BACKGROUND Macrophage-driven inflammation critically involves in cardiac injury and repair following myocardial infarction (MI). However, the intrinsic mechanisms that halt the immune response of macrophages, which is critical to preserve homeostasis and effective infarct repair, remain to be fully defined. Here, we aimed to determine the ubiquitination-mediated regulatory effects on averting exaggerated inflammatory responses in cardiac macrophages. METHODS We used transcriptome analysis of mouse cardiac macrophages and bone marrow-derived macrophages to identify the E3 ubiquitin ligase RNF149 (ring finger protein 149) as a modulator of macrophage response to MI. Employing loss-of-function methodologies, bone marrow transplantation approaches, and adenovirus-mediated RNF149 overexpression in macrophages, we elucidated the functional role of RNF149 in MI. We explored the underlying mechanisms through flow cytometry, transcriptome analysis, immunoprecipitation/mass spectrometry analysis, and functional experiments. RNF149 expression was measured in the cardiac tissues of patients with acute MI and healthy controls. RESULTS RNF149 was highly expressed in murine and human cardiac macrophages at the early phase of MI. Knockout of RNF149, transplantation of Rnf149-/- bone marrow, and bone marrow macrophage-specific RNF149-knockdown markedly exacerbated cardiac dysfunction in murine MI models. Conversely, overexpression of RNF149 in macrophages attenuated the ischemia-induced decline in cardiac contractile function. RNF149 deletion increased infiltration of proinflammatory monocytes/macrophages, accompanied by a hastened decline in reparative subsets, leading to aggravation of myocardial apoptosis and impairment of infarct healing. Our data revealed that RNF149 in infiltrated macrophages restricted inflammation by promoting ubiquitylation-dependent proteasomal degradation of IFNGR1 (interferon gamma receptor 1). Loss of IFNGR1 rescued deleterious effects of RNF149 deficiency on MI. We further demonstrated that STAT1 (signal transducer and activator of transcription 1) activation induced Rnf149 transcription, which, in turn, destabilized the IFNGR1 protein to counteract type-II IFN (interferon) signaling, creating a feedback control mechanism to fine-tune macrophage-driven inflammation. CONCLUSIONS These findings highlight the significance of RNF149 as a molecular brake on macrophage response to MI and uncover a macrophage-intrinsic posttranslational mechanism essential for maintaining immune homeostasis and facilitating cardiac repair following MI.

中文翻译：

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RNF149 破坏巨噬细胞中 IFNGR1 的稳定性，有利于梗死后心脏修复。


背景技术巨噬细胞驱动的炎症严重参与心肌梗塞（MI）后的心脏损伤和修复。然而，阻止巨噬细胞免疫反应的内在机制仍有待完全确定，巨噬细胞免疫反应对于保持体内平衡和有效梗塞修复至关重要。在这里，我们的目的是确定泛素化介导的调节作用，以避免心脏巨噬细胞过度炎症反应。方法 我们使用小鼠心脏巨噬细胞和骨髓源性巨噬细胞的转录组分析来鉴定 E3 泛素连接酶 RNF149（环指蛋白 149）作为巨噬细胞对 MI 反应的调节剂。采用功能丧失方法、骨髓移植方法和腺病毒介导的巨噬细胞中 RNF149 过表达，我们阐明了 RNF149 在 MI 中的功能作用。我们通过流式细胞术、转录组分析、免疫沉淀/质谱分析和功能实验探索了潜在的机制。在急性心肌梗死患者和健康对照的心脏组织中测量了 RNF149 的表达。结果 在 MI 早期，RNF149 在小鼠和人类心脏巨噬细胞中高表达。 RNF149 敲除、Rnf149-/- 骨髓移植和骨髓巨噬细胞特异性 RNF149 敲除显着加剧了小鼠 MI 模型中的心功能障碍。相反，巨噬细胞中 RNF149 的过度表达减弱了缺血引起的心脏收缩功能下降。 RNF149缺失增加了促炎单核细胞/巨噬细胞的浸润，伴随着修复亚群的加速下降，导致心肌细胞凋亡加剧和梗塞愈合受损。 我们的数据显示，浸润巨噬细胞中的 RNF149 通过促进 IFNGR1（干扰素γ受体 1）的泛素化依赖性蛋白酶体降解来限制炎症。 IFNGR1 的缺失挽救了 RNF149 缺陷对 MI 的有害影响。我们进一步证明，STAT1（信号转导子和转录激活子 1）激活诱导 Rnf149 转录，进而破坏 IFNGR1 蛋白的稳定性，从而抵消 II 型 IFN（干扰素）信号传导，从而创建反馈控制机制来微调巨噬细胞-驱动的炎症。结论 这些发现强调了 RNF149 作为巨噬细胞对 MI 反应的分子制动器的重要性，并揭示了巨噬细胞固有的翻译后机制，这对于维持免疫稳态和促进 MI 后的心脏修复至关重要。