The study covered in this summary was published in ResearchSquare.com as a preprint and has not yet been peer reviewed.
miR-1976 is a possible new biomarker of Parkinson's disease.
Development of Parkinson's disease may be affected by PTEN-induced kinase 1 (PINK1), which was found to possibly be a target of miR-1976.
Why This Matters
Currently, diagnosis of Parkinson's disease generally occurs once motor symptoms have already developed and there has been significant loss of dopaminergic neurons.
The availability of biomarkers that might predispose individuals to a higher risk for Parkinson's disease may help in better understanding of the underlying pathology and lead to earlier diagnoses.
This was a case-controlled study with 23 patients with Parkinson's disease and 30 age- and sex-matched controls who had no neurologic conditions, diabetes, arthritis, or cardiac disease.
The animals in the study were C57/BL mice that received injections of miR-1976 mimic lentiviral vector to the substantia nigra neurons; they were killed 24 hours later.
The dopaminergic neuron cell line MES23.5 was cultured and prepared for transfection.
Blood samples from the participants were collected and analyzed for total RNA and miRNA using real-time polymerase chain reaction (PCR).
A luciferase assay was performed to identify whether PINK1 expression is regulated by miR-1976. To do this, the PINK1 3′-UTR was cloned into a luciferase reporter plasmid; then the ability of miR-1976 to inhibit expression of the PINK1 coding region was quantified.
Flow cytometry was used to observe cell apoptosis after transfection of the lentivirus vector.
Bioinformatics was used for analysis of miRNA for microarray expression profiling.
Gene ontology and pathway analysis were done to detected changes in functionally related genes.
Based on the bioinformatics analysis, 18 miRNAs were identified to be differentially regulated between the control group and the group with Parkinson's disease (P < .05); 11 of them were upregulated and seven were downregulated in the patients with Parkinson's disease vs the controls group
Real-time PCR showed that the expression of miR-1976 had the greatest difference between the patients with Parkinson's disease vs the controls. (P < .01).
The overexpression of miR-1976 on the apoptosis of the MES23.5 cells was confirmed both by PCR and flow cytometry.
In the mice model, miR-1976 induced more cell apoptosis bodies. The terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay also showed cell apoptosis in the group treated with the miR-1976 mimics.
Phosphatidylinositol 3-kinase (PIK3) was a predicted target of miR-1976.
Two pathways identified by the bioinformatics analysis (PINK1 and MAPK) were significantly associated with miR-1976 (P < .0001).
The high expression of miR-1976 inhibited the expression of PINK1 significantly (P < .05). However, this expression did not show a significant effect on the proteins of the MAPK signaling pathway.
There was one conserved miR-1976 cognate site harbored by PINK1 (89-91 of PINK1 3′ -UTR), which is a predicted target of miR-1976.
The luciferase assay showed that miR-1976 suppressed luciferase activity when the reporter plasmid carried the wild-type PINK1 3′-UTR. However, there was no significant suppression seen when the reporter plasmid carried a mutant PINK1 3′-UTR. This showed that the miR-1976 directly binds to the predicted binding site in the PINK1 3′-UTR.
Low expression of PINK1 stimulated more cell apoptosis in a time-dependent fashion, which indicated that inhibition of PINK1 regulated cell apoptosis. Additionally, the number of mitochondria and mitochondrial mass decreased with increased time, supporting this.
The authors did not identify any study limitations in their preprint.
The authors have no conflicts of interest.
The research was supported by Nanjing Medical Science and Technique Development Foundation.
This is a summary of a preprint research study, "miRNA-1976 Regulates Apoptosis Of Dopaminergic Neuron Cells by Targeting to PINK1," written by Feng Qiu, PhD, from Nanjing Brain Hospital, Nanjing Medical University, and colleagues, on Research Square provided to you by Medscape. This study has not yet been peer reviewed. The full text of the study can be found on ResearchSquare.com.
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Cite this: Expression of miR-1976 May Predispose to Parkinson’s Disease - Medscape - Jul 20, 2022.