Tafazzin-Deficient Zebrafish Display Mitochondrial Dysfunction and Metabolic Defects Without Myopathy
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PROVIDER: PRJNA1194115 | ENA |
REPOSITORIES: ENA
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Project description:Barth syndrome is a rare X-linked syndrome characterized by cardiomyopathy, skeletal myopathy, and neutropenia. This life-threatening disorder results from loss of function mutations in TAFAZZIN, which encodes a phospholipid-lysophospholipid transacylase located in the mitochondria inner membrane. Decreased cardiolipin levels and increased monolysocardiolipin levels perturb mitochondrial function. However, the mechanism(s) leading to myopathies and neutropenia are unknown, and there is currently no effective therapy for Barth syndrome. To address these knowledge gaps, we generated tafazzin-deficient zebrafish. Neutropenia developed as early as 5 days post-fertilization, but surprisingly no cardiac or skeletal myopathies were detected into adulthood. Yet, mitochondrial dysfunction in tafazzin mutants led to decreased ATP production. Metabolomic analysis revealed notable changes, including increased levels of lactic acid, decreased glucose, and widespread effects on amino acid and unsaturated fatty acid synthesis. Despite these metabolic disturbances, the zebrafish displayed a normal lifespan and fertility. Cardiolipin abnormalities were detected in both larvae and adult tissues, specifically in the heart and whole kidney marrow. Surprisingly, adult tafazzin mutants exhibited a higher number of neutrophils compared to wildtype fish. Further investigation revealed signs of inflammation as evidenced by elevated levels of il6 in the whole kidney marrows and hearts of adult fish. Our comprehensive studies demonstrated that while mitochondrial dysfunction and metabolic defects were evident in tafazzin-deficient zebrafish, these disturbances did not significantly affect their development nor survival. These findings suggest that zebrafish may possess salvage pathways which compensate for Tafazzin loss or that humans have a unique vulnerability to the loss of TAFAZZIN.
2025-07-03 | GSE283499 | GEO
Project description:Analysis of the transcriptome of cardiac tissue from mice trangenically engineered with a doxycycline inducible Tafazzin shRNA knockdown to mimic the loss of function of Tafazzin in Barth syndrome. ShRNA induced knockdown mice were compared to wildtype littermates also fed the doxycyline diet. The hypothesis was to investigate adaptive metabolic and compensatory gene transcriptional changes in myocardium of the mouse model of Barth syndrome Total RNA obtained from 2 month old cardiac tissue from the doxycycline inducible shRNA Tafazzin knockdown mouse model of Barth syndrome compared to wildtype littermates also fed 625 mg/Kg doxycycline diet
2011-11-05 | E-GEOD-33452 | biostudies-arrayexpress
Project description:Inhibiting tafazzin a cardiolipin remodeling enzyme reduces stemness of AML by modulating the level of phosphatidylserine
2019-03-28 | GSE107045 | GEO
Project description:Tafazzin is a transacylase which causes the content and molecular structure of cardiolipin (CL) to be altered in the inner mitochondrial membrane. The enzymatic machinery responsible for oxidative respiration are localized to the inner mitochondrial membrane and require CL for activity. As a result, tafazzin is critical for maintaining mitochondrial function. In beta-cells, which are the insulin secreting cells in pancreatic islets, mitochondrial function is linked to insulin secretion. We previously established that tafazzin knock-down mice were lean and maintained insulin sensitivity compared to the obese insulin resistant control litter mates. However, it was unknown whether tafazzin deficiency also influenced insulin secretion in the establishment of the lean phenotype. Using X week-old mice, we ascertained that the number of beta-cells was similar between genotypes. Ex vivo insulin secretion under low glucose conditions was reduced (52%) from islets isolated from tafazzin knock-down mice. Consistent with this tafazzin knock-down mice exhibited reduced fasting insulin plasma insulin levels. Measurement of mitochondrial oxygen consumption revealed that basal oxygen consumption was reduced (58%) in islets from tafazzin-deficient animals. The addition of etomoxir, an inhibitor of mitochondrial fatty acid translocation, significantly elevated basal mitochondrial respiration (5-fold) in islets from tafazzin knockdown mice, indicating a significant fatty acid-mediated inhibitory effect. In contrast, etomoxir lacked any measurable effect on control wild-type islets. The altered mitochondrial function identified in taffazin knock-down islets was not associated with reduced CL content or elevated oxyCL species. Our experiments indicate that tafazzin plays a key role in regulating normal islet beta-cell function.
