Peroxisome proliferator receptor gamma and the control of glucose metabolism: Insights from knockout mice

2019 ◽  
pp. 115-127
Author(s):  
Marina O. Fernandez ◽  
Nicholas J.G. Webster
Keyword(s):  
Glucose Metabolism ◽  
Knockout Mice ◽  
Peroxisome Proliferator

scholarly journals Hypoxic Exposure Increases Energy Expenditure by Increasing Carbohydrate Oxidation in Mice

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Yeram Park ◽  
Deunsol Hwang ◽  
Hun-Young Park ◽  
Jisu Kim ◽  
Kiwon Lim
Keyword(s):  
Glucose Metabolism ◽  
Energy Expenditure ◽  
Pyruvate Dehydrogenase ◽  
Hypoxic Condition ◽  
Open Circuit ◽  
Pyruvate Dehydrogenase Kinase ◽  
Hypoxic Exposure ◽  
Control Group ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor

Aims. Hypoxic exposure improves glucose metabolism. We investigated to validate the hypothesis that carbohydrate (CHO) oxidation could increase in mice exposed to severe hypoxic conditions. Methods. Seven-week-old male ICR mice (n=16) were randomly divided into two groups: the control group (CON) was kept in normoxic condition (fraction of inspired O2=21%) and the hypoxia group (HYP) was exposed to hypoxic condition (fraction of inspired O2=12%, ≈altitude of 4,300 m). The CON group was pair-fed with the HYP group. After 3 weeks of hypoxic exposure, we measured respiratory metabolism (energy expenditure and substrate utilization) at normoxic conditions for 24 hours using an open-circuit calorimetry system. In addition, we investigated changes in carbohydrate mechanism-related protein expression, including hexokinase 2 (HK2), pyruvate dehydrogenase (PDH), pyruvate dehydrogenase kinase 4 (PDK4), and regulator of the genes involved in energy metabolism (peroxisome proliferator-activated receptor gamma coactivator 1-alpha, PGC1α) in soleus muscle. Results. Energy expenditure (EE) and CHO oxidation over 24 hours were higher in the HYP group by approximately 15% and 34% (p<0.001), respectively. Fat oxidation was approximately 29% lower in the HYP group than the CON group (p<0.01). Body weight gains were significantly lower in the HYP group than in the CON group (CON vs. HYP; 1.9±0.9 vs. −0.3±0.9; p<0.001). Hypoxic exposure for 3 weeks significantly reduced body fat by approximately 42% (p<0.001). PDH and PGC1α protein levels were significantly higher in the HYP group (p<0.05). Additionally, HK2 was approximately 21% higher in the HYP group. Conclusions. Hypoxic exposure might significantly enhance CHO oxidation by increasing the expression of PDH and HK2. This investigation can be useful for patients with impaired glucose metabolism, such as those with type 2 diabetes.

scholarly journals Regional registration of [6-14 C]glucose metabolism during brain activation of α-syntrophin knockout mice

2013 ◽  
Vol 125 (2) ◽  
pp. 247-259 ◽  
Author(s):  
Nancy F. Cruz ◽  
Kelly K. Ball ◽  
Stanley C. Froehner ◽  
Marvin E. Adams ◽  
Gerald A. Dienel
Keyword(s):  
Glucose Metabolism ◽  
Knockout Mice ◽  
Brain Activation ◽  
Regional Registration

scholarly journals The depot-specific and essential roles of CBP/p300 in regulating adipose plasticity

2019 ◽  
Vol 240 (2) ◽  
pp. 257-269 ◽  
Author(s):  
Maria Namwanje ◽  
Longhua Liu ◽  
Michelle Chan ◽  
Nikki Aaron ◽  
Michael J Kraakman ◽  
...  
Keyword(s):  
Body Weight ◽  
Glucose Metabolism ◽  
Glucose Tolerance ◽  
Knockout Mice ◽  
Metabolic Disorders ◽  
Physiological Effects ◽  
Double Knockout ◽  
Adipose Tissues ◽  
Diet Induced Obesity ◽  
Specific Deletion

Fat remodeling has been extensively explored through protein deacetylation, but not yet acetylation, as a viable therapeutic approach in the management of obesity and related metabolic disorders. Here, we investigated the functions of key acetyltransferases CBP/p300 in adipose remodeling and their physiological effects by generating adipose-specific deletion of CBP (Cbp-AKO), p300 (p300-AKO) and double-knockout (Cbp/p300-AKO) models. We demonstrated that Cbp-AKO exhibited marked brown remodeling of inguinal WAT (iWAT) but not epididymal WAT (eWAT) after cold exposure and that this pattern was exaggerated in diet-induced obesity (DIO). Despite this striking browning phenotype, loss of Cbp was insufficient to impact body weight or glucose tolerance. In contrast, ablation of p300 in adipose tissues had minimal effects on fat remodeling and adiposity. Surprisingly, double-knockout mice (Cbp/p300-AKO) developed severe lipodystrophy along with marked hepatic steatosis, hyperglycemia and hyperlipidemia. Furthermore, we demonstrated that pharmacological inhibition of Cbp and p300 activity suppressed adipogenesis. Collectively, these data suggest that (i) CBP, but not p300, has distinct functions in regulating fat remodeling and that this occurs in a depot-selective manner; (ii) brown remodeling occurs independently of the improvements in glucose metabolism and obesity and (iii) the combined roles of CBP and p300 are indispensable for normal adipose development.

