The journal retracts the article "Cold Press Nigella Sativa oil standardized to 3%, thymoquinone Potentiates Omega-3 Protection against Obesity-Induced Oxidative Stress, Inflammation and Insulin Resistance via Conversion of White to Beige Fat in Mice" [...].
Background: Pathogenic factors driving obesityinduced fatty liver disease (NAFLD) and insulin resistance are not fully understood. While the mechanisms are unclear, we recognize that high fat diets contribute to obesity, insulin resistance, deleterious ROS production, and fibrogenesis. There is evidence that high fat diets can cause an increased risk of diabetes and consequent cardiovascular disease. The chronic overnutrition from high fat diets is increasingly seen as a risk factor for cardio-metabolic diseases. Previously, we established that pharmacological and herbal medication increase the antioxidant and antiobesity gene heme oxygenase -1 (HO-1), which reduces inflammatory adipokines and hepatosteatosis. Objective: We examined whether targeting adipocytes to overexpress HO-1 would ameliorate the negative metabolic effects of a prolonged high fat diet (HFD) in mice in hepatocyes as well as adipocytes, to reverse NAFLD and prevent subsequent cardiovascular complications. Methods: Mice were administered lentiviral adiponectin-HO-1 after 20 weeks of a HFD and continued on this diet for 8 more weeks, for a total of 28 weeks of HFD. Mice were treated with HO-1 or a sham virus. Mice were euthanized at 28 weeks. Results: HFD induced adipocyte hypertrophy, increased levels of inflammatory adipokines, and the presence of hepatic lipid droplets and steatosis. The treated mice had less liver lipid droplet accumulation, with normal glucose tolerance and vascular function. These beneficial effects of adipocytetargeted expression of HO-1 correlated with a reduction in inflammatory adipokines and increased insulin receptor phosphorylation. We have demonstrated that selective increased HO-1 expression in adipose tissue via viral transfection, improved mitochondrial function in both adipose tissue and hepatic tissue in a murine model of high fat diet-induced obesity and NAFLD. Conclusion: This Journal of Food & Nutritional Sciences [2022; 4(1): 1-20] Open Access This work is licensed under a Creative Commons Attribution 4.0 International License. represents a unique therapeutic strategy for treating obesity-associated hepatic steatosis and metabolic syndrome from chronic overnutrition and downstream cardiovascular complications.
Background: Obesity affects ∼20% of children in the United States and reports of successful dietary treatment are lacking. This study aimed to determine the change in body weight in severely obese youth after carbohydrate-restricted dietary intervention. Methods: This single-center study of a carbohydrate-restricted diet (≤30 grams per day), with unlimited calories, fat, and protein for 3-4 months, examined two groups of severely obese youth of ages 5-18 years: Group A, retrospectively reviewed charts of severely obese youth referred to the Pediatric Obesity Clinic at Hoops Family Children's Hospital and the Ambulatory Division of Marshall Pediatrics, Marshall University School of Medicine, in Huntington, WV, between July 1, 2014 and June 30, 2017 (n = 130), and Group B, prospective participants, referred between July 1, 2018 and December 31, 2018, followed with laboratory studies pre- and postdietary intervention (n = 8). Results: In Group A, 310 participants began the diet, 130 (42%) returned after 3-4 months. Group B had 14 enrollees who began the diet, and 8 followed up at 3-4 months (57%). Girls compared with boys were more likely to complete the diet (P = 0.02). Participants <12 years age were almost twice as likely to complete the diet compared with those 12-18 years (64% vs. 36%, P < 0.01); however, the older group subjects who completed the diet had the same percentage of weight loss compared with those <12 years (6.9% vs. 6.9%). Group A had reductions in weight of 5.1 kg (P < 0.001), body mass index (BMI) 2.5 kg/m2 (P < 0.001), and percentage weight loss 6.9% (P < 0.001). Group B had reductions in weight 9.6 kg (P < 0.01), BMI 4 kg/m2 (P < 0.01), and percentage weight loss 9% (P < 0.01). In addition, participants had significant reductions of fasting serum insulin (P < 0.01), triglycerides (P < 0.01), and 20-hydroxyeicosatetraenoic acid (P < 0.01). Conclusions: This study demonstrated a carbohydrate-restricted diet, utilized short term, effectively reduced weight in a large percentage of severely obese youth, and can be replicated in a busy primary care office.
