Cellular and molecular insights into neurodegeneration mediated by the C9orf72 gene mutation
Lead Research Organisation:
University of Edinburgh
Department Name: Centre for Clinical Brain Sciences
Abstract
The inability to study living human brain material has been a major hurdle to developing new treatments for people living with presently incurable neurodegenerative conditions, such as the dementias and motor neurone disease. Recent major discoveries in stem cell technologies, including from people with inherited forms of disease, have opened exciting new approaches, improving our understanding of underlying disease mechanisms, as well as contributing to the quest to discover new treatments. It is now possible to generate from a blood sample or skin biopsy, first unlimited numbers of master stem cells, and then the specific nerve cells that are affected in disease (for example, motor neurones), enabling the study of 'disease in a dish.'
My proposed research will exploit this approach to study living human motor neurones derived from people with the most common inherited form of motor neurone disease, due to a faulty gene, called C9orf72. I will then rigorously compare these with motor neurones grown from stem cells where the gene defect has been corrected, as well as motor neurones derived from healthy volunteers. My research focus is two-fold.
First, the latest evidence points to there being a reduction in the length of the cell's outgrowths (akin to tentacles of an octopus) in motor neurone disease. However, this remains to be proven objectively.
Second, using state-of-the-art molecular and computing techniques, I will be able to reveal the nuts and bolts - key molecular pathways - going on inside the motor neurones by studying the blueprint of the production of various critical proteins. This will allow me to identify whether there are some common themes in motor neurone disease, since it is these avenues that will hold the promise for further research and, ultimately, for finding new treatments.
My proposed research will exploit this approach to study living human motor neurones derived from people with the most common inherited form of motor neurone disease, due to a faulty gene, called C9orf72. I will then rigorously compare these with motor neurones grown from stem cells where the gene defect has been corrected, as well as motor neurones derived from healthy volunteers. My research focus is two-fold.
First, the latest evidence points to there being a reduction in the length of the cell's outgrowths (akin to tentacles of an octopus) in motor neurone disease. However, this remains to be proven objectively.
Second, using state-of-the-art molecular and computing techniques, I will be able to reveal the nuts and bolts - key molecular pathways - going on inside the motor neurones by studying the blueprint of the production of various critical proteins. This will allow me to identify whether there are some common themes in motor neurone disease, since it is these avenues that will hold the promise for further research and, ultimately, for finding new treatments.
Technical Summary
Motor neurone disease or amyotrophic lateral sclerosis (ALS) is a rapidly progressive and incurable neurodegenerative disorder, characterised by paralysis, due to loss of motor neurones (MNs). The underlying mechanism of cell-type specificity and death is unknown.
The seminal discovery that a hexanucleotide, repeat expansion in the C9orf72 gene underlies the most common cause of familial ALS (and also another, non-motor, illness, frontotemporal lobar degeneration, FTLD) makes it an attractive model for the study of the cellular and molecular mechanisms of neurodegeneration.
Combining genetic discoveries with technological advances in human induced pluripotent stem cells (iPSCs) and genome editing offers unprecedented opportunities to develop new experimental human models of neurological disease. Specifically, a potentially robust approach to interrogate the consequences of mutations in C9orf72 expressed at physiological levels is to study MNs derived from iPSCs obtained from patients with ALS carrying the C9orf72 mutant gene on an isogenic control background, permitting direct causality to be assigned to any phenotype, since the only variable is the mutation of interest.
My proposed research aims to use my host group's already validated 3 independent patient-derived mutant C9orf72 iPSC lines, with isogenic pairs, to generate MNs. Based on recent observations from both my host group's laboratory and that of others, I hypothesise that, first, there is a common cellular (morphological) phenotype - that of reduced neurite outgrowth length - and, second, there is a common molecular signature as demonstrated by examining the transcriptome. A series of experiments will inform a final set of experiments, whereby, through overexpression/knockdown of identified candidate genes or targeted pharmacological manipulation(s) of pathways identified from the transcriptomic work, a successful rescue strategy can be demonstrated to reverse the cellular phenotypic deficit.
The seminal discovery that a hexanucleotide, repeat expansion in the C9orf72 gene underlies the most common cause of familial ALS (and also another, non-motor, illness, frontotemporal lobar degeneration, FTLD) makes it an attractive model for the study of the cellular and molecular mechanisms of neurodegeneration.
