T helper 2 (Th2) cells regulate helminth infections, allergic disorders, tumor immunity, and pregnancy by secreting various cytokines. It is likely that there are undiscovered Th2 signaling ...molecules. Although steroids are known to be immunoregulators, de novo steroid production from immune cells has not been previously characterized. Here, we demonstrate production of the steroid pregnenolone by Th2 cells in vitro and in vivo in a helminth infection model. Single-cell RNA sequencing and quantitative PCR analysis suggest that pregnenolone synthesis in Th2 cells is related to immunosuppression. In support of this, we show that pregnenolone inhibits Th cell proliferation and B cell immunoglobulin class switching. We also show that steroidogenic Th2 cells inhibit Th cell proliferation in a Cyp11a1 enzyme-dependent manner. We propose pregnenolone as a “lymphosteroid,” a steroid produced by lymphocytes. We speculate that this de novo steroid production may be an intrinsic phenomenon of Th2-mediated immune responses to actively restore immune homeostasis.
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•Differential upregulation of the steroid biosynthetic pathway during Th2 differentiation•T helper cells produce the steroid pregnenolone in vitro and in vivo•Steroidogenic Th2 cells suppress Th cell proliferation in a Cyp11a1-dependent manner•Pregnenolone inhibits B cell immunoglobulin class switching in vitro
Immune cells signal by secreting cytokines and by direct cell-to-cell contact. Although steroids are known to be immunoregulators, immune cells are not generally thought to be steroidogenic. Here, Mahata et al. demonstrate that T helper (Th) cells synthesize and secrete the steroid pregnenolone in vitro and in vivo. Pregnenolone inhibits Th cell proliferation and B cell immunoglobulin class switching, and steroidogenic Th cells inhibit Th cell proliferation. This evidence suggests that steroidogenic Th cells contribute to immune homeostasis.
Hematopoietic stem cells (HSCs) cultured outside the body are the fundamental component of a wide range of cellular and gene therapies. Recent efforts have achieved > 200‐fold expansion of functional ...HSCs, but their molecular characterization has not been possible since the majority of cells are non‐HSCs and single cell‐initiated cultures have substantial clone‐to‐clone variability. Using the Fgd5 reporter mouse in combination with the EPCR surface marker, we report exclusive identification of HSCs from non‐HSCs in expansion cultures. By directly linking single‐clone functional transplantation data with single‐clone gene expression profiling, we show that the molecular profile of expanded HSCs is similar to proliferating fetal HSCs and reveals a gene expression signature, including Esam, Prdm16, Fstl1, and Palld, that can identify functional HSCs from multiple cellular states. This “repopulation signature” (RepopSig) also enriches for HSCs in human datasets. Together, these findings demonstrate the power of integrating functional and molecular datasets to better derive meaningful gene signatures and opens the opportunity for a wide range of functional screening and molecular experiments previously not possible due to limited HSC numbers.
Synopsis
This study presents a method for prospectively isolating HSCs from in vitro cultures. Paired molecular and functional analyses on a large number of individual clones identifies a gene expression signature that can identify functional HSCs from multiple cellular states.
EPCR, ESAM and Fgd5 permit prospective identification of functional HSCs from in vitro clones.
Molecular profiling of purified expanded HSCs shows that their profile is similar to proliferating fetal HSCs.
A specific gene signature identifies repopulating HSCs from a wide range of different cellular states, including human HSCs.
This study presents a method for prospectively isolating HSCs from in vitro cultures. Paired molecular and functional analyses on a large number of individual clones identifies a gene expression signature that can identify functional HSCs from multiple cellular states.
Changes in gene regulation and expression govern orderly transitions from hematopoietic stem cells to terminally differentiated blood cell types. These transitions are disrupted during leukemic ...transformation, but knowledge of the gene regulatory changes underpinning this process is elusive. We hypothesized that identifying core gene regulatory networks in healthy hematopoietic and leukemic cells could provide insights into network alterations that perturb cell state transitions. A heptad of transcription factors (LYL1, TAL1, LMO2, FLI1, ERG, GATA2, and RUNX1) bind key hematopoietic genes in human CD34+ hematopoietic stem and progenitor cells (HSPCs) and have prognostic significance in acute myeloid leukemia (AML). These factors also form a densely interconnected circuit by binding combinatorially at their own, and each other's, regulatory elements. However, their mutual regulation during normal hematopoiesis and in AML cells, and how perturbation of their expression levels influences cell fate decisions remains unclear. In this study, we integrated bulk and single-cell data and found that the fully connected heptad circuit identified in healthy HSPCs persists, with only minor alterations in AML, and that chromatin accessibility at key heptad regulatory elements was predictive of cell identity in both healthy progenitors and leukemic cells. The heptad factors GATA2, TAL1, and ERG formed an integrated subcircuit that regulates stem cell-to-erythroid transition in both healthy and leukemic cells. Components of this triad could be manipulated to facilitate erythroid transition providing a proof of concept that such regulatory circuits can be harnessed to promote specific cell-type transitions and overcome dysregulated hematopoiesis.
•Chromatin accessibility patterns at key heptad regulatory elements can predict cell identity in healthy progenitors and leukemic cells.•A subcircuit comprising GATA2, TAL1, and ERG regulates the stem cell to erythroid transition in both healthy and leukemic cells.
