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Cheng J, Yao J, Zhao S, Fu L, Zhang L, Jiang J. A riboflavin transporter deficiency presenting as pure red cell aplasia: a pediatric case report. Front Pediatr 2024; 12:1391245. [PMID: 38694724 PMCID: PMC11061399 DOI: 10.3389/fped.2024.1391245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Accepted: 04/04/2024] [Indexed: 05/04/2024] Open
Abstract
Introduction Riboflavin transporter deficiency (RTD) is a rare genetic disorder that affects riboflavin transport, leading to impaired red blood cell production and resulting in pure red cell aplasia. Recognizing and understanding its clinical manifestations, diagnosis, and management is important. Case presentation A 2-year-old patient presented with pure red cell aplasia as the primary symptom of RTD. After confirming the diagnosis, rapid reversal of anemia was achieved after high-dose riboflavin treatment. Conclusion RTD often has an insidious onset, and neurological symptoms appear gradually as the disease progresses, making it prone to misdiagnosis. Genetic testing and bone marrow biopsy can confirm the diagnosis.
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Affiliation(s)
| | | | | | | | | | - Jin Jiang
- Department of Hematology, National Center for Children’s Health, Beijing Children’s Hospital, Capital Medical University, Beijing, China
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2
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Colasuonno F, Marioli C, Tartaglia M, Bertini E, Compagnucci C, Moreno S. New Insights into the Neurodegeneration Mechanisms Underlying Riboflavin Transporter Deficiency (RTD): Involvement of Energy Dysmetabolism and Cytoskeletal Derangement. Biomedicines 2022; 10:biomedicines10061329. [PMID: 35740351 PMCID: PMC9219947 DOI: 10.3390/biomedicines10061329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/26/2022] [Accepted: 05/30/2022] [Indexed: 01/18/2023] Open
Abstract
Riboflavin transporter deficiency (RTD) is a rare genetic disorder characterized by motor, sensory and cranial neuropathy. This childhood-onset neurodegenerative disease is caused by biallelic pathogenic variants in either SLC52A2 or SLC52A3 genes, resulting in insufficient supply of riboflavin (vitamin B2) and consequent impairment of flavoprotein-dependent metabolic pathways. Current therapy, empirically based high-dose riboflavin supplementation, ameliorates the progression of the disease, even though response to treatment is variable and partial. Recent studies have highlighted concurrent pathogenic contribution of cellular energy dysmetabolism and cytoskeletal derangement. In this context, patient specific RTD models, based on induced pluripotent stem cell (iPSC) technology, have provided evidence of redox imbalance, involving mitochondrial and peroxisomal dysfunction. Such oxidative stress condition likely causes cytoskeletal perturbation, associated with impaired differentiation of RTD motor neurons. In this review, we discuss the most recent findings obtained using different RTD models. Relevantly, the integration of data from innovative iPSC-derived in vitro models and invertebrate in vivo models may provide essential information on RTD pathophysiology. Such novel insights are expected to suggest custom therapeutic strategies, especially for those patients unresponsive to high-dose riboflavin treatments.
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Affiliation(s)
- Fiorella Colasuonno
- Genetics and Rare Diseases Research Division, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (F.C.); (C.M.); (M.T.); (E.B.)
- Department of Science, LIME, University Roma Tre, 00165 Rome, Italy
| | - Chiara Marioli
- Genetics and Rare Diseases Research Division, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (F.C.); (C.M.); (M.T.); (E.B.)
- Department of Science, LIME, University Roma Tre, 00165 Rome, Italy
| | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (F.C.); (C.M.); (M.T.); (E.B.)
| | - Enrico Bertini
- Genetics and Rare Diseases Research Division, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (F.C.); (C.M.); (M.T.); (E.B.)
| | - Claudia Compagnucci
- Genetics and Rare Diseases Research Division, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (F.C.); (C.M.); (M.T.); (E.B.)
- Correspondence: (C.C.); (S.M.)
| | - Sandra Moreno
- Department of Science, LIME, University Roma Tre, 00165 Rome, Italy
- Correspondence: (C.C.); (S.M.)
