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Fiorito V, Tolosano E. Unearthing FLVCR1a: tracing the path to a vital cellular transporter. Cell Mol Life Sci 2024; 81:166. [PMID: 38581583 PMCID: PMC10998817 DOI: 10.1007/s00018-024-05205-3] [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] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/08/2024] [Accepted: 03/13/2024] [Indexed: 04/08/2024]
Abstract
The Feline Leukemia Virus Subgroup C Receptor 1a (FLVCR1a) is a member of the SLC49 Major Facilitator Superfamily of transporters. Initially recognized as the receptor for the retrovirus responsible of pure red cell aplasia in cats, nearly two decades since its discovery, FLVCR1a remains a puzzling transporter, with ongoing discussions regarding what it transports and how its expression is regulated. Nonetheless, despite this, the substantial body of evidence accumulated over the years has provided insights into several critical processes in which this transporter plays a complex role, and the health implications stemming from its malfunction. The present review intends to offer a comprehensive overview and a critical analysis of the existing literature on FLVCR1a, with the goal of emphasising the vital importance of this transporter for the organism and elucidating the interconnections among the various functions attributed to this transporter.
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Affiliation(s)
- Veronica Fiorito
- Molecular Biotechnology Center (MBC) "Guido Tarone", Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126, Turin, Italy
| | - Emanuela Tolosano
- Molecular Biotechnology Center (MBC) "Guido Tarone", Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126, Turin, Italy.
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Chiabrando D, Bertino F, Tolosano E. Hereditary Ataxia: A Focus on Heme Metabolism and Fe-S Cluster Biogenesis. Int J Mol Sci 2020; 21:ijms21113760. [PMID: 32466579 PMCID: PMC7312568 DOI: 10.3390/ijms21113760] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 05/21/2020] [Accepted: 05/22/2020] [Indexed: 02/07/2023] Open
Abstract
Heme and Fe-S clusters regulate a plethora of essential biological processes ranging from cellular respiration and cell metabolism to the maintenance of genome integrity. Mutations in genes involved in heme metabolism and Fe-S cluster biogenesis cause different forms of ataxia, like posterior column ataxia and retinitis pigmentosa (PCARP), Friedreich's ataxia (FRDA) and X-linked sideroblastic anemia with ataxia (XLSA/A). Despite great efforts in the elucidation of the molecular pathogenesis of these disorders several important questions still remain to be addressed. Starting with an overview of the biology of heme metabolism and Fe-S cluster biogenesis, the review discusses recent progress in the understanding of the molecular pathogenesis of PCARP, FRDA and XLSA/A, and highlights future line of research in the field. A better comprehension of the mechanisms leading to the degeneration of neural circuity responsible for balance and coordinated movement will be crucial for the therapeutic management of these patients.
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Lee J, Scanga HL, Dansingani KK, Taubenslag KJ, Zlotcavitch L, Chauhan BK, Sylvester CL, Morton DH, Nischal KK. Clinical and imaging characteristics of posterior column ataxia with retinitis pigmentosa with a specific FLVCR1 mutation. Ophthalmic Genet 2018; 39:735-740. [DOI: 10.1080/13816810.2018.1547913] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Jennifer Lee
- Department of Pediatric Ophthalmology, Strabismus, and Adult Motility, Children’s Hospital of Pittsburgh of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Hannah L. Scanga
- Department of Pediatric Ophthalmology, Strabismus, and Adult Motility, Children’s Hospital of Pittsburgh of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Kunal K. Dansingani
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Kenneth J. Taubenslag
