Rho-Kinase Is Differentially Expressed in the Adipose Tissue of Rodent and Human in Response to Aging, Sex, and Acute Exercise

White adipose tissue (WAT) controls energy storage, expenditure, and endocrine function. Rho-kinase (ROCK) is related to impaired thermogenesis, downregulation of preadipocyte differentiation, and adipokine production. Furthermore, WAT ROCK responds to metabolic stress from high-fat diets or diabetes. However, ROCK distribution in adipose depots and its response to aging and sex remain unclear. Thus, we aim to investigate ROCK function in adipose tissue of rodent and human in response to aging and sex. We observed specific differences in the ROCK1/2 distribution in inguinal WAT (ingWAT), perigonadal WAT (pgWAT), and brown adipose tissue of male and female rodents. However, ROCK2 expression was lower in female ingWAT compared with males, a fact that was not observed in the other depots. In the pgWAT and ingWAT of male and female rodents, ROCK activity increased during development. Moreover, middle-aged female rodents and humans showed downregulation in ROCK activity after acute physical exercise. Interestingly, ROCK levels were associated with several inflammatory markers both in rats and humans WAT (Nfkb1, Tnf, Il1b, Il6, and Mcp1). Induction of cell senescence by etoposide elevates ROCK activity in human preadipocytes; however, silencing ROCK1/2 demonstrates improvement in the inflammatory and cell senescence state. Using public databases, several pathways were strongly associated with ROCK modulation in WAT. In summary, WAT ROCK increases with development in association with inflammatory markers. Further, ROCK activity was attenuated by acute physical exercise, implicating it as a possible therapeutic target for metabolism improvement mediated by adipose tissue inflammatory state changes.

Physical exercise elicits UPRmt in the skeletal muscle: The role of c-Jun N-terminal kinase

OBJECTIVE

The mitochondrial unfolded protein response (UPRmt) is an adaptive cellular response to stress to ensure mitochondrial proteostasis and function. Here we explore the capacity of physical exercise to induce UPRmt in the skeletal muscle.

METHODS

Therefore, we combined mouse models of exercise (swimming and treadmill running), pharmacological intervention, and bioinformatics analyses.

RESULTS

Firstly, RNA sequencing and Western blotting analysis revealed that an acute aerobic session stimulated several mitostress-related genes and protein content in muscle, including the UPRmt markers. Conversely, using a large panel of isogenic strains of BXD mice, we identified that BXD73a and 73b strains displayed low levels of several UPRmt-related genes in the skeletal muscle, and this genotypic feature was accompanied by body weight gain, lower locomotor activity, and aerobic capacity. Finally, we identified that c-Jun N-terminal kinase (JNK) activation was critical in exercise-induced UPRmt in the skeletal muscle since pharmacological JNK pathway inhibition blunted exercise-induced UPRmt markers in mice muscle.

CONCLUSION

Our findings provide new insights into how exercise triggers mitostress signals toward the oxidative capacity in the skeletal muscle.

Time-restricted feeding combined with resistance exercise prevents obesity and improves lipid metabolism in the liver of mice fed a high-fat diet

Nonalcoholic fatty liver disease (NAFLD), a condition characterized by the accumulation of fat in the liver, is estimated to be the most common liver disease worldwide. Obesity is a major risk factor and contributor, and, accordingly, weight loss can improve NAFLD. Previous studies in preclinical models of diet-induced obesity and fatty liver disease have shown the independent benefits of resistance exercise training (RT) and time-restricted feeding (TRF) in preventing weight gain and hepatic build-up of fat. Here, we tested the combined effect of TRF and RT on obesity and NAFLD in mice fed a high-fat diet. Our results showed that both TRF-8-h food access in the active phase-and RT-consisting of three weekly sessions of ladder climbing-attenuated body weight gain, improved glycemic homeostasis, and decreased the accumulation of lipids in the liver. TRF combined with RT improved the respiratory exchange rate, energy expenditure, and mitochondrial respiration in the liver. Furthermore, gene expression analysis in the liver revealed lower mRNA expression of lipogenesis and inflammation genes along with increased mRNA of fatty acid oxidation genes in the TRF + RT group. Importantly, combined TRF + RT was shown to be more efficient in preventing obesity and metabolic disorders. In conclusion, TRF and RT exert complementary actions compared with isolated interventions, with significant effects on metabolic disorders and NAFLD in mice.NEW & NOTEWORTHY Whether time-restricted feeding (TRF) combined with resistance exercise training (RT) may be more efficient compared with these interventions alone is still unclear. We show that when combined with RT, TRF provided additional benefits, being more effective in increasing energy expenditure, preventing weight gain, and regulating glycemic homeostasis than each intervention alone. Thus, our results demonstrate that TRF and RT have complementary actions on some synergistic pathways that prevented obesity and hepatic liver accumulation.

Short-term strength exercise reduces the macrophage M1/M2 ratio in white adipose tissue of obese animals

Obesity can exacerbate the systemic inflammatory process, leading to increased infiltration of monocytes in white adipose tissue (WAT) and polarization of these cells into pro-inflammatory M1 macrophages, while reducing the population of anti-inflammatory M2 macrophages. Aerobic exercise has been shown to be effective in reducing the pro-inflammatory profile. However, the impact of strength training and the duration of training on macrophage polarization in the WAT of obese individuals have not been widely studied. Therefore, our aim was to investigate the effects of resistance exercise on macrophage infiltration and polarization in the epididymal and subcutaneous adipose tissue of obese mice. We compared the following groups: Control (CT), Obese (OB), Obese 7-day strength training (STO7d), and Obese 15-day strength training (STO15d). Macrophage populations were evaluated by flow cytometry: total macrophages (F4/80+), M1 (CD11c), and M2 (CD206) macrophages. Our results demonstrated that both training protocols improved peripheral insulin sensitivity by increasing AKT phosphorylation (Ser473). Specifically, the 7-day training regimen reduced total macrophage infiltration and M2 macrophage levels without altering M1 levels. In the STO15d group, significant differences were observed in total macrophage levels, M1 macrophages, and the M1/M2 ratio compared to the OB group. In the epididymal tissue, a reduction in the M1/M2 ratio was observed in the STO7d group. Overall, our data demonstrate that 15 days of strength exercise can reduce the M1/M2 ratio of macrophages in white adipose tissue.

The Early Impact of Diets Enriched with Saturated and Unsaturated Fatty Acids on Intestinal Inflammation and Tight Junctions

The gut has been suggested as the first organ to be affected by unbalanced diets contributing to the obesogenic process. This study aimed to test a short time-course exposition model to a known pro- or anti-inflammatory enriched fatty diet to understand the early gut alterations. Male mice were exposed to the chow diet (CT), high-fat (HF) diet, or a high-fat diet partially replaced on flaxseed oil (FS), rich in omega-3 (ω3), for 14 days. HF and FS increased the total body weight mass compared with the CT group, but FS reduced the epididymal fat depot compared to HF. The bioinformatics from mice and human databases showed the Zo1-Ocln-Cldn7 tight junctions as the main protein-triad. In the ileum, the HF diet has increased IL1β transcript and IL1β, TNFα, and CD11b proteins, but reduced the tight junctions (Zo1, Ocln, and Cld7) compared to the CT group. Despite the FS diet being partially efficient in protecting the ileum against inflammation, the tight junctions were increased, compared to the HF group. The GPR120 and GPR40 receptors were unaffected by diets, but GPR120 was co-localized on the surface of ileum macrophages. The short period of a high-fat diet was enough to start the obesogenic process, ileum inflammation, and reduce the tight junctions. Flaxseed oil did not protect efficiently against dysmetabolism. Still, it increased the tight junctions, even without alteration on inflammatory parameters, suggesting the protection against gut permeability during early obesity development.

