New role of P2X7 receptor in an Alzheimer's disease mouse model

Extracellular aggregates of amyloid beta (A beta) peptides, which are characteristic of Alzheimer's disease (AD), act as an essential trigger for glial cell activation and the release of ATP, leading to the stimulation of purinergic receptors, especially the P2X7 receptor (P2X7R). However, the involvement of P2X7R in the development of AD is still ill-defined regarding the dual properties of this receptor. Particularly, P2X7R activates the NLRP3 inflammasome leading to the release of the pro-inflammatory cytokine, IL-1 beta; however, P2X7R also induces cleavage of the amyloid precursor protein generating A beta peptides or the neuroprotective fragment sAPP alpha. We thus explored in detail the functions of P2X7R in AD transgenic mice. Here, we show that P2X7R deficiency reduced A beta lesions, rescued cognitive deficits and improved synaptic plasticity in AD mice. However, the lack of P2X7R did not significantly affect the release of IL-1 beta or the levels of non-amyloidogenic fragment, sAPP alpha, in AD mice. Instead, our results show that P2X7R plays a critical role in A beta peptide-mediated release of chemokines, particularly CCL3, which is associated with pathogenic CD8(+) T cell recruitment. In conclusion, our study highlights a novel detrimental function of P2X7R in chemokine release and supports the notion that P2X7R may be a promising therapeutic target for AD.