Department of Physiology, Jeju National University School of Medicine, 66 Jejudaehakno, Jeju-si, Jeju-do 690-756, Republic of Korea.
Eur J Pharmacol. 2012 Sep 5;690(1-3):4-12. doi: 10.1016/j.ejphar.2012.05.041. Epub 2012 Jun 7.
Excessive microglial activation-mediated neurotoxicity has been implicated in playing a crucial role in the pathogenesis of stroke and neurodegenerative diseases. Therefore, much attention has been paid to therapeutic strategies aimed at suppressing neurotoxic microglial activation. The microglial regulatory mechanism of methyl lucidone, a cyclopentenedione isolated from the stem bark of Lindera erythrocarpa Makino, was investigated in the present study. Methyl lucidone treatment (0.1-10 μM) significantly inhibited lipopolysaccharide (LPS, 100 ng/ml, 24 h)-stimulated nitric oxide (NO) production in a dose-dependent manner in both primary cortical microglia and BV-2 cell line. Moreover, it strongly inhibited LPS-stimulated secretion of pro-inflammatory cytokines, such as interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α). Methyl lucidone treatment markedly induced down-regulation of LPS-induced nuclear translocation of nuclear factor κB (NF-κB) through preventing the degradation of the inhibitory protein IκBα. In addition, phosphorylation of Akt and mitogen-activated protein kinases (MAPKs) such as extracellular signal-regulated kinase (ERK) and p38 kinases were also suppressed by methyl lucidone. The cell viabilities of HT-22 neurons were significantly attenuated by treatment of the conditioned media containing neurotoxic secretary molecules from LPS-stimulated microglia. However, methyl lucidone significantly blocked neuronal cell death induced by microglial conditioned media. These neuroprotective effects of methyl lucidone were also confirmed in a neuron-microglia co-culture system using EGFP-transfected B35 neuroblastoma cell line. Taken together, these results suggest that methyl lucidone may have a neuroprotective potential via inhibition of neurotoxic microglial activation implicated in neurodegeneration.
过度的小胶质细胞激活介导的神经毒性被认为在中风和神经退行性疾病的发病机制中起着关键作用。因此，人们非常关注旨在抑制神经毒性小胶质细胞激活的治疗策略。本研究探讨了从黄瑞木茎皮中分离得到的环戊烯二酮甲基卢定酮对小胶质细胞的调节机制。结果表明，甲基卢定酮（0.1-10 μM）处理可显著抑制脂多糖（LPS，100ng/ml，24 小时）刺激的原代皮质小胶质细胞和 BV-2 细胞系一氧化氮（NO）的产生，呈剂量依赖性。此外，它强烈抑制 LPS 刺激的促炎细胞因子如白细胞介素 6（IL-6）和肿瘤坏死因子α（TNF-α）的分泌。甲基卢定酮处理可明显诱导核因子κB（NF-κB）的核易位下调，从而防止抑制蛋白 IκBα的降解。此外，甲基卢定酮还抑制了 Akt 和丝裂原活化蛋白激酶（MAPKs）如细胞外信号调节激酶（ERK）和 p38 激酶的磷酸化。含有 LPS 刺激小胶质细胞分泌的神经毒性分子的条件培养基处理 HT-22 神经元的细胞活力明显减弱，但甲基卢定酮显著阻断了小胶质细胞条件培养基诱导的神经元细胞死亡。在使用 EGFP 转染的 B35 神经母细胞瘤细胞系的神经元-小胶质细胞共培养系统中也证实了甲基卢定酮的这些神经保护作用。综上所述，这些结果表明，甲基卢定酮可能通过抑制与神经退行性变有关的神经毒性小胶质细胞激活而具有神经保护作用。
