scholarly journals Increased Energy Expenditure and Protection from Diet-Induced Obesity in Mice Lacking the cGMP-Specific Phosphodiesterase PDE9

2021 ◽  
Author(s):  
Ryan P. Ceddia ◽  
Dianxin Liu ◽  
Fubiao Shi ◽  
Mark K. Crowder ◽  
Sumita Mishra ◽  
...  

Cyclic nucleotides, cAMP and cGMP, are important second messengers for the regulation of adaptive thermogenesis. Their levels are controlled not only by their synthesis but also their degradation. Since pharmacological inhibitors of cGMP-specific phosphodiesterase 9 (PDE9) can increase PKG signaling and UCP1 expression in adipocytes, we sought to elucidate the role of PDE9 on energy balance and glucose homeostasis <i>in vivo</i>. Mice with targeted disruption of the PDE9 gene, <i>Pde9a</i>, were fed nutrient matched high-fat (HFD) or low-fat diets (LFD). <i>Pde9a</i><sup>‑/‑</sup> mice were resistant to HFD induced obesity, exhibiting a global increase in energy expenditure, while brown adipose tissue (AT) had increased respiratory capacity and elevated expression of <i>Ucp1 </i>and other thermogenic genes. Reduced adiposity of HFD-fed <i>Pde9a</i><sup>‑/‑</sup> mice was associated with improvements in glucose handling and hepatic steatosis. Cold exposure or treatment with β-adrenergic receptor agonists markedly decreased <i>Pde9a</i> expression in brown AT and cultured brown adipocytes, while <i>Pde9a<sup>‑/‑</sup></i> mice exhibited a greater increase in AT browning; together suggesting that the PDE9-cGMP pathway augments classical cold-induced β-adrenergic/cAMP AT browning and energy expenditure. These findings suggest PDE9 is a previously unrecognized regulator of energy metabolism and that its inhibition may be a valuable avenue to explore for combating metabolic disease.

2021 ◽  
Author(s):  
Ryan P. Ceddia ◽  
Dianxin Liu ◽  
Fubiao Shi ◽  
Mark K. Crowder ◽  
Sumita Mishra ◽  
...  

Cyclic nucleotides, cAMP and cGMP, are important second messengers for the regulation of adaptive thermogenesis. Their levels are controlled not only by their synthesis but also their degradation. Since pharmacological inhibitors of cGMP-specific phosphodiesterase 9 (PDE9) can increase PKG signaling and UCP1 expression in adipocytes, we sought to elucidate the role of PDE9 on energy balance and glucose homeostasis <i>in vivo</i>. Mice with targeted disruption of the PDE9 gene, <i>Pde9a</i>, were fed nutrient matched high-fat (HFD) or low-fat diets (LFD). <i>Pde9a</i><sup>‑/‑</sup> mice were resistant to HFD induced obesity, exhibiting a global increase in energy expenditure, while brown adipose tissue (AT) had increased respiratory capacity and elevated expression of <i>Ucp1 </i>and other thermogenic genes. Reduced adiposity of HFD-fed <i>Pde9a</i><sup>‑/‑</sup> mice was associated with improvements in glucose handling and hepatic steatosis. Cold exposure or treatment with β-adrenergic receptor agonists markedly decreased <i>Pde9a</i> expression in brown AT and cultured brown adipocytes, while <i>Pde9a<sup>‑/‑</sup></i> mice exhibited a greater increase in AT browning; together suggesting that the PDE9-cGMP pathway augments classical cold-induced β-adrenergic/cAMP AT browning and energy expenditure. These findings suggest PDE9 is a previously unrecognized regulator of energy metabolism and that its inhibition may be a valuable avenue to explore for combating metabolic disease.


2021 ◽  
Author(s):  
Ryan P. Ceddia ◽  
Dianxin Liu ◽  
Fubiao Shi ◽  
Sumita Mishra ◽  
David A. Kass ◽  
...  

