單層奈米碳管於肺部上皮細胞中藉由影響Annexin A1與NF-κB間蛋白質交互作用減弱發炎訊號

Abstract

單層奈米碳管為一種廣泛使用的奈米材料，被認為是極具潛力的生物材料，包含了當作感測元件與藥物載體等。但在大量使用奈米材料的同時，我們對其潛在的毒性了解並不詳細。過去文獻中顯示，奈米顆粒可藉由與蛋白質間的交互作用影響細胞內訊息傳遞，進而造成細胞傷害。雖然奈米顆粒與特定蛋白質間的作用已有許多相關研究，但其對於蛋白質複合體的影響了解並不多。在本篇研究中，我們藉由電泳與液態層析質譜儀分析發現單層奈米碳管會與肺上皮細胞中Annexin A1 (ANXA1)蛋白結合；過去研究已知ANXA1參與生物體內發炎反應之調控，並藉由與NF-kappa B (NF-κB)形成蛋白質複合體，進而影響NF-κB下游訊息傳遞。我們的研究結果顯示，ANXA1與NF-κB所形成的複合體會被短的單層奈米碳管 (0.7 to 3 μm) 干擾而分開，此干擾並不會導致NF-κB下游訊號的活化，相反的會去抑制NF-κB的訊息傳遞路徑。在給予Tumor Necrosis Factor-α (TNF-α) 的刺激下，活化的NF-κB轉移到細胞核的量會顯著的被單層奈米碳管抑制；NF-κB下游調控的Interleukin-8 (IL-8)表現量也會同時下降。綜合以上，我們目前研究結果顯示，ANXA1為單層奈米碳管在肺上皮細胞中可能的結合蛋白，而單層奈米碳管可藉由與ANXA1之作用，影響ANXA1/NF-κB蛋白質複合體，進而干擾NF-κB下游路徑的傳遞。此研究提供了單層奈米碳管在肺上皮細胞調控免疫反應可能之機轉與證據。

Single-walled carbon nanotubes (SWCNTs), one of the most popular used nanomaterials, have been developed as potential biomaterials or drug carriers. However, these nanomaterials may have some adverse effects or toxicities, which may be partly caused by interaction with some cellular proteins, but the mechanism is still unclear. Here, the SWCNTs-binding proteins or if SWCNTs can interact with certain protein complex were discovered in lung epithelial cells. By the electrophoresis and liquid chromatography-mass spectrometry (LCMS/MS), the ex-vivo result showed that Annexin A1 (ANXA1) is one of the potential candidates of SWCNTs-binding proteins. Since ANXA1 has been reported involving in inflammatory signaling and plays an important role in the activation of NF-κB signaling through protein-protein interaction. Our results demonstrated that the protein complex of ANXA1 and NF-κB could be interrupted by short form of SWCNTs (0.7 to 3 μm) both in vitro and ex-vivo. Importantly, TNF-α induced nucleus translocation of NF-κB and up-regulation of IL-8 expression were significantly decreased via treatment with SWCNTs (10 μg/ml) in human lung epithelial cells (A549 and Beas2b cells). According to our results, ANXA1 is a novel binding protein of SWCNTs. Through binding with ANXA1, SWCNTs can inhibit TNF-α induced NF-κB inflammatory cascade via interfering the protein complex of ANXA1/NF-κB in lung epithelial cells. This study provides the potential evidence and mechanisms to show how the SWCNTs can regulate immuno-response in pulmonary epithelial cells.