The role of elastin degradation in the pathogenesis of liver fibrosis
Lead Research Organisation:
University of Edinburgh
Department Name: MRC Centre for Inflammation Research
Abstract
Long term or chronic liver disease, regardless of cause, results in scarring of the liver (termed fibrosis and cirrhosis). This scarring causes the liver to fail and is associated with significant illness and death. In the UK, the burden of cirrhosis has been identified by the Chief Medical Officer as a major challenge of the next decade. Currently there are no effective treatments for liver scarring. We have a programme of research investigating the factors which regulate recovery from scarring to inform and develop anti-scarring (so called anti-fibrotic) therapies.
We have recently demonstrated that if it is allowed to, the liver has a significant ability to break the scar tissue with a return towards more normal structure and function. In advanced liver disease though, the scar tissue persists and appears to be resistant to break-down. The presence of a protein called elastin seems to be critical to preventing effective breakdown of the scar tissue. In addition, we have preliminary evidence to suggest that a specialised form of inflammatory cell, the macrophage, produces a specific protein (enzyme) which breaks down elastin. Taken together these results suggest that elastin characterises irreversible scarring (cirrhosis) and that it accumulates as a result of a failure of the normal processes of breakdown.
Work we are undertaking will determine the cell source of elastin and the elastin degrading proteins and their relative levels at different stages of liver scarring (reversible and irreversible).
In addition, we will use experimental models to determine the mechanisms that make scarring resistant to breakdown and use infusions of purified inflammatory cells and specific population of stem cells to enhance scar breakdown.
Ultimately, by understanding the mechanisms regulating the turnover of elastin in liver scarring we will be better able to design effective anti-scarring therapies applicable in the clinic.
We have recently demonstrated that if it is allowed to, the liver has a significant ability to break the scar tissue with a return towards more normal structure and function. In advanced liver disease though, the scar tissue persists and appears to be resistant to break-down. The presence of a protein called elastin seems to be critical to preventing effective breakdown of the scar tissue. In addition, we have preliminary evidence to suggest that a specialised form of inflammatory cell, the macrophage, produces a specific protein (enzyme) which breaks down elastin. Taken together these results suggest that elastin characterises irreversible scarring (cirrhosis) and that it accumulates as a result of a failure of the normal processes of breakdown.
Work we are undertaking will determine the cell source of elastin and the elastin degrading proteins and their relative levels at different stages of liver scarring (reversible and irreversible).
In addition, we will use experimental models to determine the mechanisms that make scarring resistant to breakdown and use infusions of purified inflammatory cells and specific population of stem cells to enhance scar breakdown.
Ultimately, by understanding the mechanisms regulating the turnover of elastin in liver scarring we will be better able to design effective anti-scarring therapies applicable in the clinic.
Technical Summary
Currently there are no effective treatments for liver fibrosis and cirrhosis which represent major health challenges worldwide. Therefore, there is a pressing need to develop antifibrotic therapies. We have recently demonstrated that experimental liver fibrosis is reversible and that reversal is characterised by matrix degradation and apoptosis of activated (myofibroblast-like) hepatic stellate cells (the major cell mediator of fibrosis). However, following prolonged experimental injury, fibrosis develops which is not degraded even after one year of recovery. Characterisation of the septa which fail to undergo degradation indicates that they contain elastin, in contrast to those which rapidly become remodelled, which do not. These septa are also crosslinked by tissue transglutaminase (tTG), for which elastin is a substrate.
In pilot studies, we have shown elastase (MMP-12) is expressed in the liver by tissue macrophages and after conditional depletion of macrophages, hepatic elastin degradation is impaired; indicating that the macrophages are critical to spontaneous recovery from fibrosis and are an important source of MMP-12.
We propose to investigate the hypotheses that: A failure of elastin degradation characterises mature liver fibrosis. The presence of elastin facilitates matrix cross-linking which becomes resistant to MMP mediated degradation and persists even during spontaneous resolution. Initially, we propose to quantitate the relative expression, distribution and cellular source of elastin and MMP-12 in rodent models of reversible and irreversible fibrosis. These will be completed by studies of cirrhotic human liver tissue. MMP-12 knockout mice and wild type mice will be examined after induction of liver fibrosis by CCl4 injection and during spontaneous recovery to examine whether elastin persistence results from a failure of elastin degradation. We will go on to ?rescue? the phenotype of MMP-12 knockout mice by restoring a wild type macrophage genotype via either haemopoetic stem cell infusion or direct macrophage injection from wild type animals. We will use DTR mice to examine in detail the effect of selective macrophage depletion on the degradation of elastin and fibrotic tissue in livers undergoing spontaneous recovery from experimentally induced liver fibrosis. Finally we will use a novel model to determine the relative role of stellate cell/myofibroblast derived MMP-12 vs macrophage derived MMP-12 in matrix turnover by seeding the hepatic scar with MMP-12 knockout stem cell derived stellate cells or macrophages. By completion of these studies we will have defined the role of elastin and regulation of its degradation by MMP-12 in the spontaneous resolution of liver fibrosis.
In pilot studies, we have shown elastase (MMP-12) is expressed in the liver by tissue macrophages and after conditional depletion of macrophages, hepatic elastin degradation is impaired; indicating that the macrophages are critical to spontaneous recovery from fibrosis and are an important source of MMP-12.
We propose to investigate the hypotheses that: A failure of elastin degradation characterises mature liver fibrosis. The presence of elastin facilitates matrix cross-linking which becomes resistant to MMP mediated degradation and persists even during spontaneous resolution. Initially, we propose to quantitate the relative expression, distribution and cellular source of elastin and MMP-12 in rodent models of reversible and irreversible fibrosis. These will be completed by studies of cirrhotic human liver tissue. MMP-12 knockout mice and wild type mice will be examined after induction of liver fibrosis by CCl4 injection and during spontaneous recovery to examine whether elastin persistence results from a failure of elastin degradation. We will go on to ?rescue? the phenotype of MMP-12 knockout mice by restoring a wild type macrophage genotype via either haemopoetic stem cell infusion or direct macrophage injection from wild type animals. We will use DTR mice to examine in detail the effect of selective macrophage depletion on the degradation of elastin and fibrotic tissue in livers undergoing spontaneous recovery from experimentally induced liver fibrosis. Finally we will use a novel model to determine the relative role of stellate cell/myofibroblast derived MMP-12 vs macrophage derived MMP-12 in matrix turnover by seeding the hepatic scar with MMP-12 knockout stem cell derived stellate cells or macrophages. By completion of these studies we will have defined the role of elastin and regulation of its degradation by MMP-12 in the spontaneous resolution of liver fibrosis.
Publications