- Department of Pediatric Ophthalmology, Strabismus, and Adult Motility, Children’s Hospital of Pittsburgh of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Leonid Zlotcavitch
- Department of Pediatric Ophthalmology, Strabismus, and Adult Motility, Children’s Hospital of Pittsburgh of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Bharesh K. Chauhan
- Department of Pediatric Ophthalmology, Strabismus, and Adult Motility, Children’s Hospital of Pittsburgh of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Christin L. Sylvester
- Department of Pediatric Ophthalmology, Strabismus, and Adult Motility, Children’s Hospital of Pittsburgh of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - D. Holmes Morton
- Pediatrician, Central Pennsylvania Clinic for Special Children and Adults, Belleville, Pennsylvania, USA
- Department of Pediatrics, Children’s Hospital of Pittsburgh of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Ken K. Nischal
- Department of Pediatric Ophthalmology, Strabismus, and Adult Motility, Children’s Hospital of Pittsburgh of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
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Chiabrando D, Castori M, di Rocco M, Ungelenk M, Gießelmann S, Di Capua M, Madeo A, Grammatico P, Bartsch S, Hübner CA, Altruda F, Silengo L, Tolosano E, Kurth I. Mutations in the Heme Exporter FLVCR1 Cause Sensory Neurodegeneration with Loss of Pain Perception. PLoS Genet 2016; 12:e1006461. [PMID: 27923065 PMCID: PMC5140052 DOI: 10.1371/journal.pgen.1006461] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [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: 04/27/2016] [Accepted: 11/04/2016] [Indexed: 12/12/2022] Open
Abstract
Pain is necessary to alert us to actual or potential tissue damage. Specialized nerve cells in the body periphery, so called nociceptors, are fundamental to mediate pain perception and humans without pain perception are at permanent risk for injuries, burns and mutilations. Pain insensitivity can be caused by sensory neurodegeneration which is a hallmark of hereditary sensory and autonomic neuropathies (HSANs). Although mutations in several genes were previously associated with sensory neurodegeneration, the etiology of many cases remains unknown. Using next generation sequencing in patients with congenital loss of pain perception, we here identify bi-allelic mutations in the FLVCR1 (Feline Leukemia Virus subgroup C Receptor 1) gene, which encodes a broadly expressed heme exporter. Different FLVCR1 isoforms control the size of the cytosolic heme pool required to sustain metabolic activity of different cell types. Mutations in FLVCR1 have previously been linked to vision impairment and posterior column ataxia in humans, but not to HSAN. Using fibroblasts and lymphoblastoid cell lines from patients with sensory neurodegeneration, we here show that the FLVCR1-mutations reduce heme export activity, enhance oxidative stress and increase sensitivity to programmed cell death. Our data link heme metabolism to sensory neuron maintenance and suggest that intracellular heme overload causes early-onset degeneration of pain-sensing neurons in humans. Hereditary Sensory and Autonomic Neuropathy (HSAN) is a genetic disorder mainly characterized by the impairment of sensory neurons, which transmit information about sensations such as pain, temperature and touch. Therefore, unintentional self-injury, leading to ulcers and eventually amputations are common in affected individuals. Although mutations in several genes were previously associated with sensory neurodegeneration and pain insensitivity, the etiology of many cases remains unknown. We here identify mutations in the heme exporter protein FLVCR1 in patients with congenital inability to experience pain. We showed that FLVCR1 mutations results in reduced heme export activity, enhanced oxidative stress and increased sensitivity to programmed cell death. These data assign a surprising role for heme to sensory neuron maintenance.
