title: Clonal analysis of thymus-repopulating cells presents direct evidence for self-renewal division of human hematopoietic stem cells.
abstract: To elucidate the in vivo kinetics of human hematopoietic stem cells (HSCs), CD34+CD38- cells were infected with lentivirus vector and transplanted into immunodeficient mice. We analyzed the multilineage differentiation and self-renewal abilities of individual thymus-repopulating clones in primary recipients, and their descending clones in paired secondary recipients, by tracing lentivirus gene integration sites in each lymphomyeloid progeny using a linear amplification-mediated polymerase chain reaction (PCR) strategy. Our clonal analysis revealed that a single human thymus-repopulating cell had the ability to produce lymphoid and myeloid lineage cells in the primary recipient and each secondary recipient, indicating that individual human HSCs expand clonally by self-renewal division. Furthermore, we found that the proportion of HSC clones present in the CD34+ cell population decreased as HSCs replicated during extensive repopulation and also as the differentiation capacity of the HSC clones became limited. This indicates the restriction of the ability of individual HSCs despite the expansion of total HSC population. We also demonstrated that the extensive self-renewal potential was confined in the relatively small proportion of HSC clones. We conclude that our clonal tracking studies clearly demonstrated that heterogeneity in the self-renewal capacity of HSC clones underlies the differences in clonal longevity in the CD34+ stem cell pool.
authors.affiliation: Division of Hematopoiesis, Research Center for Regenerative Medicine, Tokai University School of Medicine, Isehara, Kanagawa.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yahata
authors.forename: Shizu
authors.initials: S
authors.lastname: Yumino
authors.forename: Yin
authors.initials: Y
authors.lastname: Seng
authors.forename: Hiroko
authors.initials: H
authors.lastname: Miyatake
authors.forename: Tomoko
authors.initials: T
authors.lastname: Uno
authors.forename: Yukari
authors.initials: Y
authors.lastname: Muguruma
authors.forename: Mamoru
authors.initials: M
authors.lastname: Ito
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Miyoshi
authors.forename: Shunichi
authors.initials: S
authors.lastname: Kato
authors.forename: Tomomitsu
authors.initials: T
authors.lastname: Hotta
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Ando
mesh_terms: D051997:ADP-ribosyl Cyclase 1 / Q000096:biosynthesis; D000818:Animals; D018952:Antigens, CD34 / Q000096:biosynthesis; D002454:Cell Differentiation; D019070:Cell Lineage; D006410:Hematopoiesis; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D007700:Kinetics; D016086:Lentivirus / Q000235:genetics; D051379:Mice; D016513:Mice, SCID; D008954:Models, Biological; D013950:Thymus Gland / Q000166:cytology* / Q000378:metabolism
chemical_list: D018952:Antigens, CD34; D051997:ADP-ribosyl Cyclase 1