American researchers have investigated whether the supply of microdystrophin via AAV viruses could modify the physiological overexpression of utrophin observed in Duchenne muscular dystrophy:
- the double-knockout mouse for utrophin and dystrophin (dKO) served as an experimental model, and received a transgene encoding utrophin,
- in addition, two distinct types of micro-dystrophin (mDysH3 and mDys5) were injected into the same mouse at low doses,
- under these conditions, utrophin and the truncated version of dystrophin are expressed at the muscle fiber membrane, stabilizing the dystrophin-associated protein complex.
The researchers conclude that therapeutic microdystrophin does not compete with utrophin.