Argyle DJ
(2013)
ECAT-V: where clinical and research training meet.
in The Veterinary record

Bird T
(2018)
TGFß inhibition restores a regenerative response in acute liver injury by suppressing paracrine senescence
in Science Translational Medicine

Bird TG
(2013)
Bone marrow injection stimulates hepatic ductular reactions in the absence of injury via macrophage-mediated TWEAK signaling.
in Proceedings of the National Academy of Sciences of the United States of America

Boulter L
(2012)
Macrophage-derived Wnt opposes Notch signaling to specify hepatic progenitor cell fate in chronic liver disease.
in Nature medicine

Boyd K
(2015)
A "good death" with irreversible liver disease: Talking with patients and families about deteriorating health and dying.
in Clinical liver disease

Campana L
(2018)
The STAT3-IL-10-IL-6 Pathway Is a Novel Regulator of Macrophage Efferocytosis and Phenotypic Conversion in Sterile Liver Injury.
in Journal of immunology (Baltimore, Md. : 1950)

Campana L
(2017)
Regression of Liver Fibrosis.
in Seminars in liver disease

Campana L
(2015)
Stellate Cells in Health and Disease

Conti JA
(2008)
The desmoplastic reaction surrounding hepatic colorectal adenocarcinoma metastases aids tumor growth and survival via alphav integrin ligation.
in Clinical cancer research : an official journal of the American Association for Cancer Research

De Silva AN
(2008)
Unexpectedly high incidence of indigenous acute hepatitis E within South Hampshire: time for routine testing?
in Journal of medical virology

Fallowfield JA
(2007)
Scar-associated macrophages are a major source of hepatic matrix metalloproteinase-13 and facilitate the resolution of murine hepatic fibrosis.
in Journal of immunology (Baltimore, Md. : 1950)

Fallowfield JA
(2014)
Relaxin modulates human and rat hepatic myofibroblast function and ameliorates portal hypertension in vivo.
in Hepatology (Baltimore, Md.)

