1
|
Borna NN, Kishita Y, Shimura M, Murayama K, Ohtake A, Okazaki Y. Identification of a novel MT-ND3 variant and restoring mitochondrial function by allotopic expression of MT-ND3 gene. Mitochondrion 2024; 76:101858. [PMID: 38437941 DOI: 10.1016/j.mito.2024.101858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 02/22/2024] [Accepted: 03/01/2024] [Indexed: 03/06/2024]
Abstract
Mitochondrial diseases are caused by nuclear, or mitochondrial DNA (mtDNA) variants and related co-factors. Here, we report a novel m.10197G > C variant in MT-ND3 in a patient, and two other patients with m.10191 T > C. MT-ND3 variants are known to cause Leigh syndrome or mitochondrial complex I deficiency. We performed the functional analyses of the novel m.10197G > C variant that significantly lowered MT-ND3 protein levels, causing complex I assembly and activity deficiency, and reduction of ATP synthesis. We adapted a previously described re-engineering technique of delivering mitochondrial genes into mitochondria through codon optimization for nuclear expression and translation by cytoplasmic ribosomes to rescue defects arising from the MT-ND3 variants. We constructed mitochondrial targeting sequences along with the codon-optimized MT-ND3 and imported them into the mitochondria. To achieve the goal, we imported codon-optimized MT-ND3 into mitochondria in three patients with m.10197G > C and m.10191 T > C missense variants in the MT-ND3. Nuclear expression of the MT-ND3 gene partially restored protein levels, complex I deficiency, and significant improvement of ATP production indicating a functional rescue of the mutant phenotype. The codon-optimized nuclear expression of mitochondrial protein and import inside the mitochondria can supplement the requirements for ATP in energy-deficient mitochondrial disease patients.
Collapse
Affiliation(s)
- Nurun Nahar Borna
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan; Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yoshihito Kishita
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan; Laboratory of Genome Sciences, Department of Life Science, Faculty of Science and Engineering, Kindai University, Higashiosaka, Osaka 577-8502, Japan
| | - Masaru Shimura
- Department of Metabolism, Chiba Children's Hospital, Midori-ku, Chiba 266-0007, Japan
| | - Kei Murayama
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan; Department of Pediatrics, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Akira Ohtake
- Department of Pediatrics & Clinical Genomics, Faculty of Medicine, Saitama Medical University, Moroyama, Saitama 350-0495, Japan; Center for Intractable Diseases, Saitama Medical University Hospital, Moroyama, Saitama 350-0495, Japan
| | - Yasushi Okazaki
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan; Laboratory for Comprehensive Genomic Analysis, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan.
| |
Collapse
|
2
|
Hu Z, Yang L, Zhang M, Tang H, Huang Y, Su Y, Ding Y, Li C, Wang M, Zhou Y, Zhang Q, Guo L, Wu Y, Wang Q, Liu N, Kang H, Wu Y, Yao D, Li Y, Ruan Z, Wang H, Bao F, Liu G, Wang J, Wang Y, Wang W, Lu G, Qin D, Pei D, Chan WY, Liu X. A novel protein CYTB-187AA encoded by the mitochondrial gene CYTB modulates mammalian early development. Cell Metab 2024:S1550-4131(24)00132-3. [PMID: 38703762 DOI: 10.1016/j.cmet.2024.04.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/10/2023] [Accepted: 04/16/2024] [Indexed: 05/06/2024]
Abstract
The mitochondrial genome transcribes 13 mRNAs coding for well-known proteins essential for oxidative phosphorylation. We demonstrate here that cytochrome b (CYTB), the only mitochondrial-DNA-encoded transcript among complex III, also encodes an unrecognized 187-amino-acid-long protein, CYTB-187AA, using the standard genetic code of cytosolic ribosomes rather than the mitochondrial genetic code. After validating the existence of this mtDNA-encoded protein arising from cytosolic translation (mPACT) using mass spectrometry and antibodies, we show that CYTB-187AA is mainly localized in the mitochondrial matrix and promotes the pluripotent state in primed-to-naive transition by interacting with solute carrier family 25 member 3 (SLC25A3) to modulate ATP production. We further generated a transgenic knockin mouse model of CYTB-187AA silencing and found that reduction of CYTB-187AA impairs females' fertility by decreasing the number of ovarian follicles. For the first time, we uncovered the novel mPACT pattern of a mitochondrial mRNA and demonstrated the physiological function of this 14th protein encoded by mtDNA.
Collapse
Affiliation(s)
- Zhijuan Hu
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China; Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong, SAR, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, China-New Zealand Joint Laboratory on Biomedicine and Health, CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Centre, Institute for Stem Cell and Regeneration, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China; University of Chinese Academy of Sciences, Beijing, China
| | - Liang Yang
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, China-New Zealand Joint Laboratory on Biomedicine and Health, CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Centre, Institute for Stem Cell and Regeneration, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Maolei Zhang
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, China-New Zealand Joint Laboratory on Biomedicine and Health, CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Centre, Institute for Stem Cell and Regeneration, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Haite Tang
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, China-New Zealand Joint Laboratory on Biomedicine and Health, CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Centre, Institute for Stem Cell and Regeneration, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Yile Huang
- Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong, SAR, China
| | - Yujie Su
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, China-New Zealand Joint Laboratory on Biomedicine and Health, CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Centre, Institute for Stem Cell and Regeneration, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yingzhe Ding
- Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong, SAR, China
| | - Chong Li
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, China-New Zealand Joint Laboratory on Biomedicine and Health, CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Centre, Institute for Stem Cell and Regeneration, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Mengfei Wang
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, China-New Zealand Joint Laboratory on Biomedicine and Health, CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Centre, Institute for Stem Cell and Regeneration, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yunhao Zhou
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, China-New Zealand Joint Laboratory on Biomedicine and Health, CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Centre, Institute for Stem Cell and Regeneration, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China; University of Chinese Academy of Sciences, Beijing, China
| | - Qing Zhang
- Proteomics and Metabolomics Core Facility, Guangzhou National Laboratory, Guangzhou, China
| | - Liman Guo
- Proteomics and Metabolomics Core Facility, Guangzhou National Laboratory, Guangzhou, China
| | - Yue Wu
- Proteomics and Metabolomics Core Facility, Guangzhou National Laboratory, Guangzhou, China
| | - Qianqian Wang
- State Key Laboratory of Medicinal Chemistry Biology, Nankai University, Tianjin, China
| | - Ning Liu
- State Key Laboratory of Medicinal Chemistry Biology, Nankai University, Tianjin, China
| | - Haoran Kang
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, China-New Zealand Joint Laboratory on Biomedicine and Health, CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Centre, Institute for Stem Cell and Regeneration, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Yi Wu
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, China-New Zealand Joint Laboratory on Biomedicine and Health, CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Centre, Institute for Stem Cell and Regeneration, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Deyang Yao
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, China-New Zealand Joint Laboratory on Biomedicine and Health, CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Centre, Institute for Stem Cell and Regeneration, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Yukun Li
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, China-New Zealand Joint Laboratory on Biomedicine and Health, CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Centre, Institute for Stem Cell and Regeneration, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China; University of Chinese Academy of Sciences, Beijing, China
| | - Zifeng Ruan
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, China-New Zealand Joint Laboratory on Biomedicine and Health, CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Centre, Institute for Stem Cell and Regeneration, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China; University of Chinese Academy of Sciences, Beijing, China
| | - Hao Wang
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, China-New Zealand Joint Laboratory on Biomedicine and Health, CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Centre, Institute for Stem Cell and Regeneration, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Feixiang Bao
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, China-New Zealand Joint Laboratory on Biomedicine and Health, CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Centre, Institute for Stem Cell and Regeneration, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Guopan Liu
- Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong, SAR, China
| | - Junwei Wang
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, China-New Zealand Joint Laboratory on Biomedicine and Health, CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Centre, Institute for Stem Cell and Regeneration, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Yaofeng Wang
- Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong, SAR, China
| | - Wuming Wang
- CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, CUHK-Jinan University Key Laboratory for Regenerative Medicine, Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, SAR, China
| | - Gang Lu
- CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, CUHK-Jinan University Key Laboratory for Regenerative Medicine, Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, SAR, China
| | - Dajiang Qin
- Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong, SAR, China; Key Laboratory of Biological Targeting Diagnosis, Therapy and Rehabilitation of Guangdong Higher Education Institutes, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Duanqing Pei
- Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong, SAR, China; Laboratory of Cell Fate Control, School of Life Sciences, Westlake University, Hangzhou, China
| | - Wai-Yee Chan
- CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, CUHK-Jinan University Key Laboratory for Regenerative Medicine, Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, SAR, China
| | - Xingguo Liu
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China; Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong, SAR, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, China-New Zealand Joint Laboratory on Biomedicine and Health, CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Centre, Institute for Stem Cell and Regeneration, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.
| |
Collapse
|
3
|
Del Dotto V, Musiani F, Baracca A, Solaini G. Variants in Human ATP Synthase Mitochondrial Genes: Biochemical Dysfunctions, Associated Diseases, and Therapies. Int J Mol Sci 2024; 25:2239. [PMID: 38396915 PMCID: PMC10889682 DOI: 10.3390/ijms25042239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/06/2024] [Accepted: 02/08/2024] [Indexed: 02/25/2024] Open
Abstract
Mitochondrial ATP synthase (Complex V) catalyzes the last step of oxidative phosphorylation and provides most of the energy (ATP) required by human cells. The mitochondrial genes MT-ATP6 and MT-ATP8 encode two subunits of the multi-subunit Complex V. Since the discovery of the first MT-ATP6 variant in the year 1990 as the cause of Neuropathy, Ataxia, and Retinitis Pigmentosa (NARP) syndrome, a large and continuously increasing number of inborn variants in the MT-ATP6 and MT-ATP8 genes have been identified as pathogenic. Variants in these genes correlate with various clinical phenotypes, which include several neurodegenerative and multisystemic disorders. In the present review, we report the pathogenic variants in mitochondrial ATP synthase genes and highlight the molecular mechanisms underlying ATP synthase deficiency that promote biochemical dysfunctions. We discuss the possible structural changes induced by the most common variants found in patients by considering the recent cryo-electron microscopy structure of human ATP synthase. Finally, we provide the state-of-the-art of all therapeutic proposals reported in the literature, including drug interventions targeting mitochondrial dysfunctions, allotopic gene expression- and nuclease-based strategies, and discuss their potential translation into clinical trials.
