1
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Hammoudeh N, Soukkarieh C, Murphy DJ, Hanano A. Mammalian lipid droplets: structural, pathological, immunological and anti-toxicological roles. Prog Lipid Res 2023; 91:101233. [PMID: 37156444 DOI: 10.1016/j.plipres.2023.101233] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 04/30/2023] [Accepted: 05/05/2023] [Indexed: 05/10/2023]
Abstract
Mammalian lipid droplets (LDs) are specialized cytosolic organelles consisting of a neutral lipid core surrounded by a membrane made up of a phospholipid monolayer and a specific population of proteins that varies according to the location and function of each LD. Over the past decade, there have been significant advances in the understanding of LD biogenesis and functions. LDs are now recognized as dynamic organelles that participate in many aspects of cellular homeostasis plus other vital functions. LD biogenesis is a complex, highly-regulated process with assembly occurring on the endoplasmic reticulum although aspects of the underpinning molecular mechanisms remain elusive. For example, it is unclear how many enzymes participate in the biosynthesis of the neutral lipid components of LDs and how this process is coordinated in response to different metabolic cues to promote or suppress LD formation and turnover. In addition to enzymes involved in the biosynthesis of neutral lipids, various scaffolding proteins play roles in coordinating LD formation. Despite their lack of ultrastructural diversity, LDs in different mammalian cell types are involved in a wide range of biological functions. These include roles in membrane homeostasis, regulation of hypoxia, neoplastic inflammatory responses, cellular oxidative status, lipid peroxidation, and protection against potentially toxic intracellular fatty acids and lipophilic xenobiotics. Herein, the roles of mammalian LDs and their associated proteins are reviewed with a particular focus on their roles in pathological, immunological and anti-toxicological processes.
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Affiliation(s)
- Nour Hammoudeh
- Department of Animal Biology, Faculty of Sciences, University of Damascus, Damascus, Syria
| | - Chadi Soukkarieh
- Department of Animal Biology, Faculty of Sciences, University of Damascus, Damascus, Syria
| | - Denis J Murphy
- School of Applied Sciences, University of South Wales, Pontypridd, CF37 1DL, Wales, United Kingdom..
| | - Abdulsamie Hanano
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), P.O. Box 6091, Damascus, Syria..
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2
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Chen J, Li S, Ma D, Li L, Zhuang W, Chen M. A lipid droplet-specific fluorescence probe for atherosclerotic plaque imaging. Analyst 2022; 147:3081-3086. [PMID: 35678714 DOI: 10.1039/d1an01937f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The dysregulation of lipid droplets (LDs) is closely related to certain metabolic diseases, while the role of LDs during pathological processes remains mysterious. It would be of great value to monitor the dynamic changes of LDs in a visible way so as to study their biological functions. In this study, we report a LD-specific fluorescence probe TBI for precise LD-targeting imaging in cells and atherosclerotic tissues. TBI exhibited great biocompatibility, remarkable oil-enhanced fluorescence emission, good photostability and impressive intracellular and tissular LD-specific imaging performance. Importantly, TBI could efficiently stain the LDs at a low concentration of 50 nM, and the motion tracking of LDs could be observed via fluorescence imaging. Moreover, TBI could efficiently light up the LD distribution in mouse atherosclerotic plaques with high resolution, which revealed the ultra-structure of atherosclerotic plaques. In conclusion, these results imply that TBI could be a potential tool for investigating the physiological and pathological role of LDs.
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Affiliation(s)
- Jingruo Chen
- Laboratory of Heart Valve Disease, West China Hospital, Sichuan University, 37 Guoxue Road, Chengdu 610041, PR China.
| | - Shufen Li
- Laboratory of Heart Valve Disease, West China Hospital, Sichuan University, 37 Guoxue Road, Chengdu 610041, PR China.
| | - Di Ma
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu 610041, PR China
| | - Lilan Li
- Laboratory of Heart Valve Disease, West China Hospital, Sichuan University, 37 Guoxue Road, Chengdu 610041, PR China.
| | - Weihua Zhuang
- Laboratory of Heart Valve Disease, West China Hospital, Sichuan University, 37 Guoxue Road, Chengdu 610041, PR China.
| | - Mao Chen
- Laboratory of Heart Valve Disease, West China Hospital, Sichuan University, 37 Guoxue Road, Chengdu 610041, PR China. .,Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu 610041, PR China.,Department of Cardiology, West China Hospital, Sichuan University, 37 Guoxue Road, Chengdu 610041, PR China
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3
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Naveed A, Naveed MA, Akram L, Sharif M, Kang MI, Park SI. Rotavirus exploits SREBP pathway for hyper lipid biogenesis during replication. J Gen Virol 2022; 103. [PMID: 35594141 DOI: 10.1099/jgv.0.001757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Species A rotavirus (RVA) is one of the pathogens causing severe acute gastroenteritis in young children and animals worldwide. RVA replicates and assembles its immature particle within electron dense compartments known as viroplasm. Despite the importance of lipid droplet (LD) formation in the RVA viroplasm, the upstream molecules modulating LD formation have remained elusive. Here, we demonstrate that RVA infection reprogrammes sterol regulatory element binding proteins (SREBPs)-dependent lipogenic pathways in virus-infected cells. Interestingly, silencing of SREBPs significantly reduced RVA protein synthesis, genome replication and progeny virus production. Moreover, knockout of SREBP-1c gene conferred resistance to RVA-induced diarrhoea, reduction of RVA replication, and mitigation of small intestinal pathology in mice. This study identifies SREBPs-mediated lipogenic reprogramming in RVA-infected host cells for facilitating virus replication and SREBPs as a potential target for developing therapeutics against RVA infection.
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Affiliation(s)
- Ahsan Naveed
- Laboratory of Veterinary Pathology, College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Republic of Korea
| | | | - Lubna Akram
- District Headquarter Hospital, Pakpattan Sharif 57400, Pakistan
| | - Muhammad Sharif
- Laboratory of Veterinary Pathology, College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Mun-Il Kang
- Laboratory of Veterinary Pathology, College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Sang-Ik Park
- Laboratory of Veterinary Pathology, College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Republic of Korea
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4
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Tsai NC, Hsu TS, Kuo SC, Kao CT, Hung TH, Lin DG, Yeh CS, Chu CC, Lin JS, Lin HH, Ko CY, Chang TH, Su JC, Lin YCJ. Large-scale data analysis for robotic yeast one-hybrid platforms and multi-disciplinary studies using GateMultiplex. BMC Biol 2021; 19:214. [PMID: 34560855 PMCID: PMC8461970 DOI: 10.1186/s12915-021-01140-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 09/03/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Yeast one-hybrid (Y1H) is a common technique for identifying DNA-protein interactions, and robotic platforms have been developed for high-throughput analyses to unravel the gene regulatory networks in many organisms. Use of these high-throughput techniques has led to the generation of increasingly large datasets, and several software packages have been developed to analyze such data. We previously established the currently most efficient Y1H system, meiosis-directed Y1H; however, the available software tools were not designed for processing the additional parameters suggested by meiosis-directed Y1H to avoid false positives and required programming skills for operation. RESULTS We developed a new tool named GateMultiplex with high computing performance using C++. GateMultiplex incorporated a graphical user interface (GUI), which allows the operation without any programming skills. Flexible parameter options were designed for multiple experimental purposes to enable the application of GateMultiplex even beyond Y1H platforms. We further demonstrated the data analysis from other three fields using GateMultiplex, the identification of lead compounds in preclinical cancer drug discovery, the crop line selection in precision agriculture, and the ocean pollution detection from deep-sea fishery. CONCLUSIONS The user-friendly GUI, fast C++ computing speed, flexible parameter setting, and applicability of GateMultiplex facilitate the feasibility of large-scale data analysis in life science fields.
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Affiliation(s)
- Ni-Chiao Tsai
- Department of Life Science and Institute of Plant Biology, College of Life Science, National Taiwan University, Taipei, 10617, Taiwan
| | - Tzu-Shu Hsu
- Department of Pharmacy, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Shang-Che Kuo
- Department of Pharmacy, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
- Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei, 10617, Taiwan
| | - Chung-Ting Kao
- Department of Life Science and Institute of Plant Biology, College of Life Science, National Taiwan University, Taipei, 10617, Taiwan
| | - Tzu-Huan Hung
- Biotechnology Division, Taiwan Agricultural Research Institute, Taichung, 41362, Taiwan
| | - Da-Gin Lin
- Biotechnology Division, Taiwan Agricultural Research Institute, Taichung, 41362, Taiwan
| | - Chung-Shu Yeh
- Genomics Research Center, Academia Sinica, Taipei, 11529, Taiwan
| | - Chia-Chen Chu
- Department of Life Science and Institute of Plant Biology, College of Life Science, National Taiwan University, Taipei, 10617, Taiwan
| | - Jeng-Shane Lin
- Department of Life Sciences, National Chung Hsing University, Taichung, 40227, Taiwan
| | - Hsin-Hung Lin
- Department of Horticulture and Biotechnology, Chinese Culture University, Taipei, 11114, Taiwan
| | - Chia-Ying Ko
- Department of Life Sciences and Institute of Fisheries Science, National Taiwan University, Taipei, 10617, Taiwan
| | - Tien-Hsien Chang
- Genomics Research Center, Academia Sinica, Taipei, 11529, Taiwan.
| | - Jung-Chen Su
- Department of Pharmacy, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan.
| | - Ying-Chung Jimmy Lin
- Department of Life Science and Institute of Plant Biology, College of Life Science, National Taiwan University, Taipei, 10617, Taiwan.
- Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei, 10617, Taiwan.
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5
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Auclair N, Patey N, Melbouci L, Ou Y, Magri-Tomaz L, Sané A, Garofalo C, Levy E, St-Pierre DH. Acylated Ghrelin and The Regulation of Lipid Metabolism in The Intestine. Sci Rep 2019; 9:17975. [PMID: 31784591 PMCID: PMC6884495 DOI: 10.1038/s41598-019-54265-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 11/05/2019] [Indexed: 01/01/2023] Open
Abstract
Acylated ghrelin (AG) is a gastrointestinal (GI) peptide mainly secreted by the stomach that promotes cytosolic lipid droplets (CLD) hypertrophy in adipose tissues and liver. However, the role of AG in the regulation of lipid metabolism in the intestine remains unexplored. This study aimed at determining whether AG influences CLD production and chylomicron (CM) secretion in the intestine. The effects of AG and oleic acid on CLD accumulation and CM secretion were first investigated in cultured Caco-2/15 enterocytes. Intestinal lipid metabolism was also studied in Syrian Golden Hamsters submitted to conventional (CD) or Western (WD) diets for 8 weeks and continuously administered with AG or physiological saline for the ultimate 2 weeks. In cultured Caco-2/15 enterocytes, CLD accumulation influenced CM secretion while AG reduced fatty acid uptake. In WD hamsters, continuous AG treatment amplified chylomicron output while reducing postprandial CLD accumulation in the intestine. The present study supports the intimate relationship between CLD accumulation and CM secretion in the intestine and it underlines the importance of further characterizing the mechanisms through which AG exerts its effects on lipid metabolism in the intestine.
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Affiliation(s)
- N Auclair
- CHU Sainte-Justine Research Center, University of Montreal, Montreal, H3T 1C5, Quebec, Canada.,Department of Exercise Science, University of Quebec in Montreal (UQAM), Montreal, H2X 1Y4, Quebec, Canada
| | - N Patey
- CHU Sainte-Justine Research Center, University of Montreal, Montreal, H3T 1C5, Quebec, Canada
| | - L Melbouci
- CHU Sainte-Justine Research Center, University of Montreal, Montreal, H3T 1C5, Quebec, Canada.,Department of Exercise Science, University of Quebec in Montreal (UQAM), Montreal, H2X 1Y4, Quebec, Canada
| | - Y Ou
- Department of Exercise Science, University of Quebec in Montreal (UQAM), Montreal, H2X 1Y4, Quebec, Canada
| | - L Magri-Tomaz
- Department of Exercise Science, University of Quebec in Montreal (UQAM), Montreal, H2X 1Y4, Quebec, Canada
| | - A Sané
- CHU Sainte-Justine Research Center, University of Montreal, Montreal, H3T 1C5, Quebec, Canada
| | - C Garofalo
- CHU Sainte-Justine Research Center, University of Montreal, Montreal, H3T 1C5, Quebec, Canada
| | - E Levy
- CHU Sainte-Justine Research Center, University of Montreal, Montreal, H3T 1C5, Quebec, Canada.,Department of Nutrition, University of Montreal, Montreal, H3T 1A8, Quebec, Canada.,Institute of Nutrition and Functional Foods (INAF), Laval University, Quebec, G1V 0A6, Quebec, Canada
| | - D H St-Pierre
- CHU Sainte-Justine Research Center, University of Montreal, Montreal, H3T 1C5, Quebec, Canada. .,Department of Nutrition, University of Montreal, Montreal, H3T 1A8, Quebec, Canada. .,Department of Exercise Science, University of Quebec in Montreal (UQAM), Montreal, H2X 1Y4, Quebec, Canada. .,Institute of Nutrition and Functional Foods (INAF), Laval University, Quebec, G1V 0A6, Quebec, Canada.
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6
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Sharma G, Tripathi SK, Das S. lncRNA HULC facilitates efficient loading of HCV-core protein onto lipid droplets and subsequent virus-particle release. Cell Microbiol 2019; 21:e13086. [PMID: 31290220 DOI: 10.1111/cmi.13086] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 06/29/2019] [Accepted: 07/07/2019] [Indexed: 12/11/2022]
Abstract
The cellular lipid pool plays a central role in hepatitis C virus (HCV) life cycle, from establishing infection to virus propagation. Here, we show that a liver abundant long noncoding RNA, highly upregulated in liver carcinoma (HULC), is upregulated during HCV infection and manipulates the lipid pool to favour virus life cycle. Interestingly, HULC was found to be crucial for the increase in number of lipid droplets in infected cells. This effect was attributed to the role of HULC in lipid biogenesis. Further, we demonstrated that HULC knockdown decreases the association of HCV-core protein with lipid droplets. This exhibited a direct consequence on the release of HCV particles. The role of HULC in HCV-particle release was further substantiated by additional knockdown and mutation experiments. Additionally, we found that increased level of HULC in HCV-infected cells was a result of Retinoid X Receptor Alpha (RXRA)-mediated transcription, which seemed to be aided by HCV-core protein. Taken together, the results identify a distinct role of long noncoding RNA HULC in lipid dynamics during HCV infection, which provides new insights into the complex process of HCV propagation and pathogenesis.
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Affiliation(s)
- Geetika Sharma
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Sachin Kumar Tripathi
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Saumitra Das
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.,National Institute of Biomedical Genomics, Kalyani, India
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7
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Tsui L, Wang IJ. Analysis and Quantification of Oxidized Low-Density Lipoprotein-Induced Lipid Droplets in Macrophages Through High-Content Screening: Application for Antiatherogenic Drugs Discovery. Assay Drug Dev Technol 2019; 17:223-230. [PMID: 31149834 DOI: 10.1089/adt.2019.930] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Leo Tsui
- School of Pharmacy and Medical Technology, Putian University, Fujian, China
| | - I-Jong Wang
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Republic of China
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8
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Niu J, Liu Y, Wang W, Lin W. Novel two-photon fluorescent probe with high fluorescence quantum yields for tracking lipid droplets in biological systems. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 216:35-44. [PMID: 30877892 DOI: 10.1016/j.saa.2019.02.106] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 02/20/2019] [Accepted: 02/25/2019] [Indexed: 06/09/2023]
Abstract
Lipid droplets (LDs) played an important role in storing neutral lipids process. In this work, we developed a series of fluorescent dyes PIE1-PIE4 with high fluorescence quantum yields based on a single phenanthrenequinone imidazole fluorophore core. Among these compounds, we introduced diethyl aniline group on the phenanthrenequinone imidazole core to provide the compound PIE1. It is firstly found that PIE1 could real-color image and track lipid droplets (LDs) in living cells. However, we modified nitrile, imidazole and methyl group on the same fluorophore core to afford three dyes PIE2, PIE3 and PIE4, respectively. Although PIE2, PIE3 and PIE4 possessed high fluorescence quantum yields in various organic solvents, they could not real-color image and track LDs in living cells.
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Affiliation(s)
- Jie Niu
- Institute of Fluorescent Probes for Biological Imaging, School of Materials Science and Engineering, School of Chemistry and Chemical Engineering, University of Jinan, Shandong 250022, PR China
| | - Yong Liu
- Institute of Fluorescent Probes for Biological Imaging, School of Materials Science and Engineering, School of Chemistry and Chemical Engineering, University of Jinan, Shandong 250022, PR China
| | - Weishan Wang
- Institute of Fluorescent Probes for Biological Imaging, School of Materials Science and Engineering, School of Chemistry and Chemical Engineering, University of Jinan, Shandong 250022, PR China
| | - Weiying Lin
- Institute of Fluorescent Probes for Biological Imaging, School of Materials Science and Engineering, School of Chemistry and Chemical Engineering, University of Jinan, Shandong 250022, PR China.
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9
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Exner T, Beretta CA, Gao Q, Afting C, Romero-Brey I, Bartenschlager R, Fehring L, Poppelreuther M, Füllekrug J. Lipid droplet quantification based on iterative image processing. J Lipid Res 2019; 60:1333-1344. [PMID: 30926625 DOI: 10.1194/jlr.d092841] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 03/28/2019] [Indexed: 12/15/2022] Open
Abstract
Lipid droplets (LDs) are ubiquitous and highly dynamic subcellular organelles required for the storage of neutral lipids. LD number and size distribution are key parameters affected not only by nutrient supply but also by lipotoxic stress and metabolic regulation. Current methods for LD quantification lack general applicability and are either based on time consuming manual evaluation or show limitations if LDs are high in numbers or closely clustered. Here, we present an ImageJ-based approach for the detection and quantification of LDs stained by neutral lipid dyes in images acquired by conventional wide-field fluorescence microscopy. The method features an adjustable preprocessing procedure that resolves LD clusters. LD identification is based on their circular edges and central fluorescence intensity maxima. Adaptation to different cell types is mediated by a set of interactive parameters. Validation was done for three different cell lines using manual evaluation of LD numbers and volume measurement by 3D rendering of confocal datasets. In an application example, we show that overexpression of the acyl-CoA synthetase, FATP4/ACSVL5, in oleate-treated COS7 cells increased the size of LDs but not their number.
