γδ T cells in oral diseases.

OBJECTIVE: γδ T cells are a distinct subset of unconventional T cells, which link innate and adaptive immunity by secreting cytokines and interacting with other immune cells, thereby modulating immune responses. As the first line of host defense, γδ T cells are essential for mucosal homeostasis and immune surveillance. When abnormally activated or impaired, γδ T cells can contribute to pathogenic processes. Accumulating evidence has revealed substantial impacts of γδ T cells on the pathogenesis of cancers, infections, and immune-inflammatory diseases. γδ T cells exhibit dual roles in cancers, promoting or inhibiting tumor growth, depending on their phenotypes and the clinical stage of cancers. During infections, γδ T cells exert high cytotoxic activity in infectious diseases, which is essential for combating bacterial and viral infections by recognizing foreign antigens and activating other immune cells. γδ T cells are also implicated in the onset and progression of immune-inflammatory diseases. However, the specific involvement and underlying mechanisms of γδ T cells in oral diseases have not been systematically discussed. METHODS: We conducted a systematic literature review using the PubMed/MEDLINE databases to identify and analyze relevant literature on the roles of γδ T cells in oral diseases. RESULTS: The literature review revealed that γδ T cells play a pivotal role in maintaining oral mucosal homeostasis and are involved in the pathogenesis of oral cancers, periodontal diseases, graft-versus-host disease (GVHD), oral lichen planus (OLP), and oral candidiasis. γδ T cells mainly influence various pathophysiological processes, such as anti-tumor activity, eradication of infection, and immune response regulation. CONCLUSION: This review focuses on the involvement of γδ T cells in oral diseases, with a particular emphasis on the main functions and underlying mechanisms by which γδ T cells influence the pathogenesis and progression of these conditions. This review underscores the potential of γδ T cells as therapeutic targets in managing oral health issues.

Multiple noninvasive auxiliary tests-assisted photodynamic therapy in actinic cheilitis: A case report.

Actinic cheilitis (AC) is recognized as the most common precursor lesion of squamous cell carcinoma (SCC) of the lip, with a higher risk of invasiveness and metastasis. Early accurate diagnosis and appropriate therapy are essential to prevent carcinogenesis and progression of AC. Topical 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT), a non-surgical and minimally invasive modality, has been proposed as an effective treatment for oral potentially malignant diseases (OPMDs) and oral cancers. Herein, we report a 64-year-old female patient with AC on the lower lip who received 3 sessions of ALA-PDT with an interval of 1 week. Multiple noninvasive auxiliary tests including autofluorescence imaging, toluidine blue staining, and aneuploidy with DNA image cytometry (DNA-ICM) using brushing from screening through diagnosis, treatment, and follow-up. The patient successfully showed a complete response with no adverse effects and no evidence of recurrence at the 20-month follow-up. Noninvasive auxiliary tests assisted PDT is attractive and well-tolerated and may have synergistic effects against AC.

Continuous artificial intelligence-assisted DNA aneuploidy cytology for surveilling dysplastic oral leukoplakia treated by photodynamic therapy.

Oral leukoplakia (OLK) is one of the most common potentially malignant disorders. High-risk lesions require early intervention before developing into oral cancer. Photodynamic therapy (PDT) is a noninvasive technique for premalignant lesions. Scalpel biopsy remains a reliable method for monitoring the prognosis of OLK, but it is an invasive procedure with poor reproducibility to suspicious lesions. DNA aneuploidy cytology by oral cytobrush has been proposed as a promising objective and noninvasive tool in screening and diagnosing premalignant and malignant lesions. Here, we discussed the significance of artificial intelligence (AI)-assisted DNA aneuploidy cytology by image cytometry (DNA-ICM) for surveilling non-homogeneous OLK with moderate-to-severe dysplasia that was treated by 5-aminolevulinic acid-mediated PDT (ALA-PDT). The present study provides a scheme of the sequential management and surveillance strategy for OLK.

Developmental synergism in the management of oral potentially malignant disorders.