Collapse
Affiliation(s)
- Valentina Del Dotto
- Laboratory of Biochemistry and Mitochondrial Pathophysiology, Department of Biomedical and Neuromotor Sciences, University of Bologna, 40126 Bologna, Italy; (V.D.D.); (G.S.)
| | - Francesco Musiani
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology (FABIT), University of Bologna, 40127 Bologna, Italy;
| | - Alessandra Baracca
- Laboratory of Biochemistry and Mitochondrial Pathophysiology, Department of Biomedical and Neuromotor Sciences, University of Bologna, 40126 Bologna, Italy; (V.D.D.); (G.S.)
| | - Giancarlo Solaini
- Laboratory of Biochemistry and Mitochondrial Pathophysiology, Department of Biomedical and Neuromotor Sciences, University of Bologna, 40126 Bologna, Italy; (V.D.D.); (G.S.)
| |
Collapse
|
4
|
Nieto-Panqueva F, Rubalcava-Gracia D, Hamel PP, González-Halphen D. The constraints of allotopic expression. Mitochondrion 2023; 73:30-50. [PMID: 37739243 DOI: 10.1016/j.mito.2023.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 08/28/2023] [Accepted: 09/18/2023] [Indexed: 09/24/2023]
Abstract
Allotopic expression is the functional transfer of an organellar gene to the nucleus, followed by synthesis of the gene product in the cytosol and import into the appropriate organellar sub compartment. Here, we focus on mitochondrial genes encoding OXPHOS subunits that were naturally transferred to the nucleus, and critically review experimental evidence that claim their allotopic expression. We emphasize aspects that may have been overlooked before, i.e., when modifying a mitochondrial gene for allotopic expression━besides adapting the codon usage and including sequences encoding mitochondrial targeting signals━three additional constraints should be considered: (i) the average apparent free energy of membrane insertion (μΔGapp) of the transmembrane stretches (TMS) in proteins earmarked for the inner mitochondrial membrane, (ii) the final, functional topology attained by each membrane-bound OXPHOS subunit; and (iii) the defined mechanism by which the protein translocator TIM23 sorts cytosol-synthesized precursors. The mechanistic constraints imposed by TIM23 dictate the operation of two pathways through which alpha-helices in TMS are sorted, that eventually determine the final topology of membrane proteins. We used the biological hydrophobicity scale to assign an average apparent free energy of membrane insertion (μΔGapp) and a "traffic light" color code to all TMS of OXPHOS membrane proteins, thereby predicting which are more likely to be internalized into mitochondria if allotopically produced. We propose that the design of proteins for allotopic expression must make allowance for μΔGapp maximization of highly hydrophobic TMS in polypeptides whose corresponding genes have not been transferred to the nucleus in some organisms.
Collapse
Affiliation(s)
- Felipe Nieto-Panqueva
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Diana Rubalcava-Gracia
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico; Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Patrice P Hamel
- Department of Molecular Genetics and Department of Biological Chemistry and Pharmacology, Ohio State University, Columbus, OH, USA; Vellore Institute of Technology (VIT), School of BioScience and Technology, Vellore, Tamil Nadu, India
| | - Diego González-Halphen
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico.
| |
Collapse
|
5
|
Lear SK, Nunez JA, Shipman SL. A High-Throughput Colocalization Pipeline for Quantification of Mitochondrial Targeting across Different Protein Types. ACS Synth Biol 2023; 12:2498-2504. [PMID: 37506292 PMCID: PMC10561668 DOI: 10.1021/acssynbio.3c00349] [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] [Indexed: 07/30/2023]
Abstract
Efficient metabolic engineering and the development of mitochondrial therapeutics often rely upon the specific and strong import of foreign proteins into mitochondria. Fusing a protein to a mitochondria-bound signal peptide is a common method to localize proteins to mitochondria, but this strategy is not universally effective, with particular proteins empirically failing to localize. To help overcome this barrier, this work develops a generalizable and open-source framework to design proteins for mitochondrial import and quantify their specific localization. This Python-based pipeline quantitatively assesses the colocalization of different proteins previously used for precise genome editing in a high-throughput manner to reveal signal peptide-protein combinations that localize well in mitochondria.
Collapse
Affiliation(s)
- Sierra K Lear
- Gladstone Institute of Data Science and Biotechnology, San Francisco, California 94158, United States
- Graduate Program in Bioengineering, University of California, San Francisco and Berkeley, California 94720, United States
| | - Jose A Nunez
- Department of Mechanical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Seth L Shipman
- Gladstone Institute of Data Science and Biotechnology, San Francisco, California 94158, United States
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California 94143, United States
- Chan Zuckerberg Biohub - San Francisco, San Francisco, California 94158, United States
| |
Collapse
|
6
|
Lear SK, Nunez JA, Shipman SL. High-throughput colocalization pipeline quantifies efficacy of mitochondrial targeting signals across different protein types. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.03.535288. [PMID: 37066162 PMCID: PMC10103990 DOI: 10.1101/2023.04.03.535288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
Efficient metabolic engineering and the development of mitochondrial therapeutics often rely upon the specific and strong import of foreign proteins into mitochondria. Fusing a protein to a mitochondria-bound signal peptide is a common method to localize proteins to mitochondria, but this strategy is not universally effective with particular proteins empirically failing to localize. To help overcome this barrier, this work develops a generalizable and open-source framework to design proteins for mitochondrial import and quantify their specific localization. By using a Python-based pipeline to quantitatively assess the colocalization of different proteins previously used for precise genome editing in a high-throughput manner, we reveal signal peptide-protein combinations that localize well in mitochondria and, more broadly, general trends about the overall reliability of commonly used mitochondrial targeting signals.
Collapse
Affiliation(s)
- Sierra K Lear
- Gladstone Institute of Data Science and Biotechnology, San Francisco, CA, USA
- Graduate Program in Bioengineering, University of California, San Francisco and Berkeley, CA, USA
| | - Jose A Nunez
- Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA
| | - Seth L Shipman
- Gladstone Institute of Data Science and Biotechnology, San Francisco, CA, USA
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
- Chan Zuckerberg Biohub - San Francisco, San Francisco, CA, USA
| |
Collapse
|
7
|
Velmurugan S, Chou TH, Eastwood JD, Porciatti V, Liu Y, Hauswirth WW, Guy J, Yu H. Comparison of different gene-therapy methods to treat Leber hereditary optic neuropathy in a mouse model. Front Neurosci 2023; 17:1119724. [PMID: 37051151 PMCID: PMC10083341 DOI: 10.3389/fnins.2023.1119724] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 01/13/2023] [Indexed: 03/28/2023] Open
Abstract
IntroductionTherapies for Leber hereditary optic neuropathy (LHON), in common with all disorders caused by mutated mitochondrial DNA, are inadequate. We have developed two gene therapy strategies for the disease: mitochondrial-targeted and allotopic expressed and compared them in a mouse model of LHON.MethodsA LHON mouse model was generated by intravitreal injection of a mitochondrialtargeted Adeno-associated virus (AAV) carrying mutant human NADH dehydrogenase 4 gene (hND4/m.11778G>A) to induce retinal ganglion cell (RGC) degeneration and axon loss, the hallmark of the human disease. We then attempted to rescue those mice using a second intravitreal injection of either mitochondrial-targeted or allotopic expressed wildtype human ND4. The rescue of RGCs and their axons were assessed using serial pattern electroretinogram (PERG) and transmission electron microscopy.ResultsCompared to non-rescued LHON controls where PERG amplitude was much reduced, both strategies significantly preserved PERG amplitude over 15 months. However, the rescue effect was more marked with mitochondrial-targeted therapy than with allotopic therapy (p = 0.0128). Post-mortem analysis showed that mitochondrial-targeted human ND4 better preserved small axons that are preferentially lost in human LHON.ConclusionsThese results in a pre-clinical mouse model of LHON suggest that mitochondrially-targeted AAV gene therapy, compared to allotopic AAV gene therapy, is more efficient in rescuing the LHON phenotype.
Collapse
Affiliation(s)
- Sindhu Velmurugan
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Tsung-Han Chou
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Jeremy D. Eastwood
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Vittorio Porciatti
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
- *Correspondence: Vittorio Porciatti,
| | - Yuan Liu
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - William W. Hauswirth
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, FL, United States
| | - John Guy
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Hong Yu
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
- Hong Yu,
| |
Collapse
|
8
|
Falabella M, Minczuk M, Hanna MG, Viscomi C, Pitceathly RDS. Gene therapy for primary mitochondrial diseases: experimental advances and clinical challenges. Nat Rev Neurol 2022; 18:689-698. [PMID: 36257993 DOI: 10.1038/s41582-022-00715-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/25/2022] [Indexed: 11/09/2022]
Abstract
The variable clinical and biochemical manifestations of primary mitochondrial diseases (PMDs), and the complexity of mitochondrial genetics, have proven to be a substantial barrier to the development of effective disease-modifying therapies. Encouraging data from gene therapy trials in patients with Leber hereditary optic neuropathy and advances in DNA editing techniques have raised expectations that successful clinical transition of genetic therapies for PMDs is feasible. However, obstacles to the clinical application of genetic therapies in PMDs remain; the development of innovative, safe and effective genome editing technologies and vectors will be crucial to their future success and clinical approval. In this Perspective, we review progress towards the genetic treatment of nuclear and mitochondrial DNA-related PMDs. We discuss advances in mitochondrial DNA editing technologies alongside the unique challenges to targeting mitochondrial genomes. Last, we consider ongoing trials and regulatory requirements.
Collapse
Affiliation(s)
- Micol Falabella
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Michael G Hanna
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Queen Square Centre for Neuromuscular Diseases, The National Hospital for Neurology and Neurosurgery, London, UK
| | - Carlo Viscomi
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- CESNE - Center for the Study of Neurodegeneration, University of Padova, Padova, Italy
| | - Robert D S Pitceathly
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK.
