A system of checks and balances: an ERK-dependent feedback mechanism prevents hematopoietic stem cell exhaustion
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA449288 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR6965510.fastq.gz | Fastqsanger.gz | |||
| SRR6965511.fastq.gz | Fastqsanger.gz | |||
| SRR6965512.fastq.gz | Fastqsanger.gz | |||
| SRR6965513.fastq.gz | Fastqsanger.gz | |||
| SRR6965514.fastq.gz | Fastqsanger.gz |
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Project description:Hematopoietic stem cells (HSC) sustain hematopoiesis throughout life, exiting dormancy to replenish homeostatic or acute cell loss in the peripheral blood. HSC activation is supported by PI3-Kinase/AKT/mTORC1 pathway, which promotes mitochondrial expansion, oxidative phosphorylation, and reactive oxygen species production. Activated HSCs must return to dormancy to prevent exhaustion and bone marrow failure, but the cell-intrinsic mechanisms underlying this transition are unknown. Here we identify an ERK-dependent, rate-limiting feedback mechanism that controls the fitness of the HSC compartment. We show that the MEK/ERK and PI3-Kinase pathways are synchronously deployed in HSC during emergency hematopoiesis, and that feedback phosphorylation of MEK1 by activated ERK is required to constrain AKT/mTORC1 activation. Genetic or chemical ablation of this feedback tilts the balance between HSC dormancy and activation, increasing the output of differentiated cells and accelerating HSC exhaustion. MEK inhibitors developed for cancer therapy may thus be useful to modulate HSC activation.
2018-05-28 | GSE112842 | GEO
Project description:Hematopoietic stem cells (HSCs) sustain hematopoiesis throughout life. HSCs exit dormancy to restore hemostasis in response to stressful events, such as acute blood loss, and must return to a quiescent state to prevent their exhaustion and resulting bone marrow failure. HSC activation is driven in part through the phosphatidylinositol 3-kinase (PI3K)/AKT/mTORC1 signaling pathway, but less is known about the cell-intrinsic pathways that control HSC dormancy. Here, we delineate an ERK-dependent, rate-limiting feedback mechanism that controls HSC fitness and their re-entry into quiescence. We show that the MEK/ERK and PI3K pathways are synchronously activated in HSCs during emergency hematopoiesis and that feedback phosphorylation of MEK1 by activated ERK counterbalances AKT/mTORC1 activation. Genetic or chemical ablation of this feedback loop tilts the balance between HSC dormancy and activation, increasing differentiated cell output and accelerating HSC exhaustion. These results suggest that MEK inhibitors developed for cancer therapy may find additional utility in controlling HSC activation.
| S-EPMC5988582 | biostudies-literature
Project description:About 50% of human malignancies exhibit unregulated signalling through the Ras-ERK1/2 (ERK) pathway, as a consequence of activating mutations in members of Ras and Raf families. However, the quest for alternative Ras-ERK pathway-directed therapies is desirable. Upon phosphorylation ERK dimerize. We had previously demonstrated that dimerization is essential for ERK extranuclear but not nuclear signaling. Furthermore, by molecular biology approaches, we showed that specifically inhibiting ERK extranuclear component, by impeding ERK dimerization, is sufficient for curtailing tumor progression. Here, we have identified a small molecule inhibitor for ERK dimerization in vitro and in vivo that, without affecting ERK phosphorylation, prevents tumorigenesis driven by Ras-ERK pathway oncogenes, both in cellular and animal models. Importantly, this compound is unaffected by resistance-acquisition processes that hamper “classical” Ras-ERK pathway inhibitors. Thus, ERK dimerization inhibitors provide the proof of principle for two novel concepts in cancer therapy: 1) The blockade of sublocalization-specific sub-signals, rather than total signals, as a means of effectively counteracting oncogenic Ras-ERK signaling. 2) Targeting regulatory protein-protein interactions such as dimerization, rather than catalytic activities, within a signaling route, as an approach for producing effective anti-tumoral agents. Strategies aimed at preventing aberrant flux through this route remain an attractive option for therapeutic intervention in cancer. In this respect, drugs inhibiting the kinase activities of BRaf and MEK have yielded promising results. A375p cells treated with10 μM of either DEL22379, SCH772984 or DMSO as a control for two hours. mRNA from A375p cells was extrated using RNeasy mini kit (Qiagen, Germany) according to the manufacturer's instructions. Cells were previously treated with10 μM of either DEL22379, SCH772984 or DMSO as a control for two hours.
