Search Results (160)

Background/Objectives: Parkinson’s disease (PD) is one of the most prevalent neurodegenerative disorders. Despite its multifactorial etiology, PD pathophysiology shared specific features such as cytoplasmic α-synuclein inclusions, oxidative stress, mitochondrial dysfunction, and impaired autophagy. Bromodomain and Extra-Terminal domain (BET) proteins, functioning as epigenetic readers, have recently emerged as promising therapeutic targets due to their regulatory role in redox homeostasis, neuroinflammation, and autophagy. However, their potential involvement in PD pathophysiology remains largely unexplored. Therefore, we aimed at evaluating whether BET modulation could ameliorate the parkinsonian phenotype in two cellular models. Methods: Differentiated SH-SY5Y and N1E-115 neuronal cells were exposed to rotenone toxin to mimic PD phenotype and co-treated with the small BET inhibitor JQ1. Results: BET inhibition significantly counteracted rotenone-induced cell death, neuromorphological alterations, and α-synuclein accumulation. These protective effects were accompanied by restoration of redox balance, as indicated by enhanced activation of the antioxidant system and suppression of the pro-oxidant NADPH oxidase complex. Moreover, JQ1 treatment alleviated mitochondrial dysfunction and corrected autophagy impairments triggered by rotenone. Conclusions: These data highlight a novel role for BET proteins in neurodegeneration, suggesting that their modulation may represent a promising approach to counteract PD neuropathology. Full article

Inflammation underpins pulmonary disease progression during tobacco smoke exposure, which may culminate in irreversible pulmonary disease. While primary smoke poses a notable risk, nearly half of the US population is also susceptible due to frequent exposure to secondhand smoke (SHS). In the present study, we assessed the potential role of VYN202, a novel small molecular bromodomain and extra-terminal inhibitor, as a possible means of attenuating SHS-mediated inflammation. We exposed wild-type mice to an acute time course of room air (RA), SHS via a nose-only delivery system (Scireq Scientific, Montreal, Canada), or to both SHS and 10 mg/kg VYN202 (efficacious dose from prior inflammatory models) via oral gavage three times a week. Specific smoke exposure delivery to mice involved SHS from two cigarettes over 10 min, equilibration in room air for 10 min, followed by exposure to SHS from one cigarette for an additional 10 min, for a total SHS exposure of 20 min per day, five days a week for 30 days. We evaluated leukocyte abundance and the secretion of inflammatory mediators in bronchoalveolar lavage fluid (BALF). We also assessed general morphology via histology staining and the activation of receptor tyrosine kinase (RTK) family members. While standard hematoxylin and eosin (H&E) staining resulted in unchanged morphology, SHS-mediated increases in BALF protein abundance, total cellularity, and percent PMNs were attenuated with concomitant administration of VYN202. We also discovered SHS-induced activation of RTKs that were pro-inflammatory (JAK1, JAK3, ABL1, and ACK1), as well as RTKs related to endothelial and vascular remodeling (VEGFR3, VEGFR2, EphB4, EphB6, and FAK). Furthermore, inflammatory cytokines including GCSF, IFN-γ, IL-12p70, IL-17A, LIX, and TNF-α were all augmented by SHS exposure. Despite SHS exposure, each of these RTKs and cytokines/chemokines was significantly attenuated by VYN202. In summary, inflammatory responses induced by SHS exposure were mitigated by VYN202. These data reveal fascinating potential for the utility of VYN202 in lessening smoke-induced pulmonary exacerbations. Full article