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Affiliation(s)
- Deborah Chiabrando
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy
- * E-mail: (DC); (ET); (IK)
| | - Marco Castori
- Unit of Medical Genetics, Department of Molecular Medicine, Sapienza University, San Camillo-Forlanini Hospital, Rome, Italy
| | - Maja di Rocco
- Unit of Rare Diseases, Department of Pediatrics, Gaslini Institute, Genoa, Italy
| | - Martin Ungelenk
- Institute of Human Genetics, Jena University Hospital, Friedrich-Schiller-University Jena, Jena, Germany
| | - Sebastian Gießelmann
- Institute of Human Genetics, Jena University Hospital, Friedrich-Schiller-University Jena, Jena, Germany
- Institute of Human Genetics, Uniklinik RWTH Aachen, Aachen, Germany
| | - Matteo Di Capua
- Unit of Neurophysiopathology, Department of Neuroscience, Bambino Gesù Children's Hospital, Rome, Italy
| | - Annalisa Madeo
- Unit of Rare Diseases, Department of Pediatrics, Gaslini Institute, Genoa, Italy
| | - Paola Grammatico
- Unit of Medical Genetics, Department of Molecular Medicine, Sapienza University, San Camillo-Forlanini Hospital, Rome, Italy
| | - Sophie Bartsch
- Institute of Human Genetics, Jena University Hospital, Friedrich-Schiller-University Jena, Jena, Germany
| | - Christian A. Hübner
- Institute of Human Genetics, Jena University Hospital, Friedrich-Schiller-University Jena, Jena, Germany
| | - Fiorella Altruda
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy
| | - Lorenzo Silengo
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy
| | - Emanuela Tolosano
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy
- * E-mail: (DC); (ET); (IK)
| | - Ingo Kurth
- Institute of Human Genetics, Jena University Hospital, Friedrich-Schiller-University Jena, Jena, Germany
- Institute of Human Genetics, Uniklinik RWTH Aachen, Aachen, Germany
- * E-mail: (DC); (ET); (IK)
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Abstract
Hereditary ataxias (HA) encompass an increasing number of degenerative disorders characterized by progressive cerebellar ataxia usually accompanied by extracerebellar semeiology including peripheral nerve involvement. Classically, HA were classified according to their pathological hallmark comprising three main forms: (1) spinal form predominantly with degeneration of spinocerebellar tracts, posterior columns, and pyramidal tracts (Friedreich's ataxia, FA); (2) olivopontocerebellar atrophy (OPCA); and (3) cortical cerebellar atrophy (CCA). In the 1980s Harding proposed a clinico-genetic classification based upon age of onset, modality of transmission, and clinical semeiology. The main categories in this classification were as follows: (1) early onset cerebellar ataxia (EOCA) with age of onset below 25 years and usually with autosomal recessive (AR) transmission (this group encompasses FA and syndromes different from FA); (2) autosomal dominant cerebellar ataxia (ADCA) with adult onset and with either cerebellar-plus syndrome or pure cerebellar semeiology; and (3) idiopathic late onset onset cerebellar ataxia (ILOCA). With the advent of molecular genetics, the nosology of HA has been in a state of constant flux. At present EOCA comprises at least 17 genotypes (designated with the acronym of ARCA derived from AR cerebellar ataxia), whereas under the umbrella of ADCA 30 genotypes have been reported. In this chapter we will review peripheral nerve involvement in classical pathological entities (OPCA and CCA), ARCA, ADCA, and ILOCA paying special attention to the most prevalent syndromes in each category. As a general rule, nerve involvement is relatively common in any form of ataxia except ILOCA, the most common pattern being either sensory or sensorimotor neuronopathy with a dying-back process. An exception to this rule is AR spastic ataxia of Charlevoix-Saguenay where nerve conduction studies show the characteristic pattern of intermediate neuropathy implying that sacsin mutation causes both axonal and Schwann cell dysfunction.
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Affiliation(s)
- José Berciano
- Department of Neurology and Clinical Neurophysiology, University Hospital "Marqués de Valdecilla (IFIMAV)", University of Cantabria and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Santander, Spain.
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Ishiura H, Fukuda Y, Mitsui J, Nakahara Y, Ahsan B, Takahashi Y, Ichikawa Y, Goto J, Sakai T, Tsuji S. Posterior column ataxia with retinitis pigmentosa in a Japanese family with a novel mutation in FLVCR1. Neurogenetics 2011; 12:117-21. [PMID: 21267618 DOI: 10.1007/s10048-010-0271-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [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: 12/02/2010] [Accepted: 12/03/2010] [Indexed: 11/26/2022]
Abstract
Posterior column ataxia with retinitis pigmentosa (PCARP) is an autosomal recessive neurodegenerative disorder characterized by retinitis pigmentosa and sensory ataxia. Previous studies of PCARP in two families showed a linkage to 1q31-q32. However, detailed investigations on the clinical presentations as well as molecular genetics of PCARP have been limited. Here, we describe a Japanese consanguineous family with PCARP. Two affected siblings suffered from childhood-onset retinitis pigmentosa and slowly progressive sensory ataxia. They also showed mild mental retardation, which has not been described in patients with PCARP. Parametric linkage analysis using high-density single nucleotide polymorphism arrays supported a linkage to the same locus. Target capture and high-throughput sequencing technologies revealed a novel homozygous c.1477G>C (G493R) mutation in FLVCR1, which cosegregated with the disease. A recent study has identified three independent mutations in FLVCR1 in the original and other families. Our results further confirmed that PCARP is caused by mutations in FLVCR1.
