Other search tools

About this data

The publication data currently available has been vetted by Vanderbilt faculty, staff, administrators and trainees. The data itself is retrieved directly from NCBI's PubMed and is automatically updated on a weekly basis to ensure accuracy and completeness.

If you have any questions or comments, please contact us.

Results: 1 to 10 of 79

Publication Record

Connections

SIRT2 knockout exacerbates insulin resistance in high fat-fed mice.
Lantier L, Williams AS, Hughey CC, Bracy DP, James FD, Ansari MA, Gius D, Wasserman DH
(2018) PLoS One 13: e0208634
MeSH Terms: Acetylation, Animals, Diet, High-Fat, Energy Metabolism, Insulin, Insulin Resistance, Liver, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Mitochondria, Muscle, Skeletal, Phosphorylation, Proto-Oncogene Proteins c-akt, Sirtuin 2
Show Abstract · Added January 8, 2019
The NAD+-dependent deacetylase SIRT2 is unique amongst sirtuins as it is effective in the cytosol, as well as the mitochondria. Defining the role of cytosolic acetylation state in specific tissues is difficult since even physiological effects at the whole body level are unknown. We hypothesized that genetic SIRT2 knockout (KO) would lead to impaired insulin action, and that this impairment would be worsened in HF fed mice. Insulin sensitivity was tested using the hyperinsulinemic-euglycemic clamp in SIRT2 KO mice and WT littermates. SIRT2 KO mice exhibited reduced skeletal muscle insulin-induced glucose uptake compared to lean WT mice, and this impairment was exacerbated in HF SIRT2 KO mice. Liver insulin sensitivity was unaffected in lean SIRT2 KO mice. However, the insulin resistance that accompanies HF-feeding was worsened in SIRT2 KO mice. It was notable that the effects of SIRT2 KO were largely disassociated from cytosolic acetylation state, but were closely linked to acetylation state in the mitochondria. SIRT2 KO led to an increase in body weight that was due to increased food intake in HF fed mice. In summary, SIRT2 deletion in vivo reduces muscle insulin sensitivity and contributes to liver insulin resistance by a mechanism that is unrelated to cytosolic acetylation state. Mitochondrial acetylation state and changes in feeding behavior that result in increased body weight correspond to the deleterious effects of SIRT2 KO on insulin action.
2 Communities
1 Members
0 Resources
16 MeSH Terms
Role of Bile Acids and GLP-1 in Mediating the Metabolic Improvements of Bariatric Surgery.
Albaugh VL, Banan B, Antoun J, Xiong Y, Guo Y, Ping J, Alikhan M, Clements BA, Abumrad NN, Flynn CR
(2019) Gastroenterology 156: 1041-1051.e4
MeSH Terms: Anastomosis, Surgical, Animals, Anticholesteremic Agents, Bariatric Surgery, Bile Acids and Salts, Blood Glucose, Cholestyramine Resin, Diet, High-Fat, Gallbladder, Glucagon-Like Peptide 1, Glucagon-Like Peptide-1 Receptor, Glucose Tolerance Test, Ileum, Insulin Resistance, Intestines, Lymph, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Receptors, Cytoplasmic and Nuclear, Receptors, G-Protein-Coupled, Signal Transduction, Verrucomicrobia, Weight Loss
Show Abstract · Added January 4, 2019
BACKGROUND & AIMS - Bile diversion to the ileum (GB-IL) has strikingly similar metabolic and satiating effects to Roux-en-Y gastric bypass (RYGB) in rodent obesity models. The metabolic benefits of these procedures are thought to be mediated by increased bile acids, although parallel changes in body weight and other confounding variables limit this interpretation.
METHODS - Global G protein-coupled bile acid receptor-1 null (Tgr5) and intestinal-specific farnesoid X receptor null (Fxr) mice on high-fat diet as well as wild-type C57BL/6 and glucagon-like polypeptide 1 receptor deficient (Glp-1r) mice on chow diet were characterized following GB-IL.
RESULTS - GB-IL induced weight loss and improved oral glucose tolerance in Tgr5, but not Fxr mice fed a high-fat diet, suggesting a role for intestinal Fxr. GB-IL in wild-type, chow-fed mice prompted weight-independent improvements in glycemia and glucose tolerance secondary to augmented insulin responsiveness. Improvements were concomitant with increased levels of lymphatic GLP-1 in the fasted state and increased levels of intestinal Akkermansia muciniphila. Improvements in fasting glycemia after GB-IL were mitigated with exendin-9, a GLP-1 receptor antagonist, or cholestyramine, a bile acid sequestrant. The glucoregulatory effects of GB-IL were lost in whole-body Glp-1r mice.