Combining genetic discoveries with technological advances in human induced pluripotent stem cells (iPSCs) and genome editing offers unprecedented opportunities to develop new experimental human models of neurological disease. Specifically, a potentially robust approach to interrogate the consequences of mutations in C9orf72 expressed at physiological levels is to study MNs derived from iPSCs obtained from patients with ALS carrying the C9orf72 mutant gene on an isogenic control background, permitting direct causality to be assigned to any phenotype, since the only variable is the mutation of interest.
My proposed research aims to use my host group's already validated 3 independent patient-derived mutant C9orf72 iPSC lines, with isogenic pairs, to generate MNs. Based on recent observations from both my host group's laboratory and that of others, I hypothesise that, first, there is a common cellular (morphological) phenotype - that of reduced neurite outgrowth length - and, second, there is a common molecular signature as demonstrated by examining the transcriptome. A series of experiments will inform a final set of experiments, whereby, through overexpression/knockdown of identified candidate genes or targeted pharmacological manipulation(s) of pathways identified from the transcriptomic work, a successful rescue strategy can be demonstrated to reverse the cellular phenotypic deficit.
Planned Impact
The World Health Organisation regards neurological diseases as one of the greatest threats to public health. Moreover, neurodegenerative disease represents one of the greatest medical and economic burdens to the UK. Our understanding of the neurobiology of neurodegenerative disorders lags behind that of other neurological disorders, but there is an emerging interest into the discipline of 'regenerative medicine'. Motor neurone disease or amyotrophic lateral sclerosis (ALS) is a prototypical neurodegenerative disease of mid-adulthood, characterised by the progressive degeneration of motor neurones in the brain and spinal cord, and is invariably fatal, with death occurring typically 3-5 years after diagnosis. There is considerable overlap with dementia (frontotemporal lobar degeneration, FTLD), such that tackling this spectrum of disease is of significant scientific and clinical importance. Recent advances in induced pluripotent stem cell (iPSC) technology allows, for the first time, a rational approach to human disease modelling.
Impact on commerce and policy-makers
Despite its huge potential, the uptake of iPSC technologies by industry is rightly cautious, owing to concerns about standards and reproducibility. The work carried out in the proposed CRTF will address this by studying pathogenesis in 3 independent cell lines against an isogenic background. My host laboratory is active in raising the bar on cell standards, cross-validating SOPs, and developing phenotypic read-outs for high-content and high-throughput compatibility. They also have extensive links with Pharma; continued engagement (for instance by the attendance of Pharma partners at the annual Spring School) and translation of the research to industrial platforms will be a significant long term outcome of the Chandran-Hardingham group.
Impact on patients, carers and the public
The fact that iPSCs are patient-derived, places patients at the heart of the proposed project. iPSC technology utilises patient genetics in a way that has hitherto not been possible. Patients and carers will be engaged in the project directly through interaction with myself, as a clinician-scientist and at patient focus/support groups. More widely, I will inform and engage the public through print and online media (press releases, websites, blogs, and social media). The general public has become more aware of ALS as a result of the 'ice bucket challenge'. I will place an emphasis on explaining the technology in an accessible way, such that it can provide real hope for the future. Edinburgh Neuroscience hosts regular events engaging the public and patients with scientists.
Impact on the public and third sectors
My supervisors have formed partnerships with major charities, such as the Motor Neurone Disease Association (MNDA), MND Scotland and the Euan MacDonald Centre. I will actively contribute to these partnerships and believe that it is essential to have regular interactions with charities and their members, involving them in research activities, and meeting interested patients and their families/carers.
Impact on the economy
The economic burden of ALS alone provides a sound basis for increased research output. It is estimated that the maximum direct costs to the health and social services for a person with ALS is approximately £200,000 annually, and represents a maximum cost to health and social services in UK of £373 million a year, in addition to indirect costs to the economy of approximately £1.1 billion (Motor Neurone Disease Association). Adding to this is the current cost of dementia to the UK economy, of approximately £26 billion a year (www.alzheimers.org.uk), meaning that studying this disease spectrum that straddles diseases of both movement and cognition will have economic benefit in the longer term. iPSC technology allows for the research to be relevant, since it involves disease modelling in human (as opposed to animal) models
Impact on commerce and policy-makers
Despite its huge potential, the uptake of iPSC technologies by industry is rightly cautious, owing to concerns about standards and reproducibility. The work carried out in the proposed CRTF will address this by studying pathogenesis in 3 independent cell lines against an isogenic background. My host laboratory is active in raising the bar on cell standards, cross-validating SOPs, and developing phenotypic read-outs for high-content and high-throughput compatibility. They also have extensive links with Pharma; continued engagement (for instance by the attendance of Pharma partners at the annual Spring School) and translation of the research to industrial platforms will be a significant long term outcome of the Chandran-Hardingham group.
