Peroxisomal multifunctional protein 2 deficiency perturbs lipid homeostasis in the retina causing visual dysfunction in mice
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PROVIDER: PRJNA687498 | ENA |
REPOSITORIES: ENA
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Project description:Patients lacking multifunctional protein 2, the central enzyme of the peroxisomal β-oxidation pathway, develop retinopathy. This metabolic pathway is involved in the metabolism of very long chain (VLCFAs) and polyunsaturated (PUFAs) fatty acids, which are enriched in the photoreceptor outer segments (POS). The molecular mechanisms underlying the retinopathy remain however elusive. Here, we report that Mfp2-/- mice display decreased retinal function already at the age of 3 weeks, which is accompanied by a profound shortening of the photoreceptor outer and inner segments, but with preserved photoreceptor ultrastructure. Furthermore, Mfp2-/- retinas exhibit severe changes in gene expression with downregulation of genes involved in the phototransduction pathway and upregulation of inflammation related genes. Lipid profiling of the retina of Mpf2-/- mice revealed a profound reduction of DHA-containing phospholipids. This was likely due to a hampered systemic supply and retinal traffic of this PUFA, although we cannot exclude that the local defect of peroxisomal β-oxidation contributes to this DHA decrease. Moreover, VLC-PUFAs were also reduced, except those containing ≥34 carbons that accumulated. The latter suggests that there is an uncontrollable elongation of retinal PUFAs. In conclusion, we showed that intact peroxisomal β-oxidation is indispensable for retinal integrity, most likely by maintaining PUFA homeostasis.
2021-01-31 | GSE163770 | GEO
Project description:Patients lacking multifunctional protein 2 (MFP2), the central enzyme of the peroxisomal ?-oxidation pathway, develop retinopathy. This pathway is involved in the metabolism of very long chain (VLCFAs) and polyunsaturated (PUFAs) fatty acids, which are enriched in the photoreceptor outer segments (POS). The molecular mechanisms underlying the retinopathy remain, however, elusive. Here, we report that mice with MFP2 inactivation display decreased retinal function already at the age of 3 weeks, which is accompanied by a profound shortening of the photoreceptor outer and inner segments, but with preserved photoreceptor ultrastructure. Furthermore, MFP2 deficient retinas exhibit severe changes in gene expression with downregulation of genes involved in the phototransduction pathway and upregulation of inflammation related genes. Lipid profiling of the mutant retinas revealed a profound reduction of DHA-containing phospholipids. This was likely due to a hampered systemic supply and retinal traffic of this PUFA, although we cannot exclude that the local defect of peroxisomal ?-oxidation contributes to this DHA decrease. Moreover, very long chain PUFAs were also reduced, with the exception of those containing ? 34 carbons that accumulated. The latter suggests that there is an uncontrollable elongation of retinal PUFAs. In conclusion, our data reveal that intact peroxisomal ?-oxidation is indispensable for retinal integrity, most likely by maintaining PUFA homeostasis.
| S-EPMC7884615 | biostudies-literature
Project description:Distinct retrograde signaling pathways have been identified for several cellular organelles. These pathways are important to maintain the function of these organelles in response to organelle-specific stress. Using Caenorhabditis elegans, we show for the first time that such a retrograde signaling also exists for peroxisomes. Analysis of the C. elegans transcriptome revealed that peroxisomal import stress caused by the knock-down of the peroxisomal matrix protein import receptor prx-5/PEX5 induces the compensatory up-regulation of genes involved in defense response and lipid metabolic processes, especially peroxisomal beta oxidation. We, therefore, propose that the peroxisomal retrograde signaling participates in the maintenance of peroxisomal function in response to peroxisomal import stress.
2020-12-19 | GSE156318 | GEO
Project description:Peroxisomes play an essential role in the β-oxidation of dicarboxylic acids (DCAs), which are metabolites formed upon ω-oxidation of fatty acids. The physiological functions of DCA metabolism remain largely unknown. In this study, we aimed to evaluate the biological role of DCA metabolism using mice deficient in the peroxisomal L-bifunctional protein (Ehhadh KO mice). We performed RNA-seq in WT and Ehhadh KO livers, treated with vehicle or L-aminocarnitine (L-AC), an inhibitor of mitochondrial fatty acid oxidation. We show that, in liver, Ehhadh KO mice have increased mRNA and protein expression of cholesterol biosynthesis enzymes with decreased (in females) or similar (in males) rate of cholesterol synthesis. We conclude that EHHADH plays an essential role in the metabolism of medium-chain DCAs and postulate that peroxisomal DCA β-oxidation is a regulator of hepatic cholesterol biosynthesis.
