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Belbellaa B, Reutenauer L, Messaddeq N, Monassier L, Puccio H. High Levels of Frataxin Overexpression Lead to Mitochondrial and Cardiac Toxicity in Mouse Models. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2020; 19:120-138. [PMID: 33209958 PMCID: PMC7648087 DOI: 10.1016/j.omtm.2020.08.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 08/27/2020] [Indexed: 12/18/2022]
Abstract
Friedreich ataxia (FA) is currently an incurable inherited mitochondrial disease caused by reduced levels of frataxin (FXN). Cardiac dysfunction is the main cause of premature death in FA. Adeno-associated virus (AAV)-mediated gene therapy constitutes a promising approach for FA, as demonstrated in cardiac and neurological mouse models. While the minimal therapeutic level of FXN protein to be restored and biodistribution have recently been defined for the heart, it is unclear if FXN overexpression could be harmful. Indeed, depending on the vector delivery route and dose administered, the resulting FXN protein level could reach very high levels in the heart, cerebellum, or off-target organs such as the liver. The present study demonstrates safety of FXN cardiac overexpression up to 9-fold the normal endogenous level but significant toxicity to the mitochondria and heart above 20-fold. We show gradual severity with increasing FXN overexpression, ranging from subclinical cardiotoxicity to left ventricle dysfunction. This appears to be driven by impairment of the mitochondria respiratory chain and ultrastructure, which leads to cardiomyocyte subcellular disorganization, cell death, and fibrosis. Overall, this study underlines the need, during the development of gene therapy approaches, to consider appropriate vector expression level, long-term safety, and biomarkers to monitor such events.
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Affiliation(s)
- Brahim Belbellaa
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch 67404, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch 67404, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch 67404, France.,Université de Strasbourg, Illkirch 67404, France
| | - Laurence Reutenauer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch 67404, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch 67404, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch 67404, France.,Université de Strasbourg, Illkirch 67404, France
| | - Nadia Messaddeq
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch 67404, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch 67404, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch 67404, France.,Université de Strasbourg, Illkirch 67404, France
| | - Laurent Monassier
- Laboratoire de Pharmacologie et Toxicologie NeuroCardiovasculaire EA7296, Faculté de Médecine, Strasbourg 67085, France
| | - Hélène Puccio
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch 67404, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch 67404, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch 67404, France.,Université de Strasbourg, Illkirch 67404, France
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Nani JP, Peñagaricano F. Whole-genome homozygosity mapping reveals candidate regions affecting bull fertility in US Holstein cattle. BMC Genomics 2020; 21:338. [PMID: 32366228 PMCID: PMC7199307 DOI: 10.1186/s12864-020-6758-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 04/27/2020] [Indexed: 01/10/2023] Open
Abstract
Background Achieving rapid genetic progress while maintaining adequate genetic diversity is one of the main challenges facing the dairy industry. The increase in inbreeding can be used to monitor the loss of genetic diversity. Inbreeding tends to increase the proportion of homozygous loci, some of which cause homozygosity of recessive alleles that results in reduced performance. This phenomenon is known as inbreeding depression and tends to be most prominent on fitness-related traits, such as male fertility. Traditionally, inbreeding has been monitored using pedigree information, or more recently, genomic data. Alternatively, it can be quantified using runs of homozygosity (ROH), i.e., contiguous lengths of homozygous genotypes observed in an individual’s chromosome. Results The objective of this study was to evaluate the association between ROH and sire conception rate. ROH were evaluated using 268 k genetic markers in 11,790 US Holstein bulls. Interestingly, either the sum, mean, or maximum length of ROH were negatively associated with bull fertility. The association analysis between ROH and sire fertility was performed comparing 300 high-fertility vs. 300 low-fertility bulls. Both the average and sum of ROH length were higher in the low-fertility group. The enrichment of ROH regions in bulls with low fertility was assessed using a Fisher’s exact test. Nine regions were significantly enriched in low-fertility compared to high-fertility bulls. Notably, these regions harbor genes that are closely related to sperm biology and male fertility, including genes exclusively or highly expressed in testis. Conclusions The results of this study can help not only to manage inbreeding in genomic selection programs by designing custom mating schemes, but also to better understand the mechanisms underlying male fertility in dairy cattle.
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Affiliation(s)
- Juan Pablo Nani
- Department of Animal Sciences, University of Florida, 2250 Shealy Drive, Gainesville, FL, 32611, USA.,Estación Experimental Agropecuaria Rafaela, Instituto Nacional de Tecnología Agropecuaria, 22-2300, Rafaela, SF, Argentina
| | - Francisco Peñagaricano
- Department of Animal Sciences, University of Florida, 2250 Shealy Drive, Gainesville, FL, 32611, USA. .,University of Florida Genetics Institute, University of Florida, Gainesville, FL, 32610, USA.
