Extracellular vesicles (EVs) are abundant, lipid‐enclosed vectors that contain nucleic acids and proteins, they can be secreted from donor cells and freely circulate, and they can be engulfed by recipient cells thus enabling systemic communication between heterotypic cell types. However, genetic tools for labeling, isolating, and auditing cell type‐specific EVs in vivo, without prior in vitro manipulation, are lacking. We have used CRISPR‐Cas9‐mediated genome editing to generate mice bearing a CD63‐emGFP^{loxP/stop/loxP} knock‐in cassette that enables the specific labeling of circulating CD63⁺ vesicles from any cell type when crossed with lineage‐specific Cre recombinase driver mice. As proof‐of‐principle, we have crossed these mice with Cdh5‐Cre^ERT2 mice to generate CD63^emGFP+ vasculature. Using these mice, we show that developing vasculature is marked with emerald GFP (emGFP) following tamoxifen administration to pregnant females. In adult mice, quiescent vasculature and angiogenic vasculature (in tumors) is also marked with emGFP. Moreover, whole plasma‐purified EVs contain a subpopulation of emGFP⁺ vesicles that are derived from the endothelium, co‐express additional EV (e.g., CD9 and CD81) and endothelial cell (e.g., CD105) markers, and they harbor specific miRNAs (e.g., miR‐126, miR‐30c, and miR‐125b). This new mouse strain should be a useful genetic tool for generating cell type‐specific, CD63⁺ EVs that freely circulate in serum and can subsequently be isolated and characterized using standard methodologies.

中文翻译：

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记者小鼠，用于在体内分离和审核特定于细胞类型的细胞外囊泡。

细胞外囊泡（EVs）是丰富的，脂质封闭的载体，包含核酸和蛋白质，可以从供体细胞中分泌出来并自由循环，并且可以被受体细胞吞噬，从而实现异型细胞类型之间的系统性通讯。但是，缺乏无需事先进行体外操作即可在体内标记，分离和审核特定细胞类型电动汽车的遗传工具。我们已经使用CRISPR‐Cas9介导的基因组编辑来生成带有CD63‐emGFP ^{loxP / stop / loxP}敲入盒的小鼠，当与谱系特异性Cre重组酶驱动程序杂交时，该盒能够特异性标记任何细胞类型的循环CD63 ⁺囊泡老鼠。作为原理证明，我们已经将这些小鼠与Cdh5-Cre杂交^ERT2小鼠产生CD63 ^{emGFP +}脉管系统。使用这些小鼠，我们显示了他莫昔芬施用给怀孕的雌性后，发育中的脉管系统标记有翡翠GFP（emGFP）。在成年小鼠中，静止的脉管系统和血管生成的脉管系统（在肿瘤中）也用emGFP标记。此外，整个血浆纯化的电动汽车包含源自内皮的emGFP ⁺囊泡亚群，共表达其他电动汽车（例如CD9和CD81）和内皮细胞（例如CD105）标记，并且它们带有特定的miRNA（例如，miR‐126，miR‐30c和miR‐125b）。这种新的小鼠品系应该是生成特定细胞类型CD63 ⁺的有用遗传工具 在血清中自由循环的电动汽车，随后可以使用标准方法进行分离和表征。