DOCSLIB.ORG

Cellular Changes in Lipid Metabolism in Response to Altered Energy Balance and Heat Stress in Lactating Dairy Cows Ma

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Cellular Changes in Lipid Metabolism in Response to Altered Energy Balance and Heat Stress in Lactating Dairy Cows Ma Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2015 Cellular changes in lipid metabolism in response to altered energy balance and heat stress in lactating dairy cows Ma. Pia Pagkaliwagan Faylon Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Agriculture Commons, Animal Sciences Commons, Cell Biology Commons, and the Genetics Commons Recommended Citation Faylon, Ma. Pia Pagkaliwagan, "Cellular changes in lipid metabolism in response to altered energy balance and heat stress in lactating dairy cows" (2015). Graduate Theses and Dissertations. 14303. https://lib.dr.iastate.edu/etd/14303 This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Cellular changes in lipid metabolism in response to altered energy balance and heat stress in lactating dairy cows by Ma. Pia P. Faylon A thesis submitted to the graduate faculty in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Major: Animal Breeding and Genetics Program of Study Committee: Diane M. Spurlock, Major Professor Lance H. Baumgard Jack C. M. Dekkers Michael E. Spurlock Iowa State University Ames, Iowa 2015 ii TABLE OF CONTENTS LIST OF TABLES …………………………………………….…………..………….. iv LIST OF FIGURES ………………………………………………………..…..…...… v LIST OF ABBREVIATIONS …………………………………………..…………..… vi ABSTRACT ………………………………………………………………………..… viii CHAPTER 1: INTRODUCTION Background ……………………………………….……………………………..……. 1 Objectives ……………………………………..…...…………………….….………... 3 CHAPTER 2: LITERATURE REVIEW Climate Change and Agriculture ………………………………...………....………… 5 Causes of Climate Change ……………………………………..………………... 5 Heat Stress and Its Effects on Animals ………………………………………….. 6 Heat Stress in Dairy Cattle ……………………………...…..……..…..…….……….. 8 Heat Stress Effects on Lactation …………………………………...……………. 9 Heat Stress Effects on Reproduction …………………………….....………….... 11 Heat Stress Effects on Metabolism ……………………………..…………….…. 13 Adipose Tissue Metabolism …………………...……………………..….. ..………… 15 CHAPTER 3: REGULATION OF LIPID-ASSOCIATED PROTEINS FOLLOWING GROWTH HORMONE ADMINISTRATION AND FEED RESTRICTION IN LACTATING HOLSTEIN COWS Abstract ……………………………………………………………..…..…………….. 22 Introduction ………………………………………………………..………….………. 23 Materials and Methods ………………………………………………………..…….... 25 Animals ………………………………………………………...…..……………. 25 Feed Restriction (FR) ………………………………………………….…… 26 Growth Hormone (GH) Administration …………………………..………... 26 Semi-Quantitative Western Blotting …………………………………….....……. 27 Data Analysis …………………………………...…………………………..…… 28 Results ……………………………………………..………………………………...... 29 Milk Production, Energy Balance and NEFA Concentration ………………….... 29 Lipolytic Proteins ………………..…………………………………………...….. 29 Discussion …………………………..……………………………………………….... 30 Conclusions ……………………………..…………………………………………...... 35 iii CHAPTER 4: EFFECTS OF HEAT STRESS ON LIPID METABOLISM OF BOVINE PRIMARY ADIPOCYTES Abstract ……………………………...……………………………..…………...……… 40 Introduction ………………………………………………………..…………..………. 42 Materials and Methods …………………………………………………………………. 44 Animals and Adipose Tissue Biopsy ……………………………………………… 44 Isolation of Adipocytes ……………………………………………………………. 45 Experimental Treatments ………………………………………………………….. 45 Validation Studies ……………………………………………………………. 45 Lipolysis Experiments ……………………………………………………….. 46 Lipogenesis Experiment ………………………………………………..