Low-Dose Ionizing Radiation Modulates Translation Efficiency in Human Lung Fibroblasts

Area of Science:

• Molecular Biology
• Radiation Biology
• Cellular Response to Radiation

Background:

• Cellular responses to low-dose ionizing radiation (≤ 0.1 Gy) are crucial for radiation protection policies.
• High-dose radiation impacts gene expression and protein synthesis, but low-dose effects are less understood.
• Transcriptome analysis may not fully capture early cellular responses to radiation.

Purpose of the Study:

• To investigate the cellular impact of low-dose ionizing radiation exposure.
• To determine if translation or transcription is a more sensitive indicator of early low-dose radiation effects.
• To identify specific molecular targets affected by low-dose gamma radiation.

Main Methods:

• Ribosome profiling was employed on normal human lung fibroblast cells.
• Cells were exposed to low (0.1 Gy) and high (1 Gy) doses of 60Cobalt gamma (γ) rays.
• Analysis was conducted at 1 and 6 hours postirradiation.

Main Results:

• Global protein synthesis remained unchanged at low doses (0.1 Gy) at 1 and 6 hours postirradiation.
• Specific messenger RNAs (mRNAs) exhibited altered translation efficiency, indicating translational shifts.
• The small GTP-binding protein RAB33B was identified as a translationally upregulated target.

Conclusions:

• Translation efficiency serves as a more sensitive readout of early low-dose gamma radiation effects compared to transcriptional changes.
• Conventional transcriptome analyses may not fully capture the dynamic gene expression changes induced by low-dose radiation.
• Selective mRNA translation plays a role in the distinct cellular response to low-dose irradiation.