Awardees and Abstracts

2014 Awardees

Scholar Awards

Alix Ashare, M.D., Ph.D.
Dartmouth College
Medicine
Mechanisms of Increased Asthma Severity Secondary to Polymorphisms in the ACE Gene
Heart failure and high blood pressure are commonly treated with drugs that block an enzyme called ACE (angiotensin converting enzyme). ACE generates a protein called angiotensin II, which in turn constricts blood vessels, thereby raising blood pressure. Recent studies have shown that angiotensin II not only raises blood pressure but also activates inflammation. Dr. Ashare has preliminary evidence that this occurs in the lungs, where specialized cells produce angiotensin II, leading to inflammation. She notes that this takes on added significance in light of genetic studies indicating that asthma severity correlates with genetic sequences near the ACE gene. While the ACE gene itself is responsible for the production of ACE, Dr. Ashare proposes that the RNA products of nearby genetic sequences regulate levels of ACE. She will test this hypothesis through the study of human cells. This is an example of a risky study (the hypothesis may be wrong) with a high payoff (because drugs are available to control the activity of ACE). Direct studies of human cells, rather than animal models, are important because the mechanisms regulating ACE are likely to be species-specific Scientific Abstract
Martin D. Burke, M.D., Ph.D.
University of Illinois, Urbana-Champaign
Chemistry
Probing the Role of Lipid Peroxidation in the Pathogenesis of Asthma
During inflammation, several types of white blood cells produce oxygen in a form that is highly reactive and therefore toxic to neighboring cells. These “reactive oxygen” molecules alter the fats (lipids) in cell membranes, generating chemicals that propogate inflammation and tissue injury. The effects of reactive oxygen are difficult to block, but Dr. Burke has a new approach. He has synthsized a chemical called peridinin, which is highly effective in blocking reactive oxygen – more than ten times more effective than the next best chemical. Peridin was first discovered in single-cell organisms caused dinoflagellates, which cause the “red tide” and thrive in environments of extreme oxidative stress, Dr. Burke proposes to study the effects of peridinin on mouse models of asthma and then to examine its effects on human lung cells grown in the laboratory, including lung cells from patients who have decreased resistance to reactive oxygen. Dr. Burke’s ability to synthesize substantial quantities of peridin gives him an unusual opportunity to develop a new approach to blocking inflammation and tissue damage in the airways. Although he is less than 10 years out of his training as an MD/PhD, he is already a Professor at the University of Illinois, reflecting his unusual talent as a chemist and as an investigator. Scientific Abstract
Jan E. Carette, Ph.D.
Stanford University
Microbiology and Immunology
Unbiased Discovery of Novel Host Genes Critical for Rhinovirus: Towards Antiviral Therapy for Asthma
Asthma is made worse by viral infections, and the most common culprit is the type of virus that causes the “common cold,” i.e., rhinovirus. There are no vaccines developed against rhinoviruses, because there are too many of them and they easily mutate. Viruses, however, cannot replicate without help from the human cells that they infect. Dr. Carette therefore proposes to define the human proteins that are necessary for rhinoviruses to multiply, with the idea that these could be targets for the prevention of viral spread. He will begin by screening thousands of cells that have each lost one or more genes, looking for reduction in the growth of virus. Lower viral growth could mean that the missing genes are required for viral replication. Having identified these genes, he will study the mechanisms of their effect on viral growth. He will also look specifically for the role of genes that are indirectly activated by viruses. These broad approaches increase the likelihood of success of this project, which is of particular importance to asthma in that viruses not only make asthma worse in the short term, but also increase the long-term susceptibility to asthma when they infect children. Scientific Abstract
Xinzhong Dong, Ph.D.
Johns Hopkins University
Neuroscience
The Role of an Itch Receptor in Airway Constriction and Asthma
The sensation of itching is caused by specialized nerves in the skin. Dr. Dong has shown that these same nerves exist in the lungs, and he has studied a protein on the surface of the nerves that initiates the sensation of itching. He proposes that in the lungs this protein, which he calls the “itch receptor,” leads not only to a sensation of itching (which is common in asthma) but also to tightening of the airway muscles, constricting the airways (a central feature of asthma). To test this, he will expose lung nerves in mice to substances that engage the itch receptor, and he will assess the effects on airway constriction. He will also study nerves in mice with asthma to see if they have increased levels of itch receptors and, if so, if this makes the nerves more likely to cause airway constriction. Finally, he will study molecules that inhibit the itch receptor, testing whether these improve asthma in mice. Dr. Dong has pioneered studies of the itch receptor, but this will be his first study of their role in lungs. If the studies are successful, they will open a new pathway in the pathophysiology of asthma.  Scientific Abstract
Taku Kambayashi, M.D., Ph.D.
University of Pennsylvania
Pathology and Laboratory Medicine
The Role of Diacylglycerol Kinase in Asthma
Diacylglycerol (DAG) is a small lipid molecule that forms part of the membrane surrounding all mammalian cells. Under resting conditions, this molecule sits on the inside surface of the membrane, where it is chemically linked to another molecule called IP3. Under certain conditions, IP3 is released into the cell, leaving DAG in the cell membrane. The accumulation of DAG triggers diverse cell activities, until it is chemically modified by enzymes called DAG kinases. Dr. Kambayashi has evidence that one DAG kinase in particlar, DAG kinaseζ, is linked to asthma, because mice lacking DAG kinaseζ are resistant to asthma. These mice experience less inflammation, and airway constriction is notably reduced. Dr. Kambayashi therefore proposes that lack of DAG kinaseζ not only reduces the inflammatory response in asthma but also the underlying constrictive-response of the airways themselves. With a series of experiments in mice, he will assess the relative effects of DAG kinaseζ on inflammation and on airway constriction. He will then test the effects of deleting DAG kinaseζ at different times during the progression of asthma in mice. Finally, he will test the effect of inhibitors of DAG kinaseζ on asthma in mice and airway constriction in tissue slices obtained from human lung explants. This is the first study by anyone to test the role of DAG kinaseζ in asthma and the studies thus have the potential to identify an important new target that may act both on inflammatory asthma and on non-inflammatory asthma. Scientific Abstract