AbstractObesity is a central component to cardiometabolic diseases, predisposing patients to both heart failure and diabetes. As therapeutics targeting caloric intake have limited long-term efficacy, greater interest has been on increasing thermogenic energy expenditure. Cyclic nucleotides, cAMP and cGMP, are important second messengers that are critical for the regulation of adaptive thermogenesis. These are regulated not only by their synthesis but also by their degradation. Pharmacological inhibitors of the cGMP-specific phosphodiesterase 9 (PDE9) increased PKG signaling and UCP1 expression in adipocytes. To elucidate the role of PDE9 on energy balance and glucose homeostasis in vivo, mice carrying a targeted disruption of the PDE9 gene, Pde9a, were fed a nutrient matched high-fat diet (HFD) or low-fat diet (LFD). Pde9a-/- mice were resistant to obesity induced by a HFD. Pde9a-/- mice exhibited a global increase in energy expenditure while the brown adipose tissue had elevated expression of Ucp1 and other thermogenic genes. The reduced adiposity of HFD-fed Pde9a-/- mice was associated with improvements in glucose handling and hepatic steatosis. These findings support the conclusion that PDE9 is a critical regulator of energy metabolism and suggest that inhibiting this enzyme may be an important avenue to explore for combating metabolic disease.


2021 ◽  
Author(s):  
Xue Han ◽  
Jielong Guo ◽  
Yunxiao Gao ◽  
Weidong Huang ◽  
Jicheng Zhan ◽  
...  

Since obesity occurs when energy intake is higher than energy expenditure, increasing energy expenditure is an effective strategy to prevent or treat obesity. Brown adipose tissue (BAT) is a classic...


2016 ◽  
Vol 310 (5) ◽  
pp. E346-E354 ◽  
Author(s):  
Marika Zietak ◽  
Leslie P. Kozak

It has been proposed that diet-induced obesity at thermoneutrality (TN; 29°C) is reduced by a UCP1-dependent thermogenesis; however, it has not been shown how UCP1-dependent thermogenesis can be activated in the absence of sympathetic activity. A recent study provides such a mechanism by showing that dietary bile acids (BAs) suppress obesity in mice fed a high-fat diet (HFD) by a mechanism dependent on type 2 deiodinase (DIO2); however, neither a role for UCP1 nor the influence of sympathetic activity was properly assessed. To test whether the effects of BAs on adiposity are independent of Ucp1 and cold-activated thermogenesis, obesity phenotypes were determined in C57BL6/J.+/+ (WT) and C57BL6/J. Ucp1.−/− mice ( Ucp1-KO) housed at TN and fed a HFD with or without 0.5% (wt/wt) cholic acid (CA) for 9 wk. CA in a HFD reduced adiposity and hepatic lipogenesis and improved glucose tolerance in WT but not in Ucp1-KO mice and was accompanied by increases in food intake and energy expenditure (EE). In iBAT, CA increased Ucp1 mRNA and protein levels 1.5- and twofold, respectively, and increased DIO2 and TGR5 protein levels in WT mice. Despite enhanced Dio2 expression in Ucp1-KO and Ucp1-KO-CA treated mice, this did not enhance the ability of BAs to reduce obesity. By comparing the effects of BAs on WT and Ucp1-KO mice at TN, our study showed that BAs suppress diet-induced obesity by increasing EE through a mechanism dependent on Ucp1 expression, which is likely independent of adrenergic signaling.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Enrique Calvo ◽  
Noelia Keiran ◽  
Catalina Núñez-Roa ◽  
Elsa Maymó-Masip ◽  
Miriam Ejarque ◽  
...  

