Biology subjects

Vangheel, J.

Publications and source records attributed to Vangheel, J..

8 recordsLinked to original sources

bioRxiv2026

Cellular timing heterogeneity regulates phase transitions in living matter

Rigidity transitions govern tissue organization in ways reminiscent of inert materials. Yet, living tissues are composed of active units with autonomous timing mechanisms, raising the question whether microscopic cellular timing distribution influences collective mechanical states. Here we identify heterogeneity in cellular timescales as a heritable parameter, regulating rigidity transitions in embryonic tissues. Lineage tracking and quantitative mechanical analysis reveal that zebrafish morphogenesis starts with a tissue rigidity collapse occurring at maximal cell cycle length heterogeneity. This heterogeneity arises from size-dependent stochastic differences in resource allocation, with resource availability defining the cell cycle length. Such differences are inherited across generations, amplifying and structuring tissue-wide cell cycle length heterogeneity. Experiments and large-scale 3D simulations identify an optimum level of cellular timing variability at which cell-cell contact remodelling is spatially coordinated driving timely and robustly the rigidity transition. These findings demonstrate that embryos exploit microscopic temporal disorder for timing and tuning tissue morphogenesis.

biophysics↗

bioRxiv2026

Integrated quantitative imaging and biomechanical modeling of early gastrulation in C. elegans

1The stereotyped internalization of two endodermal precursors during early Caenorhabditis elegans gastrulation enables quantitative dissection of cell ingression mechanics. Experimental work has shown that apical constriction drives Ea and Ep ingression, and several molecular features involved have been identified. Yet, no integrative mechanical analysis has assessed how these elements collectively produce the observed behavior. To address this, we combined biomechanical simulations with a comprehensive dataset of 3D-segmented cell meshes, some with cortical protein distributions, to analyze the mechanics of ingression in its in-vivo context. Our analysis shows the process starts shortly after birth of the ingressing cells. A cortical flow drives the formation of an E-cadherin-rich structure at the apical Ea-Ep interface, which contributes to localizing the buildup of apical tension. Simulations show that medioapical actomyosin contraction can reproduce the observed ingression movements and suggest force transmission to neighboring cells via a friction-based molecular clutch at the apical ring of contact. A series of concurrent cell divisions facilitates ingression, and their stereotyped planar orientation also contributes. Furthermore, we observe an embryo-wide movement of cells during gastrulation. This movement resembles a flow, suggesting that local force generation leads to global rearrangements via internal pressure changes. Finally, at the end of ingression, detailed microscopy shows that neighboring cells actively close the gastrulation cleft by forming a rosette-like configuration and extending actin-rich protrusions. In conclusion, our integrated mechanical description of gastrulation shows that successful ingression is driven by apical constriction and supported by localized friction-based force transmission, coordinated stereotyped cell divisions, and the resulting global tissue flow.

developmental biology↗

bioRxiv2026

Nematic structures contribute to robust zygotic polarization in C. elegans

The C. elegans zygote is a powerful model for asymmetric cell division. Its strikingly patterned cortex features thick F-actin bundles and myosin foci, contractile nematic structures that drive characteristic surface ruffles. Early in the cell cycle, symmetry breaks near the sperm-contributed centrosomes, typically at the presumptive posterior pole, and is marked by local downregulation of contractility. This initiates a cortical flow that polarizes the cell and enables PAR proteins to establish anterior and posterior domains. While biochemical mechanisms maintaining these domains are well understood, the mechanical role of cortical architecture in polarization remains unclear. We developed a three-dimensional (3D) mechanical model of C. elegans zygote polarization that represents the actin bundles and myosin foci of the cortex as a network of stiff contractile filaments. We measured cortical flow with high spatiotemporal resolution by tracking myosin foci, and used these data alongside mechanical properties from the literature to parametrize the model. The model simulates the complete polarization process in 3D, from symmetry breaking through domain stabilization, and reproduces key cortical dynamics including flow profiles, surface ruffles, and tension anisotropy. Domain arrest near the embryo midpoint emerges from density-dependent contractility regulation, in which cortical material redistribution during flow creates a mechanical negative feedback that balances anterior and posterior tension.We find that compressive flow aligns actin bundles in the anterior domain and generates anisotropic tension perpendicular to the flow direction. Although this alignment is not essential for polarization when symmetry breaking occurs at the pole, it contributes to this process when symmetry breaking occurs laterally. In such cases, anisotropic tension from aligned bundles drives axis convergence by rotating the posterior domain towards the nearest pole. Nematic cortical structures therefore ensure robust alignment of the polarization axis. AvailabilityAll data and code required to reproduce the results are freely available at https://doi.org/10.5281/zenodo.18135771. The latest version of the software is maintained at https://bitbucket.org/pgmsembryogenesis/polarization.

developmental biology↗

bioRxiv2025

Stress-dependent growth of breast cancer models emerges from a cellular volume checkpoint

Mechanoresponsive cell proliferation is a feature of growing tumours, despite the suppression of many other regulatory checkpoints in cancer, but the underlying cell-scale mechanisms driving this behaviour have not yet been established. In this study we propose a biophysical model for cell growth as governed by actively controlled osmolarity, which we integrate with a discrete particle framework to simulate growth and remodelling of breast cancer spheroids. Confinement and biomechanical feedback from the extracellular environment are analysed through a neuralnetwork-accelerated finite element solver. Combining the framework with experiments, our model reveals that stress-dependent spheroid growth can arise from a sizing checkpoint for mitosis. Under sufficient extracellular loading, cell growth is restricted by high hydrostatic forces in competition with osmotic pressure from biomolecule synthesis, which prevents cells from surpassing a critical volume. Our model provides new insight into mechanosensitive growth arrest in breast cancer, potentially serving as a computational tool for analysing growth in a wider range of normal and malignant biological tissues.