John D. MacMicking, Ph.D.
Yale University
Microbial Pathogenesis
IFN-inducible GBPs in Asthma Resolution
In most patients with asthma, lung inflammation continues even between attacks of troubled breathing. Dr. MacMicking asks why the inflammation does not subside. He proposes that the type of inflammation seen in patients with asthma may be controlled by interferon (IFN)-inducible proteins including a new family related proteins found on both immune and non-immune cells, called guanylate binding proteins (GBPs). To test this hypothesis, he has made several different mouse strains which each lack a specific GBP family member. He will first examine the resolution of inflammation in these GBP-deficient mice following the induction of asthma. Thereafter he will create mouse models that selectively lack GBPs in different immune and pulmonary cells, rather than throughout the entire host, in order to identify where the GBPs confer the effects on asthmatic inflammation. With this information in hand, he will focus even further down, testing the molecular pathways inside cells by which GBPs act to resolve asthmatic inflammation. Dr. MacMicking is a biochemical immunologist with considerable expertise relevant to these studies, but his prior research has been in the area of host defense to infectious diseases. If his hypothesis is correct, that GBPs may be important in the resolution of inflammation in asthma, this will promote a new way of thinking about treating asthma, and his experiments will help to identify novel targets for therapy. Scientific Abstract
Booki Min, Ph.D., D.V.M.
Cleveland Clinic
Immunology
IL-27-stimulated Foxp3+ Tregs, a Novel Treg Therapy to Treat Asthma
Quis custodiet ipsos custodes? – who will guard the guardians? Even as the immune response protects us against infection, it needs to be regulated so that it does not spin out of control. The immune system does this in part by maintaining a police force of immune cells whose function is to contain the immune response. These cells are called T regulatory cells, or “Tregs.” A deficiency of Tregs leads to autoimmunity and protracted inflammation. An idea that autoimmunity and/or chronic inflammation might be treatable by increasing levels of Tregs is being formulated to test in various inflammatory diseases. Specifically, Dr. Min has studied the means to enhance Treg function. He has focused on a protein called interleukin-27 (IL-27) and has shown that it enhances the suppressive power of Tregs. To examine the role of IL-27 in asthma, he will study mice in which their Tregs are unresponsive to IL-27. Conversely, he will stimulate Tregs with IL-27 in vitro and then test their ability to suppress asthma in mice. Finally, he will define the mechanisms by which IL-27 activates Tregs, seeking to identify targets that could enhance the Treg response as a therapy for asthma. This approach would have the potential advantage of working even after asthma is well established. Scientific Abstract
Philipp M. Neithammer, Ph.D.
Memorial Sloan Kettering Cancer Center
Cell Biology
Understanding ATP-mediated Remodeling of a Physiological Epithelium
There is increasing evidence that the lungs of asthmatic patients may have alterations even prior to inflammation or other observable features of asthma. In particlar, asthma may be preceded by changes in the functions of the cells that line the airways (epithelial cells), and these changes then instigate immune and inflammatory changes in the lungs. Further, as asthma progresses, the airway epithelial cells become chronically injured, and they must repair themselves as part of the healing of asthma. To study the repair of epithelial cells, Dr. Niethammer has chosen an unusual but powerful model, injury to the tail of the zebrafish, which will allow him to study cell repair in intact epithelial tissue, combining imaging, genetics, and chemistry. He demonstrates in his application that the pathways in zebrafish epithelial tissue repair are relevant to human lung epithelia. The model has the advantage that it can be used to screen potential drugs directed at any molecular targets identified. The studies are testimony to the universality of biology, and how diverse areas of investigation can be brought to bear on asthma. Scientific Abstract
Robert Tarran, Ph.D.
University of North Carolina at Chapel Hill
Cell Biology and Physiology
Does SPLUNC1 Deficiency Lead to Airways Hyperresponsiveness in Asthma?
The airway lining cells (epithelial cells), as well as some of their neighboring cells, normally produce a protein called SPLUNC1. Until recently, little was known about this protein, but work by Dr. Tarran and others has revealed that SPLUNC1 is important in maintaing watery airway fluid with minimal inflammation. This helps keep normal lungs free from mucus. In cystic fibrosis, SPLUNC1 is non-functional, leading to thickened secretions and problems clearing infections. In preliminary studies, Dr. Tarran finds that SPLUNC1 is reduced in the sputum of patients with allergic asthma as well as in the nasal secretions of patients with allergic rhinitis. In a mouse model of asthma, he finds that treatment of mice with SPLUNC1 prevents airway constriction, even when it is given after allergy and inflammation are well established – evidence that loss of SPLUNC1 is not simply a result of asthma but is, instead, a cause. He proposes to define the mechanisms by which SPLUNC1 is reduced in asthma and the mechanisms by which SPLUNC1 blocks asthma symptoms. Dr. Tarran’s proposal is unusual in that a natural product is shown to be a potential therapy for asthma, recalling the findings of Jonathan Stamler (2003 AAF Awardee) that the natural small molecule GSNO suppresses asthma. Dr. Tarran’s studies will elucidate the best mechanisms for sustaining SPLUNC1 in asthma Scientific Abstract

