Epithelial response to stretch during Drosophila dorsal closure: Emergence and control of deformation and polarization patterns

• Autores: Elise Jeanne Marie-Catherine Trubuil
• Directores de la Tesis: Jérôme Solon (dir. tes.), Ugo Mayor Martínez (codir. tes.)
• Lectura: En la Universidad del País Vasco - Euskal Herriko Unibertsitatea ( España ) en 2025
• Idioma: inglés
• Programa de doctorado: Programa de Doctorado en Biología Molecular y Biomedicina / Molecular Biology and Biomedicine por la Universidad del País Vasco/Euskal Herriko Unibertsitatea
• Calificación: Sobresaliente Cum Laude
• Materias:
  • Ciencias médicas
• Enlaces
  • Tesis en acceso abierto en: ADDI
• Resumen

  • The capacity of epithelia to respond properly to stretching is critical in various biological processes, including embryo development, organism homeostasis, and wound healing. A comprehensive understanding of how epithelial tissues respond to stretch is essential for advancing our knowledge on animal morphogenesis and on disorders in tissue homeostasis leading to inflammation or cancer. It has been established that several cellular processes, including proliferation, rearrangements, and changes in cell shape, are essential for the proper response of epithelia to stretch. The objective of this thesis is to deepen our understanding of the mechanisms by which epithelia respond to stretch in vivo, during embryonic development, with a particular focus on the role of cell shape changes and cytoskeletal remodeling. To investigate this, we use as a model the epidermal stretching, which occurs without cell rearrangements or proliferation, and takes place during dorsal closure, an embryogenesis process in Drosophila. Utilizing live microscopy and a thorough quantification protocol, we have identified a pattern of cell shape in the epidermis during closure. Upon stretching, the dorsal epidermal cells exhibit a greater aspect ratio and apical area compared to the ventral cells. Our research also revealed that Cadherin and Myosin II polarize in distinct ways in epidermal cells. Cadherin polarization increases linearly during dorsal closure and correlates with cell elongation. In contrast, Myosin II polarization exhibits a two-step increase, coinciding with an increase in tissue stress. Finally, we have demonstrated that the pattern of cell shape and protein polarization is regulated by endocytic recycling, cell identity via Dpp signaling activity, and increased tissue stress. In summary, we have demonstrated that the response of the epidermis to stretching during dorsal closure is ensured by several mechanisms, including a patterned control of cell shape and protein polarization. These mechanisms are regulated by a combination of mechanosensing and patterned cell identity.