From Duke University Medical Center, USA

will give a seminar entitled :

Listening to the scale-beat: Erk activity waves in zebrafish scale regeneration

Abstract :

I am interested in understanding the physical principles underlying the organization of regeneration, the spectacular process in which a lost body part regrows to its original size and shape. Regeneration poses fundamental questions regarding how cell behaviours are organized over large spatial distances and long time, to recover a tissue of the right form, starting from variable injuries. I believe that addressing these questions requires a quantitative, interdisciplinary approach. Specifically, it requires combining a tractable system with live imaging, ideally performed in the native context. In this process, theoretical ideas will be key to conceptualize the interplay of signals and cell behaviours. During my postdoctoral work, I developed a quantitative approach to study signals in regeneration using the zebrafish scale as a model system, a simple bone disk amenable to live imaging. I discovered concentric traveling waves of Erk activity, broadcasted from a central source, that instruct hypertrophic growth of the regenerating osteoblast tissue. Using a combination of theoretical and experimental analyses, we find that Erk activity propagates as an excitable wave and traverses the entire millimetre-sized scale in approximately two days. Erk activity waves induce patterned tissue expansion and the frequency of wave generation controls the rate of scale growth.  Our findings reveal trigger waves broadcasted from a central source as a regulatory strategy to coordinate regeneration. In my future research, I will leverage on this platform to investigate how chemical and mechanical cues are tuned and integrated to orchestrate morphogenesis in regeneration.