miR-17 is involved in the regulation of LC-PUFA biosynthesis in vertebrates: effects on liver expression of a fatty acyl desaturase in the marine teleost Siganus canaliculatus.
miR-17 is involved in the regulation of LC-PUFA biosynthesis in vertebrates: effects on liver expression of a fatty acyl desaturase in the marine teleost Siganus canaliculatus.
复制标题
DOI：
10.1016/j.bbalip.2014.03.009
复制
发表时间：
2014-07
期刊：
影响因子：
--
通讯作者：
Qinghao Zhang;Dizhi Xie;Shuqi Wang;C. You;Ó. Monroig;D. Tocher;Yuanyou Li
中科院分区：
文献类型：
--
作者：
Qinghao Zhang;Dizhi Xie;Shuqi Wang;C. You;Ó. Monroig;D. Tocher;Yuanyou Li
在脊椎动物中，长链多不饱和脂肪酸（LC-PUFA）如花生四烯酸（ARA; 20：4 n − 6）、二十碳五烯酸（EPA; 20：5 n − 3）和二十二碳六烯酸（DHA; 22：6 n − 3）的生物合成需要脂肪酰去饱和酶（Fads）的催化。在海洋硬骨鱼长鳍蓝子鱼（Siganus canaliculatus）中发现了一种具有Δ4活性的脊椎动物Fad，可以催化22：5 n − 3直接转化为DHA。最近在脊椎动物中的研究表明，miRNA可能在转录后水平参与脂质代谢的调节。然而，它们在LC-PUFA生物合成中的作用尚不清楚。在本研究中，我们通过计算机模拟分析，预测了兔鱼Δ4 Fad可能是miR-17的作用靶点，并克隆了位于miR-17-92簇的前半部分的miR-17。双荧光素酶报告基因检测表明，miR-17直接靶向Δ4 Fad的3′UTR。此外，miR-17在鳃、肝脏和眼中的表达水平与Δ4 Fad mRNA的表达水平呈负相关，在肝脏中的表达水平与Δ4 Fad蛋白的表达水平呈负相关。用亚油酸（LA; 18：2n − 6）、α-亚麻酸（LNA; 18：3 n − 3）、EPA或DHA孵育兔鱼原代肝细胞，对miR-17、Δ4 Fad和Δ6/Δ5 Fad表达的影响不同。LNA促进miR-17和Δ6/Δ5 Fad的表达，但抑制Δ4 Fad的表达。LA和EPA降低miR-17和Δ6/Δ5 Fad的表达，但对Δ4 Fad无影响。然而，所有这些都被DHA下调。这些数据表明miR-17通过靶向Δ4 Fad参与了兔鱼肝脏LC-PUFA生物合成的调控。
Biosynthesis in vertebrates of long-chain polyunsaturated fatty acids (LC-PUFA) such as arachidonic (ARA; 20:4n − 6), eicosapentaenoic (EPA; 20:5n − 3) and docosahexaenoic (DHA; 22:6n − 3) acids requires the catalysis by fatty acyl desaturases (Fads). A vertebrate Fad with Δ4 activity catalyzing the direct conversion of 22:5n − 3 to DHA was discovered in the marine teleost rabbitfishSiganus canaliculatus. Recent studies in vertebrates have shown that miRNAs may participate in the regulation of lipid metabolism at post-transcription level. However, their roles in LC-PUFA biosynthesis were not known. In the present study,in silicoanalysis predicts that the rabbitfish Δ4 Fad may be a target of miR-17 and thus we cloned miR-17, which is located at the forepart of the miR-17–92 cluster. Dual luciferase reporter assays demonstrated that miR-17 targeted the 3′UTR of Δ4 Fad directly. Furthermore, the expression level of miR-17 displayed an inverse pattern with that of Δ4 Fad mRNA in gill, liver and eyes, and also the Δ4 Fad protein quantity in rabbitfish liver. Incubation of rabbitfish primary hepatocytes with linoleic acid (LA; 18:2n − 6), α-linolenic acid (LNA; 18:3n − 3), EPA or DHA showed differential effects on miR-17, Δ4 Fad and Δ6/Δ5 Fad expression. LNA promoted the expression of miR-17 and Δ6/Δ5 Fad, but suppressed the expression of Δ4 Fad. In contrast, LA and EPA decreased the expression of miR-17 and Δ6/Δ5 Fad, but had no effect on Δ4 Fad. However, all the above were down-regulated by DHA. These data indicate that miR-17 was involved in the regulation of LC-PUFA biosynthesis in rabbitfish liver by targeting Δ4 Fad.