Short hairpin RNA treatment improves gait in a mouse model of Charcot­Marie­Tooth disease type 1A.

ABSTRACT

Charcot­Marie­Tooth disease (CMT) is the most common inherited neurological disorder of the peripheral nervous system. The major subtype, CMT type 1A (CMT1A), accounts for ~40% of CMT cases and is characterized by distal muscle atrophy and gait disturbances. Short hairpin (sh) RNA sequences are potentially advantageous therapeutic tools for distal muscle atrophy­induced gait disturbance. Therefore, the current study focused on the effects of an optimal shRNA injection using the myostatin (mstn) gene inhibition system. shLenti­Mstn A demonstrated significant suppression of endogenous mstn gene expression (>40%) via RT­qPCR following direct injection into the gastrocnemius and rectus femoris of the hind limb in C22 mice. The results also reported that shLenti­Mstn A treatment increased muscle mass and size of the hind limbs compared with mock­treated mice via measurement of the mass of injected muscles and magnetic resonance imaging study. Furthermore, electrophysiological measurement using a Nicolet Viking Quest device revealed significantly improved compound muscle action potential (CMAP) in shLenti­Mstn A­treated mice compared with the mock group (P<0.05) whereas nerve conduction velocity (NCV) showed no difference between groups. The shLenti­Mstn A treatment directly affected increased muscle regeneration, including mass and size, but not regeneration of peripheral nerve. Additionally, shLenti­Mstn A treatment significantly enhanced mobility, including locomotor coordination (P<0.01) and grip strength of the hindlimbs (P<0.01). Furthermore, MotoRater analysis using real­time recording with a high­speed camera revealed that shLenti­Mstn­treated mice exhibited an improved walking pattern in terms of step length, base support and duty factor compared with the mock group. It was hypothesized that treatment with shLenti­Mstn A may provide a novel therapeutic strategy for improving gait in patients with CMT1A.