Single-cell transcriptome dissecting the microenvironment remodeled by PD1 blockade combined with photodynamic therapy in a mouse model of oral carcinogenesis.

Oral squamous cell carcinoma (OSCC) stands as a predominant and perilous malignant neoplasm globally, with the majority of cases originating from oral potential malignant disorders (OPMDs). Despite this, effective strategies to impede the progression of OPMDs to OSCC remain elusive. In this study, we established mouse models of oral carcinogenesis via 4-nitroquinoline 1-oxide induction, mirroring the sequential transformation from normal oral mucosa to OPMDs, culminating in OSCC development. By intervening during the OPMDs stage, we observed that combining PD1 blockade with photodynamic therapy (PDT) significantly mitigated oral carcinogenesis progression. Single-cell transcriptomic sequencing unveiled microenvironmental dysregulation occurring predominantly from OPMDs to OSCC stages, fostering a tumor-promoting milieu characterized by increased Treg proportion, heightened S100A8 expression, and decreased Fib_Igfbp5 (a specific fibroblast subtype) proportion, among others. Notably, intervening with PD1 blockade and PDT during the OPMDs stage hindered the formation of the tumor-promoting microenvironment, resulting in decreased Treg proportion, reduced S100A8 expression, and increased Fib_Igfbp5 proportion. Moreover, combination therapy elicited a more robust treatment-associated immune response compared with monotherapy. In essence, our findings present a novel strategy for curtailing the progression of oral carcinogenesis.

Comprehensive analysis of the oral microbiota and metabolome change in patients of burning mouth syndrome with psychiatric symptoms.

Background: Burning mouth syndrome (BMS) is a chronic idiopathic facial pain with intraoral burning or dysesthesia. BMS patients regularly suffer from anxiety/depression, and the association of psychiatric symptoms with BMS has received considerable attention in recent years. The aims of this study were to investigate the potential interplay between psychiatric symptoms and BMS. Methods: Using 16S rRNA sequencing and liquid chromatography-mass spectrometry (LC/MS) to evaluate the oral microbiota and saliva metabolism of 40 BMS patients [including 29 BMS patients with depression or anxiety symptoms (DBMS)] and 40 age matched healthy control (HC). Results: The oral microbiota composition in BMS exhibited no significant differences from HC, although DBMS manifested decreased α-diversity relative to HC. Noteworthy was the discernible elevation in the abundance of proinflammatory microorganisms within the oral microbiome of individuals with DBMS. Parallel findings in LC/MS analyses revealed discernible disparities in metabolites between DBMS and HC groups. Principal differential metabolites were notably enriched in amino acid metabolism and lipid metabolism, exhibiting associations with infectious and immunological diseases. Furthermore, the integrated analysis underscores a definitive association between the oral microbiome and metabolism in DBMS. Conclusions: This study suggests possible future modalities for better understanding the pathogenesis and personalized treatment plans of BMS.

DRP1 inhibition-mediated mitochondrial elongation abolishes cancer stemness, enhances glutaminolysis, and drives ferroptosis in oral squamous cell carcinoma.

BACKGROUND: Mitochondrial dynamics play a fundamental role in determining stem cell fate. However, the underlying mechanisms of mitochondrial dynamics in the stemness acquisition of cancer cells are incompletely understood. METHODS: Metabolomic profiling of cells were analyzed by MS/MS. The genomic distribution of H3K27me3 was measured by CUT&Tag. Oral squamous cell carcinoma (OSCC) cells depended on glucose or glutamine fueling TCA cycle were monitored by 13C-isotope tracing. Organoids and tumors from patients and mice were treated with DRP1 inhibitors mdivi-1, ferroptosis inducer erastin, or combination with mdivi-1 and erastin to evaluate treatment effects. RESULTS: Mitochondria of OSCC stem cells own fragment mitochondrial network and DRP1 is required for maintenance of their globular morphology. Imbalanced mitochondrial dynamics induced by DRP1 knockdown suppressed stemness of OSCC cells. Elongated mitochondria increased α-ketoglutarate levels and enhanced glutaminolysis to fuel the TCA cycle by increasing glutamine transporter ASCT2 expression. α-KG promoted the demethylation of histone H3K27me3, resulting in downregulation of SNAI2 associated with stemness and EMT. Significantly, suppressing DRP1 enhanced the anticancer effects of ferroptosis. CONCLUSION: Our study reveals a novel mechanism underlying mitochondrial dynamics mediated cancer stemness acquisition and highlights the therapeutic potential of mitochondria elongation to increase the susceptibility of cancer cells to ferroptosis.

