Synergistic effects of hypergravity and immune challenge on the zebrafish larval transcriptome

The transcriptomic interaction between altered gravity and innate immunity remains largely unexplored. In this study, we established a novel dual-stress model combining 3g hypergravity with lipopolysaccharide (LPS) immune challenge in 5 days post-fertilization (dpf) zebrafish (Danio rerio) larvae. RNA sequencing revealed that exposure to hypergravity alone induced no differentially expressed genes (DEGs), indicating a remarkable transcriptional resilience. In contrast, the addition of an immune challenge under hypergravity conditions triggered a substantial transcriptomic response involving 2,706 DEGs. Functional enrichment analyses identified significant alterations in pathways related to immune function, development, and circadian regulation. Targeted qPCR analyses further validated the expression patterns of selected genes. These findings suggest that while zebrafish larvae can effectively tolerate hypergravity alone, the combination of gravitational and immune stressors elicits profound molecular responses. This study provides new insights into the interplay between altered gravity and innate immunity using an animal model, contributing to future strategies aimed at safeguarding astronaut health and supporting space-based aquaculture systems.