Project description:Here we have analyzed the role of interferon regulatory factor-2 binding protein-2 (IRF2BP2) in glucocorticoid and tumor necrosis factor alpha (TNF) signaling. We used ChIP-seq to analyze chromatin binding of IRF2BP2 in glucocorticoid (dexamethasone, dex) and vehicle treated HEK293 cells expressing GR (HEK293-GR). Furthermore, we used RNA-seq to analyze how silencing of IRF2BP2 modulates transcriptional responses to dex treatment in HEK293-GR cells, and dex, TNF and co-treatment (dex and TNF, DT) in A549 cells.
Project description:Long-term glucocorticoid treatment in multiple myeloma is hampered by deleterious side effects. Glucocorticoids bind to the glucocorticoid receptor (GR), which is a crucial drug target because its activation triggers myeloma cell death. The mineralocorticoid receptor (MR) is a closely related nuclear receptor but its impact on glucocorticoid responsiveness in myeloma is unknown. Here we reveal a functional crosstalk between GR and MR that culminates in improved myeloma cell killing. We show that the GR agonist Dexamethasone (Dex) downregulates MR levels in a GR-dependent way in myeloma cells. Co-treatment of Dex with the MR antagonist Spironolactone enhances Dex-induced cell killing in (primary) myeloma cells. The crosstalk is further evidenced by an endogenous interaction between GR and MR in myeloma cells that is ligand-inducible and by a distinctive gene expression profile. Our study demonstrates that GR-MR crosstalk is therapeutically relevant in myeloma and presents a glucocorticoid-based dose-reduction strategy that could diminish glucocorticoid-related side effects in patients.
Project description:The glucocorticoid receptor (GR) is a crucial drug target in multiple myeloma as its activation with glucocorticoids effectively triggers myeloma cell death. However, as high-dose glucocorticoids are also associated with deleterious side effects, novel approaches are urgently needed to improve GR’s action in myeloma. Here we reveal a functional crosstalk between GR and the mineralocorticoid receptor (MR) that culminates in improved myeloma cell killing. We show that the GR agonist Dexamethasone (Dex) downregulates MR levels in a GR-dependent way in myeloma cells. Co-treatment of Dex with the MR antagonist Spironolactone (Spi) enhances Dex-induced cell killing in primary, newly diagnosed GC-sensitive myeloma cells, while in a relapsed GC-resistant setting, Spi alone induces distinct myeloma cell killing. On a mechanistic level, we find that a GR-MR crosstalk is arising from an endogenous interaction between GR and MR in myeloma cells. Quantitative dimerization assays show that Spi reduces Dex-induced GR-MR heterodimerization and completely abolishes Dex-induced MR MR homodimerization but leaves GR-GR homodimerization intact. Unbiased transcriptomics further reveals that c-myc and many of its target genes are downregulated most by Dex and Spi combined, while proteomics analyses identify that several metabolic hallmarks are modulated most by this combination treatment. Finally, we identified a subset of Dex+Spi downregulated genes and proteins that may predict prognosis in the CoMMpass patient cohort. Our study demonstrates that GR-MR crosstalk is therapeutically relevant in myeloma as it provides novel strategies towards glucocorticoid-based dose-reduction.
