Department of Physiology, Emory University School of Medicine, Atlanta, Georgia, USA.
J Neurochem. 2012 Jul;122(2):333-43. doi: 10.1111/j.1471-4159.2012.07780.x. Epub 2012 May 30.
Regulator of G-protein signaling-10 (RGS10) is a GTPase activating protein for Gαi/q/z subunits that is highly expressed in the immune system and in a broad range of brain regions including the hippocampus, striatum, dorsal raphe, and ventral midbrain. Previously, we reported that RGS10-null mice display increased vulnerability to chronic systemic inflammation-induced degeneration of nigral dopaminergic (DA) neurons. Given that RGS10 is expressed in DA neurons, we investigated the extent to which RGS10 regulates cell survival under conditions of inflammatory stress. Because of the inherent limitations associated with use of primary DA neurons for biochemical analyses, we employed a well-characterized ventral mesencephalon DA neuroblastoma cell line (MN9D) for our studies. We found that stable over-expression of RGS10 rendered them resistant to TNF-induced cytotoxicity; whereas MN9D cells expressing mutant RGS10-S168A (which is resistant to phosphorylation by protein kinase A at a serine residue that promotes its nuclear translocation) showed similar sensitivity to TNF as the parental MN9D cells. Using biochemical and pharmacologic approaches, we identified protein kinase A and the downstream phospho-cAMP response element-binding signaling pathway (and ruled out ERK 1/2, JNK, and NFkB) as key mediators of the neuroprotective effect of RGS10 against inflammatory stress.
G 蛋白信号调节因子 10（RGS10）是一种 Gαi/q/z 亚基的 GTP 酶激活蛋白，在免疫系统和广泛的脑区中高度表达，包括海马体、纹状体、背侧中缝核和腹侧中脑。以前，我们报道过 RGS10 敲除小鼠对慢性全身炎症诱导的黑质多巴胺能（DA）神经元变性表现出更高的易感性。鉴于 RGS10 在 DA 神经元中表达，我们研究了在炎症应激条件下 RGS10 调节细胞存活的程度。由于使用原代 DA 神经元进行生化分析存在固有限制，我们采用了一种经过充分表征的腹侧中脑 DA 神经母细胞瘤细胞系（MN9D）进行研究。我们发现，稳定过表达 RGS10 可使它们对 TNF 诱导的细胞毒性具有抗性；而表达突变型 RGS10-S168A（对蛋白激酶 A 在促进其核易位的丝氨酸残基上的磷酸化具有抗性）的 MN9D 细胞对 TNF 的敏感性与亲本 MN9D 细胞相似。通过生化和药理学方法，我们确定蛋白激酶 A 和下游磷酸-cAMP 反应元件结合信号通路（并排除了 ERK 1/2、JNK 和 NFkB）是 RGS10 对抗炎症应激的神经保护作用的关键介质。
