Surabhi Sonam - Academia.edu (original) (raw)
Papers by Surabhi Sonam
Nature Materials, 2021
A Correction to this paper has been published: https://doi.org/10.1038/s41563-021-00974-9.
Nature Materials
Actomyosin machinery endows cells with contractility at a single cell level. However, within a mo... more Actomyosin machinery endows cells with contractility at a single cell level. However, within a monolayer, cells can be contractile or extensile based on the direction of pushing or pulling forces exerted by their neighbours or on the substrate. It has been shown that a monolayer of fibroblasts behaves as a contractile system while epithelial or neural progentior monolayers behave as an extensile system. Through a combination of cell culture experiments and in silico modeling, we reveal the mechanism behind this switch in extensile to contractile as the weakening of intercellular contacts. This switch promotes the buildup of tension at the cell-substrate interface through an increase in actin stress fibers and traction forces. This is accompanied by mechanotransductive changes in vinculin and YAP activation. We further show that contractile and extensile differences in cell activity sort cells in mixtures, uncovering a generic mechanism for pattern formation during cell competition, and morphogenesis. Main text The ability of cell monolayers to self-organize, migrate and evolve depends crucially on the interplay between cell-matrix and cell-cell interactions [1-4] which controls various phenomena including tissue morphogenesis [5, 6], epithelial-mesenchymal transition [1], wound healing and tumor progression [7]. Cells are active systems, engines that operate away from thermal equilibrium, transducing chemical energy into motion. Single isolated cells generate contractile force dipoles: the resultant of the forces due to actomyosin contraction, pulling on focal adhesion sites on the substrate, is typically a pair of approximately equal and opposite forces acting inwards along the cellular long axis [8] (Figure 1a). It is reasonable to expect that contractile particles also generate contractile behaviour in the monolayer [9]. However, at the collective cell level, epithelial monolayers [10, 11] and a monolayer of neural progentior cells display
ABSTRACTQuantification of skeletal muscle functional contraction is essential to assess the outco... more ABSTRACTQuantification of skeletal muscle functional contraction is essential to assess the outcomes of therapeutic procedures for muscular disorders. Muscle three-dimensional “Organ-on-chip” models usually require a substantial amount of biological material, which is problematic in the context of limited patient sample. Here we developed a miniaturized 3D myotube culture chip with contraction monitoring capacity. Optimized micropatterned substrate design enabled to obtain high culture yields in tightly controlled microenvironments. Spontaneous contractions in myotubes derived from primary human myoblasts were observed. Analysis of nuclear morphology confirmed a similar organization between obtained myotubes and in vivo myofibers. LMNA-related Congenital Muscular Dystrophy (L-CMD) was modelled with successful development of mutant 3D myotubes displaying contractile dysfunction. This technology can thus be used to study contraction characteristics and evaluate how diseases affect mus...
Actomyosin machinery endows cells with contractility at a single cell level. However, at a tissue... more Actomyosin machinery endows cells with contractility at a single cell level. However, at a tissue scale, cells can show either contractile or extensile behaviour based on the direction of pushing or pulling forces due to neighbour interactions or substrate interactions. Previous studies have shown that a monolayer of fibroblasts behaves as a contractile system1 while a monolayer of epithelial cells2,3 or neural crest cells behaves as an extensile system.4 How these two contradictory sources of force generation can coexist has remained unexplained. Through a combination of experiments using MDCK (Madin Darby Canine Kidney) cells, and in-silico modeling, we uncover the mechanism behind this switch in behaviour of epithelial cell monolayers from extensile to contractile as the weakening of intercellular contacts. We find that this switch in active behaviour also promotes the buildup of tension at the cell-substrate interface through an increase in actin stress fibers and higher tractio...
