Asthma is a chronic inflammatory airway disease with a central component of hyper-reactive bronchial smooth muscle (BSM). Asthma in children is linked to allergy and viral infection and often persists into adulthood. Although it has long been speculated that allergen insults to the developing lung result in prolonged changes in lung structure and function, the molecular nature and precise mechanisms underlying these changes are unknown. We propose to investigate changes along the BSM-nerve axis that occur in childhood asthma and are linked to persistent airway dysfunction in the adult. Our focus rests on an established concept that the crosstalk between the target and innervating nerve plays a critical role in shaping phenotypes of both tissues. Using a mouse model of childhood asthma, we find that BSM innervation is increased after early-life allergen insult through up-regulation of neurotrophin 4 (NT4). We further find that such alterations are critically associated with BSM hyper-reactivity later in life. These findings lead to our hypothesis: allergen insult to the developing neonatal lung aberrantly alters the nerve-BSM crosstalk, and resulting increase in NT4-dependent BSM innervation causes persistent BSM hyper-reactivity in the adulthood. To test our hypothesis, we will: Aim 1. Characterize allergen-induced increase in BSM innervation in the neonates and persistence into adulthood. Aim 2. Establish the functional link between increased BSM innervation to persistent BSM hyper-reactivity using both gain- and loss-of NT4 function mouse models. This work will help identify new therapeutic targets and pathways to improve asthma treatment and outcome.

The asthmatic lung is heavily infiltrated by a diversity of immune cells including lymphocytes, eosinophils, basophils and macrophages and many of these cells release mediators involved in asthma pathogenesis. However, the chemoattractants most crucial for attraction of each inflammatory cell type, and for the retention of cells after they have arrived, are incompletely defined. We recently identified a role for a novel G-protein coupled receptor, EBI2, and its oxysterol ligand 7α,25-dihydroxycholesterol, in guiding movements of activated B cells required for mounting plasma cell responses. EBI2 is highly expressed by Th2 cells, eosinophils and basophils, EBI2-ligand is abundant within the lung and an enzyme involved in EBI2-ligand synthesis is upregulated in allergen-exposed lungs. Here we propose to explore the role of EBI2 and the enzymes required for EBI2-ligand synthesis in the inflammation-induced pathogenesis of asthma using mouse models. IgE plays an important role in asthma and we will also test whether EBI2-deficiency affects induction of IgE plasma cell responses. These studies will provide insight into the role of a novel class of intercellular signaling lipid in asthma pathogenesis.

Asthma is a disease that results in airway hyperresponsiveness, a condition of enhanced sensitivity of airways to physical and chemical stimuli resulting in excessive and prolonged narrowing. While the role of airway smooth muscle (ASM) cells in normal lung function is not clear, it appears to have several consequences in asthmatic airways including enhancing rate and extent of airway constriction and preventing airway relaxation. In asthmatic patients, this constriction can occur even in the absence of an airway inflammatory response. As such, several successful asthma treatments target ASM, but the regulation of ASM contractility is not clear. A highly dynamic actin cytoskeleton is also thought to underlie the plasticity of smooth muscle cells. However, the cytoskeletal dynamics involved in smooth muscle contraction have not been characterized. We propose experiments to quantitatively evaluate the regulation of cytoskeletal dynamics during smooth muscle cell contraction. These studies will establish understanding of the basic molecular mechanisms regulating the mechanical behaviors of smooth muscle cells that will provide insight into the design of novel therapeutic treatments of asthma.

In order to develop new therapies to manage asthma there is a need to better understand the pathogenesis of the clinical spectrum associated with this condition. Indeed, the combination of genetics and experimental models has led to a better understanding of the cellular and soluble mediators that are involved in allergic inflammation and this has been critical for the identification of new targets that are amenable to small-molecule and biological interventions. One approach to managing immune mediated inflammation is to take advantage of natural regulatory pathways that normally limit inflammation or promote wound healing. Work from this laboratory and others have identified the heterodimeric cytokine IL-27 (composed of p28 and EBI3) as having a role in limiting Th1, Th2 and Th17 responses and there is now a literature that it can promote T cell production of IL-10. Moreover, the use of genome-wide linkage studies and candidate gene association has linked polymorphisms in the IL-27p28 sub-unit with susceptibility to IBD, COPD and asthma. Together, these observations provide a strong rationale for studying clinical material and basic models to understand the impact of IL-27 in asthma and studies are proposed to understand whether IL-27 represents a viable approach to managing asthma.

