Oleoylethanolamide enhances beta-adrenergic-mediated thermogenesis and white-to-brown adipocyte phenotype in epididymal white adipose tissue in rat
DISEASE MODELS & MECHANISMS
Authors: Suarez, Juan; Rivera, Patricia; Arrabal, Sergio; Crespillo, Ana; Serrano, Antonia; Baixeras, Elena; Pavon, Francisco J.; Cifuentes, Manuel; Nogueiras, Ruben; Ballesteros, Joan; Dieguez, Carlos; Rodriguez de Fonseca, Fernando
Abstract
beta-adrenergic receptor activation promotes brown adipose tissue (BAT) beta-oxidation and thermogenesis by burning fatty acids during uncoupling respiration. Oleoylethanolamide (OEA) can inhibit feeding and stimulate lipolysis by activating peroxisome proliferator-activating receptor-alpha (PPAR alpha) in white adipose tissue (WAT). Here we explore whether PPAR alpha activation potentiates the effect of beta 3-adrenergic stimulation on energy balance mediated by the respective agonists OEA and CL316243. The effect of this pharmacological association on feeding, thermogenesis, beta-oxidation, and lipid and cholesterol metabolism in epididymal (e) WAT was monitored. CL316243 (1 mg/kg) and OEA (5 mg/kg) co-administration over 6 days enhanced the reduction of both food intake and body weight gain, increased the energy expenditure and reduced the respiratory quotient (VCO2/VO2). This negative energy balance agreed with decreased fat mass and increased BAT weight and temperature, as well as with lowered plasma levels of triglycerides, cholesterol, nonessential fatty acids (NEFAs), and the adipokines leptin and TNF-alpha. Regarding eWAT, CL316243 and OEA treatment elevated levels of the thermogenic factors PPAR alpha and UCP1, reduced p38-MAPK phosphorylation, and promoted brown-like features in the white adipocytes: the mitochondrial (Cox4i1, Cox4i2) and BAT (Fgf21, Prdm16) genes were overexpressed in eWAT. The enhancement of the fatty-acid beta-oxidation factors Cpt1b and Acox1 in eWAT was accompanied by an upregulation of de novo lipogenesis and reduced expression of the unsaturated-fatty-acid-synthesis enzyme gene, Scd1. We propose that the combination of beta-adrenergic and PPAR alpha receptor agonists promotes therapeutic adipocyte remodelling in eWAT, and therefore has a potential clinical utility in the treatment of obesity.
The Features of Copper Metabolism in the Rat Liver during Development
PLOS ONE
Authors: Zatulovskaia, Yulia A.; Ilyechova, Ekaterina Y.; Puchkova, Ludmila V.
Abstract
Strong interest in copper homeostasis is due to the fact that copper is simultaneously a catalytic co-factor of the vital enzymes, a participant in signaling, and a toxic agent provoking oxidative stress. In mammals, during development copper metabolism is conformed to two types. In embryonic type copper metabolism (ETCM), newborns accumulate copper to high level in the liver because its excretion via bile is blocked; and serum copper concentration is low because ceruloplasmin (the main copper-containing protein of plasma) gene expression is repressed. In the late weaning, the ETCM switches to the adult type coppermetabolism (ATCM), which is manifested by the unlocking of copper excretion and the induction of ceruloplasmin gene activity. The considerable progress has been made in the understanding of the molecular basis of copper metabolic turnover in the ATCM, but many aspects of the copper homeostasis in the ETCM remain unclear. The aim of this study was to investigate the copper metabolism during transition from the ETCM (up to 12-days-old) to the ATCM in the rats. It was shown that in the liver, copper was accumulated in the nuclei during the first 5 days of life, and then it was re-located to the mitochondria. In parallel with the mitochondria, copper bulk bound with cytosolic metallothionein was increased. All compartments of the liver cells rapidly lost most of their copper on the 13th day of life. In newborns, serum copper concentration was low, and its major fraction was associated with holo-Cp, however, a small portion of copper was bound to extracellular metallothionein and a substance that was slowly eluted during gel-filtration. In adults, serum copper concentration increased by about a factor of 3, while metallothionein-bound copper level decreased by a factor of 2. During development, the expression level of Cp, Sod1, Cox4i1, Atp7b, Ctr1, Ctr2, Cox17, and Ccs genes was significantly increased, and metallothionein was decreased. Atp7a gene's activity was fully repressed. The copper routes in newborns are discussed.