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The Journal of Nutritional Biochemistry Dec 2023Insufficient riboflavin intake has been associated with poor bone health. This study aimed to investigate the effect of riboflavin deficiency on bone health in vivo and...
Insufficient riboflavin intake has been associated with poor bone health. This study aimed to investigate the effect of riboflavin deficiency on bone health in vivo and in vitro. Riboflavin deficiency was successfully developed in rats and osteoblasts. The results indicated that bone mineral density, serum bone alkaline phosphatase, bone phosphorus, and bone calcium were significantly decreased while serum ionized calcium and osteocalcin were significantly increased in the riboflavin-deficient rats. Riboflavin deficiency also induced the reduction of Runx2, Osterix, and BMP-2/Smad1/5/9 cascade in the femur. These results were further verified in cellular experiments. Our findings demonstrated that alkaline phosphatase activities and calcified nodules were significantly decreased while intracellular osteocalcin and pro-collagen I c-terminal propeptide were significantly increased in the riboflavin-deficient osteoblasts. Additionally, the protein expression of Osterix, Runx2, and BMP-2/Smad1/5/9 cascade were significantly decreased while the protein expression of p-p38 MAPK were significantly increased in the riboflavin-deficient cells compared to the control cells. Blockage of p38 MAPK signaling pathway with SB203580 reversed these effects in riboflavin-deficient osteoblastic cells. Our data suggest that riboflavin deficiency causes osteoblast malfunction and retards bone matrix mineralization via p38 MAPK/BMP-2/Smad1/5/9 signaling pathway.
Topics: Rats; Animals; Bone Density; Core Binding Factor Alpha 1 Subunit; Osteocalcin; Signal Transduction; Riboflavin Deficiency; Alkaline Phosphatase; Calcium; Bone Morphogenetic Protein 2; Osteoblasts; p38 Mitogen-Activated Protein Kinases; Riboflavin; Cell Differentiation
PubMed: 37788723
DOI: 10.1016/j.jnutbio.2023.109453 -
European Journal of Pharmacology Sep 2023Short-chain acyl-CoA dehydrogenase (SCAD), the rate-limiting enzyme for fatty acid β-oxidation, has a negative regulatory effect on pathological cardiac hypertrophy and...
Short-chain acyl-CoA dehydrogenase (SCAD), the rate-limiting enzyme for fatty acid β-oxidation, has a negative regulatory effect on pathological cardiac hypertrophy and fibrosis. FAD, a coenzyme of SCAD, participates in the electron transfer of SCAD-catalyzed fatty acid β-oxidation, which plays a crucial role in maintaining the balance of myocardial energy metabolism. Insufficient riboflavin intake can lead to symptoms similar to short-chain acyl-CoA dehydrogenase (SCAD) deficiency or flavin adenine dinucleotide (FAD) gene abnormality, which can be alleviated by riboflavin supplementation. However, whether riboflavin can inhibit pathological cardiac hypertrophy and fibrosis remains unclear. Therefore, we observed the effect of riboflavin on pathological cardiac hypertrophy and fibrosis. In vitro experiments, riboflavin increased SCAD expression and the content of ATP, decreased the free fatty acids content and improved PE-induced cardiomyocytes hypertrophy and AngⅡ-induced cardiac fibroblasts proliferation by increasing the content of FAD, which were attenuated by knocking down the expression of SCAD using small interfering RNA. In vivo experiments, riboflavin significantly increased the expression of SCAD and the energy metabolism of the heart to improve TAC induced pathological myocardial hypertrophy and fibrosis in mice. The results demonstrate that riboflavin improves pathological cardiac hypertrophy and fibrosis by increasing the content of FAD to activate SCAD, which may be a new strategy for treating pathological cardiac hypertrophy and fibrosis.
Topics: Animals; Mice; Butyryl-CoA Dehydrogenase; Flavin-Adenine Dinucleotide; Riboflavin; Cardiomegaly; Fatty Acids, Nonesterified; Fibrosis
PubMed: 37331684
DOI: 10.1016/j.ejphar.2023.175849 -
Neuromolecular Medicine Dec 2023AIFM1 is a mitochondrial flavoprotein involved in caspase-independent cell death and regulation of respiratory chain complex biogenesis. Mutations in the AIFM1 gene have...