……. 47 Glycerol Assay …………………………………………………...……………….. 48 Protein extraction and Semi-Quantitiative Western Blotting ……………………... 48 Calculations and Statistical Analysis ……………………………………………… 49 Results ………………………………………………………………………………….. 50 Analysis of HSP27 and Cell Viability …………………………………………….. 50 Effects of Heat Stress on Isoproterenol Response ………………………………… 51 Heat Stress on Stimulated Lipolysis Relative to Insulin ………………………….. 51 Changes in Lipolytic Proteins in Response to Heat Stress ………………………... 52 Effects of Heat Stress on Lipogenesis ………………………………………...…... 53 Discussion ……………………………………………...………………………………. 54 CHAPTER 5: INTEGRATIVE SUMMARY ………………………………………...... 68 LITERATURE CITED ……………………………………………………...…………. 71 iv LIST OF TABLES Table 3.1: Antibodies used for semi-quantitative Western blotting …..………..…….. 36 Table 3.2: Changes in abundance or phosphorylation of lipolytic proteins …..………. 37 v LIST OF FIGURES Figure 2.1: Lipolysis mediated through the protein kinase A (PKA) pathway.……..... 21 Figure 3.1: Abundance of lipid droplet associated proteins in subcutaneous adipose tissue in response to feed restriction ……………………………………....…………... 38 Figure 3.2: Abundance of lipid droplet associated proteins in subcutaneous adipose tissue in response to growth hormone administration determined via semi-quantitative Western blotting ………………………..……………………...………….…………… 39 Figure 4.1: Cell viability assay and analysis of HSP27 protein abundance ………….. 61 Figure 4.2: Effect of heat stress (HS) on lipolytic response ……………………..…… 62 Figure 4.3: Effect of heat stress (HS) on inhibition of stimulated lipolysis by low (4.5 x 10-7 M) and high (1 x 10-6 M) levels of insulin …………………………………..….. 63 Figure 4.4: Protein abundance of hormone sensitive lipase phosphorylated at Serine 563 (PHSLSer563) relative to increasing isoproterenol concentration ………………...... 64 Figure 4.5: Protein abundance of adipose triglyceride lipase (ATGL), perilipin (PLIN) and phosphorylated perilipin (PPLIN) relative to increasing isoproterenol concentration …………………………………………………………………………... 65 Figure 4.6: Protein abundance of hormone sensitive lipase phosphorylated at Serine residue 563 (PHSLSer563) and perilipin (PLIN) with increasing insulin concentration ... 66 Figure 4.7: Effect of insulin on rate of incorporation of radiolabeled acetate and phosphorylation of acetyl CoA carboxylase in primary bovine adipocytes ………....... 67 vi LIST OF ABBREVIATIONS A1R = ADENOSINE A1 RECEPTOR ACC = ACETYL CoA CARBOXYLASE ADA = ADENOSINE DEAMINASE ATGL = ADIPOSE TRIACYLGLYCERIDE LIPASE ATP = ADENOSINE TRIPHOSPHATE BAR = BETA-ADRENERGIC RECEPTOR BCA = BICINCHONINIC ASSAY BCS = BODY CONDITION SCORE BLAST = BASIC LOCAL ALIGNMENT SEARCH TOOL BSA = BOVINE SERUM ALBUMIN cAMP = CYCLIC ADENOSINE MONOPHOSPHATE CGI-58 = COMPARATIVE GENE IDENTITY-58 CH4 = METHANE CO2 = CARBON DIOXIDE CPT-1 = CARNITINE PALMITOYLTRANSFERASE-1 DAG = DIACYGLYCEROL DMEM = DULBECCO’S MODIFIED EAGLE MEDIUM DMI = DRY MATTER INTAKE EC50 = HALF MAXIMAL EFFECTIVE CONCENTRATION EDTA = ETHYLENEDIAMINETETRAACETIC ACID FA = FATTY ACID FR = FEED RESTRICTION FSH = FOLLICLE-STIMULATING HORMONE G-3-PDH = GLYCEROL-3-PHOSPHATE DEHYDROGENASE G-6-PDH = GLUCOSE-6-PHOSPHATE DEHYDROGENASE GH = GROWTH HORMONE HEPES = 4-(2-HYDROXYETHYL)-1-PIPERAZINEETHANESULFONIC ACID HS = HEAT STRESS HSL = HORMONE SENSITIVE LIPASE HSP27 = HEAT SHOCK PROTEIN 27 HSP70 = HEAT SHOCK PROTEIN 70 IC50 = HALF MAXIMAL INHIBITORY CONCENTRATION IgG = IMMUNOGLOBULIN G ISO = ISOPROTERENOL LD = LIPID DROPLET LH = LUTEINIZING HORMONE MAG = MONOACYLGLYCEROL MGL = MONOACYLGLYCEROL LIPASE N2O = NITROUS OXIDE NaCl = SODIUM CHLORIDE vii NADPH = NICOTINAMIDE ADENINE DINUCLEOTIDE PHOSPHATE NEBAL = NEGATIVE ENERGY BALANCE NEFA = NON-ESTERIFIED FATTY ACID NEL = NET ENERGY FOR LACTATION P-ACC = PHOSPHORYLATED ACETYL CoA CARBOXYLASE P1 = PHOSPHATASE 1 PDE3B = PHOSPHODIESTERASE-3-B PFTN = PAIR FED THERMAL NEUTRAL PHSLSer563 = PHOSPHORYLATED HORMONE SENSITIVE LIPASE AT SERINE RESIDUE 563 PHSLSer565 = PHOSPHORYLATED HORMONE SENSITIVE LIPASE AT SERINE RESIDUE 565 PKA = PROTEIN KINASE A PLIN = PERILIPIN PPLIN = PHOSPHORYLATED PERILIPIN Rmax = MAXIMAL RESPONSE RPL32 = RIBOSOMAL PROTEIN L32 TAG = TRIACYLGLYCERIDE THI = TEMPERATURE HUMIDITY INDEX TMR = TOTAL MIXED RATION TN = THERMAL NEUTRAL TNZ = THERMAL NEUTRAL ZONE viii ABSTRACT The dairy industry has evolved through the years. There is a need to continuously improve on selective breeding programs and management strategies in order to produce superior animals that could meet the increasing demands for food as well as adapt to the changing environment. Currently, a substantial amount of research has focused on the metabolic and physiological adaptations observed in dairy cows, particularly involving changes in energy balance during lactation. Studies described herein are designed to elucidate metabolic changes in the lactating cow, with particular regard to adipose tissue metabolism, and determine how these changes observed at the cellular level could potentially contribute to the animal’s adaptive process. Study 1 focused on the regulation of lipolytic proteins in 2 different models of altered energy balance achieved via feed restriction and growth hormone administration. Data show that multiple mechanisms regulate lipolysis, resulting in changes in abundance and phosphorylation of various lipolytic proteins. Study 2 evaluated the direct impacts of heat stress on lipid metabolism in vitro, relative to the presence of a beta-agonist and insulin. Results suggest that acute heat stress directly increases the response of primary bovine adipocytes to lipolytic but not lipogenic stimuli, and that increased insulin sensitivity observed in heat-stressed cells may potentially contribute to the diminished lipolytic response observed in vivo. 1 CHAPTER 1: INTRODUCTION Background Energy balance is one
Load more

Recommended publications
  • Effects of Glucagon, Glycerol, and Glucagon Plus Glycerol On
    Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2011 Effects of glucagon, glycerol, and glucagon plus glycerol on gluconeogenesis, lipogenesis, and lipolysis in periparturient Holstein cows Nimer Mehyar Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Biochemistry, Biophysics, and Structural Biology Commons Recommended Citation Mehyar, Nimer, "Effects of glucagon, glycerol, and glucagon plus glycerol on gluconeogenesis, lipogenesis, and lipolysis in periparturient Holstein cows" (2011). Graduate Theses and Dissertations. 11923. https://lib.dr.iastate.edu/etd/11923 This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Effects of glucagon, glycerol, and glucagon plus glycerol on gluconeogenesis, lipogenesis, and lipolysis in periparturient Holstein cows by Nimer Mehyar A thesis submitted to graduate faculty in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Major: Biochemistry Program of Study Committee: Donald C. Beitz, Major Professor Ted W. Huiatt Kenneth J. Koehler Iowa State University Ames, Iowa 2011 Copyright Nimer Mehyar, 2011. All rights reserved ii To My Mother To Ghada Ali, Sarah, and Hassan
