Tuberous sclerosis complex-associated CNS abnormalities depend on hyperactivation of mTORC1 and Akt
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PROVIDER: PRJNA430419 | ENA |
REPOSITORIES: ENA
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Project description:Tuberous sclerosis complex (TSC) is a dominantly inherited disease, caused by hyperactivation of the mTORC1 pathway and characterized by the development of hamartomas and benign tumors, also in the brain. Among the neurological manifestations associated with TSC, the tumor progression of static subependymal nodules (SENs) into subependymal giant cell astrocytomas (SEGAs) is one of the major causes of morbidity and shortened life expectancy. To date, mouse modeling has failed in reproducing these two lesions. Here we report that simultaneous hyperactivation of mTORC1 and Akt pathways by co-deletion of Tsc1 and Pten, selectively in postnatal neural stem cells (pNSCs), is required for the formation of bona fide SENs and SEGAs. Notably, both lesions closely recapitulate the pathognomonic morphological and molecular features of the corresponding human abnormalities. The establishment of long-term expanding pNSC lines from mouse SENs and SEGAs made possible the identification of mTORC2 as one of the mediators conferring tumorigenic potential to SEGA pNSCs. Of note, in spite of concurrent Akt hyperactivation in mouse brain lesions, single mTOR inhibition by rapamycin was sufficient to strongly impair mouse SEGA growth. This study provides the first evidence that, concomitant with mTORC1 hyperactivation, sustained activation of Akt and mTORC2 in pNSCs is a mandatory step for the induction of SENs and SEGAs and, at the same time, makes available an unprecedented NSC-based in vivo/in vitro model to be exploited for identifying actionable targets in TSC.
2018-02-14 | GSE109321 | GEO
Project description:Tuberous Sclerosis Complex (TSC) is caused by germline TSC1 or TSC2 mutations, leading to hyperactivation of mechanistic target of rapamycin complex 1 (mTORC1) and tumors in multiple organs including the brain, heart, lung (lymphangioleiomyomatosis), and kidney (angiomyolipoma and renal cell carcinoma). Previously, we found that TFEB is constitutively active in models of TSC. To determine the impact of TFEB in vivo, we generated two novel mouse models of TSC, resulting in premature death, in which kidney pathology was the primary phenotype. RNA sequencing revealed that lysosomal and proteasomal gene pathways were the most highly upregulated in the TSC2-deficient kidneys. Knockout of TFEB rescued both kidney pathology and overall survival in both models, indicating that TFEB is the primary driver of renal disease in TSC. Importantly, mTORC1 activity, which was elevated in the TSC2 knockout kidneys, was normalized by TFEB knockout. Knockdown of Rheb or treatment of TSC2-deficient cells with Rapamycin paradoxically increases TFEB phosphorylation at the mTORC1-site (S211) and relocalizes TFEB from the nucleus to the cytoplasm via a Rag-dependent mechanism. Accordingly, treatment of TSC2 knockout mice with Rapamycin normalized lysosomal gene expression, similar to TFEB knockout, suggesting that the beneficial effects of Rapamycin in TSC are TFEB-dependent. These results change the view of the mechanisms leading to mTORC1 hyperactivation in TSC and may lead to novel therapeutic avenues for the treatment of TSC.
2023-09-28 | GSE244072 | GEO
Project description: Not available
| S-EPMC5873854 | biostudies-literature
Project description:The aim of the study is to investigate the role and mechanisms of tuberous sclerosis complex 1 (TSC1) and mechanistic target of rapamycin complex 1 (mTORC1) in alcohol associated liver disease Hepatic RNA profiles of WT and hepatic TSC1 KO mice fed with alcohol or control diet using Gao binge alcohol model.