Uterine Fibroids (UFs) are the most common benign tumors in women of reproductive age, affecting ~77% of women overall and are clinically manifest in ~25% by age 50. Bromodomain and extra-terminal domain (BET) proteins play key roles in epigenetic transcriptional regulation, influencing many biological processes, such as proliferation, differentiation, and DNA damage response. Although BET dysregulation contributes to various diseases, their specific role in the pathogenesis of UFs remains largely unexplored. The present study aimed to determine the expression pattern of BET proteins in UFs and matched myometrium and further assess the impact of BET inhibitors on UF phenotype and epigenetic changes. Our studies demonstrated that the levels of Bromodomain-containing protein (BRD)2 and detection rate of BRD4 were significantly altered in UFs compared to matched myometrium, suggesting that aberrant BET protein expression may contribute to the pathogenesis of UFs. To investigate the biological effects of BET proteins, two small-molecule inhibitors, JQ1 and I-BET762, were used to assess their impact on UF cell behavior and transcriptomic profiles. Targeted inhibition of BET proteins markedly reduced UF cell viability compared with myometrial cells and induced cell cycle arrest. Unbiased transcriptomic profiling coupled with bioinformatic analysis revealed that BET inhibition altered multiple biological pathways, including G2M checkpoint, E2F targets, mitotic spindle, mTORC1 signaling, TNF-α signaling via NF-κB, and inflammatory response, as well as reprogrammed the UF cell epigenome. Notably, BET inhibition decreased the expression of several genes encoding extracellular matrix (ECM) proteins, a hallmark of UFs. Collectively, these results support that BET proteins play a pivotal role in regulating key signaling pathways and cellular processes in UFs. Targeting BET proteins may therefore represent a promising non-hormonal therapeutic strategy for UF treatment. Full article

Bromodomain and extraterminal domain (BET) proteins act as epigenetic regulators of gene transcription. BET inhibitors have shown therapeutic potential in various models of heart failure; however, their efficacy in atrial fibrillation (AF) remains incompletely understood. This study investigated the effects of the BET inhibitor JQ1 in a mice model of AF. Wild-type male C57BL/6 mice were randomized into four groups: control, JQ1 alone (50 mg/kg, intraperitoneal), angiotensin II (AngII; 1 μg/kg/min), and AngII plus JQ1. After 2 weeks, electrophysiological studies revealed that JQ1 significantly reduced AngII-induced AF inducibility and duration. It also attenuated left atrial enlargement, diastolic dysfunction, and cardiac fibrosis. Molecular analyses indicated that JQ1 suppressed the AngII-induced upregulation of pro-fibrotic genes and restored Sirt1 expression. Moreover, JQ1 also inhibited AngII-enhanced oxidized CaMKII and phosphorylated RyR2 levels. In HL-1 atrial cardiomyocytes, JQ1 improved calcium handling abnormalities, shortened prolonged action potential duration (APD), and restored mitochondrial respiration and adenosine triphosphate (ATP) production, all of which had been impaired by AngII. These findings suggest that BET inhibition by JQ1 mitigates structural and electrical remodeling associated with AF by attenuating atrial fibrosis, and by restoring calcium homeostasis, mitochondrial function, and Sirt1 expression. JQ1 may represent a novel therapeutic strategy for the prevention and treatment of AF. Full article

ATPase family AAA domain-containing protein 2 (ATAD2) has been recognized as a key oncogene that regulates chromatin remodeling, transcription, and cancer progression. As a member of the bromodomain (BRD) family, ATAD2 plays a crucial role in epigenetic modifications and is associated with multiple malignancies. Despite being considered an undruggable target in the past, crystallography and computational modeling have significantly accelerated ATAD2 drug discovery and development. This review provides a comprehensive overview of the structural features, functional roles, and biological significance of ATAD2, particularly in the context of cancer. We present an in-depth overview of different molecular strategies reported in the literature to suppress ATAD2 expression, including genetic and pharmacological approaches, and discuss their mechanistic and therapeutic implications. Particular emphasis is given to recent efforts in developing small-molecule inhibitors, detailing their binding interactions, therapeutic potential, and challenges in clinical translation. In addition, we performed alanine scanning calculations on molecular dynamics (MD)-simulated trajectories derived from protein–ligand complexes based on X-ray co-crystal structures containing three distinct ligands with different binding modes. This analysis provided critical insights into the binding interface of BRD-ATAD2, enhancing our understanding of its ligand interactions. Furthermore, we examine the emerging roles of ATAD2 in mediating resistance to cancer therapies, underscoring its potential as a target for overcoming drug resistance. By integrating structural insights, mechanistic studies, drug discovery efforts, and the challenges of developing ATAD2-targeted cancer therapies, this review emphasizes the need for further research to optimize ATAD2 inhibition strategies and explore its full therapeutic potential in oncology. Full article