Nature communications, Nov 15, 2017
Collective epithelial behaviors are essential for the development of lumens in organs. However, c... more Collective epithelial behaviors are essential for the development of lumens in organs. However, conventional assays of planar systems fail to replicate cell cohorts of tubular structures that advance in concerted ways on out-of-plane curved and confined surfaces, such as ductal elongation in vivo. Here, we mimic such coordinated tissue migration by forming lumens of epithelial cell sheets inside microtubes of 1-10 cell lengths in diameter. We show that these cell tubes reproduce the physiological apical-basal polarity, and have actin alignment, cell orientation, tissue organization, and migration modes that depend on the extent of tubular confinement and/or curvature. In contrast to flat constraint, the cell sheets in a highly constricted smaller microtube demonstrate slow motion with periodic relaxation, but fast overall movement in large microtubes. Altogether, our findings provide insights into the emerging migratory modes for epithelial migration and growth under tubular confine...
Proceedings of the National Academy of Sciences
Microfluidics has been the key component for many applications, including biomedical devices, che... more Microfluidics has been the key component for many applications, including biomedical devices, chemical processors, microactuators, and even wearable devices. This technology relies on soft lithography fabrication which requires cleanroom facilities. Although popular, this method is expensive and labor-intensive. Furthermore, current conventional microfluidic chips precludes reconfiguration, making reiterations in design very time-consuming and costly. To address these intrinsic drawbacks of microfabrication, we present an alternative solution for the rapid prototyping of microfluidic elements such as microtubes, valves, and pumps. In addition, we demonstrate how microtubes with channels of various lengths and cross-sections can be attached modularly into 2D and 3D microfluidic systems for functional applications. We introduce a facile method of fabricating elastomeric microtubes as the basic building blocks for microfluidic devices. These microtubes are transparent, biocompatible, h...
Biology of the Cell
Actin cytoskeleton contractility plays a critical role in morphogenetic processes by generating f... more Actin cytoskeleton contractility plays a critical role in morphogenetic processes by generating forces that are then transmitted to cell-cell and cell-ECM adhesion complexes. In turn, mechanical properties of the environment are sensed and transmitted to the cytoskeleton at cell adhesion sites, influencing cellular processes such as cell migration, differentiation and survival. Anchoring of the actomyosin cytoskeleton to adhesion sites is mediated by adaptor proteins such as talin or α-catenin that link F-actin to transmembrane cell adhesion receptors, thereby allowing mechanical coupling between the intracellular and extracellular compartments. Thus, a key issue is to be able to measure the forces generated by actomyosin and transmitted to the adhesion complexes. Approaches developed in cells and those probing single molecule mechanical properties of α-catenin molecules allowed to identify α-catenin, an F-actin binding protein which binds to the cadherin complexes as a major player in cadherin-based mechanotransduction. However, it is still very difficult to bridge intercellular forces measured at cellular levels and those measured at the single-molecule level. Here, we applied an intermediate approach allowing reconstruction of the actomyosin-α-catenin complex in acellular conditions to probe directly the transmitted forces. For this, we combined micropatterning of purified α-catenin and spontaneous actomyosin network assembly in the presence of G-actin and Myosin II with microforce sensor arrays used so far to measure cell-generated forces. Using this method, we show that self-organizing actomyosin bundles bound to micrometric α-catenin patches can apply near-nanoNewton forces, paving the way for future studies on molecular/cellular mechanotarnsduction and mechanosensing. This article is protected by copyright. All rights reserved.
Methods in cell biology, 2018
Epithelial cells demonstrate different collective migratory modes when encountering two (2D) and ... more Epithelial cells demonstrate different collective migratory modes when encountering two (2D) and three dimensional (3D) microenvironment. While planar micropatterns and constraint have been shown to strongly impact collective cell migration (CCM), how out-of-plane curvature and 3D confinement will affect epithelial organization and dynamics remains largely unknown. This is likely due to lack of proper 3D microscaffolds for studying CCM. In this chapter, we briefly review the latest achievement in microengineering approaches to control 3D microenvironment of epithelial development. Then, we introduce convenient and simple methods of fabricating elastomeric tubular biocompatible microchannels as 3D cell culture scaffolds. Afterwards, we describe in detail the experimental set-up for observing 3D coordinated cell migration on curved surfaces and under spatial constraint. Finally, we provide an approach to analyze 3D dynamics using available techniques for 2D images.
