Mitochondrial Ceramide Effects on the Retinal Pigment Epithelium in Diabetes
Mitochondrial Ceramide Effects on the Retinal Pigment Epithelium in Diabetes
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DOI：
10.3390/ijms21113830
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发表时间：
2020-06-01
影响因子：
5.6
通讯作者：
Proshlyakov, Denis A.
中科院分区：
文献类型：
--
作者：
Levitsky, Yan;Hammer, Sandra S.;Proshlyakov, Denis A.
已知包括内部（视网膜内皮细胞）和外部（视网膜色素上皮（RPE））血-视网膜屏障（BRB）的细胞中的线粒体损伤先于初始BRB破坏和糖尿病视网膜病变（DR）中的进一步组织病理学异常。我们以前证明，激活酸性鞘磷脂酶（ASM）是一个重要的早期事件的发病机制，DR，最近的研究表明，神经酰胺和线粒体功能之间有一个错综复杂的连接。本研究旨在确定ASM依赖的线粒体神经酰胺积累在糖尿病诱导的RPE细胞损伤中的作用。从链脲佐菌素（STZ）诱导的糖尿病大鼠视网膜（持续7周）分离的线粒体显示，与对照组相比，神经酰胺与鞘磷脂的比例增加了1.64 +/- 0.29倍。相反，与野生型同窝仔相比，从ASM敲除小鼠视网膜分离的线粒体中神经酰胺与鞘磷脂的比例降低，证实了ASM在线粒体神经酰胺产生中的作用。与对照供体相比，来自糖尿病供体的RPE细胞中细胞神经酰胺升高2.67 +/- 1.07倍，这些变化与IL-1 β、IL-6和ASM的基因表达增加相关。用高糖处理来自对照供体的RPE细胞导致ASM、血管内皮生长因子（VEGF）和细胞间粘附分子1（ICAM-1）mRNA升高。来自糖尿病供体的RPE显示线粒体片段化和2.68 +/-0.66倍的呼吸控制率（RCR）降低。用高糖处理永生化细胞视觉研究（ARPE-19）细胞导致柠檬酸合酶活性在72小时时降低25% +/-1.6%。抑制ASM与地昔帕明（15 μ M，每天1小时）取消了代谢功能参数的下降。我们的研究结果与糖尿病诱导的线粒体神经酰胺增加通过ASM依赖性途径导致视网膜RPE细胞线粒体功能受损一致。
Mitochondrial damage in the cells comprising inner (retinal endothelial cells) and outer (retinal pigment epithelium (RPE)) blood-retinal barriers (BRB) is known to precede the initial BRB breakdown and further histopathological abnormalities in diabetic retinopathy (DR). We previously demonstrated that activation of acid sphingomyelinase (ASM) is an important early event in the pathogenesis of DR, and recent studies have demonstrated that there is an intricate connection between ceramide and mitochondrial function. This study aimed to determine the role of ASM-dependent mitochondrial ceramide accumulation in diabetes-induced RPE cell damage. Mitochondria isolated from streptozotocin (STZ)-induced diabetic rat retinas (7 weeks duration) showed a 1.64 +/- 0.29-fold increase in the ceramide-to-sphingomyelin ratio compared to controls. Conversely, the ceramide-to-sphingomyelin ratio was decreased in the mitochondria isolated from ASM-knockout mouse retinas compared to wild-type littermates, confirming the role of ASM in mitochondrial ceramide production. Cellular ceramide was elevated 2.67 +/- 1.07-fold in RPE cells derived from diabetic donors compared to control donors, and these changes correlated with increased gene expression of IL-1 beta, IL-6, and ASM. Treatment of RPE cells derived from control donors with high glucose resulted in elevated ASM, vascular endothelial growth factor (VEGF), and intercellular adhesion molecule 1 (ICAM-1) mRNA. RPE from diabetic donors showed fragmented mitochondria and a 2.68 +/- 0.66-fold decreased respiratory control ratio (RCR). Treatment of immortalized cell in vision research (ARPE-19) cells with high glucose resulted in a 25% +/- 1.6% decrease in citrate synthase activity at 72 h. Inhibition of ASM with desipramine (15 mu M, 1 h daily) abolished the decreases in metabolic functional parameters. Our results are consistent with diabetes-induced increase in mitochondrial ceramide through an ASM-dependent pathway leading to impaired mitochondrial function in the RPE cells of the retina.