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Bacman SR, Barrera-Paez JD, Pinto M, Van Booven D, Stewart JB, Griswold AJ, Moraes CT. mitoTALEN reduces the mutant mtDNA load in neurons. Mol Ther Nucleic Acids 2024; 35:102132. [PMID: 38404505 PMCID: PMC10883830 DOI: 10.1016/j.omtn.2024.102132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 01/29/2024] [Indexed: 02/27/2024]
Abstract
Mutations within mtDNA frequently give rise to severe encephalopathies. Given that a majority of these mtDNA defects exist in a heteroplasmic state, we harnessed the precision of mitochondrial-targeted TALEN (mitoTALEN) to selectively eliminate mutant mtDNA within the CNS of a murine model harboring a heteroplasmic mutation in the mitochondrial tRNA alanine gene (m.5024C>T). This targeted approach was accomplished by the use of AAV-PHP.eB and a neuron-specific synapsin promoter for effective neuronal delivery and expression of mitoTALEN. We found that most CNS regions were effectively transduced and showed a significant reduction in mutant mtDNA. This reduction was accompanied by an increase in mitochondrial tRNA alanine levels, which are drastically reduced by the m.5024C>T mutation. These results showed that mitochondrial-targeted gene editing can be effective in reducing CNS-mutant mtDNA in vivo, paving the way for clinical trials in patients with mitochondrial encephalopathies.
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Affiliation(s)
- Sandra R. Bacman
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jose Domingo Barrera-Paez
- Graduate Program in Human Genetics and Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Milena Pinto
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Derek Van Booven
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - James B. Stewart
- Biosciences Institute, Faculty of Medical Sciences, Wellcome Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne, UK
| | - Anthony J. Griswold
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Carlos T. Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL, USA
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2
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Shoop WK, Lape J, Trum M, Powell A, Sevigny E, Mischler A, Bacman SR, Fontanesi F, Smith J, Jantz D, Gorsuch CL, Moraes CT. Efficient elimination of MELAS-associated m.3243G mutant mitochondrial DNA by an engineered mitoARCUS nuclease. Nat Metab 2023; 5:2169-2183. [PMID: 38036771 PMCID: PMC10730414 DOI: 10.1038/s42255-023-00932-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 10/16/2023] [Indexed: 12/02/2023]
Abstract
Nuclease-mediated editing of heteroplasmic mitochondrial DNA (mtDNA) seeks to preferentially cleave and eliminate mutant mtDNA, leaving wild-type genomes to repopulate the cell and shift mtDNA heteroplasmy. Various technologies are available, but many suffer from limitations based on size and/or specificity. The use of ARCUS nucleases, derived from naturally occurring I-CreI, avoids these pitfalls due to their small size, single-component protein structure and high specificity resulting from a robust protein-engineering process. Here we describe the development of a mitochondrial-targeted ARCUS (mitoARCUS) nuclease designed to target one of the most common pathogenic mtDNA mutations, m.3243A>G. mitoARCUS robustly eliminated mutant mtDNA without cutting wild-type mtDNA, allowing for shifts in heteroplasmy and concomitant improvements in mitochondrial protein steady-state levels and respiration. In vivo efficacy was demonstrated using a m.3243A>G xenograft mouse model with mitoARCUS delivered systemically by adeno-associated virus. Together, these data support the development of mitoARCUS as an in vivo gene-editing therapeutic for m.3243A>G-associated diseases.
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Affiliation(s)
- Wendy K Shoop
- Precision BioSciences, Durham, NC, USA
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, USA
| | | | | | | | | | | | - Sandra R Bacman
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Flavia Fontanesi
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, USA
| | | | | | | | - Carlos T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA.
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3
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Abstract
The study of the mitochondrial DNA (mtDNA) has been hampered by the lack of methods to genetically manipulate the mitochondrial genome in living animal cells. This limitation has been partially alleviated by the ability to transfer mitochondria (and their mtDNAs) from one cell into another, as long as they are from the same species. This is done by isolating mtDNA-containing cytoplasts and fusing these to cells lacking mtDNA. This transmitochondrial cytoplasmic hybrid (cybrid) technology has helped the field understand the mechanism of several pathogenic mutations. In this chapter, we describe procedures to obtain transmitochondrial cybrids.