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3
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Electrodiagnostic Findings in Riboflavin Transporter Deficiency Type 2. J Clin Neuromuscul Dis 2022; 23:205-209. [PMID: 35608644 DOI: 10.1097/cnd.0000000000000390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
ABSTRACT We present the electrodiagnostic findings in a case of a 3-year-old girl presenting with sensory ataxia, gait disturbance, and visual-auditory disturbance with a genetically confirmed diagnosis of riboflavin transporter deficiency type 2 (RTD2). She carries a homozygous mutation in the SLC52A2 gene, c.1016T>C (p.Leu339Pro). Her testing demonstrates a non-length-dependent axonal sensorimotor polyneuropathy affecting predominantly the upper extremities with active denervation of the distal muscles of both arms. It is important to highlight these findings because most genetic neuropathies have a length-dependent pattern of involvement, affecting the distal legs before the arms. The electrodiagnostic findings in RTD2 have not been previously well described. These electrodiagnostic findings are in agreement with the typical clinical phenotype of RTD2, which affects the upper limbs and bulbar muscles more than the lower extremities.
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4
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Liu Z, Peng Q, Li J, Rao C, Lu X. BVVLS2 overlooked for 3 years in a pediatric patient caused by novel compound heterozygous mutations in SLC52A2 gene. Clin Chim Acta 2021; 523:402-406. [PMID: 34737166 DOI: 10.1016/j.cca.2021.10.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/22/2021] [Accepted: 10/25/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND Brown-Vialetto-Van Laere syndrome-2 (BVVLS2) is a rare autosomal recessive neurological disorder caused by mutations in the SLC52A2 gene, which is characterized by early childhood onset of sensorineural hearing loss, bulbar palsy, peripheral neuropathy, and respiratory insufficiency. We aimed to investigate the genetic cause of a 4-year-old boy who suffered from BVVLS2 whose initial presentation was severe normocytic anemia and had been overlooked for three years in a local hospital. He was misdiagnosed with pure red cell aplasia (PRCA) and treated with hormones and chemotherapy drugs, but there was no obvious effect. METHODS The targeted capture of 927 genes associated with neuromuscular disorders and next-generation sequencing were performed. Sanger sequencing was employed to verify the variant mutations. RESULTS The proband was found to be heterozygous for c.350T > C (p.L117P) in exon 3 and c.1135_1137delTGG (p.W379del) in exon 5 of SLC52A2 gene. His anemia and neurological symptoms improved significantly after treatment with low dose oral riboflavin. CONCLUSIONS This study expands the mutational spectrum of SLC52A2 and phenotypic spectrum of BVVLS2, which provides a foundation for further investigations elucidating the SLC52A2 related mechanisms of BVVLS2. A low-dosage of riboflavin supplementation was used to obtain good curative effect, which provides further future references for the clinical treatments of BVVLS.
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Affiliation(s)
- Ziqiang Liu
- Child Healthcare Department, Dongguan Children's Hospital, Dongguan, Guangdong, China
| | - Qi Peng
- Laboratory Department, Dongguan Children's Hospital, Dongguan, Guangdong, China; Department of Medical and Molecular Genetics, Dongguan Institute of Pediatrics, Dongguan, Guangdong, China; Key Laboratory for Children's Genetics and Infectious Diseases of Dongguan, Dongguan, Guangdong, China
| | - Jianwei Li
- Department of Neurology, Dongguan Children's Hospital, Dongguan, Guangdong, China
| | - Chunbao Rao
- Laboratory Department, Dongguan Children's Hospital, Dongguan, Guangdong, China; Department of Medical and Molecular Genetics, Dongguan Institute of Pediatrics, Dongguan, Guangdong, China; Key Laboratory for Children's Genetics and Infectious Diseases of Dongguan, Dongguan, Guangdong, China
| | - Xiaomei Lu
- Laboratory Department, Dongguan Children's Hospital, Dongguan, Guangdong, China; Department of Medical and Molecular Genetics, Dongguan Institute of Pediatrics, Dongguan, Guangdong, China; Key Laboratory for Children's Genetics and Infectious Diseases of Dongguan, Dongguan, Guangdong, China.
