DDIT4 and Associated lncDDIT4 Modulate Th17 Differentiation through the DDIT4/TSC/mTOR Pathway

Area of Science:

• Immunology
• Molecular Biology
• Genetics

Background:

• Inflammation in autoimmune diseases like multiple sclerosis (MS) is linked to aberrant Th17 cell differentiation.
• The precise mechanisms driving Th17 cell-mediated autoimmunity remain unclear.

Purpose of the Study:

• To investigate the inhibitory roles of DNA-damage-inducible transcript 4 (DDIT4) and its associated long noncoding RNA (lncDDIT4) in Th17 cell differentiation.
• To explore the relationship between lncDDIT4, DDIT4, and the DDIT4/mTOR pathway in the context of MS.

Main Methods:

• Microarray analysis and real-time quantitative PCR to assess lncDDIT4 and DDIT4 expression in MS patients and healthy controls.
• Manipulation of lncDDIT4 and DDIT4 expression in naive CD4+ T cells from MS patients to observe effects on Th17 cell differentiation.
• Assessment of the DDIT4/mTOR pathway activation.

Main Results:

• lncDDIT4 and DDIT4 mRNA expression were significantly higher in PBMCs and CD4+ T cells of MS patients compared to controls.
• Overexpression of lncDDIT4 inhibited IL-17 transcription by increasing DDIT4 expression and decreasing DDIT4/mTOR pathway activation.
• Silencing lncDDIT4 enhanced Th17 differentiation, an effect dependent on DDIT4 expression and DDIT4/mTOR pathway activation.

Conclusions:

• lncDDIT4 acts as a negative regulator of Th17 cell differentiation.
• The inhibitory function of lncDDIT4 is mediated through direct targeting of DDIT4 and modulation of the DDIT4/mTOR pathway.
• These findings suggest lncDDIT4 and DDIT4 as potential therapeutic targets for MS and other Th17 cell-driven autoimmune diseases.