OBJECTIVE: To investigate the effect of Porphyromonas gingivalis (Pg) infection on IFNGR1 palmitoylation and biological behaviors of esophageal squamous cell carcinoma (ESCC) cells and the clinical implications. METHODS: The expression levels of IFNGR1 protein in ESCC cell lines KYSE30 and KYSE70 were detected using Western blotting at 24 and 48 h after Pg infection, and 2-BP was used to detect IFNGR1 palmitoylation in the cells. KYSE70 cells with wild-type IFNGR1 (IFNGR1-WT cells) and with IFNGR1-C122A palmitoylation site mutation induced by site-specific mutagenesis (IFNGR1-C122A cells) were both infected with Pg, and the changes in palmitoylation of IFNGR1-C122A were analyzed using immunofluorescence and Click-iT assays. The changes in proliferation, migration and invasion ability of the infected cells were evaluated using plate cloning assay, scratch assay and Transwell assay, and IFNGR1 co-localization with lysosomal marker LAMP2 was dected using immunofluorescence assay. Immunohistochemistry was used to detect Pg infection and IFNGR1 protein expression in 50 ESCC tissues, and their correlation with the clinicopathological characteristics and survival outcomes of the patients was analyzed. RESULTS: Pg infection down-regulated the protein expression of IFNGR1 in ESCC and promoted IFNGR1 palmitoylation at site 122. In IFNGR1-WT cells, Pg infection significantly enhanced cell proliferation, migration and invasion (P < 0.05). Similarly, Pg also significantly promoted proliferation, migration and invasion of IFNGR1-C122A cells, but to a lesser extent as compared with the wild-type cells (P < 0.05). Immunofluorescence assay showed that Pg and ZDHHC3 promoted IFNGR1 degradation within the lysosome. Immunohistochemical studies of the ESCC tissue samples showed a negative correlation between IFNGR1 and Pg expression, and a reduced IFNGR1 expression was correlated with a poorer survival outcome of the patient. CONCLUSION Pg infection enhances IFNGR1 palmitoylation to promote progression of ESCC, and elimination of Pg and inhibiting IFNGR1 palmitoylation may effectively control ESCC progression.
Humans ; Esophageal Neoplasms ; Porphyromonas gingivalis ; Lipoylation ; Esophageal Squamous Cell Carcinoma ; Lysosomes

OBJECTIVE: To describe the submucosal microbial profiles of peri-implantitis and healthy implants, and to explore bacteria that might be correlated with clinical parameters. METHODS: In the present cross-sectional study, 49 patients were recruited. Each patient contributed with one implant, submucosal biofilms were collected from 20 healthy implants and 29 implants with peri-implantitis. DNA was extracted and bacterial 16S ribosomal RNA (16S rRNA) genes were amplified. Submucosal biofilms were analyzed using 16S rRNA sequencing at Illumina MiSeq platform. Differences between the groups were determined by analyzing α diversity, microbial component and microbial structure. The potential correlation between the bacteria with pocket probing depth (PPD) of peri-implant calculated by Spearman correlation analysis. RESULTS: The α diversity of submucosal microbial of health group was significantly lower than that in peri-implantitis group (Chao1 index: 236.85±66.13 vs. 150.54±57.43, P < 0.001; Shannon index: 3.42±0.48 vs. 3.02±0.65, P=0.032). Principal coordinated analysis showed that the submucosal microbial structure had significant difference between healthy and peri-implantitis groups [R²=0.243, P=0.001, analysis of similarities (ANOSIM)]. Compared with healthy implants, relative abundance of periodontal pathogens were higher in peri-implantitis, including members of the red complex (Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola) and some members of orange complex (Precotella intermedia, Eubacterium nodatum, Parvimonas micra), as well as some new periodontal pathogens, such as Fillifactor alocis, Fretibacterium fastidiosum, Desulfobulbus sp._HMT_041, and Porphyromonas endodontalis. Spearman correlation analysis revealed that the relative abundance of Treponema denticola (r=0.686, P < 0.001), Tannerella forsythia (r=0.675, P < 0.001), Fretibacterium sp. (r=0.671, P < 0.001), Desulfobulbus sp._HMT_041 (r=0.664, P < 0.001), Filifactor alocis (r=0.642, P < 0.001), Fretibacterium fastidiosum (r=0.604, P < 0.001), Porphyromonas gingivalis (r=0.597, P < 0.001), Porphyromonas endodontalis (r=0.573, P < 0.001) were positive correlated with PPD. While the relative abundance of Rothia aeria (r=-0.615, P < 0.001) showed negatively correlation with PPD. CONCLUSION Marked differences were observed in the microbial profiles of healthy implants and peri-implantitis. The members of red and orange complex as well as some new periodontal pathogens seem to play an important role in peri-implant disease. Compared with healthy implants, the submucosal microbial of peri-implantitis were characterized by high species richness and diversity.
