Inhibition of BRD4 Attenuates ER Stress-induced Renal Ischemic-Reperfusion Injury
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE217103 | GEO | 2024/02/15
REPOSITORIES: GEO
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Project description:Selective bromodomains inhibitors block the interaction between diverse bromodomains and extraterminal domains (BET) proteins and acetylated proteins. These inhibitors have shown beneficial effects in cancers malignancies and experimental inflammation in mouse models, but data on renal diseases are scarce. We have investigated the effect of the BET proteins inhibitor JQ1 in a mice model of unilateral ureteral obstruction. Treatment with JQ1 diminished renal damage, the presence of inflammatory cell infiltration and the upregulation of proinflammatory genes. The in vitro evaluation of JQ1 on TNF-α inducible genes in renal cells showed that BET inhibition modulated several biological processes, including inflammation or immune response. Moreover, gene-silencing experiments showed that BRD4 regulates several proinflammatory genes (IL-6, CCL-2 and CCL-5) and chromatin immunoprecipitation techniques demonstrated that BRD4 specifically binds to acetylated histone H3 in the promoter region of those genes. The nuclear factor-ï«B (NF-ï«B) pathway regulates renal inflammation. The RelA NF-ï«B subunit is activated by acetylation of lysine 310. In damaged kidneys and in TNF-α-treated renal cells, JQ1 blocked the nuclear translocation of RelA/NF-ï«B and NF-ï«B-mediated gene expression. Additionally, obstructed kidneys showed an activation of the Th17 immune response, which was diminished by JQ1 treatment. Our results demonstrate that the BET inhibition decreases renal inflammation by 3 independent mechanisms: 1) chromatin remodelling in the promoter regions of specific genes, 2) blocking NF-ï«B pathway activation, and 3) modulating the Th17 immune response. These results suggest that BET inhibitors could have important therapeutic applications in inflammatory renal diseases. HK2 cell line was treated with JQ1 or its enantiomer JQ1(-) (500nM) for 1 hour before stimulation or not with TNF-α (5ng/ml) for additional 3h. We analized the genes up- and down-regulated by TNF-α vs unstimulated cells, and further the genes downregulated or unaffected by JQ1 compared to the cells treated with the enantiomer (-) JQ1.
2016-07-01 | E-GEOD-71602 | biostudies-arrayexpress
Project description:Transcription factor GATA1 binding in erythroblasts in the presence and absence of BET inhibitor JQ1, and BET protein BRD3 and BRD4 binding in erythroblasts in the presence and absence of GATA1. Inhibitors of Bromodomain and Extra-Terminal motif proteins (BETs) are being evaluated for the treatment of cancer and other diseases yet their physiologic mechanisms remain largely unknown. We used genomic and genetic approaches to examine BET function in a hematopoietic maturation system driven by GATA1, an acetylated transcription factor previously shown to interact with BETs. We found that while BRD3 occupied the majority of GATA1 binding sites, BRD2 and BRD4 were also recruited to a subset of GATA1-occupied sites. Functionally, BET inhibition impaired GATA1-mediated transcriptional activation, but not repression, genome-wide. Co-activation by BETs was accomplished both by facilitating genomic occupancy of GATA1 and subsequently supporting transcription activation. Using a combination of CRISPR/CAS9-mediated genomic engineering and shRNA approaches we observed that depletion of either BRD2 or BRD4 alone blunted erythroid gene activation, while depletion of BRD3 only affected erythroid transcription in the setting of BRD2 deficiency. These results suggest that pharmacologic BET inhibition should be interpreted in the context of distinct steps in transcriptional activation and partially overlapping functions among BET family members. GATA1 null erythroblasts (G1E) conditionally expressing GATA1 as a GATA1-ER fusion protein were induced to express GATA1 by addition of 100nM estradiol for 24 hours. For GATA1 binding experiments this occurred in the absence or presence of 250nM JQ1. For BRD3 and BRD4 occupancy experiments G1E cells were compared to G1E cells with activated GATA1-ER fusion protein.
