Metabolic Health In Mice Research Articles

Abstract P488: Diet Significantly Alters Metabolic Gene Expression Associated With Probiotic Administration in Mice

The microbial flora in the gastrointestinal tract is known to be mediated by diet and is thus one potential mechanism by which diet influences health. Furthermore, probiotic supplementation also affects various biological markers, however it is unclear if a diet and probiotic interaction exists. Therefore, the goal of our study was to assess how diet and probiotic administration influenced metabolic health in mice. Weanling, male C57Bl/6 mice were randomly assigned to receive one of three diets: chow, American Institute of Nutrition 93 formulation (AIN93), or our novel Americanized diet (AD) formulated to match the 50 th percentile of nutrient intake in Americans. Mice were then administered a commercially-available probiotic for 2-weeks and then euthanized. Insulin sensitivity was determined by performing an insulin-tolerance test (ITT) in a separate cohort. Blood was collected for serum analysis of circulating metabolic markers. Liver and adipose tissue were collected and processed to quantify the mRNA expression of key metabolic genes by real-time RT-PCR. All data were analyzed using General Linear Model Procedures in SPSS with significance determined at P<0.05. Diet (P=0.001), but not probiotic supplementation (P=0.27), significantly affected ITT with the AD group having the lowest responsiveness to insulin ( P ≤0.001). Chow fed mice tended ( P =0.09) to have lower HDL than the AIN-93 and AD fed mice. Probiotic administration alone resulted in an upregulation of liver mRNA expression of SREBF2, particularly the AIN-93 diet group (P=0.024). Probiotic supplementation also modulated liver transcription of NF-κB1 with an increase in chow-fed mice, but decreased in those fed AD (P=0.016). Increased transcription of the key carbohydrate metabolism regulating gene, Mlxipl , was found to occur in liver of the chow and AIN-93 and also tended to differ in mice fed the AD (P=0.06). In the adipose tissue, diet (P<0.001), probiotic (P<0.001), and their interaction (P=0.01) influenced transcription of the androgen receptor ( Ar ) gene. The chow group had the most Ar transcription, while the AD had the lowest transcription in both the diet alone and probiotic treated group. Taken together, our data highlight the significance of diet in mediating the beneficial metabolic effects of probiotic administration. Diet appears to play a greater role in dictating the expression of key metabolic enzymes and transcription factors and future studies are needed to validate these findings and determine their physiological significance.

Exploring the health-promoting potential: Dietary intervention with live or inactivated Lactobacillus gasseri HM1 probiotics in obese mice

BackgroundThis study explores the impact of dietary interventions with live or inactivated Lactobacillus gasseri HM1 probiotics on metabolic health in mice. MethodsAfter inducing obesity in 24 mice with a high-fat diet, they transitioned to a standard chow diet (SCD) while receiving a daily oral placebo, live HM1, heat-killed HM1 (HK-HM1), or sonication-killed HM1 (SK-HM1) for 6 weeks. ResultsResults indicate that SCD with live HM1 significantly improved triglyceride levels, glucose tolerance, and insulin sensitivity. SK-HM1 improved perirenal fat inflammation and reduced serum leptin concentration, while HK-HM1 showed improvements in inflammation in fat tissues and reduced serum IL-6, leptin, and catalase protein levels. Both HK-HM1 and SK-HM1 reduced colon IL-6, TGF-β1, and IL-1β cytokine levels, with HK-HM1 having the most significant effect. ConclusionsThese findings underscore the potential of dietary interventions with HM1 probiotics to enhance metabolic health, revealing distinct benefits between live and inactivated forms.