Filis P
(2015)
Maternal Smoking Dysregulates Protein Expression in Second Trimester Human Fetal Livers in a Sex-Specific Manner.
in The Journal of clinical endocrinology and metabolism

Fletcher J
(2008)
The inhibitory role of stromal cell mesenchyme on human embryonic stem cell hepatocyte differentiation is overcome by Wnt3a treatment.
in Cloning and stem cells

Gibbons MA
(2011)
Ly6Chi monocytes direct alternatively activated profibrotic macrophage regulation of lung fibrosis.
in American journal of respiratory and critical care medicine

Greenhalgh SN
(2013)
Origins of fibrosis: pericytes take centre stage.
in F1000prime reports

Greenhalgh SN
(2019)
Loss of Integrin avß8 in Murine Hepatocytes Accelerates Liver Regeneration.
in The American journal of pathology

Hannoun Z
(2010)
The comparison between conditioned media and serum-free media in human embryonic stem cell culture and differentiation.
in Cellular reprogramming

Hartland SN
(2009)
Active matrix metalloproteinase-2 promotes apoptosis of hepatic stellate cells via the cleavage of cellular N-cadherin.
in Liver international : official journal of the International Association for the Study of the Liver

Hay DC
(2011)
Unbiased screening of polymer libraries to define novel substrates for functional hepatocytes with inducible drug metabolism.
in Stem cell research

Hay DC
(2008)
Highly efficient differentiation of hESCs to functional hepatic endoderm requires ActivinA and Wnt3a signaling.
in Proceedings of the National Academy of Sciences of the United States of America

Henderson NC
(2008)
Galectin-3 expression and secretion links macrophages to the promotion of renal fibrosis.
in The American journal of pathology

Henderson NC
(2012)
Standing down the guard: stellate cells leave quietly.
in Gastroenterology

Ho GT
(2018)
MDR1 deficiency impairs mitochondrial homeostasis and promotes intestinal inflammation.
in Mucosal immunology

