Food entrainment of circadian gene expression altered in PPARalpha-/- brown fat and heart.
The circadian clock is subject to food entrainment. Since PPARalpha exhibits a circadian expression profile, we hypothesized that PPARalpha deficiency would alter the food entrainable response of adipose, cardiac, and liver tissues. Wild-type and PPARalpha null mice were compared under ad libitum or restricted food access for the expression of circadian transcription factor-encoding mRNAs. Temporally restricted food access caused between a mean 5.8-11.5 h phase shift in the expression profiles of the circadian genes Bmal1, Per3, and Rev-erbalpha in all tissues of control mice. In contrast, these same conditions phase shifted the circadian genes in tissues of PPARalpha null mice between a mean of 10.8-14.2 h with amplitude attenuation. The food entrained phase shifts in the brown adipose and cardiac tissue circadian transcription factors of the PPARalpha null mice were prolonged significantly relative to wild-type controls. Likewise, PPARalpha responsive genes in the livers of PPARalpha null mice exhibited a significantly prolonged phase shift relative to control mice. These findings confirm and extend recent observations in the literature.
Goh
Brian C
BC
Stem Cell Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA.
Wu
Xiying
X
Evans
Ann E
AE
Johnson
Meagan L
ML
Hill
Molly R
MR
Gimble
Jeffrey M
JM
D002001:Adipose Tissue, Brown / Q000378:metabolism*; D000818:Animals; D002940:Circadian Rhythm; D005502:Food; D020869:Gene Expression Profiling; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009206:Myocardium / Q000378:metabolism*