#208 : The Adverse Effects of Vitrification on Embryo Development and Metabolic Health in Mice Offspring

Background and Aims: Embryo vitrification is widely applied as a routine procedure of assisted reproductive technology. Cohort studies showed frozen embryo transfer (FET) was associated with an elevated risk of adverse maternal and neonatal outcomes compared with fresh embryo transfer. This study aimed to explore the effects of blastocyst vitrification on embryo development and long-term metabolic health in mice. Method: Mitochondrial function, apoptotic levels and cell numbers were examined in blastocysts with/without vitrification. Implantation rates, fetal growth and placentation were analysed after fresh and frozen blastocyst transfer. Energy consumptions were measured by indirect calorimetry. Metabolic tests were performed in adult mice offspring, including glucose tolerance, insulin tolerance and pyruvate tolerance. Serum lipid profiles were examined, and fetal and adult hepatic transcriptome status were detected by RNA-sequencing and qRT-PCR. Results: Mitochondrial dysfunction increased apoptotic levels and decreased cell numbers were observed in vitrified blastocysts. The implantation and live pup rates on embryonic day18.5 were not significantly different between the fresh and frozen groups. However, fetal weights and placental efficiencies such as the ratio of labyrinth layer/ junctional zone and microvascular density were significantly reduced after FET. Offspring aged 36 weeks in the FET group had decreased whole energy consumption, impaired glucose and pyruvate tolerance, insulin resistance, higher serum triglyceride, low-density lipoprotein and total cholesterol levels compared with the fresh group. However, these metabolic effects were not observed in mice offspring aged 14 weeks. The FET group also had altered hepatic gene expression and signaling pathways related to metabolic regulation, apoptotic cell clearance, and regulation of response to reactive oxygen species etc. Conclusion: The data indicated that blastocyst vitrification has short-term and long-term adverse effects in the mouse model. Further studies are needed to optimize vitrification procedure.

Differential expression of immunoregulatory cytokines in adipose tissue and liver in response to high fat and high sugar diets in female mice.

A comprehensive understanding of how dietary components impact immunoregulatory gene expression in adipose tissue (AT) and liver, and their respective contributions to metabolic health in mice, remains limited. The current study aimed to investigate the metabolic consequences of a high-sucrose diet (HSD) and a high-fat diet (HFD) in female mice with a focus on differential lipid- and sucrose-induced changes in immunoregulatory gene expression in AT and liver. Female C57BL/6 J mice were fed a purified and macronutrient matched high fat, high sugar, or control diets for 12 weeks. Mice were extensively phenotyped, including glucose and insulin tolerance tests, adipose and liver gene and protein expression analysis by qPCR and Western blot, tissue lipid analyses, as well as histological analyses. Compared to the control diet, HSD- and HFD-fed mice had significantly higher body weights, with pronounced obesity along with glucose intolerance and insulin resistance only in HFD-fed mice. HSD-fed mice exhibited an intermediate phenotype, with mild metabolic deterioration at the end of the study. AT lipid composition was significantly altered by both diets, and inflammatory gene expression was only significantly induced in HFD-fed mice. In the liver however, histological analysis revealed that both HSD- and HFD-fed mice had pronounced ectopic lipid deposition indicating hepatic steatosis, but more pronounced in HSD-fed mice. This was in line with significant induction of pro-inflammatory gene expression specifically in livers of HSD-fed mice. Overall, our findings suggest that HFD consumption in female mice induces more profound inflammation in AT with pronounced deterioration of metabolic health, whereas HSD induced more pronounced hepatic steatosis and inflammation without yet affecting glucose metabolism.

Lung versus gut exposure to air pollution particles differentially affect metabolic health in mice

BackgroundAir pollution has emerged as an unexpected risk factor for diabetes. However, the mechanism behind remains ill-defined. So far, the lung has been considered as the main target organ of air pollution. In contrast, the gut has received little scientific attention. Since air pollution particles can reach the gut after mucociliary clearance from the lungs and through contaminated food, our aim was to assess whether exposure deposition of air pollution particles in the lung or the gut drive metabolic dysfunction in mice.MethodsTo study the effects of gut versus lung exposure, we exposed mice on standard diet to diesel exhaust particles (DEP; NIST 1650b), particulate matter (PM; NIST 1649b) or phosphate-buffered saline by either intratracheal instillation (30 µg 2 days/week) or gavage (12 µg 5 days/week) over at least 3 months (total dose of 60 µg/week for both administration routes, equivalent to a daily inhalation exposure in humans of 160 µg/m3 PM2.5) and monitored metabolic parameters and tissue changes. Additionally, we tested the impact of the exposure route in a “prestressed” condition (high-fat diet (HFD) and streptozotocin (STZ)).ResultsMice on standard diet exposed to particulate air pollutants by intratracheal instillation developed lung inflammation. While both lung and gut exposure resulted in increased liver lipids, glucose intolerance and impaired insulin secretion was only observed in mice exposed to particles by gavage. Gavage with DEP created an inflammatory milieu in the gut as shown by up-regulated gene expression of pro-inflammatory cytokines and monocyte/macrophage markers. In contrast, liver and adipose inflammation markers were not increased. Beta-cell secretory capacity was impaired on a functional level, most likely induced by the inflammatory milieu in the gut, and not due to beta-cell loss. The differential metabolic effects of lung and gut exposures were confirmed in a “prestressed” HFD/STZ model.ConclusionsWe conclude that separate lung and gut exposures to air pollution particles lead to distinct metabolic outcomes in mice. Both exposure routes elevate liver lipids, while gut exposure to particulate air pollutants specifically impairs beta-cell secretory capacity, potentially instigated by an inflammatory milieu in the gut.