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Affiliation(s)
- Sandra R Bacman
- Department of Neurology, University of Miami School of Medicine, Miami, FL, United States
| | - Nadee Nissanka
- Department of Neurology, University of Miami School of Medicine, Miami, FL, United States
| | - Carlos T Moraes
- Department of Neurology, University of Miami School of Medicine, Miami, FL, United States.
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Zekonyte U, Bacman SR, Moraes CT. DNA-editing enzymes as potential treatments for heteroplasmic mtDNA diseases. J Intern Med 2020; 287:685-697. [PMID: 32176378 PMCID: PMC7260085 DOI: 10.1111/joim.13055] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 12/04/2019] [Accepted: 12/11/2019] [Indexed: 12/13/2022]
Abstract
Mutations in the mitochondrial genome are the cause of many debilitating neuromuscular disorders. Currently, there is no cure or treatment for these diseases, and symptom management is the only relief doctors can provide. Although supplements and vitamins are commonly used in treatment, they provide little benefit to the patient and are only palliative. This is why gene therapy is a promising research topic to potentially treat and, in theory, even cure diseases caused by mutations in the mitochondrial DNA (mtDNA). Mammalian cells contain approximately a thousand copies of mtDNA, which can lead to a phenomenon called heteroplasmy, where both wild-type and mutant mtDNA molecules co-exist within the cell. Disease only manifests once the per cent of mutant mtDNA reaches a high threshold (usually >80%), which causes mitochondrial dysfunction and reduced ATP production. This is a useful feature to take advantage of for gene therapy applications, as not every mutant copy of mtDNA needs to be eliminated, but only enough to shift the heteroplasmic ratio below the disease threshold. Several DNA-editing enzymes have been used to shift heteroplasmy in cell culture and mice. This review provides an overview of these enzymes and discusses roadblocks of applying these to gene therapy in humans.
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Affiliation(s)
- U Zekonyte
- From the, Graduate Program in Human Genetics and Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - S R Bacman
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - C T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
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Pereira CV, Peralta S, Arguello T, Bacman SR, Diaz F, Moraes CT. Myopathy reversion in mice after restauration of mitochondrial complex I. EMBO Mol Med 2020; 12:e10674. [PMID: 31916679 PMCID: PMC7005622 DOI: 10.15252/emmm.201910674] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 12/04/2019] [Accepted: 12/06/2019] [Indexed: 01/03/2023] Open
Abstract
Myopathies are common manifestations of mitochondrial diseases. To investigate whether gene replacement can be used as an effective strategy to treat or cure mitochondrial myopathies, we have generated a complex I conditional knockout mouse model lacking NDUFS3 subunit in skeletal muscle. NDUFS3 protein levels were undetectable in muscle of 15‐day‐old smKO mice, and myopathy symptoms could be detected by 2 months of age, worsening over time. rAAV9‐Ndufs3 delivered systemically into 15‐ to 18‐day‐old mice effectively restored NDUFS3 levels in skeletal muscle, precluding the development of the myopathy. To test the ability of rAAV9‐mediated gene replacement to revert muscle function after disease onset, we also treated post‐symptomatic, 2‐month‐old mice. The injected mice showed a remarkable improvement of the mitochondrial myopathy and biochemical parameters, which remained for the duration of the study. Our results showed that muscle pathology could be reversed after restoring complex I, which was absent for more than 2 months. These findings have far‐reaching implications for the ability of muscle to tolerate a mitochondrial defect and for the treatment of mitochondrial myopathies.
