Identification of key genes and pathways for peri-implantitis through the analysis of gene expression data

The present study attempted to identify potential key genes and pathways of peri-implantitis, and to investigate the possible mechanisms associated with it. An array data of GSE57631 was downloaded, including six samples of peri-implantitis tissue and two samples of normal tissue from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) in the peri-implantitis samples compared with normal ones were analyzed with the limma package. Moreover, Gene Ontology annotation and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses for DEGs were performed by DAVID. A protein-protein interaction (PPI) network was established using Cytoscape software, and significant modules were analyzed using Molecular Complex Detection. A total of 819 DEGs (759 upregulated and 60 downregulated) were identified in the peri-implantitis samples compared with normal ones. Moreover, the PPI network was constructed with 413 nodes and 1,114 protein pairs. Heat shock protein HSP90AA1 (90 kDa a, member 1), a hub node with higher node degrees in module 4, was significantly enriched in antigen processing, in the presentation pathway and nucleotide-binding oligomerization domain (NOD)-like receptor-signaling pathway. In addition, nuclear factor-kappa-B1 (NFKB1) was enriched in the NOD-like receptor-signaling pathway in KEGG pathway enrichment analysis for upregulated genes. The proteasome is the most significant pathway in module 1 with the highest P-value. Therefore, the results of the present study suggested that HSP90AA1 and NFKB1 may be potential key genes, and the NOD-like receptor signaling pathway and proteasome may be potential pathways associated with peri-implantitis development.