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NLRP3炎症小体是一个多聚蛋白复合物,由NLRP3、ASC和Pro-caspase-1蛋白组成,可识别病原微生物和多种危险信号[1-2]。其活化后介导炎性细胞因子,如白细胞介素(IL)-1β、IL-18的成熟与分泌,在抗感染免疫和多种人类炎性相关疾病,如痛风、2型糖尿病、阿尔茨海默病等中发挥重要作用[3-4]。目前,NLRP3炎症小体相关炎性疾病的治疗策略主要针对NLRP3炎症小体活化后的产物如IL-1β,但此方法无法治疗NLRP3炎症小体活化后IL-18分泌和细胞焦亡导致的疾病,且易影响细胞其他生理功能,存在较多弊端[5]。靶向抑制NLRP3炎症小体活化成为治疗相关炎性疾病的新策略,多种NLRP3炎症小体抑制剂表现出良好效果[6-9],但还难以应用于临床。桑黄酮是具有抗炎抗氧化中草药桑枝中的主要活性成分,已被证实在神经炎症上有明显抑制作用[10-11],但其能否抑制NLRP3炎症小体活化并缓解相关炎性疾病有待证明。本文旨在探究桑黄酮对NLRP3炎症小体活化及其相关炎性疾病的作用。
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Western blotting及ELISA结果显示,桑黄酮可剂量依赖地抑制尼日利亚菌素诱导的Caspase-1(p20)表达及IL-1β的分泌(P < 0.01)(见图 1、表 1),但非炎症小体相关的细胞因子TNF-α和IL-6分泌差异无统计学意义(P>0.05)(见表 2)。
分组 n IL-1β t* P* mock 3 52.15±2.21 — — LPS 3 55.90±1.58 — — LPS+Nigericin 3 1 352.42±77.10 — — LPS+Nigericin+Mul(5 μmol/L) 3 921.34±38.80 8.65 < 0.01 LPS+Nigericin+Mul(10 μmol/L) 3 633.80±79.56 11.23 < 0.01 LPS+Nigericin+Mul(15 μmol/L) 3 289.15±2.67 23.87 < 0.01 *示与LPS+Nigericin组比较假设检验的结果 表 1 桑黄酮对Nigericin刺激的BMDM细胞IL-1β表达的影响(x±s;pg/mL)
分组 n TNF-α IL-6 表达水平 TNF-α t* 表达水平 TNF-α t* mock 3 79.49±7.95 — — 94.73±0.27 — — LPS 3 2 538.39±102.69 0.18 >0.05 1 065.18±90.27 0.66 >0.05 LPS+Nigericin 4 2 524.76±98.79 — — 1 025.40±70.43 — — LPS+Nigericin+Mul
(5 μmol/L)4 2 572.00±140.36 0.55 >0.05 1 016.42±50.67 0.21 >0.05 LPS+Nigericin+Mul
(10 μmol/L)4 2 409.76±176.91 1.14 >0.05 1 080.59±14.01 1.54 >0.05 LPS+Nigericin+Mul
(15 μmol/L)4 2 430.84±181.51 0.91 >0.05 1 072.95±99.90 0.78 >0.05 *示与LPS+Nigericin组比较假设检验的结果 表 2 桑黄酮对Nigericin刺激的BMDM细胞TNF-α和IL-6表达的影响(x±s;pg/mL)
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除Nigericin外,多种病原菌和危险信号均可引起NLRP3炎症小体活化如MSU、ATP等。结果显示桑黄酮明显抑制Nigericin、ATP及MSU三种经典的NLRP3炎症小体激动剂所诱导的Caspase-1(p20)表达及IL-1β分泌(P < 0.01)(见图 2、表 3)。
分组 n IL-1β t P mock
Mul(15 μmol/L)3
353.83±5.13
55.79±4.630.49 >0.05 LPS+Nigericin
LPS+Nigericin+Mul(15 μmol/L)3
31 265.48±81.23
165.96±5.9233.38* < 0.01* LPS+ATP
LPS+ATP+Mul(15 μmol/L)3
32 135.70±80.80
596.73±55.4527.20△ < 0.01△ LPS+MSU
LPS+MSU+Mul(15 μmol/L)3
31 663.46±80.84
257.73±49.1025.74# < 0.01# *示与LPS+Nigericin组比较假设检验的结果; △示与LPS+ATP组比较,#示与LPS+MSU组比较 表 3 桑黄酮对多种刺激剂活化的BMDM细胞IL-1β表达的影响(x±s;pg/mL)
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为了明确桑黄酮在人THP-1细胞中是否同样抑制NLRP3炎症小体的活化,利用Nigericin刺激分化后的人THP-1细胞进行实验,结果显示桑黄酮可以剂量依赖性地抑制Caspase-1(p20)表达及IL-1β分泌(P < 0.01)(见图 3、表 4)。
分组 n IL-1β t* P* mock 3 94.73±0.27 — — LPS 3 94.58±0.47 — — LPS+Nigericin 4 1 261.93±36.16 — — LPS+Nigericin+Mul(5 μmol/L) 4 953.23±21.24 14.72 < 0.01 LPS+Nigericin+Mul(10 μmol/L) 4 586.87±25.55 30.49 < 0.01 LPS+Nigericin+Mul(15 μmol/L) 4 245.95±0.90 56.17 < 0.01 *示与LPS+Nigericin组比较假设检验的结果 表 4 桑黄酮对Nigericin刺激的THP-1细胞IL-1β表达的影响(x±s;pg/mL)
