Megakaryocyte Progenitor Cell Function is Enhanced Upon Aging Despite the Functional Decline of Aged Hematopoietic Stem Cells
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE166704 | GEO | 2021/06/01
REPOSITORIES: GEO
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Project description:Age-related morbidity is associated with a decline in hematopoietic stem cell (HSC) function, but the mechanisms of HSC aging remain unclear. We performed heterochronic HSC transplants followed by quantitative analysis of cell reconstitution. Although young HSCs outperformed old HSCs in young recipients, young HSCs unexpectedly failed to outcompete the old HSCs of aged recipients. Interestingly, despite substantial enrichment of megakaryocyte progenitors (MkPs) in old mice in situ and reported platelet (Plt) priming with age, transplanted old HSCs were deficient in reconstitution of all lineages, including MkPs and Plts. We therefore performed functional analysis of young and old MkPs. Surprisingly, old MkPs displayed unmistakably greater regenerative capacity compared with young MkPs. Transcriptome analysis revealed putative molecular regulators of old MkP expansion. Collectively, these data demonstrated that aging affects HSCs and megakaryopoiesis in fundamentally different ways: whereas old HSCs functionally decline, MkPs gain expansion capacity upon aging.
| S-EPMC8190594 | biostudies-literature
Project description:Megakaryocyte Progenitor Cell Function is Enhanced Upon Aging Despite the Functional Decline of Aged Hematopoietic Stem Cells
| PRJNA701641 | ENA
Project description:Our understanding of cell fate decisions in hematopoietic stem cells is incomplete. Here, we show that the transcription factor Helios is highly expressed in murine hematopoietic stem and progenitor cells (HSPCs), where it is required to suppress the separation of the platelet/megakaryocyte lineage from the HSPC pool. Helios acts mainly in quiescent cells, where it directly represses the megakaryocyte gene expression program in cells as early as the stem cell stage. Helios binding promotes chromatin compaction, notably at the regulatory regions of platelet-specific genes recognized by the Gata2 and Runx1 transcriptional activators, implicated in megakaryocyte priming. Helios null HSPCs are biased toward the megakaryocyte lineage at the expense of the lymphoid and partially resemble cells of aging animals. We propose that Helios acts as a guardian of HSPC pluripotency by continuously repressing the megakaryocyte fate, which in turn allows downstream lymphoid priming to take place. These results highlight the importance of negative and positive priming events in lineage commitment.
| S-EPMC8406645 | biostudies-literature
Project description:Ex vivo production of induced megakaryocytes (MKs) and platelets from stem cells is an alternative approach for supplying transfusible platelets. However, it is still difficult to generate large numbers of MKs and platelets from cord blood hematopoietic stem cells. To optimize the differentiation efficiency of megakaryocytic cells from hematopoietic stem and progenitor cells (HSPCs), we first employed a platelet factor 4 (PF4)-promoter reporter and high-throughput screening strategy to screen for small molecules. We found that a small molecule, Ricolinostat, efficiently promoted the generation of CD34+CD41+ megakaryocyte progenitor cells (MkPs) and CD41+CD61+ MKs from cord blood HSPCs. Ricolinostat showed the capacity to enhance the cell fate commitment of MkPs from HSPCs and promoted the proliferation of CD34+CD41+ MkPs. Ricolinostat significantly increased the gene expression levels of key MK transcriptional factors, including HOXC6 and PCGF2. Notably, these megakaryocytic cells generated from Ricolinostat-induced HSPCs could differentiate into mature MKs and platelets. Additionally, RNA sequencing data suggested that Ricolinostat might enhance MkP fate mainly by inhibiting the secretion of IL-8 and decreasing the expression of IL-8 receptor CXCR2. Our study will help in the development of manufacturing protocols for large-scale generation of induced MKs and platelets for clinical application.
