Ikappa-B kinase-2 inhibitor blocks inflammation in human airway smooth muscle and a rat model of asthma

PI3Kγδ inhibition suppresses key disease features in a rat model of asthma

BACKGROUND

Two isoforms of Phosphoinositide 3-kinase (PI3K), p110γ and p110δ, are predominantly expressed in leukocytes and represent attractive therapeutic targets for the treatment of allergic asthma. The study aim was to assess the impact of administration of an inhaled PI3Kγδ inhibitor (AZD8154) in a rat model of asthma.

METHODS

Firstly, we checked that the tool compound, AZD8154, inhibited rat PI3K γ & δ kinases using rat cell-based assays. Subsequently, a time-course study was conducted in a rat model of asthma to assess PI3K activity in the lung and how it is temporally associated with other key transcription pathways and asthma like features of the model. Finally, the impact on lung dosed AZD8154 on target engagement, pathway specificity, airway inflammation and lung function changes was assessed.

RESULTS

Data showed that AZD8154 could inhibit rat PI3K γ & δ isoforms and, in a rat model of allergic asthma the PI3K pathway was activated in the lung. Intratracheal administration of AZD8154 caused a dose related suppression PI3K pathway activation (reduction in pAkt) and unlike after budesonide treatment, STAT and NF-κB pathways were not affected by AZD8154. The suppression of the PI3K pathway led to a marked inhibition of airway inflammation and reduction in changes in lung function.

CONCLUSION

These data show that a dual PI3Kγδ inhibitor suppress key features of disease in a rat model of asthma to a similar degree as budesonide and indicate that dual PI3Kγδ inhibition may be an effective treatment for people suffering from allergic asthma.

Reducing False Positives through the Application of Fluorescence Lifetime Technology: A Comparative Study Using TYK2 Kinase as a Model System

The predominant assay detection methodologies used for enzyme inhibitor identification during early-stage drug discovery are fluorescence-based. Each fluorophore has a characteristic fluorescence decay, known as the fluorescence lifetime, that occurs throughout a nanosecond-to-millisecond timescale. The measurement of fluorescence lifetime as a reporter for biological activity is less common than fluorescence intensity, even though the latter has numerous issues that can lead to false-positive readouts. The confirmation of hit compounds as true inhibitors requires additional assays, cost, and time to progress from hit identification to lead drug-candidate optimization. To explore whether the use of fluorescence lifetime technology (FLT) can offer comparable benefits to label-free-based approaches such as RapidFire mass spectroscopy (RF-MS) and a superior readout compared to time-resolved fluorescence resonance energy transfer (TR-FRET), three equivalent assays were developed against the clinically validated tyrosine kinase 2 (TYK2) and screened against annotated compound sets. FLT provided a marked decrease in the number of false-positive hits when compared to TR-FRET. Further cellular screening confirmed that a number of potential inhibitors directly interacted with TYK2 and inhibited the downstream phosphorylation of the signal transducer and activator of transcription 4 protein (STAT4).

Nanomedicine-Based Therapeutics to Combat Acute Lung Injury

Acute lung injury (ALI) or its aggravated stage acute respiratory distress syndrome (ARDS) may lead to a life-threatening form of respiratory failure, resulting in high mortality of up to 30-40% in most studies. Although there have been decades of research since ALI was first described in 1967, the clinical therapeutic alternatives for ALI are still in a state of limited availability. Supportive treatment and mechanical ventilation still have priority. Despite some preclinical studies demonstrating the benefit of pharmacological interventions, none of these has been proved completely effective to date. Recent advances in nanotechnology may shed new light on the pharmacotherapy of ALI. Nanomedicine possesses targeting and synergistic therapeutic capability, thus boosting pharmaceutical efficacy and mitigating the side effects. Currently, a variety of nanomedicine with diverse frameworks and functional groups have been elaborately developed, in accordance with their lung targeting ability and the pathophysiology of ALI. The in-depth review of the current literature reveals that liposomes, polymers, inorganic materials, cell membranes, platelets, and other nanomedicine approaches have conferred attractive therapeutic benefits for ALI treatment. In this review, we explore the recent progress in the study of the nanomedicine-based therapy of ALI, presenting various nanomedical approaches, drug choices, therapeutic strategies, and outcomes, thereby providing insight into the trends.

Rhinovirus-induced CCL17 and CCL22 in Asthma Exacerbations and Differential Regulation by STAT6

The interplay of type-2 inflammation and antiviral immunity underpins asthma exacerbation pathogenesis. Virus infection induces type-2 inflammation-promoting chemokines CCL17 and CCL22 in asthma; however, mechanisms regulating induction are poorly understood. By using a human rhinovirus (RV) challenge model in human airway epithelial cells in vitro and mice in vivo, we assessed mechanisms regulating CCL17 and CCL22 expression. Subjects with mild to moderate asthma and healthy volunteers were experimentally infected with RV and airway CCL17 and CCL22 protein quantified. In vitro airway epithelial cell- and mouse-RV infection models were then used to define STAT6- and NF-κB-mediated regulation of CCL17 and CCL22 expression. Following RV infection, CCL17 and CCL22 expression was higher in asthma, which differentially correlated with clinical and immunological parameters. Air-liquid interface-differentiated primary epithelial cells from donors with asthma also expressed higher levels of RV-induced CCL22. RV infection boosted type-2 cytokine-induced STAT6 activation. In epithelial cells, type-2 cytokines and STAT6 activation had differential effects on chemokine expression, increasing CCL17 and suppressing CCL22, whereas NF-κB promoted expression of both chemokines. In mice, RV infection activated pulmonary STAT6, which was required for CCL17 but not CCL22 expression. STAT6-knockout mice infected with RV expressed increased levels of NF-κB-regulated chemokines, which was associated with rapid viral clearance. Therefore, RV-induced upregulation of CCL17 and CCL22 was mediated by NF-κB activation, whereas expression was differentially regulated by STAT6. Together, these findings suggest that therapeutic targeting of type-2 STAT6 activation alone will not block all inflammatory pathways during RV infection in asthma.

(3E,5E)-3,5-Bis(pyridin-3-methylene)-tetrahydrothiopyran-4-one enhances the inhibitory effect of gemcitabine on pancreatic cancer cells

Gemcitabine (GEM) is a commonly used treatment for advanced pancreatic cancer. However, chemoresistance and toxic side effect limits its clinical success. In an earlier study, our laboratory found that the curcumin analogue, (3E,5E)-3,5-Bis(pyridin-3-methylene)-tetrahydrothiopyran-4-one (FN2) had strong inhibitory effect on human pancreatic cancer cells. In the present study, we investigated the effects of FN2 in combination with GEM on growth inhibition and apoptosis in human pancreatic cancer Panc-1 cells. The results showed that the combination of FN2 and GEM synergistically inhibited the growth of Panc-1 cells. Panc-1 cells survived the GEM treatment became partially resistant to the drug. Treatment with FN2 in combination with GEM strongly inhibited the growth and stimulated apoptosis in the GEM resistant Panc-1 cells. Mechanistic studies showed that inhibition of cell growth and induction of apoptosis in the GEM resistant Panc-1 cells were associated with decreases in activation of NF-κB and Akt. FN2 in combination with GEM also decreased the level of Bcl-2 and increased the level of Bax. Results of the present study indicate that GEM in combination with FN2 may represent an effective strategy for improving the efficacy of GEM and decreasing the resistance of pancreatic cancer to GEM chemotherapy.

Regnase-1 degradation is crucial for IL-33- and IL-25-mediated ILC2 activation

Group 2 innate lymphoid cells (ILC2s) are a critical innate source of type 2 cytokines in allergic inflammation. Although ILC2s are recognized as a critical cell population in the allergic inflammation, the regulatory mechanism(s) of ILC2s are less well understood. Here, we show that Regnase-1, an immune regulatory RNAse that degrades inflammatory mRNAs, negatively regulates ILC2 function and that IκB kinase (IKK) complex-mediated Regnase-1 degradation is essential for IL-33- and IL-25-induced ILC2 activation. ILC2s from Regnase-1AA/AA mice expressing a Regnase-1 S435A/S439A mutant resistant to IKK complex-mediated degradation accumulated Regnase-1 protein in response to IL-33 and IL-25. IL-33- and IL-25-stimulated Regnase-1AA/AA ILC2s showed reduced cell proliferation and type 2 cytokine (IL-5, IL-9, and IL-13) production and increased cell death. In addition, Il2ra and Il1rl1, but not Il5, Il9, or Il13, mRNAs were destabilized in IL-33-stimulated Regnase-1AA/AA ILC2s. In vivo, Regnase-1AA/AA mice showed attenuated acute type 2 pulmonary inflammation induced by the instillation of IL-33, IL-25, or papain. Furthermore, the expulsion of Nippostrongylus brasiliensis was significantly delayed in Regnase-1AA/AA mice. These results demonstrate that IKK complex-mediated Regnase-1 degradation is essential for ILC2-mediated type 2 responses both in vitro and in vivo. Therefore, controlling Regnase-1 degradation is a potential therapeutic target for ILC2-contributed allergic disorders.