2023-04-25 | GSE230175 | GEO
Project description:Gp130 receptor engagement on neoplastic cells provides a link by which an inflammatory microenvironment facilitates tumour promotion. Although hyperactivation of the gp130-dependent Stat3 signalling node is commonly observed in solid tumours, Stat3 remains a challenging therapeutic target. To mimic excessive Stat3 signalling, we molecularly validate the gp130FF mouse as a preclinical model for inflammation-associated intestinal-type gastric cancer (IGC), with aberrant mammalian target of rapamycin (mTOR) pathway activity as shared feature. Accordingly, administration of the mTorc1 inhibitor RAD001 reversibly reduced IGC burden in gp130FF mice and suppressed colitis-associated cancer in wild-type mice. Since the therapeutic effect of RAD001 occurs independently of Stat3 hyperactivation, which is also dispensable for gp130-dependent engagement of the PI3K/Akt/mTorc1 pathway, we conclude that mTorc1 signalling limits tumour promoting Stat3 activity The mouse whole-genome gene expression profiling was performed on Illumina's MouseWG-6 v2.0 Expression BeadChips for 24 mice, with 8 mice in each group (gp130WT antral tissue, gp130FF unaffected antral tissue and gp130FF tumour tissue).
2013-01-29 | E-GEOD-35808 | biostudies-arrayexpress
Project description:Many biological processes involve the mechanistic/mammalian target of rapamycin complex 1 (mTORC1). Thus, the challenge of deciphering mTORC1-mediated functions during normal and pathological states in the central nervous system is steep. Because mTORC1 is at the core of translation, we have investigated mTORC1 function in global and regional protein expression. Activation of mTORC1 has been generally regarded to promote translation. Few but recent works have demonstrated that suppression of mTORC1 can promote local protein synthesis. Moreover, excessive mTORC1 activation during disease states represses basal and activity-induced protein synthesis. To determine the role of mTORC1 activation in protein expression, we have used an unbiased, large scale proteomic approach. We provide evidence that a brief repression of mTORC1 activity in vivo by rapamycin has little affect globally, yet leads to a significant remodeling of synaptic proteins, in particular those proteins that reside in the postsynaptic density (PSD). We have also found that curtailing the activity of mTORC1 bidirectionally alters the expression of proteins associated with epilepsy, Alzheimer’s disease, and autism spectrum disorder (ASD)—neurological disorders that exhibit elevated mTORC1 activity. Through a protein-protein interaction network analysis, we have identified common proteins shared among these mTOR-related diseases. One such protein is Parkinson protein 7 (PARK7) which has been implicated in Parkinson’s disease, yet not associated with epilepsy, AD, or ASD. To verify our finding, we provide evidence that the protein expression of PARK7, including new protein synthesis, is sensitive to mTORC1 inhibition. Using cultured neurons from a mouse model of tuberous sclerosis complex (TSC), a disease that displays both epilepsy and ASD phenotypes and has overactive mTOR signaling, we show that PARK7 protein is elevated in the dendrites. Our work offers a comprehensive view of mTORC1 and its role in regulating regional protein expression in normal and diseased states.
2016-02-19 | PXD002724 | Pride
Project description:The mechanistic target of rapamycin complex 1 (mTORC1) is an important regulator of cellular metabolism that is commonly hyperactivated in cancer. Recent cancer genome screens have identified multiple mutations in Ras-homolog enriched in brain (Rheb), the primary activator of mTORC1, that might act as driver oncogenes through aberrant hyperactivation of mTORC1. Here, we show that a number of recurrently occurring Rheb mutants drive hyperactive mTORC1 signalling through differing levels of insensitivity to the primary inactivator of Rheb, Tuberous Sclerosis Complex. We show that two activated mutants, Rheb-T23M and E40K, strongly drive increased cell growth and proliferation and anchorage-independent growth resulting in enhanced tumour growth in vivo. Proteomic analysis of cells expressing the mutations revealed, surprisingly, that these two mutants promote distinct oncogenic pathways with Rheb-T23M driving metabolic reprogramming and an increased reliance of glycolysis, while Rheb-E40K interacts with AMPK to regulate eukaryotic elongation factor 2 (eEF2) and autophagy. Our findings suggest that unique ‘bespoke’ combination therapies may be utilised to treat cancers according to which Rheb mutant they harbour.
