Multi-walled carbon nanotubes (MWCNTs) are known to induce pulmonary inflammatory effects through stimulating pro-inflammatory cytokine secretion from alveolar macrophages. Despite extensive studies on MWCNTs’ pro-inflammatory reactivity, the understanding of molecular mechanisms involved is still incomplete. In this study, we investigated hemichannel’s involvement in MWCNTs-induced macrophage IL-1β release. Our results showed that the unmodified and COOH MWCNTs could induce ATP release and ATP-P2X₇R axis-dependent IL-1β secretion from THP-1 macrophages. By using various inhibitors, we confirmed that the MWCNTs-induced ATP release was primarily through hemichannels. EtBr dye uptake assay detected significant hemichannels opening in MWCNTs exposed THP-1 macrophages. Inhibition of hemichannels by CBX, ⁴³Gap27, or ¹⁰Panx1 pretreatment results in decreased ATP and IL-1β release. The addition of ATP restored the reduced IL-1β secretion level from hemichannel inhibition. We also confirmed with five other types of MWCNTs that the induction of hemichannels by MWCNTs strongly correlates with their capacity to induce IL-1β secretion. Taken together, we conclude that hemichannels-mediated ATP release and subsequent NLRP3 inflammasome activation through P2X₇R may be one mechanism by which MWCNTs induce macrophage IL-1β secretion. Our findings may provide a novel molecular mechanism for MWCNTs induced IL-1β secretion.

已知多壁碳纳米管（MWCNT）通过刺激肺泡巨噬细胞的促炎性细胞因子分泌来诱导肺部炎性作用。尽管对MWCNTs的促炎反应性进行了广泛的研究，但对涉及的分子机制的理解仍不完全。在这项研究中，我们调查了半通道参与MWCNTs诱导巨噬细胞IL-1β释放。我们的结果表明，未修饰的和COOH MWCNTs可以诱导THP-1巨噬细胞释放ATP和依赖于ATP-P2X ₇ R轴的IL-1β分泌。通过使用各种抑制剂，我们证实了MWCNTs诱导的ATP释放主要是通过半通道。EtBr染料摄取测定法检测到暴露于THP-1巨噬细胞的MWCNT中显着的半通道开放。CBX抑制半通道，⁴³ Gap27或¹⁰ Panx1预处理可导致ATP和IL-1β释放减少。ATP的添加通过半通道抑制恢复了降低的IL-1β分泌水平。我们还用其他五种类型的MWCNT证实了MWCNT诱导半通道与它们诱导IL-1β分泌的能力密切相关。两者合计，我们得出结论，半通道介导的ATP释放和随后通过P2X ₇ R激活的NLRP3炎性小体可能是MWCNTs诱导巨噬细胞IL-1β分泌的一种机制。我们的发现可能为MWCNTs诱导IL-1β分泌提供了新的分子机制。