Biochemical Phenomena, Metabolism, and Nutrition Commons^™

Modeling Age-Dependent Developmental Changes In The Expression Of Genes Involved In Citrulline Synthesis Using Pig Enteroids, Mahmoud A Mohammad, Inka C Didelija, Barbara Stoll, Douglas G Burrin, Juan C Marini

Children’s Nutrition Research Center Staff Publications

metabolism of citrulline and arginine are well characterized. Enteroids, a novel ex-vivo model that recreates the three-dimensional structure of the intestinal crypt-villus unit, have shown to replicate molecular and physiological profiles of the intestinal segment from where they originated ("location memory").

Objective: The present study tested the hypothesis that enteroids recapitulate the developmental changes observed in vivo regarding citrulline production in pigs ("developmental memory").

Methods: Preterm (10- and 5-d preterm) and term pigs at birth, together with 7- and 35-d-old pigs were studied. Gene expression was measured in jejunal samples and in enteroids derived from this segment. Whole body citrulline …

The Central Melanocortin System And Human Obesity, Yongjie Yang, Yong Xu

Children’s Nutrition Research Center Staff Publications

The prevalence of obesity and the associated comorbidities highlight the importance of understanding the regulation of energy homeostasis. The central melanocortin system plays a critical role in controlling body weight balance. Melanocortin neurons sense and integrate the neuronal and hormonal signals, and then send regulatory projections, releasing anorexigenic or orexigenic melanocortin neuropeptides, to downstream neurons to regulate the food intake and energy expenditure. This review summarizes the latest progress in our understanding of the role of the melanocortin pathway in energy homeostasis. We also review the advances in the identification of human genetic variants that cause obesity via mechanisms that …

Paraventricular Hypothalamus Mediates Diurnal Rhythm Of Metabolism, Eun Ran Kim, Yuanzhong Xu, Ryan M Cassidy, Yungang Lu, Yongjie Yang, Jinbin Tian, De-Pei Li, Rachel Van Drunen, Aleix Ribas-Latre, Zhao-Lin Cai, Mingshan Xue, Benjamin R Arenkiel, Kristin Eckel-Mahan, Yong Xu, Qingchun Tong

Children’s Nutrition Research Center Staff Publications

Defective rhythmic metabolism is associated with high-fat high-caloric diet (HFD) feeding, ageing and obesity; however, the neural basis underlying HFD effects on diurnal metabolism remains elusive. Here we show that deletion of BMAL1, a core clock gene, in paraventricular hypothalamic (PVH) neurons reduces diurnal rhythmicity in metabolism, causes obesity and diminishes PVH neuron activation in response to fast-refeeding. Animal models mimicking deficiency in PVH neuron responsiveness, achieved through clamping PVH neuron activity at high or low levels, both show obesity and reduced diurnal rhythmicity in metabolism. Interestingly, the PVH exhibits BMAL1-controlled rhythmic expression of GABA-A receptor γ2 subunit, and dampening …

Disrupted Hypothalamic Crh Neuron Responsiveness Contributes To Diet-Induced Obesity, Canjun Zhu, Yuanzhong Xu, Zhiying Jiang, Jin Bin Tian, Ryan M Cassidy, Zhao-Lin Cai, Gang Shu, Yong Xu, Mingshan Xue, Benjamin R Arenkiel, Qingyan Jiang, Qingchun Tong

Children’s Nutrition Research Center Staff Publications

The current obesity epidemic mainly results from high-fat high-caloric diet (HFD) feeding and may also be contributed by chronic stress; however, the neural basis underlying stress-related diet-induced obesity remains unknown. Corticotropin-releasing hormone (CRH) neurons in the paraventricular hypothalamus (PVH), a known body weight-regulating region, represent one key group of stress-responsive neurons. Here, we found that HFD feeding blunted PVH CRH neuron response to nutritional challenges as well as stress stimuli and dexamethesone, which normally produce rapid activation and inhibition on these neurons, respectively. We generated mouse models with the activity of these neurons clamped at high or low levels, both …

