Mechanics of compression-driven morphogenesis.

Mechanical forces shape multiscale biological processes across many living systems, ranging from cell proliferation and apoptosis, to tissue folding and pattern formation. In recent years, tissue pressure has emerged as a fundamental regulator of morphogenesis across animal and plant kingdoms. However, a fundamental understanding of the definition and origin of tissue pressure remains lacking. In this Review, we synthesise how tissue pressure is generated from diverse sources, including tissue growth, actomyosin contractility, topological defects and fluid- or extracellular matrix-driven swelling, and how it influences developmental processes such as proliferation, apoptosis, differentiation, tissue folding and pattern formation. We also discuss how homeostatic pressure governs tissue growth and competition, while highlighting the cellular and molecular signalling pathways implicated in compressive stress responses. Finally, drawing on examples from animal, plant, bacterial and organoid systems, we outline emerging experimental and computational approaches to measure and manipulate tissue pressure in vivo, and identify key challenges in dissecting compression-specific mechanosignalling pathways.