Granulocyte-macrophage colony-stimulating factor mRNA stabilization enhances transgenic expression in normal cells and tissues

To increase transgenic production of granulocyte-macrophage colony- stimulating factor (GM-CSF), we mutated the mRNA's 3'-untranslated region, AUUUA instability elements. Expression vectors containing human or murine GM-CSF cDNAs coding for wild-type (GM-AUUUA) or mutant versions with reiterated AUGUA repeats (GM-AUGUA) were transfected into cells in culture or animals using particle-mediated gene-transfer technology. Normal peripheral blood mononuclear cells accumulated 20- fold greater levels of GM-CSF mRNA and secreted comparably greater amounts of cytokine after transfection with hGM-AUGUA expression vectors versus hGM-AUUUA. hGM-AUGUA mRNA was fivefold more stable (t 1/2 = 95 minutes) than hGM-AUUUA mRNA (t 1/2 = 20 minutes), accounting for elevated steady-state levels. Transfection site extracts and serum samples obtained 24 hours after gene transfer of hGM-AUGUA cDNA into mouse skin contained greater than 32 ng/mL and 650 pg/mL of GM-CSF protein, respectively, compared with 0.33 ng/mL and less than 8 pg/mL for hGM-AUUUA cDNA. GM-CSF produced from mGM-AUGUA cDNA transfected into rat abdominal epidermis induced a profound neutrophil infiltrate. These data suggest a novel strategy for enhanced production of biologically active cytokines by normal cells after in vivo gene transfer.     

牛蒡子化学成分的研究

从牛蒡(Arctium lappa L.)子乙醚和丙酮提取物中,经硅胶柱层析,低压柱层析和制备性薄层层析分离到一个甾体化合物,胡萝卜甙(daucosterol,Ⅰ)和四个已知木脂素:牛蒡子甙元(arctigenin,Ⅱ)、牛蒡子甙(arctiin,Ⅲ)、罗汉松脂素(matairesinol,Ⅳ)和牛蒡酚F(lappaol F,Ⅴ)。一个新木脂素,命名为新牛蒡素乙(neoarctin B,Ⅵ)。根据光谱(UV,IR,¹H-NMR,¹³C-NMR,DEPT,2D-NMR和MS)分析,推定了其化学结构为式Ⅵ。