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Affiliation(s)
- Claudia V Pereira
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Susana Peralta
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Tania Arguello
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Sandra R Bacman
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Francisca Diaz
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Carlos T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA.,Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL, USA
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Pereira CV, Bacman SR, Arguello T, Zekonyte U, Williams SL, Edgell DR, Moraes CT. mitoTev-TALE: a monomeric DNA editing enzyme to reduce mutant mitochondrial DNA levels. EMBO Mol Med 2019; 10:emmm.201708084. [PMID: 30012581 PMCID: PMC6127889 DOI: 10.15252/emmm.201708084] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Pathogenic mitochondrial DNA (mtDNA) mutations often co‐exist with wild‐type molecules (mtDNA heteroplasmy). Phenotypes manifest when the percentage of mutant mtDNA is high (70–90%). Previously, our laboratory showed that mitochondria‐targeted transcription activator‐like effector nucleases (mitoTALENs) can eliminate mutant mtDNA from heteroplasmic cells. However, mitoTALENs are dimeric and relatively large, making it difficult to package their coding genes into viral vectors, limiting their clinical application. The smaller monomeric GIY‐YIG homing nuclease from T4 phage (I‐TevI) provides a potential alternative. We tested whether molecular hybrids (mitoTev‐TALEs) could specifically bind and cleave mtDNA of patient‐derived cybrids harboring different levels of the m.8344A>G mtDNA point mutation, associated with myoclonic epilepsy with ragged‐red fibers (MERRF). We tested two mitoTev‐TALE designs, one of which robustly shifted the mtDNA ratio toward the wild type. When this mitoTev‐TALE was tested in a clone with high levels of the MERRF mutation (91% mutant), the shift in heteroplasmy resulted in an improvement of oxidative phosphorylation function. mitoTev‐TALE provides an effective architecture for mtDNA editing that could facilitate therapeutic delivery of mtDNA editing enzymes to affected tissues.
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Affiliation(s)
- Claudia V Pereira
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Sandra R Bacman
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Tania Arguello
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Ugne Zekonyte
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Sion L Williams
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - David R Edgell
- Department of Biochemistry, Schulich School of Medicine and Dentistry University of Western Ontario, London, ON, Canada
| | - Carlos T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
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9
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Nissanka N, Bacman SR, Plastini MJ, Moraes CT. The mitochondrial DNA polymerase gamma degrades linear DNA fragments precluding the formation of deletions. Nat Commun 2018; 9:2491. [PMID: 29950568 PMCID: PMC6021392 DOI: 10.1038/s41467-018-04895-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 05/25/2018] [Indexed: 02/03/2023] Open
Abstract
Double-strand breaks in the mitochondrial DNA (mtDNA) result in the formation of linear fragments that are rapidly degraded. However, the identity of the nuclease(s) performing this function is not known. We found that the exonuclease function of the mtDNA polymerase gamma (POLG) is required for this rapid degradation of mtDNA fragments. POLG is recruited to linearized DNA fragments in an origin of replication-independent manner. Moreover, in the absence of POLG exonuclease activity, the prolonged existence of mtDNA linear fragments leads to increased levels of mtDNA deletions, which have been previously identified in the mutator mouse, patients with POLG mutations and normal aging. Mitochondrial DNA fragments are rapidly degraded when double strand breaks occur. Here the authors reveal that the exonuclease activity of polymerase gamma is important for efficient degradation of these fragments and to avoid formation of large deletions.
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Affiliation(s)
- Nadee Nissanka
- Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Sandra R Bacman
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Melanie J Plastini
- Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Carlos T Moraes
- Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL, 33136, USA. .,Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
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10
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Pinto M, Pickrell AM, Wang X, Bacman SR, Yu A, Hida A, Dillon LM, Morton PD, Malek TR, Williams SL, Moraes CT. Transient mitochondrial DNA double strand breaks in mice cause accelerated aging phenotypes in a ROS-dependent but p53/p21-independent manner. Cell Death Differ 2016; 24:288-299. [PMID: 27911443 DOI: 10.1038/cdd.2016.123] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/16/2016] [Accepted: 09/26/2016] [Indexed: 12/20/2022] Open
Abstract
We observed that the transient induction of mtDNA double strand breaks (DSBs) in cultured cells led to activation of cell cycle arrest proteins (p21/p53 pathway) and decreased cell growth, mediated through reactive oxygen species (ROS). To investigate this process in vivo we developed a mouse model where we could transiently induce mtDNA DSBs ubiquitously. This transient mtDNA damage in mice caused an accelerated aging phenotype, preferentially affecting proliferating tissues. One of the earliest phenotypes was accelerated thymus shrinkage by apoptosis and differentiation into adipose tissue, mimicking age-related thymic involution. This phenotype was accompanied by increased ROS and activation of cell cycle arrest proteins. Treatment with antioxidants improved the phenotype but the knocking out of p21 or p53 did not. Our results demonstrate that transient mtDNA DSBs can accelerate aging of certain tissues by increasing ROS. Surprisingly, this mtDNA DSB-associated senescence phenotype does not require p21/p53, even if this pathway is activated in the process.