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在小鼠感染性休克模型中进一步验证桑黄酮在动物水平上的作用,ELISA检测小鼠血清及腹腔灌洗液IL-1β及TNF-α表达水平,结果表明,与LPS组相比,LPS+Mul组小鼠血清及腹腔灌洗液中IL-1β分泌明显降低(P < 0.01),而TNF-α的水平差异无统计学意义(见表 5)。除此之外,观察LPS注射后84h内小鼠生存状态,并绘制生存曲线,结果显示LPS组小鼠14h开始死亡,36h小鼠死亡率达80%。而LPS+Mul组小鼠64h开始死亡,72h小鼠死亡率为40%(P < 0.01)(见图 4)。
分组 n 血清 腹腔灌洗液 IL-1β/(pg/mL) TNF-α/(pg/mL) IL-1β/(pg/mL) TNF-α/(pg/mL) PBS组 3 26.17±3.09 41.22±1.88 23.83±1.01 44.49±3.78 LPS组 6 275.18±69.85 190.74±14.03 527.63±65.73 85.82±13.08 LPS+Mul组 6 132.7±44.35** 177.47±10.61 288.70±88.18** 85.81±10.67 F — 23.96 191.21 52.16 16.92 P — < 0.01 < 0.01 < 0.01 < 0.01 MS组内 — 2 854.068 129.511 5 040.231 121.104 q检验:与LPS组比较** P < 0.01 表 5 桑黄酮对感染性休克小鼠血清及腹腔灌洗液IL-1β及TNF-α的影响(x±s)
桑黄酮抑制NLRP3炎症小体活化并缓解感染性休克的作用研究
Effect of mulberrin on inhibiting the activation of NLRP3 inflammasome and relieving infectious shock
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摘要:
目的探究桑枝提取物桑黄酮对NLRP3炎症小体活化的影响, 为相关炎性疾病的治疗提供新思路。 方法在细胞水平上, 使用Western blotting和ELISA方法, 检测小鼠骨髓来源的巨噬细胞(BMDM)和人THP-1细胞在尼日利亚菌素、单钠尿酸盐和腺嘌呤核苷三磷酸(ATP)3种刺激剂诱导下的半胱氨酸蛋白酶-1(Caspase-1)和白细胞介素(IL)-1β表达水平。在动物实验中, 构建脂多糖(LPS)诱导的感染性休克模型, 将实验小鼠分为安慰剂组、感染性休克组和桑黄酮干预组, 利用ELISA检测小鼠腹腔灌洗液及血清中IL-1β和肿瘤坏死因子-α(TNF-α)水平。 结果在BMDM和THP-1细胞中, 桑黄酮可以抑制尼日利亚菌素、单钠尿酸盐和ATP这3种炎症小体激动剂诱导的Caspase-1和IL-1β的加工和成熟(P < 0.01), 而对非炎症小体相关的细胞因子TNF-α的分泌无影响(P>0.05)。在动物实验中, 发现桑黄酮可以缓解LPS诱导的小鼠感染性休克(P < 0.01), 明显抑制LPS诱导的小鼠血清及腹腔液中IL-1β的表达(P < 0.01), 延长LPS造模后小鼠的存活时间(P < 0.01)。 结论桑黄酮作为一种中草药活性成分提取物, 可以在体外和体内抑制NLRP3炎症小体的活化, 为NLRP3相关疾病的治疗提供了实验依据。 Abstract:ObjectiveTo investigate the effect of mulberrin, a Chinese herbal extract, on NLRP3 inflammasome activation, and provide new insight for NLRP3-related disease. MethodsWestern blotting and ELISA were used to detect the expression level of caspase-1 and interleukin-1β of mouse bone marrow derived macrophages (BMDM) and human THP-1 cells induced by three agonists: Nigerian bacteriocin, monosodium urate and adenosine triphosphate (ATP).Mouse septic shock model induced by lipopolysaccharide (LPS) was constructed, and experimental mice were divided into placebo group, septic shock group and mulberrin treatment group.The levels of IL-1β and TNF-α in intraperitoneal lavage fluid and serum were detected by ELISA. ResultsIn vitro experiments, we found that the processing and maturation of caspase-1 and IL-1β induced by three classic inflammasome agonists (Nigericin, MSU and ATP) were inhibited by mulberrin in BMDM and THP-1 cells (P < 0.01).However, there was no obviously difference observed on the secretion of non-inflammasome-related cytokines, such as TNF-α (P>0.05).In vivo