Changes in Expression of Skeletal Muscle Proteins between Obesity-Prone and Obesity-Resistant Rats Induced by a High-Fat Diet

Abstract

A primary goal in obesity research is to determine why some people become obese (obesity-prone, OP) and others do not (obesity-resistant, OR) when exposed to high-calorie diets. The metabolic changes that cause reduced adiposity and resistance to obesity development have yet to be determined. We thus performed proteomic analysis on muscular proteins from OP and OR rats in order to determine whether other novel molecules are involved in this response. To this end, rats were fed a low- or high-fat diet for 8 weeks and were then classified into OP and OR rats by body weight gain. OP rats gained about 25% more body weight than OR rats, even though food intake did not differ significantly between the two groups. Proteomic analysis using 2-DE demonstrated differential expression of 26 spots from a total of 658 matched spots, of which 23 spots were identified as skeletal muscle proteins altered between OP and OR rats by peptide mass fingerprinting. Muscle proteome data enabled us to draw the conclusion that enhanced regulation of proteins involved in lipid metabolism and muscle contraction, as well as increased expression of marker proteins for oxidative muscle type (type I), contributed to obesity-resistance; however, antioxidative proteins did not.

A nontargeted study of muscle proteome in severely obese women with androgen excess compared with severely obese men and nonhyperandrogenic women

“…Since the proteome -the set of proteins present in a tissue -is the result of gene expression and epigenetic influences, the study of protein abundance in muscle may provide new insights into the molecular processes that lead to metabolic dysfunction in situations where the concentrations of circulating androgens are altered, an issue that has not been addressed in previous proteomic studies of muscle in insulin resistance-related disorders (8,9,10).…”

Alterations in Pancreatic Protein Expression in STZ-Induced Diabetic Rats and Genetically Diabetic Mice in Response to Treatment with Hypoglycemic Dipeptide Cyclo (His-Pro)

“…Proteomics is a powerful tool used to describe changes in protein expression and modification, and moreover, it holds the promise of providing major contributions to diabetes research as well as other metabolic syndromes due to its potential to dissect complex human disorders [14][15][16][17][18][19][20]. A series of proteomic studies have been performed on both whole pancreatic tissues as well as isolated islets of Langerhans from mice [21,22] and rats [14][15][16][17][18][19][20][21][22][23][24][25][26][27].…”

Gender-Dimorphic Regulation of Skeletal Muscle Proteins in Streptozotocin-Induced Diabetic Rats

“…First, proteins were resolved on a broad-range IEF strip (pH 3-10, non-linear gradient) in the first dimension and on a 12% SDS-PAGE gel in the second dimension, as outlined by our previous studies [24,27]. However, improved resolution could be obtained when the first dimension separation was carried out on a pH 4-7 rather than pH 3-10 IEF strip.…”

“…2-DE was performed using protein extracts from the muscles of six rats per group, as described previously [24,25]. For minimization of gel-to-gel variation, this experiment pooled muscle protein extracts from six rats, and three sheets of 2-DE gels per group were prepared.…”

“…Gel strips were then subjected to 20×20 cm 2 10% SDS-polyacrylamide gel electrophoresis, after which fractionation was performed on the Laemmli SDS-discontinuous system at a constant voltage of 15 mA per gel. The separated gels were visualized by silver staining as described previously [24,25]. …”