    [Show full text]
  • THE AEROBIC (Air-Robic!) PATHWAYS
    THE AEROBIC (air-robic!) PATHWAYS Watch this video on aerobic glycolysis: http://ow.ly/G5djv Watch this video on oxygen use: http://ow.ly/G5dmh Energy System 1 – The Aerobic Use of Glucose (Glycolysis) This energy system involves the breakdown of glucose (carbohydrate) to release energy in the presence of oxygen. The key to this energy system is that it uses OXYGEN to supply energy. Just like the anaerobic systems, there are many negatives and positives from using this pathway. Diagram 33 below summarises the key features of this energy system. When reading the details on the table keep in mind the differences between this and the previous systems that were looked at. In this way a perspective of their features can be appreciated and applied. Diagram 33: The Key Features of the Aerobic Glycolytic System Highlight 3 key features in the diagram that are important to the functioning of this system. 1: ------------------------------------------------------------------------------------------------------------------------------------------------------- 2: ------------------------------------------------------------------------------------------------------------------------------------------------------- 3: ------------------------------------------------------------------------------------------------------------------------------------------------------- Notes ---------------------------------------------------------------------------------------------------------------------------------------------------------- ----------------------------------------------------------------------------------------------------------------------------------------------------------
    [Show full text]
  • Corticosteroid Treatment, Serum Lipids and Coronary Artery Disease D. B. JEFFERYS M
    Postgrad Med J: first published as 10.1136/pgmj.56.657.491 on 1 July 1980. Downloaded from Postgraduate Medical Journal (July 1980) 56, 491-493 Corticosteroid treatment, serum lipids and coronary artery disease D. B. JEFFERYS M. H. LESSOF B.Sc., M.R.C.P. M.D., F.R.C.P. M. B. MATTOCK Ph.D. Department of Medicine, Guy's Hospital, London Bridge SE] 9RT Summary cholesterol out of the tissue and back into the general Serum lipids and the cholesterol concentrations in the metabolic pool, where it may be catabolized. high density lipoprotein (HDL) fractions were meas- In this study the authors have looked at the long- ured in patients receiving long-term corticosteroid term effects of corticosteroids on HDL cholesterol. treatment for connective tissue disorders and asthma. They have studied 3 groups: patients who are receiv- Patients who were not receiving corticosteroid ing corticosteroids; age-, sex- and disease-matched treatment had blood lipid levels which did not differ patients who are not receiving such treatment; and from those of healthy people. However, female (but healthy age- and sex-matched controls. not male) patients who had received prednisolone for a mean period of 3-1 years had a significant elevation Patients and methods in total cholesterol and a large decrease in HDL Subjects cholesterol. It seems possible that high levels of The serum total cholesterol, triglycerides and copyright. corticosteroids may increase the incidence of pre- HDL cholesterol were measured for 16 pre-meno- menopausal ischaemic heart disease in females. pausal female patients (age range 18-34 years) and 15 males (ages 24-38 years) who were all receiving Introduction long-term corticosteroid treatment.
