SGK3 Orchestrates Glucocorticoid Signaling to Facilitate Chromatin Remodeling During Adipogenesis
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ABSTRACT:
PROVIDER: PRJNA1116801 | ENA |
REPOSITORIES: ENA
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Project description:Excessive glucocorticoid exposure is associated with significant metabolic side effects, partly attributed to the transcriptional regulation of adipogenesis by the Glucocorticoid receptor (GR). However, emerging evidence suggests the involvement of alternative pathways beyond GR activation, which are inadequately explored. Through quantitative phosphoproteomics analysis, we identified a significant enrichment of rapidly phosphorylated proteins harboring the RxxS motif following glucocorticoid exposure. Notably, a subset of these proteins undergoes phosphorylation at the RxxS motif by Serum- and glucocorticoid-induced kinase 3 (SGK3) upon glucocorticoid stimulation in preadipocytes. SGK3 emerges as a critical mediator of glucocorticoid-induced preadipocyte differentiation, supported by genetic ablation and pharmacological inhibition experiments that demonstrate impaired adipogenesis both in vitro and in vivo. Mechanistically, upon glucocorticoid stimulation, SGK3 translocates to the nucleus and directly interacts with the core ATPase subunit of the BAF chromatin remodeling complex, BRG1, leading to phosphorylation at threonine 428 and serine 1417 residues. This phosphorylation event prevents proteasomal degradation of BRG1, facilitating chromatin remodeling essential for adipogenesis. Furthermore, Sgk3 knockout mice exhibit resistance to obesity induced by either glucocorticoids or a high-fat diet (HFD). These findings illuminate novel roles of glucocorticoids beyond GR-mediated transcriptional control, highlighting SGK3 as a promising therapeutic target for mitigating metabolic side effects associated with glucocorticoid therapy.
2025-07-15 | GSE268382 | GEO
Project description:Serum- and glucocorticoid-regulated kinase 3 (Sgk3) is activated by the phospholipid 19 phosphatidylinositol-3-phosphate (PI3P) downstream of growth factor signaling and 20 by Vps34-mediated PI3P production during autophagy. Upregulation of Sgk3 activity 21 has been linked to a number of human cancers due to its overlapping substrate 22 specificity with Akt. Here, we show that Sgk3 is regulated by a combination of 23 phosphorylation and allosteric activation by PI3P. We demonstrate that Sgk3 is 24 specifically activated by PI3P and that PI3P binding induces large conformational 25 changes in Sgk3. Using Vps34 and liposomes containing phosphatidylinositol, we 26 reconstitute Sgk3 signaling via Vps34-mediated PI3P synthesis in vitro. In addition to 27 defining the mechanism of Sgk3 activation by PI3P, our findings open up potential 28 therapeutic avenues in allosteric inhibitor development to target Sgk3 in cancer.
2021-09-22 | PXD025327 | Pride
Project description:The Wnt/b-catenin signaling inhibits adipogenesis. Genome-wide profiling studies have revealed the enrichment of histone H3K27 methyltransferase PRC2 on Wnt genes. However, the functional significance of such a direct link between the two types of developmental regulators in mammalian cells, and the role of PRC2 in adipogenesis, remain unclear. Here we show PRC2 and its H3K27 methyltransferase activity are required for adipogenesis. PRC2 directly represses Wnt1, 6, 10a and 10b genes in preadipocytes and during adipogenesis. Deletion of the enzymatic Ezh2 subunit of PRC2 eliminates H3K27me3 on Wnt promoters and de-represses Wnt expression, which leads to activation of Wnt/b-catenin signaling and inhibition of adipogenesis. Ectopic expression of the wild type Ezh2, but not the enzymatically inactive F667I mutant, prevents the loss of H3K27me3 and the defects in adipogenesis in Ezh2-/- preadipocytes. The adipogenesis defects in Ezh2-/- cells can be rescued by expression of adipogenic transcription factors PPARa, C/EBPb, or inhibitors of Wnt/b-catenin signaling. Interestingly, Ezh2-/- cells show marked increase of H3K27 acetylation globally as well as on Wnt promoters. These results indicate that H3K27 methyltransferase PRC2 directly represses Wnt genes to facilitate adipogenesis, and suggest that acetylation and trimethylation on H3K27 play opposing roles in regulating Wnt expression. To identify additional PRC2-regulated genes in preadipocytes, we performed microarray analysis in Ezh2flox/flox preadipocytes infected with retroviruses expressing Cre or vector alone.
