Tau-RNA complexes inhibit microtubule polymerization and drive disease-relevant conformation change.

Alzheimer's disease and related disorders feature neurofibrillary tangles and other neuropathological lesions composed of detergent-insoluble tau protein. In recent structural biology studies of tau proteinopathy, aggregated tau forms a distinct set of conformational variants specific to the different types of tauopathy disorders. However, the constituents driving the formation of distinct pathological tau conformations on pathway to tau-mediated neurodegeneration remain unknown. Previous work demonstrated RNA can serve as a driver of tau aggregation, and RNA associates with tau containing lesions, but tools for evaluating tau/RNA interactions remain limited. Here, we employed molecular interaction studies to measure the impact of tau/RNA binding on tau microtubule binding and aggregation. To investigate the importance of tau/RNA complexes (TRCs) in neurodegenerative disease, we raised a monoclonal antibody (TRC35) against aggregated tau/RNA complexes. We showed that native tau binds RNA with high affinity but low specificity, and tau binding to RNA competes with tau-mediated microtubule assembly functions. Tau/RNA interaction in vitro promotes the formation of higher molecular weight tau/RNA complexes, which represent an oligomeric tau species. Coexpression of tau and poly(A)45 RNA transgenes in Caenorhabditis elegans exacerbates tau-related phenotypes including neuronal dysfunction and pathological tau accumulation. TRC35 exhibits specificity for Alzheimer's disease-derived detergent-insoluble tau relative to soluble recombinant tau. Immunostaining with TRC35 labels a wide variety of pathological tau lesions in animal models of tauopathy, which are reduced in mice lacking the RNA binding protein MSUT2. TRC-positive lesions are evident in many human tauopathies including Alzheimer's disease, progressive supranuclear palsy, corticobasal degeneration and Pick's disease. We also identified ocular pharyngeal muscular dystrophy as a novel tauopathy disorder, where loss of function in the poly(A) RNA binding protein (PABPN1) causes accumulation of pathological tau in tissue from post-mortem human brain. Tau/RNA binding drives tau conformational change and aggregation inhibiting tau-mediated microtubule assembly. Our findings implicate cellular tau/RNA interactions as modulators of both normal tau function and pathological tau toxicity in tauopathy disorders and suggest feasibility for novel therapeutic approaches targeting TRCs.

Salivary metabolomics in oral potentially malignant disorders and oral cancer patients-a systematic review with meta-analysis.

OBJECTIVES: The aim of this systematic review and meta-analysis is to assess the diagnostic potential of salivary metabolomics in the detection of oral potentially malignant disorders (OPMDs) and oral cancer (OC). MATERIALS AND METHODS: A systematic review was performed in accordance with the 3rd edition of the Centre for Reviews and Dissemination (CRD) and Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. Electronic searches for articles were carried out in the PubMed, Web of Science, and Scopus databases. The quality assessment of the included studies was evaluated using the Newcastle-Ottawa Quality Assessment Scale (NOS) and the new version of the QUADOMICS tool. Meta-analysis was conducted whenever possible. The effect size was presented using the Forest plot, whereas the presence of publication bias was examined through Begg's funnel plot. RESULTS: A total of nine studies were included in the systematic review. The metabolite profiling was heterogeneous across all the studies. The expression of several salivary metabolites was found to be significantly altered in OPMDs and OCs as compared to healthy controls. Meta-analysis was able to be conducted only for N-acetylglucosamine. There was no significant difference (SMD = 0.15; 95% CI - 0.25-0.56) in the level of N-acetylglucosamine between OPMDs, OC, and the control group. CONCLUSION: Evidence for N-acetylglucosamine as a salivary biomarker for oral cancer is lacking. Although several salivary metabolites show changes between healthy, OPMDs, and OC, their diagnostic potential cannot be assessed in this review due to a lack of data. Therefore, further high-quality studies with detailed analysis and reporting are required to establish the diagnostic potential of the salivary metabolites in OPMDs and OC. CLINICAL RELEVANCE: While some salivary metabolites exhibit significant changes in oral potentially malignant disorders (OPMDs) and oral cancer (OC) compared to healthy controls, the current evidence, especially for N-acetylglucosamine, is inadequate to confirm their reliability as diagnostic biomarkers. Additional high-quality studies are needed for a more conclusive assessment of salivary metabolites in oral disease diagnosis.

Biological biomarkers of oral cancer.

The oral squamous cell carcinoma (OSCC) 5 year survival rate of 41% has marginally improved in the last few years, with less than a 1% improvement per year from 2005 to 2017, with higher survival rates when detected at early stages. Based on histopathological grading of oral dysplasia, it is estimated that severe dysplasia has a malignant transformation rate of 7%-50%. Despite these numbers, oral dysplasia grading does not reliably predict its clinical behavior. Thus, more accurate markers predicting oral dysplasia progression to cancer would enable better targeting of these lesions for closer follow-up, especially in the early stages of the disease. In this context, molecular biomarkers derived from genetics, proteins, and metabolites play key roles in clinical oncology. These molecular signatures can help predict the likelihood of OSCC development and/or progression and have the potential to detect the disease at an early stage and, support treatment decision-making and predict treatment responsiveness. Also, identifying reliable biomarkers for OSCC detection that can be obtained non-invasively would enhance management of OSCC. This review will discuss biomarkers for OSCC that have emerged from different biological areas, including genomics, transcriptomics, proteomics, metabolomics, immunomics, and microbiomics.

Wound healing after therapy of oral potentially malignant disorders with a 445-nm semiconductor laser: a randomized clinical trial.