In vitro benchmarking of NF-κB inhibitors

Dysregulated activity of the transcription factors of the nuclear factor κb (NF-κB) family has been implicated in numerous cancer types, inflammatory diseases, autoimmune disease, and other disorders. As such, selective NF-κB pathway inhibition is an attractive target to researchers for preclinical and clinical drug development. A plethora of commercially and clinically available inhibitors claim to be NF-κB specific; however, such claims of specificity are rarely quantitative or benchmarked, making the biomedical literature difficult to contextualize. This imprecision is worsened because some NF-κB reporter systems have low signal-to-noise ratios. Herein, we use a robust, defined, commercially available reporter system to benchmark NF-κB agonists and antagonists for the field. We also functionally characterize a RELA fusion-positive ependymoma cell culture with validated NF-κB inhibitor compounds.

UL26 Attenuates IKKβ-Mediated Induction of Interferon-Stimulated Gene (ISG) Expression and Enhanced Protein ISGylation during Human Cytomegalovirus Infection

Viruses must negotiate cellular antiviral responses in order to replicate. Human cytomegalovirus (HCMV) is a prevalent betaherpesvirus that encodes a number of viral gene products that modulate cellular antiviral signaling. The HCMV U_L26 gene has previously been found to attenuate cytokine-activated NF-κB signaling, yet the role that U_L26 plays in modulating the host cell's global transcriptional response to infection is not clear. Here, we find that infection with a U_L26 deletion virus (ΔU_L26) induces a proinflammatory transcriptional environment that includes substantial increases in the expression of cytokine signaling genes relative to wild-type HCMV. These increases include NF-κB-regulated genes as well as interferon-stimulated genes (ISGs), such as ISG15 and bone marrow stromal cell antigen 2 (BST2). The ΔU_L26 mutant-mediated induction of ISG15 expression was found to drive increases in global protein ISGylation during ΔU_L26 mutant infection. However, short hairpin RNA (shRNA) and CRISPR-mediated targeting of ISG15 indicated that its induction does not restrict HCMV infection. In contrast, shRNA-mediated targeting of BST2 demonstrated that BST2 restricts HCMV cell-to-cell spread. In addition, the increased expression of both of these ISGs and the global enhancement in protein ISGylation were found to be dependent on the activity of the canonical inhibitor of NF-κB kinase beta (IKKβ). Both CRISPR-based and pharmacologically mediated inhibition of IKKβ blocked the induction of ISG15 and BST2. These results suggest significant cross-talk between the NF-κB and interferon signaling pathways and highlight the importance of IKK signaling and the HCMV U_L26 protein in shaping the antiviral response to HCMV.IMPORTANCE Modulation of cellular antiviral signaling is a key determinant of viral pathogenesis. Human cytomegalovirus (HCMV) is a significant source of morbidity in neonates and the immunosuppressed that contains many genes that modulate antiviral signaling, yet how these genes contribute to shaping the host cell's transcriptional response to infection is largely unclear. Our results indicate that the HCMV U_L26 protein is critical in preventing the establishment of a broad cellular proinflammatory transcriptional environment. Further, we find that the host gene IKKβ is an essential determinant governing the host cell's antiviral transcriptional response. Given their importance to viral pathogenesis, continuing to elucidate the functional interactions between viruses and the cellular innate immune response could enable the development of therapeutic strategies to limit viral infection.

TLR4-RelA-miR-30a signal pathway regulates Th17 differentiation during experimental autoimmune encephalomyelitis development

Background

Toll-like receptor 4 (TLR4) is well known for activating the innate immune system; however, it is also highly expressed in adaptive immune cells, such as CD4⁺ T-helper 17 (Th17) cells, which play a key role in multiple sclerosis (MS) pathology. However, the function and governing mechanism of TLR4 in Th17 remain unclear.

Methods

The changes of TLR4 in CD4⁺ T cells from MS patients and experimental autoimmune encephalomyelitis (EAE) mice were tested. TLR4-deficient (TLR4^−/−) naïve T cells were induced in vitro and transferred into Rag1^−/− mice to measure Th17 differentiation and EAE pathology. DNA sequence analyses combining with deletion fragments and mutation analyses, chromatin immunoprecipitation (ChIP), and electrophoretic mobility shift assay (EMSA) were used to explore the mechanism of TLR4 signaling pathway in regulating Th17 differentiation.

Results

The levels of TLR4 were increased in CD4⁺ Th17 cells both from MS patients and EAE mice, as well as during Th17 differentiation in vitro. TLR4^−/− CD4⁺ naïve T cells inhibited their differentiation into Th17, and transfer of TLR4^−/− CD4⁺ naïve T cells into Rag1^−/− mice was defective in promoting EAE, characterized by less demyelination and Th17 infiltration in the spinal cord. TLR4 signal enhanced Th17 differentiation by activating RelA, downregulating the expression of miR-30a, a negative regulator of Th17 differentiation. Inhibition of RelA activity increased miR-30a level, but decreased Th17 differentiation rate. Furthermore, RelA directly regulated the expression of miR-30a via specific binding to a conserved element of miR-30a gene.

Conclusions

TLR4^−/− CD4⁺ naïve T cells are inadequate in differentiating to Th17 cells both in vitro and in vivo. TLR4-RelA-miR-30a signal pathway regulates Th17 differentiation via direct binding of RelA to the regulatory element of miR-30a gene. Our results indicate modulating TLR4-RelA-miR-30a signal in Th17 may be a therapeutic target for Th17-mediated neurodegeneration in neuroinflammatory diseases.

pH-Responsive Nanoparticles Targeted to Lungs for Improved Therapy of Acute Lung Inflammation/Injury

Dysregulated vascular inflammation is the underlying cause of acute lung inflammation/injury (ALI). Bacterial infections and trauma cause ALI that may rapidly lead to acute respiratory distress syndrome (ARDS). There are no pharmacological therapies available to patients with ALI/ARDS, partially as drugs cannot specifically target the lungs. Herein, we developed a stimuli-responsive nanoparticle (NP) to target inflammatory lungs for ALI therapies. The NP is composed of a sharp acid-sensitive segment poly(β-amino esters) as a core for drug loading and controlled release and a polyethylene glycol-biotin on the particle surface available for bioconjugation, enabling lung targeting and extended circulation. The studies on dissipative particle dynamics simulation and characteristics of NPs suggest that anti-ICAM-1 antibodies can be coated to the particle surface and this coating is required to enhance lung targeting of NPs. A model drug of anti-inflammatory agent TPCA-1 is encapsulated in NPs with a high drug-loading content at 24% (w/w). In the mouse ALI model, our TPCA-1-loaded NPs coated with anti-ICAM-1 can target inflamed lungs after intravenous injection, followed by drug release triggered by the acid environment, thus mitigating lung inflammation and injury. Our studies reveal the rational design of nanotherapeutics for improved therapy of ALI, which may be applied to treating a wide range of vascular inflammation.

The IκB Kinases Restrict Human Cytomegalovirus Infection

Human cytomegalovirus (HCMV) is a ubiquitous herpesvirus that causes disease in immunosuppressed populations. HCMV has a complex relationship with innate immune signaling pathways. Specifically, HCMV has been found to block some aspects of inflammatory signaling while benefiting from others. Through analysis of knockout cell lines targeting the NF-κB regulatory kinases IκB kinase α (IKKα) and IKKβ, we find that the IKKs are host restriction factors that contribute to cytokine-mediated resistance to viral infection, limit the initiation of HCMV infection, and attenuate viral cell-to-cell spread. The HCMV UL26 protein is a viral immune modulator important for HCMV infection that has been shown to inhibit host cell NF-κB signaling, yet it has remained unclear how UL26-mediated NF-κB modulation contributes to infection. Here, we find that UL26 modulation of NF-κB signaling is separable from its contribution to high-titer viral replication. However, we find that IKKβ is required for the induction of cytokine expression associated with ΔUL26 infection. Collectively, our data indicate that the IKKs restrict infection but HCMV targets their signaling to modulate the cellular inflammatory environment.IMPORTANCE Innate immune signaling is a critical defense against viral infection and represents a central host-virus interaction that frequently determines the outcomes of infections. NF-κB signaling is an essential component of innate immunity that is extensively modulated by HCMV, a significant cause of morbidity in neonates and immunosuppressed individuals. However, the roles that various facets of NF-κB signaling play during HCMV infection have remained elusive. We find that the two major regulatory kinases in this pathway, IKKα and IKKβ, limit the initiation of infection, viral replication, and cell-to-cell spread. In addition, our results indicate that these kinases contribute differently to the host cell response to infection in the absence of a virally encoded NF-κB inhibitor, UL26. Given the importance of NF-κB in viral infection, elucidating the contributions of various NF-κB constituents to infection is an essential first step toward the possibility of targeting this pathway therapeutically.

