Project description:In this study we demonstrate that Tgif1 has a role in HSCs maintenance, self-renewal and quiescence. RNA sequencing data of LSK cells (HSCs enriched cell population) from Tgif1-/- and wild type mice implicates that multiple pathways involved in HSC quiescence and self-renewal are disturbed in Tgif1 deficient mice. RNA expression profiles of wild type (WT) and Tgif1-/- LSK cells were generated by RNA sequencing, in triplicate, using Illumina HiSeq 2000.
Project description:In this study we demonstrate that Tgif1 has a role in HSCs maintenance, self-renewal and quiescence. RNA sequencing data of LSK cells (HSCs enriched cell population) from Tgif1-/- and wild type mice implicates that multiple pathways involved in HSC quiescence and self-renewal are disturbed in Tgif1 deficient mice.
Project description:FoxM1, a mammalian Forkhead Box M1 protein, is known as a typical proliferation-associated transcription factor that regulates of G1/S and G2/M transition in the proliferating cells. However, the in vivo function of FoxM1 in adult stem cells remains unknown. Here, we found that FoxM1 is highly expressed in hematopoietic stem cells (HSCs) and is essential for maintaining quiescence and self-renewal of HSCs in vivo. FoxM1-deficient mice developed leukopenia, thrombocytopenia and neutropenia with an approximately 6-fold decrease in HSC pool size, which is associated with a failure of G0 cell cycle regulation and increased cell cycling in HSCs. FoxM1 absence did not affect lineage commitment of HSCs and progenitors. However, FoxM1 loss significantly reduced the repopulating capacity and self-renewal of long-term HSC in a cell-autonomous manner. Mechanistically, FoxM1 loss markedly down-regulates the expression of orphan nuclear receptor Nurr1, known to regulate HSC quiescence. We found that FoxM1 directly bound the promoter region of Nurr1 and induced transcriptional activity of Nurr1 promoter in vitro, and forced expression of Nurr1 rescued FoxM1-deletion-induced G0 loss of HSC-enriched population in vitro. Thus, our studies show a previously unrecognized role of FoxM1 as a critical regulator of HSC quiescence and self-renewal by controlling Nurr1-mediated pathways. The Hematopoietic Stem Cells (HSCs) were sorted from FoxM1[fl/fl] and Tie2-Cre FoxM1[fl/fl] mice, then amplified with Ovation Pico WTA System V2 before microarray analysis. There are 3 samples from FoxM1[fl/fl]mice and 3 samples from Tie2-Cre FoxM1[fl/fl] mice.
Project description:The fate options of hematopoietic stem cells (HSCs) include self-renewal, differentiation, migration and apoptosis, but the interaction between intracellular Ca2+ and cytoplasmic chaperon protein in regulating fate options of long term-HSCs (LT-HSC) is unknown. We created a S100A6 conditional knockout mouse model in the hematopoietic system and our studies showed that in S100A6KO, the number of LT-HSCs was significantly reduced and HSCs engrafted poorly. After 5FU challenge, the frequency of S100A6KO HSCs remained significantly low. Our data showed that S100A6 failed to self-renew through Akt pathway in an intracellular calcium (Cai2+)-dependent manner. Expression profiling of S100A6KO obtained from gene signatures revealed that cytosolic calcium level and proteins translocation to mitochondria were decreased. Mitochondrial oxidative phosphorylation was impaired in S100A6KO. Proteomic data indicated Hsp90 protein and chaperonin family were reduced. Our findings demonstrated that S100A6 regulates fate options of HSCs self-renewal through integrating Akt signaling, specifically governing mitochondria metabolic function and protein quality.
Project description:Pre-leukemic mutations are thought to promote clonal expansion of hematopoietic stem cells (HSCs) by increasing self-renewal and competitiveness. However, mutations that increase HSC proliferation tend to reduce competitiveness and self-renewal potential, raising the question of how a mutant HSC can sustainably outcompete wild-type HSCs. Activating mutations in NRAS are prevalent in human myeloproliferative disease and leukemia. Here we show that a single allele of oncogenic NrasG12D increases HSC proliferation but also increases reconstituting and self-renewal potential upon serial transplantation in irradiated mice, all without immortalizing HSCs or causing leukemia in our experiments. NrasG12D also confers long-term self-renewal potential upon multipotent progenitors. To explore the mechanism by which NrasG12D promotes HSC proliferation and self-renewal we assessed HSC cell cycle kinetics using H2B-GFP label retention. We found that NrasG12D had a bimodal effect on HSCs, increasing the proliferation of some HSCs while increasing the quiescence and competitiveness of other HSCs. One signal can therefore increase HSC proliferation, competitiveness, and self-renewal through a bimodal effect that promotes proliferation in some HSCs and quiescence in others. 12 RNA samples from mouse bone marrows were analyzed. There are three biological replicates for each subtype.
