Discovering genetic causes of optic atrophy syndromes through whole exome sequencing
Ontology highlight
ABSTRACT:
PROVIDER: EGAS00001003850 | EGA |
REPOSITORIES: EGA
Similar Datasets
Project description:LHON is a paraLeber hereditary optic neuropathy (LHON) is a paradigm for mitochondrial retinopathy due to mitochondrial DNA (mtDNA) mutations. However, the mechanism underlying retinal cell-specific effects of LHON-linked mtDNA mutations remains poorly understood and there has been no effective treatment or cure for this disorder. We use scRNA-seq to study the retinal cell-specific deficiencies caused by LHON-linked ND6P25L mutation.
2025-04-22 | GSE280785 | GEO
Project description:SSBP1 mutations cause a complex optic atrophy spectrum disorder with mitochondrial DNA depletion
| EGAS00001004003 | EGA
Project description:This study aims to confirm the pathogenic role of the AFG3L2 F175S mutation in dominant optic atrophy (DOA) and elucidate its molecular mechanisms disrupting mitochondrial morphology and function.
2025-06-03 | PXD064587 |
Project description:The cornea is the transparent tissue covering the anterior part of the eye. Its main roles are to convey the light toward the retina, and to act as a protective barrier against infection or injury for the eye. The transparency of the cornea is a crucial component of its functionality and is the result of specific architecture and cell arrangements. The inner layer of the cornea is the endothelium, composed of a monolayer of endothelial cells. The next layer is the stroma, representing about two third of the thickness of the cornea, and is mainly composed of a specifically arranged extracellular matrix, secreted by few keratocytes1–4. Finally, the external layer is a life-long renewed pluristratified epithelium. The regulated epithelial homeostasis, crucial to maintain the corneal transparency, relies on stem and progenitor cells5. To coordinate epithelial homeostasis and healing, and to adequately respond to any change in the corneal environment, this tissue is highly innervated6,7. The corneal innervation is mainly composed of A and C sensory fibres whose cell bodies are located in the ophthalmic branch of the trigeminal ganglion8. Those fibres penetrate the corneal stroma from the periphery, as bundles of fibres branching and spreading within the stroma9. When entering in the epithelium, the fibres branche again and radiate horizontally to form the subbasal plexus. Finally, the sensory fibres shift orientation to reach the top of the epithelium, where they end up as free nerve endings6,7. There are three classes of fibres innervating the cornea: the mechano-nociceptors, the cold sensing neurons and the polymodal nociceptors, reacting respectively to mechanical, thermal and chemical stimuli10,11. Stimuli transduction is not the only role of the corneal innervation, as these fibres have a crucial role on epithelial homeostasis through the secretion of trophic factors essential for epithelial cell survival12. Due to its localization, the cornea is highly exposed to ultraviolet radiation and high oxygen tension, making it particularly vulnerable to mitochondrial defects13. These defects can be either inherited or non-inherited. Inherited forms result from mutations in mitochondrial DNA (mtDNA) or nuclear gene defects affecting mitochondrial function14. Inherited mitochondrial dysfunction is a key factor in the progression of Fuchs endothelial corneal dystrophy (FECD) and keratoconus13,15,16. Non-inherited mitochondrial dysfunction, on the other hand, can occur due to spontaneous mtDNA mutations or somatic mutations that accumulate with age, rendering the mitochondrial metabolism less efficient with time17. To date, the impact of inherited mitochondrial dysfunctions on corneal epithelium physiology has not been extensively studied. Case reports have linked mitochondrial diseases to corneal cloudiness18,19, perforation20 and edema21. Furthermore, mitochondrial defect was associated to inflammatory context and ROS production in ocular surface pathologies13,22. Despite these studies, the direct effect of mitochondrial disfunction on corneal biology remains elusive. Among the known pathologies originating from an inherited mitochondrial dysfunction, the dominant optic atrophy (DOA) is an inherited blinding disease caused by the degenescence of the retinal cell ganglions forming the optic nerve23. The mutation of the gene OPA1 is responsible for the majority of the DOA diagnostics. OPA1 gene encodes for a mitochondrial protein involved in the fusion process and is essential to maintain the organelle integrity. Generally, optic neuropathy is the characteristic syndrome for DOA, but a subset of patients, called dominant optic atrophy plus (DOA+), also declare extra-ocular syndromes such as ataxia, deafness and peripheral neuropathies24,25. A mouse model, bearing the OPA1delTTAG mutation, recapitulates the degenerative syndromes encountered in DOA+ patients25.. While DOA is associated with lens cloudiness, no report has linked DOA to ocular surface defects. Here, we investigated the impact of OPA1 delTTAG mutation on mouse cornea as its structure includes a large amout of sensory fibres that are crucial to maintain corneal homeostasis.
