New Insights into the Mechanisms of Action of Topical Administration of GLP-1 in an Experimental Model of Diabetic Retinopathy
New Insights into the Mechanisms of Action of Topical Administration of GLP-1 in an Experimental Model of Diabetic Retinopathy
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DOI：
10.3390/jcm8030339
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发表时间：
2019-03-11
影响因子：
3.9
通讯作者：
Hernandez, Cristina
中科院分区：
文献类型：
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作者：
Sampedro, Joel;Bogdanov, Patricia;Hernandez, Cristina
本研究的主要目的是评估局部应用胰高血糖素样肽-1(GLP-1)能否逆转长期糖尿病(24周)引起的糖尿病小鼠神经血管单位的损害，并探讨其潜在的机制。为此，db/db小鼠被给予GLP-1滴眼液或赋形剂治疗3周。另外，以db/+小鼠作为对照。在体内进行的研究包括视网膜电图仪和使用埃文斯蓝评估血管渗漏。免疫荧光法检测NF-kappaB、GFAP和Ki67蛋白的表达。WB法检测caspase9、AMPK、IKBα、NF-kappaB、AKT、GSK3、β-catenin、Bclxl、VEGF的表达。逆转录-聚合酶链式反应和免疫荧光法检测血管内皮生长因子、IL-1β、IL-6、肿瘤坏死因子-α、IL-18和NLRP3的表达。我们发现，局部应用GLP-1可以逆转反应性胶质增生和白蛋白外溢，并保护细胞免受细胞凋亡和视网膜功能障碍的影响。关于相关机制，GLP-1通过减少核因子-kappaB、炎症体和促炎因子发挥抗炎作用。此外，还可降低血管内皮细胞生长因子的表达。此外，GLP-1通过增加抗凋亡蛋白Bclxl和信号通路Akt/GSK3b/β-catenin促进细胞存活。Ki67结果显示，GLP-1处理可诱导神经再生。总之，局部应用GLP-1通过调节参与糖尿病视网膜病变(DR)发展的基本途径，逆转了神经血管单位的损害。这些对神经血管单位的有益影响可能为临床试验铺平道路，以证实GLP-1在DR早期的有效性。
The main goals of this work were to assess whether the topical administration of glucagon-like peptide-1 (GLP-1) could revert the impairment of the neurovascular unit induced by long-term diabetes (24 weeks) in diabetic mice and to look into the underlying mechanisms. For that reason, db/db mice were treated with eye drops of GLP-1 or vehicle for 3 weeks. Moreover, db/+ mice were used as control. Studies performed in vivo included electroretinogramand the assessment of vascular leakage by using Evans Blue. NF-kappa B, GFAP and Ki67 proteins were analyzed by immunofluorescence (IF). Additionally, caspase 9, AMPK, IKB alpha, NF-kappa B, AKT, GSK3, beta-catenin, Bcl-xl, and VEGF were analyzed by WB. Finally, VEGF, IL-1 beta, IL-6, TNF-alpha, IL-18, and NLRP3 were studied by reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescence. We found that topical administration of GLP-1 reverted reactive gliosis and albumin extravasation, and protected against apoptosis and retinal dysfunction. Regarding the involved mechanisms, GLP-1 exerted an anti-inflammatory action by decreasing NF-kappa B, inflammosome, and pro-inflammatory factors. In addition, it also decreased VEGF expression. Furthermore, GLP-1 promoted cell survival by increasing the anti-apoptotic protein Bcl-xl and the signaling pathway Akt/GSK3b/beta-catenin. Finally, Ki67 results revealed that GLP-1 treatment could induce neurogenesis. In conclusion, the topical administration of GLP-1 reverts the impairment of the neurovascular unit by modulating essential pathways involved in the development of diabetic retinopathy (DR). These beneficial effects on the neurovascular unit could pave the way for clinical trials addressed to confirm the effectiveness of GLP-1 in early stages of DR.