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P2‐117: MICRO‐RNAS AS NOVEL BIOMARKERS IN AD: DIFFERENTIAL EXPRESSION IN HIPPOCAMPUS AND IN CELL‐FREE CEREBROSPINAL FLUID
Author(s) -
Verbeek Marcel M.,
Muller Mareike,
Kusters Benno,
Claassen Jurgen A.,
Kuiperij H. Bea
Publication year - 2014
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2014.05.792
Subject(s) - microrna , cerebrospinal fluid , biology , hippocampus , cell , pathology , neuroscience , medicine , gene , genetics
Background: The small, 19-22 nucleotides long micro-RNAs play a prominent role in regulating protein translation in cells. More than 700 miRNAs have been identified in humans, and approximately 70% is expressed in the brain. Therefore, miRNAs have been suggested as indicators for Alzheimer’s Disease (AD). Here, we aim to identify miRNAs that are differentially expressed in AD patients and non-demented controls as possible new biomarkers in both brain tissue and cerebrospinal fluid (CSF).Methods:QPCR was used to study miRNAs let-7f, miR9, miR16, miR34a, miR34c, miR107, miR128a and miR146a. We used hippocampus of 10 nondemented controls, 10 AD patients with Braak III/IV and 10 with Braak VI; and CSF of 20 AD and 20 non-demented controls. For CSF samples, a pre-amplification step was included to increase detection in qPCR. The effects of blood contamination on miRNAs levels was tested by spiking known numbers of blood cells into cell-free CSF. For expression studies, only CSF samples with no or a very low number of cells were selected. In CSF, U6 snRNA served as internal control. In hippocampus, let-7f was used as internal control, because this miRNA was abundantly and equally expressed in all samples. Relative expression levels (REL) were calculated with the formula 2 -DCt. Results: In hippocampus, miR16, miR34c, miR107, miR128a and miR146a were differentially regulated, which was dependent on the Braak stage. In Hela cells, MAP7 was identified as a potential miR16 target. In CSF, out of 8 selected miRNAs only miR16 and miR146a could be reliably detected. Levels of miR-146a were significantly decreased in CSF of AD patients. We identified a strong effect of blood contamination on the CSF levels of miR16, miR24, and miR146a. Conclusions: In conclusion, the abnormal expression of several miRNAs in hippocampus of intermediateand late-stage AD patients suggests their involvement in AD pathogenesis, and low levels of miR146a in CSF were associated with AD.