Quantitative RNA Integrity Assessment via qPCR Segmentation
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Solution Overview
Problem
Current methods for assessing RNA integrity provide only qualitative, ordinal measurements, limiting their ability to accurately quantify RNA integrity and correct for degradation in mRNA expression analysis, which is crucial for diagnostic and prognostic applications.
Innovation Solution
A method that determines the quantitative integrity of RNA by assaying damaged RNA molecules, measuring the relative or absolute numbers of intact segments of different lengths, and using these measures to calculate a quantitative integrity score, which can then be used to correct mRNA expression levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If automated electrophoresis systems (Bioanalyzer, Experion) are used to assess RNA integrity, then automation and throughput are improved, but only ordinal qualitative measurements (RIN, RQI scores) are obtained rather than true quantitative data
Solution Approach 1:
The patent replaces the mechanical electrophoresis-based separation and visualization system with a quantitative PCR-based measurement system. Instead of using gel electrophoresis to separate RNA fragments and generate ordinal scores, the invention uses qPCR to directly quantify the number of intact RNA molecules at different degradation levels, providing true quantitative data while maintaining automation capability
Solution Approach 2:
The patent changes the measurement parameter from ordinal scoring (RIN 1-10) to quantitative molecular counts. By measuring the actual number of intact RNA molecules versus degraded fragments using qPCR amplification, the system transforms the output from a qualitative score to a precise quantitative metric that reflects true RNA integrity
2Reliability
If agarose gel-based electrophoresis is used to determine RNA degradation level, then RNA integrity can be assessed, but the method is variable, inaccurate, time consuming and cost intensive
Solution Approach 1:
The patent replaces the manual agarose gel electrophoresis process with an automated quantitative PCR system. This substitution eliminates the need for gel casting, loading, running, and imaging steps, reducing both time consumption and operational complexity while improving measurement accuracy through standardized amplification reactions
Solution Approach 2:
The patent introduces qPCR as an intermediary measurement method between RNA extraction and integrity assessment. Instead of directly visualizing RNA on gels, the system uses PCR amplification of specific RNA regions to indirectly measure integrity, providing a more sensitive, accurate, and efficient readout of RNA degradation status
3Ease of operation
If ordinal scoring systems (RIN, RQI) are used for RNA quality assessment, then quick qualitative evaluation is achieved, but accurate quantification of RNA integrity and correction for degradation in mRNA expression analysis is limited
Solution Approach 1:
The patent fundamentally changes the output parameter from ordinal scores (1-10 scale) to quantitative molecular measurements. By using qPCR to count actual RNA molecules at different degradation stages, the system provides precise quantitative data that can be directly used to correct mRNA expression levels, eliminating the information loss inherent in ordinal scoring
Data Source
AI summary
A method of determining a quantitative measure of the integrity of RNA in a sample, the method comprising: (i) assaying a sample containing instances of an RNA molecule transcribed from a reference gene, at least some of the instances being damaged, to determine quantitative measures of the relative or absolute numbers of intact instances of each of a plurality of segments of the RNA molecule in the sample, the segments having respective different lengths; (ii) based on a relationship between the determined quantitative measures and the respective different lengths of the segments, determining a quantitative measure of integrity of the instances of the RNA molecule in the sample; and (iii) determining the total number of instances of an RNA molecule of interest in a sample by using the quantitative measure of integrity and the length of a corresponding degradation-relevant segment of the RNA molecule of interest.