Smooth muscle cell (SMC) differentiation plays a crucial role in angiogenesis and vasculogenesis during embryonic development. The underlying mechanisms controlling SMC differentiation, especially progenitor-specific regulation, however, remain largely unclear. In this study, we identified bromodomain-containing protein 4 (BRD4) as a novel regulator for SMC differentiation. Transforming growth factor-β (TGF-β) induces BRD4 expression in the initial phase of SMC differentiation of pluripotent murine 10T1/2 cells. BRD4 was found critical in mediating TGF-β-induced SMC differentiation. Knockdown of BRD4 with siRNA suppressed TGF-β-induced expression of SMC markers including α-SMA and SM22α. In addition, the BRD4 inhibitor JQ1 and degraders ARV-825 and dBET1 suppressed TGF-β-induced SMC marker gene expression. BRD4 regulates SMC differentiation by activating SMC marker gene transcription. BRD4 mediated SMC differentiation is independent of the phosphorylation of Smad2/3. Instead, BRD4 mediated TAZ expression induced by TGF-β. Consistent with the function of TAZ, the inhibition of BRD4 reduced nuclear retention of Smad3, thereby impairing Smad3 mediated SMC gene transcription. Myocardin is an important transcriptional modulator for SMC markers. Interestingly, the knockdown of BRD4 also attenuated the induction of myocardin due to TGF-β in 10T1/2 cells. Taken together, this study demonstrates that BRD4 is a novel modulator for SMC differentiation from mesenchymal progenitor cells through the regulation of TAZ and myocardin. Full article

Background: Malaria remains a significant global health burden, particularly in sub-Saharan Africa, accounting for high rates of illness and death. The growing resistance to frontline antimalarial therapies underscores the urgent need for novel drug targets and therapeutics. Bromodomain-containing proteins, which regulate gene expression through chromatin remodeling, have gained attention as potential targets. Plasmodium falciparum bromodomain protein 1 (PfBDP1), a 55 kDa nuclear protein, plays a key role in recognizing acetylated lysine residues and facilitating transcription during parasite development. Methods: This study investigated ex vivo PfBDP1 gene mutations and identified potential small molecule inhibitors using computational approaches. Malaria-positive blood samples were collected. Genomic DNA was extracted, assessed for quality, and amplified using PfBDP1-specific primers. DNA sequencing and alignment were performed to determine single-nucleotide polymorphism (SNP). Structural modeling used the PfBDP1 crystal structure (PDB ID: 7M97), and active site identification was conducted using CASTp 3.0. Virtual screening and pharmacophore modeling were performed using Pharmit and AutoDock Vina, followed by ADME/toxicity evaluations with SwissADME, OSIRIS, and Discovery Studio. GROMACS was used for 100 ns molecular dynamics simulations. Results: The malaria prevalence rate stood at 12.24%, and the sample size was 165. Sequencing results revealed conserved PfBDP1 gene sequences compared to the 3D7 reference strain. Virtual screening identified nine lead compounds with binding affinities ranging from −9.8 to −10.7 kcal/mol. Of these, CHEMBL2216838 had a binding affinity of −9.9 kcal/mol, with post-screening predictions of favorable drug-likeness (8.60), a high drug score (0.78), superior pharmacokinetics, and a low toxicity profile compared to chloroquine. Molecular dynamics simulations confirmed its stable interaction within the PfBDP1 active site. Conclusions: Overall, this study makes a significant contribution to the ongoing search for novel antimalarial drug targets by providing both molecular and computational evidence for PfBDP1 as a promising therapeutic target. The prediction of CHEMBL2216838 as a lead compound with favorable binding affinity, drug-likeness, and safety profile, surpassing those of existing drugs like chloroquine, sets the stage for preclinical validation and further structure-based drug design efforts. These findings are supported by prior experimental evidence showing significant parasite inhibition and gene suppression capability of predicted hits. Full article

