SUMMARY:To examine whether synovial cell proliferation is due to angiogenesis, we studied the relationship between the inhibition of synovial cell proliferation and an angiogenesis inhibitor, TNP-470, in human synovial tissues. Human synovial tissues were implanted into the back of SCID mice (SCID-HuAg mice). Sixteen mice were divided into two groups of eight mice each: the untreated group (vehicle group) and the TNP-470-treated group that received a dose of 10 mg/kg body weight by subcutaneous injection. The number of blood vessels and synovial lining cells clearly increased in the vehicle group, but the number of synovial lining cells clearly decreased and the blood vessels were hardly detected in the TNP-470 group. Immunohistochemically, cells that stained positively for the anti-proliferating cell nuclear antigen (PCNA) mAb were abundant in synovial lining cells and endothelial cells in synovial tissues. Cells that stained positively for the anti-CD34 polyclonal antibody were abundant in the endothelial cells in the vehicle group, but these positively stained cells were hardly detected in the TNP-470 group. The PCNA positivity ratio in the vehicle group was 0.64 Ϯ 0.019, whereas that in the TNP-470 group was 0.199 Ϯ 0.007. The numbers of cells that stained positively for anti-CD34 polyclonal antibody were 242 Ϯ 13.4 in the vehicle group and 153 Ϯ 6.73 in the TNP-470 group per 10 microscopic fields. Cells that stained positively for anti-mouse CD31 mAb were mainly localized in the synovial lining, but invaded the subsynovial lining layer in human synovial tissues. On the other hand, cells that stained positively for anti-human CD31 mAb were mainly localized in the subsynovial lining layer. We found that endothelial cell proliferation is dependent on angiogenesis based on the result that angiogenesis and synovial cell proliferation were inhibited by treatment with TNP-470. (Lab Invest 2002, 82:981-988).
The glucocorticoid receptor regulates gene expression mainly by two mechanisms; transactivation and transrepression. A ligand with strong transrepression and weak transactivation activity is predicted to be a beneficial agent with potent anti-inflammatory activity and minor adverse effects. Recently, the profile of a synthetic steroid, RU24858, has been reported to fulfill this condition in vitro, but others have reported no dissociation between the anti-inflammatory activity and side effects in vivo. To gain further information on the profile of this compound, we evaluated its transactivation ability using a reporter gene analysis both in vitro and in vivo. In the in vitro analysis, RU24858 demonstrated only a weak transactivation activity in HeLa cells, when compared with prednisolone. In CV-1 cells, however, these two glucocorticoids exhibited equivalent transactivation activities. This behavior is independent of whether the reporter gene is regulated by mouse mammary tumor virus promoter or multiple copies of glucocorticoid response element. When the reporter plasmid was inoculated into mouse abdominal skin using a gene gun, followed by orally administration of glucocorticoids, RU24858 induced significantly higher reporter enzyme activity than prednisolone. These results suggest that the profile of RU24858 is divergent and its transactivation ability is comparable to prednisolone depending on the cell-type both in vitro and in vivo.
Non-alcoholic fatty liver disease is strongly associated with obese and type 2 diabetes. It has been reported that an oxidized cholesterol, 7-ketocholesterol (7KC), might cause inflammatory response in macrophages and plasma 7KC concentration were higher in patients with cardiovascular diseases or diabetes. Therefore, we have decided to test whether small amount of 7KC in diet might induce hepatic steatosis and inflammation in two types of obese models. We found that addition of 0.01% 7KC either in chow diet (CD, regular chow diet with 1% cholesterol) or western type diet (WD, high fat diet with 1% cholesterol) accelerated hepatic neutral lipid accumulation by Oil Red O staining. Importantly, by lipid extraction analysis, it has been recognized that triglyceride rather than cholesterol species was significantly accumulated in CD+7KC compared to CD as well as in WD+7KC compared to WD. Immunostaining revealed that macrophages infiltration was increased in CD+7KC compared to CD, and also in WD+7KC compared to WD. These phenotypes were accompanied by inducing inflammatory response and downregulating fatty acid oxidation. Furthermore, RNA sequence analysis demonstrated that 7KC reduced expression of genes which related to autophagy process. Levels of LC3-II protein were decreased in WD+7KC compared to WD. Similarly, we have confirmed the effect of 7KC on acceleration of steatohepatitis in db/db mice model. Collectively, our study has demonstrated that small amount of dietary 7KC contributed to accelerate hepatic steatosis and inflammation in obese mice models.
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