scholarly journals Hexarelin Signaling to PPARγin Metabolic Diseases

PPAR Research ◽  
2008 ◽  
Vol 2008 ◽  
pp. 1-9 ◽  
Author(s):  
Annie Demers ◽  
Amélie Rodrigue-Way ◽  
André Tremblay
Keyword(s):  
Transcriptional Control ◽  
Energy Homeostasis ◽  
Metabolic Diseases ◽  
Scavenger Receptor ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Insulin Sensitizer ◽  
Metabolic Functions ◽  
Growth Hormone Releasing Peptides ◽  
The Impact

Investigating the metabolic functions of the nuclear receptor peroxisome proliferator-activated receptorγ(PPARγ) has been extremely rewarding over the past years. Uncovering the biologic roles of PPARγand its mechanism of action has greatly advanced our understanding of the transcriptional control of lipid and glucose metabolism, and compounds such as thiazolidinediones which directly regulate PPARγhave proven to exhibit potent insulin-sensitizer effects in the treatment of diabetes. We review here recent advances on the emerging role of growth hormone releasing peptides in regulating PPARγthrough interaction with scavenger receptor CD36 and ghrelin GHS-R1a receptor. With the impact that these peptides exert on the metabolic pathways involved in lipid metabolism and energy homeostasis, it is hoped that the development of novel approaches in the regulation of PPAR functions will bring additional therapeutic possibilities to face problems related to metabolic diseases.

scholarly journals Reducing 14-3-3ζ expression influences adipocyte maturity and impairs function

2020 ◽  
Vol 319 (1) ◽  
pp. E117-E132
Author(s):  
Abel K. Oppong ◽  
Kadidia Diallo ◽  
Isabelle Robillard Frayne ◽  
Christine Des Rosiers ◽  
Gareth E. Lim
Keyword(s):  
Binding Sites ◽  
De Novo ◽  
Hormone Sensitive Lipase ◽  
Peroxisome Proliferator ◽  
Mature Adipocyte ◽  
Peroxisome Proliferator Activated Receptor ◽  
Triacylglycerol Lipase ◽  
Metabolic Functions ◽  
Negative Effect ◽  
The Impact

One of the primary metabolic functions of a mature adipocyte is to supply energy via lipolysis, or the catabolism of stored lipids. Adipose triacylglycerol lipase (ATGL) and hormone-sensitive lipase (HSL) are critical lipolytic enzymes, and their phosphorylation generates phospho-binding sites for 14-3-3 proteins, a ubiquitously expressed family of molecular scaffolds. Although we previously identified essential roles of the 14-3-3ζ isoform in murine adipogenesis, the presence of 14-3-3 protein binding sites on ATGL and HSL suggests that 14-3-3ζ could also influence mature adipocyte processes like lipolysis. Here we demonstrate that 14-3-3ζ is necessary for lipolysis in male mice and fully differentiated 3T3-L1 adipocytes, as depletion of 14-3-3ζ significantly impaired glycerol and free fatty acid (FFA) release. Unexpectedly, reducing 14-3-3ζ expression was found to significantly impact adipocyte maturity, as observed by reduced abundance of peroxisome proliferator-activated receptor (PPAR)γ2 protein and expression of mature adipocyte genes and those associated with de novo triglyceride synthesis and lipolysis. The impact of 14-3-3ζ depletion on adipocyte maturity was further examined with untargeted lipidomics, which revealed that reductions in 14-3-3ζ abundance promoted the acquisition of a lipidomic signature that resembled undifferentiated preadipocytes. Collectively, these findings reveal a novel aspect of 14-3-3ζ in adipocytes, as reducing 14-3-3ζ was found to have a negative effect on adipocyte maturity and adipocyte-specific processes like lipolysis.

scholarly journals Dietary fructose aggravates the pathobiology of traumatic brain injury by influencing energy homeostasis and plasticity

2015 ◽  
Vol 36 (5) ◽  
pp. 941-953 ◽  
Author(s):  
Rahul Agrawal ◽  
Emily Noble ◽  
Laurent Vergnes ◽  
Zhe Ying ◽  
Karen Reue ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Energy Homeostasis ◽  
Metabolic Diseases ◽  
Brain Plasticity ◽  
Phenotypic Expression ◽  
Membrane Lipid ◽  
Sirtuin 1 ◽  
Peroxisome Proliferator ◽  
The Impact