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Affiliation(s)
- Tarik Exner
- Molecular Cell Biology Laboratory Internal Medicine IV, Heidelberg University, Heidelberg, Germany
| | - Carlo A Beretta
- CellNetworks Math-Clinic Core Facility, BioQuant Heidelberg University, Heidelberg, Germany
| | - Qi Gao
- CellNetworks Math-Clinic Core Facility, BioQuant Heidelberg University, Heidelberg, Germany
| | - Cassian Afting
- Molecular Cell Biology Laboratory Internal Medicine IV, Heidelberg University, Heidelberg, Germany
| | - Inés Romero-Brey
- Department of Infectious Diseases, Molecular Virology Heidelberg University, Heidelberg, Germany
| | - Ralf Bartenschlager
- Department of Infectious Diseases, Molecular Virology Heidelberg University, Heidelberg, Germany.,Department of Virus-Associated Carcinogenesis, German Cancer Research Center, Heidelberg, Germany
| | - Leonard Fehring
- Molecular Cell Biology Laboratory Internal Medicine IV, Heidelberg University, Heidelberg, Germany
| | - Margarete Poppelreuther
- Molecular Cell Biology Laboratory Internal Medicine IV, Heidelberg University, Heidelberg, Germany
| | - Joachim Füllekrug
- Molecular Cell Biology Laboratory Internal Medicine IV, Heidelberg University, Heidelberg, Germany
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10
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Argov-Argaman N. Symposium review: Milk fat globule size: Practical implications and metabolic regulation. J Dairy Sci 2019; 102:2783-2795. [PMID: 30639008 DOI: 10.3168/jds.2018-15240] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 11/12/2018] [Indexed: 12/11/2022]
Abstract
Milk fat globule (MFG) size ranges over 3 orders of magnitude, from less than 200 nm to over 15 µm. The significance of MFG size derives from its tight association with its lipidome and proteome. More specifically, small MFG have relatively higher content of membrane compared with large globules, and this membrane exerts diverse positive health effects, as reported in human and animal studies. In addition, MFG size has industrial significance, as it affects the physicochemical and sensory characteristics of dairy products. Studies on the size regulation of MFG are scarce, mainly because various confounders indirectly affect MFG size. Because MFG size is determined before and during its secretion from mammary epithelial cells, studies on the size regulation of its precursors, the intracellular lipid droplets (LD), have been used as a proxy for understanding the mechanisms controlling MFG size. In this review, we provide evidence for 2 distinct mechanisms regulating LD size in mammary epithelial cells: co-regulation of fat content and triglyceride-synthesis capacity of the cells, and fusion between LD. The latter is controlled by the membrane's polar lipid composition and involves mitochondrial enzymes. Accordingly, this review also discusses MFG size regulation in the in vivo metabolic context, as MFG morphometric features are often modulated under conditions that involve animals' altered energy status.
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Affiliation(s)
- Nurit Argov-Argaman
- Department of Animal Science, the Robert H. Smith Faculty of Agriculture, Food and Environment, the Hebrew University of Jerusalem, Israel, POB 76100.
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11
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Lv X, Liu J, Qin Y, Liu Y, Jin M, Dai J, Chua BT, Yang H, Li P. Identification of gene products that control lipid droplet size in yeast using a high-throughput quantitative image analysis. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:113-127. [PMID: 30414449 DOI: 10.1016/j.bbalip.2018.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 10/14/2018] [Accepted: 11/06/2018] [Indexed: 02/07/2023]
Abstract
Lipid droplets (LDs) are important organelles involved in energy storage and expenditure. LD dynamics has been investigated using genome-wide image screening methods in yeast and other model organisms. For most studies, genes were identified using two-dimensional images with LD enlargement as readout. Due to imaging limitation, reduction of LD size is seldom explored. Here, we aim to set up a screen that specifically utilizes reduced LD size as the readout. To achieve this, a novel yeast screen is set up to quantitatively and systematically identify genes that regulate LD size through a three-dimensional imaging-based approach. Cidea which promotes LD fusion and growth in mammalian cells was overexpressed in a yeast knockout library to induce large LD formation. Next, an automated, high-throughput image analysis method that monitors LD size was utilized. With this screen, we identified twelve genes that reduced LD size when deleted. The effects of eight of these genes on LD size were further validated in fld1 null strain background. In addition, six genes were previously identified as LD-regulating genes. To conclude, this methodology represents a promising strategy to screen for players in LD size control in both yeast and mammalian cells to aid in the investigation of LD-associated metabolic diseases.
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Affiliation(s)
- Xuchao Lv
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jiaming Liu
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yiran Qin
- MOE Key Laboratory of Bioinformatics and Centre for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yizhang Liu
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Meijun Jin
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Junbiao Dai
- MOE Key Laboratory of Bioinformatics and Centre for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Boon Tin Chua
- Institute of Metabolism and Integrative Biology, Fudan University, Shanghai 200438, China
| | - Hongyuan Yang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Peng Li
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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12
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Coles CA, Maksimovic J, Wadeson J, Fahri FT, Webster T, Leyton C, McDonagh MB, White JD. Knockdown of a disintegrin A metalloprotease 12 (ADAM12) during adipogenesis reduces cell numbers, delays differentiation, and increases lipid accumulation in 3T3-L1 cells. Mol Biol Cell 2018; 29:1839-1855. [PMID: 29846135 PMCID: PMC6085825 DOI: 10.1091/mbc.e17-07-0471] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Mouse models have shown that a disintegrin A metalloprotease 12 (ADAM12) is implicated during adipogenesis; the molecular pathways are not well understood. Stealth RNA interference was used to knock down ADAM12 in 3T3-L1 cells. Using gene profiling and metabolic enzymatic markers, we have identified signaling pathways ADAM12 impacts upon during proliferation, differentiation, and maturation of adipocytes. ADAM12 reduced cell numbers in proliferating preadipocytes, delayed differentiation of preadipocytes to adipocytes, and increased lipid accumulation in mature adipocytes. The pathway most affected by ADAM12 knockdown was regulation of insulin-like growth factor (IGF) activity by insulin-like growth factor binding proteins (IGFBPs); ADAM12 is known to cleave IGFBP3 and IGFBP5. The IGF/mTOR signaling pathway was down-regulated, supporting a role for ADAM12 in the IGFBP/IGF/mTOR-growth pathway. PPARγ signaling was also down-regulated by ADAM12 knockdown. Gene ontology (GO) analysis revealed that the extracellular matrix was the cellular compartment most impacted. Filtering for matrisome genes, connective tissue growth factor (Ctgf) was up-regulated. CTGF and IGBP3 can interact with PPARγ to hinder its regulation. Increased expression of these molecules could have influenced PPARγ signaling reducing differentiation and an imbalance of lipids. We believe ADAM12 regulates cell proliferation of preadipocytes through IGFBP/IGF/mTOR signaling and delays differentiation through altered PPAR signaling to cause an imbalance of lipids within mature adipocytes.
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Affiliation(s)
- Chantal A Coles
- Murdoch Children's Research Institute, Royal Children's Hospital, Parkville 3052, Australia.,Faculty of Veterinary and Agricultural Science, University of Melbourne, Melbourne 3052, Australia
| | - Jovana Maksimovic
- Murdoch Children's Research Institute, Royal Children's Hospital, Parkville 3052, Australia.,Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne 3052, Australia
| | - Jenny Wadeson
- Discovery Technologies, Department of Environment and Primary -Industries, Victoria Centre for AgriBioscience, La Trobe University, Melbourne 3083, Australia
| | - Fahri T Fahri
- Department of Primary Industries, New South Wales Food Authority, Sydney, New South Wales 2001, Australia
| | - Tracie Webster
- Discovery Technologies, Department of Environment and Primary -Industries, Victoria Centre for AgriBioscience, La Trobe University, Melbourne 3083, Australia
| | - Carolina Leyton
- Discovery Technologies, Department of Environment and Primary -Industries, Victoria Centre for AgriBioscience, La Trobe University, Melbourne 3083, Australia
| | - Matthew B McDonagh
- Discovery Technologies, Department of Environment and Primary -Industries, Victoria Centre for AgriBioscience, La Trobe University, Melbourne 3083, Australia.,Cooperative Animal Research Centre for Sheep Industry Innovation, University of New England, Armidale, New South Wales 2350, Australia
| | - Jason D White
- Murdoch Children's Research Institute, Royal Children's Hospital, Parkville 3052, Australia.,Faculty of Veterinary and Agricultural Science, University of Melbourne, Melbourne 3052, Australia
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13
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Luo WJ, Cheng TY, Wong KI, Fang WH, Liao KM, Hsieh YT, Su KY. Novel therapeutic drug identification and gene correlation for fatty liver disease using high-content screening: Proof of concept. Eur J Pharm Sci 2018; 121:106-117. [PMID: 29800612 DOI: 10.1016/j.ejps.2018.05.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 05/13/2018] [Accepted: 05/18/2018] [Indexed: 02/06/2023]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a problem in obese people caused by increasing intake of high-calorie food such as fructose implicated in the elevated prevalence. It is necessary to identify novel drugs to develop effective therapies. In this study, we combined LOPAC® (The Library of Pharmacologically Active Compounds) and High-Content screening to identify compounds that significantly reduced intracellular lipid droplets (LD) after high fat medium (HFM) treatment. Among 1280 compounds, we identified 239 compounds that reduced LD by >50%. Of these, 17 maintained cell viability. Nine of them were selected for validation using normal primary hepatocytes, of which five compounds showed dose-dependent efficacy. Whole genome transcriptomic network analysis was performed to construct the underlying regulatory network. There were 831 (711 up-regulated and 120 down-regulated genes) and 3480 (2009 up-regulated and 1471 down-regulated genes) genes that showed a significant change (>2-fold; p < 0.05) after 12 and 24 h HFM treatment, respectively. Gene enrichment and pathway analysis showed several immune responses mediated by MIF, IL-17, TLR, and IL-6. These compounds modulate lipogenesis via GSK3β and CREB1, which is followed by an alteration in the expression of several downstream genes related to hepatocellular carcinoma and hepatitis. CREB1 is a core transcription factor and may be a potential therapeutic target for liver disease. In conclusion, this proof of concept provides a strategy for identifying novel drugs for treatment of fatty liver disease as well as elucidates their underlying mechanisms. This research provides opportunity for developing future pharmaceutical therapeutics.
