Biology subjects

Reumann, D.

Publications and source records attributed to Reumann, D..

7 recordsLinked to original sources

bioRxiv2026

Spatiotemporal control of STING activation and saRNA delivery decouples humoral and cellular immunity

Self-amplifying mRNA (saRNA) vaccine formulations link the location and timing of antigen expression to innate immune stimulation by both RNA cargo and carrier. We hypothesized that targeting a polymeric STING agonist prodrug (polySTING) to antigen-presenting cells (APCs) independently of saRNA delivery could tune vaccines responses without limiting saRNA expression. By varying the time and location of STING signaling relative to saRNA delivered by muscle-restricted (polyplex, PP) and lymph node-draining (lipid nanoparticle, LNP) saRNA formulations, we studied how spatiotemporal colocalization of type I interferon (IFN-I) and antigen expression impacts innate and adaptive vaccine responses. Co-administering PP + polySTING decreased antigen-specific adaptive type 1 responses by mismatching early lymph node IFN-I and later arriving antigen; this could be reversed by delaying polySTING delivery timing. Conversely, synchronizing early LNP saRNA delivery and polySTING IFN-I in the lymph node boosted saRNA type 1 T cell responses without impacting humoral immunity, which re-directed antigen-intrinsic immune skewing and enhanced protection against pulmonary Acinetobacter baumannii challenge. Collectively, these findings define formulation-specific innate immune responses to saRNA vaccines and establish APC-targeted adjuvants as a strategy to tune saRNA vaccine immunogenicity.

immunology↗

bioRxiv2026

A uniform tissue-clearing framework and mesoSPIM-ultra enable cm-scale single-neuron tracing

Tissue-clearing and light-sheet microscopy have transformed volumetric imaging of intact organs, yet limited mechanistic understanding of dehydration-based clearing continues to constrain rational protocol design and broader applicability. Here, we define the cardinal chemical and physical principles underlying dehydration-based tissue-clearing and establish a new pipeline for large-volume imaging. To maximize imaging performance, we developed the "mesoSPIM-ultra", an upgraded mesoSPIM platform with a temperature-controlled sample chamber, a large field-of-view (FoV) camera and specialized optics to achieve long-working-distance, high-resolution imaging of cleared samples. We applied this approach to investigate the projectome of Chx10+ neurons, a cell population with complex axonal morphologies along the entire mouse spinal-cord and brain, and implicated in ipsilateral orienting behaviors. By combining behavioral analysis with post-hoc single-neuron reconstructions, we revealed previously inaccessible branching architectures and long-range projections extending from the brainstem to the spinal cord. Together, our work establishes a mechanistic foundation for tissue-clearing and scalable imaging.

neuroscience↗

bioRxiv2025

Label-free biochemical imaging and timepoint analysis of neural organoids via deep learning-enhanced Raman microspectroscopy

Three-dimensional organoids have emerged as powerful models for studying human development, disease and drug response in vitro. Yet, their analysis remains constrained by standard imaging and characterisation techniques, which are invasive, require exogenous labelling and offer limited multiplexing. Here, we present a non-invasive, label-free imaging platform that integrates Raman microspectroscopy with deep learning-based hyperspectral unmixing for unsupervised, spatially resolved biochemical analysis of neural organoids. Our approach enables high-resolution mapping of cellular and subcellular structures in both cryosectioned and intact organoids, achieving improved imaging accuracy and robustness compared to conventional methods for hyperspectral analysis. Using our platform, we demonstrate volumetric imaging of a neural rosette within a neural organoid, and interrogate changes in biochemical composition during early developmental stages in intact neural organoids, revealing spatiotemporal variations in lipids, proteins and nucleic acids. This work establishes a versatile framework for high-content, label-free (bio)chemical phenotyping with broad applications in organoid research and beyond.

bioinformatics↗

bioRxiv2025

Cerebral Organoids Uncover Mechanisms of Neural Activity Changes in Epileptogenesis

Neurological disorders often originate from progressive brain network dysfunctions that start years before symptoms appear. How these changes emerge in the developing human brain remains elusive due to a lack of tractable model systems. Here, we show a cerebral organoid model of Tuberous Sclerosis Complex (TSC) that recapitulates hallmarks of epileptogenesis in vitro. We compare extracellular recordings of TSC organoids with intraoperative electrocorticography from TSC patients to reveal striking functional similarities, including high-frequency oscillations - an electrical biomarker for epileptogenic tissue. In TSC, a human-specific interneuron sub-type derived from the caudal ganglionic eminence drives network hyper-synchronization through increased spontaneous firing and altered excitability. Inhibiting overproliferation of its progenitors via long-term epidermal growth factor receptor inhibition prevented the onset of this pathological phenotype at functional and morphological levels. Our work shows that organoids allow mechanistic analysis of emerging neural network phenotypes, enabling anti-epileptogenic drug testing in a human brain development model.

