The chronic rhinosinusitis with nasal polyp patient journey in the United States and Europe.

In this letter to the editor, we present questionnaire-based data assessing the patient journey of adults with moderate-severe Chronic Rhinosinusitis with Nasal Polyps (CRSwNP) in the USA and five European countries. These data highlight how long and difficult the patient journey with CRSwNP can be and how improved disease awareness among physicians could lead to more timely diagnosis and treatment, and hence improved management of patients.

Sustained efficacy of mepolizumab in patients with severe chronic rhinosinusitis with nasal polyps: SYNAPSE 24-week treatment-free follow-up.

BACKGROUND: In the 52-week Phase III SYNAPSE study, mepolizumab given every 4 weeks (100 mg subcutaneously) reduced nasal polyp (NP) size, improved symptoms and quality of life (QoL), and reduced corticosteroid use and number of sinus surgeries in patients with severe chronic rhinosinusitis with nasal polyps (CRSwNP), versus placebo. Because the durability of mepolizumab's efficacy after discontinuation is poorly understood in CRSwNP, the efficacy of mepolizumab after discontinuation was analyzed in severe CRSwNP, over a 24-week follow-up. METHODS: Changes from SYNAPSE baseline to end of treatment (week 52) and end of follow-up (week 76) were assessed for total endoscopic NP score, nasal obstruction and overall symptoms visual analog scale scores, and 22-item Sino-Nasal Outcome Test score. Time to first sinus surgery, time to first corticosteroid use, and geometric mean blood eosinophil counts (BECs) were also assessed. RESULTS: Among 134 follow-up patients, clinical improvements observed with mepolizumab versus placebo were partially evident 24 weeks after discontinuation despite BEC returning to baseline. The mean (95% confidence interval [CI]) change from baseline in NP score (week 52: -1.3 [1.8 to -0.9] vs. -0.3 [-0.6 to 0.1]; week 76: -1.2 [-1.6 to -0.7] vs. -0.1 [-0.5 to 0.3]) and the proportion of patients having sinus surgery (week 52: 4% vs. 25%; week 76: 9% vs. 31%) remained substantially improved with mepolizumab versus placebo. Mepolizumab-associated improvements in overall symptoms, quality of life, and corticosteroid use versus placebo were partially sustained at week 76. CONCLUSION: Fifty-two weeks of mepolizumab treatment is associated with sustained clinical benefits up to 24 weeks after discontinuation in patients with severe CRSwNP, which should be considered by physicians when making treatment decisions.

Mepolizumab Reduces Systemic Corticosteroid Use in Chronic Rhinosinusitis With Nasal Polyps.

BACKGROUND: Systemic corticosteroids (SCSs) are associated with short- and long-term adverse effects. OBJECTIVE: To assess mepolizumab efficacy according to prior SCS use and characterize mepolizumab's SCS-sparing capabilities, in patients with severe chronic rhinosinusitis with nasal polyps. METHODS: In the randomized, double-blind, phase III SYNAPSE trial (NCT03085797), adults with severe chronic rhinosinusitis with nasal polyps eligible for repeat sinus surgery despite standard of care treatment received mepolizumab (100 mg subcutaneously) or placebo every 4 weeks for 52 weeks. The impact of prior SCS courses (0/1/>1) on mepolizumab versus placebo treatment responses (changes from baseline in total endoscopic nasal polyp [week 52], nasal obstruction visual analog scale [weeks 49-52], and 22-item Sino-Nasal Outcome Test total [week 52] scores) was analyzed post hoc. To characterize mepolizumab's SCS-sparing capabilities, time-to-first SCS course for nasal polyps (prespecified) and total prednisolone-equivalent oral corticosteroid dose by patient baseline characteristics (post hoc, in patients with ≥1 SCS course during SYNAPSE) were assessed up to week 52. RESULTS: Mepolizumab versus placebo improved treatment responses, irrespective of prior SCS use. By week 52, the probability of requiring SCSs for nasal polyps (Kaplan-Meier estimate [95% CI]) was lower with mepolizumab (25.4% [20.0-32.1]) versus placebo (37.5% [31.1-44.6]). In patients requiring 1 or more dose of SCSs, total (mean ± SD mg/y) prednisolone-equivalent oral corticosteroid dose was lower with mepolizumab (438.9 ± 350.40) versus placebo (505.2 ± 455.091), overall and irrespective of prior sinus surgeries, blood eosinophil count, or comorbidities. CONCLUSIONS: Mepolizumab is associated with clinical benefits in patients with severe chronic rhinosinusitis with nasal polyps regardless of prior SCS use and has an SCS-sparing effect.

