Acetylcholine beyond bronchoconstriction: roles in inflammation and remodeling

Area of Science:

• Pulmonary Medicine
• Neuroscience
• Pharmacology

Background:

• Acetylcholine is a key neurotransmitter in the airways, regulating vital functions.
• It mediates bronchoconstriction, mucus secretion, inflammation, and airway remodeling.
• The muscarinic M3 receptor is implicated in these acetylcholine-driven processes.

Purpose of the Study:

• To review the role of acetylcholine and the muscarinic M3 receptor in airway physiology and pathology.
• To propose that M3 receptor-mediated pathways are central to acetylcholine's effects on airways.
• To explore the therapeutic implications of targeting M3 receptors in obstructive lung diseases.

Main Methods:

• Literature review focusing on acetylcholine, muscarinic receptors, and airway diseases.
• Analysis of studies investigating the mechanisms of acetylcholine's action in the airways.
• Synthesis of evidence linking M3 receptor activity to inflammation and remodeling.

Main Results:

• Acetylcholine induces bronchoconstriction and mucus secretion, primarily through the M3 receptor.
• It also promotes airway inflammation and remodeling via direct cellular effects and mechanical stress.
• Both neuronal and non-neuronal acetylcholine contribute to these inflammatory and remodeling processes.
• Evidence suggests M3 receptor mediation for all discussed effects.

Conclusions:

• The muscarinic M3 receptor is a central mediator of acetylcholine's diverse effects in the airways.
• Anticholinergic therapies targeting M3 receptors may offer benefits for patients with COPD and asthma.
• These benefits likely stem from simultaneous modulation of bronchoconstriction, mucus secretion, inflammation, and remodeling.