Length effects on the dynamic process of cellular uptake and exocytosis of single-walled carbon nanotubes in murine macrophage cells.
Length effects on the dynamic process of cellular uptake and exocytosis of single-walled carbon nanotubes in murine macrophage cells.
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长度对小鼠巨噬细胞单壁碳纳米管摄取和胞吐动态过程的影响
DOI：
10.1038/s41598-017-01746-9
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发表时间：
2017-05-10
影响因子：
4.6
通讯作者：
Guo LH
中科院分区：
文献类型：
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作者：
Cui X;Wan B;Yang Y;Ren X;Guo LH
单壁碳纳米管的细胞摄取和胞吐作用是决定其细胞内浓度和效应的基本过程。尽管酸氧化的单壁碳纳米管在生物医学领域具有巨大的潜力，但对这些过程的影响因素的理解需要加深。在这里，我们定量研究了巨噬细胞中三种长度的单壁碳纳米管的摄取和胞吐作用-630（±171）nm（L-SWCNT），390（±50）nm（M-SWCNT）和195（±63）nm（S-MWCNT）。结果表明，细胞内单壁碳纳米管的积累是一个非长度依赖性的非单调过程，在8 h时单壁碳纳米管积累最多（3950 fg/cell），随后细胞内单壁碳纳米管的积累量随时间明显下降。单壁碳纳米管的摄取率随浓度的增加而降低，表明细胞内单壁碳纳米管的积累是一个饱和过程。在更新培养基后，我们发现随着时间的推移，上清液中的单壁碳纳米管增加，细胞内的单壁碳纳米管减少，证实发生了胞吐作用。内吞途径的选择性抑制表明，单壁碳纳米管的内化涉及几个途径，在大胞饮>小窝介导的内吞>网格蛋白依赖的内吞。有趣的是，网格蛋白介导的内吞作用对于内化较短的单壁碳纳米管相对重要。本研究揭示的单壁碳纳米管吸收和胞吐的动态过程和机制可以更好地理解单壁碳纳米管的毒性，并有助于设计具有减轻毒性和预期功能的碳纳米管产品。
Cellular uptake and exocytosis of SWCNTs are fundamental processes determining their intracellular concentration and effects. Despite the great potential of acid-oxidized SWCNTs in biomedical field, understanding of the influencing factors on these processes needs to be deepened. Here, we quantitatively investigated uptake and exocytosis of SWCNTs in three lengths-630 (±171) nm (L-SWCNTs), 390 (±50) nm (M-SWCNTs), and 195 (±63) nm (S-MWCNTs) in macrophages. The results showed that the cellular accumulation of SWCNTs was a length-independent process and non-monotonic in time, with the most SWCNTs (3950 fg/cell) accumulated at 8 h and then intracellular SWCNTs dropped obviously with time. The uptake rate of SWCNTs decreased with increasing concentration, suggesting that intracellular SWCNTs accumulation is a saturable process. After refreshing culture medium, we found increasing SWCNTs in supernatant and decreasing intracellular SWCNTs over time, confirming the exocytosis occurred. Selective inhibition of endocytosis pathways showed that the internalization of SWCNTs involves several pathways, in the order of macropinocytosis> caveolae-mediated endocytosis> clathrin-dependent endocytosis. Intriguingly, clathrin-mediated endocytosis is relatively important for internalizing shorter SWCNTs. The dynamic processes of SWCNTs uptake and exocytosis and the mechanisms revealed by this study may render a better understanding on SWCNT toxicity and facilitate the design of CNT products with mitigated toxicity and desired functions.