Many mechanisms involving TNF-α, Th1 responses, and Th17 responses are implicated in chronic inflammatory autoimmune disease. Recently, the clinical impact of anti-TNF therapy on disease progression has resulted in re-evaluation of the central role of this cytokine and engendered novel concept of TNF-dependent immunity. However, the overall relationship of TNF-α to pathogenesis is unclear. Here, we demonstrate a TNF-dependent differentiation pathway of dendritic cells (DC) evoking Th1 and Th17 responses. CD14+ monocytes cultured in the presence of TNF-α and GM-CSF converted to CD14+ CD1alow adherent cells with little capacity to stimulate T cells. On stimulation by LPS, however, they produced high levels of TNF-α, matrix metalloproteinase (MMP)-9, and IL-23 and differentiated either into mature DC or activated macrophages (Mφ). The mature DC (CD83+ CD70+ HLA-DR high CD14low) expressed high levels of mRNA for IL-6, IL-15, and IL-23, induced naive CD4 T cells to produce IFN-γ and TNF-α, and stimulated resting CD4 T cells to secret IL-17. Intriguingly, TNF-α added to the monocyte culture medium determined the magnitude of LPS-induced maturation and the functions of the derived DC. In contrast, the Mφ (CD14highCD70+CD83−HLA-DR−) produced large amounts of MMP-9 and TNF-α without exogenous TNF stimulation. These results suggest that the TNF priming of monocytes controls Th1 and Th17 responses induced by mature DC, but not inflammation induced by activated Mφ. Therefore, additional stimulation of monocytes with TNF-α may facilitate TNF-dependent adaptive immunity together with GM-CSF-stimulated Mφ-mediated innate immunity.

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Several tea polyphenols, particularly those containing galloyl, have antitumor affects via strong antioxidant and antiangiogenic activities. Theaflavin-3,3'-digallate (TF3), a theaflavin derivative in black tea, has 2 galloyl groups. Matrix metalloproteinases (MMPs) are associated with extracellular matrix degradation, cellular migration, and angiogenesis, and (-)-epigallocatechin-3-gallate (EGCG) is an inhibitor of MMP activity and secretion; thus one of its major actions is the inhibition of angiogenesis. However, there are few studies of angiogenesis in theaflavin derivatives. We investigated the effects of TF3 on angiogenesis in vitro. Angiogenesis was assayed using cocultured human umbilical vein endothelial cells with fibroblasts. Cells were cultivated in various concentrations of TF3 and EGCG in the presence or absence of vascular endothelial growth factor-A. After 11 days, MMP-2 and MMP-9 activities and the pro-MMP-2 protein in the medium were measured by gelatin zymography and immunoassay, respectively. Tube formation was markedly inhibited by 100 umol/L TF3 or EGCG. Even at 10 iumolIL, TF3 or EGCG inhibited tube formation. The MMP-2 and MMP-9 activities were inhibited and pro-MMP-2 protein concentrations were reduced by TF3 or EGCG in a concentration-dependent manner, regardless of the presence of vascular endothelial growth factor. The effect of TF3 was similar to that of EGCG, indicating that the tube formation of endothelial cells was suppressed via decreased both MMP-2 and MMP-9 activities in vitro. Our results demonstrate antiangiogenic activity of TF3 in vitro, and suggest possible anti-tumor effects of TF3.

: Matrix metalloproteinases (MMPs) contribute to cardiovascular disease and are associated with vascular lesions in diabetes mellitus. In the present in vivo study, we investigated whether oral administration of green tea changes the mRNA expression of MMPs in diabetic rats, because green tea catechins inhibit mRNA expression and activity of MMPs in vitro. Experimental diabetes was induced in rats by a single injection of 50 mg / kg streptozotocin (STZ) into the tail vein. Diabetic rats were fed either a green tea-free diet (STZ rats) or a diet containing 5 % green tea (STZ + GT rats) for 4 weeks. Control rats are non-diabetic rats not treated with green tea. The mRNA expression of MMP-2, MN'IP-9, tissue inhibitor of metalloproteinases (TIMP) -1, TIMP-2, and TIMP-3 in rat liver and kidney was determined by real-time polymerase chain reaction. In the liver, there were no significant differences in the mRNA expression of MMP-2, MMP-9, TIMP-1, and TIMP-2 between STZ rats and STZ + GT rats. However, TIMP-3 mRNA expression in the liver was significantly increased in STZ + GT rats compared with control and STZ rats. In the kidney, MMP-9 mRNA expression in STZ rats was significantly decreased compared with that in control rats, whereas that in STZ + GT rats recovered to levels the same as in control rats. MMP-2, TIMP-1, TIMP-2 and TIMP-3 mRNA expression in the kidney were significantly increased in STZ + GT rats compared with STZ rats. Thus, 5 % green tea treatment of STZ diabetic rats improved changes in the mRNA expression of MMPs and TIMPs in kidney tissue more efficiently than in the liver. The results of the present study suggest that the imbalance in the mRNA expression of MMPs and TIMPs in STZ diabetic rats is improved by green tea treatment.

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