scholarly journals Catalase-dependent H2O2consumption by cardiac mitochondria and redox-mediated loss in insulin signaling

2016 ◽  
Vol 311 (5) ◽  
pp. H1091-H1096 ◽  
Author(s):  
Paul M. Rindler ◽  
Angela Cacciola ◽  
Michael Kinter ◽  
Luke I. Szweda
Keyword(s):  
Oxidative Stress ◽  
Glutathione Peroxidase ◽  
Binding Affinity ◽  
Insulin Signaling ◽  
Dietary Fat ◽  
High Fat Diet ◽  
Cardiac Mitochondria ◽  
High Fat ◽  
Akt Phosphorylation ◽  
Selective Increase

We have recently demonstrated that catalase content in mouse cardiac mitochondria is selectively elevated in response to high dietary fat, a nutritional state associated with oxidative stress and loss in insulin signaling. Catalase and various isoforms of glutathione peroxidase and peroxiredoxin each catalyze the consumption of H2O2. Catalase, located primarily within peroxisomes and to a lesser extent mitochondria, has a low binding affinity for H2O2relative to glutathione peroxidase and peroxiredoxin. As such, the contribution of catalase to mitochondrial H2O2consumption is not well understood. In the current study, using highly purified cardiac mitochondria challenged with micromolar concentrations of H2O2, we found that catalase contributes significantly to mitochondrial H2O2consumption. In addition, catalase is solely responsible for removal of H2O2in nonrespiring or structurally disrupted mitochondria. Finally, in mice fed a high-fat diet, mitochondrial-derived H2O2is responsible for diminished insulin signaling in the heart as evidenced by reduced insulin-stimulated Akt phosphorylation. While elevated mitochondrial catalase content (∼50%) enhanced the capacity of mitochondria to consume H2O2in response to high dietary fat, the selective increase in catalase did not prevent H2O2-induced loss in cardiac insulin signaling. Taken together, our results indicate that mitochondrial catalase likely functions to preclude the formation of high levels of H2O2without perturbing redox-dependent signaling.

scholarly journals Programming With Varying Dietary Fat Content Alters Cardiac Insulin Receptor, Glut4 and FoxO1 Immunoreactivity in Neonatal Rats, Whereas High Fat Programming Alters Cebpa Gene Expression in Neonatal Female Rats

2022 ◽  
Vol 12 ◽  
Author(s):  
Annelene Govindsamy ◽  
Samira Ghoor ◽  
Marlon E. Cerf
Keyword(s):  
Gene Expression ◽  
Insulin Receptor ◽  
Insulin Signaling ◽  
Dietary Fat ◽  
High Fat Diet ◽  
Female Offspring ◽  
Fat Content ◽  
Neonatal Rats ◽  
Cardiac Physiology ◽  
High Fat

Fetal programming refers to an intrauterine stimulus or insult that shapes growth, development and health outcomes. Dependent on the quality and quantity, dietary fats can be beneficial or detrimental for the growth of the fetus and can alter insulin signaling by regulating the expression of key factors. The effects of varying dietary fat content on the expression profiles of factors in the neonatal female and male rat heart were investigated and analyzed in control (10% fat), 20F (20% fat), 30F (30% fat) and 40F (40% fat which was a high fat diet used to induce high fat programming) neonatal rats. The whole neonatal heart was immunostained for insulin receptor, glucose transporter 4 (Glut4) and forkhead box protein 1 (FoxO1), followed by image analysis. The expression of 84 genes, commonly associated with the insulin signaling pathway, were then examined in 40F female and 40F male offspring. Maintenance on diets, varying in fat content during fetal life, altered the expression of cardiac factors, with changes induced from 20% fat in female neonates, but from 30% fat in male neonates. Further, CCAAT/enhancer-binding protein alpha (Cebpa) was upregulated in 40F female neonates. There was, however, differential expression of several insulin signaling genes in 40F (high fat programmed) offspring, with some tending to significance but most differences were in fold changes (≥1.5 fold). The increased immunoreactivity for insulin receptor, Glut4 and FoxO1 in 20F female and 30F male neonatal rats may reflect a compensatory response to programming to maintain cardiac physiology. Cebpa was upregulated in female offspring maintained on a high fat diet, with fold increases in other insulin signaling genes viz. Aebp1, Cfd (adipsin), Adra1d, Prkcg, Igfbp, Retn (resistin) and Ucp1. In female offspring maintained on a high fat diet, increased Cebpa gene expression (concomitant with fold increases in other insulin signaling genes) may reflect cardiac stress and an adaptative response to cardiac inflammation, stress and/or injury, after high fat programming. Diet and the sex are determinants of cardiac physiology and pathophysiology, reflecting divergent mechanisms that are sex-specific.