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Affiliation(s)
- Hiroyuki Ishiura
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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Rajadhyaksha AM, Elemento O, Puffenberger EG, Schierberl KC, Xiang JZ, Putorti ML, Berciano J, Poulin C, Brais B, Michaelides M, Weleber RG, Higgins JJ. Mutations in FLVCR1 cause posterior column ataxia and retinitis pigmentosa. Am J Hum Genet 2010; 87:643-54. [PMID: 21070897 DOI: 10.1016/j.ajhg.2010.10.013] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [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: 09/13/2010] [Revised: 10/14/2010] [Accepted: 10/14/2010] [Indexed: 11/19/2022] Open
Abstract
The study of inherited retinal diseases has advanced our knowledge of the cellular and molecular mechanisms involved in sensory neural signaling. Dysfunction of two specific sensory modalities, vision and proprioception, characterizes the phenotype of the rare, autosomal-recessive disorder posterior column ataxia and retinitis pigmentosa (PCARP). Using targeted DNA capture and high-throughput sequencing, we analyzed the entire 4.2 Mb candidate sequence on chromosome 1q32 to find the gene mutated in PCARP in a single family. Employing comprehensive bioinformatic analysis and filtering, we identified a single-nucleotide coding variant in the feline leukemia virus subgroup C cellular receptor 1 (FLVCR1), a gene encoding a heme-transporter protein. Sanger sequencing confirmed the FLVCR1 mutation in this family and identified different homozygous missense mutations located within the protein's transmembrane channel segment in two other unrelated families with PCARP. To determine whether the selective pathologic features of PCARP correlated with FLVCR1 expression, we examined wild-type mouse Flvcr1 mRNA levels in the posterior column of the spinal cord and the retina via quantitative real-time reverse-transcriptase PCR. The Flvcr1 mRNA levels were most abundant in the retina, followed by the posterior column of the spinal cord and other brain regions. These results suggest that aberrant FLVCR1 causes a selective degeneration of a subpopulation of neurons in the retina and the posterior columns of the spinal cord via dysregulation of heme or iron homeostasis. This finding broadens the molecular basis of sensory neural signaling to include common mechanisms that involve proprioception and vision.
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Affiliation(s)
- Anjali M Rajadhyaksha
- Department of Pediatrics, New York Presbyterian Hospital, Weill Cornell Medical College, New York, 10065, USA
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Kastrup O, Timman D, Diener HC. Isolated degeneration of the posterior column as a distinct entity--a clinical and electrophysiologic follow-up study. Clin Neurol Neurosurg 2010; 112:209-12. [PMID: 20018441 DOI: 10.1016/j.clineuro.2009.11.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 08/21/2009] [Accepted: 11/18/2009] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The aim of the study was to better describe the long term clinical course and electrophysiologic and radiologic findings in isolated degeneration of the posterior column. METHODS Four patients with the presenting symptoms of a progressive tabetic ataxia were followed up clinically and electrophysiologically over up to 15 years between 1997 and 2008. They received standardized neurological examinations, electrophysiologic testing with SEP, MEP, NCV, EMG, autonomic testing and cardiac evaluation, head and spine MRI, laboratory evaluation including CSF analysis. RESULTS Progressive gait ataxia due to pallhypasthesia and loss of position sense with areflexia remained the only symptoms. Pes cavus deformity was a notable clinical feature in all cases. There was no involvement of other systems and all patients remained fully ambulatory. There was no cardiac involvement. Electrophysiology was characterized by absent cortical tibial SEP with normal lumbar complexes and normal nerve conduction studies and transcortical magnetic stimulation as well as sympathetic skin response. MRI of the cord was normal. Laboratory analysis and CSF were unrevealing. CONCLUSION Isolated degeneration of the posterior column is a rare condition with a clinically benign course without progression involving other systems and characteristic electrophysiologic findings (isolated loss of cortical tibial-SEP with normal lumbar leads). Pes cavus deformity seems to be an unusual but typical clinical feature. The etiology is most likely a sporadic degenerative disease of the cord.
