Targeting kinases in asthma

Anti-oxidant and Anti-inflammatory Effects of Aquatic Exercise in Allergic Airway Inflammation in Mice

Oxidative stress and inflammation are key pathways responsible for the pathogenesis of asthma. Aquatic exercise (AE) has been proven to elicit a variety of biological activities such as anti-oxidant and anti-inflammatory effects. However, although proper forms of AE provide beneficial health effects, incorrect forms and types of AE are potentially injurious to health. Several studies have investigated AE, but the relationship between types of AE and asthma has not been fully elucidated. This study evaluated the effects of two types of AE according to resistance on ovalbumin (OVA)-induced allergic airway inflammation in mice. BALB/c mice were subjected to OVA sensitization and challenge, and then to different types of AE including, walking and swimming, in a pool filled with water to a height of 2.5 and 13 cm for 30 min, respectively. AE reduced OVA-induced eosinophilic inflammation, airway hyperresponsiveness, and serum immunoglobulin E level. AE significantly inhibited increases in interleukin (IL)-4, IL-5, IL-13, histamine, leukotriene D4, and tryptase levels in bronchoalveolar lavage fluid (BALF). AE also effectively suppressed mucus formation, lung fibrosis, and hypertrophy of airway smooth muscle within the lung tissues. This exercise markedly reduced the levels of malondialdehyde while increased glutathione and superoxide dismutase (SOD) activity in lung tissues. Furthermore, AE significantly decreased tumor necrosis factor-α, IL-6 levels, and prostaglandin E2 production in BALF. The inhibitory effects of swimming on the levels of biomarkers related to oxidative stress and inflammation were greater than that of walking. These effects may have occurred through upregulation of NF-E2-related factor 2/heme oxygenase-1 signaling and suppression of mitogen-activated protein kinase/nuclear factor-κB pathway. Cumulative results from this study suggest that AE might be beneficial in mitigating the levels of biomarkers related to oxidative stress and inflammation. Thus, this therapy represents a crucial non-pharmacological intervention for treatments of allergic airway inflammation.

Spleen Tyrosine Kinase as a Target Therapy for Pseudomonas aeruginosa Infection

Spleen tyrosine kinase (SYK) is a nonreceptor tyrosine kinase which associates directly with extracellular receptors, and is critically involved in signal transduction pathways in a variety of cell types for the regulation of cellular responses. SYK is expressed ubiquitously in immune and nonimmune cells, and has a much wider biological role than previously recognized. Several studies have highlighted SYK as a key player in the pathogenesis of a multitude of diseases. Pseudomonas aeruginosa is an opportunistic gram-negative pathogen, which is responsible for systemic infections in immunocompromised individuals, accounting for a major cause of severe chronic lung infection in cystic fibrosis patients and subsequently resulting in a progressive deterioration of lung function. Inhibition of SYK activity has been explored as a therapeutic option in several allergic disorders, autoimmune diseases, and hematological malignancies. This review focuses on SYK as a therapeutic target, and describes the possibility of how current knowledge could be translated for therapeutic purposes to regulate the immune response to the opportunistic pathogen P. aeruginosa.

Functional roles of Syk in macrophage-mediated inflammatory responses

Inflammation is a series of complex biological responses to protect the host from pathogen invasion. Chronic inflammation is considered a major cause of diseases, such as various types of inflammatory/autoimmune diseases and cancers. Spleen tyrosine kinase (Syk) was initially found to be highly expressed in hematopoietic cells and has been known to play crucial roles in adaptive immune responses. However, recent studies have reported that Syk is also involved in other biological functions, especially in innate immune responses. Although Syk has been extensively studied in adaptive immune responses, numerous studies have recently presented evidence that Syk has critical functions in macrophage-mediated inflammatory responses and is closely related to innate immune response. This review describes the characteristics of Syk-mediated signaling pathways, summarizes the recent findings supporting the crucial roles of Syk in macrophage-mediated inflammatory responses and diseases, and discusses Syk-targeted drug development for the therapy of inflammatory diseases.

