Multi-omic analysis of chronic myelomonocytic leukemia monocytes reveals metabolic and immune dysregulation leading to altered macrophage polarization [ATACseq]
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ABSTRACT: Chronic myelomonocytic leukemia (CMML) is a myelodysplastic/myeloproliferative overlap neoplasm with few treatment options and generally poor prognosis. A defining feature is expansion of classical monocytes, which are responsible for various clinical sequelae and thus represent viable therapeutic targets. Given the near-ubiquity of mutations involving epigenetic regulators, we profiled the epigenome (open chromatin configuration; H3K4-monomethylation; H3K27-acetylation; H3K27/H3K4-trimethylation) and transcriptome of primary CD14+ monocytes from CMML patients and age-matched healthy controls. Compared with healthy monocytes, CMML monocytes displayed heterogeneous but distinct epigenetic and transcriptome signatures. Most epigenetic changes mapped to distal elements, suggesting generalized enhancer dysregulation. We observed strong epigenetic (but not transcriptional) suppression of the NF-κB pathway, suggesting poised potential to repress downstream targets and modulate inflammatory responses. RNA-seq revealed up-regulation of genes involved in the oxidative phosphorylation (OxPhos) machinery, with significantly heightened OxPhos activity of primary CMML monocytes validated in mitochondrial stress tests, highlighting a potentially tractable therapeutic vulnerability. In line with the observed metabolic phenotype of CMML monocytes, unpolarized CMML monocyte-derived macrophages exhibited transcriptional bias towards an M2 (“anti-inflammatory”) phenotype, reflected by an increased Th2/Th1 ratio in comparison with control monocytes. These observations may be germane to the observed clinical heterogeneity and prominent immune dysfunction characteristic of CMML.
Project description:Chronic myelomonocytic leukemia (CMML) is a myelodysplastic/myeloproliferative overlap neoplasm with few treatment options and generally poor prognosis. A defining feature is expansion of classical monocytes, which are responsible for various clinical sequelae and thus represent viable therapeutic targets. Given the near-ubiquity of mutations involving epigenetic regulators, we profiled the epigenome (open chromatin configuration; H3K4-monomethylation; H3K27-acetylation; H3K27/H3K4-trimethylation) and transcriptome of primary CD14+ monocytes from CMML patients and age-matched healthy controls. Compared with healthy monocytes, CMML monocytes displayed heterogeneous but distinct epigenetic and transcriptome signatures. Most epigenetic changes mapped to distal elements, suggesting generalized enhancer dysregulation. We observed strong epigenetic (but not transcriptional) suppression of the NF-κB pathway, suggesting poised potential to repress downstream targets and modulate inflammatory responses. RNA-seq revealed up-regulation of genes involved in the oxidative phosphorylation (OxPhos) machinery, with significantly heightened OxPhos activity of primary CMML monocytes validated in mitochondrial stress tests, highlighting a potentially tractable therapeutic vulnerability. In line with the observed metabolic phenotype of CMML monocytes, unpolarized CMML monocyte-derived macrophages exhibited transcriptional bias towards an M2 (“anti-inflammatory”) phenotype, reflected by an increased Th2/Th1 ratio in comparison with control monocytes. These observations may be germane to the observed clinical heterogeneity and prominent immune dysfunction characteristic of CMML.