Parenteral Lipids Shape Gut Bile Acid Pools And Microbiota Profiles In The Prevention Of Cholestasis In Preterm Pigs, Lee Call, Tiffany Molina, Barbara Stoll, Greg Guthrie, Shaji Chacko, Jogchum Plat, Jason Robinson, Sen Lin, Caitlin Vonderohe, Mahmoud Mohammad, Dennis Kunichoff, Stephanie Cruz, Patricio Lau, Muralidhar Premkumar, Jon Nielsen, Zhengfeng Fang, Oluyinka Olutoye, Thomas Thymann, Robert Britton, Per Sangild, Douglas Burrin

Children’s Nutrition Research Center Staff Publications

Multi-component lipid emulsions, rather than soy-oil emulsions, prevent cholestasis by an unknown mechanism. Here, we quantified liver function, bile acid pools, and gut microbial and metabolite profiles in premature parenterally fed pigs given a soy-oil lipid emulsion, Intralipid (IL), a multi component lipid emulsion, SMOFlipid (SMOF), a novel emulsion with a modified fatty-acid composition [experimental emulsion (EXP)], or a control enteral diet (ENT) for 22 days. We assayed serum cholestasis markers, measured total bile acid levels in plasma, liver, and gut contents, and analyzed colonic bacterial 16S rRNA gene sequences and metabolomic profiles. Serum cholestasis markers (i.e., bilirubin, bile acids, …

Estrogen Receptor-Α Expressing Neurons In The Ventrolateral Vmh Regulate Glucose Balance, Yanlin He, Pingwen Xu, Chunmei Wang, Yan Xia, Meng Yu, Yongjie Yang, Kaifan Yu, Xing Cai, Na Qu, Kenji Saito, Julia Wang, Ilirjana Hyseni, Matthew Robertson, Badrajee Piyarathna, Min Gao, Sohaib A Khan, Feng Liu, Rui Chen, Cristian Coarfa, Zhongming Zhao, Qingchun Tong, Zheng Sun, Yong Xu

Children’s Nutrition Research Center Staff Publications

Brain glucose-sensing neurons detect glucose fluctuations and prevent severe hypoglycemia, but mechanisms mediating functions of these glucose-sensing neurons are unclear. Here we report that estrogen receptor-α (ERα)-expressing neurons in the ventrolateral subdivision of the ventromedial hypothalamic nucleus (vlVMH) can sense glucose fluctuations, being glucose-inhibited neurons (GI-ERαvlVMH) or glucose-excited neurons (GE-ERαvlVMH). Hypoglycemia activates GI-ERαvlVMH neurons via the anoctamin 4 channel, and inhibits GE-ERαvlVMH neurons through opening the ATP-sensitive potassium channel. Further, we show that GI-ERαvlVMH neurons preferentially project to the medioposterior arcuate nucleus of the hypothalamus (mpARH) and GE-ERαvlVMH neurons preferentially project to the dorsal Raphe nuclei (DRN). Activation of ERαvlVMH …

Steroid Receptor Coactivator-1 Modulates The Function Of Pomc Neurons And Energy Homeostasis, Yongjie Yang, Agatha A Van Der Klaauw, Liangru Zhu, Tessa M Cacciottolo, Yanlin He, Lukas K J Stadler, Chunmei Wang, Pingwen Xu, Kenji Saito, Antentor Hinton, Xiaofeng Yan, Julia M Keogh, Elana Henning, Matthew C Banton, Audrey E Hendricks, Elena G Bochukova, Vanisha Mistry, Katherine L Lawler, Lan Liao, Jianming Xu, Stephen O'Rahilly, Qingchun Tong, Uk10k Consortium, Inês Barroso, Bert W O'Malley, I Sadaf Farooqi, Yong Xu