Humans ; Peri-Implantitis/microbiology* ; Cross-Sectional Studies ; RNA, Ribosomal, 16S/genetics* ; Bacterial Load ; Porphyromonas gingivalis ; Dental Implants

OBJECTIVE: To explore the molecular mechanisms of Porphyromonas gingivalis infection-induced umbilical vein endothelial barrier dysfunction in vitro. METHODS: Human umbilical vein endothelial cells (HUVECs) were cultured in vitro, and after the formation of the endothelial barrier, the cells were infected with P. gingivals at a multiplicity of infection (MOI). The transepithelial electrical resistance (TEER) of the cell barrier was measured, and FITC-dextran trans-endothelial permeability assay and bacterial translocation assay were performed to assess the endothelial barrier function. The expression levels of cell junction proteins including ZO-1, occludin and VE-cadherin in the cells were examined by qRT-PCR and Western blotting. RESULTS: In freshly seeded HUVECs, TEER increased until reaching the maximum on Day 5 (94 Ωcm²), suggesting the formation of the endothelial barrier. P. gingivals infection caused an increase of the permeability of the endothelial barrier as early as 0.5 h after bacterial inoculation, and the barrier function further exacerbated with time, as shown by significantly lowered TEER, increased permeability of FITC-dextran (40 000/70 000), and increased translocation of SYTO9-E. coli cross the barrier. MTT assay suggested that P. gingivals infection did not significantly affect the proliferation of HUVECs (P>0.05), but in P. gingivalsinfected cells, the expressions of ZO-1, occludin and VE-cadherin increased significantly at 24 and 48 h after bacterial inoculation (P < 0.05). CONCLUSION P. gingivals may disrupt the endothelial barrier function by down-regulating the expressions of the cell junction proteins (ZO-1, occludin, VE-cadherin) and increasing the permeability of the endothelial barrier.
Humans ; Cadherins/metabolism* ; Escherichia coli/metabolism* ; Human Umbilical Vein Endothelial Cells/metabolism* ; Occludin ; Porphyromonas gingivalis/metabolism* ; Umbilical Veins/metabolism*

Bacteremia induced by periodontal infection is an important factor for periodontitis to threaten general health. P. gingivalis DNA/virulence factors have been found in the brain tissues from patients with Alzheimer's disease (AD). The blood-brain barrier (BBB) is essential for keeping toxic substances from entering brain tissues. However, the effect of P. gingivalis bacteremia on BBB permeability and its underlying mechanism remains unclear. In the present study, rats were injected by tail vein with P. gingivalis three times a week for eight weeks to induce bacteremia. An in vitro BBB model infected with P. gingivalis was also established. We found that the infiltration of Evans blue dye and Albumin protein deposition in the rat brain tissues were increased in the rat brain tissues with P. gingivalis bacteremia and P. gingivalis could pass through the in vitro BBB model. Caveolae were detected after P. gingivalis infection in BMECs both in vivo and in vitro. Caveolin-1 (Cav-1) expression was enhanced after P. gingivalis infection. Downregulation of Cav-1 rescued P. gingivalis-enhanced BMECs permeability. We further found P. gingivalis-gingipain could be colocalized with Cav-1 and the strong hydrogen bonding between Cav-1 and arg-specific-gingipain (RgpA) were detected. Moreover, P. gingivalis significantly inhibited the major facilitator superfamily domain containing 2a (Mfsd2a) expression. Mfsd2a overexpression reversed P. gingivalis-increased BMECs permeability and Cav-1 expression. These results revealed that Mfsd2a/Cav-1 mediated transcytosis is a key pathway governing BBB BMECs permeability induced by P. gingivalis, which may contribute to P. gingivalis/virulence factors entrance and the subsequent neurological impairments.
