Toll-like receptors TLR1, TLR2 and TLR4 gene mutations and natural resistance to Mycobacterium avium subsp. paratuberculosis infection in cattle

• Published in: Veterinary immunology and immunopathology Vol. 128; no. 4; pp. 381 - 388
• Main Authors: Mucha, R., Bhide, M.R., Chakurkar, E.B., Novak, M., Mikula, I.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15-04-2009; Amsterdam: Elsevier
• Subjects: Amino Acid Motifs - immunology; Amino Acid Sequence; animal genetics; Animals; Base Sequence; binding proteins; Cattle; cattle diseases; Cattle Diseases - epidemiology; Cattle Diseases - genetics; Cattle Diseases - immunology; Cattle Diseases - microbiology; disease resistance; DNA - chemistry; DNA - genetics; Female; genes; genetic correlation; genetic polymorphism; Genetic Predisposition to Disease; Genetic Variation; genotype; immunity; linkage (genetics); missense mutation; molecular genetics; Molecular Sequence Data; Mutation; Mutation, Missense; Mycobacterium avium; Mycobacterium avium subsp. paratuberculosis; Mycobacterium avium subsp. paratuberculosis - immunology; Natural resistance; paratuberculosis; Paratuberculosis - epidemiology; Paratuberculosis - genetics; Paratuberculosis - immunology; pathogen-associated molecular patterns; pathogenesis; pattern recognition receptors; Point Mutation; Polymerase Chain Reaction - veterinary; Polymorphism, Single Nucleotide; Prevalence; receptors; Sequence Alignment; Slovakia - epidemiology; Toll like receptors; Toll-like receptor; Toll-Like Receptors - genetics; Toll-Like Receptors - immunology; Slovakia; Natural resistance; Mycobacterium avium subsp. paratuberculosis; Mutation; MAP; Toll-like receptor
• ISSN: 0165-2427; 1873-2534
• DOI: 10.1016/j.vetimm.2008.12.007

Toll like receptors (TLRs) are a class of pattern recognition receptors belonging to the innate immune system. Mutations in the protein coding region of TLRs are associated with altered responsiveness to pathogen-associated molecular patterns (PAMPs). A search was performed for novel mutations in bovine TLR1, TLR2 and TLR4 genes associated with the
Mycobacterium avium subsp.
paratuberculosis (MAP) infection. The work was also focused on the assessment of linkage between well known mutations in TLR genes (TLR2: Arg677Trp, Pro681His and Arg753Gln; TLR4: Asp299Gly and Thr399Ile), and the susceptibility of cattle to MAP infection. Detection of MAP infection in cattle population (
n
=
711) was based on
IS900 PCR, which revealed 22.50% (
n
=
160) MAP positivity. Known mutations in TLR2 and TLR4 genes were not found in cattle population. A novel mutation Val220Met was associated (Odd's ratio, OR-3.459) with increased susceptibility to MAP infection. Toll/interleukin-1 receptor (TIR) domain of TLR2 was screened for the presence of mutations, wherein a novel Ile680Val mutation was linked with MAP infection.
In silico analysis of the bovine TLR4 ectodomain (ECD) revealed the polymorphic nature of the central ECD and irregularities in the central LRR motifs. LRR11 of the TLR4 showed five missense mutations possibly linked with the increased susceptibility to MAP infection. The most critical position that may alter the pathogen recognition of TLR molecule was 4th residue downstream to LRR domain. Two such missense mutations in TLR4 (Asp299Asn downstream to LRR11, and Gly389Ser downstream to LRR15) were associated with MAP infection. Briefly, the work describes novel mutations in the bovine TLRs and presents their association with the MAP infection.