評估葉綠素鐵奈米粒子抑制及降解胰島類澱粉蛋白聚集的效果
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2025
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人類胰島類澱粉蛋白(islet amyloid polypeptide, IAPP)是一種以37個胺基酸所組成的胜肽，由胰臟的β細胞分泌，參與調節葡萄糖的代謝。然而胞外IAPP容易形成類澱粉蛋白纖維(amyloid)，造成β細胞死亡，進而降低β細胞的功能，是第二型糖尿病病患常見的病徵之一，因此在這項研究中，我們試圖藉由卟啉(porphyrin)衍生物葉綠素氧化鐵奈米粒子(Fe-C)抑制以及降解IAPP類澱粉蛋白纖維的形成。在過去的研究中發現具有卟啉結構的衍生物能夠作為光敏劑，在照光下藉由光動力療法(photodynamic therapy, PDT)生成活性氧，氧化類澱粉蛋白的胺基酸側鍊進而有效抑制以及降解類澱粉蛋白的聚集。在本研究中，我們先使用ThT之衍生物AmySP-4螢光動力學實驗觀察Fe-C對胰島類澱粉纖維形成的抑制效果及降解效果，並透過穿透式電子顯微鏡觀察纖維形貌的變化，再透過質譜檢測得知IAPP序列中氧化的胺基酸位點，由傅立葉轉換紅外線光譜儀輔助檢測含β-摺疊的IAPP纖維多寡，同時搭配縫孔墨跡法佐證IAPP纖維的含量以及尼羅紅(nile red)螢光測定IAPP纖維疏水性區域之變化，並進行INS-1細胞毒性的測試。我們發現Fe-C具有抑制及降解IAPP類澱粉蛋白纖維的能力，在光照的情況下效果更佳。在細胞毒性測試中，Fe-C具有生物相容性，經Fe-C照光降解的IAPP纖維片段降低了IAPP纖維對細胞的毒性，為第二型糖尿病及其他類澱粉蛋白沉積症提供有效的治療策略。
Human islet amyloid polypeptide (IAPP) is a 37-amino acid peptide secreted by pancreatic β-cells, playing a role in regulating glucose metabolism. However, extracellular IAPP readily forms amyloid fibrils, which impair β-cell functionality and represent a common pathological feature in patients with type 2 diabetes mellitus. In this study, we attempt to inhibit and degrade IAPP amyloid fibril formation using porphyrin-derived Fe3O4‑Chlorophyllin nanoparticles (Fe-C).In previous studies, porphyrin-based derivatives have been identified as effective photosensitizers for the generation of reactive oxygen species (ROS) via photodynamic therapy (PDT). The ROS produced can oxidize the amino acid side chains of amyloid, leading to the inhibition of amyloid aggregation and enhancement of their degradation. Here, we employed thioflavin-T derivative, AmySP-4, in fluorescence kinetics assays to evaluate the inhibitory and degradative effects of Fe-C on IAPP fibrils formation. The morphological changes were observed through transmission electron microscopy. The oxidation sites of IAPP were identified through mass spectrometry analysis. Fourier-transform infrared spectroscopy was used to probe the β-sheet conformation that IAPP fibrils adapted. Additionally, Nile red fluorescence assays were performed to assess changes in the hydrophobic regions of IAPP fibrils. The cytotoxicity of the samples was tested using INS-1. Our findings reveal that Fe-C nanoparticles effectively inhibit and degrade IAPP amyloid fibrils, with enhanced efficacy under light exposure. Fe-C also exhibited good biocompatibility, and the photodegraded IAPP fragments showed reduced cytotoxicity. This suggests that Fe-C nanoparticles providing therapeutic strategies for type 2 diabetes mellitus and other amyloidosis.
Human islet amyloid polypeptide (IAPP) is a 37-amino acid peptide secreted by pancreatic β-cells, playing a role in regulating glucose metabolism. However, extracellular IAPP readily forms amyloid fibrils, which impair β-cell functionality and represent a common pathological feature in patients with type 2 diabetes mellitus. In this study, we attempt to inhibit and degrade IAPP amyloid fibril formation using porphyrin-derived Fe3O4‑Chlorophyllin nanoparticles (Fe-C).In previous studies, porphyrin-based derivatives have been identified as effective photosensitizers for the generation of reactive oxygen species (ROS) via photodynamic therapy (PDT). The ROS produced can oxidize the amino acid side chains of amyloid, leading to the inhibition of amyloid aggregation and enhancement of their degradation. Here, we employed thioflavin-T derivative, AmySP-4, in fluorescence kinetics assays to evaluate the inhibitory and degradative effects of Fe-C on IAPP fibrils formation. The morphological changes were observed through transmission electron microscopy. The oxidation sites of IAPP were identified through mass spectrometry analysis. Fourier-transform infrared spectroscopy was used to probe the β-sheet conformation that IAPP fibrils adapted. Additionally, Nile red fluorescence assays were performed to assess changes in the hydrophobic regions of IAPP fibrils. The cytotoxicity of the samples was tested using INS-1. Our findings reveal that Fe-C nanoparticles effectively inhibit and degrade IAPP amyloid fibrils, with enhanced efficacy under light exposure. Fe-C also exhibited good biocompatibility, and the photodegraded IAPP fragments showed reduced cytotoxicity. This suggests that Fe-C nanoparticles providing therapeutic strategies for type 2 diabetes mellitus and other amyloidosis.
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胰島類澱粉蛋白, 光動力療法, 卟啉衍生物奈米粒子, Islet amyloid polypeptide, photodynamic therapy, porphyrin derivative-coated nanoparticles