MicroRNAs targeting TGFβ signalling underlie the regulatory T cell defect in multiple sclerosis

Area of Science:

• Immunology
• Molecular Biology
• Neuroscience

Background:

• Transforming growth factor beta (TGFβ) signaling is crucial for regulatory T cell (Treg) function.
• Treg dysregulation is implicated in autoimmune diseases like multiple sclerosis (MS).

Purpose of the Study:

• To investigate the role of microRNAs (miRNAs) in Treg defects observed in multiple sclerosis.
• To determine if dysregulated miRNAs targeting TGFβ signaling contribute to MS pathogenesis.

Main Methods:

• miRNA profiling of naïve CD4 T cells from multiple sclerosis patients.
• Analysis of TGFβ signaling components and Treg differentiation capacity.
• Assessment of Treg suppressive function in vitro.

Main Results:

• 19 differentially expressed miRNAs targeting the TGFβ pathway were identified in MS patients.
• MS patients showed reduced TGFβ signaling components in naïve CD4 T cells.
• Overexpressed TGFβ-targeting miRNAs impaired Treg differentiation but retained suppressive function.

Conclusions:

• Elevated TGFβ-targeting miRNAs in MS patients' naïve CD4 T cells dampen TGFβ signaling.
• This miRNA-mediated impairment of Treg development contributes to the reduced Treg repertoire in MS.
• These findings suggest a mechanism linking miRNA dysregulation to multiple sclerosis susceptibility.