MiR-122, miR-133a, and miR-206 as potential biomarkers for post-mortem interval estimation

Area of Science:

• Forensic Science
• Molecular Biology
• Genomics

Background:

• Accurate post-mortem interval (PMI) estimation is critical in forensic investigations.
• MicroRNAs (miRNAs) are stable non-coding RNAs within the cell nucleus, offering potential for PMI determination.
• This study investigates specific miRNAs as biomarkers for PMI estimation.

Purpose of the Study:

• To assess the utility of miR-122, miR-133a, and miR-206 as biomarkers for estimating the post-mortem interval (PMI).
• To analyze miRNA expression patterns in various tissues at different time points and temperatures.
• To identify the most stable endogenous control for miRNA expression analysis in forensic contexts.

Main Methods:

• Evaluated the stability of reference genes RNU6B and 5 srRNA using Delta Ct, Best Keeper, and Genorm to select the optimal control.
• Quantified the expression levels of miR-122, miR-133a, and miR-206 in heart, skeletal muscle, liver, and brain tissues of mice over a 10-day period.
• Exposed mice to controlled temperatures (4℃ and 21℃) to simulate different post-mortem conditions.

Main Results:

• RNU6B was identified as the most stable reference gene for miRNA expression analysis.
• miR-122 levels significantly decreased in most tissues by days 8-10, particularly at 4℃.
• miR-133a showed a consistent decrease over time in the heart, muscles, and brain, with notable declines by days 8-10.
• miR-206 expression varied, decreasing in muscles and liver at 4℃ but increasing in the brain at 21℃.

Conclusions:

• miR-122 and miR-133a are promising biomarkers for PMI estimation, especially in heart and skeletal muscle tissues.
• The expression patterns of these miRNAs are influenced by time post-mortem and ambient temperature.
• Further research can refine the use of these miRNAs for more accurate PMI determination in forensic casework.