Nonredundant function of phosphodiesterases 4D and 4B in neutrophil recruitment to the site of inflammation.
Neutrophils have been implicated in the pathogenesis of many inflammatory lung diseases, including chronic obstructive pulmonary disease and asthma. With this study, we investigated how disruption of cAMP signaling impacts the function of neutrophil recruitment to the lung. Four genes code for type 4 phosphodiesterases (PDE4s), enzymes critical for regulation of cAMP levels and cell signaling. Ablation of two of these genes, PDE4B and PDE4D, but not PDE4A, has profound effects on neutrophil function. In a paradigm of mouse lung injury induced by endotoxin inhalation, the number of neutrophils recovered in the bronchoalveolar lavage was markedly decreased in PDE4D(-/-) and PDE4B(-/-) mice 4 and 24 h after exposure to LPS. Acute PDE4 inhibition with rolipram had additional inhibitory effects on neutrophil migration in PDE4B(-/-) and, to a lesser extent, PDE4D(-/-) mice. This decreased neutrophil recruitment occurred without major changes in chemokine accumulation in bronchoalveolar lavage, suggesting a dysfunction intrinsic to neutrophils. This hypothesis was confirmed by investigating the expression of adhesion molecules on the surface of neutrophils and chemotaxis in vitro. CD18 expression was decreased after ablation of both PDE4B and PDE4D, whereas CD11 expression was not significantly affected. Chemotaxis in response to KC and macrophage inflammatory protein-2 was markedly reduced in PDE4B(-/-) and PDE4D(-/-) neutrophils. The effect of PDE4 ablation on chemotaxis was comparable, but not additive, to the effects of acute PDE4 inhibition with rolipram. These data demonstrate that PDE4B and PDE4D play complementary, but not redundant, roles in the control of neutrophil function.
Ariga
Miyako
M
Division of Reproductive Biology, Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford, CA 94305, USA.
Neitzert
Barbara
B
Nakae
Susumu
S
Mottin
Genevieve
G
Bertrand
Claude
C
Pruniaux
Marie Pierre
MP
Jin
S-L Catherine
SL
Conti
Marco
M
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D000818:Animals; D002448:Cell Adhesion / Q000235:genetics / Q000276:immunology; D018925:Chemokines / Q000096:biosynthesis; D002634:Chemotaxis, Leukocyte / Q000235:genetics / Q000276:immunology; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000008:administration & dosage; D007249:Inflammation / Q000201:enzymology / Q000235:genetics / Q000276:immunology; D008070:Lipopolysaccharides / Q000008:administration & dosage; D008168:Lung / Q000201:enzymology* / Q000276:immunology / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D020556:Neutrophil Infiltration / Q000235:genetics / Q000276:immunology*; D029424:Pulmonary Disease, Chronic Obstructive / Q000201:enzymology / Q000235:genetics / Q000276:immunology; D020889:Rolipram / Q000008:administration & dosage; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D018925:Chemokines; D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; D020889:Rolipram