Xu Yingjie, Zhang Ke, Sun Changqun, Zhang Qi, Li Bingxin, Yuan Yongjie, Wang Jie, Zhang Jintong, Chang Yajie, Wang Shu, Li Jia
Department of Cardiology, the First Affiliated Hospital, Harbin Medical University, Harbin, China.
Department of Cardiology, the First Affiliated Hospital, Harbin Medical University, Harbin, China.
Mol Immunol. 2025 Aug;184:1-12. doi: 10.1016/j.molimm.2025.05.022. Epub 2025 Jun 2.
The regulation of M1/M2 macrophage phenotypic conversion is an effective therapeutic strategy for post-myocardial infarction (MI). Serum Amyloid A1 (SAA1) is an acute-phase protein that plays an important role in regulating inflammatory responses. However, its function in modulating macrophage polarization post-MI remains unclear.
To achieve macrophage-specific manipulation of SAA1 expression in vivo, adeno-associated virus 9 (AAV9) vectors driven by a macrophage-specific promoter (F4/80) were used to either knockdown (AAV9-F4/80-sh-SAA1) or overexpress (AAV9-F4/80-SAA1) SAA1. Two weeks after the virus injection, mice underwent MI and ischemia-reperfusion (I/R) surgery. Each group included six mice. Immunofluorescence (IF), western blotting, and quantitative real-time polymerase chain reaction were performed to explore the mechanisms underlying SAA1-induced macrophage polarization and cardiac injury after MI and I/R. SAA1 was overexpressed and knocked down in lipopolysaccharide-stimulated bone marrow-derived macrophages in vitro using plasmids and siRNA. IF, western blotting, and quantitative real-time polymerase chain reaction were used to measure macrophage polarization and inflammatory responses.
We detected a significant increase in SAA1 levels in human and mouse peripheral blood mononuclear cells after MI and I/R. Following SAA1 knockout, left ventricular ejection fraction (64.33 ± 2.35 % versus 40.97 ± 8.36 %) was significantly improved and infarcted size (93.95 ± 3.79 % versus 29.76 ± 17.05 %) was markedly reduced in MI+AAV-9-F4/80-Sh-SAA1 compared with MI+AAV-9-F4/80-Sh-NC. Similarly, the accumulation of M1 macrophages in the infarcted tissues was reduced by SAA1 deletion. Mechanistically, these effects were partially mediated by inhibition of via the p38 MAPK signaling pathway.
SAA1 activated the p38 MAPK pathway to contribute to macrophage polarization and the release of inflammatory factors and subsequently exacerbated cardiac injury and inflammatory response post-MI and I/R.
M1/M2巨噬细胞表型转化的调控是心肌梗死后（MI）一种有效的治疗策略。血清淀粉样蛋白A1（SAA1）是一种急性期蛋白，在调节炎症反应中起重要作用。然而，其在心肌梗死后调节巨噬细胞极化中的功能仍不清楚。
为了在体内实现对SAA1表达的巨噬细胞特异性操控，使用由巨噬细胞特异性启动子（F4/80）驱动的腺相关病毒9（AAV9）载体来敲低（AAV9-F4/80-sh-SAA1）或过表达（AAV9-F4/80-SAA1）SAA1。病毒注射两周后，小鼠接受心肌梗死和缺血再灌注（I/R）手术。每组包括6只小鼠。进行免疫荧光（IF）、蛋白质免疫印迹法和定量实时聚合酶链反应，以探究心肌梗死和I/R后SAA1诱导巨噬细胞极化和心脏损伤的潜在机制。在体外使用质粒和小干扰RNA在脂多糖刺激的骨髓来源巨噬细胞中过表达和敲低SAA1。使用IF、蛋白质免疫印迹法和定量实时聚合酶链反应来检测巨噬细胞极化和炎症反应。
我们检测到心肌梗死和I/R后人和小鼠外周血单个核细胞中SAA1水平显著升高。与MI+AAV-9-F4/80-Sh-NC相比，在MI+AAV-9-F4/80-Sh-SAA1中，敲除SAA1后左心室射血分数（64.33±2.35%对40.97±8.36%）显著改善，梗死面积（93.95±3.79%对29.76±17.05%）明显减小。同样，SAA1缺失减少了梗死组织中M1巨噬细胞的积聚。机制上，这些作用部分是通过抑制p38丝裂原活化蛋白激酶信号通路介导的。
SAA1激活p38丝裂原活化蛋白激酶通路，促进巨噬细胞极化和炎症因子释放，进而加重心肌梗死后和I/R后的心脏损伤和炎症反应。
