Project description:Analysis of gene-expression alterations in primitive LT-HSCs as early as 2 days post sex steroid ablation. This study aimed to determine potential intrinsic changes occuring in the LT-HSC population associated with sex steroid ablation (SSA) at a timepoint that preceeded the earliest reported functional hematopoietic enhancements occuring at day 7 post SSA. These results are vital in providing insight into the role of LT-HSCs in initiating SSA-mediated immune regeneration. Total RNA obtained from BM-sorted LT-HSC 2 days after sex steroid ablation compared to sham sex steroid ablation controls.
Project description:Analysis of gene-expression alterations in primitive LT-HSCs as early as 2 days post sex steroid ablation. This study aimed to determine potential intrinsic changes occuring in the LT-HSC population associated with sex steroid ablation (SSA) at a timepoint that preceeded the earliest reported functional hematopoietic enhancements occuring at day 7 post SSA. These results are vital in providing insight into the role of LT-HSCs in initiating SSA-mediated immune regeneration.
Project description:In the field, adult male rodents are more frequently infected with hantaviruses than females. Early data suggests that sex steroid hormones modulate sex differences in host immune response. This project focuses on elucidating sex differences in gene expression in the lungs of infected males 15 and 40 days post infection with Seoul virus (naturally occurring hantavirus in Norway rats) relative to infected females 15 and 40 days post infection on 12 RG_U34 GeneChips. Keywords: other
Project description:Long-term hematopoietic stem cells (LT-HSCs) reside in bone marrow (BM) niches with low levels of oxygen and reactive oxygen species (ROS). ROS enhancement results in differentiation of LT-HSCs. Redox disturbances are involved in BM failure and leukemia. Paraoxonase-2 (PON2) has been shown to be important for ROS control. However, the role of PON2 in the hematopoietic system has not been addressed. Analysis of young mice with inactivated Pon2 gene (Pon2-/- mice; 3 months) revealed changes in quantity of hematopoietic stem and progenitor cells (HSPCs), which indicate changes in cell differentiation. Experiments with aged PON2-/- mice (>9 months) showed alterations of the HSPC compartment indicating changed self-renewal ability of HSCs and myeloid skewing. Reciprocal BM transplantation reveals cell intrinsic as well as extrinsic phenotypes. We observed markedly enhanced superoxide levels in BM as well as slightly enhanced total ROS level in short term (ST)-HSCs and multipotent progenitor cells (MPPs) of young mice. In aged mice, total ROS level was slightly increased in all 3 fractions of the Lin-, Sca1+, ckit+ (LSK) population. No changes in the amount of DNA double-strand breaks in LSK cells and decreased apoptosis rates in LT-HSCs of young as well as LT- and ST-HSCs of aged PON2-/- mice were seen, indicating a strong compensation mechanism. Changes of gene expression in PON2-/- LT-HSCs identified by RNA sequencing strengthened our conclusions. Additionally, competitive and serial bone marrow transplantation experiments exposed advantages of PON2-/- BMCs in multi-lineage reconstitution. Collectively, these analyses propose PON2 as crucial redox control enzyme in HSCs.
Project description:The vulnerability of bone marrow hematopoiesis to perturbations of cholesterol metabolism is well documented, while the underlying cellular and molecular mechanisms remain poorly understood. Here we reveal a distinct cholesterol metabolic signature of hematopoietic stem cells (HSCs) within the hematopoietic compartment.To identify the phenotype switching and function variation in BM LT-HSCs with HCD treatment, we performed RNA-seq of LT-HSCs from the bone marrow of mice with or without3-month HCD treatment.
Project description:The vulnerability of bone marrow hematopoiesis to perturbations of serine metabolism as well as the underlying cellular and molecular mechanisms remain poorly understood. Here we reveal a distinct serine metabolic signature of hematopoietic stem cells (HSCs) within the hematopoietic compartment.To identify the phenotype switching and function variation in BM LT-HSCs with SGFD treatment, we performed RNA-seq of LT-HSCs from the bone marrow of mice with or without3-month SGFD treatment.
Project description:In the field, adult male rodents are more frequently infected with hantaviruses than females. Early data suggests that sex steroid hormones modulate sex differences in host immune response. This project focuses on elucidating sex differences in gene expression in the lungs of infected males 15 and 40 days post infection with Seoul virus (naturally occurring hantavirus in Norway rats) relative to infected females 15 and 40 days post infection on 12 RG_U34 GeneChips.