Involvement of inhibitor kappa B kinase 2 (IKK2) in the regulation of vascular tone

Inhibitor kappa B kinase 2 (IKK2) plays an essential role in the activation of nuclear factor kappa B (NF-kB). Recently, it has been suggested that IKK2 acts as a myosin light chain kinase (MLCK) and contributes to vasoconstriction in mouse aorta. However, the underlying mechanisms are still unknown. Therefore, we investigated whether IKK2 acts as a MLCK or regulates the activity of myosin light chain phosphatase (MLCP). Pressure myograph was used to measure vascular tone in rat mesenteric arteries. Immunofluorescence staining was performed to identify phosphorylation levels of MLC (ser19), MYPT1 (thr853 and thr696) and CPI-17 (thr38). SC-514 (IKK2 inhibitor, 50 μM) induced relaxation in the mesenteric arteries pre-contracted with 70 mM high K⁺ solution or U-46619 (thromboxane analog, 5 μM). The relaxation induced by SC-514 was increased in the arteries pre-contracted with U-46619 compared to arteries pre-contracted with 70 mM high K⁺ solution. U-46619-induced contraction was decreased by treatment of SC-514 in the presence of MLCK inhibitor, ML-7 (10 μM). In the absence of intracellular Ca²⁺, U-46619 still induced contraction, which was decreased by treatment of SC-514. Furthermore, phosphorylation levels of MLC (ser19) and MYPT1 (thr853) were decreased by treatment of SC-514. IKK2 is involved in the vascular contraction through regulation of MLCP activity by phosphorylating MYPT1 at thr853 in rat mesenteric arteries. These findings suggest IKK2 could be a new pharmacological target for specific therapies of various vascular diseases.

Delivery system for budesonide based on lipid-DNA

Budesonide is a hydrophobic glucocorticoid with high anti-inflammatory activity for the treatment of asthma, inflammatory bowel disease and rheumatoid arthritis. A micellar drug-delivery system based on lipid-DNA may provide a strategy to maximize its drug efficacy and reduce adverse effects. In this work, we report the use of lipid-DNAA (UU11mer), featuring two hydrophobic alkyl chains and forming micelles at a comparatively low critical micelle concentration, to render budesonide water-soluble with a high loading capacity (LC). The inhibition of interleukin-8 (IL-8) release shows that the new delivery system retains the inhibitory activity in cell-based assays. In conclusion, this research provides a novel approach to formulate and administer budesonide in a non-invasive manner, which dramatically improves its water-solubility while retaining its bioavailability.

IκB Kinase α Is Required for Development and Progression of KRAS-Mutant Lung Adenocarcinoma

Although oncogenic activation of NFκB has been identified in various tumors, the NFκB-activating kinases (inhibitor of NFκB kinases, IKK) responsible for this are elusive. In this study, we determined the role of IKKα and IKKβ in KRAS-mutant lung adenocarcinomas induced by the carcinogen urethane and by respiratory epithelial expression of oncogenic KRASG12D Using NFκB reporter mice and conditional deletions of IKKα and IKKβ, we identified two distinct early and late activation phases of NFκB during chemical and genetic lung adenocarcinoma development, which were characterized by nuclear translocation of RelB, IκBβ, and IKKα in tumor-initiated cells. IKKα was a cardinal tumor promoter in chemical and genetic KRAS-mutant lung adenocarcinoma, and respiratory epithelial IKKα-deficient mice were markedly protected from the disease. IKKα specifically cooperated with mutant KRAS for tumor induction in a cell-autonomous fashion, providing mutant cells with a survival advantage in vitro and in vivo IKKα was highly expressed in human lung adenocarcinoma, and a heat shock protein 90 inhibitor that blocks IKK function delivered superior effects against KRAS-mutant lung adenocarcinoma compared with a specific IKKβ inhibitor. These results demonstrate an actionable requirement for IKKα in KRAS-mutant lung adenocarcinoma, marking the kinase as a therapeutic target against this disease.Significance: These findings report a novel requirement for IKKα in mutant KRAS lung tumor formation, with potential therapeutic applications. Cancer Res; 78(11); 2939-51. ©2018 AACR.

Modelling the asthma phenotype: impact of cigarette smoke exposure

Background

Asthmatics that are exposed to inhaled pollutants such as cigarette smoke (CS) have increased symptom severity. Approximately 25% of adult asthmatics are thought to be active smokers and many sufferers, especially in the third world, are exposed to high levels of inhaled pollutants. The mechanism by which CS or other airborne pollutants alter the disease phenotype and the effectiveness of treatment in asthma is not known. The aim of this study was to determine the impact of CS exposure on the phenotype and treatment sensitivity of rodent models of allergic asthma.

Methods

Models of allergic asthma were configured that mimicked aspects of the asthma phenotype and the effect of CS exposure investigated. In some experiments, treatment with gold standard asthma therapies was investigated and end-points such as airway cellular burden, late asthmatic response (LAR) and airway hyper-Reactivity (AHR) assessed.

Results

CS co-exposure caused an increase in the LAR but interestingly attenuated the AHR. The effectiveness of LABA, LAMA and glucocorticoid treatment on LAR appeared to be retained in the CS-exposed model system. The eosinophilia or lymphocyte burden was not altered by CS co-exposure, nor did CS appear to alter the effectiveness of glucocorticoid treatment. Steroids, however failed to reduce the neutrophilic inflammation in sensitized mice exposed to CS.

Conclusions

These model data have certain parallels with clinical findings in asthmatics, where CS exposure did not impact the anti-inflammatory efficacy of steroids but attenuated AHR and enhanced symptoms such as the bronchospasm associated with the LAR. These model systems may be utilised to investigate how CS and other airborne pollutants impact the asthma phenotype; providing the opportunity to identify novel targets.

Characterisation of a murine model of the late asthmatic response

BACKGROUND

The incidence of asthma is increasing at an alarming rate. While the current available therapies are effective, there are associated side effects and they fail to adequately control symptoms in all patient subsets. In the search to understand disease pathogenesis and find effective therapies hypotheses are often tested in animal models before progressing into clinical studies. However, current dogma is that animal model data is often not predictive of clinical outcome. One possible reason for this is the end points measured such as antigen-challenge induced late asthmatic response (LAR) is often used in early clinical development, but seldom in animal model systems. As the mouse is typically selected as preferred species for pre-clinical models, we wanted to characterise and probe the validity of a murine model exhibiting an allergen induced LAR.

METHODS

C57BL/6 mice were sensitised with antigen and subsequently topically challenged with the same antigen. The role of AlumTM adjuvant, glucocorticoid, long acting muscarinic receptor antagonist (LAMA), TRPA1, CD4+ and CD8+ T cells, B cells, Mast cells and IgE were determined in the LAR using genetically modified mice and a range of pharmacological tools.

RESULTS

Our data showed that unlike other features of asthma (e.g. cellular inflammation, elevated IgE levels and airway hyper-reactivity (AHR) the LAR required AlumTMadjuvant. Furthermore, the LAR appeared to be sensitive to glucocorticoid and required CD4+ T cells. Unlike in other species studied, the LAR was not sensitive to LAMA treatment nor required the TRPA1 ion channel, suggesting that airway sensory nerves are not involved in the LAR in this species. Furthermore, the data suggested that CD8+ T cells and the mast cell-B-cell - IgE axis appear to be protective in this murine model.

CONCLUSION

Together we can conclude that this model does feature steroid sensitive, CD4+ T cell dependent, allergen induced LAR. However, collectively our data questions the validity of using the murine pre-clinical model of LAR in the assessment of future asthma therapies.