Extension Award

John S. McMurray, Ph.D.
University of Texas MD Anderson Caner Center
Experimental Therapeutics
Stat6 Inhibitors for the Treatment of Asthma
Asthma is associated with a distinct type of immunity, called a “Th2” immune response. Although a variety of cells and proteins are involved in this response, one molecular pathway is shared by both immune cells and airway cells in promoting a Th2 response. Dr. McMurray has been studying this pathway, looking for ways to block it. He has focused on a protein inside immune cells, called Stat6, which plays a central role in activating the asthmatic immune response. He has designed a series of potential drugs that can enter the cell and block the activity of Stat6. The results have been impressive. One of the drugs can block asthma in mice when it is administered into the airways. Importantly, it can reverse established changes in the mouse asthma model. For example, it reverses the asthma-related expansion in the number and size of cells that produce mucus. Further, Dr. McMurray has shown that related drugs block Stat6 in human cells. To advance these drugs as therapies in humans, he must first make further detailed observations in mice. He will define the lowest levels at which drugs are effective, determine the distribution and metabolism of the drug in lungs and in other mouse organs, examine the drugs for systemic effects on immunity, and look for other evidence of toxicity in mice. These are important steps in moving from the impressive asthma-blocking results in mice to the testing of a drug in humans. Scientific Abstract