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Leone P, Tolomeo M, Piancone E, Puzzovio PG, De Giorgi C, Indiveri C, Di Schiavi E, Barile M. Mimicking human riboflavin responsive neuromuscular disorders by silencing flad-1 gene in C. elegans: Alteration of vitamin transport and cholinergic transmission. IUBMB Life 2021; 74:672-683. [PMID: 34558787 PMCID: PMC9292511 DOI: 10.1002/iub.2553] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 08/14/2021] [Accepted: 08/30/2021] [Indexed: 01/01/2023]
Abstract
Riboflavin (Rf), or vitamin B2, is the precursor of FMN and FAD, redox cofactors of several dehydrogenases involved in energy metabolism, redox balance and other cell regulatory processes. FAD synthase, coded by FLAD1 gene in humans, is the last enzyme in the pathway converting Rf into FAD. Mutations in FLAD1 gene are responsible for neuromuscular disorders, in some cases treatable with Rf. In order to mimic these disorders, the Caenorhabditis elegans (C. elegans) gene orthologue of FLAD1 (flad‐1) was silenced in a model strain hypersensitive to RNA interference in nervous system. Silencing flad‐1 resulted in a significant decrease in total flavin content, paralleled by a decrease in the level of the FAD‐dependent ETFDH protein and by a secondary transcriptional down‐regulation of the Rf transporter 1 (rft‐1) possibly responsible for the total flavin content decrease. Conversely an increased ETFDH mRNA content was found. These biochemical changes were accompanied by significant phenotypical changes, including impairments of fertility and locomotion due to altered cholinergic transmission, as indicated by the increased sensitivity to aldicarb. A proposal is made that neuronal acetylcholine production/release is affected by alteration of Rf homeostasis. Rf supplementation restored flavin content, increased rft‐1 transcript levels and eliminated locomotion defects. In this aspect, C. elegans could provide a low‐cost animal model to elucidate the molecular rationale for Rf therapy in human Rf responsive neuromuscular disorders and to screen other molecules with therapeutic potential.
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Affiliation(s)
- Piero Leone
- Department of Biosciences, Biotechnology, and Biopharmaceutics, University of Bari, Bari, Italy
| | - Maria Tolomeo
- Department of Biosciences, Biotechnology, and Biopharmaceutics, University of Bari, Bari, Italy
| | - Elisabetta Piancone
- Department of Biosciences, Biotechnology, and Biopharmaceutics, University of Bari, Bari, Italy
| | - Pier Giorgio Puzzovio
- Faculty of Medicine, Pharmacology and Experimental Therapeutics Unit, Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Carla De Giorgi
- Department of Biosciences, Biotechnology, and Biopharmaceutics, University of Bari, Bari, Italy
| | - Cesare Indiveri
- Department DiBEST (Biologia, Ecologia, Scienze della Terra), Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Arcavacata di Rende, Italy
| | - Elia Di Schiavi
- Institute of Biosciences and Bioresources (IBBR) CNR, Naples, Italy
| | - Maria Barile
- Department of Biosciences, Biotechnology, and Biopharmaceutics, University of Bari, Bari, Italy
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Console L, Tolomeo M, Cosco J, Massey K, Barile M, Indiveri C. Impact of natural mutations on the riboflavin transporter 2 and their relevance to human riboflavin transporter deficiency 2. IUBMB Life 2021; 74:618-628. [PMID: 34428344 DOI: 10.1002/iub.2541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/07/2021] [Accepted: 07/29/2021] [Indexed: 12/28/2022]
Abstract
Riboflavin transporter deficiency 2 (RTD2) is a rare neurological disorder caused by mutations in the Solute carrier family 52 member 2 (Slc52a2) gene encoding human riboflavin transporter 2 (RFVT2). This transporter is ubiquitously expressed and mediates tissue distribution of riboflavin, a water-soluble vitamin that, after conversion into FMN and FAD, plays pivotal roles in carbohydrate, protein, and lipid metabolism. The 3D structure of RFVT2 has been constructed by homology modeling using three different templates that are equilibrative nucleoside transporter 1 (ENT1), Fucose: proton symporter, and glucose transporter type 5 (GLUT5). The structure has been validated by several approaches. All known point mutations of RFVT2, associated with RTD2, have been localized in the protein 3D model. Six of these mutations have been introduced in the recombinant protein for functional characterization. The mutants W31S, S52F, S128L, L312P, C325G, and M423V have been expressed in E. coli, purified, and reconstituted into proteoliposomes for transport assay. All the mutants showed impairment of function. The Km for riboflavin of the mutants increased from about 3 to 9 times with respect to that of WT, whereas Vmax was only marginally affected. This agrees with the improved outcome of most RTD2 patients after administration of high doses of riboflavin.
