Key Whang

Melittin has an inhibitory effect on TNF-α-induced migration of human aortic smooth muscle cells by blocking the MMP-9 expression.

Matrix metalloproteinases-9 (MMP-9) plays an important role in the pathogenesis of atherosclerosis and migration of vascular smooth muscle cells (VSMCs) after an arterial injury. In this study, we investigated the potential molecular mechanisms underlying the anti-atheroscleroic effects of melittin, a major component of bee venom, in human aortic smooth muscle cells (HASMCs). Melttin significantly suppressed MMP-9 and MMP-2 secretion, as well as TNF-α-induced MMP-9 expression in the HASMCs. In addition, we found that the inhibitory effects of melittin on TNF-α-induced MMP-9 protein expression are associated with the inhibition of MMP-9 transcription levels. Mechanistically, Melittin suppressed TNF-α-induced MMP-9 activity by inhibiting the phosphorylation of p38 and ERK1/2, but did not affect the phosphorylation of JNK and Akt. Reporter gene and western blotting assays showed that melittin inhibits MMP-9 transcriptional activity by blocking the activation of NF-κB via IκBα signaling pathway. Moreover, the matrigel migration assay showed that melittin reduced TNF-α-induced HASMC migration. These results suggest that melittin suppresses TNF-α-induced HASMC migration through the selective inhibition of MMP-9 expression and provide a novel role of melittin in the anti-atherosclerotic action.

Inhibitory Effects of Lyophilized Dropwort Vinegar Powder on Adipocyte Differentiation and Inflammation

Obesity, which is characterized by a state of mild chronic inflammation, is known to cause metabolic diseases. This study was carried out to investigate the effect of lyophilized dropwort vinegar powder (DVP) on adipocyte differentiation and inflammation in T3-L1 preadipocyte and RAW 264.7 macrophage cell lines. DVP inhibited the differentiation of 3T3-L1 preadipocytes induced by a mixture of IBMX, dexamethasone, and insulin (MDI). Western blot analysis of cell lysates showed that DVP decreased the levels of two major transcription factors involved in adipogenesis, peroxisome proliferator-activated receptor-γ (PPAR-γ) and CCAAT-enhancer-binding protein α (C/EBPα). DVP also significantly suppressed lipopolysaccharide (LPS)-induced production of nitric oxide (NO), and this was accompanied by a decrease in inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression. These results demonstrate that DVP inhibits MDI-induced adipocyte differentiation of 3T3-L1 cells and LPS-induced inflammation in RAW 264.7 macrophage cells. The findings indicate that this natural product may be a good candidate as to prevent metabolic diseases.