Retinoic‑acid‑receptor‑related orphan nuclear hormone receptor gamma t (RORγt), a critical transcriptional factor of Th17 cells, is a potential therapeutic target for Th17-mediated autoimmune diseases. In addition, RORγt is essential for thymocyte survival and lymph node development, and RORγt inhibition or deficiency causes abnormal thymocyte development, thymus lymphoma, and lymph node defect. Recent study demonstrated that specific regulation of Th17 differentiation related to the hinge region of RORγt. In this research, we investigated the effect of RORγt inhibitor, 5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine derivative (TTP), in the therapy of lupus nephritis and its safety on thymocyte development. We demonstrated that TTP repressed the development of Th17 cells and ameliorated the autoimmune disease manifestation in the pristane-induced lupus nephritis mice model. The treatment of TTP in the mice did not interfere with thymocyte development, including total thymocyte number and proportion of CD4⁺CD8⁺ double-positive populations in the thymus, and had no substantial effects on the pathogenesis of thymoma. The TTP had a stronger affinity with full-length RORγt protein compared with the truncated RORγt LBD region via surface plasmon resonance, which indicated TTP binding to RORγt beyond LBD region. Molecular docking computation showed that the best binding pocket of TTP to RORγt is located in the hinge region of RORγt. In summary, as a RORγt inhibitor, TTP had a potential to develop the clinical medicine for treating Th17-mediated autoimmune diseases with low safety risk for thymocyte development.

视黄酸受体相关孤儿核激素受体γt（RORγt）是Th17细胞的关键转录因子，是Th17介导的自身免疫性疾病的潜在治疗靶点。此外，RORγt对于胸腺细胞存活和淋巴结发育至关重要，RORγt抑制或缺陷会导致胸腺细胞发育异常、胸腺淋巴瘤和淋巴结缺陷。最近的研究表明，Th17分化的特异性调节与RORγt的铰链区相关。在本研究中，我们研究了 RORγt 抑制剂 5,6,7,8-四氢苯并[4,5]噻吩并[2,3-d]嘧啶衍生物 (TTP) 在狼疮性肾炎治疗中的作用及其安全性胸腺细胞发育。我们证明，在降植烷诱导的狼疮性肾炎小鼠模型中，TTP 可抑制 Th17 细胞的发育并改善自身免疫性疾病的表现。 TTP治疗小鼠并不会干扰胸腺细胞的发育，包括胸腺细胞总数和胸腺中CD4 ⁺ CD8 ⁺双阳性群体的比例，并且对胸腺瘤的发病机制没有实质性影响。通过表面等离振子共振，与截短的RORγt LBD区域相比，TTP与全长RORγt蛋白具有更强的亲和力，这表明TTP与LBD区域之外的RORγt结合。分子对接计算表明，TTP与RORγt的最佳结合口袋位于RORγt的铰链区。综上所述，TTP作为RORγt抑制剂，具有开发治疗Th17介导的自身免疫性疾病的临床药物的潜力，且对胸腺细胞发育的安全风险较低。