title: Thrombopoietin contributes to the formation and the maintenance of hematopoietic progenitor-containing cell clusters in the aorta-gonad-mesonephros region.
abstract: In the midgestation mouse embryo, hematopoietic cell clusters containing hematopoietic stem/progenitor cells arise in the aorta-gonad-mesonephros (AGM) region. We have previously reported that forced expression of the Sox17 transcription factor in CD45lowc-KithighAGM cells, which are the hematopoietic cellular component of the cell clusters, and subsequent coculture with OP9 stromal cells in the presence of three cytokines, stem cell factor (SCF), interleukin-3 (IL-3), and thrombopoietin (TPO), led to the formation and the maintenance of cell clusters with cells at an undifferentiated state in vitro. In this study, we investigated the role of each cytokine in the formation of hematopoietic cell clusters. We cultured Sox17-transduced AGM cells with each of the 7 possible combinations of the three cytokines. The size and the number of Sox17-transduced cell clusters in the presence of TPO, either alone or in combination, were comparable to that observed with the complete set of the three cytokines. Expression of TPO receptor, c-Mpl was almost ubiquitously expressed and maintained in Sox17-transduced hematopoietic cell clusters. In addition, the expression level of c-Mpl was highest in the CD45lowc-Kithighcells among the Sox17-transduced cell clusters. Moreover, c-Mpl protein was highly expressed in the intra-aortic hematopoietic cell clusters in comparison with endothelial cells of dorsal aorta. Finally, stimulation of the endothelial cells prepared from the AGM region by TPO induced the production of hematopoietic cells. These results suggest that TPO contributes to the formation and the maintenance of hematopoietic cell clusters in the AGM region.
authors.affiliation: Department of Stem Cell Regulation, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan.
authors.forename: Kaho
authors.initials: K
authors.lastname: Harada
authors.affiliation: Department of Stem Cell Regulation, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan. Electronic address: nobuhisa.scr@mri.tmd.ac.jp.
authors.forename: Ikuo
authors.initials: I
authors.lastname: Nobuhisa
authors.affiliation: Department of Stem Cell Regulation, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan; Department of Clinical Pathology, Suez Canal University, 4.5 Km the Ring Road, Ismailia 41522, Egypt.
authors.forename: Maha
authors.initials: M
authors.lastname: Anani
authors.affiliation: Department of Stem Cell Regulation, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan.
authors.forename: Kiyoka
authors.initials: K
authors.lastname: Saito
authors.affiliation: Department of Stem Cell Regulation, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan. Electronic address: taga.acr@mri.tmd.ac.jp.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Taga
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology* / Q000196:embryology / Q000378:metabolism; D002478:Cells, Cultured; D006066:Gonads / Q000166:cytology* / Q000196:embryology / Q000378:metabolism; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D007377:Interleukin-3 / Q000502:physiology; D008650:Mesonephros / Q000166:cytology* / Q000378:metabolism; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D053628:Receptors, Thrombopoietin / Q000378:metabolism; D055760:SOXF Transcription Factors / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D019089:Stem Cell Factor / Q000502:physiology; D013926:Thrombopoietin / Q000502:physiology*; D014161:Transduction, Genetic
chemical_list: D007377:Interleukin-3; C481270:Mpl protein, mouse; D053628:Receptors, Thrombopoietin; D055760:SOXF Transcription Factors; D019089:Stem Cell Factor; D013926:Thrombopoietin
keywords: Aorta gonad mesonephros region; Hematopoiesis; Intra-aortic hematopoietic cluster; Sox17; Thrombopoietin