A Na+/Ca2+ exchanger isoform, NCX1, is involved in retinal cell death after N-methyl-D-aspartate injection and ischemia-reperfusion.
We investigated the expression of Na(+)/Ca(2+) exchanger (NCX) and the functional role of NCX in retinal damage by using NCX1-heterozygous deficient mice (NCX1(+/-)) and SEA0400 (2-[4-[(2,5-difluorophenyl)methoxy] phenoxy]-5-ethoxyaniline), a selective NCX inhibitor in vivo. We also examined the role of NCX in oxygen-glucose deprivation (OGD) stress with a retinal ganglion cell line (RGC-5) cell culture in vitro. The expression of NCX1 was confirmed and entirely localized in retina by immunoblotting and immunohistochemistry, respectively. NCX1(+/-) mice possessed significant protection against retinal damage induced by intravitreal injection of N-methyl-D-aspartate (NMDA). SEA0400 at 3 and 10 mg/kg significantly reduced NMDA- or high intraocular pressure-induced retinal cell damage in mice. Furthermore, SEA0400 reduced the number of TUNEL (terminal deoxynucleotidyl transferase dUTP nick-end labeling)-positive cells and the expression of phosphorylated mitogen-activated protein kinases (ERK1/2, JNK, p38) induced by NMDA injection. In RGC-5, SEA0400 at 0.3 and 1 microM significantly inhibited OGD-induced cell damage. OGD-induced cell damage was aggravated by ouabain (a Na(+),K(+)-ATPase inhibitor) at 100 microM, and this increased damage was significantly reduced by SEA0400 at 1 microM. In conclusion, these results suggest that NCX1 may play a role in retinal cell death induced by NMDA and ischemia-reperfusion.
Department of Biofunctional Evaluation, Molecular Pharmacology, Gifu Pharmaceutical University, Gifu, Japan.
Y
Y
Inokuchi
M
M
Shimazawa
Y
Y
Nakajima
I
I
Komuro
T
T
Matsuda
A
A
Baba
M
M
Araie
S
S
Kita
T
T
Iwamoto
H
H
Hara
D000814:Aniline Compounds / Q000494:pharmacology; D000818:Animals; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020287:In Situ Nick-End Labeling; D007429:Intraocular Pressure / Q000502:physiology; D015759:Ionomycin / Q000633:toxicity; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016202:N-Methylaspartate / Q000633:toxicity*; D018696:Neuroprotective Agents / Q000494:pharmacology; D009498:Neurotoxins / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D010647:Phenyl Ethers / Q000494:pharmacology; D051381:Rats; D015427:Reperfusion Injury / Q000503:physiopathology*; D012160:Retina / Q000166:cytology* / Q000187:drug effects; D012165:Retinal Ganglion Cells / Q000502:physiology*; D055351:Retinal Neurons / Q000502:physiology*; D019831:Sodium-Calcium Exchanger / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D013312:Stress, Physiological; D019284:Thapsigargin / Q000633:toxicity
D000814:Aniline Compounds; D004791:Enzyme Inhibitors; D018696:Neuroprotective Agents; D009498:Neurotoxins; D010647:Phenyl Ethers; C430918:SEA 0400; D019831:Sodium-Calcium Exchanger; C110374:sodium-calcium exchanger 1; D015759:Ionomycin; D010042:Ouabain; D016202:N-Methylaspartate; D019284:Thapsigargin; D020928:Mitogen-Activated Protein Kinases