ATF4-SLC7A11-GSH axis mediates the acquisition of immunosuppressive properties by activated CD4+ T cells in low arginine condition
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ABSTRACT:
PROVIDER: PRJNA1078370 | ENA |
REPOSITORIES: ENA
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Project description:The tumor microenvironment (TME) is restricted in metabolic nutrients including the semi-essential amino acid arginine. While complete arginine deprivation causes T cell dysfunction, it remains unclear how arginine levels fluctuate in the TME to shape T cell fates. Here, we found that the 20μM low arginine condition, as present in multiple TMEs, confers upon activated T cells Treg-like immunosuppressive capacities. In vivo mouse tumor models and human scRNA-Seq datasets reveal positive correlations between low arginine condition and intratumoral Treg accumulation. Mechanistically, low-arginine activated T cells engage in metabolic and transcriptional reprogramming, using the ATF4-SLC7A11-GSH axis, to preserve their suppressive function. These findings improve our understanding of the role of arginine in human T cell biology with potential applications for immunotherapy strategies.
2024-02-25 | GSE256171 | GEO
Project description:Pien-Tze-Huang Promotes Hepatocellular Carcinoma Cell Ferroptosis by Inhibiting SLC7A11-GSH-GPX4 Axis
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Project description:ATF4 suppresses hepatocarcinogenesis by inducing SLC7A11 (xCT) to suppress stress-related ferroptosis
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Project description:In response to a variety of upstream growth and oncogenic signals, the mechanistic target of rapamycin complex 1 (mTORC1) promotes anabolic metabolism, in part, through activation of downstream transcription factors. The transcription factor activating transcription factor 4 (ATF4) has been previously shown to function downstream of mTORC1 signaling to promote de novo purine synthesis and this activation of ATF4 can occur independently of the canonical activation of ATF4 through the integrated stress response (ISR). Here, we show that ATF4 activation through mTORC1 signaling drives a specific transcriptional program through ATF4 which is comprised of only a subset of genes involved in the broader cellular stress response. We find genes involved in amino acid uptake, biosynthesis, and charging by tRNA synthetases display transcriptional changes downstream of both mTORC1 and ATF4. We discovered that ATF4 activation contributes to the mTORC1-stimulated increase in protein synthesis, highlighting the importance of these transcriptional changes. Additionally, we observe regulation of the cystine transporter SLC7A11 by ATF4. We show that SLC7A11 is important for cell survival and is one mechanism by which cells with active mTORC1 signaling produce glutathione. Thus, ATF4 downstream of mTORC1 signaling regulates protein and glutathione synthesis.
2020-09-28 | GSE158605 | GEO
Project description:Background: Autologous fat grafting is hampered by unpredictable graft survival, which is potentially regulated by ferroptosis. Glutathione (GSH), a powerful antioxidant used in tissue preservation, has ferroptosis-regulating activity; however, its effects on fat grafts are unclear. This study investigated the effects and mechanisms of GSH in fat graft survival. Methods: Human lipoaspirates were transplanted subcutaneously into the backs of normal saline-treated (control) or GSH-treated nude mice. Graft survival was evaluated by magnetic resonance imaging and histology. RNA sequencing was performed to identify differentially expressed genes and enriched pathways. GSH activity was evaluated in vitro using an oxygen and glucose deprivation (OGD) model of adipose-derived stem cells. Results: Compared with control group, GSH induced better outcomes, including superior graft retention, appearance, and histological structures. RNA sequencing suggested enhanced negative regulation of ferroptosis in the GSH-treated grafts, which showed reduced lipid peroxides, better mitochondrial ultrastructure, and SLC7A11/GPX4 axis activation. In vitro, OGD-induced ferroptosis was ameliorated by GSH, which restored cell proliferation, reduced oxidative stress, and upregulated ferroptosis defense factors. Conclusions: Our study confirms that ferroptosis participates in regulating fat graft survival and that GSH exerts a protective effect by inhibiting ferroptosis. GSH-assisted lipotransfer is a promising therapeutic strategy for future clinical application.
2023-05-08 | GSE231511 | GEO
Project description:The goal of this study is to provide the liver metabolic changes in the liver specific Atf4 knockout MUP-uPA (MUP-uPA/Atf4Δhep) mice and understand the function of ATF4 in the stressed liver
2023-12-09 | GSE191115 | GEO
Project description:Background: Arginine deprivation was shown previously to inhibit retinoblastoma cell proliferation and induce cell death in vitro. However, the mechanisms by which retinoblastoma cells respond to arginine deprivation remain to be elucidated. Methods: Human derived retinoblastoma cell lines Y79 and WERI-Rb-1 were exposed to arginine depletion, and the effects on inhibiting cell growth and survival were evaluated. The study investigated potential mechanisms, including autophagy, cell cycle arrest, and apoptosis. Moreover, the roles of GCN2 and mTOR signaling pathways in these processes were examined. Results: We demonstrated that arginine deprivation effectively inhibited the growth of retinoblastoma cells in vitro. This treatment caused an increase in autophagic response. Additionally, we found that prolonged arginine shortage induced G2 cell cycle arrest and was accompanied by an increase in early apoptotic cells. Importantly, arginine depletion also caused an activation of GCN2 and an inhibition of mTOR signaling. We also discovered that the activation of SLC7A11 was regulated by GCN2 upon arginine deprivation. Knockdown of SLC7A11 rendered retinoblastoma cells partially resistant to arginine deprivation. Furthermore, we found that knockdown of GCN2 led to a decrease in autophagic response in WERI-Rb-1 cells and arrested more cells in S phase, which was accompanied by fewer apoptotic cells. Moreover, knockdown of GCN2 caused constant expression of ATF4, phosphorylation of 70S6K, and 4E-BP1 regardless of arginine deprivation. Conclusions: Collectively, our findings suggest that the GCN2-SLC7A11 axis regulates cell growth and survival upon arginine deprivation through coordinating autophagy, cell cycle arrest, and apoptosis in retinoblastoma cells. This work paves the way for the development of a novel treatment for retinoblastoma.
