Longitudinal dynamics of clonal haematopoiesis identifies gene-specific fitness effects
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PROVIDER: PRJNA812679 | ENA |
REPOSITORIES: ENA
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Project description:The prevalence of clonal haematopoiesis of indeterminate potential (CHIP) in healthy individuals increases rapidly from age 60 onwards and has been associated with increased risk for malignancy, heart disease and ischemic stroke. CHIP is driven by somatic mutations in stem cells that are also drivers of myeloid malignancies. Since mutations in stem cells often drive leukaemia, we hypothesised that stem cell fitness substantially contributes to transformation from CHIP to leukaemia. Stem cell fitness is defined as the proliferative advantage over cells carrying no or only neutral mutations. It is currently unknown whether mutations in different CHIP genes lead to distinct fitness advantages that could form the basis for patient stratification. We set out to quantify the fitness effects of CHIP drivers over a 12-year timespan in older age, using longitudinal error-corrected sequencing data. Two key results support the possibility for individualised clinical monitoring of CHIP: (i) We developed a new filtering method to extract fitness effects from longitudinal data using Bayesian inference, while taking into account individual mutational context and co-occurrence of mutations, and thus quantify the growth potential of variants within each individual. (ii) We show that gene-specific fitness differences can outweigh inter-individual variation and therefore could form the basis for personalised clinical management in the future.
2022-05-03 | GSE178936 | GEO
Project description:Clonal hematopoiesis of indeterminate potential (CHIP) increases rapidly in prevalence beyond age 60 and has been associated with increased risk for malignancy, heart disease and ischemic stroke. CHIP is driven by somatic mutations in hematopoietic stem and progenitor cells (HSPCs). Because mutations in HSPCs often drive leukemia, we hypothesized that HSPC fitness substantially contributes to transformation from CHIP to leukemia. HSPC fitness is defined as the proliferative advantage over cells carrying no or only neutral mutations. If mutations in different genes lead to distinct fitness advantages, this could enable patient stratification. We quantified the fitness effects of mutations over 12 years in older age using longitudinal sequencing and developed a filtering method that considers individual mutational context alongside mutation co-occurrence to quantify the growth potential of variants within individuals. We found that gene-specific fitness differences can outweigh inter-individual variation and, therefore, could form the basis for personalized clinical management.
| S-EPMC9307482 | biostudies-literature
Project description:Clonal expansions driven by somatic mutations become pervasive across human tissues with age, including in the haematopoietic system, where the phenomenon is termed clonal haematopoiesis1-4. The understanding of how and when clonal haematopoiesis develops, the factors that govern its behaviour, how it interacts with ageing and how these variables relate to malignant progression remains limited5,6. Here we track 697 clonal haematopoiesis clones from 385 individuals 55 years of age or older over a median of 13 years. We find that 92.4% of clones expanded at a stable exponential rate over the study period, with different mutations driving substantially different growth rates, ranging from 5% (DNMT3A and TP53) to more than 50% per year (SRSF2P95H). Growth rates of clones with the same mutation differed by approximately ±5% per year, proportionately affecting slow drivers more substantially. By combining our time-series data with phylogenetic analysis of 1,731 whole-genome sequences of haematopoietic colonies from 7 individuals from an older age group, we reveal distinct patterns of lifelong clonal behaviour. DNMT3A-mutant clones preferentially expanded early in life and displayed slower growth in old age, in the context of an increasingly competitive oligoclonal landscape. By contrast, splicing gene mutations drove expansion only later in life, whereas TET2-mutant clones emerged across all ages. Finally, we show that mutations driving faster clonal growth carry a higher risk of malignant progression. Our findings characterize the lifelong natural history of clonal haematopoiesis and give fundamental insights into the interactions between somatic mutation, ageing and clonal selection.
| S-EPMC9177423 | biostudies-literature
Project description:Certain somatic mutations confer a fitness advantage in hematopoietic stem cells, resulting in the clonal expansion of mutant blood cells, known as clonal haematopoiesis (CH). Among the top 3 CH mutations, ASXL1 mutations present the highest risk for developing cardiovascular diseases (CVDs). However, how ASXL1 mutations induce CVDs remains totally elusive. Here we show that haematopoietic cells harbouring C-terminally truncated form of ASXL1 mutant (ASXL1-MT) accelerated development of atherosclerosis in Ldlr–/– mice. Transcriptome analyses of plaque-cells showed inflammatory signatures of monocytes and macrophages expressing ASXL1-MT. Mechanistically, wild-type ASXL1 inhibited innate immune signalling through the inhibition of IRAK1-TAK1 interaction in the cytoplasm, indicating an unexpected non-epigenetic role of ASXL1. In contrast, ASXL1-MT lost this regulatory function, leading to NF-κB activation. Intriguingly, IRAK1/4 inhibition decreased inflammatory monocytes and atherosclerosis driven by ASXL1-MT. The present work connects ASXL1 mutations with inflammation and CVDs, giving a clue to prevent CVDs in ASXL1-CH.