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi (T. cruzi), continues to pose significant public health challenges due to the toxicity, poor tolerability, and limited efficacy of current treatments. Targeted protein degradation (TPD) using proteolysis-targeting chimeras (PROTACs) represents a novel therapeutic avenue by leveraging the ubiquitin–proteasome system to selectively degrade essential parasite proteins. This review introduces the conceptual framework of “TrypPROTACs” as a prospective strategy for T. cruzi, integrating a comprehensive analysis of druggable targets across critical biological pathways, including ergosterol biosynthesis, redox metabolism, glycolysis, nucleotide synthesis, protein kinases, molecular chaperones such as heat shock protein 90 (Hsp90), and epigenetic regulators such as T. cruzi bromodomain factor 3 (TcBDF3). It is important to note that no TrypPROTAC compound has yet been synthesized or experimentally validated in T. cruzi; the approach discussed herein remains theoretical and forward-looking. Representative inhibitors for each target class are compiled, highlighting potency, selectivity, and structural features relevant to ligand design. We also examine the parasite’s ubiquitination machinery and compare it to the human system to identify putative E3 ubiquitin ligases. Key aspects of linker engineering and ternary complex stabilization are discussed, alongside potential validation techniques such as the cellular thermal shift assay (CETSA) and bioluminescence resonance energy transfer (NanoBRET). Collectively, these insights outline a roadmap for the rational design of TrypPROTACs and support the feasibility of expanding targeted protein degradation strategies to neglected tropical diseases. Full article

Defects in lysosomal cholesterol handling provoke fatal disorders presenting neurovisceral symptoms with variable onset and life spans. A prime example is Niemann–Pick type C disease (NPCD), where cholesterol export from the endosomal–lysosomal system is impaired due to variants of either NPC intracellular cholesterol transporter 1 (NPC1) or NPC intracellular cholesterol transporter 2 (NPC2). Therapeutic options for NPCD are limited to palliative care and disease-modifying drugs, and there is a need for new treatments. Here, we explored bromodomain and extra-terminal domain (BET) proteins as new drug targets for NPCD using patient-derived skin fibroblasts. Treatment with JQ1, a prototype BET protein inhibitor, raised the level of NPC1 protein, diminished lysosomal expansion and cholesterol accumulation, and induced extracellular release of lysosomal components in a dose-, time-, and patient-dependent manner. Lastly, JQ1 enhanced and reduced cholesterol accumulation induced by pharmacologic inhibition of NPC1 and of histone deacetylase (HDAC) activity, respectively. Taken together, bromodomain proteins should be further explored as therapeutic drug targets for lysosomal diseases like NPCD, and as new components regulating lysosomal function and cholesterol metabolism. Full article

Background: Myeloid-derived suppressor cells (MDSCs) contribute to immune suppression observed in chronic lymphocytic leukemia (CLL). MDSCs are immature myeloid cells that are hijacked during development and further reprogrammed by the tumor microenvironment (TME) to harbor immune-suppressive properties and inhibit T-cell functions. Bromodomain and extraterminal domain (BET) proteins, including BRD4, are epigenetic modulators that regulate genes implicated in CLL pathogenesis and TME interactions. Previously, we investigated how the novel BET inhibitor OPN-51107 (OPN5) prevents CLL disease expansion, modulates T-cell immune function, and alters gene expression related to MDSCs. In turn, we hypothesize that BET proteins such as BRD4 regulate MDSC functions, and subsequent pharmacological inhibition of BRD4 will alleviate MDSC-mediated immune suppression in CLL. Methods: Utilizing the Eµ-TCL1 mouse model of CLL, we evaluated BRD4 protein expression in MDSCs derived from the bone marrow of transgenic and age-matched wild-type (WT) mice. We then investigated the ex vivo functionality of OPN5-treated MDSCs, expanded from Eµ-TCL1 and WT bone marrow in MDSC-supportive medium. Finally, we conducted an in vivo study utilizing the Eµ-TCL1 adoptive transfer mouse model to determine the in vivo effects of OPN5 on MDSCs and other immune populations. Results: Through the course of this study, we found that MDSCs isolated from Eμ-TCL1 mice upregulate BRD4 expression and are more immune-suppressive than their WT counterparts. Furthermore, we demonstrated ex vivo OPN5 treatment reverses the immune-suppressive capacity of MDSCs isolated from leukemic mice, evident via enhanced T-cell proliferation and IFNγ production. Finally, we showed in vivo OPN5 treatment slows CLL disease progression and modulates immune cell populations, including MDSCs. Conclusions: Altogether, these data support BET inhibition as a useful therapeutic approach to reverse MDSC-mediated immune suppression in CLL. Full article