Position statement on nutrition therapy for overweight and obesity: nutrition department of the Brazilian association for the study of obesity and metabolic syndrome (ABESO-2022)

Obesity is a chronic disease resulting from multifactorial causes mainly related to lifestyle (sedentary lifestyle, inadequate eating habits) and to other conditions such as genetic, hereditary, psychological, cultural, and ethnic factors. The weight loss process is slow and complex, and involves lifestyle changes with an emphasis on nutritional therapy, physical activity practice, psychological interventions, and pharmacological or surgical treatment. Because the management of obesity is a long-term process, it is essential that the nutritional treatment contributes to the maintenance of the individual's global health. The main diet-related causes associated with excess weight are the high consumption of ultraprocessed foods, which are high in fats, sugars, and have high energy density; increased portion sizes; and low intake of fruits, vegetables, and grains. In addition, some situations negatively interfere with the weight loss process, such as fad diets that involve the belief in superfoods, the use of teas and phytotherapics, or even the avoidance of certain food groups, as has currently been the case for foods that are sources of carbohydrates. Individuals with obesity are often exposed to fad diets and, on a recurring basis, adhere to proposals with promises of quick solutions, which are not supported by the scientific literature. The adoption of a dietary pattern combining foods such as grains, lean meats, low-fat dairy, fruits, and vegetables, associated with an energy deficit, is the nutritional treatment recommended by the main international guidelines. Moreover, an emphasis on behavioral aspects including motivational interviewing and the encouragement for the individual to develop skills will contribute to achieve and maintain a healthy weight. Therefore, this Position Statement was prepared based on the analysis of the main randomized controlled studies and meta-analyses that tested different nutrition interventions for weight loss. Topics in the frontier of knowledge such as gut microbiota, inflammation, and nutritional genomics, as well as the processes involved in weight regain, were included in this document. This Position Statement was prepared by the Nutrition Department of the Brazilian Association for the Study of Obesity and Metabolic Syndrome (ABESO), with the collaboration of dietitians from research and clinical fields with an emphasis on strategies for weight loss.

Effects of short-term endurance and strength exercise in the molecular regulation of skeletal muscle in hyperinsulinemic and hyperglycemic Slc2a4+/- mice

OBJECTIVE

Intriguingly, hyperinsulinemia, and hyperglycemia can predispose insulin resistance, obesity, and type 2 diabetes, leading to metabolic disturbances. Conversely, physical exercise stimulates skeletal muscle glucose uptake, improving whole-body glucose homeostasis. Therefore, we investigated the impact of short-term physical activity in a mouse model (Slc2a4^+/-) that spontaneously develops hyperinsulinemia and hyperglycemia even when fed on a chow diet.

METHODS

Slc2a4^+/- mice were used, that performed 5 days of endurance or strength exercise training. Further analysis included physiological tests (GTT and ITT), skeletal muscle glucose uptake, skeletal muscle RNA-sequencing, mitochondrial function, and experiments with C2C12 cell line.

RESULTS

When Slc2a4^+/- mice were submitted to the endurance or strength training protocol, improvements were observed in the skeletal muscle glucose uptake and glucose metabolism, associated with broad transcriptomic modulation, that was, in part, related to mitochondrial adaptations. The endurance training, but not the strength protocol, was effective in improving skeletal muscle mitochondrial activity and unfolded protein response markers (UPRmt). Moreover, experiments with C2C12 cells indicated that insulin or glucose levels could contribute to these mitochondrial adaptations in skeletal muscle.

CONCLUSIONS

Both short-term exercise protocols were efficient in whole-body glucose homeostasis and insulin resistance. While endurance exercise plays an important role in transcriptome and mitochondrial activity, strength exercise mostly affects post-translational mechanisms and protein synthesis in skeletal muscle. Thus, the performance of both types of physical exercise proved to be a very effective way to mitigate the impacts of hyperglycemia and hyperinsulinemia in the Slc2a4^+/- mouse model.

Short-chain fatty acids are associated with adiposity, energy and glucose homeostasis among different metabolic phenotypes in the Nutritionists' Health Study

BACKGROUND AND AIMS

The gut microbiome is associated with obesity, mainly mediated by bacteria-produced short-chain fatty acids (SCFAs). It is unknown how SCFA concentrations are associated with the phenotypes metabolically healthy normal weight (MHNW), metabolically unhealthy normal weight (MUNW), metabolically healthy obese/overweight (MHO), and metabolically unhealthy obese/overweight (MUO). We compared plasma and fecal SCFA concentrations among adult women categorized according to the metabolic phenotypes mentioned above and examined associations between SCFA and adiposity and components of energy and glucose homeostasis.

METHODS

This was a cross-sectional study involving 111 participants. Body composition was assessed by DEXA. Energy and glycemic homeostasis were assessed by the standard mixed-meal tolerance test coupled with indirect calorimetry. SCFAs were quantified by gas chromatography and mass spectrometry.

RESULTS

Only plasma propionate was increased in the MHNW phenotype compared to the MHO and MUO phenotypes [p < 0.05]. Fecal propionate and butyrate concentrations and plasma propionate concentrations were inversely associated with total and visceral adiposity [p < 0.05]. Fecal and plasma SCFA concentrations were associated with reduced glucose, insulin and HbA1c levels, increased fasting and postprandial GLP-1 levels; and more preserved beta-cell function [p < 0.05]. Fecal and plasma SCFA concentrations were positively correlated with resting energy expenditure and lipid oxidation rate and inversely correlated with the oxidation rate of carbohydrates [p < 0.05].

CONCLUSION

These findings reinforce the concept that fecal and plasma SCFA concentrations are linked to specific components of energy and glucose homeostasis; and body adiposity. However, it was not possible to discriminate the different metabolic phenotypes of adiposity based on the determination of fecal SCFA concentrations.

Short-term flaxseed oil, rich in omega 3, protects mice against metabolic damage caused by high-fat diet, but not inflammation

It is known that long-term high-fat diet (HF) feeding drastically affects the adipose tissue, contributing to metabolic disorders. Recently, short-term HF consumption was shown to affect different neuronal signaling pathways. Thus, we aimed to evaluate the inflammatory effects of a short-term HF and whether a diet containing omega-3 fatty acid fats from flaxseed oil (FS) has protective effects. Mice were divided into three groups for 3 d, according to their diets: Control group (CT), HF, or FS for 3 d. Lipid profiles were assessed through mass spectrometry and inflammatory markers by RT-qPCR and Western blotting. After short-term HF, mice increased food intake, body weight, adiposity, and fasting glucose. Increased mRNA content of Ccl2 and Tnf was demonstrated in the HF compared to CT in mesenteric adipose tissue. In the liver, TNFα protein was higher in the HF group than in CT, followed by a decreased polyunsaturated fatty acids tissue incorporation in HF. On the other hand, the consumption of FS reduced food intake and fasting glucose, as well as increased omega-3 fatty acid incorporation in MAT and the liver. However, short-term FS was insufficient to control the early inflammation triggered by HF in MAT and the liver. These data demonstrated that a 3-d HF diet is enough to damage glucose homeostasis and trigger inflammation. In contrast, short-term FS protects against increased food intake and fasting glucose but not inflammation in mice.

