Burning fat: an in vivo and in vitro study of the role of PPAR-delta in regulating fat metabolism in adipose tissue

Lead Research Organisation: MRC Centre Cambridge
Department Name: MRC Human Nutrition Research

Abstract

People in the UK are getting fatter and this has consequences for both the health and wealth of the nation. Obesity increases the risk of a number of diseases including type 2 diabetes, heart disease, stroke and high blood pressure. These diseases will place an increasing burden on the National Health Service and also impair the ability of individuals to work. Central to this problem is energy balance which put basically is the difference between energy coming in as food and energy expenditure of the body. While one obvious solution is to reduce intake of high calorie foods and increase exercise in individuals, national strategies in this area have failed to halt the increase in obesity (or indeed slow the rate of increase). Furthermore, once an individual is obese it may be difficult for that person to exercise and reduce obesity. There are indications that drugs that increase the energy expenditure of the body may be used to reduce obesity and many of the risk factors for other diseases associated with obesity (e.g. insulin resistance, coronary artery disease). Several types of drugs target two proteins found in fat cells referred to as PPAR-gamma and PPAR-delta. These proteins in turn 'switch-on' genes important in either fat metabolism or fat storage. While a large amount of work has been carried out characterising PPAR-gamma, a known target for treating type II diabetes, relatively little work has been performed on PPAR-delta. This proposal sets out to investigate the role that these two receptors play in energy balance in fat cells using a combination of animal studies and in vitro cell culture. For this we will investigate the action of two drugs that target either PPAR-gamma or PPAR-delta in adipose tissue in mice and investigate how they alter the concentration of key metabolites using mass spectrometry and Nuclear Magnetic Resonance (NMR) spectroscopy, gene expression using DNA microarrays and protein content by mass spectrometry based proteomics. The data collected will then be modelled mathematically by statistics to generate hypotheses which can be pursued in cell culture based experiments. The latter approach allows us to manipulate the system more easily and hence probe mechanisms of action. This work will increase our knowledge of the mechanisms controlling energy balance in fat cells and also allow us to develop an experimental approach which could be used to understand other biochemical processes. In addition the information obtained will help better characterise a major potential drug target for obesity and associated complications.

Technical Summary

PPAR-delta is a receptor that is highly expressed in adipose tissue, and has been shown to be a potent target for the treatment of obesity. However, to date relatively little work has been carried out on this receptor compared with the other members of the PPAR family, PPAR-alpha and PPAR-gamma, both targets for current treatments of type II diabetes and aspects of the metabolic syndrome. PPAR-delta plays a major role in regulating the transition between fatty acid storage and fatty acid oxidation. Understanding the processes that allow the switch between storage and catabolism of fatty acids in adipose is one of the great challenges in understanding lipid metabolism within the body. This proposal describes a systems biology study of the action of PPAR-delta agonists in adipocytes, making use of a combined in vivo and in vitro approach using a combination of metabolomics, stable isotope analysis, transcriptomics and proteomics. The proposal will examine the metabolic consequences of administrating PPAR-delta, PPAR-gamma and PPARpan (targeting both PPAR-delta and PPAR-gamma) agonists to adipose tissue, examining both acute and chronic (two year) studies in mice using our poly-omic approach. Data fusion will be performed using a variety of multivariate statistics and the use of pathway analysis tools. Key metabolic changes will then be modelled in vitro in cell culture of 3T3-L1 cells using a combination of metabolomics, stable isotope analysis (fluxomics) and molecular interventions such as enzyme inhibitors and RNAi. In addition, to test the validity of mechanistic changes detected in the mouse to human metabolism we will investigate responses in cultured human primary cells. This proposal will both further define a pharmacological system of great relevance to the regulation of human nutrition and obesity, and provide a poly-omic dataset suitable for others to explore and develop tools for systems biology in adipose tissue.

