title: SIRT3, a mitochondrial NAD⁺-dependent deacetylase, is involved in the regulation of myoblast differentiation.
abstract: Sirtuin 3 (SIRT3), one of the seven mammalian sirtuins, is a mitochondrial NAD+-dependent deacetylase known to control key metabolic pathways. SIRT3 deacetylases and activates a large number of mitochondrial enzymes involved in the respiratory chain, in ATP production, and in both the citric acid and urea cycles. We have previously shown that the regulation of myoblast differentiation is tightly linked to mitochondrial activity. Since SIRT3 modulates mitochondrial activity, we decide to address its role during myoblast differentiation. For this purpose, we first investigated the expression of endogenous SIRT3 during C2C12 myoblast differentiation. We further studied the impact of SIRT3 silencing on both the myogenic potential and the mitochondrial activity of C2C12 cells. We showed that SIRT3 protein expression peaked at the onset of myoblast differentiation. The inhibition of SIRT3 expression mediated by the stable integration of SIRT3 short inhibitory RNA (SIRT3shRNA) in C2C12 myoblasts, resulted in: 1) abrogation of terminal differentiation - as evidenced by a marked decrease in the myoblast fusion index and a significant reduction of Myogenin, MyoD, Sirtuin 1 and Troponin T protein expression - restored upon MyoD overexpression; 2) a decrease in peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and citrate synthase protein expression reflecting an alteration of mitochondrial density; and 3) an increased production of reactive oxygen species (ROS) mirrored by the decreased activity of manganese superoxide dismutase (MnSOD). Altogether our data demonstrate that SIRT3 mainly regulates myoblast differentiation via its influence on mitochondrial activity.
authors.affiliation: INRA, UMR866 Dynamique Musculaire et Métabolisme, F-34060 Montpellier - Université Montpellier 1, F-34000 Montpellier - Université Montpellier 2, Montpellier, France.
authors.forename: Waed
authors.initials: W
authors.lastname: Abdel Khalek
authors.affiliation: INRA, UMR866 Dynamique Musculaire et Métabolisme, F-34060 Montpellier - Université Montpellier 1, F-34000 Montpellier - Université Montpellier 2, Montpellier, France.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Cortade
authors.affiliation: INRA, UMR866 Dynamique Musculaire et Métabolisme, F-34060 Montpellier - Université Montpellier 1, F-34000 Montpellier - Université Montpellier 2, Montpellier, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Ollendorff
authors.affiliation: IGMM, Institut de Génétique Moléculaire de Montpellier, CNRS-UMR5535, Montpellier France - Université Montpellier 1, F-34000 Montpellier - Université Montpellier 2, Montpellier, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Lapasset
authors.affiliation: INRA, UMR866 Dynamique Musculaire et Métabolisme, F-34060 Montpellier - Université Montpellier 1, F-34000 Montpellier - Université Montpellier 2, Montpellier, France; Biozentrum, University of Basel, Basel, Switzerland.
authors.forename: Lionel
authors.initials: L
authors.lastname: Tintignac
authors.affiliation: INRA, UMR866 Dynamique Musculaire et Métabolisme, F-34060 Montpellier - Université Montpellier 1, F-34000 Montpellier - Université Montpellier 2, Montpellier, France.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Chabi
authors.affiliation: INRA, UMR866 Dynamique Musculaire et Métabolisme, F-34060 Montpellier - Université Montpellier 1, F-34000 Montpellier - Université Montpellier 2, Montpellier, France.
authors.forename: Chantal
authors.initials: C
authors.lastname: Wrutniak-Cabello
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D015536:Down-Regulation; D055785:Gene Knockdown Techniques; D051379:Mice; D008928:Mitochondria / Q000201:enzymology* / Q000378:metabolism; D017570:MyoD Protein / Q000235:genetics; D032446:Myoblasts / Q000166:cytology*; D009243:NAD / Q000378:metabolism*; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D056566:Sirtuin 3 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D017570:MyoD Protein; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C485290:Ppargc1a protein, mouse; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D014157:Transcription Factors; D009243:NAD; D056566:Sirtuin 3