Oral potentially malignant disorders (OPMDs) are associated with an increased risk of occurrence of cancers of the oral cavity or lips. The unifying theme of OPMDs is their potential risk for cancer development. Therefore, the primary objective of the management should be to prevent carcinogenesis. Beyond diagnosis, current strategies for the management of OPMDs predominantly include non-surgical and surgical interventions and a "watch-and-see" approach, such as disease monitoring or surveillance, and preventive strategies. Though no optimal clinical treatment has gained universal approval for reducing or preventing malignant development of OPMDs. Therefore, an urgent need exits for improved treatment properties and effective predictive markers for OPMDs treatment. This review aims to outline recent synergism regarding to the management of OPMDs. Developing new technologies and improved application parameters to promote the treatment efficacy and a novel management prescription approach to OPMDs are proposed.

Melatonin: a potential therapeutic approach for the management of primary Sjögren's syndrome.

Primary Sjögren's syndrome (pSS) is an autoimmune disease that primarily affects the exocrine glands and is mainly characterized by sicca symptoms of the eyes and mouth. Approximately 30-50% of pSS patients develop systemic multi-organ disorders including malignant lymphoma. The etiology of pSS is not well understood; growing evidence suggests that uncontrolled immune/inflammatory responses, excessive oxidative stress, defected apoptosis, dysregulated autophagy, exosomes, and exogenous virus infections may participate in the pathogenesis of pSS. There is no ideal therapeutic method for pSS; the management of pSS is mainly palliative, which aims to alleviate sicca symptoms. Melatonin, as the main secretory product of the pineal gland, has been evidenced to show various physiological functions, including effects of immunoregulation, capability of antioxidation, moderation of autophagy, suppressive activities of apoptosis, regulative capacity of exosomes, properties of anti-infection, and improvement of sleep. The beneficial effects of melatonin have been already validated in some autoimmune diseases such as multiple sclerosis (MS), type 1 diabetes mellitus (T1DM), systemic lupus erythematosus (SLE), and inflammatory bowel disease (IBD). However, our previous research firstly revealed that melatonin might inhibit pathogenic responses of peripheral Th17 and double-negative (DN) T cells in pSS. More importantly, melatonin administration alleviated the development of pSS in animal models with reduced infiltrating lymphocytes, improved functional activity of salivary gland, and decreased production of inflammatory factors as well as autoantibodies. Owing to the important biological properties reported in melatonin are characteristics closely related to the treatment of pSS; the potential role and underlying mechanisms of melatonin in the administration of pSS are certainly worth further investigations. Consequently, the aim of this review is to give a deep insight to the therapeutic potency of melatonin for pSS.

Autophagy-related 9 homolog B regulates T-cell-mediated immune responses in oral lichen planus.

OBJECTIVES: This study aimed to explore the impacts of autophagy-related 9 homolog B (ATG9B)-mediated autophagy on T-cell immune responses in oral lichen planus. DESIGN: ATG9B expression was detected in lesions and local T cells by immunohistochemical analysis and immunofluorescence assay. The effects of ATG9B-mediated autophagy on T-cell immune responses were explored after ATG9B-overexpression or ATG9B-knockdown lentivirus transfection. A coculture system of activated T cells and lipopolysaccharide-induced keratinocytes was used to simulate the main cell crosstalk in oral lichen planus. RESULTS: The expression of ATG9B upregulated in lesions and local T cells of oral lichen planus, especially in non-erosive oral lichen planus, suggesting that ATG9B may be a diagnostic factor for oral lichen planus. Notably, ATG9B-knockdown T cells of oral lichen planus demonstrated autophagy suppression, enhanced proliferation, and attenuated apoptosis, whereas overexpression of ATG9B showed opposite effects on T cells. In the coculture system of T cells and keratinocytes, ATG9B-knockdown T cells of oral lichen planus, but not ATG9B-overexpression T cells, promoted the proliferation and apoptosis of their cocultured keratinocytes. Additionally, exogenous insulin-like growth factor 1 (IGF1) significantly reversed the apoptosis rates of keratinocytes cocultured with T cells expressing abnormal ATG9B. Furthermore, ATG9B-overexpression T cells showed decreased secretion of interferon-γ and tumor necrosis factor-α in the coculture system. CONCLUSIONS: This study revealed the regulatory roles of ATG9B-mediated T-cell autophagy on T-cell immune responses and crosstalk between T cells and keratinocytes in of oral lichen planus.

