Hyperglycemia magnifies Schwann cell dysfunction and cell death triggered by PA-induced lipotoxicity

被引:74
作者
Padilla, Amelia [1 ,2 ,3 ]
Descorbeth, Magda [1 ]
Almeyda, Audra L. [1 ]
Payne, Kimberly [1 ,2 ,3 ]
De Leon, Marino [1 ,2 ,3 ]
机构
[1] Loma Linda Univ, Sch Med, Ctr Hlth Dispar & Mol Med, Loma Linda, CA 92350 USA
[2] Loma Linda Univ, Sch Med, Dept Basic Sci, Loma Linda, CA 92350 USA
[3] Loma Linda Univ, Sch Med, Dept Pathol & Human Anat, Loma Linda, CA 92350 USA
关键词
Lipotoxicity; Schwann cells; Peripheral neuropathy; ER stress; Type; 2; diabetes; ENDOPLASMIC-RETICULUM STRESS; ACID-INDUCED APOPTOSIS; FREE FATTY-ACIDS; OXIDATIVE STRESS; HIGH GLUCOSE; DIABETIC-NEUROPATHY; PHYSICAL-PROPERTIES; LIPID-ACCUMULATION; NERVOUS-SYSTEM; PALMITIC ACID;
D O I
10.1016/j.brainres.2010.11.013
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
Lipid overload resulting in lipotoxicity is prominent in a number of chronic diseases and has been associated with cellular dysfunction and cell death. This study characterizes palmitic acid-induced lipotoxicity (PA-LTx) in Schwann cell cultures grown in normal and high glucose concentrations. The study shows for the first time that Schwann cell (SC) cultures exposed to elevated levels of PA exhibit a dose- and time-dependent loss in cell viability. Hoescht and Annexin V/7AAD staining confirmed cell death through apoptosis and the lipotoxic effect was more dramatic in SC cultures grown under high glucose conditions. The first indication of cellular dysfunction in treated SC cultures was a decrease in Ca++ levels in the endoplasmic reticulum (ER, [Ca++](ER)) observed five minutes following the initial challenge with PA. This decrease in [Ca++](ER) was followed by a significant increase in the expression of ER stress signature genes CHOP, Xbp1 and GRP78. The early ER stress response induced by PA-LTx was followed by a strong mitochondrial membrane depolarization. Flow cytometry using 2', 7'-dichlorodihydrofluorescein diacetate (H(2)DCFDA) showed an increase in oxidative stress within three to six hours after PA treatment. Treatment of cultures undergoing PA-LTx with the calcium chelator BAPTA-AM and the anti-oxidant MCI-186 significantly reversed the lipotoxic effect by decreasing the generation of ROS and significantly increasing cell viability. We conclude that lipotoxicity in Schwann cells results in cellular dysfunction and cell death that involves a robust ER stress response, mitochondrial dysfunction and an augmented state of cellular oxidative stress (ASCOS). (C) 2010 Elsevier B.V. All rights reserved.
引用
收藏
页码:64 / 79
页数:16
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