2014 Awards Project Abstracts

Alix Ashare, M.D., Ph.D. — 2014 Scholar Award

Dartmouth College

Mechanisms of Increased Asthma Severity Secondary to Polymorphisms in the ACE Gene

Our goal is to investigate angiotensin converting enzyme (ACE) activity as a key risk factor in asthma, leveraging mechanistic insights as a basis for improved therapies. Patients with asthma are plagued by chronic inflammation. Lung macrophages (LMs) are critical to the local inflammatory response. Inflammation in asthma causes bronchospasm, which can result in localized hypoxia. Hypoxia, in turn, causes increased angiotensin II (ANGII), a key inflammatory mediator generated by ACE. We found that LMs generate hypoxia-induced inflammation that is blocked by an ANGII receptor (AT1) blocker. Studies have identified a deletion polymorphism (D/D) in an intron of the ACE gene that causes increased ACE and is associated with asthma severity. We found increased membrane ACE on LMs from D/D subjects. The mechanism is unknown, but our data suggest that the deleted sequence encodes microRNAs, small RNAs that regulate proteins. Based upon these data, our central hypothesis is that the ACE D/D genotype increases ACE translation, leading to an exaggerated ANGII response during hypoxia, and thus increasing the severity of asthma. In Aim 1, we will determine the impact of the ACE D/D genotype on hypoxia-induced inflammation in asthma. In Aim 2, we will define the mechanism underlying the effect of the ACE D/D genotype on ACE levels in the asthmatic lung. These studies will define the role of ACE in modulating the severity of lung inflammation, and determine if AT1 receptor blockers may be useful anti-inflammatory agents in asthma, repurposing medications that are widely used to treat other conditions.

Martin D. Burke, M.D., Ph.D. — 2014 Scholar Award

University of Illinois, Urbana-Champaign

Probing the Role of Lipid Peroxidation in the Pathogenesis of Asthma

Lipid peroxidation may represent an important and pharmacologically addressable pathway to pathogenesis in asthma, however, this hypothesis has long remained unverified. We will employ an exceptionally potent small molecule antilipoperoxidant, peridinin, recently discovered in our lab as a probe to test this hypothesis. The current model proposes that lipid peroxidation, resulting from reactive oxygen species (ROS) released by inflammatory leukocytes, leads to the formation of electrophilic breakdown products and pro-inflammatory signaling molecules. Thus, a normally innocuous irritant initiates a self-propagating pathway of lipid peroxidation that helps drive asthma pathophysiology. In search of exceptional antilipoperoxidants, we recently completed the first stereocontrolled total synthesis of the highly complex carotenoid peridinin, a difficult to isolate natural product produced by the “red tide” dinoflagellate that thrives despite extensive exposure to ROS. Furthermore, we discovered that peridinin is an order of magnitude more potent than astaxanthin, the current gold standard for carotenoid antilipoperoxidants. To our knowledge, this makes peridinin the most potent antilipoperoxidant discovered to date. We herein propose to test the role of lipid peroxidation in asthma pathophysiology via completion of two specific aims. First, we will use peridinin to block lipid peroxidation in mouse models of acute and chronic asthma and determine whether the asthmatic responses are attenuated. Second, we will use peridinin to block lipid peroxidation in bronchial epithelial and smooth muscle cells to probe its role in asthma pathophysiology. These studies will determine the importance of lipid peroxidation in asthma pathogenesis and may enable a therapeutic strategy for addressing this disease.