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Queen Square Centre for Neuromuscular Diseases, The National Hospital for Neurology and Neurosurgery, London, UK.
| |
Collapse
|
9
|
The Mitochondrial Genome in Aging and Disease and the Future of Mitochondrial Therapeutics. Biomedicines 2022; 10:biomedicines10020490. [PMID: 35203698 PMCID: PMC8962324 DOI: 10.3390/biomedicines10020490] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/10/2022] [Accepted: 02/16/2022] [Indexed: 11/29/2022] Open
Abstract
Mitochondria are intracellular organelles that utilize nutrients to generate energy in the form of ATP by oxidative phosphorylation. Mitochondrial DNA (mtDNA) in humans is a 16,569 base pair double-stranded circular DNA that encodes for 13 vital proteins of the electron transport chain. Our understanding of the mitochondrial genome’s transcription, translation, and maintenance is still emerging, and human pathologies caused by mtDNA dysfunction are widely observed. Additionally, a correlation between declining mitochondrial DNA quality and copy number with organelle dysfunction in aging is well-documented in the literature. Despite tremendous advancements in nuclear gene-editing technologies and their value in translational avenues, our ability to edit mitochondrial DNA is still limited. In this review, we discuss the current therapeutic landscape in addressing the various pathologies that result from mtDNA mutations. We further evaluate existing gene therapy efforts, particularly allotopic expression and its potential to become an indispensable tool for restoring mitochondrial health in disease and aging.
Collapse
|
10
|
Zeviani M, Carelli V. Mitochondrial Retinopathies. Int J Mol Sci 2021; 23:210. [PMID: 35008635 PMCID: PMC8745158 DOI: 10.3390/ijms23010210] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/14/2021] [Accepted: 12/18/2021] [Indexed: 12/13/2022] Open
Abstract
The retina is an exquisite target for defects of oxidative phosphorylation (OXPHOS) associated with mitochondrial impairment. Retinal involvement occurs in two ways, retinal dystrophy (retinitis pigmentosa) and subacute or chronic optic atrophy, which are the most common clinical entities. Both can present as isolated or virtually exclusive conditions, or as part of more complex, frequently multisystem syndromes. In most cases, mutations of mtDNA have been found in association with mitochondrial retinopathy. The main genetic abnormalities of mtDNA include mutations associated with neurogenic muscle weakness, ataxia and retinitis pigmentosa (NARP) sometimes with earlier onset and increased severity (maternally inherited Leigh syndrome, MILS), single large-scale deletions determining Kearns-Sayre syndrome (KSS, of which retinal dystrophy is a cardinal symptom), and mutations, particularly in mtDNA-encoded ND genes, associated with Leber hereditary optic neuropathy (LHON). However, mutations in nuclear genes can also cause mitochondrial retinopathy, including autosomal recessive phenocopies of LHON, and slowly progressive optic atrophy caused by dominant or, more rarely, recessive, mutations in the fusion/mitochondrial shaping protein OPA1, encoded by a nuclear gene on chromosome 3q29.
Collapse
Affiliation(s)
- Massimo Zeviani
- Department of Neurosciences, The Clinical School, University of Padova, 35128 Padova, Italy
- Veneto Institute of Molecular Medicine, Via Orus 2, 35128 Padova, Italy
| | - Valerio Carelli
- Department of Biomedical and Neuromotor Sciences, University of Bologna, 40139 Bologna, Italy
- Programma di Neurogenetica, IRCCS Istituto delle Scienze Neurologiche di Bologna, Via Altura 6, 40139 Bologna, Italy
| |
Collapse
|
11
|
Prasuhn J, Brüggemann N. Gene Therapeutic Approaches for the Treatment of Mitochondrial Dysfunction in Parkinson's Disease. Genes (Basel) 2021; 12:genes12111840. [PMID: 34828446 PMCID: PMC8623067 DOI: 10.3390/genes12111840] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 11/18/2021] [Accepted: 11/19/2021] [Indexed: 12/21/2022] Open
Abstract
Background: Mitochondrial dysfunction has been identified as a pathophysiological hallmark of disease onset and progression in patients with Parkinsonian disorders. Besides the overall emergence of gene therapies in treating these patients, this highly relevant molecular concept has not yet been defined as a target for gene therapeutic approaches. Methods: This narrative review will discuss the experimental evidence suggesting mitochondrial dysfunction as a viable treatment target in patients with monogenic and idiopathic Parkinson’s disease. In addition, we will focus on general treatment strategies and crucial challenges which need to be overcome. Results: Our current understanding of mitochondrial biology in parkinsonian disorders opens up the avenue for viable treatment strategies in Parkinsonian disorders. Insights can be obtained from primary mitochondrial diseases. However, substantial knowledge gaps and unique challenges of mitochondria-targeted gene therapies need to be addressed to provide innovative treatments in the future. Conclusions: Mitochondria-targeted gene therapies are a potential strategy to improve an important primary disease mechanism in Parkinsonian disorders. However, further studies are needed to address the unique design challenges for mitochondria-targeted gene therapies.
Collapse
Affiliation(s)
- Jannik Prasuhn
- Institute of Neurogenetics, University of Lübeck, 23562 Lübeck, Germany;
- Department of Neurology, University Medical Center Schleswig-Holstein, Campus Lübeck, 23562 Lübeck, Germany
- Center for Brain, Behavior and Metabolism, University of Lübeck, 23562 Lübeck, Germany
| | - Norbert Brüggemann
- Institute of Neurogenetics, University of Lübeck, 23562 Lübeck, Germany;
- Department of Neurology, University Medical Center Schleswig-Holstein, Campus Lübeck, 23562 Lübeck, Germany
- Center for Brain, Behavior and Metabolism, University of Lübeck, 23562 Lübeck, Germany
- Correspondence:
| |
Collapse
|
12
|
Allotopic Expression of ATP6 in Mouse as a Transgenic Model of Mitochondrial Disease. Methods Mol Biol 2021. [PMID: 34080141 DOI: 10.1007/978-1-0716-1270-5_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/24/2023]
Abstract
Progress in animal modeling of polymorphisms and mutations in mitochondrial DNA (mtDNA) is not as developed as nuclear transgenesis due to a host of cellular and physiological distinctions. mtDNA mutation modeling is of critical importance as mutations in the mitochondrial genome give rise to a variety of pathological conditions and play a contributing role in many others. Nuclear localization and transcription of mtDNA genes followed by cytoplasmic translation and transport into mitochondria (allotopic expression, AE) provide an opportunity to create in vivo modeling of a targeted mutation in mitochondrial genes. Accordingly, such technology has been suggested as a strategy for gene replacement therapy in patients harboring mitochondrial DNA mutations. Here, we use our AE approach to transgenic mouse modeling of the pathogenic human T8993G mutation in mtATP6 as a case study for designing AE animal models.
Collapse
|
13
|
Peron C, Maresca A, Cavaliere A, Iannielli A, Broccoli V, Carelli V, Di Meo I, Tiranti V. Exploiting hiPSCs in Leber's Hereditary Optic Neuropathy (LHON): Present Achievements and Future Perspectives. Front Neurol 2021; 12:648916. [PMID: 34168607 PMCID: PMC8217617 DOI: 10.3389/fneur.2021.648916] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 04/26/2021] [Indexed: 01/19/2023] Open
Abstract
More than 30 years after discovering Leber's hereditary optic neuropathy (LHON) as the first maternally inherited disease associated with homoplasmic mtDNA mutations, we still struggle to achieve effective therapies. LHON is characterized by selective degeneration of retinal ganglion cells (RGCs) and is the most frequent mitochondrial disease, which leads young people to blindness, in particular males. Despite that causative mutations are present in all tissues, only a specific cell type is affected. Our deep understanding of the pathogenic mechanisms in LHON is hampered by the lack of appropriate models since investigations have been traditionally performed in non-neuronal cells. Effective in-vitro models of LHON are now emerging, casting promise to speed our understanding of pathophysiology and test therapeutic strategies to accelerate translation into clinic. We here review the potentials of these new models and their impact on the future of LHON patients.
Collapse
Affiliation(s)
- Camille Peron
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Alessandra Maresca
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | - Andrea Cavaliere
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Angelo Iannielli
- San Raffaele Scientific Institute, Milan, Italy.,National Research Council (CNR), Institute of Neuroscience, Milan, Italy
| | - Vania Broccoli
- San Raffaele Scientific Institute, Milan, Italy.,National Research Council (CNR), Institute of Neuroscience, Milan, Italy
| | - Valerio Carelli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy.,Department of Biomedical and Neuromotor Sciences-DIBINEM, University of Bologna, Bologna, Italy
| | - Ivano Di Meo
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Valeria Tiranti
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| |
Collapse
|
14
|
Stewart JB. Current progress with mammalian models of mitochondrial DNA disease. J Inherit Metab Dis 2021; 44:325-342. [PMID: 33099782 DOI: 10.1002/jimd.12324] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/19/2020] [Accepted: 10/21/2020] [Indexed: 12/16/2022]
Abstract
Mitochondrial disorders make up a large class of heritable diseases that cause a broad array of different human pathologies. They can affect many different organ systems, or display very specific tissue presentation, and can lead to illness either in childhood or later in life. While the over 1200 genes encoded in the nuclear DNA play an important role in human mitochondrial disease, it has been known for over 30 years that mutations of the mitochondria's own small, multicopy DNA chromosome (mtDNA) can lead to heritable human diseases. Unfortunately, animal mtDNA has resisted transgenic and directed genome editing technologies until quite recently. As such, animal models to aid in our understanding of these diseases, and to explore preclinical therapeutic research have been quite rare. This review will discuss the unusual properties of animal mitochondria that have hindered the generation of animal models. It will also discuss the existing mammalian models of human mtDNA disease, describe the methods employed in their generation, and will discuss recent advances in the targeting of DNA-manipulating enzymes to the mitochondria and how these may be employed to generate new models.
Collapse
Affiliation(s)
- James Bruce Stewart
- Max Planck Institute for Biology of Ageing, Cologne, Germany
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| |
Collapse
|
15
|
Amore G, Romagnoli M, Carbonelli M, Barboni P, Carelli V, La Morgia C. Therapeutic Options in Hereditary Optic Neuropathies. Drugs 2021; 81:57-86. [PMID: 33159657 PMCID: PMC7843467 DOI: 10.1007/s40265-020-01428-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Options for the effective treatment of hereditary optic neuropathies have been a long time coming. The successful launch of the antioxidant idebenone for Leber's Hereditary Optic Neuropathy (LHON), followed by its introduction into clinical practice across Europe, was an important step forward. Nevertheless, other options, especially for a variety of mitochondrial optic neuropathies such as dominant optic atrophy (DOA), are needed, and a number of pharmaceutical agents, acting on different molecular pathways, are currently under development. These include gene therapy, which has reached Phase III development for LHON, but is expected to be developed also for DOA, whilst most of the other agents (other antioxidants, anti-apoptotic drugs, activators of mitobiogenesis, etc.) are almost all at Phase II or at preclinical stage of research. Here, we review proposed target mechanisms, preclinical evidence, available clinical trials with primary endpoints and results, of a wide range of tested molecules, to give an overview of the field, also providing the landscape of future scenarios, including gene therapy, gene editing, and reproductive options to prevent transmission of mitochondrial DNA mutations.
