Goose Hepatic IGFBP2 Is Regulated by Nutritional Status and Participates in Energy Metabolism Mainly through the Cytokine-Cytokine Receptor Pathway.

Changes in the nutritional status of animals significantly affect their health and production performance. However, it is unclear whether insulin-like growth factor-binding protein 2 (IGFBP2) mediates these effects. This study aimed to investigate the impact of changes in nutritional and energy statuses on hepatic IGFBP2 expression and the mechanism through which IGFBP2 plays a mediating role. Therefore, the expression of was first determined in the livers of fasting/refeeding and overfeeding geese. The data showed that overfeeding inhibited expression in the liver compared with the control (normal feeding) group, whereas the expression of in the liver was induced by fasting. Interestingly, the data indicated that insulin inhibited the expression of in goose primary hepatocytes, suggesting that the changes in expression in the liver in the abovementioned models may be partially attributed to the blood insulin levels. Furthermore, transcriptome sequencing analysis showed that the overexpression of in geese primary hepatocytes significantly altered the expression of 337 genes (including 111 up-regulated and 226 down-regulated genes), and these differentially expressed genes were mainly enriched in cytokine-cytokine receptor, immune, and lipid metabolism-related pathways. We selected the most significant pathway, the cytokine-cytokine receptor pathway, and found that the relationship between the expression of these genes and in goose liver was in line with the findings from the overexpression assay, i.e., the decreased expression of was accompanied by the increased expression of , , , , and in the overfed versus normally fed geese, and the increased expression of was accompanied by the decreased expression of these genes in fasting versus normally fed geese, and refeeding prevented or attenuated the effects of fasting. The association between the expression of these genes and was verified by -siRNA treatment of goose primary hepatocytes, in which IGFBP2 expression was induced by low serum concentrations. In conclusion, this study suggests that IGFBP2 mediates the biological effects induced by changes in nutritional or energy levels, mainly through the cytokine-cytokine receptor pathway.