Molecular characterization of lipoprotein lipase, hepatic lipase and pancreatic lipase genes: Effects of fasting and refeeding on their gene expression in red sea bream Pagrus major

Abstract

To investigate the nutritional regulation of lipid metabolism in fish, molecular characterization of lipases was conducted in red sea bream Pagrus major, and the effects of fasting and refeeding on their gene expression was examined. Together with data from a previous study, a total of four lipase genes were identified and characterized as lipoprotein lipase (LPL), hepatic lipase (HL) and pancreatic lipase (PL). These four lipase genes, termed LPL1, LPL2, HL and PL, share a high degree of similarity. LPL1 and LPL2 genes were expressed in various tissues including adipose tissue, gill, heart and hepatopancreas. HL gene was exclusively expressed in hepatopancreas. PL gene expression was detected in hepatopancreas and adipose tissue. Red sea bream LPL1 and LPL2 gene expression levels in hepatopancreas were increased during 48 h of fasting and decreased after refeeding, whereas no significant change in the expression levels of LPL1 and LPL2 was observed in adipose tissue, indicating that LPL1 and LPL2 gene expression is regulated in a tissue-specific manner in response to the nutritional state of fish. HL and PL gene expression was not affected by fasting and refeeding. The results of this study suggested that LPL, HL and PL gene expression is under different regulatory mechanisms in red sea bream with respect to the tissue-specificities and their nutritional regulation.

Feed restriction and genetic selection on the expression and activity of metabolism regulatory enzymes in rabbits

“…HL did not suffer any influence of food restriction on its mRNA level in this experimental breed, which agrees with Oku et al (2006) who worked with fasted fish that showed no influence of fasting on the expression of HL in the hepatopancreas. Even though HL did not present any change in this breed, triacylglycerol level did decrease in the plasma of the restricted NZ animals over controls.…”

Towards Fish Lipid Nutrigenomics: Current State and Prospects for Fin-Fish Aquaculture

“…LPL1 and LPL2 genes are ubiquitously expressed but HL is exclusively expressed in hepatic tissue and PL in hepatopancreas and adipose tissue. The ubiquitous LPL1 and LPL2 genes are regulated in a tissue-specific manner in response to the nutritional state of fish (Oku et al 2006), and recently some knowledge on how nutritional and seasonal status and hormones affect these genes have been obtained in several fish. Starvation increases, and dietary fatty acids differentially regulate LPL expression in red sea bream liver and adipose tissue Oku et al 2006).…”

“…The ubiquitous LPL1 and LPL2 genes are regulated in a tissue-specific manner in response to the nutritional state of fish (Oku et al 2006), and recently some knowledge on how nutritional and seasonal status and hormones affect these genes have been obtained in several fish. Starvation increases, and dietary fatty acids differentially regulate LPL expression in red sea bream liver and adipose tissue Oku et al 2006). In rainbow trout adipose LPL activity is regulated by insulin with tissue-specific modulation following food intake (Albalat et al 2006).…”

“…Insulin may also modulate gene transcription as in Atlantic salmon hepatocytes where it upregulates mRNA levels of scavenger receptor class B, type I, which is important in mammalian lipid homeostasis (Kleveland et al 2006b). Further, in red sea bream, the LPL gene contains a sequence homologous to the mammalian insulin responsive element ) and insulin appears to induce adipocyte differentiation and increase differentiation-linked expression of the LPL gene in red sea bream (Oku et al 2006). Nutritional status may influence the biological activity of insulin and hence link lipid nutrition to metabolism in rainbow trout, as plasma insulin levels decrease during fasting and postprandially along with a decreased number of insulin receptors in adipose tissue (Planas et al 2000).…”

Effects of dietary lipid levels on growth, survival and lipid metabolism during early ontogeny of Pelteobagrus vachelli larvae

“…PL is synthesized by pancreatic acinar cells, where it is secreted into the intestinal lumen and aids in the intestinal hydrolysis of long-chain triglyceride fatty acids (Verger, 1984). Recently, the LPL cDNA has been cloned in several fish species including zebrafish (Danio rerio) (Arnault et al, 1996), rainbow trout (Oncorhynchus mykiss) (Lindberg and Olivecrona, 2002), gilthead sea bream (Sparus aurata) (Saera-Vila et al, 2005) and red sea bream (Pagrus major) (Oku et al, 2006). The nutritional regulation of LPL has been studied in several species.…”