Ranjan Ravi, Deng Jing, Chung Sangwoon, Lee Yong Gyu, Park Gye Young, Xiao Lei, Joo Myungsoo, Christman John William, Karpurapu Manjula
Department of Medicine and Section of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois, Chicago, Ill., USA.
J Innate Immun. 2014;6(6):754-64. doi: 10.1159/000362647. Epub 2014 Jun 20.
The role of the transcription factor nuclear factor of activated T cells (NFAT) was initially identified in T and B cell gene expression, but its role in regulating gene expression in macrophages during sepsis is not known. Our data show that NFATc3 regulates expression of inducible nitric oxide synthase (iNOS) in macrophages stimulated with lipopolysaccharide. Selective inhibition of NFAT by cyclosporine A and a competitive peptide inhibitor 11R-VIVIT inhibited endotoxin-induced expression of iNOS and nitric oxide (NO) release. Macrophages from NFATc3 knockout (KO) mice show reduced iNOS expression and NO release and attenuated bactericidal activity. Gel shift and chromatin immunoprecipitation assays show that endotoxin challenge increases NFATc3 binding to the iNOS promoter, resulting in transcriptional activation of iNOS. The binding of NFATc3 to the iNOS promoter is abolished by NFAT inhibitors. NFATc3 KO mice subjected to sepsis show that NFATc3 is necessary for bacterial clearance in mouse lungs during sepsis. Our study demonstrates for the first time that NFATc3 is necessary for macrophage iNOS expression during sepsis, which is essential for containment of bacterial infections.
转录因子活化T细胞核因子（NFAT）的作用最初是在T细胞和B细胞基因表达中被发现的，但其在脓毒症期间巨噬细胞基因表达调控中的作用尚不清楚。我们的数据表明，NFATc3调节脂多糖刺激的巨噬细胞中诱导型一氧化氮合酶（iNOS）的表达。环孢素A和竞争性肽抑制剂11R-VIVIT对NFAT的选择性抑制作用，抑制了内毒素诱导的iNOS表达和一氧化氮（NO）释放。NFATc3基因敲除（KO）小鼠的巨噬细胞显示iNOS表达降低、NO释放减少且杀菌活性减弱。凝胶迁移和染色质免疫沉淀试验表明，内毒素刺激增加了NFATc3与iNOS启动子的结合，导致iNOS转录激活。NFAT抑制剂可消除NFATc3与iNOS启动子的结合。脓毒症的NFATc3 KO小鼠表明，NFATc3是脓毒症期间小鼠肺部细菌清除所必需的。我们的研究首次证明，NFATc3是脓毒症期间巨噬细胞iNOS表达所必需的，这对于控制细菌感染至关重要。
