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

BackgroundAll 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. Design and MethodsEndothelial 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. ResultsIn 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 macrocirculation 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. ConclusionsOur 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.Key words: sickle cell disease, adhesion, hydroxycarbamide, vascular endothelial cells. disease vasoocclusive events. Haematologica 2011;96(4):534-542. doi:10.3324/haematol.2010 This is an open-access paper. Citation: Laurance S, Lansiaux P, Pellay F-X, Hauchecorne M, Benecke A, Elion J, and Lapoumeroulie C. Differential modulation of adhesion molecule expression by hydroxycarbamide in human endothelial cells from the micro-and macrocirculation: potential implications in sickle cell

Hydroxyurea responsiveness in -thalassemic patients is determined by the stress response adaptation of erythroid progenitors and their differentiation propensity

“…23 The expression profile of these cells is, therefore, not informative for the HbF response to HU in erythroid progenitor cells. Other studies on the effect of HU in SCD patients show decreased expression of adhesion molecules in vascular endothelial and red cells, [24][25] its stimulating effect on proinflammatory gene expression, 26 and several other pathways. [27][28] To our knowledge, none of these studies address the differential HU response in β-thalassemia.…”

Fetal hemoglobin and hydroxycarbamide moduate both plasma concentration and cellular origin of circulating microparticles in sickle cell anemia children

“…This could be supported by the observation that, in vitro, HC decreases the expression of VCAM-1, a paradigmal marker of endothelial cell activation, at the surface of endothelial cells in culture. 25 Alternatively, the decrease in MPs shed by endothelial cells in our treated children may reflect a lower injury of these cells indirectly mediated by HC through its overall inhibiting effect on RBC alterations and vaso-occlusion. Clearly further studies are warranted to clarify the HC-induced effect on both platelets and endothelial cells.…”

“…19,20 HC also reduces the number of white cells, platelets and reticulocytes, each of them contributing to the SCA-associated vaso-occlusion and vascular injury. [21][22][23] Finally, it has been shown that HC-treatment modulates the expression of erythroid and endothelial adhesion receptors and decreases the abnormal activation status of polymorphonuclear neutrophils [24][25][26] in SCA children. Such observations have led to the hypothesis that HC could have additional cellular targets other than red blood cells.…”

Hydroxycarbamide Decreases Sickle Reticulocyte Adhesion to Resting Endothelium by Inhibiting Endothelial Lutheran/Basal Cell Adhesion Molecule (Lu/BCAM) through Phosphodiesterase 4A Activation

“…Cokic et al (19) showed that in vitro short exposure of endothelial cells to HC increases cAMP and cGMP (cyclic guanosine monophosphate) and induces nitric oxide (NO) production in a NO synthase-dependent manner. We showed that in vitro treatment of endothelial cells with HC leads to a decreased expression of vascular cell adhesion molecule-1 (VCAM-1) (20) and of the vasoconstrictor peptide endothelin-1, which is in accordance with the decreased levels of plasma endothelin-1 in HC-treated children (21,22).…”