Abstract P430: VSMCs Increase Glutamine Utilization For Energy Metabolism During Obesity

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Krystal M Roggerson ◽  
Sharon Francis

Obesity increases the risk of developing cardiovascular disease through vascular remodeling though the underlying mechanisms are not entirely understood. However, metabolic fuel partitioning and mitochondrial flexibility during energy metabolism may play a critical role. We demonstrated serum and glucocorticoid-inducible kinase 1 (SGK-1) is up-regulated in the vasculature of diet-induced obese mice and that SGK-1 deletion is protective against obesity-induced vascular remodeling by metabolically reprogramming vascular smooth muscle cell (VSMC) energy metabolism towards oxidative phosphorylation (OXPHOS) and away from glycolysis. Mitochondrial substrate availability and utilization of the primary metabolic fuels glucose, long chain fatty acids (LCFAs) and glutamine can drive metabolic reprogramming. Therefore, alterations in fuel utilization may contribute to vascular remodeling during obesity. The purpose of this study was to examine SGK-1’s role in 1) fuel dependency: a cell’s reliance for a specific fuel and 2) fuel capacity: a cell’s ability to oxidize a specific fuel to meet cellular energy demand under low-fat and high-fat diet-induced obesity. Using the MitoXpress Oxygen Consumption assay which measures OXPHOS, primary VSMCs isolated from wildtype (WT) and SMC-specific SGK-1 knockout (smSGK-1 KO) mice fed a 10% kcal low-fat or 45% kcal high-fat diet for eight weeks were seeded in a 96-well plate at a density of 6x10 4 cells/well in culture medium. To assess fuel dependency, cells were treated with fuel pathway inhibitors UK5099, Etomoxir or BPTES to block glucose, LCFA or glutamine oxidation, respectively. To measure fuel capacity, VSMCs were treated with a combination of two pathway inhibitors simultaneously. Next, samples were overlaid with a fluorescent extracellular oxygen consumption reagent, sealed with high-sensitivity mineral oil, then signals were read at 1.5-minute intervals for 2 hours at Ex/Em= 380/650 nm. Our results show WT VSMCs are exclusively glucose-dependent for OXPHOS regardless of dietary conditions. However, SGK-1 deletion induces a dependency for all three fuels for OXPHOS in VSMCs under low- and high-fat conditions. Even though WT and smSGK-1 KO VSMCs preferentially oxidized glucose for OXPHOS under low-fat conditions; SGK-1 deletion resulted in a 2.2-fold increase in glutamine capacity. Alternatively, WT VSMCs exposed to obesogenic conditions preferentially oxidized glutamine whereas SGK-1 deletion induced a nearly equal partitioning of all three fuels during obesity suggesting elevated mitochondrial flexibility. Overall, this study suggests SGK-1 increases glucose dependency for energy metabolism under physiological and obesogenic conditions. Also, increased glutamine utilization for OXPHOS during obesity may be an underlying cause of VSMC dysfunction and subsequent vascular impairment.

2011 ◽  
Vol 57 (1) ◽  
pp. 103-113 ◽  
Author(s):  
Wendy Keung ◽  
Virgilio J J Cadete ◽  
Arivazhagan Palaniyappan ◽  
Amissa Jablonski ◽  
Melanie Fischer ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Laura K. Cole ◽  
Genevieve C. Sparagna ◽  
Marilyne Vandel ◽  
Bo Xiang ◽  
Vernon W. Dolinsky ◽  
...  

AbstractBerberine (BBR) is an isoquinoline alkaloid from plants known to improve cardiac mitochondrial function in gestational diabetes mellitus (GDM) offspring but the mechanism is poorly understood. We examined the role of the mitochondrial phospholipid cardiolipin (CL) in mediating this cardiac improvement. C57BL/6 female mice were fed either a Lean-inducing low-fat diet or a GDM-inducing high-fat diet for 6 weeks prior to breeding. Lean and GDM-exposed male offspring were randomly assigned a low-fat, high-fat, or high-fat diet containing BBR at weaning for 12 weeks. The content of CL was elevated in the heart of GDM offspring fed a high fat diet containing BBR. The increase in total cardiac CL was due to significant increases in the most abundant and functionally important CL species, tetralinoleoyl-CL and this correlated with an increase in the expression of the CL remodeling enzyme tafazzin. Additionally, BBR treatment increased expression of cardiac enzymes involved in fatty acid uptake and oxidation and electron transport chain subunits in high fat diet fed GDM offspring. Thus, dietary BBR protection from cardiac dysfunction in GDM exposed offspring involves improvement in mitochondrial function mediated through increased synthesis of CL.