Collapse
Affiliation(s)
- Giulia Amore
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
| | - Martina Romagnoli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Via Altura 3, 40139, Bologna, Italy
| | - Michele Carbonelli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Via Altura 3, 40139, Bologna, Italy
| | | | - Valerio Carelli
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Via Altura 3, 40139, Bologna, Italy
| | - Chiara La Morgia
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Via Altura 3, 40139, Bologna, Italy.
| |
Collapse
|
16
|
A Tribute to Dr. John R. Guy. J Neuroophthalmol 2020; 40:544-546. [PMID: 33289974 DOI: 10.1097/wno.0000000000001097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
17
|
The use of a MITO-Porter to deliver exogenous therapeutic RNA to a mitochondrial disease's cell with a A1555G mutation in the mitochondrial 12S rRNA gene results in an increase in mitochondrial respiratory activity. Mitochondrion 2020; 55:134-144. [PMID: 33035688 DOI: 10.1016/j.mito.2020.09.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 09/01/2020] [Accepted: 09/28/2020] [Indexed: 01/02/2023]
Abstract
We report on validating a mitochondrial gene therapeutic strategy using fibroblasts derived from patients with an A1555G point mutation in mitochondrial DNA coding 12S ribosomal RNA (rRNA (12S)). Wild-type rRNA (12S) as a therapeutic RNA was encapsulated in a mitochondrial targeting liposome, a MITO-Porter (rRNA-MITO-Porter), and an attempt was made to deliver the MITO-Porter to mitochondria of the diseased cells. It was confirmed that the rRNA-MITO-Porter treatment significantly decreased the ratio of the mutant rRNA content. Moreover, it was shown that the mitochondrial respiratory activities of the diseased cells were improved as the result of the mitochondrial transfection of the rRNA-MITO-Porter.
Collapse
|
18
|
Lewis CJ, Dixit B, Batiuk E, Hall CJ, O'Connor MS, Boominathan A. Codon optimization is an essential parameter for the efficient allotopic expression of mtDNA genes. Redox Biol 2020; 30:101429. [PMID: 31981894 PMCID: PMC6976934 DOI: 10.1016/j.redox.2020.101429] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 12/29/2019] [Accepted: 01/10/2020] [Indexed: 11/29/2022] Open
Abstract
Mutations in mitochondrial DNA can be inherited or occur de novo leading to several debilitating myopathies with no curative option and few or no effective treatments. Allotopic expression of recoded mitochondrial genes from the nucleus has potential as a gene therapy strategy for such conditions, however progress in this field has been hampered by technical challenges. Here we employed codon optimization as a tool to re-engineer the protein-coding genes of the human mitochondrial genome for robust, efficient expression from the nucleus. All 13 codon-optimized constructs exhibited substantially higher protein expression than minimally-recoded genes when expressed transiently, and steady-state mRNA levels for optimized gene constructs were 5-180 fold enriched over recoded versions in stably-selected wildtype cells. Eight of thirteen mitochondria-encoded oxidative phosphorylation (OxPhos) proteins maintained protein expression following stable selection, with mitochondrial localization of expression products. We also assessed the utility of this strategy in rescuing mitochondrial disease cell models and found the rescue capacity of allotopic expression constructs to be gene specific. Allotopic expression of codon optimized ATP8 in disease models could restore protein levels and respiratory function, however, rescue of the pathogenic phenotype for another gene, ND1 was only partially successful. These results imply that though codon-optimization alone is not sufficient for functional allotopic expression of most mitochondrial genes, it is an essential consideration in their design.
Collapse
Affiliation(s)
- Caitlin J Lewis
- Department of Mitochondrial Research, SENS Research Foundation, Mountain View, CA, 94041, USA
| | - Bhavna Dixit
- Department of Mitochondrial Research, SENS Research Foundation, Mountain View, CA, 94041, USA
| | - Elizabeth Batiuk
- Department of Mitochondrial Research, SENS Research Foundation, Mountain View, CA, 94041, USA
| | - Carter J Hall
- Department of Mitochondrial Research, SENS Research Foundation, Mountain View, CA, 94041, USA
| | - Matthew S O'Connor
- Department of Mitochondrial Research, SENS Research Foundation, Mountain View, CA, 94041, USA.
| | - Amutha Boominathan
- Department of Mitochondrial Research, SENS Research Foundation, Mountain View, CA, 94041, USA.
| |
Collapse
|
19
|
Artika IM. Allotopic expression of mitochondrial genes: Basic strategy and progress. Genes Dis 2019; 7:578-584. [PMID: 33335957 PMCID: PMC7729113 DOI: 10.1016/j.gendis.2019.08.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/23/2019] [Accepted: 08/01/2019] [Indexed: 12/11/2022] Open
Abstract
Allotopic expression of mitochondrial genes is a deliberate functional relocation of mitochondrial genes into the nucleus followed by import of the gene-encoded polypeptide from the cytoplasm into the mitochondria. For successful allotopic expression of a mitochondrial gene, several key aspects must be considered. These include the different codon dictionary used by the mitochondrial and nuclear genomes, different codon preferences between mitochondrial and nuclear-cytosolic translation systems, and the provision of an import signal to ensure that the newly translated protein in the cytosol is successfully imported into mitochondria. The allotopic expression strategy was first developed in yeast, a useful model organism for studying human and other eukaryotic cells. Currently, a number of mitochondrial genes have been successfully recoded and nuclearly expressed in yeast and human cells. In addition to its use in evolutionary and molecular biology studies, the allotopic expression strategy has been developed as a potential approach to treat mitochondrial genetic disorders. Substantial progress has been recently achieved, and the development of this technique for therapy of the mitochondrial disease Leber's hereditary optic neuropathy (LHON) has entered phase III clinical trials. However, a number of challenges remain to be overcome to accelerate the successful application of this technique. These include improvement of nuclear gene expression, import into mitochondria, processing, and functional integration of the allotopically expressed polypeptides into mitochondrial protein complexes. This review discusses the current basic strategy, progress, challenges, and prospects of the allotopic expression strategy for mitochondrial genes.
Collapse
Affiliation(s)
- I. Made Artika
- Department of Biochemistry, Faculty of Mathematics and Natural Sciences, Bogor Agricultural University, Darmaga Campus, Bogor 16680, Indonesia
- Eijkman Institute for Molecular Biology, Jalan Diponegoro 69, Jakarta, 10430, Indonesia
- Department of Biochemistry, Faculty of Mathematics and Natural Sciences, Bogor Agricultural University, Darmaga Campus, Bogor 16680, Indonesia
| |
Collapse
|
20
|
Miller TE, Henkels KM, Huddleston M, Salisbury R, Hussain SM, Sasaki AT, Cho KJ. Depletion of phosphatidylinositol 4-phosphate at the Golgi translocates K-Ras to mitochondria. J Cell Sci 2019; 132:jcs.231886. [PMID: 31331963 DOI: 10.1242/jcs.231886] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 07/12/2019] [Indexed: 01/05/2023] Open
Abstract
Ras proteins are small GTPases localized to the plasma membrane (PM), which regulate cellular proliferation, apoptosis and differentiation. After a series of post-translational modifications, H-Ras and N-Ras traffic to the PM from the Golgi via the classical exocytic pathway, but the exact mechanism of K-Ras trafficking to the PM from the ER is not fully characterized. ATP5G1 (also known as ATP5MC1) is one of the three proteins that comprise subunit c of the F 0 complex of the mitochondrial ATP synthase. In this study, we show that overexpression of the mitochondrial targeting sequence of ATP5G1 perturbs glucose metabolism, inhibits oncogenic K-Ras signaling, and redistributes phosphatidylserine (PtdSer) to mitochondria and other endomembranes, resulting in K-Ras translocation to mitochondria. Also, it depletes phosphatidylinositol 4-phosphate (PI4P) at the Golgi. Glucose supplementation restores PtdSer and K-Ras PM localization and PI4P at the Golgi. We further show that inhibition of the Golgi-localized PI4-kinases (PI4Ks) translocates K-Ras, and PtdSer to mitochondria and endomembranes, respectively. We conclude that PI4P at the Golgi regulates the PM localization of PtdSer and K-Ras.This article has an associated First Person interview with the first author of the paper.
Collapse
Affiliation(s)
- Taylor E Miller
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, OH 45435, USA
| | - Karen M Henkels
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, OH 45435, USA
| | - Mary Huddleston
- Human Signatures Branch, Human-Centered ISR Division, Airman Systems Directorate, 711 Human Performance Wing, Air Force Research Laboratory, Wright Patterson Air Force Base, OH 45433, USA
| | - Richard Salisbury
- Human Signatures Branch, Human-Centered ISR Division, Airman Systems Directorate, 711 Human Performance Wing, Air Force Research Laboratory, Wright Patterson Air Force Base, OH 45433, USA
| | - Saber M Hussain
- Human Signatures Branch, Human-Centered ISR Division, Airman Systems Directorate, 711 Human Performance Wing, Air Force Research Laboratory, Wright Patterson Air Force Base, OH 45433, USA
| | - Atsuo T Sasaki
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Kwang-Jin Cho
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, OH 45435, USA
| |
Collapse
|
21
|
Rubalcava-Gracia D, García-Rincón J, Pérez-Montfort R, Hamel PP, González-Halphen D. Key within-membrane residues and precursor dosage impact the allotopic expression of yeast subunit II of cytochrome c oxidase. Mol Biol Cell 2019; 30:2358-2366. [PMID: 31318312 PMCID: PMC6741066 DOI: 10.1091/mbc.e18-12-0788] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Experimentally relocating mitochondrial genes to the nucleus for functional expression (allotopic expression) is a challenging process. The high hydrophobicity of mitochondria-encoded proteins seems to be one of the main factors preventing this allotopic expression. We focused on subunit II of cytochrome c oxidase (Cox2) to study which modifications may enable or improve its allotopic expression in yeast. Cox2 can be imported from the cytosol into mitochondria in the presence of the W56R substitution, which decreases the protein hydrophobicity and allows partial respiratory rescue of a cox2-null strain. We show that the inclusion of a positive charge is more favorable than substitutions that only decrease the hydrophobicity. We also searched for other determinants enabling allotopic expression in yeast by examining the COX2 gene in organisms where it was transferred to the nucleus during evolution. We found that naturally occurring variations at within-membrane residues in the legume Glycine max Cox2 could enable yeast COX2 allotopic expression. We also evidence that directing high doses of allotopically synthesized Cox2 to mitochondria seems to be counterproductive because the subunit aggregates at the mitochondrial surface. Our findings are relevant to the design of allotopic expression strategies and contribute to the understanding of gene retention in organellar genomes.
