Changes in gene expression in skeletal muscle in response to fat overfeeding in lean men.
OBJECTIVE
The adaptive mechanisms in response to excess energy supply are still poorly known in humans. Our aims were to define metabolic responses and changes in gene expression in skeletal muscle of healthy volunteers during fat overfeeding.


METHODS
Eight lean young healthy men were given a diet rich in saturated fat with an excess of approximately 550 kcal/d for 4 weeks. Using oligonucleotide microarrays, gene expression changes in skeletal muscle were analyzed at Day 0, Day 14, and Day 28.


RESULTS
Fat overfeeding led to an increase in body weight (1.0 +/- 0.3 kg) and waist circumference (2.2 +/- 0.5 cm, p = 0.005) and a significant decrease in fasting non-esterified fatty acid plasma levels (-29 +/- 5%, p = 0.028). Respiratory quotient was significantly increased (0.84 +/- 0.01 to 0.88 +/- 0.02, p = 0.034) and lipid oxidation rate tended to decrease. The expression of 55 genes was modified in skeletal muscle. The main pathways indicated a coordinated stimulation of triacylglycerol synthesis, inhibition of lipolysis, reduction of fatty acid oxidation, and development of adipocytes. Promoter analysis of the regulated genes suggests that sterol regulatory element binding proteins might be important players of the short-term adaptation to fat overfeeding in human skeletal muscle.


CONCLUSIONS
This combined metabolic and genomic investigation shows that fat overfeeding for 28 days promotes the storage of the excess energy in lean men and demonstrates the usefulness of a transcriptomic approach to a better understanding of the metabolic adaptation to changes in nutritional behavior in human.
Meugnier
Emmanuelle
E
Centre de Documentation en Ethique de l'Inserm (INSERM), U870, Lyon, France.
Bossu
Cécile
C
Oliel
Myriam
M
Jeanne
Sakina
S
Michaut
Angélique
A
Sothier
Monique
M
Brozek
John
J
Rome
Sophie
S
Laville
Martine
M
Vidal
Hubert
H
D052242:Adiponectin / Q000097:blood; D000328:Adult; D001706:Biopsy; D001823:Body Composition / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D004041:Dietary Fats / Q000494:pharmacology*; D000074026:Fatty Acid Binding Protein 3; D050556:Fatty Acid-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D006963:Hyperphagia / Q000378:metabolism*; D008066:Lipolysis / Q000187:drug effects; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D012333:RNA, Messenger / Q000378:metabolism; D051779:Sterol Regulatory Element Binding Proteins / Q000235:genetics / Q000378:metabolism; D013851:Thinness / Q000378:metabolism*; D014280:Triglycerides / Q000378:metabolism
D052242:Adiponectin; D004041:Dietary Fats; C493408:FABP3 protein, human; C493410:FABP4 protein, human; D000074026:Fatty Acid Binding Protein 3; D050556:Fatty Acid-Binding Proteins; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D012333:RNA, Messenger; D051779:Sterol Regulatory Element Binding Proteins; D014280:Triglycerides; D017346:Protein Serine-Threonine Kinases