环状 RNA-Ntrk2 通过作为 miR-296-5p 的海绵吸附体激活 TGF-β1/p38MAPK 通路，从而促进肺动脉高压和血管重构。
Circ-Ntrk2 acts as a miR-296-5p sponge to activate the TGF-β1/p38 MAPK pathway and promote pulmonary hypertension and vascular remodelling.
机构信息
Division of Pulmonary Medicine, Wenzhou Key Laboratory of Interdiscipline and Translational Medicine, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang, China.
State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangdong Key Laboratory of Vascular Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510000, Guangdong, China.
出版信息
Respir Res. 2023 Mar 13;24(1):78. doi: 10.1186/s12931-023-02385-7.
BACKGROUND
Circular RNAs (circRNAs), a novel class of non-coding RNAs, play an important regulatory role in pulmonary arterial hypertension (PAH); however, the specific mechanism is rarely studied. In this study, we aimed to discover functional circRNAs and investigate their effects and mechanisms in hypoxia-induced pulmonary vascular remodelling, a core pathological change in PAH.
METHODS
RNA sequencing was used to illustrate the expression profile of circRNAs in hypoxic PAH. Bioinformatics, Sanger sequencing, and quantitative real-time PCR were used to identify the ring-forming characteristics of RNA and analyse its expression. Then, we established a hypoxia-induced PAH mouse model to evaluate circRNA function in PAH by echocardiography and hemodynamic measurements. Moreover, microRNA target gene database screening, fluorescence in situ hybridisation, luciferase reporter gene detection, and western blotting were used to explore the mechanism of circRNAs.
RESULTS
RNA sequencing identified 432 differentially expressed circRNAs in mouse hypoxic lung tissues. Our results indicated that circ-Ntrk2 is a stable cytoplasmic circRNA derived from Ntrk2 mRNA and frequently upregulated in hypoxic lung tissue. We further found that circ-Ntrk2 sponges miR-296-5p and miR-296-5p can bind to the 3'-untranslated region of transforming growth factor-β1 (TGF-β1) mRNA, thereby attenuating TGF-β1 translation. Through gene knockout or exogenous expression, we demonstrated that circ-Ntrk2 could promote PAH and vascular remodelling. Moreover, we verified that miR-296-5p overexpression alleviated pulmonary vascular remodelling and improved PAH through the TGF-β1/p38 MAPK pathway.
CONCLUSIONS
We identified a new circRNA (circ-Ntrk2) and explored its function and mechanism in PAH, thereby establishing potential targets for the diagnosis and treatment of PAH. Furthermore, our study contributes to the understanding of circRNA in relation to PAH.
背景
环状 RNA（circRNAs）是一类新型的非编码 RNA，在肺动脉高压（PAH）中发挥重要的调控作用；然而，其具体机制很少被研究。在这项研究中，我们旨在发现功能性 circRNAs，并研究它们在缺氧诱导的肺血管重构中的作用和机制，这是 PAH 的核心病理改变。
方法
使用 RNA 测序来阐明缺氧性 PAH 中 circRNAs 的表达谱。生物信息学、Sanger 测序和实时定量 PCR 用于鉴定 RNA 的环形成特征并分析其表达。然后，我们建立了缺氧诱导的 PAH 小鼠模型，通过超声心动图和血流动力学测量来评估 circRNA 在 PAH 中的功能。此外，使用 microRNA 靶基因数据库筛选、荧光原位杂交、荧光素酶报告基因检测和 Western blot 来探索 circRNAs 的机制。
结果
RNA 测序鉴定了小鼠缺氧肺组织中 432 个差异表达的 circRNAs。我们的结果表明，circ-Ntrk2 是一种源自 Ntrk2 mRNA 的稳定细胞质 circRNA，在缺氧肺组织中频繁上调。我们进一步发现，circ-Ntrk2 作为 miR-296-5p 的海绵体并结合 TGF-β1 mRNA 的 3'-非翻译区，从而减弱 TGF-β1 的翻译。通过基因敲除或外源性表达，我们证明了 circ-Ntrk2 可以促进 PAH 和血管重构。此外，我们验证了 miR-296-5p 的过表达通过 TGF-β1/p38 MAPK 途径减轻肺血管重构并改善 PAH。
结论
我们鉴定了一种新的 circRNA（circ-Ntrk2），并研究了其在 PAH 中的功能和机制，从而为 PAH 的诊断和治疗建立了潜在的靶点。此外，我们的研究有助于理解 circRNA 与 PAH 的关系。
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