Du Heng, You Xintong, Zhang Jiahe, Liu Siqi, Zhou Yanan, Wang Yuhan, Yang Chaofan, Meng Yanan, Liu Xu, Zhang Hao, Li Yujing, Shen Jianghua, Yuan Hailong, Xu Pengfei, He Chuting, Xiao Yi, Gao Zeyu, Zang Jingyi, Wei Tuo, Song Moshi
State Key Laboratory of Organ Regeneration and Reconstruction, Institute of Zoology, Chinese Academy of Sciences, Beijing, China (H.D., X.Y., J. Zhang, S.L., Y.Z., Y.W., C.Y., Y.M., X.L., H.Z., Y.L., J.S., H.Y., P.X., C.H., Y.X., Z.G., J. Zang, T.W., M.S.).
Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, China (H.D., X.Y., J. Zhang, S.L., Y.Z., Y.W., C.Y., Y.M., X.L., H.Z., Y.L., J.S., H.Y., P.X., C.H., Y.X., Z.G., J. Zang, T.W., M.S.).
Circ Res. 2025 Aug 29;137(6):846-859. doi: 10.1161/CIRCRESAHA.125.326716. Epub 2025 Aug 5.
Myocardial ischemia-reperfusion (I/R) injury induces myocardial fibrosis that compromises cardiac function and electrical conduction, yet current clinical options remain inadequate. To address this unmet need, we explored macrophage-targeted lipid nanoparticles (LNPs) encapsulating FAP CAR (FAP [fibroblast activation protein]-targeted chimeric antigen receptor) mRNA for in vivo generation of FAP CAR macrophages and evaluated their therapeutic potential in reducing myocardial fibrosis and improving cardiac function after myocardial I/R injury.
We formulated 1,2-dioleoyl-sn-glycero-3-phospho-l-serine-doping ALC-0315 (an ionizable lipid) LNP to deliver FAP CAR mRNA to generate FAP CAR macrophages. The platform was first validated in vitro by assessing phagocytosis of FAP-overexpressing fibroblasts by these macrophages. For in vivo evaluation, C57BL/6J mice subjected to I/R injury received intravenous administration of PBS, control LNPs, or LNP-FAP CAR (LNPs encapsulating mRNA encoding a FAP-targeting CAR). Comprehensive analyses included tracking the biodistribution of the resultant FAP CAR macrophages, quantitative measurement of fibrosis reduction, assessment of cardiac function by echocardiography, and safety evaluations.
LNP-FAP CAR successfully generated functional FAP CAR macrophages that demonstrated phagocytosis ability toward FAP-positive fibroblasts in vitro. In vivo studies revealed that intravenous delivery of LNP-FAP CAR generated functional FAP CAR macrophages that selectively engaged and phagocytosed activated cardiac fibroblasts in I/R mouse hearts. This targeted cell clearance translated to a significant reduction in the number of activated cardiac fibroblasts and the extent of myocardial fibrosis, as well as marked improvement in cardiac function without detectable toxicities. Notably, these effects were achievable even when intervention was delayed for up to 2 weeks post-I/R.
Our study demonstrates that FAP CAR macrophages generated in vivo by LNP-FAP CAR treatment effectively mitigate cardiac fibrosis and improve heart function after I/R injury, with lasting benefits and no observed toxicity. This safe and adaptable platform offers a promising treatment strategy for myocardial I/R injury and holds potential for treating other fibrotic heart diseases.
心肌缺血再灌注（I/R）损伤会引发心肌纤维化，损害心脏功能和电传导，然而目前的临床治疗选择仍不充分。为满足这一未被满足的需求，我们探索了包裹FAP CAR（靶向成纤维细胞活化蛋白的嵌合抗原受体）mRNA的巨噬细胞靶向脂质纳米颗粒（LNPs），用于在体内生成FAP CAR巨噬细胞，并评估它们在减少心肌纤维化和改善心肌I/R损伤后心脏功能方面的治疗潜力。
我们制备了1,2-二油酰基-sn-甘油-3-磷酸-L-丝氨酸掺杂ALC-0315（一种可电离脂质）的LNP，以递送FAP CAR mRNA来生成FAP CAR巨噬细胞。该平台首先在体外通过评估这些巨噬细胞对过表达FAP的成纤维细胞的吞噬作用进行验证。对于体内评估，遭受I/R损伤的C57BL/6J小鼠接受静脉注射PBS、对照LNPs或LNP-FAP CAR（包裹编码靶向FAP的CAR的mRNA的LNPs）。综合分析包括追踪所产生的FAP CAR巨噬细胞的生物分布、纤维化减少的定量测量、通过超声心动图评估心脏功能以及安全性评估。
LNP-FAP CAR成功生成了功能性FAP CAR巨噬细胞，这些巨噬细胞在体外对FAP阳性成纤维细胞表现出吞噬能力。体内研究表明，静脉注射LNP-FAP CAR可生成功能性FAP CAR巨噬细胞，它们在I/R小鼠心脏中选择性地与活化的心脏成纤维细胞结合并吞噬。这种靶向细胞清除导致活化心脏成纤维细胞数量和心肌纤维化程度显著降低，心脏功能也有明显改善，且未检测到毒性。值得注意的是，即使在I/R后延迟长达2周进行干预，这些效果仍然可以实现。
我们的研究表明，通过LNP-FAP CAR治疗在体内生成的FAP CAR巨噬细胞可有效减轻I/R损伤后的心脏纤维化并改善心脏功能，具有持久益处且未观察到毒性。这个安全且适应性强的平台为心肌I/R损伤提供了一种有前景的治疗策略，并且在治疗其他纤维化性心脏病方面具有潜力。