Bufalin Inhibits the Inflammatory Effects in Asthmatic Mice through the Suppression of Nuclear Factor-Kappa B Activity

Asthma is an inflammatory airway disease characterized by increased infiltration of inflammatory cells into the airways and poor respiratory function. Bufalin is one of the biological ingredients obtained from Chansu. Bufalin was found to possess various pharmacological properties including anti-inflammatory activities. However, the effect of bufalin treatment on asthma has not yet been reported. Therefore, this study aimed to investigate the inhibitory effect of bufalin on asthmatic response in a murine model. A mouse asthma model was developed by ovalbumin (OVA) sensitization and challenge in the BALB/c mice. OVA-specific serum IgE and the levels of interleukin (IL)-4, IL-5, and IL-13 in bronchoalveolar lavage fluid (BALF) were determined by an enzyme-linked immunosorbent assay. Recruitment of inflammatory cells into BALF or lung tissues, and goblet cell hyperplasia were evaluated by histological staining. The expression levels of inhibitory subunit of nuclear factor-kappa B (NF-κB) alpha (IκBα) and phosphorylated p65 protein were measured by Western blot analyses. The results demonstrated that bufalin (5 and 10 mg/kg) markedly attenuated hyperresponsiveness, and strongly suppressed the OVA-induced increases of total inflammatory cells including macrophages, eosinophils, lymphocytes, and neutrophils in BALF. The levels of IL-4, IL-5, and IL-13 in BALF and OVA-specific IgE in serum were significantly reduced by bufalin. Histological staining of lung tissues showed that bufalin reduced inflammatory cell infiltration and goblet cell hyperplasia. The results of Western blotting indicated that bufalin suppressed the IκBα degradation from NF-κB, and reduced the level of phosphorylated p65 protein in the lung tissues. These data suggest that bufalin can exert its anti-inflammatory effects possibly through the inhibition of the NF-κB activity.

Efficacy of parthenolide on lung histopathology in a murine model of asthma

BACKGROUND

Parthenolide is the active constituent of the plant 'Tanacetum parthenium' (Feverfew) which has been used for centuries as a folk remedy for inflammatory conditions.

AIM OF THE STUDY

In this study we aimed to investigate the effects of parthenolide in a murine model of chronic asthma.

MATERIALS AND METHODS

Thirty-five BALB/c mice were divided into five groups; I (control), II (placebo), III (dexamethasone), IV (parthenolide) and V (dexamethasone and parthenolide combination). Lung histology was evaluated after treatment with the study drugs. Levels of interleukin (IL)-4 and IL-5 were determined by ELISA.

RESULTS

Histologic parameters except the number of mast and goblet cells improved in the parthenolide group when compared with placebo. All parameters except basal membrane thickness and number of mast cells were improved significantly better in the group receiving dexamethasone when compared with the parthenolide group. Improvement of most of the histologic parameters was similar in Groups III and V. Interleukin-4 levels were significantly reduced in the parthenolide group when compared to the placebo group.

CONCLUSION

We demonstrated that parthenolide administration alleviated some of the pathological changes in asthma. But parthenolide alone is not efficient as dexamethasone therapy and the parthenolide and dexamethasone combination also did not add any beneficial effect to the dexamethasone treatment.

Inundation of asthma target research: Untangling asthma riddles

Asthma is an inveterate inflammatory disorder, delineated by the airway inflammation, bronchial hyperresponsiveness (BHR) and airway wall remodeling. Although, asthma is a vague term, and is recognized as heterogenous entity encompassing different phenotypes. Targeting single mediator or receptor did not prove much clinical significant, as asthma is complex disease involving myriad inflammatory mediators. Asthma may probably involve a large number of different types of molecular and cellular components interacting through complex pathophysiological pathways. This review covers the past, present, and future therapeutic approaches and pathophysiological mechanisms of asthma. Furthermore, review describe importance of targeting several mediators/modulators and receptor antagonists involved in the physiopathology of asthma. Novel targets for asthma research include Galectins, Immunological targets, K ⁺ Channels, Kinases and Transcription Factors, Toll-like receptors, Selectins and Transient receptor potential channels. But recent developments in asthma research are very promising, these include Bitter taste receptors (TAS2R) abated airway obstruction in mouse model of asthma and Calcium-sensing receptor obliterate inflammation and in bronchial hyperresponsiveness allergic asthma. All these progresses in asthma targets, and asthma phenotypes exploration are auspicious in untangling of asthma riddles.

Novel biomarkers of resistance of pancreatic cancer cells to oncolytic vesicular stomatitis virus

Vesicular stomatitis virus (VSV) based recombinant viruses (such as VSV-ΔM51) are effective oncolytic viruses (OVs) against a majority of pancreatic ductal adenocarcinoma (PDAC) cell lines. However, some PDAC cell lines are highly resistant to VSV-ΔM51. We recently showed that treatment of VSV-resistant PDAC cells with ruxolitinib (JAK1/2 inhibitor) or TPCA-1 (IKK-β inhibitor) breaks their resistance to VSV-ΔM51. Here we compared the global effect of ruxolitinib or TPCA-1 treatment on cellular gene expression in PDAC cell lines highly resistant to VSV-ΔM51. Our study identified a distinct subset of 22 interferon-stimulated genes (ISGs) downregulated by both ruxolitinib and TPCA-1. Further RNA and protein analyses demonstrated that 4 of these genes (MX1, EPSTI1, XAF1, and GBP1) are constitutively co-expressed in VSV-resistant, but not in VSV-permissive PDACs, thus serving as potential biomarkers to predict OV therapy success. Moreover, shRNA-mediated knockdown of one of such ISG, MX1, showed a positive effect on VSV-ΔM51 replication in resistant PDAC cells, suggesting that at least some of the identified ISGs contribute to resistance of PDACs to VSV-ΔM51. As certain oncogene and tumor suppressor gene variants are often associated with increased tropism of OVs to cancer cells, we also analyzed genomic DNA in a set of PDAC cell lines for frequently occurring cancer associated mutations. While no clear correlation was found between such mutations and resistance of PDACs to VSV-ΔM51, the analysis generated valuable genotypic data for future studies.

Role of the ion channel, transient receptor potential cation channel subfamily V member 1 (TRPV1), in allergic asthma

BACKGROUND

Asthma prevalence has increased world-wide especially in children; thus there is a need to develop new therapies that are safe and effective especially for patients with severe/refractory asthma. CD4(+) T cells are thought to play a central role in disease pathogenesis and associated symptoms. Recently, TRPV1 has been demonstrated to regulate the activation and inflammatory properties of CD4(+) cells. The aim of these experiments was to demonstrate the importance of CD4(+) T cells and the role of TRPV1 in an asthma model using a clinically ready TRPV1 inhibitor (XEN-D0501) and genetically modified (GM) animals.

METHODS

Mice (wild type, CD4 (-/-) or TRPV1 (-/-)) and rats were sensitised with antigen (HDM or OVA) and subsequently topically challenged with the same antigen. Key features associated with an allergic asthma type phenotype were measured: lung function (airway hyperreactivity [AHR] and late asthmatic response [LAR]), allergic status (IgE levels) and airway inflammation.

RESULTS

CD4(+) T cells play a central role in both disease model systems with all the asthma-like features attenuated. Targeting TRPV1 using either GM mice or a pharmacological inhibitor tended to decrease IgE levels, airway inflammation and lung function changes.

CONCLUSION

Our data suggests the involvement of TRPV1 in allergic asthma and thus we feel this target merits further investigation.

Transcription Factor NF-κB: An Update on Intervention Strategies

The nuclear factor (NF)-κB family of transcription factors are ubiquitous and pleiotropic molecules that regulate the expression of more than 150 genes involved in a broad range of processes including inflammation, immunity, cell proliferation, differentiation, and survival. The chronic activation or dysregulation of NF-κB signaling is the central cause of pathogenesis in many disease conditions and, therefore, NF-κB is a major focus of therapeutic intervention. Because of this, understanding the relationship between NF-κB and the induction of various downstream signaling molecules is imperative. In this review, we provide an updated synopsis of the role of NF-κB in DNA repair and in various ailments including cardiovascular diseases, HIV infection, asthma, herpes simplex virus infection, chronic obstructive pulmonary disease, and cancer. Furthermore, we also discuss the specific targets for selective inhibitors and future therapeutic strategies.

The effect of an IκB-kinase-β(IKKβ) inhibitor on tobacco smoke-induced pulmonary inflammation

PURPOSE OF THE STUDY

Inactivation of NF-κB with IKKβ knockout mice reduces tobacco smoke-induced pulmonary inflammation. In this study, we investigated whether the IKKβ inhibitor PS-1145 could attenuate the pulmonary inflammation induced by tobacco smoke.

MATERIALS AND METHODS

We divided 30 mice into three groups: a control group, a smoking group, and a PS-1145 group. Mice from the smoking and PS-1145 groups were exposed for 2 weeks to tobacco smoke. PS-1145 was injected intraperitoneally before every tobacco smoke exposure. After 2 weeks, bronchoalveolar lavage (BAL) was performed for cell counting and measuring of inflammatory chemokines. We analyzed the correlation between NF-κB and NF-κB-regulated chemokines in BAL fluid and measured the neutrophils and macrophages by immunostaining in lung tissues.

RESULTS

The PS-1145 group showed a significant reduction in the number of total cells, neutrophils, and macrophages, as well as the KC and MCP-1 level, in the BAL fluid compared to the smoking group. There was no significant difference in the level of MIP-1α. The level of NF-κB in BAL fluid was significantly positively correlated with KC and MCP-1 levels, but not with MIP-1α level. The PS-1145 group also showed a significant fewer neutrophils and macrophages in the lung tissue.

