title: Extramedullary hematopoiesis is dysregulated in histamine-free histidine decarboxylase knockout (HDC-/-) mice.
abstract: OBJECTIVE
  In this study we investigated the role of histamine on the extramedullary hematopoiesis.
  
  
  METHODS
  Male histidine decarboxylase knockout (HDC(-/-)) mice and wild-type mice were used (n = 5/group). Groups of mice received sublethal total-body gamma irradiation at a single dose of 4 Gy. Spleen cells were studied at different time points post-irradiation by flow cytometry, colony forming unit (CFU) assay, and real-time PCR. For statistical analysis Student's t test, ANOVA, and Holm-Sidak post-hoc test were used.
  
  
  RESULTS
  By day 14 after irradiation, spleen cell counts increased almost eightfold in wild-type and not even fourfold in HDC(-/-) mice (P < 0.01). The proliferative capacity and interleukin-3 signaling of stem cells were impaired in HDC(-/-) mice. STAT5 mRNA expression was decreased in granulocyte-myeloid colonies by 72.9 +/- 8.6% (P < 0.001), compared to the wild-type.
  
  
  CONCLUSIONS
  The absence of histamine adversely affects splenic hematopoiesis via direct and indirect mechanisms.
authors.affiliation: Department of Genetics, Semmelweis University, Nagyvárad tér 4, 1089 Budapest, Hungary.
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Horváth
authors.forename: Eva
authors.initials: E
authors.lastname: Pállinger
authors.forename: Gyozo
authors.initials: G
authors.lastname: Horváth
authors.forename: Ivett
authors.initials: I
authors.lastname: Jelinek
authors.forename: Gizella
authors.initials: G
authors.lastname: Veszely
authors.forename: József
authors.initials: J
authors.lastname: Furész
authors.forename: András
authors.initials: A
authors.lastname: Falus
authors.forename: Edit I
authors.initials: EI
authors.lastname: Buzás
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D005434:Flow Cytometry; D006411:Hematopoiesis, Extramedullary / Q000235:genetics* / Q000502:physiology*; D006632:Histamine / Q000502:physiology*; D006640:Histidine Decarboxylase / Q000235:genetics* / Q000502:physiology*; D007377:Interleukin-3 / Q000494:pharmacology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D012038:Regeneration; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050799:STAT5 Transcription Factor / Q000096:biosynthesis / Q000235:genetics; D013154:Spleen / Q000166:cytology / Q000187:drug effects; D013234:Stem Cells / Q000187:drug effects; D014916:Whole-Body Irradiation
chemical_list: D007377:Interleukin-3; D012333:RNA, Messenger; D050799:STAT5 Transcription Factor; D006632:Histamine; D006640:Histidine Decarboxylase