Browsing by Author "Ravasio, Andrea"
Now showing 1 - 12 of 12
Results Per Page
Sort Options
- ItemA computational framework for testing hypotheses of the minimal mechanical requirements for cell aggregation using early annual killifish embryogenesis as a model(FRONTIERS MEDIA SA, 2023) Montenegro-Rojas, Ignacio; Yanez, Guillermo; Skog, Emily; Guerrero-Calvo, Oscar; Andaur-Lobos, Martin; Dolfi, Luca; Cellerino, Alessandro; Cerda, Mauricio; Concha, Miguel L.; Bertocchi, Cristina; Rojas, Nicolas O.; Ravasio, Andrea; Rudge, Timothy J.Introduction: Deciphering the biological and physical requirements for the outset of multicellularity is limited to few experimental models. The early embryonic development of annual killifish represents an almost unique opportunity to investigate de novo cellular aggregation in a vertebrate model. As an adaptation to seasonal drought, annual killifish employs a unique developmental pattern in which embryogenesis occurs only after undifferentiated embryonic cells have completed epiboly and dispersed in low density on the egg surface. Therefore, the first stage of embryogenesis requires the congregation of embryonic cells at one pole of the egg to form a single aggregate that later gives rise to the embryo proper. This unique process presents an opportunity to dissect the self-organizing principles involved in early organization of embryonic stem cells. Indeed, the physical and biological processes required to form the aggregate of embryonic cells are currently unknown., Methods: Here, we developed an in silico, agent-based biophysical model that allows testing how cell-specific and environmental properties could determine the aggregation dynamics of early Killifish embryogenesis. In a forward engineering approach, we then proceeded to test two hypotheses for cell aggregation (cell-autonomous and a simple taxis model) as a proof of concept of modeling feasibility. In a first approach (cell autonomous system), we considered how intrinsic biophysical properties of the cells such as motility, polarity, density, and the interplay between cell adhesion and contact inhibition of locomotion drive cell aggregation into self-organized clusters. Second, we included guidance of cell migration through a simple taxis mechanism to resemble the activity of an organizing center found in several developmental models., Results: Our numerical simulations showed that random migration combined with low cell-cell adhesion is sufficient to maintain cells in dispersion and that aggregation can indeed arise spontaneously under a limited set of conditions, but, without environmental guidance, the dynamics and resulting structures do not recapitulate in vivo observations., Discussion: Thus, an environmental guidance cue seems to be required for correct execution of early aggregation in early killifish development. However, the nature of this cue (e.g., chemical or mechanical) can only be determined experimentally. Our model provides a predictive tool that could be used to better characterize the process and, importantly, to design informed experimental strategies.
- ItemA processing product of thePlasmodium falciparumreticulocyte binding proteinRH1shows a close association withAMA1during junction formation(2020) Gunalan, K.; Gao, X. H.; Yap, S. S. L.; Lai, S. K.; Ravasio, Andrea; Ganesan, S.; Li, H. Y.; Preiser, P. R.
- ItemAuthor Correction: Single-cell analysis of EphA clustering phenotypes to probe cancer cell heterogeneity(2020) Ravasio, Andrea; Myaing, Myint Z.; Chia, Shumei; Arora, Aditya; Sathe, Aneesh; Cao, Elaine Yiqun; Bertocchi, Cristina; Sharma, Ankur; Arasi, Bakya; Chung, Vin Yee; Greene, Adrienne C.; Tan, Tuan Zea; Chen, Zhongwen; Ong, Hui Ting; Iyer, N. Gopalakrishna; Huang, Ruby YunJu; DasGupta, Ramanuj; Groves, Jay T.; Viasnoff, Virgile
- ItemCohesive energy and interaction of superparamagnetic aggregates(2020) Rojas, N.; Cerda, M.; Ravasio, Andrea; Rudge, Timothy
- ItemLarge-scale curvature sensing by directional actin flow drives cellular migration mode switching(2019) Chen, T.; Callan-Jones, A.; Fedorov, E.; Ravasio, Andrea; Brugues, A. Ong, H.T.; Toyama, Y.; Low, B.C.; Trepat, X.; Shemesh, T.; Voituriez, R.; Ladoux, B.