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Affiliation(s)
- Wei-Jia Luo
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ting-Yu Cheng
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Keng-Ieng Wong
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Woei-Horng Fang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Keng-Mao Liao
- Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei, Taiwan
| | - Yun-Ting Hsieh
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Kang-Yi Su
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan; Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei, Taiwan; Center of Genomic Medicine, National Taiwan University, Taipei, Taiwan; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan.
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14
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McDonough PM, Prigozhina NL, Basa RCB, Price JH. Assay of Calcium Transients and Synapses in Rat Hippocampal Neurons by Kinetic Image Cytometry and High-Content Analysis: An In Vitro Model System for Postchemotherapy Cognitive Impairment. Assay Drug Dev Technol 2018; 15:220-236. [PMID: 28723268 DOI: 10.1089/adt.2017.797] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Postchemotherapy cognitive impairment (PCCI) is commonly exhibited by cancer patients treated with a variety of chemotherapeutic agents, including the endocrine disruptor tamoxifen (TAM). The etiology of PCCI is poorly understood. Our goal was to develop high-throughput assay methods to test the effects of chemicals on neuronal function applicable to PCCI. Rat hippocampal neurons (RHNs) were plated in 96- or 384-well dishes and exposed to test compounds (forskolin [FSK], 17β-estradiol [ES]), TAM or fulvestrant [FUL], aka ICI 182,780) for 6-14 days. Kinetic Image Cytometry™ (KIC™) methods were developed to quantify spontaneously occurring intracellular calcium transients representing the activity of the neurons, and high-content analysis (HCA) methods were developed to quantify the expression, colocalization, and puncta formed by synaptic proteins (postsynaptic density protein-95 [PSD-95] and presynaptic protein Synapsin-1 [Syn-1]). As quantified by KIC, FSK increased the occurrence and synchronization of the calcium transients indicating stimulatory effects on RHN activity, whereas TAM had inhibitory effects. As quantified by HCA, FSK also increased PSD-95 puncta and PSD-95:Syn-1 colocalization, whereas ES increased the puncta of both PSD-95 and Syn-1 with little effect on colocalization. The estrogen receptor antagonist FUL also increased PSD-95 puncta. In contrast, TAM reduced Syn-1 and PSD-95:Syn-1 colocalization, consistent with its inhibitory effects on the calcium transients. Thus TAM reduced activity and synapse formation by the RHNs, which may relate to the ability of this agent to cause PCCI. The results illustrate that KIC and HCA can be used to quantify neurotoxic and neuroprotective effects of chemicals in RHNs to investigate mechanisms and potential therapeutics for PCCI.
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Affiliation(s)
| | | | | | - Jeffrey H Price
- 1 Vala Sciences Inc. , San Diego, California.,3 The Scintillon Institute , San Diego, California
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15
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Dejgaard SY, Presley JF. New Method for Quantitation of Lipid Droplet Volume From Light Microscopic Images With an Application to Determination of PAT Protein Density on the Droplet Surface. J Histochem Cytochem 2018; 66:447-465. [PMID: 29361239 DOI: 10.1369/0022155417753573] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Determination of lipid droplet (LD) volume has depended on direct measurement of the diameter of individual LDs, which is not possible when LDs are small or closely apposed. To overcome this problem, we describe a new method in which a volume-fluorescence relationship is determined from automated analysis of calibration samples containing well-resolved LDs. This relationship is then used to estimate total cellular droplet volume in experimental samples, where the LDs need not be individually resolved, or to determine the volumes of individual LDs. We describe quantitatively the effects of various factors, including image noise, LD crowding, and variation in LD composition on the accuracy of this method. We then demonstrate this method by utilizing it to address a scientifically interesting question, to determine the density of green fluorescent protein (GFP)-tagged Perilipin-Adipocyte-Tail (PAT) proteins on the LD surface. We find that PAT proteins cover only a minority of the LD surface, consistent with models in which they primarily serve as scaffolds for binding of regulatory proteins and enzymes, but inconsistent with models in which their major function is to sterically block access to the droplet surface.
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Affiliation(s)
- Selma Y Dejgaard
- Department of Medical Biology, Near East University, Nicosia, Cyprus
| | - John F Presley
- Department of Anatomy and Cell Biology, McGill University, Montreal, Québec, Canada
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16
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Bombrun M, Gao H, Ranefall P, Mejhert N, Arner P, Wählby C. Quantitative high-content/high-throughput microscopy analysis of lipid droplets in subject-specific adipogenesis models. Cytometry A 2017; 91:1068-1077. [PMID: 29031005 DOI: 10.1002/cyto.a.23265] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 08/17/2017] [Accepted: 09/21/2017] [Indexed: 01/22/2023]
Abstract
Neutral lipids packed in lipid droplets (LDs) are essential as a source of fuel for organisms, and specialized storing cells, the adipocytes, provide a buffer for energy variations. Many modern-society-disorders are connected with excess accumulation or deficiency of LDs in adipose tissue. Intracellular LD number and size distribution reflect the tissue conditions, while the associated mechanisms and genes rs are still poorly understood. Large-scale genetic screens using human in vitro differentiated primary adipocytes require cell samples donated from many patients. The heterogeneity appearing between donors highlighted the need for high-throughput methods robust to individual variations. Previous image analysis algorithms failed to handle individual LDs, but focused on averages, hiding population heterogeneity. We present a new high-content analysis (HCA) technique for analysis of fat cell metabolism using data from a large-scale RNAi screen including images of more than 500 k in vitro differentiated adipocytes from three donors. The RNAi-based suppression of Perilipin 1 (PLIN1), a protein involved in the adipocyte lipid metabolism, served as a positive control, while cells treated with randomized RNA served as negative controls. We validate our segmentation by comparing our results to those of previously published methods: We also evaluate the discriminative power of different morphological features describing LD size distribution. Classification of cells as containing few large or many small LDs followed by calculating the percentage of cells in each class proved to discriminate the positive PLIN1-suppressed phenotype from the untreated negative control with an area under the receiver operating characteristic curve of 0.98. The results suggest that this HCA method offers improved segmentation and classification accuracy, and can, thus, be utilized to quantify changes in LD metabolism in response to treatment in many cell models relevant to a variety of diseases. © 2017 International Society for Advancement of Cytometry.
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Affiliation(s)
- Maxime Bombrun
- Department of Information Technology Division of Visual Information and Interaction and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Hui Gao
- Department of Biosciences and Nutrition, Novum Karolinska Institutet, 141 86 Stockholm, Sweden.,Department of Medicine, Karolinska Institutet, C2-94, Karolinska University Hospital Huddinge, 141 86 Stockholm, Sweden
| | - Petter Ranefall
- Department of Information Technology Division of Visual Information and Interaction and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Niklas Mejhert
- Department of Medicine, Karolinska Institutet, C2-94, Karolinska University Hospital Huddinge, 141 86 Stockholm, Sweden
| | - Peter Arner
- Department of Medicine, Karolinska Institutet, C2-94, Karolinska University Hospital Huddinge, 141 86 Stockholm, Sweden
| | - Carolina Wählby
- Department of Information Technology Division of Visual Information and Interaction and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
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17
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Tumova S, Kerimi A, Porter KE, Williamson G. Transendothelial glucose transport is not restricted by extracellular hyperglycaemia. Vascul Pharmacol 2016; 87:219-229. [DOI: 10.1016/j.vph.2016.11.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/29/2016] [Accepted: 11/02/2016] [Indexed: 01/18/2023]
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18
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Suppressive Effects of the Site 1 Protease (S1P) Inhibitor, PF-429242, on Dengue Virus Propagation. Viruses 2016; 8:v8020046. [PMID: 26875984 PMCID: PMC4776201 DOI: 10.3390/v8020046] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 01/24/2016] [Accepted: 02/04/2016] [Indexed: 01/08/2023] Open
Abstract
Dengue virus (DENV) infection causes one of the most widespread mosquito-borne diseases in the world. Despite the great need, effective vaccines and practical antiviral therapies are still under development. Intracellular lipid levels are regulated by sterol regulatory elements-binding proteins (SREBPs), which are activated by serine protease, site 1 protease (S1P). Small compound PF-429242 is known as a S1P inhibitor and the antivirus effects have been reported in some viruses. In this study, we examined the anti-DENV effects of PF-429242 using all four serotypes of DENV by several primate-derived cell lines. Moreover, emergence of drug-resistant DENV mutants was assessed by sequential passages with the drug. DENV dependency on intracellular lipids during their infection was also evaluated by adding extracellular lipids. The addition of PF-429242 showed suppression of viral propagation in all DENV serotypes. We showed that drug-resistant DENV mutants are unlikely to emerge after five times sequential passages through treatment with PF-429242. Although the levels of intracellular cholesterol and lipid droplets were reduced by PF-429242, viral propagations were not recovered by addition of exogenous cholesterol or fatty acids, indicating that the reduction of LD and cholesterol caused by PF-429242 treatment is not related to its mechanism of action against DENV propagation. Our results suggest that PF-429242 is a promising candidate for an anti-DENV agent.
