title: Differential modulation of adhesion molecule expression by hydroxycarbamide in human endothelial cells from the micro- and macrocirculation: potential implications in sickle cell disease vasoocclusive events.
abstract: BACKGROUND
  All the cellular partners of the vascular system and especially endothelial cells are involved in the pathophysiology of the vasoocclusive crises associated with sickle cell disease. In sickle cell disease, circulating cells adhere abnormally to endothelial cells in a chronic pro-inflammatory context. Hydroxycarbamide is the only drug with demonstrated efficacy to reduce the frequency of vasoocclusive crises. Here, we investigated the effects of hydroxycarbamide and/or cytokines on the expression of genes related to adhesion events in endothelial cells from three different vascular sites.
  
  
  METHODS
  Endothelial cells representative of the macro- (HUVEC) or microcirculation (TrHBMEC and HPMEC) were grown in the presence or absence of hydroxycarbamide and/or cytokines (TNFα and IFNγ). Expression of genes encoding adhesion proteins was analyzed by RQ-PCR, ELISA, flow cytometry, in situ ELISA for extracellular matrix proteins, and Western blot.
  
  
  RESULTS
  In cells from the microcirculation, expression of TSP-1, vWF, and PECAM-1 genes was decreased by hydroxycarbamide and/or cytokine treatment at the mRNA level. In the macro-circulation their expression was unaffected or increased. Hydroxycarbamide significantly decreased vWF incorporated in the TrHBMEC extracellular matrix. CD36 mRNA was strongly down-regulated by cytokines in HPMEC, the only cell type in which it is expressed. Hydroxycarbamide decreased soluble PECAM-1 in HUVEC supernatants.
  
  
  CONCLUSIONS
  Our results highlight the heterogeneity of vascular endothelial cell responses to hydroxycarbamide and/or cytokines depending upon their origin. They also suggest that hydroxycarbamide has an anti-adhesogenic effect on endothelial cells, but by mechanisms which could vary according to their macro- or microcirculation and organ origin.
authors.affiliation: INSERM, UMR_S763, Hôpital, Robert Debré, 48 boulevard, Sérurier, 75019 Paris, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Laurance
authors.forename: Pauline
authors.initials: P
authors.lastname: Lansiaux
authors.forename: François-Xavier
authors.initials: FX
authors.lastname: Pellay
authors.forename: Michelle
authors.initials: M
authors.lastname: Hauchecorne
authors.forename: Arndt
authors.initials: A
authors.lastname: Benecke
authors.forename: Jacques
authors.initials: J
authors.lastname: Elion
authors.forename: Claudine
authors.initials: C
authors.lastname: Lapoumeroulie
mesh_terms: D000755:Anemia, Sickle Cell / Q000235:genetics* / Q000378:metabolism* / Q000503:physiopathology; D000986:Antisickling Agents / Q000494:pharmacology; D015815:Cell Adhesion Molecules / Q000235:genetics* / Q000378:metabolism; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D006918:Hydroxyurea / Q000494:pharmacology*; D046228:Microarray Analysis; D019700:Thrombospondin 1 / Q000235:genetics; D014841:von Willebrand Factor / Q000235:genetics
chemical_list: D000986:Antisickling Agents; D015815:Cell Adhesion Molecules; D019700:Thrombospondin 1; D014841:von Willebrand Factor; D006918:Hydroxyurea