Fructose consumption has been on the rise for the last two decades and is starting to be recognized as being responsible for metabolic diseases. Metabolic disorders pose a particular threat for brain conditions characterized by energy dysfunction, such as traumatic brain injury. Traumatic brain injury patients experience sudden abnormalities in the control of brain metabolism and cognitive function, which may worsen the prospect of brain plasticity and function. The mechanisms involved are poorly understood. Here we report that fructose consumption disrupts hippocampal energy homeostasis as evidenced by a decline in functional mitochondria bioenergetics (oxygen consumption rate and cytochrome C oxidase activity) and an aggravation of the effects of traumatic brain injury on molecular systems engaged in cell energy homeostasis (sirtuin 1, peroxisome proliferator-activated receptor gamma coactivator-1alpha) and synaptic plasticity (brain-derived neurotrophic factor, tropomyosin receptor kinase B, cyclic adenosine monophosphate response element binding, synaptophysin signaling). Fructose also worsened the effects of traumatic brain injury on spatial memory, which disruption was associated with a decrease in hippocampal insulin receptor signaling. Additionally, fructose consumption and traumatic brain injury promoted plasma membrane lipid peroxidation, measured by elevated protein and phenotypic expression of 4-hydroxynonenal. These data imply that high fructose consumption exacerbates the pathology of brain trauma by further disrupting energy metabolism and brain plasticity, highlighting the impact of diet on the resilience to neurological disorders.

scholarly journals Hepatocyte-specific, PPARγ-regulated mechanisms to promote steatosis in adult mice

2017 ◽  
Vol 232 (1) ◽  
pp. 107-121 ◽  
Author(s):  
Abigail Wolf Greenstein ◽  
Neena Majumdar ◽  
Peng Yang ◽  
Papasani V Subbaiah ◽  
Rhonda D Kineman ◽  
...  
Keyword(s):  
Metabolic Diseases ◽  
De Novo ◽  
Peroxisome Proliferator ◽  
Systemic Delivery ◽  
Improve Insulin Sensitivity ◽  
High Fat ◽  
Peroxisome Proliferator Activated Receptor ◽  
Adult Mice ◽  
Specific Effects ◽  
The Impact

Peroxisome proliferator-activated receptor γ (PPARγ) is the target for thiazolidinones (TZDs), drugs that improve insulin sensitivity and fatty liver in humans and rodent models, related to a reduction in hepatic de novo lipogenesis (DNL). The systemic effects of TZDs are in contrast to reports suggesting hepatocyte-specific activation of PPARγ promotes DNL, triacylglycerol (TAG) uptake and fatty acid (FA) esterification. As these hepatocyte-specific effects of PPARγ could counterbalance the positive therapeutic actions of systemic delivery of TZDs, the current study used a mouse model of adult-onset, liver (hepatocyte)-specific PPARγ knockdown (aLivPPARγkd). This model has advantages over existing congenital knockout models, by avoiding compensatory changes related to embryonic knockdown, thus better modeling the impact of altering PPARγ on adult physiology, where metabolic diseases most frequently develop. The impact of aLivPPARγkd on hepatic gene expression and endpoints in lipid metabolism was examined after 1 or 18 weeks (Chow-fed) or after 14 weeks of low- or high-fat (HF) diet. aLivPPARγkd reduced hepatic TAG content but did not impact endpoints in DNL or TAG uptake. However, aLivPPARγkd reduced the expression of the FA translocase (Cd36), in 18-week Chow- and HF-fed mice, associated with increased NEFA after HF feeding. Also, aLivPPARγkd dramatically reduced Mogat1 expression, that was reflected by an increase in hepatic monoacylglycerol (MAG) levels, indicative of reduced MOGAT activity. These results, coupled with previous reports, suggest that Cd36-mediated FA uptake and MAG pathway-mediated FA esterification are major targets of hepatocyte PPARγ, where loss of this control explains in part the protection against steatosis observed after aLivPPARγkd.

The emerging role of COX-2, 15-LOX, and PPARγ in metabolic diseases and cancer: An introduction to novel multi-target directed ligands (MTDLs)

2020 ◽  
Vol 27 ◽  
Author(s):  
Rana A. Alaaeddine ◽  
Perihan A. Elzahhar ◽  
Ibrahim AlZaim ◽  
Wassim Abou-Kheir ◽  
Ahmed S.F. Belal ◽  
...  
Keyword(s):  
Metabolic Diseases ◽  
Biological Effects ◽  
Arachidonic Acid Metabolism ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Cellular Targets ◽  
Design And Synthesis ◽  
Early Results ◽  
Cox 2