2021 ◽  
Vol 22 (10) ◽  
pp. 5390
Author(s):  
Qianhui Zeng ◽  
Nannan Wang ◽  
Yaru Zhang ◽  
Yuxuan Yang ◽  
Shuangshuang Li ◽  
...  

Obesity-induced adipose tissue dysfunction and disorders of glycolipid metabolism have become a worldwide research priority. Zfp217 plays a crucial role in adipogenesis of 3T3-L1 preadipocytes, but about its functions in animal models are not yet clear. To explore the role of Zfp217 in high-fat diet (HFD)-induced obese mice, global Zfp217 heterozygous knockout (Zfp217+/−) mice were constructed. Zfp217+/− mice and Zfp217+/+ mice fed a normal chow diet (NC) did not differ significantly in weight gain, percent body fat mass, glucose tolerance, or insulin sensitivity. When challenged with HFD, Zfp217+/− mice had less weight gain than Zfp217+/+ mice. Histological observations revealed that Zfp217+/− mice fed a high-fat diet had much smaller white adipocytes in inguinal white adipose tissue (iWAT). Zfp217+/− mice had improved metabolic profiles, including improved glucose tolerance, enhanced insulin sensitivity, and increased energy expenditure compared to the Zfp217+/+ mice under HFD. We found that adipogenesis-related genes were increased and metabolic thermogenesis-related genes were decreased in the iWAT of HFD-fed Zfp217+/+ mice compared to Zfp217+/− mice. In addition, adipogenesis was markedly reduced in mouse embryonic fibroblasts (MEFs) from Zfp217-deleted mice. Together, these data indicate that Zfp217 is a regulator of energy metabolism and it is likely to provide novel insight into treatment for obesity.


2020 ◽  
Vol 26 (Supplement_1) ◽  
pp. S8-S9
Author(s):  
Julia Fritsch ◽  
Alejandra Quintero ◽  
Judith Pignac-Kobinger ◽  
Luis Garces ◽  
Ana Santander ◽  
...  

Abstract Background and Aims There is a lack of evidence-based dietary interventions in ulcerative colitis (UC) management. A diet high in fat and animal meat has been linked to an increased risk of UC. The aim of our study was to use a multilayered, multi-omic approach to comprehensively characterize the effect of a low fat, high fiber diet or a high fat diet in UC patients. Methods We enrolled patients with UC who were in remission or had mild disease with a flare within the last 18 months. We used a cross-over design in which patients received two dietary interventions: a low fat diet (LFD), containing 10% total calories from fat with an omega 6 to 3 ratio of below 3:1, and an idealized standard American diet (SAD), containing 35–40% total calories from fat with an omega 6 to 3 ratio of 20–30:1. Each diet was four weeks long with a two-week wash-out in between. The diet was catered and delivered to patients’ homes. Clinical symptoms, quality of life, and biochemical data were collected. Stool was collected for microbiome and metabolomic analyses. The primary endpoint was to determine adherence to a specified diet using catered meals; the secondary endpoint was to determine the clinical and subclinical effects of a low fat, high fiber diet or high fat diet in UC. Results Baseline diets varied widely but were generally lower in fiber as well as fruits and vegetables and higher in saturated fat than either of the study diets. There was a high rate of adherence to catered meals (SAD=86.68%, LFD=84.8%) with a 96.8% and 94.33% adherence to fat for SAD and LFD respectively. Patients that started in remission remained in remission (partial Mayo and sIBDQ). Following a LFD, patients saw a 20% improvement in their quality of life as measured by sIBDQ compared to their baseline. The effect of diet intervention on microbial diversity was reflected in the beta diversity with a significant increase in Faecalibacterium prausnitzii after LFD. CRP, sIBDQ, IL-6, and IL1β had a significant effect on overall gut microbiota composition as measured by Bray Curtis beta diversity (PERMANOVA)(P<0.007, P<0.001, P<0.021, P<0.048 respectively). The top taxa that contributes the most to this microbial variation from these clinical parameters was Faecalibacterium prausnitzii. Patients following a SAD had an increase in lauric acid, myristic acid, and N-oleoyl-L-phenylalanine with an increase in omega-6 metabolism pathways. Patients following a LFD had higher glycine, alanine, and phenyllactic acid with omega 3 metabolism pathways increased after LFD. Conclusions A low fat, high fiber diet is well tolerated and did not increase biochemical markers of inflammation. Catered meals and collection of microbiome, metabolome and biochemical data may allow early stratification of diet responders.


