Wibrand Karin, Messaoudi Elhoucine, Håvik Bjarte, Steenslid Vibeke, Løvlie Roger, Steen Vidar M, Bramham Clive R
Department of Biomedicine and Bergen Mental Health Research Center, Section for Physiology, University of Bergen, Jonas Liens vei 91, N-5009 Bergen, Norway.
Eur J Neurosci. 2006 Mar;23(6):1501-11. doi: 10.1111/j.1460-9568.2006.04687.x.
Brain-derived neurotrophic factor (BDNF) is a critical regulator of transcription-dependent adaptive neuronal responses, such as long-term potentiation (LTP). Brief infusion of BDNF into the dentate gyrus of adult anesthetized rats triggers stable LTP at medial perforant path-granule synapses that is transcription-dependent and requires induction of the immediate early gene Arc. Rather than acting alone, Arc is likely to be part of a larger BDNF-induced transcriptional program. Here, we used cDNA microarray expression profiling to search for genes co-upregulated with Arc 3 h after BDNF-LTP induction. Of nine cDNAs encoding for known genes and up-regulated more than four-fold, we selected five genes, Narp, neuritin, ADP-ribosylation factor-like protein-4 (ARL4L), TGF-beta-induced immediate early gene-1 (TIEG1) and CARP, for further validation. Real-time PCR confirmed robust up-regulation of these genes in an independent set of BDNF-LTP experiments, whereas infusion of the control protein cytochrome C had no effect. In situ hybridization histochemistry further revealed up-regulation of all five genes in somata of post-synaptic granule cells following both BDNF-LTP and high-frequency stimulation-induced LTP. While Arc synthesis is critical for local actin polymerization and stable LTP formation, several of the co-upregulated genes have known functions in excitatory synaptogenesis, axon guidance and glutamate receptor clustering. These results provide novel insight into gene expression responses underlying BDNF-induced synaptic consolidation in the adult brain in vivo.
脑源性神经营养因子(BDNF)是转录依赖性适应性神经元反应(如长时程增强,LTP)的关键调节因子。向成年麻醉大鼠的齿状回短暂注入BDNF会在内侧穿通通路-颗粒突触处引发稳定的LTP,该LTP是转录依赖性的,并且需要诱导即刻早期基因Arc。Arc并非单独起作用,它可能是更大的BDNF诱导转录程序的一部分。在这里,我们使用cDNA微阵列表达谱来寻找BDNF-LTP诱导后3小时与Arc共同上调的基因。在九个编码已知基因且上调超过四倍的cDNA中,我们选择了五个基因,即Narp、神经突素、ADP核糖基化因子样蛋白4(ARL4L)、转化生长因子-β诱导即刻早期基因-1(TIEG1)和CARP,进行进一步验证。实时PCR在另一组BDNF-LTP实验中证实了这些基因的强烈上调,而注入对照蛋白细胞色素C则没有效果。原位杂交组织化学进一步显示,在BDNF-LTP和高频刺激诱导的LTP后,突触后颗粒细胞的胞体中所有五个基因均上调。虽然Arc的合成对于局部肌动蛋白聚合和稳定的LTP形成至关重要,但一些共同上调的基因在兴奋性突触形成、轴突导向和谷氨酸受体聚集方面具有已知功能。这些结果为成年大脑中BDNF诱导的突触巩固背后的基因表达反应提供了新的见解。