Planned Impact

Understanding the roles of the PPARs in regulating energy balance, nutritional status and health has been a highly active area in many pharmaceutical companies both in the UK and across the globe. A number of agonists have been developed to target PPAR-alpha, PPAR-gamma or all three PPARs in order to treat type II diabetes and obesity. To illustrate this, the global sales of three PPAR agonists are listed: The PPAR-gamma agonists Rosiglitazone and pioglitazone have combined 2007 sales of about US$ 6.6 billion. The PPAR alpha agonist fenofibrate from Solvay Pharmaceuticals and Abbott yielded 2007 sales of US$ 1.9 billion. Thus, a better understanding of how PPAR-delta exerts its action may help in the development of new blockbuster drugs. Furthermore, the PPAR agonists are not without unwanted side-effects and safety concerns, at least from animal studies, and by identifying the consequences of chronic stimulation of the receptors one may be able to identify targets downstream of the PPARs which produce the beneficial effects on health without the unwanted side-effects. To ensure our research will be of relevance to the pharmaceutical industry we will continue a close collaboration between Drs Andy Nicholls and John Haselden at GlaxoSmithKline (see letter of support). This collaboration has already produced two project grants and two PhD studentships for the Griffin group. Understanding the regulation of energy balance will have benefit to the public in the UK. As stated in the application the UK is experiencing dramatic increases in obesity and the diseases it causes. This is affecting both the young and old and will have a significant health burden on the National Health Service in the future, as well as the capabilities of the UK's work force. Better understanding of how PPAR-delta upregulates beta-oxidation in adipose tissue will allow the development of drug, and even possibly nutritional interventions to stimulate the receptor. To ensure our work benefits the wider scientific community we will ensure that our results are published as manuscripts, and these, where possible, are open access. In addition Dr. Griffin has been involved in a number of schemes aimed at disseminating the results of his research to the public. This includes the 'Head Start' scheme for 17 year old scientists and the Princes Teaching Institute for school teachers. He has also appeared on BBC Radio 4's Material World discussing his research. The UK has a proud record in the development of mass spectrometry and one aspect of this proposal is the collaboration with Waters to improve structure identification in lipidomics. Although Waters is an international company it has a significant research base in Manchester (formerly Micromass). Our collaboration will help the company develop new solutions for lipidomics, particularly in software tools for interpreting the vast multivariate data produced. The project will also provide training in areas relevant to analytical biochemistry, safety assessment and drug efficacy, skills that are in demand in both academia and industry. This is important for the future of 'UK plc' as the major attraction of pharmaceutical and biotechnology companies to this country is the highly skilled work force found in the UK.

Publications

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Ashmore T (2015) Suppression of erythropoiesis by dietary nitrate. in FASEB journal : official publication of the Federation of American Societies for Experimental Biology

Related Projects

Project Reference Relationship Related To Start End Award Value
BB/H013539/1 01/07/2010 30/09/2011 £504,644
BB/H013539/2 Transfer BB/H013539/1 31/03/2012 30/12/2013 £363,927
 
Description We discovered that an important anti-diabetes drugs, called PPAR delta agonists, not only increase fatty acid metabolism in muscle but also do this in the fat cells (white adipose tissue). This has led us to investigate other mechanisms that increase fatty acid oxidation in fat cells and we have recently published a paper describing how a simple dietary modification increases fatty acid oxidation in fat in mice and rats. We are currently investigating whether this mechanism extends to humans as an anti-obesity treatment.
Exploitation Route We are currently investigating whether the mechanisms highlighted in this grant extends to humans as an anti-obesity treatment for extending life long healthy living.
Sectors Agriculture, Food and Drink,Pharmaceuticals and Medical Biotechnology

 
Description We have continued to collaborate with GSK in both general drug safety assessment and also in the area of ppar agonists. We have initiated a collaboration with Medimmune to investigate browning in white adipose tissue.
First Year Of Impact 2012
Sector Healthcare,Pharmaceuticals and Medical Biotechnology
 
Description SACN advisory committee on dietary fats
Geographic Reach National 
Policy Influence Type Participation in a advisory committee
 
Description Astra Zeneca CASE studentship
Amount £40,000 (GBP)
Organisation AstraZeneca 
Sector Private
Country United Kingdom
Start 10/2016 
End 09/2019
 
Description BBSRC Industrial CASE award
Amount £18,000 (GBP)
Organisation Selcia 
Sector Private
Country United Kingdom
Start 10/2011 
End 09/2014
 
Description COSMOS
Amount € 76,184 (EUR)
Organisation European Commission 
Department Seventh Framework Programme (FP7)
Sector Public
Country European Union (EU)
Start 11/2012 
End 10/2015
 
Description GSK-Astra Zeneca partnership awards
Amount £417,000 (GBP)
Organisation GlaxoSmithKline (GSK) 
Sector Private
Country Global
Start 04/2017 
End 03/2020
 
Description MRC CASE studentship
Amount £18,000 (GBP)
Organisation Unilever 
Sector Private
Country United Kingdom
Start 09/2011 
End 09/2014
 
