Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, 818 Tianyuan East Road, Nanjing, Jiangsu 211166, China.
Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, 818 Tianyuan East Road, Nanjing, Jiangsu 211166, China; Department of Pharmacology, Nanjing University of Chinese Medicine, 138 Xianlin Avenue, Nanjing, Jiangsu 210023, China.
Biochem Pharmacol. 2018 Apr;150:245-255. doi: 10.1016/j.bcp.2018.02.009. Epub 2018 Feb 13.
β2-Aderenergic receptor (β2AR) agonist, Salmeterol exhibits anti-inflammatory activities. However, the inhibitory effects of Salmeterol on inflammasome activation are elusive and the underlying mechanisms need to be explored. In this study, we established inflammatory model in primary bone marrow-derived macrophages (BMDM) from C57BL/6J mice and β-arrestin2 knockout (β-arrestin2) mice in vitro. In vivo study by LPS intraperitoneally (i.p.) in C57BL/6J mice was carried out to ascertain its roles in systemic inflammation. We found that Salmeterol (10 M-10 M) prevented the cleavage of caspase-1 and the activation of NLRP3 inflammasome, reduced the release of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in vitro. Blockade of adenosine3',5'cyclic monophosphate (cAMP)/protein kinase A (PKA) pathway with cAMP or PKA inhibitors inhibited anti-inflammatory effects of Salmeterol only at 10 M. Depletion of β-arrestin2 compromised the inhibitory effects of Salmeterol at both 10 M and 10 M. Salmeterol increased the interaction of β-arrestin2 and NLRP3. In vivo study showed that Salmeterol decreased the serum concentrations of pro-inflammatory cytokines IL-1β and TNF-α, blocked cleavage of caspase-1 and release of IL-1β in BMDM. These findings imply that Salmeterol at low concentrations (10 M-10 M) shows anti-inflammatory effect via inhibiting NLRP3 inflammasome. The underlying mechanisms is dosage-dependent: Salmeterol at 10 M shows anti-inflammatory effects through β-arrestin2 pathway, and 10 M Salmeterol inhibits inflammation via both classical G-protein coupled receptor (GPCR)/cAMP pathway and β-arrestin2 pathway. These results provide new ideas for the future treatment of systemic inflammation and other inflammatory diseases.
β2-肾上腺素能受体（β2AR）激动剂沙美特罗具有抗炎活性。然而，沙美特罗对炎症小体激活的抑制作用尚不清楚，需要进一步探索其潜在机制。在这项研究中，我们在体外建立了 C57BL/6J 小鼠原代骨髓来源巨噬细胞（BMDM）和β-arrestin2 敲除（β-arrestin2）小鼠的炎症模型，并通过 LPS 腹腔内（i.p.）注射 C57BL/6J 小鼠进行体内研究，以确定其在全身炎症中的作用。我们发现沙美特罗（10 M-10 M）可防止半胱天冬酶-1的切割和 NLRP3 炎症小体的激活，减少体外促炎细胞因子肿瘤坏死因子-α（TNF-α）和白细胞介素-1β（IL-1β）的释放。用 cAMP 或 PKA 抑制剂阻断腺苷 3'，5'环单磷酸（cAMP）/蛋白激酶 A（PKA）通路仅在 10 M 时抑制沙美特罗的抗炎作用。在 10 M 和 10 M 时，β-arrestin2 的耗竭削弱了沙美特罗的抑制作用。沙美特罗增加了β-arrestin2 和 NLRP3 的相互作用。体内研究表明，沙美特罗降低了血清中促炎细胞因子 IL-1β 和 TNF-α的浓度，阻断了 BMDM 中半胱天冬酶-1的切割和 IL-1β的释放。这些发现表明，低浓度（10 M-10 M）的沙美特罗通过抑制 NLRP3 炎症小体发挥抗炎作用。潜在机制是剂量依赖性的：10 M 的沙美特罗通过β-arrestin2 途径发挥抗炎作用，而 10 M 的沙美特罗通过经典 G 蛋白偶联受体（GPCR）/cAMP 途径和β-arrestin2 途径抑制炎症。这些结果为全身性炎症和其他炎症性疾病的未来治疗提供了新的思路。
