Ionizing radiation-induced oxidative stress alters miRNA expression

Area of Science:

• Molecular Biology
• Cellular Stress Response
• Non-coding RNA Biology

Background:

• MicroRNAs (miRNAs) are small, non-coding RNAs regulating cellular processes.
• miRNA expression can change following exposure to stress-inducing anticancer agents like radiation, etoposide, and hydrogen peroxide (H2O2).

Purpose of the Study:

• To investigate the miRNA expression signature in response to genotoxic stress.
• To determine if reactive oxygen species (ROS) mediate the miRNA response to radiation.

Main Methods:

• Normal human fibroblasts were treated with radiation, H2O2, or etoposide.
• miRNA expression was analyzed using microarrays and RT-PCR.
• Reactive oxygen species (ROS) production was measured, and the effect of cysteine pre-treatment was assessed.

Main Results:

• Significant changes in miRNA expression were observed for 17, 23, and 45 miRNA species after radiation, H2O2, and etoposide treatments, respectively.
• A common miRNA expression signature was identified across different genotoxic agents.
• Radiation dose and time influenced miRNA expression changes, and cysteine pre-treatment reduced ROS production and miRNA alterations.

Conclusions:

• A shared miRNA expression signature exists in response to exogenous genotoxic agents.
• miRNAs are responsive to oxidative stress, as demonstrated by cysteine's ability to prevent radiation-induced changes.
• miRNAs play a role in cellular defense mechanisms against exogenous stress and genotoxic oxidative stress.