Inhibition of AIF-1 expression by constitutive siRNA expression reduces macrophage migration, proliferation, and signal transduction initiated by atherogenic stimuli
Inhibition of AIF-1 expression by constitutive siRNA expression reduces macrophage migration, proliferation, and signal transduction initiated by atherogenic stimuli
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DOI：
10.1152/ajpcell.00381.2005
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发表时间：
2006-04-01
影响因子：
5.5
通讯作者：
Autieri, MV
中科院分区：
文献类型：
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作者：
Tian, Y;Kelemen, SE;Autieri, MV
同种异体移植物炎症因子-1(AIF-1)是一种胞浆内钙结合的炎症反应支架蛋白。一些研究报道了激活的巨噬细胞中AIF-1的表达增加，并暗示AIF-1是激活的巨噬细胞的标志。然而，AIF-1在巨噬细胞中的功能及其参与巨噬细胞活化的机制目前尚不清楚。免疫组织化学分析显示AIF-1与CD68阳性巨噬细胞在动脉粥样硬化的冠状动脉中共表达。随后的实验旨在确定AIF-1在巨噬细胞对致动脉粥样硬化刺激的反应中的激活作用。氧化型低密度脂蛋白刺激人和小鼠巨噬细胞后，AIF-1的表达显著高于基础水平。稳定表达AIF-1小干扰RNA(SiRNA)的巨噬细胞AIF-1蛋白表达减少79%，巨噬细胞增殖减少52%(P<；0.01)。抑制细胞增殖不是由于诱导了细胞凋亡。未下调AIF-1表达的序列对细胞增殖没有影响。AIF-1 siRNA的表达使巨噬细胞迁移减少60%(P<；0.01)。腺病毒表达AIF-1可恢复siRNA表达的巨噬细胞的增殖和迁移(P分别为0.001和0.005)，提示AIF-1的表达与巨噬细胞的活化密切相关。氧化型低密度脂蛋白刺激后，siRNA巨噬细胞Akt、p44/42MAPK和p38蛋白的磷酸化水平显著降低(P<；0.05)。在T淋巴细胞条件培养液刺激的siRNA巨噬细胞中，p38激酶的磷酸化被显著抑制(P<；0.05)。这些数据表明，AIF-1介导了动脉粥样硬化启动的信号传递和巨噬细胞的激活。
Allograft inflammatory factor-1 ( AIF-1) is a cytoplasmic, calcium-binding, inflammation-responsive scaffold protein. Several studies have reported increased AIF-1 expression in activated macrophages and have implicated AIF-1 as a marker of activated macrophages. However, the function of AIF-1 in macrophages and the mechanism whereby it participates in macrophage activation are unknown at this time. Immunohistochemical analysis colocalized AIF-1 expression with CD68-positive macrophages in atherosclerotic human coronary arteries. Subsequent experiments were designed to determine a role for AIF-1 in macrophage activation in response to atherogenic stimuli. Stimulation of human and murine macrophages with oxidized LDL significantly increased AIF-1 expression above basal levels. Stable transfection of AIF-1 small interfering RNA ( siRNA) in macrophages reduced AIF-1 protein expression by 79% and reduced macrophage proliferation by 52% ( P < 0.01). Inhibition of proliferation was not due to induction of apoptosis. Sequences that did not knock down AIF- 1 expression had no effect on proliferation. AIF-1 siRNA expression reduced macrophage migration by 60% ( P < 0.01). Both proliferation and migration of siRNA-expressing macrophages could be restored by adenoviral expression of AIF-1 ( P < 0.001 and 0.005, respectively), suggesting a tight association between AIF-1 expression and macrophage activation. Phosphorylation of Akt, p44/42 MAPK, and p38 kinase were significantly reduced in siRNA macrophages challenged with oxidized LDL ( P < 0.05). Phosphorylation of p38 kinase was significantly inhibited in siRNA macrophages stimulated with T lymphocyte conditioned medium ( P < 0.05). These data indicate that AIF-1 mediates atherogenesis-initiated signaling and activation of macrophages.