Inhibition of nitric oxide-induced nuclear localization of CAPON by NMDA receptor antagonist in cultured rat primary astrocytes

• Published in: Neurochemistry international 2010-03, Vol.56 (4), p.561-568
• Main Authors: Jiang, Jing, Yan, Meijuan, Lv, Qingshan, Cheng, Chun, Li, Xiaohong, Guo, Zhiqin, Tao, Tao, Shen, Aiguo
• Format: Article
• Language: English
• Subjects: Adaptor Proteins, Signal Transducing - metabolism; Animals; Animals, Newborn; Astrocyte; Astrocytes - drug effects; Astrocytes - metabolism; Astrocytes - ultrastructure; Biological and medical sciences; Blotting, Western; CAPON; Cell Nucleus - drug effects; Cell Nucleus - metabolism; Cells, Cultured; Culture Media; Cytoplasm - drug effects; Cytoplasm - metabolism; Dizocilpine Maleate - pharmacology; Excitatory Amino Acid Antagonists - pharmacology; Fundamental and applied biological sciences. Psychology; Glial Fibrillary Acidic Protein - metabolism; Immunohistochemistry; Neuronal nitric oxide synthase; Nitric oxide; Nitric Oxide - antagonists & inhibitors; Nitric Oxide - biosynthesis; Nitric Oxide Donors - pharmacology; Nitroprusside - pharmacology; NMDA receptor; Rats; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate - agonists; Receptors, N-Methyl-D-Aspartate - antagonists & inhibitors; Reverse Transcriptase Polymerase Chain Reaction; RNA - biosynthesis; RNA - isolation & purification; Vertebrates: nervous system and sense organs
• ISSN: 0197-0186; 1872-9754
• DOI: 10.1016/j.neuint.2009.12.019

Astrocytes play a key role in regulating aspects of inflammation in the central nervous system. It was observed that nNOS had located in the nucleus of cultured cerebral cortical astrocytes of 7 days. In the present study, we found that carboxy-terminal PDZ ligand of nNOS (CAPON) mainly located in the nucleus of astrocytes stimulated with NO donor sodium nitroprusside (SNP) or GSNO or N-methyl- d-aspartate (NMDA) receptor agonist-NMDA. However, originally, it was localized mostly in the cytoplasm of normal astrocytes. Immunocytochemistry showed that nNOS was co-localized with CAPON in the nucleus of astrocytes stimulated with SNP. In addition to the nuclear localization, treatment with SNP increased the mRNA and protein expression of CAPON. When SNP was removed from media, CAPON accumulated in nucleus transported back to cytoplasm. MK801, an inhibitor of NMDA receptor, was able to reverse the nuclear localization of CAPON resulted from SNP, suggesting that there is a functional relationship of NO with NMDA receptor in the regulation of the nuclear localization of CAPON. These findings provide a new insight in the understanding of the physical and pathological significances of CAPON/nNOS/NMDA receptor.