Galectin-5 is bound onto the surface of rat reticulocyte exosomes and modulates vesicle uptake by macrophages
Galectin-5 is bound onto the surface of rat reticulocyte exosomes and modulates vesicle uptake by macrophages
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DOI：
10.1182/blood-2009-07-231449
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发表时间：
2010-01-21
期刊：
影响因子：
20.3
通讯作者：
Vidal, Michel
中科院分区：
文献类型：
--
作者：
Barres, Celine;Blanc, Lionel;Vidal, Michel
网织红细胞在其成熟为红细胞期间释放称为外泌体的小膜囊泡。外泌体是多泡内体的管腔内囊泡，通过这些内体区室与质膜融合而释放到细胞外介质中。这种分泌途径通过消除某些膜糖蛋白而有助于网织红细胞质膜重塑。我们在这项研究中表明，半乳糖凝集素-5，虽然主要是胞浆，也存在于大鼠网织红细胞和红细胞的细胞表面。此外，在网织红细胞中，它存在于内体区室中。我们记录了半乳糖凝集素-5从胞质溶胶易位到内体腔中，导致其与外泌体相关的分泌。结合到囊泡表面的半乳糖凝集素-5可能在分选半乳糖承载糖缀合物中起作用。恰当地，我们发现Lamp 2，一种主要的细胞糖蛋白，呈现半乳糖凝集素反应性聚-N-乙酰乳糖胺链，在网织红细胞成熟过程中丢失。它与释放的外泌体相关，提示与半乳糖凝集素-5结合。最后，我们揭示了巨噬细胞对大鼠网织红细胞外泌体的摄取依赖于温度和机械酶动力蛋白，并且外泌体的摄取通过添加半乳糖凝集素-5而降低。这些数据暗示了在大鼠网织红细胞成熟期间半乳糖凝集素-5在外泌体分选途径中的功能。（血。2010; 115：696-705）
Reticulocytes release small membrane vesicles termed exosomes during their maturation into erythrocytes. Exosomes are intraluminal vesicles of multivesicular endosomes released into the extracellular medium by fusion of these endosomal compartments with the plasma membrane. This secretion pathway contributes to reticulocyte plasma membrane remodeling by eliminating certain membrane glycoproteins. We show in this study that galectin-5, although mainly cytosolic, is also present on the cell surface of rat reticulocytes and erythrocytes. In addition, in reticulocytes, it resides in the endosomal compartment. We document galectin-5 translocation from the cytosol into the endosome lumen, leading to its secretion in association with exosomes. Galectin-5 bound onto the vesicle surface may function in sorting galactose-bearing glycoconjugates. Fittingly, we found that Lamp2, a major cellular glycoprotein presenting galectin-reactive poly-N-acetylactosamine chains, is lost during reticulocyte maturation. It is associated with released exosomes, suggestive of binding to galectin-5. Finally, we reveal that the uptake of rat reticulocyte exosomes by macrophages is dependent on temperature and the mechanoenzyme dynamin and that exosome uptake is decreased by adding galectin-5. These data imply galectin-5 functionality in the exosomal sorting pathway during rat reticulocyte maturation. (Blood. 2010; 115: 696-705)