Impact of selenium on the intestinal microbiome-eCBome axis in the context of diet-related metabolic health in mice.

Dietary micronutrients act at the intestinal level, thereby influencing microbial communities, the host endocannabinoidome, and immune and anti-oxidative response. Selenium (Se) is a trace element with several health benefits. Indeed, Se plays an important role in the regulation of enzymes with antioxidative and anti-inflammatory activity as well as indicators of the level of oxidative stress, which, together with chronic low-grade inflammation, is associated to obesity. To understand how Se variations affect diet-related metabolic health, we fed female and male mice for 28 days with Se-depleted or Se-enriched diets combined with low- and high-fat/sucrose diets. We quantified the plasma and intestinal endocannabinoidome, profiled the gut microbiota, and measured intestinal gene expression related to the immune and the antioxidant responses in the intestinal microenvironment. Overall, we show that intestinal segment-specific microbiota alterations occur following high-fat or low-fat diets enriched or depleted in Se, concomitantly with modifications of circulating endocannabinoidome mediators and changes in cytokine and antioxidant enzyme expression. Specifically, Se enrichment was associated with increased circulating plasma levels of 2-docosahexaenoyl-glycerol (2-DHG), a mediator with putative beneficial actions on metabolism and inflammation. Others eCBome mediators also responded to the diets. Concomitantly, changes in gut microbiota were observed in Se-enriched diets following a high-fat diet, including an increase in the relative abundance of Peptostreptococcaceae and Lactobacillaceae. With respect to the intestinal immune response and anti-oxidative gene expression, we observed a decrease in the expression of proinflammatory genes Il1β and Tnfα in high-fat Se-enriched diets in caecum, while in ileum an increase in the expression levels of the antioxidant gene Gpx4 was observed following Se depletion. The sex of the animal influenced the response to the diet of both the gut microbiota and endocannabinoid mediators. These results identify Se as a regulator of the gut microbiome and endocannabinoidome in conjunction with high-fat diet, and might be relevant to the development of new nutritional strategies to improve metabolic health and chronic low-grade inflammation associated to metabolic disorders.

Effect of Combined In-Utero and Lifelong Exposure to Dietary Sugars on Offspring Metabolic Health in Mice

