Nutrition modulates Fto and Irx3 gene transcript levels, but does not alter their DNA methylation profiles in rat white adipose tissues.
The fat mass and obesity associated (Fto) and iroquois homeobox 3 (Irx3) genes have been recognised as important obesity-related genes. Studies on the expression of these genes in the fat tissue of human and mouse have produced inconsistent results, while similar data on rat are limited. Environmental factors such as diet, should be considered as potential modulators of gene transcript levels through epigenetic mechanisms including DNA methylation. The aim of this study was to evaluate transcription levels and DNA methylation profiles of rat Fto and Irx3 genes in two white adipose tissue depots in response to high-fat and high-protein diets. The relative transcript levels of Fto and Irx3 were shown to be tissue-specific with higher levels detected in subcutaneous fat tissue than in abdominal fat tissue. Moreover, negative correlations between the transcripts of both genes were observed for subcutaneous fat tissue. The identified interactions (e.g. diet×duration of diet regimen) indicated that the diet had an impact on the transcript level; however, this effect was dependent on the duration of the diet regimen. The high-fat diet led to upregulation of Fto and Irx3 linearly with time across the two tissues. DNA methylation of the regulatory regions of the studied genes was very low and not related with the tissue, diet, or duration of diet regimen. Our study revealed that diet was an important factor modulating transcription of Fto and Irx3, but its effect is time-dependent. In contrast, the DNA methylation profiles of Fto and Irx3 were not altered by nutrition, which may indicate that the feeding type, when applied postnatally, did not affect DNA methylation of these genes.
Department of Genetics and Animal Breeding, Poznan University of Life Sciences, Poland. Electronic address: jnowacka@up.poznan.pl.
Joanna
J
Nowacka-Woszuk
Department of Animal Physiology and Biochemistry, Poznan University of Life Sciences, Poland. Electronic address: ewaprusz@up.poznan.pl.
Ewa
E
Pruszynska-Oszmalek
Department of Genetics and Animal Breeding, Poznan University of Life Sciences, Poland. Electronic address: maciej@up.poznan.pl.
Maciej
M
Szydlowski
Department of Genetics and Animal Breeding, Poznan University of Life Sciences, Poland. Electronic address: izabel@up.poznan.pl.
Izabela
I
Szczerbal
D050153:Abdominal Fat / Q000378:metabolism; D052436:Adipose Tissue, White / Q000378:metabolism*; D000071516:Alpha-Ketoglutarate-Dependent Dioxygenase FTO / Q000235:genetics*; D000818:Animals; D001835:Body Weight; D019175:DNA Methylation; D059305:Diet, High-Fat; D004044:Dietary Proteins / Q000008:administration & dosage*; D018398:Homeodomain Proteins / Q000235:genetics*; D008297:Male; D009765:Obesity / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D050151:Subcutaneous Fat / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics*
D004044:Dietary Proteins; D018398:Homeodomain Proteins; C000615646:Irx3 protein, rat; D014157:Transcription Factors; D000071516:Alpha-Ketoglutarate-Dependent Dioxygenase FTO; C529321:FTO protein, rat
High-fat diet; High-protein diet; Methylation profile; Rat; Transcript level; White adipose tissue