DNA hypermethylation during tuberculosis dampens host immune responsiveness

Area of Science:

• Immunology
• Epigenetics
• Infectious Diseases

Background:

• Mycobacterium tuberculosis (M. tuberculosis) employs immune evasion strategies.
• Chronic infections can induce host DNA methylation changes.
• Understanding these mechanisms is crucial for improving tuberculosis (TB) treatment.

Purpose of the Study:

• To investigate DNA methylation patterns in patients with TB.
• To identify specific immune pathways affected by DNA hypermethylation in TB.
• To correlate DNA methylation status with immune responsiveness in TB patients.

Main Methods:

• Methylation-sensitive restriction enzyme-quantitative PCR (MSRE-qPCR) was used.
• DNA methylation status of signaling pathways (IL-2/STAT5, TNF/NF-κB, IFN-γ) was evaluated.
• Immune responsiveness was assessed via cytokine production (IFN-γ, TNF, IL-6, etc.).

Main Results:

• TB patients showed DNA hypermethylation in IL-2/STAT5, TNF/NF-κB, and IFN-γ pathways.
• Genes in the IL-12/IFN-γ pathway (e.g., IL12B, JAK2) were hypermethylated in TB patients.
• DNA hypermethylation correlated with reduced immune cell responsiveness and cytokine production.

Conclusions:

• Immune cells in TB patients display DNA hypermethylation of critical immune genes.
• This epigenetic alteration leads to diminished mycobacteria-specific and non-specific immune responses.
• Targeting DNA methylation could be a strategy to restore host immunity in TB.