Transcriptomic analysis of embryonic mouse hypothalamic N38 cells exposed to high-energy protons and/or simulated microgravity

Purpose: Space exploration poses unique challenges to astronauts, especially the effects of space radiation and microgravity (μG). Understanding molecular responses to these factors is crucial for ensuring astronaut health, and this study aimed to identify transcriptomic changes in mouse hypothalamic cell line N38 (mHypoE-N38) caused by simulated space environments. Method: Four experimental groups were established, namely, a ground condition group (GC; the control group), a proton irradiated group (the space radiation group), a simulated μG group, and a proton irradiated × simulated μG group (the combination group). RNA sequencing and quantitative real-time polymerase chain reaction were performed to investigate key altered genes and to validate them. Results: Three hundred and fifty-five differentially expressed genes were identified. Notably, the expressions of UCN2 and UGT1A5 genes were upregulated in all three experimental groups, suggesting a shared regulatory mechanism with potential consequences for brain function during space missions. Moreover, the study revealed significant alterations in genes belonging to the USP17 and ZSCAN4 families, indicating active response to DNA damage and telomere maintenance. PCR results validated that UGT1A5, USP17 family, and ZSCAN4 families (ZSCAN4C, ZSCAN4D, and ZSCAN4F) were significantly upregulated at the mRNA level in the combination group, while UCN2, ZSCAN4A, and ZSCAN4B were not reproduced. Conclusion: The present study on mHypoE-N38 cells exposed to space environments revealed a complex molecular narrative with disease-oriented implications. The knowledge gained might serve as a cornerstone for developing strategies to mitigate potential health risks associated with extended exposure to space-related stressors.