Resveratrol Ameliorates Muscular Pathology in the Dystrophic mdx Mouse, a Model for Duchenne Muscular Dystrophy

Abstract

Muscular dystrophies are inherited myogenic disorders accompanied by progressive skeletal muscle weakness and degeneration. We previously showed that resveratrol (3,5,4Ј-trihydroxy-trans-stilbene), an antioxidant and activator of the NAD ϩ -dependent protein deacetylase SIRT1, delays the progression of heart failure and prolongs the lifespan of ␦-sarcoglycan-deficient hamsters. Because a defect of dystroglycan complex causes muscular dystrophies, and ␦-sarcoglycan is a component of this complex, we hypothesized that resveratrol might be a new therapeutic tool for muscular dystrophies. Here, we examined resveratrol's effect in mdx mice, an animal model of Duchenne muscular dystrophy. mdx mice that received resveratrol in the diet for 32 weeks (4 g/kg diet) showed significantly less muscle mass loss and nonmuscle interstitial tissue in the biceps femoris compared with mdx mice fed a control diet. In the muscles of these mice, resveratrol significantly decreased oxidative damage shown by the immunostaining of nitrotyrosine and 8-hydroxy-2Ј-deoxyguanosine and suppressed the up-regulation of NADPH oxidase subunits Nox4, Duox1, and p47 phox . Resveratrol also reduced the number of ␣-smooth muscle actin (␣-SMA) ϩ myofibroblast cells and endomysial fibrosis in the biceps femoris, although the infiltration of CD45ϩ inflammatory cells and increase in transforming growth factor-␤1 (TGF-␤1) were still observed. In C2C12 myoblast cells, resveratrol pretreatment suppressed the TGF-␤1-induced increase in reactive oxygen species, fibronectin production, and expression of ␣-SMA, and SIRT1 knockdown blocked these inhibitory effects. SIRT1 small interfering RNA also increased the expression of Nox4, p47 phox , and ␣-SMA in C2C12 cells. Taken together, these findings indicate that SIRT1 activation may be a useful strategy for treating muscular dystrophies.

Effects of muscular dystrophy, exercise and blocking activin receptor IIB ligands on the unfolded protein response and oxidative stress

“…The effects of the altered phosphorylation of SIRT1 at Ser 46/47 on the activity of the protein are unclear. However, the interventions that increase the enzymatic activity of SIRT1 were suggested to be beneficial for muscular dystrophies [38,63]. On the other hand, even if the increased phosphorylation of SIRT1 at ser 46 caused by exercise alone or in combination with sAcvR2B-Fc would improve redox regulation, the outcome of the running com-bined with the sAcvR2B-Fc was a greater amount of protein carbonyls and increased level of oxidized glutathione that are indicators of elevated levels of oxidative stress and damage.…”

Resveratrol induces expression of the slow, oxidative phenotype in mdx mouse muscle together with enhanced activity of the SIRT1-PGC-1α axis

“…Following the 6-wk treatment period, mice were euthanized by CO 2 asphyxiation and cervical dislocation and the tibialis anterior (TA), extensor digitorum longus (EDL), soleus (SOL), and gastrocnemius (GAST) muscles were harvested and immediately frozen in liquid nitrogen or in melting isopentane cooled with liquid nitrogen for histological and immunofluorescence analyses. For the second RSV protocol, treated mdx mice were given a standard control diet, supplemented with RSV (ϳ 500 mg·kg Ϫ1 ·day Ϫ1 ) based on earlier work (29,46), and the duration was extended to 12 wk. This was considered a high dose and a long duration (HDLD).…”

“…Notably, this latter point is cause for debate (24,25,28,50,51,61). In recent years, treatment of dystrophic mdx mice with RSV was shown to result in beneficial adaptations (19,20,29,56). However, it is largely unknown whether chronic RSV administration promotes expression of the slow, oxidative phenotype in dystrophic skeletal muscle, as it does in muscles of wild-type animals, which could mitigate the dystrophic pathology (36,37,44,60).…”

“…Because of the promising results described above, we decided to perform an additional series of experiments where both the daily RSV dose and treatment duration were increased in an effort to determine if greater exposure to RSV yielded a more robust induction of therapeutic skeletal muscle plasticity. The dose was increased to ϳ500 mg·kg Ϫ1 ·day Ϫ1 , based in part, on recent literature (29,46), while the duration was extended to 12 wk (HDLD). Thus male mice of 6 -7 wk of age were once again divided into three groups, based on genetic background and diet: 1) WT-CTL, 2) MDX-CTL, and 3) MDX-RSV-HDLD.…”

Tmem2 regulates cell-matrix interactions that are essential for muscle fiber attachment

“…2F,H). This may represent a secondary consequence of laminin deficiency, since organized laminin has been shown to play an indirect role in facilitating fibronectin degradation at the MTJ (Jenkins et al, 2016); alternatively, increased fibronectin could be a secondary response to muscle fiber detachment, akin to the increased fibronectin fibrillogenesis seen in association with some myopathies (Hori et al, 2011;Rampoldi et al, 1986;Zacharias et al, 2011).…”