Collapse
Affiliation(s)
- Diana Rubalcava-Gracia
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Juan García-Rincón
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Ruy Pérez-Montfort
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Patrice Paul Hamel
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Diego González-Halphen
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| |
Collapse
|
22
|
Abstract
The partitioning of genetic material between the nucleus and cytoplasmic (mitochondrial and plastid) genomes within eukaryotic cells necessitates coordinated integration between these genomic compartments, with important evolutionary and biomedical implications. Classic questions persist about the pervasive reduction of cytoplasmic genomes via a combination of gene loss, transfer and functional replacement - and yet why they are almost always retained in some minimal form. One striking consequence of cytonuclear integration is the existence of 'chimeric' enzyme complexes composed of subunits encoded in two different genomes. Advances in structural biology and comparative genomics are yielding important insights into the evolution of such complexes, including correlated sequence changes and recruitment of novel subunits. Thus, chimeric cytonuclear complexes provide a powerful window into the mechanisms of molecular co-evolution.
Collapse
|
23
|
Li H, Dai B, Fan J, Chen C, Nie X, Yin Z, Zhao Y, Zhang X, Wang DW. The Different Roles of miRNA-92a-2-5p and let-7b-5p in Mitochondrial Translation in db/db Mice. MOLECULAR THERAPY. NUCLEIC ACIDS 2019; 17:424-435. [PMID: 31319246 PMCID: PMC6637210 DOI: 10.1016/j.omtn.2019.06.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 06/11/2019] [Accepted: 06/12/2019] [Indexed: 12/21/2022]
Abstract
Excessive reactive oxygen species (ROS) generated in mitochondria is known to be a causal event in diabetic cardiomyopathy. Recent studies suggest that microRNAs (miRNAs) are able to translocate to mitochondria to modulate mitochondrial activities, but the roles of such miRNAs in diabetic cardiomyopathy remain unclear. We observed a marked reduction of mitochondrial gene cytochrome-b (mt-Cytb) in the heart of db/db mice compared with controls. Downregulation of mt-Cytb by small interfering RNA (siRNA) recaptured some key features of diabetes, including elevated ROS production. Microarray revealed that none of the miRNAs were upregulated, but 14 miRNAs were downregulated in mitochondria of db/db heart. miR-92a-2-5p and let-7b-5p targeted mt-Cytb and positively modulated mt-Cytb expression. Re-expression of miR-92a-2-5p and let-7b-5p into cardiomyocytes led to reduced ROS production. Furthermore, recombinant adeno-associated virus (rAAV)-mediated delivery of miR-92a-2-5p, but not let-7b-5p, was sufficient to rescue cardiac diastolic dysfunction in db/db heart. Let-7b-5p not only upregulated mt-Cytb in mitochondria, but also downregulated insulin receptor substrate 1 in cytosol and finally lead to no efficiency for improvement of diastolic dysfunction in db/db mice. Our findings demonstrate that reduced mitochondrial miRNAs contribute to impaired mitochondrial gene expression and elevated ROS production. Re-expression of miR-92a-2-5p enhances mitochondrial translation and reduces ROS production and lipid deposition, which finally rescues diabetic cardiomyopathy.
Collapse
Affiliation(s)
- Huaping Li
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan 430030, China.
| | - Beibei Dai
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan 430030, China
| | - Jiahui Fan
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan 430030, China
| | - Chen Chen
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan 430030, China
| | - Xiang Nie
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan 430030, China
| | - Zhongwei Yin
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan 430030, China
| | - Yanru Zhao
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan 430030, China
| | - Xudong Zhang
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan 430030, China
| | - Dao Wen Wang
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan 430030, China.
| |
Collapse
|
24
|
Markantone DM, Towheed A, Crain AT, Collins JM, Celotto AM, Palladino MJ. Protein coding mitochondrial-targeted RNAs rescue mitochondrial disease in vivo. Neurobiol Dis 2018; 117:203-210. [PMID: 29908326 DOI: 10.1016/j.nbd.2018.06.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 06/08/2018] [Accepted: 06/12/2018] [Indexed: 11/28/2022] Open
Abstract
Mitochondrial encephalomyopathies (MEs) result from mutations in mitochondrial genes critical to oxidative phosphorylation. Severe and untreatable ME results from mutations affecting each endogenous mitochondrial encoded gene, including all 13 established protein coding genes. Effective techniques to manipulate mitochondrial genome are limited and targeted mitochondrial protein expression is currently unavailable. Here we report the development of a mitochondrial-targeted RNA expression (mtTRES) vector capable of protein expression within mitochondria (mtTRESPro). We demonstrate that mtTRESPro expressed RNAs are targeted to mitochondria and are capable of being translated using EGFP encoded constructs in vivo. We additionally test mtTRESPro constructs encoding wild type ATP6 for their ability to rescue an established ATP61Drosophila model of ME. Genetic rescue is examined including tests with co-expression of mitochondrial targeted translational inhibitors TLI-NCL::ATP6 RNAs that function to reduce expression of the endogenous mutant protein. The data demonstrate allotopic RNA expression of mitochondrial targeted wild type ATP6 coding RNAs are sufficient to partially rescue a severe and established animal model of ME but only when combined with a method to inhibit mutant protein expression, which likely competes for incorporation into complex V.
Collapse
Affiliation(s)
- Desiree M Markantone
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Atif Towheed
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Aaron T Crain
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Jessica M Collins
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Alicia M Celotto
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Michael J Palladino
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
| |
Collapse
|
25
|
Rubalcava-Gracia D, Vázquez-Acevedo M, Funes S, Pérez-Martínez X, González-Halphen D. Mitochondrial versus nuclear gene expression and membrane protein assembly: the case of subunit 2 of yeast cytochrome c oxidase. Mol Biol Cell 2018; 29:820-833. [PMID: 29437907 PMCID: PMC5905295 DOI: 10.1091/mbc.e17-09-0560] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 01/12/2018] [Accepted: 02/01/2018] [Indexed: 12/24/2022] Open
Abstract
Deletion of the yeast mitochondrial gene COX2, encoding subunit 2 (mtCox2) of cytochrome c oxidase (CcO), results in a respiratory-incompetent Δcox2 strain. For a cytosol-synthesized Cox2 to restore respiratory growth, it must carry the W56R mutation (cCox2W56R). Nevertheless, only a fraction of cCox2W56R is matured in mitochondria, allowing ∼60% steady-state accumulation of CcO. This can be attributed either to the point mutation or to an inefficient biogenesis of cCox2W56R. We generated a strain expressing the mutant protein mtCox2W56R inside mitochondria which should follow the canonical biogenesis of mitochondria-encoded Cox2. This strain exhibited growth rates, CcO steady-state levels, and CcO activity similar to those of the wild type; therefore, the efficiency of Cox2 biogenesis is the limiting step for successful allotopic expression. Upon coexpression of cCox2W56R and mtCox2, each protein assembled into CcO independently from its genetic origin, resulting in a mixed population of CcO with most complexes containing the mtCox2 version. Notably, the presence of the mtCox2 enhances cCox2W56R incorporation. We provide proof of principle that an allotopically expressed Cox2 may complement a phenotype due to a mutant mitochondrial COX2 gene. These results are relevant to developing a rational design of genes for allotopic expression intended to treat human mitochondrial diseases.
Collapse
Affiliation(s)
- Diana Rubalcava-Gracia
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 Ciudad México, D. F., Mexico
| | - Miriam Vázquez-Acevedo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 Ciudad México, D. F., Mexico
| | - Soledad Funes
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 Ciudad México, D. F., Mexico
| | - Xochitl Pérez-Martínez
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 Ciudad México, D. F., Mexico
| | - Diego González-Halphen
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 Ciudad México, D. F., Mexico
| |
Collapse
|
26
|
Del Dotto V, Mishra P, Vidoni S, Fogazza M, Maresca A, Caporali L, McCaffery JM, Cappelletti M, Baruffini E, Lenaers G, Chan D, Rugolo M, Carelli V, Zanna C. OPA1 Isoforms in the Hierarchical Organization of Mitochondrial Functions. Cell Rep 2018. [PMID: 28636943 DOI: 10.1016/j.celrep.2017.05.073] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
OPA1 is a GTPase that controls mitochondrial fusion, cristae integrity, and mtDNA maintenance. In humans, eight isoforms are expressed as combinations of long and short forms, but it is unclear whether OPA1 functions are associated with specific isoforms and/or domains. To address this, we expressed each of the eight isoforms or different constructs of isoform 1 in Opa1-/- MEFs. We observed that any isoform could restore cristae structure, mtDNA abundance, and energetic efficiency independently of mitochondrial network morphology. Long forms supported mitochondrial fusion; short forms were better able to restore energetic efficiency. The complete rescue of mitochondrial network morphology required a balance of long and short forms of at least two isoforms, as shown by combinatorial isoform silencing and co-expression experiments. Thus, multiple OPA1 isoforms are required for mitochondrial dynamics, while any single isoform can support all other functions. These findings will be useful in designing gene therapies for patients with OPA1 haploinsufficiency.