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Abstract
Bacterial Artificial Chromosome (BAC) libraries are a valuable research resource. Any one of the clones in these libraries can carry hundreds of thousands of base pairs of genetic information. Often the entire coding sequence and significant upstream and downstream regions, including regulatory elements, can be found in a single BAC clone. BACs can be put to many uses, such as to study the function of human genes in knockout mice, to drive reporter gene expression in transgenic animals, and for gene discovery. In order to use BACs for experimental purposes it is often desirable to genetically modify them by introducing reporter elements or heterologous cDNA sequences. It is not feasible to use conventional DNA cloning approaches to modify BACs due to their size and complexity, thus a specialized field "recombineering" has developed to modify BAC clones through the use of homologous recombination in bacteria with short homology regions. Genetically engineered BACs can then be used in cell culture, mouse, or rat models to study cancer, neurology, and genetics.
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Abstract
The autosomal-recessive cerebellar ataxias comprise more than half of the known genetic forms of ataxia and represent an extensive group of clinically heterogeneous disorders that can occur at any age but whose onset is typically prior to adulthood. In addition to ataxia, patients often present with polyneuropathy and clinical symptoms outside the nervous system. The most common of these diseases is Friedreich ataxia, caused by mutation of the frataxin gene, but recent advances in genetic analysis have greatly broadened the ever-expanding number of causative genes to over 50. In this review, the clinical neurogenetics of the recessive cerebellar ataxias will be discussed, including updates on recently identified novel ataxia genes, advancements in unraveling disease-specific molecular pathogenesis leading to ataxia, potential treatments under development, technologic improvements in diagnostic testing such as clinical exome sequencing, and what the future holds for clinicians and geneticists.
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Affiliation(s)
- Brent L Fogel
- Program in Neurogenetics, Departments of Neurology and Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, United States.
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McMackin MZ, Henderson CK, Cortopassi GA. Neurobehavioral deficits in the KIKO mouse model of Friedreich's ataxia. Behav Brain Res 2017; 316:183-188. [PMID: 27575947 PMCID: PMC5051948 DOI: 10.1016/j.bbr.2016.08.053] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 08/24/2016] [Accepted: 08/25/2016] [Indexed: 11/30/2022]
Abstract
Friedreich's Ataxia (FA) is a pediatric neurodegenerative disease whose clinical presentation includes ataxia, muscle weakness, and peripheral sensory neuropathy. The KIKO mouse is an animal model of FA with frataxin deficiency first described in 2002, but neurobehavioral deficits have never been described in this model. The identification of robust neurobehavioral deficits in KIKO mice could support the testing of drugs for FA, which currently has no approved therapy. We tested 13 neurobehavioral tasks to identify a robust KIKO phenotype: Open Field, Grip Strength Test(s), Cylinder, Skilled Forelimb Grasp Task(s), Treadmill Endurance, Locotronic Motor Coordination, Inverted Screen, Treadscan, and Von Frey. Of these, Inverted Screen, Treadscan and Von Frey produced significant neurobehavioral deficits at >8 months of age, and relate to the clinically relevant endpoints of muscle strength and endurance, gait ataxia, and peripheral insensitivity. Thus we identify robust phenotypic measures related to Friedreich's ataxia clinical endpoints which could be used to test effectiveness of potential drug therapy.
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Affiliation(s)
- Marissa Z McMackin
- Department of Molecular Biosciences, University of California, Davis, CA 95616, USA
| | - Chelsea K Henderson
- Department of Molecular Biosciences, University of California, Davis, CA 95616, USA
| | - Gino A Cortopassi
- Department of Molecular Biosciences, University of California, Davis, CA 95616, USA.
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Pérez-Luz S, Gimenez-Cassina A, Fernández-Frías I, Wade-Martins R, Díaz-Nido J. Delivery of the 135 kb human frataxin genomic DNA locus gives rise to different frataxin isoforms. Genomics 2015; 106:76-82. [PMID: 26027909 DOI: 10.1016/j.ygeno.2015.05.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 05/21/2015] [Accepted: 05/23/2015] [Indexed: 11/25/2022]
Abstract
Friedreich's ataxia (FRDA) is the most common form of hereditary ataxia caused by recessive mutations in the FXN gene. Recent results have indicated the presence of different frataxin isoforms due to alternative gene expression mechanisms. Our previous studies demonstrated the advantages of using high-capacity herpes simplex virus type 1 (HSV-1) amplicon vectors containing the entire FXN genomic locus (iBAC-FXN) as a gene-delivery vehicle capable of ensuring physiologically-regulated and long-term persistence. Here we describe how expression from the 135 kb human FXN genomic locus produces the three frataxin isoforms both in cultured neuronal cells and also in vivo. Moreover, we also observed the correct expression of these frataxin isoforms in patient-derived cells after delivery of the iBAC-FXN. These results lend further support to the potential use of HSV-1 vectors containing entire genomic loci whose expression is mediated by complex transcriptional and posttranscriptional mechanisms for gene therapy applications.
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Affiliation(s)
- S Pérez-Luz
- Departamento Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigación Sanitaria Puerta de Hierro-Majadahonda, Spain
| | | | - I Fernández-Frías
- Departamento Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigación Sanitaria Puerta de Hierro-Majadahonda, Spain
| | | | - J Díaz-Nido
- Departamento Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigación Sanitaria Puerta de Hierro-Majadahonda, Spain.
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