29 research outputs found
Dominant ACO2 mutations are a frequent cause of isolated optic atrophy.
Biallelic mutations in ACO2, encoding the mitochondrial aconitase 2, have been identified in individuals with neurodegenerative syndromes, including infantile cerebellar retinal degeneration and recessive optic neuropathies (locus OPA9). By screening European cohorts of individuals with genetically unsolved inherited optic neuropathies, we identified 61 cases harbouring variants in ACO2, among whom 50 carried dominant mutations, emphasizing for the first time the important contribution of ACO2 monoallelic pathogenic variants to dominant optic atrophy. Analysis of the ophthalmological and clinical data revealed that recessive cases are affected more severely than dominant cases, while not significantly earlier. In addition, 27% of the recessive cases and 11% of the dominant cases manifested with extraocular features in addition to optic atrophy. In silico analyses of ACO2 variants predicted their deleterious impacts on ACO2 biophysical properties. Skin derived fibroblasts from patients harbouring dominant and recessive ACO2 mutations revealed a reduction of ACO2 abundance and enzymatic activity, and the impairment of the mitochondrial respiration using citrate and pyruvate as substrates, while the addition of other Krebs cycle intermediates restored a normal respiration, suggesting a possible short-cut adaptation of the tricarboxylic citric acid cycle. Analysis of the mitochondrial genome abundance disclosed a significant reduction of the mitochondrial DNA amount in all ACO2 fibroblasts. Overall, our data position ACO2 as the third most frequently mutated gene in autosomal inherited optic neuropathies, after OPA1 and WFS1, and emphasize the crucial involvement of the first steps of the Krebs cycle in the maintenance and survival of retinal ganglion cells
Vectorization of cisplatin by nanoparticles based in nucleolipids
Le cisplatine est lâun des trois agents anticancĂ©reux les plus utilisĂ©s en chimiothĂ©rapie contre les tumeurs solides. Cependant, les doses utilisĂ©es sont limitĂ©es par des effets secondaires importants et lâexistence des rĂ©sistances innĂ©es ou acquises vis-Ă -vis de cette drogue. Ce travail vise Ă augmenter lâindex thĂ©rapeutique du cisplatine (rĂ©duire ses effets secondaires et augmenter son activitĂ© anti-tumorale). Pour cela des nanoparticules hautement chargĂ©es en cisplatine en couche par couche Ă base de nuclĂ©olipides ont Ă©tĂ© prĂ©parĂ©es. Les Ă©tudes physico-chimiques (TEM, DLS, XPS, microscopie Ă fluorescence, ICP-optique) ont rĂ©vĂ©lĂ© que les nanoparticules Ă double couche Ă©taient plus stables en milieu biologique par rapport aux formulations en mono-couche. Les Ă©tudes biologiques rĂ©alisĂ©es sur deux lignĂ©es tumorales ovariennes (IGROV1 et SKOV3) ont montrĂ© que cette formulation amĂ©liore lâactivitĂ© cytotoxique du cisplatine et inhibe le dĂ©veloppement des rĂ©sistances. LâĂ©tude du mĂ©canisme dâaction (internalisation, apoptose, gĂ©notoxicitĂ©, rĂ©plication de lâADN) a confirmĂ© que les nanoparticules Ă double couche augmentent le taux de cisplatine internalisĂ© qui, une fois libĂ©rĂ© dans les cellules, arrĂȘte la rĂ©plication de lâADN et induit la mort cellulaire par apoptose. Aucune toxicitĂ© intrinsĂšque aux nano-objets nâest observĂ©e. Les Ă©tudes in vivo de ces nanoparticules Ă double couche aprĂšs injection en intraveineuse de 5, 7 et 9 mg/Kg ont rĂ©vĂ©lĂ© que cette formulation augmente la dose maximale tolĂ©rĂ©e et prĂ©sente une activitĂ© anti-tumorale vis-Ă -vis des lignĂ©es cellulaires PROb et GV1A1. Cette stratĂ©gie dâĂ©laboration des nanoparticules en couche par couche de nuclĂ©olipides nous a permis dâinsĂ©rer des PEG avec ou sans acide folique pour le ciblage et dâintroduire une deuxiĂšme drogue lipophile, le paclitaxel. Les tests in vitro (cytotoxicitĂ©, internalisation) ont