CONCLUSIONS - Bile diversion to the ileum improves glucose homeostasis via an intestinal Fxr-Glp-1 axis. Altered intestinal bile acid availability, independent of weight loss, and intestinal Akkermansia muciniphila appear to mediate the metabolic changes observed after bariatric surgery and might be manipulated for treatment of obesity and diabetes.
Copyright © 2019 AGA Institute. Published by Elsevier Inc. All rights reserved.
0 Communities
2 Members
0 Resources
25 MeSH Terms
Attenuation of diet-induced hypothalamic inflammation following bariatric surgery in female mice.
Herrick MK, Favela KM, Simerly RB, Abumrad NN, Bingham NC
(2018) Mol Med 24: 56
MeSH Terms: Animals, Bariatric Surgery, Diet, High-Fat, Female, Hypothalamus, Inflammation, Mice, Inbred C57BL, Obesity
Show Abstract · Added April 11, 2019
BACKGROUND - Exposure of rodents to chronic high-fat diet (HFD) results in upregulation of inflammatory markers and proliferation of microglia within the mediobasal hypothalamus. Such hypothalamic inflammation is associated with metabolic dysfunction, central leptin resistance, and maintenance of obesity. Bariatric surgeries result in long-term stable weight loss and improved metabolic function. However, the effects of such surgical procedures on HFD-induced hypothalamic inflammation are unknown. We sought to characterize the effects of two bariatric surgical procedures, Roux-en-Y gastric bypass (RYGB) and biliary diversion (BD-IL), in female mice with particular emphasis on HFD-induced hypothalamic inflammation and microgliosis.
METHODS - RYGB and BD-IL were performed on diet-induced obese (DIO) mice. Quantitative RT-PCR and fluorescent microscopy were used to evaluate hypothalamic inflammatory gene expression and microgliosis. Results were compared to lean (CD), DIO sham-surgerized mice (DIO-SHAM), and dietary weight loss (DIO-Rev) controls.
RESULTS - In female mice, RYGB and BD-IL result in normalization of hypothalamic inflammatory gene expression and microgliosis within 8 weeks of surgery, despite ongoing exposure to HFD. Paralleling these results, the hypothalamic expression levels of the orexigenic neuropeptide Agrp and the anorexic response of surgical mice to exogenous leptin were comparable to lean controls (CD). In contrast, results from DIO-Rev mice were comparable to DIO-SHAM mice, despite transition back to standard rodent show and normalization of weight.
CONCLUSION - Bariatric surgery attenuates HFD-induced hypothalamic inflammation and microgliosis and restores leptin sensitivity, despite ongoing exposure to HFD.
0 Communities
1 Members
0 Resources
MeSH Terms
High CD8 T-Cell Receptor Clonality and Altered CDR3 Properties Are Associated With Elevated Isolevuglandins in Adipose Tissue During Diet-Induced Obesity.
McDonnell WJ, Koethe JR, Mallal SA, Pilkinton MA, Kirabo A, Ameka MK, Cottam MA, Hasty AH, Kennedy AJ
(2018) Diabetes 67: 2361-2376
MeSH Terms: Adipose Tissue, Animals, CD8-Positive T-Lymphocytes, Complementarity Determining Regions, Diet, High-Fat, Glucose Tolerance Test, Insulin Resistance, Liver, Male, Mice, Obesity, Prostaglandins
Show Abstract · Added March 26, 2019
Adipose tissue (AT) CD4 and CD8 T cells contribute to obesity-associated insulin resistance. Prior studies identified conserved T-cell receptor (TCR) chain families in obese AT, but the presence and clonal expansion of specific TCR sequences in obesity has not been assessed. We characterized AT and liver CD8 and CD4 TCR repertoires of mice fed a low-fat diet (LFD) and high-fat diet (HFD) using deep sequencing of the TCRβ chain to quantify clonal expansion, gene usage, and CDR3 sequence. In AT CD8 T cells, HFD reduced TCR diversity, increased the prevalence of public TCR clonotypes, and selected for TCR CDR3 regions enriched in positively charged and less polarized amino acids. Although TCR repertoire alone could distinguish between LFD- and HFD-fed mice, these properties of the CDR3 region of AT CD8 T cells from HFD-fed mice led us to examine the role of negatively charged and nonpolar isolevuglandin (isoLG) adduct-containing antigen-presenting cells within AT. IsoLG-adducted protein species were significantly higher in AT macrophages of HFD-fed mice; isoLGs were elevated in M2-polarized macrophages, promoting CD8 T-cell activation. Our findings demonstrate that clonal TCR expansion that favors positively charged CDR3s accompanies HFD-induced obesity, which may be an antigen-driven response to isoLG accumulation in macrophages.