ObjectivesCarbohydrates are the most abundant macronutrient in the diet, their quality is paramount to good metabolic health. The glycaemic index (GI) measures carbohydrate quality based on postprandial blood glucose levels, with lower GI foods associated with better metabolic health. This study compared sugars with a range of GIs from glucose (highest), sucrose (middle) and isomaltulose (lowest). MethodsC57BL/6J female mice were fed one of three isocaloric sugar diets or an AIN93-G control and mated with chow males. Pups continued their mother’s diet until 30-weeks. Body composition was determined by EchoMRI, feeding behaviour by BioDAQ and oral glucose tolerance tests (OGTT) performed. ResultsFemale pups fed sugar diets were fatter by 30-weeks compared to controls. In male mice, glucose-fed pups were heavier, and all sugar-fed pups were fatter compared to controls. Female sugar pups secreted more insulin in response to glucose and insulin peak was delayed in mice fed isomaltulose. At both 12- and 24-weeks, sugar fed mice ate for shorter periods of time (AIN93-G vs glucose p < 0.01; vs sucrose p < 0.05; vs isomatulose p < 0.001) compared to AIN93-G mice but ate more frequently (AIN93-G vs glucose p < 0.05; vs sucrose p < 0.001; vs isomatulose p < 0.001) and had increased food intake over 24 hours (AIN93-G vs sucrose p < 0.05; vs isomatulose p < 0.05). Interestingly, at 24-weeks food intake was reduced, compared to 12-weeks in sugar-fed mice. These results may be due to the increased presence of liver fibrosis observed in 32% of glucose-, 38% of sucrose- and 24% of isomaltulose-fed mice and corroborated with histology. At 30-weeks AIN93-G mice had larger caecum’s than their sugar-fed counterparts frequently (AIN93-G vs glucose p < 0.05; vs sucrose p < 0.01; vs isomatulose p < 0.05). ConclusionsThese results suggest female mice are more heavily affected at 30-weeks across all sugar diets with a higher body weight, percent fat, insulin response to an OGTT, increased food intake, liver fibrosis and caecum weight. Male mice show less differences in weight but sugar still negatively effects body composition, food intake, liver fibrosis and caecum weight. These findings show that free sugars, regardless of their GI can induce changes in body composition and risk of metabolic disease. Funding SourcesThe University of Sydney.

Moringa Oleifera Seed Extract Concomitantly Supplemented with Chemotherapy Worsens Tumor Progression in Mice with Triple Negative Breast Cancer and Obesity

Triple negative breast cancer (TNBC) is an aggressive and highly metastatic breast cancer subtype with limited treatment options. Obesity and insulin resistance are associated with a worse prognosis in those with TNBC. Moringa oleifera (moringa) is a tropical edible plant used for both food and medicinal purposes and found to have anti-obesity and anti-cancer effects in vitro and in preclinical models. The anti-cancer effects of moringa seed extract alone and in combination with chemotherapy were evaluated in immunocompromised female mice with diet-induced obesity bearing MDA-MB-231-derived xenograft tumors. Moringa supplementation protected against high-fat diet- and chemotherapy-induced increases in fasting glucose and improved insulin sensitivity. Moringa supplementation alone did not attenuate tumor growth relative to chemotherapy alone, and in combination worsened tumor progression. Moringa supplementation alone reduced angiogenesis, but this effect was abrogated in combination with chemotherapy. Moringa supplementation may be an effective strategy to improve metabolic health in mice with obesity and TNBC and reduce angiogenesis in tumors, but may have a negative interaction when used as a concurrent complementary therapy. Caution should be taken when considering the consumption of moringa seed extracts while receiving chemotherapy for breast cancer treatment. Further investigations of alternative timings of moringa therapy are warranted.

Physiologic Responses to Dietary Sulfur Amino Acid Restriction in Mice Are Influenced by Atf4 Status and Biological Sex

ABSTRACTBackgroundDietary sulfur amino acid restriction (SAAR) improves body composition and metabolic health across several model organisms in part through induction of the integrated stress response (ISR).ObjectiveWe investigate the hypothesis that activating transcription factor 4 (ATF4) acts as a converging point in the ISR during SAAR.MethodsUsing liver-specific or global gene ablation strategies, in both female and male mice, we address the role of ATF4 during dietary SAAR.ResultsWe show that ATF4 is dispensable in the chronic induction of the hepatokine fibroblast growth factor 21 while being essential for the sustained production of endogenous hydrogen sulfide. We also affirm that biological sex, independent of ATF4 status, is a determinant of the response to dietary SAAR.ConclusionsOur results suggest that auxiliary components of the ISR, which are independent of ATF4, are critical for SAAR-mediated improvements in metabolic health in mice.