2015-02-23 | E-GEOD-62736 | biostudies-arrayexpress
Project description:Selective bromodomains inhibitors block the interaction between diverse bromodomains and extraterminal domains (BET) proteins and acetylated proteins. These inhibitors have shown beneficial effects in cancers malignancies and experimental inflammation in mouse models, but data on renal diseases are scarce. We have investigated the effect of the BET proteins inhibitor JQ1 in a mice model of unilateral ureteral obstruction. Treatment with JQ1 diminished renal damage, the presence of inflammatory cell infiltration and the upregulation of proinflammatory genes. The in vitro evaluation of JQ1 on TNF-α inducible genes in renal cells showed that BET inhibition modulated several biological processes, including inflammation or immune response. Moreover, gene-silencing experiments showed that BRD4 regulates several proinflammatory genes (IL-6, CCL-2 and CCL-5) and chromatin immunoprecipitation techniques demonstrated that BRD4 specifically binds to acetylated histone H3 in the promoter region of those genes. The nuclear factor-B (NF-B) pathway regulates renal inflammation. The RelA NF-B subunit is activated by acetylation of lysine 310. In damaged kidneys and in TNF-α-treated renal cells, JQ1 blocked the nuclear translocation of RelA/NF-B and NF-B-mediated gene expression. Additionally, obstructed kidneys showed an activation of the Th17 immune response, which was diminished by JQ1 treatment. Our results demonstrate that the BET inhibition decreases renal inflammation by 3 independent mechanisms: 1) chromatin remodelling in the promoter regions of specific genes, 2) blocking NF-B pathway activation, and 3) modulating the Th17 immune response. These results suggest that BET inhibitors could have important therapeutic applications in inflammatory renal diseases.
2016-07-01 | GSE71602 | GEO
Project description:In utero renal development is subject to maternal metabolic and environmental influences af-fecting long-term renal function and the risk to develop chronic kidney failure and cardiovascular disease. Epigenetic processes have been implicated in the orchestration of renal development and prenatal programming of nephron number. Bromodomain and extraterminal domain proteins act as histone acetylation reader molecules and promote gene transcription. BET family members Brd2, Brd3 and Brd4 are expressed in the nephrogenic zone during kidney development. Here, the effect of FDA-approved BET inhibitor JQ1 on renal development is evaluated. Inhibition of BET proteins via JQ1 leads to reduced growth of metanephric cultures, loss of the progenitor cell population, and premature and disturbed nephron differentiation.
2022-01-10 | GSE188453 | GEO
Project description:Triple negative breast cancer (TNBC) is a heterogeneous and clinically aggressive disease for which there is no targeted therapy. Here we report the preferential and high sensitivity of TNBCs to BET bromodomain inhibitors such as JQ1 manifested by cell cycle arrest in early G1, apoptosis, and induction of markers of luminal epithelial differentiation in vitro and in vivo. The sensitivity of TNBC and other tumor types to BET inhibition establishes a rationale for clinical investigation, and a motivation to understand mechanisms of resistance. After engendering acquired resistance to BET inhibition in previously sensitive TNBCs, we utilized integrative approaches to identify a unique mechanism of epigenomic resistance to this epigenetic therapy. Resistant cells remain dependent on BRD4, confirmed by RNA interference. However, TNBC cells adapt to BET bromodomain inhibition by re-recruitment of unmutated BRD4 to super-enhancers, now in a bromodomain-independent manner. Proteomic studies of resistant TNBC identify hyper-phosphorylation of BRD4 and strong association with MED1. Together, these studies provide a rationale for BET inhibition in TNBC and argue for combination strategies to anticipate clinical drug resistance. ChIP-seq in parental and JQ1 resistant triple negative breast cancer (TNBC) in response to DMSO or JQ1 treatment
2016-01-07 | E-GEOD-63581 | biostudies-arrayexpress
