Novel mutations in TLR genes cause hyporesponsiveness to Mycobacterium avium subsp. paratuberculosis infection

Area of Science:

• Immunology
• Genetics
• Microbiology

Background:

• Toll-like receptors (TLRs) are crucial for detecting pathogen-associated molecular patterns (PAMPs).
• Genetic variations in TLR1, TLR2, and TLR4 can affect pathogen recognition and immune responses to bacteria.

Purpose of the Study:

• To investigate the association between TLR gene mutations and susceptibility to Mycobacterium avium subsp. paratuberculosis (MAP) infection.
• To identify novel mutations in TLR genes and their functional impact on MAP recognition.

Main Methods:

• Genomic analysis to identify novel mutations in TLR1, TLR2, and TLR4 genes.
• In vitro experiments using mutant and wild-type monocyte-derived dendritic cells (moDCs) challenged with MAP.
• Cytokine expression analysis (IL-4, IL-8, IL-10, IL-12, IFN-gamma).
• In silico analysis of TLR ectodomains (ECD) and leucine-rich repeat (LRR) motifs.

Main Results:

• Novel mutations in TLR1 (Ser150Gly, Val220Met) and TLR2 (Phe670Leu) were statistically correlated with impaired recognition of MAP.
• Mutant moDCs showed altered cytokine expression profiles compared to wild-type cells after MAP challenge.
• In silico analysis revealed polymorphism and irregularities in the central ECD and LRR motifs of TLR1 and TLR4.

Conclusions:

• Specific mutations in TLR1 and TLR2 hinder the recognition of MAP components.
• Critical amino acid positions within TLR1 and TLR4 LRR motifs significantly influence pathogen recognition.
• The study identifies novel TLR mutations associated with MAP infection susceptibility.