title: [Influence of TLR2- and TLR4-activated Mesenchymal Stem Cells on Migration of Cord Blood CD34+ Cells].
abstract: OBJECTIVE
  This study was aimed to investigate the possible effect of Toll-like receptors 2 (TLR2) and Toll-like receptors 4 (TLR4) on the migration function of umbilical cord blood (UCB) CD34+ hematopoietic stem/progenitor cells induced by bone marrow-derived mesenchymal stem cells (MSCs) and to explore the underlying mechanism.
  
  
  METHODS
  The expression of TLR2 and TLR4 on MSC was detected with flow cytometry. After the MSC were pretreated with TLR2 agonist (PAM3CSK4) and/or TLR4 agonist (LPS), the supernatants were collected. The effect of the supernatants on the migration of CD34+ cells was evaluated with chemotaxis assays. Alterations of chemokine (SDF-1) secreted by MSC in the supernatants were assayed by ELISA.
  
  
  RESULTS
  The expression levels of TLR2 and TLR4 were (31.5±4.6)% and (85.6±6.7)% respectively. Compared with the blank group, the migration ability of CD34+ cells increased significantly in control, LPS and/or PAM3CSK4 groups (P<0.01). Further study found that LPS and/or PAM3CSK4 enhanced the chemotactic ability of CD34+ cells (P<0.05), but the concentration of SDF-1 was not changed significantly in all of LPS and/or PAM3CSK4 groups (P>0.05) in comparison with the control group.
  
  
  CONCLUSIONS
  TLR2 and TLR4 signalings may indirectly increase the migration of CD34+ hematopoietic stem/progenitor cells by modulating BM-MSC functions, which may not significantly correlate with the production of chemokine SDF-1 by MSCs.
authors.affiliation: Department of Hematology of Anhui Provincial Hospital, Anhui Medical University, Hefei 230001, Anhui Province, China.
authors.forename: Yun-Xia
authors.initials: YX
authors.lastname: Zhu
authors.affiliation: Department of Hematology of Anhui Provincial Hospital, Anhui Medical University, Hefei 230001, Anhui Province, China. E-mail: wangxingbing91@hotmail.com.
authors.forename: Xing-Bing
authors.initials: XB
authors.lastname: Wang
authors.affiliation: Department of Hematology of Anhui Provincial Hospital, Anhui Medical University, Hefei 230001, Anhui Province, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Hematology of Anhui Provincial Hospital, Anhui Medical University, Hefei 230001, Anhui Province, China.
authors.forename: Zong-Hai
authors.initials: ZH
authors.lastname: Yan
mesh_terms: D018952:Antigens, CD34; D002465:Cell Movement; D002478:Cells, Cultured; D054377:Chemokine CXCL12; D005312:Fetal Blood; D006412:Hematopoietic Stem Cells; D006801:Humans; D059630:Mesenchymal Stem Cells; D015398:Signal Transduction; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4
chemical_list: D018952:Antigens, CD34; C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4