Anand Bibin G, Shekhawat Dolat S, Dubey Kriti, Kar Karunakar
Department of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur, Rajasthan 342011, India.
School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
ACS Biomater Sci Eng. 2017 Jun 12;3(6):1136-1145. doi: 10.1021/acsbiomaterials.7b00030. Epub 2017 May 12.
Because the process of insulin fibril assembly is linked to a multitude of medical problems, finding effective and biocompatible inhibitors against such an aggregation process could be beneficial. Targeting the aggregation-prone residues of insulin may perhaps work as an effective strategy to prevent the onset of insulin fibril assembly. In this work, we have synthesized uniform sized, thermostable gold nanoparticles (AuNPs) surface-functionalized with piperine to target amyloid-prone residues of insulin. We found that the process of both spontaneous and seed-induced amyloid formation of insulin was strongly inhibited in the presence of AuNPs. Surface functionalization of piperine was found to be critical to its inhibition effect because no such effect was observed for free piperine as well as for uncoated control gold nanoparticles. Fluorescence quenching data revealed binding of AuNPs with insulin's native structure which was further validated by docking studies that predicted viable H-bond and CH-π interactions between piperine and key aggregation-prone residues of insulin's B-chain. Our hemolysis assay studies further confirmed that these piperine coated nanoparticles were hemocompatible. Data obtained from both experimental and computational studies suggest that the retention of native structure of insulin and the ability of the piperine molecule to interact with the aggregation-prone residues of insulin are the key factors for the inhibition mechanism. The findings of this work may help in the development of nanoparticle-based formulations to prevent medical problems linked to insulin aggregation.
由于胰岛素纤维组装过程与众多医学问题相关，找到针对这种聚集过程的有效且生物相容的抑制剂可能会有所助益。靶向胰岛素中易于聚集的残基或许可作为一种预防胰岛素纤维组装发生的有效策略。在这项工作中，我们合成了尺寸均匀、热稳定的胡椒碱表面功能化金纳米颗粒（AuNPs），以靶向胰岛素的淀粉样蛋白易聚集残基。我们发现，在金纳米颗粒存在的情况下，胰岛素自发和种子诱导的淀粉样蛋白形成过程均受到强烈抑制。结果发现胡椒碱的表面功能化对其抑制作用至关重要，因为游离胡椒碱以及未包覆的对照金纳米颗粒均未观察到这种效果。荧光猝灭数据揭示了金纳米颗粒与胰岛素天然结构的结合，对接研究进一步验证了这一点，该研究预测了胡椒碱与胰岛素B链关键易聚集残基之间可行的氢键和CH-π相互作用。我们的溶血试验研究进一步证实这些胡椒碱包覆的纳米颗粒具有血液相容性。从实验和计算研究中获得的数据表明，胰岛素天然结构的保留以及胡椒碱分子与胰岛素易聚集残基相互作用的能力是抑制机制的关键因素。这项工作的发现可能有助于开发基于纳米颗粒的制剂，以预防与胰岛素聚集相关的医学问题。
