Lipopolysaccharide-induced expression of interferon-β mediates the timing of inducible nitric-oxide synthase induction in RAW 264.7 macrophages
Lipopolysaccharide-induced expression of interferon-β mediates the timing of inducible nitric-oxide synthase induction in RAW 264.7 macrophages
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DOI：
10.1074/jbc.m106639200
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发表时间：
2001-12-21
影响因子：
4.8
通讯作者：
Ignarro, LJ
中科院分区：
文献类型：
--
作者：
Jacobs, AT;Ignarro, LJ
巨噬细胞产生一氧化氮被认为是宿主抵抗微生物病原体和肿瘤细胞的防御机制。最近的报告表明干扰素-α/β（IFN-alpha/β）是一种对诱导小鼠iNOS至关重要的自分泌/旁分泌信号。在这份报告中，我们系统地研究了IFN-β在诱导小鼠巨噬细胞系RAW 264.7中诱导型一氧化氮合酶的作用。首先，我们证明了IFN-β的表达是高度上调的，并且是响应于脂多糖（LPS）而分泌的。用LPS处理RAW巨噬细胞导致STAT-1在酪氨酸残基701（Tyr-701）和丝氨酸残基727（Ser-727）上的时间依赖性磷酸化，这与内源性IFN-β表达的时间一致。LPS也以类似的动力学诱导干扰素调节因子-1的表达。我们进一步证明了外源性IFN-β加速LPS对iNOS的诱导。在转录、蛋白质表达和NO形成水平上观察到iNOS诱导的加速。因此，我们建议巨噬细胞的细胞因子环境可能决定一氧化氮产生的速率和幅度，从而调节对病原体挑战的细胞毒性反应。
The production of nitric oxide by macrophages has been implicated as a host defense mechanism against microbial pathogens and tumor cells. Recent reports have implicated interferon-alpha/beta (IFN-alpha/beta) as an autocrine/paracrine signal critical for the induction of murine iNOS. In this report we have systematically investigated the role of IFN-beta in the induction of iNOS in the murine macrophage cell line, RAW 264.7. First, we demonstrate that IFN-beta expression is highly up-regulated, and is secreted in response to lipopolysaccharide (LPS). Treatment of RAW macrophages with LPS results in a time-dependent phosphorylation of STAT-1 on both tyrosine residue 701 (Tyr-701) and serine residue 727 (Ser-727) that is consistent with the timing of endogenous IFN-beta expression. LPS also induces interferon regulatory factor-1 expression with similar kinetics. We further demonstrate that exogenous IFN-beta accelerates the induction of iNOS by LPS. The acceleration of iNOS induction is observed at the levels of transcription, protein expression, and NO formation. Accordingly, we propose that the cytokine environment of macrophages may determine the rate and magnitude of nitric oxide production, thereby regulating the cytotoxic response to pathogen challenge.