Inhibition of phosphodiesterase 9A reduces cytokine-stimulated in vitro adhesion of neutrophils from sickle cell anemia individuals
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Leukocyte adhesion to vessel walls may initiate vaso-occlusion in sickle cell anemia (SCA); however, the extent to which inflammation participates in this mechanism is not understood. This in vitro study investigated whether inflammatory molecules, commonly augmented in SCA, can affect neutrophil adhesive properties and whether cyclic guanosine monophosphate (cGMP)-elevating agents can inhibit such adhesion.
Subjects and methods
Effects of Interleukin 8 (IL-8), tumor necrosis factor-α (TNF-α), granulocyte macrophage-colony stimulating factor (GM-CSF) cytokines, BAY 73-6691 [phosphodiesterase (PDE)-9A-inhibitor], and BAY 41-2271 (guanylate-cylase stimulator) on the adhesive properties of neutrophils from healthy control (CON) and steady-state SCA individuals were determined using static-adhesion assays.
SCA neutrophils demonstrated increased adhesive properties, compared to CON neutrophils; IL-8, TNF-α and GM-CSF increased CON neutrophil adhesion and further increased SCA neutrophil adhesion to fibronectin (FN). The PDE9A inhibitor, BAY-73-6691, significantly reduced basal CON neutrophil and SCA neutrophil adhesion; this was accompanied by decreased SCA neutrophil surface expressions of the L-selectin and CD11b adhesion molecules. BAY-73-6691 also significantly reduced cytokine-stimulated CON neutrophil and SCA neutrophil adhesion to FN; however, this was not accompanied by alterations in adhesion-molecule presentation.
The chronic inflammatory nature of SCA may contribute to leukocyte adhesive functions in SCA. Furthermore, elevation of leukocyte cGMP may be an interesting approach for inhibition of leukocyte adhesion to the vessel wall, even in the presence of inflammatory stimuli.
KeywordscGMP Cytokine Inflammation Leukocyte Sickle cell anemia Vaso-occlusion
The authors thank Fernanda Perreira Cunha for assistance with flow cytometry procedures. This study was funded by FAPESP (Fundação de Amparo a Pesquisa do Estado de São Paulo) and CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico), Brazil. The Hematology and Hemotherapy Center, UNICAMP, forms part of the National Institute of Blood, Brazil (INCT de Sangue, CNPq/MCT/FAPESP).
- 7.Turhan A, Jenab P, Bruhns P, Ravetch JV, Coller BS, Frenette PS. Intravenous immune globulin prevents venular vaso-occlusion in sickle cell mice by inhibiting leukocyte adhesion and the interactions between sickle erythrocytes and adherent leukocytes. Blood. 2004;103:2397–400.PubMedCrossRefGoogle Scholar
- 11.Fadlon E, Vordermeier S, Pearson TC, Mire-Sluis AR, Dumonde DC, Phillips J, et al. Blood polymorphonuclear leukocytes from the majority of sickle cell patients in the crisis phase of the disease show enhanced adhesion to vascular endothelium and increased expression of CD64. Blood. 1998;91:266–74.PubMedGoogle Scholar
- 34.Canalli AA, Proenca-Ferreira R, Franco-Penteado CF, Traina F, Sakamoto TM, Saad ST, et al. Participation of the Mac-1, LFA-1 and VLA-4 integrins in the in vitro adhesion of sickle cell disease neutrophils to endothelial layers, and reversal of adhesion by simvastatin. Haematologica. 2011 [Epub ahead of print].Google Scholar