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19
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Metformin Prevents Fatty Liver and Improves Balance of White/Brown Adipose in an Obesity Mouse Model by Inducing FGF21. Mediators Inflamm 2016; 2016:5813030. [PMID: 27057099 PMCID: PMC4745345 DOI: 10.1155/2016/5813030] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 11/23/2015] [Accepted: 11/25/2015] [Indexed: 02/06/2023] Open
Abstract
Obesity and its associated metabolic disorders are related to the onset of fatty liver and the balance of white adipose tissue (WAT) and brown adipose tissue (BAT). We hypothesized that metformin, an effective pharmacological treatment for type 2 diabetes, would inhibit white adipogenesis, fatty liver, and metabolic dysfunction. Metformin was treated daily for 14 weeks in a high-fat dieting C57BL/6J mice. Serum biomarkers were analyzed and protein level was assessed using confocal staining or flow cytometry. The development of lipid drops in the liver cells and white adipocyte was measured using hematoxylin and eosin or Oil Red O stains. Gene expressions were analyzed with quantitative real-time PCR. Metformin treatment decreased the body weight and improved the metabolic profile of obese mice. In obese mice, metformin also induced the expression of BAT-related markers and increased fibroblast growth factor (FGF) 21 expression in the liver and in white adipocyte. Metformin suppressed white adipocyte differentiation via induction of FGF21. Metformin improves Treg/Th17 balance in CD4+ T cells in mice with high-fat diet-induced obesity. Metformin also improves glucose metabolism and metabolic disorder. Interleukin-17 deficiency also decreases inflammation in mice. Therefore, metformin may be therapeutically useful for the treatment of obesity and metabolic dysfunction.
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20
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Krauß SD, Petersen D, Niedieker D, Fricke I, Freier E, El-Mashtoly SF, Gerwert K, Mosig A. Colocalization of fluorescence and Raman microscopic images for the identification of subcellular compartments: a validation study. Analyst 2015; 140:2360-8. [DOI: 10.1039/c4an02153c] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
This paper introduces algorithms for identifying overlapping observations between Raman and fluorescence microscopic images of one and the same sample.
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Affiliation(s)
- Sascha D. Krauß
- Department of Biophysics
- Ruhr-University Bochum
- 44780 Bochum
- Germany
| | - Dennis Petersen
- Department of Biophysics
- Ruhr-University Bochum
- 44780 Bochum
- Germany
| | - Daniel Niedieker
- Department of Biophysics
- Ruhr-University Bochum
- 44780 Bochum
- Germany
| | - Inka Fricke
- Department of Biophysics
- Ruhr-University Bochum
- 44780 Bochum
- Germany
| | - Erik Freier
- Department of Biophysics
- Ruhr-University Bochum
- 44780 Bochum
- Germany
| | | | - Klaus Gerwert
- Department of Biophysics
- Ruhr-University Bochum
- 44780 Bochum
- Germany
| | - Axel Mosig
- Department of Biophysics
- Ruhr-University Bochum
- 44780 Bochum
- Germany
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21
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Sims JK, Rohr B, Miller E, Lee K. Automated Image Processing for Spatially Resolved Analysis of Lipid Droplets in Cultured 3T3-L1 Adipocytes. Tissue Eng Part C Methods 2014; 21:605-13. [PMID: 25390760 DOI: 10.1089/ten.tec.2014.0513] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cellular hypertrophy of adipose tissue underlies many of the proposed proinflammatory mechanisms for obesity-related diseases. Adipose hypertrophy results from an accumulation of esterified lipids (triglycerides) into membrane-enclosed intracellular lipid droplets (LDs). The coupling between adipocyte metabolism and LD morphology could be exploited to investigate biochemical regulation of lipid pathways by monitoring the dynamics of LDs. This article describes an image processing method to identify LDs based on several distinctive optical and morphological characteristics of these cellular bodies as they appear under bright-field. The algorithm was developed against images of 3T3-L1 preadipocyte cultures induced to differentiate into adipocytes. We show that the calculated lipid volumes are in excellent agreement with enzymatic assay data on total intracellular triglyceride content. We also demonstrate that the image processing method can efficiently characterize the highly heterogeneous spatial distribution of LDs in a culture by showing that differentiation occurs in distinct clusters separated by regions of nearly undifferentiated cells. Prospectively, the LD detection method described in this work could be applied to time-lapse data collected with simple visible light microscopy equipment to quantitatively investigate LD dynamics.
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Affiliation(s)
- James Kenneth Sims
- 1Department of Chemical and Biological Engineering, Tufts University, Medford, Massachusetts
| | - Brian Rohr
- 1Department of Chemical and Biological Engineering, Tufts University, Medford, Massachusetts
| | - Eric Miller
- 2Department of Electrical and Computer Engineering, Tufts University, Medford, Massachusetts
| | - Kyongbum Lee
- 1Department of Chemical and Biological Engineering, Tufts University, Medford, Massachusetts
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22
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Affiliation(s)
- Vitaly V. Chaban
- MEMPHYS − Center for Biomembrane Physics, Syddansk Universitet, Odense M., 5230, Denmark
| | - Himanshu Khandelia
- MEMPHYS − Center for Biomembrane Physics, Syddansk Universitet, Odense M., 5230, Denmark
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23
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Roy D, Mondal S, Wang C, He X, Khurana A, Giri S, Hoffmann R, Jung DB, Kim SH, Chini EN, Periera JC, Folmes CD, Mariani A, Dowdy SC, Bakkum-Gamez JN, Riska SM, Oberg AL, Karoly ED, Bell LN, Chien J, Shridhar V. Loss of HSulf-1 promotes altered lipid metabolism in ovarian cancer. Cancer Metab 2014; 2:13. [PMID: 25225614 PMCID: PMC4164348 DOI: 10.1186/2049-3002-2-13] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Accepted: 07/21/2014] [Indexed: 01/12/2023] Open
Abstract
Background Loss of the endosulfatase HSulf-1 is common in ovarian cancer, upregulates heparin binding growth factor signaling and potentiates tumorigenesis and angiogenesis. However, metabolic differences between isogenic cells with and without HSulf-1 have not been characterized upon HSulf-1 suppression in vitro. Since growth factor signaling is closely tied to metabolic alterations, we determined the extent to which HSulf-1 loss affects cancer cell metabolism. Results Ingenuity pathway analysis of gene expression in HSulf-1 shRNA-silenced cells (Sh1 and Sh2 cells) compared to non-targeted control shRNA cells (NTC cells) and subsequent Kyoto Encyclopedia of Genes and Genomics (KEGG) database analysis showed altered metabolic pathways with changes in the lipid metabolism as one of the major pathways altered inSh1 and 2 cells. Untargeted global metabolomic profiling in these isogenic cell lines identified approximately 338 metabolites using GC/MS and LC/MS/MS platforms. Knockdown of HSulf-1 in OV202 cells induced significant changes in 156 metabolites associated with several metabolic pathways including amino acid, lipids, and nucleotides. Loss of HSulf-1 promoted overall fatty acid synthesis leading to enhance the metabolite levels of long chain, branched, and essential fatty acids along with sphingolipids. Furthermore, HSulf-1 loss induced the expression of lipogenic genes including FASN, SREBF1, PPARγ, and PLA2G3 stimulated lipid droplet accumulation. Conversely, re-expression of HSulf-1 in Sh1 cells reduced the lipid droplet formation. Additionally, HSulf-1 also enhanced CPT1A and fatty acid oxidation and augmented the protein expression of key lipolytic enzymes such as MAGL, DAGLA, HSL, and ASCL1. Overall, these findings suggest that loss of HSulf-1 by concomitantly enhancing fatty acid synthesis and oxidation confers a lipogenic phenotype leading to the metabolic alterations associated with the progression of ovarian cancer. Conclusions Taken together, these findings demonstrate that loss of HSulf-1 potentially contributes to the metabolic alterations associated with the progression of ovarian pathogenesis, specifically impacting the lipogenic phenotype of ovarian cancer cells that can be therapeutically targeted.
