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Published on: January 22, 2016
Adenosine A2A Receptor Contributes to Bidirectional Remodeling of Microglial Inflammatory Responses During
Zhenping Hou1, Xinjie Zhang1, Genmeng Yang1
1National Health Commission (NHC) Key Laboratory of Drug Addiction Medicine, School of Forensic Medicine, Kunming Medical University, 1168 West Chunrong Road, Yuhua Avenue, Chenggong District, Kunming 650500, China.
Abstract:
To investigate the role of the adenosine A2A receptor (A2AR) in methamphetamine (MA)-induced microglia-mediated neuroinflammation and to explore the potential signaling mechanism, postmortem human striatal tissue from MA users, a male C57BL/6 mouse model of MA exposure, and the human microglial cell line HMC3 were examined by Western blotting, immunofluorescence, and related assays. Across all three experimental systems, MA exposure significantly upregulated A2AR expression together with alterations in downstream PKA and PKC signaling. These signaling changes were accompanied by parallel upregulation of pro-inflammatory mediators (iNOS, IL-1β, and IL-18) and of anti-inflammatory and repair-associated factors (Arg-1 and IL-10), suggesting that MA did not trigger a simple unidirectional inflammatory program but instead induced multidimensional phenotypic remodeling of microglia that varied with exposure time and dose. Intervention with the selective A2AR antagonist SCH58261 showed that pharmacological inhibition of A2AR markedly attenuated MA-induced alterations in PKA/PKC signaling and suppressed the accompanying shifts in inflammatory mediator expression, thereby mitigating the neuroinflammatory response. These results suggest that A2AR is involved in the modulation of MA-induced microglial inflammatory responses and may contribute to the mixed inflammatory state characterized by simultaneous changes in pro-inflammatory and anti-inflammatory markers, possibly associated with PKA/PKC signaling. This study expands current understanding of the inflammatory basis of MA-related neurotoxicity and suggests A2AR as a potential target for therapeutic intervention in MA abuse.
Insights
Methamphetamine (MA) triggers neuroinflammation by altering adenosine A2A receptor (A2AR) expression and signaling in microglia. Blocking A2AR reduces MA-induced inflammation, suggesting it as a therapeutic target for MA abuse.
Area of Science:
- Neuroscience
- Pharmacology
- Immunology
Background:
- Methamphetamine (MA) abuse is linked to neurotoxicity and neuroinflammation.
- Microglia play a critical role in mediating neuroinflammation.
- The adenosine A2A receptor (A2AR) is implicated in various neurological processes.
Purpose of the Study:
- To investigate the role of A2AR in MA-induced microglia-mediated neuroinflammation.
- To explore the signaling mechanisms underlying MA-induced neuroinflammation.
- To evaluate A2AR as a potential therapeutic target for MA abuse.
Main Methods:
- Western blotting and immunofluorescence on human striatal tissue, mouse models, and HMC3 cells.
- Analysis of A2AR expression and downstream signaling pathways (PKA, PKC).
- Assessment of pro-inflammatory (iNOS, IL-1β, IL-18) and anti-inflammatory (Arg-1, IL-10) mediators.
- Pharmacological intervention using the A2AR antagonist SCH58261.
Main Results:
- MA exposure upregulated A2AR expression and altered PKA/PKC signaling in microglia.
- MA induced a mixed inflammatory response with simultaneous changes in pro- and anti-inflammatory mediators.
- Inhibition of A2AR with SCH58261 attenuated MA-induced signaling alterations and inflammatory mediator shifts.
- A2AR antagonism mitigated the overall neuroinflammatory response.
Conclusions:
- A2AR is involved in modulating MA-induced microglial inflammatory responses.
- A2AR contributes to the mixed inflammatory state observed in MA neurotoxicity, potentially via PKA/PKC signaling.
- A2AR represents a potential therapeutic target for intervention in MA abuse and related neuroinflammation.
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