Mesodermal iPSC–derived progenitor cells functionally regenerate cardiac and skeletal muscle

Abstract

Conditions such as muscular dystrophies (MDs) that affect both cardiac and skeletal muscles would benefit from therapeutic strategies that enable regeneration of both of these striated muscle types. Protocols have been developed to promote induced pluripotent stem cells (iPSCs) to differentiate toward cardiac or skeletal muscle; however, there are currently no strategies to simultaneously target both muscle types. Tissues exhibit specific epigenetic alterations; therefore, source-related lineage biases have the potential to improve iPSC-driven multilineage differentiation. Here, we determined that differential myogenic propensity influences the commitment of isogenic iPSCs and a specifically isolated pool of mesodermal iPSC-derived progenitors (MiPs) toward the striated muscle lineages. Differential myogenic propensity did not influence pluripotency, but did selectively enhance chimerism of MiP-derived tissue in both fetal and adult skeletal muscle. When injected into dystrophic mice, MiPs engrafted and repaired both skeletal and cardiac muscle, reducing functional defects. Similarly, engraftment into dystrophic mice of canine MiPs from dystrophic dogs that had undergone TALEN-mediated correction of the MD-associated mutation also resulted in functional striatal muscle regeneration. Moreover, human MiPs exhibited the same capacity for the dual differentiation observed in murine and canine MiPs. The findings of this study suggest that MiPs should be further explored for combined therapy of cardiac and skeletal muscles.

Intermittent glucocorticoid steroid dosing enhances muscle repair without eliciting muscle atrophy

“…Immediately before sacrifice, in situ tetanic force from tibialis anterior muscle was measured using a Whole Mouse Test System (catalog 1300A, Aurora Scientific) with a 1 N dual-action lever arm force transducer (300C-LR, Aurora Scientific) in anesthetized animals (3% isoflurane in 100% O 2 ). Tetanic isometric contraction was induced with the following specifications: initial delay, 0.1 seconds; frequency, 200 Hz; pulse width, 0.5 msec; duration, 0.5 seconds; using 100 mA stimulation (59). Length was adjusted to a fixed baseline of 30 mN resting tension for all muscles/conditions.…”

“…ChIP-qPCR and luciferase assays. ChIP-qPCR was performed according to a previously reported protocol (64) and adjusted conditions (59). Results were expressed as percentages of raw expression of the respective input.…”

Striated muscle function, regeneration, and repair

“…Furthermore, these cells proliferate extensively in vitro and can be genetically modified making them an attractive cell source for treatment of congenital myopathies such as muscular dystrophy [124–126]. Additionally, iPSCs derived from mesoangioblasts fuse more efficiently with skeletal muscle compared to iPSCs derived from fibroblasts suggesting the mesoangioblasts may be a more ideal source from which to generate iPSC-derived myogenic progenitors [127]. To date, all published work with mesoangioblasts and pericytes has been preclinical, being performed in mice and dogs, and it is currently unclear if this promising cell therapy approach will translate to humans and be clinically feasible.…”

Morphological and functional analyses of skeletal muscles from an immunodeficient animal model of limb‐girdle muscular dystrophy type 2E

“…A large portion of the mixed cell populations obtained from 1‐ and 7‐month‐old animals was processed by flourescence‐activated cell sorting (FACS) analysis for sorting alkaline phosphate‐positive (AP + ) fractions, and a small portion was plated onto collagen‐coated Petri dishes and incubated (37 °C in a 5% CO 2 , 5% O 2 humidified incubator) for further characterization. AP was used as a specific marker to sort pure MAB populations, as previously described . MABs, as an AP + cell fraction, were cultured and expanded on collagen‐coated plastic in Dulbecco's modified Eagle medium‐20 (DMEM‐20) culture medium (DMEM high glucose, 20% fetal calf serum [FCS], 1% penicillin/streptomycin solution [100 units], 2 mmol/L glutamine, 1 mmol/L sodium pyruvate, 1 × nonessential amino acid solution, 0.5% β‐mercaptoethanol).…”