Milk thistle cold press oil (MTO) is an herbal remedy derived fromSilybum marianumwhich contains a low level of silymarin and mixture of polyphenols and flavonoids. The effect of MTO on the cardiovascular and metabolic complications of obesity was studied in mice that were fed a high-fat diet (HFD) for 20 weeks and treated with MTO for the final 8 weeks of the diet. MTO treatment attenuated HFD-induced obesity, fasting hyperglycemia, hypertension, and induced markers of mitochondrial fusion and browning of white adipose. Markers of inflammation were also attenuated in both adipose and the liver of MTO-treated mice. In addition, MTO resulted in the improvement of liver fibrosis. These results demonstrate that MTO has beneficial actions to attenuate dietary obesity-induced weight gain, hyperglycemia, hypertension, inflammation, and suggest that MTO supplementation may prove beneficial to patients exhibiting symptoms of metabolic syndrome. Practical applications Natural supplements are increasingly being considered as potential therapies for many chronic cardiovascular and metabolic diseases. Milk thistle cold press oil (MTO) is derived fromSilybum marianumwhich is used as a dietary supplement in different parts of the world. The results of the present study demonstrate that MTO supplementation normalizes several metabolic and cardiovascular complications arising from dietary-induced obesity. MTO supplementation also had anti-inflammatory actions in the adipose as well as the liver. These results suggest that supplementation of MTO into the diet of obese individuals may afford protection against the worsening of cardiovascular and metabolic disease and improve inflammation and liver fibrosis.
: Obesity is a risk factor for vascular dysfunction and insulin resistance. The study aim was to demonstrate that adipocyte-specific HO-1 (heme oxygenase-1) gene therapy is a therapeutic approach for preventing the development of obesity-induced metabolic disease in an obese-mice model. Specific expression of HO-1 in adipose tissue was achieved by using a lentiviral vector expressing HO-1 under the control of the adiponectin vector (Lnv-adipo-HO-1). Mice fed a high-fat diet (HFD) developed adipocyte hypertrophy, fibrosis, decreased mitochondrial respiration, increased levels of inflammatory adipokines, insulin resistance, vascular dysfunction, and impaired heart mitochondrial signaling. These detrimental effects were prevented by the selective expression of HO-1 in adipocytes. Lnv-adipo-HO-1-transfected mice on a HFD display increased cellular respiration, increased oxygen consumption, increased mitochondrial function, and decreased adipocyte size. Moreover, RNA arrays confirmed that targeting adipocytes with HO-1 overrides the genetic susceptibility of adiposopathy and correlated with restoration of the expression of anti-inflammatory, thermogenic, and mitochondrial genes. Our data demonstrate that HO-1 gene therapy improved adipose tissue function and had positive impact on distal organs, suggesting that specific targeting of HO-1 gene therapy is an attractive therapeutic approach for improving insulin sensitivity, metabolic activity, and vascular function in obesity.
Significance: Heme oxygenase (HO) plays a pivotal role in both vascular and metabolic functions and is involved in many physiological and pathophysiological processes in vascular endothelial cells (ECs) and adipocytes. Recent Advances: From the regulation of adipogenesis in adipose tissue to the adaptive response of vascular tissue in the ECs, HO plays a critical role in the capability of the vascular system to respond and adjust to insults in homeostasis. Recent studies show that HO-1 through regulation of adipocyte and adipose tissue functions ultimately aid not only in local but also in systemic maintenance of homeostasis. Critical Issues: Recent advances have revealed the existence of a cross talk between vascular ECs and adipocytes in adipose tissue. In the pathological state of obesity, this cross talk contributes to the condition's adverse chronic effects, and we propose that specific targeting of the HO-1 gene can restore signaling pathways and improve both vascular and adipose functions. Future Directions: A complete understanding of the role of HO-1 in regulation of cardiovascular homeostasis is important to comprehend the homeostatic regulation as well as in cardiovascular disease. Efforts are required to highlight the effects and the ability to target the HO-1 gene in models of obesity with an emphasis on the role of pericardial fat on cardiovascular health.