TFEB deficiency attenuates mitochondrial degradation upon brown adipose tissue whitening at thermoneutrality

ObjectiveBrown adipose tissue (BAT) thermogenesis offers the potential to improve metabolic health in mice and humans. However, humans predominantly live under thermoneutral conditions, leading to BAT whitening, a reduction in BAT mitochondrial content and metabolic activity. Recent studies have established mitophagy as a major driver of mitochondrial degradation in the whitening of thermogenic brite/beige adipocytes, yet the pathways mediating mitochondrial breakdown in whitening of classical BAT remain largely elusive. The transcription factor EB (TFEB), a master regulator of lysosomal biogenesis and autophagy belonging to the MiT family of transcription factors, is the only member of this family that is upregulated during whitening, pointing toward a role of TFEB in whitening-associated mitochondrial breakdown. MethodsWe generated brown adipocyte-specific TFEB knockout mice, and induced BAT whitening by thermoneutral housing. We characterized gene and protein expression patterns, BAT metabolic activity, systemic metabolism, and mitochondrial localization using in vivo and in vitro approaches. ResultsUnder low thermogenic activation conditions, deletion of TFEB preserves mitochondrial mass independently of mitochondriogenesis in BAT and primary brown adipocytes. However, this does not translate into elevated thermogenic capacity or protection from diet-induced obesity. Autophagosomal/lysosomal marker levels are altered in TFEB-deficient BAT and primary adipocytes, and lysosomal markers co-localize and co-purify with mitochondria in TFEB-deficient BAT, indicating trapping of mitochondria in late stages of mitophagy. ConclusionWe identify TFEB as a driver of BAT whitening, mediating mitochondrial degradation via the autophagosomal and lysosomal machinery.This study provides proof of concept that interfering with the mitochondrial degradation machinery can increase mitochondrial mass in classical BAT under human-relevant conditions. However, it must be considered that interfering with autophagy may result in accumulation of non-functional mitochondria. Future studies targeting earlier steps of mitophagy or target recognition are therefore warranted.

Systems toxicogenomics of prenatal low-dose BPA exposure on liver metabolic pathways, gut microbiota, and metabolic health in mice

Bisphenol A (BPA) is an industrial plasticizer widely found in consumer products, and exposure to BPA during early development has been associated with the prevalence of various cardiometabolic diseases including obesity, metabolic syndrome, type 2 diabetes, and cardiovascular diseases. To elucidate the molecular perturbations underlying the connection of low-dose prenatal BPA exposure to cardiometabolic diseases, we conducted a multi-dimensional systems biology study assessing the liver transcriptome, gut microbial community, and diverse metabolic phenotypes in both male and female mouse offspring exposed to 5 μg/kg/day BPA during gestation. Prenatal exposure to low-dose BPA not only significantly affected liver genes involved in oxidative phosphorylation, PPAR signaling and fatty acid metabolism, but also affected the gut microbial composition in an age- and sex-dependent manner. Bacteria such as those belonging to the S24-7 and Lachnospiraceae families were correlated with offspring phenotypes, differentially expressed liver metabolic genes such as Acadl and Dgat1, and key drivers identified in our gene network modeling such as Malat1 and Apoa2. This multiomics study provides insight into the relationship between gut bacteria and host liver genes that could contribute to cardiometabolic disease risks upon low-dose BPA exposure.

Replacing smoking with vaping during pregnancy: Impacts on metabolic health in mice

Smoking is a significant risk factor for the development of metabolic diseases. Due to social pressures to quit smoking, many pregnant women are vaping as an alternative nicotine source. However, the metabolic consequences of replacing tobacco cigarettes with e-cigarettes during pregnancy are unknown. Therefore, in the mothers and their offspring, we investigated the metabolic and hepatic impacts of replacing cigarette smoke with e-vapour during pregnancy. Female BALB/c mice were either air-exposed or cigarette smoke-exposed (SE) from six weeks before pregnancy until lactation. At mating, a subset of the SE mice were instead exposed to e-vapour. Markers of glucose and lipid metabolism were measured in the livers and plasma, from the mothers and their male offspring (13 weeks). In the SE mothers, plasma insulin levels were reduced, leading to downstream increases in hepatic gluconeogenesis and plasma non-esterified fatty acids (NEFA). In the e-vapour replacement mothers, these changes were not as significant. In the SE offspring, there was impaired glucose tolerance, and increased plasma NEFA and liver triglyceride concentrations. E-vapour replacement restored lipid homeostasis but did not improve glucose tolerance. Therefore, in a murine model, low dose e-cigarette replacement during pregnancy is less toxic than cigarette smoke.

