Shi Yue, Lv Wu, Jiao Ao, Zhang Chengshuo, Zhang Jialin
Hepatobiliary Surgery Department and Unit of Organ Transplantation, The First Hospital of China Medical University, Shenyang 110001, China.
Department of Geriatric Surgery, The First Hospital of China Medical University, Shenyang 110001, China.
Int J Endocrinol. 2019 Jan 29;2019:9062032. doi: 10.1155/2019/9062032. eCollection 2019.
The presence of amyloid deposits of human islet amyloid polypeptide (hIAPP) in islet -cells has been associated with type 2 diabetes occurrence and islet graft failure. Self-assembly into oligomers and fibrils during the process of aggregation by hIAPP can lead to failure and depletion of -cells. Studies have shown that some critical regions of hIAPP might contribute to the aggregation. Thus, many studies focused on finding the effective molecules, especially the short-peptide inhibitors, that bind to these regions and disrupt the aggregation of hIAPP. In the present study, a novel pentapeptide inhibitor Phe-Leu-Pro-Asn-Phe (FLPNF) was designed and its effectiveness on the inhibition of the formation of amyloid deposits was examined.
The binding mode between FLPNF and hIAPP was performed using molecular docking. The effectiveness of FLPNF on inhibiting hIAPP amyloid aggregation was tested by Thioflavin T (ThT) staining. Furthermore, negative stain electron microscopy was used to observe hIAPP fibrils. A biolayer interferometry analysis was used to identify the interaction between FLPNF and hIAPP. In addition, the cytotoxicity toward INS-1 cells was tested by a cell proliferation assay.
FLPNF was predicted to have a compact conformation to bind at the site of hIAPP. FLPNF strongly inhibited the amyloid aggregation of hIAPP at a 10 : 1 molar ratio . Coincubation of FLPNF with hIAPP decreased the amount of hIAPP fibrils. Furthermore, a direct interaction between FLPNF and hIAPP was confirmed. FLPNF could also decrease the cytotoxic effect of hIAPP.
The novel pentapeptide inhibitor FLPNF was constructed and inhibited the aggregation through direct binding to hIAPP. It is considered a suitable inhibitor for hIAPP amyloid deposit formation.
胰岛β细胞中存在人胰岛淀粉样多肽（hIAPP）的淀粉样沉积物与2型糖尿病的发生及胰岛移植失败有关。hIAPP在聚集过程中自组装成寡聚体和原纤维可导致β细胞功能衰竭和耗竭。研究表明，hIAPP的一些关键区域可能促成聚集。因此，许多研究致力于寻找能与这些区域结合并破坏hIAPP聚集的有效分子，尤其是短肽抑制剂。在本研究中，设计了一种新型五肽抑制剂苯丙氨酸-亮氨酸-脯氨酸-天冬酰胺-苯丙氨酸（FLPNF），并检测了其对淀粉样沉积物形成的抑制效果。
采用分子对接研究FLPNF与hIAPP的结合模式。通过硫黄素T（ThT）染色检测FLPNF抑制hIAPP淀粉样聚集的效果。此外，利用负染电子显微镜观察hIAPP原纤维。采用生物层干涉分析确定FLPNF与hIAPP之间的相互作用。另外，通过细胞增殖试验检测对INS-1细胞的细胞毒性。
预测FLPNF具有紧密构象，可结合于hIAPP的位点。FLPNF以10∶1的摩尔比强烈抑制hIAPP的淀粉样聚集。FLPNF与hIAPP共孵育可减少hIAPP原纤维的数量。此外，证实了FLPNF与hIAPP之间存在直接相互作用。FLPNF还可降低hIAPP的细胞毒性作用。
构建了新型五肽抑制剂FLPNF，其通过直接结合hIAPP抑制聚集。它被认为是hIAPP淀粉样沉积物形成的合适抑制剂。
