Does estradiol have an impact on the dipeptidyl peptidase IV enzyme activity of the Prevotella intermedia group bacteria?

Current research progress on Prevotella intermedia and associated diseases

Prevotella intermedia is a Gram-negative anaerobic bacterium that is a common pathogen of periodontitis. Recent studies have revealed that P. intermedia is closely associated with a variety of diseases involving multiple systems. Under the action of its virulence factors such as cysteine protease and adhesins, P. intermedia has the ability to bind and invade various host cells including gingival fibroblasts. It can also copolymerize a variety of pathogenic bacteria, leading to interference with the host's immune inflammatory response and causing various diseases. In this article, we review the progress of research on P. intermedia virulence factors and bacterial pathogenesis, and the correlation between P. intermedia and various diseases.

Comparative Binding Study of Gliptins to Bacterial DPP4-like Enzymes for the Treatment of Type 2 Diabetes Mellitus (T2DM)

The role of the gut microbiota and its interplay with host metabolic health, particularly in the context of type 2 diabetes mellitus (T2DM) management, is garnering increasing attention. Dipeptidyl peptidase 4 (DPP4) inhibitors, commonly known as gliptins, constitute a class of drugs extensively used in T2DM treatment. However, their potential interactions with gut microbiota remain poorly understood. In this study, we employed computational methodologies to investigate the binding affinities of various gliptins to DPP4-like homologs produced by intestinal bacteria. The 3D structures of DPP4 homologs from gut microbiota species, including Segatella copri, Phocaeicola vulgatus, Bacteroides uniformis, Parabacteroides merdae, and Alistipes sp., were predicted using computational modeling techniques. Subsequently, molecular dynamics simulations were conducted for 200 ns to ensure the stability of the predicted structures. Stable structures were then utilized to predict the binding interactions with known gliptins through molecular docking algorithms. Our results revealed binding similarities of gliptins toward bacterial DPP4 homologs compared to human DPP4. Specifically, certain gliptins exhibited similar binding scores to bacterial DPP4 homologs as they did with human DPP4, suggesting a potential interaction of these drugs with gut microbiota. These findings could help in understanding the interplay between gliptins and gut microbiota DPP4 homologs, considering the intricate relationship between the host metabolism and microbial communities in the gut.

Oral microbiome changes associated with the menstrual cycle in healthy young adult females

The relationship between the menstrual cycle and the oral microbiome has not been clarified. The purpose of this study was to assess potential changes in the oral microbiome of healthy young adults using 16S rRNA-based sequencing. Eleven females (aged 23–36 years) with stable menstrual cycles and without any oral problems were recruited. Saliva samples were collected before brushing every morning during the menstrual period. Based on basal body temperatures, menstrual cycles were divided into four phases, namely the menstrual, follicular, early luteal, and late luteal phases. Our results showed that the follicular phase had a significantly higher abundance ratio of the Streptococcus genus than the early and late luteal phases, whereas the abundance ratios of the Prevotella 7 and Prevotella 6 genera were significantly lower in the follicular phase than those in the early and late luteal phases and that in the early luteal phase, respectively. Alpha diversity by the Simpson index was significantly lower in the follicular phase than that in the early luteal phase, and beta diversity showed significant differences among the four phases. Using the relative abundance data and copy numbers of the 16S rRNA genes in the samples, the bacterial amounts in the four phases were compared, and we observed that the follicular phase had significantly lower amounts of the Prevotella 7 and Prevotella 6 genera than the menstrual and early luteal phase, respectively. These results indicate reciprocal changes with the Streptococcus genus and Prevotella genera, particularly in the follicular phase. In the present study, we showed that the oral microbiome profiles are affected by the menstrual cycles of healthy young adult females.

The oral microbiome in young women at different stages of periodontitis: Prevotella dominant in stage III periodontitis

Objective

Periodontitis progression is related to the dynamic dysbiosis of oral microbiome. We identified the dominant bacteria and the potential pathway in young women with stage-III periodontitis.

Materials and methods

Samples of subgingival plaque were collected from 26 young women with periodontitis (20 with stage-I and 6 with stage-III). Using 16S rRNA-sequencing, we determined the variation in oral bacterial communities of the two groups, and identified the dominant bacteria of each group. We used the Kyoto Encyclopedia of Genes and Genomes (KEGG) database to evaluate the signaling pathways related to the difference in oral bacterial composition. The role of the dominant bacteria of stage-III periodontitis was investigated in vivo and in vitro using an endoplasmic reticulum stress inhibitor.