: Emerging evidence supports an intertwining framework for the involvement of different inflammatory pathways in a common pathological background for a number of disorders. Of importance are pathways involving arachidonic acid metabolism by cyclooxygenase-2 (COX-2) and 15-lipoxygenase (15-LOX). Both enzyme activities and their products are implicated in a range of pathophysiological processes encompassing metabolic impairment leading to adipose inflammation and the subsequent vascular and neurological disorders, in addition to various pro-and anti-tumorigenic effects. A further layer of complexity is encountered by the disparate, and often reciprocal, modulatory effect COX-2 and 15-LOX activities and metabolites exert on each other or on other cellular targets, the most prominent of which is peroxisome proliferator-activated receptor gamma (PPARγ). Thus, effective therapeutic intervention with such multifaceted disorders requires the simultaneous modulation of more than one target. Here, we describe the role of COX-2, 15-LOX, and PPARγ in cancer and complications of metabolic disorders, highlight the value of designing multi-target directed ligands (MTDLs) modifying their activity, and summarize the available literature regarding the rationale and feasibility of design and synthesis of these ligands together with their known biological effects. We speculate on the potential impact of MTDLs in these disorders as well as emphasize the need for structured future effort to translate these early results facilitating the adoption of these, and similar, molecules in clinical research.

scholarly journals The Impact of Anthocyanins and Iridoids on Transcription Factors Crucial for Lipid and Cholesterol Homeostasis

2021 ◽  
Vol 22 (11) ◽  
pp. 6074
Author(s):  
Maciej Danielewski ◽  
Agnieszka Matuszewska ◽  
Adam Szeląg ◽  
Tomasz Sozański
Keyword(s):  
Transcription Factors ◽  
Cholesterol Metabolism ◽  
Binding Protein ◽  
Regulatory Element ◽  
Cholesterol Homeostasis ◽  
Lipid Lowering ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Cell Functions ◽  
The Impact

Nutrition determines our health, both directly and indirectly. Consumed foods affect the functioning of individual organs as well as entire systems, e.g., the cardiovascular system. There are many different diets, but universal guidelines for proper nutrition are provided in the WHO healthy eating pyramid. According to the latest version, plant products should form the basis of our diet. Many groups of plant compounds with a beneficial effect on human health have been described. Such groups include anthocyanins and iridoids, for which it has been proven that their consumption may lead to, inter alia, antioxidant, cholesterol and lipid-lowering, anti-obesity and anti-diabetic effects. Transcription factors directly affect a number of parameters of cell functions and cellular metabolism. In the context of lipid and cholesterol metabolism, five particularly important transcription factors can be distinguished: liver X receptor (LXR), peroxisome proliferator-activated receptor-α (PPAR-α), peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer binding protein α (C/EBPα) and sterol regulatory element-binding protein 1c (SREBP-1c). Both anthocyanins and iridoids may alter the expression of these transcription factors. The aim of this review is to collect and systematize knowledge about the impact of anthocyanins and iridoids on transcription factors crucial for lipid and cholesterol homeostasis.

scholarly journals Zidovudine Impairs Adipogenic Differentiation through Inhibition of Clonal Expansion

2008 ◽  
Vol 52 (8) ◽  
pp. 2882-2889 ◽  
Author(s):  
Metodi V. Stankov ◽  
Reinhold E. Schmidt ◽  
Georg M. N. Behrens
Keyword(s):  
Adipogenic Differentiation ◽  
Clonal Expansion ◽  
Inhibitory Effect ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Triglyceride Accumulation ◽  
Thymidine Incorporation Assay ◽  
Human Preadipocytes ◽  
Incorporation Assay ◽  
The Impact

ABSTRACT Lipoatrophy is a prevalent side effect of treatment with thymidine analogues. We wished to confine the time point of the antiadipogenic effect of zidovudine (AZT) during adipogenesis and to evaluate the antiproliferative effect of AZT on adipocyte homeostasis. We investigated the effects of AZT on adipogenesis in 3T3-F442A cells and studied their proliferation, differentiation, viability, and adiponectin expression. Cells were exposed to AZT (1 μM, 3 μM, 6 μM, and 180 μM), stavudine (d4T; 3 μM), or dideoxycytosine (ddC; 0.1 μM) for up to 15 days. Differentiation was assessed by real-time PCR and quantification of triglyceride accumulation. Proliferation and clonal expansion were determined by a [3H]thymidine incorporation assay. When they were induced to differentiate in the presence of AZT at the maximum concentration in plasma (C max) and lower concentrations, 3T3-F442A preadipocytes failed to accumulate cytoplasmic triacylglycerol and failed to express normal levels of the later adipogenic transcription factors, CCAAT/enhancer-binding protein α and peroxisome proliferator-activated receptor γ. AZT exerted an inhibitory effect on the completion of the mitotic clonal expansion, which resulted in incomplete 3T3-F442A differentiation and, finally, a reduction in the level of adiponectin expression. In addition, AZT impaired the constitutive proliferation in murine and primary human subcutaneous preadipocytes. In contrast, incubation with d4T and ddC at the C max did not affect either preadipocyte proliferation or clonal expansion and differentiation. We conclude that the antiproliferative and antiadipogenetic effects of AZT on murine and primary human preadipocytes reveal the impact of the drug on fat tissue regeneration. These effects of the drug are expected to contribute to disturbed adipose tissue homeostasis and to be influenced by differential drug concentration and penetration in individual patients.

