Weightlessness-induced cardiovascular dysfunction can lead to physiological and pathological consequences. It has been shown that spaceflight or simulated microgravity can alter expression profiles of some microRNAs (miRNAs). Here, we attempt to identify the role of miRNAs in human umbilical vein endothelial cells (HUVECs) apoptosis under simulated microgravity. RNA-sequencing and quantitative real-time PCR (qRT-PCR) assays were used to identify differentially expressed miRNAs in HUVECs under simulated microgravity. Then we obtained the target genes of these miRNAs through target analysis software. Moreover, GO and KEGG enrichment analysis were performed. The effects of these miRNAs on HUVECs apoptosis were evaluated by flow cytometry, Western blot and Hoechst staining. Furthermore, we obtained the target gene of miR-27b-5p by luciferase assay, qRT-PCR and Western blot. Finally, we investigated the relationship between this target gene and miR-27b-5p in HUVECs apoptosis under normal gravity or simulated microgravity. We found 29 differentially expressed miRNAs in HUVECs under simulated microgravity. Of them, the expressions of 3 miRNAs were validated by qRT-PCR. We demonstrated that miR-27b-5p affected HUVECs apoptosis by inhibiting zinc fingers and homeoboxes 1 (ZHX1). Our results reported here demonstrate for the first time that simulated microgravity can alter the expression of some miRNAs in HUVECs and miR-27b-5p may protect HUVECs from apoptosis under simulated microgravity by targeting ZHX1.

中文翻译：

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miR-27b-5p对模拟微重力诱导的人血管内皮细胞凋亡的影响。

失重引起的心血管功能障碍可导致生理和病理后果。已经显示，太空飞行或模拟的微重力可以改变某些微RNA（miRNA）的表达谱。在这里，我们试图确定miRNA在模拟微重力下在人脐静脉内皮细胞（HUVEC）凋亡中的作用。RNA测序和定量实时PCR（qRT-PCR）分析用于鉴定在微重力作用下HUVEC中差异表达的miRNA。然后我们通过靶标分析软件获得了这些miRNA的靶标基因。此外，进行了GO和KEGG富集分析。通过流式细胞术，Western印迹和Hoechst染色评估了这些miRNA对HUVEC凋亡的影响。此外，我们通过萤光素酶测定获得了miR-27b-5p的靶基因，qRT-PCR和蛋白质印迹。最后，我们研究了在正常重力或模拟微重力下，HUVECs凋亡中该靶基因与miR-27b-5p之间的关系。我们在模拟微重力下在HUVEC中发现了29个差异表达的miRNA。其中，通过qRT-PCR验证了3种miRNA的表达。我们证明了miR-27b-5p通过抑制锌指和同源盒1（ZHX1）影响HUVEC的凋亡。我们在这里报道的结果首次证明模拟微重力可以改变HUVEC中某些miRNA的表达，而miR-27b-5p可以通过靶向ZHX1在模拟微重力下保护HUVEC免受凋亡。我们在模拟微重力下在HUVEC中发现了29个差异表达的miRNA。其中，通过qRT-PCR验证了3种miRNA的表达。我们证明了miR-27b-5p通过抑制锌指和同源盒1（ZHX1）影响HUVEC的凋亡。我们在这里报道的结果首次证明模拟微重力可以改变HUVEC中某些miRNA的表达，而miR-27b-5p可以通过靶向ZHX1在模拟微重力下保护HUVEC免受凋亡。我们在模拟微重力下在HUVEC中发现了29个差异表达的miRNA。其中，通过qRT-PCR验证了3种miRNA的表达。我们证明了miR-27b-5p通过抑制锌指和同源盒1（ZHX1）影响HUVEC的凋亡。我们在这里报道的结果首次证明模拟微重力可以改变HUVEC中某些miRNA的表达，而miR-27b-5p可以通过靶向ZHX1在模拟微重力下保护HUVEC免受凋亡。