Environmental and Occupational Health Sciences Institute, Rutgers, The State University of New Jersey, Piscataway, New Jersey.
School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
Am J Physiol Lung Cell Mol Physiol. 2019 Nov 1;317(5):L539-L549. doi: 10.1152/ajplung.00506.2018. Epub 2019 Aug 14.
Surfactant protein-D (SP-D) is a regulator of pulmonary innate immunity whose oligomeric state can be altered through -nitrosylation to regulate its signaling function in macrophages. Here, we examined how nitrosylation of SP-D alters the phenotypic response of macrophages to stimuli both in vivo and in vitro. Bronchoalveolar lavage (BAL) from C57BL6/J and SP-D-overexpressing (SP-D OE) mice was incubated with RAW264.7 cells ± LPS. LPS induces the expression of the inflammatory genes and , which is reduced 10-fold by SP-D OE-BAL. -nitrosylation of the SP-D OE-BAL (SNO-SP-D OE-BAL) abrogated this inhibition. SNO-SP-D OE-BAL alone induced and expression. PCR array analysis of macrophages incubated with SP-D OE-BAL (±LPS) shows increased expression of repair genes, , , and , that was accentuated by LPS. LPS increases inflammatory gene expression, , , , and , which was accentuated by SNO-SP-D OE-BAL but inhibited by SP-D OE-BAL. The transcription factor NF-κB was identified as a target for SNO-SP-D by IPA, which was confirmed by Trans-AM ELISA in vitro. In vivo, SP-D overexpression increases the burden of infection in a model while increasing cellular recruitment. Expression of iNOS and the production of NO metabolites were significantly reduced in SP-D OE mice relative to C57BL6/J. Inflammatory gene expression was increased in infected C57BL6/J mice but decreased in SP-D OE. SP-D oligomeric structure was disrupted in C57BL6/J infected mice but unaltered within SP-D OE. Thus SP-D modulates macrophage phenotype and the balance of multimeric to trimeric SP-D is critical to this regulation.
表面活性蛋白-D（SP-D）是肺先天免疫的调节剂，其寡聚状态可以通过 - 亚硝化作用改变，以调节其在巨噬细胞中的信号功能。在这里，我们研究了 SP-D 的硝化如何改变巨噬细胞对体内和体外刺激的表型反应。用 RAW264.7 细胞孵育 C57BL6/J 和 SP-D 过表达（SP-D OE）小鼠的支气管肺泡灌洗液（BAL）±LPS。LPS 诱导炎症基因 和 的表达，而 SP-D OE-BAL 则将其减少 10 倍。SP-D OE-BAL 的 - 亚硝化（SNO-SP-D OE-BAL）消除了这种抑制作用。SNO-SP-D OE-BAL 单独诱导 和 的表达。用 SP-D OE-BAL（±LPS）孵育的巨噬细胞 PCR 阵列分析显示，修复基因 、 、 和 的表达增加，LPS 进一步增强了这种表达。LPS 增加炎症基因 、 、 、 和 的表达，SNO-SP-D OE-BAL 进一步增强了这种表达，但 SP-D OE-BAL 抑制了这种表达。IPA 鉴定出 NF-κB 是 SNO-SP-D 的一个靶标，体外 Trans-AM ELISA 也证实了这一点。在体内，SP-D 过表达增加了 模型中感染的负担，同时增加了细胞募集。与 C57BL6/J 相比，SP-D OE 小鼠的 iNOS 表达和 NO 代谢产物的产生明显减少。感染的 C57BL6/J 小鼠的炎症基因表达增加，但 SP-D OE 小鼠的表达减少。C57BL6/J 感染小鼠的 SP-D 寡聚结构被破坏，但 SP-D OE 中的结构不变。因此，SP-D 调节巨噬细胞表型，多聚体到三聚体 SP-D 的平衡对这种调节至关重要。
