Browse
Submit Data
Databases
API
Help

Dataset Information

8 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Evidence for AKT-independent regulation of FOXO1 and FOXO3 in haematopoietic stem and progenitor cells.

ABSTRACT: Transcription factors FOXOs (1, 3, 4) are essential for the maintenance of haematopoietic stem cells. FOXOs are evolutionary conserved substrates of the AKT serine threonine protein kinase that are also phosphorylated by several kinases other than AKT. Specifically, phosphorylation by AKT is known to result in the cytosolic localization of FOXO and subsequent inhibition of FOXO transcriptional activity. In addition to phosphorylation, FOXOs are regulated by a number of other post-translational modifications including acetylation, methylation, redox modulation, and ubiquitination that altogether determine these factors' output. Cumulating evidence raises the possibility that in stem cells, including in haematopoietic stem cells, AKT may not be the dominant regulator of FOXO. To address this question in more detail, we examined gene expression, subcellular localization, and response to AKT inhibition of FOXO1 and FOXO3, the main FOXO expressed in HSPCs (haematopoietic stem and progenitor cells). Here we show that while FOXO1 and FOXO3 transcripts are expressed at similar levels, endogenous FOXO3 protein is mostly nuclear compared to the cytoplasmic localization of FOXO1 in HSPCs. Furthermore, inhibition of AKT does not enhance nuclear localization of FOXO1 nor FOXO3. Nonetheless AKT inhibition in the context of loss of NAD-dependent SIRT1 deacetylase modulates FOXO3 localization in HSPCs. Together, these data suggest that FOXO3 is more active than FOXO1 in primitive haematopoietic stem and multipotent progenitor cells. In addition, they indicate that upstream regulators other than AKT, such as SIRT1, maintain nuclear FOXO localization and activity in HSPCs.

SUBMITTER: Liang R

PROVIDER: S-EPMC4845935 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Regulation of the Flt3 Gene in Haematopoietic Stem and Early Progenitor Cells.

Project description:The MYB transcription factor plays critical roles in normal and malignant haematopoiesis. We previously showed that MYB was a direct activator of FLT3 expression within the context of acute myeloid leukaemia. During normal haematopoiesis, increasing levels of FLT3 expression determine a strict hierarchy within the haematopoietic stem and early progenitor compartment, which associates with lymphoid and myeloid commitment potential. We use the conditional deletion of the Myb gene to investigate the influence of MYB in Flt3 transcriptional regulation within the haematopoietic stem cell (HSC) hierarchy. In accordance with previous report, in vivo deletion of Myb resulted in rapid biased differentiation of HSC with concomitant loss of proliferation capacity. We find that loss of MYB activity also coincided with decreased FLT3 expression. At the chromatin level, the Flt3 promoter is primed in immature HSC, but occupancy of further intronic elements determines expression. Binding to these locations, MYB and C/EBP? need functional cooperation to activate transcription of the locus. This cooperation is cell context dependent and indicates that MYB and C/EBP? activities are inter-dependent in controlling Flt3 expression to influence lineage commitment of multipotential progenitors.

| S-EPMC4575200 | biostudies-literature

Haematopoietic stem and progenitor cells from human pluripotent stem cells.

Project description:A variety of tissue lineages can be differentiated from pluripotent stem cells by mimicking embryonic development through stepwise exposure to morphogens, or by conversion of one differentiated cell type into another by enforced expression of master transcription factors. Here, to yield functional human haematopoietic stem cells, we perform morphogen-directed differentiation of human pluripotent stem cells into haemogenic endothelium followed by screening of 26 candidate haematopoietic stem-cell-specifying transcription factors for their capacity to promote multi-lineage haematopoietic engraftment in mouse hosts. We recover seven transcription factors (ERG, HOXA5, HOXA9, HOXA10, LCOR, RUNX1 and SPI1) that are sufficient to convert haemogenic endothelium into haematopoietic stem and progenitor cells that engraft myeloid, B and T cells in primary and secondary mouse recipients. Our combined approach of morphogen-driven differentiation and transcription-factor-mediated cell fate conversion produces haematopoietic stem and progenitor cells from pluripotent stem cells and holds promise for modelling haematopoietic disease in humanized mice and for therapeutic strategies in genetic blood disorders.

| S-EPMC5872146 | biostudies-literature

Regulation of mammary stem/progenitor cells by PTEN/Akt/beta-catenin signaling.

