Objective: To investigate whether membrane vesicles (MVs) of Streptococcus mutans （S.mutans） contain autoinducer-2 (AI-2) and to preliminarily explore the effects of these MVs on the growth and biofilm formation of S. mutans. Methods: MVs were isolated from the S. mutans UA159 strain using differential centrifugation. The isolated MVs were characterized by nanoparticle tracking analysis for particle size and concentration and observed by transmission electron microscopy. The presence of AI-2 was identified using the Vibrio harveyi BB170 bioluminescence assay: the BB170 diluent was supplemented with AB medium (control group), MV extract (MVs group), pre-ultrafiltration supernatant (Sup group), or post-ultrafiltration supernatant (Sup-af group). The effects of MVs on growth and biofilm formation were assessed using the S.mutans UA159 strain or a luxS deletion mutant as the control group, compared with experimental groups stimulated with gradient concentrations of MVs (MVs-2.0E+7, MVs-2.0E+8, and MVs-2.0E+9 groups). Growth curves, MTT assay, and colony-forming unit (CFU) counts were used to determine changes in growth capacity. Biofilm formation was evaluated using crystal violet staining, confocal laser scanning microscopy, and the anthrone method for polysaccharide quantification. Results: Enriched S. mutans MVs were successfully obtained, with an average particle size of approximately 94.19 nm and a concentration of 1.87E+11 particles/mL. The bioluminescence assay showed that the luminescence intensity of the Sup group was higher than that of the Sup-af group, and the MVs group exhibited higher intensity than the control group. Assessments via growth curves, MTT assay, and CFU counts indicated no significant differences in the growth capacity of the various S. mutans strains after treatment with different concentrations of MVs. Crystal violet staining quantification and confocal laser scanning microscopy observations revealed that high-concentration MV treatment (2.0E+9 particles/mL group) resulted in lower biofilm mass compared to the control. The anthrone method showed that the production of both water-soluble and water-insoluble polysaccharides was significantly lower in the high-concentration MV group than in the control. Conclusion S. mutans MVs contain the quorum sensing signal molecule AI-2. These MVs do not significantly affect the growth of S. mutans, but they can regulate biofilm formation and exhibit an inhibitory effect at high concentrations.

Pulpitis is a common infective oral disease in clinical situations. The regulatory mechanisms of immune defense in pulpitis are still being investigated. Osteomodulin (OMD) is a small leucine-rich proteoglycan family member distributed in bones and teeth. It is a bioactive protein that promotes osteogenesis and suppresses the apoptosis of human dental pulp stem cells (hDPSCs). In this study, the role of OMD in pulpitis and the OMD-induced regulatory mechanism were investigated. The OMD expression in normal and inflamed human pulp tissues was detected via immunofluorescence staining. Intriguingly, the OMD expression decreased in the inflammatory infiltration area of pulpitis specimens. The cellular experiments demonstrated that recombined human OMD could resist the detrimental effects of lipopolysaccharide (LPS)-induced inflammation. A conditional Omd knockout mouse model with pulpal inflammation was established. LPS-induced inflammatory impairment significantly increased in conditional Omd knockout mice, whereas OMD administration exhibited a protective effect against pulpitis. Mechanistically, the transcriptome alterations of OMD overexpression showed significant enrichment in the nuclear factor-κB (NF-κB) signaling pathway. Interleukin-1 receptor 1 (IL1R1), a vital membrane receptor activating the NF-κB pathway, was significantly downregulated in OMD-overexpressing hDPSCs. Additionally, the interaction between OMD and IL1R1 was verified using co-immunoprecipitation and molecular docking. In vivo, excessive pulpal inflammation in Omd-deficient mice was rescued using an IL1R antagonist. Overall, OMD played a protective role in the inflammatory response via the IL1R1/NF-κB signaling pathway. OMD may optimize the immunomodulatory functions of hDPSCs and can be used for regenerative endodontics.
Pulpitis/metabolism* ; NF-kappa B/metabolism* ; Animals ; Signal Transduction ; Humans ; Mice ; Mice, Knockout ; Dental Pulp/metabolism* ; Disease Models, Animal ; Lipopolysaccharides

Objective To analyze the correlation between different types of anemia(small cell anemia and nor-mal cell anemia)before operation and pathological features and prognosis of colorectal cancer patients.Methods The clinical data of 130 patients with colorectal cancer who underwent radical surgery in our hospital from March 2018 to February 2021 were retrospectively analyzed.According to the morphology of red blood cells,the patients were divided into group A(70 cases without anemia),group B(18 cases with small cell anemia)and group C(42 cases with normal cell anemia).Pathological features and postoperative 2 a survival rate of the 3 groups were compared.The correlation between preoperative anemia types and pathological features of colorectal cancer was analyzed by Phi coefficient test,and Kaplan-Meier survival curve was drawn to compare the survival rate of the 3 groups.Results There were significant differences in gender,tumor site,tumor diameter and TNM stage distribution among the three groups(P<0.05).The Phi coefficient test showed that preoperative anemia type was correlated with gender,tumor site,tumor diameter,and TNM stage(r = 0.238,0.255,0.266,0.331,P = 0.025,0.015,0.010,0.001).Multivariate Logistic regression analysis showed that tumor diameter≥5 cm,TNM stage Ⅲ-Ⅳ,distant metastasis,lymph node metastasis,preoperative small cell anemia,preoperative normal cell anemia were the risk factors for the prognosis of colorectal cancer after radical surgery(OR>1,P<0.05).The overall survival rate of 2a in group A was higher than that in group C>that in group B(P<0.05).Log-rank test showed that the postoperative survival rate of the three groups was significantly different(P<0.05).Conclusion Preoperative anemia types were correlated with tumor site,tumor diameter,TNM stage and postoperative survival time of colorectal cancer patients,among which preoperative small-cell anemia patients had the lowest survival rate.