TRPM3, P2X2 and P2X3 expression patterns in single airway sensory nerves

We examined the distribution of TRPM3, P2X2&P2X3 in single airway neurons.Airway terminating neurons isolated from GPs were individually harvested & single-cell gene expression evaluated.P2X3 was expressed in 23/32 Jugular (J) & 22/37 Nodose (N) neurons, P2X2 was expressed in 1/32 J & 16/37 N, & P2X2 was co-expressed in 15/47 P2X3 neurons. Most A-fibres originate from the N ganglion, where P2X2/3 co-expression was predominant, and most C-fibres originate from the J ganglion where P2X3 was predominant. TRPM3 was expressed on 22/32 J and 14/37 N neurons, and co-expressed in 34/49 P2X expressing neurons.These results suggest P2X2/3 expression is A-fibre predominant, and required for firing caused by endogenous ATP release. This may explain why TRPV4, which we found to only activate nodose neurons, only fires A-fibres. The frequent expression of TRPM3 on J neurons explains P2X2/3-independent firing of C-fibres by TRPM3. This work shows how single cell expression can determine ion channel profiles of different nerve populations, which may aid drug targeting and differentiation for patients with altered sensory reflex responses and enhanced cough in chronic lung diseases.
Source: European Respiratory Journal - Category: Respiratory Medicine Authors: Tags: Airway Pharmacology and Treatment Source Type: research