scholarly journals Antioxidants preserve redox balance and inhibit c-Jun-N-terminal kinase pathway while improving insulin signaling in fat-fed rats: evidence for the role of oxidative stress on IRS-1 serine phosphorylation and insulin resistance

2008 ◽  
Vol 197 (2) ◽  
pp. 287-296 ◽  
Author(s):  
R Vinayagamoorthi ◽  
Zachariah Bobby ◽  
M G Sridhar
Keyword(s):  
Oxidative Stress ◽  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Insulin Signaling ◽  
High Fat Diet ◽  
Redox Balance ◽  
Serine Phosphorylation ◽  
Control Group ◽  
High Fat ◽  
Jnk Pathway

The oxidative stress-sensitive c-Jun-N-terminal kinase (JNK) pathway is known to be activated in diabetic condition and is involved in the progression of insulin resistance. However, the effect of antioxidants on JNK pathway and insulin resistance has not been investigated. The present study was aimed to investigate the effect of antioxidants on redox balance, insulin sensitivity, and JNK pathway in high-fat-fed rats. Male Wistar rats were divided into four groups: the control group – received a rodent chow; control+antioxidant group – fed with rodent chow supplemented with 0.2% (w/w) vitamin E, 0.3% (w/w) vitamin C, and 0.5% (w/w) α-lipoic acid; high-fat group – received high-fat diet; and high fat+antioxidant group – fed with high-fat diet supplemented with above antioxidants. Fat feeding to rats for 9 weeks significantly increased IRS-1 serine phoshorylation, reduced insulin-stimulated IRS-1 tyrosine phosphorylation and insulin sensitivity. High-fat diet also impaired redox balance and activated the redox-sensitive serine kinase – JNK pathway. Antioxidant supplementation along with high-fat diet preserved the free radical defense system, inhibited the activation of JNK pathway, and improved insulin signaling and insulin sensitivity. The present study shows for the first time that antioxidants inhibit JNK pathway and IRS-1 serine phosphorylation while improving insulin sensitivity in fat-fed rats. These findings implicate the beneficial effect of antioxidants in obesity-/dyslipidemia-induced insulin resistance in humans.

Long-term melatonin administration improves glucose homeostasis and insulin resistance state in high-fat-diet fed rats

2013 ◽  
Vol 8 (10) ◽  
pp. 958-967
Author(s):  
Xue-Dong Wan ◽  
San-Qiang Li ◽  
Shou-Min Xi ◽  
Jian-Fei Wang ◽  
Yan-Chun Guo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Insulin Resistance ◽  
Reactive Oxygen Species ◽  
Insulin Sensitivity ◽  
Glucose Homeostasis ◽  
Insulin Signaling ◽  
High Fat Diet ◽  
Metabolic Profiles ◽  
Oxygen Species ◽  
High Fat

