This SuperSeries is composed of the SubSeries listed below.
Kruppel-like factor 7 overexpression suppresses hematopoietic stem and progenitor cell function.
Specimen part
View SamplesIncreased expression of Kruppel like factor 7 (KLF7) is an independent predictor of poor outcome in pediatric acute lymphoblastic leukemia. The contribution of KLF7 to hematopoiesis has not been previously described. Herein, we characterized the effect on murine hematopoiesis of the loss of KLF7 and enforced expression of KLF7. Long-term multilineage engraftment of Klf7-/- cells was comparable to control cells, and self-renewal, as assessed by serial transplantation, was not affected. Enforced expression of KLF7 results in a marked suppression of myeloid progenitor cell growth and a loss of short- and long-term repopulating activity. Interestingly, enforced expression of KLF7, while resulting in multi-lineage growth suppression that extended to hematopoietic stem cells and common lymphoid progenitors, spared T cells and enhanced the survival of early thymocytes. RNA expression profiling of KLF7-overexpressing hematopoietic progenitors identified several potential target genes mediating these effects. Notably, the known KLF7 target Cdkn1a (p21Cip1/Waf1) was not induced by KLF7, and loss of CDKN1A does not rescue the repopulating defect. These results suggest that KLF7 is not required for normal hematopoietic stem and progenitor (HSPC) function, but increased expression, as seen in a subset of lymphoid leukemia, inhibits myeloid cell proliferation and promotes early thymocyte survival.
Kruppel-like factor 7 overexpression suppresses hematopoietic stem and progenitor cell function.
Specimen part
View SamplesIncreased expression of Kruppel like factor 7 (KLF7) is an independent predictor of poor outcome in pediatric acute lymphoblastic leukemia. The contribution of KLF7 to hematopoiesis has not been previously described. Herein, we characterized the effect on murine hematopoiesis of the loss of KLF7 and enforced expression of KLF7. Long-term multilineage engraftment of Klf7-/- cells was comparable to control cells, and self-renewal, as assessed by serial transplantation, was not affected. Enforced expression of KLF7 results in a marked suppression of myeloid progenitor cell growth and a loss of short- and long-term repopulating activity. Interestingly, enforced expression of KLF7, while resulting in multi-lineage growth suppression that extended to hematopoietic stem cells and common lymphoid progenitors, spared T cells and enhanced the survival of early thymocytes. RNA expression profiling of KLF7-overexpressing hematopoietic progenitors identified several potential target genes mediating these effects. Notably, the known KLF7 target Cdkn1a (p21Cip1/Waf1) was not induced by KLF7, and loss of CDKN1A does not rescue the repopulating defect. These results suggest that KLF7 is not required for normal hematopoietic stem and progenitor (HSPC) function, but increased expression, as seen in a subset of lymphoid leukemia, inhibits myeloid cell proliferation and promotes early thymocyte survival.
Kruppel-like factor 7 overexpression suppresses hematopoietic stem and progenitor cell function.
Specimen part
View SamplesIncreased expression of Kruppel like factor 7 (KLF7) is an independent predictor of poor outcome in pediatric acute lymphoblastic leukemia. The contribution of KLF7 to hematopoiesis has not been previously described. Herein, we characterized the effect on murine hematopoiesis of the loss of KLF7 and enforced expression of KLF7. Long-term multilineage engraftment of Klf7-/- cells was comparable to control cells, and self-renewal, as assessed by serial transplantation, was not affected. Enforced expression of KLF7 results in a marked suppression of myeloid progenitor cell growth and a loss of short- and long-term repopulating activity. Interestingly, enforced expression of KLF7, while resulting in multi-lineage growth suppression that extended to hematopoietic stem cells and common lymphoid progenitors, spared T cells and enhanced the survival of early thymocytes. RNA expression profiling of KLF7-overexpressing hematopoietic progenitors identified several potential target genes mediating these effects. Notably, the known KLF7 target Cdkn1a (p21Cip1/Waf1) was not induced by KLF7, and loss of CDKN1A does not rescue the repopulating defect. These results suggest that KLF7 is not required for normal hematopoietic stem and progenitor (HSPC) function, but increased expression, as seen in a subset of lymphoid leukemia, inhibits myeloid cell proliferation and promotes early thymocyte survival.
