LRRC8A is essential for hypotonicity-, but not for DAMP-induced NLRP3 inflammasome activation.
LRRC8A is essential for hypotonicity-, but not for DAMP-induced NLRP3 inflammasome activation.
复制标题
LRRC8A对低渗性是必需的，但对damp诱导的NLRP3炎性体激活不是必需的。
DOI：
10.7554/elife.59704
复制
发表时间：
2020-11-20
期刊：
影响因子：
7.7
通讯作者：
Brough D
中科院分区：
文献类型：
--
作者：
Green JP;Swanton T;Morris LV;El-Sharkawy LY;Cook J;Yu S;Beswick J;Adamson AD;Humphreys NE;Bryce R;Freeman S;Lawrence C;Brough D
NLRP 3炎性体是一种多分子蛋白质复合物，可将非活性细胞因子前体转化为活性形式的IL-1β和IL-18。NLRP 3炎性小体通常与非传染性疾病状态的破坏性炎症相关，并且被认为是有吸引力的治疗靶点。然而，关于NLRP 3激活的机制仍有许多未知之处。氯离子外流被认为是NLRP 3激活的重要步骤，但涉及哪些氯离子通道仍不清楚。我们使用化学、生物化学和遗传学方法来确定氯离子通道在调节小鼠巨噬细胞NLRP 3中的重要性。具体来说，我们确定LRRC 8A，体积调节阴离子通道（VRAC）的重要组成部分，作为一个重要的调节低渗诱导，但不是DAMP诱导，NLRP 3炎性小体激活。尽管LRRC 8A对于典型的DAMP依赖性NLRP 3活化是不敏感的，但这仍然对氯离子通道抑制剂敏感，这表明存在控制NLRP 3的额外的和特异性的氯离子感测和调节机制。炎症是健康免疫系统的重要组成部分，它保护我们免受有害病原体（如细菌或病毒）的侵害，并致力于恢复受损组织。在我们身体的免疫细胞中，炎症过程可以通过一组被称为NLRP 3炎性体复合物的炎症蛋白质激活。虽然炎症是一种保护人体的强大机制，但持续或不受控制的炎症可能会导致严重的长期损害。NLRP 3炎性体的不适当激活与几种疾病有关，包括阿尔茨海默病、心脏病和糖尿病。NLRP 3炎性体可以被不同的刺激激活，包括细胞体积的变化和暴露于受损细胞产生的分子或细菌毒素。然而，NLRP 3响应这些刺激而被激活的确切机制尚不清楚。已知氯离子从免疫细胞中退出会激活NLRP 3炎性体。氯离子通过称为阴离子通道的蛋白质离开细胞，包括体积调节阴离子通道（VRAC），其响应细胞体积的变化。绿色等人发现，在实验室中生长的小鼠免疫细胞（称为巨噬细胞）中，VRAC是当细胞体积变化时参与激活NLRP 3炎性体的唯一氯离子通道。然而，当巨噬细胞暴露于由受损细胞或细菌毒素产生的分子时，绿色等人发现其他先前未鉴定的氯离子通道参与激活NLRP 3炎性体。这些结果表明，有可能开发药物来防止NLRP 3炎性体的激活，该炎性体选择性地靶向特定的氯离子通道组，这取决于哪些刺激引起炎症。这种选择性方法将最小化与通过直接结合NLRP 3本身来抑制所有NLRP 3活性的药物相关的副作用。最终，这可能有助于指导新的靶向抗炎药物的开发，这些药物可以帮助治疗人类各种疾病的症状。
The NLRP3 inflammasome is a multi-molecular protein complex that converts inactive cytokine precursors into active forms of IL-1β and IL-18. The NLRP3 inflammasome is frequently associated with the damaging inflammation of non-communicable disease states and is considered an attractive therapeutic target. However, there is much regarding the mechanism of NLRP3 activation that remains unknown. Chloride efflux is suggested as an important step in NLRP3 activation, but which chloride channels are involved is still unknown. We used chemical, biochemical, and genetic approaches to establish the importance of chloride channels in the regulation of NLRP3 in murine macrophages. Specifically, we identify LRRC8A, an essential component of volume-regulated anion channels (VRAC), as a vital regulator of hypotonicity-induced, but not DAMP-induced, NLRP3 inflammasome activation. Although LRRC8A was dispensable for canonical DAMP-dependent NLRP3 activation, this was still sensitive to chloride channel inhibitors, suggesting there are additional and specific chloride sensing and regulating mechanisms controlling NLRP3. Inflammation is a critical part of a healthy immune system, which protects us against harmful pathogens (such as bacteria or viruses) and works to restore damaged tissues. In the immune cells of our body, the inflammatory process can be activated through a group of inflammatory proteins that together are known as the NLRP3 inflammasome complex. While inflammation is a powerful mechanism that protects the human body, persistent or uncontrolled inflammation can cause serious, long-term damage. The inappropriate activation of the NLRP3 inflammasome has been implicated in several diseases, including Alzheimer’s disease, heart disease, and diabetes. The NLRP3 inflammasome can be activated by different stimuli, including changes in cell volume and exposure to either molecules produced by damaged cells or toxins from bacteria. However, the precise mechanism through which the NLRP3 becomes activated in response to these stimuli was not clear. The exit of chloride ions from immune cells is known to activate the NLRP3 inflammasome. Chloride ions exit the cell through proteins called anion channels, including volume-regulated anion channels (VRACs), which respond to changes in cell volume. Green et al. have found that, in immune cells from mice grown in the lab called macrophages, VRACs are the only chloride channels involved in activating the NLRP3 inflammasome when the cell’s volume changes. However, when the macrophages are exposed to molecules produced by damaged cells or toxins from bacteria, Green et al. discovered that other previously unidentified chloride channels are involved in activating the NLRP3 inflammasome. These results suggest that it might be possible to develop drugs to prevent the activation of the NLRP3 inflammasome that selectively target specific sets of chloride channels depending on which stimuli are causing the inflammation. Such a selective approach would minimise the side effects associated with drugs that generically suppress all NLRP3 activity by directly binding to NLRP3 itself. Ultimately, this may help guide the development of new, targeted anti-inflammatory drugs that can help treat the symptoms of a variety of diseases in humans.