Mitochondria are double-membrane-bound organelles that are essential for cellular energy production. A fundamental question in eukaryotic cell biology is how the biogenesis of mitochondria is achieved and regulated.
Lead Research Organisation:
The Francis Crick Institute
Department Name: UNLISTED
Abstract
Mitochondria are key parts of the cell whose central role is to produce energy in a suitable form for many biological processes. They are also involved in programmed cell death, and in maintaining appropriate levels of calcium in cells. These activities require mitochondria to communicate with the cell nucleus. Disruption of mitochondrial function can lead to a broad range of human diseases including diabetes, neurodegenerative disorders, obesity, cancer and premature ageing. Therefore, a full understanding of the basic processes in mitochondria is needed to identify the causes and consequences of mitochondrial malfunction and to enable us to design new therapies that compensate for or correct such faults. This programme will study how mitochondria are made and how their function responds to the changing requirements of the cell during growth and development. Already we have found that nutrient availability has a marked impact on mitochondrial function and so we plan to extend this work and test its applicability to diseases in mice with a view to designing and implementing clinical trials in humans.
Technical Summary
Mitochondria are double-membrane-bound organelles that are essential for cellular energy production. A fundamental question in eukaryotic cell biology is how the biogenesis of mitochondria is achieved and regulated. The process requires the targeting, import and assembly of over 1500 proteins encoded in nuclear DNA. Because mitochondria also contain their own DNA (mtDNA), which in human contributes 13 key components of the energy production apparatus, bidirectional communication between the nucleus and the mitochondria is essential to produce the desired mitochondrial activity. Our knowledge of nucleus to mitochondria (anterograde) signalling pathways coordinating mitochondrial biogenesis is expanding rapidly, and is known to involve the actions of three factors: AMP kinase, Sirt1 and PGC1a. In contrast, the characterization of the key mitochondrial factors that contribute to the regulation of biogenesis, as well as factors involved in the retrograde response (signalling from mitochondria to the nucleus) is much more limited.
Recently my group has discovered a mitochondrial protein, MPV17, with the intrinsic capacity to stimulate mitochondrial function. MPV17 is an inner mitochondrial membrane protein of unknown function, which belongs to a small family of conserved proteins. In 2006, the identification of MPV17 as the gene responsible for a form of mitochondrial DNA depletion syndrome (MDS) linked its protein product to mtDNA maintenance in vivo. Mitochondrial DNA defects were established as a cause of human disease 25 years ago, and yet there is still much that remains obscure about mtDNA maintenance. In animals and plants almost nothing is known about the anchoring, segregation or transmission of mtDNA. Furthermore, mitochondrial (DNA) dysfunction is also implicated in several common disorders, such as neurodegenerative disease, metabolic syndrome and obesity. Thus the functional characterization of proteins causing mitochondrial disease, such as MPV17, is critical to a full understanding of the role of mitochondria in human health, and the design of rational therapeutic strategies. An ability to stimulate mitochondrial biogenesis is widely recognised as the best immediate prospect for treating mitochondrial dysfunction. Hence, the new finding of MPV17’s effect on mitochondrial biogenesis provides a major new target for this approach, which will be best exploited with knowledge of its mechanism of action.
The plan is to elucidate MPV17’s mechanism of action by dissecting the protein and its partners, studying its pathological variants and the regulation of MPV17 gene expression. Specific aims are: 1) To determine the functional and physiological impacts of MPV17 ablation and mutation via proteomic and metabolite profiling of mutant cell lines and an Mpv17 knockout mouse. Fibroblast deficient cell lines, DG75 mutant and a knockout mouse model for MPV17 are already providing us with material for analysis, and they will be used in the future for transcriptomic, proteomic and metabolomic analyses, and for interventions designed to ameliorate its loss. 2) To characterize MPV17’s protein partners by affinity purification and use truncated forms of the protein to identify the key elements needed for these protein-protein interactions. 3) To dissect the stimulatory effects of MPV17 on mitochondrial biogenesis via metabolic, proteomic, and ultrastructure analyses.
Our studies of MPV17 have led to the realization that the metabolic conditions for cell growth have a major impact on mitochondrial function. We have identified nutrient growth regimes that stimulate mitochondrial protein synthesis while repressing protein synthesis in the cytosol. Therefore we predict that some mechanisms of stimulating mitochondrial capacity will repress cytosolic protein synthesis and thereby arrest cell growth and division.
