Department of Biological Science, Graduate School of Science, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan.
Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA; Department of Environmental Medicine and Molecular Toxicology, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8575, Japan.
Biochem Biophys Res Commun. 2019 Mar 26;511(1):141-147. doi: 10.1016/j.bbrc.2019.01.138. Epub 2019 Feb 14.
We previously reported that 8-nitroguanosine 3',5'-cyclic monophosphate (8-nitro-cGMP) is endogenously produced via nitric oxide/reactive oxygen species signaling pathways and it reacts with protein thiol residues to add cGMP structure to proteins through S-guanylation. S-Guanylation occurs on synaptosomal-associated protein 25 (SNAP-25), which is a part of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex that regulates exocytosis. However, the biological relevance of 8-nitro-cGMP in the nervous system remains unclear. Here, we investigated the effects of intracerebroventricular (icv) infusion of 8-nitro-cGMP on mouse brain functions. The results of an open-field test and fear-conditioning task revealed that icv infusion of 8-nitro-cGMP decreased the vertical activity and context-dependent fear memory of mice, which are both associated with the hippocampus. Immunohistochemical analysis revealed increased c-Fos-positive cells in the dentate gyrus in 8-nitro-cGMP-infused mice. Further, biochemical analyses showed that icv infusion of 8-nitro-cGMP increased S-guanylated proteins including SNAP-25 and SNARE complex formation as well as decreased complexes containing complexin, which regulates exocytosis by binding to the SNARE complex, in the hippocampus. These findings suggest that accumulation of 8-nitro-cGMP in the hippocampus affects its functions, including memory, via S-guanylation of hippocampal proteins such as SNAP-25.
我们之前报道过，8-硝鸟嘌呤核苷 3'，5'-环单磷酸（8-nitro-cGMP）通过一氧化氮/活性氧信号通路内源性产生，它与蛋白质巯基残基反应，通过 S-鸟苷化将 cGMP 结构添加到蛋白质中。S-鸟苷化发生在突触相关蛋白 25（SNAP-25）上，它是可溶性 N-乙基马来酰亚胺敏感因子附着蛋白受体（SNARE）复合物的一部分，调节胞吐作用。然而，8-nitro-cGMP 在神经系统中的生物学相关性尚不清楚。在这里，我们研究了脑室（icv）输注 8-nitro-cGMP 对小鼠大脑功能的影响。旷场试验和恐惧条件反射任务的结果表明，脑室输注 8-nitro-cGMP 降低了小鼠的垂直活动和上下文相关的恐惧记忆，这两者都与海马体有关。免疫组织化学分析显示，8-nitro-cGMP 输注小鼠的齿状回中 c-Fos 阳性细胞增多。此外，生化分析表明，脑室输注 8-nitro-cGMP 增加了 S-鸟苷化蛋白，包括 SNAP-25 和 SNARE 复合物形成，同时减少了含有复合蛋白的复合物，复合蛋白通过与 SNARE 复合物结合来调节胞吐作用，在海马体中。这些发现表明，8-nitro-cGMP 在海马体中的积累通过 S-鸟苷化海马体蛋白，如 SNAP-25，影响其功能，包括记忆。