Project description:Disruptions of protein homeostasis in the endoplasmic reticulum (ER) elicit activation of the unfolded protein response (UPR), a translation- and transcription-coupled proteostatic stress response pathway. The primary translational control arm of the UPR is initiated by the PERK-dependent phosphorylation of eIF2α, leading to a large-scale reprogramming of translation and subsequent activation of an ATF4-mediated transcriptional program. It has remained challenging, however, to accurately evaluate the contribution of each component of the eIF2α/ATF4 pathway to the remodelling of transcription and translation. Here, we have used mouse embryonic fibroblasts containing either a knock-in of the non-phosphorylatable eIF2α S51A mutant or knock-out for ATF4 by ribosome profiling and mRNA-seq to define the specific contributions of eIF2α phosphoryation and ATF4 in controlling the translational and transcriptional components of the UPR. These studies show that the transcriptional and translational targets of each P-eIF2α, ATF4, and the other UPR gene expression programs overlapped extensively, leading to a core set of UPR genes whose robust expression in response to ER stress is driven by multiple mechanisms. The identification of other, more factor-specific targets illustrated the potential for functional specialization of the UPR. As the UPR progressed temporally, cells employed distinct combinations of transcriptional and translational mechanisms, initiated by different factors, to adapt to ongoing stress. These effects were accompanied by a buffering effect where changes in mRNA levels were coupled to opposing changes in ribosome loading, a property which makes cooperation between transcription and translation essential to confer robust protein expression. Translational analysis by ribosome profiling and mRNA-seq of PERK pathways mutants during the UPR. Mouse embryonic fibroblasts (MEFs) lacking components of the PERK pathway (eIF2a phosphorylation and ATF4) were subjected to ER stress and analyzed by ribosome profiling.
2016-07-03 | E-GEOD-68265 | biostudies-arrayexpress
Project description:Triple negative breast cancer (TNBC) is a heterogeneous and clinically aggressive disease for which there is no targeted therapy. Here we report the preferential and high sensitivity of TNBCs to BET bromodomain inhibitors such as JQ1 manifested by cell cycle arrest in early G1, apoptosis, and induction of markers of luminal epithelial differentiation in vitro and in vivo. The sensitivity of TNBC and other tumor types to BET inhibition establishes a rationale for clinical investigation, and a motivation to understand mechanisms of resistance. After engendering acquired resistance to BET inhibition in previously sensitive TNBCs, we utilized integrative approaches to identify a unique mechanism of epigenomic resistance to this epigenetic therapy. Resistant cells remain dependent on BRD4, confirmed by RNA interference. However, TNBC cells adapt to BET bromodomain inhibition by re-recruitment of unmutated BRD4 to super-enhancers, now in a bromodomain-independent manner. Proteomic studies of resistant TNBC identify hyper-phosphorylation of BRD4 and strong association with MED1. Together, these studies provide a rationale for BET inhibition in TNBC and argue for combination strategies to anticipate clinical drug resistance. RNA-Seq in parental and JQ1 resistant triple negative breast cancer (TNBC) in response to DMSO or JQ1 treatment over time
2016-01-07 | E-GEOD-63582 | biostudies-arrayexpress
Project description:Background: Neurofibromatosis type 2 (NF2) is an autosomal dominant genetic disease characterized by the development of multiple Schwannomas, usually occurring on both VIIIth (vestibular) cranial nerves. Bromodomain and extra-terminal domain (BET) proteins regulate gene transcription and their activity is required in a variety of cancers including malignant peripheral nerve sheath tumors (MPNST). The use of BET inhibitors as a therapeutic option to treat NF2 schwannomas has not been explored and is the focus of this study. Methods: A panel of normal and NF2-null Schwann cell and schwannoma cell lines were used to characterize the impact of the BET inhibitor JQ1 in vitro and in vivo. The mechanism of action was explored by chromatin immunoprecipitation (ChIP) of the BET BRD4, phospho-kinase arrays and immunohistochemistry of BRD4 in human vestibular schwannomas. Results: JQ1 inhibited the proliferation of NF2-null schwannoma and Schwann cell lines in vitro and in vivo. Further, loss of NF2 by CRISPR deletion or siRNA knockdown increased the sensitivity of cells to JQ1. Knock-down experiments identified BRD4 as the BET family member mediating the majority of JQ1 effects on cell proliferation. Immunohistochemistry demonstrated elevated levels of BRD4 protein in human vestibular schwannomas. BRD4 ChIP experiments identified the small G-protein Rac1 and PI3K signaling pathways as sensitive to JQ1. Conclusions: NF2 deficient Schwann cell and schwannoma cells are sensitive to BET inhibition, primarily mediated by BRD4, which is overexpressed in human vestibular schwannomas. BRD4 regulates Rac/Ras and PI3K signaling pathways and inhibition of these pathways by JQ1 impedes NF2 Schwannoma growth. These findings implicate BET inhibition as a therapeutic option for NF2-deficient schwannomas.
