Regulation of haptoglobin expression in a human keratinocyte cell line HaCaT by inflammatory cytokines and dexamethasone.
BACKGROUND
Haptoglobin (Hp) is one of the acute-phase proteins. Recent studies have demonstrated that Hp exerts immunoregulatory and anti-inflammatory actions and may be one of the inhibitory factors of immune reactions in the skin. In this study we investigated the regulation of Hp expression in a human keratinocyte cell line HaCaT by various cytokines and glucocorticoid.


METHODS
HaCaT cells were cultured with IL-6 (50 ng/ml), TNF-alpha (20 ng/ml), IFN-gamma (20 ng/ml) or IL-4 (20 ng/ml) with or without 1 micromol/L dexamethasone in 6-well plates for 12, 24 and 48 hours. Both the cells and the supernatants were collected to detect the changes of Hp expression by reverse-transcription PCR, ELISA and immunohistochemistry.


RESULTS
The results showed that Hp expression were elevated at both the mRNA and protein level by the combination of IL-6, TNF-alpha or IL-4 with dexamethasone, whereas the three cytokines alone did not upregulate the Hp expression. IFN-gamma showed no effect on the Hp expression in HaCaT cells.


CONCLUSIONS
These findings suggest that different inflammatory cytokines as well as glucocorticoid may be involved in the regulation of Hp expression in keratinocytes, and this may be one of the negative feedback mechanisms in inflammatory skin diseases.
Xia
Li-xin
LX
Department of Dermatology, No 1 Hospital of China Medical University, Shenyang, Liaoning 110001, China.
Xiao
Ting
T
Chen
Hong-duo
HD
Li
Ping
P
Wang
Ya-kun
YK
Wang
He
H
D002460:Cell Line; D003907:Dexamethasone / Q000494:pharmacology*; D005938:Glucocorticoids / Q000494:pharmacology*; D006242:Haptoglobins / Q000032:analysis*; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D015847:Interleukin-4 / Q000494:pharmacology*; D015850:Interleukin-6 / Q000494:pharmacology*; D015603:Keratinocytes / Q000737:chemistry* / Q000187:drug effects*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D005938:Glucocorticoids; D006242:Haptoglobins; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D015847:Interleukin-4; D003907:Dexamethasone; D007371:Interferon-gamma