Downregulation of odontogenic ameloblast-associated protein in the progression of periodontal disease affects cell adhesion, proliferation, and migration

ODAM is important in cell adhesion, proliferation, and migration, and its downregulation may contribute to periodontitis progression in humans.

This work aimed to examine changes in odontogenic ameloblast-associated protein (ODAM) expression during the progression of periodontal disease and to investigate the effect of ODAM deficiency in vitro by RNA sequencing. Design: Gingival tissue samples were collected from three groups, including healthy control, gingivitis and periodontitis patients, and ODAM expression was assessed by immunohistochemistry and quantitative reverse transcription PCR (qRT-PCR). Then, an Odam-knockdown cell line was established by lentiviral infection of small guide RNAs (sgRNAs) into an immortalized ameloblast-lineage cell line. RNA sequencing was carried out in Odam-knockdown and empty lentiviral vector-transfected cells. Differentially expressed genes were compared between these two cell groups to analyze functional enrichment, and a protein-protein interaction network was built.

ODAM expression levels in gingival tissue samples were significantly lower in patients with periodontitis than in healthy controls as determined by immunohistochemistry and qRT-PCR. Transcriptomic analysis of Odam-knockdown cells identified 2801 differentially expressed genes, which were enriched in cell-substrate adhesion, proliferation, and migration pathways. The expression of a core of differentially expressed genes was confirmed by qRT-PCR in Odam-knockdown cells and by immunohistochemistry in clinical samples. Knocking down Odam significantly reduced cell adhesion but increased cell proliferation and migration capacity in vitro. Conclusions: ODAM is important in cell adhesion, proliferation, and migration, and its downregulation may contribute to periodontitis progression in humans.