Using super-resolution microscopy to study immune cell biology in asthma and chronic obstructive pulmonary disease

Lead Research Organisation: University of Manchester
Department Name: School of Biological Sciences

Abstract

The key focus of my research over recent years has been in addressing important problems in cell biology and immunology with novel and state-of-the-art photonics technology combined with molecular and cell biology techniques. Our imaging studies have helped establish an emerging new paradigm that interactions between immune cell receptors, kinases and adaptors are at least in part controlled by the dynamics of supramolecular assemblies at an intercellular contact or immune synapse. Thus, immune cell recognition and signalling is governed by transient interactions between heterogeneous clusters of proteins, a substantially different concept from the linear cascade of individual protein-protein interactions depicted in textbooks. From these data, emerges a new hypothesis; that the nanoscale organisation of immune cell surfaces varies in health and disease which this significantly impacts immunity. This idea has the potential to seed an entirely novel route to drug design; manipulating the organisation of the immune cell surface to augment or dampen immune cell responses.
A considerable body of preliminary data underpins this specific proposal. It has been assumed that activating Fc receptors and the inhibitory receptor signal regulatory protein alpha (SIRPalpha) are evenly distributed at the macrophage cell surface and cluster upon ligation or cross-linking. However, we have recently found that these proteins are not homogeneously distributed at the cell surface but are organized in nanometre-scale clusters at the surface of primary human macrophages (manuscript pending revisions). In resting cells, nanoclusters of activating and inhibitory receptors are co-localized, constrained by the actin cytoskeleton. Ligation of Fc receptor, and subsequent signaling via Src-family kinases, induces the segregation of activating and inhibitory nanoclusters, establishing a positive feedback for cellular activation, by segregating phosphatase and kinase activity; a process blocked by co-ligation of inhibitory receptors.
We now aim to build upon these findings to explore how the changing arrangement of cell surface proteins impacts disease. Using alveolar macrophages taken from healthy donors or patients, we will compare, for example, the extent to which SIRPalpha inhibits Fc receptor signaling in comparison to its proximity to the activating Fc receptors which mediate phagocytosis, as well as signalling events from these activating receptors. This will reveal how an altered organisation of macrophage surfaces could impact impaired pathogen recognition or resolution of inflammation in the lung. We will use patterned surfaces to further test the importance of the proximity of activating and inhibitory signals in signal integration. These data will establish how changes in the cell surface organisation impacts disease states in lung inflammation.

Publications

10 25 50
 
Description Phenotyping NK cells using flow cytometry 
Organisation University of Cambridge
Country United Kingdom 
Sector Academic/University 
PI Contribution We established the collaboration at the recent UK NK cell conference in London. Andrew Sharkey presented data on decidual NK cell phenotype, and we asked whether we could provide our own samples for him to analyse using the same methods. This will hopefully take place in the near future.
Collaborator Contribution The collaborators will analyse samples of NK cells co-incubated with beads of different stiffness provided by me, determining their phenotype and cytokine profile using flow cytometry.
Impact The collaboration is in the early stages so there are no outcomes yet.
Start Year 2020
 
Description Biological Sciences Interview Preparation with the Karta Initiative, India 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Schools
Results and Impact Over 8 weeks I held discussions with 2 students from rural Indian schools who were preparing for interviews with UK universities. I discussed my work and asked questions to improve their understanding.
Year(s) Of Engagement Activity 2019