Short-term physical exercise controls age-related hyperinsulinemia and improves hepatic metabolism in aged rodents

PURPOSE

Aging is associated with changes in glucose homeostasis related to both decreased insulin secretion and/or impaired insulin action, contributing to the high prevalence of type 2 diabetes (T2D) in the elderly population. Additionally, studies are showing that chronically high levels of circulating insulin can also lead to insulin resistance. In contrast, physical exercise has been a strategy used to improve insulin sensitivity and metabolic health. However, the molecular alterations resulting from the effects of physical exercise in the liver on age-related hyperinsulinemia conditions are not yet fully established. This study aimed to investigate the effects of 7 days of aerobic exercise on hepatic metabolism in aged hyperinsulinemic rats (i.e., Wistar and F344) and in Slc2a4^+/- mice (hyperglycemic and hyperinsulinemic mice).

RESULTS

Both aged models showed alterations in insulin and glucose tolerance, which were associated with essential changes in hepatic fat metabolism (lipogenesis, gluconeogenesis, and inflammation). In contrast, 7 days of physical exercise was efficient in improving whole-body glucose and insulin sensitivity, and hepatic metabolism. The Slc2a4^+/- mice presented significant metabolic impairments (insulin resistance and hepatic fat accumulation) that were improved by short-term exercise training. In this scenario, high circulating insulin may be an important contributor to age-related insulin resistance and hepatic disarrangements in some specific conditions.

CONCLUSION

In conclusion, our data demonstrated that short-term aerobic exercise was able to control mechanisms related to hepatic fat accumulation and insulin sensitivity in aged rodents. These effects could contribute to late-life metabolic health and prevent the development/progression of age-related T2D.

Combined effects of yacon flour and probiotic yogurt on the metabolic parameters and inflammatory and insulin signaling proteins in high-fat-diet-induced obese mice

BACKGROUND

Prebiotics and probiotics may be effective dietary components that can alter the gut microbiota of the host and, consequently, overcome imbalances associated with obesity. This work aimed to evaluate the synergistic and isolated effects and mechanisms by which probiotic yogurt containing Bifidobacterium animalis and/or Lactobacillus acidophilus and yacon flour alter metabolic parameters and inflammatory and insulin signaling proteins in diet-induced obese mice. Swiss mice were fed a high-fat diet (n = 48) or a standard diet (control; n = 6) for 56 days. The 42 mice that gained the most weight were selected and divided into seven groups that received different combinations of probiotic yogurt and yacon flour. After 30 days, biochemical parameters (blood glucose, serum total cholesterol, and triacylglycerols), crude fat excretion in feces, and periepididymal fat were assessed and an immunoblotting analysis of insulin signaling proteins and interleukin-1β was conducted.

RESULTS

The combination of yacon flour and a yogurt with two strains of probiotics exerted positive effects on the parameters evaluated, such as decreased body weight (-6.5%; P < 0.05), fasting glucose (-23.1%; P < 0.05), and triacylglycerol levels (-21.4%; P < 0.05) and decreased periepididymal fat accumulation (-44.2%; P < 0.05). There was a decrease in inflammatory markers (P < 0.001) and an improvement in insulin signaling (P < 0.001).

CONCLUSIONS

The combination of a prebiotic with two strains of probiotics in a food matrix may exert a protective effect against obesity-associated inflammation, improving insulin resistance, even in the short term. © 2022 Society of Chemical Industry.

Omega-3 pleiad: The multipoint anti-inflammatory strategy

Omega 3 (ω3) fatty acids have been described since the 1980s as promising anti-inflammatory substances. Prostaglandin and leukotriene modulation were exhaustively explored as the main reason for ω3 beneficial outcomes. However, during the early 2000s, after the human genome decoding advent, the nutrigenomic approaches exhibited an impressive plethora of ω3 targets, now under the molecular point of view. Different G protein-coupled receptors (GPCRs) recognizing ω3 and its derivatives appear to be responsible for blocking inflammation and insulin-sensitizing effects. A new class of ω3-derived substances, such as maresins, resolvins, and protectins, increases ω3 actions. Inflammasome disruption, the presence of GPR120 on immune cell surfaces, and intracellular crosstalk signaling mediated by PPARγ compose the last discoveries regarding the multipoint anti-inflammatory targets for this nutrient. This review shows a detailed mechanistic proposal to understand ω3 fatty acid action over the inflammatory environment in the background of several chronic diseases.

Evidence for a neuromuscular circuit involving hypothalamic interleukin-6 in the control of skeletal muscle metabolism

Hypothalamic interleukin-6 (IL6) exerts a broad metabolic control. Here, we demonstrated that IL6 activates the ERK1/2 pathway in the ventromedial hypothalamus (VMH), stimulating AMPK/ACC signaling and fatty acid oxidation in mouse skeletal muscle. Bioinformatics analysis revealed that the hypothalamic IL6/ERK1/2 axis is closely associated with fatty acid oxidation- and mitochondrial-related genes in the skeletal muscle of isogenic BXD mouse strains and humans. We showed that the hypothalamic IL6/ERK1/2 pathway requires the α2-adrenergic pathway to modify fatty acid skeletal muscle metabolism. To address the physiological relevance of these findings, we demonstrated that this neuromuscular circuit is required to underpin AMPK/ACC signaling activation and fatty acid oxidation after exercise. Last, the selective down-regulation of IL6 receptor in VMH abolished the effects of exercise to sustain AMPK and ACC phosphorylation and fatty acid oxidation in the muscle after exercise. Together, these data demonstrated that the IL6/ERK axis in VMH controls fatty acid metabolism in the skeletal muscle.

RESISTANCE EXERCISE ATTENUATES IKKε PHOSPHORYLATION AND HEPATIC FAT ACCUMULATION OF OBESE MICE

Obesity is associated with low-grade inflammation and disturbances in hepatic metabolism. This study aimed to investigate the effects of resistance exercise on inflammatory signaling related to IKKepsilon protein (IKKɛ) and on hepatic fat accumulation in obese mice. Male Swiss mice were distributed into three groups: control (CTL) fed with standard chow; obese (OB) mice induced by a high-fat diet (HFD); obese exercised (OB+RE) mice fed with HFD and submitted to a resistance exercise training. The resistance exercise training protocol consisted of 20 sets/3 ladder climbs for eight weeks, three times/week on alternate days. The training overload was equivalent to 70% of the maximum load supported by the rodent. Assays were performed to evaluate weight gain, hepatic fat content, fasting glucose, insulin sensitivity, IKKɛ phosphorylation, and proteins related to insulin signaling and lipogenesis in the liver. Mice that received the high-fat diet showed greater adiposity, impaired insulin sensitivity, increased fasting glucose, and increased hepatic fat accumulation. These results were accompanied by an increase in IKKɛ phosphorylation and lipogenesis-related proteins such as cluster of differentiation 36 (CD36) and fatty acid synthase (FAS) in the liver of obese mice. In contrast, exercised mice showed lower body weight and adiposity evolution throughout the experiment. In addition, resistance exercise suppressed the effects of the high-fat diet by reducing IKKɛ phosphorylation and hepatic fat content. In conclusion, resistance exercise training improves hepatic fat metabolism and glycemic homeostasis, which are, at least in part, linked to the antiinflammatory effect of reduced IKKɛ phosphorylation in the liver of obese mice. This article is protected by copyright. All rights reserved.