Animals ; Rats ; Bacteremia/metabolism* ; Blood-Brain Barrier/microbiology* ; Caveolin 1/metabolism* ; Gingipain Cysteine Endopeptidases/metabolism* ; Permeability ; Porphyromonas gingivalis/pathogenicity* ; Transcytosis ; Virulence Factors/metabolism*

Objective: To detect and analyze the characteristics of oral microbiota in species composition, function and metabolism among caries, periodontitis and oral healthy individuals, hunting for the microbiome-derived biomarkers with specificity and sensitivity to estimate the occurrence of these two diseases. Methods: Saliva samples were collected from 10 patients with high caries risk [decayed-missing-filled teeth (DMFT)≥6, HC group] in Department of Endodontics, 10 patients with periodontitis of grade Ⅱ A-Ⅲ C (PG group) in Department of Periodontology and 10 oral healthy individuals (HH group) from School of Stomatology, The Fourth Military Medical University during from March 2022 to June 2022. A baseline examination was conducted on all participants, including their oral conditions of caries and periodontal health. Metagenomic sequencing (Illumina PE150 platform) and liquid chromatography-mass spectrometry were used to detect microorganisms and their metabolites in the samples respectively. The sequencing data were analyzed to obtain the information of microbial taxonomic composition, functional genes and metabolites in each group of samples. The basic oral conditions and saliva samples of subjects in each group were evaluated and collected by the same professional endodontist. Results: There were no significant difference in baseline characteristics such as age and sex among the subjects in each group (P>0.05). DMFT in HC group (9.0±1.7) was significantly higher than that in HH group (0) and PG group (0) (F=243.00, P<0.001). Sequencing data analysis showed that the taxonomic compositions of salivary microbiota in each group were mainly Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria and Fusobacteria at the phylum level, and Streptococcus, Neisseria, Rothia, Prevotella at the genus level. Differential analysis showed that, compared with the HH group, HC group and PG group had significant differences in taxonomic composition (P<0.05), and the most significant among them was Prevotella. At the species level, Prevotella pallens was the most significant change in HC group, and Porphyromonas gingivalis in PG group. Metabolite analysis showed that there were significant differences in metabolites between HC group and PG group. The results showed that, compared with the HH group, the most significant metabolite change was 3-hydroxy-1, 5-diphenylpentan-1-one in HC group (P=0.001) and N1 acetylspermine in PG group (P=0.002) respectively. Compared with the PG group, the metabolite of HC group with the most significant difference is D-glucosamine 6-phosphate (P=0.006). The metabolism gene function analysis showed that, the enrichment of carbohydrate metabolism related genes was highest in HC group, followed with HH group, and it was lowest in PG group. In addition, compared with the HH group, the abundance of functional genes related to glucose metabolism, such as ABC transporter and phosphotransferase system, were significantly decreased in PG group (P<0.05), but significantly increased in HC group (P<0.05). Conclusions: There is a significant correlation between the alternation of carbohydrate metabolism of salivary microbiota with the occurrence of caries and periodontitis. In the future, Prevotella pallens and 3-hydroxy-1, 5-diphenylpentan-1-one may be the potential biomarkers of caries; while Porphyromonas gingivalis and N1 acetylspermine work in the predictions of periodontitis.
