P2X4 Receptor Regulates Alcohol-Induced Responses in Microglia
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Mounting evidence indicates that alcohol-induced neuropathology may result from multicellular responses in which microglia cells play a prominent role. Purinergic receptor signaling plays a key role in regulating microglial function and, more importantly, mediates alcohol-induced effects. Our findings demonstrate that alcohol increases expression of P2X4 receptor (P2X4R), which alters the function of microglia, including calcium mobilization, migration and phagocytosis. Our results show a significant up-regulation of P2X4 gene expression as analyzed by real-time qPCR (***p < 0.002) and protein expression as analyzed by flow cytometry (**p < 0.004) in embryonic stem cell-derived microglial cells (ESdM) after 48 hours of alcohol treatment, as compared to untreated controls. Calcium mobilization in ethanol treated ESdM cells was found to be P2X4R dependent using 5-BDBD, a P2X4R selective antagonist. Alcohol decreased migration of microglia towards fractalkine (CX3CL1) by 75 % following 48 h of treatment compared to control (***p < 0.001). CX3CL1-dependent migration was confirmed to be P2X4 receptor-dependent using the antagonist 5-BDBD, which reversed the effects as compared to alcohol alone (***p < 0.001). Similarly, 48 h of alcohol treatment significantly decreased phagocytosis of microglia by 15 % compared to control (*p < 0.05). 5-BDBD pre-treatment prior to alcohol treatment significantly increased microglial phagocytosis (***p < 0.001). Blocking P2X4R signaling with 5-BDBD decreased the level of calcium mobilization compared to ethanol treatment alone. These findings demonstrate that P2X4 receptor may play a role in modulating microglial function in the context of alcohol abuse.
KeywordsMicroglia Alcohol Purinergic receptor X4
The authors would like to acknowledge Nancy L. Reichenbach for editing and Dr. Uma Sriram for critical reading of the manuscript, and Dr. Slava Rom for his expert help with the graphics.
- Asatryan L, Yardley MM, Khoja S, Trudell JR, Hyunh N, Louie SG, Petasis NA, Alkana RL, Davies DL (2014) Avermectins differentially affect ethanol intake and receptor function: implications for developing new therapeutics for alcohol use disorders. Int J Neuropsychopharmacol 1–10Google Scholar
- Davies DL, Asatryan L, Kuo ST, Woodward JJ, King BF, Alkana RL, Xiao C, Ye JH, Sun H, Zhang L, Hu XQ, Hayrapetyan V, Lovinger DM, Machu TK (2006) Effects of ethanol on adenosine 5′-triphosphate-gated purinergic and 5-hydroxytryptamine receptors. Alcohol Clin Exp Res 30:349–358PubMedCrossRefPubMedCentralGoogle Scholar
- Ramirez SH, Fan SS, Dykstra H, Reichenbach N, Del Valle L, Potula R, Phipps RP, Maggirwar SB, Persidsky Y (2010b) Dyad of CD40/CD40 ligand fosters neuroinflammation at the blood–brain barrier and is regulated via JNK signaling: implications for HIV-1 encephalitis. J Neurosci 30:9454–9464PubMedCrossRefPubMedCentralGoogle Scholar