scholarly journals Developmental Programming: Differential Effects of Prenatal Testosterone Excess on Insulin Target Tissues

2010 ◽  
Vol 31 (5) ◽  
pp. 775-775
Author(s):  
Shadia E. Nada ◽  
Robert C. Thompson ◽  
Vasantha Padmanabhan
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Insulin Receptor ◽  
Glycogen Synthase ◽  
Hormone Sensitive Lipase ◽  
Initiation Factor ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Peripheral Tissues ◽  
Prenatal Testosterone

Polycystic ovarian syndrome (PCOS) is the leading cause of infertility in reproductive-aged women with the majority manifesting insulin resistance. To delineate the causes of insulin resistance in women with PCOS, we determined changes in the mRNA expression of insulin receptor (IR) isoforms and members of its signaling pathway in tissues of adult control (n = 7) and prenatal testosterone (T)-treated (n = 6) sheep (100 mg/kg twice a week from d 30-90 of gestation), the reproductive/metabolic characteristics of which are similar to women with PCOS. Findings revealed that prenatal T excess reduced (P < 0.05) expression of IR-B isoform (only isoform detected), insulin receptor substrate-2 (IRS-2), protein kinase B (AKt), peroxisome proliferator-activated receptor-γ (PPARγ), hormone-sensitive lipase (HSL), and mammalian target of rapamycin (mTOR) but increased expression of rapamycin-insensitive companion of mTOR (rictor), and eukaryotic initiation factor 4E (eIF4E) in the liver. Prenatal T excess increased (P < 0.05) the IR-A to IR-B isoform ratio and expression of IRS-1, glycogen synthase kinase-3α and -β (GSK-3α and -β), and rictor while reducing ERK1 in muscle. In the adipose tissue, prenatal T excess increased the expression of IRS-2, phosphatidylinositol 3-kinase (PI3K), PPARγ, and mTOR mRNAs. These findings provide evidence that prenatal T excess modulates in a tissue-specific manner the expression levels of several genes involved in mediating insulin action. These changes are consistent with the hypothesis that prenatal T excess disrupts the insulin sensitivity of peripheral tissues, with liver and muscle being insulin resistant and adipose tissue insulin sensitive.

scholarly journals Developmental Programming: Differential Effects of Prenatal Testosterone Excess on Insulin Target Tissues

Endocrinology ◽  
2010 ◽  
Vol 151 (11) ◽  
pp. 5165-5173 ◽  
Author(s):  
Shadia E. Nada ◽  
Robert C. Thompson ◽  
Vasantha Padmanabhan
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Insulin Receptor ◽  
Glycogen Synthase ◽  
Hormone Sensitive Lipase ◽  
Initiation Factor ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Peripheral Tissues ◽  
Prenatal Testosterone

Polycystic ovarian syndrome (PCOS) is the leading cause of infertility in reproductive-aged women with the majority manifesting insulin resistance. To delineate the causes of insulin resistance in women with PCOS, we determined changes in the mRNA expression of insulin receptor (IR) isoforms and members of its signaling pathway in tissues of adult control (n = 7) and prenatal testosterone (T)-treated (n = 6) sheep (100 mg/kg twice a week from d 30–90 of gestation), the reproductive/metabolic characteristics of which are similar to women with PCOS. Findings revealed that prenatal T excess reduced (P < 0.05) expression of IR-B isoform (only isoform detected), insulin receptor substrate-2 (IRS-2), protein kinase B (AKt), peroxisome proliferator-activated receptor-γ (PPARγ), hormone-sensitive lipase (HSL), and mammalian target of rapamycin (mTOR) but increased expression of rapamycin-insensitive companion of mTOR (rictor), and eukaryotic initiation factor 4E (eIF4E) in the liver. Prenatal T excess increased (P < 0.05) the IR-A to IR-B isoform ratio and expression of IRS-1, glycogen synthase kinase-3α and -β (GSK-3α and -β), and rictor while reducing ERK1 in muscle. In the adipose tissue, prenatal T excess increased the expression of IRS-2, phosphatidylinositol 3-kinase (PI3K), PPARγ, and mTOR mRNAs. These findings provide evidence that prenatal T excess modulates in a tissue-specific manner the expression levels of several genes involved in mediating insulin action. These changes are consistent with the hypothesis that prenatal T excess disrupts the insulin sensitivity of peripheral tissues, with liver and muscle being insulin resistant and adipose tissue insulin sensitive.

