Dataset Information

Transcription profiling of rat heart samples from animals with physiological or pathological cardiac hypertrophy

ABSTRACT: Dahl salt-sensitive (DS) rats were obtained from Harlan Sprague Dawley Laboratory at 5 weeks of age. At 6 weeks of age, physiologic cardiac hypertrophy was generated by a; vigorous daily exercise regimen for 6 weeks (e group). The exercise protocol is based on those described previously with modifications (Wisloff U et al., 2001; Jin H et al., 1994). Rats were exercised daily for 6 weeks on a rodent treadmill (Exer-6M; Columbus Instruments). The exercise program consisted of three weeks of progressively strenuous exercise regimens; followed by three weeks of maintenance period, during which the rats were exercised at 16 m/min at a 5o incline for 90 minutes/day. All rats completed the exercise protocol. Pathological cardiac hypertrophy was generated by feeding a 6% NaCl diet to DS rats at 6 weeks of age (h group) (Inoko M et al., 1994). Control rats (c group) were age matched and sedentary DS rats fed normal rat chow. Read more at http://cardiogenomics.med.harvard.edu/groups/proj1/pages/rat_home.html

Note that files GSM11886.txt and GSM12308.txt, and files GSM11887.txt and GSM12309.txt as downloaded from GEO contain identical data.

REANALYSIS of: E-GEOD-776

ORGANISM(S): Rattus norvegicus

DISEASE(S): pathologic cardiac hypertrophy,physiologic cardiac hypertrophy

PROVIDER: E-GEOD-776 | ExpressionAtlas | 2015-10-13

REPOSITORIES: ExpressionAtlas

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Project description:Purpose: Aerobic capacity is a strong predictor of cardiovascular mortality. To determine the relationship between inborn aerobic capacity and soleus gene expression we examined genome-wide gene expression in soleus muscle of rats artificially selected for high and low running capacity (HCR and LCR, respectively) over 16 generations. The artificial selection of LCR caused accumulation of risk factors of cardiovascular disease similar to the metabolic syndrome seen in man, whereas HCR had markedly better cardiac function. We also studied alterations in gene expression in response to exercise training in the two groups, since accumulating evidence indicates that exercise has profound beneficial effects on the metabolic syndrome. Methods:; Soleus gene expression of both sedentary and exercise trained HCR and LCR was characterized by microarray- and gene ontology analysis. Results: Although HCR and LCR had an inborn 347% difference in running capacity, only three genes were found differentially expressed in the soleus muscle between the two groups. Up-regulation of the mitochondrial enzyme leucyl-transferRNA synthetase (LARS2) was found in the sedentary LCR. Increased expression of LARS2 has been associated with a mitochondrial DNA mutation linked to maternally inherited diabetes and mitochondrial dysfunction. In line with our findings, a growing body of evidence suggests that LCR have compromised mitochondrial function. After exercise training, 58 genes were altered in the soleus muscle of HCR, in contrast to only one in the LCR group. This suggests that animals born with different levels of fitness respond different to the same type of exercise training. Adaptations to exercise in HCR seemed to be associated with increased lipid metabolism and fatty acid elongation in the mitochondria. Also, genes associated with the peroxisomes, seemed to be central in the adaptation to exercise. Conclusion: The results indicate that (i) LCR might have mitochondrial dysfunction, which may be a contributing factor of the low inborn aerobic capacity, (ii) animals born with different levels of fitness respond different to the same exercise program. Experiment Overall Design: There are 16 samples in this study.