5,6,7,8-Tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine derivative attenuates lupus nephritis with less effect to thymocyte development.

Retinoic­acid­receptor­related 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.

The Inhibitory Effects of Pentacyclic Triterpenes from Loquat Leaf against Th17 Differentiation.

BACKGROUND: Loquat leaf is an herb that is commonly used in traditional Chinese medicine (TCM) for its anti-inflammatory properties. Numerous studies have demonstrated that Th17 cells play a fundamental role in mediating SLE pathological deterioration. In our study, we investigated the inhibitory effect of pentacyclic triterpenes from loquat leaf on T helper 17 (Th17) cells and the therapeutic efficacy of OA in Lupus nephritis (LN) development. METHODS: We isolated three pentacyclic triterpene compounds rom loquat leaf by bioassay-directed fractionation and separation method. There were methyl corosolate (MC), uvaol (UL), and oleanolic acid (OA) Firstly, we elucidated Retinoic acid receptor-related orphan receptor gamma t (RORγt) inhibitory activity of these three compounds in the cell-based assay and Th17 differentiation in vitro assay. Then, we used OA-treated pristine-induced LN mice to evaluate the therapeutic effects of OA in LN development. Anti-dsDNA level in serum was detected by enzyme-linked immunosorbent assay (ELISA), interleukin 17A (IL-17A) and interferon-γ (IFN-γ) expression in spleen cells by Flow cytometry (FCM), histomorphologic examination of kidneys were performed by periodic acid schiff (PAS) staining and immunofluorescence analysis. RESULTS: Pentacyclic triterpene compounds (MC, UL, OA) displayed inhibition of RORγt activity in cell-based assay and Th17 differentiation in vitro. Furthermore, our results also showed that OA could significantly decrease serum anti-dsDNA antibody levels, IL-17A and IFN-γ expression and alleviate renal pathological damage in OA-treated group mice than in the model group mice. CONCLUSION: These results demonstrated that OA can improve the clinical manifestation of LN, indicating potential application in SLE therapy.