Endothelial Transcriptome Remodeling in a Mouse Model of Chronic Hypertension

Aims: Hypertension poses a significant challenge to vasculature homeostasis and stands as the most common cardiovascular disease in the world. Its effects are especially profound on vasculature-lining endothelial cells that are directly exposed to the effects of excess pressure. Here, we characterize the in vivo transcriptomic response of cardiac endothelial cells to hypertension using the spontaneous hypertension mouse model BPH/2J. Methods and results: Verification of defective endothelial function in the BPH/2J hypertensive mouse strain was followed by acute isolation of cardiac endothelial cells and transcriptional profiling using RNA sequencing. Gene profiles from normotensive BPN/3J mice were compared to hypertensive animals. We observed over 3000 transcriptional differences between groups including pathways consistent with the cardiac fibrosis found in hypertensive animals. Importantly, many of the fibrosis-linked genes also differ between juvenile pre-hypertensive and adult hypertensive BPH/2J mice, suggesting that these transcriptional differences are hypertension-related. We also show that blood pressure normalization with amlodipine resulted in a subset of genes reversing their expression pattern, supporting the hypertension-dependency of altered gene expression. Yet, other transcripts were recalcitrant to therapeutic intervention illuminating the possibility that hypertension may irreversibly alter some endothelial transcriptional patterns. Conclusions: Hypertension has a profound effect on both function and transcription of endothelial cells, the latter of which was only partially restored with normalization of blood pressure. This study represents one of the first to quantify how endothelial cells are reprogrammed at the molecular level in cardiovascular pathology and advances our understanding of the transcriptional events associated with endothelial dysfunction. Endothelium from hypertensive mice were acutely extracted at two different ages (4 weeks and 22 weeks) and compared to endothelium from 22 week old normotensive mice.研究目的：高血压对血管稳态构成严重威胁，是全球范围内最常见的心血管疾病。其对直接暴露于高压环境的血管内衬内皮细胞的影响尤为显著。本研究采用自发性高血压小鼠模型BPH/2J，解析心脏内皮细胞在高血压刺激下的体内转录组应答特征。 方法与结果：首先验证了BPH/2J高血压小鼠品系存在内皮功能缺陷，随后通过急性分离获取心脏内皮细胞，并利用RNA测序开展转录组分析。将血压正常的BPN/3J小鼠的基因表达谱与高血压小鼠进行对比。两组间共鉴定出超过3000个转录水平差异基因，其中涵盖了与高血压小鼠心脏纤维化相一致的信号通路。值得关注的是，大量与纤维化相关的基因在幼年高血压前期与成年高血压BPH/2J小鼠中同样存在表达差异，提示此类转录差异与高血压的发生发展密切相关。此外，本研究证实，使用氨氯地平使血压恢复正常后，部分基因的表达模式发生逆转，进一步证明了基因表达改变的高血压依赖性。然而，另有一部分转录本无法通过治疗干预得到改善，这表明高血压可能会不可逆地改变部分内皮细胞的转录模式。 结论：高血压对内皮细胞的功能与转录均具有显著影响，其中转录层面的改变仅能通过血压恢复得到部分逆转。本研究是首批在心血管病理条件下量化内皮细胞分子重编程过程的研究之一，加深了我们对内皮功能障碍相关转录事件的理解。本研究从两个不同年龄段（4周龄与22周龄）的高血压小鼠中急性提取内皮细胞，并与22周龄血压正常小鼠的内皮细胞进行对比分析。