© 2018 by the American Diabetes Association.
0 Communities
1 Members
0 Resources
MeSH Terms
Increases in bioactive lipids accompany early metabolic changes associated with β-cell expansion in response to short-term high-fat diet.
Seferovic MD, Beamish CA, Mosser RE, Townsend SE, Pappan K, Poitout V, Aagaard KM, Gannon M
(2018) Am J Physiol Endocrinol Metab 315: E1251-E1263
MeSH Terms: Animals, Blood Glucose, Cell Proliferation, Diabetes Mellitus, Type 2, Diet, High-Fat, Insulin Resistance, Insulin-Secreting Cells, Lipid Metabolism, Lipids, Liver, Male, Mice, Muscle, Skeletal, Obesity
Show Abstract · Added April 15, 2019
Pancreatic β-cell expansion is a highly regulated metabolic adaptation to increased somatic demands, including obesity and pregnancy; adult β cells otherwise rarely proliferate. We previously showed that high-fat diet (HFD) feeding induces mouse β-cell proliferation in less than 1 wk in the absence of insulin resistance. Here we metabolically profiled tissues from a short-term HFD β-cell expansion mouse model to identify pathways and metabolite changes associated with β-cell proliferation. Mice fed HFD vs. chow diet (CD) showed a 14.3% increase in body weight after 7 days; β-cell proliferation increased 1.75-fold without insulin resistance. Plasma from 1-wk HFD-fed mice induced β-cell proliferation ex vivo. The plasma, as well as liver, skeletal muscle, and bone, were assessed by LC and GC mass-spectrometry for global metabolite changes. Of the 1,283 metabolites detected, 159 showed significant changes [false discovery rate (FDR) < 0.1]. The majority of changes were in liver and muscle. Pathway enrichment analysis revealed key metabolic changes in steroid synthesis and lipid metabolism, including free fatty acids and other bioactive lipids. Other important enrichments included changes in the citric acid cycle and 1-carbon metabolism pathways implicated in DNA methylation. Although the minority of changes were observed in bone and plasma (<20), increased p-cresol sulfate was increased >4 fold in plasma (the largest increase in all tissues), and pantothenate (vitamin B) decreased >2-fold. The results suggest that HFD-mediated β-cell expansion is associated with complex, global metabolite changes. The finding could be a significant insight into Type 2 diabetes pathogenesis and potential novel drug targets.
0 Communities
1 Members
0 Resources
14 MeSH Terms
Brief exposure to obesogenic diet disrupts brain dopamine networks.
Barry RL, Byun NE, Williams JM, Siuta MA, Tantawy MN, Speed NK, Saunders C, Galli A, Niswender KD, Avison MJ
(2018) PLoS One 13: e0191299
MeSH Terms: Amphetamine, Animals, Brain, Diet, High-Fat, Dopamine, Insulin, Male, Neostriatum, Nerve Net, Obesity, Rats, Rats, Sprague-Dawley, Receptors, Dopamine D2, Signal Transduction, Time Factors
Show Abstract · Added April 11, 2019
OBJECTIVE - We have previously demonstrated that insulin signaling, through the downstream signaling kinase Akt, is a potent modulator of dopamine transporter (DAT) activity, which fine-tunes dopamine (DA) signaling at the synapse. This suggests a mechanism by which impaired neuronal insulin receptor signaling, a hallmark of diet-induced obesity, may contribute to impaired DA transmission. We tested whether a short-term (two-week) obesogenic high-fat (HF) diet could reduce striatal Akt activity, a marker of central insulin, receptor signaling and blunt striatal and dopaminergic network responsiveness to amphetamine (AMPH).
METHODS - We examined the effects of a two-week HF diet on striatal DAT activity in rats, using AMPH as a probe in a functional magnetic resonance imaging (fMRI) assay, and mapped the disruption in AMPH-evoked functional connectivity between key dopaminergic targets and their projection areas using correlation and permutation analyses. We used phosphorylation of the Akt substrate GSK3α in striatal extracts as a measure of insulin receptor signaling. Finally, we confirmed the impact of HF diet on striatal DA D2 receptor (D2R) availability using [18F]fallypride positron emission tomography (PET).
RESULTS - We found that rats fed a HF diet for only two weeks have reductions in striatal Akt activity, a marker of decreased striatal insulin receptor signaling and blunted striatal responsiveness to AMPH. HF feeding also reduced interactions between elements of the mesolimbic (nucleus accumbens-anterior cingulate) and sensorimotor circuits (caudate/putamen-thalamus-sensorimotor cortex) implicated in hedonic feeding. D2R availability was reduced in HF-fed animals.
