AIM2 controls microglial inflammation to prevent experimental autoimmune encephalomyelitis

Area of Science:

• Neuroimmunology
• Inflammation research
• Autoimmune diseases

Background:

• The role of Absent in melanoma 2 (AIM2), an inflammasome sensor, in experimental autoimmune encephalomyelitis (EAE) is not well understood.
• AIM2 is a member of the PYHIN family, known for its involvement in innate immunity and inflammasome activation.

Purpose of the Study:

• To investigate the role of AIM2 in the pathogenesis of EAE.
• To elucidate the underlying molecular mechanisms of AIM2's function in EAE.
• To explore potential therapeutic targets for multiple sclerosis (MS) based on these findings.

Main Methods:

• Utilized a mouse model of EAE to study disease progression.
• Assessed microglia activation and immune cell infiltration into the central nervous system (CNS).
• Investigated the interplay between AIM2, cGAS, DNA-PK, and AKT3 signaling pathways in microglia.

Main Results:

• AIM2 deficiency exacerbated EAE, leading to increased microglia activation and immune cell infiltration.
• AIM2 negatively regulated EAE pathogenesis independently of inflammasome activation.
• AIM2 negatively modulated the DNA-PK-AKT3 pathway in microglia, impacting neuroinflammation induced by cGAS and DNA-PK.
• Administration of a DNA-PK inhibitor ameliorated EAE severity.

Conclusions:

• AIM2 plays a critical, inflammasome-independent role in negatively regulating EAE onset.
• The cGAS and DNA-PK signaling pathways in microglia are key targets for managing neuroinflammation in EAE.
• These findings highlight AIM2 and its associated pathways as potential therapeutic targets for treating heterogeneous forms of MS.