Examination of Oral <i>Candida</i> Infection in Primary Sj&#246;gren&#39;s Syndrome Patients

Primary Sj&#246;gren's syndrome (pSS) is an autoimmune disease characterized by symptoms such as dry mouth, dry eyes, and other systematic symptoms. Due ...

Peking University School and Hospital of Stomatology

Matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) has been presented as a superior method for the detection of microorganisms in body fluid samples (e.g., blood, saliva, pus, etc.) However, the performance of MALDI-TOF MS in routine identification of caries-related Lactobacillus isolates from saliva of adult patients with caries has not been determined. In the present study, we introduced a new MALDI-TOF MS system for identification of lactobacilli. Saliva samples were collected from 120 subjects with caries. Bacteria were isolated and cultured, and each isolate was identified by both 16S rRNA sequencing and MALDI-TOF MS. The identification results obtained by MALDI-TOF MS were concordant at the genus level with those of conventional 16S rRNA-based sequencing for 88.6% of lactobacilli (62/70) and 95.5% of non-lactobacilli (21/22). Up to 96 results could be obtained in parallel on a single MALDI target, suggesting that this is a reliable high-throughput approach for routine identification of lactobacilli. However, additional reference strains are necessary to increase the sensitivity and specificity of species-level identification.

Identification of Lactobacillus from the saliva of adult patients with caries using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

High-throughput sequencing has helped to reveal the close relationship between  and periodontal disease, but the roles of subspecies diversity and genomic variation within this genus in periodontal diseases still need to be investigated. We performed a comparative genome analysis of 48  and  isolates that from the same cohort of subjects to identify the main drivers of their pathogenicity and adaptation to different environments. The comparisons were done between two species and between disease and health based on pooled sequences. The results showed that both  and  have highly dynamic genomes and can take up various exogenous factors through horizontal gene transfer. The major differences between disease-derived and health-derived samples of  and  were factors related to genome modification and recombination, indicating that the  isolates from disease sites may be more capable of genomic reconstruction. We also identified genetic elements specific to each sample, and found that disease groups had more unique virulence factors related to capsule and lipopolysaccharide synthesis, secretion systems, proteinases, and toxins, suggesting that strains from disease sites may have more specific virulence, particularly for . The differentially represented pathways between samples from disease and health were related to energy metabolism, carbohydrate and lipid metabolism, and amino acid metabolism, consistent with data from the whole subgingival microbiome in periodontal disease and health. Disease-derived samples had gained or lost several metabolic genes compared to healthy-derived samples, which could be linked with the difference in virulence performance between diseased and healthy sample groups. Our findings suggest that  and  may serve as "crucial substances" in subgingival plaque, which may reflect changes in microbial and environmental dynamics in subgingival microbial ecosystems. This provides insight into the potential of  and  as new predictive biomarkers and targets for effective interventions in periodontal disease.

Population-Genomic Insights into Variation in  and  Isolates and Its Association with Periodontal Disease.

Interactions among bacteria can affect biofilm properties. : Here, we investigated the role of different bacteria in functional dysbiosis of an  polymicrobial subgingival plaque model using both 16S rRNA and metatranscriptomic sequencing. : We found that high-virulence  W83 had greater effects on the symbiotic species than the low-virulence  ATCC33277, and that  exacerbated the effects of W83.  significantly influenced the expression of genes related to metabolic pathways and quorum sensing of commensal oral species in a strain-specific manner.  exerted synergistic effects with  W83 but antagonistic effects with strain ATCC33277, which may regulate the expression of virulence factors of  through the clp regulator. : The interaction networks indicated that the strongest correlation was between  and , which demonstrated their bridge and cornerstone roles in biofilm. Changes in the expression of genes relating to outer membrane proteins in  indicated that the addition of different bacteria can interfere with the co-adherence among  and other partners. : We report here the existence of strain-specific interactions in subgingival plaque, which may enhance our understanding of periodontal micro-ecology and facilitate the development of improved plaque control strategies.

Metatranscriptomic analysis of an  biofilm model reveals strain-specific interactions among multiple bacterial species.

Cell-free based therapy is an effective strategy in regenerative medicine as it avoids controversial issues, such as immunomodulation and stability. Recently, exosomes have been explored as a favorable substitution for stem cell therapy as they exhibit multiple advantages, such as the ability to be endocytosed and innate biocompatibility. This study aimed to investigate the effects of stem cells from human exfoliated deciduous teeth (SHED)-derived exosomes (SHED-Exo) on bone marrow stromal cells (BMSCs) osteogenesis and bone recovery. SHED-Exo were isolated, characterized, and applied to the bone loss area caused by periodontitis in a mouse model. We found that the injection of SHED-Exo restored bone loss to the same extent as original stem cells. Without affecting BMSCs proliferation, SHED-Exo mildly inhibited apoptosis. Moreover, SHED-Exo specifically promoted BMSCs osteogenesis and inhibited adipogenesis compared with SHED-derived conditioned medium. The expression of osteogenic marker genes, alkaline phosphatase activity, and Alizarin Red S staining of BMSCs was significantly increased by co-culturing with SHED-Exo. Moreover, Western blot analysis showed that Runx2, a key transcriptional factor in osteogenic differentiation, and p-Smad5 were upregulated upon SHED-Exo stimulation. Expression of the adipogenic marker PPARγ and the amount of lipid droplets decreased when exosomes were present. Low doses of exosomes inhibited the expression of the inflammatory cytokines IL-6 and TNF-α. In conclusion, SHED-Exo directly promoted BMSCs osteogenesis, differentiation, and bone formation. Therefore, exosomes have the potential to be utilized in the treatment of periodontitis and other bone diseases.

