The study, led by the University of Leeds and Mount Sinai Hospital in Toronto, is published today in the journal Neuropsychopharmacology. It sheds light on the molecular underpinnings of learning and memory and could form the basis for research into new treatments for age-related cognitive decline, cognitive disorders such as Alzheimer’s disease and schizophrenia, and other conditions.
The researchers altered a gene in mice to inhibit the activity of an enzyme called phosphodiesterase-4B (PDE4B), which is present in many organs of the vertebrate body, including the brain.
In behavioural tests, the PDE4B-inhibited mice showed enhanced cognitive abilities.
They tended to learn faster, remember events longer and solve complex exercises better than ordinary mice.
For example, the “brainy mice” showed a better ability than ordinary mice to recognise another mouse that they had been introduced to the day before. They were also quicker at learning the location of a hidden escape platform in a test called the Morris water maze.
However, the PDE4B-inhibited mice also showed less recall of a fearful event after several days than ordinary mice.
The published findings are limited to mice and have not been tested in humans, but PDE4B is present in humans. The diminished memory of fear among mice with inhibited PDE4B could be of interest to researchers looking for treatments for pathological fear, typified by Post-Traumatic Stress Disorder (PTSD)
The PDE4B-inhibited mice also showed less anxiety. They spent more time in open, brightly-lit spaces than ordinary mice, which preferred dark, enclosed spaces.
Ordinary mice are naturally fearful of cats, but the PDE4B-inhibited mice showed a decreased fear response to cat urine, suggesting that one effect of inhibiting PDE4B could be an increase in risk-taking behaviour.
So, while the PDE4B-inhibited mice excelled at solving complex exercises, their low levels of anxiety could be counterproductive for a wild mouse.
Dr Steve Clapcote, Lecturer in Pharmacology in the University of Leeds’ School of Biomedical Sciences, led the study. He said: “Cognitive impairments are currently poorly treated, so I’m excited that our work using mice has identified phosphodiesterase-4B as a promising target for potential new treatments”.
The researchers are now working on developing drugs that will specifically inhibit PDE4B. These drugs will be tested in animals to see whether any would be suitable for clinical trials in humans.
Dr Alexander McGirr, a psychiatrist in training at the University of British Columbia, who co-led the study, said: ""In the future, medicines targeting PDE4B may potentially improve the lives of individuals with neurocognitive disorders and life-impairing anxiety, and they may have a time-limited role after traumatic events.”
Dr Laura Phipps of Alzheimer’s Research UK, who were not involved in the study, said:
“This study highlights a potentially important role for the PDE4B gene in learning and memory in mice, but further studies will be needed to know whether the findings could have implications for Alzheimer’s disease or other dementias. We’d need to see how this gene could influence memory and thinking in people to get a better idea of whether it could hold potential as a target to treat Alzheimer’s.
“There is currently a lack of effective treatments for dementia and understanding the effect of genes can be a key early step on the road to developing new drugs. With so many people affected by dementia, it is important that there is research into a wide array of treatment approaches to have the best chance of helping people sooner.”
The study involved researchers from Leeds, Mount Sinai Hospital, University of British Columbia, the University of Toronto, the National Genetic Centre in Oman, the Centre for Addiction and Mental Health in Toronto, the University of Glasgow and Swansea University. The study was funded by the UK Medical Research Council.
Dr Clapcote is available for interview.
Contact: University of Leeds press office on 0113 343 2049 or email email@example.com
The full paper: McGirr A, Lipina TV, Mun H-S, Georgiou J, Al-Amri AH, Ng E, Zhai D, Elliott C, Cameron RT, Mullins JGL, Liu F, Baillie GS, Clapcote SJ, Roder JC. (2015). ‘Specific inhibition of phosphodiesterase-4B results in anxiolysis and facilitates memory acquisition.’ is published in Neuropsychopharmacology
The paper is available on request.
