|
KMID : 0811720120160060393
|
|
Korean Journal of Physiology & Pharmacology
2012 Volume.16 No. 6 p.393 ~ p.398
|
|
|
Dexamethasone Induces FcgRIIb Expression in RBL-2H3 Cells
|
|
Prashanta Silwal
Lee Mi-Nam
Lee Choong-Jae
Hong Jang-Hee
Namgung Uk
Lee Zee-Won
Kim Jin-hyun
Lim Kyu
Kweon Gi-Ryang
Park Jong-Il
Park Seung-Kiel
|
|
|
Abstract
|
|
|
|
Mast cells are involved in allergic responses, protection against pathogens and autoimmune diseases. Dexamethasone (Dex) and other glucocorticoids suppress Fc?RI-mediated release of inflammatory mediators from mast cells. The inhibition mechanisms were mainly investigated on the downstream signaling of Fc receptor activations. Here, we addressed the effects of Dex on Fc receptor expressions in rat mast cell line RBL-2H3. We measured mRNA levels of Fc receptors by real-time PCR. As expected, Dex decreased the mRNA levels of activating Fc receptor for IgE (Fc?R) I and increased the mRNA levels of the inhibitory Fc receptor for IgG Fc?RIIb. Interestingly, Dex stimulated transcriptions of other activating receptors such as Fc receptors for IgG (Fc?R) I and Fc?RIII. To investigate the mechanisms underlying transcriptional regulation, we employed a transcription inhibitor actinomycin D and a translation inhibitor cycloheximide. The inhibition of protein synthesis without Dex treatment enhanced Fc?RI and Fc?RIII mRNA levels potently, while Fc?RI and Fc?RIIb were minimally affected. Next, we examined expressions of the Fc receptors on cell surfaces by the flow cytometric method. Only Fc?RIIb protein expression was significantly enhanced by Dex treatment, while Fc?RI, Fc?RIII and Fc?RI expression levels were marginally changed. Our data showed, for the first time, that Dex regulates Fc receptor expressions resulting in augmentation of the inhibitory receptor Fc?RIIb.
|
|
|
KEYWORD
|
|
|
Degranulation, Fc receptor, Glucocorticoid, Mast cells, Transcription
|
|
|
FullTexts / Linksout information
|
|
|
|
|
Listed journal information
|
|
  
|
|