Multiple endocrine neoplasia 2A with RET mutation p.Cys611Tyr: A case report.

RATIONALE: Multiple endocrine neoplasia 2A (MEN2A) is a rare autosomal-dominant genetic syndrome, frequently misdiagnosed or neglected clinically, resulting in delayed therapy to patients. PATIENT CONCERNS: A 47-year-old Chinese male patient underwent laparoscopic right adrenal tumorectomy, and postoperative pathology confirmed the tumor as pheochromocytoma (PHEO). He was readmitted to the department of endocrinology and metabolism due to constant increase in carcinoembryonic antigen (CEA) at 5 months after the operation. DIAGNOSIS: The patient was confirmed with medullary thyroid carcinoma (MTC), multiple neck lymph node metastasis, and pituitary microadenoma. The p.Cys611Tyr (c.1832G>A, C611Y) mutation was detected. Therefore, he was diagnosed with MEN2A. INTERVENTIONS: He underwent total thyroidectomy. The gene-sequencing analysis of his family was conducted, and the C611Y mutation was detected in his daughter. OUTCOMES: The level of carcinoembryonic antigen decreased significantly after thyroidectomy in this patient. Long-term follow-up management was conducted. Elevated serum calcitonin and bilateral thyroid nodules were found in his 13-year-old daughter. Thus, MEN2A was highly suspected and she was suggested to undergo total thyroidectomy. CONCLUSION: Patients with MEN2A should be screened regularly and managed by a multidisciplinary team.

Targeting CD47 Inhibits Tumor Development and Increases Phagocytosis in Oral Squamous Cell Carcinoma.

BACKGROUND: Our previous work demonstrated upregulated CD47 in Oral Squamous Cell Carcinoma (OSCC). OBJECTIVE: In the present study, we aimed to investigate the effects of CD47 on tumor cell development and phagocytosis in OSCC and elucidate the underlying mechanisms. METHODS: The proliferation, apoptosis, migration, and invasion of oral cancer cells were analyzed after knocking down the expression of CD47. The effects of CD47 on tumor development were also evaluated using a murine model of OSCC. The involvement of CD47 in the phagocytosis of oral cancer cells was identified. RESULTS: Cell proliferation was suppressed by knocking down the expression of CD47 in human OSCC cell line Cal-27 cells but there was no change in the apoptosis rate. Moreover, impaired expression of CD47 inhibited the migration and invasion of Cal-27 cells. Furthermore, we found that nude mice injected with CD47 knockeddown Cal-27 cells displayed decreased tumor volumes at week 9 compared to xenograft transplantations of blank Cal-27 cells. In addition, in vitro phagocytosis of Cal-27 cells by macrophages was significantly enhanced after the knockdown of CD47, which positively correlated with compromised STAT3/JAK2 signaling. CONCLUSION: In summary, the knockdown of CD47 downregulated the development of OSCC and increased the phagocytosis of Cal-27 cells, indicating that CD47 might be a promising therapeutic target.

Heterogeneity of Outcome Measures Used in Randomized Controlled Trials for the Treatment of Oral Lichen Planus: A Methodological Study.

OBJECTIVE: Oral lichen planus (OLP) is a chronic inflammatory immune disease, recognized as an oral potentially malignant disorder by the World Health Organization. There is considerable controversy over the standardized treatment of OLP, with great diversities in the outcome measures in clinical trials. This methodological study aimed to estimate the degree of consensus on outcome measures in randomized controlled trials (RCTs) for OLP treatment. METHODS: PubMed, Embase, and Cochrane databases were searched to identify RCTs published from 2004 to 2018 about OLP treatment. All the outcome measures and measurement methods mentioned in the trials were extracted and analyzed. RESULTS: After identification of 1087 articles, 88 RCTs were included. A total of 193 single-outcome measures and 119 composite outcome measures were classified into 11 different domains, the chief of which consisted of clinical symptom (78 trials; 88.6%) and clinical score (58 trials; 65.9%). Visual analog scale (65 trials; 73.9%) and Thongprasom scoring system (38 trials; 43.2%) were the predominant measurement methods. Oral health-related quality of life (except for clinical symptoms) accounted for 4.8% of all the outcome measures. CONCLUSIONS: There was high heterogeneity in outcome measures of RCTs for OLP treatment, making it difficult to make valid comparisons between different clinical trials. A core outcome set should be developed and adopted in future trials for OLP treatment.

