Abstract
Tyrosine nitration of proteins at an extensive level is widely associated with the cognitive pathology induced by amyloid β peptide (Aβ). However, the precise identity and explicit consequences of protein nitration have scarcely been addressed. In this study, we examined the detectable nitration of proteins in the hippocampus of mice with cognitive impairment (day 5) induced by the i.c.v. injection of Aβ25–35 (day 0). The intensity of the nitration of proteins was inversely associated with the level of recognition memory in mice. The detectable tyrosine nitrations were revealed in proteins with a single size of approximately 70 kDa. The specific nitrated proteins at this size were identified using the liquid chromatography/mass spectrometry/mass spectrometry analysis and immunodetection methods. Intense nitration of the neurofilament light chain (NFL) was observed. The increased nitration of NFL was associated with its serine hyperphosphorylation and weak interaction with the nuclear distribution element-like, a protein essential for the stable assembly of neurofilaments. No changes in cell numbers in the hippocampus were found (day 5) in mice that received Aβ25–35 injections. These findings suggested that extensive nitration of NFL is associated with the Aβ-induced impairment of recognition memory in mice.
Footnotes
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This work was supported, in part, by the following: Japan-China Sasakawa Medical fellowship (to T.A.); Uehara Memorial Foundation fellowship for Foreign Researchers in Japan (to T.A.); grant-in-aid for the 21st Century Center of Excellence Program “Integrated Molecular Medicine for Neuronal and Neoplastic Disorders” and “Academic Frontier Project for Private Universities (2007–2011)” from the Ministry of Education, Culture, Sports, Science and Technology of Japan; Comprehensive Research on Aging and Health from the Ministry of Health, Labor and Welfare of Japan; Japan-Canada Joint Health Research Program and Japan-France Joint Health Research Program (Joint Project from Japan Society for the Promotion of Science); and International Research Project Supported by the Meijo Asian Research Center.
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Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
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doi:10.1124/jpet.108.141309
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ABBREVIATIONS: Aβ, amyloid β peptide; LC-MS/MS, liquid chromatography/mass spectrometry/mass spectrometry; NFL, neurofilament light chain; NUDEL, nuclear distribution element-like; NF, neurofilament; ONOO-, peroxynitrite; UA, uric acid; RIPA, radioimmunoprecipitation assay; PBS, phosphate-buffered saline; PAGE, polyacrylamide gel electrophoresis; PVDF, polyvinylidene difluoride; HSP70, heat shock protein 70; DRP-2, dihydropyrimidinase-like 2; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; SD, sodium dithionite; CBB, Coomassie Brilliant Blue; AD, Alzheimer's disease.
- Received May 19, 2008.
- Accepted July 9, 2008.
- The American Society for Pharmacology and Experimental Therapeutics
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