Molecular regulatory mechanisms of NO analyzed by using nitronyl nitroxide

一氧化氮（NO）已被认为参与多种疾病的发病机制，包括感染、炎症性疾病和癌症。我们已经证实，在癌前组织和癌症组织中，包括特发性肺纤维化和人类肺癌，以及吸烟者的尿液中，存在硝酸修饰的核酸（例如，8-硝基鸟嘌呤和8-硝基鸟嘌呤）。在这项研究中，我们发现在炎症细胞因子刺激的巨噬细胞中形成了新的硝化环核苷酸，8-硝基鸟嘌呤-3′，5′-环单磷酸（8-硝基-c GMP）。8-硝基cGMP具有cGMP依赖性蛋白激酶激活电位和独立于cGMP活性的独特信号功能。重要的是一种新的翻译后修饰（8-硝基- cgmp加合物形成），被称为s -胍基化。例如，氧化还原传感器信号蛋白Keap 1似乎受到8-硝基- cgmp的调节，通过对Keap 1高度亲核的Cys巯基进行s -胍基化，从而诱导应激适应反应信号。本研究揭示了8-硝基cGMP是NO的第二信使，为NO和cGMP信号转导的病理生理和化学生物学研究开辟了新的领域。

Nitric oxide (NO) has been suggested to be involved in the pathogenesis of various diseases, including infections, inflammatory diseases, and cancer. We have demonstrated the occurrence of nitratively modified nucleic acids (e.g., 8-nitroguanosine and 8-nitroguanine) in precancerous and cancer tissues, including idiopathic pulmonary fibrosis and human lung cancer, and in urine of smokers. In this study, we identified the formation of novel nitrated cyclic nucleotide, 8-nitroguano sine-3', 5'-cyclic monophosphate (8-nitro-c GMP), in macrophages stimulated with inflammatory cytokine. 8-Nitro-cGMP possesses cGMP-dependent protein kinase-activating potential and unique signal functions independent of cGMP activity. Of great importance is a novel post-translational modification (8-thioalkoxy-cGMP adduct formation) of proteins induced by 8-nitro-cGMP, coined S-guanylation. For example, a redox-sensor signal protein Keap 1 appears to be regulated by 8-nitro-cGMP, via S-guanylation of highly nucleophilic Cys sulfhydrils of Keap 1, leading to the induction of stress adaptive response signals. This study revealed 8-nitro-cGMP to be asecond messenger of NO and shed light on new areas of pathophysiology and chemical biology of signal transduction by NO and cGMP.