2010-03-19 | E-GEOD-20054 | biostudies-arrayexpress
Project description:The Wnt/b-catenin signaling inhibits adipogenesis. Genome-wide profiling studies have revealed the enrichment of histone H3K27 methyltransferase PRC2 on Wnt genes. However, the functional significance of such a direct link between the two types of developmental regulators in mammalian cells, and the role of PRC2 in adipogenesis, remain unclear. Here we show PRC2 and its H3K27 methyltransferase activity are required for adipogenesis. PRC2 directly represses Wnt1, 6, 10a and 10b genes in preadipocytes and during adipogenesis. Deletion of the enzymatic Ezh2 subunit of PRC2 eliminates H3K27me3 on Wnt promoters and de-represses Wnt expression, which leads to activation of Wnt/b-catenin signaling and inhibition of adipogenesis. Ectopic expression of the wild type Ezh2, but not the enzymatically inactive F667I mutant, prevents the loss of H3K27me3 and the defects in adipogenesis in Ezh2-/- preadipocytes. The adipogenesis defects in Ezh2-/- cells can be rescued by expression of adipogenic transcription factors PPARa, C/EBPb, or inhibitors of Wnt/b-catenin signaling. Interestingly, Ezh2-/- cells show marked increase of H3K27 acetylation globally as well as on Wnt promoters. These results indicate that H3K27 methyltransferase PRC2 directly represses Wnt genes to facilitate adipogenesis, and suggest that acetylation and trimethylation on H3K27 play opposing roles in regulating Wnt expression.
2010-03-19 | GSE20054 | GEO
Project description:Deregulation of the PI3K/Akt pathway is a common feature in many types of cancer. Recent data has demonstrated that prolonged inhibition of breast cancer cell lines with PI3K and Akt inhibitors leads to up-regulation and increased activity of the AGC kinase Serum and glucocorticoid activated kinase 3, SGK3, which in turn substitutes for Akt and leads to activation of mTORC1. SGK3 and Akt exhibit similar substrate specificity for Ser/Thr residues in the RxRxxS/T motif. However, SGK3 can be regulated by both PI3K class I and class III and possesses a unique PX domain, enabling it to bind to PI(3)P lipids in endosomes. Still, the known SGK3 substrates are either shared or have not been tested whether Akt can phosphorylate them. In the present study, we undertook genetic and pharmacologic phosphoproteomic screens to search for selective SGK3 substrates. We identified a significant number of potential in vivo SGK3 selective substrates, including the endosomal proteins STX7, STX12, RFIP4 and WDR44. In vitro phosphorylation studies demonstrated that these substrates were directly phosphorylated at the sites identified in vivo by SGK3 but, unlike all other SGK3 substrates reported, not by Akt. We provide evidence that endogenous STX7 and STX12 are physiological SGK3 substrates whose phosphorylation is potently stimulated by IGF1. Our data pinpoint that STX7 and STX12 are the first selective SGK3 substrates in vivo and this phosphorylation enhances their interaction with the respective SNARE complexes. Finally, we suggest that STX7 and STX12 phosphorylation can be utilised as in vivo biomarkers for SGK3 activity.
