Differential effects of myostatin deficiency on motor and sensory axons

Abstract

Introduction Deletion of myostatin in mice (MSTN−/−) alters structural properties of peripheral axons. However, properties like axon diameter and myelin thickness were analyzed in mixed nerves, so it is unclear if loss of myostatin affects motor, sensory or both types of axons. Methods Using the MSTN−/− mouse model, we analyzed the effects of increasing the number of muscle fibers on axon diameter, myelin thickness, and internode length in motor and sensory axons. Results Axon diameter and myelin thickness were increased in motor axons of MSTN−/− mice without affecting internode length or axon number. The number of sensory axons was increased without affecting their structural properties. Discussion These results suggest that motor and sensory axons establish structural properties by independent mechanisms. Moreover, in motor axons, instructive cues from the neuromuscular junction may play a role in co-regulating axon diameter and myelin thickness, while internode length is established independently.

Addressing the Need of a Translational Approach in Peripheral Neuropathy Research: Morphology Meets Function

“…The algorithm we proposed can be considered more comprehensive in respect to the others previously described. In the vast majority, only the motor system (most frequently one nerve) [ 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ] or only the sensory or mixed nerves [ 12 , 44 , 45 , 46 , 47 ] were tested. A few groups tested both the motor and sensory systems, but none of the tests were performed at the same time as EMG recordings [ 48 , 49 , 50 , 51 , 52 , 53 , 54 ].…”

Similar sequences but dissimilar biological functions of GDF11 and myostatin

“…Regarding the role of MSTN in the nervous system, examination of adult Mstn -null mice revealed that these mice exhibit increases in the number and size of axons and a delay in their age-related reduction 95 . Furthermore, MSTN-deficient mice were shown to display enhanced myelin thickness in motor axons and an increase in the number of sensory axons 96 . These mice were also shown to present a smaller brain size than wild-type mice at the age of 4 months, but the mechanism of brain size regulation by MSTN remains unclear 97 .…”