The Unified Airway Hypothesis: Evidence From Specific Intervention With Anti-IL-5 Biologic Therapy.

The unified airway hypothesis proposes that upper and lower airway diseases reflect a single pathological process manifesting in different locations within the airway. Functional, epidemiological, and pathological evidence has supported this well-established hypothesis for some time. However, literature on the pathobiologic roles/therapeutic targeting of eosinophils and IL-5 in upper and lower airway diseases (including asthma, chronic rhinosinusitis with nasal polyps [CRSwNP], and nonsteroidal anti-inflammatory drug-exacerbated respiratory disease) has recently emerged. This narrative review revisits the unified airway hypothesis by searching the scientific literature for recent learnings and clinical trial/real-world data that provide a novel perspective on its relevance for clinicians. According to the available literature, eosinophils and IL-5 have important pathophysiological roles in both the upper and lower airways, although the impact of eosinophils and IL-5 may vary in asthma and CRSwNP. Some differential effects of anti-IL-5 and anti-IL-5-receptor therapies in CRSwNP have been observed, requiring further investigation. However, pharmaceutical targeting of eosinophils and IL-5 in patients with upper, lower, and comorbid upper and lower airway inflammation has led to clinical benefit, supporting the hypothesis that these are linked conditions manifesting in different locations. Consideration of this approach may improve patient care and aid clinical decision making.

Mitochondrial Ultrastructure and Activity Are Differentially Regulated by Glycolysis-, Krebs Cycle-, and Microbiota-Derived Metabolites in Monocytes.

Several intermediate metabolites harbour cell-signalling properties, thus, it is likely that specific metabolites enable the communication between neighbouring cells, as well as between host cells with the microbiota, pathogens, and tumour cells. Mitochondria, a source of intermediate metabolites, participate in a wide array of biological processes beyond that of ATP production, such as intracellular calcium homeostasis, cell signalling, apoptosis, regulation of immune responses, and host cell-microbiota crosstalk. In this regard, mitochondria's plasticity allows them to adapt their bioenergetics status to intra- and extra-cellular cues, and the mechanisms driving such plasticity are currently a matter of intensive research. Here, we addressed whether mitochondrial ultrastructure and activity are differentially shaped when human monocytes are exposed to an exogenous source of lactate (derived from glycolysis), succinate, and fumarate (Krebs cycle metabolic intermediates), or butyrate and acetate (short-chain fatty acids produced by intestinal microbiota). It has previously been shown that fumarate induces mitochondrial fusion, increases the mitochondrial membrane potential (Δψm), and reshapes the mitochondrial cristae ultrastructure. Here, we provide evidence that, in contrast to fumarate, lactate, succinate, and butyrate induce mitochondrial fission, while acetate induces mitochondrial swelling. These traits, along with mitochondrial calcium influx kinetics and glycolytic vs. mitochondrial ATP-production rates, suggest that these metabolites differentially shape mitochondrial function, paving the way for the understanding of metabolite-induced metabolic reprogramming of monocytes and its possible use for immune-response intervention.

Evaluating enrollment and outcome criteria in trials of biologics for chronic rhinosinusitis with nasal polyps.

