Upregulation of Toll-like receptor (TLR) expression and release of cytokines from P815 mast cells by GM-CSF.
BACKGROUND
Recently, mast cells have been recognized to express several Toll-like receptors (TLRs) on their membrane surfaces, and granulocyte-macrophage colony-stimulating factor (GM-CSF) was reported to be able to alter expression of TLRs and cytokine production in neutrophils. However, whether GM-CSF modulates the expression of TLR and cytokine production in mast cells is not clear.


RESULTS
Using flow cytometry and real time PCR techniques, we found that GM-CSF upregulated expression of TLR3 and TLR7 in P815 cells in a concentration dependent manner. GM-CSF also provoked approximately up to 2.4 and 2.3 fold increase in IL-13 and IL-6 release from P815 cells, respectively following 16 h incubation. GM-CSF induced IL-13 secretion, TLR3 and TLR7 expression appeared to be through activation of mitogen-activated protein kinase (MAPK) and phosphotidylinositol 3-kinase (PI3K)/Akt signaling pathways, whereas GM-CSF elicited IL-6 release seemed via Akt signaling pathway. At 10 ng/ml, GM-CSF significantly enhanced R-848-induced IL-6 release from P815 cells.


CONCLUSIONS
The ability of GM-CSF in modulation of expression of TLR3 and TLR7 in P815 mast cells and in stimulation of IL-13 and IL-6 release from P815 mast cells in vitro suggests that GM-CSF might play an important role in enhancing the innate immune responses of mast cell to viral infection.
Yang
Haiwei
H
Clinical Research Center, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, PR China. yanghaiwei2002@yahoo.com.cn
Wei
Jifu
J
Zhang
Huiyun
H
Lin
Liyan
L
Zhang
Wei
W
He
Shaoheng
S
D000818:Animals; D045744:Cell Line, Tumor; D016207:Cytokines / Q000276:immunology*; D015870:Gene Expression; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000276:immunology*; D018793:Interleukin-13 / Q000276:immunology; D015850:Interleukin-6 / Q000276:immunology; D008407:Mast Cells / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000276:immunology; D051379:Mice; D051196:Toll-Like Receptor 3 / Q000235:genetics* / Q000276:immunology; D051199:Toll-Like Receptor 7 / Q000235:genetics* / Q000276:immunology; D015854:Up-Regulation
D016207:Cytokines; D018793:Interleukin-13; D015850:Interleukin-6; D008562:Membrane Glycoproteins; C495344:TLR3 protein, human; C477038:Tlr7 protein, mouse; D051196:Toll-Like Receptor 3; D051199:Toll-Like Receptor 7; D016178:Granulocyte-Macrophage Colony-Stimulating Factor