Erbin protects against sepsis-associated encephalopathy by attenuating microglia pyroptosis via IRE1α/Xbp1s-Ca2+ axis

Background Microglia pyroptosis-mediated neuroinflammation is thought to be the crucial pathogenesis of sepsis-associated encephalopathy (SAE). Erbin has been reported to be associated with various inflammatory diseases. However, the role of Erbin in SAE and the relationship between Erbin and microglia pyroptosis are unknown. In this study, we investigated the promising role and underlying molecular mechanism of Erbin in the regulation of microglia pyroptosis. Methods WT and Erbin knockout mice underwent cecum ligation perforation (CLP) to induce SAE. Primary mouse microglia and BV2 cells were treated with LPS/nigericin in vitro. Behavioral tests were performed to evaluate cognitive function. Nissl staining and transmission electron microscopy were used to assess histological and structural lesions. ELISA and qPCR were carried out to detect neuroinflammation. Western blot and immunofluorescence were used to analyze protein expression. Flow cytometry and confocal microscopy were utilized to observe the Ca2+ changes in the cytoplasm and endoplasmic reticulum (ER). To further explore the underlying mechanism, STF083010 was administered to block the IRE1α/Xbp1s pathway. Results Erbin deletion resulted in more pronounced neuronal damage and cognitive impairment in mice that underwent CLP. Erbin knockout promoted microglial pyroptosis and inflammatory cytokines secretion in vivo and in vitro, which was mediated by activation of the IRE1α/Xbp1s. Treatment with the selective inhibitor STF083010 significantly inhibited IRE1α/Xbp1s pathway activity, decreased intracytoplasmic Ca2+, attenuated microglial pyroptosis, reduced pro-inflammatory cytokine secretion, lessened neuronal damage, and improved cognitive function. Conclusions In SAE, Erbin inhibits IRE1/Xbp1s pathway activity and reduces the ER Ca2+ influx to the cytoplasm, reducing microglial pyroptosis.