SUSTAINED MECHANICAL STRESS ALTERS THE DYNAMICS AND MOLECULAR RESPONSE OF FOCAL ADHESIONS IN MAMMARY EPITHELIAL CELLS

LORENA SIGAUT; JUAN E. BURDISSO; MICAELA BIANCHI; LÍA I. PIETRASANTA; CATALINA VON BILDERLING; LAURA GASTALDI

C.A.B.A.

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Sociedades de Biociencias

Cells are constantly subject to different external mechanical stimuli under normal physiological conditions. Cellular response and adaptation to these mechanical stimuli are crucial in cellular functions and processes1. Many of the biological responses to external forces are originated in specialized structures, focal adhesions, which mechanically connect cells with the extracellular matrix via integrin membrane receptors. Focal adhesions are large, transient multiprotein complexes, their formation, development and disassembly are force-dependent2. Characterizing how these structures dynamically respond in the presence of a mechanical stimulus is essential for understanding different processes, such as cell adhesion, migration, motility and proliferation.In this work, we explored the changes generated in the dynamics of focal adhesions, in HC11 non-tumorigenic mouse mammary epithelial cells, in response to a global external mechanical stimulation that resembles the physiological stimuli to which these cells are subjected. To perform controlled and reproducible mechanical stimulus we use a mechanical stretchingdevice3 that allows sustained equibiaxial stretching of an elastic silicon membrane in which cells are grown, while evaluating the cell-responses by different fluorescence microscopy techniques. We were able to follow focal adhesion dynamics during stretching experiments, by imaging living cells expressing fluorescently tagged proteins, observing an enhanced persistency offocal adhesions as well as an increase in their size. At a molecular level, we explored the effect of external equibiaxial strain on two adhesion proteins postulated as mechanosensors: zyxin and vinculin. We found that increasing normal strain in HC11 living cells, not only induce focal adhesions persistency together with an increase in their size, but also raises of zyxin and vinculin have been widely studied, the influence of a direct mechanical change of the substrate on these proteins at a molecular level has not been established before.References: 1- Horton E.R. et al. J Cell Sci. 2016, 129 (22): 4159; Marti A. et al. Eur J Cell Biol 1997, 73(2):158; 2- Wolfenson H. et al. Cell Motil. cytoskeleton 2009, 66: 1017. Horton et al. J Cell Sci. 2016,129 (22): 4159. 3- Adapted from: Quaglino A. et al. BMC Cell Biol. 2009, 10: 55 and Lee A.A., et al. Am. J. Physiol. 1996, 271: C1400.Acknowledgments: UBA, CONICET, ANPCyT.