Protein kinase A-dependent suppression of reactive oxygen species in transient focal ischemia in adrenomedullin-deficient mice.
This study was designed to examine the effect of adrenomedullin deficiency on cerebral infarction and the relationship between adrenomedullin and cyclic AMP-protein kinase A pathway in regulating reactive oxygen species (ROS). Adrenomedullin heterozygous and wild-type mice were subjected to 60-mins focal ischemia. We used adrenomedullin heterozygous mice because adrenomedullin homozygotes die in utero. Infarct volume, neurologic deficit scores, and immunohistochemical analyses were evaluated at several time points after ischemia. The infarct volume and neurologic deficit scores were significantly worse in adrenomedullin heterozygous mice. Significant accumulation of inducible nitric oxide, oxidative DNA damage, and lipid peroxidation was noted after reperfusion in adrenomedullin heterozygous mice. Treatment of wild-type mice with H89, a protein kinase A inhibitor, resulted in increased infarct size, and worsening of neurologic deficit score and other parameters to levels comparable to those of adrenomedullin heterozygous mice. In contrast, cilostazol, which increases cyclic AMP, rescued neurologic deficit and ROS accumulation in adrenomedullin heterozygous mice. This study showed that adrenomedullin downregulation results in increase in ROS after transient focal ischemia in mice. The results also indicated that adrenomedullin has an important function against ischemic injury through the cyclic AMP-protein kinase A pathway.
Miyamoto
Nobukazu
N
Department of Neurology, Juntendo University School of Medicine, Bunkyou-ku, Tokyo, Japan.
Tanaka
Ryota
R
Shimosawa
Tatsuo
T
Yatomi
Yutaka
Y
Fujita
Toshiro
T
Hattori
Nobutaka
N
Urabe
Takao
T
D053607:Adrenomedullin / Q000172:deficiency* / Q000235:genetics / Q000502:physiology; D000818:Animals; D000077407:Cilostazol; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3 / Q000378:metabolism; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4 / Q000378:metabolism; D004195:Disease Models, Animal; D015536:Down-Regulation; D004591:Electrophoresis, Polyacrylamide Gel; D006579:Heterozygote; D015151:Immunoblotting; D007150:Immunohistochemistry; D002546:Ischemic Attack, Transient / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D007546:Isoquinolines / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000037:antagonists & inhibitors*; D013449:Sulfonamides / Q000494:pharmacology; D013777:Tetrazoles / Q000494:pharmacology
D007546:Isoquinolines; D010726:Phosphodiesterase Inhibitors; D017382:Reactive Oxygen Species; D013449:Sulfonamides; D013777:Tetrazoles; D053607:Adrenomedullin; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; D000077407:Cilostazol