Humans ; Saliva/microbiology* ; Dental Caries Susceptibility ; Periodontitis/microbiology* ; Microbiota/genetics* ; Porphyromonas gingivalis/genetics* ; RNA, Ribosomal, 16S/genetics*

OBJECTIVES: This study aimed to explore the functions and potential regulatory targets of local macrophages in nonalcoholic fatty liver combined with Porphyromonas gingivalis (P. gingivalis)infection. METHODS: Single-cell RNA sequencing was used to analyze the phenotypes and functional changes in various cells in the liver tissue of nonalcoholic steatohepatitis (NASH) mice fed with P. gingivalis. Real-time polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay, and immunofluorescence staining were applied to observe the inflammation and expression levels of macrophage antigen presenting functional markers in the NASH liver. Oil red staining was performed to observe the accumulation of local adipose tissue in the NASH liver. Results were verified through RT-PCRand RNA sequencing using P. gingivalis-lipopolysaccharide treated mouse peritoneal macrophages. RESULTS: In comparison with healthy livers with Kupffer cells, the NASH liver combined with P. gingivalis infection-related macrophages showed significant heterogeneity. C1qb, C1qc, Mafb, Apoe, and Cd14 were highly expressed, but Cd209a, H2-Aa, H2-Ab1, and H2-DMb1, which are related to the antigen presentation function, were weakly expressed. Further in vivo and in vitro investigations indicated that the activation and infiltration of these macrophages may be due to local P. gingivalis-lipopolysaccharide accumulation. CONCLUSIONS P. gingivalis-lipopolysaccharide induces a local macrophage immunotolerance phenotype in nonalcoholic fatty liver, which may be the key mechanism of periodontitis pathogen infection that promotes NASH inflammation and pathogenesis. This study further clarifies the dysfunction and regulatory mechanisms of macrophages in the pathogenesis of P. gingivalis-infected NASH, thereby providing potential therapeutic targets for its clinical treatment.
Mice ; Animals ; Non-alcoholic Fatty Liver Disease/pathology* ; Kupffer Cells/pathology* ; Porphyromonas gingivalis ; Lipopolysaccharides/metabolism* ; Inflammation/pathology* ; Macrophages/metabolism* ; Mice, Inbred C57BL

While several previous studies have indicated the link between periodontal disease (PD) and myocardial infarction (MI), the underlying mechanisms remain unclear. Autophagy, a cellular quality control process that is activated in several diseases, including heart failure, can be suppressed by Porphyromonas gingivalis (P.g.). However, it is uncertain whether autophagy impairment by periodontal pathogens stimulates the development of cardiac dysfunction after MI. Thus, this study aimed to investigate the relationship between PD and the development of MI while focusing on the role of autophagy. Neonatal rat cardiomyocytes (NRCMs) and MI model mice were inoculated with wild-type P.g. or gingipain-deficient P.g. to assess the effect of autophagy inhibition by P.g. Wild-type P.g.-inoculated NRCMs had lower cell viability than those inoculated with gingipain-deficient P.g. This study also revealed that gingipains can cleave vesicle-associated membrane protein 8 (VAMP8), a protein involved in lysosomal sensitive factor attachment protein receptors (SNAREs), at the 47th lysine residue, thereby inhibiting autophagy. Wild-type P.g.-inoculated MI model mice were more susceptible to cardiac rupture, with lower survival rates and autophagy activity than gingipain-deficient P.g.-inoculated MI model mice. After inoculating genetically modified MI model mice (VAMP8-K47A) with wild-type P.g., they exhibited significantly increased autophagy activation compared with the MI model mice inoculated with wild-type P.g., which suppressed cardiac rupture and enhanced overall survival rates. These findings suggest that gingipains, which are virulence factors of P.g., impair the infarcted myocardium by cleaving VAMP8 and disrupting autophagy. This study confirms the strong association between PD and MI and provides new insights into the potential role of autophagy in this relationship.