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Affiliation(s)
- Milena Pinto
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Alicia M Pickrell
- Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Xiao Wang
- Graduate Program in Cancer Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Sandra R Bacman
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Aixin Yu
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Aline Hida
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Lloye M Dillon
- Department of Cell Biology and Anatomy, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Paul D Morton
- Department of Neurosurgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA.,Center for Neuroscience Research, Children's National Medical Center, Washington, DC 20010, USA
| | - Thomas R Malek
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Siôn L Williams
- 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.,Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA.,Graduate Program in Cancer Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.,Department of Cell Biology and Anatomy, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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11
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Bacman SR, Hashimoto M, Peralta S, Falk MJ, Chomyn A, Chan DC, Williams SL, Moraes CT. mitoTALENs as DNA editing tools for mitochondrial diseases. Mitochondrion 2015. [DOI: 10.1016/j.mito.2015.07.065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Reddy P, Ocampo A, Suzuki K, Luo J, Bacman SR, Williams SL, Sugawara A, Okamura D, Tsunekawa Y, Wu J, Lam D, Xiong X, Montserrat N, Esteban CR, Liu GH, Sancho-Martinez I, Manau D, Civico S, Cardellach F, Del Mar O'Callaghan M, Campistol J, Zhao H, Campistol JM, Moraes CT, Izpisua Belmonte JC. Selective elimination of mitochondrial mutations in the germline by genome editing. Cell 2015; 161:459-469. [PMID: 25910206 DOI: 10.1016/j.cell.2015.03.051] [Citation(s) in RCA: 200] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/05/2015] [Accepted: 03/25/2015] [Indexed: 01/15/2023]
Abstract
Mitochondrial diseases include a group of maternally inherited genetic disorders caused by mutations in mtDNA. In most of these patients, mutated mtDNA coexists with wild-type mtDNA, a situation known as mtDNA heteroplasmy. Here, we report on a strategy toward preventing germline transmission of mitochondrial diseases by inducing mtDNA heteroplasmy shift through the selective elimination of mutated mtDNA. As a proof of concept, we took advantage of NZB/BALB heteroplasmic mice, which contain two mtDNA haplotypes, BALB and NZB, and selectively prevented their germline transmission using either mitochondria-targeted restriction endonucleases or TALENs. In addition, we successfully reduced human mutated mtDNA levels responsible for Leber's hereditary optic neuropathy (LHOND), and neurogenic muscle weakness, ataxia, and retinitis pigmentosa (NARP), in mammalian oocytes using mitochondria-targeted TALEN (mito-TALENs). Our approaches represent a potential therapeutic avenue for preventing the transgenerational transmission of human mitochondrial diseases caused by mutations in mtDNA. PAPERCLIP.
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Affiliation(s)
- Pradeep Reddy
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Alejandro Ocampo
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Keiichiro Suzuki
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Jinping Luo
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Sandra R Bacman
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Sion L Williams
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Atsushi Sugawara
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Daiji Okamura
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Yuji Tsunekawa
- Laboratory for Cell Asymmetry, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan
| | - Jun Wu
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - David Lam
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Xiong Xiong
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Nuria Montserrat
- Pluripotent Stem Cells and Organ Regeneration, Institute for Bioengineering of Catalonia (IBEC), Barcelona 08028, Spain
| | | | - Guang-Hui Liu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; Center for Molecular and Translational Medicine (CMTM), Beijing 100101, China; Beijing Institute for Brain Disorders, Beijing100069, China
| | | | - Dolors Manau
- Institut Clínic of Gynecology, Obstetrics and Neonatology (ICGON), Hospital Clinic, University of Barcelona, Barcelona 08036, Spain
| | - Salva Civico
- Institut Clínic of Gynecology, Obstetrics and Neonatology (ICGON), Hospital Clinic, University of Barcelona, Barcelona 08036, Spain
| | - Francesc Cardellach
- Mitochondrial Research Laboratory, IDIBAPS/CIBER on Rare Diseases, University of Barcelona and Internal Medicine Department, Hospital Clínic, University of Barcelona, Barcelona 08036, Spain
| | - Maria Del Mar O'Callaghan
- Neuropediatric Department/CIBERER, Hospital Universitari Sant Joan de Déu, Esplugues de Llobregat 08950, Spain
| | - Jaime Campistol
- Neuropediatric Department/CIBERER, Hospital Universitari Sant Joan de Déu, Esplugues de Llobregat 08950, Spain
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Josep M Campistol
- Renal Division, Hospital Clinic, University of Barcelona, IDIBAPS, Barcelona 08036, Spain
| | - Carlos T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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13
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Moraes CT, Bacman SR, Williams SL. Manipulating mitochondrial genomes in the clinic: playing by different rules. Trends Cell Biol 2014; 24:209-11. [PMID: 24679453 DOI: 10.1016/j.tcb.2014.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 02/10/2014] [Accepted: 02/11/2014] [Indexed: 11/19/2022]
Abstract
Recently, several publications have surfaced describing methods to manipulate mitochondrial genomes in tissues and embryos. With them, a somewhat sensationalistic uproar about the generation of children with 'three parents' has dominated the discussion in the lay media. It is important that society understands the singularities of mitochondrial genetics to judge these procedures in a rational light, so that this ongoing discussion does not preclude the helping of patients and families harboring mutated mitochondrial genomes.