Children’s Nutrition Research Center Staff Publications

Hypothalamic neurons expressing the anorectic peptide Pro-opiomelanocortin (Pomc) regulate food intake and body weight. Here, we show that Steroid Receptor Coactivator-1 (SRC-1) interacts with a target of leptin receptor activation, phosphorylated STAT3, to potentiate Pomc transcription. Deletion of SRC-1 in Pomc neurons in mice attenuates their depolarization by leptin, decreases Pomc expression and increases food intake leading to high-fat diet-induced obesity. In humans, fifteen rare heterozygous variants in SRC-1 found in severely obese individuals impair leptin-mediated Pomc reporter activity in cells, whilst four variants found in non-obese controls do not. In a knock-in mouse model of a loss of function …

Glutathione De Novo Synthesis But Not Recycling Process Coordinates With Glutamine Catabolism To Control Redox Homeostasis And Directs Murine T Cell Differentiation, Gaojian Lian, J. N. Rashida Gnanaprakasam, Tingting Wang, Ruohan Wu, Xuyong Chen, Lingling Liu, Yuqing Shen, Mao Yang, Jun Yang, Ying Chen, Vasilis Vasiliou, Teresa A. Cassel, Douglas R. Green, Yusen Liu, Teresa W. -M. Fan, Ruoning Wang

Toxicology and Cancer Biology Faculty Publications

Upon antigen stimulation, T lymphocytes undergo dramatic changes in metabolism to fulfill the bioenergetic, biosynthetic and redox demands of proliferation and differentiation. Glutathione (GSH) plays an essential role in controlling redox balance and cell fate. While GSH can be recycled from Glutathione disulfide (GSSG), the inhibition of this recycling pathway does not impact GSH content and murine T cell fate. By contrast, the inhibition of the de novo synthesis of GSH, by deleting either the catalytic (Gclc) or the modifier (Gclm) subunit of glutamate–cysteine ligase (Gcl), dampens intracellular GSH, increases ROS, and impact T cell differentiation. Moreover, the inhibition of …

Disturbance Of Redox Homeostasis In Down Syndrome: Role Of Iron Dysmetabolism, Eugenio Barone, Andrea Arena, Elizabeth Head, D. Allan Butterfield, Marzia Perluigi

Sanders-Brown Center on Aging Faculty Publications

Down syndrome (DS) is the most common genetic form of intellectual disability that leads in the majority of cases to development of early-onset Alzheimer-like dementia (AD). The neuropathology of DS has several common features with AD including alteration of redox homeostasis, mitochondrial deficits, and inflammation among others. Interestingly, some of the genes encoded by chromosome 21 are responsible of increased oxidative stress (OS) conditions that are further exacerbated by decreased antioxidant defense. Previous studies from our groups showed that accumulation of oxidative damage is an early event in DS neurodegeneration and that oxidative modifications of selected proteins affects the integrity …

Probing The Metabolic Phenotype Of Breast Cancer Cells By Multiple Tracer Stable Isotope Resolved Metabolomics, Andrew N. Lane, Julie Tan, Yali Wang, Jun Yan, Richard M. Higashi, Teresa W. -M. Fan

Center for Environmental and Systems Biochemistry Faculty Publications

Breast cancers vary by their origin and specific set of genetic lesions, which gives rise to distinct phenotypes and differential response to targeted and untargeted chemotherapies. To explore the functional differences of different breast cell types, we performed Stable Isotope Resolved Metabolomics (SIRM) studies of one primary breast (HMEC) and three breast cancer cells (MCF-7, MDAMB-231, and ZR75-1) having distinct genotypes and growth characteristics, using ¹³C₆-glucose, ¹³C-1+2-glucose, ¹³C₅,¹⁵N₂-Gln, ¹³C₃-glycerol, and ¹³C₈-octanoate as tracers. These tracers were designed to probe the central energy producing …