Collapse
Affiliation(s)
- Valentina Del Dotto
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, 40126 Bologna, Italy; Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Unit of Neurology, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, 40139 Bologna, Italy
| | - Prashant Mishra
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Sara Vidoni
- Medical Research Council, Mitochondrial Biology Unit, Wellcome Trust, MRC Building, Cambridge CB2 0XY, UK
| | - Mario Fogazza
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, 40126 Bologna, Italy
| | - Alessandra Maresca
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, 40139 Bologna, Italy
| | - Leonardo Caporali
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, 40139 Bologna, Italy
| | - J Michael McCaffery
- Integrated Imaging Center, Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Martina Cappelletti
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, 40126 Bologna, Italy
| | - Enrico Baruffini
- Department of Chemical Science, Life and Environmental Sustainability, University of Parma, 43124 Parma, Italy
| | - Guy Lenaers
- PREMMi, CNRS UMR6214, INSERM U1083, Université d'Angers, 49933 Angers Cedex 9, France
| | - David Chan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Michela Rugolo
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, 40126 Bologna, Italy.
| | - Valerio Carelli
- Unit of Neurology, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, 40139 Bologna, Italy; IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, 40139 Bologna, Italy.
| | - Claudia Zanna
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, 40126 Bologna, Italy.
| |
Collapse
|
27
|
Chin RM, Panavas T, Brown JM, Johnson KK. Optimized Mitochondrial Targeting of Proteins Encoded by Modified mRNAs Rescues Cells Harboring Mutations in mtATP6. Cell Rep 2018. [DOI: 10.1016/j.celrep.2018.02.059] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
|
28
|
Szafranski P. Intercompartmental Piecewise Gene Transfer. Genes (Basel) 2017; 8:genes8100260. [PMID: 28984842 PMCID: PMC5664110 DOI: 10.3390/genes8100260] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 09/25/2017] [Accepted: 09/28/2017] [Indexed: 11/16/2022] Open
Abstract
Gene relocation from the residual genomes of organelles to the nuclear genome still continues, although as a scaled down evolutionary phenomenon, limited in occurrence mostly to protists (sensu lato) and land plants. During this process, the structural integrity of transferred genes is usually preserved. However, the relocation of mitochondrial genes that code for respiratory chain and ribosomal proteins is sometimes associated with their fragmentation into two complementary genes. Herein, this review compiles cases of piecewise gene transfer from the mitochondria to the nucleus, and discusses hypothesized mechanistic links between the fission and relocation of those genes.
Collapse
Affiliation(s)
- Przemyslaw Szafranski
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
| |
Collapse
|
29
|
Guy J, Feuer WJ, Davis JL, Porciatti V, Gonzalez PJ, Koilkonda RD, Yuan H, Hauswirth WW, Lam BL. Gene Therapy for Leber Hereditary Optic Neuropathy: Low- and Medium-Dose Visual Results. Ophthalmology 2017. [PMID: 28647203 DOI: 10.1016/j.ophtha.2017.05.016] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To determine the effects of AAV2(Y444,500,730F)-P1ND4v2 in patients with Leber hereditary optic neuropathy (LHON). DESIGN Prospective open-label, unilateral single-dose, intravitreal injection of AAV2(Y444,500,730F)-P1ND4v2 per participant. PARTICIPANTS Fourteen patients with visual loss and mutated G11778A mitochondrial DNA. METHODS Intravitreal injection with the gene therapy vector AAV2(Y444,500,730F)-P1ND4v2 into 1 eye. Six participants with chronic bilateral visual loss lasting more than 12 months (group 1), 6 participants with bilateral visual loss lasting less than 12 months (group 2), and 2 participants with unilateral visual loss (group 3) were treated. Nine patients had at least 12 months of follow-up. Clinical testing included visual acuity, visual fields, optical coherence tomography, pattern electroretinography, and neuro-ophthalmic examinations. Generalized estimating equation methods were used for longitudinal analyses. MAIN OUTCOME MEASURE Loss of visual acuity. RESULTS For groups 1 and 2, month 12 average acuity improvements with treatment relative to baseline were 0.24 logarithm of the minimum angle of resolution (logMAR). Fellow eyes had a 0.09-logMAR improvement. A post hoc comparison found that at month 12, the difference between study eye minus fellow eye improvement in group 2 patients of 0.53 logMAR was greater than that observed in our prior acute natural history patients of 0.21 logMAR (P = 0.053). At month 18, the difference between study eye minus fellow eye improvement in our acute group 2 gene therapy patients of 0.96 was more than that observed in our prior acute natural history patients (0.17 logMAR; P < 0.001). Two patients demonstrated asymptomatic uveitis that resolved without treatment. Optical coherence tomography of treated eyes showed an average temporal retinal nerve fiber layer thickness of 54 μm before injection and 55 μm at month 12. For fellow eyes before injection, it was 56 μm, decreasing to 50 μm at month 12 (P = 0.013). Generalized estimating equations suggested that PERG amplitudes worsened more in treated eyes than in fellow eyes by approximately 0.05 μV (P = 0.009 exchangeable). No difference between eyes in outcomes of other visual function measures was evident. CONCLUSIONS Allotopic gene therapy for LHON at low and medium doses seems to be safe and does not damage the temporal retinal nerve fiber layer, opening the door next for testing of the high dose.
Collapse
Affiliation(s)
- John Guy
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida.
| | - William J Feuer
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Janet L Davis
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Vittorio Porciatti
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Phillip J Gonzalez
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Rajeshwari D Koilkonda
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Huijun Yuan
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - William W Hauswirth
- Department of Ophthalmology University of Florida College of Medicine, Gainesville, Florida
| | - Byron L Lam
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| |
Collapse
|
30
|
Reid CA, Boye SL, Hauswirth WW, Lipinski DM. miRNA-mediated post-transcriptional silencing of transgenes leads to increased adeno-associated viral vector yield and targeting specificity. Gene Ther 2017; 24:462-469. [DOI: 10.1038/gt.2017.50] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 06/05/2017] [Accepted: 06/08/2017] [Indexed: 12/21/2022]
|
31
|
Bi R, Logan I, Yao YG. Leber Hereditary Optic Neuropathy: A Mitochondrial Disease Unique in Many Ways. Handb Exp Pharmacol 2017; 240:309-336. [PMID: 27787713 DOI: 10.1007/164_2016_1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Leber hereditary optic neuropathy (LHON) was the first mitochondrial disease to be identified as being caused by mutations in the mitochondrial DNA (mtDNA). This disease has been studied extensively in the past two decades, particularly in Brazilian, Chinese and European populations; and many primary mutations have been reported. However, the disease is enigmatic with many unique features, and there still are several important questions to be resolved. The incomplete penetrance, the male-biased disease expression and the prevalence in young adults all defy a proper explanation. It has been reported that the development of LHON is affected by the interaction between mtDNA mutations, mtDNA haplogroup background, nuclear genes, environmental factors and epigenetics. Furthermore, with the help of new animal models for LHON that have been created in recent years, we are continuing to learn more about the mechanism of this disease. The stage has now been reached at which there is a good understanding of both the genetic basis of the disease and its epidemiology, but just how the blindness that follows from the death of cells in the optic nerve can be prevented remains to be a pharmacological challenge. In this chapter, we summarize the progress that has been made in various recent studies on LHON, focusing on the molecular pathogenic mechanisms, clinical features, biochemical effects, the pharmacology and its treatment.
Collapse
Affiliation(s)
- Rui Bi
- Division of Medical Genetics & Evolutionary Medicine, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | | | - Yong-Gang Yao
- Division of Medical Genetics & Evolutionary Medicine, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.
| |
Collapse
|
32
|
Abstract
The report in 1988 that Leber Hereditary Optic Neuropathy (LHON) was the product of mitochondrial DNA (mtDNA) mutations provided the first demonstration of the clinical relevance of inherited mtDNA variation. From LHON studies, the medical importance was demonstrated for the mtDNA showing its coding for the most important energy genes, its maternal inheritance, its high mutation rate, its presence in hundreds to thousands of copies per cell, its quantitatively segregation of biallelic genotypes during both mitosis and meiosis, its preferential effect on the most energetic tissues including the eye and brain, its wide range of functional polymorphisms that predispose to common diseases, and its accumulation of mutations within somatic tissues providing the aging clock. These features of mtDNA genetics, in combination with the genetics of the 1-2000 nuclear DNA (nDNA) coded mitochondrial genes, is not only explaining the genetics of LHON but also providing a model for understanding the complexity of many common diseases. With the maturation of LHON biology and genetics, novel animal models for complex disease have been developed and new therapeutic targets and strategies envisioned, both pharmacological and genetic. Multiple somatic gene therapy approaches are being developed for LHON which are applicable to other mtDNA diseases. Moreover, the unique cytoplasmic genetics of the mtDNA has permitted the first successful human germline gene therapy via spindle nDNA transfer from mtDNA mutant oocytes to enucleated normal mtDNA oocytes. Such LHON lessons are actively being applied to common ophthalmological diseases like glaucoma and neurological diseases like Parkinsonism.
Collapse
|
33
|
Pereira CV, Moraes CT. Current strategies towards therapeutic manipulation of mtDNA heteroplasmy. Front Biosci (Landmark Ed) 2017; 22:991-1010. [PMID: 27814659 DOI: 10.2741/4529] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Mitochondrial disease is a multifactorial disorder involving both nuclear and mitochondrial genomes. Over the past 20 years, great progress was achieved in the field of gene editing which raised the possibility of partial or complete elimination of mutant mtDNA that causes disease phenotypes. Each cell contains thousands of copies of mtDNA which can be either wild-type (WT) or mutant, a condition called heteroplasmy. As there are multiple copies of mtDNA inside a cell, the percentage of mutant mtDNA can vary and a directional shift in the heteroplasmy ratio towards an increase of WT mtDNA copies would have therapeutic value. Gene editing tools have been adapted to translocate to mitochondria and were able to change heteroplasmy in a predictable manner. These include mitochondrial targeted restriction endonucleases, Zinc-finger nucleases, and TAL-effector nucleases. These procedures could also be adapted to reduce the levels of mutant mtDNA in embryos, offering an option to the controversial mitochondrial replacement techniques during in vitro fertilization. The current strategies to induce heteroplasmy shift of mtDNA and its implications will be comprehensively discussed.
Collapse
Affiliation(s)
- Claudia V Pereira
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Carlos T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA,
| |
Collapse
|
34
|
Björkholm P, Ernst AM, Hagström E, Andersson SGE. Why mitochondria need a genome revisited. FEBS Lett 2016; 591:65-75. [PMID: 27928819 DOI: 10.1002/1873-3468.12510] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 11/15/2016] [Accepted: 11/21/2016] [Indexed: 01/13/2023]
Abstract
In this paper, we experimentally address the debate about why functional transfer of mitochondrial genes to the nucleus has been halted in some organismal groups and why cytosolic expression of mitochondrial proteins has proven remarkably difficult. By expressing all 13 human mitochondrial-encoded genes with strong mitochondrial-targeting sequences in the cytosol of human cells, we show that all proteins, except ATP8, are transported to the endoplasmic reticulum (ER). These results confirm and extend previous findings based on three mitochondrial genes lacking mitochondrial-targeting sequences that also were relocated to the ER during cytosolic expression. We conclude that subcellular protein targeting constitutes a major barrier to functional transfer of mitochondrial genes to the nuclear genome.