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Affiliation(s)
- Carlos T Moraes
- University of Miami Miller School of Medicine, Department of Neurology and Cell Biology, 1420 NW 9th Avenue, Rm 229, Miami, FL 33136, USA.
| | - Sandra R Bacman
- University of Miami Miller School of Medicine, Department of Neurology and Cell Biology, 1420 NW 9th Avenue, Rm 229, Miami, FL 33136, USA
| | - Sion L Williams
- University of Miami Miller School of Medicine, Department of Neurology and Cell Biology, 1420 NW 9th Avenue, Rm 229, Miami, FL 33136, USA
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14
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Abstract
For more than a decade, mitochondria-targeted nucleases have been used to promote double-strand breaks in the mitochondrial genome. This was done in mitochondrial DNA (mtDNA) homoplasmic systems, where all mtDNA molecules can be affected, to create models of mitochondrial deficiencies. Alternatively, they were also used in a heteroplasmic model, where only a subset of the mtDNA molecules were substrates for cleavage. The latter approach showed that mitochondrial-targeted nucleases can reduce mtDNA haplotype loads in affected tissues, with clear implications for the treatment of patients with mitochondrial diseases. In the last few years, designer nucleases, such as ZFN and TALEN, have been adapted to cleave mtDNA, greatly expanding the potential therapeutic use. This chapter describes the techniques and approaches used to test these designer enzymes.
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Affiliation(s)
- Sandra R Bacman
- Department of Neurology, University of Miami School of Medicine, Miami, Florida, USA
| | - Sion L Williams
- Department of Neurology, University of Miami School of Medicine, Miami, Florida, USA
| | - Milena Pinto
- Department of Neurology, University of Miami School of Medicine, Miami, Florida, USA
| | - Carlos T Moraes
- Department of Neurology, University of Miami School of Medicine, Miami, Florida, USA.
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15
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Pickrell AM, Wang X, Pinto M, Bacman SR, Yu A, Hida A, Dillon LM, Morton PD, Malek TR, Williams SL, Moraes CT. Mitochondrial DNA damage contributes to premature aging through p53-dependent response mechanisms. Mitochondrion 2012. [DOI: 10.1016/j.mito.2012.07.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
Mitochondrial diseases are very heterogeneous and can affect different tissues and organs. Moreover, they can be caused by genetic defects in either nuclear or mitochondrial DNA as well as by environmental factors. All of these factors have made the development of therapies difficult. In this review article, we will discuss emerging approaches to the therapy of mitochondrial disorders, some of which are targeted to specific conditions whereas others may be applicable to a more diverse group of patients.
