For the first time ever, a research study lead at Sapienza University of Rome highlighted the biological mechanism that plants use in order to differentiate stem cells. This research, published on Proceedings of the National Academy of Sciences, represents a methodological innovation in studying cellular processes and it could be extended also to human stem cells.

Plant have amazing regeneration capacities as they continuously produce new organs like roots leafs and flowers.  Thus understanding how plant control stem cell division and differentiation during organ formation could be particularly useful to collect valuable information also on human stem cell physiology.

This has been the starting point of the research group directed by Sabrina Sabatini of Sapienza University of Rome , whose four-year experimental activity led to discover a molecular mechanism necessary to activate the “transformation” process through which a plant stem cell becomes specialized.

This study principally represents a methodological innovations in stem cell research. The authors in fact developed a root mathematical model capable of accurately recreate the behaviour of this organ. They generate computational simulations by changing specific and physiological parameters thereby obtaining accurate predictions on root development and response. This model allowed to obtain information otherwise achievable only with via long and expensive experiments.

The research of the scientists focused on auxin, a compound governing organ development and growth of plants, and is therefore defined as a morphogen. A crucial role of auxin in controlling cell division was already identified; however the auxin distribution and concentration necessary to induce cell differentiation was unknown.

The model, recently developed by Sabatini and colleagues, allowed to elucidate this aspect: the scientists discovered the molecular mechanism through which the concentration and distribution of auxin – in particular the position of its minimum of concentration-  determines the position where stem cells differentiate thus acquiring specialized functions.

In Biomedicine one of the first computational model developed was on the heart: in 1928 the Dutch physicist Balthasar van der Pol developed a models simulating the heartbeat. This model was later used to study several heart defects. “We did something very similar- explains Sabatini- but in this case the layout used to run simulations is a faithful reconstruction of the root where cell/ tissues size and shape has been accurately measured and reproduced”. This allowed us to generate output at the single cell resolution.

As in plant also in humans a morphogen exist: the retinoic acids. Auxin can be considered the retinoic acids counterpart in plant. Such models could greatly contribute in understanding how such molecules control organ development.

“If a functional minimum of the retinoic acid exist has still not be proven. It would be interesting to understand if such a minimum exist and it is involved in human stem cell differentiation”, concludes Sabatini.

This is the reason why the molecular mechanism described in the article published in Proceedings of the National Academy of Sciences (PNAS) could help in the comprehensions of the molecular mechanisms that govern human stem cell activities.

References:

Auxin minimum triggers the developmental switch from cell division to cell differentiation in the Arabidopsis root. Di Mambro R, De Ruvo M, Pacifici E, Salvi E, Sozzani R, Benfey PN, Busch W, Novak O, Ljung K, Di Paola L., Marée AFM, Costantino P, Grieneisen VA, Sabatini S. Proceedings of the National Academy of Sciences 2017 Sep 5. Doi: 10.1073/pnas.1705833114.

Further Information:

Sabrina Sabatini
Department of Biology and Biotechnology Charles Darwin
Email: sabrina.sabatini@uniroma1.it