Lopez-Coviella Ignacio, Follettie Maximillian T, Mellott Tiffany J, Kovacheva Vesela P, Slack Barbara E, Diesl Veronica, Berse Brygida, Thies R Scott, Blusztajn Jan Krzysztof
Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA 02118, USA.
Proc Natl Acad Sci U S A. 2005 May 10;102(19):6984-9. doi: 10.1073/pnas.0502097102. Epub 2005 May 3.
Basal forebrain cholinergic neurons (BFCN) participate in processes of learning, memory, and attention. Little is known about the genes expressed by BFCN and the extracellular signals that control their expression. Previous studies showed that bone morphogenetic protein (BMP) 9 induces and maintains the cholinergic phenotype of embryonic BFCN. We measured gene expression patterns in septal cultures of embryonic day 14 mice and rats grown in the presence or absence of BMP9 by using species-specific microarrays and validated the RNA expression data of selected genes by immunoblot and immunocytochemistry analysis of their protein products. BMP9 enhanced the expression of multiple genes in a time-dependent and, in most cases, reversible manner. The set of BMP9-responsive genes was concordant between mouse and rat and included genes encoding cell-cycle/growth control proteins, transcription factors, signal transduction molecules, extracellular matrix, and adhesion molecules, enzymes, transporters, and chaperonins. BMP9 induced the p75 neurotrophin receptor (NGFR), a marker of BFCN, and Cntf and Serpinf1, two trophic factors for cholinergic neurons, suggesting that BMP9 creates a trophic environment for BFCN. To determine whether the genes induced by BMP9 in culture were constituents of the BFCN transcriptome, we purified BFCN from embryonic day 18 mouse septum by using fluorescence-activated cell sorting of NGFR(+) cells and profiled mRNA expression of these and NGFR(-) cells. Approximately 30% of genes induced by BMP9 in vitro were overexpressed in purified BFCN, indicating that they belong to the BFCN transcriptome in situ and suggesting that BMP signaling contributes to maturation of BFCN in vivo.
基底前脑胆碱能神经元(BFCN)参与学习、记忆和注意力过程。关于BFCN表达的基因以及控制其表达的细胞外信号,我们所知甚少。先前的研究表明,骨形态发生蛋白(BMP)9诱导并维持胚胎BFCN的胆碱能表型。我们使用物种特异性微阵列测量了在有或没有BMP9的情况下培养的胚胎第14天小鼠和大鼠隔区培养物中的基因表达模式,并通过对其蛋白质产物进行免疫印迹和免疫细胞化学分析来验证所选基因的RNA表达数据。BMP9以时间依赖性方式增强了多个基因的表达,并且在大多数情况下是可逆的。小鼠和大鼠之间对BMP9有反应的基因集是一致的,包括编码细胞周期/生长控制蛋白、转录因子、信号转导分子、细胞外基质和粘附分子、酶、转运蛋白和伴侣蛋白的基因。BMP9诱导了BFCN的标志物p75神经营养因子受体(NGFR)以及胆碱能神经元的两种营养因子Cntf和Serpinf1,这表明BMP9为BFCN创造了一个营养环境。为了确定BMP9在培养物中诱导的基因是否是BFCN转录组的组成部分,我们通过对NGFR(+)细胞进行荧光激活细胞分选,从胚胎第18天小鼠隔区中纯化了BFCN,并分析了这些细胞和NGFR(-)细胞的mRNA表达。在体外由BMP9诱导的基因中,约30%在纯化的BFCN中过度表达,这表明它们属于原位BFCN转录组,并表明BMP信号传导有助于体内BFCN的成熟。