Description Medimmune industrial studentship
Amount £100,000 (GBP)
Organisation MedImmune 
Department MedImmune Cambridge
Sector Private
Country United Kingdom
Start 10/2016 
End 09/2019
 
Description Metabolights: Creating the missing metabolomics community database resource.
Amount £245,000 (GBP)
Funding ID BB/I000933/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 10/2010 
End 09/2013
 
Description Optimized Metabolite Extraction, Separation, and Identification for Metabolomics
Amount £420,179 (GBP)
Organisation National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) 
Sector Public
Country United States
Start 05/2013 
End 04/2017
 
Description Technology Development Grant, MetaboFlow - the development of standardised workflows for processing metabolomics data to aid reproducible data sharing and big data initiatives
Amount £900,000 (GBP)
Funding ID 202952/B/16/Z 
Organisation Wellcome Trust 
Sector Charity/Non Profit
Country United Kingdom
Start 12/2016 
End 11/2019
 
Description Unilever CASE funded studentship
Amount £40,000 (GBP)
Funding ID NA 
Organisation Unilever 
Department Unilever Research and Development
Sector Private
Country United Kingdom
Start 10/2017 
End 09/2020
 
Description BHF programme grant on BAT 
Organisation Medical Research Council (MRC)
Department MRC Centre for Obesity and Related Metabolic Diseases
Country United Kingdom 
Sector Public 
PI Contribution Collaboration on a programme grant application to the British Heart Foundation. This has costs for lipidomics to profile eicosanoids and intact lipids in order to understand the role brown adipose tissue may play in treating atherosclerosis.
Collaborator Contribution The partner is doing the majority of the animal work and molecular biology for this project.
Impact None to date
Start Year 2012
 
Description Collaboration with Academic Rheumatology, King's College London 
Organisation King's College Hospital Charity
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution I agreed to collaborate on a grant examining the role of the mevalonate pathway in the immune system. While we will receive costs for the analyses performed this is also of interest as the immune system induced inflammation is a major cause of insulin resistance.
Collaborator Contribution See above
Impact Grant application by King's College
Start Year 2014
 
Description Collaboration with Cardiovascular medicine, University of Oxford 
Organisation University of Oxford
Country United Kingdom 
Sector Academic/University 
PI Contribution We are collaborating with Cardiovascular medicine at Oxford to understand the role metabolism plays in hypertrophic cardiomyopathy (HCM). The focus of this work is a translational medicine study of HCM. Our role is to help understand the metabolic changes that are associated with HCM, and in particular the switch from fat metabolism towards carbohydrates (fetal reprogramming).
Collaborator Contribution We ghave acquired pilot data for grant applications and written grant proposals
Impact None to date
Start Year 2013
 
Description Collaboration with Medimmune 
Organisation MedImmune
Country United States 
Sector Private 
PI Contribution We have initated a collaboration with medimmune in terms of making our expertise and facilities in metabolomics and lipidomics available to the cardiovascular and metabolic diseases group and in return we have been offered access to their high throughput cell culture facilities, we are discussing CASE studentships and also access to previously generated mouse models of obesity and fatty liver disease.
Collaborator Contribution See above!
Impact None as yet
Start Year 2014
 
Description Collaboration with university of Cagliari 
Organisation University of Cagliari
Department Department of Toxicology
Country Italy 
Sector Academic/University 
PI Contribution The University of Cagliari (department of Toxicology and Pathology) and LPS initiated a collaboration examining fatty liver disease by lipidomics and mass spectrometry imaging. The project is based around drug- induced fatty liver disease and how this develops into liver cancer. Cagliari would perform the animal studies and histology and LPS would provide lipidomic analysis.
Collaborator Contribution Generation of animal model and providing tissue samples
Impact A member of LPS was made a visiting professor of the university and we hosted a visiting student.
Start Year 2012
 
Description GlaxoSmithKline collaboration in lipidomics 
Organisation GlaxoSmithKline (GSK)
Department Safety Assessment GSK
Country United Kingdom 
Sector Private 
PI Contribution We have assisted GSK in a number of projects centred around lipidomics and metabolomics, both in diabetes and toxicology research. The most recent area has been in understanding phospholipidosis, a problem of a number of widely administered drugs, and its relevance to fatty organ disease (particularly the liver, but also fat infiltration into lungs and brain tissue) and lysosomal storage disorders.
Collaborator Contribution They will make their laboratories open to the student and have also provided consumables for the student.
Impact This has led to the CASE component being funded for an MRC ITTP studentship in the LPS group.
Start Year 2011
 