2024-07-25 | PXD052337 | Pride
Project description:Somatic mitochondrial DNA (mtDNA) mutations contribute to the pathogenesis of age-related disorders, including myelodysplastic syndromes (MDS). The accumulation of mitochondria harboring mtDNA mutations in patients with these disorders suggests a failure of normal mitochondrial quality-control systems. The mtDNA-mutator mice acquire somatic mtDNA mutations via a targeted defect in the proofreading function of the mtDNA polymerase, PolgA, and develop macrocyticanemia similar to that of patients with MDS. We observed an unexpected defect in clearance of dysfunctional mitochondria at specific stages during erythroid maturation in hematopoietic cells from aged mtDNA-mutator mice. Mechanistically, aberrant activation of mechanistic target of rapamycin signaling and phosphorylation of uncoordinated 51-like kinase (ULK) 1 in mtDNA-mutator mice resulted in proteasome mediated degradation of ULK1 and inhibition of autophagy in erythroid cells. To directly evaluate the consequence of inhibiting autophagy on mitochondrial function in erythroid cells harboring mtDNA mutations in vivo, we deleted Atg7 from erythroid progenitors of wildtype and mtDNA-mutator mice. Genetic disruption of autophagy did not cause anemia in wild-type mice but accelerated the decline in mitochondrial respiration and development of macrocytic anemia in mtDNA-mutator mice. These findings highlight a pathological feedback loop that explains how dysfunctional mitochondria can escape autophagy-mediated degradation and propagate in cells predisposed to somatic mtDNA mutations, leading to disease. We used microarrays to identify expression profiles and pathways that are differentially activated or suppressed in Ter119+ bone marrow cells isolated from phlebotomized wildtype or Polg mutant mice
2015-04-21 | E-GEOD-57761 | biostudies-arrayexpress
Project description:Short read whole genome sequencing (WGS) CRAM files for the NIHR BioResource Rare Diseases WGS project – Participants from the Leber Hereditary Optic Neuropathy (LHON) Rare Disease domain
| EGAD00001005122 | EGA
Project description:MEPAN (Mitochondrial Enoyl CoA Reductase Protein-Associated Neurodegeneration) is an early onset movement disorder characterized by ataxia, dysarthria, and optic atrophy. Here we report the creation of a mouse model of MEPAN with patient-similar compound heterozygous mutations in the Mecr gene. The MEPAN mouse recapitulates the major hallmarks of MEPAN, including a movement disorder, optic neuropathy, defects in protein lipoylation, and reduced mitochondrial oxidative phosphorylation in the brain. MECR catalyzes the last step in mitochondrial fatty acid synthesis (mtFASII), and the mechanism by which loss of mtFASII leads to neurological disease is unknown. LC-MS/MS based proteomic analysis of Mecr mutant cerebella identified loss of subunits of complex I of oxidative phosphorylation (OXPHOS) and subunits of the iron sulfur cluster assembly (ISC) complex. Native gels revealed altered OXPHOS complex and supercomplex formation, and changes in binding of the acyl carrier protein (ACP) to mitochondrial complexes. These results demonstrate that MECR plays a key role in the acylation of ACP which is necessary for ACP-LYRM mediated supercomplex modulation and ISC biogenesis and suggest new pathways for therapeutics.
