Proliferation of multiple cell types in the skeletal muscle tissue elicited by acute p21 suppression

Maria Grazia Biferi, Carmine Nicoletti, Germana Falcone, Eleonora M R Puggioni, Nunzia Passaro, Alessia Mazzola, Deborah Pajalunga, Germana Zaccagnini, Emanuele Rizzuto, Alberto Auricchio, Lorena Zentilin, Gabriele De Luca, Mauro Giacca, Fabio Martelli, Antonio Musio, Antonio Musarò, Marco Crescenzi

Research output: Contribution to journalArticlepeer-review


Although in the last decades the molecular underpinnings of the cell cycle have been unraveled, the acquired knowledge has been rarely translated into practical applications. Here, we investigate the feasibility and safety of triggering proliferation in vivo by temporary suppression of the cyclin-dependent kinase inhibitor, p21. Adeno-associated virus (AAV)-mediated, acute knockdown of p21 in intact skeletal muscles elicited proliferation of multiple, otherwise quiescent cell types, notably including satellite cells. Compared with controls, p21-suppressed muscles exhibited a striking two- to threefold expansion in cellularity and increased fiber numbers by 10 days post-transduction, with no detectable inflammation. These changes partially persisted for at least 60 days, indicating that the muscles had undergone lasting modifications. Furthermore, morphological hyperplasia was accompanied by 20% increases in maximum strength and resistance to fatigue. To assess the safety of transiently suppressing p21, cells subjected to p21 knockdown in vitro were analyzed for γ-H2AX accumulation, DNA fragmentation, cytogenetic abnormalities, ploidy, and mutations. Moreover, the differentiation competence of p21-suppressed myoblasts was investigated. These assays confirmed that transient suppression of p21 causes no genetic damage and does not impair differentiation. Our results establish the basis for further exploring the manipulation of the cell cycle as a strategy in regenerative medicine.

Original languageEnglish
Pages (from-to)885-895
Number of pages11
JournalMolecular Therapy
Issue number5
Publication statusPublished - May 9 2015

ASJC Scopus subject areas

  • Molecular Biology
  • Molecular Medicine
  • Genetics
  • Drug Discovery
  • Pharmacology


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