montrĂ© lâintĂ©rĂȘt de ces modifications.Cisplatin is one of the three most commonly used anticancer drugs in chemotherapy against solid tumors. However, the doses used are limited by significant side effects and the existence of resistance. The aim of this work is to increase the therapeutic index of cisplatin. For this purpose, highly charged nucleolipids nanoparticles âlayer-by-layerâ of cisplatin were prepared. The physico-chemical studies (TEM, DLS, XPS, ICP, Fluorescence microscopy) revealed that the bilayer nanoparticles were more stable in biological environment compared with mono-layer formulations. Biological studies carried in two ovarian carcinoma cells lines (IGROV1 and SKOV3) showed that this formulation enhances the cytotoxic activity of cisplatin and inhibits the development of resistance. The study of the mechanism of action (internalization, apoptosis, genotoxicity, DNA replication) demonstrated the nanoparticles with double layer increases the rate of cisplatin internalized then released into the cells, stops the replication of DNA and induces cell death by apoptosis. No intrinsic toxicity of nano-objects is observed. In vivo studies of these nanoparticles double layer after intravenous injection of 5, 7 and 9 mg/Kg in the rats showed this formulation increases the maximum tolerated dose and has an antitumor activity against PROb en GV1A1 cells lines. This strategy of developing layer-by-layer nucleolipids nanoparticles allows to insert PEG with or without folic acid for targeting and introducing second drug, a lipophilic paclitaxel. In vitro study (cytotoxicity, internalization) have shown the benefits of both modification
Vectorization of cisplatin by nanoparticles based in nucleolipids
Le cisplatine est lâun des trois agents anticancĂ©reux les plus utilisĂ©s en chimiothĂ©rapie contre les tumeurs solides. Cependant, les doses utilisĂ©es sont limitĂ©es par des effets secondaires importants et lâexistence des rĂ©sistances innĂ©es ou acquises vis-Ă -vis de cette drogue. Ce travail vise Ă augmenter lâindex thĂ©rapeutique du cisplatine (rĂ©duire ses effets secondaires et augmenter son activitĂ© anti-tumorale). Pour cela des nanoparticules hautement chargĂ©es en cisplatine en couche par couche Ă base de nuclĂ©olipides ont Ă©tĂ© prĂ©parĂ©es. Les Ă©tudes physico-chimiques (TEM, DLS, XPS, microscopie Ă fluorescence, ICP-optique) ont rĂ©vĂ©lĂ© que les nanoparticules Ă double couche Ă©taient plus stables en milieu biologique par rapport aux formulations en mono-couche. Les Ă©tudes biologiques rĂ©alisĂ©es sur deux lignĂ©es tumorales ovariennes (IGROV1 et SKOV3) ont montrĂ© que cette formulation amĂ©liore lâactivitĂ© cytotoxique du cisplatine et inhibe le dĂ©veloppement des rĂ©sistances. LâĂ©tude du mĂ©canisme dâaction (internalisation, apoptose, gĂ©notoxicitĂ©, rĂ©plication de lâADN) a confirmĂ© que les nanoparticules Ă double couche augmentent le taux de cisplatine internalisĂ© qui, une fois libĂ©rĂ© dans les cellules, arrĂȘte la rĂ©plication de lâADN et induit la mort cellulaire par apoptose. Aucune toxicitĂ© intrinsĂšque aux nano-objets nâest observĂ©e. Les Ă©tudes in vivo de ces nanoparticules Ă double couche aprĂšs injection en intraveineuse de 5, 7 et 9 mg/Kg ont rĂ©vĂ©lĂ© que cette formulation augmente la dose maximale tolĂ©rĂ©e et prĂ©sente une activitĂ© anti-tumorale vis-Ă -vis des lignĂ©es cellulaires PROb et GV1A1. Cette stratĂ©gie dâĂ©laboration des nanoparticules en couche par couche de nuclĂ©olipides nous a permis dâinsĂ©rer des PEG avec ou sans acide folique pour le ciblage et dâintroduire une deuxiĂšme drogue lipophile, le paclitaxel. Les tests in vitro (cytotoxicitĂ©, internalisation) ont montrĂ© lâintĂ©rĂȘt de ces modifications.Cisplatin is one of the three most commonly used anticancer drugs in chemotherapy against solid tumors. However, the doses used are limited by significant side effects and