含硒藻胆蛋白拮抗人胰淀素诱导的胰岛β细胞凋亡的作用机理

Amyloid protein and depositions formed by misfolded proteins have been identified as an important causative factor of these diseases, including type 2 diabetics. Islet amyloid deposition formed by human amylin (hA) could induce pancreatic β cell dysfunction, and finally resulting in cell apoptosis. Many studies have showed that inhibition of hA aggregation could effectively reverse the β cell apoptosis. Therefore, hA could be a good target for the therapeutics of type 2 diabetics. Our pervious studies showed that, phycocyanin purified from Spirulina, could protect pancreatic βcells against hA-induced apoptosis. In this proposal, we will continue to investigate the interaction mechanisms between selenium-containing phycobiliproteins (Se-PbP) and hA by using ThT fluorescence analysis, AFM, MALDI-TOF/MS and EPR analysis. The effects of Se-PbP on the apoptotic signaling pathways, such as MAPK, p53, AKT, intrinsic and extrinsic apoptosis pathways, will also be studies by real-time PCR and Western blotting. The protective effects of Se-PbP on β cells will also be further examined in hA-over-expressing cell line and primary islet cells. This project could provide scientific information for searching for novel type 2 diabetics therapeutics with clear target and action mechanisms.

人胰淀素（human amylin, hA）错误折叠形成的胰岛淀粉样蛋白沉积具有损伤胰岛β细胞功能及诱导β细胞凋亡的作用。研究表明，抑制hA的聚集可有效减少β细胞的凋亡。因此，hA 已成为2 型糖尿病治疗的一个新靶点。我们的前期研究发现，螺旋藻的活性成分藻蓝蛋白能够有效抑制hA诱导的胰岛β细胞凋亡。在此基础上，本项目将研究含硒藻胆蛋白对hA诱导的胰岛细胞凋亡的拮抗作用及其分子机制；基于ThT荧光分析、AFM、MALDI-TOF/MS等技术，分析含硒藻胆蛋白与hA的相互作用机理；应用实时荧光定量PCR法和Western blot法考察含硒藻胆蛋白对hA激活的MAPK、p53信号通路、死亡受体和线粒体凋亡信号通路等的阻断作用；建立高表达hA的转基因细胞株和分离大鼠原代胰岛细胞，进一步检测含硒藻胆蛋白对胰岛β细胞的保护作用。本研究可为寻找和开发靶点清楚、机制明确的2型糖尿病治疗药物提供科学依据。

人胰淀素（human islet amyloid polypeptide, hIAPP）错误折叠形成的胰岛淀粉样蛋白沉积具有损伤胰岛β细胞功能及诱导β细胞凋亡的作用。研究表明，抑制hA的聚集可有效减少β细胞的凋亡。因此，hIAPP 已成为2 型糖尿病治疗的一个新靶点。本项目研究了有机硒包括含硒藻胆蛋白和硒化合物对hIAPP诱导的胰岛细胞凋亡的拮抗作用及其分子机制，获得了许多有意义的数据。ThT荧光分析、粒度分析、CD图谱、AFM和TEM证明Se-PC介入hIAPP分子间结合，抑制hIAPP的纤维化，促进hIAPP纳米颗粒的形成。Se-PC缓解了hIAPP诱导的细胞凋亡，具有保护作用。.通过ThT荧光探针法发现硒杂环化合物（SePD）可以有效的抑制hIAPP的纤维化程度，SePD是通过抑制细胞线粒体凋亡通路来逆转hIAPP诱导的细胞凋亡。此外，我们还发现钌配合物也能有效地抑制hIAPP的聚集和保护胰岛细胞。本研究为寻找和开发靶点清楚、机制明确的2型糖尿病治疗药物提供科学依据。课题研究成果在J. Mater. Chem、Chemistry-An Asian Journal 及Journal of Inorganic Biochemistry,等主流杂志发表论文18篇，超过了预期的目标。