Project description:Recent evidence suggests that many malignancies, including breast cancer, are driven by a cellular subcomponent that displays stem cell-like properties. The protein phosphatase and tensin homolog (PTEN) is inactivated in a wide range of human cancers, an alteration that is associated with a poor prognosis. Because PTEN has been reported to play a role in the maintenance of embryonic and tissue-specific stem cells, we investigated the role of the PTEN/Akt pathway in the regulation of normal and malignant mammary stem/progenitor cell populations. We demonstrate that activation of this pathway, via PTEN knockdown, enriches for normal and malignant human mammary stem/progenitor cells in vitro and in vivo. Knockdown of PTEN in normal human mammary epithelial cells enriches for the stem/progenitor cell compartment, generating atypical hyperplastic lesions in humanized NOD/SCID mice. Akt-driven stem/progenitor cell enrichment is mediated by activation of the Wnt/beta-catenin pathway through the phosphorylation of GSK3-beta. In contrast to chemotherapy, the Akt inhibitor perifosine is able to target the tumorigenic cell population in breast tumor xenografts. These studies demonstrate an important role for the PTEN/PI3-K/Akt/beta-catenin pathway in the regulation of normal and malignant stem/progenitor cell populations and suggest that agents that inhibit this pathway are able to effectively target tumorigenic breast cancer cells.

| S-EPMC2683567 | biostudies-literature

Live-animal imaging of native haematopoietic stem and progenitor cells.

Project description:The biology of haematopoietic stem cells (HSCs) has predominantly been studied under transplantation conditions1,2. It has been particularly challenging to study dynamic HSC behaviour, given that the visualization of HSCs in the native niche in live animals has not, to our knowledge, been achieved. Here we describe a dual genetic strategy in mice that restricts reporter labelling to a subset of the most quiescent long-term HSCs (LT-HSCs) and that is compatible with current intravital imaging approaches in the calvarial bone marrow3-5. We show that this subset of LT-HSCs resides close to both sinusoidal blood vessels and the endosteal surface. By contrast, multipotent progenitor cells (MPPs) show greater variation in distance from the endosteum and are more likely to be associated with transition zone vessels. LT-HSCs are not found in bone marrow niches with the deepest hypoxia and instead are found in hypoxic environments similar to those of MPPs. In vivo time-lapse imaging revealed that LT-HSCs at steady-state show limited motility. Activated LT-HSCs show heterogeneous responses, with some cells becoming highly motile and a fraction of HSCs expanding clonally within spatially restricted domains. These domains have defined characteristics, as HSC expansion is found almost exclusively in a subset of bone marrow cavities with bone-remodelling activity. By contrast, cavities with low bone-resorbing activity do not harbour expanding HSCs. These findings point to previously unknown heterogeneity within the bone marrow microenvironment, imposed by the stages of bone turnover. Our approach enables the direct visualization of HSC behaviours and dissection of heterogeneity in HSC niches.

| S-EPMC7021587 | biostudies-literature

Tet2 loss leads to hypermutagenicity in haematopoietic stem/progenitor cells.

Project description:TET2 is a dioxygenase that catalyses multiple steps of 5-methylcytosine oxidation. Although TET2 mutations frequently occur in various types of haematological malignancies, the mechanism by which they increase risk for these cancers remains poorly understood. Here we show that Tet2-/- mice develop spontaneous myeloid, T- and B-cell malignancies after long latencies. Exome sequencing of Tet2-/- tumours reveals accumulation of numerous mutations, including Apc, Nf1, Flt3, Cbl, Notch1 and Mll2, which are recurrently deleted/mutated in human haematological malignancies. Single-cell-targeted sequencing of wild-type and premalignant Tet2-/- Lin-c-Kit+ cells shows higher mutation frequencies in Tet2-/- cells. We further show that the increased mutational burden is particularly high at genomic sites that gained 5-hydroxymethylcytosine, where TET2 normally binds. Furthermore, TET2-mutated myeloid malignancy patients have significantly more mutational events than patients with wild-type TET2. Thus, Tet2 loss leads to hypermutagenicity in haematopoietic stem/progenitor cells, suggesting a novel TET2 loss-mediated mechanism of haematological malignancy pathogenesis.

| S-EPMC5414116 | biostudies-literature

Human haematopoietic stem/progenitor cells express several functional sex hormone receptors.

Project description:Evidence has accumulated that murine haematopoietic stem/progenitor cells (HSPCs) share several markers with the germline, a connection supported by recent reports that pituitary and gonadal sex hormones (SexHs) regulate development of murine HSPCs. It has also been reported that human HSPCs, like their murine counterparts, respond to certain SexHs (e.g. androgens). However, to better address the effects of SexHs, particularly pituitary SexHs, on human haematopoiesis, we tested for expression of receptors for pituitary SexHs, including follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prolactin (PRL), as well as the receptors for gonadal SexHs, including progesterone, oestrogens, and androgen, on HSPCs purified from human umbilical cord blood (UCB) and peripheral blood (PB). We then tested the functionality of these receptors in ex vivo signal transduction studies and in vitro clonogenic assays. In parallel, we tested the effect of SexHs on human mesenchymal stromal cells (MSCs). Finally, based on our observation that at least some of the UCB-derived, CD45(-) very small embryonic-like stem cells (VSELs) become specified into CD45(+) HSPCs, we also evaluated the expression of pituitary and gonadal SexH receptors on these cells. We report for the first time that human HSPCs and VSELs, like their murine counterparts, express pituitary and gonadal SexH receptors at the mRNA and protein levels. Most importantly, SexH if added to suboptimal doses of haematopoietic cytokines and growth factors enhance clonogenic growth of human HSPCs as well as directly stimulate proliferation of MSCs.

| S-EPMC4717849 | biostudies-other

Live-animal tracking of individual haematopoietic stem/progenitor cells in their niche.