OBJECTIVE: Treatment for chronic rhinosinusitis with nasal polyps (CRSwNP) generally involves intranasal corticosteroids (INCS) and saline irrigation, followed by short courses of systemic corticosteroids (SCS) or surgery with postoperative medical therapy for patients who do not respond to INCS. However, both SCS use and surgery are associated with a range of adverse effects or complications, have a high recurrence rate, and are unsuitable for some patients. Biologics targeting the underlying pathophysiology are promising treatment alternatives for these patients. Dupilumab, omalizumab, and mepolizumab are approved for use in patients with severe, uncontrolled CRSwNP. However, the lack of a consistent definition of severe CRSwNP makes the decision to initiate biologic treatment particularly complex. Furthermore, the position of each biologic in the overall management of CRSwNP remains to be clarified. DATA SOURCES: Publications reporting results of phase III trials of dupilumab, omalizumab, mepolizumab, and benralizumab in the treatment of CRSwNP. STUDY SELECTIONS: Randomized, controlled phase III trials of biologics approved for CRSwNP. RESULTS: These trials all used different enrollment criteria. We discuss the complexities of assessing CRSwNP disease severity and highlight how these impact comparisons of the populations and outcomes of the phase III biologic trials. CONCLUSION: To position biologic agents appropriately within the existing CRSwNP treatment paradigm, future trials will need to include comparable patient populations and standardized outcome measures. Such trials will help to ensure that biologic treatment is targeted appropriately to support optimal clinical outcomes.

The roles of eosinophils and interleukin-5 in the pathophysiology of chronic rhinosinusitis with nasal polyps.

Chronic rhinosinusitis with nasal polyps (CRSwNP) is generally associated with eosinophilic tissue infiltration linked to type 2 inflammation and characterized by elevated levels of interleukin (IL)-5 and other type 2 inflammatory mediators. Although distinct and overlapping contributions of eosinophils and IL-5 to CRSwNP pathology are still being explored, they are both known to play an important role in NP inflammation. Eosinophils secrete numerous type 2 inflammatory mediators including granule proteins, enzymes, cytokines, chemokines, growth factors, lipids, and oxidative products. IL-5 is critical for the differentiation, migration, activation, and survival of eosinophils but is also implicated in the biological functions of mast cells, basophils, innate lymphoid cells, B cells, and epithelial cells. Results from clinical trials of therapeutics that target type 2 inflammatory mediators (including but not limited to anti-IL-5, anti-immunoglobulin-E, and anti-IL-4/13) may provide further evidence of how eosinophils and IL-5 contribute to CRSwNP. Finally, the association between eosinophilia/elevated IL-5 and greater rates of NP recurrence after endoscopic sinus surgery (ESS) suggests that these mediators may have utility as biomarkers of NP recurrence in diagnosing and assessing the severity of CRSwNP. This review provides an overview of eosinophil and IL-5 biology and explores the literature regarding the role of these mediators in CRSwNP pathogenesis and NP recurrence following ESS. Based on current published evidence, we suggest that although eosinophils play a key role in CRSwNP pathophysiology, IL-5, a cytokine that activates these cells, also represents a pertinent and effective treatment target in patients with CRSwNP.

Mepolizumab for chronic rhinosinusitis with nasal polyps: Treatment efficacy by comorbidity and blood eosinophil count.