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Affiliation(s)
- Debarshi Roy
- Department of Experimental Pathology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Susmita Mondal
- Department of Experimental Pathology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Chen Wang
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN 55905, USA
| | - Xiaoping He
- Department of Experimental Pathology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Ashwani Khurana
- Department of Experimental Pathology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | | | - Robert Hoffmann
- Department of Experimental Pathology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Deok-Beom Jung
- Cancer Preventive Material Development Research Center (CPMRC), College of Oriental Medicine, Kyunghee University, Seoul 130-701, Republic of Korea
| | - Sung H Kim
- Cancer Preventive Material Development Research Center (CPMRC), College of Oriental Medicine, Kyunghee University, Seoul 130-701, Republic of Korea
| | - Eduardo N Chini
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | | | - Clifford D Folmes
- Department of Cardiovascular Disease, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Andrea Mariani
- Department of Obstetrics and Gynecology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Sean C Dowdy
- Department of Obstetrics and Gynecology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Jamie N Bakkum-Gamez
- Department of Obstetrics and Gynecology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Shaun M Riska
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN 55905, USA
| | - Ann L Oberg
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN 55905, USA
| | | | | | - Jeremy Chien
- Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KN 66160, USA
| | - Viji Shridhar
- Department of Experimental Pathology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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24
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Germano D, Uteng M, Pognan F, Chibout SD, Wolf A. Determination of liver specific toxicities in rat hepatocytes by high content imaging during 2-week multiple treatment. Toxicol In Vitro 2014; 30:79-94. [PMID: 24933330 DOI: 10.1016/j.tiv.2014.05.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 05/13/2014] [Accepted: 05/19/2014] [Indexed: 12/26/2022]
Abstract
DILI is a major safety issue during drug development and one of the leading causes for market withdrawal. Despite many efforts made in the past, the prediction of DILI using in vitro models remains very unreliable. In the present study, the well-established hepatocyte Collagen I-Matrigel™ sandwich culture was used, mimicking chronic drug treatment after multiple incubations for 14 days. Ten drugs associated with different types of specific preclinical and clinical liver injury were evaluated at non-cytotoxic concentrations. Mrp2-mediated transport, intracellular accumulation of neutral lipids and phospholipids were selected as functional endpoints by using Cellomics™ Arrayscan® technology and assessed at five timepoints (day 1, 3, 7, 10, 14). Liver specific functional impairments after drug treatment were enhanced over time and could be monitored by HCI already after few days and before cytotoxicity. Phospholipidosis-inducing drugs Chlorpromazine and Amiodarone displayed the same response as in vivo. Cyclosporin A, Chlorpromazine, and Troglitazone inhibited Mrp2-mediated biliary transport, correlating with in vivo findings. Steatosis remained difficult to be reproduced under the current in vitro testing conditions, resulting into false negative and positive responses. The present results suggest that the repeated long-term treatment of rat hepatocytes in the Collagen I-Matrigel™ sandwich configuration might be a suitable tool for safety profiling of the potential to induce phospholipidosis and impair Mrp2-mediated transport processes, but not to predict steatosis.
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Affiliation(s)
- Davide Germano
- Discovery and Investigative Safety, Preclinical Safety, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland
| | - Marianne Uteng
- Discovery and Investigative Safety, Preclinical Safety, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland
| | - Francois Pognan
- Discovery and Investigative Safety, Preclinical Safety, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland
| | - Salah-Dine Chibout
- Discovery and Investigative Safety, Preclinical Safety, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland
| | - Armin Wolf
- Discovery and Investigative Safety, Preclinical Safety, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland.
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25
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Doan-Xuan QM, Sarvari AK, Fischer-Posovszky P, Wabitsch M, Balajthy Z, Fesus L, Bacso Z. High content analysis of differentiation and cell death in human adipocytes. Cytometry A 2013; 83:933-43. [PMID: 23846866 DOI: 10.1002/cyto.a.22333] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 06/05/2013] [Accepted: 06/10/2013] [Indexed: 12/18/2022]
Abstract
Understanding adipocyte biology and its homeostasis is in the focus of current obesity research. We aimed to introduce a high-content analysis procedure for directly visualizing and quantifying adipogenesis and adipoapoptosis by laser scanning cytometry (LSC) in a large population of cell. Slide-based image cytometry and image processing algorithms were used and optimized for high-throughput analysis of differentiating cells and apoptotic processes in cell culture at high confluence. Both preadipocytes and adipocytes were simultaneously scrutinized for lipid accumulation, texture properties, nuclear condensation, and DNA fragmentation. Adipocyte commitment was found after incubation in adipogenic medium for 3 days identified by lipid droplet formation and increased light absorption, while terminal differentiation of adipocytes occurred throughout day 9-14 with characteristic nuclear shrinkage, eccentric nuclei localization, chromatin condensation, and massive lipid deposition. Preadipocytes were shown to be more prone to tumor necrosis factor alpha (TNFα)-induced apoptosis compared to mature adipocytes. Importantly, spontaneous DNA fragmentation was observed at early stage when adipocyte commitment occurs. This DNA damage was independent from either spontaneous or induced apoptosis and probably was part of the differentiation program. © 2013 International Society for Advancement of Cytometry.
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Affiliation(s)
- Quang Minh Doan-Xuan
- Department of Biophysics and Cell Biology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary
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26
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Differential phosphorylation of perilipin 1A at the initiation of lipolysis revealed by novel monoclonal antibodies and high content analysis. PLoS One 2013; 8:e55511. [PMID: 23405163 PMCID: PMC3566132 DOI: 10.1371/journal.pone.0055511] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 01/02/2013] [Indexed: 12/03/2022] Open
Abstract
Lipolysis in adipocytes is regulated by phosphorylation of lipid droplet-associated proteins, including perilipin 1A and hormone-sensitive lipase (HSL). Perilipin 1A is potentially phosphorylated by cAMP(adenosine 3′,5′-cyclic monophosphate)-dependent protein kinase (PKA) on several sites, including conserved C-terminal residues, serine 497 (PKA-site 5) and serine 522 (PKA-site 6). To characterize perilipin 1A phosphorylation, novel monoclonal antibodies were developed, which selectively recognize perilipin 1A phosphorylation at PKA-site 5 and PKA-site 6. Utilizing these novel antibodies, as well as antibodies selectively recognizing HSL phosphorylation at serine 563 or serine 660, we used high content analysis to examine the phosphorylation of perilipin 1A and HSL in adipocytes exposed to lipolytic agents. We found that perilipin PKA-site 5 and HSL-serine 660 were phosphorylated to a similar extent in response to forskolin (FSK) and L-γ-melanocyte stimulating hormone (L-γ-MSH). In contrast, perilipin PKA-site 6 and HSL-serine 563 were phosphorylated more slowly and L-γ-MSH was a stronger agonist for these sites compared to FSK. When a panel of lipolytic agents was tested, including multiple concentrations of isoproterenol, FSK, and L-γ-MSH, the pattern of results was virtually identical for perilipin PKA-site 5 and HSL-serine 660, whereas a distinct pattern was observed for perilipin PKA-site 6 and HSL-serine 563. Notably, perilipin PKA-site 5 and HSL-serine 660 feature two arginine residues upstream from the phospho-acceptor site, which confers high affinity for PKA, whereas perilipin PKA-site 6 and HSL-serine 563 feature only a single arginine. Thus, we suggest perilipin 1A and HSL are differentially phosphorylated in a similar manner at the initiation of lipolysis and arginine residues near the target serines may influence this process.
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Kavlock R, Chandler K, Houck K, Hunter S, Judson R, Kleinstreuer N, Knudsen T, Martin M, Padilla S, Reif D, Richard A, Rotroff D, Sipes N, Dix D. Update on EPA's ToxCast program: providing high throughput decision support tools for chemical risk management. Chem Res Toxicol 2012; 25:1287-302. [PMID: 22519603 DOI: 10.1021/tx3000939] [Citation(s) in RCA: 327] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The field of toxicology is on the cusp of a major transformation in how the safety and hazard of chemicals are evaluated for potential effects on human health and the environment. Brought on by the recognition of the limitations of the current paradigm in terms of cost, time, and throughput, combined with the ever increasing power of modern biological tools to probe mechanisms of chemical-biological interactions at finer and finer resolutions, 21st century toxicology is rapidly taking shape. A key element of the new approach is a focus on the molecular and cellular pathways that are the targets of chemical interactions. By understanding toxicity in this manner, we begin to learn how chemicals cause toxicity, as opposed to merely what diseases or health effects they might cause. This deeper understanding leads to increasing confidence in identifying which populations might be at risk, significant susceptibility factors, and key influences on the shape of the dose-response curve. The U. S. Environmental Protection Agency (EPA) initiated the ToxCast, or "toxicity forecaster", program 5 years ago to gain understanding of the strengths and limitations of the new approach by starting to test relatively large numbers (hundreds) of chemicals against an equally large number of biological assays. Using computational approaches, the EPA is building decision support tools based on ToxCast in vitro screening results to help prioritize chemicals for further investigation, as well as developing predictive models for a number of health outcomes. This perspective provides a summary of the initial, proof of concept, Phase I of ToxCast that has laid the groundwork for the next phases and future directions of the program.
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Affiliation(s)
- Robert Kavlock
- National Center for Computational Toxicology, Office of Research and Development, U. S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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Kim Y, George D, Prior AM, Prasain K, Hao S, Le DD, Hua DH, Chang KO. Novel triacsin C analogs as potential antivirals against rotavirus infections. Eur J Med Chem 2012; 50:311-8. [PMID: 22365411 DOI: 10.1016/j.ejmech.2012.02.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 01/31/2012] [Accepted: 02/03/2012] [Indexed: 11/16/2022]
Abstract
Recently our group has demonstrated that cellular triglyceride (TG) levels play an important role in rotavirus replication. In this study, we further examined the roles of the key enzymes for TG synthesis (lipogenesis) in the replication of rotaviruses by using inhibitors of fatty acid synthase, long chain fatty acid acyl-CoA synthetase (ACSL), and diacylglycerol acyltransferase and acyl-CoA:cholesterol acyltransferase in association with lipid droplets of which TG is a major component. Triacsin C, a natural ACSL inhibitor from Streptomyces aureofaciens, was found to be highly effective against rotavirus replication. Thus, novel triacsin C analogs were synthesized and evaluated for their efficacies against the replication of rotaviruses in cells. Many of the analogs significantly reduced rotavirus replication, and one analog (1e) was highly effective at a nanomolar concentration range (ED(50) 0.1μM) with a high therapeutic index in cell culture. Our results suggest a crucial role of lipid metabolism in rotavirus replication, and triacsin C and/or its analogs as potential therapeutic options for rotavirus infections.
