Mast cells are strongly implicated in the pathogenesis of asthma. However, the role of different mast cell populations and mediators in the pathology of asthma remain unclear. We hypothesize that there is a phenotypical and functional heterogeneity among human lung mast cells that play a pivotal role for the features of asthma and we aim to characterize the heterogeneity in unbiased ways. We use mast cells obtained from human lung tissue removed during surgery primarily due to cancer. To investigate the RNA profile of lung mast cells we will perform RNA sequencing of sorted mast cell populations and single cell RNA sequencing to determine if we on the RNA level can identify and group the mast cells into distinct populations. On the protein level we have used a flow cytometry panel of 334 different markers and have preliminary results showing novel and interesting markers with a high degree of expression variability within the mast cell population. Combining the information, from our two unbiased approaches, legendscreen and single cell RNA sequencing, we hope to identify possible heterogeneity marker for the human lung mast cells. Co-staining of the identified markers will be analyzed by flow cytometry to define novel mast cell subpopulations that will be isolated and investigated for their differences in functionality and sensitivity to pharmacological interventions.
We have identified the expression of Frizzled-receptors on the mast cells. The agonists to the Frizzled receptors are Wnts and recent findings have implicated Wnt pathways in critically regulating inflammatory responses, especially in asthma. The role(s) of Wnt signaling in mast cells is however unknown and to investigate this we will investigate the in vitro response of human mast cells to different Wnts and examine receptor activation, proliferation, differentiation, reactivity and release of mediators.
This project has the potential to discover functionally different novel mast cell subpopulations, as well as novel roles for Wnt signaling in mast cells that can have an impact on diseases were mast cells play a central role in the lung, such as asthma.