experiments, mulberrin treatment alleviated septic shock, significantly inhibited IL-1β expression in serum and intraperitoneal lavage fluid of mice, and prolonged the survival time of LPS-induced mice(P < 0.01). ConclusionsAs an active ingredient of Chinese herb extract, mulberrin can inhibit the NLRP3 inflammasome activation in vitro and in vivo.Our study provide experimental evidences for the treatment of NLRP3-related diseases. -
Key words:
- mulberrin /
- NLRP3 inflammasome /
- inflammasome-related diseases
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表 1 桑黄酮对Nigericin刺激的BMDM细胞IL-1β表达的影响(x±s;pg/mL)
分组 n IL-1β t* P* mock 3 52.15±2.21 — — LPS 3 55.90±1.58 — — LPS+Nigericin 3 1 352.42±77.10 — — LPS+Nigericin+Mul(5 μmol/L) 3 921.34±38.80 8.65 < 0.01 LPS+Nigericin+Mul(10 μmol/L) 3 633.80±79.56 11.23 < 0.01 LPS+Nigericin+Mul(15 μmol/L) 3 289.15±2.67 23.87 < 0.01 *示与LPS+Nigericin组比较假设检验的结果 表 2 桑黄酮对Nigericin刺激的BMDM细胞TNF-α和IL-6表达的影响(x±s;pg/mL)
分组 n TNF-α IL-6 表达水平 TNF-α t* 表达水平 TNF-α t* mock 3 79.49±7.95 — — 94.73±0.27 — — LPS 3 2 538.39±102.69 0.18 >0.05 1 065.18±90.27 0.66 >0.05 LPS+Nigericin 4 2 524.76±98.79 — — 1 025.40±70.43 — — LPS+Nigericin+Mul
(5 μmol/L)4 2 572.00±140.36 0.55 >0.05 1 016.42±50.67 0.21 >0.05 LPS+Nigericin+Mul
(10 μmol/L)4 2 409.76±176.91 1.14 >0.05 1 080.59±14.01 1.54 >0.05 LPS+Nigericin+Mul
(15 μmol/L)4 2 430.84±181.51 0.91 >0.05 1 072.95±99.90 0.78 >0.05 *示与LPS+Nigericin组比较假设检验的结果 表 3 桑黄酮对多种刺激剂活化的BMDM细胞IL-1β表达的影响(x±s;pg/mL)
分组 n IL-1β t P mock
Mul(15 μmol/L)3
353.83±5.13
55.79±4.630.49 >0.05 LPS+Nigericin
LPS+Nigericin+Mul(15 μmol/L)3
31 265.48±81.23
165.96±5.9233.38* < 0.01* LPS+ATP
LPS+ATP+Mul(15 μmol/L)3
32 135.70±80.80
596.73±55.4527.20△ < 0.01△ LPS+MSU
LPS+MSU+Mul(15 μmol/L)3
31 663.46±80.84
257.73±49.1025.74# < 0.01# *示与LPS+Nigericin组比较假设检验的结果; △示与LPS+ATP组比较,#示与LPS+MSU组比较 表 4 桑黄酮对Nigericin刺激的THP-1细胞IL-1β表达的影响(x±s;pg/mL)
分组 n IL-1β t* P* mock 3 94.73±0.27 — — LPS 3 94.58±0.47 — — LPS+Nigericin 4 1 261.93±36.16 — — LPS+Nigericin+Mul(5 μmol/L) 4 953.23±21.24 14.72 < 0.01 LPS+Nigericin+Mul(10 μmol/L) 4 586.87±25.55 30.49 < 0.01 LPS+Nigericin+Mul(15 μmol/L) 4 245.95±0.90 56.17 < 0.01 *示与LPS+Nigericin组比较假设检验的结果 表 5 桑黄酮对感染性休克小鼠血清及腹腔灌洗液IL-1β及TNF-α的影响(x±s)
分组 n 血清 腹腔灌洗液 IL-1β/(pg/mL) TNF-α/(pg/mL) IL-1β/(pg/mL) TNF-α/(pg/mL) PBS组 3 26.17±3.09 41.22±1.88 23.83±1.01 44.49±3.78 LPS组 6 275.18±69.85 190.74±14.03 527.63±65.73 85.82±13.08 LPS+Mul组 6 132.7±44.35** 177.47±10.61 288.70±88.18** 85.81±10.67 F — 23.96 191.21 52.16 16.92 P — < 0.01 < 0.01 < 0.01 < 0.01 MS组内 — 2 854.068 129.511 5 040.231 121.104 q检验:与LPS组比较** P < 0.01 -
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