Excessive lipid accumulation in white adipose tissue (WAT) results in adipocyte hypertrophy and chronic low-grade inflammation, which is the major cause of obesity-associated insulin resistance and consequent metabolic disease. The development of beige adipocytes in WAT (browning of WAT) increases energy expenditure and has been considered as a novel strategy to counteract obesity. Thymoquinone (TQ) is the main bioactive quinone derived from the plant Nigella Sativa and has antioxidative and anti-inflammatory capacities. Fish oil omega 3 (ω3) enhances both insulin sensitivity and glucose homeostasis in obesity, but the involved mechanisms remain unclear. The aim of this study is to explore the effects of TQ and ω3 PUFAs (polyunsaturated fatty acids) on obesity-associated inflammation, markers of insulin resistance, and the metabolic effects of adipose tissue browning. 3T3-L1 cells were cultured to investigate the effects of TQ and ω3 on the browning of WAT. C57BL/6J mice were fed a high-fat diet (HFD), supplemented with 0.75% TQ, and 2% ω3 in combination for eight weeks. In 3T3-L1 cells, TQ and ω3 reduced lipid droplet size and increased hallmarks of beige adipocytes such as uncoupling protein-1 (UCP1), PR domain containing 16 (PRDM16), fibroblast growth factor 21 (FGF21), Sirtuin 1 (Sirt1), Mitofusion 2 (Mfn2), and heme oxygenase 1 (HO-1) protein expression, as well as increased the phosphorylation of Protein Kinase B (AKT) and insulin receptors. In the adipose tissue of HFD mice, TQ and ω3 treatment attenuated levels of inflammatory adipokines, Nephroblastoma Overexpressed (NOV/CCN3) and Twist related protein 2 (TWIST2), and diminished adipocyte hypoxia by decreasing HIF1α expression and hallmarks of beige adipocytes such as UCP1, PRDM16, FGF21, and mitochondrial biogenesis markers Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α), Sirt1, and Mfn2. Increased 5′ adenosine monophosphate-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) phosphorylation and HO-1 expression were observed in adipose with TQ and ω3 treatment, which led to increased pAKT and pIRS1 Ser307 expression. In addition to the adipose, TQ and ω3 also increased inflammation and markers of insulin sensitivity in the liver, as demonstrated by increased phosphorylated insulin receptor (pIR tyr972), insulin receptor beta (IRβ), UCP1, and pIRS1 Ser307 and reduced NOV/CCN3 expression. Our data demonstrate the enhanced browning of WAT from TQ treatment in combination with ω3, which may play an important role in decreasing obesity-associated insulin resistance and in reducing the chronic inflammatory state of obesity.
Non-alcoholic fatty liver disease (NAFLD) is associated with obesity and is considered to be an inflammatory disorder characterized by fatty acid accumulation, oxidative stress, and lipotoxicity. We have previously reported that epoxyeicosatrienoic acid-agonist (EET-A) has multiple beneficial effects on cardiac, renal and adipose tissue function while exhibiting both anti-inflammatory and anti-oxidant activities. We hypothesized that EET-A intervention would play a central role in attenuation of obesity-induced steatosis and hepatic fibrosis that leads to NAFLD.We studied the effect of EET-A on fatty liver using db/db mice as a model of obesity. Mice were fed a high fat diet (HFD) for 16 weeks and administered EET-A twice weekly for the final 8 weeks.db/db mice fed HFD significantly increased hepatic lipid accumulation as manifested by increases in NAS scores, hepatic fibrosis, insulin resistance, and inflammation, and decreases in mitochondrial mitofusin proteins (Mfn 1/2) and anti-obesity genes Fibroblast growth factor 21 (FGF21) and Cellular Repressor of E1A-Stimulated Genes 1 (CREG1). EET-A administration reversed the decrease in these genes and reduced liver fibrosis. Knockout of Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) in EET-A treated mice resulted in a reversal of the beneficial effects of EET-A administration.EET-A intervention diminishes fatty acid accumulation, fibrosis, and NFALD associated with an increase in HO-1-PGC1α and increased insulin receptor phosphorylation. A pharmacological strategy involving EETs may offer a potential therapeutic approach in preventing fibrosis, mitochondrial dysfunction, and the development of NAFLD.