Salivary microbiota and metabolic phenotype of patients with recurrent aphthous ulcers.

OBJECTIVES: Recurrent aphthous ulcer (RAU) is a prevalent oral mucosal disease, affecting around 20% of the global population. It can greatly impair the quality of life for affected individuals. However, the exact etiology of RAU remains unknown. SUBJECTS AND METHODS: 16S rRNA sequencing (16S rRNA-seq) and non-targeted liquid chromatography-mass spectrometry (LC-MS) were employed to investigate the salivary microbiota and metabolic phenotype between RAU patients (N = 61) and healthy controls (HCs) (N = 105). RESULTS: Findings from 16S rRNA -seq indicated reduced oral microbial diversity in RAU patients compared to HCs, but increased interactions. Clinical variables did not show any significant association with the overall diversity of oral microbiota in RAU patients. However, significant correlations were observed between specific microorganisms and clinical variables. LC-MS results revealed dysregulation of amino acid, lipid, nucleotide, and caffeine metabolism in RAU patients. Furthermore, correlation analysis of 16S rRNA-seq and LC-MS data revealed a significant association between salivary microbiota and metabolites in RAU patients. CONCLUSIONS: Our study revealed notable differences in salivary microbiota and metabolic profiles between RAU patients and HCs, indicating a strong link between oral microbiota dysbiosis, metabolic disturbances, and the onset and progression of RAU.

Mass cytometry and transcriptomic profiling reveal PD1 blockade induced alterations in oral carcinogenesis.

Oral squamous cell carcinoma is the predominant subtype of head and neck squamous cell carcinoma, characterized by a challenging prognosis. In this study, we established a murine model of oral carcinogenesis using 4-nitroquinoline-1-oxide (4-NQO) induction to investigate the impact of immunotherapy on microenvironmental alterations. Mice in the precancerous condition were randomly divided into two groups: one receiving programmed death-1 (PD1) monoclonal antibody treatment and the other, control immunoglobulin G. Our observations showed that while PD1 blockade effectively delayed the progression of carcinogenesis, it did not completely impede or reverse it. To unravel the underlying reasons for the limited effectiveness of PD1 blockade, we collected tongue lesions and applied mass cytometry (CyTOF) and RNA sequencing (RNA-seq) to characterize the microenvironment. CyTOF analysis revealed an increased macrophage subset (expressing high levels of IFNγ and iNOS) alongside a diminished Th1-like subset (exhibiting low expression of TCF7) and three myeloid-derived suppressor cell subsets (displaying low expression of MHC Class II or IFNγ) following anti-PD1 treatment. Notably, we observed an increased presence of cancer-associated fibroblasts (CAFs) expressing collagen-related genes after PD1 blockade. Furthermore, we found a negative correlation between the infiltration levels of CAFs and CD8+ T cells. These findings were validated in murine tongue tissue slides, and publicly available multi-omics datasets. Our results suggest that CAFs may impair the therapeutic efficacy of PD1 blockade in oral carcinogenesis by the remodeling of the extracellular matrix.

Single-Cell Transcriptomes and Immune Repertoires Reveal the Cell State and Molecular Changes in Pemphigus Vulgaris.