Project description:Long-term hematopoietic stem cells (LT-HSCs) are responsible for lifelong maintenance and regeneration of the blood system. Loss of LT-HSC function is a major contributor to decline in hematopoietic function with aging, leading to increased rate of infection, poor vaccination response, and increased risk of hematologic malignancies. While cellular and molecular hallmarks of LT-HSC aging have been defined1-3, a barrier to achieving the goal of extending healthy hematopoietic function into older age is the lack of understanding of the nature and timing of the initiating events that cause LT-HSC aging. Here we show that hallmarks of LT-HSC aging and decline in hematopoietic function accumulate by middle age in mice, and that the hematopoietic cell-extrinsic bone marrow (BM) microenvironment at middle age is necessary and sufficient to cause LT-HSC aging. Using unbiased transcriptome-based approaches, we identify decreased production of IGF1 by mesenchymal stromal cells (MSC) in the local middle-aged BM microenvironment as a factor causing LT-HSC aging and show that direct stimulation of middle-aged LT-HSCs with IGF1 rescues hallmarks of aging. Together, our study demonstrates that the initiating events causing LT-HSC and hematopoietic aging emerge by middle age and are caused by hematopoietic cell-extrinsic changes in the BM microenvironment. Declining IGF1 in the BM microenvironment at middle age represents a compelling target for intervention using prophylactic therapies to effectively extend healthspan and prevent decline in hematopoietic function during aging.
Project description:Long-term hematopoietic stem cells (LT-HSCs) are responsible for lifelong maintenance and regeneration of the blood system. Loss of LT-HSC function is a major contributor to decline in hematopoietic function with aging, leading to increased rate of infection, poor vaccination response, and increased risk of hematologic malignancies. While cellular and molecular hallmarks of LT-HSC aging have been defined1-3, a barrier to achieving the goal of extending healthy hematopoietic function into older age is the lack of understanding of the nature and timing of the initiating events that cause LT-HSC aging. Here we show that hallmarks of LT-HSC aging and decline in hematopoietic function accumulate by middle age in mice, and that the hematopoietic cell-extrinsic bone marrow (BM) microenvironment at middle age is necessary and sufficient to cause LT-HSC aging. Using unbiased transcriptome-based approaches, we identify decreased production of IGF1 by mesenchymal stromal cells (MSC) in the local middle-aged BM microenvironment as a factor causing LT-HSC aging and show that direct stimulation of middle-aged LT-HSCs with IGF1 rescues hallmarks of aging. Together, our study demonstrates that the initiating events causing LT-HSC and hematopoietic aging emerge by middle age and are caused by hematopoietic cell-extrinsic changes in the BM microenvironment. Declining IGF1 in the BM microenvironment at middle age represents a compelling target for intervention using prophylactic therapies to effectively extend healthspan and prevent decline in hematopoietic function during aging.
Project description:Long-term hematopoietic stem cells (LT-HSCs) are responsible for lifelong maintenance and regeneration of the blood system. Loss of LT-HSC function is a major contributor to decline in hematopoietic function with aging, leading to increased rate of infection, poor vaccination response, and increased risk of hematologic malignancies. While cellular and molecular hallmarks of LT-HSC aging have been defined1-3, a barrier to achieving the goal of extending healthy hematopoietic function into older age is the lack of understanding of the nature and timing of the initiating events that cause LT-HSC aging. Here we show that hallmarks of LT-HSC aging and decline in hematopoietic function accumulate by middle age in mice, and that the hematopoietic cell-extrinsic bone marrow (BM) microenvironment at middle age is necessary and sufficient to cause LT-HSC aging. Using unbiased transcriptome-based approaches, we identify decreased production of IGF1 by mesenchymal stromal cells (MSC) in the local middle-aged BM microenvironment as a factor causing LT-HSC aging and show that direct stimulation of middle-aged LT-HSCs with IGF1 rescues hallmarks of aging. Together, our study demonstrates that the initiating events causing LT-HSC and hematopoietic aging emerge by middle age and are caused by hematopoietic cell-extrinsic changes in the BM microenvironment. Declining IGF1 in the BM microenvironment at middle age represents a compelling target for intervention using prophylactic therapies to effectively extend healthspan and prevent decline in hematopoietic function during aging.