miRNA-based signatures in cerebrospinal fluid as potential diagnostic tools for early stage Parkinson’s disease

Abstract

Parkinson’s Disease is the second most common neurodegenerative disorder, affecting 1–2% of the elderly population. Its diagnosis is still based on the identification of motor symptoms when a considerable number of dopaminergic neurons are already lost. The development of translatable biomarkers for accurate diagnosis at the earliest stages of PD is of extreme interest. Several microRNAs have been associated with PD pathophysiology. Consequently, microRNAs are emerging as potential biomarkers, especially due to their presence in Cerebrospinal Fluid and peripheral circulation. This study employed small RNA sequencing, protein binding ligand assays and machine learning in a cross-sectional cohort comprising 40 early stage PD patients and 40 well-matched controls. We identified a panel comprising 5 microRNAs (Let-7f-5p, miR-27a-3p, miR-125a-5p, miR-151a-3p and miR-423-5p), with 90% sensitivity, 80% specificity and 82% area under the curve (AUC) for the differentiation of the cohorts. Moreover, we combined miRNA profiles with hallmark-proteins of PD and identified a panel (miR-10b-5p, miR-22-3p, miR-151a-3p and α-synuclein) reaching 97% sensitivity, 90% specificity and 96% AUC. We performed a gene ontology analysis for the genes targeted by the microRNAs present in each panel and showed the likely association of the models with pathways involved in PD pathogenesis.

Circulating Brain‐Enriched MicroRNAs for Detection and Discrimination of Idiopathic and Genetic Parkinson's Disease

“…Of the 8 miRNAs that were differentially expressed between iPD and controls, 4 (50%) have been previously identified as deregulated in PD. These were miR-7-5p, 71 miR-22-3p, [72][73][74] miR-124-3p, 75 and miR-433-3p. 76 Another interesting finding is that the miRNAs found deregulated in genetic versus iPD cases were very different.…”

Circulating miRNAs as Diagnostic Biomarkers for Parkinson’s Disease

“…Shortcomings for biomarker research are the RNA input requirements for sequencing protocols as well as the still relatively high costs of NGS. Some studies demonstrate that downscaling is possible without losing sensitivity and specificity ( Burgos et al, 2013 , 2014 ; Rao et al, 2013 ; dos Santos et al, 2018 ). As NGS is still a relatively new technique and the solutions for small RNA sequencing are continuously improved, it is likely that this technique will be more widely available in the future.…”

“…Thereof, 6 miRNAs were further validated based on their involvement in related signaling pathways: miR-1, miR-19b-3p showed decreased expression in PD, while miR-153, miR-409-3p, miR-10a-5p, and let-7g-3p were found upregulated. A recent study reported that 5 miRNAs were able to differentiate between early stage PD and healthy controls: miR-151a-3p and let-7f-5p were up-regulated in PD CSF, whereas miR-27a-3p, miR-125a-5p, and miR-423-5p were significantly decreased ( dos Santos et al, 2018 ). The different studies performed with total CSF or CSF-exosomes show no overlapping results, even though the cohorts were of a comparable size.…”

<p>Functional Analysis of the 3ʹ Untranslated Region of the Human <em>GRIN1</em> Gene in Regulating Gene Expression in vitro</p>

“…53 Another study demonstrated that miR-423-5p in cerebrospinal fluid can be selected as one of the members of Parkinson's biomarker panel. 54 In the current study, we truncated the 3ʹUTR of the GRIN1 gene, and initially confirmed the potential functional sequence of the 3ʹ regulatory region of the GRIN1 gene by means of the luciferase reporter assay. Although bioinformatics tools showed the presence of multiple miRNA binding sites in the +295 bp -+ 497 bp region, including miR-212-5p, miR-324-3p and miR-326, further overexpression experiments did not directly demonstrate the regulatory effect of these miRNAs on GRIN1 gene expression.…”