Differential Responses of White Adipose Tissue and Brown Adipose Tissue to Calorie Restriction During Aging.

Age-related adipose tissue dysfunction is potentially important in the development of insulin resistance and metabolic disorder. Caloric restriction (CR) is a robust intervention to reduce adiposity, improve metabolic health, and extend healthy life span. Both white adipose tissue (WAT) and brown adipose tissue (BAT) are involved in energy homeostasis. CR triggers the beiging of WAT in young mice; however, the effects of CR on beiging of WAT and function of BAT during aging are unclear. This study aimed to investigate how age and CR impact the beiging of WAT, the function of BAT, and metabolic health in mice. C57BL/6 mice were fed CR diet (40% less than the ad libitum [AL] diet) for 3 months initiated in young (3 months), middle-aged (12 months), and old (19 months) stage. We found age-related changes in different types of adipose tissue, including adipocyte enlargement, declined beiging of WAT, and declined thermogenic and β-oxidational function of BAT. Moreover, CR attenuated age-associated adipocyte enlargement and prevented the age-related decline in beiging potential of WAT. These protective effects on the beiging potential were significant in inguinal WAT at all three ages, which were significant in epididymal WAT at young and old age. In contrast, thermogenic and β-oxidational function of BAT further declined after CR in the young age group. In conclusion, our findings reveal the contribution of WAT beiging decline to age-related metabolic disorder and suggest nutritional intervention, specifically targeting WAT beiging, as an effective approach to metabolic health during aging.

Endothelial progeria induces adipose tissue senescence and impairs insulin sensitivity through senescence associated secretory phenotype

Vascular senescence is thought to play a crucial role in an ageing-associated decline of organ functions; however, whether vascular senescence is causally implicated in age-related disease remains unclear. Here we show that endothelial cell (EC) senescence induces metabolic disorders through the senescence-associated secretory phenotype. Senescence-messaging secretomes from senescent ECs induced a senescence-like state and reduced insulin receptor substrate-1 in adipocytes, which thereby impaired insulin signaling. We generated EC-specific progeroid mice that overexpressed the dominant negative form of telomeric repeat-binding factor 2 under the control of the Tie2 promoter. EC-specific progeria impaired systemic metabolic health in mice in association with adipose tissue dysfunction even while consuming normal chow. Notably, shared circulation with EC-specific progeroid mice by parabiosis sufficiently transmitted the metabolic disorders into wild-type recipient mice. Our data provides direct evidence that EC senescence impairs systemic metabolic health, and thus establishes EC senescence as a bona fide risk for age-related metabolic disease.

Two polyphenol-rich Brazilian fruit extracts protect from diet-induced obesity and hepatic steatosis in mice.

Consumption of polyphenol-rich food is associated with better metabolic health. Tucum-do-Pantanal (Bactris setosa Mart) and taruma-do-cerrado (Vitex cymosa Bertero ex Spreng) are underexploited native Brazilian fruits with an important source of phytochemicals. In this study, we assessed the effects of 100 mg kg-1 tucum (TPE) and taruma (TCE) extracts on diet-induced obesity (DIO) C57BL/6J mice. After 8 weeks of daily treatment, TPE and TCE were found to significantly prevented the diet-induced body weight gain and fully protected against hepatic steatosis associated with a tendency to stimulate hepatic AMPK phosphorylation. TPE reduced visceral obesity and improved glucose metabolism as revealed by an improvement of the insulin tolerance test, a reduction in the insulin fasting level, and a decreased glucose-induced hyperinsulinemia during an oral glucose tolerance test. TPE and TCE showed promising effects on the treatment of obesity and NAFLD, furthermore, TPE on insulin resistance.

