B cell development requires discrete regulation by PTEN-PI3K and mTOR pathways and the intricate interplay with IL-7 r-Stat5 signaling
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE81844 | GEO | 2018/02/14
REPOSITORIES: GEO
Similar Datasets
Project description:The mechanistic target of rapamycin (mTOR) pathway integrates diverse environmental inputs, including immune signals and metabolic cues, to direct T cell fate decisions1. Activation of mTOR, comprised of mTORC1 and mTORC2 complexes, delivers an obligatory signal for proper activation and differentiation of effector CD4+ T cells2,3, whereas in the regulatory T cell (Treg) compartment, the Akt-mTOR axis is widely acknowledged as a crucial negative regulator of Treg de novo differentiation4-8 and population expansion9. However, whether mTOR signaling affects the homeostasis and function of Tregs remains largely unexplored. Here we show that mTORC1 signaling is a pivotal positive determinant of Treg function. Tregs have elevated steady-state mTORC1 activity compared to naïve T cells. Signals via T cell receptor (TCR) and IL-2 provide major inputs for mTORC1 activation, which in turn programs suppressive function of Tregs. Disruption of mTORC1 through Treg-specific deletion of the essential component Raptor leads to a profound loss of Treg suppressive activity in vivo and development of a fatal early-onset inflammatory disorder. Mechanistically, Raptor/mTORC1 signaling in Tregs promotes cholesterol/lipid metabolism, with the mevalonate pathway particularly important for coordinating Treg proliferation and upregulation of suppressive molecules CTLA-4 and ICOS to establish Treg functional competency. In contrast, mTORC1 does not directly impact the expression of Foxp3 or anti- and pro-inflammatory cytokines in Tregs, suggesting a non-conventional mechanism for Treg functional regulation. Lastly, we provide evidence that mTORC1 maintains Treg function partly through inhibiting the mTORC2 pathway. Our results demonstrate that mTORC1 acts as a fundamental ‘rheostat’ in Tregs to link immunological signals from TCR and IL-2 to lipogenic pathways and functional fitness, and highlight a central role of metabolic programming of Treg suppressive activity in immune homeostasis and tolerance. We used microarrays to explore the gene expression profiles differentially expressed in regulatory T-cells from wild-type and CD4(cre) x Raptor(fl/fl) mice
2013-06-24 | E-GEOD-46693 | biostudies-arrayexpress
Project description:DallePezze2012 - TSC-independent mTORC2
regulation
This model is described in the article:
A dynamic network model of
mTOR signaling reveals TSC-independent mTORC2 regulation.
Dalle Pezze P, Sonntag AG, Thien A,
Prentzell MT, Gödel M, Fischer S, Neumann-Haefelin E, Huber
TB, Baumeister R, Shanley DP, Thedieck K.
Sci Signal 2012 Mar; 5(217): ra25
Abstract:
The kinase mammalian target of rapamycin (mTOR) exists in
two multiprotein complexes (mTORC1 and mTORC2) and is a central
regulator of growth and metabolism. Insulin activation of
mTORC1, mediated by phosphoinositide 3-kinase (PI3K), Akt, and
the inhibitory tuberous sclerosis complex 1/2 (TSC1-TSC2),
initiates a negative feedback loop that ultimately inhibits
PI3K. We present a data-driven dynamic insulin-mTOR network
model that integrates the entire core network and used this
model to investigate the less well understood mechanisms by
which insulin regulates mTORC2. By analyzing the effects of
perturbations targeting several levels within the network in
silico and experimentally, we found that, in contrast to
current hypotheses, the TSC1-TSC2 complex was not a direct or
indirect (acting through the negative feedback loop) regulator
of mTORC2. Although mTORC2 activation required active PI3K,
this was not affected by the negative feedback loop. Therefore,
we propose an mTORC2 activation pathway through a PI3K variant
that is insensitive to the negative feedback loop that
regulates mTORC1. This putative pathway predicts that mTORC2
would be refractory to Akt, which inhibits TSC1-TSC2, and,
indeed, we found that mTORC2 was insensitive to constitutive
Akt activation in several cell types. Our results suggest that
a previously unknown network structure connects mTORC2 to its
upstream cues and clarifies which molecular connectors
contribute to mTORC2 activation.