Recently my group has discovered a mitochondrial protein, MPV17, with the intrinsic capacity to stimulate mitochondrial function. MPV17 is an inner mitochondrial membrane protein of unknown function, which belongs to a small family of conserved proteins. In 2006, the identification of MPV17 as the gene responsible for a form of mitochondrial DNA depletion syndrome (MDS) linked its protein product to mtDNA maintenance in vivo. Mitochondrial DNA defects were established as a cause of human disease 25 years ago, and yet there is still much that remains obscure about mtDNA maintenance. In animals and plants almost nothing is known about the anchoring, segregation or transmission of mtDNA. Furthermore, mitochondrial (DNA) dysfunction is also implicated in several common disorders, such as neurodegenerative disease, metabolic syndrome and obesity. Thus the functional characterization of proteins causing mitochondrial disease, such as MPV17, is critical to a full understanding of the role of mitochondria in human health, and the design of rational therapeutic strategies. An ability to stimulate mitochondrial biogenesis is widely recognised as the best immediate prospect for treating mitochondrial dysfunction. Hence, the new finding of MPV17’s effect on mitochondrial biogenesis provides a major new target for this approach, which will be best exploited with knowledge of its mechanism of action.
The plan is to elucidate MPV17’s mechanism of action by dissecting the protein and its partners, studying its pathological variants and the regulation of MPV17 gene expression. Specific aims are: 1) To determine the functional and physiological impacts of MPV17 ablation and mutation via proteomic and metabolite profiling of mutant cell lines and an Mpv17 knockout mouse. Fibroblast deficient cell lines, DG75 mutant and a knockout mouse model for MPV17 are already providing us with material for analysis, and they will be used in the future for transcriptomic, proteomic and metabolomic analyses, and for interventions designed to ameliorate its loss. 2) To characterize MPV17’s protein partners by affinity purification and use truncated forms of the protein to identify the key elements needed for these protein-protein interactions. 3) To dissect the stimulatory effects of MPV17 on mitochondrial biogenesis via metabolic, proteomic, and ultrastructure analyses.
Our studies of MPV17 have led to the realization that the metabolic conditions for cell growth have a major impact on mitochondrial function. We have identified nutrient growth regimes that stimulate mitochondrial protein synthesis while repressing protein synthesis in the cytosol. Therefore we predict that some mechanisms of stimulating mitochondrial capacity will repress cytosolic protein synthesis and thereby arrest cell growth and division.
Organisations
- The Francis Crick Institute (Fellow, Lead Research Organisation)
- Francis Crick Institute (Collaboration)
- UNIVERSITY OF EDINBURGH (Collaboration)
- University College London (Collaboration)
- Vall d'Hebron University Hospital (Collaboration)
- Newcastle University (Collaboration)
- Catholic University of the Sacred Heart (Collaboration)
- Medical Research Council (MRC) (Collaboration)
- The Lily Foundation (Collaboration)
- Helmholtz Association of German Research Centres (Collaboration)
Publications
Pearce S
(2013)
Mitochondrial diseases: translation matters.
in Molecular and cellular neurosciences
Malena A
(2016)
Mitochondrial quality control: Cell-type-dependent responses to pathological mutant mitochondrial DNA.
in Autophagy
Johnson M
(2014)
Amino Acid Starvation Has Opposite Effects on Mitochondrial and Cytosolic Protein Synthesis
in PLoS ONE
Frazier AE
(2017)
Reply: Genotype-phenotype correlation in ATAD3A deletions: not just of scientific relevance.
in Brain : a journal of neurology
Desai R
(2017)
ATAD3 gene cluster deletions cause cerebellar dysfunction associated with altered mitochondrial DNA and cholesterol metabolism.
in Brain : a journal of neurology
Dalla Rosa I
(2016)
MPV17 Loss Causes Deoxynucleotide Insufficiency and Slow DNA Replication in Mitochondria.
in PLoS genetics
Dalla Rosa I
(2014)
MPV17L2 is required for ribosome assembly in mitochondria.
in Nucleic acids research
Akman G
(2016)
Pathological ribonuclease H1 causes R-loop depletion and aberrant DNA segregation in mitochondria.