Mice ; Rats ; Animals ; Porphyromonas gingivalis ; Gingipain Cysteine Endopeptidases ; Autophagosomes ; Myocardium ; Periodontal Diseases ; Heart Rupture

OBJECTIVE: To study the binding target of photosensitizer and bacteria in antimicrobial photodynamic therapy with computer-simulated target prediction and molecular docking research methods and to calculate the binding energy. METHODS: The protein names of Porphyromonas gingivalis (Pg) were obtained and summarized in Uniprot database and RCSB PDB database; the structure diagrams of methy-lene blue were screened in SciFinder database, PubChem database, ChemSpider database, and Chemical Book, and ChemBioDraw software was used to draw and confirm the three-dimensional structure for target prediction and Cytoscape software was used to build a visual network diagram; a protein interaction network was searched and built between the methylene blue target and the common target of Pg in the String database; then we selected FimA, Mfa4, RgpB, and Kgp K1 proteins, used AutoDock software to calculate the docking energy of methylene blue and the above-mentioned proteins and performed molecular docking. RESULTS: The target prediction results showed that there were 19 common targets between the 268 potential targets of methylene blue and 1 865 Pg proteins. The 19 targets were: groS, radA, rplA, dps, fabH, pyrG, thyA, panC, RHO, frdA, ileS, bioA, def, ddl, TPR, murA, lepB, cobT, and gyrB. The results of the molecular docking showed that methylene blue could bind to 9 sites of FimA protein, with a binding energy of -6.26 kcal/mol; with 4 sites of Mfa4 protein and hydrogen bond formation site GLU47, and the binding energy of -5.91 kcal/mol, the binding energy of LYS80, the hydrogen bond forming site of RgpB protein, was -5.14 kcal/mol, and the binding energy of 6 sites of Kgp K1 protein and the hydrogen bond forming site GLY1114 of -5.07 kcal/mol. CONCLUSION Computer simulation of target prediction and molecular docking technology can initially reveal the binding, degree of binding and binding sites of methylene blue and Pg proteins. This method provides a reference for future research on the screening of binding sites of photosensitizers to cells and bacteria.
Computer Simulation ; Methylene Blue ; Molecular Docking Simulation ; Photosensitizing Agents ; Porphyromonas gingivalis

Objectives: To study the effects of Porphyromonas gingivalis (Pg) injected through tail vein on the molecular expression levels of biomarkers of neural stem cells (NSC) and neurons in the hippocampus of wild-type adult rats, and the effects on hippocampal neurogenesis. Methods: Eighteen male Sprague-Dawley (SD) rats were randomly divided into 3 groups based on the table of random numbers (n=6 in each group). In low-intensity group and high-intensity group, rats were injected intravenously through tail vein with 200 μl Pg ATCC33277 [1.0×10³ and 1.0×10⁸ colony forming unit (CFU), respectively] 3 times per week for 8 weeks. In the sham group, 200 μl of phosphate buffer saline (PBS) was given instead. Behavioral tests: the navigation and the exploration tests using Morris water maze (MWM) were applied to evaluate learning and memory ability of rats. Immunohistochemistry was performed to detect cells positively expressing nestin, doublecortin (DCX) and neuronal nuclei (NeuN) in the subgranular zone (SGZ) of rats in each group. Western blotting was used to evaluate the expression levels of nestin, DCX and NeuN in rat hippocampus. Results: Learning and memory abilities: on day 5 of navigation test, the lagency time was 22.83 (16.00, 38.34) s in the high-intensity group, significantly longer than the sham group [5.59 (5.41, 6.17) s] (t=-11.17, P<0.001). There were no significant differences between the low-intensity group [9.85 (8.75, 21.01) s] and the sham group (t=-6.83, P=0.080). Results in the exploration test showed that, in the high-intensity group, the number of fime crossing over the previous platform area within 60 s was 1.50 (1.00, 2.00), significantly less than the sham group [4.00 (2.75, 4.00)] (t=9.75, P=0.003); no significant differences between the low-intensity group [2.50 (2.00, 3.00)] and the sham one (t=4.50, P=0.382). Immunohistochemistry showed that the nestin⁺ cell density in the low-intensity group [(35.36±4.32) cell/mm²] and high-intensity group [(26.51±5.89) cell/mm²] were significantly lower than the sham group [(59.58±14.15) cell/mm²] (t=24.21, P=0.018; t=33.07, P=0.005); as for the mean absorbance of DCX⁺ cells, the low-intensity group (0.007±0.002) and the high-intensity group (0.006±0.002) were significantly lower than the sham group (0.011±0.001) (t=0.004, P=0.018; t=0.006, P=0.005); compared with the sham group [(1.13±0.14)×10³ cell/mm²], the density of NeuN⁺ neurons in the high-intensity group [(0.75±0.08)×10³ cell/mm²] was significantly reduced (t=0.38, P=0.017), and was not significantly changed in the low-intensity group [(0.88±0.19)×10³ cell/mm²] (t=0.25, P=0.075). Western blotting results showed that, compared with the sham group, the expression levels of nestin, DCX, and NeuN were significantly reduced in the high-intensity group (t=0.74, P<0.001; t=0.18, P=0.014; t=0.35, P=0.008), but were not statistically changed in the low-intensity group (t=0.18, P=0.108; t=0.08, P=0.172; t=0.19, P=0.077). Conclusions: Pg injected through tail vein may reduce learning and memory abilities of wild-type rats, and may reduce the number of nestin, DCX, and NeuN-positive cells, and the protein expression levels of the above molecules in the hippocampus.