Collapse
Affiliation(s)
- Patrik Björkholm
- Department of Molecular Evolution, Cell and Molecular Biology, Uppsala University, Sweden
| | - Andreas M Ernst
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Erik Hagström
- Department of Molecular Evolution, Cell and Molecular Biology, Uppsala University, Sweden
| | - Siv G E Andersson
- Department of Molecular Evolution, Cell and Molecular Biology, Uppsala University, Sweden
| |
Collapse
|
35
|
Boominathan A, Vanhoozer S, Basisty N, Powers K, Crampton AL, Wang X, Friedricks N, Schilling B, Brand MD, O'Connor MS. Stable nuclear expression of ATP8 and ATP6 genes rescues a mtDNA Complex V null mutant. Nucleic Acids Res 2016; 44:9342-9357. [PMID: 27596602 PMCID: PMC5100594 DOI: 10.1093/nar/gkw756] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 08/15/2016] [Accepted: 08/17/2016] [Indexed: 12/29/2022] Open
Abstract
We explore the possibility of re-engineering mitochondrial genes and expressing them from the nucleus as an approach to rescue defects arising from mitochondrial DNA mutations. We have used a patient cybrid cell line with a single point mutation in the overlap region of the ATP8 and ATP6 genes of the human mitochondrial genome. These cells are null for the ATP8 protein, have significantly lowered ATP6 protein levels and no Complex V function. Nuclear expression of only the ATP8 gene with the ATP5G1 mitochondrial targeting sequence appended restored viability on Krebs cycle substrates and ATP synthesis capabilities but, failed to restore ATP hydrolysis and was insensitive to various inhibitors of oxidative phosphorylation. Co-expressing both ATP8 and ATP6 genes under similar conditions resulted in stable protein expression leading to successful integration into Complex V of the oxidative phosphorylation machinery. Tests for ATP hydrolysis / synthesis, oxygen consumption, glycolytic metabolism and viability all indicate a significant functional rescue of the mutant phenotype (including re-assembly of Complex V) following stable co-expression of ATP8 and ATP6 Thus, we report the stable allotopic expression, import and function of two mitochondria encoded genes, ATP8 and ATP6, resulting in simultaneous rescue of the loss of both mitochondrial proteins.
Collapse
Affiliation(s)
| | - Shon Vanhoozer
- SENS Research Foundation Research Center, Mountain View, CA 94041, USA
| | - Nathan Basisty
- Keck School of Medicine of USC, Los Angeles, CA 90033, USA
| | - Kathleen Powers
- SENS Research Foundation Research Center, Mountain View, CA 94041, USA
| | | | - Xiaobin Wang
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Natalie Friedricks
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | | | - Martin D Brand
- Keck School of Medicine of USC, Los Angeles, CA 90033, USA
| | | |
Collapse
|
36
|
Gueven N, Nadikudi M, Daniel A, Chhetri J. Targeting mitochondrial function to treat optic neuropathy. Mitochondrion 2016; 36:7-14. [PMID: 27476756 DOI: 10.1016/j.mito.2016.07.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 07/25/2016] [Accepted: 07/26/2016] [Indexed: 01/03/2023]
Abstract
Many reports have illustrated a tight connection between vision and mitochondrial function. Not only are most mitochondrial diseases associated with some form of vision impairment, many ophthalmological disorders such as glaucoma, age-related macular degeneration and diabetic retinopathy also show signs of mitochondrial dysfunction. Despite a vast amount of evidence, vision loss is still only treated symptomatically, which is only partially a consequence of resistance to acknowledge that mitochondria could be the common denominator and hence a promising therapeutic target. More importantly, clinical support of this concept is only emerging. Moreover, only a few drug candidates and treatment strategies are in development or approved that selectively aim to restore mitochondrial function. This review rationalizes the currently developed therapeutic approaches that target mitochondrial function by discussing their proposed mode(s) of action and provides an overview on their development status with regards to optic neuropathies.
Collapse
Affiliation(s)
- Nuri Gueven
- Pharmacy, School of Medicine, University of Tasmania, Hobart, TAS, Australia.
| | - Monila Nadikudi
- Pharmacy, School of Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Abraham Daniel
- Pharmacy, School of Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Jamuna Chhetri
- Pharmacy, School of Medicine, University of Tasmania, Hobart, TAS, Australia
| |
Collapse
|
37
|
Feuer WJ, Schiffman JC, Davis JL, Porciatti V, Gonzalez P, Koilkonda RD, Yuan H, Lalwani A, Lam BL, Guy J. Gene Therapy for Leber Hereditary Optic Neuropathy: Initial Results. Ophthalmology 2015; 123:558-70. [PMID: 26606867 DOI: 10.1016/j.ophtha.2015.10.025] [Citation(s) in RCA: 174] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 10/13/2015] [Accepted: 10/13/2015] [Indexed: 01/01/2023] Open
Abstract
PURPOSE Leber hereditary optic neuropathy (LHON) is a disorder characterized by severe and rapidly progressive visual loss when caused by a mutation in the mitochondrial gene encoding NADH:ubiquinone oxidoreductase subunit 4 (ND4). We have initiated a gene therapy trial to determine the safety and tolerability of escalated doses of an adeno-associated virus vector (AAV) expressing a normal ND4 complementary DNA in patients with a G to A mutation at nucleotide 11778 of the mitochondrial genome. DESIGN In this prospective open-label trial (NCT02161380), the study drug (self-complementary AAV [scAAV]2(Y444,500,730F)-P1ND4v2) was intravitreally injected unilaterally into the eyes of 5 blind participants with G11778A LHON. Four participants with visual loss for more than 12 months were treated. The fifth participant had visual loss for less than 12 months. The first 3 participants were treated at the low dose of vector (5 × 10(9) vg), and the fourth participant was treated at the medium dose (2.46 × 10(10) vg). The fifth participant with visual loss for less than 12 months received the low dose. Treated participants were followed for 90 to 180 days and underwent ocular and systemic safety assessments along with visual structure and function examinations. PARTICIPANTS Five legally blind patients with G11778A LHON. MAIN OUTCOME MEASURES Loss of visual acuity. RESULTS Visual acuity as measured by the Early Treatment Diabetic Retinopathy Study (ETDRS) eye chart remained unchanged from baseline to 3 months in the first 3 participants. For 2 participants with 90-day follow-up, acuity increased from hand movements to 7 letters in 1 and by 15 letters in 1, representing an improvement equivalent to 3 lines. No one lost vision, and no serious adverse events were observed. Minor adverse events included a transient increase of intraocular pressure (IOP), exposure keratitis, subconjunctival hemorrhage, a sore throat, and a transient increase in neutralizing antibodies (NAbs) against AAV2 in 1 participant. All blood samples were negative for vector DNA. CONCLUSIONS No serious safety problems were observed in the first 5 participants enrolled in this phase I trial of virus-based gene transfer in this mitochondrial disorder. Additional study follow-up of these and additional participants planned for the next 4 years is needed to confirm these preliminary observations.
Collapse
Affiliation(s)
- William J Feuer
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Joyce C Schiffman
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Janet L Davis
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Vittorio Porciatti
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Phillip Gonzalez
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Rajeshwari D Koilkonda
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Huijun Yuan
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Anil Lalwani
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Byron L Lam
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - John Guy
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida.
| |
Collapse
|
38
|
Tischner C, Wenz T. Keep the fire burning: Current avenues in the quest of treating mitochondrial disorders. Mitochondrion 2015; 24:32-49. [DOI: 10.1016/j.mito.2015.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 06/18/2015] [Accepted: 06/24/2015] [Indexed: 12/18/2022]
|
39
|
Abstract
Mitochondria are energy-producing organelles in eukaryotic cells considered to be of bacterial origin. The mitochondrial genome has evolved under selection for minimization of gene content, yet it is not known why not all mitochondrial genes have been transferred to the nuclear genome. Here, we predict that hydrophobic membrane proteins encoded by the mitochondrial genomes would be recognized by the signal recognition particle and targeted to the endoplasmic reticulum if they were nuclear-encoded and translated in the cytoplasm. Expression of the mitochondrially encoded proteins Cytochrome oxidase subunit 1, Apocytochrome b, and ATP synthase subunit 6 in the cytoplasm of HeLa cells confirms export to the endoplasmic reticulum. To examine the extent to which the mitochondrial proteome is driven by selective constraints within the eukaryotic cell, we investigated the occurrence of mitochondrial protein domains in bacteria and eukaryotes. The accessory protein domains of the oxidative phosphorylation system are unique to mitochondria, indicating the evolution of new protein folds. Most of the identified domains in the accessory proteins of the ribosome are also found in eukaryotic proteins of other functions and locations. Overall, one-third of the protein domains identified in mitochondrial proteins are only rarely found in bacteria. We conclude that the mitochondrial genome has been maintained to ensure the correct localization of highly hydrophobic membrane proteins. Taken together, the results suggest that selective constraints on the eukaryotic cell have played a major role in modulating the evolution of the mitochondrial genome and proteome.
Collapse
|
40
|
Mitochondrial DNA Haplogroup A Decreases the Risk of Drug Addiction but Conversely Increases the Risk of HIV-1 Infection in Chinese Addicts. Mol Neurobiol 2015; 53:3873-3881. [PMID: 26162319 DOI: 10.1007/s12035-015-9323-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 06/24/2015] [Indexed: 01/19/2023]
Abstract
Drug addiction is one of the most serious social problems in the world today and addicts are always at a high risk of acquiring HIV infection. Mitochondrial impairment has been reported in both drug addicts and in HIV patients undergoing treatment. In this study, we aimed to investigate whether mitochondrial DNA (mtDNA) haplogroup could affect the risk of drug addiction and HIV-1 infection in Chinese. We analyzed mtDNA sequence variations of 577 Chinese intravenous drug addicts (289 with HIV-1 infection and 288 without) and compared with 2 control populations (n = 362 and n = 850). We quantified the viral load in HIV-1-infected patients with and without haplogroup A status and investigated the potential effect of haplogroup A defining variants m.4824A > G and m.8794C > T on the cellular reactive oxygen species (ROS) levels by using an allotopic expression assay. mtDNA haplogroup A had a protective effect against drug addiction but appeared to confer an increased risk of HIV infection in addicts. HIV-1-infected addicts with haplogroup A had a trend for a higher viral load, although the mean viral load was similar between carriers of haplogroup A and those with other haplogroup. Hela cells overexpressing allele m.8794 T showed significantly decreased ROS levels as compared to cells with the allele m.8794C (P = 0.03). Our results suggested that mtDNA haplogroup A might protect against drug addiction but increase the risk of HIV-1 infection. The contradictory role of haplogroup A might be caused by an alteration in mitochondrial function due to a particular mtDNA ancestral variant.
