1
|
Messina M, Vaz FM, Rahman S. Mitochondrial membrane synthesis, remodelling and cellular trafficking. J Inherit Metab Dis 2024. [PMID: 38872485 DOI: 10.1002/jimd.12766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/14/2024] [Accepted: 05/21/2024] [Indexed: 06/15/2024]
Abstract
Mitochondria are dynamic cellular organelles with complex roles in metabolism and signalling. Primary mitochondrial disorders are a group of approximately 400 monogenic disorders arising from pathogenic genetic variants impacting mitochondrial structure, ultrastructure and/or function. Amongst these disorders, defects of complex lipid biosynthesis, especially of the unique mitochondrial membrane lipid cardiolipin, and membrane biology are an emerging group characterised by clinical heterogeneity, but with recurrent features including cardiomyopathy, encephalopathy, neurodegeneration, neuropathy and 3-methylglutaconic aciduria. This review discusses lipid synthesis in the mitochondrial membrane, the mitochondrial contact site and cristae organising system (MICOS), mitochondrial dynamics and trafficking, and the disorders associated with defects of each of these processes. We highlight overlapping functions of proteins involved in lipid biosynthesis and protein import into the mitochondria, pointing to an overarching coordination and synchronisation of mitochondrial functions. This review also focuses on membrane interactions between mitochondria and other organelles, namely the endoplasmic reticulum, peroxisomes, lysosomes and lipid droplets. We signpost disorders of these membrane interactions that may explain the observation of secondary mitochondrial dysfunction in heterogeneous pathological processes. Disruption of these organellar interactions ultimately impairs cellular homeostasis and organismal health, highlighting the central role of mitochondria in human health and disease.
Collapse
Affiliation(s)
- Martina Messina
- Mitochondrial Research Group, Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, London, UK
- Metabolic Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Frédéric M Vaz
- Department of Laboratory Medicine and Pediatrics, Laboratory Genetic Metabolic Diseases, Emma Children's Hospital, Amsterdam UMC Location University of Amsterdam, Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Inborn Errors of Metabolism, Amsterdam, The Netherlands
| | - Shamima Rahman
- Mitochondrial Research Group, Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, London, UK
- Metabolic Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| |
Collapse
|
2
|
Lewis LSC, Skiba NP, Hao Y, Bomze HM, Arshavsky VY, Cartoni R, Gospe SM. Compartmental Differences in the Retinal Ganglion Cell Mitochondrial Proteome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.07.593032. [PMID: 38766051 PMCID: PMC11100734 DOI: 10.1101/2024.05.07.593032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Among neurons, retinal ganglion cells (RGCs) are uniquely sensitive to mitochondrial dysfunction. The RGC is highly polarized, with a somatodendritic compartment in the inner retina and an axonal compartment projecting to targets in the brain. The drastically dissimilar functions of these compartments implies that mitochondria face different bioenergetic and other physiological demands. We hypothesized that compartmental differences in mitochondrial biology would be reflected by disparities in mitochondrial protein composition. Here, we describe a protocol to isolate intact mitochondria separately from mouse RGC somatodendritic and axonal compartments by immunoprecipitating labeled mitochondria from RGC MitoTag mice. Using mass spectrometry, 471 and 357 proteins were identified in RGC somatodendritic and axonal mitochondrial immunoprecipitates, respectively. We identified 10 mitochondrial proteins exclusively in the somatodendritic compartment and 19 enriched ≥2-fold there, while 3 proteins were exclusively identified and 18 enriched in the axonal compartment. Our observation of compartment-specific enrichment of mitochondrial proteins was validated through immunofluorescence analysis of the localization and relative abundance of superoxide dismutase ( SOD2 ), sideroflexin-3 ( SFXN3 ) and trifunctional enzyme subunit alpha ( HADHA ) in retina and optic nerve specimens. The identified compartmental differences in RGC mitochondrial composition may provide promising leads for uncovering physiologically relevant pathways amenable to therapeutic intervention for optic neuropathies.
