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Project description:In addition to high intracellular glucose level, the diabetic state is also characterized by altered metabolites, which are pivotal regulators of glucotoxic pathways. In this study we analyzed Bezafibrate (BEZ) treated Streptozotocin (STZ) mice, which showed improved glucose metabolism compared to untreated STZ controls. In order to identify the key molecules and pathways, which participate in the beneficial effects of BEZ, we analyzed the skeletal muscle, white adipose tissue (WAT) and liver samples of BEZ-treated mice using non-targeted metabolomics (NMR spectroscopy), targeted metabolomics (mass spectrometry), microarrays and enzyme activity measurements with a particular focus on the liver. The analysis of muscle and WAT demonstrated that BEZ improved the expressions of genes and levels of metabolites, which could partly regulate the beneficial effects of BEZ on the glucose metabolism. Furthermore, in the liver, BEZ treatment reduced the elevated hepatic fumarate level of STZ mice, which was accompanied by a decreased expression of urea cycle genes. Since the urea cycle is involved in the production of fumarate, which is shown to be participated in glucotoxic pathways, our data suggest that BEZ could attenuate the urea cycle, reduce fumarate level and in turn ameliorate glucotoxicity in the liver of STZ mice
2022-03-08 | GSE179718 | GEO
Project description:In addition to high intracellular glucose level, the diabetic state is also characterized by altered metabolites, which are pivotal regulators of glucotoxic pathways. In this study we analyzed Bezafibrate (BEZ) treated Streptozotocin (STZ) mice, which showed improved glucose metabolism compared to untreated STZ controls. In order to identify the key molecules and pathways, which participate in the beneficial effects of BEZ, we analyzed the skeletal muscle, white adipose tissue (WAT) and liver samples of BEZ-treated mice using non-targeted metabolomics (NMR spectroscopy), targeted metabolomics (mass spectrometry), microarrays and enzyme activity measurements with a particular focus on the liver. The analysis of muscle and WAT demonstrated that BEZ improved the expressions of genes and levels of metabolites, which could partly regulate the beneficial effects of BEZ on the glucose metabolism. Furthermore, in the liver, BEZ treatment reduced the elevated hepatic fumarate level of STZ mice, which was accompanied by a decreased expression of urea cycle genes. Since the urea cycle is involved in the production of fumarate, which is shown to be participated in glucotoxic pathways, our data suggest that BEZ could attenuate the urea cycle, reduce fumarate level and in turn ameliorate glucotoxicity in the liver of STZ mice
2022-03-08 | GSE179717 | GEO
Project description:Bezafibrate reduces the elevated hepatic fumarate in insulin-deficient mice.
| PRJNA744754 | ENA
Project description:Bezafibrate reduces the elevated hepatic fumarate level in insulin-deficient streptozotocin mice [visceral adipose tissue]
| PRJNA744762 | ENA
Project description:Bezafibrate reduces the elevated hepatic fumarate level in insulin-deficient streptozotocin mice [skeletal muscle tissue]
| PRJNA744761 | ENA
Project description:ObjectiveRecently, we have shown that Bezafibrate (BEZ), the pan-PPAR (peroxisome proliferator-activated receptor) activator, ameliorated diabetes in insulin deficient streptozotocin treated diabetic mice. In order to study whether BEZ can also improve glucose metabolism in a mouse model for fatty liver and type 2 diabetes, the drug was applied to TallyHo mice.MethodsTallyHo mice were divided into an early (ED) and late (LD) diabetes progression group and both groups were treated with 0.5% BEZ (BEZ group) or standard diet (SD group) for 8 weeks. We analyzed plasma parameters, pancreatic beta-cell morphology, and mass as well as glucose metabolism of the BEZ-treated and control mice. Furthermore, liver fat content and composition as well as hepatic gluconeogenesis and mitochondrial mass were determined.ResultsPlasma lipid and glucose levels were markedly reduced upon BEZ treatment, which was accompanied by elevated insulin sensitivity index as well as glucose tolerance, respectively. BEZ increased islet area in the pancreas. Furthermore, BEZ treatment improved energy expenditure and metabolic flexibility. In the liver, BEZ ameliorated steatosis, modified lipid composition and increased mitochondrial mass, which was accompanied by reduced hepatic gluconeogenesis.ConclusionsOur data showed that BEZ ameliorates diabetes probably via reduced steatosis, enhanced hepatic mitochondrial mass, improved metabolic flexibility and elevated hepatic insulin sensitivity in TallyHo mice, suggesting that BEZ treatment could be beneficial for patients with NAFLD and impaired glucose metabolism.
| S-EPMC5323884 | biostudies-literature
Project description:Obesity and type 2 diabetes are associated with impaired mitochondrial function in adipose tissue. To study the effects of primary deficiency of mitochondrial energy metabolism in fat, we generated mice with adipose-specific deficiency of fumarate hydratase (FH), an integral Krebs cycle enzyme (AFHKO mice). AFHKO mice have severe ultrastructural abnormalities of mitochondria, ATP depletion in white adipose tissue (WAT) and brown adipose tissue, low WAT mass with small adipocytes, and impaired thermogenesis with large unilocular brown adipocytes. AFHKO mice are strongly protected against obesity, insulin resistance, and fatty liver despite aging and high-fat feeding. AFHKO white adipocytes showed normal lipolysis but low triglyceride synthesis. ATP depletion in normal white adipocytes by mitochondrial toxins also decreased triglyceride synthesis, proportionally to ATP depletion, suggesting that reduced triglyceride synthesis may result nonspecifically from adipocyte energy deficiency. At thermoneutrality, protection from insulin resistance and hepatic steatosis was diminished. Taken together, the results show that under the cold stress of regular animal room conditions, adipocyte-specific FH deficiency in mice causes mitochondrial energy depletion in adipose tissues and protects from obesity, hepatic steatosis, and insulin resistance, suggesting that in cold-stressed animals, mitochondrial function in adipose tissue is a determinant of fat mass and insulin sensitivity.
