O-GlcNAc转移酶抑制剂的发现

O-GlcNAc transferase (OGT), one of essential mammalian enzymes, catalyses the transfer of N-acetylglucosamine from UDP-N-acetylglucosamine (UDP-GlcNAc) to hydroxyl groups of serines and threonines (Ser / Thr) in proteins. O-GlcNAcylation is widely located in cytoplasm and nucleus. This kind of protein post-translational modification is involved in the regulation of many cellular signaling pathways and closely associated with the occurrences and developments of numerous critical illnesses. However, research reports of OGT inhibitors are very limited and the half inhibitory concentration (IC50) of the best inhibitor is in a micromolar range. The lack of a rapid and simple method for monitoring OGT activity has impeded the efficient discovery of potent OGT inhibitors. In this project, target-guided synthesis avoids the dependence of high-throughput activity assays. With the concept of combinatorial chemistry, in situ click chemistry approach employs OGT as a template for self-assembling inhibitors with high activities from complementary building blocks. This will be significant for the clarifications of function and regulatory mechanism of O-GlcNAcylation and establish the foundation for the development of therapeutic drugs for relevant diseases.

O-GlcNAc转移酶是一种哺乳动物必需的酶，其将单个的N-乙酰氨基葡萄糖（GlcNAc）以O-糖苷键连接到蛋白质的丝氨酸和苏氨酸（Ser / Thr）羟基上。O-GlcNAc糖基化在细胞质和细胞核中广泛地存在，这种蛋白质的翻译后修饰对细胞内的许多信号通路具有调节作用，并与多种重大疾病的发生和发展密切相关。然而，针对O-GlcNAc转移酶抑制剂的研究报道十分有限，目前活性最好的抑制剂IC50仅在微摩尔水平。发现O-GlcNAc转移酶抑制剂的一个主要障碍是缺少快速简单的O-GlcNAc转移酶活性测定方法。在本项目中，以O-GlcNAc转移酶为模板，利用原位点击化学使合适的构建模块自组装，避免了高通量活性测定方法的依赖，以组合化学的理念，靶标导向合成高活性的抑制剂。这对于阐明O-GlcNAc糖基化的功能和调节机制有重要意义，为发展相关疾病的治疗性药物奠定了基础。

O-GlcNAc转移酶（O-GlcNAc transferase，OGT）是一种关键酶，其参与细胞核和细胞质内的动态O-GlcNAc糖基化。发现细胞可渗透的OGT抑制剂对于阐明O-GlcNAc糖基化的功能和调节机制具有重要意义，为发展相关疾病的治疗性药物奠定了基础。在本项目中，利用捆绑式原位点击化学（Tethering in situ click chemistry，TISCC），从低活性的前体（IC50 > 1 mM）出发，得到两种细胞可渗透的OGT抑制剂（APNT和APBT）。这两种抑制剂能够在细胞中降低O-GlcNAc糖基化水平，而没有明显的细胞毒性。对于OGT不寻常的非竞争性抑制有助于发现新的抑制剂和探索OGT的调节机制。这些分子的发现表明TISSC能够从非常弱活性的构建模块出发，发现新的先导化合物。