title: [Investigation on the internalization pathway of microparticles into human umbilical cord endothelial cells].
abstract: OBJECTIVE
  To investigate the mechanisms underlying the incorporation of microparticles(MP) derived from human bone marrow mesenchymal stem cells (MSCs) into human umbilical cord endothelial cells (HUVECs).
  
  
  METHODS
  MPs were isolated from the supernatants of MSCs which had exposed to a hypoxia/serum-deprivation condition. Electron microscope was used to identify the MPs. The surface molecule profile was evaluated with the bead-based flow cytometry technique. The expression level of the phosphatidylserine receptor (PSR) was detected by immunofluorescence cytochemistry. MPs were co-cultured with HUVECs in the presence or absence PSR-antibody, and the internalization of MPs was observed with laser scanning microscopy.
  
  
  RESULTS
  The MPs derived from MSCs expressed highly PS, while PSR expressed on the surface of HUVECs. The confocal result revealed that MPs could quickly be uptaken by the endothelial cells, and mainly distributed in the cytoplasm surrounding of the nuclei. The internalization of MPs reduced significantly after PSR specific blockage.
  
  
  CONCLUSIONS
  The reaction between PS on the MP and the PSR of HUVECs plays an important role in the internalization of MSC-MPs.
authors.affiliation: The fourth Military Medical University, Xi'an 710032.
authors.forename: Xiao-Juan
authors.initials: XJ
authors.lastname: Wei
authors.affiliation: General Hospital of Chinese Air Force, Beijing 100042.
authors.forename: Hong-Chao
authors.initials: HC
authors.lastname: Zhang
authors.affiliation: Hebei Medical University, Hebei 050000.
authors.forename: Zheng-Zheng
authors.initials: ZZ
authors.lastname: Shen
authors.affiliation: Beijing Institute of Radiation Medicine, Beijing 100850.
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.affiliation: Beijing Institute of Radiation Medicine, Beijing 100850.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Beijing Institute of Radiation Medicine, Beijing 100850.
authors.forename: Zi-Kuan
authors.initials: ZK
authors.lastname: Guo
authors.affiliation: The fourth Military Medical University, Xi'an 710032. E-mail: liu_chaozhong@sohu.com.|General Hospital of Chinese Air Force, Beijing 100042. E-mail: liu_chaozhong@sohu.com.
authors.forename: Chao-Zhong
authors.initials: CZ
authors.lastname: Liu
mesh_terms: D002478:Cells, Cultured; D018920:Coculture Techniques; D042783:Endothelial Cells; D005434:Flow Cytometry; D006801:Humans; D059630:Mesenchymal Stem Cells; D014470:Umbilical Cord