曲尼司特在调控 NLRP3 泛素化、血管炎症和动脉粥样硬化中的新作用

Background Aberrant activation of the NLRP3 (nucleotide-binding oligomerization domain, leucine-rich repeat-containing receptor family pyrin domain-containing 3) inflammasome is thought to play a causative role in atherosclerosis. NLRP3 is kept in an inactive ubiquitinated state to avoid unwanted NLRP3 inflammasome activation. This study aimed to test the hypothesis that pharmacologic manipulating of NLRP3 ubiquitination blunts the assembly and activation of the NLRP3 inflammasome and protects against vascular inflammation and atherosclerosis. Since genetic studies yielded mixed results about the role for this inflammasome in atherosclerosis in low-density lipoprotein receptor- or apolipoprotein E-deficient mice, this study attempted to clarify the discrepancy with the pharmacologic approach using both models. Methods and Results We provided the first evidence demonstrating that tranilast facilitates NLRP3 ubiquitination. We showed that tranilast restricted NLRP3 oligomerization and inhibited NLRP3 inflammasome assembly. Tranilast markedly suppressed NLRP3 inflammasome activation in low-density lipoprotein receptor- and apolipoprotein E-deficient macrophages. Through reconstitution of the NLRP3 inflammasome in human embryonic kidney 293T cells, we found that tranilast directly limited NLRP3 inflammasome activation. By adopting different regimens for tranilast treatment of low-density lipoprotein receptor- and apolipoprotein E-deficient mice, we demonstrated that tranilast blunted the initiation and progression of atherosclerosis. Mice receiving tranilast displayed a significant reduction in atherosclerotic lesion size, concomitant with a pronounced decline in macrophage content and expression of inflammatory molecules in the plaques compared with the control group. Moreover, tranilast treatment of mice substantially hindered the expression and activation of the NLRP3 inflammasome in the atherosclerotic lesions. Conclusions Tranilast potently enhances NLRP3 ubiquitination, blunts the assembly and activation of the NLRP3 inflammasome, and ameliorates vascular inflammation and atherosclerosis in both low-density lipoprotein receptor- and apolipoprotein E-deficient mice.

背景：NLRP3（核苷酸结合寡聚化结构域、富含亮氨酸重复序列的受体家族含pyrin 结构域蛋白 3）炎性小体的异常激活被认为在动脉粥样硬化中起因果作用。NLRP3 以无活性的泛素化状态存在，以避免不必要的 NLRP3 炎性小体激活。本研究旨在验证以下假说：通过药理学手段操纵 NLRP3 泛素化，可减轻 NLRP3 炎性小体的组装和激活，并预防血管炎症和动脉粥样硬化。由于遗传研究对低密度脂蛋白受体或载脂蛋白 E 缺陷小鼠中这种炎性小体在动脉粥样硬化中的作用得出了混合结果，因此本研究试图通过药理学方法来阐明这一差异，同时使用两种模型。

方法和结果：我们首次提供了证据表明曲尼司特促进 NLRP3 泛素化。我们表明，曲尼司特限制 NLRP3 寡聚化并抑制 NLRP3 炎性小体的组装。曲尼司特显著抑制低密度脂蛋白受体和载脂蛋白 E 缺陷的巨噬细胞中 NLRP3 炎性小体的激活。通过在人胚肾 293T 细胞中重建 NLRP3 炎性小体，我们发现曲尼司特直接限制 NLRP3 炎性小体的激活。通过采用不同的曲尼司特治疗方案治疗低密度脂蛋白受体和载脂蛋白 E 缺陷的小鼠，我们证明曲尼司特减弱了动脉粥样硬化的起始和进展。与对照组相比，接受曲尼司特治疗的小鼠的动脉粥样硬化病变明显缩小，斑块中巨噬细胞含量和炎症分子的表达也明显降低。此外，曲尼司特治疗显著抑制了动脉粥样硬化病变中 NLRP3 炎性小体的表达和激活。

结论：曲尼司特可有效增强 NLRP3 泛素化，抑制 NLRP3 炎性小体的组装和激活，从而改善低密度脂蛋白受体和载脂蛋白 E 缺陷小鼠的血管炎症和动脉粥样硬化。