Project description:Accumulation of fatty bone marrow (FBM) is one of the key age related changes possibly influencing the blood system. While a link between obesity and cancer evolution has been reported it remains unknown whether FBM can modify the evolution of the early stages of leukemia and clonal hematopoiesis (CH). To address this question, we established different FBM mouse models in immunodeficient mice in whom we can study both mouse and human cells. We focused our studies on two FBM models: 1) after sublethal irradiation; 2) after castration; and in both we used an adipogenesis inhibitor as a control (PPARγ inhibitor). We transplanted both human and mice hematopoietic stem cells (HSCs) carrying DNMT3A mutations into immunodeficient mice with FBM. A significant increase in self-renewal was found when DNMT3AMut-HSCs were exposed to FBM. To better understand the mechanisms of the FBM-CH interaction, we performed single cell RNA-sequencing on HSPCs after FBM exposure in vivo. A 6-10 fold increase in DNMT3AMut-HSCs was observed under FBM conditions in comparison to normal bone marrow. Mutated HSCs from mice exposed to FBM exhibited an activated inflammatory signaling (IL-6 and IFNγ). Cytokine analysis of BM fluid and BM derived adipocytes grown in vitro demonstrated increased IL-6 levels under FBM conditions. Anti-IL-6 neutralizing antibodies significantly reduced the selective advantage of mice derived DNMT3AMut-HSCs exposed to FBM. Overall, paracrine FBM inflammatory signals promote DNMT3A-driven clonal hematopoiesis, which can be inhibited by blocking the IL-6 receptor.
Project description:Accumulation of fatty bone marrow (FBM) is one of the key age related changes possibly influencing the blood system. While a link between obesity and cancer evolution has been reported it remains unknown whether FBM can modify the evolution of the early stages of leukemia and clonal hematopoiesis (CH). To address this question, we established different FBM mouse models in immunodeficient mice in whom we can study both mouse and human cells. We focused our studies on two FBM models: 1) after sublethal irradiation; 2) after castration; and in both we used an adipogenesis inhibitor as a control (PPARγ inhibitor). We transplanted both human and mice hematopoietic stem cells (HSCs) carrying DNMT3A mutations into immunodeficient mice with FBM. A significant increase in self-renewal was found when DNMT3AMut-HSCs were exposed to FBM. To better understand the mechanisms of the FBM-CH interaction, we performed single cell RNA-sequencing on HSPCs after FBM exposure in vivo. A 6-10 fold increase in DNMT3AMut-HSCs was observed under FBM conditions in comparison to normal bone marrow. Mutated HSCs from mice exposed to FBM exhibited an activated inflammatory signaling (IL-6 and IFNγ). Cytokine analysis of BM fluid and BM derived adipocytes grown in vitro demonstrated increased IL-6 levels under FBM conditions. Anti-IL-6 neutralizing antibodies significantly reduced the selective advantage of mice derived DNMT3AMut-HSCs exposed to FBM. Overall, paracrine FBM inflammatory signals promote DNMT3A-driven clonal hematopoiesis, which can be inhibited by blocking the IL-6 receptor.
Project description:Accumulation of fatty bone marrow (FBM) is one of the key age related changes possibly influencing the blood system. While a link between obesity and cancer evolution has been reported it remains unknown whether FBM can modify the evolution of the early stages of leukemia and clonal hematopoiesis (CH). To address this question, we established different FBM mouse models in immunodeficient mice in whom we can study both mouse and human cells. We focused our studies on two FBM models: 1) after sublethal irradiation; 2) after castration; and in both we used an adipogenesis inhibitor as a control (PPARγ inhibitor). We transplanted both human and mice hematopoietic stem cells (HSCs) carrying DNMT3A mutations into immunodeficient mice with FBM. A significant increase in self-renewal was found when DNMT3AMut-HSCs were exposed to FBM. To better understand the mechanisms of the FBM-CH interaction, we performed single cell RNA-sequencing on HSPCs after FBM exposure in vivo. A 6-10 fold increase in DNMT3AMut-HSCs was observed under FBM conditions in comparison to normal bone marrow. Mutated HSCs from mice exposed to FBM exhibited an activated inflammatory signaling (IL-6 and IFNγ). Cytokine analysis of BM fluid and BM derived adipocytes grown in vitro demonstrated increased IL-6 levels under FBM conditions. Anti-IL-6 neutralizing antibodies significantly reduced the selective advantage of mice derived DNMT3AMut-HSCs exposed to FBM. Overall, paracrine FBM inflammatory signals promote DNMT3A-driven clonal hematopoiesis, which can be inhibited by blocking the IL-6 receptor.