cancer biology↗

bioRxiv2025

Rigidity transitions in a 3D active foam model of cell monolayers with frictional contact interactions

In morphogenesis and disease, biological tissues may exhibit diverse mechanical properties due to their capacity to switch between fluid-like to solid-like states through the (un)jamming transition. Here, we introduce a novel foam model to investigate how active mechanical properties and cellular interactions govern this transition in active cell monolayers. This model explicitly represents 3D cell shapes and describes cell-cell interactions via discrete interacting surfaces. Simulations reveal that cell-cell adhesive tension promotes tissue fluidization in high adhesive tissues, where it mainly promotes cell deformability, while it induces solidification in the low adhesive regime, where it prevents cell-cell debonding. Moreover, we study the dynamic role of adhesive ligand turnover through an effective intercellular friction. Through simulated shear experiments, we find that intercellular friction strongly suppresses neighbor exchanges, but does not lead to solid-like tissue properties. We discuss the implications of our results for understanding the relationship between unjamming and partial epithelial-mesenchymal transition, highlighting how differences in adhesion dynamics and intercellular friction may reconcile conflicting observations in tissue mechanics and cancer metastasis.

biophysics↗

bioRxiv2024

Active foam dynamics of tissue spheroid fusion

Three-dimensional tissue spheroids are a key building block in biofabrication, yet the link between their material properties and active mechanics of individual cells is not fully understood. We study the material properties of small spheroids of human periosteum-derived cells as they effect spheroid fusion, an elementary operation for constructing large tissue structures. We use two-photon confocal microscopy to measure cell-cell tension and individual cell motility throughout fusion. Cytoskeletal inhibition through Y-27632 (ROCKi) results in more granular tissues with decreased cell rearrangements, but accelerated fusion. Further reducing cell contractility with blebbistatin and ROCKi increases tissue granularity, decreases rearrangements, and slows down fusion. In all conditions, complete fusion is associated with frequent cellular rearrangements. Using a novel computational model that represents tissue material as an active cellular foam, with cells depicted as viscous shells with interfacial tension and persistent, random motility, we construct a phase diagram of spheroid fusion in function of relative cell-cell tension and cell motility. Our results reveal a close relationship between microscopic tissue fluidity and the visco-elastic properties of spheroid fusion. Additionally, we find that cell-cell friction promotes arrested fusion by inducing jamming through a distinct physical mechanism. Combined, our findings offer a framework for understanding spheroid fusion dynamics that can aid in the robust generation of large tissue constructs for regenerative medicine.

biophysics↗

bioRxiv2023

Image-based force inference by biomechanical simulation

During morphogenesis, cells precisely generate forces that drive cell shape changes and cellular motion. These forces predominantly arise from contractility of the actomyosin cortex, allowing for cortical tension, protrusion formation, and cell division. Image-based force inference can derive such forces from microscopy images, without complicated and time-consuming experimental set-ups. However, current methods do not account for common effects, such as physical confinement and local force generation. Here we propose a force-inference method based on a biophysical model of cell shape, and assess relative cellular surface tension, adhesive tension between cells, as well as cytokinesis and protrusion formation. We applied our method on fluorescent microscopy images of the early C. elegans embryo. Predictions for cell surface tension at the 7-cell stage were validated by measurements using cortical laser ablation. Our non-invasive method facilitates the accurate tracking of force generation, and offers many new perspectives for studying morphogenesis. Author summaryAn important challenge in understanding morphogenesis is to determine where forces are generated. Force generation, such as differential cortical tension, plays a key role in cellular self-organization. However, measuring these forces experimentally is a big challenge that typically requires complicated experiments and direct access to the cells being investigated. A non-invasive method, such as force inference based on cell shapes, would have important advantages. Unfortunately, current methods can only be applied in certain cases. Here, we describe a more flexible 3D force inference method, FIDES, that can account for physical confinement, cell divisions and protrusions. We applied the method to infer forces throughout early C. elegans embryogenesis. By using cortical laser ablations, we confirmed that FIDES correctly inferred cell surface tensions in a dynamic stage of the nematodes embryogenesis. Our approach offers a route to routinely infer force generation in complex movements during morphogenesis, with microscopy images of cell shapes as the sole experimental input.

bioinformatics↗

bioRxiv2021

Activity-induced fluidization of arrested coalescence in fusion of cellular aggregates

At long time scales, tissue spheroids may flow or appear solid depending on their capacity to reorganize their internal structure. Understanding the relationship between intrinsic mechanical properties at the single cell level, and the tissue spheroids dynamics at the long-time scale is key for artificial tissue constructs, which are assembled from multiple tissue spheroids that over time fuse to form coherent structures. The dynamics of this fusion process are frequently analyzed in the framework of liquid theory, wherein the time scale of coalescence of two droplets is governed by its radius, viscosity and surface tension. In this work, we extend this framework to glassy or jammed cell behavior which can be observed in spheroid fusion. Using simulations of an individual-cell based model, we demonstrate how the spheroid fusion process can be steered from liquid to arrested by varying active cell motility and repulsive energy as established by cortical tension. The divergence of visco-elastic relaxation times indicates glassy relaxation near the transition towards arrested coalescence. Finally, we investigate the role of cell growth in spheroid fusion dynamics. We show that the presence of cell division introduces plasticity in the material and thereby increases coalescence during fusion.

biophysics↗