Congenital Muscular Dystrophy type 1D (MDC1D) is characterized by a hypoglycosylation of α-dystroglycan protein (α-DG), and this may be strongly implicated in increased skeletal muscle tissue degeneration and abnormal brain development, leading to cognitive impairment. However, the pathophysiology of brain involvement is still unclear. Low-intensity exercise training (LIET) is known to contribute to decreased muscle degeneration in animal models of other forms of progressive muscular dystrophies. The objective of this study was to analyze the effects of LIET on cognitive involvement and oxidative stress in brain tissue and gastrocnemius muscle. Male homozygous (Largemyd-/-), heterozygous (Largemyd+/-), and wild-type mice were used. To complete 28 days of life, they were subjected to a low-intensity exercise training (LIET) for 8 weeks. After the last day of training, 24 h were expected when the animals were submitted to inhibitory avoidance and open-field test. The striatum, prefrontal cortex, hippocampus, cortex, and gastrocnemius were collected for evaluation of protein carbonylation, lipid peroxidation, and catalase and superoxide dismutase activity. LIET was observed to reverse the alteration in aversive and habituation memory. Increased protein carbonylation in the striatum, prefrontal cortex, and hippocampus and lipid peroxidation in the prefrontal cortex and hippocampus were also reversed by LIET. In the evaluation of the antioxidant activity, LIET increased catalase activity in the hippocampus and cortex. In the gastrocnemius, LIET decreased the protein carbonylation and lipid peroxidation and increased catalase and superoxide dismutase activity. In conclusion, it can be inferred that LIET for 8 weeks was able to reverse the cognitive damage and oxidative stress in brain tissue and gastrocnemius muscle in MDC1D animals.

Congenital Muscular Dystrophy type 1D (CMD1D) is characterized by an abnormal glycosylation of α-DG (α-dystroglycan) and is associated to the central nervous system (CNS) abnormalities such as cognitive impairment. The purpose of the research was to evaluate the blood-brain barrier permeability (BBB) permeability and matrix metalloproteinases (MMP) -2 and -9 in adult Largemyd-/- mice in order to understand the physiopathology of brain involvement during the CMD1D process. To this aim, we used adult homozygous Largemyd-/- (mutation in Large), heterozygous Largemyd+/- as well as wild-type (C57BL/6) mice. The animals were submitted to the evaluation of BBB permeability and MMP-2 and MMP-9 in striatum, hippocampus and cerebral cortex. There was an increase in BBB permeability in the hippocampus and striatum associated with an increase in the protein levels of MMP-2 in the cerebral cortex and striatum and MMP-9 in the hippocampus in adult Largemyd-/- mice. Our results suggest that the pathophysiologic processes can be associated to the action of MMPs and BBB disruption and that the BBB breakdown is relevant to the perpetuation of brain inflammation and can be related to brain dysfunction observed in CMD1D patients.

α-Dystroglycanopathy (α-DGP) is a group of muscular dystrophy characterized by abnormal glycosylation of α-dystroglycan (α-DG), including Fukuyama congenital muscular dystrophy (FCMD), muscle-eye-brain disease, Walker-Warburg syndrome, and congenital muscular dystrophy type 1D (MDC1D), etc. LARGE, the causative gene for MDC1D, encodes a glycosyltransferase to form [-3Xyl-α1,3GlcAβ1-] polymer in the terminal end of the post-phosphoryl moiety, which is essential for α-DG function. It has been proposed that LARGE possesses the great potential to rescue glycosylation defects in α-DGPs regardless of causative genes. However, the in vivo therapeutic benefit of using LARGE activity is controversial. To explore the conditions needed for successful LARGE gene therapy, here we used Large-deficient and fukutin-deficient mouse models for MDC1D and FCMD, respectively. Myofibre-selective LARGE expression via systemic adeno-associated viral gene transfer ameliorated dystrophic pathology of Large-deficient mice even when intervention occurred after disease manifestation. However, the same strategy failed to ameliorate the dystrophic phenotype of fukutin-conditional knockout mice. Furthermore, forced expression of Large in fukutin-deficient embryonic stem cells also failed to recover α-DG glycosylation, however coexpression with fukutin strongly enhanced α-DG glycosylation. Together, our data demonstrated that fukutin is required for LARGE-dependent rescue of α-DG glycosylation, and thus suggesting new directions for LARGE-utilizing therapy targeted to myofibres.