Development and Characterization of PI3Kg/PKA Peptide Disruptors as New Therapeutic Tools for the Treatment of Obstructive Airway Diseases
Type: dissertation
Abstract: Progressive obstructive airway diseases, including asthma, chronic obstructive pulmonary disease, and the genetic disorder cystic fibrosis (CF), represent a major health burden worldwide.Cyclic AMP (cAMP) elevating agents, like β2-adrenergic receptor agonists and phosphodiesterase inhibitors, are a mainstay in the treatment of these conditions, but their clinical use is limited by unwanted side effects due to global cAMP elevation.Compartment-restricted cAMP modulation can be achieved by manipulating the function of A-kinase anchoring proteins (AKAPs) which anchor protein kinase A (PKA) to its substrates and regulators, including enzymes involved in cAMP generation and destruction, in specific cellular locations.For instance, blocking the AKAP activity of phosphoinositide 3-kinase γ (PI3Kγ) has been identified as a strategy to improve lung function by inducing cAMP-mediated bronchorelaxation, ion transport and antiinflammatory responses.This study focuses on the development and the characterization of PI3Kγ/PKA peptide disruptors as valuable tools for manipulating β2-AR/cAMP signaling in the lungs for the treatment of chronic obstructive airway diseases.We characterized the aerodynamic properties of a PI3Kg mimetic peptide (MP) that we previously demonstrated being effective in the airway tract of mice upon intratracheal administration, where it safely boosts airway cAMP without altering cAMP homeostasis in organs in which its elevation would not be desirable, such as in the heart.Here we found that this compound has favourable proteolytic stability, mucus permeability and aerodynamic behaviour that confirm the possibility of using this preclinical advanced compound for inhaled therapy of all pulmonary conditions where local cAMP elevation is desirable, including but not limited to COPD and CF.In parallel, we report the generation of a novel non-natural peptide, DRI-Pep #20, optimized to disrupt the AKAP function of PI3Kg.DRI-Pep #20 mimics the native interaction between the N-terminal domain of PI3Kg and PKA, demonstrating nanomolar affinity for PKA, high resistance to protease degradation and high permeability to the pulmonary mucus barrier.DRI-Pep #20 triggers cAMP elevation both in vivo in the airway tract of mice upon intratracheal administration, and in vitro in bronchial epithelial cells of CF patients.In CF cells, DRI-Pep #20 rescues the defective function of the cAMP-operated channel cystic fibrosis conductance regulator (CFTR), by boosting the efficacy of approved CFTR modulators.These results position DRI-Pep #20 as a potent PI3Kg/PKA disruptor for achieving therapeutic cAMP elevation in respiratory disorders.Overall, these data point to the use of PI3Kγ/PKA peptide disruptors as effective tools to manipulate the cAMP/PKA signaling in a compartmentalized manner, paving the way for targeted therapies with fewer side effects and improved efficacy in the realm of respiratory obstructive disease.
Author: DELLA SALA, ANGELA
Language: English
Subfield: Pulmonary and Respiratory Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: green
Funders: Compagnia di San Paolo, Cystic Fibrosis Canada, Bundesministerium für Bildung und Forschung, Fondazione Cariplo, Ministero della Salute, Università degli Studi di Torino, Fondazione per la Ricerca sulla Fibrosi Cistica, Regione Lombardia, National Institutes of Health, Canadian Institutes of Health Research, Fonds de Recherche du Québec - Santé
OpenAlex ID: W7218292140