Dysregulation of exosomal miRNAs in A2 astrocytes under oxygen-glucose deprivation is associated with neuronal pyroptosis: a role for miR-139-5p in targeting NLRP3.

Abstract

A2 astrocyte exosomes are closely associated with neuronal pyroptosis. Reduced expression of miR-139-5p was detected in A2 astrocyte exosomes under oxygen-glucose deprivation (OGD) conditions. We postulate that miR-139-5p intensifies neuroinflammation by modulating the expression of neuronal NLRP3 pyroptosis protein. To identify differentially expressed exosomal miRNAs from A2 astrocytes under OGD conditions and to evaluate their potential roles in neuronal pyroptosis. Administer interleukin-4 (IL-4) to microglia, harvest the supernatant to induce A2 astrocytes, expose them to oxygen deprivation models to isolate exosomes, then co-culture these exosomes with both healthy neurons and neurons subjected to OGD conditions to assess pyroptosis levels in the neurons. Subsequently, execute miRNA sequencing on exosomes from various circumstances to analyze differentially expressed microRNAs and their associated pathways. Finally, the differential targeting relationship between miR-139-5p and NLRP3 was validated using a dual luciferase reporter assay. Oxygen-glucose deprivation (OGD) reduced A2 astrocyte viability, with 1 h selected as the optimal duration (p < 0.001). Exosomes from OGD-treated astrocytes were internalized by neurons, decreasing viability (p < 0.001) and increasing pyroptosis-related proteins (p < 0.01). miRNA sequencing identified 133 differentially expressed miRNAs (62 upregulated, 71 downregulated), with miR-139-5p significantly downregulated. Dual-luciferase assays confirmed that miR-139-5p directly targets NLRP3 (p < 0.001). Of five pyroptosis-associated exosomal miRNAs (miR-214-3p, miR-22-5p, miR-139-5p, miR-382-3p, and miR-365-5p), miR-139-5p and miR-382-3p were downregulated under OGD, and miR-139-5p directly targeted NLRP3. Thus, exosomal miRNAs, particularly miR-139-5p, warrant further therapeutic investigation in neurodegenerative diseases, including degenerative cervical myelopathy.