title: DSM-RX78, a new phosphodiesterase inhibitor, suppresses superoxide anion production in activated human neutrophils and attenuates hemorrhagic shock-induced lung injury in rats.
abstract: Neutrophils are activated following hemorrhagic shock and the accumulation of neutrophils in the lung is associated with lung injury. This research investigated the effects of a semisynthetic 2-benzoylaminobenzoic acid derivative, methyl 2-(2-fluorobenzamido)benzoate (DSM-RX78), on superoxide anion (O(2)(-)) production in formyl-l-methionyl-l-leucyl-l-phenylalanine (FMLP)-activated human neutrophils, and on lung injury in Sprague-Dawley rats subjected to trauma-hemorrhage. DSM-RX78 concentration-dependently inhibited O(2)(-) production, but not elastase release, in FMLP-activated human neutrophils. DSM-RX78 displayed no superoxide-scavenging ability, and it failed to alter the subcellular NADPH oxidase activity. Significantly, DSM-RX78 increased cAMP formation and protein kinase (PK)A activity in FMLP-activated neutrophils, which occurred through the selective inhibition of cAMP-specific phosphodiesterase (PDE) activity but not an increase in adenylate cyclase function or cGMP-specific PDE activity. These results show that DSM-RX78 is a new inhibitor of cAMP-specific PDE. Moreover, DSM-RX78 reduced FMLP-induced phosphorylation of protein kinase B (Akt), but not calcium mobilization. The inhibitory effects of DSM-RX78 on O(2)(-) production and Akt phosphorylation were reversed by PKA inhibitors, suggesting that DSM-RX78 regulates O(2)(-) production of human neutrophils by promoting cAMP/PKA-dependent inhibition of Akt activation. On the other hand, administration of DSM-RX78 significantly attenuated the increase in myeloperoxidase activity and edema in the lung, as well as protein concentrations in bronchoalveolar lavage fluid in rats after trauma-hemorrhagic shock. In summary, these results strongly suggest that DSM-RX78 exerts anti-inflammatory effects, which result from the elevation of cAMP levels and PKA activity through its inhibition of cAMP-specific PDE. Also, our findings show that DSM-RX78 attenuates hemorrhagic shock-induced lung injury in rats.
authors.affiliation: Department of Anesthesiology, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan; College of Medicine, Chang Gung University, Taoyuan 333, Taiwan.
authors.forename: Huang-Ping
authors.initials: HP
authors.lastname: Yu
authors.forename: Pei-Wen
authors.initials: PW
authors.lastname: Hsieh
authors.forename: Yi-Ju
authors.initials: YJ
authors.lastname: Chang
authors.forename: Pei-Jen
authors.initials: PJ
authors.lastname: Chung
authors.forename: Liang-Mou
authors.initials: LM
authors.lastname: Kuo
authors.forename: Tsong-Long
authors.initials: TL
authors.lastname: Hwang
mesh_terms: D000328:Adult; D000818:Animals; D001549:Benzamides / Q000737:chemistry / Q000494:pharmacology*; D001565:Benzoates / Q000737:chemistry / Q000494:pharmacology*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D000242:Cyclic AMP / Q000096:biosynthesis; D017868:Cyclic AMP-Dependent Protein Kinases / Q000032:analysis / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D020128:Inhibitory Concentration 50; D019272:Leukocyte Elastase / Q000037:antagonists & inhibitors / Q000378:metabolism; D055370:Lung Injury / Q000209:etiology*; D008213:Lymphocyte Activation / Q000187:drug effects; D008297:Male; D015394:Molecular Structure; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology; D010726:Phosphodiesterase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D011506:Proteins / Q000032:analysis; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D016897:Respiratory Burst; D012771:Shock, Hemorrhagic / Q000378:metabolism*; D013481:Superoxides / Q000037:antagonists & inhibitors*
chemical_list: D001549:Benzamides; D001565:Benzoates; D010726:Phosphodiesterase Inhibitors; D011506:Proteins; C544338:methyl 2-(2-fluorobenzamido)benzoate; D013481:Superoxides; D009240:N-Formylmethionine Leucyl-Phenylalanine; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D019272:Leukocyte Elastase