Inhibition of the Combinatorial Signaling of Transforming Growth Factor-Beta and NOTCH Promotes Myotube Formation of Human Pluripotent Stem Cell-Derived Skeletal Muscle Progenitor Cells

Abstract

Understanding the signaling pathways that regulate the final differentiation of human myoblasts is essential for successful cell transplantation and drug screening for the treatment of muscular dystrophy. In an effort to improve myotube formation from hiPSC-derived myoblasts, we validated a collection of 13 small molecules in a newly established in vitro screening platform for the assessment of myotube formation. The analysis of myotube formation as measured by the fusion index showed that the combinational inhibition of the TGFβ signaling with NOTCH signaling enhances the ability of multi-nucleated myotube production. Combinational treatment of inhibitors for TGFβ and NOTCH signaling pathways improved myotube formation in a dose-dependent manner. This effect was achieved by inhibiting the combinatorial mechanism of signaling. The combination treatment of small molecules effective in inducing multinucleated myotubes was validated in healthy human primary myoblasts. In addition, it was also applied to DMD patient iPSC-derived myoblasts to enhance the generation of multinucleated myotubes.

Osteohematology: To be or Notch to be

“…and HEYL) (Figure 2b) (Schroeter et al, 1998). The canonical pathway displays critical roles in many cellular functions, in particularly stem cell proliferation, differentiation, cell death, somite segmentation, angiogenesis, and vascular development (AlMuraikhi et al, 2019;Chen et al, 2014;Choi et al, 2021).…”

“…This complex induces the transcription of downstream target genes, including, basic helix‐loop‐helix family transcription factors: hairy enhancer of split family genes (HES1, HES5, and HES7) and HES‐related with YRPF motif genes of the family (HEY1, HEY2, and HEYL) (Figure 2b) (Schroeter et al, 1998). The canonical pathway displays critical roles in many cellular functions, in particularly stem cell proliferation, differentiation, cell death, somite segmentation, angiogenesis, and vascular development (AlMuraikhi et al, 2019; Chen et al, 2014; Choi et al, 2021).…”

The Notch signaling pathway in skeletal muscle health and disease

“…There is also emerging evidence that the Notch signaling pathway is a promising target for therapy in skeletal muscle. Specific small molecule candidate drugs have been found to promote human myotube formation, 165 and sertraline has been found to ameliorate MEGF10 myopathy in cellular, Drosophila , and zebrafish model systems. 54 …”

Implications of notch signaling in duchenne muscular dystrophy

“…Therefore, up-regulation of Jag1 by IL-1β plays a crucial role in the loss of muscle regeneration capacity of DMD muscles ( Table 2 ; Nagata et al, 2017 ). Finally, inhibition of Notch and TGF-β promotes myogenic differentiation of human DMD-derived induced Pluripotent Stem Cells (iPSCs) ( Table 2 ; Choi et al, 2012 ). With respect to muscular dystrophy treatment, the opposite approach would likely be taken, attempting to increase Notch activity rather than decrease it as is done in cancer treatments.…”