Effects of Fasting and Re-Feeding on the Expression of Dec1, Per1, and Other Clock-Related Genes

Abstract

To elucidate the food-entrainable oscillatory mechanism of peripheral clock systems, we examined the effect of fasting on circadian expression of clock genes including Dec1 and Dec2 in mice. Withholding of food for 2 days had these effects: the expression level of Dec1 mRNA decreased in all tissues examined, although Per1 mRNA level markedly increased; Per2 expression was reduced in the liver and heart only 42-46 h after the start of fasting; and expression profiles of Dec2 and Bmal1 were altered only in the heart and in the liver, respectively, whereas Rev-erbalpha mRNA levels did not change significantly. Re-feeding after 36-h starvation erased, at least in part, the effect of fasting on Dec1, Dec2, Per1, Per2, and Bmal1 within several hours, and restriction feeding shifted the phase of expression profiles of all examined clock genes including Dec1 and Dec2. These findings indicate that short-term fasting and re-feeding modulate the circadian rhythms of clock genes to different extents in peripheral tissues, and suggest that the expression of Dec1, Per1, and some other clock genes was closely linked with the metabolic activity of these tissues.

Significant dissociation of expression patterns of the basic helix–loop–helix transcription factors Dec1 and Dec2 in rat kidney

“…and rhythmic expression of Dec2 in the kidney of rats under a normal LD cycle. This differs not only from the circadian expression of Dec1 and Dec2 in the heart (present study) and in the SCN (Butler et al, 2004;Honma et al, 2002) and other peripheral tissues (Kawamoto et al, 2006;Kawamoto et al, 2004;Wu et al, 2008a;Wu et al, 2008b) of rats and mice but also from observations in mouse kidney (Hamaguchi et al, 2004;Noshiro et al, 2005), which suggests tissue-and species-specific mechanisms underlying the circadian expression of these two clock genes. This unusual phenomenon may be the cause of overlapping functions of Dec1 and Dec2 in maintaining and entraining circadian rhythms.…”

“…Moreover, expression of Dec1 and Dec2 shows circadian rhythm in most organs, including the suprachiasmatic nucleus (SCN) (Honma et al, 2002;Kawamoto et al, 2006;Kawamoto et al, 2004;Noshiro et al, 2004). In the mammalian clock system, CLOCK and BMAL1 form heterodimers that bind to E-boxes in the promoter region of various target genes, including negative regulators (e.g.…”

“…Moreover, Dec1 and Dec2 gene expression was differently altered in the pineal gland of rats by photoperiod (Engel et al, 2005) and in some peripheral tissues of mice by fasting and re-feeding Kawamoto et al, 2006). Therefore, in the present study, we investigated whether Dec1 and Dec2 are actually expressed in a similar manner in rat kidney and then examined the effects of multiple external and internal cues on the expression of these two genes.…”

Hepatic Differentiated Embryo-Chondrocyte-expressed Gene 1 (Dec1) Inhibits Sterol Regulatory Element-binding Protein-1c (Srebp-1c) Expression and Alleviates Fatty Liver Phenotype

“…hepatic Dec1 expression is regulated by nutritional status; fasting decreased its expression, and refeeding after fasting restored the decreased Dec1 mRNA (27). Consistent with these data, insulin rapidly induces the expression of the Dec1 gene in primary hepatocytes (28).…”

A Time to Fast, a Time to Feast: The Crosstalk between Metabolism and the Circadian Clock

“…Moreover, HFF affects clock gene rhythms in the liver as well as the circadian pattern of leptin, insulin and glucocorticoid levels in the blood (Kohsaka=et alK, 2007). Interestingly, not only feeding but also the complete withdrawal of food during fasting changes clock gene expression in peripheral tissues (Kawamoto=et alK, 2006). Obesity-inducing genetic mutations also lead to severe impairments of circadian rhythmicity.…”