Biology subjects

Serweta, A. K.

Publications and source records attributed to Serweta, A. K..

3 recordsLinked to original sources

bioRxiv2026

Multiscale three-dimensional ultrastructural mapping of intestinal tissues and organoids

Understanding cell biology in native environments requires imaging of subcellular organization in three dimensions. In the intestinal epithelium, multiple cell types organize along the crypt-villus axis, where cell-cell interfaces and subcellular architecture control cell differentiation, tissue organization and epithelial function. Resolving these features volumetrically remains challenging: light microscopy offers molecular specificity but has limited resolution, whereas electron microscopy provides ultrastructural detail but is poorly suited to volumetric acquisition combined with specific protein labeling. Here, we show that expansion microscopy enables the multiscale volumetric study of epithelial ultrastructure in tissue sections and organoid models. Using an optimized workflow, we resolve epithelial tissue architecture, cell types and subcellular features within volumes across scales. Application to a microvillus inclusion disease (MVID) organoid model revealed disease-associated ultrastructural phenotypes that were only observed using electron microscopy. Our results establish expansion microscopy as key technology for studying three-dimensional cell biology within intestinal tissue and tissue mimics.

cell biology↗

bioRxiv2025

Polarity reversal of stable microtubules during neuronal development

Neurons critically depend on long-distance transport orchestrated by motor proteins walking over their highly asymmetric microtubule cytoskeleton. These microtubules are organized uniformly in axons with their plus-end pointing away from the soma. In contrast, in the dendrites of vertebrate neurons, microtubules are of mixed polarity, but organized into bundles of uniform polarity with stable, long-lived microtubules preferentially oriented minus-end-out and dynamic microtubules oriented plus-end-out. This organization is thought to be essential for guiding selective transport into dendrites, yet how this organization is established is unclear. Here we use a combination of single molecule localization microscopy, expansion microscopy, and live-cell imaging to examine how the microtubule cytoskeleton is reorganized during neuronal development of cultured rat hippocampal neurons. We find that, while the youngest neurites contain microtubules of mixed polarity, stable microtubules are initially preferentially oriented plus-end-out. At this stage of development many stable microtubules are connected to the centrioles, providing an explanation for their plus-end out orientation in emerging neurites. In later stages, these microtubules are released from the centrioles and reorient by sliding between or within neurites to become progressively more minus-end-out. Moreover, prior to axon specification, we commonly observed already one or two minor neurites with an almost uniformly plus-end-out microtubule network, indicative of transient polarization. Together, our findings reveal how stable microtubules are reorganized to help establish the stereotypical microtubule networks seen in the axon and dendrites of mature vertebrate neurons.

cell biology↗

bioRxiv2022

GelMap: Intrinsic calibration and deformation mapping for expansion microscopy

Expansion microscopy (ExM) is a powerful technique to overcome the diffraction limit of light microscopy by physically expanding biological specimen in three dimensions. Nonetheless, using ExM for quantitative or diagnostic applications requires robust quality control methods to precisely determine expansion factors and to map deformations due to anisotropic expansion. Here we present GelMap, a flexible workflow to introduce a fluorescent grid into pre-expanded hydrogels that scales with expansion and reports deformations. We demonstrate that GelMap can be used to precisely determine the local expansion factor and to correct for deformations without the use of cellular reference structures or pre-expansion ground truth images. Moreover, we show that GelMap aids sample navigation for correlative uses of expansion microscopy. Finally, we show that GelMap is compatible with expansion of tissue and can be readily implemented as a quality control step into existing ExM workflows.

cell biology↗