Brain endothelial GSDMD activation mediates inflammatory BBB breakdown

The blood-brain barrier (BBB) protects the central nervous system (CNS) from external assaults by pathogenic or harmful substances. BBB impairment frequently occurs during infection, inflammatory, or other pathological conditions, which causes or exacerbates a wide range of CNS diseases. Using single cell transcriptomics, we show in this study that during systemic LPS challenges, brain endothelial cells undergo Gsdmd-mediated pyroptosis and impair the integrity of the BBB, leading to profound changes in the transcriptomic landscape of brain parenchymal populations. Analyses of the scRNA-seq dataset reveal that brain endothelial cells responded strongly to systemic LPS challenge. Further analyses of the transcriptional signatures revealed that the brain parenchymal populations displayed heterogeneous responses to BBB leakage accompanied by systemic inflammation. Adult (6~8w) wild type or Gsdmd-/- mice were subjected to either Dulbecco's phosphate buffer saline (Ctrl) or 40mg/kg lipopolysaccharide (LPS) for ~8 hours, from the parenteral route (i.p.). Single cells from the motor cortex were dissociated and collected for scRNA-seq and sequenced using the 10X Genomics Chromium platform.