Candesartan prevents angiotensin II-induced facilitation of hypoxic neuronal damage through PKCdelta inhibition.
To investigate the role of protein kinase Cdelta (PKCdelta) in angiotensin II-induced facilitation mechanisms of hypoxic neuronal damage and whether candesartan, an AT1 receptor antagonist, can suppress these mechanisms, we performed in vitro experiments which were free from vascular components using PC12 cells under hypoxic (12 h)/reoxygenation (0-48 h) conditions. Angiotensin II apparently increased the basal expression level of PKCdelta phosphorylated at Ser(643) before hypoxia, promoted the cleavage of PKCdelta to its catalytic fragment, and fostered the progression of DNA fragmentation after hypoxia. Candesartan inhibited both phosphorylation and cleavage of PKCdelta and suppressed the angiotensin II-induced facilitation of DNA fragmentation under hypoxic/reoxygenation conditions. However, PD123319, an AT2 receptor antagonist, influenced neither PKCdelta nor the angiotensin II-induced facilitation of DNA fragmentation. Furthermore, in PC12 cells expressing the ATP-binding mutant of PKCdelta (PKCdelta(K376R)) acting as a dominant-negative protein, both phosphorylation and cleavage of PKCdelta were attenuated and DNA fragmentation was markedly suppressed regardless of the presence of angiotensin II. These findings suggest that angiotensin II-induced facilitation of DNA fragmentation under hypoxic conditions is mediated by PKCdelta, and the mechanisms can be suppressed by the candesartan mediated blockade of the AT1 receptor.
Utsugisawa
Kimiaki
K
Department of Neurology, Iwate Medical University, Uchimaru 19-1, Morioka 020-8505, Japan. kutsugi@iwate-med.ac.jp
Nagane
Yuriko
Y
Utsugisawa
Taiju
T
Obara
Daiji
D
Terayama
Yasuo
Y
D000804:Angiotensin II / Q000037:antagonists & inhibitors*; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology*; D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology*; D001713:Biphenyl Compounds; D015153:Blotting, Western / Q000379:methods; D016923:Cell Death / Q000187:drug effects*; D015687:Cell Hypoxia / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005786:Gene Expression Regulation / Q000187:drug effects; D007093:Imidazoles / Q000494:pharmacology; D020287:In Situ Nick-End Labeling / Q000379:methods; D051379:Mice; D016716:PC12 Cells; D010766:Phosphorylation; D011493:Protein Kinase C / Q000502:physiology*; D051745:Protein Kinase C-delta; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D012694:Serine / Q000378:metabolism; D013777:Tetrazoles / Q000494:pharmacology*; D013997:Time Factors; D014162:Transfection / Q000379:methods
D047228:Angiotensin II Type 1 Receptor Blockers; D001562:Benzimidazoles; D001713:Biphenyl Compounds; D007093:Imidazoles; D011725:Pyridines; D013777:Tetrazoles; D000804:Angiotensin II; C073402:PD 123319; D012694:Serine; C497259:Prkcd protein, mouse; C497260:Prkcd protein, rat; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; C081643:candesartan