Brain-enriched voltage-gated calcium channel isoforms: novel, genetically informed, therapeutic targets for psychiatric disorders

Lead Research Organisation: University of Oxford
Department Name: Psychiatry

Abstract

The last few years have seen substantial progress in our understanding of the genetic basis of psychiatric illnesses such as schizophrenia and bipolar disorder (also known as manic depression). It is hoped, and often claimed, that this knowledge will lead to insights into the biology of these illnesses and new therapies. However, concrete examples of this argument are lacking. This research will begin to examine how we can move from genetic insights to new therapies by focussing on arguably the most promising set of molecules arising from the recent genetic studies: the voltage gated calcium channels (VGCCs).

Calcium is an important signalling molecule and plays a key role in brain function. There is long-standing evidence that patients with bipolar disorder have abnormalities in calcium function. Recent genetic studies suggest that these abnormalities may be caused, in part, by alterations in the function of the VGCCs. These channels make attractive drug targets for treating bipolar disorder and other psychiatric disorders in which these channels are implicated. However, many different types of VGCCs are produced from a limited number of VGCC genes, and there is a lack of information about the precise types of VGCCs that are present in human brain, and how these channels are changed in psychiatric disorders and in those at higher genetic risk for these illnesses. Neither do we know how the critical brain VGCCs differ from those found elsewhere in the body. This grant will directly answer these three questions by identifying the VGCCs present and enriched in human brain, compared to other body tissues, and investigating how they are changed in association with genetic risk for psychiatric disorders, and in the diseases themselves. These studies will take advantage of a wealth of data that has already been collected, some of which we have unique access to. We will combine analysis of these existing datasets with cutting-edge experimental studies. Crucially, both our analyses and experiments will use human brain tissue. This is essential, because the number of different molecules that a single gene produces is much higher in humans than in others species, particularly in human brain, compared with other types of body tissue. Most of the studies that have investigated the types of VGCCs present in brain vs other tissues have either used animal tissue, or have looked at only a few people, which is unlikely to be sufficient to address this question. Indeed, our preliminary studies already demonstrate that much remains unknown about the types of VGCCs that are present in the human brain.

The research described here will help us to understand the key brain-enriched types of VGCC to target to improve the treatment of psychiatric illnesses, as well as investigating how genetic variation in the VGCCs increases risk for developing them. More broadly, they will also provide a test of how we can begin to move from genetic findings to new treatments.

Technical Summary

Robust genetic risk factors have been identified for psychiatric disorders. However, the pathway from gene to pathophysiological insight to novel treatment is yet to be elucidated. The research described here provides the critical first steps in this essential pipeline for arguably the most promising protein family: the voltage-gated calcium channels (VGCCs).

Calcium dysfunction has long been implicated in psychiatric illness. Genetic findings suggest a causal role for the VGCCs. Given their disease associations, clear neurobiological function and established 'druggability', they are attractive psychiatric therapeutic targets. However, progress is hampered by a lack of information about the specific VGCC isoforms present in human brain and which of these mediate disease risk. As well as being important to understand links between VGCCs and disease, this information is essential for drug development, since VGCCs also play key roles in the cardiovascular system.

This research combines computational and experimental studies to address these unknowns focussing, crucially, on human brain tissue. We will use our unique access to RNASeq data from the largest and highest-quality brain series available from healthy controls and psychiatric patients, to determine the brain transcript profile of VGCCs, and will contrast this with that of peripheral tissues, using publicly available multi-tissue RNASeq data. We will use cutting-edge methods - combining CaptureSeq and long-range PCR with long-read sequencing - to identify all VGCC isoforms, and to disambiguate the full-length transcripts (essential given their large size). We will then test for associations between VGCC isoforms and genetic risk loci, as well as disease status.

Planned Impact

In addition to the academic benefits (noted in the 'Academic Beneficiaries' section), this research will be of significant direct and indirect impacts for drug development in the field, of value to industry and ultimately to the public.

1) As outlined in the Case for Support, VGCCs are an attractive therapeutic target for bipolar disorder. However, the potential for non-selective effects of VGCC drugs is a significant barrier to progress. One of the key aims of the proposed research is to identify human, brain-enriched isoforms that should prove more selective targets for psychiatric indications (and our pilot data and the available literature already suggest that such isoforms exist). Once identified, we will work with our partners both within academia (e.g. the Structural Genomics Consortium and the Target Discovery Institutes) and industry to advance the therapeutic candidacy of these isoforms. Notably, given the lack of success in developing drugs for psychiatric disorders within the traditional pharmaceutic company R&D model, the boundaries between academia and industry are becoming increasingly blurred: several of these academic partners, in fact collaborate extensively with industrial consortia and the data that result from them are made freely-available to the scientific community.

