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丝氨酸/苏氨酸蛋白激酶4抑制剂改善心肌梗死后心脏重塑

Mammalian STE20-like protein kinase 4 inhibitor improves post-myocardial infarction cardiac remodeling

  • 摘要:
    目的 探讨丝氨酸/苏氨酸蛋白激酶4(serine/threonine protein kinase 4; mammalian STE20-like protein kinase 4, MST4)在心肌梗死(myocardial infarction, MI)中的作用及其分子机制。
    方法 采用Western印迹检测4例MI患者及4例健康对照者外周血单个核细胞(peripheral blood mononuclear cell, PBMC)中的MST4表达。通过免疫荧光染色比较MI患者心脏缺血区与远端非缺血区的MST4与巨噬细胞共表达情况。构建小鼠MI模型,分为MST4功能抑制(Hesperadin处理)组与对照组(每组12只),利用超声心动图评估处理后心功能改善情况;采用Masson染色观察MI后心脏胶原沉积情况;采用ELISA测定外周血N末端脑钠肽前体(N-terminal pro-brain natriuretic peptide, NT-proBNP)水平。进一步在体外构建MST4功能抑制的骨髓来源巨噬细胞(bone marrow-derived macrophage, BMDM)模型,应用免疫荧光染色检测修复型巨噬细胞标志物精氨酸酶1(arginase 1, Arg1)水平,并利用RT-qPCR检测修复型巨噬细胞相关基因的表达变化。采用Western印迹检测巨噬细胞丝裂原活化蛋白激酶(mitogen-activated protein kinase, MAPK)通路相关蛋白的活化状态。
    结果 与健康对照相比,MST4在MI患者PBMC中表达升高(P<0.000 1),在缺血组织中与CD68+巨噬细胞高度共定位。小鼠MI模型中,与对照组相比,Hesperadin处理组左心室射血分数明显升高(P<0.05),F4/80+巨噬细胞总量无明显变化,外周血NT-proBNP水平降低(P<0.000 1)。体外实验表明,抑制MST4可上调BMDM中修复型巨噬细胞相关基因表达,同时下调MAPK通路蛋白的磷酸化(P<0.05)。
    结论 抑制MST4功能可通过调控MAPK通路诱导巨噬细胞向修复型转化,进而能改善MI后心脏重构和预后。

     

    Abstract:
    Objective To explore the role of serine/threonine protein kinase 4 (mammalian STE20-like protein kinase 4, MST4) in myocardial infarction (MI) and the underlying molecular mechanisms.
    Methods Western blot was performed to assess MST4 expression in peripheral blood mononuclear cells (PBMCs) from four MI patients and four healthy controls. Immunofluorescence staining was used to compare the co-expression of MST4 and macrophages in ischemic regions and non-ischemic regions in myocardial tissues from MI patients. The mouse models of MI were established and divided into an MST4 functional inhibition (treated with Hesperadin) group and a control group ( 12 mice in each group), and cardiac function of model was evaluated by echocardiography; Masson’s trichrome staining was employed to assess cardiac collagen deposition post-MI, and peripheral blood N-terminal pro-brain natriuretic peptide (NT-proBNP) level was measured using ELISA. Further, MST4-inhibited bone marrow-derived macrophages (BMDMs) were constructed in vitro, and immunofluorescence was used to detect the expression of the reparative macrophage marker arginase 1 (Arg1), and RT-qPCR was employed to examine changes in the expression of genes associated with reparative macrophages. Western blot analysis was performed to evaluate the activation status of mitogen-activated protein kinase (MAPK) pathway-related proteins.
    Results MST4 expression was significantly increased in PBMCs from patients with MI and co-localized with CD68+ macrophages in ischemic cardiomyopathy tissues (P<0.000 1). In the mouse models of MI, compared with control group, Hesperadin group had increased left ventricular ejection fraction (P<0.05), lower peripheral blood NT-proBNP level (P<0.000 1), and did not alter total F4/80+ macrophage abundance. In vitro, MST4 inhibition promoted reparative macrophage-associated gene expression and suppressed protein phosphorylation in MAPK pathway (P<0.05).
    Conclusions Inhibition of MST4 promotes macrophage polarization toward a reparative phenotype through modulation of MAPK pathway, thereby improving post-MI cardiac remodeling and outcome.

     

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