Apoptosis is a mechanism of eliminating damaged or unnecessary cells during development and tissue homeostasis. During apoptosis within a tissue, the adhesions between dying and neighboring non-dying cells need to be remodeled so that the apoptotic cell is expelled. In parallel, contraction of actomyosin cables formed in apoptotic and neighboring cells drives cell extrusion. To date, the coordination between the dynamics of cell adhesion and the progressive changes in tissue tension around an apoptotic cell is not fully understood. Live imaging of histoblast expansion, which is a coordinated tissue replacement process during Drosophila metamorphosis, shows remodeling of adherens junctions (AJs) between apoptotic and non-dying cells, with a reduction in the levels of AJ components, including E-cadherin. Concurrently, surrounding tissue tension is transiently released. Contraction of a supra-cellular actomyosin cable, which forms in neighboring cells, brings neighboring cells together and further reshapes tissue tension toward the completion of extrusion. We propose a model in which modulation of tissue tension represents a mechanism of apoptotic cell extrusion.
The authors declare no competing or financial interests.
X.T. and Y.T. designed the research and prepared the manuscript. X.T., R.L.B., and Y.T. edited the manuscript. X.T., R.L.B., and Y.T. performed the experiments and analyses. L.Q. contributed new reagents. Y.T. oversaw the project.
This work was supported by an NUS Research Scholarship from the National University of Singapore (to X.T.); Mechanobiology Institute, Singapore and National University of Singapore Startup Grants (to Y.T.); Temasek Life Sciences Laboratory (Y.T.); and a Ministry of Education - Singapore Tier 2 grant (MOE2015-T2-1-116 to Y.T.). R.L.B. and Y.T. were supported by the PHC Merlion Programme no. 5.14.13 of the Institut Français de Singapour, under administrative supervision of the Ministère des Affaires Étrangères, and the National University of Singapore.
Supplementary information available online at http://dev.biologists.org/lookup/doi/10.1242/dev.139865.supplemental
- Received May 18, 2016.
- Accepted November 10, 2016.