Omega-3 mechanism of action in inflammation and endoplasmic reticulum stress in mononuclear cells from overweight non-alcoholic fatty liver disease participants: study protocol for the "Brazilian Omega Study" (BROS)-a randomized controlled trial

Abstract

The low-grade inflammation is pivotal in obesity and its comorbidities; however, the inflammatory proteins are out of target for traditional drug therapy. Omega-3 (ω3) fatty acids can modulate the downstream signaling of Toll-like receptor (TLR) and tumor necrosis factor-α receptor (TNFα) through GPR120, a G-protein-coupled receptor, a mechanism not yet elucidated in humans. This work aims to investigate if the ω3 supplementation, at a feasible level below the previously recommended level in the literature, is enough to disrupt the inflammation and endoplasmic reticulum stress (ER-stress), and also if in acute treatment (3 h) ω3 can activate the GPR120 in peripheral blood mononuclear cells (PBMC) and leukocytes from overweight non-alcoholic fatty liver disease (NAFLD) participants. The R270H variant of the Ffar4 (GPR120 gene) will also be explored about molecular responses and blood lipid profiles. A triple-blind, prospective clinical trial will be conducted in overweight men and women, aged 19–75 years, randomized into placebo or supplemented (2.2 g of ω3 [EPA+DHA]) groups for 28 days. For sample calculation, it was considered the variation of TNFα protein and a 40% dropout rate, obtaining 22 individuals in each group. Volunteers will be recruited among patients with NAFLD diagnosis. Anthropometric parameters, food intake, physical activity, total serum lipids, complete fatty acid blood profile, and glycemia will be evaluated pre- and post-supplementation. In the PBMC and neutrophils, the protein content and gene expression of markers related to inflammation (TNFα, MCP1, IL1β, IL6, IL10, JNK, and TAK1), ER-stress (ATF1, ATF6, IRE1, XBP1, CHOP, eIF2α, eIF4, HSP), and ω3 pathway (GPR120, β-arrestin2, Tab1/2, and TAK1) will be evaluated using Western blot and RT-qPCR. Participants will be genotyped for the R270H (rs116454156) variant using the TaqMan assay. It is hypothesized that attenuation of inflammation and ER-stress signaling pathways in overweight and NAFLD participants will be achieved through ω3 supplementation through binding to the GPR120 receptor.

Trial registration

ClinicalTrials.gov #RBR-7x8tbx. Registered on May 10, 2018, with the Brazilian Registry of Clinical Trials.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05702-x.

12,13-diHOME as a new therapeutic target for metabolic diseases

Lipokines are bioactive compounds, derived from adipose tissue depots, that control several molecular signaling pathways. Recently, 12,13-dihydroxy-9Z-octadecenoic acid (12,13-diHOME), an oxylipin, has gained prominence in the scientific literature. An increase in circulating 12,13-diHOME has been associated with improved metabolic health, and the action of this molecule appears to be mediated by brown adipose tissue (BAT). Scientific evidence indicates that the increase in serum levels of 12,13-diHOME caused by stimuli such as physical exercise and exposure to cold may favor the absorption of fatty acids by brown adipose tissue and stimulate the browning process in white adipose tissue (WAT). Thus, strategies capable of increasing 12,13-diHOME levels may be promising for the prevention and treatment of obesity and metabolic diseases. This review explores the relationship of 12,13-diHOME with brown adipose tissue and its role in the metabolic health context, as well as the signaling pathways involved between 12,13-diHOME and BAT.

Short-term combined training reduces hepatic steatosis and improves hepatic insulin signaling

Hepatic steatosis is directly associated with hepatic inflammation and insulin resistance, which is correlated with hyperglycemia and type 2 diabetes mellitus (T2DM). Aerobic and strength training have been pointed out as efficient strategies against hepatic steatosis. However, little is known about the effects of the combination of those two protocols on hepatic steatosis. Therefore, this study aimed to evaluate the impact of short-term combined training (STCT) on glucose homeostasis and in the synthesis and oxidation of fat in the liver of obesity-induced mice with hepatic steatosis. Swiss mice were distributed into three groups: control lean (CTL), sedentary obese (OB), and combined training obese (CTO). The CTO group performed the STCT protocol, which consisted of strength and aerobic exercises in the same session. The protocol lasted seven days. The CTO group reduced the glucose levels and fatty liver when compared to the OB group. Interestingly, these results were observed even without reductions in body adiposity. CTO group also showed increased hepatic insulin sensitivity, with lower hepatic glucose production (HGP). STCT reduced the expression of the lipogenic genes Fasn and Scd1 and hepatic inflammation, as well as increased the ACC phosphorylation and the oxidative genes Cpt1a and Ppara, reverting the complications caused by obesity. Since this protocol increased lipid oxidation and reduced hepatic lipogenesis, regardless of body fat mass decrease, it can be considered an effective non-pharmacological strategy for the treatment of hepatic steatosis.

Taurine supplementation in conjunction with exercise modulated cytokines and improved subcutaneous white adipose tissue plasticity in obese women

Interventions that can modulate subcutaneous white adipose tissue (scWAT) function, such as exercise training and nutritional components, like taurine, modulate the inflammatory process, therefore, may represent strategies for obesity treatment. We investigated the effects of taurine supplementation in conjunction with exercise on inflammatory and oxidative stress markers in plasma and scWAT of obese women. Sixteen obese women were randomized into two groups: Taurine supplementation group (Tau, n = 8) and Taurine supplementation + exercise group (Tau + Exe, n = 8). The intervention was composed of daily taurine supplementation (3 g) and exercise training for 8 weeks. Anthropometry, body fat composition, and markers of inflammatory and oxidative stress were determined in plasma and scWAT biopsy samples before and after the intervention. We found that, although taurine supplementation increased taurine plasma levels, no changes were observed for the anthropometric characteristics. However, Tau alone decreased interleukin-6 (IL-6), and in conjunction with exercise (Tau + Exe), increased anti-inflammatory interleukins (IL-15 and IL10), followed by reduced IL1β gene expression in the scWAT of obese women. Tau and Tau + Exe groups presented reduced adipocyte size and increased connective tissue and multilocular droplets. In conclusion, taurine supplementation in conjunction with exercise modulated levels of inflammatory markers in plasma and scWAT, and improved scWAT plasticity in obese women, promoting protection against obesity-induced inflammation. TRN NCT04279600 retrospectively registered on August 18, 2019.

Short-Term Strength Exercise Reduces Hepatic Insulin Resistance in Obese Mice by Reducing PTP1B Content, Regardless of Changes in Body Weight

Obesity is closely related to insulin resistance and type 2 diabetes genesis. The liver is a key organ to glucose homeostasis since insulin resistance in this organ increases hepatic glucose production (HGP) and fasting hyperglycemia. The protein-tyrosine phosphatase 1B (PTP1B) may dephosphorylate the IR and IRS, contributing to insulin resistance in this organ. Aerobic exercise is a great strategy to increase insulin action in the liver by reducing the PTP1B content. In contrast, no study has shown the direct effects of strength training on the hepatic metabolism of PTP1B. Therefore, this study aims to investigate the effects of short-term strength exercise (STSE) on hepatic insulin sensitivity and PTP1B content in obese mice, regardless of body weight change. To achieve this goal, obese Swiss mice were submitted to a strength exercise protocol lasting 15 days. The results showed that STSE increased Akt phosphorylation in the liver and enhanced the control of HGP during the pyruvate tolerance test. Furthermore, sedentary obese animals increased PTP1B content and decreased IRS-1/2 tyrosine phosphorylation; however, STSE was able to reverse this scenario. Therefore, we conclude that STSE is an important strategy to improve the hepatic insulin sensitivity and HGP by reducing the PTP1B content in the liver of obese mice, regardless of changes in body weight.