2021-04-22 | PXD017006 | Pride
Project description:The mechanisms that regulate T cell quiescence are poorly understood. We report that tuberous sclerosis complex 1 (Tsc1) establishes a quiescent program in naïve T cells by controlling cell size, cell cycle entry, and responses to T cell receptor stimulation. Loss of quiescence predisposed Tsc1-deficient T cells to apoptosis that depleted conventional T cells and invariant natural killer T cells. Loss of Tsc1 function dampened in vivo immune responses to bacterial infection. Tsc1-deficient T cells exhibited increased mTORC1 but diminished mTORC2 activities, with mTORC1 activation essential for the disruption of immune homeostasis. Therefore, Tsc1-dependent control of mTOR is crucial in establishing naïve T cell quiescence to facilitate adaptive immune function. Naïve CD4 and CD8 T cells from wild-type and Tsc1-deficient mice (in triplicates each group) were stimulated with or without TCR signaling. RNA was analyzed by microarrays. WT/KO for 0 and 4 hr for CD4 (triplicates), and WT/KO for 0 hr for CD8 (duplicates).
2011-07-11 | E-GEOD-29797 | biostudies-arrayexpress
Project description:The PI3K-AKT-mTOR pathway is commonly dysregulated in cancer. Rapalogs exhibit modest clinical benefit likely due to their lack of effects on 4E-BP1. We hypothesized that bi-steric mTORC1-selective inhibitors would have greater potential for clinical benefit than rapalogs in tumors with mTORC1 dysfunction. We assessed this hypothesis in tumor models with high mTORC1 activity both in vitro and in vivo. Bi-steric inhibitors had strong growth inhibition, eliminated phosphorylated 4EBP1, and induced more apoptosis than rapamycin or MLN0128. Multi-omic analysis showed extensive effects of the bi-steric inhibitors in comparison to rapamycin. De novo purine synthesis was markedly and selectively inhibited by bi-sterics through reduction in JUN and its downstream target PRPS1 and appeared to be the cause of apoptosis. Hence, bi-steric mTORC1-selective inhibitors are a novel therapeutic strategy to treat tumors driven by mTORC1 hyperactivation.
2023-11-08 | GSE236742 | GEO
Project description:Distinct molecular subgroups and subtypes have been identified for medulloblastoma (MB), one of the most malignant brain tumors of childhood, with the sonic hedgehog (SHH)-activated subgroup of patients with mutations in p53 having a very severe outcome, associated with unfavorable histological large cell/anaplastic (LC/A) features. Aim of this study was to determine whether hyperactivation of mechanistic Target Of Rapamycin Complex 1 (mTORC1) pathway, whose role in molecular subtypes of MB is currently undefined, underlies the acquisition of LC/A histology in this subtype. MBs developing in p53-deficient Ptch+/- SHH mice show LC/A features that correlate with mTORC1 hyperactivation, which, mechanistically, is mediated by a decrease in the p53-dependent expression of the negative mTORC1 regulator Tsc2. Ectopic mTORC1 activation in mouse MB cancer stem cells (CSCs) promotes the acquisition of the LC/A phenotype. Furthermore, mTORC1 inhibition in both autochthonous p53-mutant SHH MBs and CSC-derived LC/A MBs results in reduced tumor burden and enhanced survival. Most remarkably, mTORC1 hyperactivation in tumor cells is detected only in human p53-mutant SHH MB samples and treatment with rapamycin of a human preclinical model phenocopying this subgroup decreases tumor growth and malignancy. As such, mTORC1 may act as a new and specific druggable target for this subset of SHH MB, thus resulting in the implementation of a more stringent MB risk stratification and in the potentially rapid translation of this precision medicine approach into the clinical setting.
2021-10-21 | GSE183901 | GEO