Association of NOTCH3 with Elastic Fiber Dispersion in the Infrarenal Abdominal Aorta of Cynomolgus Monkeys. Association of NOTCH3 with Elastic Fiber Dispersion in the Infrarenal Abdominal Aorta of Cynomolgus Monkeys

OBJECTIVE: The regional heterogeneity of vascular components and transcriptomes is an important determinant of aortic biology. This notion has been explored in multiple mouse studies. In the present study, we examined the regional heterogeneity of aortas in non-human primates. APPROACH AND RESULTS: Aortic samples were harvested from the ascending, descending, suprarenal, and infrarenal regions of young control monkeys and adult monkeys provided with high fructose for 3 years. The regional heterogeneity of aortic structure and transcriptomes was examined by histological and bulk RNA sequencing analyses. Immunostaining of CD31 and αSMA revealed that endothelial and smooth muscle cells were distributed homogeneously across the aortic regions. In contrast, elastic fibers were less abundant and dispersed in the infrarenal aorta compared to other regions and associated with collagen deposition. Bulk RNA sequencing identified a distinct transcriptome related to the Notch signaling pathway in the infrarenal aorta with significantly increased NOTCH3 mRNA compared to other regions. Immunostaining revealed that NOTCH3 protein was increased in the media of the infrarenal aorta. The abundance of medial NOTCH3 was positively correlated with the dispersion of elastic fibers. Adult cynomolgus monkeys provided with high fructose displayed vascular wall remodeling, such as smooth muscle cell loss and elastic fiber disruption, predominantly in the infrarenal region. The correlation between NOTCH3 and elastic fiber dispersion was enhanced in these monkeys. CONCLUSION: Aortas of young cynomolgus monkeys display regional heterogeneity of their transcriptome and the structure of elastin and collagens. Elastic fibers in the infrarenal aorta are dispersed along with upregulation of medial NOTCH3. Overall design: Comparative gene expression profiling analysis of RNA-seq data for ascending, descending, suprarenal, and infrarenal aortas from normal young cynomolgus monkeys.

研究目的：血管组分与转录组的区域异质性是主动脉生物学的重要决定因素。该学术观点已在多项小鼠研究中得到探索。本研究针对非人灵长类动物的主动脉区域异质性展开分析。

方法与结果：本研究采集了年轻对照食蟹猴（cynomolgus monkeys）与经高果糖喂养3年的成年食蟹猴的升主动脉、降主动脉、肾上区主动脉及肾下区主动脉样本。通过组织学检测与批量RNA测序（bulk RNA sequencing）分析，对主动脉结构与转录组的区域异质性进行评估。CD31与αSMA免疫染色结果显示，内皮细胞与平滑肌细胞在各主动脉区域呈均匀分布。与之相反，相较于其他主动脉区域，肾下区主动脉的弹性纤维含量更低且分布散乱，且该现象与胶原沉积密切相关。批量RNA测序鉴定发现，肾下区主动脉存在与Notch信号通路（Notch signaling pathway）相关的独特转录组特征，其NOTCH3 mRNA表达水平较其他区域显著升高。免疫染色结果显示，肾下区主动脉中膜的NOTCH3蛋白表达水平上调。中膜NOTCH3的丰度与弹性纤维的散乱程度呈显著正相关。经高果糖喂养3年的成年食蟹猴出现血管壁重构现象，表现为平滑肌细胞丢失与弹性纤维破坏，且该病理改变主要集中于肾下区主动脉。在该组食蟹猴中，NOTCH3表达水平与弹性纤维散乱程度之间的相关性进一步增强。

结论：年轻食蟹猴的主动脉存在转录组以及弹性蛋白与胶原结构的区域异质性。肾下区主动脉的弹性纤维分布散乱，同时伴随中膜NOTCH3表达上调。

整体实验设计：对正常年轻食蟹猴升主动脉、降主动脉、肾上区主动脉及肾下区主动脉的RNA-seq数据开展比较基因表达谱分析。