Effect of vitamin E on production of macrophage migration inhibitory factor (MIF) by macrophages.
Macrophage migration inhibitory factor (MIF), a putative cytokine involved in inflammatory and immune responses, was identified in rat peritoneal macrophages by Western blot analysis and its secretion into culture medium by enzyme-linked immunosorbent assay. To clarify the possibility of vitamin E as an immune modulator, we investigated the effect of vitamin E on MIF production in macrophages in response to calcium ionophore A23187 and lipopolysaccharide (LPS). Intraperitoneal injections of vitamin E (5 mg per rat) for 6 successive days resulted in a significant increase of alpha-tocopherol content in peritoneal macrophages. Alpha-tocopherol content of macrophages in vitamin E-treated rats was 478.3 +/- 90.7 ng/10(6) cells, whereas in control rats it was 1.5 +/- 0.5 ng/10(6) cells. For the control macrophages, total MIF content of the medium (2.5 x 10(6) cells/18 ml) without stimulation was 40.7 +/- 3.6 ng after 14 h culture, whereas stimulation with calcium ionophore A23187 (400 nM) and LPS (5.0 microg/ml) induced the elevation of MIF content to 65.9 +/- 7.5 ng and 74.3 +/- 10.4 ng, respectively (p < 0.05, n = 3). On the other hand, vitamin E-enriched macrophages without stimulation showed less MIF content (14.0 +/- 4.2 ng) than the control (p < 0.05, n = 3). Similarly, the increase of MIF of vitamin E-treated macrophages was significantly suppressed after stimulation with calcium ionophore A23187 or LPS, compared with the control macrophages (p < 0.01, n = 3). From analysis of intracellular MIF content by Western blot, we found no alteration of intracellular MIF content of vitamin E-macrophages, in contrast to the decreased content of control stimulated-macrophages, showing that vitamin E suppressed MIF secretion into the culture medium. Taken together, these results indicate that vitamin E may contribute to the regulation of inflammatory and immune responses through regulation of MIF secretion, possibly by modulating macrophage-membrane architecture.
Sakamoto
W
W
Department of Biochemistry, School of Dentistry, Hokkaido University, Sapporo, Japan. sakamoto@den.hokudai.ac.jp
Nishihira
J
J
Fujie
K
K
Iizuka
T
T
Handa
H
H
Ozaki
M
M
Yukawa
S
S
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D048429:Cell Size; D002470:Cell Survival; D002478:Cells, Cultured; D007700:Kinetics; D008070:Lipopolysaccharides / Q000494:pharmacology; D008263:Macrophage Migration-Inhibitory Factors / Q000096:biosynthesis* / Q000378:metabolism; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D014810:Vitamin E / Q000494:pharmacology*
D008070:Lipopolysaccharides; D008263:Macrophage Migration-Inhibitory Factors; D014810:Vitamin E; D000001:Calcimycin