In leukemias and other malignancies of the bone marrow, little is known about the fate of fibroblasts and resident macrophages after normal hematopoietic cells are replaced by neoplastic cells. In the present investigation we used two-stage long-term bone marrow cultures to detect functional stromal cell abnormalities in acute myeloid leukemia, myelodysplastic syndromes and multiple myeloma. While fibroblasts from multiple myeloma and macrophages from multiple myeloma and myelodysplastic syndromes were functionally indistinguishable from the respective cell types from normal bone marrow, fibroblasts from patients with acute myeloid leukemia or myelodysplastic syndromes possessed a significantly lower ability to support hematopoiesis originating from co-cultured normal CD34-positive cells than fibroblasts from healthy marrow. Conversely, macrophages from acute myeloid leukemia marrow significantly enhanced the production of blood cells compared with control macrophages. Aberrant function in fibroblasts and macrophages was associated with consistent changes in the expression of genes whose products are involved in hematopoietic stem cell control, such as cytokines and regulators of the Wnt and Notch signalling pathways.
Functional abnormalities and changes in gene expression in fibroblasts and macrophages from the bone marrow of patients with acute myeloid leukemia.
Sex, Disease, Disease stage, Subject
View SamplesWe used the flu mutant of Arabidopsis to detail gene expression in response to singlet oxygen. The conditional flu mutant of Arabidopsis accumulates excess protochlorophyllide in the dark within chloroplast membranes that upon illumination acts as a photosensitizer and generates singlet oxygen. Immediately after the release of singlet oxygen mature flu plants stop growing, whereas seedlings bleach and die. Within the first 30 min after the release of singlet oxygen rapid changes in nuclear gene expression occur. Distinct sets of genes were activated that were different from those induced by other reactive oxygen species, superoxide or hydrogen peroxide.
Rapid induction of distinct stress responses after the release of singlet oxygen in Arabidopsis.
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View SamplesWe used microarrays to detail Arabidopsis gene expression in response to paraquat, a herbicide that acts as a terminal oxidant of photosystem I that in the light leads to the enhanced generation of superoxide and hydrogen peroxide inside plastids. Within a few hours after paraquat treatment changes in nuclear gene expression occur. Distinct sets of genes were activated that were different from those induced by another reactive oxygen species, singlet oxygen.
Rapid induction of distinct stress responses after the release of singlet oxygen in Arabidopsis.
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