The mechanism for synthesis and secretion of apo A-IV in CaCo-2 cells

人类apo A-IV是一种独特的apolipoprotein，它只在电子细胞中合成，并在脂质吸收中加入。However，Apo A-IV合成和秘密的机制并没有完全解释。在这项研究中，两种脂肪酸、橄榄酸（C-D 218：1-D2）和Caprylic （C-D 28：0-D2）酸的影响在CaCo-2细胞中进行了测试。CaCo-2细胞，它们是从人类结肠癌细胞中产生的细胞线，并显示出内部表皮的特征，在37℃下过滤器膜上培养了6小时，含有3.0 mM的橄榄酸或毛细管酸。橄榄酸增加了三聚氰胺保密4次，而胶囊酸增加了1.3次，比较到控制。Apo A-IV浓度在中间明显地减少在橄榄酸中，与Caprylic酸进行比较。在对比中，细胞中的apo A-IV mRNA水平明显增加，与橄榄酸相比。有人建议，在没有合成和橄榄酸增加的情况下，将脂蛋白A-IV的含量提高到脂蛋白A-IV的转录率，至少在CaCo-2细胞中。脂肪酸对apo A-IV的不同影响对脂肪酸的不同碳数。

Human apo A-IV is an unique apolipoprotein which is synthesized only in enterocytes and is involved in lipid absorption. However, the mechanism for synthesis and secretion of apo A-IV has not been fully explored. In this study, the effect of two kinds of fatty acid, oleic (CィイD218:1ィエD2) and caprylic (CィイD28:0ィエD2) acids, on apo A-IV synthesis and sedretion was examined in CaCo-2 cells. CaCo-2 cells, which are cell line origenated from human colon cancer cells and show characteristics of intestinal epithelim, were cultured on the filter mambrane of Transwell for 6 hr at 37℃ with 3.0 mM of oleic or caprylic acid with a micellar form. Oleic acid increased triglyceride secretion by 4 times, whereas caprylic acid increased by 1.3 times, compared to control. Apo A-IV concentration in the medium was significantly decreased in oleic acid, compared to caprylic acid. In contrast, apo A-IV mRNA level in cells is significantly increased in oleic acid compared to caprylic acid. It is suggested that caprylic acid enhances the secretion of apo A-IV without the increase in synthesis and oleic acid increases the transcription rate of apo A-IV, at least in CaCo-2 cells. These different effects of fatty acids on apo A-IV depends on the different carbon number of fatty acids.