Disruption of Fractalkine Signaling Leads to Microglial Activation and Neuronal Damage in the Diabetic Retina.
Disruption of Fractalkine Signaling Leads to Microglial Activation and Neuronal Damage in the Diabetic Retina.
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DOI：
10.1177/1759091415608204
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发表时间：
2015-09
期刊：
影响因子：
4.7
通讯作者：
Cardona AE
中科院分区：
文献类型：
--
作者：
Cardona SM;Mendiola AS;Yang YC;Adkins SL;Torres V;Cardona AE
Fractalkine（CX 3CL 1或FKN）是一种在神经元膜上表达的膜结合趋化因子，并被蛋白水解切割以脱落可溶性化学引诱物结构域。FKN通过其在小胶质细胞和其他外周白细胞上表达的独特受体CX 3CR 1发出信号。本研究的目的是使用糖尿病视网膜病变模型确定CX 3CR 1在炎症介导的视网膜神经元损伤中的作用。为此，我们比较了非糖尿病和糖尿病（Ins 2Akita）CX 3CR 1野生型和CX 3CR 1缺陷小鼠在10和20周龄时的神经元，小胶质细胞和星形胶质细胞密度和炎症反应。我们的研究结果表明，Ins 2秋田CX 3 CR 1基因敲除小鼠表现出（a）视网膜神经节细胞层中神经元细胞计数减少，（B）小胶质细胞数量增加，（c）星形胶质细胞反应减少，与20周龄时的Ins 2秋田CX 3 CR 1野生型小鼠相当。使用PCR阵列的炎症反应分析显示，糖尿病组织中的几个炎症基因差异调节。其中，Ins 2 Akita CX 3CR 1缺陷小鼠在10周龄时的反应显示，IL-1β在转录水平上显著上调，这在可溶性视网膜提取物中通过酶联免疫吸附测定得到证实。总体而言，IL-1β、VEGF和亚硝酸盐水平作为一氧化氮产生的读数在Ins 2秋田CX 3CR 1缺陷型视网膜中丰富。值得注意的是，双重免疫荧光染色显示星形胶质细胞在Ins 2秋田视网膜中充当IL-1β的来源，并且CX 3CR 1缺陷型小胶质细胞通过IL-1β释放增强炎症反应。总的来说，这些数据表明，在CX 3CR 1的情况下，失调的小胶质细胞反应有助于炎症介导的糖尿病视网膜神经元损伤。
Fractalkine (CX3CL1 or FKN) is a membrane-bound chemokine expressed on neuronal membranes and is proteolytically cleaved to shed a soluble chemoattractant domain. FKN signals via its unique receptor CX3CR1 expressed on microglia and other peripheral leukocytes. The aim of this study is to determine the role of CX3CR1 in inflammatory-mediated damage to retinal neurons using a model of diabetic retinopathy. For this, we compared neuronal, microglial, and astroglial densities and inflammatory response in nondiabetic and diabetic (Ins2Akita) CX3CR1-wild-type and CX3CR1-deficient mice at 10 and 20 weeks of age. Our results show that Ins2Akita CX3CR1-knockout mice exhibited (a) decreased neuronal cell counts in the retinal ganglion cell layer, (b) increased microglial cell numbers, and (c) decreased astrocyte responses comparable with Ins2Akita CX3CR1-Wild-type mice at 20 weeks of age. Analyses of the inflammatory response using PCR arrays showed several inflammatory genes differentially regulated in diabetic tissues. From those, the response in Ins2Akita CX3CR1-deficient mice at 10 weeks of age revealed a significant upregulation of IL-1β at the transcript level that was confirmed by enzyme-linked immunosorbent assay in soluble retinal extracts. Overall, IL-1β, VEGF, and nitrite levels as a read out of nitric oxide production were abundant in Ins2Akita CX3CR1-deficient retina. Notably, double immunofluorescence staining shows that astrocytes act as a source of IL-1β in the Ins2Akita retina, and CX3CR1-deficient microglia potentiate the inflammatory response via IL-1β release. Collectively, these data demonstrate that dysregulated microglial responses in absence of CX3CR1 contribute to inflammatory-mediated damage of neurons in the diabetic retina.