PIM-1 exacerbates sepsis-associated encephalopathy via promoting microglia NLRP3 inflammasome activation.

BACKGROUND

Sepsis-associated encephalopathy (SAE) represents one of the most common neurological complications observed in sepsis patients, contributing to both increased mortality and long-term cognitive impairment. Microglial mitochondrial reactive oxygen species (mtROS) overproduction and NLR family pyrin domain-containing 3 (NLRP3) inflammasome activation were key pathological drivers of SAE. Although PIM-1, a serine/threonine kinase, was known to regulate both mtROS generation and NLRP3 signaling, its specific contribution to SAE remained poorly defined.

METHODS

This study established a SAE mouse model using cecal ligation and puncture (CLP) surgery, and screened the differentially expressed gene PIM-1 through immunohistochemistry, GEO database analysis, and etc. An in vitro model was established using Lipopolysaccharide + Adenosine(LPS + ATP) Triphosphate stimulated Mouse Microglia (BV-2), and the regulation mechanism of PIM-1 was analyzed through siRNA interference, RNA-seq, and etc. Potential drug Urolithin B (UB) targeting PIM-1 inhibition was screened through molecular docking, and its inhibitory effect on PIM-1 and therapeutic potential in SAE were evaluated through thermal stability experiments, behavioral experiments, etc.

RESULTS

PIM-1 was upregulated in SAE, which was associated with brain damage. PIM-1 knockdown suppressed microglial activation and reduced inflammatory cytokines release. Further investigation indicated that PIM-1 modulated mtROS generation and facilitated NLRP3 inflammasome activation. Notably, pharmacological inhibition of PIM-1 by UB alleviated SAE both in vivo and in vitro, resulting in improved neuronal damage and cognitive impairment.

CONCLUSION

PIM-1 played a critical role in SAE progression, potentially through its mediation of microglial activation and neuroinflammation via the mtROS/NLRP3 axis. Notably, pharmacological inhibition of PIM-1 with urolithin B significantly alleviated SAE.