Abstract 15931: Glycogen Synthase Kinase-3α Plays a Critical Role in the Development of Cardiac Dysfunction During Obesity and Insulin Resistance Through Phosphorylation of Peroxisome Proliferator-Activated Receptor α

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Michinari Nakamura ◽  
Peiyong Zhai ◽  
Junichi Sadoshima
Keyword(s):  
Insulin Resistance ◽  
Cardiac Hypertrophy ◽  
Diastolic Dysfunction ◽  
Cardiac Dysfunction ◽  
Lipid Accumulation ◽  
Glycogen Synthase ◽  
Critical Role ◽  
Cardiac Metabolism ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor

Obesity and insulin resistance (IR) lead to impaired cardiac metabolism, resulting in cardiac dysfunction. However, the underlying mechanisms responsible for the development of cardiac dysfunction remain poorly understood. PPARα serves as a key regulator of fatty acid (FA) metabolism in the heart. GSK-3α, a serine/threonine kinase, was dephosphorylated at S21 and activated (2.0 fold, p<0.05) in the hearts of obese mice fed a high-fat diet (HFD) and ob/ob mice. To evaluate the functional significance of GSK-3α upregulation, wild-type (WT) and cardiac specific GSK-3α heterozygous knockout (cGSK-3α HKO) mice were fed a HFD for up to 14 weeks. There was no difference in the food intake or body weight change between WT and cGSK-3α HKO mice. However, cardiac hypertrophy and diastolic dysfunction observed in WT mice were significantly ameliorated in cGSK-3α HKO mice after HFD feeding (8.1± 0.6 and 6.5±0.5, LVW/TL; 24.8±0.9 and 16.6±0.8, deceleration time (DT), all p<0.05). FA oxidation (FAO) (0.81 fold) and ectopic lipid accumulation (Oil Red O staining) were significantly decreased in cGSK-3α HKO mice than in WT mice after HFD feeding. GSK-3α, but not GSK-3β, directly interacted with and phosphorylated PPARα at the ligand binding domain in cardiomyocytes (CMs) and in the heart. PPARα phosphorylation in the heart was significantly increased (2.1 fold, p<0.05) in response to HFD, but it was attenuated in cGSK-3α HKO mice (0.74 fold, p<0.05). Fenofibrate, a PPARα ligand, inhibited GSK-3α-induced PPARα phosphorylation (0.81 fold, p<0.05), reduced ectopic lipid accumulation, FAO (0.84 fold, p<0.05), and attenuated diastolic dysfunction (25.5±3.1 and 18.6±2.5, DT; 0.16±0.04 and 0.08±0.02, EDPVR, all p<0.05) in the heart of HFD fed mice. Collectively, these results suggest that GSK-3α increases PPARα activity through phosphorylation of PPARα, which is inhibited by Fenofibrate. Activation of GSK-3α and consequent phosphorylation of PPARα during obesity and IR could play an important role in the development of cardiac hypertrophy and diastolic dysfunction. Synthetic PPARα ligands inhibit GSK-3α-mediated phosphorylation of PPARα, thereby paradoxically attenuating excessive FA metabolism in cardiomyocytes.

scholarly journals Peroxisome Proliferator-Activated Receptor γ and Adipose Tissue—Understanding Obesity-Related Changes in Regulation of Lipid and Glucose Metabolism

2006 ◽  
Vol 92 (2) ◽  
pp. 386-395 ◽  
Author(s):  
Arya M. Sharma ◽  
Bart Staels
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Metabolic Syndrome ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Endocrine Function ◽  
Low Grade ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor

Abstract Context: Adipose tissue is a metabolically dynamic organ, serving as a buffer to control fatty acid flux and a regulator of endocrine function. In obese subjects, and those with type 2 diabetes or the metabolic syndrome, adipose tissue function is altered (i.e. adipocytes display morphological differences alongside aberrant endocrine and metabolic function and low-grade inflammation). Evidence Acquisition: Articles on the role of peroxisome proliferator-activated receptor γ (PPARγ) in adipose tissue of healthy individuals and those with obesity, metabolic syndrome, or type 2 diabetes were sourced using MEDLINE (1990–2006). Evidence Synthesis: Articles were assessed to provide a comprehensive overview of how PPARγ-activating ligands improve adipose tissue function, and how this links to improvements in insulin resistance and the progression to type 2 diabetes and atherosclerosis. Conclusions: PPARγ is highly expressed in adipose tissue, where its activation with thiazolidinediones alters fat topography and adipocyte phenotype and up-regulates genes involved in fatty acid metabolism and triglyceride storage. Furthermore, PPARγ activation is associated with potentially beneficial effects on the expression and secretion of a range of factors, including adiponectin, resistin, IL-6, TNFα, plasminogen activator inhibitor-1, monocyte chemoattractant protein-1, and angiotensinogen, as well as a reduction in plasma nonesterified fatty acid supply. The effects of PPARγ also extend to macrophages, where they suppress production of inflammatory mediators. As such, PPARγ activation appears to have a beneficial effect on the relationship between the macrophage and adipocyte that is distorted in obesity. Thus, PPARγ-activating ligands improve adipose tissue function and may have a role in preventing progression of insulin resistance to diabetes and endothelial dysfunction to atherosclerosis.

