Biomechanics of morphogenesis

Our group is interested in describing the mechanisms at the origin of force generation, coordination and regulation in biological tissues. During Drosophila embryogenesis, dramatic tissue rearrangements occur to shape the organism and form its organs. The embryo undergoes a sequence of morphogenetic movements precisely controlled by complex signalling networks. The origin of the forces driving these morphogenetic movements and how signalling networks coordinates them remains unclear.

We are developing methods to apply controlled forces and measure cellular forces in a developing living organism. We combine these methods with state-of-the-art 3D high-resolution live imaging, Drosophila genetic and quantitative modelling to understand the mechanisms regulating the contraction, the spreading and fusion of biological tissues.

• We are developing new methodologies to induce and measure cellular forces in vivo.
• Combining high-resolution imaging with physical modelling, we are aiming to understand the mechanisms driving contraction of tissues during Drosophila dorsal closure. We found that cells can generate contractile forces by decreasing their volume after apoptosis activation (see Saias et al., 2015) and that cell-cell junctional length is actively controlled by the actomyosin cytoskeleton and recycling machinery to maintain tissue integrity (see Sumi et al. 2018)
• We are designing methods to extract 3D epithelium architecture for the understanding of epithelial fold formation.
• We are investigating the mechanisms controlling epithelial sealing and ensuring a scar-less resulting epithelium.
• In collaboration with J. Jaeger, we investigated the origin of evolutionary-driven changes in morphogenesis between different fly species. We found an evolutionary simplification of the process of epithelial sealing consequent to differences in the arrangement and shape of cell layers without changing the signalling regulatory pathways (See Fraire-Zamora et al., 2018).
• In collaboration with the group of Jordi Casanova, we are investigating the mechanisms underlying renewal of the trachea and ensuring the removal of the larval tracheal cells during Drosophila metamorphosis.
• We are developing tools and models to understand the principles underlying nuclear architecture in interphase and mitosis during neural cell development and embryonic stem cell differentiation. (In collaboration with P. Cosma, M. Mendoza and M. Lakadamyali, ICFO)

Fraire-Zamora JJ, Jaeger J, Solon J.
“Two consecutive microtubule-based epithelial seaming events mediate dorsal closure in the scuttle fly Megaselia abdita”
eLife, 7, 2018.

Sumi A, Hayes P, D’Angelo A, Colombelli J, Salbreux G, Dierkes K, Solon J.
“Adherens junction length during tissue contraction is controlled by the mechanosensitive activity of actomyosin and ju8nctional recycling.”
Dev Cell, 47(4):453-463.e3, 2018.