Nature Materials, 2021
A Correction to this paper has been published: https://doi.org/10.1038/s41563-021-00974-9.
Nature Materials
Actomyosin machinery endows cells with contractility at a single cell level. However, within a mo... more Actomyosin machinery endows cells with contractility at a single cell level. However, within a monolayer, cells can be contractile or extensile based on the direction of pushing or pulling forces exerted by their neighbours or on the substrate. It has been shown that a monolayer of fibroblasts behaves as a contractile system while epithelial or neural progentior monolayers behave as an extensile system. Through a combination of cell culture experiments and in silico modeling, we reveal the mechanism behind this switch in extensile to contractile as the weakening of intercellular contacts. This switch promotes the buildup of tension at the cell-substrate interface through an increase in actin stress fibers and traction forces. This is accompanied by mechanotransductive changes in vinculin and YAP activation. We further show that contractile and extensile differences in cell activity sort cells in mixtures, uncovering a generic mechanism for pattern formation during cell competition, and morphogenesis. Main text The ability of cell monolayers to self-organize, migrate and evolve depends crucially on the interplay between cell-matrix and cell-cell interactions [1-4] which controls various phenomena including tissue morphogenesis [5, 6], epithelial-mesenchymal transition [1], wound healing and tumor progression [7]. Cells are active systems, engines that operate away from thermal equilibrium, transducing chemical energy into motion. Single isolated cells generate contractile force dipoles: the resultant of the forces due to actomyosin contraction, pulling on focal adhesion sites on the substrate, is typically a pair of approximately equal and opposite forces acting inwards along the cellular long axis [8] (Figure 1a). It is reasonable to expect that contractile particles also generate contractile behaviour in the monolayer [9]. However, at the collective cell level, epithelial monolayers [10, 11] and a monolayer of neural progentior cells display
ABSTRACTQuantification of skeletal muscle functional contraction is essential to assess the outco... more ABSTRACTQuantification of skeletal muscle functional contraction is essential to assess the outcomes of therapeutic procedures for muscular disorders. Muscle three-dimensional “Organ-on-chip” models usually require a substantial amount of biological material, which is problematic in the context of limited patient sample. Here we developed a miniaturized 3D myotube culture chip with contraction monitoring capacity. Optimized micropatterned substrate design enabled to obtain high culture yields in tightly controlled microenvironments. Spontaneous contractions in myotubes derived from primary human myoblasts were observed. Analysis of nuclear morphology confirmed a similar organization between obtained myotubes and in vivo myofibers. LMNA-related Congenital Muscular Dystrophy (L-CMD) was modelled with successful development of mutant 3D myotubes displaying contractile dysfunction. This technology can thus be used to study contraction characteristics and evaluate how diseases affect mus...
Actomyosin machinery endows cells with contractility at a single cell level. However, at a tissue... more Actomyosin machinery endows cells with contractility at a single cell level. However, at a tissue scale, cells can show either contractile or extensile behaviour based on the direction of pushing or pulling forces due to neighbour interactions or substrate interactions. Previous studies have shown that a monolayer of fibroblasts behaves as a contractile system1 while a monolayer of epithelial cells2,3 or neural crest cells behaves as an extensile system.4 How these two contradictory sources of force generation can coexist has remained unexplained. Through a combination of experiments using MDCK (Madin Darby Canine Kidney) cells, and in-silico modeling, we uncover the mechanism behind this switch in behaviour of epithelial cell monolayers from extensile to contractile as the weakening of intercellular contacts. We find that this switch in active behaviour also promotes the buildup of tension at the cell-substrate interface through an increase in actin stress fibers and higher tractio...
