LRP1 expression in microglia is protective during CNS autoimmunity.

Area of Science:

• Neuroimmunology
• Cellular and Molecular Neuroscience

Background:

• Multiple sclerosis (MS) involves autoimmune destruction of central nervous system myelin.
• The role of myeloid cells, particularly microglia, in MS pathogenesis requires further elucidation.
• Low-density lipoprotein receptor-related protein-1 (LRP1) is a scavenger receptor implicated in myelin clearance and inflammation.

Purpose of the Study:

• To investigate the function of LRP1 in myeloid cells within the context of Multiple Sclerosis.
• To determine the specific role of microglial LRP1 in experimental autoimmune encephalomyelitis (EAE), an MS animal model.

Main Methods:

• Analysis of LRP1 expression in MS lesions.
• Utilizing genetic mouse models with LRP1 deletion in microglia and peripheral macrophages.
• Assessment of EAE progression and cellular phenotypes, including inflammatory mediator production and NF-κB activation.

Main Results:

• LRP1 expression is elevated in MS lesions.
• Deletion of LRP1 in microglia, but not peripheral macrophages, exacerbates EAE.
• Microglia lacking LRP1 exhibit a pro-inflammatory phenotype with increased TNF-α production and enhanced NF-κB activation.
• LRP1 acts as an inhibitor of NF-κB activation via a MyD88-dependent pathway.

Conclusions:

• Microglial LRP1 plays a critical neuroprotective role by maintaining an anti-inflammatory state.
• LRP1 function in microglia is essential for mitigating disease severity in EAE and potentially in MS.
• Targeting LRP1 in microglia may offer a therapeutic strategy for Multiple Sclerosis.