An rs4705342 T>C polymorphism in the promoter of miR-143/145 is associated with a decreased risk of ischemic stroke

The expression of miR-143/miR-145 was up-regulated in ischemic stroke (IS), which may be used as biomarkers and/or therapeutic targets for IS. We aimed to investigate the association of rs4705342 and rs4705343 polymorphisms in the promoter of miR-143/145 with risk of IS. The study population comprised 445 patients with IS and 518 controls. The rs4705342 genotype was analyzed by using a TaqMan Assay and the rs4705343 genotype was determined by using a polymerase chain reaction-restriction fragment length polymorphism assay. Relative expression of miR-143/miR-145 was measured by quantitative real-time PCR. We found that the rs4705342 was associated with a decreased risk of IS (TC vs. TT: adjusted OR = 0.74, 95% CI, 0.57-0.97; CC vs. TT: adjusted OR = 0.53, 95% CI, 0.34-0.83). Haplotype analysis showed that the TC haplotype was associated with an increased risk of IS risk (OR = 1.33, 95% CI, 1.01-1.75), whereas the CT haplotype was associated with a decreased risk of IS risk (OR = 0.68, 95% CI, 0.50-0.92). Importantly, patients carrying the rs4705342TC/CC genotypes had a lower level of miR-145 (P = 0.03). We found for the first time that the rs4705342 CC was a protective factor for IS, probably by reducing the level of miR-145.