miRNAs as biofluid markers for diagnostics of Alzheimer’s disease: recent status and perspectives

Abstract

After many decades of research in the field of neurodegeneration, we have no effective cure for Alzheimer's disease (AD), a major form of dementia. It is mainly due to the lack of early, reliable and sensitive biomarkers and incomplete understanding of disease mechanisms at molecular level. Several recently employed biomarkers, especially their combinations, can discriminate advanced stages of AD from other forms of dementia or neuropathy. They do not provide much information on molecular mechanisms of disease, rather they reflect the amount of key histopathological markers in the diseased brain. This review is focussed on novel class of potentially very promising AD biomarkers: extracellular miRNAs in body liquids, such as cerebrospinal fluid and blood. Those have a great potential not only to indicate the presence of AD, but more importantly, to reflect the molecular mechanisms playing a role early at the beginning of the pathogenic pathways consequently leading to AD. We believe this comprehensive review on deregulated miRNAs in AD can be a good source of information for thorough in silico analyses aiming to identify, develop and validate of miRNAs as "diseases mechanism engaged" candidate biomarkers. Having such molecules could bring us closer to the goal-successful treatment of AD.

Analysis of Circular RNA Expression Profile in HEK 293T Cells Exposed to Ionizing Radiation

“…A total of 5592 circRNAs were identified and there were 1038 novel circRNAs. Among the 5592 circRNAs, some were verified to be associated with diseases, such as Alzheimer disease 16 and B-cell chronic lymphocytic leukemia. 17 A total of 5592 circRNAs were located in all the chromosomes, including the mitochondrial chromosomes.…”

Extracellular RNA in Alzheimer’s disease

“…Further reviews have reiterated the heterogeneity in results and the consequent difficulty in establishing meaningful AD miRNA biomarkers (8,(105)(106)(107)(108). Reflecting on this challenge, Kosikova et al report miRNA biomarker panels, comprising anything between two and thirteen different miRNAs.…”

“…Some of these panels have reached 95% accuracy in detecting AD samples. However, the authors and others note the technical difficulties in validating miRNA hits from next generation sequencing, which may lead to the high number of contradictory findings in the literature (106,109). The accuracy of miRNA biomarker panels may be improved by concomitant analysis of the CSF Aβ: tau ratio (110).…”