Novel drug targets for asthma and COPD: lessons learned from in vitro and in vivo models

Asthma and chronic obstructive pulmonary disease (COPD) are highly prevalent respiratory diseases characterized by airway inflammation, airway obstruction and airway hyperresponsiveness. Whilst current therapies, such as β-agonists and glucocorticoids, may be effective at reducing symptoms, they do not reduce disease progression. Thus, there is a need to identify new therapeutic targets. In this review, we summarize the potential of novel targets or tools, including anti-inflammatories, phosphodiesterase inhibitors, kinase inhibitors, transient receptor potential channels, vitamin D and protease inhibitors, for the treatment of asthma and COPD.

Blockade of Syk ameliorates the development of murine sclerodermatous chronic graft-versus-host disease

BACKGROUND

Murine sclerodermatous chronic graft-versus-host disease (Scl-cGVHD) is a model for human Scl-cGVHD and systemic sclerosis (SSc). Syk is expressed in most of hematopoietic cells, fibroblasts, and endothelial cells. Syk is a protein tyrosine kinase that has an important role in transmitting signals from a variety of cell surface receptors.

OBJECTIVE

This study aims to investigate the effect of R788 (fostamatinib sodium), an oral prodrug that is rapidly converted to a potent inhibitor of Syk, R406, on Scl-cGVHD.

METHODS

R788 was orally administered twice a day to allogeneic recipients from day 14 to day 42 after bone marrow transplantation (BMT). In vitro, proliferation of GVHD-derived CD4(+) T cells and CD11b(+) cells was analyzed by R406.

RESULTS

Allogeneic BMT increased Syk phosphorylation in T, B, and CD11b(+) cells. The administration of R788 attenuated severity and fibrosis of Scl-cGVHD. The elevated expressions of CXCR4 on T cells, B cells, and CD11b(+) cells were significantly down-regulated by R788 treatment. R788 reduced memory CD4(+) T cells (CD44(hi)CD62L(-)CD4(+)). R406 inhibited proliferation of GVHD CD4(+) T cells and CD11b(+) cells in vitro. In addition, R788 treatment, inhibited proliferation of CD11b(+) cells in Scl-cGVHD mice. R788 treatment also reduced skin mRNA expressions of MCP-1, MIP-1α, IFN-γ, IL-13, IL-17A, and TGF-β1, but not influenced RANTES, CXCL12, and TFN-α.

CONCLUSION

Blockade of Syk suppressed migration factor of immune cells and antigen-specific memory CD4(+) T cells and proliferation and activation of GVHD CD4(+) T cells and CD11b(+) cells. The current studies suggested that Syk inhibitor is a potential candidate for use in treating patients with Scl-cGVHD and SSc.

Inhibitors of switch kinase 'spleen tyrosine kinase' in inflammation and immune-mediated disorders: a review

Spleen tyrosine kinase (Syk), a member of Syk family of non-receptor protein tyrosine kinases plays a significant role in the immune cell signaling in B cells, mast cells, macrophages and neutrophils. Anomalous regulation of this kinase can lead to different allergic disorders and antibody-mediated autoimmune diseases such as rheumatoid arthritis, asthma, psoriasis and allergic rhinitis. Being involved in the growth and survive mechanism of B cells, its inhibition can be beneficial in B-cell lymphoma. Thus, Syk can be sited as a therapeutically relevant target for various allergic and autoimmune disorders. This review article describes the structure of Syk and its role in B-cell signaling. In addition to this, data regarding small molecule inhibitors of Syk has also been reviewed from different papers and patents published.

