人胰岛淀粉样多肽的聚集,或者hIAPP,与II型糖尿病(T2DM)的β细胞死亡有关。不同的胰腺β细胞环境变量,如pH,胰岛素和金属离子在控制hIAPP聚集中起关键作用。由于胰岛素和hIAPP是共同分泌的,从许多研究中已知,胰岛素通过阻止最初的二聚化过程来抑制hIAPP纤颤。另一方面,锌和铜各自对hIAPP纤颤有抑制作用,但是铜促进了有毒低聚物的产生。有趣的是,当一起测试胰岛素和锌的作用时,胰岛素寡聚平衡由锌离子的浓度控制。较低的锌浓度导致平衡向胰岛素的单体和二聚体状态转变,与单体hIAPP结合并阻止其发展成原纤维。另一方面,铜和胰岛素的联合作用尚未实现。在这项研究中,我们已经证明了铜的存在如何影响hIAPP聚集以及在有或没有胰岛素的情况下所得构象异构体的毒性。为此,我们使用了一套生物物理技术,包括NMR,荧光,CD等。,结合AFM和细胞毒性测定。在存在和/或不存在胰岛素的情况下,铜诱导hIAPP形成结构不同的稳定的毒性低聚物,阻止纤颤过程。更具体地说,在胰岛素存在下产生的寡聚体比在不存在胰岛素的情况下产生的寡聚体具有略高的毒性。这项研究将增加我们对两种β细胞环境因素对hIAPP聚集的联合调节作用的理解。
Aggregation of the human islets amyloid polypeptide, or
hIAPP, is linked to β-cell death in type II diabetes mellitus (T2DM). Different pancreatic β-cell environmental variables such as pH, insulin and metal ions play a key role in controlling the
hIAPP aggregation. Since insulin and
hIAPP are co-secreted, it is known from numerous studies that insulin suppresses
hIAPP fibrillation by preventing the initial dimerization process. On the other hand, zinc and copper each have an inhibitory impact on
hIAPP fibrillation, but copper promotes the production of toxic oligomers. Interestingly, the insulin oligomeric equilibrium is controlled by the concentration of zinc ions when the effect of insulin and zinc has been tested together. Lower zinc concentrations cause the equilibrium to shift towards the monomer and dimer states of insulin, which bind to monomeric hIAPP and stop it from developing into a fibril. On the other hand, the combined effects of copper and insulin have not yet been studied. In this study, we have demonstrated how the presence of copper affects hIAPP aggregation and the toxicity of the resultant conformers with or without insulin. For this purpose, we have used a set of biophysical techniques, including NMR, fluorescence, CD etc., in combination with AFM and cell cytotoxicity assay. In the presence and/or absence of insulin, copper induces
hIAPP to form structurally distinct stable toxic oligomers, deterring the fibrillation process. More specifically, the oligomers generated in the presence of insulin have slightly higher toxicity than those formed in the absence of insulin. This research will increase our understanding of the combined modulatory effect of two β-cell environmental factors on hIAPP aggregation.