Crisscross multilayering of cell sheets

Abstract

Hydrostatic skeletons such as the Hydra’s consist of two stacked layers of muscle cells perpendicularly oriented. In vivo, these bilayers first assemble, and then the muscle fibers of both layers develop and organize with this crisscross orientation. In the present work, we identify an alternative mechanism of crisscross bilayering of myoblasts in vitro, which results from the prior local organization of these active cells in the initial monolayer. The myoblast sheet can be described as a contractile active nematic in which, as expected, most of the +1/2 topological defects associated with this nematic order self-propel. However, as a result of the production of extracellular matrix by the cells, a subpopulation of these comet-like defects does not show any self-propulsion. Perpendicular bilayering occurs at these stationary defects. Cells located at the head of these defects converge toward their core where they accumulate until they start migrating on top of the tail of the first layer, while the tail cells migrate in the opposite direction under the head. Since the cells keep their initial orientations, the two stacked layers end up perpendicularly oriented. This concerted process leading to a crisscross bilayering is mediated by the secretion of extracellular matrix.

Geometric confinement guides topological defect pairings and emergent flow in nematic cell populations

“…This phenomenon may be due to the tendency of C2C12 cells to form multi-layered structures instead of monolayers as the confinement size decreases. 40,55 Incorporating compressive force exerted by surface-contracted cells into the theory of nematic elasticity remains a future challenge. Furthermore, we have demonstrated that the deformation of the cell nucleus was induced by establishing geometry-induced alignment of cells in the vicinity of tip regions where the cells undergo significant orientation change in the doublet and triplet circle boundaries.…”

“…A recent study indicated the deformation of the cell nucleus also plays a role in controlling cell differentiation, such as mechanochemical signaling. 48 Because C2C12 cells fuse into myotubes through differentiation induction, 40,41,55 stretching of the nucleus under our designed geometric confinements could offer insights into the mechanism of force-induced morphogenesis.…”

Physiological ramifications of constrained collective cell migration

“…[ 32 ] In vitro, it has recently been suggested that the geometry of the deposited ECM can determine the orientational field of a myoblast monolayer, creating zones of cell accumulation and multilayering. [ 33 ]…”

Aging and freezing of active nematic dynamics of cancer-associated fibroblasts by fibronectin matrix remodeling

“…To investigate whether CAFs exhibit nematic ordering similar to other elongated cells, such as myoblasts [24][25][26] , we seeded CAFs isolated from human colorectal tumors on 11 kPa polyacrylamide (PAA) gels coated with monomeric collagen I to maintain physiological substrate rigidity 27 . Over time, CAFs established a monolayer, comprising large regions of aligned cells forming nematic order (Fig.…”