Sensory ataxia and cardiac hypertrophy caused by neurovascular oxidative stress. Sensory ataxia and cardiac hypertrophy caused by neurovascular oxidative stress

In our chemogenetic neurovacular mouse model, DRGs transcriptomic analysis was performed by RNA-seq; Oxidative stress is associated with cardiovascular and neurodegenerative disease. We created transgenic chemogenetic mouse lines expressing yeast D-amino oxidase (DAAO) in endothelial cells and neurons. DAAO generates hydrogen peroxide (H2O2) in target tissues when mice are provided with D-amino acids, causing oxidative stress. DAAO-TGCdh5 transgenic mice express DAAO under control of the putatively endothelial-specific Cdh5 promoter. We provided these mice with D-alanine¬– expecting a vascular phenotype– but found that the mice develop sensory ataxia and neurodegeneration in dorsal root ganglia (DRG), associated with transgene expression within DRG neurons; electron microscopy revealed distorted mitochondria. DAAO-TGCdh5 mice also develop cardiac hypertrophy in response to chemogenetic oxidative stress, and we discovered transgene expression in parasympathetic nodose ganglia innervating the heart. We developed and characterized another transgenic line expressing DAAO under control of a different endothelial cell-specific Tie2 promoter. DAAO-TGTie2 mice express the transgene in endothelium but not neurons, and develop neither ataxia nor cardiac hypertrophy. The combination of ataxia, mitochondrial dysfunction, and cardiac hypertrophy is similar to findings in patients with Friedreich's Ataxia. Our observations confirm that neurovascular oxidative stress is sufficient to cause sensory ataxia and cardiac hypertrophy, and identify the DAAO-TGCdh5 mouse as a potentially informative animal model for Friedreich’s Ataxia. Overall design: RNA-seq of mouse DRGs neuronal tissue. The DRGs neuronal tissue samples were studied and have a set of raw data files, analysis and expression matrix. The total samples were 12 (6 control and 6 treatment). There were 6 replicates for control and 6 for treatment.

在本研究构建的化学遗传学神经血管小鼠模型中，我们通过RNA测序（RNA-seq）对背根神经节（DRGs）开展了转录组分析。氧化应激与心血管疾病及神经退行性疾病密切相关。我们构建了在内皮细胞与神经元中表达酵母D-氨基酸氧化酶（D-amino acid oxidase, DAAO）的转基因化学遗传学小鼠品系。当小鼠摄入D-氨基酸时，DAAO可在靶组织中生成过氧化氢（H₂O₂），进而诱发氧化应激。DAAO-TGCdh5转基因小鼠在被认为具有内皮特异性的Cdh5启动子调控下表达DAAO。我们给这些小鼠饲喂D-丙氨酸，预期可观察到血管表型，却意外发现小鼠出现了感觉性共济失调以及背根神经节（DRG）的神经退行性变，该表型与转基因在DRG神经元中的表达密切相关；电子显微镜检查可见线粒体形态畸变。DAAO-TGCdh5小鼠在化学遗传学诱导的氧化应激下还会出现心肌肥大，我们同时发现该转基因在支配心脏的副交感神经结状神经节中存在表达。我们还构建并表征了另一种在不同的内皮细胞特异性Tie2启动子调控下表达DAAO的转基因小鼠品系。DAAO-TGTie2小鼠仅在内皮细胞中表达该转基因，而不在神经元中表达，既未出现共济失调，也未发生心肌肥大。共济失调、线粒体功能障碍与心肌肥大的联合表型，与弗里德赖希共济失调（Friedreich's Ataxia）患者的临床特征高度相似。本研究结果证实，神经血管源性氧化应激足以诱发感觉性共济失调与心肌肥大，并确认DAAO-TGCdh5小鼠可作为研究弗里德赖希共济失调的潜在理想动物模型。整体实验设计：对小鼠DRG神经元组织进行RNA测序。本研究对DRG神经元组织样本进行了系统分析，配套包含原始数据文件、分析结果及表达矩阵。总样本量为12例，其中对照组与处理组各6例，每组均设6个生物学重复。