Signaling pathways in skeletal muscle of Amyotrophic Lateral Sclerosis mouse model

Gene expression analyses through cDNA microarray of fifteen gastrocnemius muscles from transgenic and wild-type SOD1G93A mouse model by the ages of 40 and 80 days old were performed. We used a customized cDNA array containing the cDNA platform comprised of 2352 spots, 326 of them orthologous to mouse, 1384 additional human cDNA sequences, 496 negative controls (DMSO) and 48 positive controls (the Q gene from λ-phage). Gene expression results for SOD1G93A and WT age matched mice pointed to eight up- (LOXL2, PIK4CA, FZD9, CUL1, CTNND1, SNF1LK, PRKX, DNER) and nine down-regulated genes (PIK3C2A, RIPK4, ID2, C1QDC1, EIF2AK2, RAC3, CDS1, INPPL1, TBL1X) at 40 days and also to one up- (PIK3CA) and five down-regulated genes (CD44, EEF2K, FZD2, CREBBP, PIKI3R1) at 80 days. Based on differentially expressed genes, analyses for gene priorization were performed and used to construct a network of protein-protein interaction. The network based on the genes of 40 and 80 days old mice was composed by 251 and 531 genes, respectively. GRB2 and SRC were identified as central genes of both networks. In conclusion, changes in gene expression of skeletal muscle from transgenic ALS mice in pre-symptomatic periods give further evidence of early neuromuscular abnormalities that precede motor neuron death. We performed gene expression analyses by customized cDNA array, using reference design, of fifteen gastrocnemius muscles from transgenic and wild-type SOD1G93A mouse model by the ages of 40 and 80 days old. These differentially expressed lists were submitted to analyses for gene priorization and used to construct a network of protein-protein interaction.

本研究针对40日龄与80日龄的转基因与野生型SOD1G93A小鼠模型的15份腓肠肌（gastrocnemius muscles）样本，开展了cDNA微阵列（cDNA microarray）基因表达分析。本研究使用定制化cDNA芯片，其平台包含2352个点样：其中326个为小鼠同源序列、1384个为额外的人类cDNA序列、496个为阴性对照（二甲基亚砜，DMSO），另有48个阳性对照（λ噬菌体的Q基因）。针对年龄匹配的SOD1G93A转基因小鼠与野生型（WT，Wild Type）小鼠的基因表达结果显示，40日龄时存在8个上调基因（LOXL2、PIK4CA、FZD9、CUL1、CTNND1、SNF1LK、PRKX、DNER）与9个下调基因（PIK3C2A、RIPK4、ID2、C1QDC1、EIF2AK2、RAC3、CDS1、INPPL1、TBL1X）；80日龄时则存在1个上调基因（PIK3CA）与5个下调基因（CD44、EEF2K、FZD2、CREBBP、PIKI3R1）。基于差异表达基因开展基因优先级分析，并用于构建蛋白质-蛋白质相互作用网络：针对40日龄与80日龄小鼠样本构建的网络分别包含251个与531个基因，GRB2与SRC被鉴定为两个网络的核心基因。综上，症状前期的转基因肌萎缩侧索硬化（ALS，Amyotrophic Lateral Sclerosis）小鼠骨骼肌的基因表达变化，为运动神经元死亡前即已存在的早期神经肌肉异常提供了进一步证据。本研究同样采用参考设计方案，通过定制化cDNA芯片对15份40日龄与80日龄的SOD1G93A转基因与野生型小鼠腓肠肌样本开展基因表达分析，上述差异表达基因列表被用于基因优先级分析，并构建蛋白质-蛋白质相互作用网络。