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A pilot study of ex vivo human prefrontal RNA transcriptomics in Parkinson’s disease

ABSTRACT: Parkinson’s disease (PD) can dramatically change cortical neurophysiology. The molecular basis for PD-related cortical changes is unclear because gene expression data are usually derived from postmortem tissue collected at the end of a complex disease and they profoundly change in the minutes after death. Here, we studied cortical changes in tissue from the prefrontal cortex of living PD patients undergoing deep-brain stimulation implantation surgery. We examined 780 genes using the NanoString nCounter platform and found that 40 genes were differentially expressed between PD (n = 12) and essential tremor (ET; n = 9) patients. One of these 40 genes, STAT1, correlated with intraoperative 4-Hz rhythms and intraoperative performance of an oddball reaction-time task. Using a pre-designed custom panel of 780 targets, we compared these intraoperative data with those from a separate cohort of fresh-frozen tissue from the same frontal region in postmortem human PD donors (n = 6) and age-matched neurotypical controls (n = 6). This cohort revealed 279 differentially expressed genes. Fifteen of the 40 intraoperative PD-specific genes overlapped with postmortem PD-specific genes, including CALB2 and FOXP2. Transcriptomic analyses identified pathway changes in PD that had not been previously observed in postmortem cases. These molecular signatures of cortical function and dysfunction may help us better understand cognitive and neuropsychiatric aspects of PD.

ORGANISM(S): Homo sapiens

PROVIDER: GSE227990 | GEO | 2023/03/27

REPOSITORIES: GEO

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Project description:Background: Molecular adaptations in the striatum mediated by dopamine (DA) denervation or Levodopa (L-dopa) treatment have been implicated with the motor deficits found in Parkinsonâs disease (PD). Alterations in glutamatergic neurotransmission and anti-oxidant mechanisms are reported to play important roles in mediating these changes. However, the mechanisms mediating the molecular adaptations in the striatum are not well understood. In recent years, microRNAs (miRNAs) have been recognized as potent post-transcriptional regulators of gene expression with fundamental roles in numerous biological processes. miRNAs are known to influence the development and maintenance of striatal neurons. To determine the contribution of miRNAs in molecular adaptations found in PD, we screened the expression of 800 miRNAs in postmortem striatum samples obtained from PD and neurologically normal controls. We detected the expression of approximately 250 miRNAs in postmortem human putamen samples collected from patients with PD and healthy controls. There was an abundance of a subset of 17 miRNAs (10 up- and 7 down-regulated) differing substantially between PD and the control, suggesting that miRNAs are altered in the striatum during the course of PD. Computational analysis show that many of these miRNAs targets pro-inflammatory factors in the striatum. Therefore, we sought to detrmine the expression of experimentally validated pro-inflammatory transcripts in PD striatum. Methods: Using a digital gene expression platform to quantify 134 gene transcripts, we compared human postmortem putamen tissues from patients with PD and neurologically normal controls. Results: We identified deregulated expression of 10 gene transcripts (4 up- and 6 down-regulated mRNAs) in postmortem human putamen samples collected fromPD patients compared to controls. The expression of these genes negative correlates with the expression of many of the differentially epxressed miRNAs. Moreover, many of these genes are predicted targets of the differentially expressed miRNAs. Conclusions: We identified deregulated mRNAs most likely associated with anti-oxidant mechanims in PD striatum. This approach may provide insights into pathogenesis of the disease. Human postmortem putamen tissues from 12 patients with PD symptoms and 12 neurologically normal controls were used in the study. Samples were obtained from the Human Brain and Spinal Fluid Resource Center, Los Angeles, CA through NIH NeuroBioBank, and stored at -80Â°C until RNA isolation. Total RNA was extracted using the mirVana RNA isolation kit, following the manufacturerâs instructions (Ambion). Using 225ng total RNA, mRNA levels were assayed by direct digital detection using Nanostring nCounter assay kits (Nanostring Technologies).