CONCLUSIONS

We conclude that the IKKβ inhibitor PS-1145 suppressed the NF-κB signaling pathway and reduced the recruitment of inflammatory cells and chemokines in pulmonary inflammation induced by tobacco smoke. IKKβ inhibition offers a potential therapeutic target for tobacco smoke-induced pulmonary inflammation.

The role of CRAC channel in asthma

Asthma is increasing globally and current treatments only manage a proportion of patients. There is an urgent need to develop new therapies. Lymphocytes are thought to play a central role in the pathophysiology of asthma through the production of inflammatory mediators. This is thought to be via the transcription factor NFAT which in turn can be activated through Ca(2+) release-activated Ca(2+) (CRAC) channels. The aim of this work was to investigate the role of CRAC in clinical and pre-clinical models of allergic asthma. Initial data demonstrated that the NFAT pathway is increased in stimulated lymphocytes from asthmatics. To confirm a role for the channel we showed that a selective inhibitor, Synta 66, blocked mediator production from lymphocytes. Synta 66 inhibited CD2/3/28 induced IL-2, IL-7, IL-13 & IFNΥ in a concentration-dependent manner in healthy and severe asthma donors, with over 60% inhibition observed for all cytokines. NFAT pathway was also increased in a pre-clinical asthma model. In this model we have demonstrated that CRAC played a central role in the airway inflammation and late asthmatic response (LAR). In conclusion, our data provides evidence that suggests targeting CRAC channels could be of therapeutic benefit for asthma sufferers.

Breaking resistance of pancreatic cancer cells to an attenuated vesicular stomatitis virus through a novel activity of IKK inhibitor TPCA-1

Vesicular stomatitis virus (VSV) is an effective oncolytic virus against most human pancreatic ductal adenocarcinoma (PDAC) cell lines. However, some PDAC cell lines are highly resistant to oncolytic VSV-ΔM51 infection. To better understand the mechanism of resistance, we tested a panel of 16 small molecule inhibitors of different cellular signaling pathways, and identified TPCA-1 (IKK-β inhibitor) and ruxolitinib (JAK1/2 inhibitor), as strong enhancers of VSV-ΔM51 replication and virus-mediated oncolysis in all VSV-resistant PDAC cell lines. Both TPCA-1 and ruxolitinib similarly inhibited STAT1 and STAT2 phosphorylation and decreased expression of antiviral genes MxA and OAS. Moreover, an in situ kinase assay provided biochemical evidence that TPCA-1 directly inhibits JAK1 kinase activity. Together, our data demonstrate that TPCA-1 is a unique dual inhibitor of IKK-β and JAK1 kinase, and provide a new evidence that upregulated type I interferon signaling plays a major role in resistance of pancreatic cancer cells to oncolytic viruses.

Vitamin E Isoform γ-Tocotrienol Downregulates House Dust Mite-Induced Asthma

Inflammation and oxidative damage contribute to the pathogenesis of asthma. Although corticosteroid is the first-line treatment for asthma, a subset of patients is steroid resistant, and chronic steroid use causes side effects. Because vitamin E isoform γ-tocotrienol possesses both antioxidative and anti-inflammatory properties, we sought to determine protective effects of γ-tocotrienol in a house dust mite (HDM) experimental asthma model. BALB/c mice were sensitized and challenged with HDM. Bronchoalveolar lavage (BAL) fluid was assessed for total and differential cell counts, oxidative damage biomarkers, and cytokine levels. Lungs were examined for cell infiltration and mucus hypersecretion, as well as the expression of antioxidants and proinflammatory biomarkers. Sera were assayed for IgE and γ-tocotrienol levels. Airway hyperresponsiveness in response to methacholine was measured. γ-Tocotrienol displayed better free radical-neutralizing activity in vitro and inhibition of BAL fluid total, eosinophil, and neutrophil counts in HDM mouse asthma in vivo, as compared with other vitamin E isoforms, including α-tocopherol. Besides, γ-tocotrienol abated HDM-induced elevation of BAL fluid cytokine and chemokine levels, total reactive oxygen species and oxidative damage biomarker levels, and of serum IgE levels, but it promoted lung-endogenous antioxidant activities. Mechanistically, γ-tocotrienol was found to block nuclear NF-κB level and enhance nuclear Nrf2 levels in lung lysates to greater extents than did α-tocopherol and prednisolone. More importantly, γ-tocotrienol markedly suppressed methacholine-induced airway hyperresponsiveness in experimental asthma. To our knowledge, we have shown for the first time the protective actions of vitamin E isoform γ-tocotrienol in allergic asthma.

Oxidants induce a corticosteroid-insensitive phosphorylation of histone 3 at serine 10 in monocytes

Oxidative stress enhances inflammation and reduces the effectiveness of corticosteroids, but the inflammatory signalling pathways induced by oxidants remain ill-defined. Phosphorylation of histone 3 at serine 10 (H3-Pser10) marks out a subset of inflammatory genes for transcription, several of which are induced in oxidant-associated inflammation. However, the influence of oxidants or of corticosteroids on this modification remains unknown. We assessed the regulation of H3-Pser10 by oxidants and lipopolysaccharide (LPS) in human blood monocytes and lung macrophages and the effectiveness of its abolition in controlling inflammatory gene expression in cells from asthmatic subjects compared to corticosteroids alone. Both oxidants and LPS promoted the induction of H3-Pser10 which was unaffected by corticosteroids. The induction of H3-Pser10 was mediated through p38α mitogen-activated protein kinase (MAPK) and IκB kinase 2 (IKK-2) signalling. Consequently, inhibitors of p38α MAPK or IKK-2 used in combination with dexamethasone were more effective at controlling inflammatory gene expression from monocytes and lung macrophages from asthmatic patients than the corticosteroid alone. Therefore, reduction of H3-Pser10 by inhibition of p38α MAPK or of IKK-2 may provide greater anti-inflammatory control than corticosteroids alone in oxidant-associated inflammation such as severe asthma.

Receptor-interacting protein 2 gene silencing attenuates allergic airway inflammation

Persistent activation of NF-κB has been associated with the development of asthma. Receptor-interacting protein 2 (Rip2) is a transcriptional product of NF-κB activation. It is an adaptor protein with serine/threonine kinase activity and has been shown to positively regulate NF-κB activity. We investigated potential protective effects of Rip2 gene silencing using small interfering RNA (siRNA) in an OVA-induced mouse asthma model. Rip2 protein level was found to be upregulated in allergic airway inflammation. A potent and selective Rip2 siRNA given intratracheally knocked down Rip2 expression in OVA-challenged lungs and reduced OVA-induced increases in total and eosinophil counts, and IL-4, IL-5, IL-13, IL-1β, IL-33, and eotaxin levels in bronchoalveolar lavage fluid. Rip2 silencing blocked OVA-induced inflammatory cell infiltration and mucus hypersecretion as observed in lung sections, and mRNA expression of ICAM-1, VCAM-1, E-selectin, RANTES, IL-17, IL-33, thymic stromal lymphopoietin, inducible NO synthase, and MUC5ac in lung tissues. In addition, elevation of serum OVA-specific IgE level in mouse asthma model was markedly suppressed by Rip2 siRNA, together with reduced IL-4, IL-5, and IL-13 production in lymph node cultures. Furthermore, Rip2 siRNA-treated mice produced significantly less airway hyperresponsiveness induced by methacholine. Mechanistically, Rip2 siRNA was found to enhance cytosolic level of IκBα and block p65 nuclear translocation and DNA-binding activity in lung tissues from OVA-challenged mice. Taken together, our findings clearly show that knockdown of Rip2 by gene silencing ameliorates experimental allergic airway inflammation, probably via interruption of NF-κB activity, confirming Rip2 a novel therapeutic target for the treatment of allergic asthma.

Geniposide inhibits airway inflammation and hyperresponsiveness in a mouse model of asthma

Our group recently reported the strong anti-inflammatory effects of geniposide (Gen), a bioactive iridoid glucoside derived from gardenia jasminoides, in a mouse acute lung injury model. Herein, we hypothesized that Gen might also have potential therapeutic benefits in treatment of asthma, which was tested in a mouse model of ovalbumin (Ova)-induced allergic airway inflammation. Ova-sensitized and -challenged BALB/c mice, as compared with control animals, displayed airway hyperresponsiveness (AHR), bronchoalveolar lavage eosinophilia, mucus hypersecretion, and increased T help 2 (Th2)-associated cytokine and chemokine amounts, as well as serum Ova-specific immunoglobulin E (IgE) level. Being compared with the Ova-induced hallmarks of asthma, intraperitoneal Gen treatment prevented eosinophilic pulmonary infiltration, attenuated the increases in interleukin (IL)-4, IL-5, and IL-13, and reduced eotaxin and vascular cell adhesion molecule 1 (VCAM-1) expression. Also, Gen significantly ameliorated the Ova-driven airway hyperresponsiveness, mucus hypersecretion, and allergen-specific IgE level, which are the cardinal pathophysiological symptoms in allergic airway diseases. In addition, the efficacy of Gen was comparable to that of dexamethasone (Dex), a currently available anti-asthmatic drug. Collectively, our findings reveal that the development of immunoregulatory strategies based on Gen may be considered as an effective adjuvant therapy for allergic asthma.