Childhood neuroblastoma (NB) is a malignant tumour that is a member of a class of embryonic tumours that have their origins in sympathoadrenal progenitor cells. There are five stages in the clinical NB staging system: 1, 2A, 2B, 3, 4S, and 4. For those diagnosed with stage 4 neuroblastoma (NBS4), the treatment options are limited with a survival rate of between 40 and 50%. Since 1975, more than 15 targets have been identified in the search for a treatment for high-risk NBS4. This article is concerned with the search for a multi-target drug treatment for high-risk NBS4 and focuses on four possible treatment targets that research has identified as having a role in the development of NBS4 and includes the inhibitors Histone Deacetylase (HDAC), Bromodomain (BRD), Hedgehog (HH), and Tropomyosin Kinase (TRK). Computer-aided drug design and molecular modelling have greatly assisted drug discovery in medicinal chemistry. Computational methods such as molecular docking, homology modelling, molecular dynamics, and quantitative structure–activity relationships (QSAR) are frequently used as part of the process for finding new therapeutic drug targets. Relying on these techniques, the authors describe a medicinal chemistry strategy that successfully identified eight compounds (inhibitors) that were thought to be potential inhibitors for each of the four targets listed above. Results revealed that all four targets BRD, HDAC, HH and TRK receptors binding sites share similar amino acid sequencing that ranges from 80 to 100%, offering the possibility of further testing for multi-target drug use. Two additional targets were also tested as part of this work, Retinoic Acid (RA) and c-Src (Csk), which showed similarity (of the binding pocket) across their receptors of 80–100% but lower than 80% for the other four targets. The work for these two targets is the subject of a paper currently in progress. Full article

Background/Objectives: Metastatic prostate cancer (PCa) remains a major clinical challenge with limited therapeutic options. The long non-coding RNA H19 has been implicated in regulating cell adhesion molecules and collective migration, key features of metastatic dissemination. This study investigates the role of the Bromodomain and Extra-Terminal (BET) proteins BRD2, BRD3, and BRD4 in the H19-dependent transcriptional regulation of cell adhesion molecules. Currently, the major effects of BET inhibitors require androgen receptor (AR) expression. Methods: H19 was stably silenced in PC-3 (AR-null) and 22Rv1 (AR-positive) castration-resistant PCa cells. The cells were treated with the pan-BET inhibitors JQ1 and OTX015 or the BET degrader dBET6. In vivo, the effects of JQ1 were evaluated in xenograft mouse models. Chromatin immunoprecipitation (ChIP) and RNA-ChIP were used to assess BET protein recruitment and interaction with cell adhesion gene loci and H19. Organotypic slice cultures (OSCs) from fresh PCa surgical specimens were used as ex vivo models to validate transcriptional changes and BRD4 recruitment. Results: BET inhibition significantly reduced the expression of β4 integrin and E-cadherin and cell proliferation in both basal conditions, and following H19 knockdown in PC-3 and 22Rv1 cells. These effects were mirrored in JQ1-treated tumor xenografts, which showed marker downregulation and tumor regression. ChIP assays revealed that BRD4, more than BRD2/3, was enriched on β4 integrin and E-cadherin promoters, especially in regions marked by H3K27ac. H19 silencing markedly enhanced BRD4 promoter occupancy. RNA-ChIP confirmed a specific interaction between BRD4 and H19. These findings were validated in OSCs, reinforcing their clinical relevance. Conclusions: Our study demonstrates that BRD4 epigenetically regulates the H19-mediated transcriptional control of adhesion molecules involved in collective migration and metastatic dissemination. Importantly, these effects are independent of AR status, suggesting that targeting the H19/BRD4 axis may represent a promising therapeutic avenue for advanced PCa. Full article