Description Johnson & Johnson PPAR 
Organisation Johnson & Johnson
Country United States 
Sector Private 
PI Contribution LPS was approached by Johnson and Johnson about collaborating to develop tools in metabolomics and lipidomics, particularly around the area of PPAR agonists. This led to a number of telpehone converstaions and face-to-face meetings.
Collaborator Contribution We have been discussing access to Johnson and Johnson compund portfolio to look at potential PPAR agonists. This collaboration finished when our main collaborator left the company.
Impact None to date
Start Year 2012
 
Description Lipidomics in Cambridge 
Organisation Babraham Institute
Country United Kingdom 
Sector Private 
PI Contribution We are collaborating to provide a comprehensive lipidomic service for academic and pharma in the cambridge area.
Collaborator Contribution This partnership will raise the profile of lipidomics in Cambridge and further afield.
Impact This has just begun.
Start Year 2011
 
Description PPAR-alpha and inflammation in humans 
Organisation University of Pennsylvania
Department Institute for Translational Medicine and Therapeutics (ITMAT)
Country United States 
Sector Academic/University 
PI Contribution LPS is collaborating with the University of Pennsylvania to look at human blood plasma from a study looking at the role PPAR-alpha plays in preventing inflammation in adipose tissue. This is an NIH-sponsored clinical research study into the Fenofibrate and Omega-3 Fatty Acid Modulation of Endotoxemia inflammation of adipose tissue (a model for inflammation associated insulin resistance). This work nicely compliments the programme work for LPS and may lead to a proposal to the NIH if the experiments are successful. Given this, LPS would like to 'absorb' the costs into the Burning fat project of LPS in the expectation that this work adds value and may pave the way for further funds in the future. Jonathan Powell suggested that the LPS group also consider using their samples for hepcidin analysis (all 3 hepcidin variants) as an off-subject but "added value" idea. HNR would not be involved. The proposal was just for information.
Collaborator Contribution They are conducting the clinical trial which will provide the samples to be analyzed at HNR.
Impact None to date
Start Year 2012
 
Description Stratifying type 2 diabetes - Exeter university 
Organisation University of Exeter
Country United Kingdom 
Sector Academic/University 
PI Contribution LPS has been working with various diabetes research groups around the UK as part of the MRC/BIS initiative to promote greater links between clinical research and pharmaceutical drug development. The "Stratifying type 2 diabetes" consortium, led by Prof Hattersley of Exeter University have received favourable reviews and an indication of £2 million funding for two clinical trails to assess drug responses to anti-diabetics and how diet, exercise and weight loss interact with drug response. The funding is subject to satisfactory responses to reviewers comments and would be considered a pilot study towards larger studies planned across five years.
Collaborator Contribution Providing samples from clinical trials.
Impact Still waiting on outcomes
Start Year 2012
 
Description Study of lipotoxicity with MRC CORD 
Organisation Medical Research Council (MRC)
Department MRC Centre for Obesity and Related Metabolic Diseases
Country United Kingdom 
Sector Public 
PI Contribution We have been measuring changes in potentially lipotoxicity species in adipose and liver tissue from animal models of obesity and type II diabetes in conjunction with MRC CORD.
Collaborator Contribution Access to animal models and facilities
Impact This is a multi-discip;inary collaboration spanning analytical chemistry, biochemistry and animal physiology. This collaboration has produced a publication this year and a grant application to the BHF which will be submitted early next year.
Start Year 2011
 
Description Thought Leader Award from Agilent 
Organisation Agilent Technologies
Country United States 
Sector Private 
PI Contribution Agilent have awarded a Thought Leader award to the head of group. This consists of a brand new ion mobility mass spectrometry plus substantial funds for research to develop this new piece of equipment. In turn we will develop new mass spectrometry tools based around ion mobility for lipid detection.
Collaborator Contribution see above.
Impact The collaboration starts in december 2014
Start Year 2014
 
Description Waters collaboration for advanced lipidomics 
Organisation Medical Research Council (MRC)
Country United Kingdom 
Sector Academic/University 
PI Contribution LPS are collaborating with Waters Corporation on the development of new chromatography methods based around super critical chromatography for lipidomic analysis. The aim is to develop methods and highlight this technology through publications and talks.
Collaborator Contribution They have CASE sponsored an MRC studentship. Waters corp have also loaned us a super critical fluid unit for 12 months to be used as part of this project.
Impact CASE sponsored an MRC studentship
Start Year 2013
 