Collapse
|
3
|
Nie J, Ma S, Zhang Y, Yu S, Yang J, Li A, Pei D. COPI Vesicle Disruption Inhibits Mineralization via mTORC1-Mediated Autophagy. Int J Mol Sci 2023; 25:339. [PMID: 38203512 PMCID: PMC10779376 DOI: 10.3390/ijms25010339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/21/2023] [Accepted: 12/22/2023] [Indexed: 01/12/2024] Open
Abstract
Bone mineralization is a sophisticated regulated process composed of crystalline calcium phosphate and collagen fibril. Autophagy, an evolutionarily conserved degradation system, whereby double-membrane vesicles deliver intracellular macromolecules and organelles to lysosomes for degradation, has recently been shown to play an essential role in mineralization. However, the formation of autophagosomes in mineralization remains to be determined. Here, we show that Coat Protein Complex I (COPI), responsible for Golgi-to-ER transport, plays a pivotal role in autophagosome formation in mineralization. COPI vesicles were increased after osteoinduction, and COPI vesicle disruption impaired osteogenesis. Mechanistically, COPI regulates autophagy activity via the mTOR complex 1 (mTORC1) pathway, a key regulator of autophagy. Inhibition of mTOR1 rescues the impaired osteogenesis by activating autophagy. Collectively, our study highlights the functional importance of COPI in mineralization and identifies COPI as a potential therapeutic target for treating bone-related diseases.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Dandan Pei
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi’an Jiaotong University, Xi’an 710004, China
| |
Collapse
|
4
|
Townsend LN, Clarke H, Maddison D, Jones KM, Amadio L, Jefferson A, Chughtai U, Bis DM, Züchner S, Allen ND, Van der Goes van Naters W, Peters OM, Smith GA. Cdk12 maintains the integrity of adult axons by suppressing actin remodeling. Cell Death Discov 2023; 9:348. [PMID: 37730761 PMCID: PMC10511712 DOI: 10.1038/s41420-023-01642-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 08/25/2023] [Accepted: 09/07/2023] [Indexed: 09/22/2023] Open
Abstract
The role of cyclin-dependent kinases (CDKs) that are ubiquitously expressed in the adult nervous system remains unclear. Cdk12 is enriched in terminally differentiated neurons where its conical role in the cell cycle progression is redundant. We find that in adult neurons Cdk12 acts a negative regulator of actin formation, mitochondrial dynamics and neuronal physiology. Cdk12 maintains the size of the axon at sites proximal to the cell body through the transcription of homeostatic enzymes in the 1-carbon by folate pathway which utilize the amino acid homocysteine. Loss of Cdk12 leads to elevated homocysteine and in turn leads to uncontrolled F-actin formation and axonal swelling. Actin remodeling further induces Drp1-dependent fission of mitochondria and the breakdown of axon-soma filtration barrier allowing soma restricted cargos to enter the axon. We demonstrate that Cdk12 is also an essential gene for long-term neuronal survival and loss of this gene causes age-dependent neurodegeneration. Hyperhomocysteinemia, actin changes, and mitochondrial fragmentation are associated with several neurodegenerative conditions such as Alzheimer's disease and we provide a candidate molecular pathway to link together such pathological events.
Collapse
Affiliation(s)
- L N Townsend
- School of Biosciences, Cardiff University, Cardiff, CF24 4HQ, UK
| | - H Clarke
- School of Medicine, Cardiff University, Cardiff, CF24 4HQ, UK
- UK Dementia Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK
| | - D Maddison
- School of Medicine, Cardiff University, Cardiff, CF24 4HQ, UK
- UK Dementia Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK
| | - K M Jones
- School of Biosciences, Cardiff University, Cardiff, CF24 4HQ, UK
| | - L Amadio
- School of Biosciences, Cardiff University, Cardiff, CF24 4HQ, UK
- School of Medicine, Cardiff University, Cardiff, CF24 4HQ, UK
- UK Dementia Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK
| | - A Jefferson
- School of Medicine, Cardiff University, Cardiff, CF24 4HQ, UK
- UK Dementia Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK
| | - U Chughtai
- School of Biosciences, Cardiff University, Cardiff, CF24 4HQ, UK
- School of Medicine, Cardiff University, Cardiff, CF24 4HQ, UK
- UK Dementia Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK
| | - D M Bis
- John P. Hussman Institute for Human Genomics, University of Miami, Miami, FL, USA
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Miami, FL, USA
| | - S Züchner
- John P. Hussman Institute for Human Genomics, University of Miami, Miami, FL, USA
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Miami, FL, USA
| | - N D Allen
- School of Biosciences, Cardiff University, Cardiff, CF24 4HQ, UK
| | | | - O M Peters
- School of Biosciences, Cardiff University, Cardiff, CF24 4HQ, UK
- UK Dementia Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK
| | - G A Smith
- School of Medicine, Cardiff University, Cardiff, CF24 4HQ, UK.
- UK Dementia Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK.
| |
Collapse
|