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β‐amyloid protein induces the formation of purine dimers in cellular DNA
Author(s) -
Duker Nahum J.,
Sperling Joseph,
Soprano Kenneth J.,
Druin Donald P.,
Davis Andrea,
Ashworth René
Publication year - 2001
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/1097-4644(20010601)81:3<393::aid-jcb1053>3.0.co;2-5
Subject(s) - xeroderma pigmentosum , dna damage , purine , dna , chemistry , amyloid (mycology) , biochemistry , deoxyguanosine , dna repair , senile plaques , dna oxidation , microbiology and biotechnology , biology , alzheimer's disease , medicine , pathology , enzyme , disease , inorganic chemistry
Experimental evidence implicates oxidative free radical reactions as central in the processes of neurodegenerative diseases. In particular, cellular interactions with the β‐amyloid protein have been linked to neuron cell death in Alzheimer's disease. Also, uncharacterized dimeric purine moieties have been detected in oxidized DNAs. It has been suggested that inadequate excision‐repair of such products plays a functional role in the neurological degeneration observed in familial Alzheimer's disease, Down's syndrome, and xeroderma pigmentosum. Therefore, in order to obtain a reagent to monitor the presence of such products, the purine dimer 8‐8‐(2′‐deoxyguanosyl)‐2′‐deoxyguanosine‐5′‐monophosphate was used as a hapten for elicitation of rabbit anti‐purine dimer antiserum. This antiserum specifically recognizes various purified 8‐8‐bideoxyribonucleosides and 8‐8‐bideoxyribonucleotides. We found that DNA oxidized by the Fenton reaction is specifically recognized by this antiserum. This reagent can therefore be used to demonstrate formation and excision of DNA purine dimers. Moreover, incubation of cultured rat pheochromocytoma PC‐12 cells with the β‐amyloid protein resulted in formation of these purine dimers in cellular DNA. These dimers were subsequently removed from cellular DNA. From these results we conclude that the free radicals generated by Aβ cause oxidative DNA alterations including purine dimers. Deficient repair of this type of DNA damage might result in neural cell loss via apoptosis. Our findings suggest mechanisms for the roles of β‐amyloid and oxidative free radicals in neurodegenerative diseases and the role of DNA excision‐repair in the prevention of lethal neurotoxicity. J. Cell. Biochem. 81:393–400, 2001. © 2001 Wiley‐Liss, Inc.