P2X7 receptor inhibition ameliorates ubiquitin–proteasome system dysfunction associated with Alzheimer’s disease
Background: Over recent years, increasing evidence suggests a causal relationship between neurofibrillary tangles (NFTs) formation, the main histopathological hallmark of tauopathies, including Alzheimer's disease (AD), and the ubiquitin-proteasome system (UPS) dysfunction detected in these patients. Nevertheless, the mechanisms underlying UPS failure and the factors involved remain poorly understood. Given that AD and tauopathies are associated with chronic neuroinflammation, here, we explore if ATP, one of the danger-associated molecules patterns (DAMPs) associated with neuroinflammation, impacts on AD-associated UPS dysfunction.
Methods: To evaluate if ATP may modulate the UPS via its selective P2X7 receptor, we combined in vitro and in vivo approaches using both pharmacological and genetic tools. We analyze postmortem samples from human AD patients and P301S mice, a mouse model that mimics pathology observed in AD patients, and those from the new transgenic mouse lines generated, such as P301S mice expressing the UPS reporter UbG76V-YFP or P301S deficient of P2X7R.
Results: We describe for the first time that extracellular ATP-induced activation of the purinergic P2X7 receptor (P2X7R) downregulates the transcription of β5 and β1 proteasomal catalytic subunits via the PI3K/Akt/GSK3/Nfr2 pathway, leading to their deficient assembly into the 20S core proteasomal complex, resulting in a reduced proteasomal chymotrypsin-like and postglutamyl-like activities. Using UPS-reported mice (UbGFP mice), we identified neurons and microglial cells as the most sensitive cell linages to a P2X7R-mediated UPS regulation. In vivo pharmacological or genetic P2X7R blockade reverted the proteasomal impairment developed by P301S mice, which mimics that were detected in AD patients. Finally, the generation of P301S;UbGFP mice allowed us to identify those hippocampal cells more sensitive to UPS impairment and demonstrate that the pharmacological or genetic blockade of P2X7R promotes their survival.
Conclusions: Our work demonstrates the sustained and aberrant activation of P2X7R caused by Tau-induced neuroinflammation contributes to the UPS dysfunction and subsequent neuronal death associated with AD, especially in the hippocampus.
Spanish Ministry of Economy and Competitiveness RTI2018-095753-B-I00 and PID2021-125364OB-I00
European Union project H2020-MSCA-ITN-2017 number 766 124
DFG, Project-ID: 335447717—SFB 1328
UCM-Santander Central Hispano Bank PR41/17–21014
UCM postdoctoral researcher (CT48/19)
H2020-MSCA-ITN-2017 (grant number 766124)
Spanish Ministry of Science and innovation (Ramon y Cajal- RYC2018-024435-I and PID2020-113270RA-I00)
Autonomous Community of Madrid (Atracción de Talento-2019T1/BMD-14057
CommentsThe original article is available at https://alzres.biomedcentral.com/
Published CitationBianchi C, et al. P2X7 receptor inhibition ameliorates ubiquitin-proteasome system dysfunction associated with Alzheimer's disease. Alzheimers Res Ther. 2023;15(1):105.
Publication Date7 June 2023
- Physiology and Medical Physics
- FutureNeuro Centre
- Published Version (Version of Record)