G Protein-Coupled Receptor 30 Attenuates Neuronal Pyroptosis Induced by Subarachnoid Hemorrhage

Background: Pyroptosis is implicated as a pathogenic mechanism in early brain injury (EBI) after subarachnoid hemorrhage (SAH). This study aimed to investigate the regulatory role of G protein-coupled receptor 30 (GPR30) in neuronal pyroptosis during SAH. Methods: SAH was induced in rats via intravascular perforation and hemin-treated neurons modeled SAH in vitro. GPR30 agonist G1 and antagonist G15 were administered to assess functional impacts. Neurological deficits (Garcia score), SAH severity, and cerebral edema (brain water content) were evaluated. Pyroptotic markers (cleaved caspase-1, gasdermin D (GSDMD)-N, interleukin (IL)-1β, and IL-18) were quantified. Inflammasome activation (NLRC4 and IFI16) and Toll-like receptor 4/nuclear factor kappa-B (TLR4/NF-κB) signaling were analyzed via immunofluorescence (IF) and immunoblotting. The TLR4 antagonist LPS-RS (lipopolysaccharide from Rhodobacter sphaeroides) was applied to validate pathway involvement. Results: GPR30 expression increased post-SAH. G15 exacerbated hemorrhage severity, neurological deficits, and cerebral edema, whereas G1 modestly attenuated SAH. G15 upregulated pyroptotic markers, enhanced neuronal pyroptosis, and activated NLRC4/IFI16 inflammasomes. Concurrently, G15 stimulated TLR4/MyD88 expression and NF-κB phosphorylation. Conversely, G1 suppressed pyroptosis, inactivated inflammasomes, and inhibited TLR4/NF-κB signaling. LPS-RS cotreatment reversed G15-induced pyroptotic and inflammatory cascades. Conclusion: GPR30 mitigates NLRC4- and IFI16-driven neuronal pyroptosis in SAH by modulating TLR4/NF-κB signaling. Pharmacological targeting of GPR30 represents a promising therapeutic strategy to ameliorate SAH-associated brain injury.