scholarly journals The interplay of stiffness and force anisotropies drives embryo elongation

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Thanh Thi Kim Vuong-Brender ◽  
Martine Ben Amar ◽  
Julien Pontabry ◽  
Michel Labouesse

The morphogenesis of tissues, like the deformation of an object, results from the interplay between their material properties and the mechanical forces exerted on them. The importance of mechanical forces in influencing cell behaviour is widely recognized, whereas the importance of tissue material properties, in particular stiffness, has received much less attention. Using Caenorhabditis elegans as a model, we examine how both aspects contribute to embryonic elongation. Measuring the opening shape of the epidermal actin cortex after laser nano-ablation, we assess the spatiotemporal changes of actomyosin-dependent force and stiffness along the antero-posterior and dorso-ventral axis. Experimental data and analytical modelling show that myosin-II-dependent force anisotropy within the lateral epidermis, and stiffness anisotropy within the fiber-reinforced dorso-ventral epidermis are critical in driving embryonic elongation. Together, our results establish a quantitative link between cortical tension, material properties and morphogenesis of an entire embryo.

2016 ◽  
Author(s):  
Thanh TK Vuong-Brender ◽  
Martine Ben Amar ◽  
Julien Pontabry ◽  
Michel Labouesse

AbstractThe morphogenesis of tissues, like the deformation of an object, results from the interplay between their material properties and the mechanical forces exerted on them. Whereas the importance of mechanical forces in influencing cell behaviour is widely recognized, the importance of tissue material properties, in particular stiffness, has received much less attention. Using C. elegans as a model, we examine how both aspects contribute to embryonic elongation. Measuring the opening shape of the epidermal actin cortex after laser nano-ablation, we assess the spatiotemporal changes of actomyosin-dependent force and stiffness along the antero-posterior and dorso-ventral axis. Experimental data and analytical modelling show that myosin II-dependent force anisotropy within the lateral epidermis, and stiffness anisotropy within the fiber-reinforced dorso-ventral epidermis are critical to drive embryonic elongation. Together, our results establish a quantitative link between cortical tension, material properties and morphogenesis of an entire embryo.


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Felix Spira ◽  
Sara Cuylen-Haering ◽  
Shalin Mehta ◽  
Matthias Samwer ◽  
Anne Reversat ◽  
...  

The actomyosin ring generates force to ingress the cytokinetic cleavage furrow in animal cells, yet its filament organization and the mechanism of contractility is not well understood. We quantified actin filament order in human cells using fluorescence polarization microscopy and found that cleavage furrow ingression initiates by contraction of an equatorial actin network with randomly oriented filaments. The network subsequently gradually reoriented actin filaments along the cell equator. This strictly depended on myosin II activity, suggesting local network reorganization by mechanical forces. Cortical laser microsurgery revealed that during cytokinesis progression, mechanical tension increased substantially along the direction of the cell equator, while the network contracted laterally along the pole-to-pole axis without a detectable increase in tension. Our data suggest that an asymmetric increase in cortical tension promotes filament reorientation along the cytokinetic cleavage furrow, which might have implications for diverse other biological processes involving actomyosin rings.


Author(s):  
Kurosh Darvish ◽  
Libor Lobovsky ◽  
Sang-Hyun Lee

A hyperelastic material with linear viscoelasticity was used to characterize the mechanical behavior of aortic tissue based on literature and new experimental data. It was shown that the previous data led to contradictory uniaxial and biaxial responses. A set of new material properties were identified which closely described the experimental data for strains below 40%.


2019 ◽  
Vol 48 (2) ◽  
pp. 245-260.e7 ◽  
Author(s):  
Maria Duda ◽  
Natalie J. Kirkland ◽  
Nargess Khalilgharibi ◽  
Melda Tozluoglu ◽  
Alice C. Yuen ◽  
...  

2015 ◽  
Vol 112 (5) ◽  
pp. 1428-1433 ◽  
Author(s):  
Alexandra Surcel ◽  
Win Pin Ng ◽  
Hoku West-Foyle ◽  
Qingfeng Zhu ◽  
Yixin Ren ◽  
...  

Current approaches to cancer treatment focus on targeting signal transduction pathways. Here, we develop an alternative system for targeting cell mechanics for the discovery of novel therapeutics. We designed a live-cell, high-throughput chemical screen to identify mechanical modulators. We characterized 4-hydroxyacetophenone (4-HAP), which enhances the cortical localization of the mechanoenzyme myosin II, independent of myosin heavy-chain phosphorylation, thus increasing cellular cortical tension. To shift cell mechanics, 4-HAP requires myosin II, including its full power stroke, specifically activating human myosin IIB (MYH10) and human myosin IIC (MYH14), but not human myosin IIA (MYH9). We further demonstrated that invasive pancreatic cancer cells are more deformable than normal pancreatic ductal epithelial cells, a mechanical profile that was partially corrected with 4-HAP, which also decreased the invasion and migration of these cancer cells. Overall, 4-HAP modifies nonmuscle myosin II-based cell mechanics across phylogeny and disease states and provides proof of concept that cell mechanics offer a rich drug target space, allowing for possible corrective modulation of tumor cell behavior.


2014 ◽  
Vol 1648 ◽  
Author(s):  
Michael Culler ◽  
Keri A. Ledford ◽  
Jason H. Nadler

ABSTRACTRemora fish are capable of fast, reversible and reliable adhesion to a wide variety of both natural and artificial marine hosts through a uniquely evolved dorsal pad. This adhesion is partially attributed to suction, which requires a robust seal between the pad interior and the ambient environment. Understanding the behavior of remora adhesion based on measurable surface parameters and material properties is a critical step when creating artificial, bio-inspired devices. In this work, structural and fluid finite element models (FEM) based on a simplified “unit cell” geometry were developed to predict the behavior of the seal with respect to host/remora surface topology and tissue material properties.


2020 ◽  
Vol 375 (1809) ◽  
pp. 20190551 ◽  
Author(s):  
Adam C. Martin

During tissue morphogenesis, mechanical forces are propagated across tissues, resulting in tissue shape changes. These forces in turn can influence cell behaviour, leading to a feedback process that can be described as self-organizing. Here, I discuss cytoskeletal self-organization and point to evidence that suggests its role in directing force during morphogenesis. During Drosophila mesoderm invagination, the shape of the region of cells that initiates constriction creates a mechanical pattern that in turn aligns the cytoskeleton with the axis of greatest resistance to contraction. The wild-type direction of the force controls the shape and orientation of the invaginating mesoderm. Given the ability of the actomyosin cytoskeleton to self-organize, these types of feedback mechanisms are likely to play important roles in a range of different morphogenetic events. This article is part of the discussion meeting issue ‘Contemporary morphogenesis'.


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