title: Pten regulates homeostasis and inflammation-induced migration of myelocytes in zebrafish.
abstract: BACKGROUND
  Loss of the tumor suppressor phosphatase and tensin homolog (PTEN) is frequently observed in hematopoietic malignancies. Although PTEN has been implicated in maintaining the quiescence of hematopoietic stem cells (HSCs), its role in hematopoiesis during ontogeny remains largely unexplored.
  
  
  METHODS
  The expression of hematopoietic marker genes was analyzed via whole mount in situ hybridization assay in ptena and ptenb double mutant zebrafish. The embryonic myelopoiesis was characterized by living imaging and whole mount in situ immunofluorescence with confocal microscopy, as well as cell-specific chemical staining for neutrophils and macrophages. Analyses of the involved signaling pathway were carried out by inhibitor treatment and mRNA injection.
  
  
  RESULTS
  Pten-deficient zebrafish embryos exhibited a strikingly increased number of myeloid cells, which were further characterized as being immune deficient. In accordance with this finding, the inhibition of phosphoinositide 3-kinase (PI3K) or the mechanistic target of rapamycin (mTOR) corrected the expansive myelopoiesis in the pten-deficient embryos. Further mechanistic studies revealed that the expression of cebpa, a critical transcription factor in myeloid precursor cells, was downregulated in the pten-deficient myeloid cells, whereas the injection of cebpa mRNA markedly ameliorated the dysmyelopoiesis induced by the loss of pten.
  
  
  CONCLUSIONS
  Our data provide in vivo evidence that definitive myelopoiesis in zebrafish is critically regulated by pten via the elevation of cebpa expression.
authors.forename: Zhi-Wei
authors.initials: ZW
authors.lastname: Dong
authors.forename: Chun-Guang
authors.initials: CG
authors.lastname: Ren
authors.forename: Yu
authors.initials: Y
authors.lastname: Xia
authors.forename: Dan
authors.initials: D
authors.lastname: Su
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Du
authors.forename: Hong-Bo
authors.initials: HB
authors.lastname: Fan
authors.forename: Hao
authors.initials: H
authors.lastname: Yuan
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Mei
authors.initials: M
authors.lastname: Dong
authors.forename: Wei-Chun
authors.initials: WC
authors.lastname: Li
authors.forename: Yi
authors.initials: Y
authors.lastname: Jin
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.forename: Min
authors.initials: M
authors.lastname: Deng
authors.forename: Ting-Xi
authors.initials: TX
authors.lastname: Liu
authors.affiliation: Key Laboratory of Stem Cell Biology, State Key Laboratory for Medical Genomics and Laboratory of Development and Diseases, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai 200025, China. aihuagu@njmu.edu.cn.
authors.forename: Ai-Hua
authors.initials: AH
authors.lastname: Gu
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D048708:Cell Growth Processes / Q000502:physiology; D002465:Cell Movement / Q000502:physiology*; D006706:Homeostasis; D007249:Inflammation / Q000378:metabolism*; D022423:Myeloid Cells / Q000166:cytology* / Q000378:metabolism*; D051059:PTEN Phosphohydrolase / Q000378:metabolism*; D015027:Zebrafish
chemical_list: D051059:PTEN Phosphohydrolase