scholarly journals Unripe Rubus coreanus Miquel Extract Containing Ellagic Acid Promotes Lipolysis and Thermogenesis In Vitro and In Vivo

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5954
Author(s):  
Kyeong Jo Kim ◽  
Eui-Seon Jeong ◽  
Ki Hoon Lee ◽  
Ju-Ryun Na ◽  
Soyi Park ◽  
...  
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Ellagic Acid ◽  
Uncoupling Protein ◽  
Hormone Sensitive Lipase ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Rubus Coreanus ◽  
Associated Proteins

Previously, we demonstrated that a 5% ethanol extract of unripe Rubus coreanus (5-uRCK) and ellagic acid has hypocholesterolemic and antiobesity activity, at least partially mediated by the downregulation of adipogenic and lipogenic gene expression in high-fat diet (HFD)-fed animals. The present study investigated the thermogenic and lipolytic antiobesity effects of 5-uRCK and ellagic acid in HFD-induced obese C57BL/6 mice and explored its mechanism of action. Mice fed an HFD received 5-uRCK or ellagic acid as a post-treatment or pretreatment. Both post-treated and pretreated mice showed significant reductions in body weight and adipose tissue mass compared to the HFD-fed mice. The protein levels of lipolysis-associated proteins, such as adipose triglyceride lipase (ATGL), phosphorylated hormone-sensitive lipase (p-HSL), and perilipin1 (PLIN1), were significantly increased in both the 5-uRCK- and ellagic acid-treated mouse epididymal white adipose tissue (eWAT). Additionally, thermogenesis-associated proteins, such as peroxisome proliferator-activated receptor α (PPARα), carnitine palmitoyl transferase-1 (CPT1), uncoupling protein 1 (UCP1), and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α), in inguinal white adipose tissue (ingWAT) were clearly increased in both the 5-uRCK- and ellagic acid-treated mice compared to HFD-fed mice. These results suggest that 5-uRCK and ellagic acid are effective for suppressing body weight gain and enhancing the lipid profile.

scholarly journals Whey Peptides Stimulate Differentiation and Lipid Metabolism in Adipocytes and Ameliorate Lipotoxicity-Induced Insulin Resistance in Muscle Cells

Nutrients ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 425 ◽  
Author(s):  
Kenneth D’Souza ◽  
Angella Mercer ◽  
Hannah Mawhinney ◽  
Thomas Pulinilkunnil ◽  
Chibuike C. Udenigwe ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Lipid Metabolism ◽  
Milk Proteins ◽  
C2c12 Myotubes ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Systemic Insulin Resistance ◽  
Skeletal Myotubes

Deregulation of lipid metabolism and insulin function in muscle and adipose tissue are hallmarks of systemic insulin resistance, which can progress to type 2 diabetes. While previous studies suggested that milk proteins influence systemic glucose homeostasis and insulin function, it remains unclear whether bioactive peptides generated from whey alter lipid metabolism and its accumulation in muscle and adipose tissue. Therefore, we incubated murine 3T3-L1 preadipocytes and C2C12 myotubes with a whey peptide mixture produced through pepsin-pancreatin digestion, mimicking peptides generated in the gut from whey protein hydrolysis, and examined its effect on indicators of lipid metabolism and insulin sensitivity. Whey peptides, particularly those derived from bovine serum albumin (BSA), promoted 3T3-L1 adipocyte differentiation and triacylglycerol (TG) accumulation in accordance with peroxisome proliferator-activated receptor γ (PPARγ) upregulation. Whey/BSA peptides also increased lipolysis and mitochondrial fat oxidation in adipocytes, which was associated with the upregulation of peroxisome proliferator-activated receptor δ (PPARδ). In C2C12 myotubes, whey but not BSA peptides ameliorated palmitate-induced insulin resistance, which was associated with reduced inflammation and diacylglycerol accumulation, and increased sequestration of fatty acids in the TG pool. Taken together, our study suggests that whey peptides generated via pepsin-pancreatin digestion profoundly alter lipid metabolism and accumulation in adipocytes and skeletal myotubes.

