Search Results (35)

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

Fibrosis represents a pivotal pathological process in numerous diseases, characterized by excessive deposition of extracellular matrix (ECM) that disrupts normal tissue architecture and function. In the heart, cardiac fibrosis significantly impairs both structural integrity and functional capacity, contributing to the progression of heart failure. Central to this process are cardiac fibroblasts (CFs), which, upon activation, differentiate into contractile myofibroblasts, driving pathological ECM accumulation. Transforming growth factor-beta (TGFβ) is a well-established regulator of fibroblast activation; however, the precise molecular mechanisms, particularly the involvement of ion channels, remain poorly understood. Emerging evidence highlights the regulatory role of ion channels, including calcium-activated potassium (K_Ca) channels, in fibroblast activation. This study elucidates the role of ion channels and investigates the mechanism by which Yoda1, an agonist of the mechanosensitive ion channel Piezo1, modulates TGFβ-induced fibroblast activation. Using NIH/3T3 fibroblasts, we demonstrated that TGFβ-induced activation is regulated by tetraethylammonium (TEA)-sensitive potassium channels, but not by specific K⁺ channel subtypes such as BK, SK, or IK channels. Intriguingly, Yoda1 was found to inhibit TGFβ-induced fibroblast activation through a Piezo1-independent mechanism. Transcriptomic analysis revealed that Yoda1 modulates fibroblast activation by altering gene expression pathways associated with fibrotic processes. Bromodomain-containing protein 4 (BRD4) was identified as a critical mediator of Yoda1’s effects, as pharmacological inhibition of BRD4 with JQ1 or ZL0454 suppressed TGFβ-induced expression of the fibroblast activation marker Periostin (Postn). Conversely, BRD4 overexpression attenuated the inhibitory effects of Yoda1 in both mouse and rat CFs. These results provide novel insights into the pharmacological modulation of TGFβ-induced cardiac fibroblast activation and highlight promising therapeutic targets for the treatment of fibrosis-related cardiac pathologies. Full article

Searching for new anticancer drugs is a significant challenge for the medical community due to the current limitations of existing treatments. The primary objective of this study was to design and optimize multi-targeted drug candidates based on a quinoline scaffold. In this paper, we adopt various in silico techniques, including molecular docking, molecular dynamics simulations, and ADMET property modeling, to predict the binding affinity and interactions of 7-ethyl-10-hydroxycamptothecin derivatives with multiple biological targets. The interactions of these compounds with three potential molecular targets, topoisomerase I, bromodomain-containing protein 4, and ATP-binding cassette sub-family G member 2 proteins, were analyzed. It has been previously proved that the inhibition of these molecular targets may have beneficial effects on cancer treatment. The designed chemical compounds can effectively interact with selected proteins, thereby establishing their potential as drug candidates. Molecular docking revealed promising binding affinities, with topoisomerase I docking scores ranging from −9.0 to −10.3 kcal/mol, BRD4 scores from −6.6 to −8.0 kcal/mol, and ABCG2 scores from −8.0 to −10.0 kcal/mol. Furthermore, the ADMET property analysis indicates promising pharmacological profiles, protein binding affinity, selectivity, and bioavailability while minimizing toxicity. For example, satisfactory logP values have been demonstrated in the favorable range for bioavailability after oral administration. Additionally, several compounds exhibited predicted aqueous solubility values greater than −3, suggesting moderate-to-good solubility, which is crucial for oral drug delivery. Full article

