Zhang Tian, Fang Zhujun, Linghu Ke-Gang, Liu Jingxin, Gan Lishe, Lin Ligen
State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Avenida da Universidade, Macau, China.
College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.
Br J Pharmacol. 2020 Oct;177(20):4645-4665. doi: 10.1111/bph.15215. Epub 2020 Aug 20.
IL-1β produced by macrophages via the NOD-, LRR- and pyrin domain-containing 3 (NLRP3) inflammasome, mediates the inflammatory crosstalk between macrophages and adipocytes. In our previous study, (16S,20S,24R)-12β-acetoxy-16,23-epoxy-24,25-dihydroxy-3β-(β-D-xylopyranosyloxy)-9,19-cyclolanost-22(23)-ene (AEDC), a cycloartane triterpenoid isolated from Actaea vaginata (Ranunculaceae), was found to possess anti-inflammatory effect on LPS-treated RAW264.7 macrophages. This study was designed to investigate whether AEDC modulates macrophage-adipocyte crosstalk to alleviate adipose tissue inflammation.
The anti-inflammatory effect of AEDC was evaluated on LPS plus ATP-induced THP-1 macrophages and C57BL/6J mice. The expression of autophagy-related and NLRP3 inflammasome complex proteins was analysed by western blots, immunofluorescence staining and co-immunoprecipitation. The pro-inflammatory cytokines levels were determined by ELISA kits. The adipose tissue inflammation was evaluated by histological analysis and immunohistochemical staining.
AEDC (5 and 10 μM) activated autophagy, which in turn suppressed the NLRP3 inflammasome activation and IL-1β secretion in THP-1 macrophages. AEDC increased the expression of SIRT3 deacetylase and enhanced its deacetylating activity to reverse mitochondrial dysfunction and activate AMP-activated protein kinase, which together induced autophagy. Moreover, AEDC (10 μM) attenuated macrophage conditioned medium-induced inflammatory responses in adipocytes and blocked THP-1 macrophages migration towards 3T3-L1 adipocytes. In inflammation mice, AEDC (5 and 20 mg·kg ) treatment reduced the levels of pro-inflammatory cytokines in serum and epididymal adipose tissue and reduced macrophage infiltration to alleviate adipose tissue inflammation.
AEDC attenuated the inflammatory crosstalk between macrophages and adipocytes through SIRT3-autophagy-mediated NLRP3 inflammasome inhibition, which might used for the treatment of adipose tissue inflammation-related metabolic disorders.
巨噬细胞通过含核苷酸结合寡聚化结构域样受体蛋白3（NLRP3）炎性小体产生的白细胞介素-1β（IL-1β）介导巨噬细胞与脂肪细胞之间的炎症串扰。在我们之前的研究中，从阴地乌头（毛茛科）中分离得到的环阿尔廷烷三萜（16S,20S,24R）-12β-乙酰氧基-16,23-环氧-24,25-二羟基-3β-（β-D-吡喃木糖氧基）-9,19-环羊毛甾-22（23）-烯（AEDC），被发现对脂多糖处理的RAW264.7巨噬细胞具有抗炎作用。本研究旨在探讨AEDC是否通过调节巨噬细胞-脂肪细胞串扰来减轻脂肪组织炎症。
在脂多糖加三磷酸腺苷诱导的THP-1巨噬细胞和C57BL/6J小鼠上评估AEDC的抗炎作用。通过蛋白质免疫印迹、免疫荧光染色和免疫共沉淀分析自噬相关蛋白和NLRP3炎性小体复合物蛋白的表达。用酶联免疫吸附测定试剂盒测定促炎细胞因子水平。通过组织学分析和免疫组织化学染色评估脂肪组织炎症。
AEDC（5和10 μM）激活自噬，进而抑制THP-1巨噬细胞中NLRP3炎性小体的激活和IL-1β的分泌。AEDC增加沉默信息调节因子3（SIRT3）去乙酰化酶的表达并增强其去乙酰化活性，以逆转线粒体功能障碍并激活腺苷酸活化蛋白激酶，共同诱导自噬。此外，AEDC（10 μM）减弱巨噬细胞条件培养基诱导的脂肪细胞炎症反应，并阻止THP-1巨噬细胞向3T3-L1脂肪细胞迁移。在炎症小鼠中，AEDC（5和20 mg·kg）治疗降低了血清和附睾脂肪组织中促炎细胞因子的水平，并减少巨噬细胞浸润以减轻脂肪组织炎症。
AEDC通过SIRT3-自噬介导的NLRP3炎性小体抑制减弱巨噬细胞与脂肪细胞之间的炎症串扰，这可能用于治疗与脂肪组织炎症相关的代谢紊乱。