AbstractAdipose-derived mesenchymal stem cells (ASCs) are a promising option for the treatment of obesity and its metabolic co-morbidities. Despite the recent identification of brown adipose tissue (BAT) as a potential target in the management of obesity, the use of ASCs isolated from BAT as a therapy for patients with obesity has not yet been explored. Metabolic activation of BAT has been shown to have not only thermogenic effects, but it also triggers the secretion of factors that confer protection against obesity. Herein, we isolated and characterized ASCs from the visceral adipose tissue surrounding a pheochromocytoma (IB-hASCs), a model of inducible BAT in humans. We then compared the anti-obesity properties of IB-hASCs and human ASCs isolated from visceral white adipose tissue (W-hASCs) in a murine model of diet-induced obesity. We found that both ASC therapies mitigated the metabolic abnormalities of obesity to a similar extent, including reducing weight gain and improving glucose tolerance. However, infusion of IB-hASCs was superior to W-hASCs in suppressing lipogenic and inflammatory markers, as well as preserving insulin secretion. Our findings provide evidence for the metabolic benefits of visceral ASC infusion and support further studies on IB-hASCs as a therapeutic option for obesity-related comorbidities.


2021 ◽  
Author(s):  
Sebastian Dieckmann ◽  
Akim Strohmeyer ◽  
Monja Willershaeuser ◽  
Stefanie Maurer ◽  
Wolfgang Wurst ◽  
...  

Objective Activation of uncoupling protein 1 (UCP1) in brown adipose tissue (BAT) upon cold stimulation leads to substantial increase in energy expenditure to defend body temperature. Increases in energy expenditure after a high caloric food intake, termed diet-induced thermogenesis, are also attributed to BAT. These properties render BAT a potential target to combat diet-induced obesity. However, studies investigating the role of UCP1 to protect against diet-induced obesity are controversial and rely on the phenotyping of a single constitutive UCP1-knockout model. To address this issue, we generated a novel UCP1-knockout model by Cre-mediated deletion of Exon 2 in the UCP1 gene. We studied the effect of constitutive UCP1 knockout on metabolism and the development of diet-induced obesity. Methods UCP1 knockout and wildtype mice were housed at 30°C and fed a control diet for 4-weeks followed by 8-weeks of high-fat diet. Body weight and food intake were monitored continuously over the course of the study and indirect calorimetry was used to determine energy expenditure during both feeding periods. Results Based on Western blot analysis, thermal imaging and noradrenaline test, we confirmed the lack of functional UCP1 in knockout mice. However, body weight gain, food intake and energy expenditure were not affected by deletion of UCP1 gene function during both feeding periods. Conclusion Conclusively, we show that UCP1 does not protect against diet-induced obesity at thermoneutrality. Further we introduce a novel UCP1-KO mouse enabling the generation of conditional UCP1-knockout mice to scrutinize the contribution of UCP1 to energy metabolism in different cell types or life stages.


2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A45-A46
Author(s):  
Evangelia Evelyn Tsakiridis ◽  
Marisa Morrow ◽  
Andrea Llanos ◽  
Bo Wang ◽  
Alison Holloway ◽  
...  

Abstract Deltamethrin is a commonly used pesticide for the control of mosquito populations. Despite widespread use, the effects of deltamethrin on adiposity and glucose homeostasis have been equivocal with some studies showing increased, decreased and no effect on adiposity and glycemic control. However, no study to date has investigated the effect of deltamethrin in mice housed at thermoneutral temperatures, which is important for modelling metabolic diseases in rodents due to reduced thermal stress and constitutive activation of brown adipose tissue. In the current study we demonstrate for the first time that deltamethrin reduces uncoupling protein-1 expression in brown adipocytes cultured in vitro at concentrations as low as 1pm. Meanwhile, in-vivo deltamethrin does not appear to alter glycemic control or promote adiposity at exposures equivalent to 0.01, 0.1 or 1.0 mg/kg/day. Together, our study demonstrates environmentally relevant exposure to deltamethrin does not exacerbate diet induced obesity or insulin resistance.


