α7-Nicotinic Acetylcholine Receptor Activation Modulates BV2 Microglial Plasticity via miR-21/TNF-α/NFκB in Oxygen–Glucose Deprivation/Reoxygenation

Elevated inflammatory reactions are a significant component in cerebral ischemia–reperfusion injury (CIRI). Activation of α7-Nicotinic Acetylcholine Receptor (α7nAChR) reduces stroke-induced inflammation in rats, but the anti-inflammatory pathway in microglia under CIRI condition remains unclear. This study employed qRT-PCR, protein assays, NanoString analysis, and bioinformatics to examine the effects of PNU282987 treatment (α7nAChR agonist) on BV2 microglial functional differentiation in oxygen–glucose deprivation/reoxygenation (OGDR) condition. OGDR significantly increased the gene expression of pro-inflammatory markers such as TNF-α, IL-6, and IL1β, while α7nAChR agonists reduced these markers. The anti-inflammatory gene marker IL-10 was upregulated by α7nAChR agonist treatment. Downstream pathway marker analysis showed that both gene and protein expression of NFκB was associated with anti-inflammatory effects. Blocking microRNA-21 with antagomir reversed the anti-inflammatory effects. NanoString analysis revealed that microRNA-21 inhibition significantly affected inflammation-related genes, including AL1RAP , TLR9 , FLT1 , PTGIR , NFκB , TREM2 , TNF , SMAD7 , FOS , CCL5 , IFIT1 , CFB , CXCL10 , IFI44 , DDIT3 , IRF7 , OASL1 , IL1A , IFIT2 , C3 , CD40 , STAT2 , IFIT3 , IL1RN , OAS1A , CSF1 , CCL4 , CCL2 , CCL3 , BCL2L1 , and ITGB2 . Enrichment analysis of upregulated genes identified Gene Ontology Biological Processes related to cytokine responses and TNF-associated pathways. This study highlights α7nAChR activation as a key regulator of anti-inflammatory responses in BV2 microglia under OGDR conditions, with micro-RNA21 identified as a crucial mediator of receptor-driven neuroprotection via the TNF-α/NF κ B signalling pathway.