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Guo L, Wang Q, Weng L, Hauser LA, Strawser CJ, Mesaros C, Lynch DR, Blair IA. Characterization of a new N-terminally acetylated extra-mitochondrial isoform of frataxin in human erythrocytes. Sci Rep 2018; 8:17043. [PMID: 30451920 PMCID: PMC6242848 DOI: 10.1038/s41598-018-35346-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 11/02/2018] [Indexed: 01/18/2023] Open
Abstract
Frataxin is a highly conserved protein encoded by the frataxin (FXN) gene. The full-length 210-amino acid form of protein frataxin (1-210; isoform A) expressed in the cytosol of cells rapidly translocates to the mitochondria, where it is converted to the mature form (81-210) by mitochondrial processing peptidase. Mature frataxin (81-210) is a critically important protein because it facilitates the assembly of mitochondrial iron-sulfur cluster protein complexes such as aconitase, lipoate synthase, and succinate dehydrogenases. Decreased expression of frataxin protein is responsible for the devastating rare genetic disease of Friedreich's ataxia. The mitochondrial form of frataxin has long been thought to be present in erythrocytes even though paradoxically, erythrocytes lack mitochondria. We have discovered that erythrocyte frataxin is in fact a novel isoform of frataxin (isoform E) with 135-amino acids and an N-terminally acetylated methionine residue. There is three times as much isoform E in erythrocytes (20.9 ± 6.4 ng/mL) from the whole blood of healthy volunteers (n = 10) when compared with the mature mitochondrial frataxin present in other blood cells (7.1 ± 1.0 ng/mL). Isoform E lacks a mitochondrial targeting sequence and so is distributed to both cytosol and the nucleus when expressed in cultured cells. When extra-mitochondrial frataxin isoform E is expressed in HEK 293 cells, it is converted to a shorter isoform identical to the mature frataxin found in mitochondria, which raises the possibility that it is involved in disease etiology. The ability to specifically quantify extra-mitochondrial and mitochondrial isoforms of frataxin in whole blood will make it possible to readily follow the natural history of diseases such as Friedreich's ataxia and monitor the efficacy of therapeutic interventions.
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Affiliation(s)
- Lili Guo
- Penn SRP Center and Center of Excellence in Environmental Toxicology Center, Department of Systems Pharmacology and Translational Therapeutics Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
- Penn/CHOP Center of Excellence in Friedreich's ataxia, Philadelphia, PA, 19104, United States
| | - Qingqing Wang
- Penn SRP Center and Center of Excellence in Environmental Toxicology Center, Department of Systems Pharmacology and Translational Therapeutics Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
- Penn/CHOP Center of Excellence in Friedreich's ataxia, Philadelphia, PA, 19104, United States
| | - Liwei Weng
- Penn SRP Center and Center of Excellence in Environmental Toxicology Center, Department of Systems Pharmacology and Translational Therapeutics Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Lauren A Hauser
- Penn/CHOP Center of Excellence in Friedreich's ataxia, Philadelphia, PA, 19104, United States
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, United States
- Departments of Pediatrics and Neurology Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Cassandra J Strawser
- Penn/CHOP Center of Excellence in Friedreich's ataxia, Philadelphia, PA, 19104, United States
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, United States
- Departments of Pediatrics and Neurology Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Clementina Mesaros
- Penn SRP Center and Center of Excellence in Environmental Toxicology Center, Department of Systems Pharmacology and Translational Therapeutics Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
- Penn/CHOP Center of Excellence in Friedreich's ataxia, Philadelphia, PA, 19104, United States
| | - David R Lynch
- Penn/CHOP Center of Excellence in Friedreich's ataxia, Philadelphia, PA, 19104, United States
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, United States
- Departments of Pediatrics and Neurology Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Ian A Blair
- Penn SRP Center and Center of Excellence in Environmental Toxicology Center, Department of Systems Pharmacology and Translational Therapeutics Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States.
- Penn/CHOP Center of Excellence in Friedreich's ataxia, Philadelphia, PA, 19104, United States.
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Delgado-Suárez EJ, Selem-Mojica N, Ortiz-López R, Gebreyes WA, Allard MW, Barona-Gómez F, Rubio-Lozano MS. Whole genome sequencing reveals widespread distribution of typhoidal toxin genes and VirB/D4 plasmids in bovine-associated nontyphoidal Salmonella. Sci Rep 2018; 8:9864. [PMID: 29959369 PMCID: PMC6026178 DOI: 10.1038/s41598-018-28169-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 05/23/2018] [Indexed: 01/23/2023] Open
Abstract
Nontyphoidal Salmonella (NTS) is a common pathogen in food-producing animals and a public health concern worldwide. Various NTS serovars may be present in apparently healthy animals. This could result in carcass contamination during the slaughter process leading to human exposure. While most genomic research has focused on Salmonella pathogenesis, little is known on the factors associated with subclinical infections and environmental persistence. We report here the widespread distribution of typhoidal toxin genes (i. e. the cdtB islet, hlyE, taiA), among NTS strains from a beef slaughter operation (n = 39) and from epidemiologically unconnected ground beef (n = 20). These genes were present in 76% of the strains, regardless of serovar, isolation source or geographical location. Moreover, strains that predominated in the slaughterhouse carry plasmid-borne type IV secretion systems (T4SS), which have been linked to persistent infections in numerous pathogens. Population genomics supports clonal dissemination of NTS along the food production chain, highlighting its role as reservoir of genetic variability in the environment. Overall, the study provides a thorough characterization of serovar diversity and genomic features of beef-associated NTS in Mexico. Furthermore, it reveals how common genetic factors could partially explain the emergence and persistence of certain NTS serovars in the beef industry.
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Affiliation(s)
- Enrique Jesús Delgado-Suárez
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Mexico City, 04510, Mexico.
| | - Nelly Selem-Mojica
- Evolution of Metabolic Diversity Laboratory, Unidad de Genómica Avanzada (Langebio), Cinvestav-IPN, Irapuato, 36821, Mexico
| | - Rocío Ortiz-López
- Centro de Investigación y Desarrollo en Ciencias de la Salud, Universidad Autónoma de Nuevo León, Monterrey, 66460, Mexico
- Tecnológico de Monterrey, School of Medicine and Health Sciences, Monterrey, 64710, Mexico
| | | | - Marc W Allard
- Office of Regulatory Science, Center for Food Safety and Applied Nutrition, U. S. Food and Drug Administration, College Park, 20740, USA
| | - Francisco Barona-Gómez
- Evolution of Metabolic Diversity Laboratory, Unidad de Genómica Avanzada (Langebio), Cinvestav-IPN, Irapuato, 36821, Mexico.
| | - María Salud Rubio-Lozano
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Mexico City, 04510, Mexico
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