Laboratory of Immunobiology, Department of Marine Life Sciences, Jeju National University, Jeju 690-756, Republic of Korea.
Food Chem Toxicol. 2012 Dec;50(12):4270-6. doi: 10.1016/j.fct.2012.08.041. Epub 2012 Sep 10.
Since the anti-inflammatory effect of caffeine is unclear in microglial cells, we performed whether caffeine attenuates the expression of pro-inflammatory mediators in lipopolysaccharide (LPS)-stimulated BV2 microglial cells. Caffeine substantially suppressed the LPS-induced pro-inflammatory mediators nitric oxide (NO), prostaglandin E(2) (PGE(2)) and tumor necrosis factor-α (TNF-α) in BV2 microglial cells. These effects resulted from the inhibition of their regulatory genes inducible NO synthase (iNOS), cycloxygenase-2 (COX-2) and TNF-α. In addition, caffeine significantly decreased LPS-induced DNA-binding activity of nuclear factor-κB (NF-κB) by suppressing the nuclear translocation of p50 and p65 subunits. A specific NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC), attenuated the LPS-induced expression of iNOS, COX-2 and TNF-α genes. In addition, we elucidated that inhibition of Akt phosphorylation plays a crucial role in caffeine-mediated NF-κB regulation in LPS-stimulated BV2 microglial cells. Caffeine also attenuated the LPS-induced phosphorylation of extracellular signal-regulated kinase (ERK) and a specific inhibitor of ERK, PD98059, subsequently downregulated the expression of the pro-inflammatory genes iNOS, COX-2 and TNF-α. Taken together, our data indicate that caffeine suppresses the generation of pro-inflammatory mediators, such as NO, PGE(2) and TNF-α as well as their regulatory genes in LPS-stimulated BV2 microglial cells by inhibiting Akt-dependent NF-κB activation and the ERK signaling pathway.
由于咖啡因在小胶质细胞中的抗炎作用尚不清楚，我们研究了咖啡因是否能减弱脂多糖（LPS）刺激的 BV2 小胶质细胞中促炎介质的表达。咖啡因能显著抑制 LPS 诱导的 BV2 小胶质细胞中促炎介质一氧化氮（NO）、前列腺素 E2（PGE2）和肿瘤坏死因子-α（TNF-α）的表达。这些作用是通过抑制其调节基因诱导型一氧化氮合酶（iNOS）、环氧化酶-2（COX-2）和 TNF-α 实现的。此外，咖啡因通过抑制 p50 和 p65 亚基的核转位，显著降低 LPS 诱导的核因子-κB（NF-κB）的 DNA 结合活性。一种特定的 NF-κB 抑制剂吡咯烷二硫代氨基甲酸盐（PDTC）减弱了 LPS 诱导的 iNOS、COX-2 和 TNF-α 基因的表达。此外，我们阐明了抑制 Akt 磷酸化在 LPS 刺激的 BV2 小胶质细胞中咖啡因介导的 NF-κB 调节中起着关键作用。咖啡因还减弱了 LPS 诱导的细胞外信号调节激酶（ERK）的磷酸化，ERK 的一种特异性抑制剂 PD98059，随后下调了促炎基因 iNOS、COX-2 和 TNF-α 的表达。总之，我们的数据表明，咖啡因通过抑制 Akt 依赖性 NF-κB 激活和 ERK 信号通路，抑制 LPS 刺激的 BV2 小胶质细胞中促炎介质如 NO、PGE2 和 TNF-α 以及其调节基因的产生，从而抑制炎症反应。