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Haematopoietic ageing is marked by a loss of regenerative capacity and skewed differentiation from haematopoietic stem cells (HSCs), leading to impaired blood production. Signals from the bone marrow ...niche tailor blood production, but the contribution of the old niche to haematopoietic ageing remains unclear. Here we characterize the inflammatory milieu that drives both niche and haematopoietic remodelling. We find decreased numbers and functionality of osteoprogenitors at the endosteum and expansion of central marrow LepR
mesenchymal stromal cells associated with deterioration of the sinusoidal vasculature. Together, they create a degraded and inflamed old bone marrow niche. Niche inflammation in turn drives the chronic activation of emergency myelopoiesis pathways in old HSCs and multipotent progenitors, which promotes myeloid differentiation and hinders haematopoietic regeneration. Moreover, we show how production of interleukin-1β (IL-1β) by the damaged endosteum acts in trans to drive the proinflammatory nature of the central marrow, with damaging consequences for the old blood system. Notably, niche deterioration, HSC dysfunction and defective regeneration can all be ameliorated by blocking IL-1 signalling. Our results demonstrate that targeting IL-1 as a key mediator of niche inflammation is a tractable strategy to improve blood production during ageing.
Pancreas development involves a coordinated process in which an early phase of cell segregation is followed by a longer phase of lineage restriction, expansion, and tissue remodeling. By combining ...clonal tracing and whole-mount reconstruction with proliferation kinetics and single-cell transcriptional profiling, we define the functional basis of pancreas morphogenesis. We show that the large-scale organization of mouse pancreas can be traced to the activity of self-renewing precursors positioned at the termini of growing ducts, which act collectively to drive serial rounds of stochastic ductal bifurcation balanced by termination. During this phase of branching morphogenesis, multipotent precursors become progressively fate-restricted, giving rise to self-renewing acinar-committed precursors that are conveyed with growing ducts, as well as ductal progenitors that expand the trailing ducts and give rise to delaminating endocrine cells. These findings define quantitatively how the functional behavior and lineage progression of precursor pools determine the large-scale patterning of pancreatic sub-compartments.
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•The pancreas undergoes rapid cell fate specification in development•Ductal ends serve as a niche site for self-renewing progenitors•These cells drive rounds of stochastic ductal bifurcation balanced by termination•These results provide a model of coordinated development of acini, ducts, and islets
By combining clonal tracing and whole-mount reconstruction with proliferation kinetics and single-cell transcriptional profiling, Sznurkowska et al. show that the large-scale organization of mouse pancreas can be traced to the activity of self-renewing precursors positioned at the termini of growing ducts.
The histone H3 Lys27-specific demethylase UTX (or KDM6A) is targeted by loss-of-function mutations in multiple cancers. Here, we demonstrate that UTX suppresses myeloid leukemogenesis through ...noncatalytic functions, a property shared with its catalytically inactive Y-chromosome paralog, UTY (or KDM6C). In keeping with this, we demonstrate concomitant loss/mutation of KDM6A (UTX) and UTY in multiple human cancers. Mechanistically, global genomic profiling showed only minor changes in H3K27me3 but significant and bidirectional alterations in H3K27ac and chromatin accessibility; a predominant loss of H3K4me1 modifications; alterations in ETS and GATA-factor binding; and altered gene expression after Utx loss. By integrating proteomic and genomic analyses, we link these changes to UTX regulation of ATP-dependent chromatin remodeling, coordination of the COMPASS complex and enhanced pioneering activity of ETS factors during evolution to AML. Collectively, our findings identify a dual role for UTX in suppressing acute myeloid leukemia via repression of oncogenic ETS and upregulation of tumor-suppressive GATA programs.
The murine developing epicardium heterogeneously expresses the transcription factors TCF21 and WT1. Here, we show that this cell heterogeneity is conserved in human epicardium, regulated by BNC1 and ...associated with cell fate and function. Single cell RNA sequencing of epicardium derived from human pluripotent stem cells (hPSC-epi) revealed that distinct epicardial subpopulations are defined by high levels of expression for the transcription factors BNC1 or TCF21. WT1
cells are included in the BNC1
population, which was confirmed in human foetal hearts. THY1 emerged as a membrane marker of the TCF21 population. We show that THY1
cells can differentiate into cardiac fibroblasts (CFs) and smooth muscle cells (SMCs), whereas THY1
cells were predominantly restricted to SMCs. Knocking down BNC1 during the establishment of the epicardial populations resulted in a homogeneous, predominantly TCF21
population. Network inference methods using transcriptomic data from the different cell lineages derived from the hPSC-epi delivered a core transcriptional network organised around WT1, TCF21 and BNC1. This study unveils a list of epicardial regulators and is a step towards engineering subpopulations of epicardial cells with selective biological activities.
Trimethylation of Lys36 in histone H3 (H3K36me3) coordinates events associated with the elongation phase of transcription and is also emerging as an important epigenetic regulator of cell growth and ...differentiation. We have identified the PWWP domain of bromo and plant homeodomain (PHD) finger-containing protein 1 (BRPF1) as a H3K36me3 binding module and have determined the structure of this domain in complex with an H3K36me3-derived peptide.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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