BACKGROUND: In the phase III SYNAPSE study, mepolizumab reduced nasal polyp (NP) size and nasal obstruction in chronic rhinosinusitis with NP. OBJECTIVE: We sought to assess the efficacy of mepolizumab in patients from SYNAPSE grouped by comorbid asthma, aspirin-exacerbated respiratory disease (AERD), and baseline blood eosinophil count (BEC). METHODS: SYNAPSE, a randomized, double-blind, 52-week study (NCT03085797), included patients with severe bilateral chronic rhinosinusitis with NP eligible for surgery despite intranasal corticosteroid treatment. Patients received 4-weekly subcutaneous mepolizumab 100 mg or placebo plus standard of care for 52 weeks. Coprimary end points were change in total endoscopic NP score (week 52) and nasal obstruction visual analog scale score (weeks 49-52). Subgroup analyses by comorbid asthma and AERD status, and post hoc by BEC, were exploratory. RESULTS: Analyses included 407 patients (289 with asthma; 108 with AERD; 371 and 278 with BEC counts ≥150 or ≥300 cells/µL, respectively). The proportion of patients with greater than or equal to 1-point improvement from baseline in NP score was higher with mepolizumab versus placebo across comorbid diseases (asthma: 52.9% vs 29.5%; AERD: 51.1% vs 20.6%) and baseline BEC subgroups (<150 cells/µL: 55.0% vs 31.3%; ≥150 cells/µL: 49.5% vs 28.1%; <300 cells/µL: 50.7% vs 29.0%; ≥300 cells/µL: 50.4% vs 28.1%). A similar trend was observed in patients without comorbid asthma or AERD. More patients had more than 3-point improvement in nasal obstruction VAS score with mepolizumab versus placebo across comorbid subgroups. CONCLUSIONS: Mepolizumab reduced polyp size and nasal obstruction in chronic rhinosinusitis with NP regardless of the presence of comorbid asthma or AERD.

Mepolizumab improves clinical outcomes in patients with severe asthma and comorbid conditions.

BACKGROUND: Comorbidities can complicate the management of severe asthma; therefore, the presence of comorbid conditions or traits often need to be considered when considering treatment options for patients with severe asthma. The aim of this analysis is to investigate the efficacy of mepolizumab in patients with severe eosinophilic asthma and comorbidities. METHODS: This was a post hoc analysis (GSK ID:209140) of data from the Phase IIb/III studies DREAM, MENSA, SIRIUS, and MUSCA. Patients aged ≥ 12 years with severe eosinophilic asthma were randomized to: mepolizumab 750, 250, or 75 mg intravenously or placebo (DREAM); mepolizumab 75 mg intravenously or 100 mg subcutaneously or placebo (MENSA); or mepolizumab 100 mg subcutaneously or placebo (SIRIUS and MUSCA) every 4 weeks for 24 weeks in SIRIUS and MUSCA, 32 weeks in MENSA or 52 weeks in DREAM. In this analysis the primary endpoint was the annual rate of clinically significant exacerbations; secondary endpoints were Asthma Control Questionnaire-5 score, St George's Respiratory Questionnaire total score, and pre-bronchodilator forced expiratory volume in 1 s at study end. Subgroups were based on comorbidities at baseline. RESULTS: Overall, 1878 patients received placebo (n = 689) or mepolizumab (n = 1189). Across all comorbidity subgroups mepolizumab reduced the rate of clinically significant exacerbations by 44-68% versus placebo, improved Asthma Control Questionnaire-5 score by 0.27-0.59 points, and improved St George's Respiratory Questionnaire total score by 5.0-11.6 points. Pre-bronchodilator forced expiratory volume in 1 s was improved by 27.1-286.9 mL in all but one comorbidity subgroup, the diabetes mellitus subgroup. CONCLUSIONS: Mepolizumab reduces exacerbations, and improves asthma control, health-related quality of life, and lung function in patients with severe eosinophilic asthma despite comorbid conditions, including upper respiratory conditions, psychopathologies, cardiovascular conditions, gastroesophageal reflux disease, diabetes mellitus, and obesity. TRIAL REGISTRATION: https://clinicaltrials.gov/ DREAM, MEA112997/NCT01000506; MENSA, MEA115588/NCT01691521; SIRIUS, MEA115575/NCT01842607; MUSCA, 200862/NCT02281318.

Benefit of switching to mepolizumab from omalizumab in severe eosinophilic asthma based on patient characteristics.