Jan E. Carette, Ph.D. — 2014 Scholar Award

Stanford University

Unbiased Discovery of Novel Host Genes Critical for Rhinovirus: Towards Antiviral Therapy for Asthma

The goal of our research is to use genome-wide, loss-of-function screens to identify novel human proteins that are essential for productive rhinoviral infection. These human proteins are potential targets for anti-viral therapy. Rhinovirus, a member of the Picornaviridae, is strongly associated with asthma exacerbations. Wheezing-associated illness with rhinovirus in infants is the most important risk factor for asthma development later in life. It is unclear whether rhinovirus-induced tissue damage directly causes these effects or if it is an effect of an aberrant (innate) immune response. Rhinovirus infection triggers activation of interferon-stimulated genes, but the role of only a few of these genes is well understood. New antivirals against rhinovirus would likely limit severity of respiratory distress in asthmatic individuals. This proposal aims to identify proteins critical to rhinovirus infection or critical to the innate immune response triggered by infection. Aim 1. Genome-wide knockout screens in human cells to identify genes required for rhinoviral entry and replication. Aim 2. Validation and mechanistic studies to characterize candidate human genes used by rhinovirus. Aim 3. Systematic probing of the role of each interferon-stimulated gene in the context of rhinoviral infection using CRISP/CAS9 technology. Results of the study will elucidate a distinct subset of genes that are crucial for rhinoviral infection or the host response to infection. This will provide valuable clues to host-pathogen interactions by rhinovirus. Importantly, these proteins provide new targets for drugs that can be tested for anti-rhinoviral activity and possibly used for treatment of infected individuals suffering from asthma.

Xinzhong Dong, Ph.D. — 2014 Scholar Award

Johns Hopkins University

The Role of an Itch Receptor in Airway Constriction and Asthma

An itchy throat is a common symptom of asthma. Itch in the skin and airway is initiated by sensory neurons in dorsal root and vagal ganglion, respectively. Interestingly, sensory neurons in both ganglion share many similarities, expressing the same group of receptors and channels and responding to the same type of stimuli. Therefore, the concurrence of asthma and itch suggest they may share common molecular signaling components, such as receptors and ligands. Recently, we identified members of the G protein coupled receptor family Mrgprs including MrgprC11 as novel itch receptors. Our preliminary data show that MrgprC11 is specifically expressed in vagal nerves innervating the airway and may play a role in bronchoconstriction, a hallmark feature of asthma. We therefore hypothesize that MrgprC11 in the vagal ganglion plays an important role in airway constriction and inhibition of its human ortholog MrgprX1 is a promising way to treat asthma. The proposal will further characterize the role of MrgprC11 in an asthma model. First, we will investigate whether Bam8-22, an endogenous peptide ligand for MrgprC11, evokes airway constriction in naïve and sensitized mice. Second, we will determine whether MrgprC11 and Bam8-22 are upregulated and if MrgprC11+ neurons become hyperactive after airway sensitization. Third, we will test whether the small molecule antagonists of human MrgprX1 can block airway constriction in sensitized mice. Since Mrgprs are only expressed in vagal nerves and DRG and not in other tissues, MrgprX1 antagonists may represent a new family of therapeutics to treat asthma with limited side effects.

Taku Kambayashi, M.D., Ph.D. — 2014 Scholar Award

University of Pennsylvania

The Role of Diacylglycerol Kinase in Asthma

Asthma is a respiratory disease characterized by Th2 airway inflammation with concomitant increases in mucus production and smooth muscle contraction, leading to airway obstruction. Inhibition of both inflammatory and structural components of the asthma response is needed for optimal control of asthma symptoms. Our preliminary data identify diacylglycerol kinase (DGK)ζ, an intracellular enzyme that regulates the diacylglycerol signaling pathway, as a novel target in asthma. Airway hyperresponsiveness in a mouse model of allergic asthma was abolished in DGKζ-deficient mice compared to wildtype mice. In addition to a reduction in Th2 inflammation, our data suggest that DGKζ deficiency protects against asthma also by affecting structural components. Thus, we hypothesize that the inhibition of DGKζ will block the asthmatic airway response by affecting function of both hematopoietic and structural cells in the airway. Specific Aim 1 outlines experiments that will test the role of hematopoietic and non-hematopoietic cell types that are responsible for the attenuated airway response in DGKζ deficiency. Moreover, we will specifically investigate how DGKζ deficiency might affect T cell, eosinophil, mast cell, type II pneumocyte, and smooth muscle cell function during asthma. The second aim will test the potential of DGK inhibition for the treatment of asthma using genetic and pharmacological approaches. Enzymes such as DGKs represent an attractive therapeutic target, because of the potential of small molecule inhibitors to block the active site of these enzymes. The experiments laid out in this proposal will help determine whether DGK serves as a novel target for asthma treatment.

