Search

Objective: Elevation of energy expenditure through an increase of brown adipose tissue (BAT) thermogenesis is regarded as one of the most promising ways to prevent obesity development. The preoptic area (POA) of the hypothalamus is a critical area for control of BAT thermogenesis. However, the intracellular signaling cascades in the POA for regulation of BAT thermogenesis are poorly understood.Methods: Phosphorylation proteomics (phosphoproteomics) and bioinformatics approaches were used to disclose numerous hypothalamic signaling pathways involved in the regulation of BAT thermogenesis. Conditional manipulation of the p38α gene in mouse POA was performed by stereotaxic injection of adeno-associated virus 9 vector to explore the role of p38α in BAT thermogenesis.Results: Multiple hypothalamic signaling pathways were triggered by cold exposure, especially the mitogen-activated protein kinase (MAPK) signaling pathway. The p38α activation, but not extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun NH2-terminal kinase (JNK), in the hypothalamus was significantly decreased during cold exposure. p38α deficiency in the POA dramatically elevated energy expenditure owing to a marked increase in BAT thermogenesis, resulting in significantly decreased body weight gain and fat mass. Overexpression of p38α in the POA led to a dramatic increase in weight gain.Conclusions: These results demonstrate that p38α in the POA exacerbates obesity development, at least in part owing to a decrease in BAT thermogenesis. [ABSTRACT FROM AUTHOR]

Obesity is the result of energy intake chronically exceeding energy expenditure. Classical treatments against obesity do not provide a satisfactory long-term outcome for the majority of patients. After the demonstration of functional brown adipose tissue in human adults, great effort is being devoted to develop therapies based on the adipose tissue itself, through the conversion of fat-accumulating white adipose tissue into energy-dissipating brown adipose tissue. Anti-obesity treatments that exploit endogenous, pharmacological and nutritional factors to drive such conversion are especially in demand. In the present review, we summarize the current knowledge about the various molecules that can be applied in promoting white-to-brown adipose tissue conversion and energy expenditure and the cellular mechanisms involved. [ABSTRACT FROM AUTHOR]

Background: Adiponectin, protein secreted mainly by white adipose tissue, is an important factor linking the regulation of metabolic homeostasis and reproductive processes. The biological activity of the hormone is mediated via two distinct receptors, termed adiponectin receptor 1(AdipoR1) and adiponectin receptor 2 (AdipoR2). The present study analyzed mRNA and protein expression of AdipoR1 and AdipoR2 in the anterior (AP) and posterior (NP) pituitary of cyclic pigs. Methods: The total of 20 animals was assigned to one of four experimental groups (n = 5 per group) as follows: days 2-3 (early-luteal phase), 10-12 (mid-luteal phase), 14-16 (late-luteal phase), 17-19 (follicular phase) of the oestrous cycle. mRNA and protein expression were analyzed using real-time PCR and Western Blot methods, respectively. Results: The lowest AdipoR1 gene expression was detected in AP on days 10-12 relative to days 2-3 and 14-16 (p < 0.05). In NP, AdipoR1 mRNA levels were elevated on days 10-12 and 14-16 (p < 0.05). AdipoR2 gene expression in AP was the lowest on days 10-12, and an expression peak occurred on days 2-3 (p < 0.05). In NP, the lowest (p < 0.05) expression of AdipoR2 mRNA was noted on days 17-19. The AdipoR1 protein content in AP was the lowest on days 17-19 (p < 0.05), while in NP the variations in protein expression levels during the oestrous cycle were negligible. AdipoR2 protein in AP was most abundant on days 10-12, and it reached the lowest level on days 2-3 and 17-19 of the cycle (p < 0.05). The presence of AdipoR2 protein in NP was more pronounced on days 10-12 (p < 0.05). Conclusions: Our study was the first experiment to demonstrate that AdipoR1 and AdipoR2 mRNAs and proteins are present in the porcine pituitary and that adiponectin receptors expression is dependent on endocrine status of the animals. [ABSTRACT FROM AUTHOR]