Ischemic preconditioning protects the brain against injury via inhibiting CaMKII–nNOS signaling pathway

• Published in: Brain research 2016-03, Vol.1634, p.140-149
• Main Authors: Wang, Mei, Qi, Da-Shi, Zhou, Cui, Han, Dong, Li, Pei-Pei, Zhang, Fang, Zhou, Xiao-Yan, Han, Meng, Di, Jie-Hui, Ye, Jun-Song, Yu, Hong-Min, Song, Yuan-Jian, Zhang, Guang-Yi
• Format: Article
• Language: English
• Subjects: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine - analogs & derivatives; 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine - pharmacology; Animals; Apoptosis - drug effects; Brain Ischemia - metabolism; c-Jun; CA1 Region, Hippocampal - drug effects; CA1 Region, Hippocampal - metabolism; Calcium-Calmodulin-Dependent Protein Kinase Type 2 - antagonists & inhibitors; Calcium-Calmodulin-Dependent Protein Kinase Type 2 - metabolism; CaMKII; Disks Large Homolog 4 Protein; Fas Ligand Protein - metabolism; FasL; Intracellular Signaling Peptides and Proteins - metabolism; Ischemic Preconditioning; JNK Mitogen-Activated Protein Kinases - metabolism; Male; Membrane Proteins - metabolism; Neurology; Neurons - drug effects; Neurons - metabolism; Neuroprotection; Nitric Oxide Synthase Type I - metabolism; nNOS; Phosphorylation; PSD95; Rats; Rats, Sprague-Dawley; Reperfusion Injury - metabolism; Signal Transduction - drug effects
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2016.01.008

Abstract Although studies have shown that cerebral ischemic preconditioning (IPC) can ameliorate ischemia/reperfusion (I/R) induced brain damage, but its precise mechanisms remain unknown. Therefore, the aim of this study was to investigate the neuroprotective mechanisms of IPC against ischemic brain damage induced by cerebral I/R and to explore whether the Calcium/calmodulin-dependent protein kinase II (CaMKII)-mediated up-regulation of nNOS ser847-phosphorylation signaling pathway contributed to the protection provided by IPC. Transient global brain ischemia was induced by 4-vessel occlusion in adult male Sprague-Dawley rats. The rats were pretreated with 3 min of IPC alone or KN62 (selective antagonist of CaMKII) treatment before IPC, after reperfusion for 3 days, 6 min ischemia was induced. Cresyl violet staining was used to examine the survival of hippocampal CA1 pyramidal neurons. Immunoblotting was performed to measure the phosphorylation of CaMKII, nNOS, c-Jun and the expression of FasL. Immunoprecipitation was used to examine the binding between PSD95 and nNOS. The results showed that IPC could significantly protect neurons against cerebral I/R injury, furthermore, the combination of PSD95 and nNOS was increased, coinstantaneously the phosphorylation of CaMKII and nNOS (ser847) were up-regulated, however the activation of c-Jun and FasL were reduced. Conversely, KN62 treatment before IPC reversed all these effects of IPC. Taken together, the results suggest that IPC could diminish ischemic brain injury through CaMKII-mediated up-regulation of nNOS ser847-phosphorylation signaling pathway.