title: Calcium/calmodulin-dependent protein kinase II regulates the phosphorylation of CREB in NMDA-induced retinal neurotoxicity.
abstract: We examined the role of the phosphorylation of calcium/calmodulin-dependent protein kinase II (CaMKII) and cyclic AMP-response element binding protein (CREB) in N-methyl-d-aspartate (NMDA)-induced neurotoxicity in the rat retina. Western blot analysis showed early elevation of phosphorylated CaMKII (p-CaMKII) protein levels and subsequential elevation of phosphorylated CREB (p-CREB) protein after NMDA injection. Immunohistochemistry showed that p-CaMKII was colocalized with Thy-1-positive retinal ganglion cells (RGCs) after NMDA injection. The increase in the p-CaMKII protein level was significantly inhibited by the preinjection of CaMKII small interfering RNA (siRNA), whereas negative control siRNA did not affect. Moreover, the increase in the p-CREB protein level after NMDA injection was also prevented by preinjection of CaMKII siRNA. In addition, our morphometric study of neurotracer retrograde labeling and Thy-1-positive cells showed that CaMKII siRNA significantly accelerated NMDA-induced RGC loss. Furthermore, the prevention of CREB binding by CRE decoy oligonucleotide also exacerbated RGC loss. These results suggest that the activation of CaMKII may regulate CREB phosphorylation and that the transient phosphorylation of CaMKII and CREB may be a neuroprotective response against NMDA-induced neurotoxicity.
authors.affiliation: Department of Ophthalmology, St Marianna University School of Medicine, Kawasaki-Shi, Kanagawa, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takeda
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kitaoka
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Toshio
authors.initials: T
authors.lastname: Kumai
authors.forename: Yasunari
authors.initials: Y
authors.lastname: Munemasa
authors.forename: Hiromi
authors.initials: H
authors.lastname: Fujino
authors.forename: Shinichi
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Satoki
authors.initials: S
authors.lastname: Ueno
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000502:physiology*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000633:toxicity*; D005786:Gene Expression Regulation / Q000187:drug effects; D008297:Male; D016202:N-Methylaspartate / Q000633:toxicity*; D010766:Phosphorylation / Q000187:drug effects; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000166:cytology; D012165:Retinal Ganglion Cells / Q000187:drug effects*; D018800:Thy-1 Antigens / Q000378:metabolism; D013997:Time Factors
chemical_list: D017362:Cyclic AMP Response Element-Binding Protein; D004791:Enzyme Inhibitors; D018690:Excitatory Amino Acid Agonists; D034741:RNA, Small Interfering; D018800:Thy-1 Antigens; D016202:N-Methylaspartate; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2