Exercise training restores weight gain and attenuates hepatic inflammation in a rat model of non-celiac gluten sensitivity.

Gluten intolerance is associated with several disorders in the body. Although research has grown in recent years, the understanding of its impact on different tissues and the effects of physical exercise in mitigating health problems in the condition of gluten intolerance are still limited. Therefore, our objective was to test whether gliadin would affect metabolism and inflammation in liver tissue and whether aerobic physical exercise would mitigate the negative impacts of gliadin administration in rodents. Wistar rats were divided into exercised gliadin, gliadin, and control groups. Gliadin was administered by gavage from birth to 60 days of age. The rats in the exercised gliadin group performed an aerobic running exercise training protocol for 15 days. At the end of the experiments, physiological, histological, and molecular analyzes were performed in the study. Compared to the control group, the gliadin group had impaired weight gain and increased gluconeogenesis, lipogenesis, and inflammatory biomarkers in the liver. On the other hand, compared to the gliadin group, animals in the exercise-gliadin group had a recovery in body weight, improved insulin sensitivity, and a reduction in some gluconeogenesis, lipogenesis, and inflammatory biomarkers in the liver. In conclusion, our results revealed that the administration of gliadin from birth impaired weight gain and induced an increase in hepatic inflammatory cytokines, which was associated with an impairment of glycemic homeostasis in the liver, all of which were attenuated by adding aerobic exercise training in the gliadin group.

Aging reduces ABHD5 protein content in the adipose tissue of mice: The reversal effect of exercise.

Dysfunction of the adipose tissue metabolism is considered as a significant hallmark of aging. It has been proposed that α-ß hydrolase domain containing 5 (ABHD5) plays a critical role in the control of lipolysis. However, the role of ABHD5 in the control of lipolysis during aging or exercise is unknown. Here we combined the experimental mouse model with transcriptomic analyzes by using murine and human databases to explore the role of ABHD5 in the adipose tissue during aging and in response to exercise. Transcriptomic data revealed a downregulation of Abhd5 messenger RNA levels in the subcutaneous white adipose tissue (scWAT) over time in individuals from 20 to 69 years old. Aged mice displayed dramatic reduction of ABHD5 protein content and lipolytic-related proteins in the scWAT. Interestingly, 4 weeks of high-intensity interval training increased ABHD5 protein level and restored the lipolytic pathway in the scWAT of aged mice. Altogether, our findings demonstrated that aging affects ABHD5 content in the adipose tissue of mice and humans. Conversely, exercise increases ABHD5 activity, recovering the lipolytic activity in aged mice.

Taurine upregulates insulin signaling and mitochondrial metabolism in vitro but not in adipocytes of obese women.

OBJECTIVES: Based on taurine's beneficial roles in metabolic diseases in rodents and obese individuals, we investigated the effects of taurine supplementation on adipose tissue using transcriptome analysis, 3T3-L1 adipocytes, and subcutaneous white adipose tissue (scWAT) of obese women. METHODS: First, we applied bioinformatics analysis to evaluate the effect of the taurine synthesis pathway on the adipose tissue of several BXD mice strains. After that, using 3T3-L1 adipocytes, we investigated the effects of different taurine doses in proteins related to insulin signaling, lipid oxidation, and mitochondrial function. Finally, we evaluated the effects of taurine supplementation (3 grams, 8 wk) on the same proteins in the scWAT of obese women. RESULTS: The transcriptome analysis showed that the taurine biosynthesis pathway was positively associated with insulin signaling and mitochondrial metabolism in the scWAT of BXD mice. The experiments using 3T3-L1 cells highlighted that the taurine dosage has an essential function in taurine synthesis, insulin, and mitochondrial markers. In contrast, the 8-wk taurine administration did not change the basal insulin, proteins of the taurine synthesis or insulin pathways, lipid oxidation, or mitochondrial metabolism in the scWAT of obese women. CONCLUSIONS: For the first time, to our knowledge, we showed that supplementation with 3 g of taurine for 8 wk promoted no effect in the insulin signaling pathway in the scWAT of obese women. These findings bring new perspectives to investigate different taurine doses and the intervention period for human studies owing to the potential antiobesity activity of taurine.

Exercise alters the mitochondrial proteostasis and induces the mitonuclear imbalance and UPRmt in the hypothalamus of mice.

The maintenance of mitochondrial activity in hypothalamic neurons is determinant to the control of energy homeostasis in mammals. Disturbs in the mitochondrial proteostasis can trigger the mitonuclear imbalance and mitochondrial unfolded protein response (UPRmt) to guarantee the mitochondrial integrity and function. However, the role of mitonuclear imbalance and UPRmt in hypothalamic cells are unclear. Combining the transcriptomic analyses from BXD mice database and in vivo experiments, we demonstrated that physical training alters the mitochondrial proteostasis in the hypothalamus of C57BL/6J mice. This physical training elicited the mitonuclear protein imbalance, increasing the mtCO-1/Atp5a ratio, which was accompanied by high levels of UPRmt markers in the hypothalamus. Also, physical training increased the maximum mitochondrial respiratory capacity in the brain. Interestingly, the transcriptomic analysis across several strains of the isogenic BXD mice revealed that hypothalamic mitochondrial DNA-encoded genes were negatively correlated with body weight and several genes related to the orexigenic response. As expected, physical training reduced body weight and food intake. Interestingly, we found an abundance of mt-CO1, a mitochondrial DNA-encoded protein, in NPY-producing neurons in the lateral hypothalamus nucleus of exercised mice. Collectively, our data demonstrated that physical training altered the mitochondrial proteostasis and induced the mitonuclear protein imbalance and UPRmt in hypothalamic cells.