BACKGROUND: The OSMO study assessed the efficacy of switching to mepolizumab in patients with severe eosinophilic asthma that was uncontrolled whilst receiving omalizumab. The objective of this analysis was to assess the proportion of patients achieving pre-defined improvements in up to four efficacy outcomes and the relationship between patient baseline characteristics and treatment response. METHODS: This was a post hoc analysis of OSMO study data (GSK ID:204471; ClinicalTrials.gov No. NCT02654145). Patients with severe eosinophilic asthma uncontrolled by high-dose inhaled corticosteroids, other controller(s) and omalizumab subcutaneously (≥ 4 months) were switched to mepolizumab 100 mg administered subcutaneously. Endpoints included the proportion of responders-i.e. patients achieving a pre-defined clinical improvement in ≥ 1 of the following outcomes: (1) Asthma Control Questionnaire (ACQ)-5 score (≥ 0.5-points), (2) St George's Respiratory Questionnaire (SGRQ) total score (≥ 4-points), (3) pre-bronchodilator forced expiratory volume in 1s (FEV1; ≥ 100 mL), all at Week 32, and (4) annualised rate of clinically significant exacerbations (≥ 50% reduction). RESULTS: Of the 145 patients included, 94%, 83%, 63% and 31% were responders for ≥ 1, ≥ 2, ≥ 3 and 4 outcomes, respectively; 75% and 78% were ACQ-5 and SGRQ score responders, and 50% and 69% were FEV1 and exacerbation responders. Subgroup analyses demonstrated improvements irrespective of baseline blood eosinophil count, prior omalizumab treatment regimen/duration, comorbidities, prior exacerbation history, maintenance oral corticosteroid use, ACQ-5 and SGRQ scores, and body weight/body mass index. CONCLUSIONS: After switching to mepolizumab, almost all patients with uncontrolled severe eosinophilic asthma on omalizumab achieved a beneficial response in ≥ 1 clinical outcome. Improvements were observed regardless of baseline characteristics. Trial registration This manuscript is a post hoc analysis of data from the OSMO study. ClinicalTrials.gov, NCT02654145. Registered January 13, 2016.

Mepolizumab for chronic rhinosinusitis with nasal polyps (SYNAPSE): a randomised, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: Chronic rhinosinusitis with nasal polyps affects approximately 2-4% of the general population, and long-term use of systemic corticosteroids is associated with adverse effects. The aim of this study was to assess the efficacy and safety of mepolizumab in adults with recurrent, refractory severe bilateral chronic rhinosinusitis with nasal polyps. METHODS: SYNAPSE was a randomised, double-blind, placebo-controlled, parallel-group, phase 3 trial done at 93 centres, mainly hospitals, in 11 countries. Eligible patients were aged 18 years or older with recurrent, refractory, severe, bilateral nasal polyp symptoms (nasal obstruction symptom visual analogue scale [VAS] score of >5), were eligible for repeat nasal surgery (overall symptoms VAS score >7 and endoscopic nasal polyps score of ≥5, with a minimum score of 2 in each nasal cavity) despite standard of care treatment, and had to have at least one nasal surgery in the past 10 years. Patients were randomly assigned (1:1), using permuted block design, to receive either 100 mg mepolizumab subcutaneously or placebo once every 4 weeks, in addition to standard of care (mometasone furoate intranasal spray for at least 8 weeks before screening and during the study, saline nasal irrigations, systemic corticosteroids or antibiotics, or both), as required, for 52 weeks. Site staff, the central study team, and patients were masked to study treatment and absolute blood eosinophil counts. The coprimary endpoints were change from baseline in total endoscopic nasal polyp score at week 52 and in mean nasal obstruction VAS score during weeks 49-52, assessed in the intention-to-treat population (ITT). This study is registered with ClinicalTrials.gov, NCT03085797. FINDINGS: From May 25, 2017, to Dec 12, 2018, 854 patients were screened for eligibility. 414 patients were randomly assigned with 407 included in the ITT population; 206 received mepolizumab and 201 received placebo. Total endoscopic nasal polyp score significantly improved at week 52 from baseline with mepolizumab versus placebo (adjusted difference in medians -0·73, 95% CI -1·11 to -0·34; p<0·0001) and nasal obstruction VAS score during weeks 49-52 also significantly improved (-3·14, -4·09 to -2·18; p<0·0001). Adverse events considered related to study treatment were reported in 30 (15%) of 206 patients receiving mepolizumab and 19 (9%) of 201 receiving placebo. On-treatment serious adverse events occurred in 12 (6%) patients receiving mepolizumab and 13 (6%) receiving placebo; none were considered related to treatment in those receiving mepolizumab. One death was reported in the placebo group (myocardial infarction; death occurred 99 days after the last dose) and was considered unrelated to the treatment. INTERPRETATION: Mepolizumab treatment improved nasal polyp size and nasal obstruction compared with placebo, with no new safety indications, in patients with recurrent, refractory severe chronic rhinosinusitis with nasal polyps. These findings suggest that mepolizumab provides an effective add-on treatment option to standard of care in this population. FUNDING: GlaxoSmithKline.