Omega-3 polyunsaturated fatty acids: a promising approach for the management of oral lichen planus.

BACKGROUND: Oral lichen planus (OLP) is a T-cell-mediated inflammatory disease with a risk of malignant transformation. Although the etiology of OLP is still uncertain, growing evidence suggests that oral microbiota, antigen-specific, and non-specific mechanisms are involved in the pathogenesis of OLP. Antigen-specific mechanisms include antigen presentation, T-cell activation, nuclear factor-kappa B signaling pathway, and cytokine secretion, while non-specific mechanisms consist of matrix metalloproteinases (MMP)-9 upregulation, psychological pressure, oxidative damage, aberrant expression of microRNAs (miRNAs), and autophagy. Till now, there is no cure for OLP, and the main purpose of OLP therapy is symptomatic control. FINDING: Seafood and its derivative omega-3 polyunsaturated fatty acids (n-3 PUFAs) can suppress antigen presentation, T-cell activation, and nuclear factor-kappa B signaling pathway, modulate the overexpressed inflammatory cytokines, inhibit the expression of MMP-9, as well as regulate the expression of miRNAs and autophagy. And they are possible agents for ameliorating psychological disorder and oxidative damage. Moreover, n-3 PUFAs supplementation has a beneficial effect on preventing tumorigenesis. CONCLUSION: n-3 PUFAs consumption may provide a non-toxic, inexpensive administration for OLP.

Expression of programmed cell death-ligand 1 in oral squamous cell carcinoma and oral leukoplakia is associated with disease progress and CD8+ tumor-infiltrating lymphocytes.

OBJECTIVE: In recent years, monoclonal antibodies targeting programmed cell death-ligand 1 (PD-L1) have become a promising cancer immunotherapy. However, the role of PD-L1 in oral squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMDs), including oral leukoplakia (OLK), remains controversial. The aim of the present study was to investigate the expression level of PD-L1 in OSCC and OPMDs, and examine its relationship with CD8 expression and different clinicopathological features. METHOD: Expression of PD-L1 and CD8 were conducted in 41 OSCC, 21 OLK, and 25 normal mucosa samples by immunohistochemistry. Then, the density of PD-L1 expression was measured, and its correlation with CD8 expression and different clinicopathological features was analyzed. RESULTS: PD-L1 protein was detected in 97.6% of OSCC, 61.9% of OLK, and 0% of normal tissues. PD-L1 was highly expressed in human OSCC tissue (P < 0.0001), when compared to both OLK and control tissues. PD-L1 positivity was significantly associated with CD8 density (P < 0.0001, r = 0.8491). The PD-L1 high expression OSCC group displayed a trend for improved overall survival (OS) and disease-free survival (DFS) compared to the low expression group, although the differences were not significant. Moreover, the expression level of PD-L1 in OSCC was positively correlated with the pathological grade (P < 0.0001), but it was independent of age, gender, smoking, drinking, tumor size, lymph node status, or recurrence (P > 0.05). Also, there was a significant upregulation of PD-L1 expression observed in the OLK group compared to the control group (P < 0.0001). PD-L1 positivity in OLK patients was associated with gender and smoking habits (P < 0.05), but it did not correlate with age, drinking, or dysplasia (P > 0.05). CONCLUSION: The upregulation of PD-L1 may be associated with disease progress and CD8+ tumor-infiltrating lymphocytes in oral premalignant and malignant lesions.

Aberrant IGF1-PI3K/AKT/MTOR signaling pathway regulates the local immunity of oral lichen planus.

