Novel Insights into Macrophage Regulation by P2X7R Mediated Pathways

Abstract

The P2X7 receptor (P2X7R) is an ion channel gated by extracellular ATP and is primarily found in immune cells. P2X7R is involved in the regulation of inflammation and the immune response. Although P2X7R has been suggested as a potential therapeutic target due to its involvement in the assembly and activation of the NLRP3 inflammasome, it has also been described that ATP-mediated activation of P2X7R can lead to the activation of other cellular pathways. However, our understanding of the biological processes downstream of P2X7R activation is still far from complete. This thesis aims to describe different pathways that may be controlled by the activation of P2X7R and investigate how they interact with each other. Firstly, this research describes the cross-talk between the NLRP3 inflammasome and type I interferon (IFN), which has also been reported to be influenced by the activation of P2X7R. Here, we describe that in patients with type I interferonopathies and in vitro assays, genes related to the NLRP3 inflammasome were upregulated. However, we observed that this transcriptional regulation mediated by type I IFN does not regulate the activation of the NLRP3 inflammasome. Moreover, through phosphoproteomic studies, we observed that the activation of P2X7R leads to changes in the phosphorylation status of various proteins related to the production and signalling of Type I IFN. However, in our studies, we did not observe a regulation in the activity of Type I IFN mediated by the activation of P2X7R. Finally, in this thesis, we explore the relationship between P2X7R and pyruvate dehydrogenase E1 subunit alpha 1 (PDHE1a). The activation of P2X7R leads to the activation of PDHE1a through the dephosphorylation of its residues S293, S300, and S232, mediated by a calcium-dependent mechanism. Thus, this thesis made a novel contribution to the understanding of the pathways controlled by P2X7R and how they interact in the context of P2X7R activation.

Date of Award	16 Feb 2024
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Paul Kasher (Co Supervisor), Gloria Lopez-Castejon (Main Supervisor), Tracy Briggs (Co Supervisor) & John Grainger (Co Supervisor)