The tumor suppressor FLCN mediates an alternate mTOR pathway to regulate browning of adipose tissue
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE89762 | GEO | 2016/11/11
SECONDARY ACCESSION(S): PRJNA353114
REPOSITORIES: GEO
Similar Datasets
Project description:Noncanonical mechanistic target of rapamycin (mTOR) pathways remain poorly understood. Mutations in the tumor suppressor folliculin (FLCN) cause Birt-Hogg-Dubé syndrome, a hamartomatous disease marked by mitochondria-rich kidney tumors. FLCN functionally interacts with mTOR and is expressed in most tissues, but its role in fat has not been explored. We show here that FLCN regulates adipose tissue browning via mTOR and the transcription factor TFE3. Adipose-specific deletion of FLCN relieves mTOR-dependent cytoplasmic retention of TFE3, leading to direct induction of the PGC-1 transcriptional coactivators, drivers of mitochondrial biogenesis and the browning program. Cytoplasmic retention of TFE3 by mTOR is sensitive to ambient amino acids, is independent of growth factor and tuberous sclerosis complex (TSC) signaling, is driven by RagC/D, and is separable from canonical mTOR signaling to S6K. Codeletion of TFE3 in adipose-specific FLCN knockout animals rescues adipose tissue browning, as does codeletion of PGC-1β. Conversely, inducible expression of PGC-1β in white adipose tissue is sufficient to induce beige fat gene expression in vivo. These data thus unveil a novel FLCN-mTOR-TFE3-PGC-1β pathway-separate from the canonical TSC-mTOR-S6K pathway-that regulates browning of adipose tissue.
| S-EPMC5159669 | biostudies-literature
Project description:In Birt-Hogg-Dubé (BHD) syndrome, germline mutations in the Folliculin (FLCN) gene lead to an increased risk of renal cancer. To address if FLCN is involved regulating cellular signaling pathways via protein and receptor phosphorylation we determined comprehensive complete phosphoproteomic profiles of FLCNPOS and FLCNNEG human renal tubular epithelial cells (RPTEC/TERT1). In total, 15744 phosphorylated peptides were identified, residing on 4329 phosphorylated proteins. Kinase activity inference analysis revealed that FLCN loss elevates phosphorylation of numerous kinases, including tyrosine kinases EPHA2 and MET, as well as activation of downstream MAPK1/3/6 and 8. Three non-canonical phosphorylation sites on EGFR (Tyr1125, Tyr1138 and Tyr1172) were higher phosphorylated upon FLCN loss together with enhanced phosphorylated EGFR substrates ABI, EPS8, ERRFL1, STAT1, PTK2 and CTNND1. In concordance, phosphosite specific signature analyses revealed an enrichment for EGFR signaling in FLCNNEG cells. Interestingly, we detected FLCN dependent phosphorylation of PIK3CD but no canonical downstream Akt/mTOR activation. In agreement with the induction of the E-box transcriptional gene expression signature upon FLCN loss, here we identified that phosphorylation of TFEB on Ser109, Ser114 and Ser122 is dependent on FLCN and absence of this phosphorylation results in constitutive nuclear localization of this transcription factor in FLCNNEG cells. Together, our study reveals enhanced phosphorylation of specific kinases and substrates in FLCNNEG renal epithelial cells, providing important insights in BHD-associated renal tumorigenesis and offering novel handles for the design of targeted therapies.
2022-07-11 | PXD025798 | Pride
Project description:The “Warburg effect” describes the use of aerobic glycolysis by cancer cells to fuel their growth. Lactate dehydrogenase-A (LDHA) is key to this process and catalyzes the interconversion of pyruvate and lactate. Here we used a proteomic approach to identify LDHA as a binding partner of the tumor suppressor FLCN. Canonically, LDHA is thought to be a substrate-regulated enzyme, however our data show that FLCN uncompetitively inhibits LDHA activity by restricting movement of its active site loop. This inhibition appears to be critical in normal cells, as we show FLCN binds to and tightly regulates LDHA activity in order to preserve metabolic homeostasis. Pathogenic mutations of FLCN are associated with LDHA hyperactivity and kidney tumor formation, suggesting a mechanism for FLCN tumor suppressive function. We have identified a cell-permeant ten amino acid peptide based on the FLCN sequence that enters these tumors and inhibits LDHA ex vivo. In a broader context, renal cell carcinomas experience the Warburg effect and show FLCN dissociation from LDHA. Cells that experience this metabolic shift depend on the hyperactivity of LDHA, as previous work has shown attenuation or inhibition of LDHA leads to programmed cell death. Treating these cells with the FLCN-derived peptide causes apoptosis, strongly suggesting that the glycolytic shift of cancer cells is the result of FLCN inactivation or disassociation from LDHA. Taken together, FLCN-mediated inhibition of LDHA provides a new paradigm for the regulation of glycolysis.
2021-08-05 | PXD018410 | Pride
Project description:UOK257 cell line was derived from a BHD patient. It harbors a germline mutation in FLCN (c.1285dupC) and LOH. UOK257-2 cells were generated from UOK257 cells by introducing wildtype FLCN using retrovirus. FLCN inactivation induces TFE3 transcriptional activity by increasing its nuclear localization. Thus expression microarray was used to identify the genes regulated by FLCN and TFE3. UOK257-2 cells expressing wildtype FLCN were transfected with 1) scrambled, 2) FLCN, 3) TFE3 and 4)FLCN/TFE3 siRNAs with Lipofectamine 2000 transfection reagent. Cells were harvested 3 days after transfection and RNAs were isolated using Trizol reagent and RNeasy Mini Kit. The genes induced by FLCN siRNA and reduced by TFE3 siRNA were chosen as a candidate genes regulated by FLCN and TFE3.
