Denervation-induced
muscle atrophy increases signaling through both protein degradation and synthesis pathways.
Renalase is a
flavin adenine dinucleotide-dependent
amine oxidase that inhibits apoptosis and
inflammation and promotes cell survival. This study aimed to elucidate the effect of
renalase on
denervation-induced
muscle atrophy. We used 7-week-old
renalase knock-out (KO) mice (a model of
denervation-induced
muscle atrophy) and wild-type (WT) mice (KO: n = 6, weight = 20-26 g; WT: n = 5, weight = 19-23 g). After their left legs were denervated, these mice were killed 1 week later. KO mice had lighter muscle weight than the WT mice. We observed an increase in molecular signaling through protein degradation pathway as well as oxidative stress in denervated muscles compared with that in
sham-operated muscles in both WT and KO mice. Additionally, we also observed the main effect of
renalase in WT and KO mice. Mitochondrial oxidative phosphorylation
protein content was lower in denervated muscles than in
sham-operated muscles in both WT and KO mice. However, a significant difference was noted in the reaction with Akt and
p70S6K (components of the
protein synthesis pathway) between WT and KO mice. In conclusion, mice with
renalase deficiency demonstrated an attenuation of
denervation-induced
muscle atrophy. This might be related to
catecholamines because signaling through the
protein synthesis pathway was increased following
denervation in
renalase KO mice compared with that in WT mice, despite showing no change in signaling through protein degradation pathways.