Transcriptome analysis of Largemyd and Dmdmdx/Largemyd muscles in comparison to Dmdmdx: what make them different?. Mus musculus

Transcriptome analysis of hindlimb muscles from dystrophic mice Muscular dystrophies (MD) are a clinically and genetically heterogeneous group of mendelian diseases. The underlying pathophysiology and phenotypic variability in each form are much more complex, suggesting the involvement of many other genes. Thus, here we studied the whole genome expression profile in muscles from three mice models for MD, at different time points: Dmdmdx, carrying a mutation in dystrophin gene, Largemyd-/- with mutation in Large and Dmdmdx/Largemyd-/- bearing both mutations. The main objective was to identify altered biological functions, contributing to the understanding of disease and to the identification of prognostic biomarkers and points for therapeutic intervention. We identified a substantial number of differentially expressed genes (DEGs) in each model, reflecting diseases' complexity. The main biological process affected in the three strains was immune system, accounting for the majority of enriched functional categories, followed by degeneration/regeneration and extracellular matrix remodeling processes.The most notable differences were in 21-day-old Dmdmdx, with a high proportion of DEGs related to regenerative capacity observed in this mouse. The new Dmdmdx/Largemyd-/- model did not show a highly different transcriptome from the parental lineages, with a profile closer to Largemyd-/-, but not bearing the same regenerative potential as Dmdmdx. This is the first report about transcriptome profile of a mouse model for congenital MD and Dmdmdx/Largemyd. By comparing the profiles studied, we conclude that alterations in biological functions due to the dystrophic process are very similar, and that the intense regeneration in Dmdmdx involves a large number of activated genes, not differentially expressed in the other two strains. Overall design: We analyzed calf muscles from 5 animals of each lineage (Dmdmdx, Largemyd, Dmdmdx/Largemyd and C57Bl/6 as normal control), at three ages (21 days, 3 months and 6 months) using the Affymetrix Mouse Gene 1.0 ST platform. Array data was processed by Expression Console. No technical replicates were performed.

肌营养不良症（Muscular dystrophies, MD）小鼠后肢肌肉的转录组分析。肌营养不良症是一类临床与遗传异质性极强的孟德尔遗传病。其各亚型的潜在病理生理学机制与表型异质性更为复杂，提示尚有诸多其他基因参与其中。为此，本研究针对三种肌营养不良症小鼠模型的肌肉组织全基因组表达谱展开分析，涵盖多个时间节点：分别为携带肌营养不良蛋白（dystrophin）基因突变的Dmdmdx模型、携带有Large基因突变的Largemyd-/-模型，以及同时携带两种突变的Dmdmdx/Largemyd-/-模型。本研究的核心目标为鉴定异常调控的生物学功能，以期加深对疾病的理解，并筛选预后生物标志物与治疗干预靶点。我们在每个模型中均鉴定出大量差异表达基因（differentially expressed genes, DEGs），反映了该类疾病的复杂性。三种模型共同受影响的主要生物学过程为免疫系统相关通路，其富集的功能类别占比最高，其次为变性/再生与细胞外基质重塑过程。最显著的差异见于21日龄的Dmdmdx模型，该模型中与再生能力相关的差异表达基因占比极高。新型双突变模型Dmdmdx/Largemyd-/-的转录组与亲本品系并未出现显著差异，其表达谱更接近Largemyd-/-模型，但未具备Dmdmdx模型的强再生能力。本研究首次报道了先天性肌营养不良症小鼠模型与Dmdmdx/Largemyd双突变模型的转录组特征。通过对比各研究组的表达谱，我们得出结论：肌营养不良病理过程引发的生物学功能改变具有高度相似性；而Dmdmdx模型中的强再生过程涉及大量激活的基因，这类基因在另外两个模型中并未呈现差异表达。实验设计概述：我们使用Affymetrix Mouse Gene 1.0 ST芯片平台，对每个品系（Dmdmdx、Largemyd、Dmdmdx/Largemyd以及正常对照C57Bl/6）各5只动物的小腿肌肉组织，在三个年龄阶段（21日龄、3月龄、6月龄）进行了转录组分析。芯片数据通过Expression Console软件进行处理，未设置技术重复。