A Quantitative Lc-Ms/Ms Method For Simultaneous Determination Of Cocaine And Its Metabolites In Whole Blood, Xiabin Chen, Xirong Zheng, Kai Ding, Ziyuan Zhou, Chang-Guo Zhan, Fang Zheng

Molecular Modeling and Biopharmaceutical Center Faculty Publications

As new metabolic pathways of cocaine were recently identified, a high performance liquid chromatography tandem mass spectrometry (LC–MS/MS) method was developed to simultaneously determine cocaine and nine cocaine-related metabolites in whole blood samples. One-step solid phase extraction was used to extract all of the ten compounds and corresponding internal standards from blood samples. All compounds and internal standards extracted were separated on an Atlantis T3 (100 Å, 3 μm, 2.1 mm × 150 mm I.D) column and detected in positive ion and high sensitivity mode with multiple reaction monitoring. This method was validated for its sensitivity, linearity, specificity, accuracy, precision, …

Impact Of Individual Acute Phase Serum Amyloid A Isoforms On Hdl Metabolism In Mice, Myung-Hee Kim, Maria C. De Beer, Joanne M. Wroblewski, Richard J. Charnigo, Ailing Ji, Nancy R. Webb, Frederick C. De Beer, Deneys R. Van Der Westhuyzen

Internal Medicine Faculty Publications

The acute phase (AP) reactant serum amyloid A (SAA), an HDL apolipoprotein, exhibits pro-inflammatory activities, but its physiological function(s) are poorly understood. Functional differences between SAA1.1 and SAA2.1, the two major SAA isoforms, are unclear. Mice deficient in either isoform were used to investigate plasma isoform effects on HDL structure, composition, and apolipoprotein catabolism. Lack of either isoform did not affect the size of HDL, normally enlarged in the AP, and did not significantly change HDL composition. Plasma clearance rates of HDL apolipoproteins were determined using native HDL particles. The fractional clearance rates (FCRs) of apoA-I, apoA-II, and SAA were …

Non-Alcoholic Fatty Liver Disease Induces Signs Of Alzheimer’S Disease (Ad) In Wild-Type Mice And Accelerates Pathological Signs Of Ad In An Ad Model, Do-Geun Kim, Antje Krenz, Leon E. Toussaint, Kirk J. Maurer

Dartmouth Scholarship

Background: Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease afflicting about one third of the world's population and 30 % of the US population. It is induced by consumption of high-lipid diets and is characterized by liver inflammation and subsequent liver pathology. Obesity and consumption of a high-fat diet are known to increase the risk of Alzheimer's disease (AD). Here, we investigated NAFLD-induced liver inflammation in the pathogenesis of AD.

Methods: WT and APP-Tg mice were fed with a standard diet (SD) or a high-fat diet (HFD) for 2, 5 months, or 1 year to induce NAFLD. Another …

The Synergistic Roles Of Cholecystokinin B And Dopamine D5 Receptors On The Regulation Of Renal Sodium Excretion., Xiaoliang Jiang, Wei Chen, Xing Liu, Zihao Wang, Yunpeng Liu, Robin A Felder, John J Gildea, Pedro A. Jose, Chuan Qin, Zhiwei Yang

Medicine Faculty Publications

Renal dopamine D1-like receptors (D1R and D5R) and the gastrin receptor (CCKBR) are involved in the maintenance of sodium homeostasis. The D1R has been found to interact synergistically with CCKBR in renal proximal tubule (RPT) cells to promote natriuresis and diuresis. D5R, which has a higher affinity for dopamine than D1R, has some constitutive activity. Hence, we sought to investigate the interaction between D5R and CCKBR in the regulation of renal sodium excretion. In present study, we found D5R and CCKBR increase each other's expression in a concentration- and time-dependent manner in the HK-2 cell, the specificity of which was …