Fluorescent biosensors - probing protein kinase function in cancer and drug discovery

One of the challenges of modern biology and medicine is to visualize biomolecules in their natural environment, in real-time and in a non-invasive fashion, so as to gain insight into their physiological behavior and highlight alterations in pathological settings, which will enable to devise appropriate therapeutic strategies. Fluorescent biosensors constitute a class of imaging agents which have provided major insights into the function and regulation of enzymes in their cellular context. GFP-based reporters and genetically-encoded FRET biosensors, have been successfully applied to study protein kinases in living cells with high spatial and temporal resolution. In parallel, combined efforts in fluorescence chemistry and in chemical biology have enabled the design of non-genetic, polypeptide biosensors coupled to small synthetic fluorescent probes, which have been applied to monitor protein kinase activities in vitro and in more complex biological samples, with an equally successful outcome. From a biomedical perspective, fluorescent biosensor technology is well suited to development of diagnostic approaches, for monitoring disease progression and for evaluating response to therapeutics. Moreover it constitutes an attractive technology for drug discovery programs, for high content, high throughput screening assays, to assess the potency of new hits and optimize lead compounds, whilst also serving to characterize drugs developed through rational design. This review describes the utility and versatility of fluorescence biosensor technology to probe protein kinases with a specific focus on CDK/cyclin biosensors we have developed to probe abundance, activity and conformation. This article is part of a Special Issue entitled: Inhibitors of Protein Kinases (2012).

Short-term roxithromycin treatment attenuates airway inflammation via MAPK/NF-κB activation in a mouse model of allergic asthma

OBJECTIVE

We investigated whether roxithromycin reduces ovalbumin-specific allergic asthma symptoms in mice, and we further investigated the inhibitory mechanism of roxithromycin in ovalbumin-specific allergic asthma.

METHODS

Mice were divided into five groups (n = 10 for each): control group, roxithromycin-treated groups (5, 20 and 40 mg/kg) and ovalbumin-challenged group. We measured the recruitment of inflammatory cells into the bronchoalveolar lavage fluid (BALF) or the lung tissues by Kwik-Diff and hematoxylin and eosin (H&E) staining, goblet cell hyperplasia by alcian blue-periodic acid-Schiff (AB-PAS) staining, airway hyperresponsiveness (AHR) by whole-body plethysmograph chamber, cytokine and immunoglobulin E (IgE) levels by ELISA, and the activation of mitogen-activated protein (MAP) kinases and nuclear factor-kappa B (NF-κB) in the lung tissues by Western blotting.

RESULTS

Treatment with roxithromycin resulted in fewer inflammatory cells in the BALF and peribronchial areas, and decreased AHR, goblet cell hyperplasia, IgE levels and inflammatory cytokines, as well as MAP kinases and NF-κB activation, which are increased in lung tissues of mice with ovalbumin-induced allergic asthma.

CONCLUSIONS

Our data suggest that oral administration of roxithromycin suppresses ovalbumin-induced airway inflammation and AHR by regulating the inflammatory cytokines via MAP kinases/NF-κB pathway in inflammatory cells. Based on these results, we suggest that roxithromycin may be used as a therapeutic agent for allergy-induced asthma.

Applications of molecular imaging

Today molecular imaging technologies play a central role in clinical oncology. The use of imaging techniques in early cancer detection, treatment response, and new therapy development is steadily growing and has already significantly impacted on clinical management of cancer. In this chapter, we overview three different molecular imaging technologies used for the understanding of disease biomarkers, drug development, or monitoring therapeutic outcome. They are (1) optical imaging (bioluminescence and fluorescence imaging), (2) magnetic resonance imaging (MRI), and (3) nuclear imaging (e.g., single-photon emission computed tomography (SPECT) and positron emission tomography (PET)). We review the use of molecular reporters of biological processes (e.g., apoptosis and protein kinase activity) for high-throughput drug screening and new cancer therapies, diffusion MRI as a biomarker for early treatment response and PET and SPECT radioligands in oncology.

