Investigating a role for activity-regulated cytoskeleton-associated protein in the mast cell response to external stimuli, including hydrogen peroxide

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In the first year of the Integrated PhD, Anna Willis will attend an induction and introductory training programme followed by taught modules in Research Skills for Biomedical Sciences, Quantitative Cell Biology anEnvironmental factors such as pathogens, allergens, or pollution have been shown to induce asthma exacerbations and contribute to the development of respiratory disease. Mast cells (MCs) are localised at mucosal surfaces where they are part of the first line of defence against environmental challenges. There are increased numbers of MCs with an activated phenotype in the lungs of asthma patients, which release proinflammatory mediators in response to these stimuli. MC mediators can induce chronic inflammation, airway hyperresponsiveness and broncho-constriction in those with pre-existing inflammation, therefore MCs have been implicated in asthma pathogenesis. Hydrogen peroxide (H2O2) generated by exposure to pollutants can contribute to asthma pathogenesis through promotion of airway remodelling and the induction of leukocyte recruitment and cytokine expression. Similarly, Rhinovirus (RV) infection is a major cause of asthma exacerbations through its induction of an immune response which involves release of proinflammatory cytokines and chemokines, and recruitment of immune cells which exacerbate inflammation. A transcriptomic analysis identified activity-regulated cytoskeleton-associated protein (ARC) as the most highly upregulated gene in RV16-infected LAD2 MCs. ARC regulates cytoskeleton rearrangement, with a well-defined role in neuroplasticity and forming synaptic connections. There is limited research on the function of ARC outside of its role in synaptic transmission. However, recent studies show a role for ARC in the response to heat shock and H2O2 in epithelial cells, as well as in the replication and release of herpes simplex virus 1 (HSV-1) replication from neurons. This project investigates a role for ARC in the MC response to H2O2 and RV16 infection. I have shown an induction of ARC gene and protein expression in response to H2O2 treatment in HeLa cells and MCs, as well as induction of HSPA1A, HSPA1B and HSPB1 gene expression in response to H2O2 in LAD2 MCs. I also carried out a transcriptomic analysis which shows that CACNG3 and ARC are the most highly upregulated genes in RV16-infected LAD2 MCs. Knock down of ARC in LAD2 MCs using siRNA transfection required further optimisation before it can be used to investigate a role for ARC in the MC response to H2O2 and RV infection.