Identifying effectors of mutant C9Orf72 ALS/FTD to combat neurodegeneration

Hexanucleotide repeat expansions (HRE) are a type of genetic mutation. When they occur in the C9orf72 gene, they are the most frequent cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Recent studies have identified several different potential triggers of nerve cell death related to this type of genetic mutation, but the specific pathways leading to ALS/FTD remain to be discovered.

The project aims to determine the pathways which trigger nereve damage by combining the power of studying human motor neurons grown in the lab, and other disease models including yeast and zebrafish. To identify and characterise potential neurodegeneration pathways we willl compare the expression of large numbers of genes in motor neurons grown from patients with C9orf72 HRE mutations, cells from such patients where the genetic mutation has been corrected, and age-matched healthy controls. We will then study these effects in more detail in yeast and test whether or not these pathways are good targets for drug therapy in a zebrafish model of ALS/FTD.

In order to achieve these ambitious aims, we have gathered three leading European teams with documented expertise in the field of stem cell biology, ALS pathology and systems biology in this highly innovative and translational project.

Hexanucleotide repeat expansions (HRE) in the C9orf72 gene are the most frequent cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Recent studies have identified formation of DNA/RNA quadruplexes, dipeptide repeat proteins (DPR) and altered nucleocytoplasmic transport as potential triggers of GGGGCC (G4C2) related neuronal cell death. The effector pathways leading to neurodegeneration in ALS/FTD remain to be discovered however.

The project aims to determine these neurodegenerative effector pathways by combining the power of pure human motor neuron cultures and non-dividing yeast, and in collaboration to validate these in zebrafish models. The specific aims are:

1. To identify potential effectors of G4C2-triggered neurodegeneration by comparative transcriptomic analysis of pure FACS-isolated motor neurons from induced pluripotent stem cells from patients with C9orf72 expansions, gene-corrected lines (using Cas9/CRISPR) and age-matched controls.
2. To classify the intermediates of G4C2-triggered neurodegeneration as aggravating, counteractive or homeostatic, by using gene overexpression/knock down in cultured motor neurons.
3. To establish their genetic hierarchy and molecular interactions in non-dividing S. pombe yeast.
4. To test the effectors as targets for pharmacological therapy in a zebrafish model of G4C2-linked ALS/FTD.

In order to achieve these ambitious aims, we have gathered three leading European teams with documented expertise in the field of stem cell biology, ALS pathology and systems biology in this highly innovative and translational project.

The aim of this project is to investigate basic disease mechanisms to promote the development of therapeutic approaches for c9ALS/FTD. There thus is likely to be high impact with numerous individuals, groups and organisations likely to gain significant benefit:
ACADEMIC BENEFICIARIES include the PI and Co-I, the Project Team, the PI's and Co-I's collaborators. Other academic beneficiaries will include groups working in the ALS/FTD and related neurodegenerative disease fields and the ALS/FTD therapeutics field.
NON-ACADEMIC BENEFICIARIES will include ALS/FTD patients, their families and charitable organisations that support ALS/FTD (e.g. the Motor Neurone Disease Association) patients and research, and those in the biotechnology, pharmaceutical and investment sectors that have interests in relation to ALS/FTD.
ACADEMIC BENEFICIARIES will benefit in the short term from direct knowledge of outputs of the present project including publications and other forms of research communication. Knowledge gained will inform future research directions, future funding applications, future research ideas and projects, and future collaborative opportunities. Longer-term, success in this project will provide fundamental knowledge in relation to the treatment of neurological disorders and will likely lead directly and indirectly to numerous long-term academic beneficiaries exploiting this knowledge in relation to other neurodegenerative diseases in particular and neurological diseases more generally.
NON-ACADEMIC BENEFICIARIES especially ALS/FTD patients will benefit directly from an advanced oligonucleotide technology, which could be available for clinical testing in approximately 5 years and offer disease modification and improved quality of life for ALS/FTD patients. ALS/FTD families will benefit immediately because such research is crucial to maintaining the morale of the community. In the medium term, families of ALS/FTD patients will benefit directly from a therapeutic agent (i.e. a product) that can be tested on relatives offering the prospect of disease modification. ALS/FTD charities and foundations play a crucial role in supporting families and funding early stage research. Finally, non-academic beneficiaries in the commercial sector are likely to benefit directly in the medium term through opportunities to acquire licences to intellectual property in relation to aspects of the technology. We will work closely with industry as the project develops to capitalise on the applications of this therapeutic approach for c9ALS/FTD, for other related neurodegenerative diseases and ultimately also for other diseases where brain drug delivery is an essential requirement.
A significant impact of the present study will be in the training and development of scientific researchers involved in the project. The staff working on the grant will be trained not only in the molecular techniques associated with the research programme but also in the rigour of reporting required for the development of a new drug. This will lead to employment prospects not only in academia but also in the biotechnology and large pharma sector.