scholarly journals The effects of obesity-associated insulin resistance on mRNA expression of peroxisome proliferator-activated receptor-γ target genes, in dogs

2007 ◽  
Vol 98 (3) ◽  
pp. 497-503 ◽  
Author(s):  
Constance Gayet ◽  
Veronique Leray ◽  
Masayuki Saito ◽  
Brigitte Siliart ◽  
Patrick Nguyen
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Mrna Expression ◽  
Target Genes ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Glucose And Lipid Metabolism ◽  
Visceral Adipose

Visceral adipose tissue and skeletal muscle have central roles in determining whole-body insulin sensitivity. The peroxisome proliferator-activated receptor-γ (PPARγ) is a potential mediator of insulin sensitivity. It can directly modulate the expression of genes that are involved in glucose and lipid metabolism, including GLUT4, lipoprotein lipase (LPL) and adipocytokines (leptin and adiponectin). In this study, we aimed to determine the effects of obesity-associated insulin resistance on mRNA expression of PPARγ and its target genes. Dogs were studied when they were lean and at the end of an overfeeding period when they had reached a steady obese state. The use of a sensitive, real-time PCR assay allowed a relative quantification of mRNA expression for PPARγ, LPL, GLUT4, leptin and adiponectin, in adipose tissue and skeletal muscle. In visceral adipose tissue and/or skeletal muscle, mRNA expression of PPARγ, LPL and GLUT4 were at least 2-fold less in obese and insulin-resistant dogs compared with the same animals when they were lean and insulin-sensitive. The mRNA expression and plasma concentration of leptin was increased, whereas the plasma level and mRNA expression of adiponectin was decreased, by obesity. In adipose tissue, PPARγ expression was correlated with leptin and adiponectin. These findings, in an original model of obesity induced by a prolonged period of overfeeding, showed that insulin resistance is associated with a decrease in PPARγ mRNA expression that could dysregulate expression of several genes involved in glucose and lipid metabolism.

scholarly journals Adipogenesis and lipotoxicity: role of peroxisome proliferator-activated receptor γ (PPARγ) and PPARγcoactivator-1 (PGC1)

2007 ◽  
Vol 10 (10A) ◽  
pp. 1132-1137 ◽  
Author(s):  
Gema Medina-Gomez ◽  
Sarah Gray ◽  
Antonio Vidal-Puig
Keyword(s):  
Insulin Resistance ◽  
Fatty Acids ◽  
Adipose Tissue ◽  
Peroxisome Proliferator ◽  
Metabolic Complications ◽  
Peroxisome Proliferator Activated Receptor ◽  
Toxic Response ◽  
Increased Risk ◽  
And Function

AbstractObesity is characterised by an increase in the adipose deposits, resulting from an imbalance between food intake and energy expenditure. When expansion of the adipose tissue reaches its maximum limit, as in obesity, fat accumulates in non-adipose tissues such as liver, heart, muscle and pancreas, developing a toxic response known as lipotoxicity, a condition that promotes the development of insulin resistance and other metabolic complications. Thus, the lipotoxic state may contribute to the increased risk of insulin resistance, diabetes, fatty liver and cardiovascular complications associated with obesity.We are interested in studying adipose tissue, specifically how mechanisms of adipogenesis and remodelling of adipose tissue, in terms of size and function of the adipocytes, could be considered a strategy to increase the capacity for lipid storage and prevent lipotoxicity. The peroxisome proliferator-activated receptors (PPARs) are a family of transcription factors that regulate energy balance by promoting either energy deposition or energy dissipation. Under normal physiological conditions, PPARγ is mainly expressed in adipose tissue and regulates diverse functions such as the development of fat cells and their capacity to store lipids. The generation of PPARγ knockout mice, either tissue specific or isoform specific, has provided new models to study PPARγ’s role in adipose tissue differentiation and function and have highlighted the essential role of PPARγ in adipogenesis and lipogenesis.A second strategy to prevent lipotoxicity is to increase the capacity of tissues to oxidise fatty acids. PPARγcoactivator-1α is a coactivator of PPARγ that induces the expression of genes that promote the differentiation of preadipocytes to brown adipocytes. Recently, it has been implicated in increasing the oxidation of fatty acids via increasing mitochondrial capacity and function, making this co-factor a key candidate for the treatment of lipotoxicity.

Sign in / Sign up

Export Citation Format

Share Document