Myotube-derived exosomal miRNAs downregulate Sirtuin1 in myoblasts during muscle cell differentiation

Abstract

It has recently been established that exosomes can mediate intercellular cross-talk under normal and pathological conditions through the transfer of specific miRNAs. As muscle cells secrete exosomes, we addressed the question of whether skeletal muscle (SkM) exosomes contained specific miRNAs, and whether they could act as "endocrine signals" during myogenesis. We compared the miRNA repertoires found in exosomes released from C2C12 myoblasts and myotubes and found that 171 and 182 miRNAs were exported into exosomes from myoblasts and myotubes, respectively. Interestingly, some miRNAs were expressed at higher levels in exosomes than in their donor cells and vice versa, indicating a selectivity in the incorporation of miRNAs into exosomes. Moreover miRNAs from C2C12 exosomes were regulated during myogenesis. The predicted target genes of regulated exosomal miRNAs are mainly involved in the control of important signaling pathways for muscle cell differentiation (e.g., Wnt signaling pathway). We demonstrated that exosomes from myotubes can transfer small RNAs (C. elegans miRNAs and siRNA) into myoblasts. Moreover, we present evidence that exosome miRNAs secreted by myotubes are functionally able to silence Sirt1 in myoblasts. As Sirt1 regulates muscle gene expression and differentiation, our results show that myotube-exosome miRNAs could contribute to the commitment of myoblasts in the process of differentiation. Until now, myokines in muscle cell secretome provided a conceptual basis for communication between muscles. Here, we show that miRNA exosomal transfer would be a powerful means by which gene expression is orchestrated to regulate SkM metabolic homeostasis.

Microvesicles and exosomes: new players in metabolic and cardiovascular disease

“…The miRNA profile is different in exosomes released from C2C12 myoblasts compared with those released by C2C12 cells once they have differentiated into myotubes (Forterre et al 2014). The miRNA profile within exosomes was also found to differ from the parent C2C12 cells, which indicates that there is selective sorting of miRNA into exosomes (Forterre et al 2014).…”

“…The miRNA profile is different in exosomes released from C2C12 myoblasts compared with those released by C2C12 cells once they have differentiated into myotubes (Forterre et al 2014). The miRNA profile within exosomes was also found to differ from the parent C2C12 cells, which indicates that there is selective sorting of miRNA into exosomes (Forterre et al 2014). The mechanism for this is only beginning to be unravelled, but appears to involve recognition of particular sequence motifs by sumoylated heterogeneous nuclear ribonucleoprotein A2B1 (Villarroya-Beltri et al 2013).…”

“…The mechanism for this is only beginning to be unravelled, but appears to involve recognition of particular sequence motifs by sumoylated heterogeneous nuclear ribonucleoprotein A2B1 (Villarroya-Beltri et al 2013). When the exosomes secreted by C2C12 myotubes were taken up by myoblasts they suppressed expression of Sirt1, potentially modulating metabolic homeostasis and the commitment of myoblasts during differentiation (Forterre et al 2014).…”

Serum miRNA Signatures Are Indicative of Skeletal Fractures in Postmenopausal Women With and Without Type 2 Diabetes and Influence Osteogenic and Adipogenic Differentiation of Adipose Tissue–Derived Mesenchymal Stem Cells In Vitro

“…(22) However, to date, no data are available on the role of miRNAs in diabetic bone disease and fragility. miRNAs are generated intracellularly and actively released into the blood from various tissues (23)(24)(25) including bone, (26) making miRNAs easily accessible through peripheral blood draw. In addition, serum miRNA concentrations have been found to remain stable after blood draw at room temperature (27) making them promising biomarker candidates easily applicable in clinical routine.…”

miR-450a-5p within rat adipose tissue exosome-like vesicles promotes adipogenic differentiation by targeting WISP2

“…For example, miR-30a is a positive regulator of adipocyte lineage commitment that acts through modulation of Runx2 while miR-143 is required for terminal differentiation by modulating MAP2K5-ERK5 (ERK5 is also known as MAPK7) signaling Chen et al, 2014;Hamam et al, 2014). In addition, exosomal miRNAs also contribute to the process of cell differentiation (Forterre et al, 2014;Xu et al, 2014). Previous studies have shown that exosomes can promote differentiation of mesenchymal stem cells (MSCs) (such as osteogenesis, neurogenesis and angiogenesis) through exosomal miRNAs (Narayanan et al, 2016;Takeda and Xu, 2015;Cui et al, 2016;Lopatina et al, 2014).…”