title: Differential role of gp130-dependent STAT and Ras signalling for haematopoiesis following bone-marrow transplantation.
abstract: BACKGROUND
  Bone marrow transplantation (BMT) is a complex process regulated by different cytokines and growth factors. The pleiotropic cytokine IL-6 (Interleukin-6) and related cytokines of the same family acting on the common signal transducer gp130 are known to play a key role in bone marrow (BM) engraftment. In contrast, the exact signalling events that control IL-6/gp130-driven haematopoietic stem cell development during BMT remain unresolved.
  
  
  METHODS
  Conditional gp130 knockout and knockin mice were used to delete gp130 expression (gp130(ΔMx)), or to selectively disrupt gp130-dependent Ras (gp130(ΔMxRas)) or STAT signalling (gp130(ΔMxSTAT)) in BM cells. BM derived from the respective strains was transplanted into irradiated wildtype hosts and repopulation of various haematopoietic lineages was monitored by flow cytometry.
  
  
  RESULTS
  BM derived from gp130 deficient donor mice (gp130(ΔMx)) displayed a delayed engraftment, as evidenced by reduced total white blood cells (WBC), marked thrombocytopenia and anaemia in the early phase after BMT. Lineage analysis unravelled a restricted development of CD4(+) and CD8(+) T-cells, CD19(+) B-cells and CD11b(+) myeloid cells after transplantation of gp130-deficient BM grafts. To further delineate the two major gp130-induced signalling cascades, Ras-MAPK and STAT1/3-signalling respectively, we used gp130(ΔMxRas) and gp130(ΔMxSTAT) donor BM. BMT of gp130(ΔMxSTAT) cells significantly impaired engraftment of CD4(+), CD8(+), CD19(+) and CD11b(+) cells, whereas gp130(ΔMxRas) BM displayed a selective impairment in early thrombopoiesis. Importantly, gp130-STAT1/3 signalling deficiency in BM grafts severely impaired survival of transplanted mice, thus demonstrating a pivotal role for this pathway in BM graft survival and function.
  
  
  CONCLUSIONS
  Our data unravel a vital function of IL-6/gp130-STAT1/3 signals for BM engraftment and haematopoiesis, as well as for host survival after transplantation. STAT1/3 and ras-dependent pathways thereby exert distinct functions on individual bone-marrow-lineages.
authors: Department of Medicine III, University Hospital Aachen, Aachen, Germany.
authors: Daniela C
authors: DC
authors: Kroy
authors: Lisa
authors: L
authors: Hebing
authors: Leif E
authors: LE
authors: Sander
authors: Nikolaus
authors: N
authors: Gassler
authors: Stephanie
authors: S
authors: Erschfeld
authors: Sara
authors: S
authors: Sackett
authors: Oliver
authors: O
authors: Galm
authors: Christian
authors: C
authors: Trautwein
authors: Konrad L
authors: KL
authors: Streetz
mesh_terms: D000818:Animals; D016026:Bone Marrow Transplantation; D050822:Cytokine Receptor gp130 / Q000235:genetics / Q000378:metabolism*; D006410:Hematopoiesis / Q000235:genetics / Q000502:physiology*; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D008817:Mice, Mutant Strains; D050791:STAT Transcription Factors / Q000235:genetics / Q000378:metabolism*; D050794:STAT1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D050791:STAT Transcription Factors; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor; D050822:Cytokine Receptor gp130; D018631:ras Proteins