Pathway Analyses Identify Novel Variants in the WNT Signaling Pathway Associated with Tuberculosis in Chinese Population

Tuberculosis remains a global public health problem, and its immunopathogenesis is still poorly understood. In this study, 25 single nucleotide polymorphisms (SNPs) in the WNT pathway were evaluated in relation to tuberculosis risk in a Chinese Han discovery set, and 6 candidate susceptible SNPs were further validated in a Chinese Tibetan cohort. Luciferase reporter assay, RT-qPCR and Western blot were used to assess the functionality of the important WNT polymorphisms. Five polymorphisms were associated with tuberculosis susceptibility after Bonferroni correction: SFRP1 rs4736958, CTNNB1 rs9859392, rs9870255 and rs3864004 showed decreased tuberculosis risk; SFRP1 rs7832767 was related to an increased risk (OR = 1.81, 95% CI = 1.30–2.52, p = 0.010). Patients with TT genotype of rs4736958 and rs7832767 correlated with higher CRP concentrations (p = 0.003, <0.001, respectively). Functional assays revealed that mutant alleles of rs9859392 (G), rs9870255 (C) and rs3864004 (A) were associated with significantly decreased transcriptional activity, lower CTNNB1 mRNA expression and p-β-catenin level, which were consistent with their effects of decreasing TB risk. Our results provide evidences that WNT pathway polymorphisms influence tuberculosis susceptibility and host immune response to Mycobacterium tuberculosis, suggesting that these variations may serve as novel markers for identifying the risk of developing tuberculosis.