Open Biology ◽  
2016 ◽  
Vol 6 (8) ◽  
pp. 160131 ◽  
Author(s):  
Yuzhong Xiao ◽  
Tingting Xia ◽  
Junjie Yu ◽  
Yalan Deng ◽  
Hao Liu ◽  
...  

Although numerous functions of inositol-requiring enzyme 1α (IRE1α) have been identified, a role of IRE1α in pro-opiomelanocortin (POMC) neurons in the arcuate nucleus of the hypothalamus is largely unknown. Here, we showed that mice lacking IRE1α specifically in POMC neurons (PIKO) are lean and resistant to high-fat diet-induced obesity and obesity-related insulin resistance, liver steatosis and leptin resistance. Furthermore, PIKO mice had higher energy expenditure, probably due to increased thermogenesis in brown adipose tissue. Additionally, α-melanocyte-stimulating hormone production was increased in the hypothalamus of PIKO mice. These results demonstrate that IRE1α in POMC neurons plays a critical role in the regulation of obesity and obesity-related metabolic disorders. Our results also suggest that IRE1α is not only an endoplasmic reticulum stress sensor, but also a new potential therapeutic target for obesity and obesity-related metabolic diseases.


2018 ◽  
Vol 115 (30) ◽  
pp. 7819-7824 ◽  
Author(s):  
Yuliya Skorobogatko ◽  
Morgan Dragan ◽  
Claudia Cordon ◽  
Shannon M. Reilly ◽  
Chao-Wei Hung ◽  
...  

Insulin increases glucose uptake into adipose tissue and muscle by increasing trafficking of the glucose transporter Glut4. In cultured adipocytes, the exocytosis of Glut4 relies on activation of the small G protein RalA by insulin, via inhibition of its GTPase activating complex RalGAP. Here, we evaluate the role of RalA in glucose uptake in vivo with specific chemical inhibitors and by generation of mice with adipocyte-specific knockout of RalGAPB. RalA was profoundly activated in brown adipose tissue after feeding, and its inhibition prevented Glut4 exocytosis. RalGAPB knockout mice with diet-induced obesity were protected from the development of metabolic disease due to increased glucose uptake into brown fat. Thus, RalA plays a crucial role in glucose transport in adipose tissue in vivo.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Haruka Kimura ◽  
Tomohisa Nagoshi ◽  
Yuhei Oi ◽  
Akira Yoshii ◽  
Yoshiro Tanaka ◽  
...  

AbstractIncreasing evidence suggests natriuretic peptides (NPs) coordinate inter-organ metabolic crosstalk with adipose tissues and play a critical role in energy metabolism. We recently reported A-type NP (ANP) raises intracellular temperature in cultured adipocytes in a low-temperature-sensitive manner. We herein investigated whether exogenous ANP-treatment exerts a significant impact on adipose tissues in vivo. Mice fed a high-fat-diet (HFD) or normal-fat-diet (NFD) for 13 weeks were treated with or without ANP infusion subcutaneously for another 3 weeks. ANP-treatment significantly ameliorated HFD-induced insulin resistance. HFD increased brown adipose tissue (BAT) cell size with the accumulation of lipid droplets (whitening), which was suppressed by ANP-treatment (re-browning). Furthermore, HFD induced enlarged lipid droplets in inguinal white adipose tissue (iWAT), crown-like structures in epididymal WAT, and hepatic steatosis, all of which were substantially attenuated by ANP-treatment. Likewise, ANP-treatment markedly increased UCP1 expression, a specific marker of BAT, in iWAT (browning). ANP also further increased UCP1 expression in BAT with NFD. Accordingly, cold tolerance test demonstrated ANP-treated mice were tolerant to cold exposure. In summary, exogenous ANP administration ameliorates HFD-induced insulin resistance by attenuating hepatic steatosis and by inducing adipose tissue browning (activation of the adipose tissue thermogenic program), leading to in vivo thermogenesis during cold exposure.


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