CONCLUSION - These studies support the hypothesis that central insulin signaling and dopaminergic neurotransmission are already altered after short-term HF feeding. Because AMPH induces DA efflux and brain activation, in large part via DAT, these findings suggest that blunted central nervous system insulin receptor signaling through a HF diet can impair DA homeostasis, thereby disrupting cognitive and reward circuitry involved in the regulation of hedonic feeding.
0 Communities
1 Members
0 Resources
MeSH Terms
Balanced high fat diet reduces cardiovascular risk in obese women although changes in adipose tissue, lipoproteins, and insulin resistance differ by race.
Niswender KD, Fazio S, Gower BA, Silver HJ
(2018) Metabolism 82: 125-134
MeSH Terms: Adipose Tissue, Adult, African Continental Ancestry Group, Cardiovascular Diseases, Diet, High-Fat, European Continental Ancestry Group, Female, Humans, Insulin Resistance, Lipoproteins, Middle Aged, Obesity, Risk Factors, Young Adult
Show Abstract · Added April 10, 2018
BACKGROUND - We previously reported that consuming a balanced high fat diet (BHFD) wherein total saturated fat was reduced and total unsaturated fat increased by proportionately balancing the type of fat (1/3 saturated, 1/3 monounsaturated, 1/3 polyunsaturated) led to significant improvements in inflammatory burden, blood pressure, and vascular function in obese premenopausal European American (EA) and African American (AA) women.
OBJECTIVE - Here we compared changes in adipose tissue, lipoproteins, insulin resistance, and cardiovascular risk between EA and AA women.
METHODS - Dietary intakes, plasma fatty acids, lipids, apolipoproteins, lipoproteins, HOMA-IR and ASCVD risk was measured in 144 women who consumed BHFD for 16 weeks. Generalized linear modeling was performed while controlling for change in body weight.
RESULTS - EA women had greater reductions in visceral adipose tissue. Only EA women had significant reductions in fasting insulin levels (↓24.8%) and HOMA-IR (↓29%) scores. In EA women, the most significant improvements occurred in VLDL particle size (↑), apolipoprotein B levels (↑), serum TG (↓), number of plasma LDL particles (↓), and serum LDL-cholesterol (↓). In AA women, significant improvements occurred in HDL particle size (↑), number of large HDL particles (↑), and apolipoprotein AI levels (↑). Consequently, both groups had improved ASCVD risk scores (↓5.5%).
CONCLUSIONS - Consuming the balanced high fat diet led to significant reduction in cardiovascular risk factors in both groups. However, the pattern of response to BHFD differed with EA women responding more in components of the apolipoprotein B pathway versus AA women responding more in components of the apolipoprotein AI pathway.
Published by Elsevier Inc.
0 Communities
1 Members
0 Resources
14 MeSH Terms
Cooperative function of Pdx1 and Oc1 in multipotent pancreatic progenitors impacts postnatal islet maturation and adaptability.
Kropp PA, Dunn JC, Carboneau BA, Stoffers DA, Gannon M
(2018) Am J Physiol Endocrinol Metab 314: E308-E321
MeSH Terms: Adaptation, Physiological, Animals, Animals, Newborn, Cell Differentiation, Cells, Cultured, Diet, High-Fat, Gene Expression Regulation, Developmental, Glucose, Hepatocyte Nuclear Factor 6, Homeodomain Proteins, Insulin-Secreting Cells, Islets of Langerhans, Male, Mice, Mice, Transgenic, Multipotent Stem Cells, Organogenesis, Trans-Activators
Show Abstract · Added April 15, 2019
The transcription factors pancreatic and duodenal homeobox 1 (Pdx1) and onecut1 (Oc1) are coexpressed in multipotent pancreatic progenitors (MPCs), but their expression patterns diverge in hormone-expressing cells, with Oc1 expression being extinguished in the endocrine lineage and Pdx1 being maintained at high levels in β-cells. We previously demonstrated that cooperative function of these two factors in MPCs is necessary for proper specification and differentiation of pancreatic endocrine cells. In those studies, we observed a persistent decrease in expression of the β-cell maturity factor MafA. We therefore hypothesized that Pdx1 and Oc1 cooperativity in MPCs impacts postnatal β-cell maturation and function. Here our model of Pdx1-Oc1 double heterozygosity was used to investigate the impact of haploinsufficiency for both of these factors on postnatal β-cell maturation, function, and adaptability. Examining mice at postnatal day (P) 14, we observed alterations in pancreatic insulin content in both Pdx1 heterozygotes and double heterozygotes. Gene expression analysis at this age revealed significantly decreased expression of many genes important for glucose-stimulated insulin secretion (e.g., Glut2, Pcsk1/2, Abcc8) exclusively in double heterozygotes. Analysis of P14 islets revealed an increase in the number of mixed islets in double heterozygotes. We predicted that double-heterozygous β-cells would have an impaired ability to respond to stress. Indeed, we observed that β-cell proliferation fails to increase in double heterozygotes in response to either high-fat diet or placental lactogen. We thus report here the importance of cooperation between regulatory factors early in development for postnatal islet maturation and adaptability.
