Three-dimensional (3D) skeletal muscle constructs engineered from myogenic progenitors derived from human pluripotent stem cells (hPSCs) have a wide range of applications, but to date, such constructs generate lower specific tetanic force than adult human muscles. Methods enhancing functional muscle differentiation and force generation of these constructs are highly desirable. The finding of this study is that addition of the supplements in the endothelial cell growth medium-2 (EGM-2) to the myogenic differentiation medium can substantially enhance contractile force generation. For constructs differentiated for 4 weeks, addition of the EGM-2 supplements in the first 2 weeks leads to tenfold and sevenfold increases in twitch and tetanic forces, respectively. The specific tetanic force generated by these constructs is 33 mN mm−2, which is significantly higher than previously reported. These constructs show wider myotubes and higher gene expression levels for all skeletal muscle-specific myosin heavy chain isoforms, suggesting that a more mature differentiation stage of the cells underlies the greater contractile force generation. The constructs exposed to these supplements for 4 weeks do not generate as high contractile forces, suggesting that prolonged treatment is not beneficial. These results suggest that temporal conditioning with the EGM-2 supplements assists functional development of hPSC-derived skeletal muscle constructs.
Bibliographical noteFunding Information:
This work was supported by the National Science Foundation (CAREER DMR-1151529 for W.S.), by the National Institutes of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health (R01 AR055299 and R01 AR071439 for R.C.R.P.), and by the Institute for Engineering in Medicine at the University of Minnesota. The authors thank James Kiley for assistance with generation of hESC-derived myogenic progenitors and Dr. Robert T. Tranquillo and Dr. Jeremy Schaefer for the use of the contractile force measurement apparatus. The authors also thank Allison Siehr for proofreading the manuscript.
- 3D skeletal muscle tissue engineering
- EGM-2 supplements
- contractile forces
- human pluripotent stem cells