Project description:Chronic myelomonocytic leukemia (CMML) is a myelodysplastic/myeloproliferative overlap neoplasm with few treatment options and generally poor prognosis. A defining feature is expansion of classical monocytes, which are responsible for various clinical sequelae and thus represent viable therapeutic targets. Given the near-ubiquity of mutations involving epigenetic regulators, we profiled the epigenome (open chromatin configuration; H3K4-monomethylation; H3K27-acetylation; H3K27/H3K4-trimethylation) and transcriptome of primary CD14+ monocytes from CMML patients and age-matched healthy controls. Compared with healthy monocytes, CMML monocytes displayed heterogeneous but distinct epigenetic and transcriptome signatures. Most epigenetic changes mapped to distal elements, suggesting generalized enhancer dysregulation. We observed strong epigenetic (but not transcriptional) suppression of the NF-κB pathway, suggesting poised potential to repress downstream targets and modulate inflammatory responses. RNA-seq revealed up-regulation of genes involved in the oxidative phosphorylation (OxPhos) machinery, with significantly heightened OxPhos activity of primary CMML monocytes validated in mitochondrial stress tests, highlighting a potentially tractable therapeutic vulnerability. In line with the observed metabolic phenotype of CMML monocytes, unpolarized CMML monocyte-derived macrophages exhibited transcriptional bias towards an M2 (“anti-inflammatory”) phenotype, reflected by an increased Th2/Th1 ratio in comparison with control monocytes. These observations may be germane to the observed clinical heterogeneity and prominent immune dysfunction characteristic of CMML.
Project description:Human embryonic stem (HUES) cells are derived from early individual embryos with unique genetic properties. However, how their epigenetic status might affect their potential to differentiate toward specific lineages remains a puzzling question. Using ChIP-on-chip, the status of bivalent domains on gene promoters (i.e. H3K4 and H3K27 trimethylation) was monitored for both undifferentiated and BMP2 induced cardiac committed cells. A marked difference in the epigenetic profile of HUES cell lines was observed and this was correlated to the pattern of gene expression induced by BMP2 as well as to their potential to generate cardiac progenitors and differentiated myocytes. Thus, the epigenetic H3trimeK4 and H3trimeK27 prints generating bivalent domains on promoters, could be used to predict a preference in their differentiation toward a specific lineage. Using ChIP-on-chip, the status of bivalent domains on gene promoters (i.e. H3K4 and H3K27 trimethylation) was monitored for both undifferentiated and BMP2 induced cardiac committed cells.
Project description:Chronic myelomonocytic leukemia (CMML) is an aggressive myeloid neoplasm of older individuals characterized by persistent monocytosis. Somatic mutations in CMML are heterogeneous and only partially explain the variability in clinical outcomes. Recent data suggest that cardiovascular morbidity is increased in CMML and contributes to reduced survival. Clonal hematopoiesis of indeterminate potential (CHIP), the presence of mutated blood cells in hematologically normal individuals, is a precursor of age-related myeloid neoplasms and associated with increased cardiovascular risk. To isolate CMML-specific alterations from those related to aging, we performed RNA sequencing and DNA methylation profiling on purified monocytes from CMML patients and from age-matched (old) and young healthy controls. We found that the transcriptional signature of CMML monocytes is highly pro-inflammatory, with upregulation of multiple inflammatory pathways, including tumor necrosis factor, IL-6 and IL-17 signaling, while age per se does not significantly contribute to this pattern. We observed no consistent correlations between aberrant gene expression and CpG island methylation, suggesting that pro-inflammatory signaling in CMML monocytes is governed by multiple and complex regulatory mechanisms. We propose that pro-inflammatory monocytes may contribute to cardiovascular morbidity in CMML patients, and promote progression by selection of mutated cell clones. Our data raise questions whether asymptomatic CMML patients may benefit from monocyte-depleting or anti-inflammatory therapies.
Project description:Identification of EGR1 chromatin localization in human primary monocytes (2 donors), in human primary monocytes from 2 CMML patients with TET2 truncating mutations (high VAF) and in human primary monocytes from 1 CMML patients with TET2 truncating mutations with low VAF.