OBJECTIVES: Oral lichen planus (OLP) is a T cell-mediated immune-related chronic disease, featured by accumulation of T cells and apoptosis of keratinocytes. Insulin-like growth factors 1 (IGF1) signaling, in combination with its downstream PI3K/AKT/MTOR cascade, plays pivotal roles in the regulation of inflammation and immune response. Meanwhile, TRB3 acts as a connective protein in the pathway. This study investigated the possible function of IGF1-PI3K/AKT/MTOR pathway in the local immunity of OLP. METHODS: The expression of phosphorylated IGF1R (p-IGF1R) and TRB3 in lesional tissues of OLP was measured. The effects of T cells pretreated with PI3K inhibitor LY294002, MTOR antagonist rapamycin and exogenous IGF1 on the cell proliferation and apoptosis, as well as supernatant inflammatory cytokine levels were detected in co-culture system of activated T cells and oral keratinocytes, respectively. RESULTS: The expression of p-IGF1R and TRB3 in OLP lesions was significantly increased when compared with controls (P < 0.001). Rapamycin-treated T cells displayed enhanced apoptosis rate and promoted proliferation of their keratinocytes in the co-culture system. Notably, abnormal expression of IFN-γ and IL-4 were detected in supernatant of T cell alone and co-culture system in response to pharmacological modulators of IGF1-PI3K/MTOR pathway. CONCLUSIONS: The aberrant IGF1-PI3K/AKT/MTOR signaling may participate in the immunoregulatory mechanism of OLP, via regulation on the crosstalk between T cells and keratinocytes, as well as imbalanced cytokine networks.

Activated Akt/mTOR-autophagy in local T cells of oral lichen planus.

Oral lichen planus (OLP) is a chronic inflammatory disease regulated by T cell-mediated immune response. Autophagy and its major inhibitory pathway Akt/mTOR participate in T cell metabolism and homeostasis, which has been implicated in autoimmune diseases. In this study, the potential involvement of autophagy and its regulatory Akt/mTOR pathway were investigated in local T cells of OLP. The expression of Akt/mTOR pathway and autophagy-related proteins in OLP local lesions, as well as in T cells, were measured by immunohistochemistry and double-labeling immunofluorescence, respectively. Furthermore, the associations of p-Akt, p-mTOR, ULK1, and LC3B expression with RAE scores representing the disease severity of OLP were assessed. The expression of p-Akt, p-mTOR, ULK1, and LC3B in OLP lesions, as well as in local T cells, was significantly increased compared with that in controls. In addition, the level of LC3B was negatively correlated with RAE scores of OLP, and LC3B was higher in nonerosive OLP than erosive ones and controls. Our results suggested that activated Akt/mTOR-autophagy may have a role in the local T cell-mediated immunoregulatory mechanism of OLP. LC3B might be a valuable marker to monitor the disease severity of OLP.

Icaritin Reduces Oral Squamous Cell Carcinoma Progression via the Inhibition of STAT3 Signaling.

Icaritin, a traditional Chinese medicine, possesses antitumor activity. The current study aimed to investigate icaritin effect and potential mechanism on oral squamous cell carcinoma (OSCC) development. OSCC cells proliferation, apoptosis, and autophagy were analyzed after incubation with icaritin at different concentrations and incubation times. The expressions of proteins related to proliferation, apoptosis, and autophagy, as well as signal transducer and activator of transcription 3 (STAT3) signal network, were also evaluated by western blot. Furthermore, STAT3 was knocked down by siRNA transfection to determine STAT3 role in OSCC cell proliferation and apoptosis. An oral specific carcinogenesis mouse model was used to explore icaritin effect on OSCC in vivo. Icaritin significantly inhibited OSCC proliferation in vitro and reduced the expression of both the cell-cycle progression proteins cyclin A2 and cyclin D1. Besides, icaritin increased cleaved caspase 3 and cleaved poly-(ADP-ribose) polymerase expression leading to apoptosis, and it activated autophagy. Icaritin significantly inhibited the expression of phospho-STAT3 (p-STAT3) in a dose- and time-dependent manner. In the in vivo experiment, the number of malignant tumors in the icaritin-treated group was significantly lower than the control. Overall, icaritin suppressed proliferation, promoted apoptosis and autophagy, and inhibited STAT3 signaling in OSCC in vitro and in vivo. In conclusion, icaritin might be a potential therapeutic agent against OSCC development.