    [Show full text]
  • Adipocyte Glucocorticoid Receptor Is Important in Lipolysis and Insulin Resistance Due to Exogenous Steroids, but Not Insulin Resistance Caused by High Fat Feeding
    Adipocyte glucocorticoid receptor is important in lipolysis and insulin resistance due to exogenous steroids, but not insulin resistance caused by high fat feeding The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters Citation Shen, Yachen, Hyun Cheol Roh, Manju Kumari, and Evan D. Rosen. 2017. “Adipocyte glucocorticoid receptor is important in lipolysis and insulin resistance due to exogenous steroids, but not insulin resistance caused by high fat feeding.” Molecular Metabolism 6 (10): 1150-1160. doi:10.1016/j.molmet.2017.06.013. http:// dx.doi.org/10.1016/j.molmet.2017.06.013. Published Version doi:10.1016/j.molmet.2017.06.013 Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:34492181 Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Other Posted Material, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of- use#LAA Original Article Adipocyte glucocorticoid receptor is important in lipolysis and insulin resistance due to exogenous steroids, but not insulin resistance caused by high fat feeding Yachen Shen 1,4,5, Hyun Cheol Roh 1,5, Manju Kumari 1, Evan D. Rosen 1,2,3,* ABSTRACT Objective: The critical role of adipose tissue in energy and nutrient homeostasis is influenced by many external factors, including overnutrition, inflammation, and exogenous hormones. Prior studies have suggested that glucocorticoids (GCs) in particular are major drivers of physiological and pathophysiological changes in adipocytes. In order to determine whether these effects directly require the glucocorticoid receptor (GR) within adipocytes, we generated adipocyte-specific GR knockout (AGRKO) mice.
    [Show full text]
  • Tricarboxylic Acid (TCA) Cycle Intermediates: Regulators of Immune Responses
    life Review Tricarboxylic Acid (TCA) Cycle Intermediates: Regulators of Immune Responses Inseok Choi , Hyewon Son and Jea-Hyun Baek * School of Life Science, Handong Global University, Pohang, Gyeongbuk 37554, Korea; [email protected] (I.C.); [email protected] (H.S.) * Correspondence: [email protected]; Tel.: +82-54-260-1347 Abstract: The tricarboxylic acid cycle (TCA) is a series of chemical reactions used in aerobic organisms to generate energy via the oxidation of acetylcoenzyme A (CoA) derived from carbohydrates, fatty acids and proteins. In the eukaryotic system, the TCA cycle occurs completely in mitochondria, while the intermediates of the TCA cycle are retained inside mitochondria due to their polarity and hydrophilicity. Under cell stress conditions, mitochondria can become disrupted and release their contents, which act as danger signals in the cytosol. Of note, the TCA cycle intermediates may also leak from dysfunctioning mitochondria and regulate cellular processes. Increasing evidence shows that the metabolites of the TCA cycle are substantially involved in the regulation of immune responses. In this review, we aimed to provide a comprehensive systematic overview of the molecular mechanisms of each TCA cycle intermediate that may play key roles in regulating cellular immunity in cell stress and discuss its implication for immune activation and suppression. Keywords: Krebs cycle; tricarboxylic acid cycle; cellular immunity; immunometabolism 1. Introduction The tricarboxylic acid cycle (TCA, also known as the Krebs cycle or the citric acid Citation: Choi, I.; Son, H.; Baek, J.-H. Tricarboxylic Acid (TCA) Cycle cycle) is a series of chemical reactions used in aerobic organisms (pro- and eukaryotes) to Intermediates: Regulators of Immune generate energy via the oxidation of acetyl-coenzyme A (CoA) derived from carbohydrates, Responses.
    [Show full text]
  • Glycolysis and Glyceroneogenesis In
    GLYCOLYSIS AND GLYCERONEOGENESIS IN ADIPOCYTES: EFFECTS OF ROSIGLITAZONE, AN ANTI-DIABETIC DRUG By SOREIYU UMEZU Bachelor of Science in Biochemistry and Molecular Biology Oklahoma State University Stillwater, OK 2005 Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of DOCTOR OF PHILOSOPHY July, 2010 GLYCOLYSIS AND GLYCERONEOGENESIS IN ADIPOCYTES: EFFECTS OF ROSIGLITAZONE, AN ANTI-DIABETIC DRUG Dissertation Approved: Dr. Jose L Soulages Dissertation Adviser Dr. Chang-An Yu Dr. Andrew Mort Dr. Jack Dillwith Dr. A. Gordon Emslie Dean of the Graduate College ii ACKNOWLEDGMENTS First, I would like to immensely thank my advisor, Dr. Jose Soulages, for his support and guidance throughout my graduate studies. Without Dr. Soulages extensive expertise and knowledge along with his sense of humor I would not have achieved my goal of obtaining my Doctorate in Biochemistry. I would also like to thank Dr. Estela Arrese for her kind and generous advice. Both Dr. Soulages and Dr. Arrese have made a tremendous impact on me personally and professionally. I would like to thank all the members of my committee: Dr. Chang-An Yu, Dr. Andrew Mort, and Dr. Jack Dillwith who have devoted their time reading my dissertation and their patience for my procrastination. Their support and guidance has been invaluable and extremely appreciative. Most importantly, I want to acknowledge my parents: (Dr.) Mrs. Fumie Umezu and (Dr.) Mr. Yasuiki Umezu, for their unwavering support of me throughout my time in the U.S. and for suffering me while I’m doing whatever I want in my life.