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Affiliation(s)
- Lara Console
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Arcavacata di Rende, Italy
| | - Maria Tolomeo
- Department of Biosciences, Biotechnology, and Biopharmaceutics, University of Bari, Bari, Italy
| | - Jessica Cosco
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Arcavacata di Rende, Italy
| | | | - Maria Barile
- Department of Biosciences, Biotechnology, and Biopharmaceutics, University of Bari, Bari, Italy
| | - Cesare Indiveri
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Arcavacata di Rende, Italy
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Alteration of Flavin Cofactor Homeostasis in Human Neuromuscular Pathologies. Methods Mol Biol 2021; 2280:275-295. [PMID: 33751442 DOI: 10.1007/978-1-0716-1286-6_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The aim of this short review chapter is to provide a brief summary of the relevance of riboflavin (Rf or vitamin B2) and its derived cofactors flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) for human neuromuscular bioenergetics.Therefore, as a completion of this book we would like to summarize what kind of human pathologies could derive from genetic disturbances of Rf transport, flavin cofactor synthesis and delivery to nascent apoflavoproteins, as well as by alteration of vitamin recycling during protein turnover.
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8
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Colasuonno F, Bertini E, Tartaglia M, Compagnucci C, Moreno S. Mitochondrial Abnormalities in Induced Pluripotent Stem Cells-Derived Motor Neurons from Patients with Riboflavin Transporter Deficiency. Antioxidants (Basel) 2020; 9:E1252. [PMID: 33317017 PMCID: PMC7763948 DOI: 10.3390/antiox9121252] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 11/30/2020] [Accepted: 12/03/2020] [Indexed: 12/31/2022] Open
Abstract
Riboflavin transporter deficiency (RTD) is a childhood-onset neurodegenerative disorder characterized by sensorineural deafness and motor neuron degeneration. Since riboflavin plays key functions in biological oxidation-reduction reactions, energy metabolism pathways involving flavoproteins are affected in RTD. We recently generated induced pluripotent stem cell (iPSC) lines from affected individuals as an in vitro model of the disease and documented mitochondrial impairment in these cells, dramatically impacting cell redox status. This work extends our study to motor neurons (MNs), i.e., the cell type most affected in patients with RTD. Altered intracellular distribution of mitochondria was detected by confocal microscopic analysis (following immunofluorescence for superoxide dismutase 2 (SOD2), as a dual mitochondrial and antioxidant marker), and βIII-Tubulin, as a neuronal marker. We demonstrate significantly lower SOD2 levels in RTD MNs, as compared to their healthy counterparts. Mitochondrial ultrastructural abnormalities were also assessed by focused ion beam/scanning electron microscopy. Moreover, we investigated the effects of combination treatment using riboflavin and N-acetylcysteine, which is a widely employed antioxidant. Overall, our findings further support the potential of patient-specific RTD models and provide evidence of mitochondrial alterations in RTD-related iPSC-derived MNs-emphasizing oxidative stress involvement in this rare disease. We also provide new clues for possible therapeutic strategies aimed at correcting mitochondrial defects, based on the use of antioxidants.
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Affiliation(s)
- Fiorella Colasuonno
- Department of Science, LIME, University of Roma Tre, 00146 Rome, Italy;
- Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy;
| | - Enrico Bertini
- Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Department of Neuroscience, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy;
| | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy;
| | - Claudia Compagnucci
- Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy;
| | - Sandra Moreno
- Department of Science, LIME, University of Roma Tre, 00146 Rome, Italy;
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9
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Pillai NR, Amin H, Gijavanekar C, Liu N, Issaq N, Broniowska KA, Bertuch AA, Sutton VR, Elsea SH, Scaglia F. Hematologic presentation and the role of untargeted metabolomics analysis in monitoring treatment for riboflavin transporter deficiency. Am J Med Genet A 2020; 182:2781-2787. [PMID: 32909658 DOI: 10.1002/ajmg.a.61851] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 08/02/2020] [Accepted: 08/15/2020] [Indexed: 12/21/2022]
Abstract
Riboflavin transporter deficiency (RTD) (MIM #614707) is a neurogenetic disorder with its most common manifestations including sensorineural hearing loss, peripheral neuropathy, respiratory insufficiency, and bulbar palsy. Here, we present a 2-year-old boy whose initial presentation was severe macrocytic anemia necessitating multiple blood transfusions and intermittent neutropenia; he subsequently developed ataxia and dysarthria. Trio-exome sequencing detected compound heterozygous variants in SLC52A2 that were classified as pathogenic and a variant of uncertain significance. Bone marrow evaluation demonstrated megaloblastic changes. Notably, his anemia and neutropenia resolved after treatment with oral riboflavin, thus expanding the clinical phenotype of this disorder. We reiterate the importance of starting riboflavin supplementation in a young child who presents with macrocytic anemia and neurological features while awaiting biochemical and genetic work up. We detected multiple biochemical abnormalities with the help of untargeted metabolomics analysis associated with abnormal flavin adenine nucleotide function which normalized after treatment, emphasizing the reversible pathomechanisms involved in this disorder. The utility of untargeted metabolomics analysis to monitor the effects of riboflavin supplementation in RTD has not been previously reported.
