Suppression of postsynaptic density protein 95 by antisense oligonucleotides diminishes postischemic pyramidal cell death in rat hippocampal CA1 subfield.
Our previous investigation has shown that postsynaptic density protein 95 (PSD-95) is critical for the Src family kinases-mediated tyrosine phosphorylation of N-methyl-d-aspartate receptor subunit 2A (NR2A) in the postischemic hippocampus. To clarify the roles of PSD-95 in the ischemic brain damage, histological method was performed to examine the effects of PSD-95 antisense oligonucleotides (AS) on the postischemic delayed cell death in rat hippocampus. Transient (15 min) brain ischemia was induced by the four-vessel occlusion method in Sprague-Dawley rats. Five days of reperfusion following brain ischemia (I/R5d) led to hippocampal CA1 pyramidal cell death upward of 90%. Intracerebroventricular infusion of AS (every 24 h for 3 days before ischemia) not only decreased the PSD-95 expression but also increased the number of surviving pyramidal neurons, while missense oligonucleotides (MS) had no effects. To further investigate the mechanisms underlying the neuroprotection of PSD-95 deficiency, the interaction of proline-rich tyrosine kinase 2 (Pyk2) with NR2A as well as autophosphorylation (Tyr402) of Pyk2 were detected. Immunoprecipitation and immunoblot analysis showed that preischemic treatment with AS, but not MS or vehicle, attenuated the I/R6h-induced increases in Pyk2-NR2A association and Pyk2 autophosphorylation. The protein levels of NR2A and Pyk2 had no differences under the above conditions. Our data suggest that the recruitments of ion channels and signaling molecules may be involved in the PSD-95 neurotoxicity in the postischemic hippocampus.
Hou
Xiao-Yu
XY
Research Center for Biochemistry and Molecular Biology, Xuzhou Medical College, University of Science & Technology of China, 84 West Huai-hai Road, Xuzhou, Jiangsu 221002, PR China.
Zhang
Guang-Yi
GY
Wang
De-Guang
DG
Guan
Qiu-Hua
QH
Yan
Jing-Zhi
JZ
D000818:Animals; D002545:Brain Ischemia / Q000378:metabolism* / Q000473:pathology; D016923:Cell Death / Q000187:drug effects; D000076122:Disks Large Homolog 4 Protein; D051418:Focal Adhesion Kinase 2; D015151:Immunoblotting; D047468:Immunoprecipitation; D007276:Injections, Intraventricular; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins / Q000172:deficiency / Q000187:drug effects / Q000378:metabolism*; D018696:Neuroprotective Agents / Q000008:administration & dosage*; D016376:Oligonucleotides, Antisense / Q000008:administration & dosage*; D011505:Protein-Tyrosine Kinases / Q000187:drug effects; D017966:Pyramidal Cells / Q000187:drug effects* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects; D015427:Reperfusion Injury / Q000517:prevention & control
D000076122:Disks Large Homolog 4 Protein; D051418:Focal Adhesion Kinase 2; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D018696:Neuroprotective Agents; D016376:Oligonucleotides, Antisense; D011505:Protein-Tyrosine Kinases; D016194:Receptors, N-Methyl-D-Aspartate; C501449:Dlg4 protein, rat; C033652:postsynaptic density proteins; C496054:Ptk2b protein, rat