Nitrogen-Doped Graphene Quantum Dot-Combined Sodium 10-Amino-2-methoxyundecanoate:Studies of Proinflammatory Gene Expression and Live Cell Imaging

摘要

Marine cyanobacteria are renowned for producing bioactive secondary metabolites with great structural diversity via mixed biosynthetic pathways. Lyngbya sp., a marine cyanobacterium, produces many metabolites with anti-inflammatory potentials; nevertheless, its bioactive metabolites exercising providing protection against inflammation has been deciphered inadequate. In this study, the ethanolic fraction of the Lyngbya sp. extract was purified and identified as sodium 10-amino-2-methoxyundecanoate (>SAM) using Fourier-transform infrared spectroscopy, nuclear magnetic resonance, and electron spray ionization-mass spectroscopy. >SAM showed prominent inhibition of inflammation, which was analyzed by reactive oxygen species generation and nitric oxide (NO) inhibition assay. Furthermore, the anti-inflammatory potentials of >SAM were evaluated in lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cell lines by fluorescence-activated cell sorting analysis, which evidenced prominent decrease in COX-2 expression (∼90%) with >SAM-treated cells than the control. Subsequently, a semiquantitative real-time polymerase chain reaction analysis alsorevealed the downregulation of COX-2, iNOS, TNF-α, NF-κß, IL-1α, IL-1ß, IL-4, and IL-6 gene expression in >SAM-treated LPS-induced RAW 264.7 cells. To further enhance the deliveryof >SAM into the cells, it was combined with N-doped graphenequantum dots (N-GQDs) for the anti-inflammatory potentials. It resultedin improved downregulation of COX-2, iNOS, TNF-α, NF-κß, IL-1α, IL-1ß, IL-4, and IL-6 than cells treated with >SAM alone. Conclusively, N-GQDs combined with >SAM havethe effective therapeutic potential as an inhibitor of inflammationby modulating the expression of different cytokine genes.