title: Influence of local environment on the differentiation of neural stem cells engrafted onto the injured spinal cord.
abstract: OBJECTIVE
  In vitro, neural stem cells (NSCs) proliferate as undifferentiated spheroids and differentiate into neurons, astrocytes and oligodendrocytes. These features make NSCs suitable for spinal cord (SC) reconstruction. However, in vivo experiments have demonstrated that in the injured SC transplanted NSCs either remain undifferentiated or differentiate into the astrocytic phenotype. The microenvironment of the injured SC is believed to play a crucial role in driving the differentiation of the engrafted NSCs. Here, we tested the hypothesis that inflammatory cytokines (ICs) may be involved in the restricted differentiation of NSCs after grafting onto the injured SC.
  
  
  METHODS
  As the first step, we used immunohistochemistry to analyse the expression of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta and interferon (IFN)-gamma in the normal SC of mice and following traumatic injury. Then, we investigated whether a combination of TNF-alpha, IL-1beta and IFN-gamma may affect the phenotype of murine NSCs in vitro.
  
  
  RESULTS
  We found that TNF-alpha, IL-1beta and IFN-gamma, which are absent in the normal SC, are all expressed in the injured SC and the expression of these cytokines follows a timely tuned fashion with IFN-gamma being detectable as long as 4 weeks after injury. In culture, exposure of proliferating NSCs to a combination of TNF-alpha, IL-1beta and IFN-gamma was per se sufficient to induce the astrocytic differentiation of these cells even in the absence of serum.
  
  
  CONCLUSIONS
  In the traumatically injured SC, differentiation of engrafted NSCs is restricted towards the astrocytic lineage because of the inflammatory environment. ICs are likely to play a major role in differentiation of NSCs in the in vivo conditions.
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Ricci-Vitiani
authors.forename: Patrizia
authors.initials: P
authors.lastname: Casalbore
authors.forename: Giovanna
authors.initials: G
authors.lastname: Petrucci
authors.forename: Liverana
authors.initials: L
authors.lastname: Lauretti
authors.forename: Nicola
authors.initials: N
authors.lastname: Montano
authors.forename: Luigi Maria
authors.initials: LM
authors.lastname: Larocca
authors.forename: Maria Laura
authors.initials: ML
authors.lastname: Falchetti
authors.forename: Dario Giuseppe
authors.initials: DG
authors.lastname: Lombardi
authors.forename: Valeria Di Giorgio
authors.initials: VD
authors.lastname: Gerevini
authors.forename: Carlo
authors.initials: C
authors.lastname: Cenciarelli
authors.forename: Quintino Giorgio
authors.initials: QG
authors.lastname: D'Alessandris
authors.forename: Eduardo
authors.initials: E
authors.lastname: Fernandez
authors.forename: Ruggero
authors.initials: R
authors.lastname: De Maria
authors.forename: Giulio
authors.initials: G
authors.lastname: Maira
authors.forename: Cesare
authors.initials: C
authors.lastname: Peschle
authors.forename: Eugenio
authors.initials: E
authors.lastname: Parati
authors.forename: Roberto
authors.initials: R
authors.lastname: Pallini
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D016207:Cytokines / Q000378:metabolism* / Q000494:pharmacology; D005260:Female; D007150:Immunohistochemistry; D007371:Interferon-gamma / Q000378:metabolism / Q000494:pharmacology; D007375:Interleukin-1 / Q000378:metabolism / Q000494:pharmacology; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000637:transplantation*; D013119:Spinal Cord Injuries / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D033581:Stem Cell Transplantation; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000494:pharmacology
chemical_list: D016207:Cytokines; D007375:Interleukin-1; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma