HADHA, the alpha subunit of the mitochondrial trifunctional protein, is involved in long-chain fatty acid-induced autophagy in intestinal epithelial cells
HADHA, the alpha subunit of the mitochondrial trifunctional protein, is involved in long-chain fatty acid-induced autophagy in intestinal epithelial cells
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DOI：
10.1016/j.bbrc.2017.01.159
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发表时间：
2017-03-11
影响因子：
3.1
通讯作者：
Watanabe, Mamoru
中科院分区：
文献类型：
--
作者：
Maeyashiki, Chiaki;Oshima, Shigeru;Watanabe, Mamoru
全基因组关联研究已经确定了炎症性肠病（IBD）的自噬相关易感基因;然而，自噬调节剂是否可以用作治疗靶点仍不清楚。为了鉴定新的微管相关蛋白1轻链3（LC 3）相互作用的蛋白质在肠上皮细胞（IEC），我们分离的原代IEC从绿色荧光蛋白（GFP）-LC 3小鼠。我们用GFP抗体进行免疫沉淀，然后通过质谱分析共免疫沉淀物。HADHA被鉴定为来自原代IEC的LC 3相互作用蛋白。HADHA基因编码线粒体三功能蛋白的α亚基。鉴于HADHA催化长链脂肪酸的线粒体β-氧化的最后三个步骤，我们研究了长链脂肪酸是否诱导IEC中的自噬。我们发现棕榈酸诱导DLD-1、HT 29和HCT 116细胞的自噬。HADHA不仅在线粒体中表达，而且在胞浆中也有表达。LC 3斑点与HADHA共定位，其通过棕榈酸刺激增强。然而，LC 3斑点不与Tom 20共定位，表明HADHA被诱导与LC 3斑点在线粒体以外的位点缔合。因此，HADHA可能具有线粒体外功能。此外，我们发现棕榈酸诱导IEC细胞死亡，这是加速巴夫洛霉素A和氯喹。这些发现表明棕榈酸诱导的自噬支持IEC的存活。总之，这些结果表明，HADHA参与了IEC中长链脂肪酸诱导的自噬，从而为IBD的病理学提供了新的见解，并揭示了IBD的新治疗靶点。(C)2017爱思唯尔公司All rights reserved.
Genome-wide association studies have identified autophagy-related susceptibility genes for inflammatory bowel disease (IBD); however, whether autophagy regulators can be utilized as therapeutic targets remains unclear. To identify novel microtubule-associated protein 1 light chain 3 (LC3)-interacting proteins in intestinal epithelial cells (IECs), we isolated primary IECs from green fluorescent protein (GFP)-LC3 mice. We performed immunoprecipitation with a GFP antibody and then analyzed co-immunoprecipitates by mass spectrometry. HADHA was identified as an LC3-interacting protein from primary IECs. The HADHA gene encodes the alpha subunit of the mitochondrial trifunctional protein. Given that HADHA catalyzes the last three steps of mitochondrial beta-oxidation of long-chain fatty acids, we investigated whether long-chain fatty acids induce autophagy in IECs. We found that palmitic acid induced autophagy in DLD-1, HT29, and HCT116 cells. HADHA was expressed in not only the mitochondria but also the cytosol. LC3 puncta co-localized with HADHA, which were enhanced by palmitic acid stimulation. However, LC3 puncta did not co-localize with Tom20, suggesting that HADHA was induced to associate with LC3 puncta at sites other than the mitochondria. Thus, HADHA may have extra-mitochondrial functions. Furthermore, we found that palmitic acid induced cell death in IECs, which was accelerated by bafilomycin A and chloroquine. These findings suggested that palmitic acid induced autophagy supports the survival of IECs. Taken together, these results suggested that HADHA is involved in long-chain fatty acid-induced autophagy in IECs, thus providing new insights into the pathology of IBD and revealing novel therapeutic targets of IBD. (C) 2017 Elsevier Inc. All rights reserved.