Darren Tomlinson, Michelle Peckham, Megan Wright, BBSRC (Jun 2018), £150,443
Simon Walker, Royal Society (Jun 2018), £337,601
Tom Thirkell, N8 Agrifood (Jun 2018), £14,870
Stephen Muench with Glaxo SmithKline & UCB Celltech, BBSRC Industrial Partnership Award (Apr 2018), £480,225
Steve Clapcote, BBSRC (Apr 2018), £443,072
Helen Miller, Innovate UK (Apr 2018), £999,960
Elisabetta Groppelli, David Rowlands & Stanley Lemon (University of North Carolina), Medical Research Foundation Fellowship (Apr 2018), £293,494
Nikesh Patel, Medical Research Foundation fellowship (Apr 2018), £290,976
Graham Askew with colleagues in Hull and Liverpool, BBSRC (Apr 2018), £150,498
Andrew Macdonald, Neil Ranson & Richard Foster, Kidney Research UK (Apr 2018), £82,821
Jessica Kwok & Ralf Richter, Leverhulme Trust (Apr 2018), £298,273
Julie Aspden, Royal Society (Apr 2018), £20,000
Liz Duncan, Royal Society (Mar 2018), £14,602
Alex O'Neill & Ryan Seipke, BBSRC (Feb 2018), £45,489
Jim Deuchars, Royal Society (Feb 2018), £16,300
Stefan Kepinski & Netta Cohen, Leverhulme Trust (Feb 2018), £320,387
Lisa Collins, BBSRC (Feb 2018), £49,950
Alison Baker, BBSRC (Feb 2018), £30,000
Lars Jeuken, BBSRC (Feb 2018), £30,000
Nikita Gamper, BBSRC (Feb 2018), £30,000
Scott Bowen, Leducq Foundation Grant (Feb 2018), £28,470
Jessica Kwok and Ronaldo Ichiyama, International Spinal Research Trust (Feb 2018), £94,450
Alex O'Neill, Oxford Drug Design (Jan 2018), £86,098
Dave Lewis and Colleagues in South Africa, HEFCE Global Challenge Research (Jan 2018), £48,000
Sarah Calaghan, Ed White, John Colyer, Isuru Jayasinghe, BHF (Jan 2018), £128,308
Christine Foyer and Alison Baker, HEFCE GCRF Grant (Jan 2018), £71,158
Alison Baker, Yun Yung Gong and Lindsay Stringer and ICRISAT India, HEFCE GCRF Grant (Jan 2018), £27,000
Graham Askew, Simon Walker, BBSRC (Jan 2018), £699,781
Jennifer Tomlinson, Royal Society (Jan 2018), £512,801
Alison Dunn, NERC (Dec 2017), £18,000
Jennifer Tomlinson, Royal Society-Research Fellows Enhancement Award (Dec 2017), £94,681
Helen Miller, AB AGri Grant (Dec 2017), £73,600
Simon Walker, Royal Society Enhancement Award (Dec 2017), £10,000
Carrie Ferguson, Bryan Taylor, Harry Rossiter, The Physiological Society (Dec 2017), £7,392
Ralf Richter, Royal Society (Dec 2017), £6,000
Christine Foyer, British Council Newton Fund (Dec 2017), £49,840
Adrian Whitehouse and colleagues in School of Chemistry and University of Liverpool, MRC (Nov 2017), £622,319
Michelle Peckham, Neil Ransom, MRC (Nov 2017), £495,159
Dave Lewis, British Council India (Nov 2017), £22,540
Hannah Dugdale, Royal Society (Nov 2017), £15,000
Elton Zeqiraj, Royal Society (Nov 2017), £15,000
Shaunna Burke, Cancer Research UK Innovation Grant (Nov 2017), £20,000
Alex O'Neill and colleagues in Chemistry, BBSRC (Nov 2017), £431,865
Jessica Kwok, Wings for Life (Nov 2017), £87,365
Tom Bennett, BBSRC (Oct 2017), £523,679
Neil Ranson, Darren Tomlinson, BBSRC (Oct 2017), £494,318
Nikita Gamper, BBSRC (Oct 2017), £490,426
Amanda Bretman and colleagues from UEA, NERC (Oct 2017), £430,886
Juan Fontana, Rosetrees Trust consumables grant (Oct 2017), £22,500
Helen Miller, DSM Nutritional Products AG (Sep 2017), £69,988
Neil Ranson, Juan Fontana, Mark Harris, Michelle Peckham, Ralf Richter, Peter Stockley, Patricija Van Oosten-Hawle and colleagues in Engineering, FMH and MAPS, Wellcome Trust Equipment Call (Sep 2017), £418,000
Jamie Johnston, Physiological Society (Sep 2017), £10,000
Frank Sobott, Adrian Goldman, Mark Harris, Andrew Macdonald, Stephen Muench, Sheena Radford and colleagues in FMH and MAPS, Wellcome Trust Equipment Call (Aug 2017), £415,000