Impact on patients, carers and the public
The fact that iPSCs are patient-derived, places patients at the heart of the proposed project. iPSC technology utilises patient genetics in a way that has hitherto not been possible. Patients and carers will be engaged in the project directly through interaction with myself, as a clinician-scientist and at patient focus/support groups. More widely, I will inform and engage the public through print and online media (press releases, websites, blogs, and social media). The general public has become more aware of ALS as a result of the 'ice bucket challenge'. I will place an emphasis on explaining the technology in an accessible way, such that it can provide real hope for the future. Edinburgh Neuroscience hosts regular events engaging the public and patients with scientists.
Impact on the public and third sectors
My supervisors have formed partnerships with major charities, such as the Motor Neurone Disease Association (MNDA), MND Scotland and the Euan MacDonald Centre. I will actively contribute to these partnerships and believe that it is essential to have regular interactions with charities and their members, involving them in research activities, and meeting interested patients and their families/carers.
Impact on the economy
The economic burden of ALS alone provides a sound basis for increased research output. It is estimated that the maximum direct costs to the health and social services for a person with ALS is approximately £200,000 annually, and represents a maximum cost to health and social services in UK of £373 million a year, in addition to indirect costs to the economy of approximately £1.1 billion (Motor Neurone Disease Association). Adding to this is the current cost of dementia to the UK economy, of approximately £26 billion a year (www.alzheimers.org.uk), meaning that studying this disease spectrum that straddles diseases of both movement and cognition will have economic benefit in the longer term. iPSC technology allows for the research to be relevant, since it involves disease modelling in human (as opposed to animal) models
People |
ORCID iD |
| Arpan Rajesh Mehta (Principal Investigator / Fellow) |
Publications
Attwell D
(2021)
Anatomy embroiders function in Purkinje cells.
in The Lancet. Neurology
Beswick E
(2021)
A systematic review of neuropsychiatric and cognitive assessments used in clinical trials for amyotrophic lateral sclerosis.
in Journal of neurology
Braems E
(2022)
HNRNPK alleviates RNA toxicity by counteracting DNA damage in C9orf72 ALS.
in Acta neuropathologica
Compston A
(2021)
Willis and the cortical neuron.
in The Lancet. Neurology
DeFelipe J
(2021)
A museum for Cajal's Legacy.
in The Lancet. Neurology
Deisseroth K
(2021)
Form and function in the brain.
in The Lancet. Neurology
Fumagalli L
(2021)
C9orf72-derived arginine-containing dipeptide repeats associate with axonal transport machinery and impede microtubule-based motility.
in Science advances
Glasmacher SA
(2021)
Prevalence of multimorbidity and its impact on survival in people with motor neuron disease.
in European journal of neurology
Glasmacher SA
(2021)
The immediate impact of the COVID-19 pandemic on motor neuron disease services and mortality in Scotland.
in Journal of neurology
Hardingham GE
(2021)
What astrocytes need to do.
in The Lancet. Neurology
Hardingham GE
(2021)
What astrocytes need to do.
in The Lancet. Neurology
James OG
(2021)
Centenary of the oligodendrocyte.
in The Lancet. Neurology
Jayaprakash K
(2020)
Riluzole prescribing, uptake and treatment discontinuation in people with amyotrophic lateral sclerosis in Scotland.
in Journal of neurology
Licht-Mayer S
(2023)
Axonal response of mitochondria to demyelination and complex IV activity within demyelinated axons in experimental models of multiple sclerosis.
in Neuropathology and applied neurobiology
Licht-Mayer S
(2020)
Enhanced axonal response of mitochondria to demyelination offers neuroprotection: implications for multiple sclerosis.
in Acta neuropathologica
Mehta A
(2020)
Etymology and the neuron(e)
in Brain
Mehta A
(2020)
The Cajal Embroidery Project: celebrating neuroscience
in The Lancet Neurology
Mehta A
(2021)
Cajal's illustrations inspire reparative acts.