2015-04-24 | E-GEOD-68230 | biostudies-arrayexpress
Project description:About 50% of human malignancies exhibit unregulated signalling through the Ras-ERK1/2 (ERK) pathway, as a consequence of activating mutations in members of Ras and Raf families. However, the quest for alternative Ras-ERK pathway-directed therapies is desirable. Upon phosphorylation ERK dimerize. We had previously demonstrated that dimerization is essential for ERK extranuclear but not nuclear signaling. Furthermore, by molecular biology approaches, we showed that specifically inhibiting ERK extranuclear component, by impeding ERK dimerization, is sufficient for curtailing tumor progression. Here, we have identified a small molecule inhibitor for ERK dimerization in vitro and in vivo that, without affecting ERK phosphorylation, prevents tumorigenesis driven by Ras-ERK pathway oncogenes, both in cellular and animal models. Importantly, this compound is unaffected by resistance-acquisition processes that hamper “classical” Ras-ERK pathway inhibitors. Thus, ERK dimerization inhibitors provide the proof of principle for two novel concepts in cancer therapy: 1) The blockade of sublocalization-specific sub-signals, rather than total signals, as a means of effectively counteracting oncogenic Ras-ERK signaling. 2) Targeting regulatory protein-protein interactions such as dimerization, rather than catalytic activities, within a signaling route, as an approach for producing effective anti-tumoral agents. Strategies aimed at preventing aberrant flux through this route remain an attractive option for therapeutic intervention in cancer. In this respect, drugs inhibiting the kinase activities of BRaf and MEK have yielded promising results.
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Project description:LKB1 prevents ILC2 exhaustion and lung cancer metastasis
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Project description:Neurofibromatosis Type 1 (NF1) patients develop benign neurofibromas and malignant peripheral nerve sheath tumors (MPNST). These incurable peripheral nerve tumors result from loss of NF1 tumor suppressor gene function, causing hyperactive Ras signaling. Activated Ras controls numerous downstream effectors, but specific pathways mediating effects of hyperactive Ras in NF1 tumors are unknown. Cross-species transcriptome analyses of mouse and human neurofibromas and MPNSTs identified global negative feedback of genes that regulate Ras-Raf- MEK- extracellular signal-regulated protein kinase (ERK) signaling in both species. Nonetheless, activation of ERK was sustained in mouse and human neurofibromas and MPNST. PD0325901, a highly selective pharmacological inhibitor of MEK, was used to test whether sustained Ras-Raf-MEK-ERK signaling contributes to neurofibroma growth in the Nf1fl/fl;Dhh-cre mouse model or in NF1 patient MPNST cell xenografts. PD0325901 treatment reduced aberrantly proliferating cells in neurofibroma and MPNST, prolonged survival of mice implanted with human MPNST cells, and shrank neurofibromas in >80% of mice tested. PD0325901 also caused effects on tumor vasculature. Our data demonstrate that deregulated Ras/ERK signaling is critical for the growth of NF1 peripheral nerve tumors and provide strong rationale for testing MEK inhibitors in NF1 clinical trials.