Background: Non-alcoholic fatty liver disease (NAFLD) is associated with obesity and is considered to be an inflammatory disorder characterized by fatty acid accumulation, oxidative stress, and lipotoxicity. We have previously reported that epoxyeicosatrienoic acid-agonist (EET-A) has multiple beneficial effects on cardiac, renal and adipose tissue function while exhibiting both anti-inflammatory and anti-oxidant activities. We hypothesized that EET-A intervention would play a central role in attenuation of obesity-induced steatosis and hepatic fibrosis that leads to NAFLD. Methods: We studied the effect of EET-A on fatty liver using db/db mice as a model of obesity. Mice were fed a high fat diet (HFD) for 16 weeks and administered EET-A twice weekly for the final 8 weeks. Results: db/db mice fed HFD significantly increased hepatic lipid accumulation as manifested by increases in NAS scores, hepatic fibrosis, insulin resistance, and inflammation, and decreases in mitochondrial mitofusin proteins (Mfn 1/2) and anti-obesity genes Fibroblast growth factor 21 (FGF21) and Cellular Repressor of E1A-Stimulated Genes 1 (CREG1). EET-A administration reversed the decrease in these genes and reduced liver fibrosis. Knockout of Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1 alpha) in EET-A treated mice resulted in a reversal of the beneficial effects of EET-A administration. Conclusions: EET-A intervention diminishes fatty acid accumulation, fibrosis, and NFALD associated with an increase in HO-1-PGC1 alpha and increased insulin receptor phosphorylation. A pharmacological strategy involving EETs may offer a potential therapeutic approach in preventing fibrosis, mitochondrial dysfunction, and the development of NAFLD.
BACKGROUND:Non-alcoholic fatty liver disease (NAFLD) is associated with obesity and is considered to be an inflammatory disorder characterized by fatty acid accumulation, oxidative stress, and lipotoxicity. We have previously reported that epoxyeicosatrienoic acid-agonist (EET-A) has multiple beneficial effects on cardiac, renal and adipose tissue function while exhibiting both anti-inflammatory and anti-oxidant activities. We hypothesized that EET-A intervention would play a central role in attenuation of obesity-induced steatosis and hepatic fibrosis that leads to NAFLD. METHODS:We studied the effect of EET-A on fatty liver using db/db mice as a model of obesity. Mice were fed a high fat diet (HFD) for 16 weeks and administered EET-A twice weekly for the final 8 weeks. RESULTS:db/db mice fed HFD significantly increased hepatic lipid accumulation as manifested by increases in NAS scores, hepatic fibrosis, insulin resistance, and inflammation, and decreases in mitochondrial mitofusin proteins (Mfn 1/2) and anti-obesity genes Fibroblast growth factor 21 (FGF21) and Cellular Repressor of E1A-Stimulated Genes 1 (CREG1). EET-A administration reversed the decrease in these genes and reduced liver fibrosis. Knockout of Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) in EET-A treated mice resulted in a reversal of the beneficial effects of EET-A administration. CONCLUSIONS:EET-A intervention diminishes fatty acid accumulation, fibrosis, and NFALD associated with an increase in HO-1-PGC1α and increased insulin receptor phosphorylation. A pharmacological strategy involving EETs may offer a potential therapeutic approach in preventing fibrosis, mitochondrial dysfunction, and the development of NAFLD.
