Department of Cardiovascular Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, PR China; Institute of Cardiovascular Diseases, Shanghai Jiao Tong University School of Medicine, Shanghai, PR China.
Department of Cardiovascular Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, PR China; Institute of Cardiovascular Diseases, Shanghai Jiao Tong University School of Medicine, Shanghai, PR China.
EBioMedicine. 2023 Sep;95:104744. doi: 10.1016/j.ebiom.2023.104744. Epub 2023 Aug 8.
Macrophage infiltration and polarization are integral to the progression of heart failure and cardiac fibrosis after ischemia/reperfusion (IR). Interleukin 34 (IL-34) is an inflammatory regulator related to a series of autoimmune diseases. Whether IL-34 mediates inflammatory responses and contributes to cardiac remodeling and heart failure post-IR remains unclear.
IL-34 knock-out mice were used to determine the role of IL-34 on cardiac remodeling after IR surgery. Then, immunofluorescence, flow cytometry assays, and RNA-seq analysis were performed to explore the underlying mechanisms of IL-34-induced macrophage recruitment and polarization, and further heart failure after IR.
By re-analyzing single-cell RNA-seq and single-nucleus RNA-seq data of murine and human ischemic hearts, we showed that IL-34 expression was upregulated after IR. IL-34 knockout mitigated cardiac remodeling, cardiac dysfunction, and fibrosis after IR and vice versa. RNA-seq analysis revealed that IL-34 deletion correlated negatively with immune responses and chemotaxis after IR injury. Consistently, immunofluorescence and flow cytometry assays demonstrated that IL-34 deletion attenuated macrophage recruitment and CCR2+ macrophage polarization. Mechanistically, IL-34 deficiency repressed both the canonical and noncanonical NF-κB signaling pathway, leading to marked reduction of P-IKKβ and P-IκBα kinase levels; downregulation of NF-κB p65, RelB, and p52 expression, which drove the decline in chemokine CCL2 expression. Finally, IL-34 and CCL2 levels were increased in the serum of acute coronary syndrome patients, with a positive correlation between circulating IL-34 and CCL2 levels in clinical patients.
In conclusion, IL-34 sustains NF-κB pathway activation to elicit increased CCL2 expression, which contributes to macrophage recruitment and polarization, and subsequently exacerbates cardiac remodeling and heart failure post-IR. Strategies targeting IL-34-centered immunomodulation may provide new therapeutic approaches to prevent and reverse cardiac remodeling and heart failure in clinical MI patients after percutaneous coronary intervention.
This study was supported by the National Nature Science Foundation of China (81670352 and 81970327 to R T, 82000368 to Q F).
巨噬细胞浸润和极化是缺血/再灌注（IR）后心力衰竭和心脏纤维化进展的关键。白细胞介素 34（IL-34）是一种与一系列自身免疫性疾病相关的炎症调节剂。IL-34 是否调节炎症反应并促进 IR 后心脏重构和心力衰竭尚不清楚。
使用 IL-34 敲除小鼠确定 IL-34 在 IR 手术后心脏重构中的作用。然后，进行免疫荧光、流式细胞术分析和 RNA 测序分析，以探讨 IL-34 诱导的巨噬细胞募集和极化以及进一步的 IR 后心力衰竭的潜在机制。
通过重新分析小鼠和人类缺血性心脏的单细胞 RNA-seq 和单核 RNA-seq 数据，我们显示 IR 后 IL-34 表达上调。IL-34 敲除减轻了 IR 后的心脏重构、心功能障碍和纤维化，反之亦然。RNA 测序分析显示，IL-34 缺失与 IR 损伤后的免疫反应和趋化作用呈负相关。同样，免疫荧光和流式细胞术分析表明，IL-34 缺失可减弱巨噬细胞募集和 CCR2+巨噬细胞极化。在机制上，IL-34 缺乏抑制了经典和非经典 NF-κB 信号通路，导致 P-IKKβ 和 P-IκBα 激酶水平显著降低；NF-κB p65、RelB 和 p52 表达下调，导致趋化因子 CCL2 表达下降。最后，急性冠脉综合征患者的血清中 IL-34 和 CCL2 水平升高，临床患者循环中 IL-34 和 CCL2 水平呈正相关。
总之，IL-34 维持 NF-κB 通路的激活，引起 CCL2 表达增加，促进巨噬细胞募集和极化，进而加重 IR 后心脏重构和心力衰竭。以 IL-34 为中心的免疫调节策略可能为预防和逆转经皮冠状动脉介入治疗后临床 MI 患者的心脏重构和心力衰竭提供新的治疗方法。
本研究得到国家自然科学基金（R T 81670352 和 81970327，Q F 82000368）的支持。
