Expression of E-FABP in PC12 cells increases neurite extension during differentiation: involvement of n-3 and n-6 fatty acids
Expression of E-FABP in PC12 cells increases neurite extension during differentiation: involvement of n-3 and n-6 fatty acids
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DOI：
10.1111/j.1471-4159.2008.05507.x
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发表时间：
2008-09-01
影响因子：
4.7
通讯作者：
De Leon, Marino
中科院分区：
文献类型：
--
作者：
Liu, Jo-Wen;Almaguel, Frankis G.;De Leon, Marino
表皮脂肪酸结合蛋白（E-FABP）是FABP家族的一员，在发育中的轴突生长和神经损伤后的神经再生过程中在神经元中表现出强烈的表达。本研究探讨了E-FABP表达的影响，在正常的神经突起延伸分化嗜铬细胞瘤细胞（PC 12）的文化补充选定的长链游离脂肪酸（LCFFA）。我们发现E-FABP结合广泛的饱和和不饱和LCFFA，包括那些对神经元分化和轴突生长具有潜在意义的LCFFA，如C22：6 n-3二十二碳六烯酸（DHA）、C20：5 n-3二十碳五烯酸（EPA）和C20：4 n-6花生四烯酸（ARA）。暴露于神经生长因子（NGFDPC 12）的PC 12细胞表现出高E-FABP表达，其被丝裂原活化蛋白激酶激酶（MEK）抑制剂U 0126阻断。显示低E-FABP表达的神经生长因子分化的嗜铬细胞瘤细胞（NGFDPC 12）反义克隆（NGFDPC 12-AS）比仅用载体转染的细胞或NGFDPC 12正义细胞（NGFDPC 12-S）具有更少/更短的神经突。用生物素化的重组E-FABP（生物素-E-FABP）蛋白补充NGFDPC 12-AS细胞恢复正常的神经突生长。NGFDPC 12中生物素-E-FABP的细胞定位主要在细胞质和细胞核区域中检测到。用DHA、EPA或ARA处理NGFDPC 12进一步增强了神经突长度，但它不触发在没有LCFFA补充的分化PC 12细胞中观察到的TrkA或MEK磷酸化或E-FABP mRNA的进一步诱导。值得注意的是，DHA和EPA神经突刺激作用在NGFDPC 12-S中比在NGFDPC 12-AS细胞中更高。这些发现与分化中的PC 12细胞的神经突延伸（包括DHA和EPA的进一步刺激）需要足够的细胞水平的E-FABP的情况一致。
Epidermal fatty acid-binding protein (E-FABP), a member of the family of FABPs, exhibits a robust expression in neurons during axonal growth in development and in nerve regeneration following nerve injury. This study examines the impact of E-FABP expression in normal neurite extension in differentiating pheochromocytoma cell (PC12) cultures supplemented with selected long chain free fatty acids (LCFFA). We found that E-FABP binds to a broad range of saturated and unsaturated LCFFAs, including those with potential interest for neuronal differentiation and axonal growth such as C22:6n-3 docosahexaenoic acid (DHA), C20:5n-3 eicosapentaenoic acid (EPA), and C20:4n-6 arachidonic acid (ARA). PC12 cells exposed to nerve growth factor (NGFDPC12) exhibit high E-FABP expression that is blocked by mitogen-activated protein kinase kinase (MEK) inhibitor U0126. Nerve growth factor-differentiated pheochromocytoma cells (NGFDPC12) antisense clones (NGFDPC12-AS) which exhibit low E-FABP expression have fewer/shorter neurites than cells transfected with vector only or NGFDPC12 sense cells (NGFDPC12-S). Replenishing NGFDPC12-AS cells with biotinylated recombinant E-FABP (biotin-E-FABP) protein restores normal neurite outgrowth. Cellular localization of biotin-E-FABP in NGFDPC12 was detected mostly in the cytoplasm and in the nuclear region. Treatment of NGFDPC12 with DHA, EPA, or ARA further enhances neurite length but it does not trigger further induction of TrkA or MEK phosphorylation or E-FABP mRNA observed in differentiating PC12 cells without LCFFA supplementation. Significantly, DHA and EPA neurite stimulating effects are higher in NGFDPC12-S than in NGFDPC12-AS cells. These findings are consistent with the scenario that neurite extension of differentiating PC12 cells, including further stimulation by DHA and EPA, requires sufficient cellular levels of E-FABP.