Laboratory of Pathology, College of Korean Medicine, Daejeon University, Daejeon 300-716, Republic of Korea.
Natural Products Research Institute, Gyeonggi Institute of Science and Technology Promotion, Gyeonggi-do 443-270, Republic of Korea.
Life Sci. 2014 May 17;103(2):59-67. doi: 10.1016/j.lfs.2014.04.003. Epub 2014 Apr 13.
Microglia-mediated inflammation is associated with pathogenesis of various neuronal disorders. This study investigated inhibitory effects of pheophytin a (PP) and chlorophyll a (CP) on neuroinflammation and underlying cellular mechanisms in microglia cells.
BV2 murine microglia cells were stimulated by lipopolysaccharide (LPS, 100 ng/mL) and interferon (IFN)-γ (10 U/mL). The productions of nitric oxide (NO) and expressions of proinflammatory cytokines and chemokines were determined by ELISA and RT-PCR. Western blot and confocal microscopy were applied to analyze activation of transcription factors and mitogen activated protein kinase (MAPK).
PP and CP significantly reduced the levels of NO, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and chemokines including macrophage inhibitory protein (MIP)-1α, macrophage chemoattractant protein (MCP)-1 and IFN-γ inducible protein (IP)-10 in BV2 cells stimulated with LPS and IFN-γ (LI). The nuclear expression of p65 NF-κB was significantly suppressed, which was accompanied by reduced the levels of IFN-β, phospho-STAT-1, and interferon regulatory factor (IRF)-1. Activation of extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) but not p38 MAPK were prominently suppressed by PP and/or CP.
PP and CP may suppress inflammatory responses by inhibiting NF-κB activation and type I IFN signaling pathway. These result suggested that PP and CP have potential as anti-inflammatory agents for microglia-mediated neuroinflammatory disorders.
小胶质细胞介导的炎症与各种神经元疾病的发病机制有关。本研究探讨了叶啉 a（PP）和叶绿素 a（CP）对小胶质细胞神经炎症的抑制作用及其潜在的细胞机制。
用脂多糖（LPS，100ng/ml）和干扰素（IFN）-γ（10U/ml）刺激 BV2 小鼠小胶质细胞。通过 ELISA 和 RT-PCR 测定一氧化氮（NO）的产生和促炎细胞因子和趋化因子的表达。采用 Western blot 和共聚焦显微镜分析转录因子和丝裂原活化蛋白激酶（MAPK）的激活。
PP 和 CP 显著降低了 LPS 和 IFN-γ（LI）刺激的 BV2 细胞中 NO、肿瘤坏死因子（TNF）-α、白细胞介素（IL）-1β、IL-6 和趋化因子（MIP）-1α、单核细胞趋化蛋白（MCP）-1 和 IFN-γ诱导蛋白（IP）-10 的水平。核转录因子 p65 NF-κB 的表达明显受到抑制，同时 IFN-β、磷酸化 STAT-1 和干扰素调节因子（IRF）-1 的水平也降低。PP 和/或 CP 明显抑制细胞外信号调节激酶（ERK）和 c-Jun NH2-末端激酶（JNK）的激活，但不抑制 p38 MAPK。
PP 和 CP 可能通过抑制 NF-κB 激活和 I 型 IFN 信号通路来抑制炎症反应。这些结果表明，PP 和 CP 具有作为小胶质细胞介导的神经炎症疾病的抗炎剂的潜力。
