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Published on: August 3, 2018
miRNA-146a-5p Inhibits Hypoxia-Induced Myocardial Fibrosis Through EndMT
Yan Wang1, Jie Yu2, Chunxia Ou3
1Laboratory of Molecular Cardiology, Department of Cardiology, The First Affiliated Hospital of Kunming Medical University, No. 295 Xichang Rd, Kunming, 650032, Yunnan, China. wangyan@ydyy.cn.
Abstract:
Cardiac Vascular disease particularly myocardial infarction (MI) is a threat to health worldwide. microRNAs (miRNAs) have been shown to regulate myocardial fibrosis. Therefore, it is potential to investigate the mechanism of miRNA and fibrosis following myocardial infarction. Hypoxia human cardiac microvascular endothelial cells (HCMECs) were selected for the vitro experimental model. The miR-146a-5p expression was tested via RT-qPCR. The level of endothelial-to-mesenchymal transition (EndMT) and fibrosis markers were detected by Western blotting and immunofluorescence. Then, the inflammation, cell viability and apoptosis were investigated. The target was predicted by an online database and verified by a dual-luciferase activity assay. An MI mouse model was created to validate that miR-146a-5p regulates cardiac fibrosis in vivo. MI mouse was transfected with miR-146a-5p lentivirus. Subsequently, its effect on cardiac fibrosis of infarcted hearts was assessed by In situ hybridization (ISH), Immunohistochemistry (IHC), Triphenylterazolium chloride (TTC) staining and Masson staining. Herein, we confirmed that miR-146a-5p was down-regulated in hypoxia HCMECs. Overexpression of miR-146a-5p inhibited hypoxia-induced cardiac fibrosis following myocardial infarction by inhibiting EndMT in HCMECs. Thioredoxin-interacting protein (TXNIP) was a target that was negatively regulated by miR-146a-5p. Up-regulation of miR-146a-5p inhibited cardiac fibrosis via regulating EndMT by targeting TXNIP, and it also regulated EndMT to inhibit cardiac fibrosis in vivo.
Insights
MicroRNA-146a-5p, a key regulator, inhibits cardiac fibrosis after myocardial infarction by suppressing endothelial-to-mesenchymal transition. Upregulating miR-146a-5p offers a potential therapeutic strategy for heart disease.
Area of Science:
- Cardiovascular Biology
- Molecular Medicine
- Fibrosis Research
Background:
- Myocardial infarction (MI) poses a global health risk, with cardiac fibrosis exacerbating heart dysfunction.
- MicroRNAs (miRNAs) are implicated in regulating myocardial fibrosis, suggesting potential therapeutic targets.
- Understanding miRNA-mediated mechanisms in post-MI fibrosis is crucial for developing new treatments.
Purpose of the Study:
- To investigate the role of miR-146a-5p in regulating cardiac fibrosis following myocardial infarction.
- To elucidate the mechanism by which miR-146a-5p influences endothelial-to-mesenchymal transition (EndMT) and fibrosis.
- To validate the therapeutic potential of miR-146a-5p in an in vivo myocardial infarction model.
Main Methods:
- Hypoxia-induced human cardiac microvascular endothelial cells (HCMECs) served as an in vitro model.
- miR-146a-5p expression was quantified using RT-qPCR.
- EndMT and fibrosis markers were assessed via Western blotting and immunofluorescence.
- Target validation was performed using a dual-luciferase assay.
- An in vivo MI mouse model was utilized, with miR-146a-5p lentivirus transfection and histological analyses (ISH, IHC, TTC, Masson staining).
Main Results:
- miR-146a-5p expression was significantly downregulated in hypoxia-treated HCMECs.
- Overexpression of miR-146a-5p suppressed hypoxia-induced EndMT and subsequent cardiac fibrosis in vitro.
- Thioredoxin-interacting protein (TXNIP) was identified as a direct target negatively regulated by miR-146a-5p.
- In vivo, miR-146a-5p upregulation attenuated cardiac fibrosis in the infarcted hearts of MI mice.
Conclusions:
- miR-146a-5p plays a protective role against cardiac fibrosis post-myocardial infarction.
- The mechanism involves the inhibition of EndMT through targeting TXNIP.
- Modulating miR-146a-5p represents a promising therapeutic avenue for mitigating cardiac fibrosis and improving outcomes after MI.