Immune Responses Following BCG Immunization of Infants in Uganda and United Kingdom Are Similar for Purified Protein Derivative but Differ for Secretory Proteins of Mycobacterium tuberculosis.

Introduction: The immunogenicity of BCG vaccination in infants differs between populations. We hypothesized that prenatal exposure to mycobacterial antigens might explain the differences in immune responses to BCG seen in other studies of infants in Africa and the United Kingdom (UK) and we explored this in birth cohorts in Uganda and the UK. Materials and Methods: Blood samples were obtained from BCG-immunized infants of mothers with (n = 110) and without (n = 121) latent Mycobacterium tuberculosis infection (LTBI) in Uganda and BCG-immunized infants of mothers without LTBI (n = 25) in the UK at 10 and 52 weeks after birth. Cytokine and chemokine responses to PPD were measured to assess responses to BCG immunization, and to ESAT6/CFP10 to assess exposure to or infection with M. tuberculosis or non-tuberculous mycobacteria (NTM) in 6-day whole blood culture supernatants by a 17-plex Luminex assay. Median responses were compared between Ugandan infants (together, and separated by maternal LTBI status) and UK infants. Results: The IFN-γ response to BCG vaccination was similar between Ugandan and UK infants at 10 and 52 weeks. At week 52, TNF production was marginally higher in Ugandan infants, but after adjusting for multiple comparisons this difference was not significant. At weeks 10 and 52, stimulation of blood with ESAT6/CFP10 produced significantly higher IFN-γ, TNF, IL-12p40, IL-1α, IL-1ß, IL-1Ra, IP-10, MIP-1α, MIP-1ß, and GM-CSF in Ugandan compared to UK infants. Stimulation of blood with ESAT6/CFP10 produced significantly higher amounts of IL-8 (p = 0.0001), IL-10 (p = 0.0022), and IL-13 (p = 0.0020) in the UK than in Ugandan infants of mothers without LTBI at week 10, but not at week 52. Conclusions: Immune responses to mycobacterial antigens following BCG immunization are similar for PPD, but differ for ESAT6/CFP10, between infants in Uganda and the UK. Neither maternal LTBI nor infant exposure to or infection with mycobacteria impacts the response to BCG. The observed global differences in immune response to BCG immunization are likely to be due to other causes.

Human Bronchial Epithelial Cell-derived Factors from Severe Asthmatic Subjects Stimulate Eosinophil Differentiation.

Activated bronchial epithelial cells (BEC) release various alarmins, including thymic stromal lymphopoietin (TSLP), that drive type 2 inflammation. We hypothesize that BEC-derived factors promote in situ eosinophil differentiation and maturation, a process that is driven by an IL-5-rich microenvironment in asthmatic airways. To assess the eosinophilopoietic potential of epithelial-derived factors, eosinophil/basophil colony forming units (Eo/B-CFU) were enumerated in 14-day methylcellulose cultures of blood-derived nonadherent mononuclear cells incubated with BEC supernatants (BECSN) from healthy nonatopic controls (n = 8), mild atopic asthmatics (n = 9), and severe asthmatics (n = 5). Receptor-blocking antibodies were used to evaluate the contribution of alarmins. Modulation of the mRNA expression of transcription factors that are crucial for eosinophil differentiation was evaluated. BECSN stimulated the clonogenic expansion of eosinophil progenitors in vitro. In the presence of IL-5, Eo/B-CFU numbers were significantly greater in cocultures of BESCN from severe asthmatics compared with other groups. This was attenuated in the presence of a TSLP (but not an IL-33) receptor-blocking antibody. Recombinant human TSLP (optimal at 100 pg/ml) stimulated Eo/B-CFU growth, which was significantly enhanced in the presence of IL-5 (1 ng/ml). Overnight culture of CD34+ cells with IL-5 and TSLP synergistically increased GATA-binding factor 2 and CCAAT/enhancer-binding protein α mRNA expression. The eosinophilopoietic potential of factors derived from BEC is increased in severe asthma. Our data suggest that TSLP is a key alarmin that is produced by BECs and promotes in situ eosinophilopoiesis in a type 2-rich microenvironment.

