Description
Low incubation temperature during early development negatively affects survival and related innate immune processes in zebrafish larvae exposed to lipopolysaccharide Overall design: Zebrafish embryos were collected from 28 °C, and divided into three temperature groups (24 °C, 28 °C, 32 °C) for incubation. At the first-feeding stage, larvae from each incubation temperature group were further split into three temperature groups in a full-factorial way for LPS challenge. In total, nine temperature groups (three incubation temperatures x three challenge temperatures) were generated. At 24 h post LPS challenge, mortality of larvae were recorded. Larvae originating from 24 °C incubation temperature group had higher mortality rate than larvae from the other two temperature groups. LPS-treated larvae from three temperature groups, incubation 24 °C x challenge 24 °C, incubation 24 °C x challenge 32 °C, and incubation 32 °C x challenge 24 °C, together with their respective control were chosen for transcriptomic analyses using mRNA sequencing. A total of 722 genes were determined differentially expressed (DEGs) by DESeq2 (adjusted p-value < 0.05) in LPS-challenged larvae compared to control, and 605 of them had a fold change greater than 1.5, including 294 DEGs (144 up-/150 down-regulated) in larvae incubated and challenged with LPS at 24 °C; 33 DEGs (20 up-/13 down-regulated) in larvae incubated at 32 °C and challenged at 24 °C; and 278 DEGs (190 up-/88 down-regulated) in larvae incubated at 24 °C and challenged at 32 °C. Larvae incubated and challenged with LPS at 24 °C had stimulated innate immune response compared to control, while they also showed down-regulated innate immune processes and genes. In larvae incubated at 32 °C and challenged at 24 °C, the innate immune processes were up-regulated in larvae exposed to LPS compared to control, and theses processes were even much stronger (with higher enrichment values) than larvae from incubation and challenge temperature of 24 °C. In larvae incubated at 24 °C and challenged with LPS at 32 °C, limited innate immune response were up-regulated, and additional hypoxia and oxidative processes were observed. Genes annexin A2a, S100 calcium binding protein A10b, and lymphocyte antigen-6, epidermis were identified as promising candidates for LPS recognition and signal transduction.