Hsieh WC
(2015)
Galectin-3 regulates hepatic progenitor cell expansion during liver injury.
in Gut
Description | Academy of Medical Sciences Intermediate Fellowship (Dr D Mole) |
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Country | United Kingdom |
Start | 09/2008 |
End | 08/2013 |
Description | Academy of Medical Sciences Intermediate Fellowship (Dr J Fallowfield) |
Amount | £743,397 (GBP) |
Funding ID | AMS-CSF3-Fallowfield |
Organisation | Academy of Medical Sciences (AMS) |
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Start | 09/2009 |
End | 08/2014 |
Description | Fellowship (Fallowfield) |
Amount | £60,000 (GBP) |
Organisation | Novartis |
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End | 01/2014 |
Description | MRC CIR Centre Core Support Grant - Renewal |
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Organisation | Medical Research Council (MRC) |
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Start | 09/2011 |
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Description | MRC Clinical Training Fellowship (Dr A Robson) |
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Country | United Kingdom |
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End | 03/2010 |
Description | MRC Clinical Training Fellowship (Dr M Gibbons) |
Amount | £239,000 (GBP) |
Organisation | Medical Research Council (MRC) |
Sector | Public |
Country | United Kingdom |
Start | 03/2007 |
End | 02/2010 |
Description | MRC Clinical Training Fellowship (Dr T Gordon-Walker) |
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Start | 04/2008 |
End | 03/2011 |
Description | MRC Collaborative Pogramme Grant (Prof CP Day) |
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Sector | Public |
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Start | 04/2007 |
End | 03/2012 |
Description | MRC Programme Grant (with S Forbes) |
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Description | MRC Strategic Grant (Forbes/Knight) |
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Start |
Description | Medical Research Council Programme Renewal |
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End | 04/2017 |
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Description | Royal College of Surgeons Vacation Bursary (Ms Aysha Ali) |
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Start | 06/2010 |
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Description | Stem Cells for Safer Medicine (Hay & Brickman) |
Amount | £180,000 (GBP) |
Organisation | Stem Cells for Safer Medicines (SC4SM) |
Sector | Charity/Non Profit |
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Start |
Description | Technology Strategy Board Grant Roslin Cellab |
Amount | £140,937 (GBP) |
Organisation | Innovate UK |
Sector | Public |
Country | United Kingdom |
Start |
Description | UKSCF/UK Stem Cell Foundation |
Amount | £1,700,000 (GBP) |
Organisation | UK Stem Cell Foundation |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 10/2008 |
End | 09/2010 |
Description | Wellcome Trust Equipment Grant (Mullins) |
Amount | £668,183 (GBP) |
Funding ID | 092155/Z/10/Z |
Organisation | Wellcome Trust |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 09/2010 |
End | 08/2015 |
Description | Wellcome Trust Intermediate Fellowship (Dr N Henderson) |
Amount | £877,220 (GBP) |
Funding ID | 085187/Z/08/Z |
Organisation | Wellcome Trust |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 02/2009 |
End | 01/2013 |
Description | Wellcome Trust Intermediate Fellowship (T Kendall) |
Amount | £867,024 (GBP) |
Funding ID | 095898 |
Organisation | Wellcome Trust |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 10/2011 |
End | 09/2015 |
Description | Wellcome Trust PhD Portfolio for Clinicians (ECAT) |
Amount | £5,000,000 (GBP) |
Organisation | Wellcome Trust |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 10/2008 |
End | 09/2013 |
Description | Wellcome Trust Research Training Fellowship (Dr D McFarlane) |
Amount | £135,404 (GBP) |
Organisation | Wellcome Trust |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 03/2007 |
End | 02/2009 |
Description | Wellcome Trust Research Training Fellowship (Dr P Ramachandran) |
Amount | £242,492 (GBP) |
Funding ID | 083869/Z/07/Z |
Organisation | Wellcome Trust |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 09/2008 |
End | 08/2011 |
Description | Wellcome Trust Research Training Fellowship (Dr T Bird) |
Amount | £240,000 (GBP) |
Funding ID | 081604/Z/06/Z |
Organisation | Wellcome Trust |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 05/2007 |
End | 04/2010 |
Description | Wellcome Trust STMTI Fellowship (V Snowdon) |
Amount | £244,706 (GBP) |
Funding ID | 096528 |
Organisation | Wellcome Trust |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 04/2011 |
End | 03/2014 |
Description | Wellcome Trust Vacation Scholarship (M Rygier) |
Amount | £1,440 (GBP) |
Organisation | Wellcome Trust |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 06/2009 |
End | 07/2009 |
Description | Wellcome Trust Vacation Scholarship (Pei Pei Lee) |
Amount | £1,400 (GBP) |
Organisation | Wellcome Trust |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 06/2009 |
End | 07/2009 |
Title | iPSC & HuESC derived hepatocytes |
Description | We have employed ActivinA and Wnt3a signalling to produce efficient levels of hepatocyte like cells (approximately 90%) which display hepatic function, including: ureagenesis, gluconeogenesis, albumin secretion and CYP1A2 activity from hESCs and iPSCs (Hay etal.,2008 ; Sullivan etal.,2010). Although hepatic endoderm (HE) generated from hESCs and iPSCs is a genotypically diverse, cheap and stable source of "hepatocytes", HE routine application is limited due to phenotypic instability in culture. Adopting an unbiased approach we screened polymer microarrays and identified a polyurethane matrix which promoted hepatic endoderm viability, hepatocellular gene expression, drug inducible metabolism and function. We have identified a manufacturable sub-cellular matrix capable of supporting long-term differentiated cell function which represents a step forward in developing scalable and phenotypicaly stable hESC derived hepatocytes. |
Type Of Material | Technology assay or reagent |
Year Produced | 2009 |
Provided To Others? | Yes |
