Non-targeted Metabolomics Analysis of Golden Retriever Muscular Dystrophy-Affected Muscles Reveals Alterations in Arginine and Proline Metabolism, and Elevations in Glutamic and Oleic Acid In Vivo
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ABSTRACT: Like Duchenne muscular dystrophy (DMD), the Golden Retriever Muscular Dystrophy (GRMD) dog model of DMD exhibits is characterized by muscle necrosis, progressive paralysis, and pseudohypertrophy in specific skeletal muscles. This severe GRMD phenotype included atrophy of the biceps femoris (BF) and compared to unaffected normal dogs, while the long digital extensor (LDE) of the pelvic limb, serving as a hip flex and stifle extensor, is unaffected. A recent microarray analysis of GRMD identified alterations in genes associated with lipid metabolism and energy production. We, therefore, undertook a non-targeted metabolomics analysis of the GRMD BF (affected) and LDE (unaffected) using GC-MS to identify underlying metabolic defects specific for affected GRMD skeletal muscle. Of the 134 metabolites identified in BF, eight were significantly altered in GRMD BF compared to control BF (Glutamic Acid (2.48 fold vs. controls); Oleic Acid (1.76 fold vs. controls); Proline (1.73 fold vs. controls); Myoinositol-2- Phosphate (0.44 fold vs. controls); Fumaric Acid (0.40 fold vs. controls); Carnosine (0.40 fold vs. controls); Lactamide (0.33 fold vs. controls); and Stearamide (0.23 fold vs. controls). Pathway analysis of the T-test significant metabolites identified BF muscle metabolites significantly enriched for Arginine and proline metabolism (p=5.8E-4, FDR=0.04) and Alanine, aspartate, and glutamate metabolism (p=1.3E-3, FDR=0.05). The GRMD LDE previously reported to be unaffected, in contrast, had only one significantly altered metabolite (3-Phosphoglyceric Acid (0.35 Fold vs. controls)).The identification of elevated BF Oleic acid (a long-chain fatty acid) is consistent with recent microarray studies identifying altered lipid metabolism genes, while alterations in Arginine and Proline metabolism are consistent with recent studies identifying elevated L-arginine in DMD patient sera as a biomarker of disease (alterations in DMD or GRMD muscle itself have not previously been reported).Together, these studies demonstrate muscle-specific alterations in GRMD-affected muscle, which illustrate previously unidentified metabolic changes.
ORGANISM(S): Canis Lupus Familiaris Dog
TISSUE(S): Muscle
DISEASE(S): Muscular Dystrophy
SUBMITTER: Monte Willis
PROVIDER: ST000623 | MetabolomicsWorkbench | Thu Apr 27 00:00:00 BST 2017
REPOSITORIES: MetabolomicsWorkbench
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