The Role of MKPs in Oxidative Neuronal Cell Death

缺血引起的大部分神经元损伤不是即时的，而是延迟的，被认为是由于兴奋毒性细胞死亡之外，压倒性的氧化应激和随后的细胞凋亡。同样，其他衰弱的疾病，如帕金森氏病和阿尔茨海默病，也与慢性氧化应激和神经退化有关。这项建议的目的是研究在神经元氧化应激过程中发生的信号事件，并设想在这种情况下可以防止神经元死亡的方法。谷氨酸诱导的氧化毒性，无论是在小鼠海马细胞系HT22中，还是在原代未成熟神经元皮质神经元中，都是一个被广泛研究的氧化应激和神经细胞死亡的模型。关于丝裂原活化蛋白激酶(MAPK)磷酸酶(MKPs)在神经元氧化应激中的作用，人们知之甚少。我们计划研究谷氨酸诱导的氧化应激过程中HT22和原代皮质神经元中MKPs表达和活性的变化。此外，MKP3及其催化失活突变体MKP3 C293S将被导入这两个细胞系统，以研究该磷酸酶消除谷氨酸诱导的氧化毒性的能力。进一步的实验包括构建配体诱导的MKP3-雌激素受体配体结合域(MKP3-ER LBD)，这将允许在时间上控制MKP3对他莫昔芬的反应。

Much of the neuronal damage resulting from ischemia is not immediate but delayed and is thought to be due, in addition to excitotoxic cell death, to overwhelming oxidative stress and subsequent apoptosis. Similarly, other debilitating diseases such as Parkinson's Disease and Alzheimer's Disease have been linked with chronic oxidative stress and neurodegeration. It is the purpose of this proposal to investigate the signaling events that occur during oxidative stress in neurons and to conceive of approaches that may prevent neuronal death in this context. Glutamate-induced oxidative toxicity, both in the mouse hippocampal cell line, HT22, and primary immature neuronal cortical neurons, is a well-studied model of oxidative stress and neuronal cell death. Little is known about the role of the mitogen-activated protein kinase (MAPK) phosphatases (MKPs) during oxidative stress in neurons. We plan to investigate changes of expression and activity of MKPs during glutamate-induced oxidative stress in both HT22 and primary cortical neurons. In addition, MKP3 and its catalytically inactive mutant, MKP3 C293S, will be transfected into both cell systems in order to investigate the ability of this phosphatase to abrogate glutamate-induced oxidative toxicity. Further experiments involving the construction of a ligand- inducible MKP3-estrogen receptor ligand-binding domain (MKP3-ER LBD) will allow the temporal control of MKP3 activity in response to tamoxifen.