Laboratory of Neurobiology and Stem Cells, Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1524 - Room 431, 05508-000,, Sao Paulo, Brazil.
International Research Center, A.C. Camargo Cancer Center, 02056-070, Sao Paulo, Brazil.
Stem Cell Rev Rep. 2018 Apr;14(2):262-276. doi: 10.1007/s12015-017-9776-7.
Extracellular vesicles (EVs) released by mouse embryonic stem cells (mESCs) are considered a source of bioactive molecules that modulate their microenvironment by acting on intercellular communication. Either intracellular endosomal machinery or their derived EVs have been considered a relevant system of signal circuits processing. Herein, we show that these features are found in mESCs. Ultrastructural analysis revealed structures and organelles of the endosomal system such as coated pits and endocytosis-related vesicles, prominent rough endoplasmic reticulum and Golgi apparatus, and multivesicular bodies (MVBs) containing either few or many intraluminal vesicles (ILVs) that could be released as exosomes to extracellular milieu. Besides, budding vesicles shed from the plasma membrane to the extracellular space is suggestive of microvesicle biogenesis in mESCs. mESCs and mouse blastocyst express specific markers of the Endosomal Sorting Complex Required for Transport (ESCRT) system. Ultrastructural analysis and Nanoparticle Tracking Analysis (NTA) of isolated EVs revealed a heterogeneous population of exosomes and microvesicles released by mESCs. These vesicles contain Wnt10b and the Notch ligand Delta-like 4 (DLL4) and also the co-chaperone stress inducible protein 1 (STI1) and its partner Hsp90. Wnt10b and Dll4 colocalize with EVs biogenesis markers in mESCs. Overall, the present study supports the function of the mESCs endocytic network and their EVs as players in stem cell biology.
小鼠胚胎干细胞（mESCs）释放的细胞外囊泡（EVs）被认为是生物活性分子的来源，这些分子通过作用于细胞间通讯来调节其微环境。细胞内内体机制或其衍生的 EVs 被认为是信号转导处理的相关系统。本文中，我们展示了这些特征在 mESCs 中存在。超微结构分析显示了内体系统的结构和细胞器，如有被小窝和内吞相关囊泡、发达的粗面内质网和高尔基体，以及含有少量或大量腔内囊泡（ILVs）的多泡体（MVBs），这些 ILVs 可以作为外泌体释放到细胞外环境中。此外，从质膜到细胞外空间出芽的囊泡提示 mESCs 中存在微泡的生物发生。mESCs 和小鼠囊胚表达内体分选复合物必需的运输（ESCRT）系统的特异性标记物。分离的 EVs 的超微结构分析和纳米颗粒跟踪分析（NTA）显示了 mESCs 释放的异质群体的外泌体和微泡。这些囊泡含有 Wnt10b 和 Notch 配体 Delta-like 4（DLL4），以及伴侣蛋白应激诱导蛋白 1（STI1）及其伴侣热休克蛋白 90（Hsp90）。Wnt10b 和 Dll4 与 mESCs 中 EVs 生物发生标记物共定位。总的来说，本研究支持 mESCs 内吞网络及其 EVs 作为干细胞生物学中参与者的功能。