| S-EPMC5860441 | biostudies-literature
Project description:Insulin has anti-inflammatory effects in short-term experiments. However, the effects of chronic insulin administration on inflammation are unknown. We hypothesised that chronic insulin administration would beneficially alter adipose tissue inflammation and several circulating inflammatory markers.We administered two forms of long-acting insulin, insulin glargine (A21Gly,B31Arg,B32Arg human insulin) and insulin detemir (B29Lys[?-tetradecanoyl],desB30 human insulin), to LDL-receptor-deficient mice. After 8 weeks on a diet that causes obesity, hyperglycaemia, adipose tissue macrophage accumulation and atherosclerosis, the mice received subcutaneous glargine, detemir or NaCl (control) for 12 weeks. Serum amyloid A (SAA) and serum amyloid P (SAP), metabolic variables, adipose tissue macrophages and aortic atherosclerosis were evaluated.Weight gain was equivalent in all groups. The glycated haemoglobin level fell equivalently in both insulin-treated groups. Plasma cholesterol and triacylglycerol levels, and hepatic triacylglycerol level significantly improved in the glargine compared with the detemir or control groups. Levels of mRNA expression for monocyte chemotactic protein-1 and F4/80, a macrophage marker, in adipose tissue were decreased only in the glargine group (p?<?0.05). Visceral adipose tissue macrophage content decreased in both insulin groups (p?<?0.05), whereas atherosclerosis decreased only in the glargine group. Circulating SAA and SAP did not decrease in either insulin-treated group, but IL-6 levels fell in the glargine-treated mice.While chronic insulin administration did not decrease SAA and SAP, administration of glargine but not detemir insulin improved dyslipidaemia, IL-6 levels and atherosclerosis, and both insulins reduced macrophage accumulation in visceral adipose tissue. Thus, chronic insulin therapy has beneficial tissue effects independent of circulating inflammatory markers in this murine model of diet-induced obesity and diabetes.
| S-EPMC3246423 | biostudies-literature
Project description:Methionine sulfoxide reductase A (MsrA), a specific enzyme that converts methionine-S-sulfoxide to methionine, plays an important role in the regulation of protein function and the maintenance of redox homeostasis. In this study, we examined the impact of hepatic MsrA overexpression on lipid metabolism and atherosclerosis in apoE-deficient (apoE(-/-)) mice. In vitro study showed that in HepG2 cells, lentivirus-mediated human MsrA (hMsrA) overexpression upregulated the expression levels of several key lipoprotein-metabolism-related genes such as liver X receptor α, scavenger receptor class B type I, and ABCA1. ApoE(-/-) mice were intravenously injected with lentivirus to achieve high-level hMsrA expression predominantly in the liver. We found that hepatic hMsrA expression significantly reduced plasma VLDL/LDL levels, improved plasma superoxide dismutase, and paraoxonase-1 activities, and decreased plasma serum amyloid A level in apoE(-/-) mice fed a Western diet, by significantly altering the expression of several genes in the liver involving cholesterol selective uptake, conversion and excretion into bile, TG biosynthesis, and inflammation. Moreover, overexpression of hMsrA resulted in reduced hepatic steatosis and aortic atherosclerosis. These results suggest that hepatic MsrA may be an effective therapeutic target for ameliorating dyslipidemia and reducing atherosclerosis-related cardiovascular diseases.
| S-EPMC4583078 | biostudies-literature
Project description:The prevalence of nonalcoholic fatty liver disease (NAFLD) is increasing in parallel with the prevalence of obesity. DNA damage-inducible protein 34 (GADD34/Ppp1r15a), originally isolated from UV-inducible transcripts in Chinese hamster ovary (CHO) cells, dephosphorylates several kinases that function in important signaling cascades, including dephosphorylation of eIF2α. We examined the effects of GADD34 on natural life span by using GADD34-deficient mice. Here we observed for the first time that with age GADD34-deficient mice become obese, developing fatty liver followed by liver cirrhosis, hepatocellular carcinoma, and insulin resistance. We found that myofibroblasts and immune cells infiltrated the portal veins of aged GADD34-deficient mouse livers. A high-fat diet (HFD) induced a higher level of steatosis in young GADD34-deficient mice compared with WT mice. Differentiation into fat is dependent on insulin signaling. Insulin signaling in young GADD34-deficient mice was higher than that in WT mice, which explained the higher fat differentiation of mouse embryonic fibroblasts (MEFs) observed in GADD34-deficient mice. Through aging or a HFD, insulin signaling in GADD34-deficient liver converted to be down regulated compared with WT mice. We found that a HFD or palmitate treatment converted insulin signaling by up-regulating TNF-α and JNK.
| S-EPMC4551985 | biostudies-literature