Results

Young women with stage-I periodontitis had higher values for the Chao1 Index, Observed Species and Phylogenetic Diversity Whole Tree Index than those for women with stage-III periodontitis. β-diversity analyses revealed that samples could be divided into different groups according to the periodontitis stage. The most representative biomarkers of stage-III periodontitis in young women were bacteria of the phylum Bacteroidetes, its order, family and genera Bacteroidales, Prevotellaceae and Prevotella. The KEGG database revealed that the change in oral bacterial composition of young women with stage-III periodontitis may be related to protein processing in an endoplasmic reticulum pathway. Salubrinal (an endoplasmic reticulum stress regulator) controlled expression of Runx2, Col1a1, Ocn in mouse bone-marrow mesenchymal cells. Salubrinal administration showed that moderate endoplasmic reticulum stress inhibited alveolar bone loss in periodontitis induced by Prevotella intermedia lipopolysaccharide.

Conclusion

Differences between periodontitis stages were noted and bacteria of Prevotella species were abundant in young women with stage-III periodontitis. This phenomenon was related to protein processing in an endoplasmic reticulum pathway.

Relationship between the subgingival microbiome and menopausal hormone therapy use: The Buffalo OsteoPerio study

BACKGROUND

This study investigated the association between menopausal hormone therapy (HT) use and the subgingival microbiome, for which published information is limited.

METHODS

This cross-sectional study included 1270 postmenopausal women, aged 53-81 years, who completed clinical examinations. Detailed information on HT use (type, delivery mode, duration) was obtained from questionnaires. HT use was categorized into three groups (never, former, current). 16S rRNA sequencing was performed on subgingival plaque samples obtained during dental examinations. Operational taxonomic units were centered log2-ratio (CLR) transformed to account for the compositional data structure. Analysis of variance was used to compare mean microbial relative abundances across HT categories with Benjamini-Hochberg correction.

RESULTS

Significantly higher alpha diversity (Shannon Index) and beta diversity (Aitchison distance) was observed in never compared with current HT users (p < 0.05, each). Of the total 245 microbial taxa identified, 18 taxa differed significantly among the three HT groups, 11 of which were higher in current users and seven of which were lower in current users as compared with never users (p < 0.05, each). Differences in relative abundance between never and current HT users were materially unchanged after adjustment for age, body mass index, and oral hygiene.

CONCLUSIONS

Relative abundance of several subgingival bacteria differed significantly between never and current HT users in a cohort of postmenopausal women. Additional studies are needed to determine the extent that these relationships might account for the previously reported inverse association between HT use and periodontal disease in older women.

Prevotella species as oral residents and infectious agents with potential impact on systemic conditions

Oral Prevotella are known as anaerobic commensals on oral mucosae and in dental plaques from early life onwards, including pigmented P. melaninogenica, P. nigrescens, and P. pallens and non-pigmented Prevotella species. Many Prevotella species contribute to oral inflammatory processes, being frequent findings in dysbiotic biofilms of periodontal diseases (P. intermedia, P. nigrescens), cariotic lesions (P. denticola, Alloprevotella (formerly Prevotella) tannerae), endodontic infections (P. baroniae, P. oris, P. multisaccharivorax), and other clinically relevant oral conditions. Over the years, several novel species have been recovered from the oral cavity without knowledge of their clinical relevance. Within this wide genus, virulence properties and other characteristics like biofilm formation seemingly vary in a species- and strain-dependent manner, as shown for the P. intermedia group organisms (P. aurantiaca, P. intermedia, P. nigrescens, and P. pallens). Oral Prevotella species are identified in various non-oral infections and chronic pathological conditions. Here, we have updated the knowledge of the genus Prevotella and the role of Prevotella species as residents and infectious agents of the oral cavity, as well as their detection in non-oral infections, but also gathered information on their potential link to cancers of the head and neck, and other systemic disorders.

Sex Steroid Hormones as a Balancing Factor in Oral Host Microbiome Interactions

Sex steroid hormones (SSH) are cholesterol-derived molecules. They are secreted into saliva and enter the oral cavity, triggering physiological responses from oral tissues, with possible clinical implications, such as gingival inflammation and bleeding. SSH and hormonal changes affect not only oral host cells but also oral microorganisms.

Historically, most research has focused on the effect of hormonal changes on specific bacteria and yeasts. Recently a broader effect of SSH on oral microorganisms was suggested. In order to assess the role of SSH in host-microbe interactions in the oral cavity, this review focuses on how and up to what extent SSH can influence the composition and behavior of the oral microbiome. The available literature was reviewed and a comprehensive hypothesis about the role of SSH in host-microbiome interactions is presented. The limited research available indicates that SSH may influence the balance between the host and its microbes in the oral cavity.