Aim: Nigella sativa seeds contain a high amount of Thymoquinone (TQ), an antioxidant. We therefore hypothesized that Nigella sativa oil would, through the antioxidant properties of TQ ameliorate obesity-induced hyperglycemia and decrease blood pressure and OX-LDL in obese mice. Methods: Commencing at eight weeks of age, C57B16 male mice were fed a high fat diet (HF) for 20 weeks. Mice were divided into three groups of five animals each as follows: group 1) Lean, group 2) HF diet, group 3) HF diet treated for the last 8 weeks with 3%TQ. Inflammatory biomarkers, antioxidant biomarkers, mitochondrial biogenesis and tissue fat accumulation and hepatic steatosis were determined. Results: 3% TQ treatment resulted in an increase of oxygen consumption decreased fasting glucose and blood pressure (P<0.05) as compared in obese mice. TQ treatment increased both the quantity of hepatic HO-1, and HO activity in response to 3% TQ. Additionally, mitochondrial Mfn2, PGC1α, insulin receptor phosphorylation in response to TQ while decreased LDL and OX-LDL (P<0.05) and haptic lipid accumulation. Conclusion: Fundamentally, TQ intervention attenuated the obesity-mediated decrease of oxygen consumption, fasting glucose, improved mitochondrial biogenesis through an increase and in levels of HO-1 that is associated with ablated HF-induced LDL. Our findings indicate a potential clinical role for TQ in the prevention of obesity-related steatosis in metabolic disease.
We have shown that epoxyeicosatrienoic acids (EETs), specifically 11,12- and 14,15-EETs, reduce adipogenesis in human mesenchymal stem cells and mouse preadipocytes (3T-3L1). In this study, we explore the effects of soluble epoxide hydrolase (sEH) deletion on various aspects of adipocyte-function, including programing for white vs. beige-like fat, and mitochondrial and thermogenic gene-expressions. We further hypothesize that EETs and heme-oxygenase 1 (HO-1) form a synergistic, functional module whose effects on adipocyte and vascular function is greater than the effects of sEH deletion alone. In in vitro studies, we examined the effect of sEH inhibitors on MSC-derived adipocytes. MSC-derived adipocytes exposed to AUDA, an inhibitor of sEH, exhibit an increased number of small and healthy adipocytes, an effect reproduced by silINA for sEH. in vivo studies indicate that sEH deletion results in a significant decrease in adipocyte size, inflammatory adipokines NOV, TNF alpha, while increasing adiponectin (p < 0.05). These findings are associated with a decrease in body weight (p < 0.05), and visceral fat (p < 0.05). Importantly, sEH deletion was associated with a significant increase in Mfnl, COX 1, UCP1 and adiponectin (p < 0.03). sEH deletion was manifested by a significant increase in EETs isomers 5,6-EET, 8,9-EET, 11,12-EET, and 14,15-EET and an increased EETs/DHETEs ratio. Notably, activation of HO-1 gene expression further increased the levels of EETs, suggesting that the antioxidant HO-1 system protects EETs from degradation by ROS. These results are novel in that sEH deletion, while increasing EET levels, resulted in reprograming of white fat to express mitochondrial and thermogenic genes, a phenotype characteristic of beige-fat. Thus, EETs agonist(s) and sEH inhibitors may have therapeutic potential in the treatment of metabolic syndrome and obesity.
