# Plasma miRNAome Profiling Reveals Candidate Biomarkers for Low- and High-Dose Whole-Body Ionizing Radiation Exposure

## TL;DR

This study identifies specific microRNAs in mouse plasma that change after low or high radiation exposure, suggesting they could be used as biomarkers to assess radiation dose.

## Contribution

The study introduces a novel pipeline for plasma miRNA profiling and identifies dose-specific miRNA biomarkers for radiation exposure.

## Key findings

- High-dose radiation exposure upregulated 14 and downregulated 5 miRNAs in mouse plasma.
- Seven miRNAs were significantly induced at low-dose radiation, including miR-126a-5p and miR-133a-3p.
- Five miRNAs were shared between low- and high-dose responses, indicating dose-independent effects.

## Abstract

MicroRNAs (miRNAs) are small, non-coding RNA molecules that regulate gene expression and remain stable in biological fluids, even under harsh conditions. Their stability and responsiveness to environmental stressors make them strong candidates for radiation biodosimetry. This study aimed to (1) establish a robust in vivo pipeline for miRNAome profiling and (2) identify plasma-based miRNA biomarkers of ionizing radiation at low and high doses.

BALB/c mice were exposed to sham, 100 mGy, or 2 Gy of X-rays. Plasma was collected 6 h post-irradiation. Total RNA was extracted, and next-generation sequencing was used to profile the plasma miRNAome. Differentially expressed miRNAs were identified relative to sham controls, and selected candidates were validated using RT-qPCR.

A total of 630 unique miRNAs were detected. High-dose exposure (2 Gy) significantly upregulated 14 and downregulated 5 miRNAs. Seven miRNAs were significantly induced at 100 mGy, including miR-126a-5p and miR-133a-3p, which were exclusive to low-dose exposure. Five miRNAs were shared between both doses, indicating dose-independent responses. RT-qPCR confirmed expression trends.

This study identified distinct and shared circulating miRNA signatures for low- and high-dose radiation exposure. These findings support the potential of miRNAs as minimally invasive, dose-stratified biomarkers for radiation biodosimetry.