2024-10-25 | GSE279450 | GEO
Project description:To study longitudinal dynamics of IGH BCR repertoires and clonal lineages evolution of memory B-cells, plasmablasts and plasma cells from peripheral blood of healthy donors, which were sampled three times within a year
2022-09-15 | E-MTAB-11193 | biostudies-arrayexpress
Project description:Certain somatic mutations confer a fitness advantage in hematopoietic stem cells, resulting in the clonal expansion of mutant blood cells, known as clonal haematopoiesis (CH). Among the top 3 CH mutations, ASXL1 mutations present the highest risk for developing cardiovascular diseases (CVDs). However, how ASXL1 mutations induce CVDs remains totally elusive. Here we show that haematopoietic cells harbouring C-terminally truncated form of ASXL1 mutant (ASXL1-MT) accelerated development of atherosclerosis in Ldlr–/– mice. Transcriptome analyses of plaque-cells showed inflammatory signatures of monocytes and macrophages expressing ASXL1-MT. Mechanistically, wild-type ASXL1 inhibited innate immune signalling through the inhibition of IRAK1-TAK1 interaction in the cytoplasm, indicating an unexpected non-epigenetic role of ASXL1. In contrast, ASXL1-MT lost this regulatory function, leading to NF-κB activation. Intriguingly, IRAK1/4 inhibition decreased inflammatory monocytes and atherosclerosis driven by ASXL1-MT. The present work connects ASXL1 mutations with inflammation and CVDs, giving a clue to prevent CVDs in ASXL1-CH.
2024-10-25 | GSE279601 | GEO
Project description:Clonal hematopoiesis (CH) results from enhanced fitness of a mutant hematopoietic stem and progenitor cell (HSPC), but how such clones expand is unclear. Here, we developed a technique that combines mosaic mutagenesis with color labeling of HSPCs to study how acquired mutations affect clonal fitness in a native environment. Mutations in CH-associated genes, like asxl1, promoted clonal dominance. Single-cell transcriptional analysis revealed that mutations stimulated expression of proinflammatory genes in mature myeloid cells and anti-inflammatory genes in progenitor cells of the mutant clone. Biallelic loss of one such immunomodulator, nr4a1, abrogated the ability of asxl1-mutant clones to establish clonal dominance. These results support a model where clonal fitness of mutant clones is driven by enhanced resistance to inflammatory signals from their mutant mature cell progeny.
2021-12-02 | GSE176036 | GEO
Project description:Clonal hematopoiesis (CH) results from enhanced fitness of a mutant hematopoietic stem and progenitor cell (HSPC), but how such clones expand is unclear. Here, we developed a technique that combines mosaic mutagenesis with color labeling of HSPCs to study how acquired mutations affect clonal fitness in a native environment. Mutations in CH-associated genes, like asxl1, promoted clonal dominance. Single-cell transcriptional analysis revealed that mutations stimulated expression of proinflammatory genes in mature myeloid cells and anti-inflammatory genes in progenitor cells of the mutant clone. Biallelic loss of one such immunomodulator, nr4a1, abrogated the ability of asxl1-mutant clones to establish clonal dominance. These results support a model where clonal fitness of mutant clones is driven by enhanced resistance to inflammatory signals from their mutant mature cell progeny.
2021-12-02 | GSE150373 | GEO
Project description:The study will measure blood population dynamics in abnormal human haematopoiesis in patients with clonal blood stem cell disorders.
| EGAS00001003181 | EGA
Project description:All cancers emerge following a period of clonal selection and subsequent clonal expansion. Whilst the evolutionary principles imparted by genetic intra-tumour heterogeneity (ITH) are becoming increasingly clear, little is known about the non-genetic mechanisms that contribute to ITH and malignant clonal fitness. Using SPLINTR, a synthetic expressed barcoding strategy, in three clinically relevant mouse models of acute myeloid leukaemia (AML) we find that malignant clonal dominance is a stable and heritable property that is facilitated by the repression of antigen presentation and the increased expression of Slpi, a leukocyte protease inhibitor that has not previously been characterised in AML. Increased transcriptional heterogeneity is a consistent feature enabling clonal fitness in diverse tissue / immune microenvironments and in the context of clonal competition between genetically distinct clones within a uniform microenvironment. Compared to extramedullary sites, leukaemia initiating capacity is most enriched in malignant cells resident within the bone marrow microenvironment and leukaemia stem cells (LSC), like normal haematopoietic stem cells, display heritable clone-intrinsic properties of high, and low clonal output that contribute to the overall tumour mass. Finally, we demonstrate that clonal output does not dictate sensitivity to chemotherapy and both high and low output LSC clones retain marked cellular plasticity enabling them to survive potent therapeutic challenge and persist as minimal residual disease. Together these data provide fundamental insights into the non-genetic transcriptional processes that underpin malignant clonal fitness which may inform future therapeutic strategies.
2021-11-08 | GSE161673 | GEO