in The Lancet. Neurology
Mehta AR
(2022)
Smarter adaptive platform clinical trials in neurology: a showcase for UK innovation.
in Brain : a journal of neurology
Mehta AR
(2021)
The medicolegal landscape through the lens of COVID-19: time for reform.
in Journal of the Royal Society of Medicine
Mehta AR
(2021)
Mitochondrial bioenergetic deficits in C9orf72 amyotrophic lateral sclerosis motor neurons cause dysfunctional axonal homeostasis.
in Acta neuropathologica
Mehta AR
(2021)
Trials for neurodegenerative diseases: time to innovate.
in The Lancet. Neurology
Mehta AR
(2021)
Reply: The etymology of 'neurology', redux: early use of the term by Jean Riolan the Younger (1610).
in Brain : a journal of neurology
Mehta AR
(2022)
Assessment of Mitochondrial Trafficking as a Surrogate for Fast Axonal Transport in Human Induced Pluripotent Stem Cell-Derived Spinal Motor Neurons.
in Methods in molecular biology (Clifton, N.J.)
Mehta AR
(2019)
Targeting mitochondrial dysfunction in amyotrophic lateral sclerosis: a systematic review and meta-analysis.
in Brain communications
Mehta PR
(2022)
The impact of age on genetic testing decisions in amyotrophic lateral sclerosis.
in Brain : a journal of neurology
Ng Kee Kwong KC
(2021)
40 Years of CSF Toxicity Studies in ALS: What Have We Learnt About ALS Pathophysiology?
in Frontiers in molecular neuroscience
Ng Kee Kwong KC
(2020)
Defining novel functions for cerebrospinal fluid in ALS pathophysiology.
in Acta neuropathologica communications
Ng Kee Kwong KC
(2020)
Cerebrospinal fluid cytotoxicity in amyotrophic lateral sclerosis: a systematic review of in vitro studies.
in Brain communications
Ng Kee Kwong KC
(2020)
COVID-19, SARS and MERS: A neurological perspective.
in Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia
Pearson I
(2020)
The Prevalence and Management of Saliva Problems in Motor Neuron Disease: A 4-Year Analysis of the Scottish Motor Neuron Disease Register.
in Neuro-degenerative diseases
Perkins EM
(2021)
Altered network properties in C9ORF72 repeat expansion cortical neurons are due to synaptic dysfunction.
in Molecular neurodegeneration
Ribchester R
(2021)
Neuromuscular junctions: mind meeting matter
in The Lancet Neurology
Ribchester RR
(2021)
Neuromuscular junctions: mind meeting matter.
in The Lancet. Neurology
Warming H
(2021)
Journey down memory lane
in The Lancet Neurology
Warming HK
(2021)
Journey down memory lane.
in The Lancet. Neurology
Zoghbi HY
(2021)
Purkinje cells and their trees.
in The Lancet. Neurology
Zoghbi HY
(2021)
Purkinje cells and their trees.
in The Lancet. Neurology
| Title | Etymology of the neuron(e) |
| Description | Conceptualised artwork, and commissioned Sonia Ruiz to produce it (in watercolour). |
| Type Of Art | Artwork |
| Year Produced | 2020 |
| Impact | Published in BRAIN journal. |
| URL | https://academic.oup.com/brain/article/143/1/374/5679563 |
| Title | Graphical abstract |
| Description | Graphical abstract for use in social media/press releases to members of the public. I conceptualised/designed it, and it was then professionally illustrated by Neil Smith. |
| Type Of Art | Image |
| Year Produced | 2020 |
| Impact | Excellent feedback from stakeholders/publics. |
| URL | https://www.edinburghneuroscience.ed.ac.uk/news/diabetes-drug-gives-nerves-energy-boost-and-protects... |
| Title | The Cajal Embroidery Project |
| Description | Commissioned by the Editor-in-Chief, Dr Elena Becker-Barroso, of The Lancet Neurology (TLN), to manage the front covers for each of the 12 monthly issues of TLN in 2021. Each cover has an accompanying short piece printed in the journal. |
| Type Of Art | Artistic/Creative Exhibition |
| Year Produced | 2021 |
| Impact | Strong social media presence. Effective public engagement exercise. |
| URL | https://www.thelancet.com/journals/laneur/article/PIIS1474-4422(20)30348-3/fulltext |
| Description | COVID-19 and Medicolegal Matters |
| Geographic Reach | National |
| Policy Influence Type | Implementation circular/rapid advice/letter to e.g. Ministry of Health |