Impact | We have employed ActivinA and Wnt3a signalling to produce efficient levels of hepatocyte like cells (approximately 90%) which display hepatic function, including: ureagenesis, gluconeogenesis, albumin secretion and CYP1A2 activity from hESCs and iPSCs (Hay etal.,2008 ; Sullivan etal.,2010). Although hepatic endoderm (HE) generated from hESCs and iPSCs is a genotypically diverse, cheap and stable source of "hepatocytes", HE routine application is limited due to phenotypic instability in culture. Adopting an unbiased approach we screened polymer microarrays and identified a polyurethane matrix which promoted hepatic endoderm viability, hepatocellular gene expression, drug inducible metabolism and function. We have identified a manufacturable sub-cellular matrix capable of supporting long-term differentiated cell function which represents a step forward in developing scalable and phenotypicaly stable hESC derived hepatocytes. |
Description | Identifying Antifibrotic Targets |
Organisation | Novartis |
Country | Global |
Sector | Private |
PI Contribution | I have acted as a consultant to the above facilitating the development of the above programme. |
Collaborator Contribution | Novartis and their predecessor Corthera have supplied recombinant relaxin and worked with us on the deployment of relaxin as an antifibrotic and portal hypotensive agent. We are currently in discussions over the feasibility of an experimental medicine study in human subjects |
Impact | Currently discusing clinical application of relaxin as antifibrotic and portal hypotensive agent |
Start Year | 2008 |
Description | Imaging Liver Fibrosis |
Organisation | Bayer |
Department | Bayer HealthCare |
Country | Germany |
Sector | Private |
PI Contribution | I have acted a s a consultant to the above facilitating the development of the above programme. |
Impact | None at present |
Start Year | 2006 |
Description | polymers for growing cells |
Organisation | University of Edinburgh |
Department | MRC Centre for Reproductive Health |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Providing liver biology expertise for extended culture of functional human hepatocyte like cells |
Collaborator Contribution | Added a multidisciplinary component to the MRC CIRAs before |
Impact | Patent : (WO/2010/106345) POLYMERS FOR GROWING CELLS |
Start Year | 2010 |
Description | polymers for growing cells |
Organisation | University of Edinburgh |
Department | School of Chemistry |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Providing liver biology expertise for extended culture of functional human hepatocyte like cells |
Collaborator Contribution | Added a multidisciplinary component to the MRC CIRAs before |
Impact | Patent : (WO/2010/106345) POLYMERS FOR GROWING CELLS |
Start Year | 2010 |
Title | Polymers for growing cells |
Description | The present invention provides a polymer substrate for use in the attachment and functioning of hepatocyte and hepatocyte like cells. In particular, the polymer substrate is a polyurethane polymer. |
IP Reference | WO2010106345 |
Protection | Patent application published |
Year Protection Granted | 2010 |
Licensed | Commercial In Confidence |
Impact | The ability to culture functional human heptocyte like cells over long periods of time in vitro |
Title | Polymers for growing cells |
Description | The present invention provides a polymer substrate for use in the attachment and functioning of hepatocyte and hepatocyte like cells. In particular, the polymer substrate is a polyurethane polymer. |
Type | Support Tool - For Fundamental Research |
Current Stage Of Development | Refinement. Non-clinical |
Year Development Stage Completed | 2009 |
Development Status | Under active development/distribution |
Impact | Ability to maintain functional human hepatocyte like cells for extended periods of culture in vitro |
Description | BASL and AASLD |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Type Of Presentation | Keynote/Invited Speaker |
Geographic Reach | International |
Primary Audience | Health professionals |
Results and Impact | Presentations have been made by our group at the major UK and North American liver disease meetings: BASL and AASLD. Presentations at the AASLD have recieved the President's commendation (top 10% of scientific presentations) |
Year(s) Of Engagement Activity | 2008,2009,2010 |
Description | Inaugural Lecture |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Type Of Presentation | Keynote/Invited Speaker |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | 1 hour public lecture with reception afterwards. Wide ranging audience from high school students |
Year(s) Of Engagement Activity | 2007 |
Description | Medical Detectives Lecture |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Type Of Presentation | Keynote/Invited Speaker |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | a public lecture as part of a series celebrating Conan Doyle's medical studentship in Edinburgh 45 mins with discusion, wide ranging audience from high school students to pensioners it was posted on youtube and I have received feedback from around the world |
Year(s) Of Engagement Activity | 2009 |
Description | Primary Futures: Who's in Health? campaign launch |
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 | Iredale launched "Who's in Health" in Scotland with the Chief Medical Officer for Scotland, Dr Catherine Calderwood at Sciennes Primary School in Edinburgh on the 1st of December. This event launched the Primary Futures Campaign to help young children understand how people in the health sector use literacy, maths and science in their jobs. |
Year(s) Of Engagement Activity | 2015 |
URL | http://news.scotland.gov.uk/News/Primary-Futures-Who-s-In-Health-1fd9.aspx |
Description | Public Presentation |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | Yes |
Type Of Presentation | Keynote/Invited Speaker |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | A public presentation with colleagues from Oxford and KCL exploring the potential of regenerative medicine. This was followed by an informal public breakout session. The presentation comprised MRC's contribution to the Times Cheltenham Science Festival June 2012. Wide ranging audience comprising members of the public, patients and other interested parties. Uniformly positive feedback received. |
Year(s) Of Engagement Activity | 2012 |