Endocytic Trafficking of G-Protein-Coupled Receptors as a Novel Regulator of Inflammation

This project will investigate and develop the basic understanding of the processes required to bring about the resolution of inflammation based on our recent novel advances in the understanding of receptor pharmacology. Inflammation is a natural process that helps restore tissue homeostasis after injury or infection. However, when inflammation becomes uncontrolled it can be hazardous to health. For example, sepsis is when the body's normal inflammatory response is so severe that it fails to resolve and causes injury to the body's organs. This is the most common cause of death within intensive care, accounting for ~35,000 deaths in the UK each year. Understanding the molecular mechanisms of how inflammation is regulated and resolved naturally in health and in specific disorders is therefore critical to well-being and for the development of more effective therapies [1].

One critical regulator of inflammation is the family of G-protein-coupled receptors; the formyl peptide receptors (FPR), and in particular, FPR2, thought to be responsible for resolution. These receptors modulate a variety of responses, from leukocyte activation and migration, to apoptosis and phagocytosis. However, the molecular mechanisms underlying exactly how GPCRs are involved in these processes and thus, their therapeutic potential in the treatment of sepsis remains unclear. Excitingly, our recent work has uncovered new insight [2], indicating that endocytic trafficking of FPR2 plays a critical role in resolution of inflammation. Endocytic trafficking controls the number of functional receptors available, allowing the cell to increase or decrease signalling amplitude in response external stimuli [3]. We have discovered that disruption of FPR2 trafficking leads to increased cellular apoptosis; a key requirement for resolution. This finding provides a novel molecular target for understanding of inflammation and the development of therapeutics. Building on these findings, the project will consist of 3 parts:

1) Investigate the molecular pharmacology and endocytic trafficking of FPRs
2) Develop peptide inhibitors of endocytic trafficking
3) Analyse the functional consequences of altered FPR2 function by the use of gene editing to generate a novel mouse model to show effects in vivo

This studentship will employ and provide training in a diverse array of modern scientific techniques, specifically we will use cutting edge imaging techniques (super-resolution, real-time confocal microscopy, fluorescent biosensors) to investigate and identify the mechanism by which the formyl peptide receptor undergoes endocytic trafficking and how this regulates signalling, cytokine production, migration and phagocytosis to determine the strength of the inflammatory response. We will develop peptide inhibitors based on the amino acid sequence of the formyl peptide receptor, which will be synthesized in house, and used to perturb trafficking. Finally new gene editing techniques will be used to generate a mouse line expressing trafficking impaired receptors to validate, in vivo, the importance of this process in animal models of inflammation. This interdisciplinary and collaborative project addresses the BBSRC strategy of world-class underpinning bioscience by promising to identify fundamental mechanisms regulating inflammation and validate new targets and potentially identify new small molecule inhibitors for the future development for the treatment of inflammation.

1) Ortega-Gómez A, Perretti M, Soehnlein O. EMBO Mol Med. 2013 May;5(5):661-74.
2) Thompson D, McArthur S, Hislop JN, Flower RJ, Perretti M (2014) J Biol Chem. 26;289(52):36166-78.
3) Hislop JN, von Zastrow M. Traffic. 2011;12:137-48.