Project description:Self-renewal is a defining characteristic of stem cells, however the molecular pathways underlying its regulation are poorly understood. Here we demonstrate that conditional inactivation of the Pbx1 proto-oncogene in the hematopoietic compartment results in a progressive loss of long-term hematopoietic stem cells (LT-HSCs) that is associated with concomitant reduction in their quiescence, leading to a defect in the maintenance of self-renewal as assessed by serial transplantation. Transcriptional profiling revealed that multiple stem cell maintenance factors are perturbed in Pbx1-deficient LT-HSCs, which prematurely express a large subset of genes, including cell cycle regulators, normally expressed in non-self-renewing multipotent progenitors. A significant proportion of Pbx1-dependent genes are associated with the Tgf-b pathway, which serves a major role in maintaining HSC quiescence. Pbx1-deficient LT-HSCs are unable to up-regulate the cyclin dependent kinase inhibitor p57 in response to Tgf-b, providing a mechanism through which Pbx1 maintenance of stem cell self-renewal is achieved. Experiment Overall Design: Highly efficient Pbx1 deletion was induced with poly(I:C) in 3 young MxCre+.Pbx1f/f mutant or 2 MxCre-.Pbx1f/f control mice. LT-HSC (Lin-cKit+Sca1+CD34-CD135-) cells were prospectively sorted from bone marrow of individual mice harvested 4 weeks after the last injection of poly(I:C).
Project description:Self-renewal is a defining characteristic of stem cells, however the molecular pathways underlying its regulation are poorly understood. Here we demonstrate that conditional inactivation of the Pbx1 proto-oncogene in the hematopoietic compartment results in a progressive loss of long-term hematopoietic stem cells (LT-HSCs) that is associated with concomitant reduction in their quiescence, leading to a defect in the maintenance of self-renewal as assessed by serial transplantation. Transcriptional profiling revealed that multiple stem cell maintenance factors are perturbed in Pbx1-deficient LT-HSCs, which prematurely express a large subset of genes, including cell cycle regulators, normally expressed in non-self-renewing multipotent progenitors. A significant proportion of Pbx1-dependent genes are associated with the Tgf-b pathway, which serves a major role in maintaining HSC quiescence. Pbx1-deficient LT-HSCs are unable to up-regulate the cyclin dependent kinase inhibitor p57 in response to Tgf-b, providing a mechanism through which Pbx1 maintenance of stem cell self-renewal is achieved. Keywords: genetic modification
Project description:FoxM1, a mammalian Forkhead Box M1 protein, is known as a typical proliferation-associated transcription factor that regulates of G1/S and G2/M transition in the proliferating cells. However, the in vivo function of FoxM1 in adult stem cells remains unknown. Here, we found that FoxM1 is highly expressed in hematopoietic stem cells (HSCs) and is essential for maintaining quiescence and self-renewal of HSCs in vivo. FoxM1-deficient mice developed leukopenia, thrombocytopenia and neutropenia with an approximately 6-fold decrease in HSC pool size, which is associated with a failure of G0 cell cycle regulation and increased cell cycling in HSCs. FoxM1 absence did not affect lineage commitment of HSCs and progenitors. However, FoxM1 loss significantly reduced the repopulating capacity and self-renewal of long-term HSC in a cell-autonomous manner. Mechanistically, FoxM1 loss markedly down-regulates the expression of orphan nuclear receptor Nurr1, known to regulate HSC quiescence. We found that FoxM1 directly bound the promoter region of Nurr1 and induced transcriptional activity of Nurr1 promoter in vitro, and forced expression of Nurr1 rescued FoxM1-deletion-induced G0 loss of HSC-enriched population in vitro. Thus, our studies show a previously unrecognized role of FoxM1 as a critical regulator of HSC quiescence and self-renewal by controlling Nurr1-mediated pathways.
Project description:Self-renewal is a defining characteristic of stem cells, however the molecular pathways underlying its regulation are poorly understood. Here we demonstrate that conditional inactivation of the Pbx1 proto-oncogene in the hematopoietic compartment results in a progressive loss of long-term hematopoietic stem cells (LT-HSCs) that is associated with concomitant reduction in their quiescence, leading to a defect in the maintenance of self-renewal as assessed by serial transplantation. Transcriptional profiling revealed that multiple stem cell maintenance factors are perturbed in Pbx1-deficient LT-HSCs, which prematurely express a large subset of genes, including cell cycle regulators, normally expressed in non-self-renewing multipotent progenitors. Experiment Overall Design: LT-HSC (Lin-cKit+Sca1+CD34-CD135-) and ST-HSC (Lin-cKit+Sca1+CD34+CD135-) cells were prospectively sorted from the BM of MxCre-.Pbx1f/f control mice harvested 4 weeks after the last injection of poly(I:C).
Project description:MTD project_description Inflammation and decreased stem cell function characterize organism aging, yet the relationship between these factors remains incompletely understood. This study shows that aged hematopoietic stem and progenitor cells exhibit increased ground-stage NF-κB activity, which enhances their responsiveness to undergo differentiation and loss of self-renewal in response to inflammation. The study identifies Rad21/cohesin as a critical mediator of NF-κB signals, by increasing chromatin accessibility of inter-/intra-genic and enhancer regions. Rad21/NF-κB are required for normal differentiation, but limit self-renewal of hematopoietic stem cells (HSCs) during aging and inflammation in an NF-κB dependent manner. HSCs from aged mice fail to downregulate Rad21/cohesin and inflammation/differentiation inducing signals in the resolution phase after acute inflammation. and The inhibition of cohesin/NF-κB is sufficient to revert the hypersensitivity of aged HSPCs to inflammation-induced differentiation. During aging, myeloid-biased HSCs with disrupted and naturally occurring reduced expression of Rad21/cohesin are increasingly selected over lymphoid-biased HSCs. Together, Rad21/cohesin mediated NF-κB signaling limits HSPC function during aging and selects for cohesin deficient HSCs with myeloid skewed differentiation.