BACKGROUND: Several previous reports have suggested an increased activity of cAMP phosphodiesterases (PDEs) and a higher sensitivity of these enzymes toward PDE inhibitors in leukocytes of patients suffering from atopic dermatitis. OBJECTIVE: The purpose of the present study was to comprehensively analyze and compare the PDE expression and activity profile of highly purified populations of leukocytes from normal and atopic blood donors. In addition, the influence of PDE inhibitors on function of leukocytes from normal and atopic individuals was investigated. METHODS: Density gradient centrifugation, elutriation, and magnetic cell sorting techniques were used to purify eosinophils, monocytes, and B and T lymphocytes from peripheral human blood. Complementary DNA-polymerase chain reaction was used to analyze PDE4 subtype messenger RNA (mRNA) expression levels in addition to PDE isoenzyme activities. PDE4 inhibitor sensitivity was determined in monocyte homogenates from both groups. Functionally, suppression of lipopolysaccharide-induced synthesis of tumor necrosis factor-alpha in monocytes as well as phytohemagglutinin-induced T cell proliferation in peripheral blood mononuclear cell fractions by PDE4 and PDE3/4 inhibitors was compared. RESULTS: Identical PDE activities and mRNA expression profiles were found in all cells from normal and atopic donors except that there was an increase in the mRNA levels of PDE4A and PDE4B2 in atopic T cells, which was, however, not reflected in overall PDE4A activity. In addition, no differences in sensitivity of the functional responses to PDE inhibitors were noted. The mixed PDE3/4 inhibitor zardaverine was a more potent inhibitor of T cell proliferation than rolipram, a selective PDE4 inhibitor. CONCLUSION: No evidence for alterations of PDE activities in atopy is provided by our findings.
BACKGROUND: Several previous reports have suggested an increased activity of cAMP phosphodiesterases (PDEs) and a higher sensitivity of these enzymes toward PDE inhibitors in leukocytes of patients suffering from atopic dermatitis. OBJECTIVE: The purpose of the present study was to comprehensively analyze and compare the PDE expression and activity profile of highly purified populations of leukocytes from normal and atopic blood donors. In addition, the influence of PDE inhibitors on function of leukocytes from normal and atopic individuals was investigated. METHODS: Density gradient centrifugation, elutriation, and magnetic cell sorting techniques were used to purify eosinophils, monocytes, and B and T lymphocytes from peripheral human blood. Complementary DNA-polymerase chain reaction was used to analyze PDE4 subtype messenger RNA (mRNA) expression levels in addition to PDE isoenzyme activities. PDE4 inhibitor sensitivity was determined in monocyte homogenates from both groups. Functionally, suppression of lipopolysaccharide-induced synthesis of tumor necrosis factor-alpha in monocytes as well as phytohemagglutinin-induced T cell proliferation in peripheral blood mononuclear cell fractions by PDE4 and PDE3/4 inhibitors was compared. RESULTS: Identical PDE activities and mRNA expression profiles were found in all cells from normal and atopic donors except that there was an increase in the mRNA levels of PDE4A and PDE4B2 in atopic T cells, which was, however, not reflected in overall PDE4A activity. In addition, no differences in sensitivity of the functional responses to PDE inhibitors were noted. The mixed PDE3/4 inhibitor zardaverine was a more potent inhibitor of T cell proliferation than rolipram, a selective PDE4 inhibitor. CONCLUSION: No evidence for alterations of PDE activities in atopy is provided by our findings.
Authors: L J Landells; C M Szilagy; N A Jones; K H Banner; J M Allen; A Doherty; B J O'Connor; D Spina; C P Page Journal: Br J Pharmacol Date: 2001-07 Impact factor: 8.739
Authors: C D Manning; M Burman; S B Christensen; L B Cieslinski; D M Essayan; M Grous; T J Torphy; M S Barnette Journal: Br J Pharmacol Date: 1999-12 Impact factor: 8.739
Authors: Madelyn S Hanson; Alan H Stephenson; Elizabeth A Bowles; Meera Sridharan; Shaquria Adderley; Randy S Sprague Journal: Am J Physiol Heart Circ Physiol Date: 2008-06-27 Impact factor: 4.733