DHX9 aggravates epilepsy by promoting STAT1 phosphorylation to increase oxidative stress and apoptosis

DEAH-box helicase 9 (DHX9), as a member of the RNA helicase family, plays important roles in various diseases, but its specific function and molecular mechanisms in epilepsy remain unclear. This study aims to investigate the role of DHX9 in epilepsy and its interaction mechanisms with STAT1.

Acute and chronic epilepsy mouse models induced by pentylenetetrazole (PTZ) and kainic acid (KA)-induced epilepsy mouse models were established to detect DHX9 expression levels in hippocampal tissue. In vitro epilepsy models were established using HT22 mouse hippocampal neuronal cell lines and BV2 microglial cell lines to analyze DHX9 expression changes. Co-immunoprecipitation was employed to detect protein-protein interactions between DHX9 and STAT1. STAT1-specific inhibitors were used in rescue experiments to validate the critical role of STAT1 in DHX9-mediated pathogenic effects. Western blot and immunofluorescence staining were used to detect oxidative stress markers and apoptosis-related indicators.

DHX9 expression was upregulated in hippocampal tissue from PTZ-induced acute and chronic epilepsy mice and KA-induced epilepsy mice. In vitro experiments confirmed that DHX9 expression was similarly increased in epilepsy models constructed with HT22 neurons and BV2 microglia. Functional studies demonstrated that DHX9 overexpression aggravated neuronal injury, including increased apoptosis rate, elevated oxidative stress levels, and promoted inflammatory responses. Conversely, silencing DHX9 through shRNA reduced neuronal injury in KA-induced epilepsy mouse models. Mechanistic studies revealed that DHX9 silencing exerted neuroprotective effects by inhibiting the STAT1 signaling pathway, reducing oxidative stress and apoptosis. Co-immunoprecipitation experiments confirmed direct protein-protein interactions between DHX9 and STAT1. Rescue experiments further demonstrated that STAT1-specific inhibitors could reverse DHX9 overexpression-induced neuronal injury, proving that STAT1 is a key downstream molecule mediating DHX9's pathogenic effects.

This study reveals the important role of DHX9 in epilepsy pathogenesis and elucidates the molecular mechanism by which DHX9 directly interacts with STAT1 and promotes its phosphorylation, thereby activating downstream oxidative stress and apoptotic signaling pathways, ultimately aggravating epileptic neuronal injury.