Analysis of gene expression profiles of Enterococcus faecalis induced by type I collagen

Enterococcus faecalis is an etiological agent of endodontic infections. The present study was performed to investigate the gene profiles of E. faecalis induced by type I collagen stimulation. E. faecalis ATCC 19433 was cultivated with [collagen (+)] or without type I collagen [collagen (−)], and transcriptome analysis was performed using high-throughput sequencing technology. A total of 3.6 gb of information was obtained by sequence analysis and 77 differentially expressed genes (DEGs) between the two culture conditions were identified. Among the 77 DEGs, 35 genes were upregulated in collagen (+) E. faecalis, whereas 42 genes were downregulated. Gene Ontology (GO) enrichment analysis was performed and 11 GO terms, including metalloendopeptidase activity (GO:0004222) and two related GO terms (GO:0031012, GO:0044421), were significantly enriched in the set of upregulated genes. We focused on an upregulated DEG belonging to the matrixin metalloprotease gene family, and matrix metalloprotease (MMP) activities of the bacterial cell were examined. The generic MMP, MMP-8, and MMP-9 activities of collagen (+) E. faecalis were significantly higher than those of collagen (−) E. faecalis. These results suggested that contact with type I collagen may alter the gene expression profile of E. faecalis, and upregulation of metalloprotease genes may result in enhanced MMP activities in E. faecalis.