AbstractEmerging evidence support an important role of reactive oxygen species in various forms of insulin resistance. It is identified that melatonin has antioxidant properties and prevents toxic effects of reactive oxygen species. In this study, we sought to assess the involvement of melatonin in the progression of insulin resistance in response to a high-fat diet (HFD) and to investigate the underlying mechanisms. Male rats were fed with a control diet, a high-fat diet, or a high-fat diet supplemented with melatonin (5 mg kg−1, i.p.) for 10 weeks. Glucose homeostasis, insulin sensitivity, antioxidative potency, and metabolic profiles in the rats were evaluated. Our results showed that a HFD led to increasing body mass, adipose tissue weight, plasma insulin, total cholesterol (TC), triglycerides (TG), free fatty acids (FFA), and decreased HDL-cholesterol (HDL-C) in rats. There was also a significant increase in the level of malondialdehyde (MDA) and decrease in superoxide dismutase (SOD) activity, oxidative stress markers both in the plasma and liver. An enhanced hepatic phosphoenolpyruvate carboxy-kinase (PEPCK) activity and RNA expression were observed. Impaired insulin signaling was evidenced by reducing insulin receptor substrate 2 (IRS2) tyrosine phosphorylation and protein kinase B (PKB) serine phosphorylation in response to insulin. Overactivation of stress-activated protein kinases JNK was also observed in the liver of HFD rats. However, simultaneous administration of melatonin to HFD rats significantly reduced oxidative stress in the system and liver, markedly improved impaired glucose homeostasis, insulin sensitivity, antioxidative potency, metabolic profiles and all the aforesaid adverse changes in HFD rats. Our results demonstrated that anti-oxidative property of melatonin is sufficient to ameliorate the insulin resistance condition, leading to the improvement of glucose homeostasis and the restoration of hepatic insulin signaling in a rat model of HFD-induced insulin resistance.

scholarly journals The Protective Effect of Fasudil on the Structure and Function of Cardiac Mitochondria from Rats with Type 2 Diabetes Induced by Streptozotocin with a High-Fat Diet Is Mediated by the Attenuation of Oxidative Stress

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Rong Guo ◽  
Baoxin Liu ◽  
Shunping Zhou ◽  
Buchun Zhang ◽  
Yawei Xu
Keyword(s):  
Oxidative Stress ◽  
High Fat Diet ◽  
Mitochondrial Permeability Transition ◽  
Myocardial Dysfunction ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Saline Control ◽  
Cardiac Mitochondria ◽  
High Fat ◽  
Rock Inhibitor

Dysfunction of cardiac mitochondria appears to play a substantial role in cardiomyopathy or myocardial dysfunction and is a promising therapeutic target for many cardiovascular diseases. We investigated the effect of the Rho/Rho-associated protein kinase (ROCK) inhibitor fasudil on cardiac mitochondria from rats in which diabetes was induced by a combination of streptozotocin (STZ) and a sustained high-fat diet. Eight weeks after diabetes was induced by a single intraperitoneal injection of 50 mg/kg STZ followed by a sustained high-fat diet, either fasudil (5 mg/kg bid) or equivalent volumes of saline (control) were administered over four weeks. Fasudil significantly protected against the histopathologic changes of cardiac mitochondria in diabetic rats. Fasudil significantly reduced the abundances of the Rho A, ROCK 1, and ROCK 2 proteins, restored the activities of succinate dehydrogenase (SDH) and monoamine oxidase (MAO) in cardiac mitochondria, inhibited the opening of the mitochondrial permeability transition pore, and decreased the total antioxidant capacity, as well as levels of malonyldialdehyde, hydroxy radical, reduced glutathione, and superoxide dismutase in heart. Fasudil improved the structures of cardiac mitochondria and increased both SDH and MAO activities in cardiac mitochondria. These beneficial effects may be associated with the attenuation of oxidative stress caused by fasudil treatment.

scholarly journals Dapagliflozin attenuates renal gluconeogenic enzyme expression in obese rats

2020 ◽  
Vol 245 (2) ◽  
pp. 193-205 ◽  
Author(s):  
Myat Theingi Swe ◽  
Laongdao Thongnak ◽  
Krit Jaikumkao ◽  
Anchalee Pongchaidecha ◽  
Varanuj Chatsudthipong ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Renal Function ◽  
Insulin Signaling ◽  
High Fat Diet ◽  
High Fat ◽  
Enzyme Expression ◽  
Renal Gluconeogenesis ◽  
Glucose Reabsorption ◽  
Obese Rats ◽  
Gluconeogenic Enzyme