2011 ◽  
Vol 435 (2) ◽  
pp. 519-528 ◽  
Author(s):  
Brian E. Sansbury ◽  
Daniel W. Riggs ◽  
Robert E. Brainard ◽  
Joshua K. Salabei ◽  
Steven P. Jones ◽  
...  

During cardiac remodelling, the heart generates higher levels of reactive species; yet an intermediate ‘compensatory’ stage of hypertrophy is associated with a greater ability to withstand oxidative stress. The mechanisms underlying this protected myocardial phenotype are poorly understood. We examined how a cellular model of hypertrophy deals with electrophilic insults, such as would occur upon ischaemia or in the failing heart. For this, we measured energetics in control and PE (phenylephrine)-treated NRCMs (neonatal rat cardiomyocytes) under basal conditions and when stressed with HNE (4-hydroxynonenal). PE treatment caused hypertrophy as indicated by augmented atrial natriuretic peptide and increased cellular protein content. Hypertrophied myocytes demonstrated a 2.5-fold increase in ATP-linked oxygen consumption and a robust augmentation of oligomycin-stimulated glycolytic flux and lactate production. Hypertrophied myocytes displayed a protected phenotype that was resistant to HNE-induced cell death and a unique bioenergetic response characterized by a delayed and abrogated rate of oxygen consumption and a 2-fold increase in glycolysis upon HNE exposure. This augmentation of glycolytic flux was not due to increased glucose uptake, suggesting that electrophile stress results in utilization of intracellular glycogen stores to support the increased energy demand. Hypertrophied myocytes also had an increased propensity to oxidize HNE to 4-hydroxynonenoic acid and sustained less protein damage due to acute HNE insults. Inhibition of aldehyde dehydrogenase resulted in bioenergetic collapse when myocytes were challenged with HNE. The integration of electrophile metabolism with glycolytic and mitochondrial energy production appears to be important for maintaining myocyte homoeostasis under conditions of increased oxidative stress.


2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Stefania Simeone ◽  
Talin Ebrahimian ◽  
Veronique Michaud ◽  
Stephanie Lehoux

Atherosclerotic plaques form in regions of low blood flow, whereas vessels exposed to high shear stress remain lesion-free. We hypothesized that exposing established atherosclerotic plaques to elevated shear stress leads to lesion regression by facilitating inflammatory cell movement within the plaque. We developed a model of arteriovenous fistula (AVF) in mice, where the right carotid artery is anastomosed into the jugular vein. LDLR-/- mice were placed on a high-fat diet. Control mice were sacrificed at week 12, which coincided with sham and AVF surgery. Sham and AVF mice were kept on a high-fat diet for a further 4 weeks. This procedure increases the shear stress in the brachiocephalic artery (BCA) and leads to a 51% plaque regression in AVF. All groups had comparable lipid levels. However, BCA plaque macrophage, smooth muscle cell and collagen content was halved in AVF. We observed greater gelatinase activity in plaques of AVF mice, suggesting a role for matrix metalloproteinases (MMPs) in plaque regression. MMP-9 and MMP-3 expression was increased in AVF plaques whereas MMP-2 and MMP-14 expression was decreased (p<0.05). A separate group of mice was therefore treated post-surgery with an MMP inhibitor, doxycycline, or with a TIMP-1 over-expressing plasmid. Both prevented the reduction in plaque size in the AVF group. To better define the mechanism of plaque regression in the AVF, we devised an endothelial cell (EC)-macrophage co-culture system where the ECs were exposed to high, low or no shear stress, and macrophages exposed to the EC effluent. There was a 2.5 fold increase in the migration of macrophages exposed to high shear effluent vs. low shear (p<0.05). This coincided with a 3-fold increase in the number of macrophages expressing activated β1 integrin in the high shear conditions. Uptake of apoptotic cells by macrophages was also 25% higher in the high shear vs. static (p<0.05). When repeated using the MMP inhibitor, GM6001, the high shear increase in migration was blocked in the presence of MMP inhibition; however, it had no effect on cell phagocytosis. Our findings suggest that shear stress acting on ECs may influence the cells within the plaque by increasing MMP activity allowing for better macrophage motility, an important feature of regressing plaques.