Project description:Epigenetic alterations of monocytes from COVID-19 convalescent individuals and healthy controls have been analyzed by mapping trimethylated H3K4 (H3K4me3) and acetylated H3K27 (H3K27ac) genome-wide using CUT&RUN (Skene & Henikoff, 2017). Epigenetic reprogramming of myeloid cells represents a hallmark of trained innate immunity (Netea, Joosten et al., 2016). In general, active enhancers are marked by H3K27ac and transcription start sites are marked by H3K4me3 and H3K27ac (Kimura, 2013). A global analysis of histone modifications associated with transcription start sites (TSS) revealed a difference in the overall coverage of specific loci in SC-conv versus SC-naïve cells with SC-conv samples showing lower occupancy overall
Project description:We used chromatin immunoprecipitation-coupled to deep sequencing (ChIP-seq) to profile genome-wide locations of H3K4 trimethylation (H3K4me3) and H3K27 trimethylation (H3K27me3) epigenetic marks in SATB1-depleted MDA-MB-231 aggressive breast cells.
Project description:Mouse models of chronic myeloid malignancies suggest that targeting mature cells of the malignant clone disrupts feedback loops that promote disease expansion. Here, we show that, in chronic myelomonocytic leukemia (CMML), monocytes that accumulate in the peripheral blood show a decreased propensity to die by apoptosis. BH3 profiling demonstrates their addiction to MCL1 (myeloid cell leukemia-1), which can be targeted with the small molecule inhibitor S63845. RNA sequencing and DNA methylation pattern analysis both point also to the implication of the MAPK (mitogen-activated protein kinase) pathway in the resistance of CMML monocytes to death and reveal an autocrine pathway in which the secreted cytokine CYTL1 (Cytokine-like protein 1) promotes ERK (extracellular signal-regulated kinase) activation through CCR2 (C-C chemokine receptor type 2). Combined MAPK and MCL1 inhibition restores apoptosis of CMML patient monocytes and reduces the expansion of patient-derived xenografts in mice. These results designate the combined inhibition of MCL1 and MAPK as a promising approach to slow down CMML progression by inducing leukemic monocyte apoptosis.
Project description:Mouse models of chronic myeloid malignancies suggest that targeting mature cells of the malignant clone disrupts feedback loops that promote disease expansion. Here, we show that, in chronic myelomonocytic leukemia (CMML), monocytes that accumulate in the peripheral blood show a decreased propensity to die by apoptosis. BH3 profiling demonstrates their addiction to MCL1 (myeloid cell leukemia-1), which can be targeted with the small molecule inhibitor S63845. RNA sequencing and DNA methylation pattern analysis both point also to the implication of the MAPK (mitogen-activated protein kinase) pathway in the resistance of CMML monocytes to death and reveal an autocrine pathway in which the secreted cytokine CYTL1 (Cytokine-like protein 1) promotes ERK (extracellular signal-regulated kinase) activation through CCR2 (C-C chemokine receptor type 2). Combined MAPK and MCL1 inhibition restores apoptosis of CMML patient monocytes and reduces the expansion of patient-derived xenografts in mice. These results designate the combined inhibition of MCL1 and MAPK as a promising approach to slow down CMML progression by inducing leukemic monocyte apoptosis.
Project description:Multipotential naïve CD4+ T cells differentiate into distinct lineages including T helper 1 (Th1), Th2, Th17, and inducible T regulatory (iTreg) cells. The remarkable diversity of CD4+ T cells begs the question whether the observed changes reflect terminal differentiation with heritable epigenetic modifications or plasticity in T cell responses. We generated genome-wide histone H3 lysine 4 (H3K4) and lysine 27 (H3K27) trimethylation maps in naïve, Th1, Th2, Th17, iTreg, and natural (n)Treg cells. We found that although modifications of signature cytokine genes (Ifng, Il4, and Il17) partially conform to the expectation of lineage commitment, critical transcription factors such as Tbx21 exhibit a broad spectrum of epigenetic states, consistent with our demonstration of T-bet and IFN-? induction in nTreg cells. Our data suggest an epigenetic mechanism underlying the specificity and plasticity of effector and regulatory T cells and also provide a framework for understanding complexity of CD4+ T helper cell differentiation. Experiment Overall Design: Different T helper subsets are profiled for mRNA expression.