The expression of p53-regulated genes in human cultured lymphoblastoid TSCE5 and WTK1 cell lines during spaceflight

Abstract

Purpose: The space environment contains two major biologically significant influences; space radiations and microgravity. The 53 kDa tumour suppressor protein (p53) plays a role as a guardian of the genome through the activity of p53-centered signal transduction pathways. The aim of this study was to clarify the biological effects of space radiations, microgravity, and the space environment on the gene expression of p53-regulated genes.

Materials and methods: Space experiments were performed with two human cultured lymphoblastoid cell lines; one line (TSCE5) bears a wild-type p53 gene status, and another line (WTK1) bears a mutated p53 gene status. Under one gravity or microgravity conditions, the cells were grown in the cell biology experimental facility (CBEF) of the International Space Station for 8 days without experiencing stress during launching and landing because the cells were frozen during these periods. Ground control samples also were cultured for 8 days in the CBEF on the ground during the spaceflight. Gene expression was analysed using an Agilent Technologies 44 k whole human genome microarray DNA chip.

Results: p53-dependent up-regulated gene expression was observed for 111, 95, and 328 genes and p53-dependent down-regulated gene expression was found for 177, 16, and 282 genes after exposure to space radiations, to microgravity, and to both, respectively.

Conclusions: The data provide the p53-dependent regulated genes by exposure to radiations and/or microgravity during spaceflight. Our expression data revealed genes that might help to advance the basic space radiation biology.

Keywords:

• space radiations
• microgravity
• p53
• gene expression
• spaceflight

Acknowledgements

This study was performed as a JAXA and National Aeronautics and Space Administration (NASA) space experiment. This study was supported by a grant for a Ground-based Research Program for Space Utilization from the Japan Space Forum. This work was also supported, in part, by a grant from the Central Research Institute of the Electric Power Industry in Japan, and by grants from the Ministry of Education, Science, Sports, Culture and Technology of Japan (21310040).

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.