Redox Proteomic Identification Of Hne-Bound Mitochondrial Proteins In Cardiac Tissues Reveals A Systemic Effect On Energy Metabolism After Doxorubicin Treatment, Y. Zhao, Sumitra Miriyala, L. Miao, Mihail I. Mitov, David M. Schnell, Sanjit Kumar Dhar, J. Cai, J. B. Klein, Rukhsana Sultana, D. Allan Butterfield, Mary Vore, I. Batinic-Haberle, Subbarao Bondada, Daret K. St. Clair

Toxicology and Cancer Biology Faculty Publications

Doxorubicin (DOX), one of the most effective anticancer drugs, is known to generate progressive cardiac damage, which is due, in part, to DOX-induced reactive oxygen species (ROS). The elevated ROS often induce oxidative protein modifications that result in alteration of protein functions. This study demonstrates that the level of proteins adducted by 4-hydroxy-2-nonenal (HNE), a lipid peroxidation product, is significantly increased in mouse heart mitochondria after DOX treatment. A redox proteomics method involving two-dimensional electrophoresis followed by mass spectrometry and investigation of protein databases identified several HNE-modified mitochondrial proteins, which were verified by HNE-specific immunoprecipitation in cardiac mitochondria from the …

Role For Akt3/Protein Kinase Bγ In Attainment Of Normal Brain Size, Rachel M. Easton, Han Cho, Kristin Roovers, Diana W. Shineman

Dartmouth Scholarship

Studies of Drosophila and mammals have revealed the importance of insulin signaling through phosphatidylinositol 3-kinase and the serine/threonine kinase Akt/protein kinase B for the regulation of cell, organ, and organismal growth. In mammals, three highly conserved proteins, Akt1, Akt2, and Akt3, comprise the Akt family, of which the first two are required for normal growth and metabolism, respectively. Here we address the function of Akt3. Like Akt1, Akt3 is not required for the maintenance of normal carbohydrate metabolism but is essential for the attainment of normal organ size. However, in contrast to Akt1^−/− mice, which display a …

Multiple Metabolic Hits Converge On Cd36 As Novel Mediator Of Tubular Epithelial Apoptosis In Diabetic Nephropathy., Katalin Susztak, Emilio Ciccone, Peter Mccue, Kumar Sharma, Erwin P Böttinger

Department of Medicine Faculty Papers

BACKGROUND: Diabetic nephropathy (DNP) is a common complication of type 1 and type 2 diabetes mellitus and the most common cause of kidney failure. While DNP manifests with albuminuria and diabetic glomerulopathy, its progression correlates best with tubular epithelial degeneration (TED) and interstitial fibrosis. However, mechanisms leading to TED in DNP remain poorly understood.

METHODS AND FINDINGS: We found that expression of scavenger receptor CD36 coincided with proximal tubular epithelial cell (PTEC) apoptosis and TED specifically in human DNP. High glucose stimulated cell surface expression of CD36 in PTECs. CD36 expression was necessary and sufficient to mediate PTEC apoptosis induced …

Biochemical Enrichment And Biophysical Characterization Of A Taste Receptor For L-Arginine From The Catfish, Ictalurus Puntatus., William Grosvenor, Yuri Kaulin, Andrew I Spielman, Douglas L Bayley, D Lynn Kalinoski, John H Teeter, Joseph G Brand

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

BACKGROUND: The channel catfish, Ictalurus punctatus, is invested with a high density of cutaneous taste receptors, particularly on the barbel appendages. Many of these receptors are sensitive to selected amino acids, one of these being a receptor for L-arginine (L-Arg). Previous neurophysiological and biophysical studies suggested that this taste receptor is coupled directly to a cation channel and behaves as a ligand-gated ion channel receptor (LGICR). Earlier studies demonstrated that two lectins, Ricinus communis agglutinin I (RCA-I) and Phaseolus vulgaris Erythroagglutinin (PHA-E), inhibited the binding of L-Arg to its presumed receptor sites, and that PHA-E inhibited the L-Arg-stimulated ion conductance …