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2015-08-12 | BIOMD0000000581 | BioModels
Project description:The mechanistic target of rapamycin (mTOR) pathway integrates diverse environmental inputs, including immune signals and metabolic cues, to direct T cell fate decisions1. Activation of mTOR, comprised of mTORC1 and mTORC2 complexes, delivers an obligatory signal for proper activation and differentiation of effector CD4+ T cells2,3, whereas in the regulatory T cell (Treg) compartment, the Akt-mTOR axis is widely acknowledged as a crucial negative regulator of Treg de novo differentiation4-8 and population expansion9. However, whether mTOR signaling affects the homeostasis and function of Tregs remains largely unexplored. Here we show that mTORC1 signaling is a pivotal positive determinant of Treg function. Tregs have elevated steady-state mTORC1 activity compared to naïve T cells. Signals via T cell receptor (TCR) and IL-2 provide major inputs for mTORC1 activation, which in turn programs suppressive function of Tregs. Disruption of mTORC1 through Treg-specific deletion of the essential component Raptor leads to a profound loss of Treg suppressive activity in vivo and development of a fatal early-onset inflammatory disorder. Mechanistically, Raptor/mTORC1 signaling in Tregs promotes cholesterol/lipid metabolism, with the mevalonate pathway particularly important for coordinating Treg proliferation and upregulation of suppressive molecules CTLA-4 and ICOS to establish Treg functional competency. In contrast, mTORC1 does not directly impact the expression of Foxp3 or anti- and pro-inflammatory cytokines in Tregs, suggesting a non-conventional mechanism for Treg functional regulation. Lastly, we provide evidence that mTORC1 maintains Treg function partly through inhibiting the mTORC2 pathway. Our results demonstrate that mTORC1 acts as a fundamental ‘rheostat’ in Tregs to link immunological signals from TCR and IL-2 to lipogenic pathways and functional fitness, and highlight a central role of metabolic programming of Treg suppressive activity in immune homeostasis and tolerance.
2013-06-24 | GSE46693 | GEO
Project description:This model is based on:
Dynamic modeling of signal transduction by mTOR complexes in cancer
Author:
Mohammadreza Dorvash, Mohammad Farahmandnia, Pouria Mosaddeghi, Mitra Farahmandnejad, Hosein Saber, Mohammadhossein Khorraminejad-Shirazi, Amir Azadi, Iman Tavassoly
Abstract:
Signal integration has a crucial role in the cell fate decision and dysregulation of the cellular signaling pathways is a primary characteristic of cancer. As a signal integrator, mTOR shows a complex dynamical behavior which determines the cell fate at different cellular processes levels, including cell cycle progression, cell survival, cell death, metabolic reprogramming, and aging. The dynamics of the complex responses to rapamycin in cancer cells have been attributed to its differential time-dependent inhibitory effects on mTORC1 and mTORC2, the two main complexes of mTOR. Two explanations were previously provided for this phenomenon: 1-Rapamycin does not inhibit mTORC2 directly, whereas it prevents mTORC2 formation by sequestering free mTOR protein (Le Chatelier’s principle). 2-Components like Phosphatidic Acid (PA) further stabilize mTORC2 compared with mTORC1. To understand the mechanism by which rapamycin differentially inhibits the mTOR complexes in the cancer cells, we present a mathematical model of rapamycin mode of action based on the first explanation, i.e., Le Chatelier’s principle. Translating the interactions among components of mTORC1 and mTORC2 into a mathematical model revealed the dynamics of rapamycin action in different doses and time-intervals of rapamycin treatment. This model shows that rapamycin has stronger effects on mTORC1 compared with mTORC2, simply due to its direct interaction with free mTOR and mTORC1, but not mTORC2, without the need to consider other components that might further stabilize mTORC2. Based on our results, even when mTORC2 is less stable compared with mTORC1, it can be less inhibited by rapamycin.
2019-09-30 | BIOMD0000000822 | BioModels
Project description:The mammalian target of rapamycin (mTOR) is a central regulator of cell growth and proliferation in response to growth factor and nutrient signaling. Consequently, this kinase is implicated in metabolic diseases including cancer and diabetes so there is great interest in understanding mTOR regulatory networks. mTOR exists in two functionally distinct complexes, mTORC1 and mTORC2, and whereas the natural product rapamycin only inhibits a subset of mTORC1 functions, recently developed ATP-competitive mTOR inhibitors have revealed new roles for both complexes. To examine the complete spectrum of mTOR responsive cellular processes, we compared the transcriptional profiles of mammalian cells treated with rapamycin versus the ATP-competitive inhibitor PP242. Our analysis provides a genome-wide view of the transcriptional outputs of mTOR signaling that are insensitive to rapamycin. Gene expression in mouse NIH3T3 cells was measured after 18 hour treatment with DMSO (control), 50 nM rapamycin, or 2 uM PP242. Four independent experiments were performed for each condition.
2011-03-15 | E-GEOD-27784 | biostudies-arrayexpress
Project description:AbstractFollicular helper T (Tfh) cells are crucial for germinal center (GC) formation and humoral adaptive immunity. Mechanisms underlying Tfh cell differentiation in peripheral and mucosal lymphoid organs are incompletely understood. We report here that mTOR kinase complexes 1 and 2 (mTORC1 and mTORC2) are essential for Tfh cell differentiation and GC reaction under steady state and after antigen immunization and viral infection. Loss of mTORC1 and mTORC2 in T cells exerted distinct effects on Tfh cell signature gene expression, whereas increased mTOR activity promoted Tfh responses. Deficiency of mTORC2 impaired CD4+ T cell accumulation and IgA production, and aberrantly induced Foxo1 transcription factor. Mechanistically, the costimulatory molecule ICOS activated mTORC1 and mTORC2 to drive glycolysis and lipogenesis, and Glut1-mediated glucose metabolism promoted Tfh cell responses. Altogether, mTOR acts as a central node in Tfh cells to link immune signals to glucose metabolism and transcriptional activity.