Metabolically and immunologically beneficial impact of extra virgin olive and flaxseed oils on composition of gut microbiota in mice

PurposeExtra virgin olive oil (EVOO) and flaxseed oil (FO) contain a variety of constituents beneficial for chronic inflammation and cardio-metabolic derangement. However, little is known about the impact of EVOO and FO on dysbiosis of gut microbiota, intestinal immunity, and barrier. We, therefore, aimed to assess the impact of EVOO and FO on gut microbiota, mucosal immunity, barrier integrity, and metabolic health in mice.MethodsC57BL/6 J mice were exposed to a low-fat (LF), lard (HF), high fat-extra virgin olive oil (HF-EVOO), or high fat-flaxseed oil (HF-FO) diet for 10 weeks. Gut microbiota assessment was undertaken using 16S rRNA sequencing. Levels of mRNA for genes involved in intestinal inflammation and barrier maintenance in the intestine and bacterial infiltration in the liver were measured by qPCR.ResultsHF-EVOO or HF-FO mice showed greater diversity in gut microbiota as well as a lower abundance of the Firmicutes phylum in comparison with HF mice (P < 0.05). The qPCR analyses revealed that mRNA level of FoxP3, a transcription factor, and IL-10, an inducer of regulatory T cells, was significantly elevated in the intestines of mice-fed HF-EVOO in comparison with mice-fed HF (P < 0.05). The mRNA level of the antimicrobial peptide, RegӀӀӀγ, was markedly elevated in the intestines of HF-EVOO and HF-FO compared with HF group (P < 0.05).ConclusionsOur data suggest that the consumption of EVOO or FO can beneficially impact gut microbiota, enhance gut immunity, and assist in the preservation of metabolic health in mice.

From the Literature

From the Literature

Loss of DBC1 (CCAR2) affects TNFα-induced lipolysis and Glut4 gene expression in murine adipocytes.

STAT5A (signal transducer and activator of transcription 5A) is a transcription factor that plays a role in adipocyte development and function. In this study, we report DBC1 (deleted in breast cancer 1; also known as CCAR2) as a novel STAT5A-interacting protein. DBC1 has been primarily studied in tumor cells, but there is evidence that loss of this protein may promote metabolic health in mice. Currently, the functions of DBC1 in mature adipocytes are largely unknown. Using immunoprecipitation and immunoblotting techniques, we confirmed that there is an association between endogenous STAT5A and DBC1 proteins under physiological conditions in the adipocyte nucleus that is not dependent upon STAT5A tyrosine phosphorylation. We used siRNA to knockdown DBC1 in 3T3-L1 adipocytes to determine the impact on STAT5A activity, adipocyte gene expression, and TNFα (tumor necrosis factor α)-regulated lipolysis. The loss of DBC1 did not affect the expression of several STAT5A target genes including Socs3, Cish, Bcl6, Socs2, and Igf1 However, we did observe decreased levels of TNFα-induced glycerol and free fatty acids released from adipocytes with reduced DBC1 expression. In addition, DBC1-knockdown adipocytes had increased Glut4 expression. In summary, DBC1 can associate with STAT5A in adipocyte nucleus, but it does not appear to impact regulation of STAT5A target genes. Loss of adipocyte DBC1 modestly increases Glut4 gene expression and reduces TNFα-induced lipolysis. These observations are consistent with in vivo observations that show loss of DBC1 promotes metabolic health in mice.

Activation of neuregulin-4 in adipocytes improves metabolic health by enhancing adipose tissue angiogenesis

Obesity often causes systemic metabolic disorders in close association with adipose tissue dysfunction. Adipose tissue contains well-developed vasculatures, and obesity mediates vascular rarefaction that causes hypoxia and triggers inflammation in adipose tissue. Adipose tissue-derived neuregulin-4 (Nrg4) is an immerging factor that is critically involved in metabolic homeostasis. We recently identified that Nrg4 is an angiogenic adipokine that plays an important role in maintaining adipose tissue vasculature. Here, we further validated its beneficial role in metabolic health primarily by enhancing adipose tissue angiogenesis. Targeted activation of Nrg4 in adipocytes improved metabolic health in mice under both normal and high fat dietary condition without changes in body weight. Activation of Nrg4 increased blood vessels in white adipose tissue, and ameliorated adipose tissue hypoxia under obese condition. Of note, inhibition of angiogenesis by sugen-treatment abolished the beneficial effects of Nrg4 on systemic metabolic health. Furthermore, targeted inhibition of Nrg4-ErbB signaling in adipose tissue vasculature using prohibitin binding peptide-conjugated nanocarrier abrogated the enhanced adipose tissue angiogenesis, and canceled the improved metabolic health induced by Nrg4 activation. These data further support a crucial role of Nrg4 in maintaining systemic metabolic homeostasis at least partially through enhancing adipose tissue angiogenesis.

