The hypoxia induced changes in miRNA in RNA-induced silencing complexes and HIFs induced miRNAs in human endothelial cells. The hypoxia induced changes in miRNA in RNA-induced silencing complexes and HIFs induced miRNAs in human endothelial cells

What governs the transition between the two HIFs (the HIF switch) and the role of miRNAs in this regulation is not completely clear. Using genome-wide expression studies on the miRNA content of RNA-induced silencing complex (RISC) in HUVECs exposed to hypoxia compared to the global miRNA-Seq analysis revealed dramatic differences between the two. In our analyses, compared the miRNA and mRNA levels in RISC at 2 hours (mainly HIF-1 driven), 8 hours (HIF-1 and HIF-2 elevated), and 16 hours (mainly HIF-2 driven) in a gene ontology context. This allowed for determining the direct impact of the miRNAs in modulating the cellular signaling pathways involved in the adaptive response. Furthermore, we demonstrate that the hypoxic levels of the vast majority of HIF-1-dependent miRNAs (including miR-210-3p) are also HIF-2 dependent, and that HIF-2 specifically governs the expression of 11 specific miRNAs Overall design: Examination of miRNA profiles in HUVECs exposed to hypoxia, hypoxia mimetics, with and without HIF1A and EPAS1 silencing

目前尚不完全明确调控两种缺氧诱导因子（HIF, Hypoxia-Inducible Factor）之间转换（即HIF开关）的机制，以及微小RNA（miRNA）在该调控过程中发挥的作用。本研究通过对缺氧处理的人脐静脉内皮细胞（HUVECs）内RNA诱导沉默复合体（RISC, RNA-induced silencing complex）中的微小RNA组分开展全基因组表达分析，并与全局微小RNA测序（miRNA-Seq）结果对比，发现两组样本间存在显著差异。在本研究的分析中，我们基于基因本体论（Gene Ontology, GO）注释背景，对比了缺氧处理2小时（主要由HIF-1驱动）、8小时（HIF-1与HIF-2均上调）及16小时（主要由HIF-2驱动）下，RISC内的微小RNA与信使RNA（mRNA）水平。这一分析策略得以明确微小RNA在调控细胞适应性应答相关信号通路中的直接作用。此外，本研究证实，绝大多数依赖于HIF-1的微小RNA（包括miR-210-3p），其缺氧诱导的表达水平同时也受HIF-2调控；且HIF-2可特异性调控11种特定微小RNA的表达。本研究整体实验设计：对经缺氧处理、缺氧模拟物处理，且分别或同时敲低HIF1A与EPAS1，或未进行基因沉默的人脐静脉内皮细胞中的微小RNA表达谱进行检测。