2) In addition to the direct relevance of this research for drug development, the proposed work will, en passant, provide high quality training to post-doctoral researcher in cutting edge bioinformatics analysis techniques. This is of significant value, given the increasing wealth of large-scale data being generated (notably by consortia increasingly including both academic and industrial partners).

3) In the course of our research we have found that the neurobiological mechanisms of psychiatric disorders and their potential for improving treatment are of significant interest to the general public. The proposed research is therefore likely to provide opportunities to engage with the public to promote the public understanding of science.
 
Title Switching Perceptions at the Barbican 
Description An art exhibition and series of workshops and events focused on the role of genes in mental illness 
Type Of Art Artistic/Creative Exhibition 
Year Produced 2019 
Impact The exhibition attracted follow on funding from the Royal Society (£10k) 
URL https://www.barbican.org.uk/whats-on/2019/event/switching-perceptions
 
Title Switching Perceptions at the Bethlem Gallery 
Description I have been collaborating with Eleanor Minney, a local artist, who has developed a series of artworks inspired by my MRC-funded calcium channel work. As part of this collaboration, we worked with patients on the National Psychosis Unit at the Bethlem Hospital to explore questions around the self, mental health and mental illness, and the extent to which genetics impacts on these. The result of this project was a three-month artistic exhibition (comprising Eleanor's work and that of NPU patients) and an allied programme of events, which is ongoing. 
Type Of Art Artistic/Creative Exhibition 
Year Produced 2019 
Impact We attracted funding for our project from the Royal Society, and will be transferring elements of the Exhibition to the Barbican in Autumn 2019. 
URL http://bethlemgallery.com/event/switching-perceptions/
 
Description Invited to join Royal Society Science Policy Expert Advisory Committee (from Jan 2019)
Geographic Reach National 
Policy Influence Type Membership of a guideline committee
 
Title Long range amplicon sequencing 
Description We pioneered the combination of long range PCR and nanopore sequencing to sequence the full exon chain of a large gene (CACNA1C). This is the first time this approach has successfully been used in human post mortem material. This methodology is invaluable not only to the research in our grant, but will also be of widespread use to researchers interests in RAN splicing, since it allows, for the first time, the systematic and unambiguous characterisation of full-length coding sequences from human tissue. In addition, we have developed a bioinformatics pipeline for these analyses which we will publish separately in due course. 
Type Of Material Model of mechanisms or symptoms - human 
Year Produced 2018 
Provided To Others? Yes  
Impact As the result of our findings, we have leveraged an unrestricted educational grant (£505,000) from a pharmaceutical company in order to explore the clinical potential of our findings. 
URL https://www.biorxiv.org/content/early/2018/02/05/260562
 
Description J&J Innovations 
Organisation Johnson & Johnson
Department Johnson & Johnson Innovation (JJDC)
Country United States 
Sector Private 
PI Contribution Based on the outcome of our MRC award we established a novel collaboration with J&J Innovations, which led to an unrestricted educational grant (see funding section).
Collaborator Contribution The MRC PI instigated and leads the collaboration with J&J Innovations. Dr Nicola Hall, employed as a postdoctoral research assistant on the MRC award is now supported by the unrestricted educational grant from J&J Innovations.
Impact No new outputs as yet.
Start Year 2019
 
Description Nanopore 
Organisation Oxford Nanopore Technologies
Country United Kingdom 
Sector Private 
PI Contribution Elizabeth Tunbridge, PI, and Wilfried Haerty, coI, have met with Oxford Nanopore Technologies on a number of occasions to discuss our research and their emerging technologies. This has led to ONT being collaborators on a recent project grant submission to the BBSRC. If successful, ONT will provide in kind support and access to reagents.
Collaborator Contribution ONT are listed as collaborators on a recent project grant submission to the BBSRC. If successful, ONT will provide in kind support and access to reagents.
Impact N/A
Start Year 2019
 
Description Identification of novel CACNA1C splice variants in human brain using nanopore sequencing 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact I presented the findings of our recent bioRxov preprint at the Winter Conference for Brain Research to a mixed audience of clinicians, academics and industry scientists. following the talk I had a number of request for collaborations and further information.
Year(s) Of Engagement Activity 2018
 
Description Invited seminar: Characterization of transcriptional complexity of Voltage Gated Calcium Channels in the human brain using Nanopore long read sequencing 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Invited seminar at the Division of Evolution & Genomic Sciences, University of Manchester. The audience was composed of group leaders, University lecturers, postdoctoral researchers, graduates and undergraduates students interested in RNA biology.
Year(s) Of Engagement Activity 2018
 