2012-12-28 | GSE41747 | GEO
Project description:Neurofibromatosis Type 1 (NF1) patients develop benign neurofibromas and malignant peripheral nerve sheath tumors (MPNST). These incurable peripheral nerve tumors result from loss of NF1 tumor suppressor gene function, causing hyperactive Ras signaling. Activated Ras controls numerous downstream effectors, but specific pathways mediating effects of hyperactive Ras in NF1 tumors are unknown. Cross-species transcriptome analyses of mouse and human neurofibromas and MPNSTs identified global negative feedback of genes that regulate Ras-Raf- MEK- extracellular signal-regulated protein kinase (ERK) signaling in both species. Nonetheless, activation of ERK was sustained in mouse and human neurofibromas and MPNST. PD0325901, a highly selective pharmacological inhibitor of MEK, was used to test whether sustained Ras-Raf-MEK-ERK signaling contributes to neurofibroma growth in the Nf1fl/fl;Dhh-cre mouse model or in NF1 patient MPNST cell xenografts. PD0325901 treatment reduced aberrantly proliferating cells in neurofibroma and MPNST, prolonged survival of mice implanted with human MPNST cells, and shrank neurofibromas in >80% of mice tested. PD0325901 also caused effects on tumor vasculature. Our data demonstrate that deregulated Ras/ERK signaling is critical for the growth of NF1 peripheral nerve tumors and provide strong rationale for testing MEK inhibitors in NF1 clinical trials. 83 microarrays: Mouse control (15), Mouse neurofibroma (15), Mouse MPNST (18); Human nerve (3), Human neurofibroma (26), Human MPNST (6) We used the same human tumor samples as in series GSE14038 (dNF, pNF and MPNST). However, instead of referencing gene expression changes to the normal human Schwann cell samples (NHSC) as we did in series GSE14038, we generated three (new) normal nerve samples (samples jan-N1-3) and referenced gene expression changes to those samples. Moreover, the analysis of series GSE14038 evaluated changes in expression between NHSC, benign tumor subtypes (dNF and pNF), and malignant tumors (MPNST), while our present submission evaluated changes between normal nerve, benign tumors (combined dNF and pNF),and malignant tumors (MPNST). The Series supplementary 'merged_data.txt' file contains the data for 9,891 transcripts that were statistically different in at least one of the two species and present in both mouse and human data sets.
2012-12-28 | E-GEOD-41747 | biostudies-arrayexpress
Project description:Epigenetic regulation drives the differentiation of T cells into phenotypically stable subsets including a dysfunctional state termed exhaustion, the presence of these epigenetically distinct T cells in tumors make them non-responsive to checkpoint blockade. Cancer immunotherapies restoring T cell function have transformed cancer treatment by preventing immune evasion of tumor cells allowed by T cell exhaustion. However, some patients develop resistance to immunotherapy or do not respond. Recent literature has demonstrated that epigenetic regulation governs the transition from effector to exhausted T cells. Here, we describe a novel antigen-specific assay for T-cell exhaustion that produces T cells biologically and epigenetically similar to their in vivo exhausted counterpart. We perform a CRISPR KO screen for epigenetic regulators of the human genome and validate Ikaros as a driver of T-cell exhaustion. We determined that the Ikaros degrader iberdomide prevents exhaustion by blocking chromatin remodeling at T cell effector enhancers by preserving activity of key transcription factors AP-1, NF-κB and NFAT using transcription factor footprinting analysis. Thus, our study uncovers a role for Ikaros, degraded by the drug iberdomide, as a driver of T-cell exhaustion.
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Project description:Epigenetic regulation drives the differentiation of T cells into phenotypically stable subsets including a dysfunctional state termed exhaustion, the presence of these epigenetically distinct T cells in tumors make them non-responsive to checkpoint blockade. Cancer immunotherapies restoring T cell function have transformed cancer treatment by preventing immune evasion of tumor cells allowed by T cell exhaustion. However, some patients develop resistance to immunotherapy or do not respond. Recent literature has demonstrated that epigenetic regulation governs the transition from effector to exhausted T cells. Here, we describe a novel antigen-specific assay for T-cell exhaustion that produces T cells biologically and epigenetically similar to their in vivo exhausted counterpart. We perform a CRISPR KO screen for epigenetic regulators of the human genome and validate Ikaros as a driver of T-cell exhaustion. We determined that the Ikaros degrader iberdomide prevents exhaustion by blocking chromatin remodeling at T cell effector enhancers by preserving activity of key transcription factors AP-1, NF-κB and NFAT using transcription factor footprinting analysis. Thus, our study uncovers a role for Ikaros, degraded by the drug iberdomide, as a driver of T-cell exhaustion.
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2024-10-04 | GSE273721 | GEO