Project description:Background: Molecular adaptations in the striatum mediated by dopamine (DA) denervation or Levodopa (L-dopa) treatment have been implicated with the motor deficits found in Parkinsonâ??s disease (PD). Alterations in glutamatergic neurotransmission and anti-oxidant mechanisms are reported to play important roles in mediating these changes. However, the mechanisms mediating the molecular adaptations in the striatum are not well understood. In recent years, microRNAs (miRNAs) have been recognized as potent post-transcriptional regulators of gene expression with fundamental roles in numerous biological processes. miRNAs are known to influence the development and maintenance of striatal neurons. Therefore, we sought to determine the genome-wide expression levels of miRNAs in PD striatal tissues. Methods: Using a digital gene expression platform to quantify miRNA levels, we compared the expression of 800 miRNAs in human postmortem putamen tissues from PD patients and controls. Results: We detected the expression of approximately 250 miRNAs in postmortem human putamen samples collected from patients with PD and healthy controls. There was an abundance of a subset of 17 miRNAs (10 up- and 7 down-regulated) differing substantially between PD and the control tissues. Conclusions: We identified deregulated miRNAs most likely associated with altered striatal functions found in PD. This approach may provide insight into pathogenesis and additional therapeutic targets for the development novel treatment strategies for the disease. Human postmortem putamen tissues from 12 patients with PD symptoms and 12 neurologically normal controls. Samples were obtained from the Human Brain and Spinal Fluid Resource Center, Los Angeles, CA through NIH NeuroBioBank, and stored at -80Â°C until RNA isolation. Total RNA was extracted using the miRVana RNA isolation kit, following the manufacturerâ??s instructions (Ambion). Using 225ng total RNA, miRNA levels were assayed by direct digital detection using Nanostring miRNA assay kits (Nanostring Technologies).

Project description:Background: Molecular adaptations in the striatum mediated by dopamine (DA) denervation or Levodopa (L-dopa) treatment have been implicated with the motor deficits found in Parkinson’s disease (PD). Alterations in glutamatergic neurotransmission and anti-oxidant mechanisms are reported to play important roles in mediating these changes. However, the mechanisms mediating the molecular adaptations in the striatum are not well understood. In recent years, microRNAs (miRNAs) have been recognized as potent post-transcriptional regulators of gene expression with fundamental roles in numerous biological processes. miRNAs are known to influence the development and maintenance of striatal neurons. To determine the contribution of miRNAs in molecular adaptations found in PD, we screened the expression of 800 miRNAs in postmortem striatum samples obtained from PD and neurologically normal controls. We detected the expression of approximately 250 miRNAs in postmortem human putamen samples collected from patients with PD and healthy controls. There was an abundance of a subset of 17 miRNAs (10 up- and 7 down-regulated) differing substantially between PD and the control, suggesting that miRNAs are altered in the striatum during the course of PD. Computational analysis show that many of these miRNAs targets pro-inflammatory factors in the striatum. Therefore, we sought to detrmine the expression of experimentally validated pro-inflammatory transcripts in PD striatum. Methods: Using a digital gene expression platform to quantify 134 gene transcripts, we compared human postmortem putamen tissues from patients with PD and neurologically normal controls. Results: We identified deregulated expression of 10 gene transcripts (4 up- and 6 down-regulated mRNAs) in postmortem human putamen samples collected fromPD patients compared to controls. The expression of these genes negative correlates with the expression of many of the differentially epxressed miRNAs. Moreover, many of these genes are predicted targets of the differentially expressed miRNAs. Conclusions: We identified deregulated mRNAs most likely associated with anti-oxidant mechanims in PD striatum. This approach may provide insights into pathogenesis of the disease.

Project description:Parkinson's disease (PD) is a chronic progressive neurodegenerative disorder that is clinically defined in terms of motor symptoms. These are preceded by prodromal non-motor manifestations that prove the systemic nature of the disease. Identifying genes and pathways altered in living patients provide new information on the diagnosis and pathogenesis of sporadic PD. We study changes in gene expression in the blood of 40 sporadic PD patients and 20 healthy controls (Discovery set?) by taking advantage of the Affymetrix platform. Patients were at the onset of motor symptoms and before initiating any pharmacological treatment. By applying Ranking-Principal Component Analysis, PUMA and Significance Analysis of Microarrays, gene expression profiling discriminates patients from healthy controls and identifies differentially expressed genes in blood. The majority of these are also present in dopaminergic neurons of the Substantia Nigra, the key site of neurodegeneration. Together with neuronal apoptosis, lymphocyte activation and mitochondrial dysfunction, already found in previous analysis of PD blood and post-mortem brains, we unveiled transcriptome changes enriched in biological terms related to epigenetic modifications including chromatin remodeling and methylation. Candidate transcripts were validated by RT-qPCR in an independent cohort of 12 patients and controls (?Validation set). Our data support the use of blood transcriptomics to study neurodegenerative diseases. It identifies changes in crucial components of chromatin remodeling and methylation machineries as early events in sporadic PD suggesting epigenetics as target for therapeutic intervention. Analyzed samples include blood samples from 40 PD patients and 20 healthy controls. Of the original 60 samples, one (a control sample) did not pass the microarray hybridization quality controls and was excluded from further analyses. All results of bioinformatics analyses shown in this study refer to this set of 59 samples (reported here).

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A pilot study of ex vivo human prefrontal RNA transcriptomics in Parkinson’s disease

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