20-Hydroxyeicosatetraenoic acid (20-HETE) has been shown to positively correlate with body mass index, hyperglycemia, and plasma insulin levels. This study seeks to identify a causal relationship between 20-HETE and obesity-driven insulin resistance. Cyp4a14 −/− male mice, a model of 20-HETE overproduction, were fed a regular or high-fat diet (HFD) for 15 wk. 20-SOLA [2,5,8,11,14,17-hexaoxanonadecan-19-yl 20-hydroxyeicosa-6( Z),15( Z)-dienoate], a 20-HETE antagonist, was administered from week 0 or week 7 of HFD. HFD-fed mice gained significant weight (16.7 ± 3.2 vs. 3.8 ± 0.35 g, P < 0.05) and developed hyperglycemia (157 ± 3 vs. 121 ± 7 mg/dl, P < 0.05) and hyperinsulinemia (2.3 ± 0.4 vs. 0.5 ± 0.1 ng/ml, P < 0.05) compared with regular diet-fed mice. 20-SOLA attenuated HFD-induced weight gain (9.4 ± 1 vs. 16.7 ± 3 g, P < 0.05) and normalized the hyperglycemia (157 ± 7 vs. 102 ± 5 mg/dl, P < 0.05) and hyperinsulinemia (1.1 ± 0.1 vs. 2.3 ± 0.4 ng/ml, P < 0.05). The impaired glucose homeostasis and insulin resistance in HFD-fed mice evidenced by reduced insulin and glucose tolerance were also ameliorated by 20-SOLA. Circulatory and adipose tissue 20-HETE levels significantly increased in HFD-fed mice correlating with impaired insulin signaling, including reduction in insulin receptor tyrosine (Y972) phosphorylation and increased serine (S307) phosphorylation of the insulin receptor substrate-1 (IRS-1). 20-SOLA treatments prevented changes in insulin signaling. These findings indicate that 20-HETE contributes to HFD-induced obesity, insulin resistance, and impaired insulin signaling.
We have previously shown that an Epoxyeicosatrienoic Acid (EET) -agonist has pleiotropic effects and reverses cardiomyopathy by decreasing inflammatory molecules and increasing antioxidant signaling. We hypothesized that administration of an EET agonist would increase Peroxisome proliferator-activated receptor-gamma coactivator (PGC-1α), which controls mitochondrial function and induction of HO-1 and negatively regulates the expression of the proinflammatory adipokines CCN3/NOV in cardiac and pericardial tissues. This pathway would be expected to further improve left ventricular (LV) systolic function as well as increase insulin receptor phosphorylation. Measurement of the effect of an EET agonist on oxygen consumption, fractional shortening, blood glucose levels, thermogenic and mitochondrial signaling proteins was performed. Control obese mice developed signs of metabolic syndrome including insulin resistance, hypertension, inflammation, LV dysfunction, and increased NOV expression in pericardial adipose tissue. EET agonist intervention decreased pericardial adipose tissue expression of NOV, while normalized FS, increased PGC-1α, HO-1 levels, insulin receptor phosphorylation and improved mitochondrial function, theses beneficial effect were reversed by deletion of PGC-1α. These studies demonstrate that an EET agonist increases insulin receptor phosphorylation, mitochondrial and thermogenic gene expression, decreased cardiac and pericardial tissue NOV levels, and ameliorates cardiomyopathy in an obese mouse model of the metabolic syndrome.
Previously we demonstrated that an EET‐agonist has pleiotropic effects including inhibition of Soluble Epoxide Hydrolase expression and reversed cardiomyopathy by decreasing inflammatory molecules and increasing antioxidant signaling. We hypothesized that an EET agonist would increase PGC‐1α, which controls mitochondrial function and HO‐1 induction and negatively regulates the expression of the proinflammatory adipokine NOV in both cardiac and pericardial tissues. This pathway would be expected to further improve left ventricular systolic function as well as increase insulin receptor phosphorylation. The effect of an EET agonist was measured in cardiac and pericardial adipose tissues in db/db mice on oxygen consumption, fractional shortening, blood glucose levels, thermogenic and mitochondrial signaling proteins. Control db/db mice developed signs of metabolic syndrome including insulin resistance, hypertension, inflammation, LV dysfunction, and increased NOV expression in pericardial adipose tissue. EET agonist decreased pericardial adipose tissue expression of NOV, normalized FS, increased PGC‐1α, HO‐1 levels, insulin receptor phosphorylation and improved mitochondrial function. HO‐1‐ derived carbon monoxide (CO) levels, mitochondrial function (p<0.01), insulin receptor phosphorylation (p<0.05), ATP levels and VO2 (p<0.05). Deletion of PGC‐1α reversed all of the above beneficial effects, increasing the expression of NOV and inflammatory cytokines in pericardial adipose tissue. These studies demonstrate that an EET agonist increases insulin receptor phosphorylation, mitochondrial and thermogenic gene expression, decreases cardiac and pericardial tissue NOV levels, and ameliorates cardiomyopathy in an obese mouse model of the metabolic syndrome. Further, this study demonstrated that EET‐mediated inhibition of NOV is a potential therapeutic target for the prevention of heart failure and the development of metabolic syndrome.Support or Funding InformationNational Institutes of Health grant (HL34300 to NGA)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