2010-10-11 | E-GEOD-23614 | biostudies-arrayexpress
Project description:Growing tumors exist in metabolically compromised environments that require activation of multiple pathways to scavenge nutrients to support accelerated rates of growth. The FLCN tumor suppressor complex (FLCN, FNIP1, FNIP2) has been implicated in the regulation of energy homeostasis via two metabolic master kinases: AMPK and mTORC1. Loss-of-function mutations of the FLCN tumor suppressor complex have only been reported in renal tumors in patients with the rare Birt-Hogg-Dube syndrome. Here we reveal that FLCN, FNIP1, and FNIP2 are downregulated in many human cancers including poor prognosis invasive basal-like breast carcinomas where AMPK and TFE3 targets are activated compared to the luminal, less aggressive subtypes. We show that FLCN loss in luminal subtypes promotes tumor growth through TFE3 activation and subsequent induction of several pathways including autophagy, lysosomal biogenesis, aerobic glycolysis, and angiogenesis. Strikingly, induction of aerobic glycolysis and angiogenesis in FLCN deficient cells was dictated by the activation of PGC-1⍺/HIF-1⍺ pathway, which we show to be TFE3-dependent, directly linking TFE3 to Warburg metabolic reprogramming and angiogenesis. Thus, FLCN loss induces TFE3-dependent breast tumor growth through activation of multiple mechanisms, including previously unreported roles in aerobic glycolysis and angiogenesis. These findings could point to a general role of a deregulated FLCN/TFE3 tumor suppressor pathway in human cancers.
2020-12-23 | GSE163791 | GEO
Project description:UOK257 cell line was derived from a BHD patient. It harbors a germline mutation in FLCN (c.1285dupC) and LOH. UOK257-2 cells were generated from UOK257 cells by introducing wildtype FLCN using retrovirus. FLCN inactivation induces TFE3 transcriptional activity by increasing its nuclear localization. Thus expression microarray was used to identify the genes regulated by FLCN and TFE3.
2010-10-11 | GSE23614 | GEO
Project description:Targeted disruption of Flcn in mouse kidney proximal tubule gives insights into human BHD renal tumorigenesis Mouse Tumor kidney tissue vs. normal kidney tissue
2014-07-28 | E-GEOD-49397 | biostudies-arrayexpress
Project description:Targeted disruption of Flcn in mouse kidney proximal tubule gives insights into human BHD renal tumorigenesis
2014-07-28 | GSE49397 | GEO
Project description:Birt-Hogg-Dubé syndrome is an autosomal dominantly inherited disorder that is characterized by the clinical triad of benign skin tumors - so-called fibrofolliculomas, recurrent pneumothoraces due to pulmonary cysts and the formation of kidney tumors. The molecular function of Folliculin (FLCN), the protein product of the BHD gene mutated in this syndrome, has remained elusive to a large extent. Animal models such as mouse, rat and canine models have been used to elucidate parts of the pathway in which FLCN plays a role showing it to interfere with AMP-kinase and mTOR signaling. Caenorhabditis elegans provides - due to its simple genetic amenability and large brood size - the perfect tool to study signal transduction pathways in detail. Thus, we decided to examine F22D3.2 (flcn-1) - a putative orthologue of FLCN in the nematode. We established the first gene expression profiles of a strain harboring a mutation in flcn-1 compared to WTN2 allowing for a first insight into the function of this gene in C. elegans. This study examines the transcriptome of the flcn-1 mutant strain RB1035 in comparison to WTN2 in order to identify differentially regulated genes. RNA was prepared from pre-reproductive adults in both WTN2 and RB1035 (harboring a flcn-1 mutant allele, mutant worms had been backcrossed wo WTN2 8 times) using biological triplicates. RNA was labeled and hybridized to Agilent C. elegans whole genome microarrays and scanned using a Agilent Technologies Scanner G2505C US22502540.
2012-12-31 | E-GEOD-43207 | biostudies-arrayexpress
Project description:Birt-Hogg-Dubé syndrome is an autosomal dominantly inherited disorder that is characterized by the clinical triad of benign skin tumors - so-called fibrofolliculomas, recurrent pneumothoraces due to pulmonary cysts and the formation of kidney tumors. The molecular function of Folliculin (FLCN), the protein product of the BHD gene mutated in this syndrome, has remained elusive to a large extent. Animal models such as mouse, rat and canine models have been used to elucidate parts of the pathway in which FLCN plays a role showing it to interfere with AMP-kinase and mTOR signaling. Caenorhabditis elegans provides - due to its simple genetic amenability and large brood size - the perfect tool to study signal transduction pathways in detail. Thus, we decided to examine F22D3.2 (flcn-1) - a putative orthologue of FLCN in the nematode. We established the first gene expression profiles of a strain harboring a mutation in flcn-1 compared to WTN2 allowing for a first insight into the function of this gene in C. elegans. This study examines the transcriptome of the flcn-1 mutant strain RB1035 in comparison to WTN2 in order to identify differentially regulated genes.
2012-12-31 | GSE43207 | GEO