Llorián-Salvador María, Pérez-Martínez Daniel, Tang Miao, Duarri Anna, García-Ramirez Marta, Deàs-Just Anna, Álvarez-Guaita Anna, Ramos-Pérez Lorena, Bogdanov Patricia, Gomez-Sanchez Jose A, Stitt Alan W, Hernández Cristina, de la Fuente Alerie G, Simó Rafael
Universitat Autònoma de Barcelona, Barcelona, 08035, Spain.
Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain.
J Neuroinflammation. 2024 Dec 23;21(1):328. doi: 10.1186/s12974-024-03323-0.
The global incidence of type 2 diabetes (T2D) is rapidly increasing, with retinopathy being its most common complication and a leading cause of preventable blindness. Although the precise mechanisms involved in the development of diabetic retinopathy (DR) are not fully understood, defective immunomodulation is a recognized key factor in its pathophysiology. Regulatory T cells (Treg) regulate inflammation and promote regeneration, and while they are known to have important anti-inflammatory and neuroprotective roles in other tissues, including central nervous system, their role in the diabetic retina remains largely unknown. The aim of the present study is to examine the effect of Treg expansion of retinal neurodegeneration, an early event in the pathogenesis of DR.
Treg expansion was achieved by co-injecting recombinant mouse IL-2 with anti-IL-2 monoclonal antibody or its isotype in db/db mice as an established model of T2D. Treg expansion was confirmed via flow cytometry in blood, spleen, and retina. Fundus angiography was performed in the days prior to animal sacrifice at 18 weeks. To study the effect of Tregs on retinal neurons, glia and vascular permeability, immunohistochemistry against Cone-Arrestin, PKCα, synaptophysin, ChAT, TH, GFAP, Iba-1, calbindin, Brn3a, RBPMS, isolectin B4, and albumin was used. Retinal VEGF levels were measured with a magnetic bead-based immunoassay, and NLRP3, Casp1, p20 and IL-18 were analyzed by Western Blot in retinal homogenates.
There was a significant decrease in Treg in db/db mice blood. When this deficiency was corrected in db/db mice by systemic Treg expansion, there was an effective protection against retinal neurodegenerative, gliotic, inflammatory changes and vascular leakage associated with T2D. Importantly, Treg expansion did not impact the T2D phenotype in db/db mice as evaluated by blood glucose, HbA1c and circulating insulin.
Treg modulation in T2D offers a promising therapeutic approach to prevent early stages of DR. This strategy focuses on reducing neuroinflammation and mitigating the associated neuronal, glial, and vascular degenerative changes characteristic of DR.
2型糖尿病（T2D）的全球发病率正在迅速上升，视网膜病变是其最常见的并发症，也是可预防失明的主要原因。尽管糖尿病视网膜病变（DR）发生发展的确切机制尚未完全明确，但免疫调节缺陷是其病理生理学中公认的关键因素。调节性T细胞（Treg）可调节炎症并促进再生，虽然已知它们在包括中枢神经系统在内的其他组织中具有重要的抗炎和神经保护作用，但其在糖尿病视网膜中的作用仍 largely unknown。本研究的目的是研究Treg扩增对视网膜神经变性的影响，视网膜神经变性是DR发病机制中的早期事件。
在作为T2D既定模型的db/db小鼠中，通过将重组小鼠IL-2与抗IL-2单克隆抗体或其同型抗体共同注射来实现Treg扩增。通过流式细胞术在血液、脾脏和视网膜中确认Treg扩增。在动物18周处死前几天进行眼底血管造影。为了研究Tregs对视网膜神经元、神经胶质和血管通透性的影响，使用了针对视锥蛋白抑制蛋白、蛋白激酶Cα、突触素、胆碱乙酰转移酶、酪氨酸羟化酶、胶质纤维酸性蛋白、离子钙结合衔接分子1、钙结合蛋白、Brn3a、视网膜神经节细胞特异性RNA结合蛋白、异凝集素B4和白蛋白的免疫组织化学方法。用基于磁珠的免疫测定法测量视网膜血管内皮生长因子（VEGF）水平，并通过蛋白质免疫印迹法分析视网膜匀浆中的NLRP3、半胱天冬酶-1（Casp1）、p20和白细胞介素-18（IL-18）。
db/db小鼠血液中的Treg显著减少。当通过全身Treg扩增纠正db/db小鼠的这种缺陷时，可有效预防与T2D相关的视网膜神经变性、胶质增生、炎症变化和血管渗漏。重要的是，通过血糖、糖化血红蛋白（HbA1c）和循环胰岛素评估，Treg扩增并未影响db/db小鼠的T2D表型。
T2D中的Treg调节为预防DR的早期阶段提供了一种有前景的治疗方法。该策略侧重于减少神经炎症并减轻DR特有的相关神经元、神经胶质和血管退行性变化。
