Institut Jacques Monod Seminar – Stéphanie Ellis

Invited by the Ladoux/Mege, Stéphanie Ellis (Max Perutz Labs/University of Vienna/Vienna Biocenter Campus) will present an Institut Jacques Monod on the theme:

Understanding mosaic tissue dynamics through cell competition.

Abstract:

What are the cellular principles of growth control in complex tissues as they grow, differentiate, reach their final size, and contend with threats to their homeostasis? In the Ellis Lab, we study this question through the lens of cell competition, a conserved, yet poorly understood, phenomenon of growth control. Cell competition is likely to have serious implications for heterogeneous cell-cell interactions within tissues during development, homeostasis, and in disease. Research in my group explores the molecular and cellular mechanisms that underlie competitive behaviours and their consequences for establishing and maintaining robust tissue function across distinct physiological states. We recently established the murine skin epidermis as a physiologically-relevant, genetically tractable model for the study of cell competition in mammals. In my talk, I will summarize our ongoing efforts to probe the molecular and cellular mechanisms of cell competition and fitness sensing in three specific contexts: 1- normal development; 2- tumour initiation; 3- X-linked inflammatory disease. Using a combination of genetic and genomic approaches, lineage tracing, time-lapse microscopy, functional assays, and disease models we have uncovered evidence suggesting that skin barrier function critically depends on cell competition. Intriguingly, we find that the strategy the skin uses to eliminate less fit cells undergoes a transition as tissue architecture becomes more complex during morphogenesis, and that this may also be linked to changes in tissue mechanics. Based on our preliminary data, we propose that cell competition maintains homeostasis and optimises organ function by shaping tissue-level responses to stresses that are inevitably encountered over long, unpredictable lifetimes.