Amyloid diseases such as Parkinson’s, Alzheimer’s and type-2 diabetes pose a particular problem for drug designers because they do not present a clear target structure to aim at.
Instead of the disease being linked to a single, easily identifiable species such as the active site of an enzyme or a specific receptor, amyloid diseases are associated with heterogeneous accumulations of proteins sticking together.
This is the key reason why many amyloid diseases are currently incurable.
The new study, published in Nature Chemical Biology, outlines a way of using antibiotic resistance to find chemicals capable of stopping amyloid formation.
She said: “Until now, we haven’t had effective ways to identify drugs to combat amyloid formation. Amyloid-prone proteins often don’t have a clearly defined structure, which makes it very difficult to identify areas to target with drugs.
“Also, because amyloid-causing proteins have a tendency to stick together, they can be very hard to study in the lab. This study shows a way of getting around these problems by grafting amyloid-prone sequences into enzymes which break down antibiotics.”
The study, involving researchers in the University’s School of Chemistry and the Astbury Centre for Structural Molecular Biology, exploits the complex series of adversarial relationships between molecules in a positive way to select for chemicals that counter amyloid formation.
First, amyloid-prone sequences from target proteins are attached to antibiotic degrading beta-lactamase enzymes. Bacteria carrying the modified enzymes are combined in laboratory dishes with the antibiotic. Normally, the presence of the beta-lactamase would disable the antibiotic, allowing bacterial growth.
However, the amyloid-causing sequences act as “Trojan horses” in the beta-lactamase, preventing it from attacking the antibiotic and therefore stopping the tell-tale bacterial growth. Next, the researchers add chemicals and test whether they disable the amyloid-causing sequences, freeing the beta-lactamase to attack the antibiotic and allowing bacterial growth.
Dr Janet Saunders, a researcher on the study,said: “In our research, an old enemy—anti-bacterial resistance—turns out to be our friend. When we see bacterial growth, we know we have chemicals that are obstructing amyloid formation.”
The study identified one chemical—L-dopamine—that blocks amyloid deposits forming from sequences associated with type II diabetes. However, the real significance of the work is its potential for generic use with any protein associated with amyloid disease.
Co-authorDr David Brockwell, Associate Professor in the University’s School of Molecular and Cellular Biology, said: “If you can insert a protein sequence into beta-lactamase, you are likely to be able to use this technique as a screen for chemicals capable of inhibiting its aggregation. You can screen thousands of compounds by putting them through this test.”
Professor Radford said: “It is important to stress that an efficient screen is only one step in the journey toward drug discovery. The power of our study is that it provides the first step on this path by showing us the type of molecules we should be looking at to inhibit a particular disease-causing protein.”
Another application of the new technique could be for use in the manufacture of bio-pharmaceuticals, a class of protein-based drugs that includes many of the highest grossing modern drugs.
Dr Brockwell said: “The problem with many of these new protein-based drugs is that they suffer from similar problems to those we see in amyloid diseases; they stick together. This means you can end up with potentially life-saving drugs that you cannot manufacture.
“We are investigating whether we can use our technique to work out which biopharmaceuticals will be resistant to aggregation and hence much more likely to be successful as a drug product.”
The research was funded through a Biotechnology and Biological Sciences Research Council (BBSRC) industrial CASE partnership with University of Leeds spinout Avacta Group, an AIM-listed company dedicating to providing transformational tools to life scientists.
Innovate UK and the BBSRC have provided additional funding to explore the technique’s use with bio-pharmaceuticals.
The Astbury Centre for Structural Molecular Biology at the University of Leeds is one of Europe’s leading centres for structural biology.
Its research looks at biological structures at an atomic level and is vital to finding new ways to deal with biomedical challenges including ageing, cancer, heart disease and drug resistance.
The centre has a grant portfolio of over £50 million from funders including the Wellcome Trust, the Biotechnology and Biological Sciences Research Council (BBSRC), the Medical Research Council (MRC), the Engineering and Physical Sciences Research Council (EPSRC), the European Research Council (ERC), British Heart Foundation, Cancer Research UK, Yorkshire Cancer Research, and The Bill and Melinda Gates Foundation.
