title: HOX decoy peptide enhances the ex vivo expansion of human umbilical cord blood CD34+ hematopoietic stem cells/hematopoietic progenitor cells.
abstract: HOX transcription factors play important roles in the self-renewal of hematopoietic cells. HOX proteins interact with the non-HOX homeobox protein PBX1 to regulate, both positively and negatively, the expression of target genes. In this study, we synthesized a decoy peptide containing the YPWM motif from HOX proteins (decoy HOX [decHOX]), which was predicted to act as a HOX mimetic, and analyzed its effects on self-renewal of human cord blood CD34(+) cells. We were able to deliver decHOX into approximately 70% of CD34(+) cells. By examining the expression of HOX target genes c-myc and p21(waf1/cip1), we confirmed that decHOX enhanced HOX functions. After 7 days of culture in serum-free medium containing a cytokine cocktail, cultures treated with decHOX had approximately twofold-increased numbers of CD34(+) cells and primitive multipotent progenitor cells compared with control cells. Furthermore, decHOX-treated cells reconstituted hematopoiesis in nonobese diabetic/severe combined immunodeficiency mice more rapidly and more effectively (more than twofold greater efficiency, as determined by a limiting dilution method) than control cells. decHOX-treated cells were also able to repopulate secondary recipients. Together, these results indicate that in combination with growth factors and/or other approaches, decHOX might be a useful new tool for the ex vivo expansion of hematopoietic stem/progenitor cells.
authors.affiliation: Department of Regenerative Medicine, Institute of Biomedical Research and Innovation, Kobe, Japan. htanaka@fbri.org
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Tanaka
authors.forename: Itaru
authors.initials: I
authors.lastname: Matsumura
authors.forename: Kiminari
authors.initials: K
authors.lastname: Itoh
authors.forename: Asako
authors.initials: A
authors.lastname: Hatsuyama
authors.forename: Masayuki
authors.initials: M
authors.lastname: Shikamura
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Satoh
authors.forename: Toshio
authors.initials: T
authors.lastname: Heike
authors.forename: Tatsutoshi
authors.initials: T
authors.lastname: Nakahata
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Kanakura
mesh_terms: D000818:Animals; D018952:Antigens, CD34 / Q000032:analysis; D001853:Bone Marrow / Q000473:pathology / Q000528:radiation effects; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D036101:Cord Blood Stem Cell Transplantation; D016207:Cytokines / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000378:metabolism; D005312:Fetal Blood / Q000166:cytology / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D018398:Homeodomain Proteins / Q000378:metabolism*; D006801:Humans; D016130:Immunophenotyping; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D018716:Molecular Mimicry; D010455:Peptides / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D000075062:Pre-B-Cell Leukemia Transcription Factor 1; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic / Q000187:drug effects; D014916:Whole-Body Irradiation
chemical_list: D018952:Antigens, CD34; D016207:Cytokines; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D010455:Peptides; D000075062:Pre-B-Cell Leukemia Transcription Factor 1; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; C083400:PBX1 protein, human