Ethyl acetate fraction from Cudrania tricuspidata inhibts IL-1β-induced rheumatoid synovial fibroblast proliferation and MMPs, COX-2 and PGE2 production

Objectives: The objective of this study is to determine the effects of Ethyl acetate fraction from Cudrania tricuspidata (EACT) on the interleukin-1b (IL-1b)-induced proliferation of rheumatoid synovial fbroblasts (RASFs) and production of matrix metalloproteinases (MMPs), cyclooxygenase (COX) and prostaglandin E2 (PGE2) by RASFs. Materials and Methods: The proliferation of RASFs was evaluated with CCK-8 reagent in the presence of IL-1b with/without EACT. The expression of MMPs, TIMP-1, COXs, PGE2 and intracellular MAPK signalings, including p-ERK, p-p38, p-JNK and NF-kB were examined by immunoblotting or semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and ELISA in conditions as described above. Results: EACT inhibits IL-1β-induced proliferation of RASFs and MMP-1, 3, COX-2 mRNA and protein expression, PGE2 production induced with IL-1b. EACT also inhibits the phosphorylation of ERK-1/2, p38, JNK and activation of NF-kB by IL-1b. Conclusions: These results suggest that EACT might be involved in synovial fbroblast proliferation and MMPs, COX-2, and PGE2 production, which are involved in joint destruction in rheumatoid arthritis (RA), indicating that this might be a new therapeutic modality for management of rheumatoid arthritis.

Tissue mRNA expression in rat of newly described matrix metalloproteinases

Matrix metalloproteinases (MMPs) comprise a large group of endoproteinases that degrade all protein components of the extracellular matrix. Functionally, MMPs contribute to several different physiological as well as pathological conditions. The number of newly described MMPs has increased in recent years, although current knowledge about their expression pattern in various tissues remains incomplete. Here we analyzed the relative mRNA expression of the most recently described MMPs _ MT5-MMP (MMP-24), MT6-MMP (MMP-25), MMP-27 and epilysin (MMP-28) _ in a broad selection of rat tissues using real time-PCR. MMP-24 mRNA was found to be widely expressed with predominance in the central nervous system. MMP-25 mRNA, in contrast, exhibited peak expression levels in testis, kidney and skeletal muscle, differing from previously described distribution patterns in humans. mRNAs for MMP-27 and MMP-28 were generally expressed at a lower level. All four MMPs studied were detected at higher mRNA levels in bone and kidney, suggesting a possible role of these MMPs in physiological processes within these two organs. The present study highlights the differential distribution pattern of newly described MMPs among different tissues and underlines differences in the mRNA expression between different species.

Potential role of leptin in angiogenesis: leptin induces endothelial cell proliferation and expression of matrix metalloproteinases in vivo and in vitro

Leptin, the product of ob gene, is an endocrine hormone that regulates adipose tissue mass. Recently, leptin has been found to generate a growth signal involving a tyrosine kinase-dependent intracellular pathway and promote angiogenic processes via activation of leptin receptor (Ob-R) in endothelial cells. However, it is not clear how leptin functions to promote multi-step processes involved in the neovascularization at the atherosclerotic plaque. We have examined the expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) and Ob-R in human atherosclerotic lesions, leptin-mediated angiogenesis in vivo and in vitro. Immunohistochemical analysis of human atherosclerotic aorta revealed an increased expression of Ob-R in the intima of neorevascularized regions and of both MMPs and TIMPs predominantly in the endothelial lining of intimal neovessels and macrophages/foam cells. In the rat corneal angiogenesis assay, leptin elicited a comparable sensitivity of angiogenic activity to those of vascular endothelial growth factor (VEGF). The immunohistological analysis of the leptin-treated rat cornea showed definitive rises in Ob-R, MMPs and TIMPs expression as well as those of VEGF receptor (VEGFR-1). Leptin (10-40 ng/ml) induced proliferation of the human umbilical vein endothelial cells (HUVECs) and elevation of MMP-2, MMP-9, TIMP-1, and TIMP-2 expression in a dose-dependent manner. Leptin also induced increases of MMP-2, MMP-9, TIMP-1, and Up-regulated the human coronary artery smooth muscle cells (HCASMCs). These findings suggest that leptin, a hormone with pluralistic properties including a mitogenic activity on vascular endothelial cells, plays a role in matrix remodeling by regulating the expression of MMPs and TIMPs. Taken together, our findings further provide evidences for leptin's role as an angiogenesis inducer in the normal organ (rat cornea) and in aberrant vasculature under duress like atherosclerosis.