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Intestinal Cytoplasmic Lipid Droplets, Associated Proteins, and the Regulation of Dietary Fat Absorption Theresa M

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Intestinal Cytoplasmic Lipid Droplets, Associated Proteins, and the Regulation of Dietary Fat Absorption Theresa M Purdue University Purdue e-Pubs Open Access Dissertations Theses and Dissertations 8-2016 Intestinal cytoplasmic lipid droplets, associated proteins, and the regulation of dietary fat absorption Theresa M. D'Aquila Purdue University Follow this and additional works at: https://docs.lib.purdue.edu/open_access_dissertations Part of the Biochemistry Commons, Cell Biology Commons, Molecular Biology Commons, Nutrition Commons, and the Physiology Commons Recommended Citation D'Aquila, Theresa M., "Intestinal cytoplasmic lipid droplets, associated proteins, and the regulation of dietary fat absorption" (2016). Open Access Dissertations. 747. https://docs.lib.purdue.edu/open_access_dissertations/747 This document has been made available through Purdue e-Pubs, a service of the Purdue University Libraries. Please contact [email protected] for additional information. Graduate School Form 30 Updated ¡ ¢¡£ ¢¡¤ ¥ PURDUE UNIVERSITY GRADUATE SCHOOL Thesis/Dissertation Acceptance This is to certify that the thesis/dissertation prepared By Theresa Marie D'Aquila Entitled INTESTINAL CYTOPLASMIC LIPID DROPLETS, ASSOCIATED PROTEINS, AND THE ABSORPTION OF DIETARY FAT. For the degree of Doctor of Philosophy Is approved by the final examining committee: Kimberly K. Buhman Chair Jon A. Story Kee- Hong Kim Nana A. Gletsu-Miller To the best of my knowledge and as understood by the student in the Thesis/Dissertation Agreement, Publication Delay, and Certification Disclaimer (Graduate School Form 32), this thesis/dissertation adheres to the provisions of Purdue University’s “Policy of Integrity in Research” and the use of copyright material. Approved by Major Professor(s): Kimberly K. Buhman Approved by: Connie M. Weaver 7/20/2016 Head of the Departmental Graduate Program Date INTESTINAL CYTOPLASMIC LIPID DROPLETS, ASSOCIATED PROTEINS, AND THE REGULATION OF DIETARY FAT ABSORPTION A Dissertation Submitted to the Faculty of Purdue University by Theresa M D’Aquila In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy August 2016 Purdue University West Lafayette, Indiana ii For my parents, brother, and my adventure buddy iii ACKNOWLEDGEMENTS This dissertation would not have been possible without the help, guidance, and encouragement of advisors, friends, and my family. First and foremost, I would like to express my sincerest gratitude to my advisor Dr. Kim Buhman. Her guidance and support helped me develop into the scientist that I am today. Thank you for always being there ready to listen, give advice, and bullshit science with me. I would also like to thank my academic advisory committee, Dr. Jon Story, Dr. Kee Hong Kim, and Dr. Nana Gletsu-Miller. Your knowledge, advice, and encouragement have been invaluable through this process. I would also like to thank the current and former lab members of the Buhman lab including, Amy Hung, Alicia Carreiro, Lenna Peterson and Dr. Aki Uchida. I’m grateful for your help, advice, and some good laughs. Lastly, I would like to thank my climbing buddies, particularly Bryce Heckaman. Nothing like beers around a campfire after a hard day of climbing to keep everything in perspective. iv TABLE OF CONTENTS Page LIST OF TABLES .............................................................................................................. x LIST OF FIGURES ........................................................................................................... xi LIST OF ABBREVIATIONS .......................................................................................... xiii ABSTRACT ...................................................................................................................... xv CHAPTER 1. INTRODUCTION .................................................................................... 1 1.1 Dietary fat, health, and disease .................................................................................. 1 1.1.1 Dietary fat structure and composition .............................................................. 1 1.1.2 Dietary fat, fat soluble vitamins, and essential fatty acids .............................. 2 1.1.3 Dietary fat and risk for disease ........................................................................ 2 1.2 Intestinal metabolism of dietary fat ........................................................................... 4 1.2.1 Digestion and uptake of dietary fat .................................................................. 4 1.2.2 Fatty acid uptake and metabolism ................................................................... 5 1.2.3 Fatty acid re-esterification ............................................................................... 7 1.2.4 Triacylglycerol synthesis ............................................................................... 10 1.2.5 Chylomicron synthesis and secretion ............................................................ 10 1.2.6 Cytoplasmic lipid droplets and triacylglycerol storage ................................. 12 1.3 Cytoplasmic lipid droplet metabolism .................................................................... 13 1.3.1 General knowledge of CLD metabolism ....................................................... 13 1.3.1.1 Physiological conditions promoting CLDs ............................................... 13 1.3.1.2 CLD composition ..................................................................................... 13 1.3.1.2.1 Neutral and phospholipid composition ............................................... 14 1.3.1.2.2 General CLD associated proteins ........................................................ 14 1.3.1.3 CLD connection with organelles .............................................................. 16 v Page 1.3.1.4 Roles of CLDs .......................................................................................... 16 1.3.1.5 CLD synthesis ........................................................................................... 18 1.3.1.6 CLD catabolism ........................................................................................ 20 1.3.1.6.1 Adipose Triglyceride Lipase ............................................................... 20 1.3.1.6.2 Comparative Gene Identification- 58 .................................................. 21 1.3.1.6.3 Hormone Sensitive Lipase .................................................................. 21 1.3.1.6.4 Monoacylglycerol Lipase .................................................................... 22 1.3.1.6.5 Putative methods of CLD catabolism .................................................. 22 1.3.2 CLD protein in enterocytes ............................................................................ 24 1.3.2.1 Physiological conditions promoting CLDs in enterocytes ....................... 24 1.3.2.2 CLD composition ..................................................................................... 25 1.3.2.2.1 Neutral and phospholipid composition ............................................... 25 1.3.2.2.2 Perilipins.............................................................................................. 26 1.3.2.3 CLDs may serve multiple roles in the enterocyte ..................................... 27 1.3.2.4 CLD synthesis ........................................................................................... 28 1.3.2.5 CLD catabolism ........................................................................................ 29 1.3.2.5.1 Adipose Triglyceride Lipase ............................................................... 29 1.3.2.5.2 Comparative Gene Identification-58 ................................................... 30 1.3.2.5.3 Hormone Sensitive Lipase .................................................................. 30 1.3.2.5.4 Monoacylglycerol Lipase .................................................................... 31 1.3.2.5.5 Putative methods of CLD catabolism .................................................. 32 1.3.2.5.6 Autophagy ........................................................................................... 33 1.4 Methods for identifying CLD associated proteins .................................................. 33 1.4.1 Introduction to identifying CLD associated proteins ..................................... 34 1.4.2 Isolation of CLD associated proteins ............................................................. 34 1.4.3 Proteomics methods ....................................................................................... 35 1.4.3.1 Targeted approach .................................................................................... 35 1.4.3.2 Global approach ........................................................................................ 35 1.4.4 Confirmation of CLD associated proteins by imaging .................................. 36 vi Page 1.5 Recent discoveries and new mysteries of CLD associated proteins ....................... 37 1.5.1 General observation of newly identified CLD associated proteins ............... 37 1.5.2 Newly identified CLD associated proteins in enterocytes ............................. 37 1.6 Effects of obesity on dietary fat absorption ............................................................ 38 1.6.1 Whole animal/ physiological consequences .................................................. 38 1.6.2 Enterocyte specific consequences .................................................................. 39 1.7 Conclusion ..............................................................................................................
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