2022-02-09 | GSE182181 | GEO
Project description:Patients with familial platelet disorder with a predisposition to myeloid malignancy (FPDMM) harbor germline monoallelic mutations in a key hematopoietic transcription factor, RUNX-1. Previous studies of FPDMM have focused on megakaryocyte (Mk) differentiation and platelet production and signaling. However, the effects of RUNX-1 haploinsufficiency on hematopoietic progenitor cells (HPCs) and subsequent megakaryopoiesis remains incomplete. We studied induced pluripotent stem cell (iPSC)-derived HPCs (iHPCs) and Mks (iMks) from both patient-derived lines and a wild-type (WT) line modified to be RUNX-1 haploinsufficient (RUNX-1+/-), each compared with their isogenic WT control. All RUNX-1+/- lines showed decreased iMk yield and depletion of an Mk-biased iHPC subpopulation. To investigate global and local gene expression changes underlying this iHPC shift, single-cell RNA sequencing was performed on sorted FPDMM and control iHPCs. We defined several cell subpopulations in the Mk-biased iHPCs. Analyses of gene sets upregulated in FPDMM iHPCs indicated enrichment for response to stress, regulation of signal transduction, and immune signaling-related gene sets. Immunoblot analyses in FPDMM iMks were consistent with these findings, but also identified augmented baseline c-Jun N-terminal kinase (JNK) phosphorylation, known to be activated by transforming growth factor-β1 (TGF-β1) and cellular stressors. These findings were confirmed in adult human CD34+-derived stem and progenitor cells (HSPCs) transduced with lentiviral RUNX1 short hairpin RNA to mimic RUNX-1+/-. In both iHPCs and CD34+-derived HSPCs, targeted inhibitors of JNK and TGF-β1 pathways corrected the megakaryopoietic defect. We propose that such intervention may correct the thrombocytopenia in patients with FPDMM.
| S-EPMC8120143 | biostudies-literature
Project description:BackgroundEx vivo production of induced megakaryocytes (MKs) and platelets from stem cells is an alternative approach for supplying transfusible platelets. However, it is difficult to generate large numbers of MKs and platelets from hematopoietic stem cells and progenitor cells (HSPCs).MethodsTo optimize the differentiation efficiency of megakaryocytic cells from HSPCs, we first employed a platelet factor 4 (PF4)-promoter reporter and high-throughput screening strategy to screen for small molecules. We also investigated the effects and possible mechanisms of candidate small molecules on megakaryocytic differentiation of human HSPCs.ResultsThe small molecule Ricolinostat remarkably promoted the expression of PF4-promoter reporter in the megakaryocytic cell line. Notably, Ricolinostat significantly enhanced the cell fate commitment of MK progenitors (MkPs) from cord blood HSPCs and promoted the proliferation of MkPs based on cell surface marker detection, colony-forming unit-MK assay, and quantitative real-time PCR analyses. MkPs generated from Ricolinostat-induced HSPCs differentiated into mature MKs and platelets. Mechanistically, we found that Ricolinostat enhanced MkP fate mainly by inhibiting the secretion of IL-8 and decreasing the expression of the IL-8 receptor CXCR2.ConclusionThe addition of Ricolinostat to the culture medium promoted MkP differentiation from HSPCs and enhanced the proliferation of MkPs mainly by suppressing the IL-8/CXCR2 pathway. Our results can help the development of manufacturing protocols for the efficient generation of MKs and platelets from stem cells in vitro.
| S-EPMC8817546 | biostudies-literature
Project description:PLZF (promyelocytic leukemia zinc finger) is a transcription factor acting as a global regulator of hematopoietic commitment. PLZF displays an epigenetic specificity by recruiting chromatin-modifying factors but little is known about its role in remodeling chromatin of cells committed toward a given specific hematopoietic lineage. In murine myeloid progenitors, we decipher a new role for PLZF in restraining active genes and enhancers by targeting acetylated lysine 27 of Histone H3 (H3K27ac). Functional analyses reveal that active enhancers bound by PLZF are involved in biological processes related to metabolism and associated with hematopoietic aging. Comparing the epigenome of young and old myeloid progenitors, we reveal that H3K27ac variation at active enhancers is a hallmark of hematopoietic aging. Taken together, these data suggest that PLZF, associated with active enhancers, appears to restrain their activity as an epigenetic gatekeeper of hematopoietic aging.
