Freshwater planarians (Platyhelminthes) possess remarkably powerful regenerative capabilities: they can regenerate a complete animal from a tiny piece of their bodies. Since this ability was reported already in 1766 by Pallas, scientists have been attracted to the study of these animals, considered to be “immortal under the edge of the knife” (Dalyell, 1814). Planarian regeneration depends upon the existence of a population of totipotent stem cells, called neoblasts. My main research interest is focussed on:

The influence of the nervous system on planarian regeneration
A key question to answer in the field of planarian regeneration is how are the neoblasts instructed to differentiate into the missing structures. After cutting, neoblasts proliferate, differentiate into any cell type and restore the original pattern of the amputated part. Several studies have suggested that the nervous system may play an important role in the regenerative process. However, most of the evidence is indirect and we don’t know yet which signals coming from the nervous system may be regulating important aspects such as cell proliferation, migration, differentiation and pattern formation. The main goal of this project is to characterize such signals and their functions during planarian regeneration.

Recently, it has been shown that RNAi knockdowns of Smed-roboA (a planarian homologue of the axon guidance family of Robo receptors) result in morphogenesis defects such as the differentiation of ectopic pharynges and cephalic outgrowths. These defects are associated with an abnormal regeneration of the central nervous system (CNS) in the treated animals. By using proteomics it should be possible to identify any signal coming from the truncated CNS of Smed-roboA RNAi animals that could be responsible for this differentiation of ectopic structures. A second approach to the study of the influence of the nervous system on regeneration is based on the isolation of planarian homologues of a variety of neurotransmitters, neuropeptides and growth factors and their posterior functional characterization. Thanks to the data obtained from a Genome sequencing project in Schmidtea mediterranea, many homologues of these factors have been already characterized “in silico”, and represent the starting point of this part of the project.