2020-05-26 | PXD014561 | Pride
Project description:SGK3 is a PX domain containing protein kinase activated at endosomes downstream of Class 1 and 3 PI3K family members by growth factors and oncogenic mutations. SGK3 plays a key role in mediating resistance of breast cancer to Class 1 PI3K or Akt inhibitors, by substituting for loss of Akt and restoring proliferative pathways such as mTORC1 signaling. Here we describe the development of SGK3-PROTAC1, a Proteolysis Targeting Chimera (PROTAC) compound formed by the fusion of the 308-R SGK3 inhibitor with the VH032 VHL binding ligand via a 13-atom linker. In HEK293 cells, 0.3 µM SGK3-PROTAC1 induced 50% degradation of endogenous SGK3 within 2 hours, with maximal 85% degradation observed within 8 hours, accompanied by a loss of phosphorylation of NDRG1, an SGK3 substrate. SGK3-PROTAC1 did not degrade closely related SGK1 and SGK2 isoforms and proteomic analysis in HEK293 cells revealed that SGK3 was the only cellular protein whose cellular levels was significantly reduced following treatment with SGK3-PROTAC1. Low doses of SGK3-PROTAC1 (0.1-0.3 µM) restored sensitivity of SGK3 dependent ZR-75-1 and CAMA-1 breast cancer cells to Akt (AZD5363) and PI3K (GDC0941) inhibitors, under conditions which an epimer analogue incapable of binding to the VHL E3 ligase had no impact. SGK3-PROTAC1 suppressed proliferation of ZR-75-1 and CAMA-1 cancer cell lines treated with a PI3K inhibitor (GDC0941) more effectively than could be achieved by a conventional SGK isoform inhibitor (14H). This work provides a further example of the benefit of the PROTAC approach in targeting protein kinase signaling pathways with greater efficacy and selectivity than can be achieved with conventional inhibitors. SGK3-PROTAC1 will be an important reagent to explore the roles of the SGK3 pathway.
2019-11-12 | PXD013779 | Pride
Project description:Neurological toxicity, including brain atrophy, is a commonly observed side effect of chemotherapy, often referred to as "chemotherapy brain," particularly prevalent among young cancer patients with developmental disorders. Methotrexate (MTX), a widely used chemotherapeutic reagent and immunosuppressive medication, is associated with a spectrum of adverse effects. While many researchers have highlighted neurotoxic-related issues in both cancer patients and animals treated with MTX, the mechanism of chemotherapy's impact on brain development, including in children or fetuses, remains poorly understood. In this study, we investigate the effects of MTX exposure on brain cortical organoids (COs), three-dimensional in vitro models designed to mimic human cortex development. Our primary objective is to assess their potential for exhibiting developmental toxicity when exposed to MTX. We observed a significant decrease in both the size and viability of COs morphologically and statistically after MTX exposure (MTX COs) on day 45 of differentiation. Additionally, compared with control COs, the MTX COs showed increased expression of immature neuron and GABAergic neuron-related genes. Furthermore, we detected a significant increase in intracellular ROS levels and the expression of ER-stress, cell cycle, and DNA damage-related genes in MTX COs. The expression of the apoptosis-related protein, cleaved caspase-3, was also significantly elevated in the MTX COs. Moreover, through RNA sequencing analysis, we found a significant decrease in SGK3 (serum/glucocorticoid-regulated kinase family member 3), a regulator gene of proliferation, in MTX COs. Consequently, our findings suggest that MTX could impact cortex development in the brain by increasing intracellular ROS and ER stress, ultimately inducing apoptosis, possibly through the inhibition of the SGK3 pathway. Understanding the developmental neurotoxicity of MTX in brain COs is crucial, as it provides valuable insights into the risk factors associated with prenatal exposure to the drug.
2025-03-31 | GSE262517 | GEO
Project description:Differentiation of 3T3-L1 preadipocytes can be induced by a 2-d treatment with a factor "cocktail" (DIM) containing the synthetic glucocorticoid dexamethasone (dex), insulin, the phosphodiesterase inhibitor methylisobutylxanthine (IBMX) and fetal bovine serum (FBS). We temporally uncoupled the activities of the four DIM components and found that treatment with dex for 48 h followed by IBMX treatment for 48 h was sufficient for adipogenesis, whereas treatment with IBMX followed by dex failed to induce significant differentiation. Similar results were obtained with C3H10T1/2 and primary mesenchymal stem cells. The 3T3-L1 adipocytes differentiated by sequential treatment with dex and IBMX displayed insulin sensitivity equivalent to DIM adipocytes, but had lower sensitivity to isoproterenol-stimulated lipolysis and reduced triglyceride content. The nondifferentiating IBMX–then-dex treatment produced transient expression of adipogenic transcriptional regulatory factors C/EBP{beta} and C/EBP{delta}, and little induction of terminal differentiation factors C/EBP{alpha} and PPAR{gamma}. Moreover, the adipogenesis inhibitor preadipocyte factor-1 (Pref-1) was repressed by DIM or by dex-then-IBMX, but not by IBMX-then-dex treatment. We conclude that glucocorticoids drive preadipocytes to a novel intermediate cellular state, the dex-primed preadipocyte, during adipogenesis in cell culture, and that Pref-1 repression may be a cell fate determinant in preadipocytes.