Background/Objectives: Human glioblastoma (GBM) is the most aggressive brain cancer in adults and a highly treatment-refractory malignancy. The overall prognosis for the GBM is extremely poor, with a median survival of 12–14 months after initial diagnosis. Many GBM patients initially respond to the DNA alkylating agent temozolomide (TMZ), but patients often become therapy-resistant, and tumors recur. We previously reported that treatment with PFI-3, which is a small molecule inhibitor of the bromodomain of the BRG1 subunit of the SW1/SNF chromatin remodeling complex, enhanced the sensitivity of GBM cells to TMZ in vitro and in vivo GBM animal models. Our general objective was to perform an SAR study of new diphenyl PFI-3 analogs. Methods: New structural analogs of PFI-3 were developed, synthesized, and tested for their ability to enhance TMZ-induced GBM cell death by ELISA. Results: Following on the enhanced activity of compounds 2a and 2b, new diphenyl PFI-3 analogs with specific structural adjustments were made to better understand the structural requirements to optimize function. Additionally, several new structurally different candidates (e.g., 4a, 4b, and 5) showed much better efficacy in sensitizing GBM cells to TMZ-induced GBM cell death. Conclusions: Four series of PFI-3 analogs (2, 3, 4, and 5) were designed, synthesized, and tested for the ability to sensitize GBM cells to TMZ-induced cell death. Series 2 optimized the A-ring and R-isomer chirality. Series 3 used a 5-membered linker with weak activity. Series 4’s di-phenyl urea compounds showed better bromodomain inhibition. Series 5’s methoxyphenyl-B-ring analogs were exceptionally strong inhibitors. Full article

Background: Dynamic changes in histone acetylation play crucial roles during cellular differentiation and disease development, but their detection in living cells is still a challenging task. Objectives: Here, we developed a Bimolecular Anchor Detector (BiAD) sensor for the detection of locus-specific changes in histone acetylation in living cells by fluorescence microscopy. Methods: We used the BRD9 bromodomain cloned as tandem double domain (2xBRD9-BD) as a reader of histone acetylation. It was integrated into a dual-color BiAD chassis that was previously described by us. Results: We identified the gene body of TTC34 as a potential target for our sensor, because it contains dense histone acetylation and 392 local sequence repeats. Using a binding-deficient mutant of 2xBRD9-BD as a negative control, we established a successful readout of histone acetylation at the TTC34 locus. A single-domain reader did not function, indicating the requirement for the double reader to enhance the affinity and specificity of the chromatin interaction via avidity effects. With this sensor, we could detect dynamic increases in histone acetylation at the TTC34 locus after the treatment of cells with the histone deacetylase inhibitor Trichostatin A for 6 h indicating the applicability of the sensor for single-cell epigenome studies. Conclusions: Our data demonstrate that active chromatin modifications can be detected by BiAD sensors using 2xBRD9-BD as a reader. This complements the toolkit of the available BiAD sensors and documents the modularity of BiAD sensors. Full article

Salivary gland dysfunction is a hallmark of Sjögren’s disease (SjD). Here, we investigated the pro-inflammatory properties of salivary gland-derived fibroblasts (SGF) that were cultured from minor salivary gland (MSG) tissues of patients with SjD and controls. SGF from patients with SjD exhibited higher rates of proliferation compared to controls. RNA sequencing revealed pronounced pro-inflammatory properties of SGF in response to stimulation with IL1 and polyI:C, with an activation of “interferon responses”, “JAK STAT”, and “NF-kappa B” signaling, as well as ”complement” pathways. In addition to encoding pro-inflammatory transcripts, stimulated SGF featured increased expression of a number of non-coding enhancer RNAs (eRNAs) that we originally identified in TNF-stimulated synovial fibroblasts (FLS) by CAGE sequencing. We confirmed the expression of selected eRNAs in SGF and FLS through time-course experiments upon stimulation with different pro-inflammatory stimuli using real-time PCR. Furthermore, we detected eRNAs for IL6 (eIL6) and IL8 (eIL8#3) in MSG tissues. Treatment of SGF with the bromodomain inhibitor I-BET suppressed IL1- and LPS-induced expression of all eRNAs tested, as well as their associated pro-inflammatory coding transcripts. Transfection of SGF with antisense nucleotides targeting eCCL20 reduced the LPS-induced expression of this eRNA, as well as CCL20 expression and secretion. Together, our data highlight similarities between SGF and FLS regarding their activation under inflammatory conditions. Full article