| dc.description.abstract | Metabolism involves a network of interconnected reactions, of which pathways are responsible for growth, renewal, and cellular maintenance. Environmental stress can pose challenges for the proper functioning of these pathways. This project integrates physiological and bioinformatics approaches to study how metabolic pathways are adjusted under stress in zebrafish (Danio rerio). Metabolic stress in zebrafish was induced by exposing embryo-larval life-stages of fish to 1 uM of the tricarboxylic acid (TCA) cycle inhibitor, CPI-613, for 20 days. Physiological effects on whole-fish were determined using respirometry to measure oxygen consumption rate (as a proxy for metabolic rate). The oxygen consumption rate of fish was measured on Days 5, 10, 15, and 20 of exposure. The analysis of the effects of exposure to CPI-613 on metabolic rate showed significant decrease in oxygen consumption after 5 days of exposure, followed by a gradual recovery of oxygen consumption rates by Day 20 of exposure (i.e. equivalent to the solvent control group of 0.01% DMSO). In addition, whole-genome transcriptomics, or RNA-sequencing (RNA-seq), analysis was also performed on embryo-larval zebrafish sub-sampled on Day 5 and 20 of exposure. The comparison of gene expressions for selected genes for Day 5 vs. Day 20 of exposure showed no effects on the expression of genes belonging to the pyruvate dehydrogenase complex (PDHC). However, in contrast to the genes of the PDH enzyme complex, a statistically significant increase in expression of hypoxia inducible factor (HIF-1) genes was observed at Day 5 relative to Day 20. The increase in HIF-1 expression indicates an adaptive response whereby zebrafish are inducing the expression of a transcription factor that helps an organism to adapt to metabolic stress (such as low oxygen or TCA cycle disruption). Taken together, the results of this project show an adaptive metabolic response that manifests both at the transcriptome level (i.e. upregulation of gene expression), and physiological level (increase in respiration rate). | |
