Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
22
pubmed:dateCreated
2005-5-30
pubmed:abstractText
Oxidative modification of cytoplasmic RNA in vulnerable neurons is an important, well documented feature of the pathophysiology of Alzheimer disease. Here we report that RNA-bound iron plays a pivotal role for RNA oxidation in vulnerable neurons in Alzheimer disease brain. The cytoplasm of hippocampal neurons showed significantly higher redox activity and iron(II) staining than age-matched controls. Notably, both were susceptible to RNase, suggesting a physical association of iron(II) with RNA. Ultrastructural analysis further suggested an endoplasmic reticulum association. Both rRNA and mRNA showed twice the iron binding as tRNA. rRNA, extremely abundant in neurons, was considered to provide the greatest number of iron binding sites among cytoplasmic RNA species. Interestingly, the difference of iron binding capacity disappeared after denaturation of RNA, suggesting that the higher order structure may contribute to the greater iron binding of rRNA. Reflecting the difference of iron binding capacity, oxidation of rRNA by the Fenton reaction formed 13 times more 8-hydroxyguanosine than tRNA. Consistent with in situ findings, ribosomes purified from Alzheimer hippocampus contained significantly higher levels of RNase-sensitive iron(II) and redox activity than control. Furthermore, only Alzheimer rRNA contains 8-hydroxyguanosine in reverse transcriptase-PCR. Addressing the biological significance of ribosome oxidation by redox-active iron, in vitro translation with oxidized ribosomes from rabbit reticulocyte showed a significant reduction of protein synthesis. In conclusion these results suggest that rRNA provides a binding site for redox-active iron and serves as a redox center within the cytoplasm of vulnerable neurons in Alzheimer disease in advance of the appearance of morphological change indicating neurodegeneration.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
3
pubmed:volume
280
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
20978-86
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:15767256-Alzheimer Disease, pubmed-meshheading:15767256-Amino Acid Motifs, pubmed-meshheading:15767256-Animals, pubmed-meshheading:15767256-Binding Sites, pubmed-meshheading:15767256-Blotting, Northern, pubmed-meshheading:15767256-Brain, pubmed-meshheading:15767256-Cattle, pubmed-meshheading:15767256-Cytoplasm, pubmed-meshheading:15767256-Guanosine, pubmed-meshheading:15767256-Hippocampus, pubmed-meshheading:15767256-Humans, pubmed-meshheading:15767256-Hydrogen Peroxide, pubmed-meshheading:15767256-Image Processing, Computer-Assisted, pubmed-meshheading:15767256-Immunoprecipitation, pubmed-meshheading:15767256-Iron, pubmed-meshheading:15767256-Microscopy, Electron, pubmed-meshheading:15767256-Neurons, pubmed-meshheading:15767256-Oxidation-Reduction, pubmed-meshheading:15767256-Oxygen, pubmed-meshheading:15767256-Protein Biosynthesis, pubmed-meshheading:15767256-RNA, pubmed-meshheading:15767256-RNA, Ribosomal, pubmed-meshheading:15767256-RNA, Transfer, pubmed-meshheading:15767256-Reverse Transcriptase Polymerase Chain Reaction, pubmed-meshheading:15767256-Ribonucleases, pubmed-meshheading:15767256-Ribosomes
pubmed:year
2005
pubmed:articleTitle
Ribosomal RNA in Alzheimer disease is oxidized by bound redox-active iron.
pubmed:affiliation
Institute of Pathology, Case Western Reserve University, Cleveland, Ohio 44106, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural