Search results for "optic atrophy"
showing 10 items of 14 documents
Enhanced autophagic-lysosomal activity and increased BAG3-mediated selective macroautophagy as adaptive response of neuronal cells to chronic oxidati…
2019
Oxidative stress and a disturbed cellular protein homeostasis (proteostasis) belong to the most important hallmarks of aging and of neurodegenerative disorders. The proteasomal and autophagic-lysosomal degradation pathways are key measures to maintain proteostasis. Here, we report that hippocampal cells selected for full adaptation and resistance to oxidative stress induced by hydrogen peroxide (oxidative stress-resistant cells, OxSR cells) showed a massive increase in the expression of components of the cellular autophagic-lysosomal network and a significantly higher overall autophagic activity. A comparative expression analysis revealed that distinct key regulators of autophagy are upregu…
Autosomal-Recessive Mutations in AP3B2, Adaptor-Related Protein Complex 3 Beta 2 Subunit, Cause an Early-Onset Epileptic Encephalopathy with Optic At…
2016
International audience; Early-onset epileptic encephalopathy (EOEE) represents a heterogeneous group of severe disorders characterized by seizures, interictal epileptiform activity with a disorganized electroencephalography background, developmental regression or retardation, and onset before 1 year of age. Among a cohort of 57 individuals with epileptic encephalopathy, we ascertained two unrelated affected individuals with EOEE associated with developmental impairment and autosomal-recessive variants in AP3B2 by means of whole-exome sequencing. The targeted sequencing of AP3B2 in 86 unrelated individuals with EOEE led to the identification of an additional family. We gathered five addition…
Lon protease: a novel mitochondrial matrix protein in the interconnection between drug-induced mitochondrial dysfunction and endoplasmic reticulum st…
2017
Background and Purpose Mitochondria-associated membranes (MAMs) are specific endoplasmic reticulum (ER) domains that enable it to interact directly with mitochondria and mediate metabolic flow and Ca2+ transfer. A growing list of proteins have been identified as MAMs components, but how they are recruited and function during complex cell stress situations is still not understood, while the participation of mitochondrial matrix proteins is largely unrecognized. Experimental Approach This work compares mitochondrial/ER contact during combined ER stress/mitochondrial dysfunction using a model of human hepatoma cells (Hep3B cell line) treated for 24 h with classic pharmacological inducers of ER…
Point mutations associated with Leber hereditary optic neuropathy in a Latvian population
2013
Purpose To study mutations associated with Leber hereditary optic neuropathy (LHON) in patients suspected of having this mitochondrial disorder in a Latvian population. Additional aims were to determine the heteroplasmy status of all non-synonymous polymorphisms identified in the current study and to identify the mitochondrial haplogroups of the studied participants because these factors may contribute to the manifestation of LHON. Methods Twelve patients, including patients in two families, were enrolled in the current study. LHON was suspected based on the findings of ophthalmologic examinations. In clinically affected individuals, the presence of all previously reported LHON-associated m…
Analysis of BNIP3 and BNIP3L/Nix expression in cybrid cell lines harboring two LHON-associated mutations.
2019
Mitochondria are key players in cell death through the activation of the intrinsic apoptosis pathway. BNIP3 and BNIP3L/Nix are outer mitochondrial membrane bifunctional proteins which because of containing both BH3 and LIR domains play a role in cellular response to stress by regulation of apoptosis and selective autophagy. Leber’s Hereditary Optic Neuropathy (LHON) is the most common mitochondrial disease in adults, characterized by painless loss of vision caused by atrophy of the optic nerve. The disease in over 90% of cases is caused by one of three mutations in the mitochondrial genome: 11778G>A, 3460G>A or 14484T>C. The pathogenic processes leading to optic nerve degeneration …
Simulating Images Seen by Patients with Inhomogeneous Sensitivity Losses
2012
PURPOSE We aim to simulate how colored images are perceived by subjects with local achromatic and chromatic contrast sensitivity losses in the visual field (VF). METHODS The spatiochromatic corresponding pair algorithm, introduced in a previous article (J Opt Soc Am (A) 2004;21:176-186), has been implemented with a linear model of the visual system. Spatial information is processed separately by the chromatic and achromatic mechanisms by means of a multiscale model, with sensors selective to frequency, orientation, and spatial position, whose mechanism-dependent relative weights change with the spatial location of the image. These weights have been obtained from perimetric data from a patie…
Down-regulation of OPA1 alters mouse mitochondrial morphology, PTP function, and cardiac adaptation to pressure overload
2012
AIMS: The optic atrophy 1 (OPA1) protein is an essential protein involved in the fusion of the mitochondrial inner membrane. Despite its high level of expression, the role of OPA1 in the heart is largely unknown. We investigated the role of this protein in Opa1(+/-) mice, having a 50% reduction in OPA1 protein expression in cardiac tissue. METHODS AND RESULTS: In mutant mice, cardiac function assessed by echocardiography was not significantly different from that of the Opa1(+/+). Electron and fluorescence microscopy revealed altered morphology of the Opa1(+/-) mice mitochondrial network; unexpectedly, mitochondria were larger with the presence of clusters of fused mitochondria and altered c…
Usher syndrome and Leber congenital amaurosis are molecularly linked via a novel isoform of the centrosomal ninein-like protein.
2009
Contains fulltext : 80984.pdf (Publisher’s version ) (Closed access) Usher syndrome (USH) and Leber congenital amaurosis (LCA) are autosomal recessive disorders resulting in syndromic and non-syndromic forms of blindness. In order to gain insight into the pathogenic mechanisms underlying retinal degeneration, we searched for interacting proteins of USH2A isoform B (USH2A(isoB)) and the LCA5-encoded protein lebercilin. We identified a novel isoform of the centrosomal ninein-like protein, hereby named Nlp isoform B (Nlp(isoB)), as a common interactor. Although we identified the capacity of this protein to bind calcium with one of its three EF-hand domains, the interacton with USH2A(isoB) did …
Mutations in LCA5, encoding the ciliary protein lebercilin, cause Leber congenital amaurosis
2007
Contains fulltext : 53618.pdf (Publisher’s version ) (Closed access) Leber congenital amaurosis (LCA) causes blindness or severe visual impairment at or within a few months of birth. Here we show, using homozygosity mapping, that the LCA5 gene on chromosome 6q14, which encodes the previously unknown ciliary protein lebercilin, is associated with this disease. We detected homozygous nonsense and frameshift mutations in LCA5 in five families affected with LCA. In a sixth family, the LCA5 transcript was completely absent. LCA5 is expressed widely throughout development, although the phenotype in affected individuals is limited to the eye. Lebercilin localizes to the connecting cilia of photore…
Mitochondrial dynamics in type 2 diabetes: Pathophysiological implications
2017
Mitochondria play a key role in maintaining cellular metabolic homeostasis. These organelles have a high plasticity and are involved in dynamic processes such as mitochondrial fusion and fission, mitophagy and mitochondrial biogenesis. Type 2 diabetes is characterised by mitochondrial dysfunction, high production of reactive oxygen species (ROS) and low levels of ATP. Mitochondrial fusion is modulated by different proteins, including mitofusin-1 (MFN1), mitofusin-2 (MFN2) and optic atrophy (OPA-1), while fission is controlled by mitochondrial fission 1 (FIS1), dynamin-related protein 1 (DRP1) and mitochondrial fission factor (MFF). PARKIN and (PTEN)-induced putative kinase 1 (PINK1) partici…