Galangin Abrogates Ovalbumin-Induced Airway Inflammation via Negative Regulation of NF-κB

Persistent activation of nuclear factor κB (NF-κB) has been associated with the development of asthma. Galangin, the active pharmacological ingredient from Alpinia galanga, is reported to have a variety of anti-inflammatory properties in vitro via negative regulation of NF-κB. This study aimed to investigate whether galangin can abrogate ovalbumin- (OVA-) induced airway inflammation by negative regulation of NF-κB. BALB/c mice sensitized and challenged with OVA developed airway hyperresponsiveness (AHR) and inflammation. Galangin dose dependently inhibited OVA-induced increases in total cell counts, eosinophil counts, and interleukin-(IL-) 4, IL-5, and IL-13 levels in bronchoalveolar lavage fluid, and reduced serum level of OVA-specific IgE. Galangin also attenuated AHR, reduced eosinophil infiltration and goblet cell hyperplasia, and reduced expression of inducible nitric oxide synthase and vascular cell adhesion protein-1 (VCAM-1) levels in lung tissue. Additionally, galangin blocked inhibitor of κB degradation, phosphorylation of the p65 subunit of NF-κB, and p65 nuclear translocation from lung tissues of OVA-sensitized mice. Similarly, in normal human airway smooth muscle cells, galangin blocked tumor necrosis factor-α induced p65 nuclear translocation and expression of monocyte chemoattractant protein-1, eotaxin, CXCL10, and VCAM-1. These results suggest that galangin can attenuate ovalbumin-induced airway inflammation by inhibiting the NF-κB pathway.

Evaluation of glucocorticoid receptor function in COPD lung macrophages using beclomethasone-17-monopropionate

Previous studies of glucocorticoid receptor (GR) function in COPD lung macrophages have used dexamethasone to evaluate inhibition of cytokine production. We have now used the clinically relevant corticosteroid beclomethasone-17-monopropionate (17-BMP) to assess GR function in COPD lung macrophages, and investigated the transactivation of glucocorticoid sensitive genes and GR phosphorylation in addition to cytokine production. Lung macrophages were purified from surgically acquired lung tissue, from patients with COPD, smokers, and non-smokers. The transactivation of glucocorticoid sensitive genes (FKBP51 and GILZ) by 17-BMP were analysed by polymerase chain reaction. 17-BMP suppression of LPS-induced TNFα, IL-6 and CXCL8 was measured by ELISA and GR phosphorylation was measured by immunohistochemistry and Western blot. 17-BMP reduced cytokine release in a concentration dependent manner, with >70% inhibition of all cytokines, and no difference between COPD patients and controls. Similarly, the transactivation of FKBP51 and GILZ, and GR phosphorylation was similar between COPD patients and controls. In this context, GR function in COPD lung macrophages is unaltered. 17-BMP effectively suppresses cytokine production in COPD lung macrophages.

β5i subunit deficiency of the immunoproteasome leads to reduced Th2 response in OVA induced acute asthma

The immunoproteasome subunit β5i has been shown to play an important role in Th1/Th17 driven models of colitis and arthritis. However, the function of β5i in Th2 dependent diseases remains enigmatic. To study the role of β5i in Th2-driven pathology, β5i knockout (KO) and control mice were tested in different models of experimental allergic asthma. β5i-deficient mice showed reduced OVA/Alum- and subcutaneous/OVA-induced acute asthma with decreased eosinophilia in the bronchoalveolar lavage (BAL), low OVA-specific IgG1 and reduced local and systemic Th2 cytokines. While Th2 cells in the lungs were reduced, Tregs and Th1 cells were not affected. Attenuated asthma in β5i KO mice could not be attributed to defects in OVA uptake or maturation of dendritic cells in the lung. Surprisingly, β5i deficient mice developed HDM asthma which was comparable to control mice. Here, we present novel evidence for the requirement of the β5i immunosubunit to generate a strong Th2 response during OVA- but not HDM-induced acute asthma. The unexpected role of β5i in OVA asthma remains to be clarified.

1,25-dihydroxyvitamin D3 inhibits nuclear factor kappa B activation by stabilizing inhibitor IκBα via mRNA stability and reduced phosphorylation in passively sensitized human airway smooth muscle cells

Excessive activation of nuclear transcription factor-κB (NF-κB) is involved in human airway smooth muscle cells (HASMCs) activities in asthma. We investigated the effects of 1,25 - dihydroxyvitamin D3 [1,25 - (OH) 2D3] on the NF- κB signaling pathway in passively sensitized HASMCs and the molecular mechanisms involved. HASMCs were treated with either healthy controls' serum, asthma patients' serum or pretreated with 1,25 - (OH) 2D3 prior to treatment with asthmatics' serum. At 1 h after serum treatment: electrophoretic mobility shift assay (EMSA) was used to detect NF-κB DNA binding activity; immunocytochemical staining was used to observe the nuclear translocation of NF-κB p65; Western blots were used for NF-κB p65, IκBα, and phospho-IκBα protein levels and the nuclear translocation of NF-κB p65; real-time quantitative PCR was used for NF-κB p65 and IκBα mRNA expressions; and actinomycin D treatment was used to determine IκBα mRNA stability. Our major findings were: (1) 1,25 - (OH) 2D3 significantly reduced asthma serum passively sensitized HASMCs NF-κB DNA binding activity and inhibited the nuclear translocation of NF-κB p65; (2) 1,25 - (OH) 2D3 increased the stability of IκBα mRNA with reduced IκBα phosphorylation in asthma serum passively sensitized HASMCs and significantly increased IκBα expression in these HASMCs. Inhibiting NF-κB signalling with 1,25 - dihydroxyvitamin D3 may be a therapeutic approach for controlling HASMC-related remodelling in asthma.

Design of small molecules targeting transcriptional activation by NF-κB: overview of recent advances

BACKGROUND

The transcription factor NF-κB plays a central role in immune signaling and the inflammatory response. It also activates transcription of antiapoptotic factors in tumor cells, leading to enhanced cell survival. Because of the importance of NF-κB in inflammation and cancer, there is considerable interest in development of drugs that inhibit NF-κB activation or NF-κB-directed transcription. Recent elucidation of the intracellular pathways that activate NF-κB and mechanisms for transcriptional regulation by NF-κB has identified molecular targets for rational design of such drugs.

OBJECTIVE

This review provides an update on NF-κB signaling and an overview of three classes of NF-κB inhibitors: i) inhibitors of IκB kinase-β (also called IKK2), an essential link in the inflammatory response; ii) agents that react with NF-κB and prevent its binding to DNA; and iii) ligands for nuclear receptors such as the glucocorticoid receptor, PPARs and liver X receptor, which interfere with NF-κB-mediated transcription through a mechanism termed ligand-dependent transrepression. Recent progress in development of glucocorticoid receptor, PPAR and liver X receptor ligands with dissociated activity, which retain transrepression but have reduced transactivation potency, is also described.

CONCLUSIONS

NF-κB inhibitors have yielded promising results in rodent models of inflammatory disease and cancer. Some of these are currently advancing into clinical trials.

Cigarette smoke induced airway inflammation is independent of NF-κB signalling

RATIONALE

COPD is an inflammatory lung disease largely associated with exposure to cigarette smoke (CS). The mechanism by which CS leads to the pathogenesis of COPD is currently unclear; it is known however that many of the inflammatory mediators present in the COPD lung can be produced via the actions of the transcription factor Nuclear Factor-kappaB (NF-κB) and its upstream signalling kinase, Inhibitor of κB kinase-2 (IKK-2). Therefore the NF-κB/IKK-2 signalling pathway may represent a therapeutic target to attenuate the inflammation associated with COPD.

AIM

To use a range of assays, genetically modified animals and pharmacological tools to determine the role of NF-κB in CS-induced airway inflammation.

METHODS

NF-κB pathway activation was measured in pre-clinical models of CS-induced airway inflammation and in human lung tissue from COPD patients. This data was complemented by employing mice missing a functional NF-κB pathway in specific cell types (epithelial and myeloid cells) and with systemic inhibitors of IKK-2.

