Abstract
Background
The cholinergic anti-inflammatory pathway (CAP) connects the immune response system and the nervous system via the vagus nerve. The key regulatory receptor is the α7-subtype of the nicotinic acetylcholine receptor (α7nAChR), which is localized on the surface of the cells of immune system. CAP has been proved to be effective in suppressing the inflammation responses in acute lung injury (ALI). Dendritic cells (DCs), the important antigen-presenting cells (APCs), also express the α7nAChR. They not only play an important role in immune response priming but also in participating in the pathological process of ALI. Past studies have indicated that reducing the quantity of mature conventional DCs (cDCs) and inhibiting the maturation of pulmonary DCs may prove effective for the treatment of ALI. However, the effects of CAP on maturation, function and quantity of DCs and cDCs in ALI remain unclear.
Objective
It was hypothesized that the activation of CAP may inhibit the inflammatory response of ALI by regulating maturation, phenotype, and quantity of DCs and cDCs. This can be considered as an important intervention strategy for treating ALI.
Methods
GTS-21 (GTS-21 dihydrochloride), an α7nAchR agonist was administered in sepsis-induced ALI mice model and LPS-primed bone marrow-derived dendritic cells (BMDCs). The effects of GTS-21 were observed with respect to maturation, phenotype, and quantity of DCs, cDCs, and cDCs2 (type 2 cDCs), and the release of DC-related pro-inflammatory cytokines (such as IL-6, TNF-α, IL-18 IL-1β, IL-12p40, and HMGB1) in vivo and in vitro conditions.
Results
The results of the present study revealed that, GTS-21 treatment regulated the maturation of DCs and the production of DC-related pro-inflammatory cytokines in vitro and in sepsis-induced ALI mice model, it reduced the quantity of CD11c+MHCII+ cDCs and CD11c+CD11b+ cDCs2 in vivo experiment.
Conclusions
The activation of CAP contributes to the reduction in the inflammatory response in ALI by regulating maturation, phenotype, and quantity of DCs, cDCs, and cDCs2.