The etiology and pathogenesis of pemphigus vulgaris (PV) entail intricate interactions between immune cells and epithelial cells. However, the specific subtypes of immune cells involved in PV, along with their respective roles, remain elusive. Likewise, the precise functions and mechanisms by which glucocorticoids affect cell types within the disease context require further elucidation. To address these knowledge gaps, we performed 5' single-cell RNA sequencing, combined with V(D)J enrichment on buccal mucosal lesions and peripheral blood samples from treatment-naive patients with PV, in conjunction with post-treatment peripheral blood samples obtained after oral prednisone treatment. Our findings suggest that the IL-1α signaling pathway, myeloid APCs, inflammatory CD8+ resident memory T cells, and dysfunctional CD4+ regulatory T cells are involved in the pathogenesis of PV. Part of these findings were validated by immunohistochemical assays and multiplex immunofluorescence assays. Furthermore, our results highlight the significant impact of prednisone treatment on monocytes and mucosal-associated invariant T cells while revealing a limited effect on CD4+ regulatory T cells. Additionally, we present the CDR3 amino acid sequence of BCR related to PV disease and investigate the characteristics of TCR/BCR clonotypes. In conclusion, our study provides a comprehensive understanding of PV, particularly focusing on the mucosal-dominant type, and sheds light on the effects of glucocorticoids within the PV context. These insights hold promise for the development of new therapeutic strategies in this autoimmune disorder.

Retrieval of a fractured implant abutment screw using a microtube extraction device: A dental technique.

Abutment screw fracture is a mechanical complication associated with the failure of dental implant-supported restorations. Retrieval of fractured abutment screws without damaging the internal surface of implants is challenging and can be time-consuming. Microtube extraction devices are used to remove separated endodontic instruments. This article presents a conservative method of retrieving a fractured implant abutment screw using a microtube device.

Direct immunofluorescence and immune function in patients with oral lichen planus.

Background/Purpose: Direct immunofluorescence and immune function and patients with oral lichen planusThe etiology of oral lichen planus (OLP) is unknown, our purpose was to evaluate the diagnostic value of direct immunofluorescence (DIF) and to investigate the immune functions in OLP. Materials and methods: We enrolled 65 patients with suspected lesions of OLP and 47 controls. In all participants, clinical and serologic testing were conducted. The histopathologic and DIF tests were conducted in 65 patients. The severity of OLP was evaluated by reticular/hyperkeratotic, erosive/erythematous, ulcerative (REU) scoring system. Results: By hematoxylin and eosin (H&E) staining and DIF examination, 71.2% (42/59) were diagnosed as OLP, 28.8% (17/59) were diagnosed as non-OLP. DIF demonstrated 64.3% positive reactivity with 2 distinct distribution patterns and 8 staining patterns. Compared to the controls, serum IgA in OLP was higher (P < 0.01), and serum CD3+ cells, IgM, IgE, C3 and C4 were lower (P < 0.05). Pearson correlation analysis in OLP revealed correlations between REU score and IgM, IgA of DIF (r = 0.54, P = 0.026; and r = 0.56, P = 0.020, respectively), between serum IgG and IgG of DIF (r = 0.51, P = 0.038), between serum CD4+ and the ratio of CD4+/CD8+, IgM in DIF (r = -0.50, P = 0.048; and r = -0.54, P = 0.031, respectively), between serum CD8+ and IgM, IgA in DIF (r = 0.52, P = 0.038; and r = -0.50, P = 0.047, respectively). Conclusion: A combination of H&E test and DIF is useful for the diagnosis of OLP. Compared to controls, immune changes happen to patients with OLP. There are significant associations between the OLP lesions and general cellular and humoral immune status, localized humoral immune response.

Photodynamic therapy combined with laser drilling successfully prevents the recurrence of refractory oral proliferative verrucous leukoplakia.

Oral proliferative verrucous leukoplakia is a potentially malignant disorder with high rates of recurrence and malignant transformation. Proliferative verrucous leukoplakia is often refractory to various treatments, including topical drugs, surgical resection, cryotherapy, and laser therapy. Topical 5-aminolevulinic acid-mediated photodynamic therapy is an innovative and effective treatment for potentially malignant oral disorders and has the potential to control the recurrence of precancerous lesions and cancer. Various pre-treatments or combined therapies have been proposed to increase the efficacy of topical 5-aminolevulinic acid-mediated photodynamic therapy, especially for large, thick, or highly keratinised lesions. We report a case of refractory proliferative verrucous leukoplakia in a 58-year-old female patient who showed rapid recurrence within 1 week of topical 5-aminolevulinic acid-mediated photodynamic therapy despite pre-treatment with microneedle puncture, combined intralesional injection of 5-aminolevulinic acid, and shortened treatment interval. We applied three sessions of topical 5-aminolevulinic acid-mediated photodynamic therapy combined with diode laser drilling pre-treatment at 1-week intervals, which successfully eradicated the lesions without any adverse effects and without any signs of recurrence at the 10-month follow-up. Topical 5-aminolevulinic acid-mediated photodynamic therapy combined with diode laser drilling pre-treatment is safe and well-tolerated and could have synergistic efficacy against refractory oral proliferative verrucous leukoplakia.