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Affiliation(s)
- Tina Wenz
- Department of Neurology, University of Miami School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, USA
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17
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Bacman SR, Williams SL, Garcia S, Moraes CT. Organ-specific shifts in mtDNA heteroplasmy following systemic delivery of a mitochondria-targeted restriction endonuclease. Gene Ther 2010; 17:713-20. [PMID: 20220783 PMCID: PMC3175591 DOI: 10.1038/gt.2010.25] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Most pathogenic mtDNA mutations are heteroplasmic and there is a clear correlation between high levels of mutated mtDNA in a tissue and pathology. We have found that in vivo double strand breaks (DSB) in mtDNA lead to digestion of cleaved mtDNA and replication of residual mtDNA. Therefore, if DSB could be targeted to mutations in mtDNA, mutant genomes could be eliminated and the wild-type mtDNA would repopulate the cells. This can be achieved by using mitochondria-targeted restriction endonucleases as a means to degrade specific mtDNA haplotypes in heteroplasmic cells or tissues. In the present work we investigated the potential of systemic delivery of mitochondria-targeted restriction endonucleases to reduce the proportion of mutant mtDNA in specific tissues. Using the asymptomatic NZB/BALB mtDNA heteroplasmic mouse as a model, we found that a mitochondria-targeted ApaLI (that cleaves BALB mtDNA at a single site and does not cleave NZB mtDNA) increased the proportion of NZB mtDNA in target tissues. This was observed in heart, using a cardiotropic adeno-associated virus type-6 (AAV6) and in liver, using the hepatotropic adenovirus type-5 (Ad5). No mtDNA depletion or loss of cytochrome c oxidase activity was observed in any of these tissues. These results demonstrate the potential of systemic delivery of viral vectors to specific organs for the therapeutic application of mitochondria-targeted restriction enzymes in mtDNA disorders.
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Affiliation(s)
- S R Bacman
- Department of Neurology, University of Miami School of Medicine, Miami, FL 33136, USA
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Bacman SR, Williams SL, Moraes CT. Intra- and inter-molecular recombination of mitochondrial DNA after in vivo induction of multiple double-strand breaks. Nucleic Acids Res 2009; 37:4218-26. [PMID: 19435881 PMCID: PMC2715231 DOI: 10.1093/nar/gkp348] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
To investigate mtDNA recombination induced by multiple double strand breaks (DSBs) we used a mitochondria-targeted form of the ScaI restriction endonuclease to introduce DSBs in heteroplasmic mice and cells in which we were able to utilize haplotype differences to trace the origin of recombined molecules. ScaI cleaves multiple sites in each haplotype of the heteroplasmic mice (five in NZB and three in BALB mtDNA) and prolonged expression causes severe mtDNA depletion. After a short pulse of restriction enzyme expression followed by a long period of recovery, mitochondrial genomes with large deletions were detected by PCR. Curiously, we found that some ScaI sites were more commonly involved in recombined molecules than others. In intra-molecular recombination events, deletion breakpoints were close to or upstream of ScaI cleavage sites, confirming the recombinogenic character of DSBs in mtDNA. A region adjacent to the D-loop was preferentially involved in recombination of all molecules. Sequencing through NZB and BALB haplotype markers in recombined molecules enabled us to show that in addition to intra-molecular mtDNA recombination, rare inter-molecular mtDNA recombination events can also occur. This study underscores the role of DSBs in the generation of mtDNA rearrangements and supports the existence of recombination hotspots.
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Affiliation(s)
- Sandra R Bacman
- Department of Neurology, University of Miami School of Medicine, Miami, FL 33136, USA
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Bacman SR, Williams SL, Hernandez D, Moraes CT. Modulating mtDNA heteroplasmy by mitochondria-targeted restriction endonucleases in a 'differential multiple cleavage-site' model. Gene Ther 2007; 14:1309-18. [PMID: 17597792 PMCID: PMC2771437 DOI: 10.1038/sj.gt.3302981] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The ability to manipulate mitochondrial DNA (mtDNA) heteroplasmy would provide a powerful tool to treat mitochondrial diseases. Recent studies showed that mitochondria-targeted restriction endonucleases can modify mtDNA heteroplasmy in a predictable and efficient manner if it recognizes a single site in the mutant mtDNA. However, the applicability of such model is limited to mutations that create a novel cleavage site, not present in the wild-type mtDNA. We attempted to extend this approach to a 'differential multiple cleavage site' model, where an mtDNA mutation creates an extra restriction site to the ones normally present in the wild-type mtDNA. Taking advantage of a heteroplasmic mouse model harboring two haplotypes of mtDNA (NZB/BALB) and using adenovirus as a gene vector, we delivered a mitochondria-targeted Scal restriction endonuclease to different mouse tissues. Scal recognizes five sites in the NZB mtDNA but only three in BALB mtDNA. Our results showed that changes in mtDNA heteroplasmy were obtained by the expression of mitochondria-targeted ScaI in both liver, after intravenous injection, and in skeletal muscle, after intramuscular injection. Although mtDNA depletion was an undesirable side effect, our data suggest that under a regulated expression system, mtDNA depletion could be minimized and restriction endonucleases recognizing multiple sites could have a potential for therapeutic use.
