Characterization, tissue distribution of resistin gene and the effect of fasting and refeeding on resistinmRNA expression in Siberian sturgeon (Acipenser baerii)

Abstract

Resistin as an adipokine identified from rodents in 2001 is involved in many biological processes. However, little is known about this gene in fish. We cloned Siberian sturgeon (Acipenser baerii) resistin cDNA of 795 base pairs, encoding 107 amino acids, which showed 38-40% identity to human and rodents. Real-time quantitative PCR showed that the resistin gene was widely distributed in tissues of Siberian sturgeon, with the highest expression in liver. After fasting for 1, 3, 6 and 10 days, the expression of the resistin gene in the liver of Siberian sturgeon decreased significantly, and after refeeding on the 10 days of fasting the resistin mRNA expression increased rapidly, suggesting that resistin may play an important role in liver in response to starvation. Taken together, these results suggest that resistin may be involved in the regulation of energy homeostasis in liver.

Recent advances in the crosstalk between adipose, muscle and bone tissues in fish

“…Besides adipose tissue, the liver is an important organ of lipid accumulation in some species, and it is essential in metabolic homeostasis, suggesting that resistin, as other classical adipokines, may have a role in metabolism regulation. In fact, in Siberian sturgeon, resistin mRNA expression in the liver decreased after fasting and increased sharply after refeeding, confirming it is affected by nutritional status ( 12 ) supporting this hypothesis. Nonetheless, data is limited to this study; consequently, further studies are needed to investigate the role of resistin as a hormone involved in tissue crosstalk in fish.…”

“…In fact, peripheral blood mononuclear cells, macrophages, and bone marrow cells are the primary source of circulating human resistin ( 108 ). Resistin is widely found in other species and, for example, it is highly expressed in the lung in porcine, goat and yak ( 12 ).…”

“…Genes encoding resistin-like peptides were found in Actinistia (coelacanth, a lobe-finned fish), but not in fish from the Actinopterygii, Chondrichthyes, or Agnatha. More recently, a resistin full-length cDNA has been obtained, with an open reading frame encoding 106 amino acids in Siberian sturgeon ( Acipenser baerii ) ( 12 ), showing low identity with other vertebrates, except when compared with the sterlet ( Acipenser ruthenus ). However, the resistin C-terminal is well conserved among species, suggesting that this region may be important to its physiological roles.…”

“…Moreover, in mammals it is proved that TNFα induces insulin-resistance ( 12 , 150 ), by impairing insulin-stimulated glucose uptake through the inhibition of insulin signaling at the insulin receptor substrate level ( 151 , 152 ), but on the other hand, TNFα increases basal glucose uptake in adipose tissue ( 153 ). From studies in rainbow trout adipocytes, it was concluded that stimulation of basal glucose uptake by TNFα seems to be conserved from fish to mammals.…”

“…Concerning adipogenesis, a negative effect of TNFα has been well documented in several in vitro models ( 12 , 154 , 155 ), including fish pre-adipocytes and adipocytes ( 6 , 15 ). In mammals, TNFα is both an inhibitor of adipocyte differentiation and a suppressor of some early stage genes responsible of pre-adipocyte conversion ( 156 ); although in rats or mice, low concentrations of TNFα have a promoting effect on adipocyte proliferation ( 155 , 157 ).…”