Interferon-β Intensifies Interleukin-23-Driven Pathogenicity of T Helper Cells in Neuroinflammatory Disease

Area of Science:

• Neuroimmunology
• Inflammatory Diseases
• Cellular Immunology

Background:

• Interferon beta (IFN-β) is a common treatment for multiple sclerosis (MS), but 25-40% of patients do not respond.
• IFN-β can exacerbate neuromyelitis optica (NMO), a related neuroinflammatory condition.
• Previous research indicated IFN-β promotes inflammation in T Helper 17 (TH17) cell-mediated diseases via IL-6, yet other studies show it inhibits TH17 cells.

Purpose of the Study:

• To resolve the paradoxical effects of IFN-β on TH17 cell differentiation and function.
• To elucidate the mechanisms behind IFN-β non-responsiveness in MS and NMO patients.
• To identify specific pathways involved in the pathophysiology of IFN-β non-responsive neuroinflammatory diseases.

Main Methods:

• Investigated the effects of IFN-β on distinct stages of TH17 cell development.
• Analyzed cytokine production (IL-17, IL-6, GM-CSF) and transcription factor expression (BLIMP) in differentiating TH17 cells.
• Utilized both NMO patient data and mouse models of TH17-induced disease.

Main Results:

• IFN-β inhibits IL-17 production during early TH17 cell development.
• During late TH17 differentiation, IFN-β synergizes with IL-23 to generate pathogenic T cells.
• These pathogenic cells exhibit both TH1 and TH17 characteristics, with elevated IL-6, GM-CSF, and BLIMP expression.

Conclusions:

• IFN-β exhibits stage-specific, differential effects on TH17 cell development.
• The late-stage pro-inflammatory effects of IFN-β on TH17 cells contribute to the pathophysiology of IFN-β non-responders in MS and NMO.
• Understanding these differential effects clarifies the paradox of IFN-β activity in neuroinflammatory diseases.