Description Waters collaboration for advanced lipidomics 
Organisation Waters Corporation
Country United States 
Sector Public 
PI Contribution LPS are collaborating with Waters Corporation on the development of new chromatography methods based around super critical chromatography for lipidomic analysis. The aim is to develop methods and highlight this technology through publications and talks.
Collaborator Contribution They have CASE sponsored an MRC studentship. Waters corp have also loaned us a super critical fluid unit for 12 months to be used as part of this project.
Impact CASE sponsored an MRC studentship
Start Year 2013
 
Description 2nd Metabolomics Sardinian Scientific School 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact 2nd Metabolomics Sardinian Scientific School was aimed at post-grad students new to the field of metabolomics. We gave seminars and workshops in various tools and techniques in metabolomics.
Year(s) Of Engagement Activity 2016
 
Description Cambridge Science Week 2017 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact took part in Cambridge Science week and put on a display on personalised medicine and health using advanced biochemical techniques.
Year(s) Of Engagement Activity 2017
 
Description Daily Mail piece 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Type Of Presentation Paper Presentation
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact JG was approached by the Daily Mail via MRC Head Office concerning Circadian rythmns in fat. This work was published in the newspaper.

We have since been contacted to help with an Horizon programme and a piece appeared in the Wallstreet journal too.
Year(s) Of Engagement Activity 2012
 
Description Danish-UK Metabolism meeting 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Taught postgrads how to use metabolomics and lipidomics to study aspects of type 2 diabetes and related disorders.
Year(s) Of Engagement Activity 2017
 
Description Hosted a visit from Singaporean students 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach International
Primary Audience Schools
Results and Impact We hosted a visit from 6th form Singaporean students interested in applying to Cambridge as undergraduates in science related areas.

They gave me a box of chocolates!
Year(s) Of Engagement Activity 2013
 
Description Junior school science talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Workshop Facilitator
Geographic Reach Local
Primary Audience Schools
Results and Impact We have given science talks on temperature and food to approximately fifty eight year olds.

We are taking part in a larger science fair to be organised this coming year.
Year(s) Of Engagement Activity 2011,2012
 
Description Metabolic Complications in Obesity 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact A conference/workshop to promote new methods for understanding the causes and consequences of obesity.
Year(s) Of Engagement Activity 2017
 
Description Metabolomics workshop for industry 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Type Of Presentation Workshop Facilitator
Geographic Reach International
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Members of LPS co-organised a European Bioinformatics Instuitute Industrail Collaboration Workshop on Metabolomics and Lipidomics. Albert Koulman and Michael Eiden also attended this meeting.

This raised the profile of our research with industry.
Year(s) Of Engagement Activity 2012
 
Description Pint of science 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Talked about the research behind the debate about whether it is increased carbohydrate or saturated fat intake that is driving the obesity and type 2 diabetes epidemics.
Year(s) Of Engagement Activity 2017
 
Description Press release for circadian rhythms 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Type Of Presentation Paper Presentation
Geographic Reach National
Primary Audience Media (as a channel to the public)
Results and Impact We produced a press release on work published in Nature Medicine on circadian rhythms in adipose tissue.

This led to contact with a journalist producing an article on obesity and its link with sleep.
Year(s) Of Engagement Activity 2012
 
Description Sardinian summer school: Metabolomics and more. 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Sardinian summer school to spread the use of tools in metabolomics and lipidomics.
Year(s) Of Engagement Activity 2017
 
Description Science career advice to prospective undergraduates 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact This was a talk as part of an open day In cambridge to encourage students to study Natural sciences at Cambridge.

I received a number of requests for further information from students.
Year(s) Of Engagement Activity 2011,2012,2014
 
Description West African Centre for cell Biology of Infectious Pathogens College of Basic and Applied Sciences, Ghana Research Conference 2017 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Took part in a 3 day conference/workshop to discuss advances in Biology that could be applied within Western Africa to treat human disease.
Year(s) Of Engagement Activity 2017
 
Description Work experience for two school boys 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Work experience for two school boys: two school boys spent a week in my lab following members around to get some experience of what its like being a scientist.
Year(s) Of Engagement Activity 2016
 
Description Workshop at the university of cambridge to train students in physiology 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Type Of Presentation Workshop Facilitator
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Members of LPS are contributing to a four day workshop sponsored by the European Atheroscelrosis Society on Phenotyping mouse models of the Metabolic Syndrome.

None to date.
Year(s) Of Engagement Activity 2012