[Circular RNA expression profiles and circRNA-miRNA-mRNA crosstalk in pre-eclamptic placenta].

Objective: To identify the expression profile of circular RNA (circRNA) in placenta of pre-eclampsia (PE) pregnant women by high-throughput sequencing, and to construct the circRNA-microRNA (miRNA)-messenger RNA (mRNA) interaction network, so as to reveal the related pathways and regulatory mechanisms of PE. Methods: The clinical data and placentas of 42 women with PE (PE group) and 30 normal pregnant women (control group) who delivered in West China Second University Hospital from November 2019 to June 2021 were collected. (1) High-throughput sequencing was used to establish the differentially expressed circRNA profiles in placental tissues of 5 pairs of PE group and the control group. (2) Real-time quantitative PCR (qRT-PCR) was used to verify the expression levels of 6 differentially expressed circRNAs in placental tissues of PE group and control group. (3) Bioinformatics analysis was used to predict the target miRNA and analyze the co-expressed mRNA to construct a competitive endogenous RNA (ceRNA) network. The differentially expressed circRNAs were analyzed by Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathways. (4) Logistic regression analysis, Pearson correlation and Kendall's tau-b correlation analysis were used to test the correlation between the three differentially expressed circRNAs and the risk of PE and clinical characteristics. (5) circRNA_05393 was selected for subsequent functional study. Small interfering RNA (siRNA) and overexpression plasmid were used to knock down or increase the expression level of circRNA_05393 in trophoblast cell line HTR-8/SVneo cells, respectively. Transwell assay was used to detect the migration and invasion ability of the trophoblasts in vitro. Cell counting kit-8 assay was used to detect the proliferation ability of the trophoblasts. Results: (1) Seventy-two differentially expressed circRNAs were identified by high-throughput sequencing, of which 35 were up-regulated and 37 were down-regulated. (2) qRT-PCR showed that compared with the control group, circRNA_00673 (1.306±0.168 vs 2.059±0.242; t=2.356, P=0.021) and circRNA_07796 (1.275±0.232 vs 1.954±0.230; t=2.018, P=0.047) were significantly increased, while circRNA_05393 (1.846±0.377 vs 0.790±0.094; t=3.138, P=0.002) was significantly decreased. (3) The circRNA-miRNA-mRNA interaction network contained 3 circRNAs, 8 miRNAs and 53 mRNAs. GO functional annotation analysis showed that the biological process was mainly enriched in iron ion homeostasis, membrane depolarization during action potential and neuronal action potential. In terms of cellular components, they were mainly enriched in cytoskeleton and membrane components. In terms of molecular function, they were mainly enriched in the activity of voltage-gated sodium channel and basic amino acid transmembrane transporter. KEGG pathway enrichment analysis showed that mRNAs in the interaction network were mainly enriched in complement and coagulation cascade, glycine, serine and threonine metabolism, p53 signaling pathway and peroxisome proliferators-activated receptors (PPAR) signaling pathway. (4) Logistic regression analysis showed that down-regulation of circRNA_05393 expression was a risk factor for PE (OR=0.044, 95%CI: 0.003-0.596; P=0.019). Correlation analysis showed that circRNA_05393 was significantly correlated with systolic blood pressure and diastolic blood pressure in PE pregnant women (both P<0.05). (5) Knock down or overexpression of circRNA_05393 significantly reduced or increased the migration and invasion abilities of HTR-8/SVneo cells (all P<0.05), but had no significant effect on the ability of tube formation and proliferation (all P>0.05). Conclusions: The construction of circRNA expression profile in placenta and the exploration of circRNA-miRNA-mRNA interaction network provide the possibility to reveal the regulatory mechanism of specific circRNA involved in PE. Inhibition of circRNA_05393 may induce the progression of PE by reducing the migration and invasion of trophoblasts.目的： 通过高通量测序鉴定子痫前期（PE）孕妇胎盘组织中环状RNA（circRNA）的表达谱，构建circRNA-微小RNA（miRNA）-信使RNA（mRNA）相互作用网络，揭示PE发病的相关通路及调控机制。 方法： 收集2019年11月至2021年6月在四川大学华西第二医院分娩的42例PE孕妇（PE组）和30例正常妊娠孕妇（对照组）的临床资料并采集其胎盘组织。（1）采用高通量测序技术建立其中5对PE组和对照组孕妇胎盘组织中的差异表达circRNA谱。（2）实时荧光定量PCR（qRT-PCR）技术验证其中6个差异表达circRNA在PE组和对照组胎盘组织中的表达水平。（3）使用生物信息学方法预测靶miRNA和分析共表达mRNA，构建竞争性内源RNA（ceRNA）网络；并对差异表达circRNA进行基因本体（GO）功能注释分析和京都基因与基因组百科全书（KEGG）通路分析。（4）采用logistic回归分析、Pearson相关、Kendall tau-b相关分析检验3个差异表达circRNA与PE发生风险、临床特征的相关性。（5）选择circRNA_05393进行后续功能研究，使用小分子干扰RNA、过表达质粒分别敲低或提高滋养细胞系HTR-8/SVneo细胞中circRNA_05393的表达水平，采用穿膜小室（transwell小室）体外实验检测细胞的迁移、侵袭能力，活细胞计数法检测细胞的增殖能力，细胞成管实验检测细胞的成管能力。 结果： （1）高通量测序发现了72个差异表达circRNA，其中35个上调，37个下调。（2）qRT-PCR技术检测显示，与对照组比较，PE组孕妇胎盘组织中circRNA_00673（分别为1.306±0.168、2.059±0.242；t=2.356，P=0.021）和circRNA_07796（分别为1.275±0.232、1.954±0.230；t=2.018，P=0.047）的表达水平显著升高，而circRNA_05393（分别为1.846±0.377、0.790±0.094；t=3.138，P=0.002）的表达水平显著降低。（3）circRNA-miRNA-mRNA相互作用网络中包含3个circRNA、8个miRNA和53个mRNA。GO分析显示，生物过程方面主要富集于铁离子稳态、动作电位膜去极化和神经元动作电位等通路，细胞组分方面主要富集于皮质细胞骨架，质膜成分等，分子功能方面主要富集于电压门控钠通道活性、碱性氨基酸跨膜转运蛋白活性等。KEGG信号通路富集分析显示，相互作用网络中的mRNA主要富集于补体和凝血级联反应、甘氨酸、丝氨酸和苏氨酸代谢，p53信号通路，过氧化物酶体增殖物激活受体信号通路。（4）logistic回归分析结果显示，circRNA_05393表达下调是PE发生的危险因素（OR=0.044，95%CI为0.003~0.596；P=0.019）；相关性分析结果显示，circRNA_05393与PE孕妇的收缩压、舒张压显著相关（P均<0.05）。（5）敲低或过表达circRNA_05393显著降低或增加HTR-8/SVneo细胞的迁移、侵袭能力（P均<0.05），但对细胞成管能力、增殖能力无显著影响（P均>0.05）。 结论： 胎盘组织中circRNA表达谱的构建、circRNA-miRNA-mRNA相互作用网络的探索为揭示特定circRNA在PE发生中参与的调控机制提供了可能。抑制circRNA_05393可能通过减少滋养细胞的迁移和侵袭来参与PE的进展。.