the existence of resistance. The aim of this work is to increase the therapeutic index of cisplatin. For this purpose, highly charged nucleolipids nanoparticles âlayer-by-layerâ of cisplatin were prepared. The physico-chemical studies (TEM, DLS, XPS, ICP, Fluorescence microscopy) revealed that the bilayer nanoparticles were more stable in biological environment compared with mono-layer formulations. Biological studies carried in two ovarian carcinoma cells lines (IGROV1 and SKOV3) showed that this formulation enhances the cytotoxic activity of cisplatin and inhibits the development of resistance. The study of the mechanism of action (internalization, apoptosis, genotoxicity, DNA replication) demonstrated the nanoparticles with double layer increases the rate of cisplatin internalized then released into the cells, stops the replication of DNA and induces cell death by apoptosis. No intrinsic toxicity of nano-objects is observed. In vivo studies of these nanoparticles double layer after intravenous injection of 5, 7 and 9 mg/Kg in the rats showed this formulation increases the maximum tolerated dose and has an antitumor activity against PROb en GV1A1 cells lines. This strategy of developing layer-by-layer nucleolipids nanoparticles allows to insert PEG with or without folic acid for targeting and introducing second drug, a lipophilic paclitaxel. In vitro study (cytotoxicity, internalization) have shown the benefits of both modification
Vectorisation du cisplatine via des nanoparticules à base de nucléolipides
Le cisplatine est l un des trois agents anticancĂ©reux les plus utilisĂ©s en chimiothĂ©rapie contre les tumeurs solides. Cependant, les doses utilisĂ©es sont limitĂ©es par des effets secondaires importants et l existence des rĂ©sistances innĂ©es ou acquises vis-Ă -vis de cette drogue. Ce travail vise Ă augmenter l index thĂ©rapeutique du cisplatine (rĂ©duire ses effets secondaires et augmenter son activitĂ© anti-tumorale). Pour cela des nanoparticules hautement chargĂ©es en cisplatine en couche par couche Ă base de nuclĂ©olipides ont Ă©tĂ© prĂ©parĂ©es. Les Ă©tudes physico-chimiques (TEM, DLS, XPS, microscopie Ă fluorescence, ICP-optique) ont rĂ©vĂ©lĂ© que les nanoparticules Ă double couche Ă©taient plus stables en milieu biologique par rapport aux formulations en mono-couche. Les Ă©tudes biologiques rĂ©alisĂ©es sur deux lignĂ©es tumorales ovariennes (IGROV1 et SKOV3) ont montrĂ© que cette formulation amĂ©liore l activitĂ© cytotoxique du cisplatine et inhibe le dĂ©veloppement des rĂ©sistances. L Ă©tude du mĂ©canisme d action (internalisation, apoptose, gĂ©notoxicitĂ©, rĂ©plication de l ADN) a confirmĂ© que les nanoparticules Ă double couche augmentent le taux de cisplatine internalisĂ© qui, une fois libĂ©rĂ© dans les cellules, arrĂȘte la rĂ©plication de l ADN et induit la mort cellulaire par apoptose. Aucune toxicitĂ© intrinsĂšque aux nano-objets n est observĂ©e. Les Ă©tudes in vivo de ces nanoparticules Ă double couche aprĂšs injection en intraveineuse de 5, 7 et 9 mg/Kg ont rĂ©vĂ©lĂ© que cette formulation augmente la dose maximale tolĂ©rĂ©e et prĂ©sente une activitĂ© anti-tumorale vis-Ă -vis des lignĂ©es cellulaires PROb et GV1A1. Cette stratĂ©gie d Ă©laboration des nanoparticules en couche par couche de nuclĂ©olipides nous a permis d insĂ©rer des PEG avec ou sans acide folique pour le ciblage et d introduire une deuxiĂšme drogue lipophile, le paclitaxel. Les tests in vitro (cytotoxicitĂ©, internalisation) ont montrĂ© l intĂ©rĂȘt de ces modifications.Cisplatin is one of the three most commonly used anticancer drugs in chemotherapy against solid tumors. However, the doses used are limited by significant side effects and the existence of resistance. The aim of this work is to increase the therapeutic index of cisplatin. For this purpose, highly charged nucleolipids nanoparticles layer-by-layer of cisplatin were prepared. The