title: Small interfering RNA-mediated knockdown of protein kinase C zeta attenuates domoic acid-induced cognitive deficits in mice.
abstract: Accumulated evidence indicates that domoic acid (DA)-induced excitatory neuronal injury is associated with excessive reactive oxygen species (ROS) production. Protein kinase C zeta (PKC-ζ)/nicotinamide adenine dinucleotide phosphate (NOX) signaling regulates ROS levels and is involved in various neurodegenerative disorders including excitoneurotoxicity. Our previous studies have demonstrated that ROS-induced activation of the stress-activated protein kinase/c-jun-N-terminal kinase (SAPK/JNK) pathway plays a key role in the pathogenesis of cognitive deficits induced by DA. However, the precise biological mechanisms underlying these effects are not well understood. In this study, we investigate whether the PKC-ζ mediates DA-induced cognitive deficits and further explored the potential molecular processes. DA treatment significantly increased the expression of PI3K p85α, and PKC-ζ in the hippocampus of mice, which promoted the p47phox phosphorylation and expression, enhanced NOX activity, and increased the levels of ROS and protein carbonyls. In turn, the abnormal ROS levels in the hippocampus of DA-treated mice activated SAPK/JNK pathway, decreased FoxO1 phosphorylation, stimulated the nuclear translocation of FoxO1, activated FasL/Fas signaling, and promoted the activation of caspase-8 and caspase-3, which resulted in neuron apoptosis and cognitive deficits in mice. However, PKC-ζ knockdown reversed these changes in mice. It was further demonstrated that FoxO1 was a downstream target of SAPK/JNK signaling by FoxO1 small interfering RNA and SP600125 (an inhibitor of SAPK/JNK pathway) treatment. Additionally, SP600125 treatment or FoxO1 knockdown also blocked FasL/Fas signaling-dependent apoptosis and improved DA-induced cognitive deficits in the hippocampus of mice. These results suggest that PKC-ζ could be a possible target for the prevention or treatment of cognitive deficits in excitotoxic and other brain disorders.
authors.affiliation: Department of Environmental Engineering, School of Environment and Spatial Informatics, China University of Mining and Technology, Xuzhou, Jiangsu Province 221008, People's Republic of China.
authors.forename: Dong-mei
authors.initials: DM
authors.lastname: Wu
authors.forename: Jun
authors.initials: J
authors.lastname: Lu
authors.forename: Yuan-lin
authors.initials: YL
authors.lastname: Zheng
authors.forename: Yan-qiu
authors.initials: YQ
authors.lastname: Zhang
authors.forename: Bin
authors.initials: B
authors.lastname: Hu
authors.forename: Wei
authors.initials: W
authors.lastname: Cheng
authors.forename: Zi-feng
authors.initials: ZF
authors.lastname: Zhang
authors.forename: Meng-qiu
authors.initials: MQ
authors.lastname: Li
mesh_terms: D000818:Animals; D001483:Base Sequence; D001522:Behavior, Animal / Q000187:drug effects; D003072:Cognition Disorders / Q000139:chemically induced*; D017931:DNA Primers; D055785:Gene Knockdown Techniques; D007608:Kainic Acid / Q000031:analogs & derivatives* / Q000633:toxicity; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D011493:Protein Kinase C / Q000235:genetics*; D034741:RNA, Small Interfering / Q000235:genetics*; D000099221:Protein Kinase C zeta
chemical_list: D017931:DNA Primers; D007608:Kainic Acid; D011493:Protein Kinase C; D034741:RNA, Small Interfering; D000099221:Protein Kinase C zeta; C012301:domoic acid