Department of Pharmacology, DNA Repair Center, Chosun University School of Medicine, Gwangju 501-759, Korea.
Korean J Physiol Pharmacol. 2009 Oct;13(5):349-56. doi: 10.4196/kjpp.2009.13.5.349. Epub 2009 Oct 31.
We previously reported that glial cell line-derived neurotropic factor (GDNF) receptor alpha1 (GFRalpha1) is a direct target of apurinic/apyrimidinic endonuclease 1 (Ape1/Ref-1). In the present study, we further analyzed the physiological roles of Ape1/Ref-1-induced GFRalpha1 expression in Neuro2a mouse neuroblastoma cells. Ape1/Ref-1 expression caused the clustering of GFRalpha1 immunoreactivity in lipid rafts in response to GDNF. We also found that Ret, a downstream target of GFRalpha1, was functionally activated by GDNF in Ape1/Ref-1-expressing cells. Moreover, GDNF promoted the proliferation of Ape1/Ref-1-expressing Neuro2a cells. Furthermore, GFRalpha1-specific RNA experiments demonstrated that the downregulation of GFRalpha1 by siRNA in Ape1/Ref-1-expressing cells impaired the ability of GDNF to phosphorylate Akt and PLCgamma-1 and to stimulate cellular proliferation. These results show an association between Ape1/Ref-1 and GDNF/GFRalpha signaling, and suggest a potential molecular mechanism for the involvement of Ape1/Ref-1 in neuronal proliferation.
我们之前曾报道过，神经胶质细胞源性神经营养因子（GDNF）受体 alpha1（GFRalpha1）是脱嘌呤/脱嘧啶内切酶 1（Ape1/Ref-1）的直接靶标。在本研究中，我们进一步分析了 Ape1/Ref-1 诱导的 GFRalpha1 在 Neuro2a 小鼠神经母细胞瘤细胞中表达的生理作用。Ape1/Ref-1 的表达导致 GFRalpha1 免疫反应在神经胶质细胞源性神经营养因子（GDNF）刺激下在脂筏中聚集。我们还发现，GFRalpha1 的下游靶点 Ret 在 Ape1/Ref-1 表达细胞中被 GDNF 功能性激活。此外，GDNF 促进 Ape1/Ref-1 表达的 Neuro2a 细胞的增殖。此外，GFRalpha1 特异性 RNA 实验表明，Ape1/Ref-1 表达细胞中的 GFRalpha1 下调 siRNA 削弱了 GDNF 磷酸化 Akt 和 PLCgamma-1 并刺激细胞增殖的能力。这些结果表明 Ape1/Ref-1 与 GDNF/GFRalpha 信号之间存在关联，并提示 Ape1/Ref-1 参与神经元增殖的潜在分子机制。