physico-chemical studies (TEM, DLS, XPS, ICP, Fluorescence microscopy) revealed that the bilayer nanoparticles were more stable in biological environment compared with mono-layer formulations. Biological studies carried in two ovarian carcinoma cells lines (IGROV1 and SKOV3) showed that this formulation enhances the cytotoxic activity of cisplatin and inhibits the development of resistance. The study of the mechanism of action (internalization, apoptosis, genotoxicity, DNA replication) demonstrated the nanoparticles with double layer increases the rate of cisplatin internalized then released into the cells, stops the replication of DNA and induces cell death by apoptosis. No intrinsic toxicity of nano-objects is observed. In vivo studies of these nanoparticles double layer after intravenous injection of 5, 7 and 9 mg/Kg in the rats showed this formulation increases the maximum tolerated dose and has an antitumor activity against PROb en GV1A1 cells lines. This strategy of developing layer-by-layer nucleolipids nanoparticles allows to insert PEG with or without folic acid for targeting and introducing second drug, a lipophilic paclitaxel. In vitro study (cytotoxicity, internalization) have shown the benefits of both modification.BORDEAUX2-Bib. Ă©lectronique (335229905) / SudocSudocFranceF
Are Your Mitochondria Ready for a Space Odyssey?
International audienceAnticipating very long space trips, da Silveira et al. performed pan-omic analyses on in-flight samples from astronauts, mice, and cells. Results revealed major mitochondrial dysfunctions responsible for alterations in metabolism, immunity, and circadian rhythm, which should prompt the evaluation of countermeasures to reduce the risks of future space odysseys, especially toward the planet Mars
Unexpected Bilayer Formation in Langmuir Films of Nucleolipids
Langmuir monolayers have been extensively investigated by various experimental techniques. These studies allowed an in-depth understanding of the molecular conformation in the layer, phase transitions, and the structure of the multilayer. As the monolayer is compressed and the surface pressure is increased beyond a critical value, usually occurring in the minimal closely packed molecular area, the monolayer fractures and/or folds, forming multilayers in a process referred to as collapse. Various mechanisms for monolayer collapse and the resulting reorganization of the film have been proposed, and only a few studies have demonstrated the formation of a bilayer after collapse and with the use of a Ca2+ solution. In this work, Langmuir isotherms coupled with imaging ellipsometry and polarization modulation infrared reflection absorption spectroscopy were recorded to investigate the airâwater interface properties of Langmuir films of anionic nucleolipids. We report for these new molecules the formation of a quasi-hexagonal packing of bilayer domains at a low compression rate, a singular behavior for lipids at the airâwater interface that has not yet been documented
Cancer/Testis Antigens into mitochondria: a hub between spermatogenesis, tumorigenesis and mitochondrial physiology adaptation
International audienceCancer/Testis Antigens (CTAs) genes are expressed only during spermatogenesis and tumorigenesis. Both processes share common specific metabolic adaptation related to energy supply, with a glucose to lactate gradient, leading to changes in mitochondrial physiology paralleling CTAs expression. In this review, we address the role of CTAs in mitochondria (mitoCTAs), by reviewing all published data, and assessing the putative localization of CTAs by screening for the presence of a mitochondrial targeting sequence (MTS). We evidenced that among the 276 CTAs, five were already shown to interfere with mitochondrial activities and 67 display a potential MTS
Anionic Nucleotide-Lipids for In Vitro DNA Transfection
