TP53 status regulates ACSL5-induced expression of mitochondrial mortalin in enterocytes and colorectal adenocarcinomas
TP53 status regulates ACSL5-induced expression of mitochondrial mortalin in enterocytes and colorectal adenocarcinomas
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DOI：
10.1007/s00441-014-1826-8
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发表时间：
2014-07-01
影响因子：
3.6
通讯作者：
Gassler, Nikolaus
中科院分区：
文献类型：
--
作者：
Klaus, Christina;Kaemmerer, Elke;Gassler, Nikolaus
酰基辅酶a合成酶5 （ACSL5）是一种线粒体定位酶，催化长链脂肪酸硫酯的合成，并在生理上参与肠细胞的促凋亡感知。本研究的目的是确定acsl5依赖性线粒体表达蛋白的调控以及正常和患病人肠粘膜相关途径的表征。对ACSL5转染体和cco2对照体分离的线粒体进行蛋白质组学分析。通过定量反转录加聚合酶链反应、Western blotting、短干扰rna介导的基因沉默和其他细胞培养实验验证acsl5依赖性蛋白的合成。脂质变化用串联质谱法分析。acsl5相关通路在人肠正常粘膜和散发性腺癌中均有表现。在转染ACSL5的CaCo2细胞中，线粒体中的死亡蛋白（HSPA9）增加了约两倍，而细胞质中的死亡蛋白水平不变。ACSL5过表达引起的酰基辅酶a /鞘脂代谢紊乱是至关重要的。在HEK293和Lovo（野生型TP53[肿瘤蛋白p53]）和CaCo2 （p53阴性，TP53突变）细胞中发现了acsl5相关的线粒体mortalin过表达，而在col320dm细胞（突变的TP53）中没有发现。在正常人肠黏膜中，ACSL5和mortalin从下向上呈梯度升高，而p53（野生型TP53）呈下降趋势。在具有强p53免疫染色的散发性肠腺癌（突变TP53）中，acsl5相关的死亡蛋白表达是异质性的。acsl5诱导的线粒体mortalin表达被认为是对acsl5相关脂质代谢变化的应激反应，并受TP53状态的调节。突变的TP53使ACSL5和线粒体死亡蛋白解耦可能在结直肠癌发生中起重要作用。
Acyl-CoA synthetase 5 (ACSL5), a mitochondrially localized enzyme, catalyzes the synthesis of long-chain fatty acid thioesters and is physiologically involved in pro-apoptotic sensing of enterocytes. The aim of the present study is to identify an ACSL5-dependent regulation of mitochondrially expressed proteins and the characterization of related pathways in normal and diseased human intestinal mucosa. Proteomics of isolated mitochondria from ACSL5 transfectants and CaCo2 controls were performed. ACSL5-dependent protein synthesis was verified with quantitative reverse transcription plus the polymerase chain reaction, Western blotting, short-interfering-RNA-mediated gene silencing and additional cell culture experiments. Lipid changes were analyzed with tandem mass spectrometry. ACSL5-related pathways were characterized in normal mucosa and sporadic adenocarcinomas of the human intestine. In CaCo2 cells transfected with ACSL5, mortalin (HSPA9) was about two-fold increased in mitochondria, whereas cytoplasmic mortalin levels were unchanged. Disturbance of acyl-CoA/sphingolipid metabolism, induced by ACSL5 over-expression, was characterized as crucial. ACSL5-related over-expression of mitochondrial mortalin was found in HEK293 and Lovo (wild-type TP53 [tumor protein p53]) and CaCo2 (p53-negative; TP53 mutated) cells but not in Colo320DM cells (mutated TP53). In normal human intestinal mucosa, an increasing gradient of both ACSL5 and mortalin from bottom to top was observed, whereas p53 (wild-type TP53) decreased. In sporadic intestinal adenocarcinomas with strong p53 immunostaining (mutated TP53), ACSL5-related mortalin expression was heterogeneous. ACSL5-induced mitochondrial mortalin expression is assumed to be a stress response to ACSL5-related changes in lipid metabolism and is regulated by the TP53 status. Uncoupling of ACSL5 and mitochondrial mortalin by mutated TP53 could be important in colorectal carcinogenesis.