title: Retinoic acid maintains human skeletal muscle progenitor cells in an immature state.
abstract: Muscle satellite cells are resistant to cytotoxic agents, and they express several genes that confer resistance to stress, thus allowing efficient dystrophic muscle regeneration after transplantation. However, once they are activated, this capacity to resist to aggressive agents is diminished resulting in massive death of transplanted cells. Although cell immaturity represents a survival advantage, the signalling pathways involved in the control of the immature state remain to be explored. Here, we show that incubation of human myoblasts with retinoic acid impairs skeletal muscle differentiation through activation of the retinoic-acid receptor family of nuclear receptor. Conversely, pharmacologic or genetic inactivation of endogenous retinoic-acid receptors improved myoblast differentiation. Retinoic acid inhibits the expression of early and late muscle differentiation markers and enhances the expression of myogenic specification genes, such as PAX7 and PAX3. These results suggest that the retinoic-acid-signalling pathway might maintain myoblasts in an undifferentiated/immature stage. To determine the relevance of these observations, we characterised the retinoic-acid-signalling pathways in freshly isolated satellite cells in mice and in siMYOD immature human myoblasts. Our analysis reveals that the immature state of muscle progenitors is correlated with high expression of several genes of the retinoic-acid-signalling pathway both in mice and in human. Taken together, our data provide evidences for an important role of the retinoic-acid-signalling pathway in the regulation of the immature state of muscle progenitors.
authors.affiliation: Inserm U1046-UMR CNRS 9214 «Physiologie et Médecine Expérimentale du cœur et des muscles-PHYMEDEXP», CHU A. De Villeneuve, Université de Montpellier, Bâtiment Crastes de Paulet, 371 avenue du doyen Giraud, 34295, Montpellier Cedex 5, France.
authors.forename: Marina
authors.initials: M
authors.lastname: El Haddad
authors.affiliation: Inserm U1046-UMR CNRS 9214 «Physiologie et Médecine Expérimentale du cœur et des muscles-PHYMEDEXP», CHU A. De Villeneuve, Université de Montpellier, Bâtiment Crastes de Paulet, 371 avenue du doyen Giraud, 34295, Montpellier Cedex 5, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Notarnicola
authors.affiliation: Stem Cells and Development, CNRS URA 2578, Department of Developmental and Stem Cell Biology, Pasteur Institute, 25 rue du Dr Roux, 75015, Paris, France.
authors.forename: Brendan
authors.initials: B
authors.lastname: Evano
authors.affiliation: Inserm U1046-UMR CNRS 9214 «Physiologie et Médecine Expérimentale du cœur et des muscles-PHYMEDEXP», CHU A. De Villeneuve, Université de Montpellier, Bâtiment Crastes de Paulet, 371 avenue du doyen Giraud, 34295, Montpellier Cedex 5, France.
authors.forename: Nour
authors.initials: N
authors.lastname: El Khatib
authors.affiliation: Inserm U1046-UMR CNRS 9214 «Physiologie et Médecine Expérimentale du cœur et des muscles-PHYMEDEXP», CHU A. De Villeneuve, Université de Montpellier, Bâtiment Crastes de Paulet, 371 avenue du doyen Giraud, 34295, Montpellier Cedex 5, France.
authors.forename: Marine
authors.initials: M
authors.lastname: Blaquière
authors.affiliation: INRA, UMR866, Dynamique Musculaire et Métabolisme, Université Montpellier, 34060, Montpellier, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Bonnieu
authors.affiliation: Stem Cells and Development, CNRS URA 2578, Department of Developmental and Stem Cell Biology, Pasteur Institute, 25 rue du Dr Roux, 75015, Paris, France.
authors.forename: Shahragim
authors.initials: S
authors.lastname: Tajbakhsh
authors.affiliation: Inserm U1046-UMR CNRS 9214 «Physiologie et Médecine Expérimentale du cœur et des muscles-PHYMEDEXP», CHU A. De Villeneuve, Université de Montpellier, Bâtiment Crastes de Paulet, 371 avenue du doyen Giraud, 34295, Montpellier Cedex 5, France.
authors.forename: Gérald
authors.initials: G
authors.lastname: Hugon
authors.affiliation: INRA, UMR866, Dynamique Musculaire et Métabolisme, Université Montpellier, 34060, Montpellier, France.
authors.forename: Barbara
authors.initials: B
authors.lastname: Vernus
authors.affiliation: Inserm U1046-UMR CNRS 9214 «Physiologie et Médecine Expérimentale du cœur et des muscles-PHYMEDEXP», CHU A. De Villeneuve, Université de Montpellier, Bâtiment Crastes de Paulet, 371 avenue du doyen Giraud, 34295, Montpellier Cedex 5, France.|Département de Physiologie Clinique, CHRU de Montpellier, 34295, Montpellier Cedex 5, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Mercier
authors.affiliation: Inserm U1046-UMR CNRS 9214 «Physiologie et Médecine Expérimentale du cœur et des muscles-PHYMEDEXP», CHU A. De Villeneuve, Université de Montpellier, Bâtiment Crastes de Paulet, 371 avenue du doyen Giraud, 34295, Montpellier Cedex 5, France. gilles.carnac@inserm.fr.
authors.forename: Gilles
authors.initials: G
authors.lastname: Carnac
mesh_terms: D000328:Adult; D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D008297:Male; D051379:Mice; D024510:Muscle Development; D017570:MyoD Protein / Q000235:genetics / Q000378:metabolism; D032446:Myoblasts / Q000166:cytology* / Q000378:metabolism*; D034622:RNA Interference; D018168:Receptors, Retinoic Acid / Q000378:metabolism; D015398:Signal Transduction; D014212:Tretinoin / Q000378:metabolism*
chemical_list: D017570:MyoD Protein; C057363:MyoD1 myogenic differentiation protein; D018168:Receptors, Retinoic Acid; D014212:Tretinoin
keywords: Differentiation; MyoD; Myoblasts; RAR; Satellite cells