A family of new anionic nucleotide based lipids featuring thymidine-3âČ-monophosphate as nucleotide and 1,2- diacyl-sn-glycerol as lipid moiety for in Vitro delivery of nucleic acids is described. The nucleotide lipids were prepared in three steps starting from 1,2-diacyl-sn-glycerols and 2âČ-deoxythymidine-3âČ-phosphoramidite. Gel electrophoresis experiments show that nucleotide-based lipid-DNA complexes are observed at Ca2+ concentration higher than 1 mM. The transfection experiments carried out on mammalian Hek cell lines clearly demonstrate that the nucleotide moiety enhances the transfection efficacy of the natural anionic DPPA and DPPG lipids. SAXS studies indicate that the enhancement in transfection for nucleotide-based lipid formulations compared to those of the abasic natural derivative (DPPA) is likely due to the presence of the 2D columnar inverted hexagonal phase (HII) with a unit cell parameter a ) 69.1 Ă
in the nucleotide lipid formulations. The cytotoxicity studies of lipoplexes, evaluated against Hek cells using an MTS assay, revealed that palmitoyl nucleotide derivative complexes were not toxic even after 4 h of incubation, thus indicating that the anionic nucleotide lipids presented in this work offer an alternative to cationic transfection reagents
CLUH granules coordinate translation of mitochondrial proteins with mTORC1 signaling and mitophagy
Mitochondria house anabolic and catabolic processes that must be balanced and adjusted to meet cellular demands. The RNA-binding protein CLUH (clustered mitochondria homolog) binds mRNAs of nuclear-encoded mitochondrial proteins and is highly expressed in the liver, where it regulates metabolic plasticity. Here, we show that in primary hepatocytes, CLUH coalesces in specific ribonucleoprotein particles that define the translational fate of target mRNAs, such as Pcx, Hadha, and Hmgcs2, to match nutrient availability. Moreover, CLUH granules play signaling roles, by recruiting mTOR kinase and the RNA-binding proteins G3BP1 and G3BP2. Upon starvation, CLUH regulates translation of Hmgcs2, involved in ketogenesis, inhibits mTORC1 activation and mitochondrial anabolic pathways, and promotes mitochondrial turnover, thus allowing efficient reprograming of metabolic function. In the absence of CLUH, a mitophagy block causes mitochondrial clustering that is rescued by rapamycin treatment or depletion of G3BP1 and G3BP2. Our data demonstrate that metabolic adaptation of liver mitochondria to nutrient availability depends on a compartmentalized CLUH-dependent post-transcriptional mechanism that controls both mTORC1 and G3BP signaling and ensures survival
Unexpected Bilayer Formation in Langmuir Films of Nucleolipids
Langmuir monolayers have been extensively investigated
by various
experimental techniques. These studies allowed an in-depth understanding
of the molecular conformation in the layer, phase transitions, and
the structure of the multilayer. As the monolayer is compressed and
the surface pressure is increased beyond a critical value, usually
occurring in the minimal closely packed molecular area, the monolayer
fractures and/or folds, forming multilayers in a process referred
to as collapse. Various mechanisms for monolayer collapse and the
resulting reorganization of the film have been proposed, and only
a few studies have demonstrated the formation of a bilayer after collapse
and with the use of a Ca<sup>2+</sup> solution. In this work, Langmuir
isotherms coupled with imaging ellipsometry and polarization modulation
infrared reflection absorption spectroscopy were recorded to investigate
the airâwater interface properties of Langmuir films of anionic
nucleolipids. We report for these new molecules the formation of a
quasi-hexagonal packing of bilayer domains at a low compression rate,
a singular behavior for lipids at the airâwater interface that
has not yet been documented