[PTPRO inhibitor alleviates cytoskeletal rearrangement and pyroptosis in brain microvascular endothelial cells in sepsis-associated encephalopathy via PI3K/AKT-related signaling].

Objective Sepsis-associated encephalopathy (SAE) is a common and severe complication of sepsis and is closely associated with blood-brain barrier (BBB) dysfunction and brain microvascular endothelial cell injury. Protein tyrosine phosphatase receptor type O (PTPRO) plays an important role in inflammatory signal transduction and cellular functional regulation; however, its role in regulating brain endothelial barrier function during SAE remains unclear. This study aimed to investigate the effects of a PTPRO inhibitor on cytoskeletal remodeling and pyroptosis-related molecular events in brain microvascular endothelial cells and to explore the underlying molecular mechanism. Methods A mouse SAE model was established by intraperitoneal injection of lipopolysaccharide (LPS). Brain inflammatory cytokines were measured, and BBB permeability was evaluated by detecting albumin leakage and Evans Blue extravasation. In vitro, mouse brain microvascular endothelial bEnd.3 cells were stimulated with LPS. Immunofluorescence, transendothelial electrical resistance (TEER), and Western blotting were used to detect PTPRO expression, filamentous actin (F-actin) remodeling, monolayer barrier function, caspase-11/gasdermin D (GSDMD)-related pyroptotic molecular events, and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) phosphorylation. PTPRO siRNA was used to verify the pharmacological inhibition results. Results LPS significantly increased interleukin-1β and interleukin-6 levels in mouse brain tissues and enhanced albumin leakage and Evans Blue extravasation. Pretreatment with the PTPRO inhibitor attenuated LPS-induced BBB permeability damage. In vitro, LPS markedly upregulated PTPRO expression in bEnd.3 cells, reduced TEER, induced F-actin remodeling, cell contraction, and intercellular gap formation, and increased caspase-11 and GSDMD-N levels. PTPRO inhibition or PTPRO siRNA intervention reversed these changes to varying degrees and was accompanied by reduced phosphorylation of PI3K and AKT. ConclusionPTPRO inhibition alleviates LPS-induced cytoskeletal remodeling, barrier dysfunction, and caspase-11/GSDMD-related pyroptotic molecular events in brain microvascular endothelial cells, possibly through PI3K/AKT-related signaling changes.