Structural features and inhibitors of bromodomains.

Bromodomains are conserved structural modules responsible for recognizing acetylated-lysine residues on histone tails and other transcription-associated proteins, such as transcription factors and co-factors. Owing to their important functions in the regulation of ordered gene transcription in chromatin, bromodomains of the BET family proteins have recently been shown as druggable targets for a wide array of human diseases, including cancer and inflammation. Here we review the structural and functional features of the bromodomains and their small-molecule inhibitors. Additional new insights provided herein highlight the landscape of the ligand binding sites in the bromodomains that will hopefully facilitate further development of new inhibitors with optimal affinity and selectivity.

Structure-Guided Discovery of Selective Antagonists for the Chromodomain of Polycomb Repressive Protein CBX7.

The chromobox 7 (CBX7) protein of the polycomb repressive complex 1 (PRC1) functions to repress transcription of tumor suppressor p16 (INK4a) through long noncoding RNA, ANRIL (antisense noncoding RNA in the INK4 locus) directed chromodomain (ChD) binding to trimethylated lysine 27 of histone H3 (H3K27me3), resulting in chromatin compaction at the INK4a/ARF locus. In this study, we report structure-guided discovery of two distinct classes of small-molecule antagonists for the CBX7ChD. Our Class A compounds, a series including analogues of the previously reported MS452, inhibit CBX7ChD/methyl-lysine binding by occupying the H3K27me3 peptide binding site, whereas our Class B compound, the newly discovered MS351, appears to inhibit H3K27me3 binding when CBX7ChD is bound to RNA. Our crystal structure of the CBX7ChD/MS351 complex reveals the molecular details of ligand recognition by the aromatic cage residues that typically engage in methyl-lysine binding. We further demonstrate that MS351 effectively induces transcriptional derepression of CBX7 target genes, including p16 (INK4a) in mouse embryonic stem cells and human prostate cancer PC3 cells. Thus, MS351 represents a new class of ChD antagonists that selectively targets the biologically active form of CBX7 of the PRC1 in long noncoding RNA- and H3K27me3-directed gene transcriptional repression.

Small-molecule modulators of methyl-lysine binding for the CBX7 chromodomain.

Chromobox homolog 7 (CBX7) plays an important role in gene transcription in a wide array of cellular processes, ranging from stem cell self-renewal and differentiation to tumor progression. CBX7 functions through its N-terminal chromodomain (ChD), which recognizes trimethylated lysine 27 of histone 3 (H3K27me3), a conserved epigenetic mark that signifies gene transcriptional repression. In this study, we report the discovery of small molecules that inhibit CBX7ChD binding to H3K27me3. Our crystal structures reveal the binding modes of these molecules that compete against H3K27me3 binding through interactions with key residues in the methyl-lysine binding pocket of CBX7ChD. We further show that a lead compound, MS37452, derepresses transcription of Polycomb repressive complex target gene p16/CDKN2A by displacing CBX7 binding to the INK4A/ARF locus in prostate cancer cells. These small molecules have the potential to be developed into high-potency chemical modulators that target CBX7 functions in gene transcription in different disease pathways.

Thymic stromal lymphopoietin and IL-33 modulate migration of hematopoietic progenitor cells in patients with allergic asthma.

