Rhinovirus C15 Induces Airway Hyperresponsiveness via Calcium Mobilization in Airway Smooth Muscle

Area of Science:

• Immunology
• Respiratory Medicine
• Virology

Background:

• Rhinovirus (RV) infections are a major trigger for asthma exacerbations, significantly impacting global health.
• The precise mechanisms by which RV induces airway hyperresponsiveness (AHR) and how different RV serotypes contribute to AHR remain poorly understood.
• Understanding RV's role in asthma pathogenesis is crucial for developing targeted therapies.

Purpose of the Study:

• To investigate the mechanisms by which RV infection induces AHR and inflammatory mediator release.
• To determine if rhinovirus C-induced AHR involves mediator release from epithelial cells affecting human airway smooth muscle.
• To correlate viral load with AHR and inflammatory responses in an ex vivo human lung model.

Main Methods:

• Utilized an ex vivo model using human precision cut lung slices (hPCLS) to assess bronchoconstriction and mediator release following RV infection.
• Measured carbachol-induced airway narrowing and the release of specific inflammatory mediators (IP-10, MIP-1β, IL-6) after RV-C15 infection.
• Investigated the effects of RV-C15 infection on agonist-induced intracellular calcium flux and myosin light chain phosphorylation in co-cultured human airway smooth muscle and epithelial cells.

Main Results:

• Rhinovirus C15 (RV-C15) infection significantly augmented carbachol-induced airway narrowing in hPCLS.
• RV-C15 infection led to increased release of IP-10 and MIP-1β, but not IL-6.
• RV-C15 infection of airway epithelial cells enhanced carbachol-induced calcium flux and myosin light chain phosphorylation in co-cultured airway smooth muscle, an effect not observed with histamine stimulation.

Conclusions:

• RV-C15-induced inflammatory responses in structural cells are associated with viral load.
• The inflammatory responses and altered agonist-mediated constriction in human small airways following RV-C15 infection appear uncoupled from the overall tissue viral load.
• Epithelial mediator release plays a role in RV-C15-induced airway hyperresponsiveness by modulating calcium signaling in airway smooth muscle.