Subretinal injection of amyloid-β peptide accelerates RPE cell senescence and retinal degeneration
Subretinal injection of amyloid-β peptide accelerates RPE cell senescence and retinal degeneration
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DOI：
10.3892/ijmm.2014.1993
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发表时间：
2015-01-01
影响因子：
5.4
通讯作者：
Xu, Ding
中科院分区：
文献类型：
--
作者：
Liu, Chaoqi;Cao, Lining;Xu, Ding
Drusen被认为是老年性黄斑变性（AMD）的标志特征。在我们之前的研究中，我们发现淀粉样蛋白- (A)肽（drusen的一种成分）诱导视网膜色素上皮细胞（RPE； RPE细胞）进入衰老；然而，其在体内的作用尚不清楚。因此，本研究旨在探讨A肽对C57BL/6小鼠RPE细胞衰老和衰老相关炎症的体内影响。C57BL/6小鼠视网膜下注射a（1-42）肽；注射后第7天，麻醉小鼠，用4%的多聚甲醛（PFA） PBS全身灌注，全眼去核。视网膜电图（ERG）评估视网膜功能，光镜和电镜检查视网膜形态学特征。采用激光共聚焦扫描眼底镜（cSLO）检测眼底自身荧光（FAF）。免疫荧光染色和western blot检测细胞衰老标志物p16（INK4a）的表达。RT-PCR检测rpe -脉络膜细胞因子的表达。在注射A（1-42）的小鼠中，暗位ERG反应下降。光镜下观察到退行性改变，包括内节段(IS)/外节段（OS）连接处的破坏，广泛的空泡化和布鲁氏膜（BrM）的厚度。在RPE中，液泡的积累和基础褶积的损失是用电子显微镜确定的。在A（1-42）注射小鼠中FAF和p16（INK4a）表达升高。此外，A（1-42）上调了rpe -脉络膜中白细胞介素(IL)-6和IL-8基因的表达。综上所述，我们的研究结果证实了A（1-42）肽对体内RPE衰老的影响。注射a的小鼠出现amd样眼部病理。因此，RPE细胞衰老是炎症和视网膜变性之间的潜在机制联系。
Drusen are considered a hallmark characteristic of age-related macular degeneration (AMD). In our previous study, we found that amyloid- (A) peptide, a component of drusen, induced the cells of the retinal pigment epithelium (RPE; RPE cells) to enter senescence; however, its effects in vivo remain unknown. Thus, the present study was carried out to explore the in vivo effects of A peptide on RPE cell senescence and senescence-associated inflammation in C57BL/6 mice. C57BL/6 mice received a subretinal injection of A(1-42) peptide; on day 7 post-injection, the mice were anesthetized and subjected to whole-body perfusion with 4% paraformaldehyde (PFA) in PBS and the whole eyes were then enucleated. Retinal function was assessed by electroretinography (ERG), and the morphological characteristics of the retina were examined by light and electron microscopy. Fundus autofluorescence (FAF) was examined by confocal scanning laser ophthalmoscopy (cSLO). The expression of p16(INK4a), a marker of cellular senescence, was examined by immunofluorescence staining and western blot analysis. The RPE-choroid was analyzed for cytokine expression by RT-PCR. In A(1-42)-injected mice, scotopic ERG responses declined. Degenerative alterations, including the disruption of the inner segment (IS)/outer segment (OS) junction and extensive vacuolation and thickness of Bruch's membrane (BrM) were observed under a a light microscope. The accumulation of vacuoles and the loss of basal infoldings in the RPE were identified using an electron microscope. FAF and p16(INK4a) expression increased in A(1-42)-injected mice. In addition, A(1-42) upregulated interleukin (IL)-6 and IL-8 gene expression in the RPE-choroid. In conclusion, our results confirm the effects of A(1-42) peptide on RPE senescence in vivo. The A-injected mice developed AMD-like ocular pathology. It is thus suggested that RPE cell senescence is a potential mechanistic link between inflammation and retinal degeneration.