The protective roles of clusterin in ocular diseases caused by obesity and diabetes mellitus type 2

Obesity is a chronic, non-transmissible and multifactorial disease commonly associated with systemic inflammation and damage to health. This disorder has been pointed out as leading to the development of a diversity of eye diseases and, consequently, damage to visual acuity. More specifically, cardiometabolic risk is associated with lacrimal gland dysfunctions, since it changes the inflammatory profile favoring the development and worsening of dry eye disease. In more severe and extreme cases, obesity, inflammation, and diabetes mellitus type 2 can trigger the total loss of vision. In this scenario, besides its numerous metabolic functions, clusterin, an apolipoprotein, has been described as protective to the ocular surface through the seal mechanism. Thus, the current review aimed to explain the role of clusterin in dry eye disease that can be triggered by obesity and diabetes.

Time-restricted feeding combined with aerobic exercise training can prevent weight gain and improve metabolic disorders in mice fed a high-fat diet

KEY POINTS

Time-restricted feeding (TRF, in which energy intake is restricted to 8 h/day during the dark phase) alone or combined with aerobic exercise (AE) training can prevent weight gain and metabolic disorders in Swiss mice fed a high-fat diet. The benefits of TRF combined with AE are associated with improved hepatic metabolism and decreased hepatic lipid accumulation. TRF combined with AE training increased fatty acid oxidation and decreased expression of lipogenic and gluconeogenic genes in the liver of young male Swiss mice. TRF combined with AE training attenuated the detrimental effects of high-fat diet feeding on the insulin signalling pathway in the liver.

ABSTRACT

Time-restricted feeding (TRF) or physical exercise have been shown to be efficient in the prevention and treatment of metabolic disorders; however, the additive effects of TRF combined with aerobic exercise (AE) training on liver metabolism have not been widely explored. In this study TRF (8 h in the active phase) and TRF combined with AE (TRF+Exe) were compared in male Swiss mice fed a high-fat diet, with evaluation of the effects on insulin sensitivity and expression of hepatic genes involved in fatty acid oxidation, lipogenesis and gluconeogenesis. As in previous reports, we show that TRF alone (eating only between zeitgeber time 16 and 0) was sufficient to reduce weight and adiposity gain, increase fatty acid oxidation and decrease lipogenesis genes in the liver. In addition, we show that mice of the TRF+Exe group showed additional adaptations such as increased oxygen consumption ( V ̇ O 2 ), carbon dioxide production ( V ̇ C O 2 ) and production of ketone bodies (β-hydroxybutyrate). Also, TRF+Exe attenuated the negative effects of high-fat diet feeding on the insulin signalling pathway (insulin receptor, insulin receptor substrate, Akt), and led to increased fatty acid oxidation (Ppara, Cpt1a) and decreased gluconeogenic (Fbp1, Pck1, Pgc1a) and lipogenic (Srebp1c, Cd36) gene expression in the liver. These molecular results were accompanied by increased glucose metabolism, lower serum triglycerides and reduced hepatic lipid content in the TRF+Exe group. The data presented in this study show that TRF alone has benefits but TRF+Exe has additive benefits and can mitigate the harmful effects of consuming a high-fat diet on body adiposity, liver metabolism and glycaemic homeostasis in young male Swiss mice.

Effects of short-term physical training on the interleukin-15 signalling pathway and glucose tolerance in aged rats

PURPOSE

Interleukin-15 (IL-15) is a myokine that has been proposed to modulate skeletal muscle and adipose tissue mass, as well as insulin sensitivity. However, the evidence suggesting a role for IL-15 in improving whole-body insulin sensitivity and decreasing adiposity comes mainly from studies using supraphysiological levels of this cytokine. This study examined the effect of a short-term exercise training protocol on the protein content of IL-15, it's signaling pathway, and glucose tolerance in aged rats.

METHODS

Fourteen Wistar rats were divided into Young Sedentary (Young, n = 4); Old Sedentary (Old, n = 5); Old Exercise (Old.Exe, n = 5) groups. The animals from the exercised group were submitted to a short-term physical exercise protocol for five days. At the end of physical training and after 16 h of the last exercise session, the animals were euthanized, and tissue collection was done.

RESULTS

Physical exercise decreased epididymal and mesenteric fat mass and promoted positive effects on glucose tolerance and insulin sensitivity. Muscle IL-15 protein levels were not changed following the short-term physical exercise training with no alterations in the post-exercise IL-15-JAK/STAT signaling pathway. We found a tendency to increased HIF1α and a significant increase in its regulator, PHD2, in the skeletal muscle after exercise.

CONCLUSION

The elderly rats submitted to short-term aerobic physical training did not present skeletal muscle alteration in the protein content of the IL-15 and IL-15-JAK/STAT signaling pathway. However, short-term aerobic physical training was able to modulate the expression of HIF1α and its regulator PHD2, suggesting an essential role of these proteins in improving post-exercise glucose tolerance and insulin sensitivity in elderly rats.

Physical Exercise: A Versatile Anti-Inflammatory Tool Involved in the Control of Hypothalamic Satiety Signaling

The hypothalamus plays a critical role in the control of food consumption and energy expenditure. Fatty diets can elicit an inflammatory response in specific hypothalamic cells, including astrocytes, tanycytes, and microglia, disrupting anorexigenic signals in region-specific hypothalamic neurons, contributing to overeating and body weight gain. In this study, we present an update regarding the knowledge of the effects of physical exercise on inflammatory signaling and circuits to control hunger in the hypothalamus in obesity conditions. To try to understand changes in the hypothalamus, we review the use of magnetic resonance/anorexigenic hormone analysis in humans, as well as in animal models to explore the physiological and molecular mechanism by which exercise modulates satiety signals, such as the central anti-inflammatory response, myokine delivery from skeletal muscle, and others. The accumulation of scientific evidence in recent years allows us to understand that exercise contributes to weight control, and it is managed by mechanisms that go far beyond "burning calories."

Hepatic LC3 II/I ratio is not modulated in exercised mice

Autophagy plays an essential role in body homeostasis achievement. One of the main proteins involved in this process is the LC3I, which, after lipidation, leads to the formation of LC3II that participates in the formation and maturation of autophagosome. This descriptive study verified the responses of LC3II to LC3I proteins, as well as the time-course of this ratio in mice livers after different types of acute physical exercise protocols. Eight-week-old male C57BL/6 mice were maintained three per cage with controlled temperature (22±2 °C) on a 12:12-h light-dark normal cycle with food (Purina chow) and water ad libitum. Mice were randomly divided into four groups: control (CT, sedentary mice), resistance (RE, submitted to a single bout of resistance exercise), endurance (EE, submitted to a single bout of endurance exercise), and concurrent (CE, submitted to a single bout of endurance combined with resistance exercise). The mice livers were extracted and used for the immunoblotting technique. The hepatic LC3B II/I ratio for the RE and EE groups were not altered during the different time-points. For the CE group, there was a decrease in this ratio 12h after exercise compared to time 0 and 18h. Also, the hepatic LC3B II/I ratios were not different among the acute physical exercise protocols along the time-course. The hepatic LC3B II/I ratio was not influenced by the endurance and resistance protocols but decreased in response to the concurrent protocol at 12h after the stimulus.

The Effects of Aging on Rho-Kinase and Insulin Signaling in Skeletal Muscle and White Adipose Tissue of Rats

The insulin receptor substrate 1 regulates insulin-mediated glucose uptake and is a target of Rho-kinase (Rock); however, the relationship between age-related insulin resistance and Rock signaling specifically in skeletal muscle and adipose tissue is unknown. We evaluated the content and activity of Rock in C2C12 myotubes, and in skeletal muscle and white adipose tissue (WAT) from two rodent models that differ in their patterns of body fat accumulation during aging (Wistar and Fischer 344 rats). Body fat gain in the Wistar rats was greater than in Fischer rats and only Wistar rats had impairment of whole-body insulin sensitivity. Rock activity and insulin signaling were impaired in skeletal muscle in both rat models, but only middle-aged Wistar rats had higher Rock activity in WAT. These data are consistent with a positive role of Rock in regulating insulin signaling in both skeletal muscle and its negative role in the adipose tissue, suggesting that Rock activity in adipose tissue is important in age-related insulin resistance.

