The specification of skeletal muscle cells starting from totipotent stem cells lies at the core of skeletal myogenesis. During this process, the genome of the progenitor muscle cells is modified to ensure that stable- if not irreversible- distinctions are made between genes not to b expressed from genes whose expression is or will be required. MyoD is a transcriptional activator required for muscle-specific gene expression. Expression of exogenous MyoD in numerous terminally differentiated cell lineages ( neurons, adipocytes, skin cells, chondrocytes and others) redirect their fates towards the skeletal muscle phenotype. Furthermore, MyoD - and the related Myf-5 protein- is essential for the formation of skeletal muscles in the animal. In order to regulate transcription, MyoD recruits chromatin and histone modifying enzymes. Specification and maintenance of committed, yet undifferentiated, muscle precursors is the result of a fine balance between gene activation and repression. Genes to be expressed in terminally differentiated cells, are actively repressed in muscle precursors. Ezh2, the subunit conferring methyltransferase activity to the Polycomb Repressive Complex 2(PRC2) occupies and methylates histone located at regulatory regions of muscle-specific genes not expressed in muscle precursors. Once differentation ensues, Ezh2 binding is lost and histone methylation is erased resulting in transcriptional activation. In addition to methylation-demethylation, other histone modifications are associated with muscle gene expression. Acetylation and deacetylation are in a dynamic equilibrium and our studies have identified a role for several histone deacetylases (HDACs) in controlling muscle differentiation. We have used small molecules to modulate the enzymatic activity of several HDACs in skeletal muscle cells. Pharmacological modulation of the HDACs was found to ameliorate the morphology and function of mouse dystrophic muscles. With the aim of contributing to a better understanding of the mechanisms that regulate gene expression in physiological and pathological conditions, we will continue to identify and functionally characterize molecules that cause histone and chromatin modifications and regulate proliferation, differentiation, and regeneration of skeletal muscle cells.

Project Start
Project End
Budget Start
Budget End
Support Year
8
Fiscal Year
2007
Total Cost
$1,415,211
Indirect Cost
Name
National Institute of Arthritis and Musculoskeletal and Skin Diseases
Department
Type
DUNS #
City
State
Country
United States
Zip Code
Sartorelli, Vittorio; Puri, Pier Lorenzo (2018) Shaping Gene Expression by Landscaping Chromatin Architecture: Lessons from a Master. Mol Cell 71:375-388
Puri, Pier Lorenzo; Sartorelli, Vittorio (2010) HDACs and sirtuins: targets for new pharmacological interventions in human diseases. Pharmacol Res 62:1-2
Juan, Aster H; Kumar, Roshan M; Marx, Joseph G et al. (2009) Mir-214-dependent regulation of the polycomb protein Ezh2 in skeletal muscle and embryonic stem cells. Mol Cell 36:61-74
Fulco, Marcella; Cen, Yana; Zhao, Po et al. (2008) Glucose restriction inhibits skeletal myoblast differentiation by activating SIRT1 through AMPK-mediated regulation of Nampt. Dev Cell 14:661-73
Fulco, Marcella; Sartorelli, Vittorio (2008) Comparing and contrasting the roles of AMPK and SIRT1 in metabolic tissues. Cell Cycle 7:3669-79
Di Padova, Monica; Caretti, Giuseppina; Zhao, Po et al. (2007) MyoD acetylation influences temporal patterns of skeletal muscle gene expression. J Biol Chem 282:37650-9
Caretti, Giuseppina; Lei, Elissa P; Sartorelli, Vittorio (2007) The DEAD-box p68/p72 proteins and the noncoding RNA steroid receptor activator SRA: eclectic regulators of disparate biological functions. Cell Cycle 6:1172-6
Bakay, Marina; Wang, Zuyi; Melcon, Gisela et al. (2006) Nuclear envelope dystrophies show a transcriptional fingerprint suggesting disruption of Rb-MyoD pathways in muscle regeneration. Brain 129:996-1013
Minetti, G C; Colussi, C; Adami, R et al. (2006) Functional and morphological recovery of dystrophic muscles in mice treated with deacetylase inhibitors. Nat Med 12:1147-50
Zhao, Po; Caretti, Giuseppina; Mitchell, Stephanie et al. (2006) Fgfr4 is required for effective muscle regeneration in vivo. Delineation of a MyoD-Tead2-Fgfr4 transcriptional pathway. J Biol Chem 281:429-38

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