Project description:Both fatty bone marrow (FBM) and somatic mutations in hematopoietic stem cells (HSCs), also termed clonal hematopoiesis (CH) accumulate with human aging. However it remains unclear whether FBM can modify the evolution of CH. To address this question, we herein present the interaction between CH and FBM in two preclinical male mouse models: after sub-lethal irradiation or after castration. An adipogenesis inhibitor (PPARγ inhibitor) is used in both models as a control. A significant increase in self-renewal can be detected in both human and rodent DNMT3AMut-HSCs when exposed to FBM. DNMT3AMut-HSCs derived from older mice interacting with FBM have even higher self-renewal in comparison to DNMT3AMut-HSCs derived from younger mice. Single cell RNA-sequencing on rodent HSCs after exposing them to FBM reveal a 6-10 fold increase in DNMT3AMut-HSCs and an activated inflammatory signaling. Cytokine analysis of BM fluid and BM derived adipocytes grown in vitro demonstrates an increased IL-6 levels under FBM conditions. Anti-IL-6 neutralizing antibodies significantly reduce the selective advantage of DNMT3AMut-HSCs exposed to FBM. Overall, paracrine FBM inflammatory signals promote DNMT3A-driven clonal hematopoiesis, which can be inhibited by blocking the IL-6 pathway.
Project description:Hematopoietic mutations in epigenetic regulators like DNA methyltransferase 3 alpha (DNMT3A) drive clonal hematopoiesis of indeterminate potential (CHIP) and are associated with adverse prognosis in patients with heart failure (HF). The interactions between CHIP-mutated cells and other cardiac cell types remain unknown. Here, we identify fibroblasts as potential interaction partners of CHIP-mutated monocytes using combined transcriptomic data from peripheral blood mononuclear cells of HF patients with and without CHIP and cardiac tissue. We demonstrate that DNMT3A inactivation augments macrophage-to-cardiac fibroblasts interactions and induces cardiac fibrosis in mice and humans. Mechanistically, DNMT3A inactivation increases the release of heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) to activate cardiac fibroblasts. These findings not only identify a novel pathway of DNMT3A CHIP-driver mutation-induced instigation and progression of HF, but may also provide a rationale for the development of new anti-fibrotic strategies.
Project description:Somatic mutations in DNA Methyltransferase 3A (DNMT3A) with a hotspot in exon 23 at Arginine 882 (DNMT3AR882mut) are the most frequent single mutations in clonal hematopoiesis. Here we analyze the expression of genes and endogenous retrovirus (ERV) sequences in a murine model carrying human DNMT3A-R882H mutation in one allele of the endogenous DNMT3A with respect to normal condition and azacitidine treatment.
Project description:Blood cancers are generally more common in males, and the prevalence of most mutations that drive clonal hematopoiesis and myeloid malignancies is higher in males. In contrast, hematopoietic DNMT3A mutations are more common in females. We sought to investigate if sex hormones might contribute to the female predominance of DNMT3A mutations. We used single-cell RNA- and ATAC-sequencing in murine models to examine genotype-specific sex differences and sex hormone effects on hematopoietic stem and progenitor cells.
Project description:Blood cancers are generally more common in males, and the prevalence of most mutations that drive clonal hematopoiesis and myeloid malignancies is higher in males. In contrast, hematopoietic DNMT3A mutations are more common in females. We sought to investigate if sex hormones might contribute to the female predominance of DNMT3A mutations. We used single-cell RNA- and ATAC-sequencing in murine models to examine genotype-specific sex differences and sex hormone effects on hematopoietic stem and progenitor cells.