title: Role of sphingosine 1-phosphate in trafficking and mobilization of hematopoietic stem cells.
abstract: OBJECTIVE
  The 'mobilization' of hematopoietic stem cells (HSCs) out of the bone marrow and into the peripheral blood is used clinically to obtain HSCs for transplantation. Although generally successful, mobilization protocols remain imperfect and the mechanisms involved are not fully understood. This review discusses the latest findings in respect to the mechanisms involved in the egress of HSCs from the bone marrow into the circulation and the potential for these recent developments to improve mobilization procedures.
  
  
  RESULTS
  It has recently become apparent that the bioactive lipid sphingosine 1-phosphate (S1P) plays an active role in attracting HSCs into the peripheral blood. S1P is the first factor identified that provides a chemoattractant gradient promoting the movement of HSCs into the peripheral blood. Drugs that mimic S1P are available with others in development, raising the possibility of increasing the strength of the egress signal and thereby improving the efficacy of mobilization procedures.
  
  
  CONCLUSIONS
  S1P is the first egress factor described for HSCs, but the details of the underlying biology are only just emerging. Although manipulating the S1P axis to enhance mobilization protocols is an exciting possibility, much needs to be learned before improvements in mobilization strategies can be realized.
authors.affiliation: Westmead Institute for Cancer Research, Westmead Millennium Institute, The University of Sydney, Sydney, Australia. linda.bendall@sydney.edu.au
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Bendall
authors.forename: Jordan
authors.initials: J
authors.lastname: Basnett
mesh_terms: D001854:Bone Marrow Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D002630:Chemotactic Factors / Q000494:pharmacology / Q000502:physiology*; D006410:Hematopoiesis / Q000187:drug effects; D019650:Hematopoietic Stem Cell Mobilization / Q000379:methods*; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006801:Humans; D008246:Lysophospholipids / Q000494:pharmacology / Q000502:physiology*; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000502:physiology
chemical_list: D002630:Chemotactic Factors; D008246:Lysophospholipids; C060506:sphingosine 1-phosphate; D013110:Sphingosine