title: Intracellular dynamics measurements with full field optical coherence tomography suggest hindering effect of actomyosin contractility on organelle transport.
abstract: Intracellular motion can be quantitatively monitored in tissues using coherence-gated microscopic techniques. With full-field optical coherence tomography (FFOCT), the use of high numerical aperture microscope objectives provides a high resolution mapping of intracellular dynamics that are probed with subwavelength sensitivity. In the upper temporal bandwidth that we have used (1-6 Hz) the main contribution to the dynamic signal arises from the overall dynamical, optically heterogeneous cytoplasm. We propose a method to specifically study the impact of actomyosin contractility on the intracellular dynamic signal by performing high throughput, comparative measurements of multicellular aggregates with and without blebbistatin action, a selective inhibitor of class-II myosins that disrupts actomyosin contractile activity. Our results indicate a significant increase in the fraction of the signal that decorrelates within 1 second after inhibition of contractility. This observation mitigates the anticipated importance of actomyosin contractile forces to directly move organelles, but highlights their role in hindering organelle transport via their stiffening effect of the viscoelastic cytoplasm.
authors.affiliation: Institut Langevin, INSERM, ESPCI Paris, PSL Research University, 1 rue Jussieu, Paris, France.
authors.forename: Charles-Edouard
authors.initials: CE
authors.lastname: Leroux
authors.affiliation: Institut Curie, PSL Research University, CNRS, UMR 144, F-75005, Paris, France.
authors.forename: Fabien
authors.initials: F
authors.lastname: Bertillot
authors.affiliation: Institut Langevin, INSERM, ESPCI Paris, PSL Research University, 1 rue Jussieu, Paris, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Thouvenin
authors.affiliation: Institut Langevin, INSERM, ESPCI Paris, PSL Research University, 1 rue Jussieu, Paris, France.
authors.forename: Albert-Claude
authors.initials: AC
authors.lastname: Boccara
keywords: (110.4500) Optical coherence tomography; (170.1530) Cell analysis; (170.3880) Medical and biological imaging; (170.6480) Spectroscopy, speckle; (170.6510) Spectroscopy, tissue diagnostics