6 results on '"Frataxin (FXN)"'
Search Results
2. A Drug Combination Rescues Frataxin-Dependent Neural and Cardiac Pathophysiology in FA Models
- Author
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Rosella Abeti, Mittal Jasoliya, Sahar Al-Mahdawi, Mark Pook, Cristina Gonzalez-Robles, Chun Kiu Hui, Gino Cortopassi, and Paola Giunti
- Subjects
Friedreich’s Ataxia (FA) ,Frataxin (FXN) ,Dimethyl fumarate (DMF) ,Resveratrol (Resv) ,Mitochondrial membrane potential (ΔΨm) ,Reactive Oxygen species (ROS) ,Biology (General) ,QH301-705.5 - Abstract
Friedreich’s ataxia (FA) is an inherited multisystemic neuro- and cardio-degenerative disorder. Seventy-four clinical trials are listed for FA (including past and present), but none are considered FDA/EMA-approved therapy. To date, FA therapeutic strategies have focused along two main lines using a single-drug approach: a) increasing frataxin and b) enhancing downstream pathways, including antioxidant levels and mitochondrial function. Our novel strategy employed a combinatorial approach to screen approved compounds to determine if a combination of molecules provided an additive or synergistic benefit to FA cells and/or animal models. Eight single drug molecules were administered to FA fibroblast patient cells: nicotinamide riboside, hemin, betamethasone, resveratrol, epicatechin, histone deacetylase inhibitor 109, methylene blue, and dimethyl fumarate. We measured their individual ability to induce FXN transcription and mitochondrial biogenesis in patient cells. Single-drug testing highlighted that dimethyl fumarate and resveratrol increased these two parameters. In addition, the simultaneous administration of these two drugs was the most effective in terms of FXN mRNA and mitobiogenesis increase. Interestingly, this combination also improved mitochondrial functions and reduced reactive oxygen species in neurons and cardiomyocytes. Behavioral tests in an FA mouse model treated with dimethyl fumarate and resveratrol demonstrated improved rotarod performance. Our data suggest that dimethyl fumarate is effective as a single agent, and the addition of resveratrol provides further benefit in some assays without showing toxicity. Therefore, they could be a valuable combination to counteract FA pathophysiology. Further studies will help fully understand the potential of a combined therapeutic strategy in FA pathophysiology.
- Published
- 2022
- Full Text
- View/download PDF
3. A Comprehensive Transcriptome Analysis Identifies FXN and BDNF as Novel Targets of miRNAs in Friedreich's Ataxia Patients.
- Author
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Misiorek, Julia O., Schreiber, Anna M., Urbanek-Trzeciak, Martyna O., Jazurek-Ciesiołka, Magdalena, Hauser, Lauren A., Lynch, David R., Napierala, Jill S., and Napierala, Marek
- Abstract
Friedreich's ataxia (FRDA) is a genetic neurodegenerative disease that is caused by guanine-adenine-adenine (GAA) nucleotide repeat expansions in the first intron of the frataxin (FXN) gene. Although present in the intron, this mutation leads to a substantial decrease in protein expression. Currently, no effective treatment is available for FRDA, and, in addition to FXN, other targets with therapeutic potential are continuously sought. As miRNAs can regulate the expression of a broad spectrum of genes, are used as biomarkers, and can serve as therapeutic tools, we decided to identify and characterize differentially expressed miRNAs and their targets in FRDA cells compared to unaffected control (CTRL) cells. In this study, we performed an integrated miRNAseq and RNAseq analysis using the same cohort of primary FRDA and CTRL cells. The results of the transcriptome studies were supported by bioinformatic analyses and validated by qRT-PCR. miRNA interactions with target genes were assessed by luciferase assays, qRT-PCR, and immunoblotting. In silico analysis identified the FXN transcript as a target of five miRNAs upregulated in FRDA cells. Further studies confirmed that miRNA-224-5p indeed targets FXN, resulting in decreases in mRNA and protein levels. We also validated the ability of miRNA-10a-5p to bind and regulate the levels of brain-derived neurotrophic factor (BDNF), an important modulator of neuronal growth. We observed a significant decrease in the levels of miRNA-10a-5p and increase in the levels of BDNF upon correction of FRDA cells via zinc-finger nuclease (ZFN)-mediated excision of expanded GAA repeats. Our comprehensive transcriptome analyses identified miRNA-224-5p and miRNA-10a-5p as negative regulators of the FXN and BDNF expression, respectively. These results emphasize not only the importance of miRNAs in the pathogenesis of FRDA but also their potential as therapeutic targets for this disease. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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- View/download PDF
4. Μελέτη της έκφρασης του γονιδίου της φραταξίνης (FXN) στην καρδιακή διαφοροποίηση επαγόμενων πολυδύναμων βλαστικών κυττάρων ανθρώπου