Subgingival microflora in adolescent females with polycystic ovary syndrome and its association with oral hygiene, gingivitis, and selected metabolic and hormonal parameters

OBJECTIVES

Research studies suggest that polycystic ovary syndrome (PCOS) may influence the composition of the oral microflora in women. This study aimed to investigate factors affecting the number of selected periopathogens in a young cohort of females with PCOS and to assess the association between oral hygiene, subgingival microbiome, gingival health, and metabolic and hormonal parameters.

MATERIALS AND METHODS

Thirty-two subjects with PCOS and twenty-three healthy controls aged 15-19 years were examined periodontally by a calibrated dentist. A real-time PCR method was used for the identification of 9 subgingival microorganisms. Subjects with PCOS underwent blood tests for determination of FSH, LH, total testosterone, DHEA-S, estradiol, SHBG, fasting glucose, fasting insulin, and lipid profile.

RESULTS

Gingival index (GI), the proportion of bleeding sites (BOP%), probing depth (PD), and plaque index (PLI) did not differ significantly between cases and healthy age-mates. The control group had significantly higher levels of Peptostreptococcus micros and substantially greater percentage of subjects infected by Treponema denticola. Capnocytophaga gingivalis count was positively correlated with the level of estradiol, while the concentration of HDL-C was negatively correlated with the number of Aggregatibacter actinomycetemcomitans and orange complex bacteria.

CONCLUSIONS

PCOS in young patients was not associated with higher pathogenicity of subgingival biofilms.

CLINICAL RELEVANCE

Further studies are needed to explain the relationship between hormonal and metabolic abnormalities, subgingival microflora, and periodontal health in patients with PCOS.

Quorum sensing molecules regulate epithelial cytokine response and biofilm-related virulence of three Prevotella species

Quorum sensing (QS) signaling regulates the motility, adhesion, and biofilm formation of bacteria, and at the same time activates immune response in eukaryotic organisms. We recently demonstrated that the QS molecule, dihydroxy-2, 3-pentanedione (DPD), and its analogs significantly inhibit estradiol-regulated virulence of Prevotella aurantiaca, one of the four species in the Prevotella intermedia group. Here, we examined the combined effects of estradiol and QS signaling on 1) cytokine response of human gingival keratinocytes (HMK) against whole cell extract (WCE) of P. intermedia, Prevotella nigrescens, and Prevotella pallens, and 2) biofilm formation of these three Prevotella species. All experiments were performed in the presence or absence of estradiol, and with different QS molecules: DPD and its analogs (ethyl-DPD, butyl-DPD, and isobutyl-DPD). Concentrations of interleukin (IL)-1β, -6, and -8 were determined by the Luminex multiplex immunoassay, biofilm mass was quantitatively evaluated by measuring protein concentration via the Bradford method, and the microtopography of biofilms was assessed by scanning electron microscopy (SEM) imaging. Concentrations of IL-6 and IL-8 were elevated when HMK cells were incubated with estradiol and WCE of P. intermedia and P. nigrescens, but decreased when incubated with estradiol and WCE of P. pallens. Butyl-DPD neutralized the estradiol- and WCE-induced regulation of HMK interleukin expression and, at the same time, inhibited the biofilm formation of P. intermedia and P. nigrescens. SEM micrographs revealed a decrease in biofilm mass after application of butyl-DPD, which was most detectable among the P. intermedia ATCC 25611 and P. nigrescens ATCC 33563 and AHN 8293 strains. In conclusion, butyl-DPD analog is able to neutralize the WCE-induced epithelial cytokine response and, at the same time, to inhibit the biofilm formation of P. intermedia and P. nigrescens.

The Potential Role of the Dipeptidyl Peptidase-4-Like Activity From the Gut Microbiota on the Host Health

The Dipeptidyl peptidase-4 (DPP-4) activity influences metabolic, behavioral and intestinal disorders through the cleavage of key hormones and peptides. Some studies describe the existence of human DPP-4 homologs in commensal bacteria, for instance in Prevotella or Lactobacillus. However, the role of the gut microbiota as a source of DPP-4-like activity has never been investigated. Through the comparison of the DPP-4 activity in the cecal content of germ-free mice (GFM) and gnotobiotic mice colonized with the gut microbiota of a healthy subject, we bring the proof of concept that a significant DPP-4-like activity occurs in the microbiota. By analyzing the existing literature, we propose that DPP-4-like activity encoded by the intestinal microbiome could constitute a novel mechanism to modulate protein digestion as well as host metabolism and behavior.