Nature communications, Nov 15, 2017
Collective epithelial behaviors are essential for the development of lumens in organs. However, c... more Collective epithelial behaviors are essential for the development of lumens in organs. However, conventional assays of planar systems fail to replicate cell cohorts of tubular structures that advance in concerted ways on out-of-plane curved and confined surfaces, such as ductal elongation in vivo. Here, we mimic such coordinated tissue migration by forming lumens of epithelial cell sheets inside microtubes of 1-10 cell lengths in diameter. We show that these cell tubes reproduce the physiological apical-basal polarity, and have actin alignment, cell orientation, tissue organization, and migration modes that depend on the extent of tubular confinement and/or curvature. In contrast to flat constraint, the cell sheets in a highly constricted smaller microtube demonstrate slow motion with periodic relaxation, but fast overall movement in large microtubes. Altogether, our findings provide insights into the emerging migratory modes for epithelial migration and growth under tubular confine...
Proceedings of the National Academy of Sciences
Microfluidics has been the key component for many applications, including biomedical devices, che... more Microfluidics has been the key component for many applications, including biomedical devices, chemical processors, microactuators, and even wearable devices. This technology relies on soft lithography fabrication which requires cleanroom facilities. Although popular, this method is expensive and labor-intensive. Furthermore, current conventional microfluidic chips precludes reconfiguration, making reiterations in design very time-consuming and costly. To address these intrinsic drawbacks of microfabrication, we present an alternative solution for the rapid prototyping of microfluidic elements such as microtubes, valves, and pumps. In addition, we demonstrate how microtubes with channels of various lengths and cross-sections can be attached modularly into 2D and 3D microfluidic systems for functional applications. We introduce a facile method of fabricating elastomeric microtubes as the basic building blocks for microfluidic devices. These microtubes are transparent, biocompatible, h...
Biology of the Cell
Actin cytoskeleton contractility plays a critical role in morphogenetic processes by generating f... more Actin cytoskeleton contractility plays a critical role in morphogenetic processes by generating forces that are then transmitted to cell-cell and cell-ECM adhesion complexes. In turn, mechanical properties of the environment are sensed and transmitted to the cytoskeleton at cell adhesion sites, influencing cellular processes such as cell migration, differentiation and survival. Anchoring of the actomyosin cytoskeleton to adhesion sites is mediated by adaptor proteins such as talin or α-catenin that link F-actin to transmembrane cell adhesion receptors, thereby allowing mechanical coupling between the intracellular and extracellular compartments. Thus, a key issue is to be able to measure the forces generated by actomyosin and transmitted to the adhesion complexes. Approaches developed in cells and those probing single molecule mechanical properties of α-catenin molecules allowed to identify α-catenin, an F-actin binding protein which binds to the cadherin complexes as a major player in cadherin-based mechanotransduction. However, it is still very difficult to bridge intercellular forces measured at cellular levels and those measured at the single-molecule level. Here, we applied an intermediate approach allowing reconstruction of the actomyosin-α-catenin complex in acellular conditions to probe directly the transmitted forces. For this, we combined micropatterning of purified α-catenin and spontaneous actomyosin network assembly in the presence of G-actin and Myosin II with microforce sensor arrays used so far to measure cell-generated forces. Using this method, we show that self-organizing actomyosin bundles bound to micrometric α-catenin patches can apply near-nanoNewton forces, paving the way for future studies on molecular/cellular mechanotarnsduction and mechanosensing. This article is protected by copyright. All rights reserved.
Methods in cell biology, 2018
Epithelial cells demonstrate different collective migratory modes when encountering two (2D) and ... more Epithelial cells demonstrate different collective migratory modes when encountering two (2D) and three dimensional (3D) microenvironment. While planar micropatterns and constraint have been shown to strongly impact collective cell migration (CCM), how out-of-plane curvature and 3D confinement will affect epithelial organization and dynamics remains largely unknown. This is likely due to lack of proper 3D microscaffolds for studying CCM. In this chapter, we briefly review the latest achievement in microengineering approaches to control 3D microenvironment of epithelial development. Then, we introduce convenient and simple methods of fabricating elastomeric tubular biocompatible microchannels as 3D cell culture scaffolds. Afterwards, we describe in detail the experimental set-up for observing 3D coordinated cell migration on curved surfaces and under spatial constraint. Finally, we provide an approach to analyze 3D dynamics using available techniques for 2D images.