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Affiliation(s)
- Nishitha R Pillai
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.,Texas Children's Hospital, Houston, Texas, USA
| | - Hitha Amin
- Texas Children's Hospital, Houston, Texas, USA.,Department of Neurology, Baylor College of Medicine, Houston, Texas, USA
| | | | - Ning Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Niveen Issaq
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, USA
| | | | - Alison A Bertuch
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.,Texas Children's Hospital, Houston, Texas, USA.,Department of Pediatrics, Hematology/Oncology, Baylor College of Medicine, Houston, Texas, USA
| | - V Reid Sutton
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.,Texas Children's Hospital, Houston, Texas, USA
| | - Sarah H Elsea
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.,Texas Children's Hospital, Houston, Texas, USA.,Joint BCM-CUHK Center of Medical Genetics, Prince of Wales Hospital, Shatin, Hong Kong SAR
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10
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Mitochondrial and Peroxisomal Alterations Contribute to Energy Dysmetabolism in Riboflavin Transporter Deficiency. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:6821247. [PMID: 32855765 PMCID: PMC7443020 DOI: 10.1155/2020/6821247] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/07/2020] [Accepted: 07/13/2020] [Indexed: 12/16/2022]
Abstract
Riboflavin transporter deficiency (RTD) is a childhood-onset neurodegenerative disorder characterized by progressive pontobulbar palsy, sensory and motor neuron degeneration, sensorineural hearing loss, and optic atrophy. As riboflavin (RF) is the precursor of FAD and FMN, we hypothesize that both mitochondrial and peroxisomal energy metabolism pathways involving flavoproteins could be directly affected in RTD, thus impacting cellular redox status. In the present work, we used induced pluripotent stem cells (iPSCs) from RTD patients to investigate morphofunctional features, focusing on mitochondrial and peroxisomal compartments. Using this model, we document the following RTD-associated alterations: (i) abnormal colony-forming ability and loss of cell-cell contacts, revealed by light, electron, and confocal microscopy, using tight junction marker ZO-1; (ii) mitochondrial ultrastructural abnormalities, involving shape, number, and intracellular distribution of the organelles, as assessed by focused ion beam/scanning electron microscopy (FIB/SEM); (iii) redox imbalance, with high levels of superoxide anion, as assessed by MitoSOX assay accompanied by abnormal mitochondrial polarization state, evaluated by JC-1 staining; (iv) altered immunofluorescence expression of antioxidant systems, namely, glutathione, superoxide dismutase 1 and 2, and catalase, as assessed by quantitatively evaluated confocal microscopy; and (v) peroxisomal downregulation, as demonstrated by levels and distribution of fatty acyl β-oxidation enzymes. RF supplementation results in amelioration of cell phenotype and rescue of redox status, which was associated to improved ultrastructural features of mitochondria, thus strongly supporting patient treatment with RF, to restore mitochondrial- and peroxisomal-related aspects of energy dysmetabolism and oxidative stress in RTD syndrome.
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Tolomeo M, Nisco A, Leone P, Barile M. Development of Novel Experimental Models to Study Flavoproteome Alterations in Human Neuromuscular Diseases: The Effect of Rf Therapy. Int J Mol Sci 2020; 21:ijms21155310. [PMID: 32722651 PMCID: PMC7432027 DOI: 10.3390/ijms21155310] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 02/07/2023] Open
Abstract
Inborn errors of Riboflavin (Rf) transport and metabolism have been recently related to severe human neuromuscular disorders, as resulting in profound alteration of human flavoproteome and, therefore, of cellular bioenergetics. This explains why the interest in studying the “flavin world”, a topic which has not been intensively investigated before, has increased much over the last few years. This also prompts basic questions concerning how Rf transporters and FAD (flavin adenine dinucleotide) -forming enzymes work in humans, and how they can create a coordinated network ensuring the maintenance of intracellular flavoproteome. The concept of a coordinated cellular “flavin network”, introduced long ago studying humans suffering for Multiple Acyl-CoA Dehydrogenase Deficiency (MADD), has been, later on, addressed in model organisms and more recently in cell models. In the frame of the underlying relevance of a correct supply of Rf in humans and of a better understanding of the molecular rationale of Rf therapy in patients, this review wants to deal with theories and existing experimental models in the aim to potentiate possible therapeutic interventions in Rf-related neuromuscular diseases.
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