the need for external software tools. VoltRon is implemented in the R programming language and is freely available at https://github.com/BIMSBbioinfo/VoltRon.

bioinformatics↗

bioRxiv2022

Biomolecular Tau condensation is linked to Tau accumulation at the nuclear envelope

Biomolecular condensation of the neuronal microtubule-associated protein Tau (MAPT) can be induced by coacervation with polyanions like RNA, or by molecular crowding. Tau condensates have been linked to both functional microtubule binding and pathological aggregation in neurodegenerative diseases. We find that molecular crowding and coacervation with RNA, likely coexisting in the cytosol, synergize to enable Tau condensation at physiological buffer conditions and produce condensates with a strong affinity to charged surfaces. During condensate-mediated microtubule polymerization, this synergy enhances bundling and spatially arranges microtubules. We further show that different Tau condensates efficiently induce pathological Tau in cells, including small accumulations at the nuclear envelope that correlate with nucleocytoplasmic transport deficits. Fluorescent lifetime imaging reveals different molecular packing densities of Tau in cellular accumulations, and a condensate-like density for nuclear envelope Tau. These findings suggest that a complex interplay between interaction partners, post-translational modifications, and molecular crowding regulates the formation and function of Tau condensates. Conditions leading to prolonged existence of Tau condensates may induce the formation of seeding-competent Tau and lead to distinct cellular Tau accumulations.

molecular biology↗

bioRxiv2021

Intra-individual Physiomic Landscape of Pyramidal Neurons in the Human Neocortex

Understanding the functional principles of the human brain requires deep insight into the neuronal and network physiology. To what extent such principles of cellular physiology and synaptic interactions are common across different human individuals is unknown. We characterized the physiology of ~1200 pyramidal neurons and ~1400 monosynaptic connections using advanced multineuron patch-clamp recordings in slices from human temporal cortex. To disentangle within and between individual sources of heterogeneity, we recorded up to 100 neurons per single subject. We found that neuronal, but not synaptic physiology varied with laminar depth. Connection probability was ~15% throughout layer 2-3. Synaptic amplitudes exhibited heavy-tailed distributions with an inverse power law relationship to short term plasticity. Neurons could be classified into four functional subtypes. These general principles of microcircuit physiology were common across individuals. Our study advances the understanding of human neuron and synaptic diversity from an individual and phenotypic perspective.

neuroscience↗

bioRxiv2020

Olfactory transmucosal SARS-CoV-2 invasion as port of Central Nervous System entry in COVID-19 patients

The newly identified severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19, a pandemic respiratory disease presenting with fever, cough, and often pneumonia. Moreover, thromboembolic events throughout the body including the central nervous system (CNS) have been described. Given first indication for viral RNA presence in the brain and cerebrospinal fluid and in light of neurological symptoms in a large majority of COVID-19 patients, SARS-CoV-2-penetrance of the CNS is likely. By precisely investigating and anatomically mapping oro- and pharyngeal regions and brains of 32 patients dying from COVID-19, we not only describe CNS infarction due to cerebral thromboembolism, but also demonstrate SARS-CoV-2 neurotropism. SARS-CoV-2 enters the nervous system via trespassing the neuro-mucosal interface in the olfactory mucosa by exploiting the close vicinity of olfactory mucosal and nervous tissue including delicate olfactory and sensitive nerve endings. Subsequently, SARS-CoV-2 follows defined neuroanatomical structures, penetrating defined neuroanatomical areas, including the primary respiratory and cardiovascular control center in the medulla oblongata.

neuroscience↗

bioRxiv2019

Intravital quantification of absolute cytoplasmic B cell calcium reveals dynamic signaling across B cell differentiation stages

Development, function and maintenance of lymphocytes largely depend upon the cellular mobilization and storage of Ca2+ ions. In B lymphocytes, the absolute amount of calcium mobilized and retained after cell signaling remains unknown, athough it is a crucial part of their selection within germinal centers and differentiation into plasma cells. Here, we introduce the novel reporter mouse strain YellowCaB that expresses the genetically encoded calcium indicator TN-XXL in CD19+ lymphocytes. The construct consists of the electrondonor fluorophore eCFP and the acceptor citrine, linked by a calcium sensitive domain. Its conformation and therefore donor quenching is directly linked to cytosolic calcium concentrations. By combining intravital two-photon fluorescence lifetime microscopy with our numerical approach for phasor-based analysis, we are able to extract absolute cytoplasmic calcium concentrations in activated B cells for the first time in vivo. We show that calcium concentrations in B cells are highly dynamic and fluctuations persist in extrafollicular B cells with functional relevance.

immunology↗

bioRxiv2019

Low-Density Granulocytes are a novel immunopathological feature in both Multiple Sclerosis and Neuromyelitis optica spectrum disorder.

ObjectiveTo investigate whether low-density granulocytes (LDGs) are a immunophenotypic feature of patients with multiple sclerosis (MS) and/or neuromyelitis optica spectrum disorder (NMOSD).\n\nMethodsBlood samples were collected from 26 patients with NMOSD and 20 patients with MS, as well as from 18 patients with Systemic Lupus Erythematosus (SLE) and 23 Healthy Donors (HD). We isolated peripheral blood mononuclear cells (PBMCs) with density gradient separation and stained the cells with antibodies against CD14, CD15, CD16, and CD45, and analysed the cells by flow cytometry or imaging flow cytometry. We defined LDGs as CD14-CD15high and calculated their share in total PBMC leukocytes (CD45+) as well as the share of CD16hi LDGs. Clinical data on disease course, medication, and antibody status were obtained.\n\nResultsLDGs were significantly more common in MS and NMOSD than in HDs, comparable to SLE samples (median values HD 0.2%, MS 0.9%, NMOSD 2.1%, SLE 4.3%). 0/23 of the HDs, but 17/20 NMOSD and 11/17 MS samples as well as 13/15 SLE samples had at least 0.7 % LDGs. NMOSD patients without continuous immunosuppressive treatment had significantly more LDGs compared to their treated counterparts. LDG nuclear morphology ranged from segmented to rounded, suggesting a heterogeneity within the group.\n\nConclusionLDGs are a feature of the immunophenotype in some patients with MS and NMOSD.

immunology↗