    [Show full text]
  • Genomic and Non-Genomic Actions of Glucocorticoids on Adipose Tissue Lipid Metabolism
    International Journal of Molecular Sciences Review Genomic and Non-Genomic Actions of Glucocorticoids on Adipose Tissue Lipid Metabolism Negar Mir 1, Shannon A. Chin 1 , Michael C. Riddell 2 and Jacqueline L. Beaudry 1,* 1 Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada; [email protected] (N.M.); [email protected] (S.A.C.) 2 Faculty of Health, School of Kinesiology and Health Science, York University, Toronto, ON M3J 1P3, Canada; [email protected] * Correspondence: [email protected] Abstract: Glucocorticoids (GCs) are hormones that aid the body under stress by regulating glucose and free fatty acids. GCs maintain energy homeostasis in multiple tissues, including those in the liver and skeletal muscle, white adipose tissue (WAT), and brown adipose tissue (BAT). WAT stores energy as triglycerides, while BAT uses fatty acids for heat generation. The multiple genomic and non-genomic pathways in GC signaling vary with exposure duration, location (adipose tissue depot), and species. Genomic effects occur directly through the cytosolic GC receptor (GR), regulating the expression of proteins related to lipid metabolism, such as ATGL and HSL. Non-genomic effects act through mechanisms often independent of the cytosolic GR and happen shortly after GC exposure. Studying the effects of GCs on adipose tissue breakdown and generation (lipolysis and adipogenesis) leads to insights for treatment of adipose-related diseases, such as obesity, coronary disease, and cancer, but has led to controversy among researchers, largely due to the complexity of the process. This paper reviews the recent literature on the genomic and non-genomic effects of GCs on WAT and Citation: Mir, N.; Chin, S.A.; Riddell, BAT lipolysis and proposes research to address the many gaps in knowledge related to GC activity M.C.; Beaudry, J.L.
    [Show full text]
  • Fatty Acid Synthesis ANSC/NUTR 618 Lipids & Lipid Metabolism Fatty Acid Synthesis I
    Handout 5 Fatty Acid Synthesis ANSC/NUTR 618 Lipids & Lipid Metabolism Fatty Acid Synthesis I. Overall concepts A. Definitions 1. De novo synthesis = synthesis from non-fatty acid precursors a. Carbohydrate precursors (glucose and lactate) 1) De novo fatty acid synthesis uses glucose absorbed from the diet rather than glucose synthesized by the liver. 2) De novo fatty acid synthesis uses lactate derived primarily from glucose metabolism in muscle and red blood cells. b. Amino acid precursors (e.g., alanine, branched-chain amino acids) 1) De novo fatty acid synthesis from amino acids is especially important during times of excess protein intake. 2) Use of amino acids for fatty acid synthesis may result in nitrogen overload (e.g., the Atkins diet). c. Short-chain organic acids (e.g., acetate, butyrate, and propionate) 1) The rumen of ruminants is a major site of short-chain fatty acid synthesis. 2) Only small amounts of acetate circulate in non-ruminants. 2. Lipogenesis = fatty acid or triacylglycerol synthesis a. From preformed fatty acids (from diet or de novo fatty acid synthesis) b. Requires source of carbon (from glucose or lactate) for glycerol backbone 3T3-L1 Preadipocytes at confluence. No lipid 3T3-L1 Adipocytes after 6 days of filling has yet occurred. differentiation. Dark spots are lipid droplets. 1 Handout 5 Fatty Acid Synthesis B. Tissue sites of de novo fatty acid biosynthesis 1. Liver. In birds, fish, humans, and rodents (approx. 50% of fatty acid biosynthesis). 2. Adipose tissue. All livestock species synthesize fatty acids in adipose tissue; rodents synthesize about 50% of their fatty acids in adipose tissue.
