Palmitate-induced activation of mitochondrial metabolism promotes oxidative stress and apoptosis in H4IIEC3 rat hepatocytes.
Palmitate-induced activation of mitochondrial metabolism promotes oxidative stress and apoptosis in H4IIEC3 rat hepatocytes.
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棕榈酸盐诱导的线粒体代谢的激活促进了H4IIEC3大鼠肝细胞的氧化应激和凋亡。
DOI：
10.1016/j.metabol.2013.10.009
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发表时间：
2014-02
影响因子：
9.8
通讯作者：
Young, Jamey D.
中科院分区：
文献类型：
--
作者：
Egnatchik, Robert A.;Leamy, Alexandra K.;Noguchi, Yasushi;Shiota, Masakazu;Young, Jamey D.
肝脂毒性的特征是活性氧（ROS）积累，线粒体功能障碍和过度凋亡，但导致氧化损伤和细胞死亡的生化事件的确切顺序仍不清楚。本研究的目的是描述线粒体代谢在介导肝细胞脂毒性中的作用。我们用游离脂肪酸与抗氧化剂和线粒体抑制剂联合治疗H4 IIEC 3大鼠肝癌细胞，旨在阻断细胞凋亡进程中的关键事件。然后，我们应用13 C代谢通量分析（MFA）来量化与这些治疗相关的线粒体途径改变。单独棕榈酸酯治疗导致氧摄取率和大多数线粒体通量加倍。用抗氧化剂N-乙酰半胱氨酸（NAC）补充培养基减少了ROS积累和半胱天冬酶激活，并部分恢复了细胞活力。然而，13 C MFA显示，用NAC处理并没有使棕榈酸诱导的代谢改变正常化，表明ROS升高和下游凋亡事件都没有促成线粒体活化。为了直接限制线粒体代谢，向用棕榈酸酯处理的细胞中加入复合物I抑制剂苯丙氨酸。此外，苯丙氨酸消除异常的ROS积累，防止出现凋亡标志物，并正常化线粒体碳流。进一步的研究表明，谷氨酰胺在棕榈酸盐的存在下，而不是脂肪酸β-氧化的情况下，为线粒体代谢的升高提供了主要燃料，并且谷氨酰胺的消耗可以通过与苯丙氨酸而不是NAC共处理来减少。我们的结果表明，棕榈酸处理的H4 IIEC 3细胞中的活性氧积累发生在线粒体氧化代谢改变的下游，这与β氧化无关，并且发生在细胞凋亡启动之前。
Hepatic lipotoxicity is characterized by reactive oxygen species (ROS) accumulation, mitochondrial dysfunction, and excessive apoptosis, but the precise sequence of biochemical events leading to oxidative damage and cell death remain unclear. The goal of this study was to delineate the role of mitochondrial metabolism in mediating hepatocyte lipotoxicity. We treated H4IIEC3 rat hepatoma cells with free fatty acids in combination with antioxidants and mitochondrial inhibitors designed to block key events in the progression toward apoptosis. We then applied 13C metabolic flux analysis (MFA) to quantify mitochondrial pathway alterations associated with these treatments. Treatment with palmitate alone led to a doubling in oxygen uptake rate and in most mitochondrial fluxes. Supplementing culture media with the antioxidant N-acetyl-cysteine (NAC) reduced ROS accumulation and caspase activation and partially restored cell viability. However, 13C MFA revealed that treatment with NAC did not normalize palmitate-induced metabolic alterations, indicating that neither elevated ROS nor downstream apoptotic events contributed to mitochondrial activation. To directly limit mitochondrial metabolism, the complex I inhibitor phenformin was added to cells treated with palmitate. Phenformin addition eliminated abnormal ROS accumulation, prevented the appearance of apoptotic markers, and normalized mitochondrial carbon flow. Further studies revealed that glutamine provided the primary fuel for elevated mitochondrial metabolism in the presence of palmitate, rather than fatty acid beta-oxidation, and that glutamine consumption could be reduced through co-treatment with phenformin but not NAC. Our results indicate that ROS accumulation in palmitate-treated H4IIEC3 cells occurs downstream of altered mitochondrial oxidative metabolism, which is independent of beta-oxidation and precedes apoptosis initiation.
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DOI：
10.1056/nejmoa0907929
发表时间：
2010-05-06
期刊：
The New England journal of medicine
影响因子：
--
作者：
Sanyal AJ;Chalasani N;Kowdley KV;McCullough A;Diehl AM;Bass NM;Neuschwander-Tetri BA;Lavine JE;Tonascia J;Unalp A;Van Natta M;Clark J;Brunt EM;Kleiner DE;Hoofnagle JH;Robuck PR;NASH CRN
通讯作者：
NASH CRN
DOI：
10.1152/ajpheart.00726.2001
发表时间：
2002-02-01
影响因子：
4.8
作者：
Hickson-Bick, DLM;Sparagna, GC;McMillin, JB
通讯作者：
McMillin, JB
影响因子：
4.8
作者：
Listenberger, LL;Ory, DS;Schaffer, JE
通讯作者：
Schaffer, JE
影响因子：
6.5
作者：
Satapati, Santhosh;Sunny, Nishanth E.;Burgess, Shawn C.
通讯作者：
Burgess, Shawn C.
DOI：
10.1074/jbc.m901488200
发表时间：
2009-05-29
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Nakamura S;Takamura T;Matsuzawa-Nagata N;Takayama H;Misu H;Noda H;Nabemoto S;Kurita S;Ota T;Ando H;Miyamoto K;Kaneko S
通讯作者：
Kaneko S