The interaction of IgE antibodies with the high affinity receptor, FceRI, plays a central role in initiating allergic reactions associated with asthma. The IgE-receptor interaction has been targeted for treatment of allergic diseases and several IgE ligands have been identified as high affinity inhibitors of IgE-receptor binding. However, among these IgE inhibitors, only the anti-IgE antibody (Xolair) is an approved therapeutic drug for the treatment of moderate to severe persistent asthma. The anti-IgE antibody directly binds to free IgE to block IgE:FceRI interactions, so this therapeutic strategy will not disrupt an ongoing allergic response triggered by preformed IgE-receptor complexes. No small molecule inhibitors of IgE:FceRI binding have been identified and fully validated, but these could offer significant clinical advantages over anti-IgE treatment. We have developed two complementary fluorescence assays to follow IgE binding to its receptor, a fluorescence quenching (FQ) assay and a time-resolved fluorescence resonance energy transfer (TR-FRET) assay. We have demonstrated that the TR-FRET assay is suitable for high-throughput screening (HTS) by performing a pilot screen of the NIH clinical collection library. The specific goal of this extension proposal is to conduct a large high throughput screen for small molecule inhibitors and to validate potential hits using a comprehensive set of biochemical and cell-based assays. We are seeking this extension support to identify a chemically diverse panel of lead compounds for the treatment of allergic asthma, using new research tools developed during our primary AAF award.

Asthma is a common chronic inflammatory disorder of the airways, characterized by recurring episodes of wheezing, coughing, and shortness of breath, whose precise etiology is as yet not understood. There is increasing evidence to support a role for epigenetic mechanisms in the etiology of common, chronic non-Mendelian disease phenotypes. The overall goal of this study is to test the hypothesis that epigenetic mechanisms are associated with asthma using cutting-edge methylomic and transcriptomic profiling methods in longitudinal samples of asthma-discordant (and asthma-concordant) monozygotic (MZ) twins, in conjunction with a powerful replication strategy. Our specific aims are to 1) undertake a systematic survey of epigenomic variation in a longitudinally-assessed population-based sample of asthma-discordant MZ twins; 2) relate asthma-associated differentially methylated regions (DMRs) with genetic, transcriptomic, immunological and environmental data obtained from the same longitudinally-assessed cohort of twin samples; 3) replicate asthma-associated DMRs in independent sample collections; and 4) comprehensively profile genome-wide patterns of allele-specific DNA methylation (ASM) in MZ twins discordant for asthma, and across the different cell- and tissue-types implicated in asthma. Epigenetic data will be combined with environmental, genetic, transcriptomic, and proteomic data to enable a truly integrative approach to disease etiology.

The differentiation of T helper (Th) cell subsets is controlled by small group of lineage-determining transcription factors, whose expression can be stabilized or repressed by epigenetic modifications to chromatin depending on the cellular context. As certain Th cell-lineage regulate the immune pathology associated with asthma we will use our expertise in understanding the molecular regulation of immune cell function to identify the epigenetic pathways responsible for stabilizing the phenotype of asthma promoting Th cells. In support of this proposal we found that either gene deletion or pharmacological inhibition of the histone methyl transferase, Suv39h1, results in reduced stability of the Th2 phenotype in vitro and attenuated asthma pathology in vivo. Based on this preliminary data we hypothesize that specifically modulating the stability of the epigenome in asthma-inducing Th lymphocytes will improve asthma outcomes. To test this hypothesis we aim to; 1) Characterize the epigenetic pathways that stabilize the Th cell phenotypes responsible for promoting allergic asthma. We will use mice lacking specific epigenetic modifiers to examine which components are important for Th cell phenotypic stability in vitro and in vivo using next-generation sequencing technologies. 2) Examine how asthma responses are affected in the absence of specific epigenetic components. We will investigate the asthmatic responses of mice deficient for a range of epigenetic regulators. 3) Target epigenetic pathways with inhibitors to destabilize asthma-promoting Th cells. We will use specific small molecule inhibitors to investigate how blocking certain classes of histone modifications will impact on asthma pathology in vivo.

Asthma is a disorder of the airways that currently affects more than 300 million people worldwide and it is predicted that this number will grow considerably over the next decade. Although the initial molecular events underlying allergic asthma are becoming clear, there is a growing appreciation that chronic asthma involves major remodelling of the airways, particularly of airway epithelia. Much clinical data supports the notion that the severity of chronic asthma correlates tightly with the extent of airway remodelling. Respiratory epithelial cells proliferate and secrete growth factors (which drive the remodelling programme) in response to a rise in cytoplasmic Ca2+ concentration. The latter occurs following opening of Ca2+ channels in the plasma membrane. We have discovered that the epithelial Ca2+ channel is the store-operated CRAC channel, and Ca2+ entry through these channels leads to recruitment of the Ca2+-dependent transcription factor NFAT, gene expression and cell proliferation. Block of the CRAC channel abolishes NFAT activation. The CRAC channel therefore provides a novel and attractive therapeutic target for managing chronic asthma. In this proposal, we will identify the molecular components of the epithelial CRAC channel, and how it leads to gene expression and airway remodelling. The outcome of this research proposal should therefore trigger serious consideration for the prescription of CRAC channels blockers for managing asthma in the clinic.

