Objective/Rationale:
MicroRNAs (miRNAs) are small, conserved RNAs that interact with target sequences on messenger RNAs. MiRNAs have been proven to regulate the expression of many genes and play important roles in normal cell development and differentiation. We theorize that dying dopaminergic neurons of PD patients release biological and chemical contents, including miRNAs, into blood. We hypothesize that we can differentiate PD patients from normal healthy individuals based on a distinct set of dopaminergic neuronal circulating miRNAs in the plasma.
Project Description:
We will isolate and purify total RNA that includes miRNAs from plasma samples of PD patients and normal healthy controls to perform miRNA microarrays (Agilent). The K-Top Scoring Pairs (K-TSP) algorithm will be used to generate a highly discriminative classifier that distinguishes between PD and controls. All candidate miRNAs will be validated by Q-PCR on training samples in triplicate, using the Taqman microRNA assay. A panel of PD-predictive biomarkers will be developed after the validation. This panel will be tested in a new cohort of PD patients to validate its specificity and sensitivity.
Relevance to Diagnosis/Treatment of Parkinson’s Disease:
This project will facilitate the development of early detection for PD using a highly-specific, highly-sensitive, yet inexpensive and non-invasive assay. As a diagnostic tool, it will assist clinicians in choosing appropriate treatment and monitoring the progression of PD patients. In addition, the PD-predictive miRNAs are likely to uncover gene products with mechanistic properties of PD that can be pursued further as new targets for drug therapy.
Anticipated Outcome:
This is a proof-of-principle study to suggest that circulating miRNAs in the plasma can be used as predictive biomarkers for PD. The K-TSP algorithm has been proven feasible to handle small biological sample data sets and generate accurate classifiers. In this study, we anticipate to identify two to ten candidate miRNA biomarkers to be associated with PD that can lead us to early detection of this disease.
Final Outcome
During the course of Parkinson’s disease progression, dying dopaminergic neurons of PD patients release biological and chemical contents, including microRNA’s (miRNAs), into blood. We examined if it was possible to differentiate PD patients from normal healthy individuals based on a distinct set of dopaminergic neuronal circulating miRNAs in the plasma that could reflect the pace of disease progression and serve as a sensitive method for detection and diagnosis of PD. Circulating miRNAs in plasma of PD patients and healthy controls was obtained to acquire global miRNA expression profiles using microarray technology. Using SAM (Significant Analysis of Microarrays) and KTSP (K-Top Scoring Pairs) algorithms, we detected 13 significant differentially expressed miRNAs between PD and controls, as well as identified 9 miRNA pairs that can discriminate PD patients from controls. Real-Time PCR was performed to validate the miRNA expression and a set of PD-specific miRNAs that can discriminate PD patients from healthy controls was identified. These miRNAs will help facilitate the development of a PD-predictive miRNA panel for early detection and diagnostic purposes.