Establishment of stably expandable induced myogenic stem cells by four transcription factors

Area of Science:

• Regenerative Medicine
• Stem Cell Biology
• Molecular Biology

Background:

• Muscle regeneration is crucial for treating degenerative muscle diseases.
• Current therapies are limited by the scarcity of healthy muscle stem cells from patients.
• A method to generate abundant, healthy myogenic stem cells is needed.

Purpose of the Study:

• To develop a method for generating healthy myogenic stem cells from fibroblasts.
• To characterize the properties of these induced myogenic stem cells (iMSCs).
• To identify molecular mechanisms underlying iMSC proliferation and differentiation.

Main Methods:

• Fibroblasts were reprogrammed into iMSCs using four transcription factors: Six1, Eya1, Esrrb, and Pax3.
• iMSCs were assessed for differentiation capacity into myotubes in vitro and in vivo.
• Cell surface markers (CD106, α7-integrin) were used to isolate enhanced iMSCs (sort-iMSCs).
• Genome-wide transcriptomic and network analyses were performed on iMSCs and sort-iMSCs.

Main Results:

• The four transcription factors successfully converted fibroblasts into iMSCs.
• iMSCs demonstrated effective differentiation into myotubes and superior proliferation compared to muscle-derived stem cells.
• iMSCs maintained proliferation capacity across multiple passages.
• sort-iMSCs exhibited enhanced myogenic differentiation.
• Transcriptomic analysis identified key genes and pathways regulating iMSC function.

Conclusions:

• Stably expandable iMSCs represent a novel and viable cell source for muscle regenerative therapy.
• iMSCs offer a new platform for drug screening in the context of muscle wasting diseases.
• This approach overcomes limitations associated with patient-derived muscle stem cells.