Objective This study aims to investigate possible hub genes,associated pathways,and transcription fac-tors between chronic periodontitis(CP)and Parkinson's disease(PD).Methods Gene expression profiles of CP(GSE16134,GSE23586,and GSE10334)and PD(GSE20141 and GSE49036)were downloaded from the gene expres-sion omnibus(GEO)database for differential expression analysis and functional clustering analysis.The protein-protein interaction(PPI)network was constructed,and hub genes were screened by four topological analysis algorithms and modular segmentation.Functional clustering analysis was performed.The hub genes were validated by external datasets of CP and PD,and causal relation was further assessed by Mendelian randomization(MR).Results After merging the data,1 211 differentially expressed genes(DEGs)were screened in the CP datasets;of which,551 were upregulated and 660 were downregulated.A total of 2 407 DEGs were screened in the PD dataset,of which,1 438 were upregulated and 969 were downregulated.The PPI network included 145 nodes and 126 edges.Four hub genes(FCGR3B,PRF1,IL18,and CD33)and three transcription factors(HSF1,HSF2,and HSF4)were finally screened.The relevant pathway was pre-dominantly natural killer(NK)cell-mediated toxic effects.The MR results suggest a possible positive causal relationship between CP and the risk of developing PD.Conclusion This study indicated the probably shared pathophysiology and possible causal relationship between CP and PD and may offer novel concepts and therapeutic targets for future mecha-nistic investigations.

OBJECTIVES: To investigate possible cross-talk genes, associated pathways, and transcription factors between chronic periodontitis (CP) and chronic obstructive pulmonary disease (COPD). METHODS: The gene expression profiles of CP (GSE10334 and GSE16134) and COPD (GSE76925) were downloaded from the GEO database. Differential expression and functional clustering analyses were performed. The protein‑protein interaction (PPI) network was constructed. The core cross-talk genes were filtered using four topological analysis algorithms and modular segmentation. Then, functional clustering analysis was performed again. RESULTS: GSE10334 detected 164 differentially expressed genes (DEGs) (119 upregulated and 45 downregulated). GSE16134 identified 208 DEGs (154 upregulated and 54 downregulated). GSE76925 identified 1 408 DEGs (557 upregulated and 851 downregulated). The PPI network included 21 nodes and 20 edges. The final screening included seven cross-talk genes: CD79A, FCRLA, CD19, IRF4, CD27, SELL, and CXCL13. Relevant pathways included primary immunodeficiency, the B-cell receptor signaling pathway, and cytokine-cytokine receptor interaction. CONCLUSIONS This study indicates the probability of shared pathophysiology between CP and COPD, and their cross-talk genes, associated pathways, and transcription factors may offer novel concepts for future mechanistic investigations.
Humans ; Chronic Periodontitis/genetics* ; Gene Regulatory Networks ; Gene Expression Profiling ; Protein Interaction Maps/genetics* ; Pulmonary Disease, Chronic Obstructive/genetics*