Metabotropic glutamate receptor 5 knockout rescues obesity phenotype in a mouse model of Huntington's disease.

Obesity represents a global health problem and is characterized by metabolic dysfunctions and a low-grade chronic inflammatory state, which can increase the risk of comorbidities, such as atherosclerosis, diabetes and insulin resistance. Here we tested the hypothesis that the genetic deletion of metabotropic glutamate receptor 5 (mGluR5) may rescue metabolic and inflammatory features present in BACHD mice, a mouse model of Huntington's disease (HD) with an obese phenotype. For that, we crossed BACHD and mGluR5 knockout mice (mGluR5-/-) in order to obtain the following groups: Wild type (WT), mGluR5-/-, BACHD and BACHD/mGluR5-/- (double mutant mice). Our results showed that the double mutant mice present decreased body weight as compared to BACHD mice in all tested ages and reduced visceral adiposity as compared to BACHD at 6 months of age. Additionally, 12-month-old double mutant mice present increased adipose tissue levels of adiponectin, decreased leptin levels, and increased IL-10/TNF ratio as compared to BACHD mice. Taken together, our preliminary data propose that the absence of mGluR5 reduce weight gain and visceral adiposity in BACHD mice, along with a decrease in the inflammatory state in the visceral adipose tissue (VAT), which may indicate that mGluR5 may play a role in adiposity modulation.

Negative Modulation of the Metabotropic Glutamate Receptor Type 5 as a Potential Therapeutic Strategy in Obesity and Binge-Like Eating Behavior.

Obesity is a multifactorial disease, which in turn contributes to the onset of comorbidities, such as diabetes and atherosclerosis. Moreover, there are only few options available for treating obesity, and most current pharmacotherapy causes severe adverse effects, while offering minimal weight loss. Literature shows that metabotropic glutamate receptor 5 (mGluR5) modulates central reward pathways. Herein, we evaluated the effect of VU0409106, a negative allosteric modulator (NAM) of mGluR5 in regulating feeding and obesity parameters. Diet-induced obese C57BL/6 mice were treated for 14 days with VU0409106, and food intake, body weight, inflammatory/hormonal levels, and behavioral tests were performed. Our data suggest reduction of feeding, body weight, and adipose tissue inflammation in mice treated with high-fat diet (HFD) after chronic treatment with VU0409106. Furthermore, a negative modulation of mGluR5 also reduces binge-like eating, the most common type of eating disorder. Altogether, our results pointed out mGluR5 as a potential target for treating obesity, as well as related disorders.

Expression of adiponectin and its receptors (AdipoR1 and AdipoR2) in goat ovary and its effect on oocyte nuclear maturation in vitro.

Adiponectin is an adipokine secreted primarily by adipocytes and is involved in the control of male and female reproductive functions. Circulating levels of adiponectin are inversely correlated with body fat mass, and its biological effects are predominantly mediated through two receptors, AdipoR1 and AdipoR2. The aim of the present study was to verify the expression of the adiponectin system (adiponectin and its receptors, AdipoR1 and AdipoR2) in goat ovary using qPCR and immunohistochemistry analyses and further investigate the in vitro effects of recombinant adiponectin (5 µg/mL and 10 µg/mL) on goat oocyte nuclear maturation. We demonstrated that the mRNA and proteins of the adiponectin system are present in goat ovary. Gene and protein expression of AdipoR1 and AdipoR2 was detected in follicular cells (oocyte, cumulus, granulosa and theca) of small and large antral follicles, while adiponectin mRNA was not detected in oocytes from small and large follicles or in large follicle cumulus cells. Finally, addition of various concentrations of adiponectin in maturation medium affected the number of oocytes that reached metaphase II. In conclusion, in the present study, we detected expression of adiponectin and its receptors AdipoR1 and AdipoR2 in goat ovarian follicles. Furthermore, we demonstrated that recombinant adiponectin increases nuclear maturation of goat oocytes in vitro.