The role of lipid droplet formation in the protection of unsaturated fatty acids against palmitic acid induced lipotoxicity to rat insulin-producing cells.
The role of lipid droplet formation in the protection of unsaturated fatty acids against palmitic acid induced lipotoxicity to rat insulin-producing cells.
复制标题
DOI：
10.1186/s12986-016-0076-z
复制
发表时间：
2016
影响因子：
4.5
通讯作者：
Elsner M
中科院分区：
文献类型：
--
作者：
Plötz T;Hartmann M;Lenzen S;Elsner M
2型糖尿病与非酯化脂肪酸（NEFA）的血浆浓度增加相关，其触发胰腺β细胞功能障碍和细胞凋亡。在体外实验中，只有长链饱和NEFA诱导大鼠胰岛素产生细胞的脂毒性，而不饱和NEFA没有毒性。一些不饱和NEFA甚至可以防止脂毒性。在以前的研究中，有人提出，长链不饱和NEFA，诱导形成的脂滴，可以导致螯合棕榈酸进入脂滴。在本构效关系研究中，研究了脂滴形成与不饱和NEFA在大鼠胰岛素产生细胞中对棕榈酸诱导的脂毒性的保护之间的相关性。在棕榈酸和具有不同链长和不同双键数量的不饱和NEFA的存在下孵育大鼠产胰岛素RINm 5 F和INS-1 E组织培养细胞。通过shRNA技术抑制脂滴相关蛋白perilipin 1和perilipin 2的表达，并通过qRT-PCR和Western blotting分析表达。MTT法测定细胞活力，油红O染色后荧光显微镜下观察脂滴的聚集情况。长链不饱和NEFA强烈诱导大鼠胰岛素产生RINm 5 F和INS-1 E细胞中脂滴的形成。在与11-二十碳烯酸（C20：1）孵育的RINm 5 F细胞中，27%的细胞面积被脂滴覆盖，与对照细胞相比增加了25倍。另一方面，饱和NEFA棕榈酸仅诱导少量脂滴形成。活力分析显示，只有轻微的毒性不饱和NEFA，而细胞显着敏感的棕榈酸。长链不饱和NEFA拮抗棕榈酸诱导的脂毒性在共孵育过程中，从而没有相关性之间存在的保护和脂滴形成的能力。在与C20：1孵育后，通过shRNA将周脂蛋白1和2的表达降低至约80%。对于长链不饱和NEFA对饱和NEFA脂毒性的保护作用，周脂蛋白的抑制并不至关重要。长链不饱和脂肪酸保护大鼠胰岛素分泌细胞免受饱和脂肪酸的脂毒性。这种保护作用不依赖于脂滴的形成。因此，脂滴形成显然不是不饱和NEFA对抗棕榈酸毒性的保护作用所必需的。本文的在线版本（doi：10.1186/s12986-016-0076-z）包含补充材料，可供授权用户使用。
Type 2 diabetes is associated with increased plasma concentrations of non-esterified fatty acids (NEFAs), which trigger pancreatic β-cell dysfunction and apoptosis. Only long-chain saturated NEFAs induced lipotoxicity in rat insulin-producing cells in in vitro experiments, whereas unsaturated NEFAs were not toxic. Some unsaturated NEFAs even protected against lipotoxicity. In former studies it was suggested that long-chain unsaturated NEFAs, which induce the formation of lipid droplets, can cause sequestration of palmitic acid into lipid droplets. In the present structure-activity-relationship study the correlation between lipid droplet formation and the protection against palmitic acid induced lipotoxicity by unsaturated NEFAs in rat insulin-producing cells was examined. Rat insulin-producing RINm5F and INS-1E tissue culture cells were incubated in the presence of palmitic acid and unsaturated NEFAs with different chain lengths and different numbers of double bonds. The expression of the lipid droplet associated proteins perilipin 1 and 2 was repressed by the shRNA technique and the expression analyzed by qRT-PCR and Western blotting. Viability was measured by MTT assay and the accumulation of lipid droplets was quantified by fluorescence microscopy after Oil Red O staining. Long-chain unsaturated NEFAs strongly induce the formation of lipid droplets in rat insulin-producing RINm5F and INS-1E cells. In RINm5F cells incubated with 11-eicosenoic acid (C20:1) 27 % of the cell area was covered by lipid droplets corresponding to a 25-fold increase in comparison with control cells. On the other hand the saturated NEFA palmitic acid only induced minor lipid droplet formation. Viability analyses revealed only a minor toxicity of unsaturated NEFAs, whereas the cells were markedly sensitive to palmitic acid. Long-chain unsaturated NEFAs antagonized palmitic acid induced lipotoxicity during co-incubation, whereby no correlation existed between protection and the ability of lipid droplet formation. Perilipin 1 and 2 expression was decreased after incubation with C20:1 to about 80 % by shRNA. For the protective effect of long-chain unsaturated NEFAs against lipotoxicity of saturated NEFAs repression of perilipin was not of crucial importance. Long-chain unsaturated fatty acids protected rat insulin-producing cells against lipotoxicity of saturated fatty acids. This protective effect was not dependent on lipid droplet formation. Thus lipid droplet formation is apparently not essential for the protective effect of unsaturated NEFAs against palmitic acid toxicity. The online version of this article (doi:10.1186/s12986-016-0076-z) contains supplementary material, which is available to authorized users.