Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Gdansk, Poland.
Laboratory of Bioinformatics, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland.
FASEB J. 2022 Jul;36(7):e22412. doi: 10.1096/fj.202101987R.
The cellular adaptive response to hypoxia relies on the expression of hypoxia-inducible factors (HIFs), HIF-1 and HIF-2. HIFs regulate global gene expression changes during hypoxia that are necessary for restoring oxygen homeostasis and promoting cell survival. In the early stages of hypoxia, HIF-1 is elevated, whereas at the later stages, HIF-2 becomes the predominant form. What governs the transition between the two HIFs (the HIF switch) and the role of miRNAs in this regulation are not completely clear. Genome-wide expression studies on the miRNA content of RNA-induced silencing complexes (RISC) in HUVECs exposed to hypoxia compared to the global miRNA-Seq analysis revealed very specific differences between these two populations. We analyzed the miRNA and mRNA composition of RISC at 2 h (mainly HIF-1 driven), 8 h (HIF-1 and HIF-2 elevated), and 16 h (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 hypoxic adaptive response. Our results indicate that the miRNA-mRNA RISC components control the adaptive responses, and this does not always rely on the miRNA transcriptional elevations during hypoxia. 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 governs the expression of 11 specific miRNAs. In summary, the switch from HIF-1 to HIF-2 during hypoxia provides an important level of miRNA-driven control in the adaptive pathways in endothelial cells.
细胞对缺氧的适应性反应依赖于缺氧诱导因子 (HIFs) 的表达，即 HIF-1 和 HIF-2。HIFs 在缺氧期间调节全局基因表达变化，这些变化对于恢复氧平衡和促进细胞存活是必要的。在缺氧的早期阶段，HIF-1 升高，而在后期阶段，HIF-2 成为主要形式。是什么控制了两种 HIF 之间的转换（HIF 开关）以及 miRNA 在这种调节中的作用尚不完全清楚。与全球 miRNA-Seq 分析相比，对缺氧暴露的 HUVECs 的 RNA 诱导沉默复合物 (RISC) 的 miRNA 内容进行的全基因组表达研究揭示了这两种群体之间非常特殊的差异。我们在基因本体论背景下分析了 RISC 在 2 h（主要由 HIF-1 驱动）、8 h（HIF-1 和 HIF-2 升高）和 16 h（主要由 HIF-2 驱动）时的 miRNA 和 mRNA 组成。这使得可以确定 miRNA 直接调节参与缺氧适应性反应的细胞信号通路的直接影响。我们的结果表明，miRNA-mRNA RISC 成分控制着适应性反应，而这并不总是依赖于缺氧期间 miRNA 的转录升高。此外，我们证明了绝大多数 HIF-1 依赖性 miRNA（包括 miR-210-3p）的缺氧水平也依赖于 HIF-2，并且 HIF-2 控制着 11 种特定 miRNA 的表达。总之，缺氧期间从 HIF-1 到 HIF-2 的转换为内皮细胞中的适应性途径提供了重要的 miRNA 驱动控制水平。
