IADR Abstract Archives
Investigating the role of acetylcholine in the pathogenesis of candidiasis
Objectives: The majority of cells synthesise acetylcholine (ACh) and cholinergic pathways have previously been demonstrated to modulate host immune responses. However, the role of ACh in the pathogenesis of candidiasis remains unknown. The aim of this study was to determine if ACh modulates Candidia albicans growth and biofilm formation, and also the effect(s) of ACh on the host immune response using a Galleria mellonella candidiasis infection model.
Methods: ACh levels were measured in the saliva of denture wearers, with and without denture stomatitis (DS), using a choline/acetylcholine assay kit (Abcam, UK). G. mellonella larvae were infected with C. albicans with and without ACh and Kaplan-Meier survival kinetics were determined. In addition, the effects of ACh on G. mellonella immunity and C. albicans biofilm formation, in vivo, were monitored by qPCR targeting key G. mellonella antimicrobial peptide genes (Galleriomycin, Gallerimycin and Transferrin) and C. albicans genes involved in biofilm formation (HWP1 and ALS3). The effect of ACh on C. albicans metabolic output and biofilm formation was also determined in vitro using phenotype microarray technology (Biolog, USA) and crystal violet assays.
Results: ACh was elevated in the saliva of DS patients and levels correlated significantly with levels of palatial inflammation, as determined by Newton’s score. ACh was found to promote the survival of G. mellonella larvae infected with C. albicans by decreasing fungal burden and the expression of biofilm related genes; HWP1 and ALS3. In addition, G. mellonella antimicrobial peptide expression was also modulated by ACh. In vitro, ACh also inhibited C. albicans metabolic output and biofilm formation.
Conclusions: Preliminary data suggests that ACh plays a role in the pathogenesis of candidiasis by impacting on C. albicans growth and biofilm formation, while also modulating host immune defence systems. This study has implications for the clinical management of mucosal candida infection.
Methods: ACh levels were measured in the saliva of denture wearers, with and without denture stomatitis (DS), using a choline/acetylcholine assay kit (Abcam, UK). G. mellonella larvae were infected with C. albicans with and without ACh and Kaplan-Meier survival kinetics were determined. In addition, the effects of ACh on G. mellonella immunity and C. albicans biofilm formation, in vivo, were monitored by qPCR targeting key G. mellonella antimicrobial peptide genes (Galleriomycin, Gallerimycin and Transferrin) and C. albicans genes involved in biofilm formation (HWP1 and ALS3). The effect of ACh on C. albicans metabolic output and biofilm formation was also determined in vitro using phenotype microarray technology (Biolog, USA) and crystal violet assays.
Results: ACh was elevated in the saliva of DS patients and levels correlated significantly with levels of palatial inflammation, as determined by Newton’s score. ACh was found to promote the survival of G. mellonella larvae infected with C. albicans by decreasing fungal burden and the expression of biofilm related genes; HWP1 and ALS3. In addition, G. mellonella antimicrobial peptide expression was also modulated by ACh. In vitro, ACh also inhibited C. albicans metabolic output and biofilm formation.
Conclusions: Preliminary data suggests that ACh plays a role in the pathogenesis of candidiasis by impacting on C. albicans growth and biofilm formation, while also modulating host immune defence systems. This study has implications for the clinical management of mucosal candida infection.