Dipeptidyl peptidase IV and quorum sensing signaling in biofilm-related virulence of Prevotella aurantiaca

Biofilm formation and dipeptidyl peptidase IV (DPPIV) enzyme activity contribute to the virulence of oral bacteria, and these virulence factors are partly regulated by quorum sensing signaling system. We recently demonstrated that estradiol regulates growth properties and DPPIV activity of Prevotella intermedia, Prevotella nigrescens, and Prevotella pallens. Here, we examined the DPPIV dependency of biofilm formation of Prevotella aurantiaca. Three strains (two clinical strains AHN 37505 and 37552 and the type strain CCUG 57723) were incubated in three estradiol concentrations (30, 90, and 120 nmol/L). Regulation of DPPIV activity, biofilm and fimbria formation, and coaggregation of bacterial strains were analyzed after incubation with four concentrations (10 nM, 100 nM, 1 μM, 10 μM) of dihydroxy-2,3-pentaedione (DPD), the universal precursor of autoinducer -2 (AI-2), and analogs (ethyl-DPD, butyl-DPD, and isobutyl-DPD) for 24 h. Estradiol enhanced the planktonic growth, coaggregation, and biofilm formation of P. aurantiaca strains. The whole cell extract of AHN 37505 had the highest DPPIV activity, followed by CCUG 57723 and AHN 37552. Inhibition of DPPIV activity with di-isopropylfluorophosphate suppressed the effect of estradiol on biofilm formation. At 100 nM and 10 μM concentrations of DPD, butyl DPD, and isobutyl DPD, biofilm formation of P. aurantiaca was significantly inhibited. Fimbriae formation was enhanced up to concentrations of 100 nM and 1 μM followed by a significant inhibition at higher concentrations of DPD and all analogs. A slight but significant inhibitory effect of DPD and analogs on DPPIV activity was observed. Our results indicate that DPPIV plays a key role in the estradiol-regulated biofilm formation of P. aurantiaca. Quorum sensing autoinducer DPD and C1-alkyl analogs could inhibit biofilm-related virulence of P. aurantiaca.

The Cholesterol-Lowering Effect of Alisol Acetates Based on HMG-CoA Reductase and Its Molecular Mechanism

This study measured the impact of alisol B 23-acetate and alisol A 24-acetate, the main active ingredients of the traditional Chinese medicine Alismatis rhizoma, on total cholesterol (TC), triglyceride (TG), high density lipoprotein-cholesterol (HDL-C), and low density lipoprotein-cholesterol (LDL-C) levels of hyperlipidemic mice. The binding of alisol B 23-acetate and alisol A 24-acetate to the key enzyme involved in the metabolism of TC, 3-hydroxy-3-methylglutary-coenzyme A (HMG-CoA) reductase, was studied using the reagent kit method and the western blotting technique combined with a molecular simulation technique. According to the results, alisol acetates significantly lower the TC, TG, and LDL-C concentrations of hyperlipidemic mice, while raising HDL-C concentrations. Alisol acetates lower HMG-CoA reductase activity in a dose-dependent fashion, both in vivo and in vitro. Neither of these alisol acetates significantly lower the protein expression of HMG-CoA. This suggests that alisol acetates lower the TC level via inhibiting the activity of HMG-CoA reductase by its prototype drug, which may exhibit an inhibition effect via directly and competitively binding to HMG-CoA. The side chain of the alisol acetate was the steering group via molecular simulation.

Regular consumption of Lactobacillus reuteri-containing lozenges reduces pregnancy gingivitis: an RCT

Aim

This randomized controlled trial assessed the impact of Lactobacillus reuteri on pregnancy gingivitis in healthy women.

Materials and Methods

Forty‐five healthy women (24 test/21 placebo) with pregnancy gingivitis in the third trimester of pregnancy were enrolled. At baseline Gingival Index (GI) and Plaque Index (PlI) were assessed at the Ramfjord teeth and venous blood taken for TNF‐α analysis. Subsequently participants were randomly provided with lozenges to be consumed 2 × daily until birth (approx. 7 weeks) containing ≥10⁸CFU L. reuteri ATCC PTA 5289 and ≥10⁸CFU L. reuteri DSM 17938 (test) or being devoid of L. reuteri (placebo). Within 2 days after birth recording of GI, PlI and blood sampling were repeated.

Results

At baseline, mean GI and mean PlI did not differ significantly between both groups. In the test group mean TNF‐α serum level was significantly (p < 0.02) lower than in the placebo group. At reevaluation, mean GI and mean PlI of the test group were both significantly (p < 0.0001) lower than in the placebo group. Mean TNF‐α serum level did no longer differ significantly between the groups.

Conclusions

The consumption of L. reuteri lozenges may be a useful adjunct in the control of pregnancy gingivitis.