Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; University of the Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
Int J Biol Macromol. 2022 Jan 1;194:556-562. doi: 10.1016/j.ijbiomac.2021.11.098. Epub 2021 Nov 22.
TGFβ1 signaling pathway is associated with many diseases, which can induce the activation of hepatic stellate cells (HSCs) and induce liver fibrosis. Studies have shown that 20S-protopanaxadiol (PPD) has a therapeutic effect on liver fibrosis, but the target is unknown. In this study, we confirmed that PPD reduced the mRNA expression of downstream genes of the TGFβ1 pathway, which suggesting PPD is associated with the TGFβ1 pathway. The protein dissociation temperature and dissociation constant (Kd) of PPD on TGFβR1 and TGFβR2 were determined, which showed that PPD combined with TGFβR1 (Kd = 1.54 μM). The docking and simulation methods were used to find their binding sites. Site mutations, protein expression and in vitro binding experiments were performed to demonstrated these sites. In particular, these sites of TGFβR1 were also the active sites of TGFβR2. Therefore, we speculated that PPD blocked the combination of TGFβR1 and TGFβR2 by binding to the D57, R58, P59, and N78 of the TGFβR1 extracellular domain. Thus, PPD could block the transmission of TGFβ1 pathway and inhibit the activation of HSCs, and treating fibrosis. Our studies showed that PPD has the potential to treat diseases related to the TGFβ1 pathway and broadens its clinical application.
TGFβ1 信号通路与许多疾病有关，它可以激活肝星状细胞（HSCs）并诱导肝纤维化。研究表明，20S-原人参二醇（PPD）对肝纤维化有治疗作用，但靶点未知。在本研究中，我们证实 PPD 降低了 TGFβ1 通路下游基因的 mRNA 表达，这表明 PPD 与 TGFβ1 通路有关。测定了 PPD 对 TGFβR1 和 TGFβR2 的蛋白解离温度和解离常数（Kd），结果表明 PPD 与 TGFβR1 结合（Kd=1.54μM）。采用对接和模拟方法寻找它们的结合位点。进行了位点突变、蛋白表达和体外结合实验，以证明这些位点。特别是，TGFβR1 的这些位点也是 TGFβR2 的活性位点。因此，我们推测 PPD 通过与 TGFβR1 细胞外结构域的 D57、R58、P59 和 N78 结合，阻断 TGFβR1 和 TGFβR2 的结合。因此，PPD 可以阻断 TGFβ1 通路的传递，抑制 HSCs 的激活，从而治疗纤维化。我们的研究表明，PPD 具有治疗与 TGFβ1 通路相关疾病的潜力，并拓宽了其临床应用。