Animals ; Biomarkers/metabolism* ; Hippocampus/metabolism* ; Male ; Nestin/metabolism* ; Neural Stem Cells/metabolism* ; Neurons/metabolism* ; Porphyromonas gingivalis/metabolism* ; Rats ; Rats, Sprague-Dawley ; Tail/metabolism*

Objective: To study the effect of microRNA-126 (miR-126) on the polarization of human monocyte-derived macrophages stimulated by Porphyromonas gingivalis (Pg) lipopolysaccharide (LPS). Methods: Macrophages derived from human myeloid leukemia mononuclear cells were stimulated by Pg-LPS (5 mg/L) and by Pg-LPS (5 mg/L) after 24 h-transfection of miR-126 mimic or negative control RNA for 48 h, respectively. Real-time quantitative-PCR (qRT-PCR), enzyme-linked immunosorbent assay (ELISA) and Western blotting were conducted to detect the changes in miR-126, pro-inflammatory factor tumor necrosis factor-α (TNF-α), anti-inflammatory factors interleukin-10 (IL-10), inducible nitric oxide synthase (iNOS), arginase-1 (Arg-1) and M1 polarization-related pathways such as nuclear factor kappa-B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Results: Compared with non-LPS stimulation group (TNF-α: 1.000±0.020, iNOS: 1.125±0.064, miR-126: 1.004±0.113, IL-10: 1.003±0.053, Arg-1: 1.130±0.061), the mRNA levels of TNF-α (3.105±0.278) and iNOS (4.296±0.003) increased significantly (t=6.53, P=0.003; t=42.63, P<0.001, respectively), while miR-126, IL-10 and Arg-1 expressions (0.451±0.038, 0.545±0.004 and 0.253±0.017) decreased significantly (t=7.95, P=0.001; t=7.36, P=0.002; t=11.94, P<0.001, respectively) after Pg-LPS stimulated by human-derived macrophages for 48 h. The protein expression of iNOS, TNF-α, Arg-1 and IL-10 were consistent at mRNA levels. Meanwhile, the expressions of phospho-NF-κB p65 (p-p65), phospho-extracellular signal-regulated kinase (p-ERK) and phospho-p38 MAPK (p-p38) increased significantly, while the expression of Arg-1 decreased significantly. Compared with the negative controls (scramble RNA) (TNF-α: 1.141±0.197, iNOS: 1.173±0.115, IL-10: 1.032±0.138, Arg-1: 0.933±0.044), the mRNA levels of TNF-α (0.342±0.022) and iNOS (0.588±0.085) expressions significantly decreased (t=5.35, P=0.006; t=5.05, P=0.007), while IL-10 (1.786±0.221) and Arg-1 expressions (2.152±0.229) significantly increased (t=3.71, P=0.021; t=6.21, P=0.003) after Pg-LPS stimulation with miR-126 mimic transfection. The relative protein expressions of iNOS, p-p65, p-ERK and p-p38 significantly decreased (t=13.00, P<0.001; t=6.98, P=0.002; t=10.86, P<0.001; t=8.32, P=0.001), while the protein level of Arg-1 significantly increased (t=12.08, P<0.001). Conclusions: Pg-LPS could promote M1 polarization of macrophages. miR-126 might inhibit the effect of Pg-LPS on the M1 polarization of macrophages through down-regulating NF-κB and MAPK signaling pathways.
Cell Polarity ; Humans ; Interleukin-10/metabolism* ; Lipopolysaccharides/pharmacology* ; Macrophage Activation ; Macrophages/drug effects* ; MicroRNAs/metabolism* ; NF-kappa B/metabolism* ; Porphyromonas gingivalis ; RNA, Messenger/metabolism* ; Tumor Necrosis Factor-alpha/metabolism*