2021-04-02 | GSE171292 | GEO
Project description:Murine deficiency of peroxisomal L-bifunctional protein (EHHADH) causes medium-chain 3-hydroxydicarboxylic aciduria and perturbs hepatic cholesterol homeostasis
| PRJNA719096 | ENA
Project description:Pigment regeneration is critical for the function of cone photoreceptors in bright and rapidly-changing light conditions. This process is facilitated by the recently-characterized retina visual cycle, in which Müller cells recycle spent all-trans-retinol visual chromophore back to 11-cis-retinol. This 11-cis-retinol is oxidized selectively in cones to the 11-cis-retinal used for pigment regeneration. However, the enzyme responsible for the oxidation of 11-cis-retinol remains unknown. Here, we sought to determine whether retinol dehydrogenase 10 (RDH10), upregulated in rod/cone hybrid retinas and expressed abundantly in Müller cells, is the enzyme that drives this reaction. We created mice lacking RDH10 either in cone photoreceptors, Müller cells, or the entire retina. In vivo electroretinography and transretinal recordings revealed normal cone photoresponses in all RDH10-deficient mouse lines. Notably, their cone-driven dark adaptation both in vivo and in isolated retina was unaffected, indicating that RDH10 is not required for the function of the retina visual cycle. We also generated transgenic mice expressing RDH10 ectopically in rod cells. However, rod dark adaptation was unaffected by the expression of RDH10 and transgenic rods were unable to use cis-retinol for pigment regeneration. We conclude that RDH10 is not the dominant retina 11-cis-RDH, leaving its primary function in the retina unknown.
2017-03-07 | GSE86442 | GEO
Project description:Peroxisomal retrograde signaling in C. elegans
| PRJNA657442 | ENA
Project description:The aim is to study the function of peroxisomal NAD-malate dehydrogenase in fatty acid beta-oxidation, glyoxylate cycle and photorespiration. Both peroxisomal MDH genes (At2g22780 and At5g09660) have been knocked out with T-DNA insertions and a double mutant made. Double mutant seedlings are blocked in beta-oxidation - they are 2,4DB resistant and beta-oxidation genes are repressed. They carry out glyoxylate cycle as normal. Plants grow well in soil and produce seed. Microarray analysis will tell us the extent of changes in gene expression in the mutant. For microarray analysis seeds are stratified at 4 C on agar medium with 1/2 strength M&S salts and 1% sucrose for 2 days, then seedlings grown for 2 days at 20 C in the light (100 umol/m2/s). Triplicate samples will be grown for mutant and wild type (col-0) and RNA isolated from each. Experimenter name = Itsara Pracharoenwattana Experimenter phone = 0131 650 5316 Experimenter fax = 0131 650 5392 Experimenter department = Institute of Molecular Plant Sciences Experimenter institute = University of Edinburgh Experimenter address = Daniel Rutherford Building University of Edinburgh Experimenter address = The King's Buildings Experimenter address = Edinburgh Experimenter zip/postal_code = EH9 3JH Experimenter country = UK Keywords: genetic_modification_design
2007-01-08 | GSE5641 | GEO
Project description:Brain development is orchestrated by both innate and experience-dependent mechanisms, but their relative contributions are often difficult to resolve. Here we asked if and how central visual areas are altered in a vertebrate brain depleted of any and all signals from retinal ganglion cells throughout development. We transcriptionally profiled neurons in pretectum, thalamus and other retinorecipient areas of larval zebrafish and searched for changes in lakritz mutants that lack all retinal connections. Although individual genes are dysregulated, the complete set of 77 neuronal types develops in apparently normal proportions, at normal locations, and along normal differentiation trajectories. Strikingly, the cell-cycle exits of proliferating progenitors in these areas are delayed, and a greater fraction of early postmitotic precursors remain uncommitted or are diverted to a glial fate. Optogenetic stimulation targeting groups of neurons normally involved in processing visual information evokes behaviors indistinguishable from wildtype. In conclusion, we show that signals emitted by retinal axons influence the pace of neurogenesis in visual areas, but do not detectably affect the specification or wiring of downstream neurons.
2023-10-02 | GSE238240 | GEO
Project description:The aim is to study the function of peroxisomal NAD-malate dehydrogenase in fatty acid beta-oxidation, glyoxylate cycle and photorespiration. Both peroxisomal MDH genes (At2g22780 and At5g09660) have been knocked out with T-DNA insertions and a double mutant made. Double mutant seedlings are blocked in beta-oxidation - they are 2,4DB resistant and beta-oxidation genes are repressed. They carry out glyoxylate cycle as normal. Plants grow well in soil and produce seed. Microarray analysis will tell us the extent of changes in gene expression in the mutant. For microarray analysis seeds are stratified at 4 C on agar medium with 1/2 strength M&S salts and 1% sucrose for 2 days, then seedlings grown for 2 days at 20 C in the light (100 umol/m2/s). Triplicate samples will be grown for mutant and wild type (col-0) and RNA isolated from each. Experimenter name = Itsara Pracharoenwattana; Experimenter phone = 0131 650 5316; Experimenter fax = 0131 650 5392; Experimenter department = Institute of Molecular Plant Sciences; Experimenter institute = University of Edinburgh; Experimenter address = Daniel Rutherford Building University of Edinburgh; Experimenter address = The King's Buildings; Experimenter address = Edinburgh; Experimenter zip/postal_code = EH9 3JH; Experimenter country = UK Experiment Overall Design: 6 samples were used in this experiment
2008-06-13 | E-GEOD-5641 | biostudies-arrayexpress