GLP-1-mediated delivery of the PPAR𝛼/𝛾 dual-agonist Tesaglitazar improves obesity and glucose metabolism in mice

2021 ◽  
Author(s):  
Carmelo Quarta ◽  
Kerstin Stemmer ◽  
Aaron Novikoff ◽  
Bin Yang ◽  
Felix Klingelhuber ◽  
...  
Keyword(s):  
Body Weight ◽  
Glucose Metabolism ◽  
Peroxisome Proliferator ◽  
Protein Targets ◽  
Beneficial Effects ◽  
Glucose And Lipid Metabolism ◽  
Therapeutic Value ◽  
Affect Body Weight ◽  
Peroxisome Proliferator Activated Receptors ◽  
Dual Agonist

Abstract Dual-agonists activating the peroxisome proliferator-activated receptors alpha and gamma (PPAR𝛼/𝛾) have shown beneficial effects on glucose and lipid metabolism in patients with type 2 diabetes, but their development was discontinued due to unfavorable cardiovascular and/or renal effects. Here we report the design and preclinical evaluation of a molecule that covalently links the PPAR𝛼/𝛾 dual-agonist Tesaglitazar to GLP-1 to allow for the GLP-1 receptor-dependent delivery of Tesaglitazar. GLP-1/Tesaglitazar does not differ from matched GLP-1 in GLP-1R signaling, but shows GLP-1R-dependent PPAR𝛾-RXR heterodimerization with enhanced efficacy to improve body weight, food intake, and glucose metabolism relative to GLP-1 or Tesaglitazar in mice with diet- and genetically-induced obesity. The conjugate fails to affect body weight and glucose metabolism in GLP-1R knockout (ko) mice and shows preserved effects in DIO mice at doses subthreshold for GLP-1 and Tesaglitazar to improve metabolism. Consistent with the GLP-1R expression pattern, LC/MS-based proteomics identified a series of novel PPAR protein targets in the hypothalamus that are acutely upregulated by Tesaglitazar and by GLP-1/Tesaglitazar, but not by treatment with GLP-1. Collectively, our data show that GLP-1/Tesaglitazar improves energy and glucose metabolism with superior efficacy to GLP-1 or Tesaglitazar alone and suggest that this conjugate holds therapeutic value to treat hyperglycemia and insulin resistance.

scholarly journals PPAR-δin Vascular Pathophysiology

PPAR Research ◽  
2008 ◽  
Vol 2008 ◽  
pp. 1-10 ◽  
Author(s):  
Nanping Wang
Keyword(s):  
Transcription Factors ◽  
Cell Growth ◽  
Glucose Metabolism ◽  
Nuclear Receptor ◽  
Therapeutic Intervention ◽  
Peroxisome Proliferator ◽  
Cardiovascular Disorders ◽  
Direct Effects ◽  
Cell Growth And Differentiation ◽  
Peroxisome Proliferator Activated Receptors

Peroxisome proliferator-activated receptors belong to the superfamily of ligand-dependent nuclear receptor transcription factors, which include three subtypes: PPAR-α,β/δ, andγ. PPAR-δ, play important roles in the regulation of cell growth and differentiation as well as tissue wound and repair. Emerging evidence has also demonstrated that PPAR-δis implicated in lipids and glucose metabolism. Most recently, the direct effects of PPAR-δon cardiovascular processes such as endothelial function and angiogenesis have also been investigated. Therefore, it is suggested that PPAR-δmay have critical roles in cardiovascular pathophysiology and is a potential target for therapeutic intervention of cardiovascular disorders such as atherosclerosis.

PPARγ preservation via promoter demethylation alleviates osteoarthritis in mice

2019 ◽  
Vol 78 (10) ◽  
pp. 1420-1429 ◽  
Author(s):  
Xiaobo Zhu ◽  
Fang Chen ◽  
Ke Lu ◽  
Ai Wei ◽  
Qing Jiang ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Knockout Mice ◽  
Cartilage Damage ◽  
Critical Role ◽  
Methylation Status ◽  
Promoter Hypermethylation ◽  
Dna Methyltransferases ◽  
Degenerative Joint Disease ◽  
Joint Disease ◽  
Peroxisome Proliferator

ObjectivesOsteoarthritis (OA) is the most common degenerative joint disease in aged population and its development is significantly influenced by aberrant epigenetic modifications of numerous OA susceptible genes; however, the precise mechanisms that DNA methylation alterations affect OA pathogenesis remain undefined. This study investigates the critical role of epigenetic PPARγ (peroxisome proliferator–activated receptor-gamma) suppression in OA development.MethodsArticular cartilage expressions of PPARγ and bioactive DNA methyltransferases (DNMTs) from OA patients and mice incurred by DMM (destabilisation of medial meniscus) were examined. DNA methylation status of both human and mouse PPARγ promoters were assessed by methylated specific PCR and/or bisulfite-sequencing PCR. OA protections by a pharmacological DNA demethylating agent 5Aza (5-Aza-2'-deoxycytidine) were compared between wild type and PPARγ knockout mice.ResultsArticular cartilages from both OA patients and DMM mice display substantial PPARγ suppressions likely due to aberrant elevations of DNMT1 and DNMT3a and consequential PPARγ promoter hypermethylation. 5Aza known to inhibit both DNMT1 and DNMT3a reversed the PPARγ promoter hypermethylation, recovered the PPARγ loss and effectively attenuated the cartilage damage in OA mice. 5Aza also inhibited the OA-associated excessive inflammatory cytokines and deficit anti-oxidant enzymes, which were blocked by a specific PPARγ inhibitor in cultured chondrocytes. Further, 5Aza-confered protections against the cartilage damage and the associated abnormalities of OA-susceptible factors were significantly abrogated in PPARγ knockout mice.ConclusionEpigenetic PPARγ suppression plays a key role in OA development and PPARγ preservation via promoter demethylation possesses promising therapeutic potentials in clinical treatment of OA and the related joint diseases.

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