Langmesser Sonja, Cerezo-Guisado Maria I, Lorenzo Maria J, Garcia-Marin Luis J, Bragado Maria J
Departamento de Fisiología, Biología Molecular y Genética, Universidad de Extremadura, Cáceres, Spain.
J Cell Biochem. 2007 Mar 1;100(4):851-64. doi: 10.1002/jcb.21193.
Cholecystokinin (CCK) is one of the most abundant neuropeptides in the central nervous system (CNS) where it promotes important functions by activation of receptors CCK1 and CCK2. Our aim was to investigate CCK receptors expression and their downstream intracellular signaling in immortalized rat brain neuroblasts. Results show that CCK1 and CCK2 receptor mRNAs and CCK2 receptor protein are expressed in neuroblasts. CCK incubation of neuroblasts leads to stimulation in a time-dependent manner of several signaling pathways, such as tyrosine phosphorylation of adaptor proteins paxillin and p130(Cas), phosphorylation of p44/p42 ERKs as well as PKB (Ser473). Moreover, CCK-8 stimulates the DNA-binding activity of the transcription factor AP-1. The CCK2 receptor agonist gastrin stimulates ERK1/2 phosphorylation in a comparable degree as CCK does. ERK1/2 phosphorylation activated by CCK-8 was markedly inhibited by the CCK2 receptor antagonist CR2945. Incubation for 48 h with CCK-8 increases neuroblasts viability in a similar degree as EGF. In summary, our data clearly identify CCK1 and CCK2 receptor mRNAs and CCK2 receptor protein in brain neuroblasts and show that incubation with CCK promotes cell proliferation and activates the phosphorylation of survival transduction pathways. Stimulation of ERK1/2 phosphorylation by CCK is mainly mediated by the CCK2 receptor. Moreover, this work might provide a novel model of proliferating neuronal cells to further study the biochemical mechanisms by which the neuropeptide CCK exerts its actions in the CNS.
胆囊收缩素（CCK）是中枢神经系统（CNS）中含量最丰富的神经肽之一，它通过激活CCK1和CCK2受体来促进重要功能。我们的目的是研究永生化大鼠脑成神经细胞中CCK受体的表达及其下游细胞内信号传导。结果显示，成神经细胞中表达CCK1和CCK2受体mRNA以及CCK2受体蛋白。用CCK孵育成神经细胞会以时间依赖性方式刺激多种信号通路，如衔接蛋白桩蛋白和p130（Cas）的酪氨酸磷酸化、p44/p42细胞外信号调节激酶（ERK）以及蛋白激酶B（Ser473）的磷酸化。此外，CCK-8刺激转录因子AP-1的DNA结合活性。CCK2受体激动剂胃泌素刺激ERK1/2磷酸化的程度与CCK相当。CCK-8激活的ERK1/2磷酸化被CCK2受体拮抗剂CR2945显著抑制。用CCK-8孵育48小时可使成神经细胞活力增加，程度与表皮生长因子（EGF）相似。总之，我们的数据清楚地鉴定了脑成神经细胞中的CCK1和CCK2受体mRNA以及CCK2受体蛋白，并表明用CCK孵育可促进细胞增殖并激活存活转导通路的磷酸化。CCK对ERK1/2磷酸化的刺激主要由CCK2受体介导。此外，这项工作可能提供一种增殖神经元细胞的新模型，以进一步研究神经肽CCK在中枢神经系统中发挥作用的生化机制。