Project description:Cortisol, the central stress hormone in humans, activates the glucocorticoid receptor (GR). Anti-inflammatory effects are the most important pharmaceutical effects mediated by the GR. Inasmuch as electrophilic cyclopentenone prostaglandin 15-deoxy-M-NM-^T12,14-prostaglandin J2 (15d-PGJ2) has potent anti-inflammatory properties and activates the SUMOylation pathway, we have investigated the effect of 15d-PGJ2 on glucocorticoid signaling and receptor SUMOylation. To this end, we studied isogenic HEK293 cells expressing either wild-type GR or SUMOylation-defective GR. Interestingly, 15d-PGJ2 triggered SUMO-2/3 modification in the primary SUMOylation sites of the GR. Gene expression profiling and pathway analyses indicate that 15d-PGJ2 inhibits GR signaling in a genome-wide fashion that is significantly dependent on the GR SUMOylation sites. Chromatin immunoprecipitation assays showed that the repressive effect of 15d-PGJ2 on GR target gene expression occurs in parallel with the inhibition of receptor binding to the target gene chromatin. Furthermore, depletion of the sole SUMO E2 conjugase UBC9 from HEK293 cells confirmed the involvement of active SUMOylation in the regulatory process. Taken together, our data indicate that GR SUMOylation modulates the glucocorticoid signaling during acute cell stress. Our data also suggest that GR SUMOylation modulates crosstalk of the glucocorticoid signaling with other transcription factors that are responsive to cell stress. Total RNA isolated from isogenic HEK293 cell lines stably expressing either wild-type GR (wtGR) or SUMOylation-defective GR (GR3KR) treated with 100 nM of dexamethasone (dex) in the presence or absence of 5 M-BM-5M 15d-PGJ2 for 6h. All conditions are performed in triplicate
Project description:Cortisol, the central stress hormone in humans, activates the glucocorticoid receptor (GR). Anti-inflammatory effects are the most important pharmaceutical effects mediated by the GR. Inasmuch as electrophilic cyclopentenone prostaglandin 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) has potent anti-inflammatory properties and activates the SUMOylation pathway, we have investigated the effect of 15d-PGJ2 on glucocorticoid signaling and receptor SUMOylation. To this end, we studied isogenic HEK293 cells expressing either wild-type GR or SUMOylation-defective GR. Interestingly, 15d-PGJ2 triggered SUMO-2/3 modification in the primary SUMOylation sites of the GR. Gene expression profiling and pathway analyses indicate that 15d-PGJ2 inhibits GR signaling in a genome-wide fashion that is significantly dependent on the GR SUMOylation sites. Chromatin immunoprecipitation assays showed that the repressive effect of 15d-PGJ2 on GR target gene expression occurs in parallel with the inhibition of receptor binding to the target gene chromatin. Furthermore, depletion of the sole SUMO E2 conjugase UBC9 from HEK293 cells confirmed the involvement of active SUMOylation in the regulatory process. Taken together, our data indicate that GR SUMOylation modulates the glucocorticoid signaling during acute cell stress. Our data also suggest that GR SUMOylation modulates crosstalk of the glucocorticoid signaling with other transcription factors that are responsive to cell stress.
Project description:TNF-a is a key regulator of innate immune and proinflammatory responses. However, the composition of the TNF-a receptor associated signaling complexes (TNF-RSC) and the architecture of the downstream signaling networks are incompletely understood. We employed quantitative mass spectrometry to demonstrate that TNF-a stimulation induces widespread protein phosphorylation and that the scope of phosphorylation expands in a temporal manner. TNF-a stimulation also induces rapid ubiquitylation of components of the TNF-RSC. Temporal analysis of the TNF-RSC composition identified SPATA2 as a novel component of the TNFRSC. The predicted PUB domain in the N-terminus of SPATA2 interacts with the USP domain of CYLD, whereas the C-terminus of SPATA2 interacts with HOIP. SPATA2 is required for recruitment of CYLD to the TNF-RSC. Downregulation of SPATA2 augments transcriptional activation of NF-jB and inhibits TNF-a-induced necroptosis, pointing to an important function of SPATA2 in modulating the outcomes of TNF-a signaling. Taken together, our study draws a detailed map of TNF-a signaling, identifies SPATA2 as a novel component of TNF-a signaling, and provides a rich resource for further functional investigations.
Project description:This study addressed mechanisms through which glucocorticoids exert repressive effects on pro-inflammatory TNF signaling using Global Run-on Sequencing (GRO-seq) in Beas-2B airway epithelial cells treated with dexamethasone and/or TNF for 10 or 30 minutes.
Project description:TNF-a is a key regulator of innate immune and proinflammatory responses. However, the composition of the TNF-a receptor associated signaling complexes (TNF-RSC) and the architecture of the downstream signaling networks are incompletely understood. We employed quantitative mass spectrometry to demonstrate that TNF-a stimulation induces widespread protein phosphorylation and that the scope of phosphorylation expands in a temporal manner. TNF-a stimulation also induces rapid ubiquitylation of components of the TNF-RSC. Temporal analysis of the TNF-RSC composition identified SPATA2 as a novel component of the TNFRSC. The predicted PUB domain in the N-terminus of SPATA2 interacts with the USP domain of CYLD, whereas the C-terminus of SPATA2 interacts with HOIP. SPATA2 is required for recruitment of CYLD to the TNF-RSC. Downregulation of SPATA2 augments transcriptional activation of NF-jB and inhibits TNF-a-induced necroptosis, pointing to an important function of SPATA2 in modulating the outcomes of TNF-a signaling. Taken together, our study draws a detailed map of TNF-a signaling, identifies SPATA2 as a novel component of TNF-a signaling, and provides a rich resource for further functional investigations.