1 Centre for Biomedical Research (CBMR), University of Algarve , Faro, Portugal .
2 Department of Biomedical Sciences and Medicine, University of Algarve , Faro, Portugal .
Antioxid Redox Signal. 2018 Jan 1;28(1):15-30. doi: 10.1089/ars.2016.6858. Epub 2017 Aug 7.
Nitric oxide (NO) is involved in the upregulation of endogenous neurogenesis in the subventricular zone and in the hippocampus after injury. One of the main neurogenic pathways activated by NO is the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) pathway, downstream of the epidermal growth factor receptor. However, the mechanism by which NO stimulates cell proliferation through activation of the ERK/MAPK pathway remains unknown, although p21Ras seems to be one of the earliest targets of NO. Here, we aimed at studying the possible neurogenic action of NO by post-translational modification of p21Ras as a relevant target for early neurogenic events promoted by NO in neural stem cells (NSCs).
We show that NO caused S-nitrosylation (SNO) of p21Ras in Cys118, which triggered downstream activation of the ERK/MAPK pathway and proliferation of NSC. Moreover, in cells overexpressing a mutant Ras in which Cys118 was replaced by a serine-C118S-, cells were insensitive to NO, and no increase in SNO, in ERK phosphorylation, or in cell proliferation was observed. We also show that, after seizures, in the presence of NO derived from inducible nitric oxide synthase, there was an increase in p21Ras cysteine modification that was concomitant with the previously described stimulation of proliferation in the dentate gyrus.
Our work identifies p21Ras and its SNO as an early target of NO during signaling events that lead to NSC proliferation and neurogenesis.
Our data highlight Ras SNO as an early event leading to NSC proliferation, and they may provide a target for NO-induced stimulation of neurogenesis with implications for brain repair. Antioxid. Redox Signal. 28, 15-30.
一氧化氮（NO）参与损伤后室下区和海马中海马神经发生的内源性上调。NO 激活的主要神经发生途径之一是细胞外信号调节激酶（ERK）/丝裂原激活蛋白激酶（MAPK）途径，该途径位于表皮生长因子受体下游。然而，NO 通过激活 ERK/MAPK 途径刺激细胞增殖的机制尚不清楚，尽管 p21Ras 似乎是 NO 的最早靶点之一。在这里，我们旨在通过 p21Ras 的翻译后修饰研究 NO 的可能神经发生作用，因为 p21Ras 是 NO 在神经干细胞（NSC）中促进早期神经发生事件的相关靶标。
我们表明，NO 导致 p21Ras 的半胱氨酸 118 发生 S-亚硝基化（SNO），从而触发 ERK/MAPK 途径的下游激活和 NSC 的增殖。此外，在过表达 Cys118 被丝氨酸取代的突变 Ras 的细胞中-C118S-，细胞对 NO 不敏感，并且观察到 SNO、ERK 磷酸化或细胞增殖没有增加。我们还表明，在诱导型一氧化氮合酶存在下，癫痫发作后，p21Ras 半胱氨酸修饰增加，这与先前描述的齿状回增殖刺激同时发生。
我们的工作确定 p21Ras 及其 SNO 是导致 NSC 增殖和神经发生的信号事件中 NO 的早期靶标。
我们的数据强调了 Ras SNO 作为导致 NSC 增殖的早期事件，并可能为 NO 诱导的神经发生刺激提供靶点，这对大脑修复具有重要意义。抗氧化剂。氧化还原信号。28，15-30。
