The nuclear receptors RORα and RORγt (retinoic acid receptor-related orphan receptors α and γt) are essential for the development of TH17 cells, the T-helper cells that produce interleukin-17. Two groups report the identification of RORγt inhibitors, compounds that could have potential in the treatment of autoimmune diseases. Huh et al. used a chemical screen in an insect-cell-based reporter system to identify the cardiac glycoside digoxin and various derivatives as inhibitors of the transcriptional activity of RORγt. Through this mechanism, these compounds block the differentiation of TH17 cells in mice, and inhibit interleukin-17 production in vitro in human T cells. Solt et al. describe a synthetic ligand, named SR1001, that functions as an inverse agonist for RORα and RORγt, and show that it blocks TH17 development in vitro and inhibits experimental encephalomyelitis in mice. T-helper cells that produce interleukin-17 (TH17 cells) are a recently identified CD4+ T-cell subset with characterized pathological roles in autoimmune diseases1,2,3. The nuclear receptors retinoic-acid-receptor-related orphan receptors α and γt (RORα and RORγt, respectively) have indispensible roles in the development of this cell type4,5,6,7. Here we present SR1001, a high-affinity synthetic ligandâthe first in a new class of compoundâthat is specific to both RORα and RORγt and which inhibits TH17 cell differentiation and function. SR1001 binds specifically to the ligand-binding domains of RORα and RORγt, inducing a conformational change within the ligand-binding domain that encompasses the repositioning of helix 12 and leads to diminished affinity for co-activators and increased affinity for co-repressors, resulting in suppression of the receptorsâ transcriptional activity. SR1001 inhibited the development of murine TH17 cells, as demonstrated by inhibition of interleukin-17A gene expression and protein production. Furthermore, SR1001 inhibited the expression of cytokines when added to differentiated murine or human TH17 cells. Finally, SR1001 effectively suppressed the clinical severity of autoimmune disease in mice. Our data demonstrate the feasibility of targeting the orphan receptors RORα and RORγt to inhibit specifically TH17 cell differentiation and function, and indicate that this novel class of compound has potential utility in the treatment of autoimmune diseases.
核受体RORδ±和RORδ³t(
视黄酸受体相关孤儿受体δ±和δ³t)对TH17细胞(产生白细胞介素-17的T辅助细胞)的发育至关重要。两个研究小组报告了 ROR δ³t
抑制剂的鉴定结果,这些化合物可能具有治疗自身免疫性疾病的潜力。Huh 等人在基于昆虫细胞的报告系统中进行了
化学筛选,发现强心甙
地高辛和各种衍
生物是 RORγt 转录活性的
抑制剂。通过这种机制,这些化合物能阻止小鼠 TH17 细胞的分化,并抑制体外人类 T 细胞白细胞介素-17 的产生。Solt 等人描述了一种名为 SR1001 的合成
配体,这种
配体可作为 RORα 和 RORγt 的反向激动剂发挥作用,研究表明它能阻止 TH17 细胞在体外发育,并能抑制小鼠实验性脑脊髓炎。产生白细胞介素-17 的 T 辅助细胞(TH17 细胞)是最近发现的一种 C
D4+ T 细胞亚群,在自身免疫性疾病中具有明显的病理作用1,2,3。核受体
视黄酸受体相关孤儿受体δ±和δ³t(分别为 ROR δ±和 RORδ³t)在这种细胞类型的发育过程中发挥着不可或缺的作用4,5,6,7。我们在这里介绍一种高亲和力合成
配体 SR1001,它是一类新型化合物中的第一种,对 RORα 和 RORγt 都具有特异性,能抑制 TH17 细胞的分化和功能。SR1001 能与 RORα 和 RORγt 的
配体结合结构域特异性结合,诱导
配体结合结构域内的构象变化,其中包括螺旋 12 的重新定位,导致对共激活剂的亲和力降低,对共
抑制剂的亲和力增加,从而抑制受体的转录活性。通过抑制白细胞介素-17A
基因的表达和蛋白的产生,SR1001抑制了小鼠TH17细胞的发育。此外,SR1001 还能抑制已分化的小鼠或人类 TH17 细胞中细胞因子的表达。最后,SR1001 能有效抑制小鼠自身免疫性疾病的临床严重程度。我们的数据证明了靶向孤儿受体 RORα 和 RORγt 特异性抑制 TH17 细胞分化和功能的可行性,并表明这一类新型化合物在治疗自身免疫性疾病方面具有潜在的用途。