Small animals models for drug discovery

There has been an explosion of studies of animal models of asthma in the past 20 years. The elucidation of fundamental immunological mechanisms underlying the development of allergy and the complex cytokine and chemokines networks underlying the responses have been substantially unraveled. Translation of findings to human asthma have been slow and hindered by the varied phenotypes that human asthma represents. New areas for expansion of modeling include virally mediated airway inflammation, oxidant stress, and the interactions of stimuli triggering innate immune and adaptive immune responses.

Novel molecular imaging platform for monitoring oncological kinases

Recent advances in oncology have lead to identification of a plethora of alterations in signaling pathways that are critical to oncogenesis and propagation of malignancy. Among the biomarkers identified, dysregulated kinases and associated changes in signaling cascade received the lion's share of scientific attention and have been under extensive investigations with goal of targeting them for anti-cancer therapy. Discovery of new drugs is immensely facilitated by molecular imaging technology which enables non-invasive, real time, dynamic imaging and quantification of kinase activity. Here, we review recent development of novel kinase reporters based on conformation dependent complementation of firefly luciferase to monitor kinase activity. Such reporter system provides unique insights into the pharmacokinetics and pharmacodynamics of drugs that modulate kinase signaling and have a huge potential in drug discovery, validation, and drug-target interactions.

Spleen tyrosine kinases: biology, therapeutic targets and drugs

Spleen tyrosine kinase (Syk) is an intriguing protein tyrosine kinase involved in signal transduction in a variety of cell types, and its aberrant regulation is associated with different allergic disorders and antibody-mediated autoimmune diseases such as rheumatoid arthritis, asthma and allergic rhinitis. Syk also plays an important part in the uncontrolled growth of tumor cells, particularly B cells. For these reasons, Syk is considered one of the most interesting biological targets of the last decade, as proved by the great number of papers and patents published, and the possibility of treating these pathologies by means of Syk kinase inhibitors has led to a great interest from the pharmaceutical and biotech industry.

Celastrol suppresses allergen-induced airway inflammation in a mouse allergic asthma model

Celastrol has anti-inflammatory and immunomodulatory activities, but its anti-allergic effects remain poorly understood. Therefore, we aimed to investigate the ability of celastrol to inhibit asthmatic reactions in a mouse allergic asthma model. BALB/c mice were sensitized and challenged with ovalbumin to induce asthma. We measured the recruitment of inflammatory cells into the bronchoalveolar lavage fluid or lung tissues by Diff-Quik and hematoxylin and eosin staining, respectively, goblet cell hyperplasia by periodic acid-Schiff (PAS) staining, airway hyperresponsiveness by Flexvent system, mRNA and protein expression of cytokines, matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) by reverse transcriptase polymerase chain reaction and ELISA, respectively, and the activities of mitogen-activated protein (MAP) kinases and nuclear factor-kappa B (NF-kappaB) in the bronchoalveolar lavage cells and lung tissues by Western blot and electrophoretic mobility shift assay (EMSA), respectively. Celastrol reduced the total number of inflammatory cells in the bronchoalveolar lavage fluid and in peribronchial areas, and decreased the airway hyperresponsiveness, mRNA and protein expression levels for inflammatory cytokines such as interleukin (IL)-4, IL-13, TNF-alpha and IFN-gamma, and for MMPs and TIMPs, MAP kinases and NF-kappaB activities in the bronchoalveolar lavage cells and in the lung tissues increased in ovalbumin-induced allergic asthma in mice. Our data suggest that oral administration of celastrol suppresses ovalbumin-induced airway inflammation, hyperresponsiveness, and tissue remodeling by regulating the imbalance of MMP-2/-9 and TIMP-1/-2 by inflammatory cytokines via MAP kinases/NF-kappaB in inflammatory cells. Based on our findings, we suggest that celastrol may be used as a therapeutic agent for allergy-induced asthma.

