@article{2a7dab0e9d944617b07bbc343118b277,
title = "Mapping the subcellular mechanical properties of live cells in tissues with fluorescence emission-Brillouin imaging",
abstract = "Extracellular matrices (ECMs) are central to the advent of multicellular life, and their mechanical propertiesare modulated by and impinge on intracellular signaling pathways that regulate vital cellular functions. High spatial-resolution mapping of mechanical properties in live cells is, however, extremely challenging. Thus, our understanding of how signaling pathways process physiological signals to generate appropriate mechanical responses is limited. We introduce fluorescence emission-Brillouin scattering imaging (FBi), a method for the parallel and all-optical measurements of mechanical properties and fluorescence at the submicrometer scale in living organisms. Using FBi, we showed thatchanges in cellular hydrostatic pressure and cytoplasm viscoelasticity modulate the mechanical signatures of plant ECMs. We further established that the measured {"}stiffness{"} of plant ECMs is symmetrically patternedin hypocotyl cells undergoing directional growth. Finally, application of this method to Arabidopsis thaliana with photoreceptor mutants revealed that red and far-red light signals are essential modulators of ECM viscoelasticity. By mapping the viscoelastic signatures of a complex ECM, we provide proof of principlefor the organism-wide applicability of FBi for measuring the mechanical outputs of intracellular signaling pathways. As such, our work has implications for investigations of mechanosignaling pathways and developmental biology.",
keywords = "Extracellular-matrix, Optical microscopy, Refractive-index, Force microscopy, Plant-tissue, Vipa etalons, Cellulose, Growth, Wall, Vivo",
author = "Kareem Elsayad and Stephanie Werner and Mar{\c c}al Gallem{\'i} and Jixiang Kong and Guajardo, \{Edmundo R.S{\'a}nchez\} and Lijuan Zhang and Yvon Jaillais and Thomas Greb and Youssef Belkhadir",
note = "Funding Information: We thank R. Latham and M. Zimmer (Institute of Molecular Pathology, Vienna, Austria) for preparing calibration samples and M. Platre for help in raising the35S::Lti6-td Tomato lines. We are grateful to A. Aszodi and A. Gyenesei [Bioinformatics and Scientific Computing Facility, Vienna Biocenter Core Facility (VBCF)] for expert guidanceon the statistical analysis. We also thank the VBCF Plant Sciences facilities for theuse of the plant growth chambers. We would also like to thank N. Geldner for sharing theCASP1::mCherrySYP122 Arabidopsis transgenic line. We also thank J. M. Watson for providing constructive comments on our article. Finally, we thank N. Daubel for technical advices. Funding: K.E., E.R.S.G., and L.Z. acknowledge funding from the Austrian Federal Ministry of Science, Research \& Economy, and the City of Vienna through the VBCF.This work was supported by grants from the Austrian Academy of Science through the Gregor Mendel Institute (Y.B. and T.G.). This work was also supported by Austrian Science Fund (FWF) grant P25594-168 B21 and a Heisenberg Fellowship from the German Research Foundation (DFG, GR 2104/4-1) to T.G. Author contributions: K.E., T.G, J.K., and Y.B. conceived and designed the experiments. K.E., E.R.S.G., and L.Z. constructed the FBi setup. J.K., M.G., S.W., and K.E. performed the experiments. K.E., M.G., and J.K. analyzed the data. Y.J. provided reagents. K.E. and Y.B. wrote the manuscript with input fromthe other authors. Competing interests: The authors declare that they have no competing interests. Data and materials availability: Custom MATLAB scripts are available upon request or from the Web site: www.vbcf.ac.at/advmicro.",
year = "2016",
month = jul,
day = "5",
doi = "10.1126/scisignal.aaf6326",
language = "English",
volume = "9",
journal = "Science Signaling",
issn = "1945-0877",
publisher = "American Association for the Advancement of Science",
number = "435",
}