Adropin induction of lipoprotein lipase expression in tilapia hepatocytes

Abstract

The peptide hormone adropin plays a role in energy homeostasis. However, biological actions of adropin in non-mammalian species are still lacking. Using tilapia as a model, we examined the role of adropin in lipoprotein lipase (LPL) regulation in hepatocytes. To this end, the structural identity of tilapia adropin was established by 5 0 /3 0 -rapid amplification of cDNA ends (RACE). The transcripts of tilapia adropin were ubiquitously expressed in various tissues with the highest levels in the liver and hypothalamus. The prolonged fasting could elevate tilapia hepatic adropin gene expression, whereas no effect of fasting was observed on hypothalamic adropin gene levels. In primary cultures of tilapia hepatocytes, synthetic adropin was effective in stimulating LPL release, cellular LPL content, and total LPL production. The increase in LPL production also occurred with parallel rises in LPL gene levels. In parallel experiments, adropin could elevate cAMP production and up-regulate protein kinase A (PKA) and PKC activities. Using a pharmacological approach, cAMP/PKA and PLC/inositol trisphosphate (IP3)/PKC cascades were shown to be involved in adropin-stimulated LPL gene expression. Parallel inhibition of p38MAPK and Erk1/2, however, were not effective in these regards. Our findings provide, for the first time, evidence that adropin could stimulate LPL gene expression via direct actions in tilapia hepatocytes through the activation of multiple signaling mechanisms.

Bile acids are important direct and indirect regulators of the secretion of appetite- and metabolism-regulating hormones from the gut and pancreas

“…For all measurements, standard curves were prepared in perfusion buffer, which was shown to be devoid of matrix effects in control studies. Further assay details on the respective assays, including experimental detection limits, can be found elsewhere [25] .…”

Adropin as a potential mediator of the metabolic system‐autonomic nervous system‐chronobiology axis: Implementing a personalized signature‐based platform for chronotherapy

“…The proposed mechanism includes regulation of hepatic lipogenic genes and adipose tissue peroxisome proliferator‐activated receptor gamma (PPAR‐γ) 11 . Adropin stimulated lipoprotein lipase (LPL) secretion in primary cultures of tilapia hepatocytes by inducing the production of cyclic adenosine monophosphate (cAMP) and upregulation of protein kinase A (PKA) and protein kinase C (PKC) activities 12 …”

“…11 Adropin stimulated lipoprotein lipase (LPL) secretion in primary cultures of tilapia hepatocytes by inducing the production of cyclic adenosine monophosphate (cAMP) and upregulation of protein kinase A (PKA) and protein kinase C (PKC) activities. 12 Adropin improves the regulation of glucose metabolism in obesity, exerting a protective effect against hyperinsulinemia and liver steatosis. 11 Administration of adropin to diet-induced obese (DIO) mice augmented glucose tolerance, ameliorated insulin resistance and shifted the fuel selection to the use of carbohydrate over fat in skeletal muscle.…”

Adropin expression correlates with age-related neuropathologies in the human brain and improves neuroinflammation and cognitive function in aging mice

“…Adropin regulates peripheral carbohydrate and lipid metabolism 17,20,21,23,25,26,[30][31][32][33][34][35][36][37] and vascular function 24,[38][39][40] . Expression of the ENHO transcript is however several orders of magnitude higher in the brain relative to non-neural tissues 17,34,[41][42][43][44] .…”