in Proceedings of the National Academy of Sciences of the United States of America
Related Projects
Project Reference | Relationship | Related To | Start | End | Award Value |
---|---|---|---|---|---|
MC_PC_13029/1 | 23/01/2013 | 30/08/2016 | £184,168 | ||
MC_PC_13029/2 | Transfer | MC_PC_13029/1 | 31/08/2016 | 31/01/2019 | £1,042,186 |
Description | Third scientific review of the safety and efficacy of methods to avoid mitochondrial disease through assisted conception: 2014 update |
Geographic Reach | National |
Policy Influence Type | Participation in a guidance/advisory committee |
Impact | UK is the first country to allow mitochondrial replacement therapy. While the method is not perfect, and thus there is room for improvement, it can help at preventing the transmission of mtDNA mutations. |
URL | https://www.hfea.gov.uk/ |
Description | Marie Curie |
Amount | € 310,000 (EUR) |
Organisation | European Commission |
Sector | Public |
Country | European Union (EU) |
Start | 01/2013 |
End | 01/2017 |
Title | New sequencing method |
Description | The new method is able to determine the identity of the embedded ribonucleotides incorporated in DNA. We have used the new method to study the ribonucleotide incorporation in mitochondrial DNA in health and disease state. |
Type Of Material | Technology assay or reagent |
Year Produced | 2017 |
Provided To Others? | Yes |
Impact | The method has allowed the identification of a new mtDNA abnormality, which we predict to be a feature of many disorders in which mitochondrial function is impaired |
Description | Elucidating the cellular metabolic alterations in mitochondrial dysfunction |
Organisation | Helmholtz Association of German Research Centres |
Department | Helmholtz Zentrum Munchen |
Country | Germany |
Sector | Academic/University |
PI Contribution | Metabolomics and proteomics analysis in model of mitochondrial dysfunction |
Collaborator Contribution | Tissues from a murine model of mitochondrial dysfunction |
Impact | To characterize pathways altered in mitochondrial disorders, which will represent attractive targets for drug treatment |
Start Year | 2015 |
Description | Elucidating the function of MPV17p |
Organisation | Francis Crick Institute |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | We isolated RNA from Mpv17 WT and KO mouse tissues |
Collaborator Contribution | Transcriptomic analysis of Mpv17 WT and KO mouse tissues |
Impact | Signalling pathways and compensatory mechanisms associated to the tissue-specific Mpv17 dysfunction |
Start Year | 2016 |
Description | Elucidating the function of new proteins involved in mitochondrial biogenesis |
Organisation | Catholic University of the Sacred Heart |
Country | Italy |
Sector | Academic/University |
PI Contribution | We are currently studying the cell lines with methods and antibodies developed in house |
Collaborator Contribution | The collaborators have provided patient-derived cell lines. |
Impact | Mitochondrial deficient phenotype linked to new functional aspects of mitochondrial proteins. Papers in high profile journal |
Start Year | 2014 |
Description | Elucidating the function of new proteins involved in mitochondrial biogenesis |
Organisation | Newcastle University |
Department | Mitochondrial Research Group |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | We are currently studying the cell lines with methods and antibodies developed in house |
Collaborator Contribution | The collaborators have provided patient-derived cell lines. |
Impact | Mitochondrial deficient phenotype linked to new functional aspects of mitochondrial proteins. Papers in high profile journal |
Start Year | 2014 |
Description | Elucidating the role of Mpv17 in nucleotide metabolism |
Organisation | Vall d'Hebron University Hospital |
Country | Spain |
Sector | Hospitals |
PI Contribution | Tissues and mitochondria from Wt and Mpv17 KO mice |
Collaborator Contribution | Analysis of mitochondrial subfractions |
Impact | Abstract for meetings. Consortium organization for the study of mitochondrial DNA depletion and deletions Syndromes. |
Start Year | 2018 |
Description | Manipulating mtDNA segregation |
Organisation | Francis Crick Institute |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Identification of small compounds that drive the wild-type mtDNA segregation |
Collaborator Contribution | Characterization of the pathways underpinning the wild-type mtDNA segregation |
Impact | The knowledge of the pathways necessary for the selection of mtDNA variants The identification of new small molecules that drive mtDNA segregation in patients derived fibroblasts. |
Start Year | 2013 |
Description | Manipulating the selection of mtDNA variants |
Organisation | Newcastle University |
Department | Wellcome Trust Centre for Mitochondrial Research |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Investigating the effects of a small molecule on the level of mutated mtDNA and mitochondrial respiration. |
