title: Overexpression of CXCR4 on human CD34+ progenitors increases their proliferation, migration, and NOD/SCID repopulation.
abstract: A major limitation to clinical stem cell-mediated gene therapy protocols is the low levels of engraftment by transduced progenitors. We report that CXCR4 overexpression on human CD34+ progenitors using a lentiviral gene transfer technique helped navigate these cells to the murine bone marrow and spleen in response to stromal-derived factor 1 (SDF-1) signaling. Cells overexpressing CXCR4 exhibited significant increases in SDF-1-mediated chemotaxis and actin polymerization compared with control cells. A major advantage of CXCR4 overexpression was demonstrated by the ability of transduced CD34+ cells to respond to lower, physiologic levels of SDF-1 when compared to control cells, leading to improved SDF-1-induced migration and proliferation/survival, and finally resulting in significantly higher levels of in vivo repopulation of nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice including primitive CD34+/CD38(-/low) cells. Importantly, no cellular transformation was observed following transduction with the CXCR4 vector. Unexpectedly, we documented lack of receptor internalization in response to high levels of SDF-1, which can also contribute to increased migration and proliferation by the transduced CD34+ cells. Our results suggest CXCR4 overexpression for improved definitive human stem cell motility, retention, and multilineage repopulation, which could be beneficial for in vivo navigation and expansion of hematopoietic progenitors.
authors.affiliation: Department of Immunology, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Joy
authors.initials: J
authors.lastname: Kahn
authors.forename: Tamara
authors.initials: T
authors.lastname: Byk
authors.forename: Lottie
authors.initials: L
authors.lastname: Jansson-Sjostrand
authors.forename: Isabelle
authors.initials: I
authors.lastname: Petit
authors.forename: Shoham
authors.initials: S
authors.lastname: Shivtiel
authors.forename: Arnon
authors.initials: A
authors.lastname: Nagler
authors.forename: Izhar
authors.initials: I
authors.lastname: Hardan
authors.forename: Varda
authors.initials: V
authors.lastname: Deutsch
authors.forename: Zulma
authors.initials: Z
authors.lastname: Gazit
authors.forename: Dan
authors.initials: D
authors.lastname: Gazit
authors.forename: Stefan
authors.initials: S
authors.lastname: Karlsson
authors.forename: Tsvee
authors.initials: T
authors.lastname: Lapidot
mesh_terms: D000818:Animals; D018952:Antigens, CD34 / Q000378:metabolism; D002454:Cell Differentiation; D002455:Cell Division; D002465:Cell Movement; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000494:pharmacology; D015870:Gene Expression; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006085:Graft Survival; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology*; D006801:Humans; D016086:Lentivirus / Q000235:genetics; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D019718:Receptors, CXCR4 / Q000235:genetics*; D033581:Stem Cell Transplantation; D014183:Transplantation, Heterologous
chemical_list: D018952:Antigens, CD34; C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; D019743:Chemokines, CXC; C515256:Cxcl12 protein, mouse; D019718:Receptors, CXCR4