The effect of a single nucleotide polymorphism in the matrix metalloproteinase-1 (MMP-1) promoter on force-induced MMP-1 expression in human periodontal ligament cells

Matrix metalloproteinase-1 (MMP-1) 1G/2G (-1,607) polymorphisms have been identified and shown to influence the transcription of the MMP-1 gene. In order to compare the expression of MMP-1 with different MMP-1 gene promoter alleles after force loading, human periodontal ligament (PDL) cells were cultured and genotyped into three alleles by polymerase chain reaction and restriction endonuclease cleavage. The three genotypes of PDL cells were centrifuged and the expression of MMP-1 mRNA and protein were determined by reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. The results showed that centrifugal force upregulated the expression of both MMP-1 mRNA and protein in all three genotypes of PDL cells. The induction of MMP-1 by force was significantly greater in cells with a 2G/2G genotype or a 1G/2G genotype than in cells homozygous for the 1G allele. The MMP-1 mRNA and protein levels were significantly higher for cells with the 2G allele than for cells with the 1G/2G allele or the 1G allele. These results suggest that a single nucleotide polymorphism in the -1,607 bp MMP-1 promoter region might be associated with the difference observed in the endogenous expression of MMP-1 in PDL cells under mechanical force.