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Abstract
Autosomal recessive cerebellar ataxias (ARCA) are a heterogeneous group of rare neurological disorders involving both central and peripheral nervous system, and in some case other systems and organs, and characterized by degeneration or abnormal development of cerebellum and spinal cord, autosomal recessive inheritance and, in most cases, early onset occurring before the age of 20 years. This group encompasses a large number of rare diseases, the most frequent in Caucasian population being Friedreich ataxia (estimated prevalence 2–4/100,000), ataxia-telangiectasia (1–2.5/100,000) and early onset cerebellar ataxia with retained tendon reflexes (1/100,000). Other forms ARCA are much less common. Based on clinicogenetic criteria, five main types ARCA can be distinguished: congenital ataxias (developmental disorder), ataxias associated with metabolic disorders, ataxias with a DNA repair defect, degenerative ataxias, and ataxia associated with other features. These diseases are due to mutations in specific genes, some of which have been identified, such as frataxin in Friedreich ataxia, α-tocopherol transfer protein in ataxia with vitamin E deficiency (AVED), aprataxin in ataxia with oculomotor apraxia (AOA1), and senataxin in ataxia with oculomotor apraxia (AOA2). Clinical diagnosis is confirmed by ancillary tests such as neuroimaging (magnetic resonance imaging, scanning), electrophysiological examination, and mutation analysis when the causative gene is identified. Correct clinical and genetic diagnosis is important for appropriate genetic counseling and prognosis and, in some instances, pharmacological treatment. Due to autosomal recessive inheritance, previous familial history of affected individuals is unlikely. For most ARCA there is no specific drug treatment except for coenzyme Q10 deficiency and abetalipoproteinemia.
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Affiliation(s)
- Francesc Palau
- Genetics and Molecular Medicine Unit, Instituto de Biomedicina, CSIC, Jaume Roig, 11 46010 Valencia, Spain
- Centre for Biomedical Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Valencia, Spain
| | - Carmen Espinós
- Genetics and Molecular Medicine Unit, Instituto de Biomedicina, CSIC, Jaume Roig, 11 46010 Valencia, Spain
- Centre for Biomedical Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Valencia, Spain
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Abstract
Sensory neuron diseases (SND) are a distinct subgroup of peripheral-nervous-system diseases, first acknowledged in 1948. Acquired SND have a subacute or chronic course and are associated with systemic immune-mediated diseases, vitamin intoxication or deficiency, neurotoxic drugs, and life-threatening diseases such as cancer. SND are commonly idiopathic but can be genetic diseases; the latter tend to involve subtypes of sensory neurons and are associated with certain clinical pictures. The loss of sensory neurons in dorsal root ganglia causes the degeneration of short and long peripheral axons and central sensory projections in the posterior columns. This pathological process leads to a pattern of sensory nerve degeneration that is not length dependent and explains distinct clinical and neurophysiological abnormalities. Here we propose a comprehensive approach to the diagnosis of acquired and hereditary SND and discuss clinical, genetic, neurophysiological, neuroradiological, and neuropathological assessments.
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Affiliation(s)
- Angelo Sghirlanzoni
- Neuro-Oncology Unit, National Neurological Institute Carlo Besta, Milan, Italy
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