Targeted HAS2 Expression Lessens Airway Responsiveness in Chronic Murine Allergic Airway Disease.

Broadly, my research focuses on the role for G protein-coupled receptors in the pathophysiology of asthma. Asthma is a complex disease characterized by airway inflammation, hyperresponsiveness and remodeling. G protein-coupled receptors figure largely in the pathology and treatment of this disease. For example, beta-agonists, the rescue medication inhaled by asthmatics, act at airway smooth muscle beta2-adrenergic receptors (β2-AR) to relax the airways. However, excessive use of beta-agonists has been associated with clinical worsening of asthma control and increased mortality. β2-ARs can signal through two well characterized and independent signaling pathways; a G protein-dependent pathway and a beta-arrestin-dependent pathway. Previously we showed that mice lacking beta-arrestin-2 do not develop the symptoms of allergic airway inflammatory disease and that T cell and eosinophil migration to the lung is impaired in these mice. Similarly, others have shown that the asthma phenotype is significantly reduced in mice lacking global expression of β2-ARs. Thus, we hypothesize that the beta-arrestin-dependent signaling arm, downstream of the β2-AR, is responsible for promoting the asthma phenotype. The translational relevance of this work is high given that the determination of the signaling pathway that is utilized by β2-ARs can be influenced by the molecular signature of the agonist. Thus, our work could lead to the discovery of a β2-AR ligand that bronchodilates the airways without promoting asthma symptoms. In addition to transducing β2-AR-mediated signaling to promote asthma, we hypothesize that beta-arrestin-2 also mediates chemokine receptor signaling and thus, the inflammatory component of asthma. Chemokines, released in response to allergens, dictate the migration of immune cells to the lung in asthma and chemokine receptors are known to signal via both the G-dependent and beta-arrestin-dependent pathways.

Dr. Ingram's research interests focus on the study of airway remodeling in human asthma. Proliferation, migration, and invasion of airway fibroblasts are key features of airway remodeling that contribute to diminished lung function over time. Dr. Ingram uses molecular biology approaches to define the effects of interleukin-13 (IL-13), a cytokine abundantly produced in the asthmatic airway, in the human airway fibroblast. She has identified important regulatory functions of several proteins prevalent in asthma that control fibroblast growth and pro-fibrotic growth factor production in response to IL-13. By understanding these pathways and their role in human asthma and the chronic effects of airway remodeling, novel treatment strategies may be developed.