STAT1 Contributes to Microglial/Macrophage Inflammation and Neurological Dysfunction in a Mouse Model of Traumatic...

Area of Science:

• Neuroscience
• Immunology
• Pharmacology

Background:

• Traumatic brain injury (TBI) causes significant brain inflammation, worsening secondary injury and hindering repair.
• Microglia and macrophages (Mi/MΦ) are key inflammatory cells in the brain post-TBI, but their plasticity remains therapeutically untapped.
• Targeting the functional phenotype of Mi/MΦ is crucial for developing effective TBI treatments.

Purpose of the Study:

• To investigate the role of the transcription factor STAT1 in mediating pro-inflammatory responses of Mi/MΦ after TBI.
• To evaluate STAT1 as a potential therapeutic target for mitigating brain inflammation and improving outcomes following TBI.
• To assess the efficacy of fludarabine, a STAT1 inhibitor, as a novel immunomodulatory therapy for TBI.

Main Methods:

• Utilized a controlled cortical impact model of TBI in adult male mice.
• Administered fludarabine, a selective STAT1 inhibitor, intraperitoneally post-TBI.
• Generated mice with tamoxifen-induced selective knockout of STAT1 in Mi/MΦ (STAT1 mKO) to assess cell-specific effects.

Main Results:

• TBI induced significant upregulation of STAT1 in brain Mi/MΦ at the subacute injury stage.
• Fludarabine treatment markedly reduced pro-inflammatory Mi/MΦ responses and overall brain inflammation.
• STAT1 knockout in Mi/MΦ (STAT1 mKO) reduced long-term neurological deficits and brain lesion size.
• Short-term fludarabine treatment led to lasting TBI outcome improvements, an effect abolished in STAT1 mKO mice.

Conclusions:

• STAT1 is a critical determinant of the pro-inflammatory phenotype in brain Mi/MΦ following TBI.
• STAT1 inhibition, particularly with fludarabine, shows significant therapeutic potential for TBI.
• Targeting STAT1 offers a promising strategy for immunomodulatory therapy to improve TBI recovery.