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

Area of Science:

• Cellular Biology
• Radiation Biology
• Molecular Biology

Background:

• Understanding cellular responses to low-dose ionizing radiation (≤ 0.1 Gy) is critical for radiation protection.
• High-dose radiation impacts gene expression and protein synthesis, but low-dose effects are less understood.

Purpose of the Study:

• To investigate the cellular impact of low-dose ionizing radiation exposure.
• To determine if low-dose radiation affects protein synthesis and gene expression.
• To identify specific molecular targets responding to low-dose radiation.

Main Methods:

• Ribosome profiling was employed on 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 changes at the translational level.
• Transcriptional changes were minimal, highlighting translation as a more sensitive readout of early low-dose γ-radiation effects.
• The small GTP-binding protein RAB33B was identified as a translationally upregulated target.

Conclusions:

• Low-dose ionizing radiation primarily affects cellular responses through selective mRNA translation, not global protein synthesis.
• Conventional transcriptome analyses may not fully capture the dynamic gene expression changes induced by low-dose radiation.
• Selective translation plays a significant role in the distinct cellular response to low-dose irradiation.