Cadmium (Cd) is a toxic heavy metal that threatens public health, with kidney injury being one of the common manifestations after Cd exposure. Oxidative stress plays a crucial role in Cd-induced kidney injury, arising from an imbalance between cellular oxidation and antioxidation processes. Bromodomain-containing protein 4 (BRD4) has been identified as a significant factor in the initiation and advancement of multiple diseases, primarily due to its regulatory role in oxidative stress. Nevertheless, the specific role of BRD4 in Cd-induced kidney oxidative injury remains poorly understood. The present study demonstrates that BRD4 is activated in the kidney after Cd exposure, while JQ1 (a BRD4 inhibitor) treatment inhibits Cd-induced oxidative stress and kidney injury. Subsequently, we investigate the mechanisms by which Cd regulates oxidative stress both in vivo and in vitro. The results indicate that JQ1 treatment reduces the expression levels of NADPH oxidase 4 (Nox4), thereby alleviating mitochondrial damage and reducing reactive oxygen species (ROS) generation. Furthermore, JQ1 treatment facilitates nuclear translocation levels of Nuclear factor erythroid-derived 2-like 2 (Nrf2), thereby enhancing the antioxidant defense system in the kidney after Cd exposure. In conclusion, this study reveals that BRD4 is significantly involved in the process of Cd-induced oxidative damage in the kidney, while inhibiting BRD4 is observed to attenuate ROS generation by regulating Nox4 and enhance ROS scavenging by regulating Nrf2, which, in turn, suppresses the oxidative stress level in the kidney after Cd exposure. These findings suggest that targeting BRD4 may represent an effective strategy for the prevention and treatment of Cd-induced kidney diseases. Full article

The liver is a pioneer internal organ that orchestrates major metabolic, detoxification, and endocrine roles. Acute factors like hepatitis and drug allergy and chronic causes like metabolic dysfunction-associated fatty liver disease (MASLD) and Hepatocellular carcinoma (HCC) drive hepatic wellness imbalances. Liver fibrosis is a reversible and curable anomaly, but the limited availability of safe and higher-specificity therapeutics is a challenging quest in hepatology. This study investigates the hepato-protective effect of Phyllanthus niruri compounds against liver fibrosis targets like lysyl oxidase-like 2 (LOXL2), heat shock protein 47 (HSP47), bromodomain-containing protein 4 (BRD4) and inhibitory kappa B kinase beta (IKKβ) and compare their anti-hepatic fibrosis activity against known inhibitors. Potential plant compounds from P. niruri were retrieved from the literature repositories, and the top 35 compounds were screened based on molecular weight, Lipinski’s rule of 5, and bioavailability score. The in silico molecular docking and in silico ADMET results provide valuable insights into hit compounds of P. niruri, namely quercitrin and hinokinin, to have good binding scores (BE) below −7 kcal/mol threshold and molecular interactions with many key residues of all the four liver fibrosis targets namely the BRD4, HSP47, LOLX2, and IKKB proteins explored in this research. Quercitrin has been identified to have BE values of −8.1, −8.3, −8.2, and −9.1 kcal/mol scores against the BRD4, HSP47, LOLX2, and IKKB proteins, respectively. Similarly, hinokinin also shows BE values of −8.8, −7.4, −6.7, and −9.0 kcal/mol scores with BRD4, HSP47, LOLX2, and IKKB proteins individually. Further, in vitro and animal model-based in vivo experimental analysis needs to be explored to validate the potential of quercitrin and hinokinin for anti-liver fibrosis in the future. Full article

Experimental evidence suggests that, in the inflamed gut of inflammatory bowel disease (IBD) patients, interleukin-34 (IL-34) triggers detrimental signaling pathways. Factors/mechanisms regulating IL-34 production in IBD remain poorly characterized. Bromodomain-containing 4 (BRD4), a transcriptional and epigenetic regulator, is over-expressed in IBD, and studies in cancer cells suggest that BRD4 might positively control IL-34 expression. This study aimed to assess whether, in IBD, BRD4 regulates IL-34 expression. In IBD, there was an up-regulation of both IL-34 and BRD4 compared to the controls, and the two proteins co-localized in both lamina propria mononuclear cells (LPMCs) and epithelial cells. Flow cytometry analysis of CD45+ LPMCs confirmed that the percentages of IL-34- and BRD4-co-expressing cells were significantly higher in IBD than in the controls and showed that more than 80% of the IL-34-positive CD45-LPMCs expressed BRD4. IL-34 and BRD4 were mainly expressed by T cells and macrophages. IL-34 expression was reduced in IBD LPMCs transfected with BRD4 antisense oligonucleotide and in the colons of mice with dextran sulfate sodium-induced colitis treated with JQ1, a pharmacological inhibitor of BRD4. These data indicate that BRD4 is a positive regulator of IL-34 in IBD, further supporting the pathogenic role of BRD4 in IBD-associated mucosal inflammation. Full article

