Assessing the mechanical energy costs of various tissue reshaping mechanisms

摘要: Early-stage embryos must reshape the tissues of which they are made into organs and other life-sustaining structures; if non-mammalian fail to complete these tasks before energy provided by their yolk runs out, die. The aim this study is use a cell-level computational model investigate energetic cost variety mechanisms that can drive an in-plane reshaping pattern known as convergent extension—a motif in tissue narrows one direction expands another. Mechanisms considered include oriented lamellipodia, directed mitosis, stress fibers, anisotropic external tension. Both isolated patches actively contracting deform adjacent passive areas considered. finite element used here assumes cell membrane its associated proteins generate net tension γ along each cell–cell interface cytoplasm embedded networks structures have effective viscosity μ. Work costs based exclusively on mechanical considerations such edge lengths tensions, because traditional efficiency cannot be calculated, compared basis work do cause specified rate reshaping. Although contains number simplifications real embryonic tissues, it able show requirements for mitoses lamellipodia same order. Lamellipodia energetically most when tensions approximately twice large interfacial surrounding cells. also shows fibers or direct stretch compression at least five times more efficient than needed typical cellular thirty greater did not contain boundaries. Collectively, findings indicate common efficiencies less percent primary determinant mechanism(s) embryo uses tissues.