Short-term and long-term cytokine release by mouse bone marrow mast cells and the differentiated KU-812 cell line are inhibited by brefeldin A.
Mast cells and basophils produce a wide range of cytokines, including large amounts of both IL-6 and granulocyte-macrophage CSF (GM-CSF). However, the route by which cytokines are secreted is poorly understood. In the current study, we used two inhibitors of vesicular transport, brefeldin A and monensin, to examine the routes of secretion of IL-6 and GM-CSF in the differentiated KU812 human cell line and cultured mouse bone marrow mast cells (mBMMC). Studies of cytokine production over 6 to 24 h demonstrated that IL-6 and GM-CSF release from both cell types were inhibited by brefeldin A (BFA) following activation with calcium ionophore, A23187. Monensin had similar inhibitory effects to that of BFA on the initial and ongoing IL-6 release from KU812 cells. In contrast, the amount of each cytokine remaining within the cells was significantly enhanced. Similar results were obtained following IgE-mediated activation of mBMMC. BFA significantly inhibited both the constitutive secretion of IL-6 and the immediate ionophore-induced increase in IL-6 release from KU812 cells at 20 min postactivation. However, treatment with these agents did not alter the release of histamine and beta-hexaminidase from either mBMMC or KU812 cells. These studies suggest that both the initial 20-min release of IL-6 and secretion of IL-6 and GM-CSF over up to 24 h by mBMMC and differentiated KU-812 cells occur predominately through a vesicular transport-dependent mechanism, and that little, if any, IL-6 and GM-CSF is released through degranulation.
Zhu
F G
FG
Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada.
Gomi
K
K
Marshall
J S
JS
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001491:Basophils / Q000187:drug effects / Q000378:metabolism; D001854:Bone Marrow Cells / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D020126:Brefeldin A; D015550:Cell Degranulation / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D003517:Cyclopentanes / Q000494:pharmacology*; D016207:Cytokines / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D003594:Cytoplasmic Granules / Q000187:drug effects / Q000378:metabolism; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D006131:Growth Inhibitors / Q000494:pharmacology; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D018942:Macrolides; D008297:Male; D008407:Mast Cells / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D051379:Mice; D008810:Mice, Inbred C57BL; D008985:Monensin / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D013997:Time Factors; D000093242:Interleukin-6 Inhibitors
D000900:Anti-Bacterial Agents; D020126:Brefeldin A; D003517:Cyclopentanes; D016207:Cytokines; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D006131:Growth Inhibitors; D015850:Interleukin-6; D018942:Macrolides; D008985:Monensin; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D000093242:Interleukin-6 Inhibitors