bioRxiv Science⌕ Search

Biology subjects

Stenzel, M.

Publications and source records attributed to Stenzel, M..

5 recordsLinked to original sources

Engineered 3D hydrogel model reveals divergence of adhesion-migration balance in Glioblastoma under simulated microgravity

Glioblastoma is an aggressive brain cancer whose cells can switch between different modes of invasion in response to their surroundings, making the disease difficult to predict and treat. How physical forces influence this adaptability remains poorly understood. Here, we used simulated microgravity together with engineered hydrogels that independently control adhesion, degradability, and mechanical properties to test how gravity affects glioblastoma invasion. Microgravity strongly reduced invasion and shifted cells from elongated, protrusive behavior to a more cohesive state. Proteomic analysis showed reduced invasive signaling together with increased cell-matrix and cell-cell adhesion, consistent with a redistribution of contractile forces toward the cell edge. Under normal gravity, blocking CD44, integrin {beta}1, or N-cadherin reduced matrix-dependent invasion. In contrast, under microgravity, inhibiting these same adhesion pathways restored invasion, indicating that microgravity traps cells in an overly adhesive, cohesive state that limits movement rather than motility itself. These findings show that gravity is an important regulator of cancer cell plasticity and reveal a mechanically induced vulnerability in glioblastoma invasion. More broadly, combining defined biomaterials with gravitational modulation provides a new way to study how physical forces shape tumor behavior.

cancer biology↗

Leonardo: a toolset to correct sample-induced artifacts in light sheet microscopy images

Selective plane illumination microscopy (SPIM, also known as light sheet fluorescence microscopy) is the method of choice for studying morphogenesis and function in biological specimens over extended periods, as it permits gentle and rapid volumetric imaging. In inhomogeneous samples, however, sample-induced artifacts, including light absorption, scattering, and refraction, can impact the image quality, particularly as the focal plane gets deeper into the sample. Here, we present Leonardo, the first toolbox designed to address the major sample-induced artifacts by using two modules: (1) DeStripe removes stripe artifacts in SPIM caused by light absorption while preserving fine sample structures; (2) Fuse reconstructs a single high-quality image from dualsided illumination and/or dual-sided detection, while eliminating blur and optical distortions caused by light scattering and refraction. The efficacy of Leonardo is validated on a wide range of biological samples, from minimally invasive experiments on sensitive specimens (translucent embryonic and optically opaque larval zebrafish) to cleared mouse samples up to two centimeters in size. We provide model code and a Napari-based graphical user interface, enabling the SPIM community to easily apply Leonardo to advance light sheet imaging of inhomogeneous and complex specimens.

bioinformatics↗

A COVID-19 Rapid Antigen Test Employing Upconversion Nanoparticles

The COVID-19 pandemic has underscored the critical need for rapid and accurate diagnostic tools. Current methods, including PCR and rapid antigen tests (RAT), have limitations in speed, sensitivity, and the requirement for specialized equipment and trained personnel. Nanotechnology, particularly upconversion nanoparticles (UCNPs), offer a promising alternative due to their unique optical properties. UCNPs can convert low-energy near-infrared (NIR) light into higher-energy visible light, making them ideal for use as optical probes in single molecule detection and point of care applications. This study, initiated in early 2020, explores the opportunity of using highly doped UCNPs (40%Yb3+/4%Er3+) in lateral flow assay (LFA) for the early diagnosis of COVID-19. The UCNPs-based LFA testing demonstrated a minimum detection concentration of 100 pg/mL for SARS-CoV-2 antigen and 105 CCID50/mL for inactivated virus. Clinical trials, conducted in Malaysia and Western Australia independently, showed that the technique was at least 100 times more sensitive than commercial RAT kits, with a sensitivity of 100% and specificity of 91.34%. The development process involved multidisciplinary collaborations, resulting in the Virulizer device, an automated strip reader for point-of-care testing. This work sets a reference for future development of highly sensitive and quantitative rapid antigen tests, aiming for the Limits of Detection (LoD) in the range of sub-ng/mL.

bioengineering↗

Peyers Patch B cells undergo cell death via neutrophil-released toxic DNA following sterile tissue injury

Lymphocyte contraction (LC) in central immune organs is a concomitant of sterile tissue injury, for example after stroke. Intestinal Peyers patches (PP) harbor large numbers of B cells, but how sterile tissue injury leads to LC in PP has not been explored. We observed rapid and macroscopically evident shrinkage of PP after stroke and myocardial infarction. Light-sheet fluorescence microscopy and flow cytometry revealed a strong reduction in the number of PP-resident B cells. Mechanistically, tissue injury triggered the activation of neutrophils that released B cell-toxic neutrophil extracellular traps (NETs) decorated with citrullinated histone-H3. Antibody-mediated or genetically induced neutrophil-loss, NETs-degradation or blockade of their generation completely reversed B cell loss and preserved the tissue architecture of PP. We also found NET-like elements in human post-stroke plasma. Hence, we propose that targeting NET-generation or -function counteracts post-injury B cell contraction in PP and thereby maintains immune homeostasis at mucosal barriers. In briefHigh numbers of B cells reside in the intestinal Peyers patches. Tuz et al. revealed that in response to sterile tissue injury, activated neutrophils release histone-decorated DNA into the circulation which induces B cell death. The loss of B cells results in the shrinkage of Peyers patches and reduced amounts of secretory IgA. HighlightsO_LIStroke and myocardial infarction induce the melting of Peyers patch C_LIO_LILight-sheet microscopy and cytometry revealed B cell loss in Peyers patch C_LIO_LIPost-injury activated neutrophils release NETs and trigger B cell death C_LIO_LIInhibition of NETs rescues B cell loss and degeneration of Peyers patch C_LI

immunology↗

Quantitatively Monitoring in situ Mitochondrial Thermal Dynamics by Upconversion Nanoparticles

Temperature dynamics reflect the physiological conditions of cells and organisms. Mitochondria regulates temperature dynamics in living cells, as they oxidize the respiratory substrates and synthesize ATP, with heat being released as a by-product of active metabolism. Here, we report an upconversion nanoparticles based thermometer that allows in situ thermal dynamics monitoring of mitochondria in living cells. We demonstrate that the upconversion nanothermometers can efficiently target mitochondria and the temperature responsive feature is independent of probe concentration and medium conditions. The relative sensing sensitivity of 3.2% K-1 in HeLa cells allows us to measure the mitochondrial temperature difference through the stimulations of high glucose, lipid, Ca2+ shock and the inhibitor of oxidative phosphorylation. Moreover, cells display distinct response time and thermal dynamic profiles under different stimulations, which highlights the potential applications of this thermometer to study in situ vital processes related to mitochondrial metabolism pathways and interactions between organelles.

cell biology↗