Kruppel-like factor 7 overexpression suppresses hematopoietic stem and progenitor cell function.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
G-CSF regulates hematopoietic stem cell activity, in part, through activation of Toll-like receptor signaling.
Specimen part, Treatment
View SamplesRecent studies demonstrate that inflammatory signals regulate hematopoietic stem cells (HSCs). Granulocyte-colony stimulating factor (G-CSF) is often induced with infection and plays a key role in the stress granulopoiesis response. However, its effects on HSCs are less clear. Herein, we show that treatment with G-CSF induces expansion and increased quiescence of phenotypic HSCs, but causes a marked, cell-autonomous HSC repopulating defect associated with induction of toll-like receptor (TLR) expression and signaling. The G-CSF-mediated expansion of HSCs is reduced in mice lacking TLR2, TLR4 or the TLR signaling adaptor MyD88. Induction of HSC quiescence is abrogated in mice lacking MyD88 or in mice treated with antibiotics to suppress intestinal flora. Finally, loss of TLR4 or germ free conditions mitigates the G-CSF-mediated HSC repopulating defect. These data suggest that low level TLR agonist production by commensal flora contributes to the regulation of HSC function and that G-CSF negatively regulates HSCs, in part, by enhancing TLR signaling.
G-CSF regulates hematopoietic stem cell activity, in part, through activation of Toll-like receptor signaling.
Specimen part, Treatment
View SamplesRecent studies demonstratethat inflammatory signals regulate hematopoietic stem cells (HSCs). Granulocyte-colony stimulating factor (G-CSF) is often induced with infection and plays a key role in the stress granulopoiesis response. However, its effects on HSCs are less clear. Herein, we show that treatment with G-CSF induces expansion and increased quiescence of phenotypic HSCs, but causes a marked, cell-autonomous HSC repopulating defect associated with induction of toll-like receptor (TLR) expression and signaling. The G-CSF-mediated expansion of HSCs is reduced in mice lacking TLR2, TLR4 or the TLR signaling adaptor MyD88. Induction of HSC quiescence is abrogated in mice lacking MyD88 or in mice treated with antibiotics to suppress intestinal flora. Finally, loss of TLR4 or germ free conditions mitigates the G-CSF-mediated HSC repopulating defect. These data suggest that low level TLR agonist production by commensal flora contributes to the regulation of HSC function and that G-CSF negatively regulates HSCs, in part, by enhancing TLR signaling.
G-CSF regulates hematopoietic stem cell activity, in part, through activation of Toll-like receptor signaling.
Specimen part, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
New IDH1 mutant inhibitors for treatment of acute myeloid leukemia.
Specimen part
View SamplesNeomorphic mutations in isocitrate dehydrogenase 1 (IDH1) are driver mutations in acute myeloid leukemia (AML) and other cancers. We report the development of new allosteric inhibitors of mutant IDH1. Crystallographic and biochemical results demonstrated that compounds of this chemical series bind to an allosteric site and lock the enzyme in a catalytically inactive conformation, thereby enabling inhibition of different clinically relevant IDH1 mutants. Treatment of IDH1 mutant primary AML cells uniformly led to a decrease in intracellular 2-HG, abrogation of the myeloid differentiation block and induction of granulocytic differentiation at the level of leukemic blasts and more immature stem-like cells, in vitro and in vivo. Molecularly, treatment with the inhibitors led to a reversal of the DNA cytosine hypermethylation patterns caused by mutant IDH1 in AML patients cells. Our study provides proof-of-concept for the molecular and biological activity of novel allosteric inhibitors for targeting different mutant forms of IDH1 in leukemia. To obtain insight into the molecular mechanism for the induction of granulocytic differentiation and cell death following inhibition of IDH1 mutant protein in primary AML cells, we performed gene expression microarrays following treatment with either GSK321 IDH1 inhibitor or Controls (DMSO or GSK990 inactive inhibitor).
New IDH1 mutant inhibitors for treatment of acute myeloid leukemia.
Specimen part
View SamplesGene expression profiling in dopaminergic brain structures of rats self-administering cocaine. Effect of histone deacetylase inhibition
Inhibition of histone deacetylases in rats self-administering cocaine regulates lissencephaly gene-1 and reelin gene expression, as revealed by microarray technique.
Sex, Specimen part, Treatment
View Samples