The neuromuscular disorders are a heterogeneous group of genetic diseases, caused by mutations in genes coding sarcolemmal, sarcomeric, and citosolic muscle proteins. Deficiencies or loss of function of these proteins leads to variable degree of progressive loss of motor ability. Several animal models, manifesting phenotypes observed in neuromuscular diseases, have been identified in nature or generated in laboratory. These models generally present physiological alterations observed in human patients and can be used as important tools for genetic, clinic, and histopathological studies. The mdx mouse is the most widely used animal model for Duchenne muscular dystrophy (DMD). Although it is a good genetic and biochemical model, presenting total deficiency of the protein dystrophin in the muscle, this mouse is not useful for clinical trials because of its very mild phenotype. The canine golden retriever MD model represents a more clinically similar model of DMD due to its larger size and significant muscle weakness. Autosomal recessive limb-girdle MD forms models include the SJL/J mice, which develop a spontaneous myopathy resulting from a mutation in the Dysferlin gene, being a model for LGMD2B. For the human sarcoglycanopahties (SG), the BIO14.6 hamster is the spontaneous animal model for delta-SG deficiency, whereas some canine models with deficiency of SG proteins have also been identified. More recently, using the homologous recombination technique in embryonic stem cell, several mouse models have been developed with null mutations in each one of the four SG genes. All sarcoglycan-null animals display a progressive muscular dystrophy of variable severity and share the property of a significant secondary reduction in the expression of the other members of the sarcoglycan subcomplex and other components of the Dystrophin-glycoprotein complex. Mouse models for congenital MD include the dy/dy (dystrophia-muscularis) mouse and the allelic mutant dy(2J)/dy(2J) mouse, both presenting significant reduction of alpha2-laminin in the muscle and a severe phenotype. The myodystrophy mouse (Large(myd)) harbors a mutation in the glycosyltransferase Large, which leads to altered glycosylation of alpha-DG, and also a severe phenotype. Other informative models for muscle proteins include the knockout mouse for myostatin, which demonstrated that this protein is a negative regulator of muscle growth. Additionally, the stress syndrome in pigs, caused by mutations in the porcine RYR1 gene, helped to localize the gene causing malignant hypertermia and Central Core myopathy in humans. The study of animal models for genetic diseases, in spite of the existence of differences in some phenotypes, can provide important clues to the understanding of the pathogenesis of these disorders and are also very valuable for testing strategies for therapeutic approaches.

Bone marrow metastasis occurs in approximately 350,000 patients that annually die in the U.S. alone. In view of the importance of tumor cell migration into the bone marrow, we have here investigated effects of various concentrations of stromal cell-derived factor-1 (SDF-1), bradykinin- and ATP on bone marrow metastasis. We show for first time that bradykinin augmented chemotactic responsiveness of neuroblastoma cells to SDF-1 and ATP concentrations, encountered under physiological conditions. Bradykinin upregulated VEGF expression, increased metalloproteinase activity and induced adhesion of neuroblastoma cells. Bradykinin augmented SDF-1-induced intracellular Ca2+ mobilization as well as resensitization and expression of ATP-sensing P2X7 receptors. Bradykinin treatment resulted in higher gene expression levels of the truncated P2X7B receptor compared to those of the P2X7A full-length isoform. Bradykinin as pro-metastatic factor induced tumor proliferation that was significantly decreased by P2X7 receptor antagonists; however, the peptide did not enhance cell death nor P2X7A receptor-related pore activity, promoting neuroblastoma growth. Furthermore, immunodeficient nude/nude mice transplanted with bradykinin-pretreated neuroblastoma cells revealed significantly higher metastasis rates compared to animals injected with untreated cells. In contrast, animals receiving Brilliant Blue G, a P2X7 receptor antagonist, did not show any specific dissemination of neuroblastoma cells to the bone marrow and liver, and metastasis rates were drastically reduced. Our data suggests correlated actions of kinins and purines in neuroblastoma dissemination, providing novel avenues for clinic research in preventing metastasis.

Quantitative nuclear magnetic resonance imaging (MRI) has been considered a promising non-invasive tool for monitoring therapeutic essays in small size mouse models of muscular dystrophies. Here, we combined MRI (anatomical images and transverse relaxation time constant—T2—measurements) to texture analyses in the study of four mouse strains covering a wide range of dystrophic phenotypes. Two still unexplored mouse models of muscular dystrophies were analyzed: The severely affected Largemyd mouse and the recently generated and worst double mutant mdx/Largemyd mouse, as compared to the mildly affected mdx and normal mice. The results were compared to histopathological findings. MRI showed increased intermuscular fat and higher muscle T2 in the three dystrophic mouse models when compared to the wild-type mice (T2: mdx/Largemyd: 37.6±2.8 ms; mdx: 35.2±4.5 ms; Largemyd: 36.6±4.0 ms; wild-type: 29.1±1.8 ms, p<0.05), in addition to higher muscle T2 in the mdx/Largemyd mice when compared to mdx (p<0.05). The areas with increased muscle T2 in the MRI correlated spatially with the identified histopathological alterations such as necrosis, inflammation, degeneration and regeneration foci. Nevertheless, muscle T2 values were not correlated with the severity of the phenotype in the 3 dystrophic mouse strains, since the severely affected Largemyd showed similar values than both the mild mdx and worst mdx/Largemyd lineages. On the other hand, all studied mouse strains could be unambiguously identified with texture analysis, which reflected the observed differences in the distribution of signals in muscle MRI. Thus, combined T2 intensity maps and texture analysis is a powerful approach for the characterization and differentiation of dystrophic muscles with diverse genotypes and phenotypes. These new findings provide important noninvasive tools in the evaluation of the efficacy of new therapies, and most importantly, can be directly applied in human translational research.

