Project description:Clonal hematopoiesis of indeterminate potential is prevalent in elderly individuals and associated with increased risks of all-cause mortality and cardiovascular disease. However, mouse models to study the dynamics of clonal hematopoiesis and its consequences on the cardiovascular system under homeostatic conditions are lacking. We used a model of clonal hematopoiesis using adoptive transfer of unfractionated ten-eleven translocation 2-mutant (Tet2-mutant) bone marrow cells into nonirradiated mice. Consistent with age-related clonal hematopoiesis observed in humans, these mice displayed a progressive expansion of Tet2-deficient cells in multiple hematopoietic stem and progenitor cell fractions and blood cell lineages. The expansion of the Tet2-mutant fraction was also observed in bone marrow-derived CCR+ myeloid cell populations within the heart, but there was a negligible impact on the yolk sac-derived CCR2- cardiac resident macrophage population. Transcriptome profiling revealed an enhanced inflammatory signature in the donor-derived macrophages isolated from the heart. Mice receiving Tet2-deficient bone marrow cells spontaneously developed age-related cardiac dysfunction characterized by greater hypertrophy and fibrosis. Altogether, we show that Tet2- mediated hematopoiesis contributes to cardiac dysfunction in a nonconditioned setting that faithfully models the human clonal hematopoiesis in unperturbed bone marrow. Our data support clinical findings that clonal hematopoiesis per se may contribute to diminished health span.
Project description:Here, we use single cell sequencing to elucidate the role and heterogeniety of the bone marrow cells in clonal hematopoiesis. We have identified key CD74/CD206 macrophage populations that play a role in early clonal propagation of Tet2+/- cells and analyzed their expression at both week 1 and week 22 of clonal hematopoiesis progression.
Project description:Ion channel splice array data from cerebellum brain tissue samples collected from Alzheimer's disease patients. Temporal cortex (Alzheimer's disease affected brain tissue structure) and cerebellum (Alzheimer's disease unaffected brain tissue structure) samples from control subjects were compared to temporal cortex and cerebellum of patients with Alzheimer's disease.
Project description:Coronavirus disease 2019 (COVID-19) is associated with significant morbidity and mortality, albeit with considerable heterogeneity among affected individuals. Emerging evidence points towards an important role of preexisting host factors, such as a deregulated inflammatory response at the time of infection. Here, we demonstrate the negative impact of clonal hematopoiesis, a prevalent clonal disorder of ageing individuals, on COVID-19-related cytokine release severity and mortality. In this study we perform use the Illumina MethylationEPIC array to quantify methylation levels in PBMCs from COVID19 patients and patients with clonal hematopoiesis.
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:DNA damage and mutations in hematopoietic stem cells (HSC) enable clonal hematopoiesis (CH). Such damage occurs throughout life, but its origins remain unknown. Here, we demonstrate that endogenous formaldehyde causes HSC attrition and subsequently CH. We generated conditional mouse models lacking formaldehyde detoxification and Fanconi anemia (FA) DNA repair in blood. Formaldehyde protection was crucial from embryonic HSC emergence and throughout life. Despite a severe deficiency in HSCs, these mice produce blood for many months. To determine what enables this, we employed a new unbiased method for detecting clones which exploits somatic variant data. This revealed initial polyclonal hematopoiesis which diminishes to monoclonal CH, devoid of known genetic selection. Furthermore, in FA children, we find the same transition to monoclonal hematopoiesis. Therefore, DNA damage-induced attrition down to a last functional cell can be a driving force for CH, representing an alternative route to CH other than purely by fitness-enhancing selection.