Research Collection Doctoral Thesis Fatty acid oxidation and ketogenesis in energy homeostasis Author(s): Fedele, Shahana Publication Date: 2018 Permanent Link: https://doi.org/10.3929/ethz-b-000266357 Rights / License: In Copyright - Non-Commercial Use Permitted This page was generated automatically upon download from the ETH Zurich Research Collection. For more information please consult the Terms of use. ETH Library DISS. ETH NO. 24833 Fatty acid oxidation and ketogenesis in energy homeostasis A thesis submitted to attain the degree of DOCTOR OF SCIENCES of ETH ZURICH (Dr. sc. ETH Zurich) presented by SHAHANA FEDELE Laurea Specialistica in Biologia applicata alle scienze della nutrizione, Università degli Studi di Milano (Milan, Italy) born on 01.04.1988 citizen of Italy and Australia Prof. Dr. Wolfgang Langhans, examiner Prof. Dr. Barry Levin, co-examiner Prof. Dr. Thomas Lutz, co-examiner Dr. Abdelhak Mansouri, co-examiner 2018 Acknowledgements Acknowledgements I have been staring at this white page for a while now and I am still not sure where to start, because without all the people who may be reading this section and without many other who are not reading it, I would not be here compiling this thesis. Therefore, this is my first sentence: THANK YOU ALL. The biggest thank you goes to you Wolfgang, not only for welcoming me in your lab, but foremost for turning me into a thinking scientist. I have always felt incredibly lucky in experiencing the perfect balance between supervision and freedom, the former guided me, the latter pushed me into that constant vortex of questioning, analyzing and thinking. I do not think I could, at the end of this journey in your lab, ask to feel any more enriched than I do. Abdelhak, I do not think I ever felt as much part of a team as in these final months with you, actually, this holds true for the past (nearly) four years. Your constant support and patience in listening to all my ideas has been priceless. Barry, Thomas, I am grateful for the meetings and discussions we had throughout the years, they certainly have further pushed me to develop critical thinking skills. I always had the impression you were actually interested in my research, and that, I always treasured. I am not sure I should thank you for the additional workload you gave me in this last year (), but I have never felt as excited about research as with this last project: thank you. There was this saying in our lab: “at the end of your first year of PhD at some point you will be lost, you go to Urs and then you’ll know what to do and where to head”. It couldn’t be any truer. Thank you for “saving” me when I was lost, Urs. A special thank you to you Myrtha, not only half of my projects would not have been possible without your amazing surgery skills, but, mostly, you set my standards for precision and organization. Jp, Deepti, Rosi, Sharon (in no particular order) I will not pinpoint specific aspects for which I am thankful to you guys, I feel it would be reductive. You have just simply been everything one could wish for: not only colleagues, you have been friends, mentors and my lab family. You all are great minds, but mostly, you have great hearts. (ah yes, Jp&Rosi: thank you for leaving me your coffee machine when you left!). Angelica, it has been short, but it was great having you here! Melanie, Marie, Nino, Nadja, Shin 1 Acknowledgements and the rest of the former and present Langhans team: it has been a real pleasure. To Sabrina and Valentina: you were amazing students. “Switching corridors”, a big thank you to all present and former “Wolfrums”, but it would be an incomplete section of acknowledgments without specifically thanking three people. Salvo: you are an incredible scientist and I was so lucky to be able to learn even just a little bit from you: grazie! Gerald, I am sure you don’t need to read these lines to know how much I treasure all our scientific - and non – conversations, you have been part of my lab (and extended) family. And finally, one of the most heartfelt ‘thank you’ among them all, to you, Bernd, steady nucleus of my life while I bounce around as a crazy electron. A thank you also to all the rest of SLA team, no one excluded. Elena, Arianna and Mara: you have been my non-lab family throughout these years here in Zurich, life without you would have been much sadder. A thank you also goes to all my friends spread throughout the world, and to all the people I met and that somehow left me something, made me a better person, inspired me, guided me, taught me. In this respect a special thank you goes to my former mentor, Dr. Fernando Viteri and to “the boss” Dr. Cinzia Menchise. Two additional thank you: one goes to a very old man I once met on a tram in Milan who gave me his secret for longevity: “never get upset or angry, no matter what happens, never get upset” (some of the meaning is lost in translation). The second one to a woman I recently met who made me realize the importance of the “taking and giving back” cycle: “I have been helped so much in the past, now it’s my time to help someone else”, that is what she said. And here comes my last thank you, to my actual family. I will never be able to express in words how thankful I am; I just would not be here without you. A thank you to my mother, the most elegant and loving woman I ever met, she had this power of always knowing what was best for me before I even did. To my dad and my brother, I know you do not like “wishy-washy” stuff, but you are the two people I think most highly of in the whole planet. …you may also be relieved in knowing that I think I am finally done studying! 2 Table of contents Table of contents Aknowledgments 1 List of abbreviations 5 Summary 8 Riassunto 10 CHAPTER 1: General introduction 13 1. Obesity and overweight 13 1.1 The control of energy intake 14 1.1.1 The hypothalamic circuitry 14 1.1.2 The hindbrain circuitry 15 1.1.3 The mesolimbic circuitry 16 2. Gut-brain axis 17 2.1 Parasympathetic innervation 18 2.2 Sympathetic innervation 18 2.3 Enteric nervous system (ENS) 18 3. Peripheral signals modulating food intake 19 3.1 Gastrointestinal peptides 19 3.2 Adiposity signals 20 4. The endocannabinoid and endocannabinoid-like signaling 21 4.1 Oleoylethanolamide 22 5. Intestinal fatty acid oxidation and ketogenesis 23 6. Central nervous system (CNS) fatty acid oxidation and ketogenesis 24 7. The aims of the thesis 26 3 Table of contents CHAPTER 2: Oleoylethanolamide-induced anorexia in rats is 35 associated with locomotor impairment CHAPTER3: Expression of a mutated form of carnitine 61 palmitoyltransferase-1A in astrocytes CHAPTER 4: Knockdown of HMGCS2 in the basomedial hypothalamus 93 affects energy homeostasis in rats CHAPTER 5: General discussion 125 1. Overview of the findings 126 2. Oleoylethanolamide – connecting the dots 128 3. Ketone bodies: versatile effectors 132 4. Fatty acids in the brain: friends or foes? 135 5. At last: food for thought 137 Curriculum Vitae 145 4 List of abbreviations List of abbreviations 2-AG: 2-arachidonoylglycerol 2-DG: 2-deoxy-D-glucose α-MSH= alpha- melanocyte-stimulating hormone AAV= adeno-associate virus AcAc= acetoacetate ACC= acetyl-CoA carboxylase ACSA2= astrocyte cell surface antigen-2 ACSF= artificial cerebrospinal fluid AEA= N-arachidonoylethanolamine = Anandamide AgRP= agouti-related peptide AMPk= AMP-activated protein kinase Ant= antimycin AP= area postrema Arc= arcuate nucleus BBB= brain blood barrier BHB= β-hydroxybutyrate BPTES= Bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl)ethyl sulphide C8= octanoic acid CART= cocaine and amphetamine related transcript Cat= catalase CB= cannabinoid Receptor CCK= cholecystokinin CD36= cluster differentiation 36 CGX= celiac-mesenteric-superior ganglionectomy CMV= cytomegalovirus CNS= central nervous system CPT= carnitine palmitoyltransferase CPTmt= carnitine palmitoyltransferase mutated DA= dopamine DGAT-1= diacylglycerol acyltransferase-1 DMH= dorsal medial hypothalamus DMV= dorsal motor nucleus of the vagus nerve DRG= dorsal root ganglia eCBs= endocannabinoids EC= endocannabinoid system ECAR= extracellular acidification rate EE= energy expenditure EEC= enteroendocrine cells Eno2= neuron specific enolase ENS= enteric nervous system ERT2= estrogen receptor variant Eto= etomoxir FA= fatty acids FABP= fatty acid binding protein FAO= fatty acid oxidation FAS= fatty acid synthesis FATP= fatty acid transport protein FBS= fetal bovine serum 5 List of abbreviations FCCP= carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone GABA= γ-aminobutyric acid GAD= glutamate decarboxylase GFAP= glial fibrillary acidic protein GFP= green fluorescent protein GLP-1= glucagon-like peptide-1 GLUT1= glucose transporter 1 GPR= G-protein coupled receptor GPX4= glutathione peroxidase 4 GS= glutamine synthetase GSS= glutathione synthetase HEK= human embrionic kidney cells HFD= high fat diet HK1= hesokinase1 HMGCS2= 3-Hydroxy-3-Methylglutaryl-CoA Synthase 2 HRP= horseradish peroxidase Icv= intracerebroventricular ID= inner diameter IP= intraperitoneal IpGTT= intraperitoneal glucose tolerance test KATP= ATP sensitive potassium channels KB= ketone bodies Kd= knockdown LCAD= long chain acyl-coA dehydrogenase LCFA= long chain fatty acids LDH= lactate dehydrogenase LFD= low fat diet LH= lateral hypothalamus LV= lentivirus MCFA= medium-chain fatty acids MCH= melanin-concentrating hormone MCR= melanocortin receptor MCT= monocarboxylate transporter NAc= nucleus accumbens nAChR= nicotinic acetylcholine receptors NAEs= N-Acetylamides NE= norepinephrine NEFA= non-esterified