BACKGROUND: Thymic stromal lymphopoietin (TSLP) and IL-33 are considered important initiators of type 2 immunity. In asthmatic patients allergic inflammatory responses are associated with increased lung homing of bone marrow-derived CD34(+) hematopoietic progenitor cells (HPCs), which include eosinophil lineage-committed progenitor cells. In this study we investigated the role of TSLP and IL-33 in the recruitment of progenitor cells to the airways in asthmatic subjects. OBJECTIVES: We sought (i) to examine the effect of allergen inhalation challenge on expression levels of receptors for TSLP (thymic stromal lymphopoietin receptor [TSLPR] and CD127) and IL-33 (ST2) and (ii) investigate the functional effects of these cytokines on HPCs. METHODS: Consenting patients with mild atopic asthma (n = 19) with an FEV1 of 70% or greater and methacholine PC20 of 16 mg/mL or less were recruited. Blood- and sputum-extracted progenitors were phenotyped by flow cytometry before and 24 hours after allergen challenge. Functional responses, including cytokine production and migration to TSLP and IL-33, were assessed in vitro. RESULTS: Significant increases in mature eosinophil, HPC, and eosinophil lineage-committed progenitor cell counts in sputum were observed 24 hours after allergen and were associated with a significant allergen-induced increase in HPCs expressing TSLPR, CD127, and ST2. Pre-exposure to TSLP and IL-33 primed the migration of HPCs to a potent progenitor cell chemoattractant, stromal cell-derived factor 1α (CXCL12). Incubation with TSLP and IL-33 stimulated significant production of IL-5 and IL-13, but not IL-4, by HPCs. This priming effect was inhibited by blocking antibodies to TSLPR and ST2, respectively, and IL-13 receptor α1 in both scenarios. CONCLUSIONS: In allergic asthmatic responses increased lung homing of HPCs may be orchestrated by TSLP and IL-33 through an IL-13-dependent axis.

Privileged diazepine compounds and their emergence as bromodomain inhibitors.

Chemical compounds built on a diazepine scaffold have recently emerged as potent inhibitors of the acetyl-lysine binding activity of bromodomain-containing proteins, which is required for gene transcriptional activation in cancer and inflammation. Not only have these chemical compounds validated bromodomains as attractive epigenetic drug targets, but they have also brought to the forefront another application of the diazepine, which had already been regarded as a versatile chemical scaffold in rational drug design. This article reviews the success of diazepine compounds as therapeutic agents and examines the unique chemical and geometric features of this privileged scaffold that make it an excellent template for developing potent and selective molecules that control bromodomain-related gene expression in human diseases.

Broad heparin-binding haemagglutinin-specific cytokine and chemokine response in infants following Mycobacterium bovis BCG vaccination.

Heparin-binding haemagglutinin (HBHA)-specific immune responses have been linked to protection against tuberculosis (TB). We investigated the hypothesis that BCG vaccination of human infants primes an HBHA-specific response, using multiplex to measure secreted cytokines and chemokines following HBHA and Mycobacterium tuberculosis purified protein derivative (PPD) stimulation of diluted whole blood samples from BCG-vaccinated or -unvaccinated infants. Of 42 analytes measured, 24 and 32 significant, BCG-associated increases were detected in response to HBHA and PPD, respectively. Both response profiles included Th-1, Th-2, Th-17 and inflammatory cytokines and chemokines (e.g. IFN-γ, TNF-α, IL-5, IL-10, IL-13, IL-17, MIP-1α and MIP-1ß). We also found that six of the seven responses most closely correlated with IFN-γ were common to both HBHA and PPD. Notably, all HBHA-specific secretion of cytokines and chemokines from infant samples was dependent on previous BCG vaccination. Also, long-term persistence of HBHA-specific responses was found in adolescents with evidence of infant BCG vaccination. This study demonstrates for the first time BCG priming of an HBHA-specific immune response in infants that is characterised by a broad cytokine and chemokine signature. It also suggests a number of BCG vaccination associated, HBHA-induced responses that should be useful for future studies of biomarkers of protection against TB.