title: Adult stem cell plasticity: neoblast repopulation in non-lethally irradiated planarians.
abstract: Planarians are a model system for studying adult stem cells, as they possess the neoblasts, a population of pluripotent adult stem cells able to give rise to both somatic and germ cells. Although over the last years several efforts have been made to shed light on neoblast biology, only recent evidence indicate that this population of cells is heterogeneous. In this study we irradiated planarians with different non-lethal X-ray doses (1-5 Gy) and we identified subpopulations of neoblasts with diverse levels of tolerance to X-rays. We demonstrated that a dramatic reduction of neoblasts occurred soon after non-lethal irradiations and that de-novo proliferation of some radioresistant cells re-established the primary neoblast number. In particular, a strong proliferation activity occurred at the ventral side of irradiated animals close to the nervous system. The produced cells migrated towards the dorsal parenchyma and, together with some dorsal radioresistant cells, reconstituted the entire neoblast population demonstrating the extreme plasticity of this adult stem cell system.
authors.affiliation: Dipartimento di Morfologia Umana e Biologia Applicata, Università di Pisa, Pisa, Italy. a.salvetti@biomed.unipi.it
authors.forename: Alessandra
authors.initials: A
authors.lastname: Salvetti
authors.forename: Leonardo
authors.initials: L
authors.lastname: Rossi
authors.forename: Lucia
authors.initials: L
authors.lastname: Bonuccelli
authors.forename: Annalisa
authors.initials: A
authors.lastname: Lena
authors.forename: Claudio
authors.initials: C
authors.lastname: Pugliesi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Rainaldi
authors.forename: Monica
authors.initials: M
authors.lastname: Evangelista
authors.forename: Vittorio
authors.initials: V
authors.lastname: Gremigni
mesh_terms: D053687:Adult Stem Cells / Q000166:cytology* / Q000502:physiology; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology / Q000528:radiation effects; D002465:Cell Movement / Q000502:physiology / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects*; D010932:Planarians / Q000166:cytology* / Q000528:radiation effects