SnRNA Sequencing Defines Signaling by RBC-Derived Extracellular Vesicles in the Murine Heart

Extracellular vesicles (EVs) are thought to mediate intercellular signaling by transferring their cargo to recipient cells. Red blood cell (RBC)-derived EVs constitute a significant proportion of circulating EVs and have been implicated in regulating immune responses. Here, we describe the use of a transgenic mouse model for fluorescence-based mapping of RBC-EV recipient cells to assess the functional role of this intercellular signaling mechanism in the pathogenesis of ventricular remodeling after ischemic injury. In this model of ischemic heart failure, we detected an increase in RBC-EV-targeted cardiomyocytes in the heart by fluorescent-based mapping. Single cell nuclear RNA sequencing of the heart revealed a complex landscape of cardiac cells targeted by RBC-EVs, suggesting enriched expression of genes implicated in cell proliferation and metabolism pathways compared to non-targeted cells. Correspondingly, cardiomyocytes targeted by RBC-EVs are more likely to express cellular markers of DNA synthesis and proliferation, suggesting the functional significance of EV-mediated signaling. In conclusion, our mouse model for mapping of EV-recipient cells reveals a complex network of RBC-EV mediated intercellular communication in ischemic heart failure and suggests a functional role for this mode of intercellular signaling.

细胞外囊泡（Extracellular vesicles, EVs）被认为可通过将自身内容物转移至受体细胞，介导细胞间信号传导。红细胞（Red blood cell, RBC）衍生的细胞外囊泡占循环细胞外囊泡的可观比例，且已被证实参与免疫应答的调控。本研究构建了一种可通过荧光成像定位红细胞衍生EVs受体细胞的转基因小鼠模型，用以探究该细胞间信号传导机制在缺血性损伤后心室重构发病进程中的功能作用。在该缺血性心力衰竭模型中，研究人员通过荧光定位成像检测到心脏内靶向红细胞衍生EVs的心肌细胞数量显著增多。对心脏组织开展单细胞核RNA测序后，结果揭示了红细胞衍生EVs所靶向的心脏细胞的复杂转录图谱：相较于未被靶向的细胞，此类靶向细胞中涉及细胞增殖与代谢通路的基因表达显著富集。相应地，被红细胞衍生EVs靶向的心肌细胞更易表达DNA合成与细胞增殖的细胞标志物，这提示EV介导的信号传导具有重要功能意义。综上，本研究所建立的EV受体细胞定位小鼠模型揭示了缺血性心力衰竭中红细胞衍生EVs介导的细胞间通讯的复杂网络，并表明该细胞间信号传导模式具备功能性作用。