John D. MacMicking, Ph.D. — 2014 Scholar Award

Yale University

IFN-inducible GBPs in Asthma Resolution

Non-resolving inflammation is now widely acknowledged as a major driver of disease. Implicit in this discovery is that chronic disorders which fail to abate reinforce the importance of understanding resolution in those that do. For asthma, an ostensibly “self-limiting” disease with both acute and chronic endotypes, the process of resolution remains poorly understood. Here we focus on three members of a new IFN-inducible GTPase superfamily that dominates the Th1 transcriptional profile during resolution of experimental allergen challenge in the lung. As such they could promote control over Th2-induced asthmatic inflammation to aid its abatement. These proteins belong to group of 65-73kDa immune GTPases -- the Guanylate Binding Proteins (GBPs) -- widely expressed in immune and non-immune cells with activities relevant for asthma. Recent genetic evidence show they are critical for IFN-γ-induced defense against inhaled pathogens and stimulate inflammasome assembly that may feed-forward to elicit Th1 responses via IL-18-dependent IFN-γ production. We will test their involvement in asthma resolution by challenging newly-generated Gbp1-/-, Gbp2-/- and Gbp5-/- mice with natural and experimental allergens. Here they may impact T-cell, macrophage, mucosal and mast cell responses. Mechanisms of action will be dissected in situ and in primary cell cultures where GBP mutants coupled with high-resolution imaging and reporter-based probes should uncover new points of Th1 control during asthma. Such knowledge could serve as a basis to therapeutically uncouple the protective from pathologic effects of IFN-γ signaling to alleviate asthmatic inflammation.

John S. McMurray, Ph.D. — 2014 Extension Award

University of Texas MD Anderson Caner Center

Stat6 Inhibitors for the Treatment of Asthma

Aberrant IL-4/IL-13/IL4-Rα/STAT6 signaling plays a key role in asthma pathology resulting in mucus production, airway hyperresponsiveness (AHR), eosinophil and other inflammatory cell recruitment, and immunoglobulin class switching to IgE. Upon cytokine binding, signal transducer and activator of transcription 6 (STAT6) transmits signals directly from IL-4Rα to the nucleus and transcribes genes that underlie expression of asthma-like disease. To block this pathway, our laboratory is developing small-molecule, cell-permeable phosphopeptide mimetic prodrugs that target the SH2 domain of STAT6. Our lead inhibitor, PM-242H, when administered intranasally (50 µg/dose), inhibited STAT6 phosphorylation and the development of AHR, Th2 cell recruitment to the lung, eosinophilia, and goblet cell metaplasia in an Aspergillus-induced allergic lung disease model. More importantly, in established disease, AHR was reversed accompanied by reduced goblet cell metaplasia and no increase in fungal burden, demonstrating that inhibition of STAT6 phosphorylation is potentially an ideal treatment modality for asthma. Next generation compounds inhibit STAT6 phosphorylation in human airway cells (IC50 ~100 nM) and are selective for STAT6 over STAT1, STAT3, STAT5, PI3K, and Src. Of the new inhibitors, PM-43I inhibited the development of disease at 0.5 µg doses, a 100-fold gain in potency. To demonstrate the feasibility of these compounds as potential asthma therapeutics, the aims are: (1) Evaluate ability of lower doses of PM-43I to inhibit induction and reverse established disease. (2) Perform lung and plasma pharmacokinetics. (3) Evaluate toxicity of PM-43I and monitor potential immune suppression distal from the lung, evaluating molecular markers such as serum IgE and lung pSTAT levels.

