Cell condensation initiates organogenesis: the role of actin dynamics in supracellular self-organizing process

The emergence of complex tissue architectures from homogeneous stem cell condensates persists as a central enigma in developmental biology. While biochemical signaling gradients have long dominated explanations of organ patterning, the mechanistic interplay between tissue-scale forces and thermodynamic constraints in driving symmetry breaking remains unresolved. This review unveils supracellular actin networks as mechanochemical integrators that establish developmental tensegrity structures, wherein Brownian ratchet-driven polymerization generates patterned stress fields to guide condensate stratification. Central to this paradigm is the dynamic remodeling of actin branches, which transduce mechanical loads into adaptive network architectures through force-modulated capping kinetics and angular reorientation. Such plasticity enables fluid-to-solid phase transitions, stabilizing organ primordia through viscoelastic microdomain formation. Crucially, these biophysical processes are functionally coupled with metabolic reprogramming events, where cytoskeletal strain modulates glycolytic flux and nuclear mechanotransduction pathways to inform differentiation decisions, forging a feedback loop between tissue mechanics and cellular fate specification. Building on these insights, we argue that limitations in current organoid self-organization may originate from incomplete reconstitution of actin-mediated mechanical coherence, and modeling of heterogeneous mesenchymal condensation dynamics offers a strategic framework to decode self-organization trajectories, bridging developmental principles with regenerative design. By synthesizing advances from molecular biophysics to tissue mechanics, this work reframes organogenesis not as a hierarchy of molecular commands, but as an emergent continuum where biochemical, mechanical, and thermodynamic constraints coevolve to sculpt living architectures.