Abstract Direct contact with multi-walled carbon nanotubes (MWCNTs) could compromise the viability of macrophages, but the mechanisms remained poorly understood. Previously we investigated the cytotoxicity of MWCNTs with different diameters (XFM4 XFM22 > XFM34. In this study, we analyzed the transcriptomic data and found that MWCNTs diameter-dependently (in an order of XFM4 > XFM22 > XFM34) affected gene ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways related with immune responses. Therefore, we speculated that MWCNT-induced cytotoxicity was inflammation-driving pyroptosis. To test this hypothesis, we investigated the changes of morphologies, reactive oxygen species (ROS) and key proteins related with pyroptosis. We found that only XFM4 induced multi-pores of cellular membranes and ROS. Meanwhile, MWCNTs promoted the protein levels of caspase 1, NLRP3, interleukin-18 (IL-18) and IL-1β, and the observed effects were typically more obvious for XFM4 compared with XFM22 or XFM34. Finally, we found that transfection with casp1 or nlrp3 siRNA down-regulated both pro-caspase 1 and NLRP3 proteins and consequently inhibited the cytotoxicity of XFM4. In conclusion, the results from this study suggested that MWCNTs induced pyroptosis in THP-1 macrophages. XFM4 more effectively promoted pyroptosis compared with XFM22 or XFM34, which could provide a basis for rational design of biocompatible MWCNTs.

中文翻译：

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转录组学分析表明，多壁碳纳米管直径依赖性诱导 THP-1 巨噬细胞细胞焦亡

摘要 与多壁碳纳米管 (MWCNT) 直接接触可能会损害巨噬细胞的生存能力，但其机制仍知之甚少。之前我们研究了不同直径的多壁碳纳米管的细胞毒性（XFM4 XFM22 > XFM34。在这项研究中，我们分析了转录组数据，发现多壁碳纳米管直径依赖性（按 XFM4 > XFM22 > XFM34 的顺序）影响基因本体（GO）术语和京都基因和基因组百科全书 (KEGG) 通路与免疫反应相关。因此，我们推测 MWCNT 诱导的细胞毒性是炎症驱动的细胞焦亡。为了验证这一假设，我们调查了形态、活性氧 (ROS) 和与细胞焦亡相关的关键蛋白质。我们发现只有XFM4诱导细胞膜和ROS的多孔。同时，MWCNTs 促进了 caspase 1、NLRP3、白细胞介素-18 (IL-18) 和 IL-1β 的蛋白质水平，与 XFM22 或 XFM34 相比，XFM4 的观察效果通常更明显。最后，我们发现用 casp1 或 nlrp3 siRNA 转染下调 pro-caspase 1 和 NLRP3 蛋白，从而抑制 XFM4 的细胞毒性。总之，这项研究的结果表明 MWCNTs 诱导了 THP-1 巨噬细胞的细胞焦亡。与XFM22或XFM34相比，XFM4能更有效地促进细胞焦亡，为合理设计生物相容性多壁碳纳米管提供依据。我们发现用 casp1 或 nlrp3 siRNA 转染下调 pro-caspase 1 和 NLRP3 蛋白，从而抑制 XFM4 的细胞毒性。总之，这项研究的结果表明 MWCNTs 在 THP-1 巨噬细胞中诱导了细胞焦亡。与XFM22或XFM34相比，XFM4能更有效地促进细胞焦亡，为合理设计生物相容性多壁碳纳米管提供依据。我们发现用 casp1 或 nlrp3 siRNA 转染下调 pro-caspase 1 和 NLRP3 蛋白，从而抑制 XFM4 的细胞毒性。总之，这项研究的结果表明 MWCNTs 在 THP-1 巨噬细胞中诱导了细胞焦亡。与XFM22或XFM34相比，XFM4能更有效地促进细胞焦亡，为合理设计生物相容性多壁碳纳米管提供依据。