Technique to generate new muscle cells in lab

Technique to generate new muscle cells in lab

To help patients with muscle disorders, scientists have engineered a new stem cell line to study the conversion of stem cells into muscle. Findings appeared in Cell Reports.

"We have also developed a more efficient strategy to make muscles from human stem cells. Scientists can use these cells for disease modeling, gene correction, and potential cell therapy," said the study's senior author.

Muscle disorders such as muscular dystrophy cause muscles to weaken and deteriorate, and they affect more than 50,000 people in the United States. Symptoms include difficulty walking and standing. In severe cases, the disorders might involve cardiac and respiratory muscles and lead to death. There is no cure.

The team engineered a novel human stem cell line for skeletal muscle. To ensure the purity of the muscle stem cells, they tagged muscle genes (PAX7, MYF5) with two fluorescent proteins. "In order to improve the formation of the muscle from stem cells, we screened several bioactive compounds. The surface marker screen allowed identification of CD10 and CD24 for purification of myogenic progenitors and exclusion of non-myogenic cells. CD10 expression was also identified on human satellite cells and skeletal muscle progenitors. We were also able to observe muscle stem cell activity in great detail using color tags," the author said.. 

The stem cells were generated from a patient's skin cells and used to generate muscle. The team's "approach also allowed induction and purification of skeletal myogenic progenitors in a much shorter time course (2 weeks) with considerable in vitro and in vivo myogenic potential (myofiber engraftment and satellite cell seeding)," the authors wrote.

The modified stem cells produced promising results in a culture of human tissue, as well as in a mouse model of Duchenne muscular dystrophy. In vitro and in vivo studies using transgene and/or reporter-free hPSCs further validated myogenic potential of the cells by formation of new fibers expressing human dystrophin as well as donor-derived satellite cells in NSG-mdx4Cv mice. "In a side-by-side comparison with previous strategies, our strategy allowed faster and more efficient generation of muscle stem cells with superior engraftment in mice," the author said said.