title: Hypoxic preconditioning enhances the benefit of cardiac progenitor cell therapy for treatment of myocardial infarction by inducing CXCR4 expression.
abstract: Myocardial infarction rapidly depletes the endogenous cardiac progenitor cell pool, and the inefficient recruitment of exogenously administered progenitor cells limits the effectiveness of cardiac cell therapy. Recent reports indicate that interactions between the CXC chemokine stromal cell-derived factor 1 and its receptor CXC chemokine receptor 4 (CXCR4) critically mediate the ischemia-induced recruitment of bone marrow-derived circulating stem/progenitor cells, but the expression of CXCR4 in cardiac progenitor cells is very low. Here, we studied the influence of hypoxia on CXCR4 expression in cardiac progenitor cells, on the recruitment of intravenously administered cells to ischemic heart tissue, and on the preservation of heart function in a murine myocardial infarction model. We found that hypoxic preconditioning increased CXCR4 expression in CLK (cardiosphere-derived, Lin(-)c-kit(+) progenitor) cells and markedly augmented CLK cell migration (in vitro) and recruitment (in vivo) to the ischemic myocardium. Four weeks after surgically induced myocardial infarction, infarct size and heart function were significantly better in mice administered hypoxia-preconditioned CLK cells than in mice treated with cells cultured under normoxic conditions. Furthermore, these effects were largely abolished by the addition of a CXCR4 inhibitor, indicating that the benefits of hypoxic preconditioning are mediated by the stromal cell-derived factor 1/CXCR4 axis, and that therapies targeting this axis may enhance cardiac-progenitor cell-based regenerative therapy.
authors.affiliation: Stem Cell Biology, Keck Graduate Institute, Claremont, CA, USA.
authors.forename: Yao Liang
authors.initials: YL
authors.lastname: Tang
authors.forename: Wuqiang
authors.initials: W
authors.lastname: Zhu
authors.forename: Min
authors.initials: M
authors.lastname: Cheng
authors.forename: Lijuan
authors.initials: L
authors.lastname: Chen
authors.forename: John
authors.initials: J
authors.lastname: Zhang
authors.forename: Tao
authors.initials: T
authors.lastname: Sun
authors.forename: Raj
authors.initials: R
authors.lastname: Kishore
authors.forename: M Ian
authors.initials: MI
authors.lastname: Phillips
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Losordo
authors.forename: Gangjian
authors.initials: G
authors.lastname: Qin
mesh_terms: D000818:Animals; D002465:Cell Movement / Q000502:physiology; D064987:Cell- and Tissue-Based Therapy / Q000379:methods*; D002478:Cells, Cultured; D054377:Chemokine CXCL12 / Q000378:metabolism; D004195:Disease Models, Animal; D000860:Hypoxia / Q000378:metabolism*; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation / Q000379:methods*; D059630:Mesenchymal Stem Cells / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009203:Myocardial Infarction / Q000378:metabolism* / Q000473:pathology / Q000628:therapy*; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D010641:Phenotype; D019718:Receptors, CXCR4 / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology
chemical_list: C514936:CXCR4 protein, mouse; D054377:Chemokine CXCL12; C515256:Cxcl12 protein, mouse; D019718:Receptors, CXCR4