- Subjects
Επαγόμενα βλαστοκύτταρα ,Φραταξίνη ,Induced pluripotent stem cells (IPSCs) ,Frataxin (FXN) ,Καρδιομυοκύτταρα ,Cardiomyocytes (CM) - Abstract
Η αταξία Friedreich είναι μία από τις συχνότερες νωτιοπαρεγκεφαλιδικές αταξίες. Η νόσος προκαλείται από μια μεγάλη αύξηση τρινουκλεοτιδικών επαναλήψεων GAA του γονιδίου της φραταξίνης (FXN) στον μεγάλο βραχίονα του χρωμοσώματος 9. Οι ασθενείς εμφανίζουν εκφύλιση στις οπίσθιες δέσμες, στα πυραμιδικά δεμάτια και στα νωτιοπαρεγκεφαλιδικά δεμάτια του νωτιαίου μυελού. Η κλινική εικόνα της νόσου ξεκινάει κατά την παιδική ηλικία με αταξία κυρίως στην βάδιση, μειωμένα τενόντια αντανακλαστικά, ατροφία και αδυναμία στα περιφερικά τμήματα των άκρων. Υπερτροφική καρδιομυοπάθεια, σκολίωση και κοιλοποδία εμφανίζονται στο 90% των περιπτώσεων και οι ασθενείς καταλήγουν συνήθως έπειτα από καρδιοπνευμονικές επιπλοκές. Μέχρι σήμερα δεν υπάρχει οριστική θεραπεία της νόσου η οποία αφορά την αντιμετώπιση των συμπτωμάτων και έχει παρηγορητικό χαρακτήρα. Ωστόσο νέες μέθοδοι που στοχεύουν στην γενετική τροποποίηση του γονιδίου της φραταξίνης βρίσκονται σε εξέλιξη με ενθαρρυντικά αποτελέσματα. Τα επαγόμενα πολυδύναμα βλαστοκύτταρα (iPSCs) χρησιμοποιούνται ευρέως στην έρευνα για την καταπολέμηση της FRDA, καθώς επιτρέπουν την πρόσβαση σε άμεσα επηρεαζόμενους ιστούς της νόσου, οι οποίοι έχουν δύσκολη πρόσβαση (νευρικά κύτταρα, καρδιομυοκύτταρα και παγκρεατικά κύτταρα). Μέσω της διέγερσης και της καταστολής του μονοπατιού Wnt σε διάφορα στάδια της διαφοροποίησης καθώς και της χρήσης κατάλληλου θρεπτικού μέσου μπορούμε να καθοδηγήσουμε τα βλαστικά κύτταρα σε καρδιακό μεσόδερμα και τελικά στον σχηματισμό καρδιομυοκυττάρων με συσταλτική δραστηριότητα. Στην παρούσα διπλωματική εργασία μέσω της χρήσης τεχνικών γονιδιακής τροποποίησης με την βοήθεια του συστήματος CRISPR/CAS9 κατασκευάστηκαν κυτταρικές τράπεζες καρδιομυοκυττάρων με υπερέκφραση και υποέκφραση του γονιδίου της φραταξίνης για την μελέτη της ασθένειας in vitro και μελετήθηκε το πρότυπο έκφρασης του γονιδίου της φραταξίνης στα διάφορα στάδια της καρδιακής διαφοροποίησης επαγόμενων πολυδύναμων βλαστοκυττάρων ανθρώπου. Τα αποτελέσματα των πειραμάτων πιστοποίησαν την επιτυχής ένθεση των αλληλουχιών αποσιώπησης και υπερέκφρασης του γονιδίου της φραταξίνης σε επαγόμενα ανθρώπινα βλαστοκύτταρα. Επίσης, η ανοσοαποτύπωση κατά Western ανέδειξε διαφορές στην πρωτεϊνική έκφραση της φραταξίνης στα διάφορα στάδια διαφοροποίησης των επαγόμενων βλαστοκυττάρων προς καρδιομυοκύτταρα. Η έκφραση της φραταξίνης εμφάνισε μια αύξηση την ημέρα 7 της διαφοροποίησης όπου τα κύτταρα είναι πλέον καρδιακοί προγεννήτορες και παρέμεινε αυξημένη την ημέρα 10 της διαφοροποίησης όπου τα κύτταρα είχαν διαφοροποιηθεί πλήρως σε καρδιακά κύτταρα με περισταλτισμό, γεγονός που καταδεικνύει την σημασία της φραταξίνης στην ανάπτυξη της καρδιάς., Friedreich's ataxia is one of the most common spinocerebellar disorders. The disease is caused by multiple GAA trinucleotide repeats of the frataxin gene (FXN) located on the long arm of chromosome 9. Patients show degeneration of the posterior bundles, pyramidal bundles, and spinocerebellar bundles of the spinal cord. The clinical signs of the disease begin during childhood including ataxia mainly in walking, reduced tendon reflexes, atrophy and weakness in the peripheral parts of the limbs. Hypertrophic cardiomyopathy, scoliosis, and clubfoot occur in 90% of cases, and patients die mainly because of cardiopulmonary complications. To date, there is no treatment for the disease. However, new methods such as gene editing of frataxin gene are underway with encouraging results. Induced pluripotent stem cells (iPSCs) are widely used in FRDA research, as they allow access to directly affected tissues of the disease, such as neural cells, cardiomyocytes, and pancreatic cells. The stimulation and suppression of the Wnt pathway at specific developmental stages as well as the use of a suitable medium, guides the differentiation of stem cells into cardiac mesoderm and ultimately to the formation of cardiomyocytes with contractile activity. In this thesis, we tested the use of CRISPR/Cas9 using gene editing techniques with the help of CRISPR/CAS9 system, cardiomyocyte cell banks with knock in and knock out of the frataxin gene were constructed. Also, we studied the expression pattern of the frataxin gene at various stages of cardiac differentiation. The results of the experiments showed successful creation of iPSCs-induced cardiomyocytes with silencing and overexpression sequences of the frataxin gene. Also, Western immunoblotting revealed differences in the protein expression of frataxin at different stages of cardiac differentiation. Frataxin expression showed an increase at day 7 of differentiation where the cells were cardiac progenitors and remained elevated at day 10 of differentiation where the cells had fully differentiated into cardiomyocyte, highlighting the importance of frataxin in heart development.
