Differential Gene Expression in Human Fibroblasts Simultaneously Exposed to Ionizing Radiation and Simulated...

Area of Science:

• Space biology
• Radiation biology
• Cellular biology

Background:

• Space missions expose astronauts to cosmic radiation and microgravity (μG), significant health risks.
• Understanding cellular responses to these combined stressors is crucial for astronaut safety.

Purpose of the Study:

• To investigate gene expression changes in human fibroblasts exposed to simulated microgravity and irradiation.
• To identify biological pathways affected by simultaneous exposure to radiation and microgravity.

Main Methods:

• Human fibroblast cells (1BR-hTERT) were cultured under 1G or simulated μG.
• Cells were irradiated with X-rays or Carbon-ions (C-ions) at different time points.
• RNA sequencing (RNA-seq) and over-representation analyses were used to identify differentially expressed genes (DEGs) and pathways.

Main Results:

• Simulated microgravity alone affected genes related to oxygen levels and muscle contraction.
• Irradiation under 1G or simulated μG activated DNA damage repair, p53 signaling, cell cycle arrest, and apoptosis pathways.
• Combined exposure to microgravity and irradiation attenuated the transcriptional response to radiation.

Conclusions:

• Microgravity may alter cellular responses to space radiation.
• The attenuated response to irradiation under simulated microgravity suggests a potential subtle risk for astronauts during space missions.