Huang Xianxi, Shen Wenjun, Veizades Stefan, Liang Grace, Sayed Nazish, Nguyen Patricia K
Department of Critical Care Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, China.
Division of Cardiovascular Medicine, Stanford University, Stanford, CA, United States.
Front Genet. 2021 Feb 17;12:590377. doi: 10.3389/fgene.2021.590377. eCollection 2021.
Although it is well-known that sex and age are important factors regulating endothelial cell (EC) function, the impact of sex and age on the gene expression of ECs has not been systematically analyzed at the single cell level. In this study, we performed an integrated characterization of the EC transcriptome of five major organs (e.g., fat, heart-aorta, lung, limb muscle, and kidney) isolated from male and female C57BL/6 mice at 3 and 18 months of age. A total of 590 and 252 differentially expressed genes (DEGS) were identified between females and males in the 3- and 18-month subgroups, respectively. Within the younger and older group, there were 177 vs. 178 DEGS in fat, 305 vs. 469 DEGS in heart/aorta, 22 vs. 37 DEGS in kidney, 26 vs. 439 DEGS in limb muscle, and 880 vs. 274 DEGS in lung. Interestingly, LARS2, a mitochondrial leucyl tRNA synthase, involved in the translation of mitochondrially encoded genes was differentially expressed in all organs in males compared to females in the 3-month group while S100a8 and S100a9, which are calcium binding proteins that are increased in inflammatory and autoimmune states, were upregulated in all organs in males at 18 months. Importantly, findings from RNAseq were confirmed by qPCR and Western blot. Gene enrichment analysis found genes enriched in protein targeting, catabolism, mitochondrial electron transport, IL 1- and IL 2- signaling, and Wnt signaling in males vs. angiogenesis and chemotaxis in females at 3 months. In contrast, ECs from males and females at 18-months had up-regulation in similar pathways involved in inflammation and apoptosis. Taken together, our findings suggest that gene expression is largely similar between males and females in both age groups. Compared to younger mice, however, older mice have increased expression of genes involved in inflammation in endothelial cells, which may contribute to the development of chronic, non-communicable diseases like atherosclerosis, hypertension, and Alzheimer's disease with age.
虽然众所周知性别和年龄是调节内皮细胞（EC）功能的重要因素，但性别和年龄对内皮细胞基因表达的影响尚未在单细胞水平上进行系统分析。在本研究中，我们对从3月龄和18月龄的雄性和雌性C57BL/6小鼠分离出的五个主要器官（如脂肪、心脏-主动脉、肺、肢体肌肉和肾脏）的内皮细胞转录组进行了综合表征。在3月龄和18月龄亚组中，分别在雌性和雄性之间鉴定出590个和252个差异表达基因（DEG）。在较年轻和较年长组中，脂肪中有177个对178个DEG，心脏/主动脉中有305个对469个DEG，肾脏中有22个对37个DEG，肢体肌肉中有26个对439个DEG，肺中有880个对274个DEG。有趣的是，参与线粒体编码基因翻译的线粒体亮氨酰tRNA合成酶LARS2在3月龄组中，雄性所有器官中的表达与雌性相比存在差异，而在炎症和自身免疫状态下增加的钙结合蛋白S100a8和S100a9在18月龄时在雄性所有器官中上调。重要的是，RNAseq的结果通过qPCR和蛋白质印迹得到了证实。基因富集分析发现，在3月龄时，雄性中富集于蛋白质靶向、分解代谢、线粒体电子传递、IL-1和IL-2信号传导以及Wnt信号传导的基因，而雌性中富集于血管生成和趋化性的基因。相比之下，18月龄的雄性和雌性内皮细胞在参与炎症和凋亡的相似途径中上调。综上所述，我们的研究结果表明，两个年龄组中雄性和雌性之间的基因表达在很大程度上相似。然而，与年轻小鼠相比，老年小鼠内皮细胞中参与炎症的基因表达增加，这可能随着年龄的增长导致慢性非传染性疾病如动脉粥样硬化、高血压和阿尔茨海默病的发生。