Description Invited seminar: Nanopore cDNA sequencing reveals transcriptional complexity of CACNA1C gene in human brain 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited seminar in the satellite meeting of The Americal Society for Human Genetics organised by Oxford Nanopore. The audience of the seminar was composed of industrial professionals, group leaders, university professors and lecturers, postdoctoral researchers, graduates and undergraduate students. The seminar allowed to raise the personal profile of Wilfried Haerty and to raise the profile of the Earlham Institute
Year(s) Of Engagement Activity 2017
 
Description Invited seminar: Nanopore cDNA sequencing reveals transcriptional complexity of CACNA1C gene in human brain 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Invited seminar at the MRC Institute of Genetics and Molecular Medicine. The audience consisted group leaders, University professors, University Lectures, postdoctoral researchers, graduates and undergraduates students.
Year(s) Of Engagement Activity 2017
 
Description Nicola Hall London Calling 2019 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Nicola gave the plenary talk at London Calling. This led to an active collaboration with Oxford Nanopore Technology
Year(s) Of Engagement Activity 2019
URL https://vimeo.com/337887055
 
Description Poster Presentation - Cambridge Stem Cell Symposium - Characterization of splicing in the haematopoietic landscape using combined short and long read single-cell sequencing 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Poster presentation at the Cambridge Stem Cell Symposium
Year(s) Of Engagement Activity 2018
 
Description Poster presentation - Nanopore sequencing reveals the transcriptional complexity of neuropsychiatric disease genes in human brain 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Poster presentation Biology of Genomes, Cold Spring Harbor Laboratory. The audience consisted group leaders, University professors, University Lecturers, postdoctoral researchers, graduates and undergraduates students.
Year(s) Of Engagement Activity 2018
 
Description Presentation - Characterization of functional noncoding RNAs: From prediction to experimental validation. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presentation at the Evolution in the 21st Century: The Inaugural Conference of the Milner Centre for Evolution. The audience consisted group leaders, University professors, University Lecturers, postdoctoral researchers, graduates and undergraduates students.
Year(s) Of Engagement Activity 2018
 
Description Presentation - Characterization of noncoding expression and splicing diversity in the human brain 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact Invited seminar at the Institute of Ophthalmology, University College London. The audience consisted group leaders, University professors, University Lecturers, postdoctoral researchers, graduates and undergraduates students.
Year(s) Of Engagement Activity 2019
 
Description Presentation - Characterization of splicing diversity and gene fusions through Nanopore sequencing 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Selected presentation at AGBT2019, Marco Island Florida. The audience consisted of group leaders, postdoctoral researchers, graduate students, industry representatives.
Year(s) Of Engagement Activity 2019
 
Description Switching Perceptions - Barbican 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Working with artist Eleanor Minney, Elizabeth Tunbridge, coI, presented an art exhibition and series of events at the Barbican Centre, London, aiming to promote discussion about the role of genetics in mental illness. The events featured scientific events (a Cafe Scientifique and live DNA sequencing) and art events (workshops and talks), as well as a Q&A between Eleanor and Elizabeth about their collaboration.
Year(s) Of Engagement Activity 2019
URL https://www.barbican.org.uk/whats-on/2019/event/switching-perceptions
 
Description Switching Perceptions - Bethlem 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Patients, carers and/or patient groups
Results and Impact Elizabeth Tunbridge, PI, collaborated with Eleanor Minney, an artist, to conduct a series of workshops with in-patients with psychosis, in collaboration with the National Psychosis Unit, Bethlem Hospital, in which they used art as a means to promote dialogue around the experiences of severe mental illlness and the relevance of science and research to this experience. These workshops culminated in a 3 month art exhibition at the Bethlem Gallery, featuring work by Eleanor and the patients with whom we collaborated.
Year(s) Of Engagement Activity 2019
URL http://bethlemgallery.com/event/switching-perceptions/
 
Description TEDx talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Policymakers/politicians
Results and Impact I presented to policymakers as part of the TEDx Whitehall event co-organised by the Royal Society and the Government Office of Science. The talk was recorded and uploaded to YouTube as part of the TEDx network.
Year(s) Of Engagement Activity 2018
URL https://www.youtube.com/watch?v=tieFyxzBx6s&t=
 
Description Towards brain-selective calcium channel modulators for psychiatry 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Other audiences
Results and Impact I presented the findings of our recent preprint to a mixed audience of clinical and academic scientists interested in drug development for mental health at the British Association for Psychopharmacology. As the result of this meeting, we established a group of interested researchers who have recently submitted a full application for a Wellcome Trust Collaborative Award.
Year(s) Of Engagement Activity 2017
 
Description Treasury talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact I talked at HM Treasury about the potential for genetics to inform better treatments for psychiatric conditions.
Year(s) Of Engagement Activity 2018