背景
单核细胞/巨噬细胞在心肌梗死 (MI) 后的炎症和心脏重塑中起关键作用。胆碱能抗炎通路 (CAP) 通过激活单核细胞/巨噬细胞中的 α7 烟碱型乙酰胆碱受体 (α7nAChR) 来调节局部和全身炎症反应。我们研究了 α7nAChR 对 MI 诱导的单核细胞/巨噬细胞募集和极化的影响及其对心脏重塑和功能障碍的贡献。
方法
成年雄性 Sprague Dawley 大鼠接受冠状动脉结扎术，并腹膜内注射 α7nAChR 选择性激动剂 PNU282987 或拮抗剂甲基乌头碱 (MLA)。RAW264.7 细胞用脂多糖 (LPS) + 干扰素-γ (IFN-γ) 刺激，并用 PNU282987、MLA 和 S3I-201（一种 STAT3 抑制剂）处理。心脏功能通过超声心动图评估。Masson 的三色和免疫荧光用于检测心脏纤维化、心肌毛细血管密度和 M1/M2 巨噬细胞。Western blotting检测蛋白表达，流式细胞术检测单核细胞比例。
结果
用 PNU282987 激活 CAP 可显着改善心功能并减少心肌纤维化和 MI 后 28 天死亡率。在 MI 后第 3 天和第 7 天，PNU282987 减少了外周 CD172a + CD43low 单核细胞的百分比和梗死心脏中 M1 巨噬细胞的浸润，而增加了外周 CD172a + CD43high 单核细胞和 M2 巨噬细胞的募集。相反，MLA 发挥了相反的作用。在体外，PNU282987 在 LPS + IFN-γ 刺激的 RAW264.7 细胞中抑制 M1 巨噬细胞极化并促进 M2 巨噬细胞极化。LPS + IFN-γ 刺激的 RAW264.7 细胞中这些 PNU282987 诱导的变化可通过施用 S3I-201 逆转。
结论
激活 α7nAChR 可抑制 MI 期间促炎性单核细胞/巨噬细胞的早期募集，并改善心脏功能和重塑。我们的研究结果提出了一个有前途的治疗靶点，用于调节单核细胞/巨噬细胞表型和促进 MI 后的愈合。
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Activating α7nAChR helps post-myocardial infarction healing by regulating macrophage polarization via the STAT3 signaling pathway
Background
Monocytes/macrophages play critical roles in inflammation and cardiac remodeling following myocardial infarction (MI). The cholinergic anti-inflammatory pathway (CAP) modulates local and systemic inflammatory responses by activating α7 nicotinic acetylcholine receptors (α7nAChR) in monocytes/macrophages. We investigated the effect of α7nAChR on MI-induced monocyte/macrophage recruitment and polarization and its contribution to cardiac remodeling and dysfunction.
Methods
Adult male Sprague Dawley rats underwent coronary ligation and were intraperitoneally injected with the α7nAChR-selective agonist PNU282987 or the antagonist methyllycaconitine (MLA). RAW264.7 cells were stimulated with lipopolysaccharide (LPS) + interferon-gamma (IFN-γ) and treated with PNU282987, MLA, and S3I-201 (a STAT3 inhibitor). Cardiac function was evaluated by echocardiography. Masson’s trichrome and immunofluorescence were used to detect cardiac fibrosis, myocardial capillary density, and M1/M2 macrophages. Western blotting was used to detect protein expression, and the proportion of monocytes was measured using flow cytometry.
Results
Activating the CAP with PNU282987 significantly improved cardiac function and reduced cardiac fibrosis and 28-day mortality after MI. On days 3 and 7 post-MI, PNU282987 reduced the percentage of peripheral CD172a + CD43low monocytes and the infiltration of M1 macrophages in the infarcted hearts, whereas it increased the recruitment of peripheral CD172a + CD43high monocytes and M2 macrophages. Conversely, MLA exerted the opposite effects. In vitro, PNU282987 inhibited M1 macrophage polarization and promoted M2 macrophage polarization in LPS + IFN-γ-stimulated RAW264.7 cells. These PNU282987-induced changes in LPS + IFN-γ-stimulated RAW264.7 cells were reversed by administering S3I-201.
Conclusion
Activating α7nAChR inhibits the early recruitment of pro-inflammatory monocytes/macrophages during MI and improves cardiac function and remodeling. Our findings suggest a promising therapeutic target for regulating monocyte/macrophage phenotypes and promoting healing after MI.
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