SRA

The neuroendocrine regulation of seasonal energy homeostasis and rheostasis are widely studied. However, the molecular pathways underlying tissue-specific adaptations remain poorly described. We conducted an experiment to examine long-term rheostatic changes in energy stability using the well-characterized photoperiodic response of the Japanese quail. We exposed quails to photoperiodic transitions simulating the annual photic cycle and examined the morphology and fat deposition in liver, and white adipose tissue. To identify molecular substrates during the vernal transition in lipid accumulation, we conducted transcriptomic analyses of white adipose and liver tissues. We identified transcripts involved in adipocyte growth (Cysteine Rich Angiogenic Inducer 61, Very Low Density Lipoprotein Receptor) and obesity-linked disease resistance (Insulin-Like Growth Factor Binding Protein 2, Apolipoprotein D) increase expression in anticipation of body mass gain. In the liver, under long photoperiods, transcripts involved in fatty acid (FA) synthesis (Fatty Acid Synthase, Fatty Acid Desaturase 2) were down-regulated. Parallel upregulation of hepatic Fatty Acid Translocase and Pyruvate Dehydrogenase Kinase 4 expression suggests increased circulatory FA uptake and a switch from glucose to FA utilization. Overall, we have identified tissue-specific biochemical and molecular changes that drive photoperiod-induced adipogenesis in quails. These findings can be use to determine conserved pathways that enable animals to accumulate fat without developing metabolic diseases. Overall design: To investigate seasonal changes in liver and white adipose tissue transcriptome, male quails (N=12 samples) housed in the long photoperiod (16L:8D) were subjected to 8 hours short photoperiod (N=4, 8L), 12 hours long photoperiod (N=4,12v) and 16 hours long photoperiod (N=4, 16v). Birds were killed by cervical dislocation followed by exsanguination via severing the jugular vein. The liver, and abdominal white adipose tissue were rapidly collected and stored at -80°C. We then performed RNA sequencing of RNA extracted (RNEasy plus mini kit) from the liver (N=12) and adipose tissue (N=12) using GridION Mk1 (Oxford Nanopore Technologies).