RESULTS

We showed in an airway inflammation model known to be NF-κB-dependent that the NF-κB pathway activity assays and modulators were functional in the mouse lung. Then, using the same methods, we demonstrated that the NF-κB pathway appears not to play an important role in the inflammation observed after exposure to CS. Furthermore, assaying human lung tissue revealed that in the clinical samples there was also no increase in NF-κB pathway activation in the COPD lung, suggesting that our pre-clinical data is translational to human disease.

CONCLUSIONS

In this study we present compelling evidence that the IKK-2/NF-κB signalling pathway does not play a prominent role in the inflammatory response to CS exposure and that this pathway may not be important in COPD pathogenesis.

Dehydroxymethylepoxyquinomicin (DHMEQ), a novel NF-kappaB inhibitor, inhibits allergic inflammation and airway remodelling in murine models of asthma

BACKGROUND

Dehydroxymethylepoxyquinomicin (DHMEQ) is a newly developed compound that inhibits nuclear factor κB activation and is reported to ameliorate animal models of various inflammatory diseases without significant adverse effects. Because nuclear factor κB is a transcription factor that plays a critical role in the pathophysiology of asthma, DHMEQ may be of therapeutic benefit in asthma.

OBJECTIVE

The purpose of this study was to evaluate the effects of DHMEQ on airway inflammation and remodelling in murine models of asthma.

METHODS

The BALB/c mice were sensitized and then challenged acutely or chronically with ovalbumin and administered DHMEQ intraperitoneally before each challenge. Inflammation of airways, lung histopathology and airway hyper responsiveness to methacholine challenge were evaluated. In addition, the effect of DHMEQ on production of cytokines and eotaxin-1 by murine splenocytes, human peripheral blood mononuclear cells and bronchial epithelial cells was investigated.

RESULTS

Airway hyper responsiveness was ameliorated in both acutely and chronically challenged models by treatment with DHMEQ. DHMEQ significantly reduced eosinophilic airway inflammation and levels of Th2 cytokines in bronchoalveolar lavage fluid in the acute model. It also inhibited parameters of airway remodelling including mucus production, peribronchial fibrosis and the expression of α-smooth muscle actin. Moreover, the production of Th2 cytokines from murine splenocytes and human peripheral blood mononuclear cells and the production of eotaxin-1 by bronchial epithelial cells were inhibited by DHMEQ.

CONCLUSIONS AND CLINICAL RELEVANCE

These results indicate that DHMEQ inhibits allergic airway inflammation and airway remodelling in murine models of asthma. DHMEQ may have therapeutic potential in the treatment of asthma.

1,25-Dihydroxyvitamin D(3) (1,25-(OH)(2)D(3)) attenuates airway remodeling in a murine model of chronic asthma

OBJECTIVES

1,25-Dihydroxyvitamin D(3) (1,25-(OH)(2)D(3)) has immune- and inflammation-modulating properties in asthma, but its possible effects on asthmatic airway remodeling remain uncertain. In this study, we investigated the effects of 1,25-(OH)(2)D(3) on airway remodeling in a murine model of chronic asthma and investigated its role in regulating nuclear factor-κB (NF-κB) activation.

METHODS

BALB/c mice were sensitized to ovalbumin (OVA) and subsequently exposed to intranasal OVA challenges for 9 weeks. Some mice also received an intraperitoneal injection of 1,25-(OH)(2)D(3) at the time of challenge. At the end of the challenge period, mice were evaluated for chronic airway inflammation and airway remodeling. Nuclear translocation of NF-κB p65 in lung tissue was examined by Western blot. Inhibitor of NF-κB alpha (IκBα) expression was determined by real-time quantitative Reverse Transcription Polymerase Chain Reaction (RT-PCR) and Western blot. Phosphorylated IκBα protein expression was also determined by Western blot.

RESULTS

1,25-(OH)(2)D(3) treatment reduced OVA-induced chronic inflammation in lung tissue and attenuated established structural changes of the airways, including subepithelial collagen deposition, goblet cell hyperplasia, and increased airway smooth muscle mass. 1,25-(OH)(2)D(3) also inhibited the nuclear translocation of NF-κB p65 in lung tissue. Concurrently, 1,25-(OH)(2)D(3) induced increased IκBα protein levels via inducing increased IκBα mRNA levels and decreased IκBα phosphorylation.

CONCLUSION

1,25-(OH)(2)D(3) could attenuate asthmatic airway remodeling and its inhibition of NF-κB activation may underlie this protective effect.

Defining critical roles for NF-κB p65 and type I interferon in innate immunity to rhinovirus

The importance of NF-κB activation and deficient anti-viral interferon induction in the pathogenesis of rhinovirus-induced asthma exacerbations is poorly understood. We provide the first in vivo evidence in man and mouse that rhinovirus infection enhanced bronchial epithelial cell NF-κB p65 nuclear expression, NF-κB p65 DNA binding in lung tissue and NF-κB-regulated airway inflammation. In vitro inhibition of NF-κB reduced rhinovirus-induced pro-inflammatory cytokines but did not affect type I/III interferon induction. Rhinovirus-infected p65-deficient mice exhibited reduced neutrophilic inflammation, yet interferon induction, antiviral responses and virus loads were unaffected, indicating that NF-κB p65 is required for pro-inflammatory responses, but redundant in interferon induction by rhinoviruses in vivo. Conversely, IFNAR1^−/− mice exhibited enhanced neutrophilic inflammation with impaired antiviral immunity and increased rhinovirus replication, demonstrating that interferon signalling was critical to antiviral immunity. We thus provide new mechanistic insights into rhinovirus infection and demonstrate the therapeutic potential of targeting NF-κB p65 (to suppress inflammation but preserve anti-viral immunity) and type I IFN signalling (to enhance deficient anti-viral immunity) to treat rhinovirus-induced exacerbations of airway diseases.

Angiotensin-(1-7) inhibits allergic inflammation, via the MAS1 receptor, through suppression of ERK1/2- and NF-κB-dependent pathways

BACKGROUND AND PURPOSE Angiotensin-(1-7) [Ang-(1-7)] has anti-inflammatory effects in models of cardiovascular disease and arthritis, but its effects in asthma are unknown. We investigated whether Ang-(1-7) has anti-inflammatory actions in a murine model of asthma. EXPERIMENTAL APPROACH The effects of Ang-(1-7) alone or in combination with the MAS1 receptor antagonist, A779, were evaluated over a 4 day period in an ovalbumin-challenged mouse model of allergic asthma. On day 5, bronchoalveolar lavage was performed, and lungs were sectioned and assessed histologically for quantification of goblet cells, perivascular and peribronchial inflammation and fibrosis. Biochemical analysis of the pro-inflammatory ERK1/2 and IκB-α was assessed. In addition, the effect of Ang-(1-7) on proliferation of human peripheral blood mononuclear cells (HPBMC) was investigated. KEY RESULTS Ang-(1-7) attenuated ovalbumin-induced increases in total cell counts, eosinophils, lymphocytes and neutrophils. Ang-(1-7) also decreased the ovalbumin-induced perivascular and peribronchial inflammation, fibrosis and goblet cell hyper/metaplasia. Additionally, Ang-(1-7) reduced the ovalbumin-induced increase in the phosphorylation of ERK1/2 and IκB-α. These effects of Ang-(1-7) were reversed by the MAS1 receptor antagonist A779. Furthermore, Ang-(1-7) inhibited phytohaemagglutinin (PHA)-induced HPBMC proliferation. CONCLUSION AND IMPLICATIONS Ang-(1-7), via its MAS1 receptor, acts as an anti-inflammatory pathway in allergic asthma, implying that activation of the MAS1 receptor may represent a novel approach to asthma therapy.

IKK biology

The inhibitor of nuclear factor-κB (IκB) kinase (IKK) complex is the master regulator of the NF-κB signaling pathway. The activation of the IKK complex is a tightly regulated, highly stimulus-specific, and target-specific event that is essential for the plethora of functions attributed to NF-κB. More recently, NF-κB-independent roles of IKK members have brought increased complexity to its biological function. This review highlights some of the major advances in the studies of the process of IKK activation and the biological roles of IKK family members, with a focus on NF-κB-independent functions. Understanding these complex processes is essential for targeting IKK for therapeutics.

Reduced cell proliferation by IKK2 depletion in a mouse lung-cancer model

Lung cancer is one of the leading cancer malignancies, with a five-year survival rate of only ~15%. We have developed a lentiviral-vector-mediated mouse model, which enables generation of non-small-cell lung cancer from less than 100 alveolar epithelial cells, and investigated the role of IKK2 and NF-κB in lung-cancer development. IKK2 depletion in tumour cells significantly attenuated tumour proliferation and significantly prolonged mouse survival. We identified Timp1, one of the NF-κB target genes, as a key mediator for tumour growth. Activation of the Erk signalling pathway and cell proliferation requires Timp-1 and its receptor CD63. Knockdown of either Ikbkb or Timp1 by short hairpin RNAs reduced tumour growth in both xenograft and lentiviral models. Our results thus suggest the possible application of IKK2 and Timp-1 inhibitors in treating lung cancer.