Booki Min, Ph.D., D.V.M. — 2014 Scholar Award

Cleveland Clinic

IL-27-stimulated Foxp3+ Tregs, a Novel Treg Therapy to Treat Asthma

Foxp3+ regulatory CD4 T cells (Treg) play an indispensable role in regulating immunity and tolerance. Defects in Treg generation and/or function are directly associated with uncontrolled lymphoproliferative diseases, including allergic pathology; thus indicating that Tregs are important regulators in Th2 mediated inflammation. However, the precise mechanisms that Tregs express to regulate Th2 immunity remain unclear. There is growing evidence that Treg function is defective in patients with allergic disease. Treg infusion therapy has thus been conceptualized and being tested to treat inflammatory diseases. Yet, Tregs tend to lose optimal suppressor function under inflammatory conditions, limiting the clinical applicability of Treg therapy. Therefore, identifying a pathway(s) that enhances Treg function is of vital importance. From the preliminary studies we found that IL-27 signaling in Foxp3+ Tregs is essential for suppressor function and that Tregs prestimulated with IL-27 exhibit greater suppressor function. The main hypothesis is that IL-27 induced during allergic inflammation optimizes Treg suppressor function. We also propose that suppressor function of Tregs is enhanced by IL-27 pre-stimulation, attenuating ongoing inflammation in the lung. Two specific aims are proposed to test the hypothesis. Aim 1 will determine if IL-27 signaling in Tregs is essential for suppressor function during allergic inflammation. Aim 2 will examine a cellular mechanism by which IL-27 controls Treg suppressive function during allergic inflammation. The success of these studies will have an immediate impact on the development of novel approaches that improve the efficacy of Treg therapy in treatment of asthma.

Philipp M. Neithammer, Ph.D. — 2014 Scholar Award

Memorial Sloan Kettering Cancer Center

Understanding ATP-mediated Remodeling of a Physiological Epithelium

Epithelial barrier defects and remodeling are hallmarks of asthmatic airway disease. Epithelial defects are evident before excessive inflammation can be observed, and are not completely reversed by anti-inflammatory treatment. Since asthma may originate from an epithelial rather than an immunological dysfunction, causative asthma therapies should not only target inflammation, but also epithelial barrier defects and aberrant repair responses. However, physiological repair mechanisms of wet epithelia remain largely unclear. Cell culture studies have implicated ATP as an important mediator of epithelial repair in vitro, but its in vivo role has been rarely studied. Extracellular ATP is pathologically increased in asthmatic lungs. Our preliminary data show that too much ATP triggers aberrant epithelial remodeling in vivo. Therapeutically, extracellular ATP could be modulated in two ways, by blocking ATP secretion, or blocking its action on cell surface receptors. Progress on the first approach has been hindered by lack of physiological knowledge of the secretory mechanism. In Aim 1, we propose to address this problem in the context of an in-vivo epithelium using the powerful zebrafish tail fin microinjury assay. Progress on the second approach has been hindered by lack of knowledge of relevant receptors. Most studies suggest that extracellular ATP exerts its physiological effects via P2X and P2Y receptors. However, antagonists of these families have had little impact on asthma treatment. Based on our preliminary data, we propose that an alternative, more disease- relevant receptor exists that mediates epithelial remodeling in vivo. In Aim 2, we suggest experiments to identify this receptor.

Robert Tarran, Ph.D. — 2014 Scholar Award

University of North Carolina at Chapel Hill

Does SPLUNC1 Deficiency Lead to Airways Hyperresponsiveness in Asthma?

Short palate, lung and nasal epithelium clone 1 (SPLUNC1) is the most abundant gene in polarized airway epithelia and is present at high levels in normal airway surface liquid (ASL). We and others have shown that SPLUNC1 levels are significantly reduced in murine airway epithelium exposed to a Th2 cytokine milieu. In this proposal, we demonstrate that ASL SPLUNC1 levels are diminished in allergic asthmatic patients as compared to healthy control subjects. The role of SPLUNC1 in modulating airway allergic inflammation remains unknown. However, we have now found that SPLUNC1 is secreted serosally from human airway epithelia and that SPLUNC1 prevents airway hyperresponsiveness in house dust mite (HDM)-challenged mice. In this proposal, we will (i) determine how SPLUNC1 is decreased in asthmatics and HDM-exposed mice: (ii) determine which region/domain of SPLUNC1 modulates smooth muscle contraction and (iii) identify how SPLUNC1 prevents airway hyperresponsiveness. These specific aims will enable us to test the hypothesis that SPLUNC1 is an epithelial-derived factor that directly modulates airway smooth muscle contractility. Furthermore, data obtained in this grant will enable us to develop SPLUNC1, or SPLUNC1-derived peptides as a novel therapy to prevent airway hyperresponsiveness in asthma.