Project description:Stem cells reside in a specialized, regulatory environment termed the niche that dictates how they generate, maintain and repair tissues. We have previously documented that transplanted haematopoietic stem and progenitor cell populations localize to subdomains of bone-marrow microvessels where the chemokine CXCL12 is particularly abundant. Using a combination of high-resolution confocal microscopy and two-photon video imaging of individual haematopoietic cells in the calvarium bone marrow of living mice over time, we examine the relationship of haematopoietic stem and progenitor cells to blood vessels, osteoblasts and endosteal surface as they home and engraft in irradiated and c-Kit-receptor-deficient recipient mice. Osteoblasts were enmeshed in microvessels and relative positioning of stem/progenitor cells within this complex tissue was nonrandom and dynamic. Both cell autonomous and non-autonomous factors influenced primitive cell localization. Different haematopoietic cell subsets localized to distinct locations according to the stage of differentiation. When physiological challenges drove either engraftment or expansion, bone-marrow stem/progenitor cells assumed positions in close proximity to bone and osteoblasts. Our analysis permits observing in real time, at a single cell level, processes that previously have been studied only by their long-term outcome at the organismal level.

| S-EPMC2820276 | biostudies-literature

FOXO3 induces ubiquitylation of AKT through MUL1 regulation.

Project description:AKT (also known as protein kinase B, PKB) plays an important role in cell survival or tumor progression. For these reasons, AKT is an emerging target for cancer therapeutics. Previously our studies showed that mitochondrial E3 ubiquitin protein ligase 1 (MUL1, also known as MULAN/GIDE/MAPL) is suppressed in head and neck cancer (HNC) and acts as negative regulator against AKT. However, the MUL1 regulatory mechanisms remain largely unknown. Here we report that cisplatin (CDDP) induces thyroid cancer cell death through MUL1-AKT axis. Specifically, CDDP-induced MUL1 leads to ubiquitylation of active form of AKT. We also observed that the role of forkhead box O3 (FOXO3) is pivotal in CDDP-induced MUL1 regulation. FOXO3 knock-downed cells show resistance against CDDP-mediated MUL1-AKT axis. CDDP-mediated intracellular ROS increment plays an important role in FOXO3-MUL1-AKT signal pathway. The data provide compelling evidence to support the idea that the regulation of FOXO3-MUL1-AKT axis can be a novel strategy for the treatment of HNC with CDDP.

| S-EPMC5746397 | biostudies-literature

Xpg limits the expansion of haematopoietic stem and progenitor cells after ionising radiation.

Project description:Reduced capacity of genome maintenance represents a problem for any organism, potentially causing premature death, carcinogenesis, or accelerated ageing. Strikingly though, loss of certain genome stability factors can be beneficial, especially for the maintenance of tissue stem cells of the intestine and the haematopoietic system. We therefore screened for genome stability factors negatively impacting maintenance of haematopoietic stem cells (HSC) in the context of ionising radiation (IR). We found that in vivo knock down of Xeroderma pigmentosum, complementation group G (Xpg) causes elevation of HSC numbers after IR treatment, while numbers of haematopoietic progenitors are elevated to a lesser extent. IR rapidly induces Xpg both on mRNA and on protein level. Prevention of this induction does not influence activation of the checkpoint cascade, yet attenuates late checkpoint steps such as induction of p21 and Noxa. This causes a leaky cell cycle arrest and lower levels of apoptosis, both contributing to increased colony formation and transformation rates. Xpg thus helps to adequately induce DNA damage responses after IR, thereby keeping the expansion of damaged cells under control. This represents a new function of Xpg in the response to IR, in addition to its well-characterized role in nucleotide excision repair.

| S-EPMC5291257 | biostudies-literature

Persistent response of Fanconi anemia haematopoietic stem and progenitor cells to oxidative stress.

Project description:Oxidative stress is considered as an important pathogenic factor in many human diseases including Fanconi anemia (FA), an inherited bone marrow failure syndrome with extremely high risk of leukemic transformation. Members of the FA protein family are involved in DNA damage and other cellular stress responses. Loss of FA proteins renders cells hypersensitive to oxidative stress and cancer transformation. However, how FA cells respond to oxidative DNA damage remains unclear. By using an in vivo stress-response mouse strain expressing the Gadd45β-luciferase transgene, we show here that haematopoietic stem and progenitor cells (HSPCs) from mice deficient for the FA gene Fanca or Fancc persistently responded to oxidative stress. Mechanistically, we demonstrated that accumulation of unrepaired DNA damage, particularly in oxidative damage-sensitive genes, was responsible for the long-lasting response in FA HSPCs. Furthermore, genetic correction of Fanca deficiency almost completely abolished the persistent oxidative stress-induced G2/M arrest and DNA damage response in vivo. Our study suggests that FA pathway is an integral part of a versatile cellular mechanism by which HSPCs respond to oxidative stress.

| S-EPMC5499909 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data