Insulin induces expression of the hepatic <i>vaspin</i> gene

Abstract

Visceral adipose tissue-derived serine protease inhibitor (vaspin), initially identified in the visceral adipose tissue, is an adipokine that improves endoplasmic reticulum stress in obesity or insulin sensitivity and glucose tolerance. However, the transcriptional regulation of the hepatic vaspin gene remains elusive. We have previously shown that CCAAT-enhancerbinding protein α, a transcription factor of the basic leucine zipper class, positively regulates the vaspin gene. The present study aimed to investigate the nutritional or hormonal regulators of vaspin expression in the liver. For the fasting and refeeding study, mice in the fasting group were subjected to fasting for 24 h and then sacrificed. Mice in the refeeding group were subjected to fasting for 24 h and then refed with a 50% (w/w) sucrose/MF diet for further 24 h and then sacrificed. For the streptozotocin (STZ) study, STZ (50 mg/kg) was intraperitoneally injected into C57BL/6JJc1 mice for 5 d. Hepatic vaspin was repressed due to fasting for 24 h and was induced upon refeeding with a high-sucrose diet. In studies on liver-specific C/ EBPα-deficient mice, C/EBPα was not involved in the induction of hepatic vaspin upon refeeding. In addition, the depletion of insulin by streptozotocin treatment markedly decreased hepatic vaspin expression. Finally, fasting-repressed vaspin expression in the liver was significantly increased by direct injection of insulin into fasting mice. In conclusion, our results suggest that insulin is a positive regulator of hepatic vaspin expression.

Regulation of hepatic oxidative stress by voltage‐gated proton channels (Hv1/VSOP) in Kupffer cells and its potential relationship with glucose metabolism

“…We observed that expression of diverse types of genes is altered by lacking Hvcn1 (Tables 1 and 2). It is interesting that we observed the drastic expression change of Hcn3 and Serpina12 that have close relationship with diabetes 25,26 . It is possible that this expression change was caused by the alteration of glucose level that is observed both in the previous and the present studies.…”

“…It is interesting that we observed the drastic expression change of Hcn3 and Serpina12 that have close relationship with diabetes. 25,26 It is possible that this expression change was caused by the alteration of glucose level that is observed both in the previous and the present studies. On the contrary, it appears that the influence of these genes on Hvcn1-deficient liver function is limited, because the basic expression level of these genes is quite low (Table 1), and therefore, their function has not been established in liver.…”

Association of adipocytokines with lipid and glycemic profiles in women with normal weight obesity

“…On the other hand, the result of an experimental study in mice reported that injection of insulin in fasting status increase the hepatic expression of vaspin [31]. Previous studies have indicated that serum concentration of vaspin was increased with worsening insulin resistance in children and impaired glucose tolerance and obesity in adults [32][33][34].…”

Association of Adipocytokines with Lipid and Glycemic Profiles in Women with Normal Weight Obesity

“…On the other hand, the results of experimental study in mice, reported that injection of insulin in fasting status increased positively the hepatic expression of vaspin [30].…”