The kidneys release glucose into the systemic circulation through glucose reabsorption and renal gluconeogenesis. Currently, the significance of renal glucose release in pathological conditions has become a subject of interest. We examined the effect of sodium-dependent glucose cotransporter 2 inhibitor (SGLT2i) on renal gluconeogenic enzyme expression in obese rats. Male Wistar rats (180–200 g) were fed either a normal diet (ND, n = 6) or a high-fat diet. At 16 weeks, after confirming the degree of glucose intolerance, high-fat diet-fed rats were randomly subdivided into three groups (n = 6/group): untreated group (HF), treated with dapagliflozin 1 mg/kg/day (HFSG) and treated with metformin 30 mg/kg/day (HFM). The treatment was continued for 4 weeks. We observed that dapagliflozin or metformin mitigated the enhanced expression of renal gluconeogenic enzymes, PEPCK, G6Pase and FBPase, as well as improved glucose tolerance and renal function in obese rats. Dapagliflozin downregulated the elevated expression of gluconeogenic transcription factors p-GSK3β, p-CREB and coactivator PGC1α in the renal cortical tissue. Metformin reduced the expression levels of renal cortical FOXO1 and CREB. Furthermore, reduced renal insulin signaling was improved and renal oxidative stress was attenuated by either dapagliflozin or metformin treatment in obese rats. We concluded that glucose tolerance was improved by dapagliflozin in obese prediabetic rats by suppressing renal glucose release from not only glucose reabsorption but also renal gluconeogenesis through improving renal cortical insulin signaling and oxidative stress. The efficacy of dapagliflozin in improving renal insulin signaling, oxidative stress and renal function was greater than that of metformin.

Hesperetin ameliorates hepatic oxidative stress and inflammation via the PI3K/AKT-Nrf2-ARE pathway in oleic acid-induced HepG2 cells and a rat model of high-fat diet-induced NAFLD

2021 ◽  
Author(s):  
Jingda Li ◽  
Tianqi Wang ◽  
Panpan Liu ◽  
Fuyuan Yang ◽  
Xudong Wang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Oleic Acid ◽  
Rat Model ◽  
High Fat Diet ◽  
Hepg2 Cells ◽  
Citrus Fruits ◽  
High Fat ◽  
Hepatic Oxidative Stress

Hesperetin as a major bioflavonoid in citrus fruits improves NAFLD by suppressing hepatic oxidative stress and inflammation.

scholarly journals High-fat diet-induced obesity and impairment of brain neurotransmitter pool

2020 ◽  
Vol 11 (1) ◽  
pp. 147-160
Author(s):  
Ranyah Shaker M. Labban ◽  
Hanan Alfawaz ◽  
Ahmed T. Almnaizel ◽  
Wail M. Hassan ◽  
Ramesa Shafi Bhat ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Brain Tissue ◽  
High Fat Diet ◽  
Density Lipoprotein ◽  
Obese Group ◽  
Control Group ◽  
High Fat ◽  
Brain Neurotransmitter ◽  
The Brain ◽  
Lean Group

AbstractObesity and the brain are linked since the brain can control the weight of the body through its neurotransmitters. The aim of the present study was to investigate the effect of high-fat diet (HFD)-induced obesity on brain functioning through the measurement of brain glutamate, dopamine, and serotonin metabolic pools. In the present study, two groups of rats served as subjects. Group 1 was fed a normal diet and named as the lean group. Group 2 was fed an HFD for 4 weeks and named as the obese group. Markers of oxidative stress (malondialdehyde, glutathione, glutathione-s-transferase, and vitamin C), inflammatory cytokines (interleukin [IL]-6 and IL-12), and leptin along with a lipid profile (cholesterol, triglycerides, high-density lipoprotein, and low-density lipoprotein levels) were measured in the serum. Neurotransmitters dopamine, serotonin, and glutamate were measured in brain tissue. Fecal samples were collected for observing changes in gut flora. In brain tissue, significantly high levels of dopamine and glutamate as well as significantly low levels of serotonin were found in the obese group compared to those in the lean group (P > 0.001) and were discussed in relation to the biochemical profile in the serum. It was also noted that the HFD affected bacterial gut composition in comparison to the control group with gram-positive cocci dominance in the control group compared to obese. The results of the present study confirm that obesity is linked to inflammation, oxidative stress, dyslipidemic processes, and altered brain neurotransmitter levels that can cause obesity-related neuropsychiatric complications.

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