A Tale of Two Diseases: Exploring Mechanisms Linking Diabetes Mellitus with Alzheimer’s Disease

2021 ◽  
pp. 1-17
Author(s):  
Jessica Lynn ◽  
Mingi Park ◽  
Christiana Ogunwale ◽  
George K. Acquaah-Mensah
Keyword(s):  
Diabetes Mellitus ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Glycogen Synthase ◽  
Mammalian Target Of Rapamycin ◽  
Insulin Receptors ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Main Component ◽  
The Impact

Dementias, including the type associated with Alzheimer’s disease (AD), are on the rise worldwide. Similarly, type 2 diabetes mellitus (T2DM) is one of the most prevalent chronic diseases globally. Although mechanisms and treatments are well-established for T2DM, there remains much to be discovered. Recent research efforts have further investigated factors involved in the etiology of AD. Previously perceived to be unrelated diseases, commonalities between T2DM and AD have more recently been observed. As a result, AD has been labeled as “type 3 diabetes”. In this review, we detail the shared processes that contribute to these two diseases. Insulin resistance, the main component of the pathogenesis of T2DM, is also present in AD, causing impaired brain glucose metabolism, neurodegeneration, and cognitive impairment. Dysregulation of insulin receptors and components of the insulin signaling pathway, including protein kinase B, glycogen synthase kinase 3β, and mammalian target of rapamycin are reported in both diseases. T2DM and AD also show evidence of inflammation, oxidative stress, mitochondrial dysfunction, advanced glycation end products, and amyloid deposition. The impact that changes in neurovascular structure and genetics have on the development of these conditions is also being examined. With the discovery of factors contributing to AD, innovative treatment approaches are being explored. Investigators are evaluating the efficacy of various T2DM medications for possible use in AD, including but not limited to glucagon-like peptide-1 receptor agonists, and peroxisome proliferator-activated receptor-gamma agonists. Furthermore, there are 136 active trials involving 121 therapeutic agents targeting novel AD biomarkers. With these efforts, we are one step closer to alleviating the ravaging impact of AD on our communities.

scholarly journals TM4SF5 Knockout Protects Mice from Diet-Induced Obesity Partly by Regulating Autophagy in Adipose Tissue

2021 ◽  
Author(s):  
Cheoljun Choi ◽  
Yeonho Son ◽  
Jinyoung Kim ◽  
Yoon Keun Cho ◽  
Abhirup Saha ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Oxidative Metabolism ◽  
Metabolic Diseases ◽  
Mammalian Target Of Rapamycin ◽  
Regulatory Function ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Brown Adipose ◽  
Mtorc1 Signaling ◽  
Mitochondrial Oxidative Metabolism

Transmembrane 4 L six family member 5 (TM4SF5) functions as a sensor for lysosomal arginine levels and activates the mammalian target of rapamycin complex 1 (mTORC1). While the mTORC1 signaling pathway plays a key role in adipose tissue metabolism, the regulatory function of TM4SF5 in adipocytes remains unclear. This study aimed to establish a TM4SF5 knockout (KO) mouse model and investigated the effects of TM4SF5 KO on mTORC1 signaling-mediated autophagy and mitochondrial metabolism in adipose tissue. TM4SF5 expression was higher in inguinal white adipose tissue (iWAT) than in brown adipose tissue and significantly upregulated by a high-fat diet (HFD). TM4SF5 KO reduced mTORC1 activation and enhanced autophagy and lipolysis in adipocytes. RNA-seq analysis of TM4SF5 KO mouse iWAT showed that the expression of genes involved in peroxisome proliferator-activated receptor alpha signaling pathways and mitochondrial oxidative metabolism was upregulated. Consequently, TM4SF5 KO reduced adiposity and increased energy expenditure and mitochondrial oxidative metabolism. TM4SF5 KO prevented HFD-induced glucose intolerance and inflammation in adipose tissue. Collectively, our study demonstrated that TM4SF5 regulates autophagy and lipid catabolism in adipose tissue and suggested that TM4SF5 could be therapeutically targeted for the treatment of obesity-related metabolic diseases.