Acute physical exercise increases PI3K-p110α protein content in the hypothalamus of obese mice.

The anatomy of the hypothalamus includes many nuclei and a complex network of neurocircuits. In this context, some hypothalamic nuclei reside closer to the blood-brain barrier, allowing communication with the peripheral organs through some molecules, such as leptin. Leptin is considered the main adipokine for energy homeostasis control. Furthermore, leptin signalling in the hypothalamus can communicate with insulin signalling through the activation of phosphoinositide 3-kinase (PI3k). Previous data suggest that isoforms of PI3k are necessary to mediate insulin action in the hypothalamus. However, obese animals show impairment in the central signalling of these hormones. Thus, in the current study, we evaluated the role of acute exercise in the leptin and insulin pathways in the hypothalamus, as well as in food intake control in obese mice. Although acute physical exercise was not able to modulate leptin signalling, this protocol suppressed the increase in the suppressor of cytokine signalling 3 (SOCS3) protein levels. In addition, acute exercise increased the content of PI3k-p110α protein in the hypothalamus. The exercised animals showed a strong tendency to reduction in cumulative food intake. For the first time, our results indicate physical exercise can increase PI3k-p110α protein content in the hypothalamus of obese mice and regulate food intake.

Exercise decreases CLK2 in the liver of obese mice and prevents hepatic fat accumulation.

The accumulation of fatty acids in the liver associated with obesity condition is also known as nonalcoholic fatty liver disease (NAFLD). The impaired fat oxidation in obesity condition leads to increased hepatic fat accumulation and increased metabolic syndrome risk. On the other hand, physical exercise has been demonstrated as a potent strategy in the prevention of NAFLD. Also, these beneficial effects of exercise occur through different mechanisms. Recently, the Cdc2-like kinase (CLK2) protein was associated with the suppression of fatty acid oxidation and hepatic ketogenesis. Thus, obese animals demonstrated elevated levels of hepatic CLK2 and decreased fat acid oxidation. Here, we explored the effects of chronic physical exercise in the hepatic metabolism of obese mice. Swiss mice were distributed in Lean, Obese (fed with high-fat diet during 16 weeks) and Trained Obese group (fed with high-fat diet during 16 weeks and exercised (at 60% exhaustion velocity during 1 h/5 days/week) during 8 weeks. In our results, the obese animals showed insulin resistance, increased hepatic CLK2 content and increased hepatic fat accumulation compared to the Lean group. Otherwise, the chronic physical exercise improved insulin resistance state, prevented the increased CLK2 in the liver and attenuated hepatic fat accumulation. In summary, these data reveal a new protein involved in the prevention of hepatic fat accumulation after chronic physical exercise. More studies can evidence the negative role of CLK2 in the control of liver metabolism, contributing to the improvement of insulin resistance, obesity, and type 2 diabetes.

Obesity Increases Mitogen-Activated Protein Kinase Phosphatase-3 Levels in the Hypothalamus of Mice.

Mitogen-activated Protein Kinase Phosphatase 3 (MKP-3) has been involved in the negative regulation of insulin signaling. The absence of MKP-3 is also associated with reduced adiposity, increased energy expenditure and improved insulin sensitivity. The MKP-3 is known as the main Erk1/2 phosphatase and FoxO1 activator, which has repercussions on the gluconeogenesis pathway and hyperglycemia in obese mice. Recently, we showed that MKP-3 overexpression decreases FoxO1 phosphorylation in the hypothalamus of lean mice. However, the hypothalamic interaction between MKP-3 and FoxO1 during obesity was not investigated yet. Here, the MKP-3 expression and the effects on food intake and energy expenditure, were investigated in high-fat diet-induced obese mice. The results indicate that obesity in mice increased the MKP-3 protein content in the hypothalamus. This hypothalamic upregulation led to an increase of food intake, adiposity, and body weight. Furthermore, the obese mice with increased MKP-3 showed an insulin signaling impairment with reduction of insulin-induced FoxO1 and Erk1/2 phosphorylation in the hypothalamus. Moreover, a bioinformatics analysis of data demonstrated that hypothalamic MKP-3 mRNA levels were positively correlated with body weight and negatively correlated to oxygen consumption (VO2) in BXD mice. Taken together, our study reports that obesity is associated with increased protein levels of hypothalamic MKP-3, which is related to the reduction of FoxO1 and Erk1/2 phosphorylation in the hypothalamus as well as to an increase in body weight and a reduction in energy expenditure.