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Affiliation(s)
- SR Bacman
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - SL Williams
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - D Hernandez
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - CT Moraes
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL, USA
- Department of Cell Biology and Anatomy, Miller School of Medicine, University of Miami, Miami, FL, USA
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Affiliation(s)
- Sandra R Bacman
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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Bacman SR, Williams SL, Hernandez D, Battersby BJ, Shoubridge EA, Moraes CT. Manipulating heteroplasmy by delivering restriction endonuclease to mitochondria in a “differential multiple cleavage-site” model. Mitochondrion 2006. [DOI: 10.1016/j.mito.2006.08.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Bacman SR, Bradley WG, Moraes CT. Mitochondrial involvement in amyotrophic lateral sclerosis: trigger or target? Mol Neurobiol 2006; 33:113-31. [PMID: 16603792 DOI: 10.1385/mn:33:2:113] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Revised: 11/30/1999] [Accepted: 07/19/2005] [Indexed: 12/11/2022]
Abstract
Despite numerous reports demonstrating mitochondrial abnormalities associated with amyotrophic lateral sclerosis (ALS), the role of mitochondrial dysfunction in the disease onset and progression remains unknown. The intrinsic mitochondrial apoptotic program is activated in the central nervous system of mouse models of ALS harboring mutant superoxide dismutase 1 protein. This is associated with the release of cytochrome-c from the mitochondrial intermembrane space and mitochondrial swelling. However, it is unclear if the observed mitochondrial changes are caused by the decreasing cellular viability or if these changes precede and actually trigger apoptosis. This article discusses the current evidence for mitochondrial involvement in familial and sporadic ALS and concludes that mitochondria is likely to be both a trigger and a target in ALS and that their demise is a critical step in the motor neuron death.
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Affiliation(s)
- Sandra R Bacman
- Department of Neurology, University of Miami, Miller School of Medicine, FL, USA
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Kirkinezos IG, Bacman SR, Hernandez D, Oca-Cossio J, Arias LJ, Perez-Pinzon MA, Bradley WG, Moraes CT. Cytochrome c association with the inner mitochondrial membrane is impaired in the CNS of G93A-SOD1 mice. J Neurosci 2005; 25:164-72. [PMID: 15634778 PMCID: PMC6725219 DOI: 10.1523/jneurosci.3829-04.2005] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A "gain-of-function" toxic property of mutant Cu-Zn superoxide dismutase 1 (SOD1) is involved in the pathogenesis of some familial cases of amyotrophic lateral sclerosis (ALS). Expression of a mutant form of the human SOD1 gene in mice causes a degeneration of motor neurons, leading to progressive muscle weakness and hindlimb paralysis. Transgenic mice overexpressing a mutant human SOD1 gene (G93A-SOD1) were used to examine the mitochondrial involvement in familial ALS. We observed a decrease in mitochondrial respiration in brain and spinal cord of the G93A-SOD1 mice. This decrease was significant only at the last step of the respiratory chain (complex IV), and it was not observed in transgenic wild-type SOD1 and nontransgenic mice. Interestingly, this decrease was evident even at a very early age in mice, long before any clinical symptoms arose. The effect seemed to be CNS specific, because no decrease was observed in liver mitochondria. Differences in complex IV respiration between brain mitochondria of G93A-SOD1 and control mice were abolished when reduced cytochrome c was used as an electron donor, pinpointing the defect to cytochrome c. Submitochondrial studies showed that cytochrome c in the brain of G93A-SOD1 mice had a reduced association with the inner mitochondrial membrane (IMM). Brain mitochondrial lipids, including cardiolipin, had increased peroxidation in G93A-SOD1 mice. These results suggest a mechanism by which mutant SOD1 can disrupt the association of cytochrome c with the IMM, thereby priming an apoptotic program.
