title: A novel function of interleukin-10 promoting self-renewal of hematopoietic stem cells.
abstract: Self-renewal of hematopoietic stem cells (HSCs) is key to their reconstituting ability, but the factors regulating the process remain poorly understood. Here, we show that Interleukin-10 (IL-10), a pleiotropic immune modulating cytokine, can also play a role in regulating HSC self-renewal. First, a quantitative decrease of primitive hematopoietic cell populations, but not more matured cells, was observed in the bone marrows of IL-10 disrupted mice as determined by long-term in vitro cultures or in vivo competitive repopulation assays. In contrast, normal HSCs from 5-fluorouracil treated marrows cultured on the IL-10 secreting stroma displayed an enhanced repopulating activity compared with cells grown on control stroma, with ninefold higher numbers of donor-derived HSCs in the reconstituted recipient marrows. Moreover, limiting dilution transplantation assay demonstrated that exogenous addition of IL-10 in the stroma-free cultures of purified Lin- Sca-1+ c-kit+ cells caused three- to fourfold higher frequencies of HSCs in the 5-day short-term culture without indirect inhibitory effect of IL-10 on tumor necrosis factor-alpha or interferon-gamma secretion. Interestingly, primitive hematopoietic cells, including Lin- Sca-1+ c-kit+ or side population cells, expressed the surface receptor for IL-10, and microenvironmental production of IL-10 was sharply increased in the osteoblasts lining the trabecular regions of the radiation-stressed marrow but not in the steady-state marrows. These results show that IL-10 may be a ligand that can stimulate self-renewal of HSCs to promote their regeneration in addition to being a ligand for immune regulation. Disclosure of potential conflicts of interest is found at the end of this article.
authors.affiliation: Catholic High-Performance Cell Therapy Center, The Catholic University of Korea, 505, Banpo-Dong, Seocho-Ku, Seoul, Korea 137-701.
authors.forename: Young-Ju
authors.initials: YJ
authors.lastname: Kang
authors.forename: Seung-Jip
authors.initials: SJ
authors.lastname: Yang
authors.forename: Gyeongsin
authors.initials: G
authors.lastname: Park
authors.forename: Bin
authors.initials: B
authors.lastname: Cho
authors.forename: Chang-Ki
authors.initials: CK
authors.lastname: Min
authors.forename: Tae-Yoon
authors.initials: TY
authors.lastname: Kim
authors.forename: Joon-Sung
authors.initials: JS
authors.lastname: Lee
authors.forename: Il-Hoan
authors.initials: IH
authors.lastname: Oh
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects; D002455:Cell Division; D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000187:drug effects; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D016753:Interleukin-10 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D008024:Ligands; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017154:Stromal Cells / Q000166:cytology / Q000187:drug effects
chemical_list: D008024:Ligands; D012333:RNA, Messenger; D016753:Interleukin-10