BackgroundObesity is a global epidemic and a major risk factor in the development of metabolic syndrome, diabetes and associated complications such as cardiovascular disease, kidney disease, hypertension, and neuropathies. Epoxyeicosatrienoic acids (EETs) are metabolites of arachidonic acid generated by a super family of cytochrome P450 (CYP) monooxygenases and epoxygenases. Hypertension caused by chronic obesity in leptin receptor deficient mice, may be linked to mitochondrial dysfunction. Previously we and others have reported the beneficial effects of epoxyeicosatrienoic acid in renal and adipose tissue function, as well as its vasodilatory action, it increases insulin sensitivity and inhibits inflammation and reactive oxygen species (ROS). We hypothesized that EET attenuates obesity‐induced renal dysfunction by improving sodium excretion, reducing the sodium‐chloride cotransporter NCC, lowering blood pressure and increasing mitochondrial and thermogenic gene levels in PGC1α dependent mice.MethodsSixteen week‐old db/db mice were divided into 3 treatment groups for an additional 16‐wk experiment; Control, EET‐A 1.5 mg/100g BW i.p. 3x/week, and EET‐A‐Ln‐PGC‐1α shRNA (Ln‐PGC‐1 α shRNA suppressed PGC‐1α protein levels in renal tissue by >50%). After 16‐wks pf treatment oxygen consumption (VO2), visceral fat and fasting blood glucose levels were determined; urine was collected and renal tissues were harvested to measure: type 2 Na‐K‐Cl cotransporters (NKCC2), epithelial Na channels‐alpha subunit (ENac), NaCl cotransporters (NCC), PGC‐1α, HO‐1, and mitochondrial biogenesis markersResultsEET‐agonist normalized glucose metabolism, renal ENaC and NCC protein expression, urinary sodium excretion and blood pressure in obese mice. EET‐agonist improved mitochondrial integrity, thermogenic genes, and PGC1α‐HO‐1‐adiponectin signaling. Knockout of PGC1α in EET‐treated mice resulted in a reversal of these beneficial effects including a decrease in sodium excretion, elevation of blood pressure and an increase in NOV. Effects of EET on perirenal adipose tissue included EET increased adiponectin, mitochondrial integrity and thermogenic genes and decreased NOV, i.e. ‘Browning’ perirenal adipose phenotype that occurs under high fat diets.ConclusionTreatment with an EET‐agonist led to the recruitment of PGC‐1α‐HO‐1, enhanced mitochondrial function, decreased perirenal fat‐derived NOV, and the downregulation of NCC channels resulting in a decrease in sodium retention in chronically obese mice. EET has the potential to serve as a powerful therapeutic agent in the treatment of obesity‐induced hypertension.Support or Funding InformationNational Institutes of Health grant (HL34300 to NGA)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Background.: We have previously reported that epoxyeicosatrienoic acid (EET) has multiple beneficial effects on renal and adipose tissue function, in addition to its vasodilatory action; it increases insulin sensitivity and inhibits inflammation. In an examination of the signaling mechanisms by which EET reduces renal and peri-renal fat function, we hypothesized that EET ameliorates obesity-induced renal dysfunction by improving sodium excretion, reducing the sodium-chloride cotransporter NCC, lowering blood pressure, and enhancing mitochondrial and thermogenic gene levels in PGC-1 alpha dependent mice. Methods: EET-agonist treatment normalized glucose metabolism, renal ENaC and NCC protein expression, urinary sodium excretion and blood pressure in obese (db/db) mice. A marked improvement in mitochondrial integrity, thermogenic genes, and PGC-1 alpha HO-1-adiponectin signaling occurred. Knockout of PGC-1 alpha in EET-treated mice resulted in a reversal of these beneficial effects including a decrease in sodium excretion, elevation of blood pressure and an increase in the pro-inflammatory adipokine nephroblastoma overexpressed gene (NOV). In the elucidation of the effects of EET on peri-renal adipose tissue, EET increased adiponectin, mitochondrial integrity, thermogenic genes and decreased NOV, i.e. "Browning' peri-renal adipose phenotype that occurs under high fat diets. Taken together, these data demonstrate a critical role of an EET agonist in the restoration of healthy adipose tissue with reduced release of inflammatory molecules, such as AngII and NOV, thereby preventing their detrimental impact on sodium absorption and NCC levels and the development of obesity-induced renal dysfunction.
