We isolated the exosomes from mouse bone marrow fluid, mouse primary bone marrow endothelial cells (BMEC) culture supernatants of WT-BMEC and Vps33b knockdown BMECs by ultracentrifugation. After characterization of isolated exosomes, A global comparison of the protein cargo carried by the different exosomes. In brief，protein were extracted and labeled with TMT, the peptide were subjected to NSI source followed by tandem mass spectrometry (MS/MS) in a Q Exactive HF-X (Thermo) coupled with an EASY-nLC 1200 UPLC system, and the resulting MS/MS data were processed using the MaxQuant search engine.