GDF15 regulated by HDAC2 exerts suppressive effects on oxygen–glucose deprivation/reoxygenation-induced neuronal cell pyroptosis via the NLRP3 inflammasome

Abstract

Abstract Background Pyroptosis, inflammation-related programed cell death mediated by NLRP3 inflammasome, is involved in the pathogenesis of cerebral hypoxic–ischemic injury. Our study aims to explore the biological role of growth differentiation factor (GDF)15 in oxygen–glucose deprivation/reoxygenation (OGD/R)-induced neuronal pyroptosis. Methods HT22 neurons were subjected to OGD/R to simulate cerebral hypoxic–ischemic injury. Cells were transfected with plasmids to overexpress GDF15, or lentiviral-based shRNAs constructs to silence GDF15. ELISA assay was used to detect GDF15, IL-1β, IL-18, and neuron specific enolase (NSE) levels. Cell pyroptosis was measured by flow cytometery. Chromatin immunoprecipitation assay was used to detect interaction of H3K27ac with GDF15 promoter. GDF15, NLRP3, Caspase-1 p20 and GSDMD-N expressions were measured by Western blotting. Results Patients with malignant middle cerebral artery infarction showed decreased GDF15, but increased IL-1β, IL-18, and NSE levels in serum compared to healthy controls. OGD/R treatment caused significant increases in the levels of IL-1β, IL-18 and NSE, percentages of pyroptotic cells, and expressions of NLRP3, Caspase-1 p20, and GSDMD in HT22 cells, which were markedly reversed by GDF15 overexpression. However, GDF15 knockdown resulted in neuronal injury similar to those observed in OGD/R treatment. The GDF15 knockdown-induced effects were counteracted by treatment with NLRP3 inhibitor. OGD/R decreased the enrichment of H3K27ac in the promoter of GDF15 to down-regulate GDF15, but was compromised by co-treatment with HDAC2 inhibitor. Conclusion Our data demonstrates that GDF15 attenuates OGD/R-induced pyroptosis through NLRP3 inflammasome. HDAC2 is involved in mediating OGD-induced GDF15 down-regulation via H3K27ac modification. GDF15 overexpression and HDAC2 inhibition hold potential as useful therapeutic strategies for neuroprotection.