Berlin 2024 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

BP: Fachverband Biologische Physik

BP 33: Focus session: Physics of organoids

BP 33.2: Vortrag

Donnerstag, 21. März 2024, 15:30–15:45, H 1028

Mechanisms of pattern formation and self-organization in embryonic organoids — •Valentin Dunsing-Eichenauer, Alice Gros, Sham Tlili, Jules Vanaret, Leo Guignard, and Pierre-François Lenne — IBDM & CENTURI, Aix-Marseille University/ CNRS, Marseille, France

The emergence of asymmetries within a mass of equivalent cells is a key event in embryonic development, resulting in formation of the main body axes. We investigate symmetry breaking in gastruloids, an in vitro model of early mammalian embryogenesis. Upon Wnt activation, polarized gene expression patterns emerge from an initially homogenous state, followed by elongation and formation of germ-layer-like tissues. Interestingly, robust symmetry breaking occurs only in aggregates of a certain size, smaller or larger aggregates do not polarize. To understand this phenomenon, we investigate the underlying patterning mechanism. To this aim, we have developed a quantitative imaging pipeline using in toto 2-photon imaging and deep learning based cell segmentation. For aggregates of different size, we quantify i) overall shape, ii) coarse grained spatiotemporal distribution of differentiation, iii) relative proportions of emerging heterogenous cell populations. Our results indicate that cell differentiation emerges first in outer and subsequently propagates to inner cell layers. Concomitantly, the initially continuous adhesion protein network fragments and cells sort into different domains. We next plan to incorporate these findings into a cell-based model to test whether such propagation mechanism and fluctuations in aggregate shape are sufficient to break symmetry.

Keywords: Self-organization; Cell dynamics; Bioimaging; Fluorescence Microscopy; Image Analysis