Transcriptome profiles of zebrafish larvae from a caffeine-induced anxiety model and a high fat-diet induced obesity model [miRNA-Seq]

Obesity associates with anxiety disorders in adult humans, rodents and fish, although there is also evidence to the contrary. Moreover, it is unknown if this association is developmentally regulated, and which genes are involved. RNA-sequencing differences between caffeine-induced anxious zebrafish larvae, which exhibited greater thigmotaxis, erratic swimming and higher whole-body cortisol levels than matched controls, and high fat diet-fed obese larvae with more numerous and larger peritoneal adipocytes than standard diet controls, were revealed. There were 231 poly(A)+ genes common to both models (padj<0.05) and 75% of the transcripts upregulated (>1.5 fold) in the anxiety model were downregulated (<0.67 fold) in obese larvae. Immune system pathways were overrepresented among these inversely regulated genes. Overall design: Profile analyses of RNA-seq poly(A)+ and miRNA data were carried out on two zebrafish larval models (15 days post fertilization[dpf]), one of anxiety (induced by a half hour exposure to 100 mg/liter caffeine [CAF], compared to no treatment [NO]) and the other of obesity (induced by feeding 6 dpf larvae a high fat diet [HFD, egg yolk-based] until 15 dpf, compared to a standard diet [SD]). Both models were optimized and validated, the anxiety model by behavioral and cortisol level tests and the obesity model by histology-based adiposity analysis. RNA was extracted from pools of 30 larvae per replicate (3 replicates per treatment [NO, CAF, SD, HFD]), euthanized by ice-cold water and snap-frozen in liquid nitrogen.