2022-08-02 | GSE167560 | GEO
Project description:Triple negative breast cancer (TNBC) is a heterogeneous and clinically aggressive disease for which there is no targeted therapy. Here we report the preferential and high sensitivity of TNBCs to BET bromodomain inhibitors such as JQ1 manifested by cell cycle arrest in early G1, apoptosis, and induction of markers of luminal epithelial differentiation in vitro and in vivo. The sensitivity of TNBC and other tumor types to BET inhibition establishes a rationale for clinical investigation, and a motivation to understand mechanisms of resistance. After engendering acquired resistance to BET inhibition in previously sensitive TNBCs, we utilized integrative approaches to identify a unique mechanism of epigenomic resistance to this epigenetic therapy. Resistant cells remain dependent on BRD4, confirmed by RNA interference. However, TNBC cells adapt to BET bromodomain inhibition by re-recruitment of unmutated BRD4 to super-enhancers, now in a bromodomain-independent manner. Proteomic studies of resistant TNBC identify hyper-phosphorylation of BRD4 and strong association with MED1. Together, these studies provide a rationale for BET inhibition in TNBC and argue for combination strategies to anticipate clinical drug resistance. Chem-Seq in parental and JQ1 resistant triple negative breast cancer (TNBC)
2016-01-07 | E-GEOD-63284 | biostudies-arrayexpress
Project description:Men who develop metastatic castration-resistant prostate cancer (CRPC) invariably succumb to the disease. The development and progression to CRPC following androgen ablation therapy is predominantly driven by unregulated androgen receptor (AR) signaling1-3. Despite the success of recently approved therapies targeting AR signaling such as abiraterone4-6 and second generation anti-androgens MDV3100 (enzalutamide)7,8, durable responses are limited, presumably due to acquired resistance. Recently JQ1 and I-BET, two selective small molecule inhibitors that target the amino-terminal bromodomains of BRD4, have been shown to exhibit antiproliferative effects in a range of malignancies9-12. Here we show that AR signaling-competent CRPC cell lines are preferentially sensitive to BET bromodomain inhibition. BRD4 physically interacts with the N-terminal domain of AR and can be disrupted by JQ111,13. Like the direct AR antagonist, MDV3100, JQ1 disrupted AR recruitment to target gene loci. In contrast to MDV3100, JQ1 functions downstream of AR, and more potently abrogated BRD4 localization to AR target loci and AR mediated gene transcription including induction of TMPRSS2-ERG and its oncogenic activity. In vivo, BET bromodomain inhibition was more efficacious than direct AR antagonism in CRPC xenograft models. Taken together, these studies provide a novel epigenetic approach for the concerted blockade of oncogenic drivers in advanced prostate cancer. Examination of AR, BRD2, BRD3, BRD4, ERG, RNA Pol II and H3K27ac in prostate cancer cells with respect to BET inhibitors
2014-04-25 | E-GEOD-55062 | biostudies-arrayexpress