Contraction and proliferation are two important functions of airway smooth muscle (ASM), and dysregulation of these functions is believed to be important in the pathogenesis of asthma. G protein-coupled receptors (GPCRs) are known to be important regulators of ASM function, capable of either promoting (Gq-coupled GPCRs) or inhibiting (Gs-coupled GPCRs) ASM contraction and proliferation. We propose to characterize how these competing classes of GPCRs desensitize when exposed to their cognate agonists, and determine whether specific inhibition of desensitization of the Gs-coupled receptor (2-adrenergic receptor can render the most common asthma therapy, beta-agonist, a more effective antagonist of ASM contraction and proliferation. We will employ state of the art biochemical, molecular, and genetic approaches to characterize the specificity of various mutant inhibitory constructs of GPCR kinases (GRKs) for both Gq- and Gs- coupled GPCRs, and establish the effectiveness of these constructs in regulating receptor signaling and associated functional consequences.
Aims 1 and 2 will use both human and murine ASM cell cultures to determine the effect of GRK regulatory domain peptides or mutants, and siRNA-mediated GRK knockdown, on cellular signaling events important to ASM contraction and proliferation.
Aim 3 will determine the functional consequences of this regulation by assessing changes in ASM contraction (both in vivo and ex vivo) and proliferation. The proposed studies will identify for the first time how desensitization mechanisms preferentially influence competitive GPCR signaling events in ASM and link this regulation to functional outcomes. Results from these studies will establish the potential usefulness of targeting GRK-mediated desensitization mechanisms as a therapy for obstructive airway diseases: Relevance to Public Health: The proposed studies will test whether the (2-adrenergic receptor is the receptor in airway smooth muscle most prone to desensitization mechanisms that cause a loss of responsiveness, and examine whether a novel strategy to selectively block this desensitization could improve the beneficial effects of (-agonist therapy for asthma.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1-RES-C (02))
Program Officer
Banks-Schlegel, Susan P
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Maryland Baltimore
Schools of Medicine
United States
Zip Code
Billington, Charlotte K; Penn, Raymond B; Hall, Ian P (2017) ?2 Agonists. Handb Exp Pharmacol 237:23-40
Singh, Jagmohan; Mohanty, Ipsita; Addya, Sankar et al. (2017) Role of differentially expressed microRNA-139-5p in the regulation of phenotypic internal anal sphincter smooth muscle tone. Sci Rep 7:1477
Singh, Jagmohan; Boopathi, Ettickan; Addya, Sankar et al. (2016) Aging-associated changes in microRNA expression profile of internal anal sphincter smooth muscle: Role of microRNA-133a. Am J Physiol Gastrointest Liver Physiol 311:G964-G973
Forkuo, Gloria S; Kim, Hosu; Thanawala, Vaidehi J et al. (2016) Phosphodiesterase 4 Inhibitors Attenuate the Asthma Phenotype Produced by ?2-Adrenoceptor Agonists in Phenylethanolamine N-Methyltransferase-Knockout Mice. Am J Respir Cell Mol Biol 55:234-42
Pera, Tonio; Penn, Raymond B (2016) Bronchoprotection and bronchorelaxation in asthma: New targets, and new ways to target the old ones. Pharmacol Ther 164:82-96
Chan, Tung O; Zhang, Jin; Tiegs, Brian C et al. (2015) Akt kinase C-terminal modifications control activation loop dephosphorylation and enhance insulin response. Biochem J 471:37-51
Penn, Raymond B (2015) Physiology. Calcilytics for asthma relief. Science 348:398-9
Pera, Tonio; Hegde, Akhil; Deshpande, Deepak A et al. (2015) Specificity of arrestin subtypes in regulating airway smooth muscle G protein-coupled receptor signaling and function. FASEB J 29:4227-35
Romero, Freddy; Shah, Dilip; Duong, Michelle et al. (2015) A pneumocyte-macrophage paracrine lipid axis drives the lung toward fibrosis. Am J Respir Cell Mol Biol 53:74-86
Penn, Raymond B (2014) Far from ""disappointing"". Am J Respir Crit Care Med 189:360

Showing the most recent 10 out of 24 publications