Hydrogen sulfide improves poststroke depression-induced inflammation in microglial cells by enhancing endoplasmic reticulum autophagy and inhibiting the cGAS-STING pathway

Poststroke depression (PSD) affects approximately one-third of stroke survivors, contributing to poor outcomes and elevated mortality. This study aimed to investigate the therapeutic effects of hydrogen sulfide (H 2 S), administered as sodium hydrosulfide (NaHS), on PSD-induced inflammation, with a focus on the modulation of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon gene (STING) pathway and the enhancement of endoplasmic reticulum (ER) autophagy in microglial cells. An in-vivo rat model was established to evaluate the effects of NaHS on depression-like behaviors and inflammation. Mechanistic studies were conducted in vitro using BV2 microglia subjected to oxygen-glucose deprivation (OGD) and corticosterone. Key inflammatory markers, cGAS-STING pathway activity, and ER-autophagy-related proteins were analyzed using quantitative reverse transcription PCR, Western blotting, ELISA, transmission electron microscopy, and immunofluorescence staining. Depression-like behaviors in rats were assessed using the forced swimming and tail suspension tests. H 2 S treatment ameliorated depression-like symptoms, mitigated hippocampal damage, and reduced pro-inflammatory markers, including NOD-like receptor protein 3, interleukin-1β (IL-1β), and IL-18 by inhibiting the cGAS-STING pathway. Furthermore, H 2 S significantly upregulated autophagy-related proteins (LC3, Beclin-1, and FAM134B) and autophagic vesicles, indicating enhanced ER autophagy. Notably, silencing FAM134B reversed the inhibitory effects of H 2 S on the cGAS-STING pathway, underscoring the pivotal role of ER autophagy in H 2 S-mediated neuroprotection. These findings demonstrate that H 2 S mitigates PSD-induced microglial inflammation and depression-like behaviors by inhibiting the cGAS-STING pathway and promoting ER autophagy, suggesting its potential as a therapeutic strategy for PSD. Further investigation into H 2 S and autophagy-related pathways could reveal novel therapeutic avenues for neuroinflammatory conditions.