Sex hormones influence expression and function of peroxisome proliferator-activated receptor γ in adipocytes: pathophysiological aspects

2014 ◽  
Vol 20 (2) ◽  
Author(s):  
Hiromi Sato ◽  
Momoko Ishikawa ◽  
Hana Sugai ◽  
Asami Funaki ◽  
Yuki Kimura ◽  
...  
Keyword(s):  
Sex Hormones ◽  
Metabolic Diseases ◽  
Fat Distribution ◽  
Inflammatory Factors ◽  
Peroxisome Proliferator ◽  
Metabolic Homeostasis ◽  
Peroxisome Proliferator Activated Receptor ◽  
Pparγ Agonist ◽  
Post Menopausal ◽  
And Function

AbstractAdipose tissue plays important roles not only in storing fat but also in maintaining metabolic homeostasis by regulating hundreds of biological signaling events and the secretion of various cytokines. One of the central regulators of adipocyte differentiation is peroxisome proliferator-activated receptor γ (PPARγ), which promotes downstream transcriptional activities, such as adiponectin. Disruption of homeostasis leads to the onset of metabolic diseases such as type 2 diabetes and other triggers for metabolic syndrome. Males and post-menopausal females are more likely to be affected with metabolic diseases than pre-menopausal females, suggesting that sex hormones might be involved in the pathogenesis and development of metabolic diseases. Indeed, 17β-estradiol, testosterone, dihydrotestosterone, and their receptors clearly play a role in adipose regulation: they can alter fat distribution and can modify the expression and activities of PPARγ and its downstream adipocytokines. Furthermore, sex hormones affect inflammatory factors such as nitric oxygen, nitric oxygen synthase, and their surrounding components. Sex hormones are also suggested to be involved with sex differences in the efficacy of the PPARγ agonist thiazolidinediones. Therefore, thorough investigation of how sex hormone-dependent regulation of metabolic homeostasis occurs is necessary in order to develop individualized clinical therapies optimized with regard to each patient’s biological condition and drug sensitivities.

scholarly journals High Sugar Intake and Development of Skeletal Muscle Insulin Resistance and Inflammation in Mice: A Protective Role for PPAR-δAgonism

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Elisa Benetti ◽  
Raffaella Mastrocola ◽  
Mara Rogazzo ◽  
Fausto Chiazza ◽  
Manuela Aragno ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Signaling Pathways ◽  
Gastrocnemius Muscle ◽  
Metabolic Diseases ◽  
Whole Body ◽  
Intercellular Adhesion Molecule ◽  
Fibroblast Growth Factor 21 ◽  
Peroxisome Proliferator ◽  
Intercellular Adhesion Molecule 1 ◽  
Peroxisome Proliferator Activated Receptor

Peroxisome Proliferator Activated Receptor (PPAR)-δagonists may serve for treating metabolic diseases. However, the effects of PPAR-δagonism within the skeletal muscle, which plays a key role in whole-body glucose metabolism, remain unclear. This study aimed to investigate the signaling pathways activated in the gastrocnemius muscle by chronic administration of the selective PPAR-δagonist, GW0742 (1 mg/kg/day for 16 weeks), in male C57Bl6/J mice treated for 30 weeks with high-fructose corn syrup (HFCS), the major sweetener in foods and soft-drinks (15% wt/vol in drinking water). Mice fed with the HFCS diet exhibited hyperlipidemia, hyperinsulinemia, hyperleptinemia, and hypoadiponectinemia. In the gastrocnemius muscle, HFCS impaired insulin and AMP-activated protein kinase signaling pathways and reduced GLUT-4 and GLUT-5 expression and membrane translocation. GW0742 administration induced PPAR-δupregulation and improvement in glucose and lipid metabolism. Diet-induced activation of nuclear factor-κB and expression of inducible-nitric-oxide-synthase and intercellular-adhesion-molecule-1 were attenuated by drug treatment. These effects were accompanied by reduction in the serum concentration of interleukin-6 and increase in muscular expression of fibroblast growth factor-21. Overall, here we show that PPAR-δactivation protects the skeletal muscle against the metabolic abnormalities caused by chronic HFCS exposure by affecting multiple levels of the insulin and inflammatory cascades.

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