Molecular imaging of protein kinases

Protein kinases are important regulators of signal-transduction pathways. Dysregulated kinase activity is observed in a variety of human diseases such as cancer, making them targets for the development of molecular therapies. Identification of new drugs is greatly aided by molecular imaging tools which enable real time, non-invasive, dynamic and quantitative imaging of kinase activity in vivo. We have recently described a new reporter platform based on conformation dependent complementation of firefly luciferase to monitor serine/threonine kinase (Akt) activity. The reporter system provides unique insights into the pharmacokinetics and pharmacodynamics of drugs that modulate kinase activity in living subjects and also provide a platform for cell based high-throughput drug screening for modulators of kinase activity.

Syk inhibitors as treatment for allergic rhinitis

Allergic rhinitis is characterized by a hypersensitive immune response in the upper airways to seasonal or perennial allergens leading to episodes of sneezing, itching, runny nose and nasal congestion. These symptoms are mainly the manifestations of a large number of mediators released by mast cells and basophils localized in the nasal mucosa, following their activation via allergen-specific immunoglobulin E (IgE) receptors. Current medications antagonize the action of distinct mediators such as histamine and leukotrienes for symptom relief, or block the production of pro-inflammatory cytokines to suppress allergic inflammation. Notably, rather than neutralizing individual mediators, Syk kinase inhibitors can block the allergen-induced release of all mast cell mediators and the production of most eicosanoids and cytokines. Thus, Syk kinase represents an attractive therapeutic target for acute and chronic allergic inflammation. Syk kinase inhibitors are now entering clinical trials. Using cell-based structure-activity relationships with primary human mast cells, a series of 2,4-diaminopyrimidine Syk kinase inhibitors was developed. One of these compounds, referred to as R112, exhibited suitable characteristics for intranasal delivery and was tested for safety and efficacy in allergic rhinitis patients. In a park environment, R112 showed remarkable amelioration of acute allergic rhinitis symptoms with rapid onset of action. These results demonstrate the clinical significance of inhibiting Syk in allergic upper airway disorders.

Anti-inflammatory mechanism of simvastatin in mouse allergic asthma model

Statins have anti-inflammatory property and immunomodulatory activity. In this study we aimed to investigate the inhibitory mechanism of simvastatin in allergic asthmatic symptoms in mice. BALB/c mice were sensitized and challenged by ovalbumin to induce asthma. Ovalbumin-specific serum IgE levels were measured by enzyme-linked immunosorbent assay (ELISA), and the recruitment of inflammatory cells into bronchoalveolar lavage fluid or lung tissues was measured by Diff-Quik staining and hematoxylin and eosin (H&E) staining, respectively, the expressions of CD40, CD40 ligand (CD40L), and vascular cell adhesion molecule-1 (VCAM-1) by immunohistochemistry, the mRNA and protein expressions of cytokines in lung tissues by reverse transcriptase-polymerase chain reaction (RT-PCR) or ELISA, epithelial hyperplasia by periodic acid-Schiff (PAS) staining, activities of matrix metalloproteinases (MMPs) by zymography, the activities of small G proteins, mitogen-activated protein (MAP) kinases and nuclear factor-kappa B (NF-kappaB) in bronchoalveolar lavage cells and lung tissues by western blot and EMSA, respectively. Simvastatin reduced ovalbumin-specific IgE level, the number of total inflammatory cells, macrophages, neutrophils, and eosinophils into bronchoalveolar lavage fluid, the expressions of CD40, CD40L or VCAM-1, the mRNA and protein levels of interleukin (IL)-4, IL-13 and tumor necrosis factor (TNF)-alpha, the numbers of goblet cells, activities of MMPs, and further small G proteins, MAP kinases and NF-kappaB activities in bronchoalveolar lavage cells and lung tissues increased in ovalbumin-induced allergic asthma in mice. Our data suggest that simvastatin may be used as a therapeutic agent in asthma, based on reductions of various allergic responses via regulating small G proteins/MAP kinases/NF-kappaB in mouse allergic asthma.