Photoactivatable compliant substrates for precise analysis of mechanobiological regulation in collective cell migration

Abstract

Event Abstract Back to Event Photoactivatable compliant substrates for precise analysis of mechanobiological regulation in collective cell migration Masao Kamimura1, Kazuo Yamaguchi2 and Jun Nakanishi1 1 National Institute for Materials Science (NIMS), International center for Materials Nanoarchitectonics (MANA), Japan 2 Kanagawa University, Department of Chemistry, School of Science, Japan Introduction: Collective cell migration is the migration of cells in a group. Basically, epithelial cells migrate collectively, whereas mesenchymal cells prefer to migrate as individuals. However, in some spatiotemporally limited situations of life, cells aggressively ignore this rule via epithelial-mesenchymal transition (EMT) and vice versa (MET). This migration plasticity plays a critical role not only in developmental processes, but also in cancer invasion and metastasis. Therefore, understanding their regulation mechanisms is important from both fundamental and applied biology viewpoints. Various soluble factors and gene expression changes has been shown to affect the migration phenotypes, but the contribution of extracellular matrix (ECM) is still unclear. To precisely dissect mechanobiology in collective cell migration, we herein developed photoactivatable compliant substrates with defined material stiffness (Fig. 1) and conducted proof-of-concept experiments with MDCK cells. Materials and Methods: Polyacrylamide (PAAm) gel was used as a baselayer, whose mechanical property can be tuned depending on the mixing ratio of acrylamide and bisacrylamide. The surface of PAAm gel was functionalized with poly(D-lysine) (PDL) via sulfo-SANPAH. Finally, the PDL surface was successively functionalized with two kinds of PEGs (Mw = 5K and 2K) through a photoclevable 2-nitrobenzyl group. The surface is initially non-cell adhesive due to the PEG brushes, but becomes cell-adhesive upon photocleavage of PEG. Cell migration was studied by photo-confining cells in a given geometry and thereafter inducing migration by irradiating surrounding regions (Fig. 2). The migration behavior was recorded in an incubation chamber equipped on a phase-contrast microscope. Results and Discussions: Two differently-stiff PAAm gels were prepared (5 and 55 kPa), whose mechanical property was characterized by the gel indentation assay. The gel surface functionalization with PDL and photocleavable PEG was confirmed from surface zeta potential changes. The photoswitchabile feature was characterized from protein adsorption tests. These results demonstrated that the two gels had different mechanical properties with identical surface chemistry. Then, collective migration behaviors from rectangular and circular clusters were examined. One-directional migration from the rectangular clusters exhibited faster migration rate on the stiffer gel (data not shown). Moreover, the cluster expansion from the circular clusters exhibited qualitatively different behaviors; cells showed collective wavy motions on the stiffer gel, whereas on the softer gel, the cluster started migration after a certain priming time (~6 h) only to single direction (Fig. 3). It should be noted that migration behaviors were almost identical when cells were sparsely seeded as isolated single cells. Therefore, the observed difference in collective migration behaviors is owing to the emerged mechanical sensitivity when the cells become a group. Conclusions: Out photoactivatable compliant substrates revealed qualitative and quantitative difference in collective migration behaviors in MDCK cells depending on the substrate stiffness and initial cell cluster geometries. Further systematic analysis will help us understand the principle in mechanobiological regulation in collective migration. Keywords: mechanical property, stimuli-response, Pattering, matrix-cell interaction Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: New Frontier Oral Topic: Cellular migration and biomaterials Citation: Kamimura M, Yamaguchi K and Nakanishi J (2016). Photoactivatable compliant substrates for precise analysis of mechanobiological regulation in collective cell migration. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.00347 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Masao Kamimura Kazuo Yamaguchi Jun Nakanishi Google Masao Kamimura Kazuo Yamaguchi Jun Nakanishi Google Scholar Masao Kamimura Kazuo Yamaguchi Jun Nakanishi PubMed Masao Kamimura Kazuo Yamaguchi Jun Nakanishi Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. 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