Project description:To investigate the influence the partial loss of Tet1 has on AD pathogenesis in 5xFAD mice, we crossed a Tet1 KO mouse line with the 5xFAD mouse line to generate WT, 5xFAD, Tet1(+/-), and FAD/Tet1(+/-) mice.
Project description:To investigate the influence the partial loss of Tet1 has on AD pathogenesis in 5xFAD mice, we crossed a Tet1 KO mouse line with the 5xFAD mouse line to generate WT, 5xFAD, Tet1(+/-), and FAD/Tet1(+/-) mice. We then performed gene expression profiling analysis using data obtained from RNA-seq from biological replicates of mice comprised of 4 different genotypes.
Project description:No disease-modifying drugs exist to treat osteoarthritis (OA), a degenerative disease of the joint. The complexity of OA necessitates a combinational and broad therapeutic approach. Epigenetic regulators are able to control large programs of genes, and recent work from our group and others have showcased systemic epigenetic dysregulation in OA. Previously, we demonstrated that OA chondrocytes accumulate 5-fold more 5-hydroxymethylcytosine (5hmC), an oxidized derivative of methylcytosine (5mC) associated with gene activation, at disease relevant sites. To test if 5hmC has a role in the early onset of OA, we utilized a mouse model of surgically induced OA, destabilization of the medial meniscus (DMM), and found that DMM mice gained ~40,000 differentially hydroxymethylated sites. Genetic loss of TET1, the enzyme responsible for 5hmC deposition, prevented pathologic gain of 5hmC, activation of many OA pathways, and protected mice from OA development. To test the clinical potential of a TET1 based OA therapy, we injected 2-hydroxyglutarate (2-HG), a TET inhibitor, into the joint after DMM induction and observed stalled disease progression. Collectively, these data show that TET1 mediated 5hmC deposition regulates multiple OA pathways and that its modulation can be a powerful clinical tool for OA.
Project description:Alzheimer's disease (AD) is a chronic neurodegenerative disorder characterized by progressive deterioration of cognitive function. Evidence suggests a role for epigenetic regulation, in particular the cytosine modifications 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC,) in AD. 5hmC is highly enriched in the nervous system and displays neurodevelopment and age-related changes. To determine the role of 5hmC in AD, we performed genome-wide analyses of 5hmC in DNA from prefrontal cortex of post-mortem AD as well as RNA-Seq to correlate changes in methylation status with transcriptional changes. We also utilized the existing AD fly model to further test the functional significance of these epigenetically altered loci. We identified 325 genes containing differentially hydroxymethylated loci (DhMLs) in both the discovery and replication datasets, and these are enriched for pathways involved in neuron projection development and neurogenesis. Of the 325 genes identified, 140 also showed changes in gene expression by RNA-Seq. Proteins encoded by genes identified in the current analysis form direct protein-protein interactions with AD-associated genes, expanding the network of genes implicated in AD. Furthermore, we identified AD-associated single nucleotide polymorphisms (SNPs) located within or near DhMLs, suggesting that these SNPs may identify regions of epigenetic gene regulation that play a role in AD pathogenesis. Finally using the existing AD fly model we showed that some of these genes could modulate the toxicity associated with AD. Our data implicate neuron projection development and neurogenesis pathways as potential targets in AD. These results indicate that incorporating epigenomic and transcriptomic data with GWAS data can expand the known network of genes involved in disease pathogenesis. Combination of epigenome profiling and Drosophila model enables us to identify the epigenetic modifiers of Alzheimer's disease. University of Kentucky Alzheimer's Disease Research Center (3 control, 3 Alzheimer's) and Emory University Alzheimer's Disease Research Center (2 control, 2 Alzheimer's)
Project description:Precise regulation of DNA methylation in mammals is critical for genome stability and epigenetic regulation. The discovery of the ten-eleven translocation (TET) proteins catalyzing the oxidation from 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC) revolutionized the perspective on the complexity and regulation of DNA modifications. Despite accumulating knowledge about the role of TET1, it remains unclear to what extent these can be attributed to its catalytic activity. Here, we use genome engineering and quantitative multi-omics approaches to dissect the role and mechanism of TET1 in mESCs. Our study identifies TET1 as an essential interaction hub for multiple chromatin modifying complexes and as a global regulator of histone modifications. Strikingly, we find that the majority of transcriptional regulation depends on non-catalytic functions of TET1. Moreover, we show that the establishment of H3K9me3 and H4K20me3 at ERV1, ERVK, and ERVL is mediated by TET1 independent of DNA demethylation. We provide evidence that repression of endogenous retroviruses depends on the interaction between TET1 and SIN3A. In summary, we demonstrate that the non-catalytic functions of TET1 are critical for regulation of gene expression and the silencing of endogenous retroviruses in mESCs.
Project description:DNA hydroxymethylation by epigenetic modifiers TET dioxygenases is critical for gene transcription in various biological processes, however, its role in oligodendrocyte maturation and functions remain elusive. Here, we found that mice lacking Tet1 in the oligodendrocyte lineage exhibited hypomyelination in the CNS in the juvenile stage, leading to defects in action potential propagation, motor coordination, anxiety-like behavior and spatial memory capacities. Although the myelin deficiency recovered in adulthood, remyelination after cuprizone-induced demyelination was compromised in Tet1cKO mice. By integrating transcriptome and DNA methylation profiles, we identified a cohort of genes that were differentially regulated by Tet1 and hyperhydroxymethylation, including the genes associated with Ca2+ transportation. Tet1-deficient OPCs exhibited a reduction in [Ca2+] oscillations, while the agonists of calcium internal stores rescued the differentiation defect of Tet1-deficient OPCs. Thus, our results suggest that stage-specific Tet1-mediated epigenetic programming in oligodendrocytes maintain Ca2+ homeostasis for differentiation and regulate neuronal activities and myelin repair.
Project description:No disease-modifying drugs exist to treat osteoarthritis (OA), a degenerative disease of the joint. The complexity of OA necessitates a combinational and broad therapeutic approach. Epigenetic regulators are able to control large programs of genes, and recent work from our group and others have showcased systemic epigenetic dysregulation in OA. Previously, we demonstrated that OA chondrocytes accumulate 5-fold more 5-hydroxymethylcytosine (5hmC), an oxidized derivative of methylcytosine (5mC) associated with gene activation, at disease relevant sites. To test if 5hmC has a role in the early onset of OA, we utilized a mouse model of surgically induced OA, destabilization of the medial meniscus (DMM), and found that DMM mice gained ~40,000 differentially hydroxymethylated sites. Genetic loss of TET1, the enzyme responsible for 5hmC deposition, prevented pathologic gain of 5hmC, activation of many OA pathways, and protected mice from OA development. To test the clinical potential of a TET1 based OA therapy, we injected 2-hydroxyglutarate (2-HG), a TET inhibitor, into the joint after DMM induction and observed stalled disease progression. Collectively, these data show that TET1 mediated 5hmC deposition regulates multiple OA pathways and that its modulation can be a powerful clinical tool for OA.