Egr1 promotes Nlrc4-dependent neuronal pyroptosis through phlda1 in an in-vitro model of intracerebral hemorrhage

Abstract

Intracerebral hemorrhage (ICH) is a fatal brain injury, but the current treatments for it are inadequate to reduce the severity of secondary brain injury. Our study aims to explore the molecular mechanism of Egr1 and Phlda1 in regulating hemin-induced neuronal pyroptosis, and hope to provide novel therapeutic targets for ICH treatment. Mouse hippocampal neuron cells treated with hemin were used to simulate an in-vitro ICH model. Using qRT-PCR and western blot to evaluate mRNA and protein concentrations. MTT assay was utilized to assess cell viability. LDH levels were determined by lactate Dehydrogenase Activity Assay Kit. IL-1β and IL-18 levels were examined by ELISA. The interaction of Egr1 and Phlda1 promoter was evaluated using chromatin immunoprecipitation and dual-luciferase reporter assays. Egr1 and Phlda1 were both upregulated in HT22 cells following hemin treatment. Hemin treatment caused a significant reduction in HT22 cell viability, an increase in Nlrc4 and HT22 cell pyroptosis, and heightened inflammation. However, knocking down Egr1 neutralized hemin-induced effects on HT22 cells. Egr1 bound to the promoter of Phlda1 and transcriptionally activated Phlda1. Silencing Phlda1 significantly reduced Nlrc4-dependent neuronal pyroptosis. Conversely, overexpressing Phlda1 mitigated the inhibitory effects of Egr1 knockdown on Nlrc4 and neuronal pyroptosis during ICH. Egr1 enhanced neuronal pyroptosis mediated by Nlrc4 under ICH via transcriptionally activating Phlda1.