title: Recombinant TAT-BMI-1 fusion protein induces ex vivo expansion of human umbilical cord blood-derived hematopoietic stem cells.
abstract: Transplantation of hematopoietic stem cells (HSCs) is a well-established therapeutic approach for numerous disorders. HSCs are typically derived from bone marrow or peripheral blood after cytokine-induced mobilization. Umbilical cord blood (CB) represents an appealing alternative HSC source, but the small amounts of the individual CB units have limited its applications. The availability of strategies for safe ex vivo expansion of CB-derived HSCs (CB-HSCs) may allow to extend the use of these cells in adult patients and to avoid the risk of insufficient engraftment or delayed hematopoietic recovery.Here we describe a system for the ex vivo expansion of CB-HSCs based on their transient exposure to a recombinant TAT-BMI-1 chimeric protein. BMI-1 belongs to the Polycomb family of epigenetic modifiers and is recognized as a central regulator of HSC self-renewal. Recombinant TAT-BMI-1 produced in bacteria was able to enter the target cells via the HIV TAT-derived protein transduction peptide covalently attached to BMI-1, and conserved its biological activity. Treatment of CB-CD34+ cells for 3 days with repeated addition of 10 nM purified TAT-BMI-1 significantly enhanced total cell expansion as well as that of primitive hematopoietic progenitors in culture. Importantly, TAT-BMI-1-treated CB-CD34+ cells displayed a consistently higher rate of multi-lineage long-term repopulating activity in primary and secondary xenotransplants in immunocompromised mice. Thus, recombinant TAT-BMI-1 may represent a novel, effective reagent for ex vivo expansion of CB-HSC for therapeutic purposes.
authors.affiliation: Laboratory of Molecular Haematopoiesis and Stem Cell Biology, University Magna Græcia, Catanzaro, Italy.
authors.forename: Bruna
authors.initials: B
authors.lastname: Codispoti
authors.affiliation: Biogem S.C.a R.L., Ariano Irpino, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Rinaldo
authors.affiliation: Laboratory of Molecular Haematopoiesis and Stem Cell Biology, University Magna Græcia, Catanzaro, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Chiarella
authors.affiliation: Molecular Medicine Program, European Institute of Oncology, Milano, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Lupia
authors.affiliation: Laboratory of Molecular Haematopoiesis and Stem Cell Biology, University Magna Græcia, Catanzaro, Italy.
authors.forename: Cristina Barbara
authors.initials: CB
authors.lastname: Spoleti
authors.affiliation: Laboratory of Molecular Haematopoiesis and Stem Cell Biology, University Magna Græcia, Catanzaro, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Marafioti
authors.affiliation: Laboratory of Molecular Haematopoiesis and Stem Cell Biology, University Magna Græcia, Catanzaro, Italy.
authors.forename: Annamaria
authors.initials: A
authors.lastname: Aloisio
authors.affiliation: Laboratory of Molecular Haematopoiesis and Stem Cell Biology, University Magna Græcia, Catanzaro, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Scicchitano
authors.affiliation: Molecular Medicine Program, European Institute of Oncology, Milano, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Giordano
authors.affiliation: Laboratory of Molecular Haematopoiesis and Stem Cell Biology, University Magna Græcia, Catanzaro, Italy.|YCR Cancer Research Unit-Department of Biology, University of York, York, United Kingdom.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Nappo
authors.affiliation: Laboratory of Molecular Haematopoiesis and Stem Cell Biology, University Magna Græcia, Catanzaro, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Lucchino
authors.affiliation: Department of Cell Biology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: Malcolm A S
authors.initials: MAS
authors.lastname: Moore
authors.affiliation: Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY, USA.
authors.forename: Pengbo
authors.initials: P
authors.lastname: Zhou
authors.affiliation: Laboratory of Molecular Haematopoiesis and Stem Cell Biology, University Magna Græcia, Catanzaro, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Mesuraca
authors.affiliation: Laboratory of Molecular Haematopoiesis and Stem Cell Biology, University Magna Græcia, Catanzaro, Italy.
authors.forename: Heather Mandy
authors.initials: HM
authors.lastname: Bond
authors.affiliation: Laboratory of Molecular Haematopoiesis and Stem Cell Biology, University Magna Græcia, Catanzaro, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Morrone
mesh_terms: D000818:Animals; D015415:Biomarkers; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D005260:Female; D005312:Fetal Blood / Q000166:cytology*; D006085:Graft Survival; D006410:Hematopoiesis; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D051379:Mice; D063150:Polycomb Repressive Complex 1; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D054322:tat Gene Products, Human Immunodeficiency Virus
chemical_list: D015415:Biomarkers; D011993:Recombinant Fusion Proteins; D054322:tat Gene Products, Human Immunodeficiency Virus; D063150:Polycomb Repressive Complex 1
keywords: BMI-1; TAT-fusion protein; ex vivo expansion; hematopoietic stem cells (HSCs); protein transduction