A 3D structure-based pharmacophore model built for bromodomain-containing protein 4 (BRD4) is reported here, specifically developed for investigating and identifying the key structural features of the (+)-JQ1 known inhibitor within the BRD4 binding site. Using this pharmacophore model, 273 synthesized and purchased compounds previously considered for other targets but yielding poor results were screened in a drug repositioning campaign. Subsequently, only six compounds showed potential as BRD4 binders and were subjected to further biophysical and biochemical assays. Compounds 2, 5, and 6 showed high affinity for BRD4, with IC₅₀ values of 0.60 ± 0.25 µM, 3.46 ± 1.22 µM, and 4.66 ± 0.52 µM, respectively. Additionally, these compounds were tested against two other bromodomains, BRD3 and BRD9, and two of them showed high selectivity for BRD4. The reported 3D structure-based pharmacophore model proves to be a straightforward and useful tool for selecting novel BRD4 ligands. Full article

This study investigates the use of camel milk-derived exosomes (CMEs) as carriers for ARV-825, an anticancer agent targeting bromodomain-containing protein 4 (BRD4), in oral chemotherapy. CMEs were isolated and characterized, and ARV-825-loaded CME formulations were prepared and evaluated through various in vitro and in vivo tests. The ARV-825-CME formulation exhibited an entrapment efficiency of 42.75 ± 5.05%, a particle size of 136.8 ± 1.94 nm, and a zeta potential of −32.75 ± 0.70 mV, ensuring stability and sustained drug release. In vitro studies showed a 5.4-fold enhancement in drug release kinetics compared to the free ARV-825 solution. Permeability studies indicated a 3.2-fold increase in apparent permeability, suggesting improved cellular uptake. Cytotoxicity assays demonstrated potent anticancer activity, with IC50 values decreasing by 1.5 to 2-fold in cancer cell lines SF8628 DIPG and H1975R (resistant to Osimertinib). In vivo pharmacokinetic studies in Sprague-Dawley rats revealed superior systemic absorption and bioavailability of ARV-825 from CMEs, with a 2.55-fold increase in plasma concentration and a 5.56-fold increase in AUC. Distribution studies confirmed absorption through the ileum. This research highlights the potential of CMEs as a promising delivery platform for ARV-825, enhancing its therapeutic efficacy and offering a novel approach to cancer treatment. Full article

The BET (bromodomain and extraterminal domain) family of proteins, particularly BRD4 (bromodomain-containing protein 4), plays a crucial role in transcription regulation and epigenetic mechanisms, impacting key cellular processes such as proliferation, differentiation, and the DNA damage response. BRD4, the most studied member of this family, binds to acetylated lysines on both histones and non-histone proteins, thereby regulating gene expression and influencing diverse cellular functions such as the cell cycle, tumorigenesis, and immune responses to viral infections. Given BRD4’s involvement in these fundamental processes, it is implicated in various diseases, including cancer and inflammation, making it a promising target for therapeutic development. This review comprehensively explores the roles of the BET family in gene transcription, DNA damage response, and viral infection, discussing the potential of targeted small-molecule compounds and highlighting BET proteins as promising candidates for anticancer therapy. Full article