Collapse
|
41
|
Cannon MV, Irwin MH, Pinkert CA. Mitochondrially-Imported RNA in Drug Discovery. Drug Dev Res 2015; 76:61-71. [DOI: 10.1002/ddr.21241] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 12/14/2014] [Indexed: 12/15/2022]
Affiliation(s)
| | | | - Carl A. Pinkert
- Department of Pathobiology; Auburn University; Auburn AL USA
- Department of Biology; The University of Alabama; Tuscaloosa AL USA
| |
Collapse
|
42
|
Nuclear expression of mitochondrial ND4 leads to the protein assembling in complex I and prevents optic atrophy and visual loss. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2015; 2:15003. [PMID: 26029714 PMCID: PMC4444999 DOI: 10.1038/mtm.2015.3] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 01/05/2015] [Accepted: 01/09/2015] [Indexed: 12/13/2022]
Abstract
Leber hereditary optic neuropathy is due to mitochondrial DNA mutations; in ~70% of all cases, a point mutation in the mitochondrial NADH dehydrogenase subunit 4, ND4, gene leads to central vision loss. We optimized allotopic expression (nuclear transcription of a gene that is normally transcribed inside the mitochondria) aimed at designing a gene therapy for ND4; its coding sequence was associated with the cis-acting elements of the human COX10 mRNA to allow the efficient mitochondrial delivery of the protein. After ocular administration to adult rats of a recombinant adeno-associated viral vector containing the human ND4 gene, we demonstrated that: (i) the sustained expression of human ND4 did not lead to harmful effects, instead the human protein is efficiently imported inside the mitochondria and assembled in respiratory chain complex I; (ii) the presence of the human protein in the experimental model of Leber hereditary optic neuropathy significantly prevents retinal ganglion cell degeneration and preserves both complex I function in optic nerves and visual function. Hence, the use of optimized allotopic expression is relevant for treating mitochondrial disorders due to mutations in the organelle genome.
Collapse
|
43
|
Dunn DA, Pinkert CA. Allotopic expression of ATP6 in the mouse as a transgenic model of mitochondrial disease. Methods Mol Biol 2015; 1265:255-69. [PMID: 25634280 DOI: 10.1007/978-1-4939-2288-8_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Progress in animal modeling of polymorphisms and mutations in mitochondrial DNA (mtDNA) is not as developed as nuclear transgenesis due to a host of cellular and physiological distinctions. mtDNA mutation modeling is of critical importance as mutations in the mitochondrial genome give rise to a variety of pathological conditions and play a contributing role in many others. Nuclear localization and transcription of mtDNA genes followed by cytoplasmic translation and transport into mitochondria (allotopic expression, AE) provide an opportunity to create in vivo modeling of a targeted mutation in mitochondrial genes and has been suggested as a strategy for gene replacement therapy in patients harboring mitochondrial DNA mutations. Here, we use our AE approach to transgenic mouse modeling of the pathogenic human T8993G mutation in mtATP6 as a case study for designing AE animal models.
Collapse
Affiliation(s)
- David A Dunn
- Department of Biological Sciences, State University of New York, Oswego, NY, USA
| | | |
Collapse
|
44
|
Gene therapy for mitochondrial diseases: Leber Hereditary Optic Neuropathy as the first candidate for a clinical trial. C R Biol 2014; 337:193-206. [PMID: 24702846 DOI: 10.1016/j.crvi.2013.11.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 11/28/2013] [Indexed: 12/30/2022]
Abstract
Mitochondrial disorders cannot be ignored anymore in most medical disciplines; indeed their minimum estimated prevalence is superior to 1 in 5000 births. Despite the progress made in the last 25 years on the identification of gene mutations causing mitochondrial pathologies, only slow progress was made towards their effective treatments. Ocular involvement is a frequent feature in mitochondrial diseases and corresponds to severe and irreversible visual handicap due to retinal neuron loss and optic atrophy. Interestingly, three clinical trials for Leber Congenital Amaurosis due to RPE65 mutations are ongoing since 2007. Overall, the feasibility and safety of ocular Adeno-Associated Virus delivery in adult and younger patients and consistent visual function improvements have been demonstrated. The success of gene-replacement therapy for RPE65 opens the way for the development of similar approaches for a broad range of eye disorders, including those with mitochondrial etiology such as Leber Hereditary Optic Neuropathy (LHON).
Collapse
|
45
|
Sadun AA, La Morgia C, Carelli V. Leber’s hereditary optic neuropathy: new quinone therapies change the paradigm. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.12.27] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
46
|
Gueven N, Faldu D. Therapeutic strategies for Leber's hereditary optic neuropathy: A current update. Intractable Rare Dis Res 2013; 2:130-5. [PMID: 25343117 PMCID: PMC4204556 DOI: 10.5582/irdr.2013.v2.4.130] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 11/14/2013] [Accepted: 11/15/2013] [Indexed: 11/05/2022] Open
Abstract
Leber's hereditary optic neuropathy (LHON) is a rare mitochondrial retinopathy, caused by mutations in subunits of complex I of the respiratory chain, which leads to elevated levels of oxidative stress and an insufficient energy supply. This molecular pathology is thought to be responsible for the dysfunction and eventual apoptotic loss of retinal ganglion cells in the eye, which ultimately results in blindness. Many strategies, ranging from neuroprotectants, antioxidants, anti-apoptotic- and anti-inflammatory compounds have been tested with mixed results. Currently, the most promising compounds are short-chain quinones that have been shown to protect the vision of LHON patients during the early stages of the disease. This commentary gives a brief overview on the current status of tested therapeutics and also addresses future developments such as the use of gene therapy that hopefully will provide safe and efficient therapy options for all LHON patients.
Collapse
Affiliation(s)
- Nuri Gueven
- School of Pharmacy, University of Tasmania, Hobart, Australia
- Address correspondence to: Dr. Nuri Gueven, School of Pharmacy, University of Tasmania, Private Bag 26, Hobart, TAS 7001, Australia. E-mail:
| | - Dharmesh Faldu
- School of Pharmacy, University of Tasmania, Hobart, Australia
| |
Collapse
|
47
|
Maresca A, la Morgia C, Caporali L, Valentino ML, Carelli V. The optic nerve: a "mito-window" on mitochondrial neurodegeneration. Mol Cell Neurosci 2013; 55:62-76. [PMID: 22960139 PMCID: PMC3629569 DOI: 10.1016/j.mcn.2012.08.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 07/27/2012] [Accepted: 08/06/2012] [Indexed: 01/16/2023] Open
Abstract
Retinal ganglion cells (RGCs) project their long axons, composing the optic nerve, to the brain, transmitting the visual information gathered by the retina, ultimately leading to formed vision in the visual cortex. The RGC cellular system, representing the anterior part of the visual pathway, is vulnerable to mitochondrial dysfunction and optic atrophy is a very frequent feature of mitochondrial and neurodegenerative diseases. The start of the molecular era of mitochondrial medicine, the year 1988, was marked by the identification of a maternally inherited form of optic atrophy, Leber's hereditary optic neuropathy, as the first disease due to mitochondrial DNA point mutations. The field of mitochondrial medicine has expanded enormously over the last two decades and many neurodegenerative diseases are now known to have a primary mitochondrial etiology or mitochondrial dysfunction plays a relevant role in their pathogenic mechanism. Recent technical advancements in neuro-ophthalmology, such as optical coherence tomography, prompted a still ongoing systematic re-investigation of retinal and optic nerve involvement in neurodegenerative disorders. In addition to inherited optic neuropathies, such as Leber's hereditary optic neuropathy and dominant optic atrophy, and in addition to the syndromic mitochondrial encephalomyopathies or mitochondrial neurodegenerative disorders such as some spinocerebellar ataxias or familial spastic paraparesis and other disorders, we draw attention to the involvement of the optic nerve in classic age-related neurodegenerative disorders such as Parkinson and Alzheimer disease. We here provide an overview of optic nerve pathology in these different clinical settings, and we review the possible mechanisms involved in the pathogenesis of optic atrophy. This may be a model of general value for the field of neurodegeneration. This article is part of a Special Issue entitled 'Mitochondrial function and dysfunction in neurodegeneration'.
Collapse
Affiliation(s)
| | | | | | | | - Valerio Carelli
- Corresponding author at: IRCCS Institute of Neurological Sciences of Bologna, Department of Neurological Sciences, University of Bologna, Via Ugo Foscolo 7, 40123 Bologna, Italy. Fax: + 39 051 2092751.
| |
Collapse
|
48
|
Iyer S. Novel therapeutic approaches for Leber's hereditary optic neuropathy. DISCOVERY MEDICINE 2013; 15:141-149. [PMID: 23545042 PMCID: PMC5652312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Many human childhood mitochondrial disorders result from abnormal mitochondrial DNA (mtDNA) and altered bioenergetics. These abnormalities span most of the mtDNA, demonstrating that there are no "unique" positions on the mitochondrial genome that when deleted or mutated produce a disease phenotype. This diversity implies that the relationship between mitochondrial genotype and clinical phenotype is very complex. The origins of clinical phenotypes are thus unclear, fundamentally difficult-to-treat, and are usually clinically devastating. Current treatment is largely supportive and the disorders progress relentlessly causing significant morbidity and mortality. Vitamin supplements and pharmacological agents have been used in isolated cases and clinical trials, but the efficacy of these interventions is unclear. In spite of recent advances in the understanding of the pathogenesis of mitochondrial diseases, a cure remains elusive. An optimal cure would be gene therapy, which involves introducing the missing gene(s) into the mitochondria to complement the defect. Our recent research results indicate the feasibility of an innovative protein-transduction ("protofection") technology, consisting of a recombinant mitochondrial transcription factor A (TFAM) that avidly binds mtDNA and permits efficient targeting into mitochondria in situ and in vivo. Thus, the development of gene therapy for treating mitochondrial disease offers promise, because it may circumvent the clinical abnormalities and the current inability to treat individual disorders in affected individuals. This review aims to focus on current treatment options and future therapeutics in mitochondrial disease treatment with a special emphasis on Leber's hereditary optic neuropathy.
Collapse
Affiliation(s)
- Shilpa Iyer
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia 23284, USA.
| |
Collapse
|
49
|
Gueven N, Faldu D. Idebenone treatment in Leber's hereditary optic neuropathy: rationale and efficacy. Expert Opin Orphan Drugs 2013. [DOI: 10.1517/21678707.2013.772894] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
50
|
|