Cell polarity and extrusion: how to polarize extrusion and extrude misspolarized cells?

Ralitza Staneva (1, 2) , Romain Levayer (1, 2)

1 Département de Biologie du Développement et Cellules souches - Department of Developmental and Stem Cell Biology
2 CNRS UMR3738 - Biologie du Développement et Cellules souches (Département)

The barrier function of epithelia is one of the cornerstones of the body plan organisation of metazoans. It relies on the polarity of epithelial cells which organises along the apico-basal axis the mechanical properties, signalling as well as transport. This barrier function is however constantly challenged by the fast turnover of epithelia occurring during morphogenesis or adult tissue homeostasis. Yet, the sealing property of the tissue can be maintained thanks to cell extrusion: a series of remodelling steps involving the dying cell and its neighbours leading to seamless cell expulsion. Alternatively, the tissue architecture can also be challenged by local damages or the emergence of mutant cells that may alter its organisation. This includes mutants of the polarity complexes which can generate neoplastic overgrowths or be eliminated by cell competition when surrounded by wild type cells. In this review, we will provide an overview of the regulation of cell extrusion in various tissues focusing on the relationship between cell polarity, cell organisation and the direction of cell expulsion. We will then describe how local perturbations of polarity can also trigger cell elimination either by apoptosis or by cell exclusion, focusing specifically on how polarity defects can be directly causal to cell elimination. Overall, we propose a general framework connecting the influence of polarity on cell extrusion and its contribution to aberrant cell elimination.

Mots clés: cell extrusion; apico-basal polarity; cell competition; epithelium; cell death; planar cell polarity

Domaines: Sciences du Vivant [q-bio]

Ralitza Staneva, Romain Levayer. Cell polarity and extrusion: how to polarize extrusion and extrude misspolarized cells?. Current Topics in Developmental Biology, 2023, 154, pp.131-167. ⟨10.1016/bs.ctdb.2023.02.010⟩. ⟨pasteur-04143465⟩