ABSTRACT
The inhibitory effect of Zingiber officinale Rosc (ZOR), an Oriental traditional herbal medicine, on the growth of influenza A/Aichi/2/68 (Aichi) virus was investigated in Madin-Darby canine kidney (MDCK) cells. Direct addition of ZOR (0.1 approximately 100 microg/ml) to the infected cells did not have any inhibitory effect. However, the ZOR-induced conditioned medium (ZOR-CM) of RAW cells, a murine macrophage (Mphi) cell line, exhibited an apparent inhibitory effect on MDCK cells without cytotoxicity. In accordance with the time-dependent inhibitory effect of ZOR-CM, it has been demonstrated that tumor necrosis factor (TNF)-alpha was gradually accumulated in ZOR-CM by the induction of TNF-alpha mRNA expression in ZOR-stimulated RAW cells. Conversely, the inhibitory effect of ZOR-CM was reduced significantly by the removal of TNF-alpha after the formation of an immune complex with anti-TNF-alpha monoclonal antibody. These data suggested that ZOR itself has no inhibitory effect on the growth of influenza virus, but could exert its effect via macrophage activation leading to production of TNF-alpha.
Subject(s)
Drugs, Chinese Herbal/pharmacology , Influenza A Virus, H3N2 Subtype/drug effects , Zingiber officinale , Animals , Antibodies, Monoclonal , Cell Line , Dogs , Dose-Response Relationship, Drug , Lipopolysaccharides/pharmacology , Macrophages/drug effects , Mice , RNA, Messenger/metabolism , Time Factors , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/metabolismABSTRACT
We investigated the inductive activity of infective influenza A/PR/8/34 (PR8) virus and its ether-split product (ESP) on the expression of inducible nitric oxide (NO) synthase (iNOS) and NO production in RAW264.7 (RAW) cells, a murine macrophage (M psi) cell line, and thioglycolate-elicited peritoneal M psi (TPM). In both cells, PR8 virus infection induced iNOS mRNA between 4 hr and 24 hr, attaining a peak value at 12 hr. In correlation with induction of iNOS mRNA, NO amounts increased significantly from 12 to 24 hr. Moreover, this study demonstrated that ESP with the same hemagglutination titer as PR8 virus could induce iNOS mRNA and NO production, although the inductive activity of ESP was weaker than that of PR8 virus. Considering the dual role (beneficial and detrimental roles) of NO on certain inflammatory disorders and virus infections, the inductive activity of influenza virus on the iNOS-mediated NO production independent of its infectivity might contribute to a modification of influenza virus infection.
Subject(s)
Macrophages/metabolism , Macrophages/virology , Nitric Oxide Synthase/biosynthesis , Nitric Oxide/biosynthesis , Orthomyxoviridae/immunology , Viral Proteins/immunology , Animals , Cell Line , Gene Expression Regulation , Macrophages/enzymology , Mice , Nitric Oxide/analysis , Nitric Oxide Synthase/genetics , Nitric Oxide Synthase Type II , Orthomyxoviridae/physiology , RNA, Messenger/analysis , Transcription, Genetic , Viral Proteins/isolation & purification , Viral Proteins/physiologyABSTRACT
We have investigated the effect of Zingiber offifinale Rosc. (ZOR) on macrophage-inducible nitric oxide (NO) synthase (macNOS) mRNA expression and NO production in RAW264.7 cells, a murine macrophage cell line; 100 microg/ml ZOR can induce macNOS mRNA expression, but induction effects at a dose below 10 microg/ml were weak or negligible. Kinetic studies showed that macNOS mRNA can be detected from 4 hours to 24 hours after dosing, with a peak at 8 hours. In accordance with the induction of macNOS mRNA expression, NO concentrations increased from 3.4 microM at 2 hours to almost 150 microM at 24 hours, reflecting a longer period of macNOS mRNA expression. The activity of ZOR can be considered to contribute, at least in part, to the beneficial effects of ZOR through the macNOS-mediated activation of the biodefense mechanism.