Strength exercise reduces hepatic pyruvate carboxylase and gluconeogenesis in DIO mice

Obesity is linked to a reduction in the control of hepatic glucose production, which is the primary mechanism related to fasting hyperglycemia and the development of type 2 diabetes mellitus (T2DM). The main system involved in hepatic gluconeogenesis synthesis is controlled by pyruvate carboxylase (PC), which increases in obesity conditions. Recently, we showed that short-term strength training is an important tool against obesity-induced hyperglycemia. As aerobic exercise can reduce the hepatic PC content of obese animals, we hypothesized that strength exercise can also decrease this gluconeogenic enzyme. Therefore, this study investigated whether the metabolic benefits promoted by short-term strength training are related to changes in hepatic PC content. Swiss mice were divided into three groups: lean control (Ctl), obese sedentary (ObS), and obese short-term strength training (STST). The STST protocol was performed through one session/day for 15 days. The obese exercised animals had reduced hyperglycemia and insulin resistance. These results were related to better control of hepatic glucose production and hepatic insulin sensitivity. Our bioinformatics analysis showed that hepatic PC mRNA levels have positive correlations with glucose levels and adiposity, and negative correlations with locomotor activity and muscle mass. We also found that hepatic mRNA levels are related to lipogenic markers in the liver. Finally, we observed that the obese animals had an increased hepatic PC level; however, STST was efficient in reducing its amount. In conclusion, we provide insights into new biomolecular mechanisms by showing how STST is an efficient tool against obesity-related hyperglycemia and T2DM, even without body weight changes.

Physical exercise increases ROCK activity in the skeletal muscle of middle-aged rats

The physical exercise is a potential strategy to control age-related metabolic disorders, such as insulin resistance, impaired glucose homeostasis, and type 2 diabetes. Rho-kinase (ROCK) increases skeletal muscle glucose uptake through Insulin Receptor Substrate 1 (IRS1) phosphorylation. Here, we investigated the role of physical exercise in ROCK pathway in the skeletal muscle of Fischer middle-aged rats. Firstly, we observed the ROCK distribution in different skeletal muscle fiber types. ROCK signaling pathway (ROCK1 and ROCK2) and activity (pMYPT1) were higher in the soleus, which was associated with increased insulin signaling pathway (pIR, pIRS1, pPDK, pGSK3β). Middle-aged rats submitted to physical exercise, showed the upregulation of ROCK2 content and normalized RhoA (ROCK activator enzyme) levels in soleus muscle compared with middle-aged sedentary rats. These molecular changes in middle-aged exercised rats were accompanied by higher insulin signaling (pIRS1, pGSK3β, pAS160, GLUT4) in the soleus muscle. Reinforcing these findings, when pharmacological inhibition of ROCK activity was performed (using Y-27632), the insulin signaling pathway and glucose metabolism-related genes (Tpi, Pgk1, Pgam2, Eno3) were decreased in the soleus muscle of exercised rats. In summary, ROCK signaling seems to contribute with whole-body glucose homeostasis (∼50 %) through its higher upregulation in the soleus muscle in middle-aged exercised rats.

Rock protein as cardiac hypertrophy modulator in obesity and physical exercise

Obesity and cardiovascular diseases are worldwide public health issues. In this review, we discussed the participation of ROCK protein in cardiac hypertrophy, mainly through the modulation of leptin and insulin signaling pathways. Leptin plays a role in cardiovascular disease development and, through the Rho-associated protein kinase (ROCK), promotes cardiac hypertrophy. ROCK protein, is regulated by small Rho-GTPases and has two isoforms with high homology. ROCK is able to activate the MAP kinase (MAPK) pathway and modulate insulin signaling in the heart, participating in cardiac hypertrophy development of concentric and eccentric left ventricle growth. Although different types of stimulus can lead to morphologically antagonistic heart growth, physical exercise promotes improvements in hemodynamic function, emerging as a promising non-pharmacological tool to improve overall health. Leptin can activate ROCK in a pathological way, increasing MAPK activity and decreasing insulin signaling via insulin receptor substrate 1 (IRS1) serine 307 residue phosphorylation, phosphatase and tensin homolog, and protein kinase Cβ2. In turn, physical exercise decreases leptin levels and positively modulates insulin signaling as well as increases ROCK-dependent IRS1 (Ser632/635) phosphorylation, improving phosphatidylinositol 3-kinase/protein kinase B axis and promoting physiologic heart growth. Currently, there is a lack of studies about differences in ROCK isoforms, especially during exercise and/or obesity. However, the understanding of its biological function and the complex mechanism underlying the distinct types of cardiac hypertrophy development can be a useful tool in the improvement and treatment of cardiovascular outcomes.

Passion fruit peel intake decreases inflammatory response and reverts lipid peroxidation and adiposity in diet-induced obese rats

This study investigated Passiflora edulis peel flour (PEPF) intake and its effect against high-fat diet-induced obesity. PEPF is a source of fiber and phenolic compounds, which can decrease oxidative stress and inflammatory cytokines, both linked to chronic inflammatory response and fat deposition in obesity. Therefore, we hypothesized that PEPF intake could decrease inflammatory cytokines and oxidative stress observed in obesity, leading to decrease of fatness and chronic inflammatory response. The aims of the study were to evaluate the lipid peroxidation, the expression of antioxidants enzymes, and inflammatory parameters in obese rats. Male Sprague-Dawley rats were divided into 3 groups (n = 8 per group) according to the diets: control (based on AIN-93G), high-fat (HF, 35% fat w/w), and HF with PEPF (HFPF), and the experiment lasted for 10 weeks. PEPF showed high dietary fiber content and bioactive compounds, such as ferulic acid, and β-carotene. PEPF intake was effective in reducing body weight gain (13.31%) and total body fat (22.58%). The lipid peroxidation in the liver and adipose tissue decreased in the HFPF group compared to HF-fed animals, whereas hepatic glutathione peroxidase and glutathione reductase activity and their expressions in the liver were higher in HFPF than HF. In addition, the PEPF intake decreased inflammatory cytokines in serum. These results suggest that PEPF intake decreases oxidative stress, possibly by the increase of antioxidant enzymes expression. Furthermore, PEPF decreases inflammatory response and protects from adiposity. Then, PEPF could act as an adjuvant to control of early parameters in obesity dysfunction.

Short-term high-fat diet modulates several inflammatory, ER stress, and apoptosis markers in the hippocampus of young mice

The consumption of saturated fatty acids is one of the leading risk factors for Alzheimer's Disease (AD) development. Indeed, the short-term consumption of a high-fat diet (HFD) is related to increased inflammatory signals in the hippocampus; however, the potential molecular mechanisms linking it to AD pathogenesis are not fully elucidated. In our study, we investigated the effects of short-term HFD feeding (within 3, 7 and 10 days) in AD markers and neuroinflammation in the hippocampus of mice. The short period of HFD increased fasting glucose and HOMA-IR. Also, mice fed HFD increased the protein content of β-Amyloid, pTau, TNFα, IL1β, pJNK, PTP1B, peIF2α, CHOP, Caspase3, Cleaved-Caspase3 and Alzheimer-related genes (Bax, PS1, PEN2, Aph1b). At 10 days, both neuronal (N2a) and microglial (BV2) cells presented higher expression of inflammatory and apoptotic genes when stimulated with palmitate. These findings suggest that a short period of consumption of a diet rich in saturated fat is associated with activation of inflammatory, ER stress and apoptotic signals in the hippocampus of young mice.

