Effects of KR-33028, a novel Na+/H+ exchanger-1 inhibitor, on glutamate-induced neuronal cell death and ischemia-induced cerebral infarct.
We investigated the effects of a novel Na(+)/H(+) exchanger-1 (NHE-1) inhibitor KR-33028 on glutamate excitotoxicity in cultured neuron cells in vitro and cerebral infarct in vivo by comparing its potency with that of zoniporide, a well-known, highly potent NHE-1 inhibitor. KR-33028 inhibited NHE-1 activation in a concentration-dependent manner (IC(50)=2.2 nM), with 18-fold greater potency than that of zoniporide (IC(50)=40.7 nM). KR-33028 significantly attenuated glutamate-induced LDH release with approximately 100 times lower EC(25) than that of zoniporide in cortical neurons in vitro (EC(25) of 0.007 and 0.81 microM, respectively), suggesting its 100-fold greater potency than zoniporide in producing anti-necrotic effect. In addition, the EC(50) of KR-33028 for anti-apoptotic effect was 100 times lower than that of zoniporide shown by TUNEL positivity (0.005 and 0.62 microM, respectively) and caspase-3 activity (0.01 and 2.64 microM, respectively). Furthermore, the EC(50) value of KR-33028 against glutamate-induced intracellular Ca(2+) overload was also 100 times lower than that of zoniporide (EC(50) of 0.004 and 0.65 microM, respectively). In the in vivo cerebral infarct model (60 min middle cerebral artery occlusion followed by 24 h reperfusion), KR-33028 reduced infarct size in a dose-dependent manner. Its ED(25) value, however, was quite similar to that of zoniporide (ED(25) of 0.072 and 0.097 mg/kg, respectively). Hence these results suggest that the novel NHE-1 inhibitor, KR-33028, could be an efficient therapeutic tool to protect neuronal cells against ischemic injury.
Lee
Bo Kyung
BK
Department of Physiology, Ajou University School of Medicine, Suwon 442-749, Republic of Korea.
Lee
Dong Ha
DH
Park
Sok
S
Park
Sung Lyea
SL
Yoon
Jae-Seok
JS
Lee
Min Goo
MG
Lee
Sunkyung
S
Yi
Kyu Yang
KY
Yoo
Sung Eun
SE
Lee
Kyung Hee
KH
Kim
You-Sun
YS
Lee
Soo Hwan
SH
Baik
Eun Joo
EJ
Moon
Chang-Hyun
CH
Jung
Yi-Sook
YS
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002545:Brain Ischemia; D053148:Caspase 3 / Q000378:metabolism; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D002544:Cerebral Infarction / Q000188:drug therapy / Q000473:pathology* / Q000503:physiopathology; D004789:Enzyme Activation / Q000187:drug effects; D018698:Glutamic Acid / Q000494:pharmacology*; D006146:Guanidines / Q000494:pharmacology*; D020287:In Situ Nick-End Labeling; D051379:Mice; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D009336:Necrosis; D009474:Neurons / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology; D018696:Neuroprotective Agents / Q000494:pharmacology*; D011720:Pyrazoles / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors*; D013876:Thiophenes / Q000494:pharmacology*
D006146:Guanidines; C507425:N-(4-cyano-benzo(b)thiophene-2-carbonyl)guanidine; D018696:Neuroprotective Agents; D011720:Pyrazoles; D017923:Sodium-Hydrogen Exchangers; D013876:Thiophenes; C069139:growth factor-activatable Na-H exchanger NHE-1; D018698:Glutamic Acid; C424422:zoniporide; D053148:Caspase 3