Associations of Toll-like receptor 3 gene single nucleotide polymorphisms with cataract

The aim of this study was to investigate the expression of Toll-like receptor 3 (TLR3) gene in the anterior capsule of cataract patients and to explore the correlations of its polymorphisms with the incidence of cataract.

A total of 80 cataract patients (Cataract group) and 38 clear lenses (Control group) were selected as research subjects. Western blotting assay was used to detect the protein expression of TLR3 in Cataract group and Control group. Subsequently, single nucleotide polymorphisms (SNPs) rs128912, rs100321 and rs129103 in the promoter region of TLR3 gene were classified by conformation-difference gel electrophoresis. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to test the correlations of different gene polymorphisms with the protein expression of TLR3. Meanwhile, chi-square test was applied to check whether the distribution frequency of TLR3 genotypes conforms to the Hardy-Weinberg genetic equilibrium law. Furthermore, the associations of alleles and gene polymorphisms of TLR3 with the incidence of cataract were analyzed.

Western blotting results found that the protein expression level of TLR3 in the anterior capsule in Cataract group was significantly higher than that in Control group (p<0.05). Hardy-Weinberg genetic equilibrium analysis showed that three TLR3 gene polymorphisms conformed to the genetic equilibrium distribution (p>0.05). Subsequent results demonstrated that the protein expression level of TLR3 in cataract patients with genotype TT of TLR3 gene polymorphism rs128912 was remarkably higher than that in patients with genotypes AA and AT (p<0.05). Moreover, the results of genetic association analysis manifested that only gene polymorphism rs128912 and its alleles were associated with cataract (p<0.05). However, gene polymorphisms rs100321 and rs129103 and their alleles were not correlated with the incidence of cataract (p>0.05).

TLR3 was highly expressed in the anterior capsule of patients with cataract. In addition, rs128912 in the promoter region of TLR3 gene was correlated with the incidence of cataract, while rs100321 and rs129103 were not associated with the incidence of cataract.