Quantitative cell migration in 3D compliant hydrogel microenvironments

Stöberl, Stefan (2024): Quantitative cell migration in 3D compliant hydrogel microenvironments. Dissertation, LMU München: Fakultät für Physik

Abstract

Cell migration is a key process in various physiological settings, including immune responses, wound healing, and cancer metastasis. In these contexts, cells navigate through narrow constrictions within the extracellular matrix (ECM). In active soft matter models, the migration across barriers is under debate. In particular the role of the cell nucleus, as a large and stiff organelle, has received increasing attention as a rate-limiting factor in confined cell migration. Previous studies have shown that cells can be guided by micro-patterned surfaces. The dynamics of cells in 2D dumbbell pattern is well captured by inferred equations of motion. However, under physiological conditions, cells typically migrate in 3D physical confinement. This prompts ongoing discussions regarding the dynamics in 3D pattern and the mechanisms by which cells regulate their nuclear properties and force generation machinery to overcome spatial constrictions. In this thesis, we utilized photo-lithographic microfabrication techniques to cast artificial experimental platforms for the study of cell migration in confinement. In a first study, we generated hydrogel-hydrogel interfaces, termed ’sponge clamps’, to investigate cell invasion dynamics between deformable walls. Our results revealed notable differences in the invasion velocity of cancerous cell lines as a function of gap size and the stiffness of the hydrogel. In a next attempt, we fabricated dumbbellshaped cavities to study repeated cell migration across 3D-constrictions with defined widths. We collected statistics from hundreds of cell trajectories in arrayed dumbbells and observed that in wider channels, both the rates of transition and nuclear velocities increase with confinement, while migration is impeded for subnuclear confinement. To further elucidate the mechanical aspects of the nucleus’s role as a limiting factor in confined cell migration, we assessed the elastic modulus and the shape deformation of the nucleus within the dumbbell-shaped cavities. We discovered both transient deformation into oblate as well as prolate shapes along with nuclear volume reductions during transmigration as determined by confocal microscopy. Additionally, we evaluated the forces exerted by the nucleus onto compliant hydrogel walls using displacement fields of embedded marker beads. The measured nuclear morphology as a function of confinement presented the basis for a theoretical model developed by the Broedersz group. The analysis yielded a quantitative assessment of the balance between pulling and pushing forces and suggest a cellular force generation adaptation in response to confinement. Overall, our findings highlight the efficacy and versatility of 3D-microfabricated cell migrations assays utilizing soft hydrogel architectures for the study of cell mechanics.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Themengebiete: 500 Naturwissenschaften und Mathematik ; 500 Naturwissenschaften und Mathematik > 530 Physik
• Fakultäten: Fakultät für Physik
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 9. Juli 2024
• 1. Bericht­erstatter:in: Rädler, Joachim