Systematic assessment for potential endogenous normalizers for microRNA analysis in fecal samples

Area of Science:

• Biochemistry
• Molecular Biology
• Genomics

Background:

• MicroRNAs (miRNAs) show potential as biomarkers for various diseases in fecal samples.
• Current fecal miRNA analysis lacks standardized normalization methods, hindering reliable biomarker discovery.
• Existing normalization strategies are insufficient for the complexities of fecal sample analysis.

Purpose of the Study:

• To identify and validate a stable endogenous normalizer for microRNA (miRNA) analysis in human fecal samples.
• To address the lack of consensus on normalization techniques for fecal miRNA biomarker studies.
• To find a reliable miRNA that is unaffected by sample collection or processing variables.

Main Methods:

• Multi-step study involving three independent cohorts of healthy subjects and patients with inflammatory bowel disease (IBD) and liver disease.
• MiRNA profiling using serial dilutions of blood and fecal samples.
• Analysis via Affymetrix GeneChip microarray technology and validation with TaqMan quantitative real-time PCR (qPCR).

Main Results:

• Five stable miRNAs were identified in fecal samples; miR-638 demonstrated exceptional stability (Log2FC of 0.0004).
• miR-638 stability was confirmed across independent cohorts of IBD and liver disease patients.
• No significant influence of age or other factors on fecal miR-638 levels was observed.

Conclusions:

• miR-638 is a highly stable and suitable endogenous normalizer for fecal miRNA analysis.
• Its stability and high concentration in feces offer advantages over previously used normalizers like miR-16.
• This finding supports the development of more accurate miRNA-based diagnostic tools for gastrointestinal and liver diseases.