Aim. Nonalcoholic steatohepatitis (NASH) is the consequence of insulin resistance, fatty acid accumulation, oxidative stress, and lipotoxicity. We hypothesize that an increase in the inflammatory adipokine NOV decreases antioxidant Heme Oxygenase 1 (HO-1) levels in adipose and hepatic tissue, resulting in the development of NASH in obese mice. Methods. Mice were fed a high fat diet (HFD) and obese animals were administered an HO-1 inducer with or without an inhibitor of HO activity to examine levels of adipose-derived NOV and possible links between increased synthesis of inflammatory adipokines and hepatic pathology. Results. NASH mice displayed decreased HO-1 levels and HO activity, increased levels of hepatic heme, NOV, MMP2, hepcidin, and increased NAS scores and hepatic fibrosis. Increased HO-1 levels are associated with a decrease in NOV, improved hepatic NAS score, ameliorated fibrosis, and increases in mitochondrial integrity and insulin receptor phosphorylation. Adipose tissue function is disrupted in obesity as evidenced by an increase in proinflammatory molecules such as NOV and a decrease in adiponectin. Importantly, increased HO-1 levels are associated with a decrease of NOV, increased adiponectin levels, and increased levels of thermogenic and mitochondrial signaling associated genes in adipose tissue. Conclusions. These results suggest that the metabolic abnormalities in NASH are driven by decreased levels of hepatic HO-1 that is associated with an increase in the adipose-derived proinflammatory adipokine NOV in our obese mouse model of NASH. Concurrently, induction of HO-1 provides protection against insulin resistance as seen by increased insulin receptor phosphorylation. Pharmacological increases in HO-1 associated with decreases in NOV may offer a potential therapeutic approach in preventing fibrosis, mitochondrial dysfunction, and the development of NASH.
Background: Obstructive sleep apnea (OSA) is strongly associated with cardiovascular and metabolic abnormalities, although the mechanism driving this association is not well understood. NOV/CCN3, a multifunctional extracellular matrix protein, may play a mechanistic and/or prognostic role in these associations. We hypothesized that patients with OSA will have increased levels of NOV, and that NOV can serve as a biomarker in patients to predict OSA as well as metabolic and cardiac risk. Materials and Methods: 10 morbidly obese subjects presenting to the sleep laboratory for clinical evaluation of possible OSA and 10 healthy lean controls underwent overnight polysomnography and clinical evaluation. Blood samples were analyzed for NOV levels, adiponectin, and IL-6. Results: OSA was found in 9 obese subjects and 3 lean subjects. NOV levels were significantly higher in the obese vs lean group (2.2±0.3 vs 1.4±0.2 fold change, p<0.03) while apnea-hypopnea index (AHI) was similarly higher in the obese vs lean group (22.9±6.7 vs 8.4±4.1 events/hr, p<0.03). NOV and AHI were positively correlated (ρ=0.49, p=0.033). IL-6 was elevated while adiponectin was reduced in obese vs lean. Conclusions: NOV levels and AHI, a measure of OSA severity, were higher in obese subjects vs lean controls and were correlated with each other. NOV may be a marker of OSA severity and a biomarker for cardiovascular and metabolic disease in OSA patients.