- Published
- 2023
- Full Text
- View/download PDF
5. Imatinib inhibits the expression of SCO2 and FRATAXIN genes that encode mitochondrial proteins in human Bcr–Abl+ leukemia cells.
- Author
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Papadopoulou, Lefkothea C., Kyriazou, Angeliki V., Bonovolias, Ioannis D., and Tsiftsoglou, Asterios S.
- Subjects
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DRUG therapy , *IMATINIB , *LEUKEMIA , *MITOCHONDRIAL proteins , *PROTEIN-tyrosine kinase inhibitors , *CYTOCHROME oxidase , *GENE expression - Abstract
Imatinib mesylate (IM/Gleevec®), a selective inhibitor of chimeric Bcr–Abl tyrosine kinase, was developed as a first line drug to treat CML and ALL Ph+ patients. Earlier studies have shown that hemin counteracts the IM-induced cell killing in human K-562 CML cells. In this study, we investigated whether IM disrupts the heme-dependent Cytochrome c Oxidase (COX) Biosynthesis and Assembly Pathway (HDCBAP) in Bcr–Abl+ and Bcr–Abl− cells by affecting the expression of key-genes. Cells were exposed to IM and evaluated at time intervals for cell growth, cell death, expression of various genes by RT-PCR analysis as well as Sco2 mature protein levels by western blot analysis and COX enzymatic activity. IM at 1μM induced extensive cell growth inhibition and cell death as well as marked suppression of the expression of SCO2 and FRATAXIN (FXN) genes in human K-562 and KU-812 Bcr–Abl+ CML cells. IM also reduced the protein level of mature Sco2 mitochondrial protein as well as COX activity in these cell lines. However, treatment of human MOLT-4 Bcr–Abl− cells with 1μM and even with higher concentrations (4×10−5 M) of IM neither reduced the expression of SCO2 and FXN genes nor suppressed the protein level of mature Sco2 protein and COX activity. Our findings indicate that SCO2 and FXN genes, involved in HDCBAP, are repressed by IM in human Bcr–Abl+ CML cells and may represent novel target sites in leukemia therapy. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
6. Large interruptions of GAA repeat expansiopns mutations in Friedreich ataxia are very rare
- Author
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Pook, M, Al-Mahdawi, S, Ging, H, Bayot, A, Cavalcanti, F, La Cognata, V, Cavallaro, S, and Giunti, P
- Subjects
congenital, hereditary, and neonatal diseases and abnormalities ,nutritional and metabolic diseases ,Friedreich Ataxia (FRDA) ,Frataxin (FXN) ,GAA repeat expansion ,Cerebella ataxia ,Neurodegenarative disease - Abstract
Copyright © 2018 Al-Mahdawi, Ging, Bayot, Cavalcanti, La Cognata, Cavallaro, Giunti and Pook. Friedreich ataxia is a multi-system autosomal recessive inherited disorder primarily caused by homozygous GAA repeat expansion mutations within intron 1 of the frataxin gene. The resulting deficiency of frataxin protein leads to progressive mitochondrial dysfunction, oxidative stress and cell death, with the main affected sites being the large sensory neurons of the dorsal root ganglia and the dentate nucleus of the cerebellum. The GAA repeat expansions may be pure (GAA)n in sequence or may be interrupted with regions of non-GAA sequence. To our knowledge there has been no large-scale study of FRDA patient DNA samples to determine the frequency of large interruptions in GAA repeat expansions. Therefore, we have investigated a panel of 245 Friedreich ataxia patient and carrier DNA samples using GAA repeat PCR amplification and MboII restriction enzyme digestion. We demonstrate that the vast majority (97.8%) of Friedreich ataxia GAA repeat expansion samples do not contain significant sequence changes that would result in abnormal MboII digestion profiles, indicating that they are primarily pure GAA repeats. These results show for the first time that large interruptions in the GAA repeats are very rare. European Union Seventh Framework Programme
- Published
- 2018
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