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Affiliation(s)
- Yunjeong Kim
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, 1800 Denison Avenue, Manhattan, KS 66506, USA
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Dasgupta I, Tanifum EA, Srivastava M, Phatak SS, Cavasotto CN, Analoui M, Annapragada A. Non inflammatory boronate based glucose-responsive insulin delivery systems. PLoS One 2012; 7:e29585. [PMID: 22272238 PMCID: PMC3260138 DOI: 10.1371/journal.pone.0029585] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 11/30/2011] [Indexed: 11/23/2022] Open
Abstract
Boronic acids, known to bind diols, were screened to identify non-inflammatory cross-linkers for the preparation of glucose sensitive and insulin releasing agglomerates of liposomes (Agglomerated Vesicle Technology-AVT). This was done in order to select a suitable replacement for the previously used cross-linker, ConcanavalinA (ConA), a lectin known to have both toxic and inflammatory effects in vivo. Lead-compounds were selected from screens that involved testing for inflammatory potential, cytotoxicity and glucose-binding. These were then conjugated to insulin-encapsulating nanoparticles and agglomerated via sugar-boronate ester linkages to form AVTs. In vitro, the particles demonstrated triggered release of insulin upon exposure to physiologically relevant concentrations of glucose (10 mmoles/L–40 mmoles/L). The agglomerates were also shown to be responsive to multiple spikes in glucose levels over several hours, releasing insulin at a rate defined by the concentration of the glucose trigger.
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Affiliation(s)
- Indrani Dasgupta
- School of Biomedical Informatics, The University of Texas Health Sciences Center at Houston, Houston, Texas, United States of America
| | - Eric A. Tanifum
- Department of Pediatric Radiology, Texas Children′s Hospital and Baylor College of Medicine, Houston, Texas, United States of America
| | - Mayank Srivastava
- Department of Pediatric Radiology, Texas Children′s Hospital and Baylor College of Medicine, Houston, Texas, United States of America
| | - Sharangdhar S. Phatak
- School of Biomedical Informatics, The University of Texas Health Sciences Center at Houston, Houston, Texas, United States of America
| | - Claudio N. Cavasotto
- School of Biomedical Informatics, The University of Texas Health Sciences Center at Houston, Houston, Texas, United States of America
| | - Mostafa Analoui
- Cense Biosciences Inc., Manvel, Texas, United States of America
| | - Ananth Annapragada
- Department of Pediatric Radiology, Texas Children′s Hospital and Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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Uray IP, Rodenberg JM, Bissonnette RP, Brown PH, Mancini MA. Cancer-preventive rexinoid modulates neutral lipid contents of mammary epithelial cells through a peroxisome proliferator-activated receptor γ-dependent mechanism. Mol Pharmacol 2011; 81:228-38. [PMID: 22053058 DOI: 10.1124/mol.111.072967] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Synthetic rexinoids effectively suppress both estrogen receptor-positive and estrogen receptor-negative mammary tumors in animal models, which makes them prime candidates for a novel class of cancer-preventive agents. When used in combination with chemotherapy for non-small-cell lung cancer, the rexinoid bexarotene was most effective for patients who developed hypertriglyceridemia as a side effect. Although serum triglycerides originate from the liver, the effect of bexarotene on lipogenesis in breast epithelial cells is not known. Gene expression studies with normal mammary epithelial cells indicated that rexinoids modulate lipid metabolism, particularly enzymes involved in triglyceride synthesis. High-content analysis revealed dose-dependent accumulation of neutral lipids within adipocyte differentiation-related protein-associated cytoplasmic lipid droplets after long-term bexarotene treatment. Bexarotene also induced mRNA and protein levels for peroxisome proliferator-activated receptor (PPAR) γ, whereas selective knockdown of PPARγ attenuated the induction of both lipid droplets and adipocyte differentiation-related protein. Pharmacological activation of PPARγ, but not PPARα or retinoic acid receptors, effectively induced lipid accumulation. Furthermore, the combination of the PPARγ agonist rosiglitazone with bexarotene synergistically suppressed the growth of human mammary epithelial cells and revealed a strong, nonlinear, inverse correlation of cell growth with lipid droplet accumulation in the cell population. These findings indicate that rexinoids activate a lipogenic program in mammary epithelial cells through a retinoid X receptor/PPARγ-mediated mechanism. It is noteworthy that combining low doses of bexarotene with the PPARγ agonist rosiglitazone provides effective growth suppression of mammary epithelial cells, potentially dissociating systemic adverse effects associated with standard bexarotene treatment from the antiproliferative effects on mammary epithelium.
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Affiliation(s)
- Iván P Uray
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
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McDonough PM, Ingermanson RS, Loy PA, Koon ED, Whittaker R, Laris CA, Hilton JM, Nicoll JB, Buehrer BM, Price JH. Quantification of hormone sensitive lipase phosphorylation and colocalization with lipid droplets in murine 3T3L1 and human subcutaneous adipocytes via automated digital microscopy and high-content analysis. Assay Drug Dev Technol 2011; 9:262-80. [PMID: 21186937 PMCID: PMC3102254 DOI: 10.1089/adt.2010.0302] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Lipolysis in adipocytes is associated with phosphorylation of hormone sensitive lipase (HSL) and translocation of HSL to lipid droplets. In this study, adipocytes were cultured in a high-throughput format (96-well dishes), exposed to lipolytic agents, and then fixed and labeled for nuclei, lipid droplets, and HSL (or HSL phosphorylated on serine 660 [pHSLser660]). The cells were imaged via automated digital fluorescence microscopy, and high-content analysis (HCA) methods were used to quantify HSL phosphorylation and the degree to which HSL (or pHSLser660) colocalizes with the lipid droplets. HSL:lipid droplet colocalization was quantified through use of Pearson's correlation, Mander's M1 Colocalization, and the Tanimoto coefficient. For murine 3T3L1 adipocytes, isoproterenol, Lys-γ3-melanocyte stimulating hormone, and forskolin elicited the appearance and colocalization of pHSLser660, whereas atrial natriuretic peptide (ANP) did not. For human subcutaneous adipocytes, isoproterenol, forskolin, and ANP activated HSL phosphorylation/colocalization, but Lys-γ3-melanocyte stimulating hormone had little or no effect. Since ANP activates guanosine 3',5'-cyclic monophosphate (cGMP)-dependent protein kinase, HSL serine 660 is likely a substrate for cGMP-dependent protein kinase in human adipocytes. For both adipocyte model systems, adipocytes with the greatest lipid content displayed the greatest lipolytic responses. The results for pHSLser660 were consistent with release of glycerol by the cells, a well-established assay of lipolysis, and the HCA methods yielded Z' values >0.50. The results illustrate several key differences between human and murine adipocytes and demonstrate advantages of utilizing HCA techniques to study lipolysis in cultured adipocytes.
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Warnke I, Goralczyk R, Fuhrer E, Schwager J. Dietary constituents reduce lipid accumulation in murine C3H10 T1/2 adipocytes: A novel fluorescent method to quantify fat droplets. Nutr Metab (Lond) 2011; 8:30. [PMID: 21569430 PMCID: PMC3117678 DOI: 10.1186/1743-7075-8-30] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 05/12/2011] [Indexed: 02/03/2023] Open
Abstract
Background Adipocyte volume (fat accumulation) and cell number (adipogenesis) is increased in obese individuals. Our objective was the identification of dietary constituents with inhibitory effects on triglyceride formation during adipogenesis. Therefore an in vitro adipose cell assay in murine C3H10 T1/2 cells was developed, which enabled rapid quantification of intracellular fat droplet accumulation during adipocyte differentiation. Results were corroborated by expression levels of several specific adipogenic and lipogenic genes which are known to regulate triglyceride accumulation. Methods C3H10 T1/2 adipocyte differentiation was conducted with rosiglitazone in the presence of test compounds for 7 days. Accumulation of intracellular lipid droplets was measured using the Cellomics® ArrayScan® VTI HCS reader and SpotDetector® BioApplication from ThermoFisher. Fluorescent images were automatically acquired and analysed employing the fluorescent dyes BODIPY® 493/503 and Hoechst 33342, for staining neutral lipids and localisation of nuclei, respectively. The expression levels of adipogenic and lipogenic genes, such as PPARα and PPARγ, C/EBPα, aP2, adiponectin, LPL and HSL, CPT-1β, ACC1, Glut4 and FAS, were determined by quantitative RT-PCR. Dietary ingredients including PUFAs, carotenoids, polyphenols and catechins were tested for their effect on lipid accumulation. Results The ω-3 PUFAs docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), the carotenoid β-carotene and hydroxytyrosol exhibited the strongest inhibitory effects on the rosiglitazone-stimulated lipid formation. (all-E)-lycopene and epigallocatechin gallate (EGCG) showed a moderate inhibition, whereas resveratrol did not reduce fat droplet formation. Additionally, it was demonstrated that adipogenic and lipogenic gene expression was attenuated. DHA, β-carotene and hydroxytyrosol inhibited the gene expression of PPARγ, C/EBPα, aP2 and CPT-1β. Conclusion This in vitro assay in differentiating adipocytes enables automated detection and quantification of changes in lipid droplet number, size and intensity. The observed inhibitory effects of identified dietary constituents such as ω-3 PUFAs and β-carotene correlate with the modulation of genes involved in adipocyte differentiation.
