Macrophages require constitutive NF-κB activation to maintain A1 expression and mitochondrial homeostasis
Macrophages require constitutive NF-κB activation to maintain A1 expression and mitochondrial homeostasis
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DOI：
10.1128/mcb.20.23.8855-8865.2000
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发表时间：
2000-12-01
影响因子：
5.3
通讯作者：
Pope, RM
中科院分区：
文献类型：
--
作者：
Pagliari, LJ;Perlman, H;Pope, RM
NF-κ B是巨噬细胞炎症反应的关键介质，但其在调节巨噬细胞存活中的作用尚未阐明。在这里，我们证明了组成性NF-κ B活化是巨噬细胞存活所必需的。用吡咯烷二硫代氨基甲酸酯阻断NF-κ B的组成性激活或I κ B α的表达诱导巨噬细胞样RAW 264.7细胞和原代人巨噬细胞的凋亡。这种凋亡是独立的额外的死亡诱导刺激，包括Fas连接。抑制NF-κ B活化诱导线粒体跨膜电位（Delta Psi（m））和DNA片段化的时间依赖性损失。检查引发剂半胱天冬酶揭示了半胱天冬酶9的切割，但不半胱天冬酶8或效应半胱天冬酶3。加入一般的半胱天冬酶抑制剂，z-VAD. fetamine，或特异性半胱天冬酶9抑制剂减少DNA片段化，但对Δ Psi（m）塌陷没有影响，表明该事件是半胱天冬酶独立的。为了确定导致线粒体功能障碍的途径，对Bcl-2家族成员的分析确定，在Δ Psi（m）损失之前，只有A1 mRNA水平降低，并且A1的异位表达在NF-κ B失活后保护细胞免于死亡。这些数据表明，抑制NF-κ B在巨噬细胞启动caspase 3非依赖性凋亡通过减少A1的表达和线粒体功能障碍。因此，组成性NF-κ B活化通过维持A1表达和线粒体稳态来保护巨噬细胞活力。
NF-kappaB is a critical mediator of macrophage inflammatory responses, but its role in regulating macrophage survival has yet to be elucidated. Here, we demonstrate that constitutive NF-kappaB activation is essential for macrophage survival. Blocking the constitutive activation of NF-kappaB with pyrrolidine dithiocarbamate or expression of I kappaB alpha induced apoptosis in macrophagelike RAW 264.7 cells and primary human macrophages. This apoptosis was independent of additional death-inducing stimuli, including Fas ligation. Suppression of NF-kappaB activation induced a time-dependent loss of mitochondrial transmembrane potential (Delta Psi (m)) and DNA fragmentation. Examination of initiator caspases revealed the cleavage of caspase 9 but not caspase 8 or the effector caspase 3. Addition of a general caspase inhibitor, z-VAD.fmk, or a specific caspase 9 inhibitor reduced DNA fragmentation but had no effect on Delta Psi (m) collapse, indicating this event was caspase independent. To determine the pathway leading to mitochondrial dysfunction, analysis of Bcl-2 family members established that only A1 mRNA levels were reduced prior to Delta Psi (m) loss and that ectopic expression of A1 protected against cell death following inactivation of NF-kappaB. These data suggest that inhibition of NF-kappaB in macrophages initiates caspase 3-independent apoptosis through reduced A1 expression and mitochondrial dysfunction. Thus, constitutive NF-kappaB activation preserves macrophage viability by maintaining A1 expression and mitochondrial homeostasis.