miRNA Expression Normalization Using Artificial RNA Mediators
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Solution Overview
Problem
Current methods for correcting miRNA expression levels in body fluids using DNA microarrays are inadequate, particularly when measuring a small number of miRNAs, as they lack accuracy due to the difficulty in detecting stable endogenous miRNAs in body fluids and the limitations of using housekeeping RNAs or mRNAs for normalization.
Innovation Solution
The method involves using a combination of specific endogenous miRNA capture probes to measure the expression levels of target miRNAs and correcting them using the signal values of one or more stably expressed endogenous miRNAs, which are naturally present in body fluids, to achieve accurate normalization and comparison across multiple samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If housekeeping RNAs (U1 snoRNA, U2 snoRNA, U3 snoRNA, U4 snoRNA, U5 snoRNA, U6 snoRNA, 5S rRNA, and 5.8S rRNA) are used for correcting miRNA expression levels in body fluids, then correction can be performed, but the expression levels of these RNAs cannot be detected in body fluids containing no cells, making them unsuitable for normalization
Solution Approach 1:
The patent introduces artificial RNA molecules as intermediary substances to serve as normalization controls in body fluid samples. These artificial RNAs are exogenously added to the samples and function as mediator references, allowing accurate normalization without relying on endogenous housekeeping RNAs that cannot be detected in cell-free body fluids. This intermediary approach bridges the gap between the need for normalization and the absence of suitable endogenous controls.
Solution Approach 2:
The patent changes the fundamental parameter of normalization from using endogenous RNAs (housekeeping RNAs) to using exogenously added artificial RNAs. This parameter change enables detection and normalization in body fluids by transitioning from an endogenous reference system to an exogenous reference system, thereby solving the detection limitation in cell-free samples.
2Productivity
If a small number of miRNAs are measured using DNA microarrays, then the assay can be performed, but current correction methods lack accuracy due to the difficulty in detecting stable endogenous miRNAs in body fluids
Solution Approach 1:
Artificial RNA molecules serve as intermediary normalization controls that can be reliably detected even when measuring small numbers of miRNAs. These intermediaries provide a stable reference signal that enables accurate correction of expression levels regardless of the number of target miRNAs being measured, solving the accuracy problem in low-throughput scenarios.
Solution Approach 2:
The artificial RNA molecules are designed to be self-contained normalization standards that carry their own detection signals. They autonomously provide the reference information needed for correction without requiring separate experiments or additional sample processing, enabling accurate normalization to be performed as part of the same assay as the target miRNA measurement.
3Ease of operation
If traditional normalization methods using housekeeping RNAs or mRNAs are applied to body fluid samples, then the existing protocols can be used, but the methods fail to provide accurate normalization due to the absence of stable endogenous controls in cell-free samples
Solution Approach 1:
The artificial RNA molecules function as intermediary normalization standards that can be integrated into existing DNA microarray workflows. By adding these exogenous controls to the hybridization mixture, the patent maintains the simplicity of traditional protocols while dramatically improving measurement accuracy through reliable reference signals that are specifically designed for detection in body fluid samples.
Solution Approach 2:
The artificial RNA normalization controls are designed to be universally applicable across different body fluid samples and experimental conditions. They can be used in the same DNA microarray assays as target miRNAs, serving multiple functions including normalization, quality control, and experimental validation, thereby maintaining operational simplicity while enhancing accuracy.
Data Source
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AI summary
Disclosed is a method for comparative analysis of the expression levels of target miRNAs among a plurality of body fluid samples. In the method for comparative analysis of the present invention, the expression levels of the target miRNAs in each body fluid sample are corrected using the expression level(s) of a correcting endogenous miRNA(s) that is/are simultaneously measured with the expression levels of the target miRNAs in the sample. As the correcting endogenous miRNA(s), one or more miRNAs selected from specific 10 kinds of correcting endogenous miRNAs is/are used. By the present invention, comparative analysis of target miRNAs among body fluid samples can be carried out more accurately than by conventional techniques.