SUMMARYAlthough muscular dystrophies are among the most common human genetic disorders, there are few treatment options available. Animal models have become increasingly important for testing new therapies prior to entering human clinical trials. The Dmdmdx mouse is the most widely used animal model for Duchenne muscular dystrophy (DMD), presenting the same molecular and protein defect as seen in humans with the disease. However, this mouse is not useful for clinical trials because of its very mild phenotype. The mouse model for congenital myodystrophy type 1D, Largemyd, harbors a mutation in the glycosyltransferase Large gene and displays a severe phenotype. To help elucidate the role of the proteins dystrophin and LARGE in the organization of the dystrophin-glycoprotein complex in muscle sarcolemma, we generated double-mutant mice for the dystrophin and LARGE proteins. The new Dmdmdx/Largemyd mouse model is viable and shows a severe phenotype that is associated with the lack of dystrophin in muscle. We tested the usefulness of our new mouse model for cell therapy by systemically injecting them with normal murine mesenchymal adipose stem cells (mASCs). We verified that the mASCs were hosted in the dystrophic muscle. The new mouse model has proven to be very useful for the study of several other therapies, because injected cells can be screened both through DNA and protein analysis. Study of its substantial muscle weakness will also be very informative in the evaluation of functional benefits of these therapies.

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Objectives-To review all patients with SCO2 mutations and to describe a Brazilian patient with cardioencephalomyopathy carrying compound heterozygous mutations in SCO2, one being the known pathogenic p.E140K mutation and the other a novel 12-base pair (bp) deletion at nucleotides 1519 through 1530 (c.1519_1530del).Design-Case report and literature review. Setting-University hospitalPatient-Infant girl presenting with an encephalomyopathy, inspiratory stridor, ventilator failure, progressive hypotonia, and weakness, leading to death.Main Outcome Measures-Clinical features, neuro-imaging findings, muscle biopsy with histochemical analysis, and genetic studies.Results-This infant girl was the first child of healthy, nonconsanguineous parents. She developed progressive muscular hypotonia and ventilatory failure. At the end of the first month of life, she developed cardiomegaly and signs of cardiac failure. Routine blood tests showed lactic acidosis and mild elevation of the creatine kinase level. Brain magnetic resonance imaging showed increased T2 and fluid-attenuated inversion recovery signals in the putamen bilaterally. Nerve conduction studies showed severe axonal sensorimotor neuropathy. Muscle biopsy revealed a neurogenic pattern with mitochondrial proliferation and total absence of cytochrome-c oxidase histochemical stain. Sequencing of SCO2 showed that the patient had compound heterozygote

Muscular dystrophies (MD) are a clinically and genetically heterogeneous group of Mendelian diseases. The underlying pathophysiology and phenotypic variability in each form are much more complex, suggesting the involvement of many other genes. Thus, here we studied the whole genome expression profile in muscles from three mice models for MD, at different time points: Dmd mdx (mutation in dystrophin gene), Large myd − / − (mutation in Large) and Dmd mdx /Large myd − / − (both mutations). The identification of altered biological functions can contribute to understand diseases and to find prognostic biomarkers and points for therapeutic intervention. We identified a substantial number of differentially expressed genes (DEGs) in each model, reflecting diseases' complexity. The main biological process affected in the three strains was immune system, accounting for the majority of enriched functional categories, followed by degeneration/regeneration and extracellular matrix remodeling processes. The most notable differences were in 21-day-old Dmd mdx , with a high proportion of DEGs related to its regenerative capacity. A higher number of positive embryonic myosin heavy chain (eMyHC) fibers confirmed this. The new Dmd mdx /Large myd − / − model did not show a highly different transcriptome from the parental lineages, with a profile closer to Large myd − / − , but not bearing the same regenerative potential as Dmd mdx . This is the first report about transcriptome profile of a mouse model for congenital MD and Dmd mdx /Large myd . By comparing the studied profiles, we conclude that alterations in biological functions due to the dystrophic process are very similar, and that the intense regeneration in Dmd mdx involves a large number of activated genes, not differentially expressed in the other two strains.

The bioactive peptide bradykinin obtained from cleavage of precursor kininogens activates the kinin-B2 receptor functioning in induction of inflammation and vasodilatation. In addition, bradykinin participates in kidney and cardiovascular development and neuronal and muscle differentiation. Here we show that kinin-B2 receptors are expressed throughout differentiation of murine C2C12 myoblasts into myotubes. An autocrine loop between receptor activation and bradykinin secretion is suggested, since bradykinin secretion is significantly reduced in the presence of the kinin-B2 receptor antagonist HOE-140 during differentiation. Expression of skeletal muscle markers and regenerative capacity were decreased after pharmacological inhibition or genetic ablation of the B2 receptor, while its antagonism increased the number of myoblasts in culture. In summary, the present work reveals to date no functions described for the B2 receptor in