| MSV000099206 | MassIVE
Project description:Autosomal optic atrophy (AOA) is a form of hereditary optic neuropathy characterized by the irreversible and progressive degermation of the retinal ganglion cells. Most cases of AOA are associated with a single dominant mutation in OPA1, which encodes a protein required for fusion of the inner mitochondrial membrane. It is unclear how loss of OPA1 leads to neuronal death, and despite ubiquitous expression appears to disproportionately affect the RGCs. This study introduces two novel in vivo models of OPA1-mediated AOA, including the first developmentally viable vertebrate Opa1 knockout (KO). These models allow for the study of Opa1 loss in neurons, specifically RGCs. Though survival is significantly reduced in Opa1 deficient zebrafish and Drosophila, both models permit the study of viable larvae. Moreover, zebrafish Opa1 KO larvae show impaired visual function but unchanged locomotor function, indicating that retinal neurons are particularly sensitive to Opa1 loss. Proteomic profiling of both models reveals marked disruption in protein expression associated with mitochondrial function, consistent with an observed decrease in mitochondrial respiratory function. Similarly, mitochondrial fragmentation and disordered cristae organization were observed in neuronal axons in both models highlighting Opa1’s highly conserved role in regulating mitochondrial morphology and function in neuronal axons. Importantly, in Opa1 deficient zebrafish, mitochondrial disruption and visual impairment precede degeneration of RGCs. These novel models mimic key features of AOA and provide valuable tools for therapeutic screening. Our findings suggest that therapies enhancing mitochondrial function may offer a potential treatment strategy for AOA.
2025-05-07 | PXD059584 | Pride
Project description:Autosomal optic atrophy (AOA) is a form of hereditary optic neuropathy characterized by the irreversible and progressive degermation of the retinal ganglion cells. Most cases of AOA are associated with a single dominant mutation in OPA1, which encodes a protein required for fusion of the inner mitochondrial membrane. It is unclear how loss of OPA1 leads to neuronal death, and despite ubiquitous expression appears to disproportionately affect the RGCs. This study introduces two novel in vivo models of OPA1-mediated AOA, including the first developmentally viable vertebrate Opa1 knockout (KO). These models allow for the study of Opa1 loss in neurons, specifically RGCs. Though survival is significantly reduced in Opa1 deficient zebrafish and Drosophila, both models permit the study of viable larvae. Moreover, zebrafish Opa1 KO larvae show impaired visual function but unchanged locomotor function, indicating that retinal neurons are particularly sensitive to Opa1 loss. Proteomic profiling of both models reveals marked disruption in protein expression associated with mitochondrial function, consistent with an observed decrease in mitochondrial respiratory function. Similarly, mitochondrial fragmentation and disordered cristae organization were observed in neuronal axons in both models highlighting Opa1’s highly conserved role in regulating mitochondrial morphology and function in neuronal axons. Importantly, in Opa1 deficient zebrafish, mitochondrial disruption and visual impairment precede degeneration of RGCs. These novel models mimic key features of AOA and provide valuable tools for therapeutic screening. Our findings suggest that therapies enhancing mitochondrial function may offer a potential treatment strategy for AOA.
2025-05-07 | PXD059645 | Pride
Project description:Mitochondrial disease is a debilitating condition with a diverse genetic aetiology. Here, we report that TMEM126A, a protein that is mutated in patients with autosomal recessive optic atrophy, participates directly in the assembly of mitochondrial complex I. Using a combination of genome editing, interaction studies and quantitative proteomics, we find that loss of TMEM126A results in an isolated complex I deficiency and that TMEM126A interacts with a number of complex I subunits and assembly factors. Pulse-labelling interaction studies reveal that TMEM126A associates with the newly synthesised mtDNA-encoded ND4 subunit of complex I. Our findings indicate that TMEM126A is involved in the assembly of the ND4 distal membrane module of complex I. Importantly, we clarify that the function of TMEM126A is distinct from its paralogue TMEM126B, which acts in assembly of the ND2-module of complex I, helping to explain the differences in disease aetiology observed between these two genes.
2021-04-21 | PXD023136 | Pride