2024-10-28 | GSE278276 | GEO
Project description:Long intergenic non-coding RNA 894 (LINC00894) modulates cancer cell proliferation and drug resistance in several tissue types. However, its role in brain is still unclear. Using RNA-pull down combined with mass spectrometry and RNA binding protein immunoprecipitation, EIF5 was identified to physically interact with LINC00894. Furthermore, LINC00894 knockdown decreased EIF5 protein expression, whereas LINC00894 overexpression increased EIF5 protein expression in cultured cells. Additionally, LINC00894 affected the ubiquitination modification of EIF5. Adeno-associated virus (AAV) mediated LINC00894 overexpression in the brains of transient middle cerebral artery occlusion reperfusion (MCAO/R) mice and rats and inhibited the expression of activated caspase-3. Meanwhile, LINC00894 knockdown increased in the oxygen–glucose deprivation and reoxygenation (OGD/R) in vitro models, whereas its overexpression decreased apoptotic cells and expression of activated caspase-3. Further, LINC00894 overexpression was revealed to increase, whereas its knockdown shortened ATF4 protein half-life. LINC00894 knockdown also decreased the expression of glutamate-cysteine ligase catalytic subunit (GCLC) and ATF4, downregulated glutathione (GSH), and the ratio of GSH to oxidized GSH (GSH: GSSG) in vitro. RNA-seq analysis combined with qRT-PCR and immunoblot showed overexpression of LINC0084 upregulated ATF4, thereby potentially targeting fibroblast growth factor 21 (FGF21) and aconitate decarboxylase 1 (ACOD1) in the MCAO/R model. Finally, we revealed that ATF4 regulated FGF21 and ACOD1 expression by directly binding to promoters; and ectopic overexpression of FGF21 or ACOD1 in LINC00894 knockdown cells decreased activated caspase-3 expression in the OGD/R model. Our results indicated that LINC00894 regulated cerebral ischemia injury by stabilizing EIF5 and facilitating EIF5-ATF4-dependent induction of FGF21 and ACOD1
2024-06-06 | GSE268399 | GEO
Project description:The essential thiol antioxidant, glutathione (GSH) is recruited into the nucleus of mammalian cells early in cell proliferation, suggesting a key role of the nuclear thiol pool in cell cycle regulation. However, the functions of nuclear GSH (GSHn) and its integration with the cytoplasmic GSH (GSHc) pools in whole cell redox homeostasis and signaling are unknown. Here we show that GSH is recruited into the nucleus early in cell proliferation in Arabidopsis thaliana, confirming the requirement for localization of GSH in the nucleus as a universal feature of cell cycle regulation. GSH accumulation in the nucleus was triggered by treatments that synchronize cells at G1/S as identified by flow cytometry and marker transcripts. Significant decreases in transcripts associated with oxidative signaling and stress tolerance occurred when GSH was localized in the nucleus. Increases in GSH1 and GSH2 transcripts accompanied the large increase in total cellular GSH observed during cell proliferation, but only GSH2 was differentially expressed in cells with high GSHn relative to those with an even intracellular distribution of GSH. Of the 7 Bcl-2 associated (BAG) genes in A. thaliana, only the nuclear-localized BAG 6 was differentially expressed in cells with high GSHn compared to GSHc. We conclude that GSHn is associated with decreased oxidative signaling and stress responses and that whole cell redox homeostasis is restored as the cell cycle progresses by enhanced GSH synthesis and accumulation in the cytoplasm. Arabidopsis cells were harvested at points during cell proliferation where GSH was localized either in the nucleus (GSHn) or where GSH was distributed throughout the cytoplasm (GSHc) for RNA extraction and hybridization on Affymetrix microarrays. We selected three stages where the GSH was into the nucleus and three stages where the GSH was distributed throughout the cells.
2010-02-27 | E-GEOD-20454 | biostudies-arrayexpress
Project description:GSH, being a versatile molecule, is actively involved in various bilogical processe of plant system. Our previous studies identifies an active role of GSH in plant defense signaling network. Here, we used microarray under GSH treated condition to obtain a global expression profiling under this altered GSH conditions. We used microarrays to detail the global programme of gene expression underlying cellularisation and identified distinct classes of up-regulated genes during this process. A.thaliana, much accalimed model system of plant biology and being fully sequenced, we used this system to explore the specific relation of GSH with metabolic processes, phisiological conditions, etc.
2013-04-02 | E-GEOD-45677 | biostudies-arrayexpress