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Affiliation(s)
- Ilias G Kirkinezos
- Department of Cell Biology and Anatomy, University of Miami School of Medicine, Miami, Florida 33136, USA
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Bacman SR, Atencio DP, Moraes CT. Decreased mitochondrial tRNALys steady-state levels and aminoacylation are associated with the pathogenic G8313A mitochondrial DNA mutation. Biochem J 2003; 374:131-6. [PMID: 12737626 PMCID: PMC1223569 DOI: 10.1042/bj20030222] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2003] [Revised: 04/10/2003] [Accepted: 05/09/2003] [Indexed: 11/17/2022]
Abstract
Mutations in human mitochondrial tRNA genes cause a number of multisystemic disorders. A G-to-A transition at position 8313 (G8313A) transition in the mitochondrial tRNALys gene has been associated with a childhood syndrome characterized by gastrointestinal-system involvement and encephaloneuropathy. We have used transmitochondrial cybrid clones harbouring patient-derived mitochondrial DNA with the G8313A mutation for the study of the molecular pathogenesis. Our results showed that mutant mitochondrial cybrids respired poorly, and had severely defective mitochondrial protein synthesis and respiratory-chain-enzyme activity. Mutant cybrids also showed a marked decrease in tRNALys steady-state levels and aminoacylation, suggesting that these molecular abnormalities may underlie the pathogenesis of the mitochondrial G8313A mutation.
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Affiliation(s)
- Sandra R Bacman
- Department of Neurology, University of Miami School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, USA
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Noher de Halac I, Bacman SR, de Kremer RD. Histoenzymology of oxidases and dehydrogenases in peripheral blood lymphocytes and monocytes for the study of mitochondrial oxidative phosphorylation. Histochem J 2000; 32:133-7. [PMID: 10841308 DOI: 10.1023/a:1004078705513] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Histoenzymological methods usually performed on muscle fibres have been adapted to assess the functioning of oxidative phosphorylation in human circulating blood lymphocytes and monocytes. Oxidases and dehydrogenases were analysed in lymphocyte/monocyte smears. The specificity of each histoenzymological reaction was tested using a specific respiratory chain inhibitor: rotenone for NADH diaphorase, thenoyltrifluoroacetone for succinate dehydrogenase, potassium cyanide for cytochrome c oxidase and oligomycin for ATPase. Complex I activity was detected, but inhibition with rotenone was incomplete. Complexes II, IV and V were almost completely inhibited. These observations indicate that histoenzymology is a valuable method for detecting the activity of these oxidative phosphorylation enzymes in lymphocytes and monocytes. The histoenzymology tests performed on fresh peripheral blood cells resembled those used for muscle biopsies. They could be useful for the diagnosis of respiratory chain disorders in patients.
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Affiliation(s)
- I Noher de Halac
- Centro de Estudios de la Metabolopatías Congénitas, Hospital de Niños, Cátedra de Clínica Pediátrica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
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Bacman SR, Berra A, Sterin-Borda L, Borda ES. Human primary Sjögren's syndrome autoantibodies as mediators of nitric oxide release coupled to lacrimal gland muscarinic acetylcholine receptors. Curr Eye Res 1998; 17:1135-42. [PMID: 9872535 DOI: 10.1076/ceyr.17.12.1135.5124] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
IgG obtained from sera of primary Sjögren's syndrome (pSS-IgG) patients and its interaction with M3 muscarinic cholinoceptors of rat exorbital lacrimal glands were studied by indirect immunofluorescence (IFI) and binding assay. Primary Sjögren's syndrome IgG stained epithelial cells with a continuous fluorescence pattern. The IFI imagen was attenuated by incubating the pSS-IgG with a synthetic peptide corresponding to the second extracellular loop of M3 muscarinic cholinoceptor. Primary SS-IgG was also able to bound irreversibly to muscarinic acetylcholine receptors (mAChRs) displacing the specific cholinergic antagonist QNB. Moreover, these antibodies triggered intracellular signals coupled to M3 muscaric cholinoceptors such as nitric oxide synthase (NOS) activation and cGMP production. Both primary Sjögren's syndrome IgG effects mimicked carbachol action and were abrogated by specific muscarinic antagonist 4-DAMP. The nitric oxide pathway through muscarinic cholinoceptors activation by pSS-IgG on rat exorbital lacrimal gland is also described. We proposed that chronic interaction of these autoantibodies on lacrimal gland muscarinic acetylcholine receptors could lead to tissue damage through nitric oxide release after immunological stimulation.
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Affiliation(s)
- S R Bacman
- CEFYBO (CONICET), Pharmacology Department, School of Dentistry, Buenos Aires University, Argentina
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