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Affiliation(s)
- Ines Warnke
- DSM Nutritional Products Ltd,; Department of Human Nutrition and Health, CH-4002, Basel, Switzerland.
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Théron L, Astruc T, Bouillier-Oudot M, Molette C, Vénien A, Peyrin F, Vitezica ZG, Fernandez X. The fusion of lipid droplets is involved in fat loss during cooking of duck "foie gras". Meat Sci 2011; 89:377-83. [PMID: 21621925 DOI: 10.1016/j.meatsci.2011.04.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 03/09/2011] [Accepted: 04/18/2011] [Indexed: 12/30/2022]
Abstract
Fat loss during cooking of duck "foie gras" is the main quality issue in processing plants. To better understand this phenomenon, a histological and ultrastructural study was conducted. The aim was to characterize changes in lipid droplets of duck "foie gras" related to fat loss during cooking. Ten fatty livers were sampled before and after cooking and prepared for optical and transmission electron microscopy. In raw livers, the lipid droplets were nearly spherical while after cooking, they were larger and lost their spherical shape. We also observed a decrease in the number of droplets after cooking, probably due to droplet fusion caused by the heat treatment. Before cooking, there were fewer lipid droplets and a higher osmium tetroxyde staining intensity in the fatty liver, which later gave a lower technological yield. Fat loss during cooking was higher when there was more fusion of lipid droplets before cooking.
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Affiliation(s)
- L Théron
- INRA, UMR 1289 Tissus Animaux Nutrition Digestion Ecosystème Métabolisme, F-31326 Castanet-Tolosan, France.
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Buehrer BM, Duffin DJ, Lea-Currie YR, Ribnicky D, Raskin I, Stephens JM, Cefalu WT, Gimble JM. Tools for the identification of bioactives impacting the metabolic syndrome: screening of a botanical extract library using subcutaneous and visceral human adipose-derived stem cell-based assays. J Nutr Biochem 2011; 23:519-25. [PMID: 21543201 DOI: 10.1016/j.jnutbio.2011.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 02/02/2011] [Accepted: 02/11/2011] [Indexed: 11/18/2022]
Abstract
Plant extracts continue to represent an untapped source of renewable therapeutic compounds for the treatment and prevention of illnesses including chronic metabolic disorders. With the increase in worldwide obesity and its related morbidities, the need for identifying safe and effective treatments is also rising. As such, use of primary human adipose-derived stem cells represents a physiologically relevant cell system to screen for bioactive agents in the prevention and treatment of obesity and its related complications. By using these cells in a primary screen, the risk and cost of identifying artifacts due to interspecies variation and immortalized cell lines is eliminated. We demonstrate that these cells can be formatted into 384-well high throughput screens to rapidly identify botanical extracts that affect lipogenesis and lipolysis. Additionally, counterscreening with human primary stem cells from distinct adipose depots can be routinely performed to identify tissue specific responses. In our study, over 500 botanical extracts were screened and 16 (2.7%) were found to affect lipogenesis and 4 (0.7%) affected lipolysis.
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Small molecules targeting hepatitis C virus-encoded NS5A cause subcellular redistribution of their target: insights into compound modes of action. J Virol 2011; 85:6353-68. [PMID: 21507963 DOI: 10.1128/jvi.00215-11] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The current standard of care for hepatitis C virus (HCV)-infected patients consists of lengthy treatment with interferon and ribavirin. To increase the effectiveness of HCV therapy, future regimens will incorporate multiple direct-acting antiviral (DAA) drugs. Recently, the HCV-encoded NS5A protein has emerged as a promising DAA target. Compounds targeting NS5A exhibit remarkable potency in vitro and demonstrate early clinical promise, suggesting that NS5A inhibitors could feature in future DAA combination therapies. Since the mechanisms through which these molecules operate are unknown, we have used NS5A inhibitors as tools to investigate their modes of action. Analysis of replicon-containing cells revealed dramatic phenotypic alterations in NS5A localization following treatment with NS5A inhibitors; NS5A was redistributed from the endoplasmic reticulum to lipid droplets. The NS5A relocalization did not occur in cells treated with other classes of HCV inhibitors, and NS5A-targeting molecules did not cause similar alterations in the localization of other HCV-encoded proteins. Time course analysis of the redistribution of NS5A revealed that the transfer of protein to lipid droplets was concomitant with the onset of inhibition, as judged by the kinetic profiles for these compounds. Furthermore, analysis of the kinetic profile of inhibition for a panel of test molecules permitted the separation of compounds into different kinetic classes based on their modes of action. Results from this approach suggested that NS5A inhibitors perturbed the function of new replication complexes, rather than acting on preformed complexes. Taken together, our data reveal novel biological consequences of NS5A inhibition, which may help enable the development of future assay platforms for the identification of new and/or different NS5A inhibitors.
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Hartig SM, He B, Long W, Buehrer BM, Mancini MA. Homeostatic levels of SRC-2 and SRC-3 promote early human adipogenesis. ACTA ACUST UNITED AC 2011; 192:55-67. [PMID: 21220509 PMCID: PMC3019557 DOI: 10.1083/jcb.201004026] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The related coactivators SRC-2 and SRC-3 interact with peroxisome proliferator activated receptor γ (PPARγ) to coordinate transcriptional circuits to promote adipogenesis. To identify potential coactivator redundancy during human adipogenesis at single cell resolution, we used high content analysis to quantify links between PPARγ, SRC-2, SRC-3, and lipogenesis. Because we detected robust increases and significant cell-cell heterogeneity in PPARγ and lipogenesis, without changes in SRC-2 or SRC-3, we hypothesized that permissive coregulator levels comprise a necessary adipogenic equilibrium. We probed this equilibrium by down-regulating SRC-2 and SRC-3 while simultaneously quantifying PPARγ. Individual or joint knockdown equally inhibits lipid accumulation by preventing lipogenic gene engagement, without affecting PPARγ protein levels. Supporting dominant, pro-adipogenic roles for SRC-2 and SRC-3, SRC-1 knockdown does not affect adipogenesis. SRC-2 and SRC-3 knockdown increases the proportion of cells in a PPARγ(hi)/lipid(lo) state while increasing phospho-PPARγ-S114, an inhibitor of PPARγ transcriptional activity and adipogenesis. Together, we demonstrate that SRC-2 and SRC-3 concomitantly promote human adipocyte differentiation by attenuating phospho-PPARγ-S114 and modulating PPARγ cellular heterogeneity.
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Affiliation(s)
- Sean M Hartig
- Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
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Abstract
Systems-level approaches have emerged that rely on analytical, microscopy-based technology for the discovery of novel drug targets and the mechanisms driving AR signaling, transcriptional activity, and ligand independence. Single cell behavior can be quantified by high-throughput microscopy methods through analysis of endogenous protein levels and localization or creation of biosensor cell lines that can simultaneously detect both acute and latent responses to known and unknown androgenic stimuli. The cell imaging and analytical protocols can be automated to discover agonist/antagonist response windows for nuclear translocation, reporter gene activity, nuclear export, and subnuclear transcription events, facilitating access to a multiplex model system that is inherently unavailable through classic biochemical approaches. In this chapter, we highlight the key steps needed for developing, conducting, and analyzing high-throughput screens to identify effectors of AR signaling.
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Whittaker R, Loy PA, Sisman E, Suyama E, Aza-Blanc P, Ingermanson RS, Price JH, McDonough PM. Identification of MicroRNAs that control lipid droplet formation and growth in hepatocytes via high-content screening. ACTA ACUST UNITED AC 2010; 15:798-805. [PMID: 20639500 DOI: 10.1177/1087057110374991] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hepatic lipid droplets (LDs) are associated with metabolic syndrome, type 2 diabetes, hepatitis C, and both alcoholic and nonalcoholic fatty liver disease. MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression at the level of translation. Approximately 1000 different miRNA species are encoded within the human genome, and many are differentially expressed by healthy and diseased liver. However, few studies have investigated the role of miRNAs in regulating LD expression. Accordingly, a high-content assay (HCA) was performed in which human hepatocytes (Huh-7 cells) were transiently transfected with 327 unique human miRNAs; the cells were then fixed, labeled for nuclei and lipid droplets, and imaged with an automated digital microscopy workstation. LD expression was analyzed on a cell-by-cell basis, using automated image analysis. Eleven miRNAs were identified that altered LDs. MiR-181d was the most efficacious inhibitor, decreasing LDs by about 60%. miRNA-181d was also confirmed to reduce cellular triglycerides and cholesterol ester via biochemical assays. Furthermore, a series of proteins was identified via miRNA target analysis, and siRNAs directed against many of these proteins also modified LDs. Thus, HCA-based screening identified novel miRNA and protein regulators of LDs and cholesterol metabolism that may be relevant to hepatic diseases arising from obesity and alcohol abuse.
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