2021-07-31 | GSE136242 | GEO
Project description:Mitochondria fulfill vital metabolic functions and act as crucial cellular signaling hubs integrating their metabolic status into the cellular context. Here, we show that defective cardiolipin-remodeling, upon loss of the cardiolipin acyl transferase Tafazzin, mutes HIF-1a signaling in hypoxia. Tafazzin-deficiency does not affect posttranslational HIF-1a regulation but rather HIF-1a gene-expression, a dysfunction recapitulated in iPSCs-derived cardiomyocytes from Barth Syndrome patients with Tafazzin-deficiency. RNAseq analyses confirmed drastically altered signaling in Tafazzin mutant cells. In hypoxia, Tafazzin-deficient cells display reduced production of reactive oxygen species (ROS) perturbing NF-kB activation and concomitantly HIF-1a gene-expression. In agreement, Tafazzin-deficient mice hearts display reduced HIF-1a levels and undergo maladaptive hypertrophy with heart failure in response to pressure overload challenge. We conclude that defective mitochondrial cardiolipin-remodeling dampens HIF-1a signaling through inactivation of a non-canonical signaling pathway: Lack of NF-kB activation through reduced mitochondrial ROS production diminishes HIF-1a transcription.
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Project description:Congenital ptosis, a genetic disorder involving levator palpebrae muscle dysfunction, is often associated with congenital myopathy. The genetic causes of this condition remain poorly understood. In this study, we identified FOXK2 mutations in six pedigrees with congenital myopathy and ptosis through whole exome sequencing and Sanger sequencing. Zebrafish with foxk2 deficiency exhibited underdeveloped skeletal muscles and reduced mobility, while mice with Foxk2 deletion in skeletal muscle stem cells (MuSCs) showed generalized skeletal muscle abnormalities. Further analysis revealed that FOXK2 deficiency impaired myogenic differentiation in C2C12 cells and disrupted mitochondrial homeostasis in both mouse MuSCs and C2C12 cells. Rescue experiments confirmed the loss-of-function effects of FOXK2 mutation. Coenzyme Q10 treatment improved mitochondrial function and alleviated skeletal muscle development defects in Foxk2-deficient mice. Preliminary omics analysis suggested FOXK2 directly regulates the expression of mitochondrial function-related genes by modulating chromatin accessibility at its binding sites. Our study identifies FOXK2 as a novel pathogenic gene for congenital myopathy with ptosis and highlights its essential role in skeletal muscle development and mitochondrial homeostasis, offering insights for potential diagnostics and therapies.
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Project description:Skeletal muscle fiber composition and muscle energetics are not static and change in muscle disease. This study was performed to determine if a mitochondrial myopathy is associated with adjustments in skelatal fiber type composition. These effects of drug induced mitochondrial dysfunction on skeletal muscle fiber type composition were analyzed in an animal model.
2012-10-18 | E-MEXP-3642 | biostudies-arrayexpress
Project description:Evaluate changes in gene expression resulting from the loss of the gene TAZ (protein tafazzin). Tafazzin is an enzyme involved in cardiolipin maturation and cardiolipin is a phospholipid found only in the inner mitochondrial membrane. Gene expression profiling was performed in a murine granulocyte-monocyte progenitor in vitro cell system. We identified a limited number of changes in gene expression, which was not surprising given that the tafazzin protein is localized in the mitochondria and has a very specific enzymatic activity. Genes involved in cholesterol and fatty acid metabolism (Acss1, Acat2, Ldlr), apoptosis (Bcl2, Casp3, Casp6, Cycs), and ER-stress induced apoptosis (Ddit3, Atf4) were differentially expressed.
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Project description:We performed a genome-wide association study in pooled DNA samples from patients with severe statin myopathy and persistent symptoms post-therapy versus pooled DNAs from an age-adjusted statin-tolerant group. Affymetrix 100K SNP arrays were used according to the manufacturers instructions with two pools of 19 and 20 statin myopathy patients and two pools of 20 statin-tolerant controls.
2010-07-09 | E-GEOD-17574 | biostudies-arrayexpress
Project description:Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal-dominant condition that is characterised by a progressive degeneration and weakness of skeletal muscle fibers. The underlying cause of FSHD has been attributed to inappropriate expression of the transcription factor double homeobox (Dux); however, the mechanisms leading to myopathy in response to Dux expression remain incompletely understood. To study the acute effects of Dux activation in mammalian skeletal muscle fibers, we generated a recombinant adeno-associated viral vector allowing tunable Dux expression. Consistent with previous findings, we confirmed that the ectopic expression of Dux in mouse skeletal muscle results in a degenerative myopathy. Building on these findings, we observed that the acute expression of Dux in muscle fibers causes profound transcriptome changes prior to the onset of pathology. Furthermore, muscles expressing Dux display elevated levels of the TGF-beta superfamily member, Myostatin and increased Smad2/3 activity. Notably, inhibition of Myostatin is sufficient to prevent Dux-induced myopathy. Collectively, these findings support further investigation of interventions targeting the Myostatin-Smad2/3 pathway as prospective approaches to treating myopathy associated with Dux mis-expression.
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