Short-term Resistance Training Increases APPL1 Content in the Liver and the Insulin Sensitivity of Mice Fed a Long-term High-fat Diet

Background APPL1, an adapter protein, interact directly with adiponectin receptors mediating adiponectin signaling and acting as a critical regulator of the crosstalk between adiponectin and insulin signaling pathway. The inadequate level of physical activity, high-calorie intake, or both lead to adverse consequences on health, like insulin resistance. On the order hand, physical exercise acts positively in the insulin action.

Purpose Here, we investigated the effects of short-term resistance training (RT) on APPL1 content and adiponectin pathway in the liver of mice fed a long-term high-fat diet.

Methods Swiss mice were distributed into 3 groups: Mice that fed a chow diet (CTR); Mice fed a high-fat diet for 16 months (HFD); and mice fed a high-fat diet for 16 months and submitted to a climbing ladder exercise (RT) for 7 days (HFD-EXE).

Results The results show that short-term RT increases the APPL1 content but wasn’t able to alter AdipoR1 and AdipoR2 content in the liver of HFD-EXE mice. However, this increase in the APPL1 content in response to RT was accompanied by improvement in the insulin sensitivity.

Conclusion In summary, our data suggested that short-term RT improves glycemic homeostasis and increases APPL1 in the hepatic tissue of mice treated with long-term high-fat diet.

Short-term strength training reduces gluconeogenesis and NAFLD in obese mice

Non-alcoholic fatty liver disease (NAFLD) has a positive correlation with obesity, insulin resistance and type 2 diabetes mellitus (T2D). The aerobic training is an important tool in combating NAFLD. However, no studies have demonstrated the molecular effects of short-term strength training on the accumulation of hepatic fat in obese mice. This study aimed to investigate the effects of short-term strength training on the mechanisms of oxidation and lipid synthesis in the liver of obese mice. The short duration protocol was used to avoid changing the amount of adipose tissue. Swiss mice were separated into three groups: lean control (CTL), sedentary obese (OB) and strength training obese (STO). The obese groups were fed a high-fat diet (HFD) and the STO group performed the strength training protocol 1 session/day for 15 days. The short-term strength training reduced hepatic fat accumulation, increasing hepatic insulin sensitivity and controlling hepatic glucose production. The obese animals increased the mRNA of lipogenic genes Fasn and Scd1 and reduced the oxidative genes Cpt1a and Ppara. On the other hand, the STO group presented the opposite results. Finally, the obese animals presented higher levels of lipogenic proteins (ACC and FAS) and proinflammatory cytokines (TNF-α and IL-1β), but the short-term strength training was efficient in reducing this condition, regardless of body weight loss. In conclusion, there was a reduction of obesity-related hepatic lipogenesis and inflammation after short-term strength training, independent of weight loss, leading to improvements in hepatic insulin sensitivity and glycemic homeostasis in obese mice. Key points: (1) Short-term strength training (STST) reduced fat accumulation and inflammation in the liver; (2) Hepatic insulin sensitivity and HPG control were increased with STST; (3) The content and activity of ACC and content of FAS were reduced with STST; (4) STST improved hepatic fat accumulation and glycemic homeostasis; (5) STST effects were observed independently of body weight change.

Interesterified Fats Induce Deleterious Effects on Adipose Tissue and Liver in LDLr-KO Mice

Interesterified fats are being widely used by the food industry in an attempt to replace trans fatty acids. The effect of interesterified fats containing palmitic or stearic acids on lipid metabolism and inflammatory signaling pathways in adipose and hepatic tissues was evaluated. Male LDLr-KO mice were fed a high-fat diet containing polyunsaturated (PUFA), palmitic (PALM), palmitic interesterified (PALM INTER), stearic (STEAR), or stearic interesterified (STEAR INTER) fats for 16 weeks. The expression of genes and protein levels involved in lipid metabolism and inflammatory processes in liver and white adipose tissue was determined by quantitative RT-PCR and by Western blot, respectively. The infiltration of inflammatory cells in hepatic and adipose tissues was determined by eosin and hematoxylin, while liver collagen content was determined by Sirius Red staining. Both interesterified fats increased liver collagen content and JNK phosphorylation. Additionally, the STEAR INTER group developed nonalcoholic steatohepatitis (NASH) associated with higher neutrophil infiltration. PALM INTER induced adipose tissue expansion and enlargement of adipocytes. Furthermore, PALM INTER triggered increased IKK phosphorylation and TNFα protein content, conditions associated with the upstream activation of the NFkB signaling pathway. STEAR INTER induced NASH, while PALM INTER triggered hepatic fibrosis and adipocyte hypertrophy with inflammatory response in LDLr-KO mice.

Protective molecular mechanisms of clusterin against apoptosis in cardiomyocytes

Loss of cardiomyocytes occurs with aging and contributes to cardiovascular complications. In the present study, we highlighted the role of clusterin, a protein that has recently been associated with the protection of cardiomyocytes from apoptosis. Clusterin protects cardiac cells against damage from myocardial infarction, transplant, or myocarditis. Clusterin can act directly or indirectly on apoptosis by regulating several intracellular pathways. These pathways include (1) the oxidant and inflammatory program, (2) insulin growth factor 1 (IGF-1) pathway, (3) KU70 / BCL-2-associated X protein (BAX) pathway, (4) tumor necrosis factor alpha (TNF-α) pathway, (5) BCL-2 antagonist of cell death (BAD) pathway, and (6) mitogen-activated protein kinase (MAPK) pathway. Given the key role of clusterin in preventing loss of cardiac tissue, modulating the expression and function of this protein carries the potential of improving cardiovascular care in the future.

Omega-3 from Flaxseed Oil Protects Obese Mice Against Diabetic Retinopathy Through GPR120 Receptor

The chronic and low-grade inflammation induced by obesity seem to be the “first hit” to retinopathy associated to diabetes type 2. Herein, we hypothesized that omega-3 fatty acids from flaxseed oil enriched diet disrupt the pro-inflammatory status in the retina, protecting against retinopathy development. For eight weeks under a high-fat diet (HF), several physiological parameters were monitored to follow the metabolic homeostasis disruption. After this period, mice were treated with a HF substituted in part of lard by flaxseed oil (FS) for another eight weeks. Food behavior, weight gain, glucose and insulin sensitivity, electroretinography, RT-qPCR and western blots were carried out. The HF was able to induce a pro-inflammatory background in the retina, changing IL1β and TNFα. VEGF, a master piece of retinopathy, had early onset increased also induced by HF. The FS-diet was able to decrease inflammation and retinopathy and improved retinal electro stimuli compared to HF group. GPR120 and GPR40 (G Protein-Coupled Receptors 120 and 40), an omega-3 fatty acid receptors, were detected in the retina for the first time. FS-diet modulated the gene expression and protein content of these receptors. Thus, unsaturated fatty acids protect the retina from diabetes type 2 mice model from disease progression.