Increased circulating CXCR5+ CD4+ T follicular helper-like cells in oral lichen planus.

BACKGROUND: CD4+ T-helper cell is crucial for the inflammatory autoimmune condition of oral lichen planus (OLP). Recently, the pathogenetic functions of T follicular helper (Tfh) cells, a subtype of CD4+ T-helper cells, have been revealed in autoimmune diseases for their pivotal regulation on humoral immunity. To explore the potential pathophysiological role of Tfh cells in OLP, the expression of circulating Tfh-like cells and its correlations with IL-21 and B cells were investigated. METHODS: The frequencies of CXCR5+ CD4+ Tfh-like cells and CD19+ B cells were analyzed in peripheral blood of patients with OLP and controls by flow cytometry, respectively. Besides, the serum IL-21 concentration was measured using ELISA technology. Furthermore, the correlations of CXCR5+ CD4+ Tfh-like cells with CD19+ B cells and serum IL-21 expression levels were evaluated. RESULTS: This study showed significant increased circulating Tfh-like cells (P < 0.05) and B cells (P < 0.0001), as well as decreased serum IL-21 expression (P < 0.001) in OLP. Besides, the frequency of Tfh-like cells exhibited negative correlation with B cells in OLP (r = -0.435, P < 0.05). In particular, the proportion of CXCR5+ CD4+ Tfh-like cells in peripheral blood mononuclear cells of erosive OLP was higher than non-erosive OLP and controls (P = 0.012 and 0.021, respectively). CONCLUSIONS: Increased circulating Tfh-like cells may be involved in the pathogenesis of OLP through abnormal modulation on B-cell proliferation and IL-21 production, and associated with different clinical forms of OLP.

Autophagy and its implication in human oral diseases.

Macroautophagy/autophagy is a conserved lysosomal degradation process essential for cell physiology and human health. By regulating apoptosis, inflammation, pathogen clearance, immune response and other cellular processes, autophagy acts as a modulator of pathogenesis and is a potential therapeutic target in diverse diseases. With regard to oral disease, autophagy can be problematic either when it is activated or impaired, because this process is involved in diverse functions, depending on the specific disease and its level of progression. In particular, activated autophagy functions as a cytoprotective mechanism under environmental stress conditions, which regulates tumor growth and mediates resistance to anticancer treatment in established tumors. During infections and inflammation, activated autophagy selectively delivers microbial antigens to the immune systems, and is therefore connected to the elimination of intracellular pathogens. Impaired autophagy contributes to oxidative stress, genomic instability, chronic tissue damage, inflammation and tumorigenesis, and is involved in aberrant bacterial clearance and immune priming. Hence, substantial progress in the study of autophagy provides new insights into the pathogenesis of oral diseases. This review outlines the mechanisms of autophagy, and highlights the emerging roles of this process in oral cancer, periapical lesions, periodontal diseases, and oral candidiasis.

Altered Autophagy-Associated Genes Expression in T Cells of Oral Lichen Planus Correlated with Clinical Features.

Oral lichen planus (OLP) is a T cell-mediated inflammatory autoimmune disease. Autophagy has emerged as a fundamental trafficking event in mediating T cell response, which plays crucial roles in innate and adaptive immunity. The present study mainly investigated the mRNA expression of autophagy-associated genes in peripheral blood T cells of OLP patients and evaluated correlations between their expression and the clinical features of OLP. Five differentially expressed autophagy-associated genes were identified by autophagy array. Quantitative real-time RT-PCR results confirmed that IGF1 expression in the peripheral blood T cells of OLP patients was significantly higher than that in controls, especially in female and middle-aged (30-50 years old) OLP patients. In addition, ATG9B mRNA levels were significantly lower in nonerosive OLP patients. However, no significant differences were found in the expression of HGS, ESR1, and SNCA between OLP patients and controls. Taken together, dysregulation of T cell autophagy may be involved in immune response of OLP and may be correlated with clinical patterns.