Multiple Cathepsins Promote Pro-IL-1β Synthesis and NLRP3-Mediated IL-1β Activation.
Multiple Cathepsins Promote Pro-IL-1β Synthesis and NLRP3-Mediated IL-1β Activation.
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DOI：
10.4049/jimmunol.1500509
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发表时间：
2015-08-15
期刊：
影响因子：
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通讯作者：
Rock KL
中科院分区：
文献类型：
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作者：
Orlowski GM;Colbert JD;Sharma S;Bogyo M;Robertson SA;Rock KL
无菌颗粒诱导强烈的炎症反应，这些炎症反应是矽肺、痛风和动脉粥样硬化等疾病发病机制的基础。介导这种应答的关键细胞因子是IL-1β。通过无菌颗粒产生生物活性IL-1β是由NLRP 3炎性体介导的，尽管这究竟是如何发生的还没有完全解决。先前的研究已经发现，组织蛋白酶B抑制剂Ca 074 Me抑制这种反应，支持这样一种模型，即摄入的颗粒破坏溶酶体并将组织蛋白酶B释放到胞质溶胶中，以某种方式激活NLRP 3。然而，组织蛋白酶B缺陷型巨噬细胞在颗粒诱导的IL-1β产生中没有缺陷的报道质疑了组织蛋白酶B的参与。在此，我们通过评估组织蛋白酶B、L、C、S和X单一或多重缺陷的小鼠巨噬细胞中IL-1β的产生，检验了多个冗余组织蛋白酶（不仅仅是组织蛋白酶B）介导这一过程的假设。使用基于活性的探针，我们测量活细胞中的特异性组织蛋白酶活性，记录组织蛋白酶缺陷细胞中的代偿性变化，并分析Ca 074 Me的剂量依赖性组织蛋白酶抑制谱及其对颗粒诱导的IL-1β分泌的抑制。此外，我们评估内源性组织蛋白酶抑制剂，半胱氨酸蛋白酶抑制剂C和B。令人惊讶的是，我们发现多个冗余的组织蛋白酶，由Ca 074 Me和半胱氨酸蛋白酶抑制剂抑制，促进pro-IL-1β的合成，我们提供了第一个证据，组织蛋白酶X在非颗粒NLRP 3激活中发挥非冗余的作用。最后，我们发现组织蛋白酶抑制剂选择性地阻断颗粒诱导的NLRP 3激活，而不依赖于抑制pro-IL-1β的合成。总之，我们证明了小分子和内源性组织蛋白酶抑制剂都抑制颗粒诱导的IL-1β分泌，这暗示了多种组织蛋白酶在IL-1β前体合成和NLRP 3活化中的作用。
Sterile particles induce robust inflammatory responses that underlie the pathogenesis of diseases like silicosis, gout and atherosclerosis. A key cytokine mediating this response is IL-1β. The generation of bioactive IL-1β by sterile particles is mediated by the NLRP3 inflammasome, although exactly how this occurs is incompletely resolved. Prior studies have found that the cathepsin B inhibitor, Ca074Me, suppresses this response, supporting a model whereby ingested particles disrupt lysosomes and release cathepsin B into the cytosol, somehow activating NLRP3. However, reports that cathepsin B-deficient macrophages have no defect in particle-induced IL-1β generation have questioned cathepsin B’s involvement. Here, we examine the hypothesis that multiple redundant cathepsins (not just cathepsin B) mediate this process by evaluating IL-1β generation in murine macrophages, singly or multiply deficient in cathepsins B, L, C, S and X. Using an activity-based probe, we measure specific cathepsin activity in living cells, documenting compensatory changes in cathepsin-deficient cells, and Ca074Me’s dose-dependent cathepsin inhibition profile is analyzed in parallel with its suppression of particle-induced IL-1β secretion. Also, we evaluate endogenous cathepsin inhibitors, cystatins C and B. Surprisingly, we find that multiple redundant cathepsins, inhibited by Ca074Me and cystatins, promote pro-IL-1β synthesis, and we provide the first evidence that cathepsin X plays a non-redundant role in non-particulate NLRP3 activation. Finally, we find cathepsin inhibitors selectively block particle-induced NLRP3 activation, independently of suppressing pro-IL-1β synthesis. Altogether, we demonstrate that both small molecule and endogenous cathepsin inhibitors suppress particle-induced IL-1β secretion, implicating roles for multiple cathepsins in both pro-IL-1β synthesis and NLRP3 activation.