@article{9629, abstract = {Intestinal organoids derived from single cells undergo complex crypt–villus patterning and morphogenesis. However, the nature and coordination of the underlying forces remains poorly characterized. Here, using light-sheet microscopy and large-scale imaging quantification, we demonstrate that crypt formation coincides with a stark reduction in lumen volume. We develop a 3D biophysical model to computationally screen different mechanical scenarios of crypt morphogenesis. Combining this with live-imaging data and multiple mechanical perturbations, we show that actomyosin-driven crypt apical contraction and villus basal tension work synergistically with lumen volume reduction to drive crypt morphogenesis, and demonstrate the existence of a critical point in differential tensions above which crypt morphology becomes robust to volume changes. Finally, we identified a sodium/glucose cotransporter that is specific to differentiated enterocytes that modulates lumen volume reduction through cell swelling in the villus region. Together, our study uncovers the cellular basis of how cell fate modulates osmotic and actomyosin forces to coordinate robust morphogenesis.}, author = {Yang, Qiutan and Xue, Shi-lei and Chan, Chii Jou and Rempfler, Markus and Vischi, Dario and Maurer-Gutierrez, Francisca and Hiiragi, Takashi and Hannezo, Edouard B and Liberali, Prisca}, issn = {1476-4679}, journal = {Nature Cell Biology}, pages = {733–744}, publisher = {Springer Nature}, title = {{Cell fate coordinates mechano-osmotic forces in intestinal crypt formation}}, doi = {10.1038/s41556-021-00700-2}, volume = {23}, year = {2021}, } @article{10365, abstract = {The early development of many organisms involves the folding of cell monolayers, but this behaviour is difficult to reproduce in vitro; therefore, both mechanistic causes and effects of local curvature remain unclear. Here we study epithelial cell monolayers on corrugated hydrogels engineered into wavy patterns, examining how concave and convex curvatures affect cellular and nuclear shape. We find that substrate curvature affects monolayer thickness, which is larger in valleys than crests. We show that this feature generically arises in a vertex model, leading to the hypothesis that cells may sense curvature by modifying the thickness of the tissue. We find that local curvature also affects nuclear morphology and positioning, which we explain by extending the vertex model to take into account membrane–nucleus interactions, encoding thickness modulation in changes to nuclear deformation and position. We propose that curvature governs the spatial distribution of yes-associated proteins via nuclear shape and density changes. We show that curvature also induces significant variations in lamins, chromatin condensation and cell proliferation rate in folded epithelial tissues. Together, this work identifies active cell mechanics and nuclear mechanoadaptation as the key players of the mechanistic regulation of epithelia to substrate curvature.}, author = {Luciano, Marine and Xue, Shi-lei and De Vos, Winnok H. and Redondo-Morata, Lorena and Surin, Mathieu and Lafont, Frank and Hannezo, Edouard B and Gabriele, Sylvain}, issn = {1745-2481}, journal = {Nature Physics}, number = {12}, pages = {1382–1390}, publisher = {Springer Nature}, title = {{Cell monolayers sense curvature by exploiting active mechanics and nuclear mechanoadaptation}}, doi = {10.1038/s41567-021-01374-1}, volume = {17}, year = {2021}, } @article{6508, abstract = {Segregation of maternal determinants within the oocyte constitutes the first step in embryo patterning. In zebrafish oocytes, extensive ooplasmic streaming leads to the segregation of ooplasm from yolk granules along the animal-vegetal axis of the oocyte. Here, we show that this process does not rely on cortical actin reorganization, as previously thought, but instead on a cell-cycle-dependent bulk actin polymerization wave traveling from the animal to the vegetal pole of the oocyte. This wave functions in segregation by both pulling ooplasm animally and pushing yolk granules vegetally. Using biophysical experimentation and theory, we show that ooplasm pulling is mediated by bulk actin network flows exerting friction forces on the ooplasm, while yolk granule pushing is achieved by a mechanism closely resembling actin comet formation on yolk granules. Our study defines a novel role of cell-cycle-controlled bulk actin polymerization waves in oocyte polarization via ooplasmic segregation.}, author = {Shamipour, Shayan and Kardos, Roland and Xue, Shi-lei and Hof, Björn and Hannezo, Edouard B and Heisenberg, Carl-Philipp J}, issn = {10974172}, journal = {Cell}, number = {6}, pages = {1463--1479.e18}, publisher = {Elsevier}, title = {{Bulk actin dynamics drive phase segregation in zebrafish oocytes}}, doi = {10.1016/j.cell.2019.04.030}, volume = {177}, year = {2019}, }