Bromodomain and extra-terminal domain (BET) proteins are epigenetic modulators that regulate gene transcription through interacting with acetylated lysine residues of histone proteins. BET proteins have multiple roles in regulating key cellular functions such as cell proliferation, differentiation, inflammation, oxidative and redox balance, and immune responses. As a result, BET proteins have been found to be actively involved in a broad range of human lung diseases including acute lung inflammation, asthma, pulmonary arterial hypertension, pulmonary fibrosis, and chronic obstructive pulmonary disease (COPD). Due to the identification of specific small molecular inhibitors of BET proteins, targeting BET in these lung diseases has become an area of increasing interest. Emerging evidence has demonstrated the beneficial effects of BET inhibitors in preclinical models of various human lung diseases. This is, in general, largely related to the ability of BET proteins to bind to promoters of genes that are critical for inflammation, differentiation, and beyond. By modulating these critical genes, BET proteins are integrated into the pathogenesis of disease progression. The intrinsic histone acetyltransferase activity of bromodomain-containing protein 4 (BRD4) is of particular interest, seems to act independently of its bromodomain binding activity, and has implication in some contexts. In this review, we provide a brief overview of the research on BET proteins with a focus on BRD4 in several major human lung diseases, the underlying molecular mechanisms, as well as findings of targeting BET proteins using pharmaceutical inhibitors in different lung diseases preclinically. Full article

Bromodomain-containing protein 4 (BRD4) is an intracellular protein that regulates expression of various cellular functions. This study investigated whether BRD4 inhibition can alter the immunomodulatory and antitumor effects of radiation therapy (RT). A murine breast cancer cell line was implanted into BALB/c mice. The dual-tumor model was used to evaluate the abscopal effects of RT. A total of 24 Gy was delivered and BRD4 inhibitor was injected intravenously. Tumor size was measured, and in vivo imaging was performed to evaluate tumor growth. Flow cytometry and immunohistochemistry were performed to examine immunologic changes upon treatment. The combination of BRD4 inhibitor and RT significantly suppressed tumor growth compared to RT alone. BRD4 inhibitor reduced the size of the unirradiated tumor, indicating that it may induce systemic immune responses. The expression of HIF-1α and PD-L1 in the tumor was significantly downregulated by the BRD4 inhibitor. The proportion of M1 tumor-associated macrophages (TAMs) increased, and the proportion of M2 TAMs decreased upon BRD4 inhibition. BRD4 inhibitor expanded CD4⁺ and CD8⁺ T cell populations in the tumor microenvironment. Additionally, splenic monocytic myeloid derived suppressor cells, which were increased by RT, were reduced upon the addition of BRD4 inhibitor. Therefore, the addition of BRD4 inhibitor significantly enhanced the systemic antitumor responses of local RT. Full article

(1) Background: Despite the evidence that ferroptosis is involved in myocardial ischemia-reperfusion (MIR), the critical regulator of ferroptosis in MIR remains unclear. (2) Methods: We included three GEO datasets and a set of ferroptosis-related genes with 259 genes. Following the identification of the differentially expressed ferroptosis-related genes (DEFRGs) and hub genes, we performed the functional annotation, protein–protein interaction network, and immune infiltration analysis. The GSE168610 dataset, a cell model, and an animal model were then used to verify key genes. (3) Results: We identified 17 DEFRGs and 9 hub genes in the MIR samples compared to the control. Heme oxygenase 1 (Hmox1), activating transcription factor 3 (Atf3), epidermal growth factor receptor (Egfr), and X-box binding protein 1 (Xbp1) were significantly upregulated in response to ischemic and hypoxic stimuli. In contrast, glutathione peroxidase 4 (Gpx4) and vascular endothelial growth factor A (Vegfa) were consistently decreased in either the oxygen and glucose deprivation/reoxygenation cell or the MIR mouse model. (4) Conclusions: This study emphasized the relevance of ferroptosis in MIR. It has been successfully demonstrated that nine ferroptosis-related genes (Hmox1, Atf3, Egfr, Gpx4, Cd44, Vegfa, asparagine synthetase (Asns), Xbp1, and bromodomain containing 4 (Brd4)) are involved in the process. Additional studies are needed to explore potential therapeutic targets for MIR. Full article