neuroscience↗

bioRxiv2022

Multi-chamber cardioids unravel human heart development and cardiac defects

The number one cause of human fetal death are defects in heart development. Because the human embryonic heart is inaccessible, and the impacts of mutations, drugs, and environmental factors on the specialized functions of different heart compartments are not captured by in vitro models, determining the underlying causes is difficult. Here, we established a human cardioid platform that recapitulates the development of all major embryonic heart compartments, including right and left ventricles, atria, outflow tract, and atrioventricular canal. By leveraging both 2D and 3D differentiation, we efficiently generated progenitor subsets with distinct first, anterior, and posterior second heart field identities. This advance enabled the reproducible generation of cardioids with compartment-specific in vivo-like gene expression profiles, morphologies, and functions. We used this platform to unravel the ontogeny of signal and contraction propagation between interacting heart chambers and dissect how genetic and environmental factors cause region-specific defects in the developing human heart. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=155 SRC="FIGDIR/small/499699v1_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@c9c629org.highwire.dtl.DTLVardef@f0d521org.highwire.dtl.DTLVardef@1389411org.highwire.dtl.DTLVardef@181098a_HPS_FORMAT_FIGEXP M_FIG C_FIG HIGHLIGHTS- Mesoderm induction and patterning signals specify aSHF, pSHF, and FHF progenitors - Cardiac progenitors sort, co-develop and functionally connect in multi-chamber cardioids - Multi-chamber cardioids coordinate contraction propagation and share a lumen - Multi-chamber platform dissects genetic (ISL1, TBX5, FOXF1) and teratogenic defects

developmental biology↗

bioRxiv2018

Broad applicability of a streamlined Ethyl Cinnamate-based clearing procedure

Turbidity and opaqueness are inherent properties of tissues which limit the capacity to acquire microscopic images through large tissues. Creating a uniform refractive index, known as tissue clearing, overcomes most of these issues. These methods have enabled researchers to image large and complex 3D structures with unprecedented depth and resolution. However, tissue clearing has been adopted to a limited extent due to a combination of cost, time, complexity of existing methods and potential negative impact on fluorescence signal. Here we describe 2Eci (2nd generation Ethyl cinnamate based clearing method) which can be used to clear a wide range of tissues, including cerebral organoids, Drosophila melanogaster, zebrafish, axolotl, and Xenopus laevis in as little as 1-5 days while preserving a broad range of fluorescence proteins including GFP, mCherry, Brainbow, and alexa-fluorophores. Ethyl cinnamate is non-toxic and can easily be used in multi-user microscope facilities. This method will open up clearing to a much broader group of researchers, due to its broad applicability, ease of use, and non-toxic nature of Ethyl cinnamate.\n\nSummary statementThe non-toxic, broadly applicable, and simplified protocol of 2Eci tissue clearing makes it possible for non-specialist labs to use clearing approaches on conventional inverted microscopes.

developmental biology↗

bioRxiv2017

Fused dorsal-ventral cerebral organoids model human cortical interneuron migration

Development of the forebrain involves the migration of GABAergic interneurons over long distances from ventral into dorsal regions. Although defects in interneuron migration are implicated in neuropsychiatric diseases such as Epilepsy, Autism, and Schizophrenia, model systems to study this process in humans are currently lacking. Here, we describe a method for analyzing human interneuron migration using 3D organoid culture. By fusing cerebral organoids specified toward dorsal and ventral forebrain, we generate a continuous dorsal-ventral axis. Using fluorescent reporters, we demonstrate robust directional GABAergic interneuron migration from ventral into dorsal forebrain. We describe methodology for time lapse imaging of human interneuron migration that is inhibited by the CXCR4 antagonist AMD3100. Our results demonstrate that cerebral organoid fusion cultures can model complex interactions between different brain regions. Combined with reprogramming technology, fusions offer a possibility to analyze complex neurodevelopmental defects using cells from neuropsychiatric disease patients, and to test potential therapeutic compounds.

neuroscience↗