Novel aberrant genetic and epigenetic events in Friedreich's ataxia.
It is generally accepted that Friedreich's ataxia (FRDA) is caused by a deficiency in frataxin expression, a mitochondrial protein involved in iron homeostasis, which mainly affects the brain, dorsal root ganglia of the spinal cord, heart and in certain cases the pancreas. However, there is little knowledge as to other possible genes that may be affected in this disorder, and which can contribute to its complexity. In the current study we compared human periodontal ligament cells gene expression of healthy individuals and FRDA patients. The expression of active-caspase 3, as well as other apoptosis-related genes, was increased in the FRDA cells. Furthermore, iron-sulphur cluster genes, as well as oxidative stress-related genes were overexpressed in FRDA. Moreover, brain-derived neurotrophic factor, neuregulin 1 and miR-132 were all upregulated. These three genes are capable of regulating the expression of each other. Interestingly, when the cells from FRDA patients were co-cultured in the presence of idebenone and deferiprone, caspase expression decreased while antioxidant gene expression, as well as frataxin expression, increased. Regarding epigenetic mechanisms, the frataxin gene was hypermethylated, compared to the healthy counterparts, in the upstream GAA repetitive region. Of the three DNA methyltransferases, DNMT1 but not DNMT3׳s gene expression was higher in FRDA cells. In conclusion, our data show that FRDA cells present altered expression of genes related to cell cycle, oxidative stress and iron homeostasis which may be implicated in the increased apoptotic levels. Also, the altered expression is in a certain degree normalized in the presence of idebenone and deferiprone.
Neuroscience Institute, Miguel Hernandez University (UMH-CSIC), San Juan, Alicante, Spain; IMIB-Arrixaca and Centro de Investigación Biomédica en Red en el Área de Salud Mental (CIBERSAM), University of Murcia, Murcia, Spain.
Mari Paz
MP
Quesada
Neuroscience Institute, Miguel Hernandez University (UMH-CSIC), San Juan, Alicante, Spain.
Jonathan
J
Jones
School of Dentistry, Faculty of Medicine, University of Murcia, Murcia, Spain.
F J
FJ
Rodríguez-Lozano
Hematology Department, Hematopoietic Transplant and Cellular Therapy Unit, Virgen de la Arrixaca Clinical University Hospital, IMIB-Arrixaca, University of Murcia, Spain.
Jose M
JM
Moraleda
Neuroscience Institute, Miguel Hernandez University (UMH-CSIC), San Juan, Alicante, Spain; IMIB-Arrixaca and Centro de Investigación Biomédica en Red en el Área de Salud Mental (CIBERSAM), University of Murcia, Murcia, Spain. Electronic address: salvador@um.es.
Salvador
S
Martinez
D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000235:genetics; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D019208:Brain-Derived Neurotrophic Factor / Q000096:biosynthesis; D053148:Caspase 3 / Q000096:biosynthesis*; D002478:Cells, Cultured; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000096:biosynthesis; D019175:DNA Methylation; D000077209:Decitabine; D000077543:Deferiprone; D044127:Epigenesis, Genetic; D005621:Friedreich Ataxia / Q000235:genetics*; D020869:Gene Expression Profiling; D006801:Humans; D007502:Iron Chelating Agents / Q000494:pharmacology; D033862:Iron-Binding Proteins / Q000096:biosynthesis*; D035683:MicroRNAs / Q000096:biosynthesis*; D020890:Neuregulin-1 / Q000096:biosynthesis; D018384:Oxidative Stress / Q000235:genetics*; D010513:Periodontal Ligament / Q000166:cytology; D011728:Pyridones / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000235:genetics; D014451:Ubiquinone / Q000031:analogs & derivatives / Q000494:pharmacology; D000096923:Frataxin
D000975:Antioxidants; D001374:Azacitidine; D019208:Brain-Derived Neurotrophic Factor; D053148:Caspase 3; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; D000077209:Decitabine; D000077543:Deferiprone; D007502:Iron Chelating Agents; D033862:Iron-Binding Proteins; D035683:MicroRNAs; D020890:Neuregulin-1; D011728:Pyridones; D013482:Superoxide Dismutase; D014451:Ubiquinone; D000096923:Frataxin; C547077:MIRN132 microRNA, human; C559060:MIRN886 microRNA, human; C094131:NRG1 protein, human; C579455:BDNF protein, human; C000619380:DNMT1 protein, human; C036619:idebenone
Apoptosis; DNA methylation; Frataxin; Friedreich׳s ataxia; Periodontal ligament cells; miRNAs