Precise nanodelivery of screened compounds alleviates sepsis-associated encephalopathy by targeting microglial ANXA2.

Sepsis frequently induces sepsis-associated encephalopathy (SAE), which lacks targeted therapies and often results in persistent neurobehavioral deficits. Here, we developed a translational pipeline integrating target discovery, small-molecule screening, formulation engineering, targeted delivery, and in vivo mechanistic validation to establish a microglial neuroinflammation-centered SAE intervention. Integrative transcriptomic analysis of septic patient brain tissue (GSE135838), combined with weighted gene co-expression network analysis (WGCNA), identified Annexin A2 (ANXA2) as a microglia-associated candidate linked to SAE. In cecal ligation and puncture (CLP) mice, Anxa2 was markedly upregulated in the hippocampus and enriched in microglia. Mechanistically, small interfering RNA (siRNA)-mediated Anxa2 silencing in lipopolysaccharide (LPS)-stimulated BV2 and primary microglia inhibited nuclear factor kappa B (NF-κB) activation, reduced M1-like polarization and cytokine release, and alleviated neuronal apoptosis in co-culture. Screening of the Traditional Chinese Medicine Systems Pharmacology Database (TCMSP) combined with high-throughput surface plasmon resonance imaging (SPRi) identified evodiamine as a high-affinity ANXA2 binder, further supported by molecular dynamics simulations, drug-likeness assessment, and absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiling. To improve efficacy, enhance blood-brain barrier (BBB) penetration, and reduce potential cardiotoxicity, we engineered an Angiopep-2/phosphatidylserine dual-modified evodiamine-loaded liposome (L-A-P@E). In SAE mice, L-A-P@E improved anxiety-like behavior and cognition, attenuated hippocampal neuroinflammation and neuronal apoptosis, and suppressed microglial ANXA2/NF-κB signaling without detectable systemic immunogenicity. Knockdown-rescue assays using a triple-mutant Anxa2 construct and AAV-mediated hippocampal Anxa2 overexpression confirmed that evodiamine's therapeutic effects depended on the ANXA2-binding pocket and ANXA2/NF-κB signaling. These findings identify microglial ANXA2/NF-κB as a druggable SAE target and support targeted nanodelivery for mechanism-based therapy.