Sekar Ponarulselvam, Hsiao George, Chen Yuan-Shen, Lin Wan-Wan, Chan Chi-Ming
Graduate Institute of Medical Sciences, Taipei Medical University, Taipei 110301, Taiwan.
Department of Pharmacology, College of Medicine, National Taiwan University, Taipei 100233, Taiwan.
Antioxidants (Basel). 2023 Jan 6;12(1):141. doi: 10.3390/antiox12010141.
Adenosine triphosphate (ATP) released from dying cells with high concentrations is sensed as a danger signal by the P2X7 receptor. Sodium iodate (NaIO) is an oxidative toxic agent, and its retinal toxicity has been used as the model of dry age-related macular degeneration (AMD). In this study, we used NaIO-treated mice and cultured retinal cells, including BV-2 microglia, 661W photoreceptors, rMC1 Müller cells and ARPE-19 retinal epithelial cells, to understand the pathological action of P2X7 in retinal degeneration. We found that NaIO can significantly decrease the photoreceptor function by reducing a-wave and b-wave amplitudes in electroretinogram (ERG) analysis. Optical coherence tomography (OCT) analysis revealed the degeneration of retinal epithelium and ganglion cell layers. Interestingly, P2X7 mice were protected from the NaIO-induced retinopathy and inflammatory NLRP3, IL-1β and IL-6 gene expression in the retina. Hematoxylin and eosin staining indicated that the retinal epithelium was less deteriorated in P2X7 mice compared to the WT group. Although P2X7 was barely detected in 661W, rMC1 and ARPE-19 cells, its gene and protein levels can be increased after NaIO treatment, leading to a synergistic cytotoxicity of BzATP [2'(3')-O-(4-benzoylbenzoyl)adenosine-5'-triphosphate tri(triethyleneammonium)salt] and NaIO administration in ARPE-19 cells. In conclusion, the paracrine action of the ATP/P2X7 axis via cell-cell communication is involved in NaIO-induced retinal injury. Our results show that P2X7 antagonist might be a potential therapy in inflammation-related retinal degeneration.
高浓度的三磷酸腺苷（ATP）从濒死细胞中释放出来，被P2X7受体感知为一种危险信号。碘酸钠（NaIO）是一种氧化毒性剂，其视网膜毒性已被用作干性年龄相关性黄斑变性（AMD）的模型。在本研究中，我们使用NaIO处理的小鼠和培养的视网膜细胞，包括BV-2小胶质细胞、661W光感受器、rMC1 Müller细胞和ARPE-19视网膜上皮细胞，以了解P2X7在视网膜变性中的病理作用。我们发现，NaIO可通过降低视网膜电图（ERG）分析中的a波和b波振幅，显著降低光感受器功能。光学相干断层扫描（OCT）分析显示视网膜上皮和神经节细胞层发生变性。有趣的是，P2X7基因敲除小鼠可免受NaIO诱导的视网膜病变以及视网膜中炎症相关NLRP3、IL-1β和IL-6基因表达的影响。苏木精和伊红染色表明，与野生型组相比，P2X7基因敲除小鼠的视网膜上皮损伤较轻。虽然在661W、rMC1和ARPE-19细胞中几乎检测不到P2X7，但其基因和蛋白水平在NaIO处理后可升高，导致BzATP[2'（3'）-O-（4-苯甲酰苯甲酰基）腺苷-5'-三磷酸三（三乙铵）盐]和NaIO联合给药对ARPE-19细胞产生协同细胞毒性。总之，ATP/P2X7轴通过细胞间通讯的旁分泌作用参与了NaIO诱导的视网膜损伤。我们的结果表明，P2X7拮抗剂可能是炎症相关视网膜变性的一种潜在治疗方法。