AIFM1 is a mitochondrial flavoprotein involved in caspase-independent cell death and regulation of respiratory chain complex biogenesis. Mutations in the AIFM1 gene have been associated with multiple clinical phenotypes, but the effectiveness of riboflavin treatment remains controversial. Furthermore, few studies explored the reasons underlying this controversy. We reported a 7-year-old boy with ataxia, sensorimotor neuropathy and muscle weakness. Genetic and histopathological analyses were conducted, along with assessments of mitochondrial function and apoptosis level induced by staurosporine. Riboflavin deficiency and supplementation experiments were performed using fibroblasts. A missense c.1019T > C (p. Met340Thr) variant of AIFM1 was detected in the proband, which caused reduced expression of AIFM1 protein and mitochondrial dysfunction as evidenced by downregulation of mitochondrial complex subunits, respiratory deficiency and collapse of ΔΨm. The proportion of apoptotic cells in mutant fibroblasts was lower than controls after induction of apoptosis. Riboflavin deficiency resulted in decreased AIFM1 protein levels, while supplementation with high concentrations of riboflavin partially increased AIFM1 protein levels in variant fibroblasts. In addition, mitochondrial respiratory function of mutant fibroblasts was partly improved after riboflavin supplementation. Our study elucidated the pathogenicity of the AIFM1 c.1019T > C variant and revealed mutant fibroblasts was intolerant to riboflavin deficiency. Riboflavin supplementation is helpful in maintaining the level of AIFM1 protein and mitochondrial respiratory function. Early riboflavin treatment may serve as a valuable attempt for patients with AIFM1 variant.
Topics: Male; Humans; Child; Riboflavin Deficiency; Riboflavin; Mutation, Missense; Mitochondria; Mitochondrial Diseases; Apoptosis Inducing Factor
PubMed: 37603145
DOI: 10.1007/s12017-023-08750-5 -
Pediatric Neurology Jul 2023Riboflavin transporter deficiency is a rare but severe neurometabolic disorder.
BACKGROUND
Riboflavin transporter deficiency is a rare but severe neurometabolic disorder.
METHODS
We report two siblings with pathogenic variants in SLC52A3 gene, resulting in riboflavin transporter 3 deficiency.
RESULTS
The first sibling was diagnosed at age 11 months with severe respiratory compromise and regression of developmental milestones. His symptoms significantly improved with riboflavin supplementation therapy. The younger sibling was diagnosed by antenatal genetic analysis; riboflavin supplementation was initiated in utero and continued from birth. Now at age two years, he remains clinically asymptomatic despite genetic confirmation of riboflavin transporter deficiency.
CONCLUSIONS
Antenatal riboflavin supplementation is a safe and effective treatment for the prevention of symptomatic manifestations of riboflavin transporter deficiency.
Topics: Pregnancy; Male; Humans; Female; Infant; Child, Preschool; Riboflavin; Bulbar Palsy, Progressive; Vitamins; Membrane Transport Proteins; Hearing Loss, Sensorineural
PubMed: 37116404
DOI: 10.1016/j.pediatrneurol.2023.04.004 -
Journal of the Neurological Sciences Dec 2023
PubMed: 38040566
DOI: 10.1016/j.jns.2023.122809 -
Journal of the Neurological Sciences Jan 2024There are scarce reports of riboflavin-responsive lipid storage myopathy in elderly patients with onset in their sixties. We describe three elderly patients with...
There are scarce reports of riboflavin-responsive lipid storage myopathy in elderly patients with onset in their sixties. We describe three elderly patients with riboflavin-responsive lipid-storage myopathy. All three patients (aged 67-71 years on first examination) had subacute onset of neck extensors and proximal limb weakness progressing to inability to rise from a sitting position or to walk. Muscle biopsies showed vacuoles with lipid content, mainly in type 1 fibers. Genetic analysis failed to identify any pathogenic variant in one patient, identified a heterozygous variant of uncertain significance c.812 A > G; p.Tyr271Cys in the ETFDH gene in the second patient, and revealed a heterozygote likely pathogenic variant c.1286-2 A > C in the ETFDH gene predicted to cause abnormal splicing in the third patient. All patients responded to treatment with riboflavin and carnitine, and regained normal strength. This report emphasizes the importance of muscle biopsy in revealing treatable lipid storage myopathy in elderly patients with progressive myopathy of unidentifiable cause.
Topics: Humans; Aged; Muscle, Skeletal; Multiple Acyl Coenzyme A Dehydrogenase Deficiency; Electron-Transferring Flavoproteins; Iron-Sulfur Proteins; Oxidoreductases Acting on CH-NH Group Donors; Muscular Diseases; Riboflavin; Lipids; Lipid Metabolism, Inborn Errors; Muscular Dystrophies
PubMed: 38043332
DOI: 10.1016/j.jns.2023.122808 -
Journal of the Peripheral Nervous... Jun 2024Riboflavin transporter deficiency (RTD) is a progressive inherited neuropathy of childhood onset, characterised clinically by pontobulbar palsy, sensory ataxia,...
BACKGROUND AND AIMS
Riboflavin transporter deficiency (RTD) is a progressive inherited neuropathy of childhood onset, characterised clinically by pontobulbar palsy, sensory ataxia, sensorineural deafness, muscle weakness, optic atrophy and respiratory failure. A robust and responsive functional outcome measure is essential for future clinical trials of disease-modifying therapies including genetic therapies. The Charcot-Marie-Tooth disease Pediatric Scale (CMTPedS) is a well-validated outcome measure for CMT and related neuropathies, and might have utility for measuring disease progression in individuals with RTD. However, the CMTPedS requires modifications to account for phenotypic differences between children with CMT and RTD. The aim of this study was to develop a functional outcome measure based on the CMTPedS for specific use in individuals with RTD.
