Lenalidomide regulates CNS autoimmunity by promoting M2 macrophages polarization

Area of Science:

• Neuroimmunology
• Immunology
• Pharmacology

Background:

• Multiple sclerosis (MS) is a CNS disorder involving leukocyte infiltration and demyelination.
• M2 macrophages show promise in ameliorating experimental autoimmune encephalomyelitis (EAE), an MS model.

Purpose of the Study:

• To investigate lenalidomide's therapeutic potential in EAE by examining its effects on macrophage polarization and immune cell modulation.
• To elucidate the role of IL-10 in lenalidomide's protective mechanisms against EAE.

Main Methods:

• Lenalidomide treatment in EAE mice.
• Macrophage depletion using clodronate liposomes.
• Adoptive transfer of lenalidomide-induced bone marrow-derived macrophages (BMDMs).
• Analysis of immune cell populations (Th1, Th17) and cytokine production (IL-10).
• Assessment of EAE clinical scores and CNS pathology.

Main Results:

• Lenalidomide treatment promoted M2 macrophage polarization and suppressed proinflammatory Th1/Th17 cells.
• Macrophage depletion or transfer abrogated lenalidomide's therapeutic effects.
• IL-10 upregulation was crucial, as IL-10-deficient mice showed exacerbated EAE and lenalidomide treatment was ineffective.
• Lenalidomide enhanced IL-10 secretion, activating STAT3-mediated Ym1 expression.

Conclusions:

• Lenalidomide demonstrates therapeutic potential for MS by promoting M2 macrophages and IL-10 production, thereby inhibiting detrimental immune responses.
• IL-10 is essential for lenalidomide's efficacy in ameliorating EAE.
• Lenalidomide represents a promising therapeutic strategy for multiple sclerosis.