Obesity alters the expression profile of clock genes in peripheral blood mononuclear cells.
BACKGROUND
The aim of this study was to investigate the association between the variation in expression profile of clock genes and obesity using peripheral blood mononuclear (PMN) cells.


METHODS
The subjects comprised 10 obese patients and 10 healthy volunteers. Blood was collected at different time-points during the day and levels of blood sugar, IRI, adiponectin and leptin were determined. Peripheral blood mononuclear cells were sampled, and expression levels of brain and muscle Arnt-like protein-1 (BMAL1), Period (PER)1, PER2, Cryptochrome (CRY)1, CRY2, and REV-ERBα mRNA were quantified.


RESULTS
During the day, the expression levels of BMAL1, CRY1, CRY2 and PER2 genes in PMN cells of the obese group were all significantly higher compared to those in the non-obese group. In addition, expression of BMAL1, CRY1, CRY2 and PER2 genes in PMN cells increased between 12:00 and 21:00 in the obese group. In PMN cells of both groups, PER1 gene expression showed a bimodal pattern, with high expression at 9:00 and 18:00.


CONCLUSIONS
Differences were observed in the expression profile variation of clock genes between the obese and non-obese groups. This study reveals the differences in clock gene expression profiles between obese and non-obese subjects, with evidence for two distinct chronotypes, and suggests a contribution of these chronotypes to fat accumulation in humans.
Division of Nephrology, Hypertension and Endocrinology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan.
Kazunobu
K
Tahira
Takahiro
T
Ueno
Noboru
N
Fukuda
Takahiko
T
Aoyama
Akiko
A
Tsunemi
Siroh
S
Matsumoto
Chinami
C
Nagura
Taro
T
Matsumoto
Masayoshi
M
Soma
Shigeki
S
Shimba
Yoshiaki
Y
Matsumoto