Collaborator Contribution | Recruitment of patients and their clinical assessment and follow up |
Impact | To determine whether the compound that works in in vitro systems is also effective in vivo. |
Start Year | 2018 |
Description | Manipulating the selection of mtDNA variants |
Organisation | The Lily Foundation |
Country | United Kingdom |
Sector | Charity/Non Profit |
PI Contribution | Investigating the effects of a small molecule on the level of mutated mtDNA and mitochondrial respiration. |
Collaborator Contribution | Recruitment of patients and their clinical assessment and follow up |
Impact | To determine whether the compound that works in in vitro systems is also effective in vivo. |
Start Year | 2018 |
Description | Manipulating the selection of mtDNA variants |
Organisation | University College London |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Investigating the effects of a small molecule on the level of mutated mtDNA and mitochondrial respiration. |
Collaborator Contribution | Recruitment of patients and their clinical assessment and follow up |
Impact | To determine whether the compound that works in in vitro systems is also effective in vivo. |
Start Year | 2018 |
Description | Measurement of metabolites |
Organisation | University College London |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Tissues samples from WT and Mpv17 KO mice |
Collaborator Contribution | Determination of metabolites in several tissues |
Impact | The effect of mtDNA perturbation on cellular metabolism |
Start Year | 2018 |
Description | Metabolomics |
Organisation | Medical Research Council (MRC) |
Department | MRC National Institute for Medical Research (NIMR) |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Characterization of mitochondrial metabolism in cells growing under different nutrient conditions. Characterization of metabolites in in vitro and in vivo model of mitochondrial dysfunction. |
Collaborator Contribution | Metabolomic analysis in cancer cells. Metabolomic analysis in patients-derived fibroblasts and mouse models of mitochondrial disease. |
Impact | Changes in metabolite profile in cells growing under amino acid starvation. |
Start Year | 2013 |
Description | Molecular basis of mitochondrial disorders |
Organisation | University College London |
Department | Institute of Neurology |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Characterization of the biochemical and molecular phenotypes in patient-derived cells and tissues |
Collaborator Contribution | The partners have identified new genes likely causative of human disorders. They have provided cell lines and tissues from affected patients |
Impact | Changes in mitochondrial metabolism supportive of the functional role of the causative genes. Papers in high profile journal |
Start Year | 2016 |
Description | Molecular basis of mitochondrial myopathy |
Organisation | Newcastle University |
Department | Wellcome Trust Centre for Mitochondrial Research |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Muscle samples from WT and KO mice |
Collaborator Contribution | Histology and Immunohistochemistry |
Impact | Time course of muscle pathology in a murine model of a mtDNA related disoder |
Start Year | 2018 |
Description | Ribonucleotide incorporation in mtDNA |
Organisation | University of Edinburgh |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Purified mtDNA from mouse tissues and culture cells for sequencing analysis |
Collaborator Contribution | Sequencing of the mtDNA using a new approach developed by the collaborators (Emboriboseq) and analysis of the data |
Impact | Identification of the identity and distribution of the ribonucleotide incorporated in mtDNA of normal tissues and cells. Identification of a new mtDNA abnormality, aberrant ribonucleotide incorporation, in tissues of the Mpv17 KO mouse. Paper in journal of high profile (PMID:29106596) |
Start Year | 2016 |
Description | Mitochondrial Conferences; Seminar to Universities |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Other audiences |
Results and Impact | Invitation to King's College to give a seminar (2015). Invitation to Newcastle University to give a seminar ( 2014). |
Year(s) Of Engagement Activity | 2014,2015 |
Description | Nijmegen |
Form Of Engagement Activity | A formal working group, expert panel or dialogue |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | Marie Curie ITN graduate students, Supervisors, patients and patients' family met for two days to discuss research outcomes and outline future plans. Formal and informal discussions stimulated novel collaborations and created additional bonds among the students. Patients and their families felt supported and heard. |
Year(s) Of Engagement Activity | 2016 |
URL | http://www.itn-meet.org/ |