Nmnat 1: a Security Guard of Retinal Ganglion Cells (RGCs) in Response to High Glucose Stress
Nmnat 1: a Security Guard of Retinal Ganglion Cells (RGCs) in Response to High Glucose Stress
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DOI：
10.1159/000445576
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发表时间：
2016-05
影响因子：
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通讯作者：
Rong-mei Zhou;Yiyang Shen;Jin Yao;Hong Yang;Kun Shan;Xiu-Miao Li;Qin Jiang;B. Yan
中科院分区：
文献类型：
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作者：
Rong-mei Zhou;Yiyang Shen;Jin Yao;Hong Yang;Kun Shan;Xiu-Miao Li;Qin Jiang;B. Yan
背景/目的：视网膜神经变性是糖尿病视网膜病变（DR）病理过程的早期事件。视网膜神经节细胞（RGC）损伤是神经退行性过程中的重要病理特征。保护 RGC 免受高糖诱导的损伤是延缓或阻止糖尿病相关视网膜神经病变的一种有前景的策略。本研究旨在探讨 Nmnat1（一种催化烟酰胺腺嘌呤二核苷酸 (NAD) 生物合成关键步骤的酶）在高糖诱导的 RGC 损伤中的作用。方法：采用Western blot和免疫荧光分析检测Nmnat1在视网膜和RGC-5细胞中的表达模式。进行MTT测定、Hoechst染色、台盼蓝染色和钙黄绿素-AM/碘化丙啶(PI)染色以确定Nmnat1敲低对RGC-5细胞功能的影响。进行微阵列和生物信息学分析，以确定受 Nmnat1 敲低影响的潜在信号通路。通过药理干预、分子干预和体外实验揭示Nmnat1介导的RGC-5细胞功能保护作用的分子机制。结果：Nmnat1 在视网膜和 RGC-5 细胞中组成型表达。 Nmnat1 敲低会加重 RGC 损伤，并加速高糖应激下 RGC-5 细胞凋亡的发展。 MAPK 信号传导是受 Nmnat1 敲低影响的主要信号传导途径。在高葡萄糖应激下，Nmnat1 敲低会导致 p38-MAPK 信号失活。 p38-MAPK 通路抑制剂强烈阻断 Nmnat1 介导的对 RGC-5 细胞功能的保护作用。结论：Nmnat1通过p38-MAPK信号通路保护RGC免受高糖诱导的损伤。 Nmnat1 可能作为糖尿病相关视网膜神经病变的神经保护靶点。
Background/Aims: Retinal neurodegeneration is an early event in the pathological process of diabetic retinopathy (DR). Retinal ganglion cell (RGC) injury is an important pathological feature during neurodegenerative process. Protecting RGCs from high glucose-induced injury is a promising strategy for delaying or hindering diabetes mellitus-related retinal neuropathy. This study aims to investigate the role of Nmnat1, an enzyme which catalyzes a key step in the biosynthesis of nicotinamide adenine dinucleotide (NAD), in high glucose-induced RGC injury. Methods: Western blot and immunofluorescence analysis was conducted to detect Nmnat1 expression pattern in the retina and RGC-5 cell. MTT assay, Hoechst staining, trypan blue staining, and calcein-AM/ propidium iodide (PI) staining was conducted to determine the effect of Nmnat1 knockdown on RGC-5 cell function. Microarray and bioinformatics analysis was conducted to identify potential signaling pathways affected by Nmnat1 knockdown. Pharmacological intervention, molecular intervention, and in vitro experiments were conducted to reveal molecular mechanism of Nmnat1-mediated protective effect on RGC-5 cell function. Results: Nmnat1 is constitutively expressed in retina and RGC-5 cells. Nmnat1 knockdown aggravates RGC injury, and accelerates the development of RGC-5 cell apoptosis upon high glucose stress. MAPK signaling is the primary signaling pathway affected by Nmnat1 knockdown. Under high glucose stress, Nmnat1 knockdown leads to p38-MAPK signaling inactivation. p38-MAPK pathway inhibitor strongly blocks Nmnat1-mediated protective effect on RGC-5 cell function. Conclusion: Nmnat1 protects RGC against high glucose-induced injury via p38-MAPK signaling pathway. Nmnat1 may serve as a neuroprotective target for diabetes mellitus-related retinal neuropathy.