title: PDI regulates seizure activity via NMDA receptor redox in rats.
abstract: Redox modulation of cysteine residues is one of the post-translational modifications of N-methyl-D-aspartate receptor (NMDAR). Protein disulfide isomerases (PDI), an endoplasmic reticulum (ER) chaperone, plays a crucial role in catalyzing disulfide bond formation, reduction, and isomerization. In the present study, we found that PDI bound to NMDAR in the normal hippocampus, and that this binding was increased in chronic epileptic rats. In vitro thiol reductase assay revealed that PDI increased the amount of thiols on full-length recombinant NR1 protein. PDI siRNA, 5-5'-dithio-bis(2-nitrobenzoic acid) (DTNB), bacitracin and PDI antibody reduced seizure susceptibility in response to pilocarpine. In addition, PDI knockdown effectively ameliorated spontaneous seizure activity in chronic epileptic rats. Anticonvulsive effects of PDI siRNA were correlated to the reduction of the amount of free- and nitrosothiols on NMDAR, accompanied by the inhibition of PDI activity. However, PDI knockdown did not lead to alteration in basal neurotransmission or ER stress under physiological condition. These findings provide mechanistic insight into sulfhydration of disulfide bonds on NMDAR by PDI, and suggest that PDI may represent a target of potential therapeutics for epilepsy, which avoids a possible side effect on physiological receptor functionality.
authors.affiliation: Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon 24252, South Korea.
authors.forename: Ji Yang
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon 24252, South Korea.
authors.forename: Ah-Rhem
authors.initials: AR
authors.lastname: Ko
authors.affiliation: Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon 24252, South Korea.
authors.forename: Hye-Won
authors.initials: HW
authors.lastname: Hyun
authors.affiliation: Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon 24252, South Korea.
authors.forename: Su-Ji
authors.initials: SJ
authors.lastname: Min
authors.affiliation: Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon 24252, South Korea.
authors.forename: Ji-Eun
authors.initials: JE
authors.lastname: Kim
mesh_terms: D000818:Animals; D015415:Biomarkers; D004195:Disease Models, Animal; D004721:Endoplasmic Reticulum / Q000378:metabolism; D059865:Endoplasmic Reticulum Stress; D004827:Epilepsy / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D015870:Gene Expression; D055785:Gene Knockdown Techniques; D020022:Genetic Predisposition to Disease; D006624:Hippocampus / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D010084:Oxidation-Reduction; D010862:Pilocarpine / Q000009:adverse effects; D019704:Protein Disulfide-Isomerases / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics / Q000378:metabolism*; D012640:Seizures / Q000209:etiology / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D013438:Sulfhydryl Compounds / Q000378:metabolism
chemical_list: D015415:Biomarkers; D034741:RNA, Small Interfering; D016194:Receptors, N-Methyl-D-Aspartate; D013438:Sulfhydryl Compounds; D010862:Pilocarpine; D019704:Protein Disulfide-Isomerases