Department of Cell and Molecular Biology, Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, School of Life Science and Technology, China Pharmaceutical University, Nanjing, P.R. China.
FASEB J. 2024 Aug 15;38(15):e23857. doi: 10.1096/fj.202400639R.
Atherosclerotic plaque formation is largely attributed to the impaired efferocytosis, which is known to be associated with the pathologic upregulation of cluster of differentiation 47 (CD47), a key antiphagocytic molecule. By gene expression omnibus (GEO) datasets analysis, we identified that four miRNAs are aberrantly downregulated in atherosclerosis, coronary artery disease, and obesity. Of them, hsa-miR-299-3p (miR-299-3p) was predicted to target the 3'UTR of human CD47 mRNA by bioinformatics analysis. Further, we demonstrated that miR-299-3p negatively regulates CD47 expression by binding to the target sequence "CCCACAU" in the 3'UTR of CD47 mRNA through luciferase reporter assay and site-directed mutagenesis. Additionally, we found that miR-299-3p was downregulated by ~32% in foam cells in response to oxidized low-density lipoprotein (ox-LDL) stimulation, thus upregulating CD47 and contributing to the impaired efferocytosis. Whereas, restoration of miR-299-3p reversed the ox-LDL-induced upregulation of CD47, thereby facilitating efferocytosis. In high-fat diet (HFD) fed ApoE mice, we discovered that miR-299-3p was downregulated thus leading to upregulation of CD47 in abdominal aorta. Conversely, miR-299-3p restoration potently suppressed HFD-induced upregulation of CD47 and promoted phagocytosis of foam cells by macrophages in atherosclerotic plaques, thereby reducing necrotic core, increasing plaque stability, and mitigating atherosclerosis. Conclusively, we identify miR-299-3p as a negative regulator of CD47, and reveal a molecular mechanism whereby the ox-LDL-induced downregulation of miR-299-3p leads to the upregulation of CD47 in foam cells thus contributing to the impaired efferocytosis in atherosclerosis, and propose miR-299-3p can potentially serve as an inhibitor of CD47 to promote efferocytosis and ameliorate atherosclerosis.
动脉粥样硬化斑块的形成在很大程度上归因于吞噬作用受损,已知吞噬作用受损与分化群 47(CD47)的病理性上调有关,CD47 是一种关键的抗吞噬分子。通过基因表达综合数据库(GEO)数据集分析,我们发现四种 miRNA 在动脉粥样硬化、冠心病和肥胖症中异常下调。其中,hsa-miR-299-3p(miR-299-3p)通过生物信息学分析被预测为靶向人类 CD47 mRNA 的 3'UTR。进一步,我们通过荧光素酶报告基因检测和定点突变证实,miR-299-3p 通过结合 CD47 mRNA 3'UTR 上的靶序列“CCCACAU”负调控 CD47 的表达。此外,我们发现 miR-299-3p 在氧化低密度脂蛋白(ox-LDL)刺激的泡沫细胞中下调约 32%,从而上调 CD47,导致吞噬作用受损。而 miR-299-3p 的恢复则逆转了 ox-LDL 诱导的 CD47 上调,从而促进了吞噬作用。在高脂肪饮食(HFD)喂养的 ApoE 小鼠中,我们发现 miR-299-3p 下调导致腹主动脉 CD47 上调。相反,miR-299-3p 的恢复强烈抑制 HFD 诱导的 CD47 上调,并促进泡沫细胞被斑块中的巨噬细胞吞噬,从而减少坏死核心,增加斑块稳定性,减轻动脉粥样硬化。总之,我们确定 miR-299-3p 是 CD47 的负调节剂,并揭示了一种分子机制,即 ox-LDL 诱导的 miR-299-3p 下调导致泡沫细胞中 CD47 的上调,从而导致动脉粥样硬化中吞噬作用受损,并提出 miR-299-3p 可作为 CD47 的抑制剂,以促进吞噬作用并改善动脉粥样硬化。