Histamine induces the expression of uncoupling protein 2 (UCP2) and acid-binding protein (aP2) in white adipocytes.
BACKGROUND
The aim of the present study was to investigate whether histamine induces up-regulated expression of uncoupling protein 2 (UCP2) and fat acid-binding protein (aP2) in white adipocytes (differentiated 3T3-L1 cells).


METHODS
Differentiation of 3T3-L1 preadipocytes to adipocytes was induced by the addition of 5 microg/mL insulin, 1 micromol/L dexamethasone, 10 mmol/L 1-isobutyl-3-methylxanthine, 1% dimethylsulfoxide, and 10% fetal bovine serum in Dulbecco's modification of Eagle's medium. Total RNA from differentiated 3T3-L1 cells was extracted and semi-quantitative RT-PCR was performed to determine the levels of UCP2 and aP2 mRNA. The expression level of UCP2 protein was determined by Western blot analysis.


RESULTS
Histamine at a concentration of 30 micromol/L significantly increased the expression of UCP2 mRNA and UCP2 protein, and expression levels reached a peak value. There were significant differences in the expression levels of UCP2 mRNA and UCP2 protein in adipocytes treated with 30 micromol/L histamine at various time points within 48 h, and their levels reached a peak value after 6 h of incubation. In addition, histamine increased the expression level of aP2 mRNA in adipocytes. Expression of aP2 mRNA in adipocytes reached the highest value at a concentration of 20 micromol/L histamine after 6-h incubation. Finally, we found that diphenhydramine (a H1 receptor antagonist) significantly decreased expression levels of UCP2 mRNA and protein, as well as aP2 mRNA. There were significant differences in expression levels of UCP2 and aP2 mRNA in adipocytes treated at concentrations of 20 micromol/L histamine and diphenhydramine, respectively.


CONCLUSIONS
These data reveal that histamine up-regulated the expression of UCP2 and aP2 in vitro in white adipocytes.
Zeng
Hui
H
Pharmacogenetics Research Institute, Institute of Clinical Pharmacology, Central South University Xiang-Ya School of Medicine, Hunan, P.R. China.
Tang
Zhong-Yang
ZY
Zhang
Feng
F
Li
Hui-Hua
HH
Liu
Li-Hui
LH
Zhou
Hong-Hao
HH
Hu
Min-Yu
MY
Liu
Zhao-Qian
ZQ
D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology; D052438:Adipocytes, White / Q000378:metabolism*; D000818:Animals; D002454:Cell Differentiation; D004155:Diphenhydramine / Q000494:pharmacology; D050556:Fatty Acid-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D006632:Histamine / Q000378:metabolism*; D006801:Humans; D007473:Ion Channels / Q000235:genetics* / Q000502:physiology*; D051379:Mice; D024101:Mitochondrial Proteins / Q000235:genetics* / Q000502:physiology*; D008954:Models, Biological; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors; D000071246:Uncoupling Protein 2; D015854:Up-Regulation
C493411:Fabp4 protein, mouse; D050556:Fatty Acid-Binding Proteins; D007473:Ion Channels; D024101:Mitochondrial Proteins; D012333:RNA, Messenger; C000604389:UCP2 protein, human; C000604390:Ucp2 protein, mouse; D000071246:Uncoupling Protein 2; D006632:Histamine; D004155:Diphenhydramine