Ralf Richter, David Brockwell, Eric Hewitt, Jessica Kwok, Emanuele Paci and MAPS/FMH, BBSRC (Jun 2017), £600,000
Eric Blair, Adrian Whitehouse, Nicola Stonehouse, Alison Baker, Richard Bayliss, Joan Boyes, Ryan Seipke, Sally Boxall and MAPS/FMH, BBSRC (Jun 2017), £376,000
Stefan Kepinski, Yoselin Benitez-Alfonso, Tom Bennett, Michelle Peckham, BBSRC (Jun 2017), £331,000
Roman Tuma, Lars Jeuken, Paul Millner, Sheena Radford, Peter Stockley and MAPS/FMH, BBSRC (Jun 2017), £222,000
Vas Ponnambalam, Darren Tomlinson, Stephen Wheatcroft, BHF (May 2017), £107,878
Graham Askew in collaboration with Bangor University, BBSRC (Mar 2017), £477,383
Stephen Muench, BBSRC (Mar 2017), £132,945
Nic Stonehouse, MRC (Mar 2017), £906,341
Bill Kunin, Steve Sait, BBSRC (Mar 2017), £602,831
Adrian Goldman, EU (Mar 2017), £546,576
Sheena Radford, Wellcome Trust (Mar 2017), £1,836,482
Tom Bennett, Royal Society (Mar 2017), £15,000
Jamie Johnston, Royal Society (Mar 2017), £15,000
Beatrice Filippi, Royal Society (Mar 2017), £15,000
Ryan Seipke, BBSRC (Feb 2017), £52,116
Mary O'Connell, BBSRC (Feb 2017), £46,986
Hannah Dugdale, NERC (Feb 2017), £504,138
Anastasia Zhuravleva, EPSRC (Jan 2017), £100,792
Richard Bayliss, Cancer Research UK (Jan 2017), £1,600,000
John Barr, EU (Jan 2017), £339,000
Mark Harris, Royal Society (Jan 2017), £250,000
Alison Dunn, NERC (Jan 2017), £105,000
Alex Breeze, Pancreatic Cancer Research Fund (Jan 2017), £180,000
Alison Dunn, NERC (Dec 2016), £18,000
Lisa Collins, BBSRC (Dec 2016), £1,681,835
Brendan Davies, Leverhulme Trust (Dec 2016), £247,555
Alan Benson, Mark Drinkhill, Ed White, British Heart Foundaion (Dec 2016), £217,223
Adrian Goldman, Royal Society (Dec 2016), £82,999
Lisa Roberts, Alex Breeze, Brendan Davies, Timothy Devinney, Oliver Harlen, Joseph Holden, Anthea Hucklesby, Pamela Jones, Philip Mellor, RCUK (Nov 2016), £484,172
Lisa Roberts, Alex Breeze, Brendan Davies, Timothy Devinney, Oliver Harlen, Joseph Holden, Anthea Hucklesby, Pamela Jones, Philip Mellor, Wellcome Trust (Nov 2016), £119,343
Katie Field, Rank Prize Funds (Nov 2016), £20,000
Jessica Kwok, Royal Society (Nov 2016), £14,948
John Ladbury, Cancer Research UK (Oct 2016), £4,250
Miriam Wittmann, Martin Stacey, Edward Vital, Lupus UK
(Oct 2016), £34,010
Valerie Speirs, NC3Rs
(Oct 2016), £90,000
Nicola Stonehouse, Morgan Herod, David Rowlands, BBSRC
(Sep 2016), £436,424
Joseph Cockburn, Wellcome Trust
(Sep 2016), £100,000
John Barr, Public Health England
(Sep 2016), £94,471
Helen Miller, DSM Nutritional Products A/S
(Sep 2016), £54,680
Steven Clapcote, Vitaflo International Ltd
(Sep 2016), £39,285
Juan Fontana Jordan De Urries
, Royal Society
(Sep 2016), £21,793
Jing Li, Sarah Calaghan, Mark Drinkhill, British Heart Foundation
(Sep 2016), £117,585
Sheena Radford, Alison Ashcroft, BBSRC (Sep 2016), £457,216
Patricija Van Oosten-Hawle, An-Jung Chen, David Westhead, NC3Rs
(Sep 2016), £354,456
Glyn Hemsworth, BBSRC (Sep 2016), £1,024,034
David Jayne, Paul Millner, MRC (Aug 2016), £207,860
Sheena Radford, Alison Ashcroft, BBSRC (Aug 2016), £457,215
Patricija Van Oosten-Hawle, Dave Westhead, An-Jung Chen, NC3Rs (Aug 2016), £354,456
Peter Henderson, EU - European Union
EU - European Union
(Jul 2016), £123,897
Adrian Goldman, EU - European Union
(Jul 2016), £116,290
Urwin, Howard Atkinson, NERC
(Jul 2016), £105,053
Eileen Ingham and colleagues in Engineering and M&H, EPSRC (Jul 2016), £3,867,449
Michael Colman, MRC (Jul 2016), £200,956
Tim Benton, Fresca Group Ltd
(Jul 2016), £52,082