Fisetin, a bioactive flavonol, attenuates allergic airway inflammation through negative regulation of NF-κB

Persistent activation of nuclear factor-κB (NF-κB) has been associated with the development of asthma. Fisetin (3,7,3',4'-tetrahydroxyflavone), a naturally occurring bioactive flavonol, has been shown to inhibit NF-κB activity. We hypothesized that fisetin may attenuate allergic asthma via negative regulation of the NF-κB activity. Female BALB/c mice sensitized and challenged with ovalbumin developed airway inflammation. Bronchoalveolar lavage fluid was assessed for total and differential cell counts, and cytokine and chemokine levels. Lung tissues were examined for cell infiltration and mucus hypersecretion, and the expression of inflammatory biomarkers. Airway hyperresponsiveness was monitored by direct airway resistance analysis. Fisetin dose-dependently inhibited ovalbumin-induced increases in total cell count, eosinophil count, and IL-4, IL-5 and IL-13 levels recovered in bronchoalveolar lavage fluid. It attenuated ovalbumin-induced lung tissue eosinophilia and airway mucus production, mRNA expression of adhesion molecules, chitinase, IL-17, IL-33, Muc5ac and inducible nitric oxide synthase in lung tissues, and airway hyperresponsiveness to methacholine. Fisetin blocked NF-κB subunit p65 nuclear translocation and DNA-binding activity in the nuclear extracts from lung tissues of ovalbumin-challenged mice. In normal human bronchial epithelial cells, fisetin repressed TNF-α-induced NF-κB-dependent reporter gene expression. Our findings implicate a potential therapeutic value of fisetin in the treatment of asthma through negative regulation of NF-κB pathway.

Human pluripotent stem cells for modeling toxicity

The development of xenobiotics, driven by the demand for therapeutic, domestic and industrial uses continues to grow. However, along with this increasing demand is the risk of xenobiotic-induced toxicity. Currently, safety screening of xenobiotics uses a plethora of animal and in vitro model systems which have over the decades proven useful during compound development and for application in mechanistic studies of xenobiotic-induced toxicity. However, these assessments have proven to be animal-intensive and costly. More importantly, the prevalence of xenobiotic-induced toxicity is still significantly high, causing patient morbidity and mortality, and a costly impediment during drug development. This suggests that the current models for drug safety screening are not reliable in toxicity prediction, and the results not easily translatable to the clinic due to insensitive assays that do not recapitulate fully the complex phenotype of a functional cell type in vivo. Recent advances in the field of stem cell research have potentially allowed for a readily available source of metabolically competent cells for toxicity studies, derived using human pluripotent stem cells harnessed from embryos or reprogrammed from mature somatic cells. Pluripotent stem cell-derived cell types also allow for potential disease modeling in vitro for the purposes of drug toxicology and safety pharmacology, making this model possibly more predictive of drug toxicity compared with existing models. This article will review the advances and challenges of using human pluripotent stem cells for modeling metabolism and toxicity, and offer some perspectives as to where its future may lie.

Transient receptor potential A1 channels: insights into cough and airway inflammatory disease

Cough is a common symptom of diseases such as asthma and COPD and also presents as a disease in its own right. Treatment options are limited; a recent meta-analysis concluded that over-the-counter remedies are ineffective, and there is increasing concern about their use in children. Transient receptor potential cation channel, subfamily A, member 1 (TRPA1) channels are nonselective cation channels that are activated by a range of natural products (eg, allyl isothiocyanate), a multitude of environmental irritants (eg, acrolein, which is present in air pollution, vehicle exhaust, and cigarette smoke), and inflammatory mediators (eg, cyclopentenone prostaglandins). TRPA1 is primarily expressed in small-diameter, nociceptive neurons where its activation probably contributes to the perception of noxious stimuli. Inhalational exposure to irritating gases, fumes, dusts, vapors, chemicals, and endogenous mediators can lead to the development of cough. The respiratory tract is innervated by primary sensory afferent nerves, which are activated by mechanical and chemical stimuli. Recent data suggest that activation of TRPA1 on these vagal sensory afferents by these irritant substances could lead to central reflexes, including dyspnea, changes in breathing pattern, and cough, which contribute to the symptoms and pathophysiology of respiratory diseases.

IκB kinase β inhibitor IMD-0354 suppresses airway remodelling in a Dermatophagoides pteronyssinus-sensitized mouse model of chronic asthma

BACKGROUND

Nuclear factor (NF)-κB is a transcription factor that regulates cytokine and chemokine production in various inflammatory diseases, including bronchial asthma. IκB kinase (IKK) β is important for NF-κB activation in inflammatory conditions, and is possibly related to airway remodelling. Thus, inhibition of the IKKβ-NF-κB pathway may be an ideal strategy for the management of airway remodelling.

OBJECTIVE

We examined the effects of a newly synthesized IKKβ inhibitor, IMD-0354, in a chronic allergen exposure model of bronchial asthma in mice.

METHODS

A chronic mouse model was generated by challenge with house dust mite antigen (Dermatophagoides pteronyssinus). IMD-0354 was administrated intraperitoneally in therapeutic groups. Lung histopathology, hyperresponsiveness and the concentrations of mediators and molecules in supernatants of lung homogenates were determined.

RESULTS

NF-κB activation was inhibited by prolonged periods of IMD-0354 administration. IMD-0354 reduced the numbers of bronchial eosinophils. IMD-0354 also inhibited the pathological features of airway remodelling, including goblet cell hyperplasia, subepithelial fibrosis, collagen deposition and smooth muscle hypertrophy. Inhibition of these structural changes by IMD-0354 was the result of the suppressing the production and activation of remodelling-related mediators, such as TGF-β, via inhibition of IKKβ. IMD-0354 inhibited IL-13 and IL-1β production, and it restored the production of IFN-γ. It also ameliorated airway hyperresponsiveness.

CONCLUSION

IKKβ plays crucial roles in airway inflammation and remodelling in a chronic mouse model of asthma. A specific IKKβ inhibitor, IMD-0354, may be therapeutically beneficial for treating airway inflammation and remodelling in chronic asthma.

Immunosuppressive effects of fisetin in ovalbumin-induced asthma through inhibition of NF-κB activity

Fisetin, a flavonoid compound commonly present in fruits and vegetables, can exert anti-inflammation activities via inhibition of the NF-κB-signaling pathway. This study aims to evaluate the antiasthma activity of fisetin and investigate its possible molecular mechanisms. We found that fisetin attenuated lung inflammation, goblet cell hyperplasia, and airway hyperresponsiveness in ovalbumin-induced asthma and decreased eosinophils and lymphocytes in bronchoalveolar lavage fluid. Fisetin treatment reduced expression of the key initiators of allergic airway inflammation (eotaxin-1 and TSLP), Th2-associated cytokines (IL-4, IL-5, and IL-13) in lungs, and Th2-predominant transcription factor GATA-3 and cytokines in thoracic lymph node cells and splenocytes. Notably, fisetin treatment impaired NF-κB activation in OVA-stimulated lung tissues and TNF-α-stimulated bronchial epithelial cells. Collectively, this study demonstrated the beneficial effect of fisetin in the amelioration of asthmatic phenotypes. The antiasthma activity of fisetin is associated with reduction of Th2 responses as well as suppression of NF-κB and its downstream chemokines.

Treatment of allergic asthma: modulation of Th2 cells and their responses

Atopic asthma is a chronic inflammatory pulmonary disease characterised by recurrent episodes of wheezy, laboured breathing with an underlying Th2 cell-mediated inflammatory response in the airways. It is currently treated and, more or less, controlled depending on severity, with bronchodilators e.g. long-acting beta agonists and long-acting muscarinic antagonists or anti-inflammatory drugs such as corticosteroids (inhaled or oral), leukotriene modifiers, theophyline and anti-IgE therapy. Unfortunately, none of these treatments are curative and some asthmatic patients do not respond to intense anti-inflammatory therapies. Additionally, the use of long-term oral steroids has many undesired side effects. For this reason, novel and more effective drugs are needed. In this review, we focus on the CD4+ Th2 cells and their products as targets for the development of new drugs to add to the current armamentarium as adjuncts or as potential stand-alone treatments for allergic asthma. We argue that in early disease, the reduction or elimination of allergen-specific Th2 cells will reduce the consequences of repeated allergic inflammatory responses such as lung remodelling without causing generalised immunosuppression.