    [Show full text]
  • Unbalanced Lipolysis Results in Lipotoxicity and Mitochondrial Damage in Peroxisome-Deficient Pex19 Mutants
    M BoC | ARTICLE Unbalanced lipolysis results in lipotoxicity and mitochondrial damage in peroxisome-deficient Pex19 mutants Margret H. Bülowa,*, Christian Wingena, Deniz Senyilmazb, Dominic Gosejacoba, Mariangela Socialea, Reinhard Bauera, Heike Schulzec, Konrad Sandhoffc, Aurelio A. Telemanb, Michael Hocha,*, and Julia Sellina,* aDepartment of Molecular Developmental Biology, Life & Medical Sciences Institute (LIMES), University of Bonn, 53115 Bonn, Germany; bDivision of Signal Transduction in Cancer and Metabolism, German Cancer Research Center, 69120 Heidelberg, Germany; cDepartment of Membrane Biology & Lipid Biochemistry, Life & Medical Sciences Institute (LIMES), Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn, 53121 Bonn, Germany ABSTRACT Inherited peroxisomal biogenesis disorders (PBDs) are characterized by the ab- Monitoring Editor sence of functional peroxisomes. They are caused by mutations of peroxisomal biogenesis Thomas D. Fox factors encoded by Pex genes, and result in childhood lethality. Owing to the many metabolic Cornell University functions fulfilled by peroxisomes, PBD pathology is complex and incompletely understood. Received: Aug 30, 2017 Besides accumulation of peroxisomal educts (like very-long-chain fatty acids [VLCFAs] or Revised: Dec 11, 2017 branched-chain fatty acids) and lack of products (like bile acids or plasmalogens), many per- Accepted: Dec 13, 2017 oxisomal defects lead to detrimental mitochondrial abnormalities for unknown reasons. We generated Pex19 Drosophila mutants, which recapitulate the hallmarks of PBDs, like absence of peroxisomes, reduced viability, neurodegeneration, mitochondrial abnormalities, and ac- cumulation of VLCFAs. We present a model of hepatocyte nuclear factor 4 (Hnf4)-induced lipotoxicity and accumulation of free fatty acids as the cause for mitochondrial damage in consequence of peroxisome loss in Pex19 mutants. Hyperactive Hnf4 signaling leads to up- regulation of lipase 3 and enzymes for mitochondrial β-oxidation.
    [Show full text]
  • Catecholamine-Induced Lipolysis in Obesity
    International Journal of Obesity (1999) 23, Suppl 1, 10±13 ß 1999 Stockton Press All rights reserved 0307±0565/99 $12.00 http://www.stockton-press.co.uk/ijo Catecholamine-induced lipolysis in obesity Peter Arner1* 1Department of Medicine, Karolinska Institute at Huddinge University Hospital, CME, S-141 86 Huddinge, Sweden Catecholamines are the only hormones with pronounced lipolytic action in man. A number of in vivo and in vitro studies suggest that there is lipolytic resistance to catecholamines in subcutaneous adipose tissue, which is the major fat depot in obese subjects. This is due to multiple alterations in catecholamine signal transduction, involving decreased expression and function of b2-adrenoceptors, increased function of a2-adrenoceptors and decreased ability of cyclic monophosphate (AMP) to stimulate hormone sensitive lipase. A sedentary life-style, which usually characterizes obesity, may contribute to the catecholamine resistance. However, hereditary=genetic factors may also be involved. Recently, decreased expression and function of hormone sensitive lipase has been found in subcutaneous adipocytes of non-obese subjects with heredity for obesity. In addition, polymorphisms in the genes for b2-adrenoceptors, b3-adrenoceptors and hormone sensitive lipase, associate with obesity. On the other hand, catecholamine-induced lipolysis in visceral adipose tissue is increased in obesity due to increased function of b3- adrenoceptors (major ®nding), decreased function of a2-adrenoceptors and increased ability of cyclic AMP to stimulate lipolysis. When the ®ndings in different adipose regions are considered together, it appears that there is a re- distribution of lipolysis and thereby fatty acid mobilization in obesity, favouring the visceral fat depot.
