Impact of DEFB1 gene regulatory polymorphisms on hBD-1 salivary concentration

Abstract

ObjectivesHuman β-defensin 1 (hBD-1) is an antimicrobial peptide involved in epithelial defence of various tissues, also present in the saliva. Individual genetic variations within the DEFB1 gene, encoding for hBD-1, could influence gene expression and protein production. DesignThree DEFB1 polymorphisms at 5′ untranslated region (UTR), −52G>A (rs1799946), −44C>G (rs1800972) and −20G>A (rs11362), and two polymorphisms at DEFB1 3′ UTR, c*5G>A (rs1047031) and c*87A>G (rs1800971), were analysed by direct sequencing and correlated with hDB-1 salivary concentration (tested with enzyme-linked immunosorbent assay (ELISA)) in 40 healthy subjects. ResultsSignificant associations were found between individuals presenting different DEFB1 polymorphisms at positions −52 and −44 of the gene and hBD-1 salivary concentrations: −52 G/G carriers had higher levels of protein than G/A and A/A; −44C/G subjects showed a higher protein concentration than homozygous wild-type C/C. For the −20G>A, c*5G>A and c*87A>G polymorphisms, no statistically significant differences were found. Combined haplotype analysis confirmed the results obtained considering the single-nucleotide polymorphisms (SNPs) singularly. ConclusionPolymorphisms in the DEFB1 gene influence hBD-1 production and, therefore, could modify the innate immune system responses and, consequently, the oral health.