Watching Stem Cells in Action

Some stem cells give rise to hundreds of daughter cells, and other stem cells barely ever divide. Why?

Novel mouse models and live imaging techniques have made it possible to record, while the mice are sleeping, what’s happening for example in their skin. The combination of these methods allows answering questions that scientists have asked for decades: how is the growth and maintenance of a healthy organ coordinated?

Valentina Greco (Assistant Professor at Yale University) and her team recorded how the stem cells, which are the cells responsible for the constant supply of new cells to maintain an organ, stay silent or get activated. An excellent model system for studying this stem cell dynamics is the hair follicle in the skin, since hair follicles are self-maintaining mini-organs and skin is easily accessible for microscopy.

Due to our newly launched seminar series called ‘Science and Career BioNuTalks’ at the Department for Biosciences and Nutrition (BioNut, Karolinska Institutet), I invited Valentina to give a seminar and to spend a day at our Department discussing science with colleagues, my team and me.

The presentation was fantastic! Seeing the stem cells move, and seeing what they do during tissue renewal, is stunning! Her new data show that the actions stem cells take is highly dependent on the so-called microenvironment, the location where a stem cell resides. If a stem cell happens to change its location to a new place (e.g.: leaves the place where it is kept silent) – which can be just a few cell diameters away from the original place – this stem cell takes on a new task and now for example can contribute in active organ growth. These new insights – using live in-vivo microscopy – opens up a new horizon for a more general understanding of how organs can be maintained, and also emphasizes that the immediate microenvironment is crucial for stem cell behavior.

It was a truly inspiring day!


References to the work
Rompolas P, Mesa KR, Greco V. Spatial organization within a niche as a determinant of stem-cell fate. Nature. 2013 Oct 6. doi: 10.1038/nature12602.

Rompolas P, Deschene ER, Zito G, Gonzalez DG, Saotome I, Haberman AM, Greco V. Live imaging of stem cell and progeny behaviour in physiological hair-follicle regeneration. Nature. 2012 Jul 26;487(7408):496-9. doi: 10.1038/nature11218.