Interferon gamma and interleukin 4 stimulate prolonged expression of inducible nitric oxide synthase in human airway epithelium through synthesis of soluble mediators
Interferon gamma and interleukin 4 stimulate prolonged expression of inducible nitric oxide synthase in human airway epithelium through synthesis of soluble mediators
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DOI：
10.1172/jci119598
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发表时间：
1997-08-15
影响因子：
15.9
通讯作者：
Erzurum, SC
中科院分区：
文献类型：
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作者：
Guo, FH;Uetani, K;Erzurum, SC
人呼吸道上皮细胞在体内持续表达诱导型一氧化氮合酶（iNOS），但维持其表达的机制尚不清楚。我们发现，IFN γ是足够的诱导的iNOS在原代人气道上皮细胞（HAEC）在体外，和IL-4增强IFN γ诱导的iNOS表达HAEC通过稳定的iNOS mRNA。IFN-γ/IL-4诱导的HAEC中iNOS表达在发病时延迟，并随着表达延长至1周。去除覆盖的培养基导致表达的损失，而条件培养基的转移诱导其他HAEC中的iNOS mRNA。IFN-γ和IL-4刺激激活HAEC中的STAT 1和STAT 6，但条件培养基转移到HAEC中产生的STAT 1激活水平甚至高于直接加入细胞因子所获得的水平。虽然诱导型一氧化氮合酶的细胞因子的诱导依赖于新的蛋白质的合成，条件培养基诱导的诱导型一氧化氮合酶在HAEC不是。此外，在细胞因子刺激后的不同时间从细胞中去除覆盖的培养基证明了对于诱导和维持iNOS重要的介质合成和/或分泌在细胞因子刺激后早期发生。总之，IFN γ/IL-4的组合，其天然存在于肺上皮衬里液中，通过产生可溶性介质和mRNA的稳定化导致人气道上皮中iNOS表达的维持。
Human respiratory epithelium expresses inducible nitric oxide synthase (iNOS) continuously in vivo, however mechanisms responsible for maintenance of expression are not known. We show that IFN gamma is sufficient for induction of iNOS in primary human airway epithelial cells (HAEC) in vitro, and IL-4 potentiates IFN gamma-induced iNOS expression in HAEC through stabilization of iNOS mRNA. IFN gamma/IL-4-induced iNOS expression in HAEC was delayed in onset and prolonged with expression up to 1 wk. Removal of overlying culture media resulted in loss of expression, while transfer of conditioned media induced iNOS mRNA in other HAEC. IFN gamma and IL-4 stimulation activated STAT1 and STAT6 in HAEC, but conditioned media transfer to HAEC produced even higher levels of STAT1 activation than achieved by direct addition of cytokines. Although cytokine induction of iNOS was dependent on new protein synthesis, conditioned media induction of iNOS in HAEC was not. Further, removal of overlying culture media from cells at different times after cytokine stimulation demonstrated that mediator synthesis and/or secretion important for induction and maintenance of iNOS occurs early after cytokine stimulation. In conclusion, a combination of IFN gamma/IL-4, which occurs naturally in the lung epithelial lining fluid, leads to maintenance of iNOS expression in human airway epithelium through production of soluble mediators and stabilization of mRNA.