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Project description:The aged systemic milieu promotes cellular and cognitive impairments in the hippocampus. Here, we report that aging of the hematopoietic system directly contributes to the pro-aging effects of old blood on cognition. Using a heterochronic hematopoietic stem cell (HSC) transplantation model (in which the blood of young mice is reconstituted with old HSCs), we find that exposure to an old hematopoietic system inhibits hippocampal neurogenesis, decreases synaptic marker expression, and impairs cognition. We identify a number of factors elevated in the blood of young mice reconstituted with old HSCs, of which cyclophilin A (CyPA) acts as a pro-aging factor. Increased systemic levels of CyPA impair cognition in young mice, while inhibition of CyPA in aged mice improves cognition. Together, these data identify age-related changes in the hematopoietic system as drivers of hippocampal aging.
| S-EPMC7431826 | biostudies-literature
Project description:Purpose of Review:Functional decline of hematopoiesis that occurs in the elderly, or in patients who receive therapies that trigger cellular senescence effects, results in a progressive reduction in the immune response and an increased incidence of myeloid malignancy. Intracellular signals in hematopoietic stem cells and progenitors (HSC/P) mediate systemic, microenvironment, and cell-intrinsic effector aging signals that induce their decline. This review intends to summarize and critically review our advances in the understanding of the intracellular signaling pathways responsible for HSC decline during aging and opportunities for intervention. Recent Findings:For a long time, aging of HSC has been thought to be an irreversible process imprinted in stem cells due to the cell intrinsic nature of aging. However, recent murine models and human correlative studies provide evidence that aging is associated with molecular signaling pathways, including oxidative stress, metabolic dysfunction, loss of polarity and an altered epigenome. These signaling pathways provide potential targets for prevention or reversal of age-related changes. Summary:Here we review our current understanding of the signalling pathways that are differentially activated or repressed during HSC/P aging, focusing on the oxidative, metabolic, biochemical and structural consequences downstream, and cell-intrinsic, systemic, and environmental influences.
| S-EPMC6709869 | biostudies-literature
Project description:The differentiation of primary human megakaryocyte-erythroid progenitors (MEP) into megakaryocytic (Mk) or erythroid (E) progenitors is critical for maintaining the blood system, yet the mechanisms that regulate this fate specification remain unclear. Here, we analyzed RNA-seq data and found that RUNX1 is a key regulator of differential gene expression in MEP fate specification. Through viral transduction of primary MEP with RUNX1, we demonstrated that overexpression of RUNX1 promotes Mk over E specification, whereas pan-RUNX inhibition promotes E fate specification over Mk. We found that although the levels of total RUNX1 do not differ between MkP and ErP, MkP have higher levels of RUNX1 phosphorylated serine residues, and that serine/threonine phosphorylation of RUNX1 dramatically increases its effectiveness. We used human erythroleukemia (HEL) cell lines with expression of HA-tagged WT RUNX1, phosphomimetic (RUNX1-4D) and non-phosphorylatable (RUNX1-4A) mutants to model their effects on MEP. Although the chromatin association was not informative, the three forms of RUNX1 caused differential expression of 2,625 genes. Approximately 40% of these differentially expressed genes (DEGs) showed an increase with both RUNX1-WT and RUNX1-4D while another 40% showed a decrease with both RUNX1-WT and RUNX1-4D. We compared these DEGs with DEGs from primary human MEP, Mk progenitors (MkP), and E progenitors (ErP), and found that the genes upregulated by WT and RUNX1-4D in HEL cells overlapped significantly with the genes upregulated in MkP vs. MEP, whereas genes downregulated by WT and RUNX1-4D in HEL cells overlapped significantly with the genes downregulated in MkP vs. MEP. These results suggest that phosphorylation of RUNX1 enhances RUNX1’s function to activate or repress transcription of target genes that are up/downregulated during MEP fate specification.
2024-09-24 | GSE232877 | GEO