Identification of Altered Blood MicroRNAs and Plasma Proteins in a Rat Model of Parkinson's Disease

Parkinson's disease (PD) is the age-related neurological disorder characterized by the degeneration of dopamine (DA) neurons in the substantia nigra pars compacta (SNpc). PD is based on motor deficits which start to appear when up to 80% of the DA neurons of SNpc have been lost. Effective management of PD requires the development of novel biomarkers. Therefore, the present study aimed to characterize biomarkers of PD using miRNomics, proteomics, and bioinformatics approaches. Rats exposed to rotenone (2.5 mg/kg b.wt) for 2 months were used as an animal model to identify the unbiased set of miRNAs and proteins deregulated in blood samples. OpenArray, a real-time PCR-based array, is used for high-throughput profiling of miRNAs, and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to carry out the global protein profiling. Systematic bioinformatics analysis of miRNAs and proteins was also performed, including annotation, functional classification and functional enrichment, network analysis, and miRNA-protein interaction analysis. Expression of 19 miRNAs and 96 proteins was significantly upregulated in the blood, while 22 proteins were significantly downregulated in blood samples of rotenone-exposed rats. In silico pathway analysis of deregulated proteins and miRNAs in rotenone-exposed rats has identified multiple pathways leading to PD. In summary, we have identified a set of miRNAs (miR-144, miR-96, and miR-29a) and proteins (PLP1, TUBB4A, and TUBA1C), which can be used as a potential biomarker of PD, while further validation required large human population studies.

Precision Medicine in Neurodegenerative Diseases: Some Promising Tips Coming from the microRNAs' World

: Novel insights in the development of a precision medicine approach for treating the neurodegenerative diseases (NDDs) are provided by emerging advances in the field of pharmacoepigenomics. In this context, microRNAs (miRNAs) have been extensively studied because of their implication in several disorders related to the central nervous system, as well as for their potential role as biomarkers of diagnosis, prognosis, and response to treatment. Recent studies in the field of neurodegeneration reported evidence that drug response and efficacy can be modulated by miRNA-mediated mechanisms. In fact, miRNAs seem to regulate the expression of pharmacology target genes, while approved (conventional and non-conventional) therapies can restore altered miRNAs observed in NDDs. The knowledge of miRNA pharmacoepigenomics may offers new clues to develop more effective treatments by providing novel insights into interindividual variability in drug disposition and response. Recently, the therapeutic potential of miRNAs is gaining increasing attention, and miRNA-based drugs (for cancer) have been under observation in clinical trials. However, the effective use of miRNAs as therapeutic target still needs to be investigated. Here, we report a brief review of representative studies in which miRNAs related to therapeutic effects have been investigated in NDDs, providing exciting potential prospects of miRNAs in pharmacoepigenomics and translational medicine.

Plasma and White Blood Cells Show Different miRNA Expression Profiles in Parkinson's Disease

Parkinson's disease (PD) diagnosis is based on the assessment of motor symptoms, which manifest when more than 50% of dopaminergic neurons are degenerated. To date, no validated biomarkers are available for the diagnosis of PD. The aims of the present study are to evaluate whether plasma and white blood cells (WBCs) are interchangeable biomarker sources and to identify circulating plasma-based microRNA (miRNA) biomarkers for an early detection of PD. We profiled plasma miRNA levels in 99 L-dopa-treated PD patients from two independent data collections, in ten drug-naïve PD patients, and in unaffected controls matched by sex and age. We evaluated expression levels by reverse transcription and quantitative real-time PCR (RT-qPCR) and combined the results from treated PD patients using a fixed effect inverse-variance weighted meta-analysis. We revealed different expression profiles comparing plasma and WBCs and drug-naïve and L-dopa-treated PD patients. We observed an upregulation trend for miR-30a-5p in L-dopa-treated PD patients and investigated candidate target genes by integrated in silico analyses. We could not analyse miR-29b-3p, normally expressed in WBCs, due to the very low expression in plasma. We observed different expression profiles in WBCs and plasma, suggesting that they are both suitable but not interchangeable peripheral sources for biomarkers. We revealed miR-30a-5p as a potential biomarker for PD in plasma. In silico analyses suggest that miR-30a-5p might have a regulatory role in mitochondrial dynamics and autophagy. Further investigations are needed to confirm miR-30a-5p deregulation and targets and to investigate the influence of L-dopa treatment on miRNA expression levels.

Identification of a panel of five serum miRNAs as a biomarker for Parkinson's disease

BACKGROUND AND OBJECTIVE

Parkinson's disease (PD) is the second most common age-related neurodegenerative disorder after Alzheimer's disease. The aim of this work was to determine whether the differences of serum miRNAs profiling could distinguish PD patients from healthy individuals.

METHODS

We collected serum samples from 106 sporadic PD patients and 91 age/gender-matched healthy controls. Serum miRNAs were analysed by Solexa sequencing followed by a qRT-PCR examination. The qRT-PCR assay, which was divided into two phases, was used to validate the expression of miRNAs screened by Solexa sequencing. Receiver operating characteristic (ROC) curve analysis and clustering analysis were performed to determine the diagnostic usefulness of the selected miRNAs for PD.

RESULTS

In this study, we generated a profile of 5 serum miRNAs: miR-195 was up-regulated, and miR-185, miR-15b, miR-221 and miR-181a were down-regulated.

CONCLUSION

This group of five miRNAs can precisely distinguish PD patients from health individuals and may be used as a potential serum-based biomarker for the diagnosis of PD.

Molecular diagnostics of neurodegenerative disorders

Molecular diagnostics provide a powerful method to detect and diagnose various neurological diseases such as Alzheimer's and Parkinson's disease. The confirmation of such diagnosis allows early detection and subsequent medical counseling that help specific patients to undergo clinically important drug trials. This provides a medical pathway to have better insight of neurogenesis and eventual cure of the neurodegenerative diseases. In this short review, we present recent advances in molecular diagnostics especially biomarkers and imaging spectroscopy for neurological diseases. We describe advances made in Alzheimer's disease (AD), Parkinson's disease (PD), Amyotrophic lateral sclerosis (ALS) and Huntington's disease (HD), and finally present a perspective on the future directions to provide a framework for further developments and refinements of molecular diagnostics to combat neurodegenerative disorders.