The effects of sex and age on the metabolic response to methionine deprivation, a novel intervention for the treatment of obesity and diabetes

Obesity has become an increasing health problem in the United States and worldwide; effective interventions that promote weight loss are urgently needed. Dietary restriction of methionine promotes leanness and improves metabolic health in mice and humans. However, poor long‐term adherence to this diet limits its translational potential. To address this problem, we have developed short‐term methionine deprivation as a rapid and effective strategy to reduce adiposity and promote metabolic health.We examined the effects of a short‐term MD regimen on the metabolic health of C57BL/6J mice of both sexes, including 1) young mice raised on a chow diet; 2) young mice preconditioned with a Western high‐fat, high‐sucrose diet for 12 weeks; and 3) aged mice on a chow diet. We examined weight, body composition, glucose and insulin tolerance, food intake, activity and energy expenditure. We further examined hepatic steatosis and gene expression in multiple tissues. Using metabolomic and proteomic approaches, we also determined methionine metabolite levels and evaluated global histone post‐translational modification profiles in the liver. Finally, as dietary methionine is an agonist of the protein kinase mTORC1 (mechanistic Target of Rapamycin Complex 1), which is proposed to play a key role in the metabolic response to amino acid‐restricted diets, we examined the role of hepatic mTORC1 in the metabolic response to MD using a mouse model of constitutive hepatic mTORC1 activity.We find that a short‐term MD regimen preferentially reduces fat mass, restoring normal body weight and glycemic control to diet‐induced obese mice of both sexes. Additionally, we have examined the persistence of these metabolic changes in young and aged mice. We find that the benefits of MD do not accrue from calorie restriction, but instead result from increased energy expenditure. Intriguingly, MD promotes increased energy expenditure in both sexes, but induces the FGF21‐UCP1 axis only in males. We also observed sex‐specific effects of MD on lipid metabolism. The metabolic analysis revealed that MD significantly decreases levels of methionine as well as the methionine metabolite SAM (S‐adenosyl methionine) in the liver, and that accordingly, histone methylation in the liver is dramatically downregulated compared to control. Furthermore, using liver‐specific TSC1 knockout mice, which have constitutively active hepatic mTORC1, we determined that the metabolic effects of MD do not depend upon reduced hepatic mTORC1 signaling.Our study sheds new light on the mechanisms by which dietary methionine regulates metabolic health. In particular, our results suggest that sex‐dependent mechanisms may mediate the metabolic response to decreased dietary methionine, and that the FGF21‐UCP1 axis may be dispensable for the metabolic benefits of MD in females. Our results also demonstrate that the metabolic benefits of MD are not mediated by suppression of hepatic mTORC1 signaling. Our study clearly demonstrates the translational potential of MD or MD‐mimetics for the treatment of obesity and type 2 diabetes, diseases which are highly prevalent in the aged.Support or Funding InformationThis research was supported in part by grants from the NIH AG041765 (D.W.L.), AG050135 (D.W.L.), AG051974 (D.W.L.), GM059789‐15/P250VA (J.M.D), a New Investigator Program Award (D.W.L.) and a Collaborative Health Sciences Program Award (V.L.C.) from the Wisconsin Partnership Program, the V. Foundation for Cancer Research (V.L.C.), and a Glenn Foundation Award for Research in the Biological Mechanisms of Aging (D.W.L.), as well as startup funds from the UW‐Madison School of Medicine and Public Health and the UW‐Madison Department of Medicine (V.L.C. and D.W.L.). This research was conducted while D.W.L. was an AFAR Research Grant recipient from the American Federation for Aging Research. D.Y. is supported in part by a fellowship from the American Heart Association (17PRE33410983). S.A.H. is supported by a training grant from the NIH/NIDDK (T32DK007665). This work was supported using facilities and resources from the William S. Middleton Memorial Veterans Hospital. This work does not represent the views of the Department of Veterans Affairs or the United States Government.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.