BRD4 (bromodomain-containing protein 4) is an epigenetic reader that realizes histone proteins and promotes the transcription of genes linked to cancer progression and non-cancer diseases such as acute heart failure and severe inflammation. The highly conserved N-terminal bromodomain (BD1) recognizes acylated lysine residues to organize the expression of genes. As such, BD1 is essential for disrupting BRD4 interactions and is a promising target for cancer treatment. To identify new BD1 inhibitors, a SuperDRUG2 database that contains more than 4600 pharmaceutical compounds was screened using in silico techniques. The efficiency of the AutoDock Vina1.1.2 software to anticipate inhibitor-BRD4-BD1 binding poses was first evaluated based on the co-crystallized R6S ligand in complex with BRD4-BD1. From database screening, the most promising BRD4-BD1 inhibitors were subsequently submitted to molecular dynamics (MD) simulations integrated with an MM-GBSA approach. MM-GBSA computations indicated promising BD1 binding with a benzonaphthyridine derivative, pyronaridine (SD003509), with an energy prediction (ΔG_binding) of −42.7 kcal/mol in comparison with −41.5 kcal/mol for a positive control inhibitor (R6S). Pharmacokinetic properties predicted oral bioavailability for both ligands, while post-dynamic analyses of the BRD4-BD1 binding pocket demonstrated greater stability for pyronaridine. These results confirm that in silico studies can provide insight into novel protein–ligand regulators, specifically that pyronaridine is a potential cancer drug candidate. Full article

Aging is a key independent risk factor of various vascular diseases, for which the regulatory mechanisms remain largely unknown. Bromodomain-containing protein 4 (BRD4) is a member of the Bromodomain and Extra-Terminal domain (BET) family and is an epigenetic reader playing diverse roles in regulating transcriptional elongation, chromatin remodeling, DNA damage response, and alternative splicing in various cells and tissues. While BRD4 was initially recognized for its involvement in cancer progression, recent studies have revealed that the aberrant expression and impaired function of BRD4 were highly associated with aging-related vascular pathology, affecting multiple key biological processes in the vascular cells and tissues, providing new insights into the understanding of vascular pathophysiology and pathogenesis of vascular diseases. This review summarizes the recent advances in BRD4 biological function, and the progression of the studies related to BRD4 in aging-associated vascular pathologies and diseases, including atherosclerosis, aortic aneurism vascular neointima formation, pulmonary hypertension, and essential hypertension, providing updated information to advance our understanding of the epigenetic mechanisms in vascular diseases during aging and paving the way for future research and therapeutic approaches. Full article

(1) Background: There is an urgent need for effective treatments for cocaine use disorder (CUD), and new pharmacological approaches targeting epigenetic mechanisms appear to be promising options for the treatment of this disease. Dopamine Transporter (DAT) transgenic rats recently have been proposed as a new animal model for studying susceptibility to CUD. (2) Methods: DAT transgenic rats were treated chronically with cocaine (10 mg/kg) for 8 days, and the expression of epigenetic modulators, Lysine Demethylase 6B (KDM6B) and Bromodomain-containing protein 4 (BRD4), was examined in the prefrontal cortex (PFC). (3) Results: We show that only full knockout (KO) of DAT impacts basal levels of KDM6B in females. Additionally, cocaine altered the expression of both epigenetic markers in a sex- and genotype-dependent manner. In response to chronic cocaine, KDM6B expression was decreased in male rats with partial DAT mutation (HET), while no changes were observed in wild-type (WT) or KO rats. Indeed, while HET male rats have reduced KDM6B and BRD4 expression, HET female rats showed increased KDM6B and BRD4 expression levels, highlighting the impact of sex on epigenetic mechanisms in response to cocaine. Finally, both male and female KO rats showed increased expression of BRD4, but only KO females exhibited significantly increased KDM6B expression in response to cocaine. Additionally, the magnitude of these effects was bigger in females when compared to males for both epigenetic enzymes. (4) Conclusions: This preliminary study provides additional support that targeting KDM6B and/or BRD4 may potentially be therapeutic in treating addiction-related behaviors in a sex-dependent manner. Full article