0 Communities
1 Members
0 Resources
MeSH Terms
High-Fat, High-Sugar Diet-Induced Subendothelial Matrix Stiffening is Mitigated by Exercise.
Kohn JC, Azar J, Seta F, Reinhart-King CA
(2018) Cardiovasc Eng Technol 9: 84-93
MeSH Terms: Animals, Aorta, Abdominal, Arterial Pressure, Diet, High-Fat, Dietary Sugars, Disease Models, Animal, Elastic Modulus, Exercise Therapy, Extracellular Matrix, Healthy Diet, Male, Mice, Inbred C57BL, Microscopy, Atomic Force, Peripheral Arterial Disease, Pulse Wave Analysis, Risk Reduction Behavior, Time Factors, Vascular Stiffness
Show Abstract · Added December 7, 2017
Consumption of a high-fat, high-sugar diet and sedentary lifestyle are correlated with bulk arterial stiffening. While measurements of bulk arterial stiffening are used to assess cardiovascular health clinically, they cannot account for changes to the tissue occurring on the cellular scale. The compliance of the subendothelial matrix in the intima mediates vascular permeability, an initiating step in atherosclerosis. High-fat, high-sugar diet consumption and a sedentary lifestyle both cause micro-scale subendothelial matrix stiffening, but the impact of these factors in concert remains unknown. In this study, mice on a high-fat, high-sugar diet were treated with aerobic exercise or returned to a normal diet. We measured bulk arterial stiffness through pulse wave velocity and subendothelial matrix stiffness ex vivo through atomic force microscopy. Our data indicate that while diet reversal mitigates high-fat, high-sugar diet-induced macro- and micro-scale stiffening, exercise only significantly decreases micro-scale stiffness and not macro-scale stiffness, during the time-scale studied. These data underscore the need for both healthy diet and exercise to maintain vascular health. These data also indicate that exercise may serve as a key lifestyle modification to partially reverse the deleterious impacts of high-fat, high-sugar diet consumption, even while macro-scale stiffness indicators do not change.
1 Communities
1 Members
0 Resources
18 MeSH Terms
HDAC3 is a molecular brake of the metabolic switch supporting white adipose tissue browning.
Ferrari A, Longo R, Fiorino E, Silva R, Mitro N, Cermenati G, Gilardi F, Desvergne B, Andolfo A, Magagnotti C, Caruso D, Fabiani E, Hiebert SW, Crestani M
(2017) Nat Commun 8: 93
MeSH Terms: Adipocytes, Adipose Tissue, Brown, Adipose Tissue, White, Animals, Cell Line, Diet, High-Fat, Gene Expression Regulation, Gene Silencing, Histone Deacetylases, Lipid Metabolism, Male, Mice, Mice, Knockout
Show Abstract · Added February 7, 2019
White adipose tissue (WAT) can undergo a phenotypic switch, known as browning, in response to environmental stimuli such as cold. Post-translational modifications of histones have been shown to regulate cellular energy metabolism, but their role in white adipose tissue physiology remains incompletely understood. Here we show that histone deacetylase 3 (HDAC3) regulates WAT metabolism and function. Selective ablation of Hdac3 in fat switches the metabolic signature of WAT by activating a futile cycle of de novo fatty acid synthesis and β-oxidation that potentiates WAT oxidative capacity and ultimately supports browning. Specific ablation of Hdac3 in adipose tissue increases acetylation of enhancers in Pparg and Ucp1 genes, and of putative regulatory regions of the Ppara gene. Our results unveil HDAC3 as a regulator of WAT physiology, which acts as a molecular brake that inhibits fatty acid metabolism and WAT browning.Histone deacetylases, such as HDAC3, have been shown to alter cellular metabolism in various tissues. Here the authors show that HDAC3 regulates WAT metabolism by activating a futile cycle of fatty acid synthesis and oxidation, which supports WAT browning.
1 Communities
0 Members
0 Resources
MeSH Terms