PD-1 blockade prevents the progression of oral carcinogenesis.

Oral squamous cell carcinoma (OSCC) is one of the most common malignancies in the head and neck with a poor prognosis. Oral cancer development is a multistep process involving carcinogenesis. Though significant advances in cancer immunotherapy over the years, there is lack of evidence for T-cell exhaustion during oral carcinogenesis. Clinical specimens from healthy donors and patients diagnosed with oral leukoplakia (OLK) or OSCC were collected for immunohistochemical staining with PD-L1, CD86, CD8, PD-1 and CTLA-4 antibodies. Meanwhile, chemically induced mouse models of oral carcinogenesis were constructed with 4-nitroquinolone-N-oxide induction. Exhaustion status of T cells was measured by flow cytometry for spleens and by multiplex immunohistochemistry for formalin-fixed paraffin-embedded lesions in multiple stages of oral carcinogenesis. The efficacy of PD-1 blockade with or without cisplatin treatment was evaluated on the mice in precancerous and OSCC stages. We observed higher expression of PD-1 in the human OLK and OSCC tissues compared with the normal, while low expression CTLA-4 in all oral mucosa tissues. Animal experiments showed that the exhausted CD4+ T cells existed much earlier than exhausted CD8+ T cells, and an increased ratio of stem-like exhausted T cells and partially exhausted T cells were detected in the experimental groups. Besides, the expression of immune checkpoint markers (PDCD1, CTLA4 and HAVCR2) was strongly positively correlated with cytokines (IFNG and IL-2). In summary, T-cell exhaustion plays a vital role in oral carcinogenesis, and PD-1 blockade can prevent the progression of oral carcinogenesis.

Malignant transformation of oral leukoplakia treated with carbon dioxide laser: a meta-analysis.

A series of studies are dedicated to research the clinical outcomes of oral leukoplakia (OLK) treated with carbon dioxide laser (CO2 laser); however, the results vary from studies especially related to recurrence and malignant transformation. Hence, we performed this meta-analysis to precisely evaluate the malignant transformation of OLK dealt with CO2 laser and investigate the association between its malignant transformation and kinds of related risk factors, such as gender, clinical classification, long duration of leukoplakia, and degree of epithelial dysplasia and lesion regions. We performed a systematic search of the Cochrane Library, EMBASE, Pubmed, Web of Science, and SCOPUS. Single-arm rate of the overall risk of malignant transformation in OLK treated with CO2 laser was calculated using the Der-Simonian Liard method. We applied subgroup analysis to compare the risk of malignant transformation according to the degree of epithelial dysplasia, clinical type, and region of OLK. Moreover, a pooled odds ratio (OR) is calculated, along with its 95% confidence interval (CI), to compare the risk of malignant transformation according to patients' gender, tobacco, and alcohol consumption. We used the meta package of R software for quantitative data synthesis and analysis. The rate of malignant transformation of OLK treated with carbon dioxide laser ranged from 0 to 15.38% in included studies. The overall rate of malignant transformation of OLK treated with CO2 laser is 4.50% under the random effect model [95% CI 0.0305-0.0659]. A systematic review of observational studies of OLK reported that the estimated overall (mean) malignant transformation rate was 3.5%, with a wide range between 0.13 and 34.0%. Interestingly, our result revealed that it was the male, homogeneous type, no tobacco consumption, and without alcohol-use who had a higher tendency of malignancy after laser surgery. However, this result lack statistically significant data. Generally speaking, whether oral leukoplakia patients underwent laser surgical treatment or not, it may have little effect on malignant transformation. In addition, we strongly advise that it had better not to perform CO2 laser intervention on OLK patients with the following clinical characteristics: homogeneous type, male, no tobacco consumption, and without alcohol-use. Evidence is still lacking in terms of relationship between malignant transformation and risk factors among OLK patients managed with CO2 laser. Thus, these associations should be further investigated.