Department of Cell and Molecular Biology, School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, 39406, USA.
Division of Fundamental Neurobiology, University Health Network, Toronto, ON, M5T 2S8, Canada.
Inflammation. 2020 Apr;43(2):744-751. doi: 10.1007/s10753-019-01161-4.
Mast cell activation triggers intricate signaling pathways that promote the expression and/or release of a wide range of mediators including tumor necrosis factor (TNF; also known as TNFα). In this study, we investigated the connection between TNF secretion and TNF production, exploiting RBL-2H3 cells (a tumor analog of mucosal mast cells) that are depleted of Munc13-4, a crucial component of the mast cell exocytic machinery. We showed that antigen/IgE elicited robust TNF production in RBL-2H3 cells, but not in Munc13-4 knockout cells. The production defect was corrected when Munc13-4 was reintroduced into the knockout cell line, suggesting that the phenotype was not caused by any secondary effect derived from the knockout approach. Furthermore, pre-incubation of RBL-2H3 cells with R-7050, an antagonist of TNF receptor-dependent signaling, was shown to block TNF production without inhibiting TNF release. These observations provide fresh evidence for a robust feed-back loop to boost TNF production in activated mast cells.
肥大细胞活化触发复杂的信号通路，促进包括肿瘤坏死因子（TNF；也称为 TNFα）在内的广泛介质的表达和/或释放。在这项研究中，我们利用缺乏 Munc13-4（肥大细胞胞吐机制的关键组成部分）的 RBL-2H3 细胞（粘膜肥大细胞的肿瘤类似物），研究了 TNF 分泌与 TNF 产生之间的联系。我们表明，抗原/IgE 在 RBL-2H3 细胞中引发了强烈的 TNF 产生，但在 Munc13-4 敲除细胞中则没有。当将 Munc13-4 重新引入敲除细胞系时，纠正了产生缺陷，这表明该表型不是由敲除方法引起的任何二次效应引起的。此外，用 R-7050（一种 TNF 受体依赖性信号传导的拮抗剂）预先孵育 RBL-2H3 细胞，可在不抑制 TNF 释放的情况下阻断 TNF 产生。这些观察结果为激活的肥大细胞中 TNF 产生的强大反馈回路提供了新的证据。
