Cell Isolation and Transplantation Center, Diabetes Center, University of Geneva Hospitals, Geneva, Switzerland.
Department of Pathology and Immunology, University of Geneva, 1211, Geneva 4, Geneva, Switzerland.
Sci Rep. 2019 Dec 18;9(1):19350. doi: 10.1038/s41598-019-55521-z.
TLR4 is a transmembrane receptor of the innate immune system that recognizes LPS from gram-negative bacteria. Its stimulation induces pro-inflammatory responses and modulates adaptive immunity. Our aim is to determine the role of TLR4 in the activation and proliferation of T lymphocytes in the onset of autoimmune diabetes, using the non-obese diabetic (NOD) mouse model. Antigen-specific activation and proliferation of diabetogenic T cells were assessed in vitro by Carboxyfluorescein succinimidyl ester (CFSE) dilution, in presence of vehicle or CLI-095, a cyclohexene derivative that inhibits TLR4 signaling. NOD mice were treated with vehicle or CLI-095 and sacrificed either before or after the onset of autoimmune diabetes. T lymphocyte activation and proliferation were evaluated in treated and control mice. Insulitis was analyzed by histology and diabetes incidence was determined in treated and control mice. Our results demonstrate that TLR4 blockade decreases CD4+ T lymphocyte activation and auto-antigen-specific proliferation both in vitro and in vivo, decreases the infiltrative insulitis and finally prevents the onset of spontaneous diabetes. Taken together, our data demonstrate that TLR4 signaling contributes to the development and maintenance of autoimmune diabetes. The immunomodulatory effect of CLI-095 could be part of a preventive strategy targeting patients at risk for type 1 diabetes.
TLR4 是先天免疫系统的跨膜受体，可识别革兰氏阴性菌的 LPS。其刺激可诱导促炎反应并调节适应性免疫。我们的目的是使用非肥胖型糖尿病（NOD）小鼠模型，确定 TLR4 在自身免疫性糖尿病发病过程中对 T 淋巴细胞的激活和增殖中的作用。通过 Carboxyfluorescein succinimidyl ester（CFSE）稀释，在载体或 CLI-095 存在下，评估体外抗原特异性活化和增殖的致糖尿病 T 细胞，CLI-095 是一种抑制 TLR4 信号的环己烯衍生物。用载体或 CLI-095 处理 NOD 小鼠，并在自身免疫性糖尿病发病前或发病后处死。在治疗和对照小鼠中评估 T 淋巴细胞的激活和增殖。通过组织学分析胰岛炎，并确定治疗和对照小鼠中的糖尿病发生率。我们的结果表明，TLR4 阻断可减少体外和体内 CD4+T 淋巴细胞的活化和自身抗原特异性增殖，减少浸润性胰岛炎，并最终预防自发性糖尿病的发生。综上所述，我们的数据表明 TLR4 信号通路参与了自身免疫性糖尿病的发生和维持。CLI-095 的免疫调节作用可能是针对 1 型糖尿病高危患者的预防策略的一部分。