    [Show full text]
  • Increased Lipolysis and Its Consequences On
    Increased Lipolysis and Its Consequences on Gluconeogenesis in Non-insulin-dependent Diabetes Mellitus Nurjahan Nurjhan, Agostino Consoli, and John Gerich Clinical Research Center, Departments ofMedicine and Physiology, University ofPittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261 Abstract version to glucose (2-4). Although - 50% ofthe glycerol that is The present studies were undertaken to determine whether Ii- released into plasma in the postabsorptive state is converted to polysis was increased in non-insulin-dependent diabetes melli- glucose (3-5), glycerol is normally considered a minor gluco- tus (NIDDM) and, if so, to assess the influence of increased neogenic substrate since it accounts for only - 3% of overall glycerol availability on its conversion to glucose and its contri- hepatic glucose output and 10% of overall gluconeogenesis (3, bution to the increased gluconeogenesis found in this condition. 4). After a prolonged fast, however, lipolysis greatly increases For this purpose, we infused nine subjects with NIDDM and 16 and the proportion of glycerol turnover used for gluconeogene- sis also increases so that glycerol can account for up to 60% of age-, weight-matched nondiabetic volunteers with 12-3H1 glu- overall cose and IU-'4C1 glycerol and measured their rates of glucose hepatic glucose output (3). and glycerol appearance in plasma and their rates of glycerol In non-insulin-dependent diabetes mellitus (NIDDM),' incorporation into plasma glucose. The rate of glycerol appear- overall gluconeogenesis is increased (6), and recently enhanced ance, an index of lipolysis, was increased 1.5-fold in NIDDM conversion of both lactate and alanine to glucose has been re- vs. ported (7).
    [Show full text]
  • Lipid Metabolism
    Objectives By the end of lecture the student should: Discuss β oxidation of fatty acids. Illustrate α oxidation of fatty acids. Understand ω oxidation of fatty acids. List sources and fates of active acetate. Oxidation of Fatty Acids 1- β-Oxidation (knoop’s oxidation): . Removal of 2 carbon fragment at a time form Acyl CoA (active FA). .The 2 carbon removed as acetyl CoA. .It occurs in many tissues including liver, kidney & heart FAs to be oxidized must be entered the following 2 steps 2- Transport of acyl 1-Activation of FA COA to mitochondria 1-FA activation Acyl COA synthetase RCOOH RCO~SCOA COASH ATP AMP+P~P 2Pi + E Pyrophosphatase 2- Transport of acyl COA to mitochondria: . Role of carnitine in the transport of LCFA through the inner mithochochondrial membrane Functions of carnitine 1- Transport long chain acyl COA across mitochondrial membrane into the mitochondria so it increases the rate of oxidation of LCFA 2- Transport acetyl-CoA from mitochondria to cytoplasm So it stimulates fatty acid synthesis CoA CoA--SHSH H C α H3C3 α β Cβ Palmitoyl Palmitoyl-CoA -CoA β O ~ S – CoA α H3C α H3C β β CO CO ~ S~ –S CoA – CoA β + + CH3 – CO ~ S –CoA Successive removal of C2 units Acetyl-CoA 8CH3 – CO ~ S – CoA 8CH3 – CO ~ S –Acetyl CoA-CoA Acetyl-CoA Steps of β- Oxidation of FAs Energetics of FA oxidation Palmitic (16C): . β-oxidation of palmitic acid will be repeated 7 cycles producing 8 molecules of acetyl COA . In each cycle FADH2 and NADH+H+ is produced & transported to respiratory chain FADH2 ------------------ 2 ATP NADH+H+ ------------- 3 ATP So 7 cycles 5X7=35 ATP .
    [Show full text]