5-Oxo-ETE is the most potent eosinophil chemotactic factor among lipid mediators. Its actions are mediated by the selective OXE receptor (OXE-R). Its potent effects on eosinophil migration suggest it may play a role in allergic asthma, one of the hallmarks of which is the infiltration of eosinophils into the lungs. Eosinophilic inflammation in asthma is associated with airway narrowing and remodeling. For these reasons, OXE-R is an attractive therapeutic target. As there are no known selective OXE-R antagonists, our group has designed and synthesized two excellent OXE-R antagonists active in the 6-9 nM range. This study will take advantage of a preclinical feline model of asthma because cats, unlike mice or rats, possess an ortholog of OXER1 and because they are the only animal species that spontaneously develop allergic asthma with all of the major features of the human disease. A summary of the specific aims are as follows: 1)To determine the in vitro potency of the selective OXE-Rs 1 and 2 and their S stereoisomers on 5-oxo-ETE-induced activation of feline eosinophils. 2)To investigate their pharmacokinetics following oral administration to cats. 3)To measure 5-oxo-ETE concentrations in bronchoalveolar lavage fluid (BALF) from experimentally asthmatic cats following allergen challenge. 4)To determine whether either 1 or 2 in vivo can reduce airway inflammation and/or airway hyperresponsiveness following allergen challenge of sensitized cats.

Asthma, a major health problem world-wide, is characterized by expiratory airflow limitation, chronic inflammation, structural and functional changes of airways. With AAF support we have shown that aldose reductase (AR) inhibitors such as fidarestat are effective in preventing eosinophils infiltration, Th2 cytokines and chemokines increase, mucus secretion, airway resistance and IL-13-induced metaplasia in Ova- and RWE-induced acute airway inflammation in cultured cells and mouse models of asthma. Our results obtained from animal studies strongly support that AR inhibitors could be used as anti-asthmatic drugs. However, prior to clinical trial of an AR inhibitor, fidarestat, it would be necessary to examine ex vivo efficacy of this inhibitor in clinical samples obtained from mild to severe asthma patients. Therefore, our aim is to examine the efficacy of fidarestat in the prevention of immune response in lung brushings and BALF obtained from normal, mild, moderate and severe allergic asthma patients. Specifically, we will perform pre-clinical studies using lung biopsies, lung brushings and BALF obtained from normal, mild, moderate and allergic asthma patients to determine if fidarestat prevents the activation of inflammatory responses mediated by signalosome and inflammasome axis. The Completion of these studies should help us in transferring our results from bench-to-bed as they will create the awareness needed for NIH and pharmaceutical companies to invest in our future phase-II clinical studies testing fidarestat as a novel anti-asthma drug.

While many improvements in therapies for asthma have occurred, asthma continues to be associated with significant morbidity, excessive mortality, and high healthcare costs. Multiple hypotheses regarding asthma pathogenesis exist, but abnormal airway smooth muscle (ASM) function and airway narrowing are central to these pathways. We recently made CF pigs that lack the cystic fibrosis transmembrane conductance regulator (CFTR) - the Cl–/-HCO3–channel that is abnormal in humans with cystic fibrosis (CF). An unanticipated finding was that CF pigs have narrowed airways and abnormal ASM function. These data are very exciting and suggest that CFTR might play an important role in ASM biology. Interestingly, up to 50% of humans with CF have airway hyper-responsiveness, which is often present before the onset of infection or inflammation. A critical knowledge gap regarding CFTR and ASM function exists. We hypothesize that CFTR is required for normal ASM function and may represent a novel therapeutic target in asthma. To test this hypothesis we propose the following Specific Aims: #1 - Identify the mechanism of CFTR function in airway smooth muscle. #2 - Understand the contribution of CFTR to airway hyper-responsiveness in an asthma model. Our current asthma therapies are limited and new therapeutic targets are urgently needed. We will investigate readily available pharmacological approaches to enhance CFTR in an asthma model. We will use our expertise in airway disease and CFTR biology to hopefully accelerate discovery and have a significant impact on patient care and therapeutics development in asthma.