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

Objective: 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.

Results: 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.