Consiglio Nazionale delle Ricerche, Istituto di Cristallografia, Sede Secondaria di Catania, Via Paolo Gaifami 18, 95126 Catania, Italy.
Department of Biochemistry, University of Zürich, Zürich CH-8057, Switzerland.
Biochim Biophys Acta Proteins Proteom. 2022 May 1;1870(5):140772. doi: 10.1016/j.bbapap.2022.140772. Epub 2022 Mar 17.
Type 2 Diabetes is a major public health threat, and its prevalence is increasing worldwide. The abnormal accumulation of islet amyloid polypeptide (IAPP) in pancreatic β-cells is associated with the onset of the disease. Therefore, the design of small molecules able to inhibit IAPP aggregation represents a promising strategy in the development of new therapies. Here we employ in vitro, biophysical, and computational methods to inspect the ability of Silybin A and Silybin B, two natural diastereoisomers extracted from milk thistle, to interfere with the toxic self-assembly of human IAPP (hIAPP). We show that Silybin B inhibits amyloid aggregation and protects INS-1 cells from hIAPP toxicity more than Silybin A. Molecular dynamics simulations revealed that the higher efficiency of Silybin B is ascribable to its interactions with precise hIAPP regions that are notoriously involved in hIAPP self-assembly i.e., the S20-S29 amyloidogenic core, H18, the N-terminal domain, and N35. These results highlight the importance of stereospecific ligand-peptide interactions in regulating amyloid aggregation and provide a blueprint for future studies aimed at designing Silybin derivatives with enhanced drug-like properties.
2 型糖尿病是一个主要的公共健康威胁，其患病率在全球范围内正在增加。胰岛淀粉样多肽（IAPP）在胰腺β细胞中的异常积累与疾病的发生有关。因此，设计能够抑制 IAPP 聚集的小分子代表了开发新疗法的一种有前途的策略。在这里，我们采用体外、生物物理和计算方法来检查水飞蓟宾 A 和水飞蓟宾 B（两种从奶蓟中提取的天然非对映异构体）抑制人 IAPP（hIAPP）毒性自组装的能力。我们表明，水飞蓟宾 B 比水飞蓟宾 A 更能抑制淀粉样蛋白聚集并保护 INS-1 细胞免受 hIAPP 的毒性。分子动力学模拟表明，水飞蓟宾 B 更高的效率归因于其与 hIAPP 自组装中涉及的精确区域的相互作用，即 S20-S29 淀粉样核心、H18、N 端结构域和 N35。这些结果强调了立体特异性配体-肽相互作用在调节淀粉样蛋白聚集中的重要性，并为未来旨在设计具有增强药物特性的水飞蓟宾衍生物的研究提供了蓝图。
