P2X7 Receptor Orchestrates Multiple Signalling Pathways Triggering Inflammation, Autophagy and Metabolic/Trophic Responses.

P2X7 receptor is an ion channel activated by extracellular adenosine trisphosphate (eATP) that attracted increasing attention for its role in immune reactions, neurobiology and oncology. As receptor for an extracellular ligand, P2X7 activates a series of intracellular signalling pathways mainly via alterations of the ion permeability, but also through formation of a large unselective pore and direct interaction with other proteins. Here we wish to give an overview on the main biochemical paths initiated by P2X7 activation by revising recent and established literature on P2X7-triggered signalling cascades leading to cell death, inflammatory and immune response activation, proliferation and metabolism modulation. We will focus on the well-known P2X7 inflammasome/NF-kB and pro-apoptotic networks but also cover P2X7-activated emerging autophagic, pyroptotic and proliferativeoncogenic pathways, like beclin-1/LC3-II, caspase-11, Akt and VEGF axes.