Researchers at King's College London have discovered how a molecular 'scaffold' which allows key parts of cells to interact, comes apart in dementia and motor neuron disease, revealing a potential new target for drug discovery.
The study, published today in Nature Communications, was funded by the UK Medical Research Council, Wellcome Trust, Alzheimer's Research UK and the Motor Neurone Disease Association.
Researchers looked at two components of cells: mitochondria, the cell 'power houses' which produce energy for the cell; and the endoplasmic reticulum (ER) which makes proteins and stores calcium for signalling processes in the cell. ER and mitochondria form close associations and these interactions enable a number of important cell functions. However the mechanism by which ER and mitochondria become linked has not, until now, been fully understood.
Professor Chris Miller, from the Institute of Psychiatry at King's and lead author of the paper, says: "At the molecular level, many processes go wrong in dementia and motor neuron disease, and one of the puzzles we're faced with is whether there is a common pathway connecting these different processes. Our study suggests that the loosening of this 'scaffold' between the mitochondria and ER in the cell may be a key process in neurodegenerative diseases such as dementia or motor neuron disease."
By studying cells in a dish, the researchers discovered that an ER protein called VAPB binds to a mitochondrial protein called PTPIP51, to form a 'scaffold' enabling ER and mitochondria to form close associations. In fact, by increasing the levels of VAPB and PTPIP51, mitochondria and ER re-organised themselves to form tighter bonds.
Many of the cell's functions that are controlled by ER-mitochondria associations are disrupted in neurodegenerative diseases, so the researchers studied how the strength of this 'scaffold' was affected in these diseases. TPD-43 is a protein which is strongly linked to Amyotrophic Lateral Sclerosis (ALS, a form of motor neuron disease) and Fronto-Temporal Dementia (FTD, the second most common form of dementia), but exactly how the protein causes neurodegeneration is not properly understood.
The researchers studied how TPD-43 affected mouse cells in a dish. They found that higher levels of TPD-43 resulted in a loosening of the scaffold which reduced ER-mitochondria bonds, affecting some important cellular functions that are linked to ALS and FTD.
Professor Miller concludes: "Our findings are important in terms of advancing our understanding of basic biology, but may also provide a potential new target for developing new treatments for these devastating disorders."
For a copy of the paper, or interview with the author, please contact Seil Collins, Press Officer, Institute of Psychiatry, King's College London seil.collins@kcl.ac.uk / (+44) 0207 848 5377 / (+44) 07718 697 176
Paper reference: Stoica, R. et al. 'ER-mitochondria associations are regulated by the VAPB-PTPIP51 interaction and are disrupted by ALS/FTP-associated TDP-43' published in Nature Communications
About King's College London
King's College London is one of the top 20 universities in the world (2013/14 QS World University Rankings) and the fourth oldest in England. It is The Sunday Times 'Best University for Graduate Employment 2012/13'. A research-led university based in the heart of London, King's has more than 25,000 students (of whom more than 10,000 are graduate students) from nearly 140 countries, and more than 6,500 employees. King's is in the second phase of a £1 billion redevelopment programme which is transforming its estate.
King's has an outstanding reputation for providing world-class teaching and cutting-edge research. In the 2008 Research Assessment Exercise for British universities, 23 departments were ranked in the top quartile of British universities; over half of our academic staff work in departments that are in the top 10 per cent in the UK in their field and can thus be classed as world leading. The College is in the top seven UK universities for research earnings and has an overall annual income of nearly £554 million.
King's has a particularly distinguished reputation in the humanities, law, the sciences (including a wide range of health areas such as psychiatry, medicine, nursing and dentistry) and social sciences including international affairs. It has played a major role in many of the advances that have shaped modern life, such as the discovery of the structure of DNA and research that led to the development of radio, television, mobile phones and radar.
King's College London and Guy's and St Thomas', King's College Hospital and South London and Maudsley NHS Foundation Trusts are part of King's Health Partners. King's Health Partners Academic Health Sciences Centre (AHSC) is a pioneering global collaboration between one of the world's leading research-led universities and three of London's most successful NHS Foundation Trusts, including leading teaching hospitals and comprehensive mental health services. For more information, visit: http://www.kingshealthpartners.org.
The College is in the midst of a five-year, £500 million fundraising campaign – World questions|King's answers – created to address some of the most pressing challenges facing humanity as quickly as feasible. The campaign's five priority areas are neuroscience and mental health, leadership and society, cancer, global power and children's health. More information about the campaign is available at http://www.kcl.ac.uk/kingsanswers.
Journal
Nature Communications