| Impact | The COVID-19 pandemic has brought out the best of the health and social care workforce globally, as acknowledged by the public. But the clapping has now stopped. Over 50,000 people who tested positive for coronavirus in the UK have died, a tragic figure that is more than double the UK Government's early 'best case scenario' estimate. Each death represents a life lost too soon, leaving behind grieving family and friends. At the same time, doctors and other healthcare professionals are exhausted and anxious, fearing both the implications of a second wave, and possible repercussions from decisions made under the strain of the pandemic. There has been polarised debate around whether doctors should be granted immunity from civil and criminal negligence claims and regulatory proceedings arising from treatment provided during COVID-19. Here, we argue that this focus on temporary statutory immunity is a distraction from pre-existing concerns that several aspects of the current medicolegal system are not fit for purpose - for doctors or for patients. Areas where there is no 'quick fix' include: the need for reform of the clinical negligence system; concerns in relation to regulatory proceedings; and the potential for BAME (black, Asian, and minority ethnic) doctors (and patients) to be disproportionately impacted in both areas. These issues are critical, since they each have a direct impact on multiple stakeholders, including on those who deliver and receive healthcare. However, there has been a tendency for these to be considered from single-minded viewpoints; accordingly, we aim in this paper to provide a more holistic view. Rather than pursuing immunity legislation, we say that the time is right for more comprehensive action, including an independent Public Inquiry to scrutinise these issues, taking into account all of the interests engaged. Our interdisciplinary work (in collaboration with Edinburgh Law School) has been widely met with positive comment and transmitted to Parliament to inform Policy. I also made a Comment in the Times newspaper, Legal section. |
| URL | https://www.thetimes.co.uk/article/doctors-dont-need-threat-of-negligence-claims-on-top-of-pandemic-... |
| Description | RS MacDonald - Scottish Neurological Research Fund |
| Amount | £15,000 (GBP) |
| Organisation | RS Macdonald Charitable Trust |
| Sector | Charity/Non Profit |
| Country | United Kingdom |
| Start | 08/2019 |
| End | 02/2020 |
| Description | Collaboration with VIB-KU Leuven (Van Damme/Van Den Bosch groups) |
| Organisation | University of Leuven |
| Country | Belgium |
| Sector | Academic/University |
| PI Contribution | Provision of human iPSC lines (Chandran Lab). Provision of original experimental; data contributing to their research study (axonal transport in C9orf72 motor neurons and paired gene-edits). |
| Collaborator Contribution | They led the work entitled: "C9orf72-derived arginine-containing dipeptide repeats associate with axonal transport machinery and impede microtubule-based motility". |
| Impact | Manuscript - currently in final revision process. Preprint available via BioRxiv. |
| Start Year | 2017 |
| Description | RS MacDonald Scottish Neurological Research Fund - Investigating the binding partners of the C9orf72 protein through immunoprecipitation and mass spectrometry |
| Organisation | University of Dundee |
| Department | MRC Protein Phosphorylation and Ubiquitylation Unit |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | Project with Professor Dario Alessi FRS. |
| Collaborator Contribution | Project with Professor Dario Alessi FRS. |
| Impact | RS MacDonald Grant secured (£15k) |
| Start Year | 2019 |
| Description | Ask the Experts session |
| Form Of Engagement Activity | A formal working group, expert panel or dialogue |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Patients, carers and/or patient groups |
| Results and Impact | Ask the Experts panel session in Glasgow just prior to the international ALS/MND symposium. This was also live broadcasted online, and we received questions both from the audience and also via the web. The session was very well received with excellent feedback and has allowed for our research to be communicated to patients, stimulating further research, and also reigniting hope for people living with this devastating disease. It also allowed me to network with leaders in the ALS research field (fellow panellists: Professor Dame Pamela Shaw, Professor Orla Hardiman). |
| Year(s) Of Engagement Activity | 2018 |
| URL | https://www.mndscotland.org.uk/research/ask-the-experts-2018/ |
| Description | BBC Scotland News broadcast |
| Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | Part of team involved with the launch of MND-SMART clinical trial (University of Edinbugh led). |
| Year(s) Of Engagement Activity | 2020 |
| URL | https://www.bbc.co.uk/news/uk-scotland-51126068 |