2017-08-04 | GSE85555 | GEO
Project description:To comprehensively analyze the effects of mTORC1 inhibition on GSK3, we employed the use of a PI3K/mTOR-specific phospho-antibody microarray that analyzed the site-specific phosphorylation of over 130 kinases within the PI3K/mTOR pathway. The phosphorylation levels of different kinases in monocytes were measured when stimulated with LPS in the presence or absence of a kind of mTORC1 inhibitor, rapamycin More than 130 highly specific and characterized phospho-antibodies for the human mTOR signaling pathway were immobilized and replicated six times on glass slides. The same non-phosphorylated target antibodies were included to allow the determination of the relative level of phosphorylatioin
2010-11-25 | E-GEOD-25520 | biostudies-arrayexpress
Project description:The mechanistic target of rapamycin mTORC1 is a key regulator of cell metabolism and autophagy. Despite widespread clinical use of mTOR inhibitors, the role of mTORC1 in renal tubular function and kidney homeostasis remains elusive. By utilizing constitutive and inducible deletion of conditional Raptor alleles in renal tubular epithelial cells, we discovered that mTORC1 deficiency caused a marked concentrating defect, loss of tubular cells and slowly progressive renal fibrosis. Transcriptional profiling revealed that mTORC1 maintains renal tubular homeostasis by controlling mitochondrial metabolism and biogenesis as well as transcellular transport processes involved in counter-current multiplication and urine concentration. Although mTORC2 partially compensated the loss of mTORC1, exposure to ischemia and reperfusion injury exaggerated the tubular damage in mTORC1-deficient mice, and caused pronounced apoptosis, diminished proliferation rates and delayed recovery. These findings identify mTORC1 as an essential regulator of tubular energy metabolism and as a crucial component of ischemic stress responses. Pharmacological inhibition of mTORC1 likely affects tubular homeostasis, and may be particularly deleterious if the kidney is exposed to acute injury. Furthermore, the combined inhibition of mTORC1 and mTORC2 may increase the susceptibility to renal damage. Raptor fl/fl*KspCre and Raptor fl/fl animals were sacrificed at P14 before the development of an overt functional phenotype. Kidneys were split in half and immediately snap frozen in liquid nitrogen.
2014-06-09 | E-GEOD-54417 | biostudies-arrayexpress
Project description:Interleukin-7 receptor α (encoded by IL7R) is essential for lymphoid development. Whether acute lymphoblastic leukemia (ALL)-related IL7R gain-of-function mutations can trigger leukemogenesis remains unclear. Here, we demonstrate that lymphoid-restricted mutant IL7R, expressed at physiological levels in conditional knock-in mice, establishes a pre-leukemia stage in which B-cell precursors display self-renewal ability, initiating precursor B-ALL that resembles PAX5 P80R or Ph-like human leukemia. Full transformation associates with transcriptional upregulation of oncogenes such as Myc or Bcl2, downregulation of tumor suppressors such as Ikzf1 or Arid2, and major IL-7R signaling upregulation (involving both JAK/STAT5 and PI3K/mTOR), required for leukemia cell viability. Accordingly, maximal signaling drives full penetrance and early leukemia onset in homozygous IL7R mutant animals. Notably, we identify 2 transcriptional subgroups in mouse and human Ph-like ALL, and show that dactolisib and sphingosine-kinase inhibitors are novel treatment avenues for IL-7R-related cases. Our model, a unique resource to explore the pathophysiology and therapeutic vulnerabilities of B-ALL, demonstrates that IL7R can initiate this malignancy.
2021-11-02 | PXD017147 | Pride
Project description:Graft-versus-host-disease (GvHD) is the main complication of allogeneic hematopoietic stem cell transplantation (HSCT). Here we report studies of a patient with chronic GVHD (cGVHD) carrying persistent CD4+ T cell clonal expansion which harbored somatic mTOR, NFKB2, and TLR2 mutations. Functional analysis of the discovered mTOR mutation indicated a gain-of-function alteration and activation of both mTORC1 and mTORC2 signaling pathways leading to increased cell proliferation and decreased apoptosis. Single-cell RNA sequencing and real-time impedance measurements supported increased cytotoxicity of mutated CD4+ T cells. High throughput drug-sensitivity testing suggested mutations induce resistance to mTOR inhibitors but increase sensitivity for HSP90 inhibitors. Our findings suggest that somatic mutations may contribute to aberrant T cell proliferations and participate in the persistent immune activation in cGVHD paving the way for novel targeted therapies.
2020-04-12 | E-MTAB-8911 | biostudies-arrayexpress