METHODS
The CMTPedS data collected over the last 10 years in individuals with RTD attending the Peripheral Neuropathy Management Clinic at the Children's Hospital at Westmead (Sydney, Australia) were reviewed to evaluate each item within the CMTPedS. A literature review of articles published until September 2021 for functional outcome measures generated an item pool for pilot testing. The results of this pilot testing, alongside analysis of existing CMTPedS item scores in the RTD cohort, informed the modification of the CMTPedS.
RESULTS
CMTPedS data were reviewed for eight individuals over the past 10 years. Two items were identified as requiring modification or removal and additional items of proximal strength and function needed to be considered. Six studies were identified in the literature review, and five items were selected for pilot testing. 'Shoulder internal rotation' and the '30-s sit to stand test' were added as proximal measures of strength and function. The composite balance item comprising nine tasks in the CMTPedS showed a ceiling effect and was replaced with the single 'Feet apart on a line eyes open' balance item. 'Pinprick sensation' was removed due to a floor effect.
INTERPRETATION
This study provides preliminary evidence that the Riboflavin Transporter Deficiency Pediatric Scale (RTDPedS) is a functional outcome measure covering strength, upper and lower limb function, balance and mobility for individuals with RTD to assess disease severity and progression in clinical trials and cohort studies.
Topics: Humans; Child; Hearing Loss, Sensorineural; Bulbar Palsy, Progressive; Male; Outcome Assessment, Health Care; Female; Adolescent; Child, Preschool; Charcot-Marie-Tooth Disease; Membrane Transport Proteins
PubMed: 38445790
DOI: 10.1111/jns.12619 -
Cell Death Discovery Jan 2024Riboflavin Transporter Deficiency (RTD) is a rare genetic, childhood-onset disease. This pathology has a relevant neurological involvement, being characterized by motor...
Riboflavin Transporter Deficiency (RTD) is a rare genetic, childhood-onset disease. This pathology has a relevant neurological involvement, being characterized by motor symptoms, ponto-bulbar paralysis and sensorineural deafness. Such clinical presentation is associated with muscle weakness and motor neuron (MN) degeneration, so that RTD is considered part of the MN disease spectrum. Based on previous findings demonstrating energy dysmetabolism and mitochondrial impairment in RTD induced Pluripotent Stem cells (iPSCs) and iPSC-derived MNs, here we address the involvement of intrinsic apoptotic pathways in disease pathogenesis using these patient-specific in vitro models by combined ultrastructural and confocal analyses. We show impaired neuronal survival of RTD iPSCs and MNs. Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM) documents severe alterations in patients' cells, including deranged mitochondrial ultrastructure, and altered plasma membrane and nuclear organization. Occurrence of aberrantly activated apoptosis is confirmed by immunofluorescence and TUNEL assays. Overall, our work provides evidence of a role played by mitochondrial dysfunction in RTD, and identifies neuronal apoptosis as a contributing event in disease pathogenesis, indicating intrinsic apoptosis pathways as possible relevant targets for more effective therapeutical approaches.
PubMed: 38278809
DOI: 10.1038/s41420-024-01812-y -
Nutrition & Metabolism Jan 2024Non-alcoholic fatty liver disease (NAFLD) is characterized by excessive lipid accumulation in the liver. Riboflavin, one of water soluble vitamins, plays a role in lipid...
BACKGROUND
Non-alcoholic fatty liver disease (NAFLD) is characterized by excessive lipid accumulation in the liver. Riboflavin, one of water soluble vitamins, plays a role in lipid metabolism and antioxidant function. However, the effects of riboflavin deficiency on NAFLD development have not yet to be fully explored.
METHODS
In the present study, an animal model of NAFLD was induced by high fat diet feeding in mice and a cellular model of NAFLD was developed in HepG2 cells by palmitic acid (PA) exposure. The effects of riboflavin deficiency on lipid metabolism and antioxidant function were investigated both in vivo and in vitro. In addition, the possible role of peroxisome proliferator-activated receptor gamma (PPARγ) was studied in HepG2 cells using gene silencing technique.
RESULTS
The results showed that riboflavin deficiency led to hepatic lipid accumulation in mice fed high fat diet. The expressions of fatty acid synthase (FAS) and carnitine palmitoyltransferase 1 (CPT1) were up-regulated, whereas that of adipose triglyceride lipase (ATGL) down-regulated. Similar changes in response to riboflavin deficiency were demonstrated in HepG2 cells treated with PA. Factorial analysis revealed a significant interaction between riboflavin deficiency and high dietary fat or PA load in the development of NAFLD. Hepatic PPARγ expression was significantly upregulated in mice fed riboflavin deficient and high fat diet or in HepG2 cells treated with riboflavin deficiency and PA load. Knockdown of PPARγ gene resulted in a significant reduction of lipid accumulation in HepG2 cells exposed to riboflavin deficiency and PA load.
CONCLUSIONS
There is a synergetic action between riboflavin deficiency and high dietary fat on the development of NAFLD, in which PPARγ may play an important role.
PubMed: 38169398
DOI: 10.1186/s12986-023-00775-8