title: Progenitor cell trafficking is regulated by hypoxic gradients through HIF-1 induction of SDF-1.
abstract: The trafficking of circulating stem and progenitor cells to areas of tissue damage is poorly understood. The chemokine stromal cell-derived factor-1 (SDF-1 or CXCL12) mediates homing of stem cells to bone marrow by binding to CXCR4 on circulating cells. SDF-1 and CXCR4 are expressed in complementary patterns during embryonic organogenesis and guide primordial stem cells to sites of rapid vascular expansion. However, the regulation of SDF-1 and its physiological role in peripheral tissue repair remain incompletely understood. Here we show that SDF-1 gene expression is regulated by the transcription factor hypoxia-inducible factor-1 (HIF-1) in endothelial cells, resulting in selective in vivo expression of SDF-1 in ischemic tissue in direct proportion to reduced oxygen tension. HIF-1-induced SDF-1 expression increases the adhesion, migration and homing of circulating CXCR4-positive progenitor cells to ischemic tissue. Blockade of SDF-1 in ischemic tissue or CXCR4 on circulating cells prevents progenitor cell recruitment to sites of injury. Discrete regions of hypoxia in the bone marrow compartment also show increased SDF-1 expression and progenitor cell tropism. These data show that the recruitment of CXCR4-positive progenitor cells to regenerating tissues is mediated by hypoxic gradients via HIF-1-induced expression of SDF-1.
authors.affiliation: Laboratory of Microvascular Research and Vascular Tissue Engineering, Institute of Reconstructive Plastic Surgery, New York University School of Medicine, New York, New York 10016, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Ceradini
authors.forename: Anita R
authors.initials: AR
authors.lastname: Kulkarni
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Callaghan
authors.forename: Oren M
authors.initials: OM
authors.lastname: Tepper
authors.forename: Nicholas
authors.initials: N
authors.lastname: Bastidas
authors.forename: Mark E
authors.initials: ME
authors.lastname: Kleinman
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Capla
authors.forename: Robert D
authors.initials: RD
authors.lastname: Galiano
authors.forename: Jamie P
authors.initials: JP
authors.lastname: Levine
authors.forename: Geoffrey C
authors.initials: GC
authors.lastname: Gurtner
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001853:Bone Marrow / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology; D015687:Cell Hypoxia / Q000502:physiology; D002465:Cell Movement / Q000502:physiology*; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000378:metabolism* / Q000502:physiology; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005786:Gene Expression Regulation; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D017403:In Situ Hybridization; D007511:Ischemia / Q000378:metabolism*; D051379:Mice; D008819:Mice, Nude; D009687:Nuclear Proteins / Q000378:metabolism*; D011233:Precipitin Tests; D019718:Receptors, CXCR4 / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000502:physiology*; D014157:Transcription Factors
chemical_list: D054377:Chemokine CXCL12; D019743:Chemokines, CXC; C515256:Cxcl12 protein, mouse; D004268:DNA-Binding Proteins; C497443:Hif1a protein, mouse; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009687:Nuclear Proteins; D019718:Receptors, CXCR4; D014157:Transcription Factors