Lack of PSD-95 drives hippocampal neuronal cell death through activation of an alpha CaMKII transduction pathway.
The PSD-95 protein family organizes the glutamatergic postsynaptic density and it is involved in the regulation of the excitatory signal at central nervous system synapses. We show here that PSD-95 deficiency by means of antisense oligonucleotides induces significant neuronal cell death within 24 h both in primary hippocampal cultures and in organotypic hippocampal slices. On the other hand, cultured cortical neurons are spared by PSD-95 antisense toxicity until they reach a NR2A detectable protein level (24 days in vitro). The neurotoxic event is characterized by increased alpha CaMKII association to NR2 regulatory subunits of NMDA receptor complex. As a direct consequence of alpha CaMKII association, we found increased GluR1 delivery to cell surface in cultured hippocampal neurons paralleled by AMPA-dependent increase in [Na+]I levels. In addition, both CaMKII specific inhibitor KN-93 and AMPA receptor antagonists CNQX and NBQX rescued neuronal survival to control values. On the other hand, both the NMDA channel blocker MK-801 and Dantrolene, an inhibitor of calcium release from ryanodine-sensitive endoplasmic reticulum stores, failed to have any effect on neuronal survival in PSD-95 deficient neurons. Thus, our data provide clues that PSD-95 reduced expression in neurons is responsible for neuronal vulnerability mediated by direct activation of alpha CaMKII transduction pathway in the postsynaptic compartment.
Gardoni
Fabrizio
F
Center of Excellence on Neurodegenerative Diseases and Department of Pharmacological Sciences, University of Milano, via Balzaretti 9, 20133 Milano, Italy.
Bellone
Camilla
C
Viviani
Barbara
B
Marinovich
Marina
M
Meli
Elena
E
Pellegrini-Giampietro
Domenico E
DE
Cattabeni
Flaminio
F
Di Luca
Monica
M
D000818:Animals; D001596:Benzylamines / Q000494:pharmacology; D015153:Blotting, Western; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018929:Cell Culture Techniques; D016923:Cell Death; D002470:Cell Survival; D002540:Cerebral Cortex / Q000378:metabolism; D000076122:Disks Large Homolog 4 Protein; D015536:Down-Regulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins / Q000172:deficiency*; D009474:Neurons / Q000201:enzymology / Q000378:metabolism*; D016376:Oligonucleotides, Antisense; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D015398:Signal Transduction; D013449:Sulfonamides / Q000494:pharmacology; D000096926:Benzenesulfonamides
D001596:Benzylamines; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D000076122:Disks Large Homolog 4 Protein; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D016376:Oligonucleotides, Antisense; D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate; D013449:Sulfonamides; C501449:Dlg4 protein, rat; C033652:postsynaptic density proteins; C072105:KN 93; D000096926:Benzenesulfonamides