Absolute Quantification of Plasma MicroRNA Levels in Cynomolgus Monkeys, Using Quantitative Real-time Reverse Transcription PCR
February 12th, 2018
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This report describes a protocol for measuring the absolute levels of plasma miRNA, using quantitative real-time reverse transcription PCR with or without pre-amplification. This protocol affords better understanding of the quantity of plasma miRNAs and allows qualitative assessment of corresponding data from different studies or laboratories.
Overview
This report describes a protocol for measuring the absolute levels of plasma microRNAs using quantitative real-time reverse transcription PCR. This method allows for the assessment of plasma microRNAs even at low expression levels, facilitating comparisons across different studies.
Key Study Components
Area of Science
- Neuroscience
- Biomarker Research
- Molecular Biology
Background
- Plasma microRNAs play a crucial role in various biological processes.
- Understanding their levels can aid in identifying safety biomarkers.
- Standard curves can be generated for comparative analysis.
- This technique can be applied to samples from different species.
Purpose of Study
- To measure absolute levels of plasma microRNAs.
- To enable qualitative assessment of data across studies.
- To provide insights into translational research.
Methods Used
- Quantitative real-time reverse transcription PCR.
- Pre-amplification techniques may be employed.
- Thawing of frozen plasma samples from Cynomolgus Monkeys.
- Use of synthetic RNA for standard curve generation.
Main Results
- Effective measurement of low expression levels of plasma microRNAs.
- Facilitated comparison of results across different laboratories.
- Potential identification of safety biomarkers for translational research.
- Applicability to samples from various species.
Conclusions
- This protocol enhances the understanding of plasma microRNA levels.
- It supports the development of standardized methods for comparison.
- It opens avenues for further research in biomarker identification.
Frequently Asked Questions
What are plasma microRNAs?
Plasma microRNAs are small non-coding RNA molecules found in the blood that play roles in gene regulation.
Why is measuring plasma microRNAs important?
Measuring plasma microRNAs can provide insights into various diseases and help identify potential biomarkers for safety.
How does quantitative real-time PCR work?
Quantitative real-time PCR amplifies DNA and allows for the quantification of specific RNA sequences in real-time.
What is the significance of using a standard curve?
A standard curve allows for the comparison of results across different experiments and laboratories.
Can this method be applied to other species?
Yes, the method can be adapted for samples from various species using synthetic RNA for standardization.
Executive Industry Relevance
Absolute quantification of plasma microRNAs enables cross-study comparability and supports biomarker validation in preclinical safety assessment. This method enhances predictive confidence by providing quantitative, reproducible measurements of low-abundance targets in non-clinical species. It addresses a key gap in translational research where relative quantification limits data integration across laboratories and species.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Scientific Value: Enables hypothesis testing of miRNA-based safety biomarkers through absolute quantification in cynomolgus plasma.
- Operational Value: Uses synthetic cel-miR-238 as external control for normalization and quality assessment across sample batches.
- Predictive Value: Pre-amplification extends detection limit to 102 copies/µL, allowing measurement of low-expression miRNAs like miR-1, miR-206, and miR-499a.
Screening & Assay Development
- Assay Readiness: Probe-based RT-qPCR with miRNA-specific primers and probes enables specific, multiplexed detection of plasma miRNAs.
- Reproducibility: Technical variation estimated at less than 3-fold supports reliable longitudinal and inter-laboratory comparisons.
- Scalability: Standard curves from synthetic RNA oligonucleotides allow absolute quantification across concentration ranges for hit validation.
Translational & Preclinical Research
- Translational Continuity: Absolute quantification in cynomolgus monkeys supports extrapolation to human safety biomarker studies.
- Biomarker Qualification: Detectable miRNAs (miR-122, miR-133a, miR-192) without pre-amplification offer robust candidates for early safety screening.
- Risk Mitigation: Pre-amplification workflow enables detection of low-abundance miRNAs, reducing false negatives in biomarker panels.
Pipeline & Workflow Integration
The method fits within the discovery-to-preclinical continuum by enabling quantitative miRNA profiling that informs target selection and assay standardization.
- Discovery Biology: Absolute quantification supports mechanistic de-risking by providing copy-number data for miRNA target validation.
- Screening: LLOQ of 102 copies/µL enables screening-ready detection of both high and low-abundance plasma miRNAs.
- Analytics: Standard curve generation and Cq-based quantification allow statistical comparison of miRNA levels across treatment groups.
- Translational Research: Use of cynomolgus plasma and synthetic controls supports cross-species biomarker translation.
- Enterprise Reuse: Protocol defines reusable workflow for plasma miRNA quantification using RT-qPCR with optional pre-amplification.
Operational & Enterprise Impact
- Scientific Value: Absolute quantification reduces mechanistic ambiguity in miRNA biomarker studies.
- Operational Value: Standardized RNA extraction and qPCR workflow ensures reproducibility across sites.
- Strategic Value: Enables go/no-go decisions based on quantitative miRNA safety signals in preclinical models.
- Portfolio Impact: Risk-adjusted prioritization of miRNA biomarkers using absolute copy-number thresholds.
Implementation Considerations
- Requires expertise in RNA handling, RT-qPCR, and pre-amplification techniques.
- Dependent on access to thermocycler, vacuum manifold, and SDS software for data analysis.
- Needs standardization of plasma volume (200 µL EDTA) and external control (cel-miR-238) for cross-study consistency.
- Pre-amplification step necessary for miRNAs with Cq > 35 to avoid false-negative results.
- Limited to miRNAs with detectable amplification; miR-208a and miR-208b were not detectable even after pre-amplification.
Biopharma FAQs
Why does absolute quantification matter for plasma miRNA target validation?
Absolute quantification provides copy-number measurements that enable direct comparison of miRNA levels across studies, laboratories, and species, which is essential for validating miRNA-based safety biomarkers in preclinical development.
How does pre-amplification improve detection of low-abundance plasma miRNAs?
Pre-amplification extends the lower limit of quantification to 102 copies/µL, enabling detection of miRNAs like miR-1, miR-206, and miR-499a that would otherwise be undetectable due to high Cq values (>35) in direct RT-qPCR.
What role does the synthetic cel-miR-238 play in plasma miRNA quantification?
Synthetic cel-miR-238 serves as an external control to assess sample processing efficiency and normalization, with its Cq values used to evaluate RNA extraction and reverse transcription consistency across samples.
Why are standard curves necessary for absolute miRNA quantification in preclinical samples?
Standard curves generated from synthetic RNA oligonucleotides allow conversion of quantification cycle (Cq) values into absolute copy numbers, enabling quantitative comparison of miRNA expression across different experimental conditions.
What analytical capabilities are required to implement plasma miRNA quantification in a discovery setting?
Implementation requires quantitative real-time PCR instrumentation, software for Cq calculation (e.g., SDS v2.4), and tools like Excel to derive absolute copy numbers from standard curves, along with expertise in RNA extraction and pre-amplification workflows.
Chapters in this video
0:04
Title
1:01
RNA Extraction
3:43
cDNA Synthesis
4:55
Pre-amplification
6:02
Quantitative Real-time PCR
7:05
Data Analysis
7:27
Results: Use of Quantitative Real-time Reverse Transcription PCR with or without Pre-amplification to Measure the Absolute Levels of Plasma micro-RNAs
9:54
Conclusion