- ItemMechanical Roles of Vinculin/β-catenin interaction in Adherens Junction(2019) Bertocchi , Cristina; Ravasio, Andrea; Ong, Hui Ting; Toyama, Yusuke; Kanchanawong, PakornMechanical force transmission through the adherens junctions (AJs) are highly regulated processes essential for multicellular organization of tissues. AJ proteins such as E-cadherin, α-catenin, and vinculin have been shown to be sensing or bearing mechanical forces being transmitted between the actin cytoskeleton and the intercellular contacts. However, the molecular organization and connectivity of these components remains not well understood. Using a super-resolution microscopy approach, we report that vinculin, once activated, could form a direct structural connection with β-catenin, which can bypass α-catenin, one of the main mechanotransducers in AJs. Direct vinculin/β-catenin interaction is capable of supporting mechanical tension and contributes to the stabilization of the cadherin-catenin complexes. These findings suggest a multi-step model for the force-dependent reinforcement of AJs whereby α-catenin may serve as the initial catalytic activator of vinculin, followed by vinculin translocation to form a direct link between E-cadherin-bound β-catenin and the actin cytoskeleton
- ItemMechanoautophagy: Synergies Between Autophagy and Cell Mechanotransduction at Adhesive Complexes(FRONTIERS MEDIA SA, 2022) Ravasio, Andrea; Morselli, Eugenia; Bertocchi, CristinaCells are exposed and respond to various mechanical forces and physical cues stemming from their environment. This interaction has been seen to differentially regulate various cellular processes for maintenance of homeostasis, of which autophagy represents one of the major players. In addition, autophagy has been suggested to regulate mechanical functions of the cells including their interaction with the environment. In this minireview, we summarize the state of the art of the fascinating interplay between autophagy and the mechanotransduction machinery associated with cell adhesions, that we name center dot Mechanoautophagy center dot
- ItemMicrofabrication approaches for oral research and clinical dentistry(2023) Tiozzo-Lyon, Paola; Andrade, Matías; Leiva-Sabadini, Camila; Morales, José; Olivares, Antonia; Ravasio, Andrea; Aguayo Paul, Sebastian DanielCurrently, there is a variety of laboratory tools and strategies that have been developed to investigate in-vivo processes using in-vitro models. Amongst these, microfabrication represents a disruptive technology that is currently enabling next-generation biomedical research through the development of complex laboratory approaches (e.g., microfluidics), engineering of micrometer scale sensors and actuators (micropillars for traction force microscopy), and the creation of environments mimicking cell, tissue, and organ-specific contexts. Although microfabrication has been around for some time, its application in dental and oral research is still incipient. Nevertheless, in recent years multiple lines of research have emerged that use microfabrication-based approaches for the study of oral diseases and conditions with micro- and nano-scale sensitivities. Furthermore, many investigations are aiming to develop clinically relevant microfabrication-based applications for diagnostics, screening, and oral biomaterial manufacturing. Therefore, the objective of this review is to summarize the current application of microfabrication techniques in oral sciences, both in research and clinics, and to discuss possible future applications of these technologies for in-vitro studies and practical patient care. Initially, this review provides an overview of the most employed microfabrication methods utilized in biomedicine and dentistry. Subsequently, the use of micro- and nano-fabrication approaches in relevant fields of dental research such as endodontic and periodontal regeneration, biomaterials research, dental implantology, oral pathology, and biofilms was discussed. Finally, the current and future uses of microfabrication technology for clinical dentistry and how these approaches may soon be widely available in clinics for the diagnosis, prevention, and treatment of relevant pathologies are presented.
- ItemMolecular Insights on Shigellosis: How the Interaction Between Invasin IpaA and Vinculin Hijacks Cellular Mechanotransduction(2023) Bertocchi , Cristina; Morales, Nicole; Ravasio, AndreaWith 270 million infections annually and nearly half a million death a year, shigellosis is a severe intestinal infection caused by bacteria of the Shigella family. Appearance and spread of drug-resistant strains renewed global concerns for public health and finding novel targets for treatment is fast becoming a priority. To this end, invasins are a potentially good candidate. Also called Ipa(s), which is the short for Invasion Plasmid Antigen, invasins play a key role in mediating bacterial invasion and infection of the host cell. Importantly, they have been reported to hijack inbuilt mechanical capability of the host cells such as cell adhesion and active processes mediated by the actin cytoskeleton to enable bacterial ingress into the host cells. IpaA is an invasin of particular interest as it presents three motifs that mimic vinculin binding sites and thus it allows IpaA to interact with vinculin, which is one of the most critical regulators of cellular and tissue mechanics. Using a mechanobiology point-of-view, we aim to provide an overview of Shigella´s infection mechanism, to highlight recently discovered molecular mechanisms of IpaA/vinculin interaction and to finally discuss their consequences for epithelial cell and tissue mechanical homeostasis that may result in the symptomatic outcomes seen in severe shigellosis.
- ItemNanoscale architecture of cadherin-based cell adhesions.(2017) Bertocchi, C.; Wang, Y.; Ravasio, Andrea; Hara, Y.; Wu, Y.; Sailov, T.; Baird, M.; Davidson, M. W.; Zaidel Bar, R.; Toyama, Y.; Ladoux, B.; Mege, R. M.; Kanchanawong, P.
- ItemSingle-cell analysis of EphA clustering phenotypes to probe cancer cell heterogeneity(2020) Ravasio, Andrea; Myaing, M. Z.; Chia, S. M.; Arora, A.; Sathe, A.; Cao, E. Y.; Bertocchi, Cristina; Sharma, A.; Arasi, B.; Chung, V. Y.; Green, A. C.; Tan, T. Z.; Chen, Z. W.; Ong, H. T.; Iyer, N. G.; Huang, R. Y.; DasGupta, R.; Groves, J. T.; Viasnoff, V.
- ItemVolumePeeler: a novel FIJI plugin for geometric tissue peeling to improve visualization and quantification of 3D image stacks(BMC, 2023) Gatica, Marilyn; Navarro, Carlos F. F.; Lavado, Alejandro; Reig, German; Pulgar, Eduardo; Llanos, Paula; Haertel, Steffen; Ravasio, Andrea; Bertocchi, Cristina; Concha, Miguel L. L.; Cerda, MauricioMotivation Quantitative descriptions of multi-cellular structures from optical microscopy imaging are prime to understand the variety of three-dimensional (3D) shapes in living organisms. Experimental models of vertebrates, invertebrates and plants, such as zebrafish, killifish, Drosophila or Marchantia, mainly comprise multilayer tissues, and even if microscopes can reach the needed depth, their geometry hinders the selection and subsequent analysis of the optical volumes of interest. Computational tools to "peel" tissues by removing specific layers and reducing 3D volume into planar images, can critically improve visualization and analysis.Results We developed VolumePeeler, a versatile FIJI plugin for virtual 3D "peeling" of image stacks. The plugin implements spherical and spline surface projections. We applied VolumePeeler to perform peeling in 3D images of spherical embryos, as well as non-spherical tissue layers. The produced images improve the 3D volume visualization and enable analysis and quantification of geometrically challenging microscopy datasets.