Acute physical exercise increases leptin-induced hypothalamic extracellular signal-regulated kinase1/2 phosphorylation and thermogenesis of obese mice

The obesity is a result of energy imbalance and the increase in thermogenesis seems an interesting alternative for the treatment of this disease. The mechanism of energy expenditure through thermogenesis is tightly articulated in the hypothalamus by leptin. The hypothalamic extracellular signal-regulated kinase-1/2 (ERK1/2) is a key mediator of the thermoregulatory effect of leptin and mediates the sympathetic signal to the brown adipose tissue (BAT). In this context, physical exercise is one of the main interventions for the treatment of obesity. Thus, this study aimed to verify the effects of acute physical exercise on leptin-induced hypothalamic ERK1/2 phosphorylation and thermogenesis in obese mice. Here we showed that acute physical exercise reduced the fasting glucose of obese mice and increased leptin-induced hypothalamic p-ERK1/2 and uncoupling protein 1 (UCP1) content in BAT ( P < 0.05). These molecular changes are accompanied by an increased oxygen uptake (VO ₂ ) and heat production in obese exercised mice ( P < 0.05). The increased energy expenditure in the obese exercised animals occurred independently of changes in spontaneous activity. Thus, this is the first study demonstrating that acute physical exercise can increase leptin-induced hypothalamic ERK1/2 phosphorylation and energy expenditure of obese mice.

The reversal effect of physical exercise on aging-related increases in APPL2 content in skeletal muscle

AIMS

The aim of this study was to evaluate the effects of aging on intracellular adiponectin signaling and the possible therapeutic effect of physical exercise.

MAIN METHODS

Fischer 344 rats were distributed in the following groups: Young (3 months old); Sedentary Old (Old, 27 months old); and Old Exercised (Old-Exe, 27 months old), which were subjected to a short-term exercise training protocol.

KEY FINDINGS

The results showed that the old rats presented glucose intolerance without increased adiposity. However, short-term exercise training reversed this disorder, which was associated with a decrease in the pleckstrin homology domain, phosphotyrosine-binding domain, and leucine zipper motif (APPL) isoform 2 (APPL2) content. The APPL isoform 1 (APPL1) and TRB3 (Tribbles homolog 3) contents were not altered. Akt phosphorylation was only increased in the old exercised rats. There was a reduction in the content of adiponectin receptor 1 in the old rats.

SIGNIFICANCE

The short-term exercise training protocol was able to decrease APPL2 content in the skeletal muscle, which was accompanied by an improvement in the glucose tolerance of the old Fischer 344 rats. These findings provide new evidence supporting the role of physical exercise as a non-pharmacological therapeutic intervention to attenuate age-related deficits.

Physical exercise reduces pyruvate carboxylase (PCB) and contributes to hyperglycemia reduction in obese mice

The present study evaluated the effects of exercise training on pyruvate carboxylase protein (PCB) levels in hepatic tissue and glucose homeostasis control in obese mice. Swiss mice were distributed into three groups: control mice (CTL), fed a standard rodent chow; diet-induced obesity (DIO), fed an obesity-inducing diet; and a third group, which also received an obesity-inducing diet, but was subjected to an exercise training protocol (DIO + EXE). Protocol training was carried out for 1 h/d, 5 d/wk, for 8 weeks, performed at an intensity of 60% of exhaustion velocity. An insulin tolerance test (ITT) was performed in the last experimental week. Twenty-four hours after the last physical exercise session, the animals were euthanized and the liver was harvested for molecular analysis. Firstly, DIO mice showed increased epididymal fat and serum glucose and these results were accompanied by increased PCB and decreased p-Akt in hepatic tissue. On the other hand, physical exercise was able to increase the performance of the mice and attenuate PCB levels and hyperglycemia in DIO + EXE mice. The above findings show that physical exercise seems to be able to regulate hyperglycemia in obese mice, suggesting the participation of PCB, which was enhanced in the obese condition and attenuated after a treadmill running protocol. This is the first study to be aimed at the role of exercise training in hepatic PCB levels, which may be a novel mechanism that can collaborate to reduce the development of hyperglycemia and type 2 diabetes in DIO mice.

Impaired insulin signaling and spatial learning in middle-aged rats: The role of PTP1B

The insulin and Brain-Derived Neurotrophic Factor (BDNF) signaling in the hippocampus promotes synaptic plasticity and memory formation. On the other hand, aging is related to the cognitive decline and is the main risk factor for Alzheimer's Disease (AD). The Protein-Tyrosine Phosphatase 1B (PTP1B) is related to several deleterious processes in neurons and emerges as a promising target for new therapies. In this context, our study aims to investigate the age-related changes in PTP1B content, insulin signaling, β-amyloid content, and Tau phosphorylation in the hippocampus of middle-aged rats. Young (3 months) and middle-aged (17 months) Wistar rats were submitted to Morris-water maze (MWM) test, insulin tolerance test, and molecular analysis in the hippocampus. Aging resulted in increased body weight, and insulin resistance and decreases learning process in MWM. Interestingly, the middle-aged rats have higher levels of PTP-1B, lower phosphorylation of IRS-1, Akt, GSK3β, mTOR, and TrkB. Also, the aging process increased Tau phosphorylation and β-amyloid content in the hippocampus region. In summary, this study provides new evidence that aging-related PTP1B increasing, contributing to insulin resistance and the onset of the AD.

Hypothalamic S1P/S1PR1 axis controls energy homeostasis in Middle-Aged Rodents: the reversal effects of physical exercise

Recently, we demonstrated that the hypothalamic S1PR1/STAT3 axis plays a critical role in the control of food consumption and energy expenditure in rodents. Here, we found that reduction of hypothalamic S1PR1 expression occurs in an age-dependent manner, and was associated with defective thermogenic signaling and weight gain. To address the physiological relevance of these findings, we investigated the effects of chronic and acute exercise on the hypothalamic S1PR1/STAT3 axis. Chronic exercise increased S1PR1 expression and STAT3 phosphorylation in the hypothalamus, restoring the anorexigenic and thermogenic signals in middle-aged mice. Acutely, exercise increased sphingosine-1-phosphate (S1P) levels in the cerebrospinal fluid (CSF) of young rats, whereas the administration of CSF from exercised young rats into the hypothalamus of middle-aged rats at rest was sufficient to reduce the food intake. Finally, the intracerebroventricular (ICV) administration of S1PR1 activators, including the bioactive lipid molecule S1P, and pharmacological S1PR1 activator, SEW2871, induced a potent STAT3 phosphorylation and anorexigenic response in middle-aged rats. Overall, these results suggest that hypothalamic S1PR1 is important for the maintenance of energy balance and provide new insights into the mechanism by which exercise controls the anorexigenic and thermogenic signals in the central nervous system during the aging process.

Overexpression of Mitogen-activated protein kinase phosphatase-3 (MKP-3) reduces FoxO1 phosphorylation in mice hypothalamus

The mitogen-activated kinase phosphatase-3 (MKP-3) has gained great importance in the scientific community by acting as a regulator of the cell cycle through dephosphorylation of FoxO1, an important transcription factor involved in the insulin intracellular signaling cascade. When dephosphorylated and translocated to the nuclei, FoxO1 can promote the transcription of orexigenic neuropeptides (NPY/AgRP) in the hypothalamus, whereas insulin signaling is responsible for the disruption of this process. However, it is not understood if the hypothalamic activation of MKP-3 affects FoxO1 phosphorylation, and we hypothesized that MKP-3 overexpression reduces the capacity of the insulin signal to phosphorylate FoxO1. In the present study, we overexpressed the DUSP6 gene through an injection of adenovirus directly into the hypothalamic third ventricle of Swiss mice. The colocalization of the adenovirus was confirmed by the immunofluorescence assay. Then, MKP-3 overexpression resulted in a significant reduction of hypothalamic FoxO1 phosphorylation after insulin stimulation. This effect was independent of changes in Akt phosphorylation. Thus, the role of MKP-3 in the hypothalamus is closely associated with FoxO1 dephosphorylation and may provide a potential therapeutic target against hypothalamic disorders related to obesity and unbalanced food intake control.