2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Megha Murali ◽  
Carla Taylor ◽  
Peter Zahradka ◽  
Jeffrey Wigle

Background and Objective: Arterial stiffness is recognized as being an independent predictor of incipient vascular disease associated with obesity and metabolic syndrome. In obese subjects, the decrease in the plasma level of adiponectin, an anti-diabetic and anti-atherogenic adipokine, is well known. Hence the aim of our study was to examine the effect of loss of adiponectin on the development of arterial stiffness in response to a high fat diet. Methods and Results: Male 8-week old adiponectin knockout (APN KO) and C57BL/6 (control) mice were fed a high fat diet (60% Calories from fat) for 12 weeks to induce obesity and insulin resistance (n=10/group). APN KO and C57BL/6 mice were fed a low fat diet (10% Calories from fat) and used as lean controls (n=10/group). After 12 weeks on the high fat diet, the APN KO mice weighed significantly more than the C57BL/6 mice (45.1±1.3 g vs 40.1±1.1 g, p=0.0008) but there was no difference in the final weights between genotypes fed the low fat diet. APN KO mice on both high and low fat diets for 12 weeks developed insulin resistance as measured by oral glucose tolerance test (Area under curve (AUC) mmol/L х min = 437±70 and 438±57) as compared to the C57BL/6 mice fed low or high fat diets (AUC mmol/L х min = 251±27 and 245±43). Arterial stiffness was determined by Doppler pulse wave velocity analysis of the femoral artery. Pulse wave velocity was increased in APN KO mice fed a high fat diet relative to those fed the low fat diet (12.56±0.78 cm/s vs 9.47±0.95 cm/s, p=0.0035; n=8-10). Pulse wave velocity was not different between C57BL/6 control mice on the low or high fat diets (10.63±0.73 cm/s and 10.86±0.50 cm/s), thus revealing that only mice deficient in adiponectin developed arterial stiffness in response to high fat diet. Conclusions: Potentiation of the vascular stiffness in diet-induced obese APN KO mice indicates that adiponectin has a role in modulating vascular structure and the APN KO mouse models the vascular changes that occur in human obesity and metabolic disorders. Morphometric analysis of the aortic tissues for vessel thickness and expression of extracellular proteins will further validate the potential role of adiponectin on the maintenance of arterial elasticity in addition to its known effect on eNOS mediated vasoprotection.


2018 ◽  
Vol 16 ◽  
pp. 205873921876094 ◽  
Author(s):  
Gang Yu ◽  
Lili Zhu ◽  
Haiyan Li ◽  
Youyou Shao ◽  
Lei Chong ◽  
...  

Overweight/obesity has been suggested as a risk factor for asthma development, and prospective studies have confirmed that high body weight precedes asthma symptoms. However, the nature of the association between overweight/obese status and asthma remains unclear. Animal models of obesity-related asthma are very useful for understanding disease pathophysiology. Although C57/B6J mice are the most widely used animal model for researching obesity-related asthma, gender differences are not always taken into consideration. Therefore, to explore the effect of gender on the development of obesity-related asthma, both female and male C57/B6J mice were used in this study. The mice were fed with a high-fat diet or a low-fat diet as control. Body weight, body length, liver weight, and Lee’s Index were used to evaluate obesity status, and lung histology, lung inflammatory cells infiltration, and inflammatory cytokines in bronchoalveolar lavage fluid (BALF) were examined for asthma evaluation. We found that the mean body weight of male mice on a high-fat diet gradually increased and was significantly higher than control male mice on a low-fat diet ( P < 0.01), while no significant differences were found between female mice at the end of 12 weeks of feeding. Furthermore, the obese asthma group female and male mice exhibited significantly high inflammatory cells infiltration than normal weight or obese female and male mice ( P < 0.01). However, the obese asthma group presented higher Neu infiltration, Th1 cytokine, and interferon gamma (IFNγ) concentrations in BALF than the asthma group in both the genders ( P < 0.01). In conclusion, both female and male mice are suitable for the obesity-related asthma model, although male mice might be more stable. Besides, obesity-related asthma is not Th2 type asthma.


1960 ◽  
Vol 198 (4) ◽  
pp. 765-770 ◽  
Author(s):  
Leon Sokoloff ◽  
Olaf Mickelsen ◽  
Emanuel Silverstein ◽  
George E. Jay ◽  
Richard S. Yamamoto

Experimental obesity was produced in DBA/2JN, STR/N and C57L/HeN mice as well as in Osborne-Mendel rats by several dietary regimens. One of these, containing 60% vegetable fat, increased the amount of degenerative joint disease in the rats and in two strains of mice. No increase of osteoarthritis occurred as a result of a 37.4% fat content in the diet, or from obesity produced by Ingle's diet, which has a relatively low-fat content. The mechanism by which the high-fat diet increased the joint disease is unknown, because neither obesity nor a high-fat diet alone had a deleterious effect on the articulations of the mice. Obese hybrid mice derived from a spontaneously obese and arthritis-prone strain (STR/1N) were resistant to articular degeneration. Dietary restriction of weight gain in the STR/1N mice failed to decrease the osteoarthritis in them.


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