| First Author | Rebolledo DL | Year | 2016 |
| Journal | Hum Mol Genet | Volume | 25 |
| Issue | 1 | Pages | 158-66 |
| PubMed ID | 26604149 | Mgi Jnum | J:227695 |
| Mgi Id | MGI:5702502 | Doi | 10.1093/hmg/ddv466 |
| Citation | Rebolledo DL, et al. (2016) Sarcolemmal targeting of nNOSmu improves contractile function of mdx muscle. Hum Mol Genet 25(1):158-66 |
| abstractText | Nitric oxide (NO) is a key regulator of skeletal muscle function and metabolism, including vasoregulation, mitochondrial function, glucose uptake, fatigue and excitation-contraction coupling. The main generator of NO in skeletal muscle is the muscle-specific form of neuronal nitric oxide synthase (nNOSmu) produced by the NOS1 gene. Skeletal muscle nNOSmu is predominantly localized at the sarcolemma by interaction with the dystrophin protein complex (DPC). In Duchenne muscular dystrophy (DMD), loss of dystrophin leads to the mislocalization of nNOSmu from the sarcolemma to the cytosol. This perturbation has been shown to impair contractile function and cause muscle fatigue in dystrophic (mdx) mice. Here, we investigated the effect of restoring sarcolemmal nNOSmu on muscle contractile function in mdx mice. To achieve this, we designed a modified form of nNOSmu (NOS-M) that is targeted to the sarcolemma by palmitoylation, even in the absence of the DPC. When expressed specifically in mdx skeletal muscle, NOS-M significantly attenuates force loss owing to damaging eccentric contractions and repetitive isometric contractions (fatigue), while also improving force recovery after fatigue. Expression of unmodified nNOSmu at similar levels does not lead to sarcolemmal association and fails to improve muscle function. Aside from the benefits of sarcolemmal-localized NO production, NOS-M also increased the surface membrane levels of utrophin and other DPC proteins, including beta-dystroglycan, alpha-syntrophin and alpha-dystrobrevin in mdx muscle. These results suggest that the expression of NOS-M in skeletal muscle may be therapeutically beneficial in DMD and other muscle diseases characterized by the loss of nNOSmu from the sarcolemma. |
