Exploring airway smooth muscle-mediated mast cell function at the single cell level using carbon-fiber microelectrode amperometry

Abstract An important distinguishing feature of asthma pathology is the migration of mast cells (MCs) into the airway smooth muscle (ASM). MCs are known to influence the immune response in a variety of capacities, including the release of many stored immunoactive mediators from secretory vesicles via exocytosis. Conversely, ASM is known to produce several mediators that potentially influence MC activity including the chemoattractant CXCL10. However, the specific consequences of interaction between MCs and ASM on asthma pathophysiology have yet to be fully explored. Carbon-fiber microelectrode amperometry (CFMA) is a unique analytical tool that allows the direct and label free detection of secreted serotonin as it is released from a single MC. Individual packets of serotonin corresponding to single vesicle fusion events are manifested as discrete current spikes in the collected amperometric trace. Individual spike analysis of each trace provides information such as vesicular content and delivery capacity, vesicle fusion efficiency and other kinetic information pertaining to exocytosis regulation. To explore the relationship between MCs and ASM in asthma, CFMA was used to monitor the effects of ASM and asthma-related factors, such as the cytokines CXCL10 and RANTES, on MC function in vitro. Analysis of CFMA data has shown significant modulation of MC secretory function in response to these factors, demonstrating the value of CFMA for the study of MC-related inflammatory processes.