2008-07-25 | GSE11249 | GEO
Project description:Differentiation of 3T3-L1 preadipocytes can be induced by a 2-d treatment with a factor "cocktail" (DIM) containing the synthetic glucocorticoid dexamethasone (dex), insulin, the phosphodiesterase inhibitor methylisobutylxanthine (IBMX) and fetal bovine serum (FBS). We temporally uncoupled the activities of the four DIM components and found that treatment with dex for 48 h followed by IBMX treatment for 48 h was sufficient for adipogenesis, whereas treatment with IBMX followed by dex failed to induce significant differentiation. Similar results were obtained with C3H10T1/2 and primary mesenchymal stem cells. The 3T3-L1 adipocytes differentiated by sequential treatment with dex and IBMX displayed insulin sensitivity equivalent to DIM adipocytes, but had lower sensitivity to isoproterenol-stimulated lipolysis and reduced triglyceride content. The nondifferentiating IBMX–then-dex treatment produced transient expression of adipogenic transcriptional regulatory factors C/EBP{beta} and C/EBP{delta}, and little induction of terminal differentiation factors C/EBP{alpha} and PPAR{gamma}. Moreover, the adipogenesis inhibitor preadipocyte factor-1 (Pref-1) was repressed by DIM or by dex-then-IBMX, but not by IBMX-then-dex treatment. We conclude that glucocorticoids drive preadipocytes to a novel intermediate cellular state, the dex-primed preadipocyte, during adipogenesis in cell culture, and that Pref-1 repression may be a cell fate determinant in preadipocytes. We sought to define the genes differentially expressed in response to dexamethasone (dex) in 3T3L1 mouse preadipocytes. We treated 3T3L1 cells with dex or DMSO vehicle for 2 or 36 hrs and then prepared total RNA. We hybridized each sample (Cy5) to a pool of the samples, which served as the reference (Cy3) channel. All linear models for differential gene expression were constructed with the "limma" package (Smyth, 2004) in BioConductor (Gentleman et al., 2004). A linear model for dex was constructed to compare the 4 biological replicates of DMSO vehicle treatment with dex treatment at either 2 or 36hr. Genes were considered differentially expressed if at least one probe had log-odds greater than 50:50 in the linear model.
2008-07-25 | E-GEOD-11249 | biostudies-arrayexpress
Project description:<p>Cold exposure induces beige adipogenesis in white adipose tissue (iWAT), enhancing thermogenesis and energy expenditure. While gut microbiota-derived metabolites are known to regulate host metabolism, their role in thermogenic adaptation remains poorly defined. Here, we identify Prevotella copri (P. copri) as a key microbial mediator of cold-induced adipose remodeling. Cold exposure expands the population of P. copri in the colonic contents, and we found that this species that produces 3-phenylpropionic acid (3-PPA) to promote beige adipocyte formation and enhances energy expenditure. Mechanistically, 3-PPA signals through free fatty acid receptor 1 (Ffar1/Gpr40) in M2-like macrophages, inducing C-X-C motif chemokine 13 (CXCL13) secretion that in turn recruits T follicular helper (Tfh) cells to facilitate beige adipogenesis. By lineage-tracing analyses, we reveal that adipocyte progenitor cells contribute to 3-PPA-driven beige fat formation. Moreover, 3-PPA supplementation counteracts high-fat diet–induced obesity in mice and promotes thermogenesis in mouse, pig, and human adipose progenitor cells. These findings define a gut microbiota–immune cell-adipose progenitor cell axis that regulates cold adaptation, highlighting microbial metabolites as potential therapeutic targets for metabolic diseases.</p>
2025-12-13 | MTBLS13503 | MetaboLights