SETDB1 modulates the TGFbeta response in Duchenne muscular dystrophy myotubes
Overactivation of the TGF{beta} signaling in Duchenne muscular dystrophy (DMD) is a major hallmark of disease progression, leading to fibrosis and muscle dysfunction. Here, we investigated the role of SETDB1, a histone lysine methyltransferase involved in muscle differentiation. Our data show that, following TGF{beta} induction, SETDB1 accumulates in the nuclei of healthy myotubes, while being already present in the nuclei of DMD myotubes where TGF{beta} signaling is constitutively activated. Interestingly, transcriptomics revealed that depletion of SETDB1 in DMD myotubes leads to downregulation of TGF{beta}-target genes coding for secreted factors involved in extracellular matrix remodeling and inflammation. Consequently, SETDB1 silencing in DMD myotubes abrogates the deleterious effect of their secretome on myoblast differentiation by impairing myoblast pro-fibrotic response. Our findings indicate that SETDB1 potentiates the TGF{beta}-driven fibrotic response in DMD muscles, providing a new axis for therapeutic intervention. Key resultsO_LITGF{beta} induces nuclear accumulation of SETDB1 in healthy myotubes C_LIO_LISETDB1 is enriched in DMD myotube nuclei with intrinsic TGF{beta} pathway overactivation C_LIO_LISETDB1 LOF in DMD myotubes attenuates TGF{beta}-induced pro-fibrotic response C_LIO_LISecretome of TGF{beta}-treated DMD myotubes with SETDB1 LOF is less deleterious on myoblast differentiation C_LI