Department of Cardiology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Charite Centrum 11, Hindenburgdamm 30, Berlin, Germany.
Institute for Pharmacology, Universitätsmedizin Greifswald, Felix-Hausdorff-Strasse 3, Greifswald, Germany.
Cardiovasc Res. 2019 Nov 1;115(13):1886-1906. doi: 10.1093/cvr/cvz085.
Inflammation is a key driver of atherosclerosis and myocardial infarction (MI), and beyond proteins and microRNAs (miRs), long noncoding RNAs (lncRNAs) have been implicated in inflammation control. To obtain further information on the possible role of lncRNAs in the context of atherosclerosis, we obtained comprehensive transcriptome maps of circulating immune cells (peripheral blood mononuclear cells, PBMCs) of early onset MI patients. One lncRNA significantly suppressed in post-MI patients was further investigated in a murine knockout model.
Individual RNA-sequencing (RNA-seq) was conducted on PBMCs from 28 post-MI patients with a history of MI at age ≤50 years and stable disease ≥3 months before study participation, and from 31 healthy individuals without manifest cardiovascular disease or family history of MI as controls. RNA-seq revealed deregulated protein-coding transcripts and lncRNAs in post-MI PBMCs, among which nuclear enriched abundant transcript (NEAT1) was the most highly expressed lncRNA, and the only one significantly suppressed in patients. Multivariate statistical analysis of validation cohorts of 106 post-MI patients and 85 controls indicated that the PBMC NEAT1 levels were influenced (P = 0.001) by post-MI status independent of statin intake, left ventricular ejection fraction, low-density lipoprotein or high-density lipoprotein cholesterol, or age. We investigated NEAT1-/- mice as a model of NEAT1 deficiency to evaluate if NEAT1 depletion may directly and causally alter immune regulation. RNA-seq of NEAT1-/- splenocytes identified disturbed expression and regulation of chemokines/receptors, innate immunity genes, tumour necrosis factor (TNF) and caspases, and increased production of reactive oxygen species (ROS) under baseline conditions. NEAT1-/- spleen displayed anomalous Treg and TH cell differentiation. NEAT1-/- bone marrow-derived macrophages (BMDMs) displayed altered transcriptomes with disturbed chemokine/chemokine receptor expression, increased baseline phagocytosis (P < 0.0001), and attenuated proliferation (P = 0.0013). NEAT1-/- BMDMs responded to LPS with increased (P < 0.0001) ROS production and disturbed phagocytic activity (P = 0.0318). Monocyte-macrophage differentiation was deregulated in NEAT1-/- bone marrow and blood. NEAT1-/- mice displayed aortic wall CD68+ cell infiltration, and there was evidence of myocardial inflammation which could lead to severe and potentially life-threatening structural damage in some of these animals.
The study indicates distinctive alterations of lncRNA expression in post-MI patient PBMCs. Regarding the monocyte-enriched NEAT1 suppressed in post-MI patients, the data from NEAT1-/- mice identify NEAT1 as a novel lncRNA-type immunoregulator affecting monocyte-macrophage functions and T cell differentiation. NEAT1 is part of a molecular circuit also involving several chemokines and interleukins persistently deregulated post-MI. Individual profiling of this circuit may contribute to identify high-risk patients likely to benefit from immunomodulatory therapies. It also appears reasonable to look for new therapeutic targets within this circuit.
炎症是动脉粥样硬化和心肌梗死（MI）的关键驱动因素，除了蛋白质和 microRNAs（miRs）外，长链非编码 RNA（lncRNAs）也被认为在炎症控制中发挥作用。为了进一步了解 lncRNAs 在动脉粥样硬化背景下的可能作用，我们获得了早发性 MI 患者循环免疫细胞（外周血单核细胞，PBMCs）的综合转录组图谱。在 MI 患者中显著下调的一个 lncRNA 在小鼠敲除模型中进一步进行了研究。
对 28 名 MI 病史≤50 岁且研究参与前稳定疾病≥3 个月的 MI 后患者的 PBMCs 进行个体 RNA 测序（RNA-seq），并对 31 名无明显心血管疾病或 MI 家族史的健康个体作为对照进行了研究。RNA-seq 显示 MI 后 PBMCs 中存在失调的蛋白编码转录物和 lncRNAs，其中核丰富丰富转录物（NEAT1）是表达最高的 lncRNA，并且在患者中明显受到抑制。对 106 名 MI 后患者和 85 名对照的验证队列进行多元统计分析表明，PBMC 中 NEAT1 水平受 MI 状态的影响（P=0.001），与他汀类药物摄入、左心室射血分数、低密度脂蛋白或高密度脂蛋白胆固醇或年龄无关。我们研究了 NEAT1-/- 小鼠作为 NEAT1 缺乏的模型，以评估 NEAT1 耗竭是否可能直接和因果地改变免疫调节。NEAT1-/- 脾细胞的 RNA-seq 确定了在基线条件下，趋化因子/受体、先天免疫基因、肿瘤坏死因子（TNF）和半胱天冬酶的表达和调节紊乱，以及活性氧（ROS）的产生增加。NEAT1-/- 脾脏显示异常的 Treg 和 TH 细胞分化。NEAT1-/- 骨髓来源的巨噬细胞（BMDMs）显示出改变的转录组，表现为趋化因子/趋化因子受体表达紊乱、基础吞噬作用增加（P<0.0001）和增殖减弱（P=0.0013）。NEAT1-/-BMDMs 对 LPS 的反应表现为 ROS 产生增加（P<0.0001）和吞噬活性紊乱（P=0.0318）。NEAT1-/- 骨髓和血液中的单核细胞-巨噬细胞分化失调。NEAT1-/- 小鼠显示主动脉壁 CD68+细胞浸润，并且有心肌炎症的证据，这可能导致其中一些动物发生严重且潜在危及生命的结构损伤。
该研究表明 MI 后患者 PBMCs 中存在独特的 lncRNA 表达改变。关于在 MI 后患者中富集的单核细胞下调的 NEAT1，NEAT1-/- 小鼠的数据确定 NEAT1 是一种新型 lncRNA 免疫调节剂，影响单核细胞-巨噬细胞功能和 T 细胞分化。NEAT1 是分子电路的一部分，该电路还涉及几个持续失调的趋化因子和白细胞介素 post-MI。对该电路进行个体分析可能有助于确定可能受益于免疫调节治疗的高危患者。在该电路中寻找新的治疗靶点也是合理的。