Exosomes derived from human exfoliated deciduous teeth ameliorate adult bone loss in mice through promoting osteogenesis.

Early childhood caries (ECC) is a considerable pediatric and public health problem worldwide. Preceding studies have focused primarily on bacterial diversity at the taxonomic level. Although these studies have provided significant information regarding the connection between dental caries and oral microbiomes, further comprehension of this microbial community's ecological relevance is limited. This study identified the carbon source metabolic differences in dental plaque between children with and without ECC. We compared the microbial community functional diversity in 18 caries-free subjects with 18 severe ECC patients based on sole carbon source usage using a Biolog assay. The anaerobic microbial community in the ECC patients displayed greater metabolic activity than that of the control group. Specific carbon source metabolism differed significantly between the two groups. Subjects from the two groups were well distinguished by cluster and principal component analyses based on discriminative carbon sources. Our results implied that the microbial functional diversity between the ECC patients and healthy subjects differed significantly. In addition, the Biolog assay furthered our understanding of oral microbiomes as a composite of functional abilities, thus enabling us to identify the ecologically relevant functional differences among oral microbial communities.

Differences in carbon source usage by dental plaque in children with and without early childhood caries.

Distant lung metastasis is the main factor that affects the survival rate of patients with salivary adenoid cystic carcinoma (SACC). Anoikis resistance is a feature of tumor cells that easily metastasize. The long non-coding RNA (lncRNA) MRPL23 antisense RNA 1 (MPRL23-AS1) is related to lung metastasis in SACC, but its role in anoikis resistance is unknown. After altering MPRL23-AS1 expression in SACC cells, anoikis resistance was detected by calcein AM/PI staining and annexin V/PI flow cytometry. The apoptosis marker activated caspase-3 and the bcl-2/bax ratio were detected by Western blotting. The relationship between MPRL23-AS1 and the promoter of the potential downstream target gene p19INK4D was identified by chromatin immunoprecipitation (ChIP)-PCR assay. p19INK4D expression in patient tissues was determined using qRT-PCR and immunohistochemistry. The functional experiments showed that MPRL23-AS1 could promote anoikis resistance in vitro. MRPL23-AS1 recruited the EZH2 to the promoter region of p19INK4D, inhibited p19INK4D expression, and promoted tumor cell anoikis resistance. p19INK4D overexpression did not affect anoikis in attached cells; however, it attenuated the anoikis resistance effect of MPRL23-AS1 in suspension cells. p19INK4D expression was significantly lower in SACC tissues than in normal tissues. The novel MRPL23-AS1/p19INK4D axis may be a potential SACC biomarker or therapeutic target.

Long non-coding RNA MRPL23-AS1 suppresses anoikis in salivary adenoid cystic carcinoma in vitro.

Food-derived carbon quantum dots (CQDs) can relatively easily be synthesized and chemically manipulated for a broad spectrum of biomedical applications. However, their toxicity may hinder their actual use. Here, -derived CQDs ., CQD-1 and CQD-2, were synthesized by means of different shredding methods and followed by a microwave-assisted hydrothermal approach. Subsequently, these CQDs were analyzed  and in an  mice model to test their biocompatibility and potential use as bioimaging agents and for activation of osteogenic differentiation. When comparing CQD-1 and CQD-2, it was found that CQD-1 exhibited 7.6 times higher photoluminescent (PL) emission intensity around 411 nm compared to CQD-2. Besides, it was found that the size distribution of CQD-1 was 2.05 ± 0.08 nm, compared with 2.14 ± 0.04 nm for CQD-2. Upon exposure to human bone marrow-derived mesenchymal stem cells (hBMSCs) , CQD-1 was endocytosed into the cytoplasm and significantly increased the differentiation of hBMSCs up to 10 μg mL after 7 and 14 days. Apparently, the presence of relatively low doses of CQD-1 showed virtually no toxic or histological effects in the major organs . In contrast, high doses of CQD-1 (1 mg mL) caused cell death  ranging from 35% on day 1 to 80% on day 3 post-exposure, and activated the apoptotic machinery and increased lymphocyte aggregates in the liver tissue. In conclusion, -derived CQDs have the potential for biomedical applications in bioimaging and activation of stem cells osteogenic differentiation. Therefore, it is postulated that CQD-1 from  remains potential prospective material at appropriate doses and specifications.

 and  toxicological evaluation of carbon quantum dots originating from .

The objective of the study was to evaluate the therapeutic effects of carbon quantum dots (CQDs) in immunomodulation on non-obese diabetic (NOD) mice, as the model for Sjögren's syndrome (SS).

Yeqing Song

Central Laboratory,
National Engineering Laboratory for Digital and Material Technology of Stomatology,
Beijing Key Laboratory of Digital Stomatology,
Central Laboratory, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology

Peking University School and Hospital of Stomatology

Examination of Oral Candida Infection in Primary Sjögren's Syndrome Patients