OBJECTIVES: Oral potentially malignant disorders (OPMDs) are the most clinically relevant precursor lesions of the oral squamous cell carcinoma (OSCC). OSCC is one of the 15 most common cancers worldwide. OSCC is with its high rate of mortality an important cause of death worldwide. The diagnosis and therapy of clinically relevant precursor lesions of the OSCC is one of the main parts of prevention of this malignant disease. Targeted therapy is one of the main challenges concerning an oncologically safe tissue removal without overwhelming functional and aesthetic impairment. MATERIALS AND METHODS: In this randomized controlled trial, a newly introduced intraoral 445-nm semiconductor laser (2W; cw-mode; SIROLaser Blue, Dentsply Sirona, Bensheim, Germany) was used in the therapy of OPMDs. Duration and course of wound healing, pain, and scar tissue formation were compared to classical cold blade removal with primary suture by measuring remaining wound area, tissue colorimetry, and visual analogue scale. The study includes 40 patients randomized using a random spreadsheet sequence in two groups (n1 = 20; n2 = 20). RESULTS: This comparative analysis revealed a significantly reduced remaining wound area after 1, 2, and 4 weeks in the laser group compared to the cold blade group (p < 0.05). In the laser group, a significantly reduced postoperative pain after 1 week was measured (p < 0.05). CONCLUSION: Laser coagulation of OPMDs with the investigated 445-nm semiconductor laser is a safe, gentle, and predictable surgical procedure with beneficial wound healing and reduced postoperative discomfort. CLINICAL RELEVANCE: Compared to the more invasive and bloody cold blade removal with scalpel, the 445-nm semiconductor laser could be a new functional less traumatic tool in the therapy of OPMDs. The method should be further investigated with regard to the identification of further possible indications. TRAIL REGISTRATION: German Clinical Trials Register No: DRKS00032626.

The Magic Triangle in Oral Potentially Malignant Disorders: Vitamin D, Vitamin D Receptor, and Malignancy.

OPMDs (oral potentially malignant disorders) are a group of disorders affecting the oral mucosa that are characterized by aberrant cell proliferation and a higher risk of malignant transformation. Vitamin D (VitD) and its receptor (VDR) have been extensively studied for their potential contributions to the prevention and therapeutic management of various diseases and neoplastic conditions, including oral cancer. Observational studies suggest correlations between VitD deficiency and higher cancer risk, worse prognosis, and increased mortality rates. Interestingly, emerging data also suggest a link between VitD insufficiency and the onset or progression of OPMDs. Understanding the role of the VitD-VDR axis not only in established oral tumors but also in OPMDs might thus enable early detection and prevention of malignant transformation. With this article, we want to provide an overview of current knowledge about OPMDs and VitD and investigate their potential association and ramifications for clinical management of OPMDs.

Low-dose arecoline regulates distinct core signaling pathways in oral submucous fibrosis and oral squamous cell carcinoma.

BACKGROUND: Betel nut chewing plays a role in the pathogenesis of oral submucous fibrosis (OSF) and oral squamous cell carcinoma (OSCC). As the major active ingredient of the betel nut, the effect of arecoline and its underlying mechanism to OSF and OSCC pathogenesis remain unclear. METHODS: Next-generation sequencing-based transcriptome and dRRBS analysis were performed on OSF and OSCC cells under low-dose arecoline exposure. Functional analyses were performed to compare the different roles of arecoline during OSF and OSCC pathogenesis, and key genes were identified. RESULTS: In this study, we identified that low-dose arecoline promoted cell proliferation of both NFs and OSCC cells via the acceleration of cell cycle progression, while high-dose arecoline was cytotoxic to both NFs and OSCC cells. We performed for the first time the transcriptome and methylome landscapes of NFs and OSCC cells under low-dose arecoline exposure. We found distinct transcriptome and methylome profiles mediated by low-dose arecoline in OSF and OSCC cells, as well as specific genes and signaling pathways associated with metabolic disorders induced by low-dose arecoline exposure. Additionally, low-dose arecoline displayed different functions at different stages, participating in the modulation of the extracellular matrix via Wnt signaling in NFs and epigenetic regulation in OSCC cells. After exposure to low-dose arecoline, the node roles of FMOD in NFs and histone gene clusters in OSCC cells were found. Meanwhile, some key methylated genes induced by arecoline were also identified, like PTPRM and FOXD3 in NFs, SALL3 and IRF8 in OSCC cells, indicating early molecular events mediated by arecoline during OSF and OSCC pathogenesis. CONCLUSIONS: This study elucidated the contribution of low-dose arecoline to OSF and OSCC pathogenesis and identified key molecular events that could be targeted for further functional studies and their potential as biomarkers.

A review of surgical management of progressive myogenic ptosis.

PURPOSE: Surgical correction of myogenic ptosis is a sophisticated endeavor, as the disease is progressive and the post-operative course is prone to significant complications. We sought to review the literature for repair techniques in different types of myogenic ptosis. METHODS: A PubMed/MEDLINE literature search of publications pertaining to surgical outcomes of progressive myogenic ptosis repair was performed. Studies included were original retrospective studies with a minimum of four patients. RESULTS: A total of 27 articles were identified and divided by etiology of myogenic ptosis; either chronic progressive external ophthalmoplegia (CPEO), oculopharyngeal muscular dystrophy (OPMD), myasthenia gravis (MG), or mixed. Surgical techniques predominantly involved levator advancement, levator resection, frontalis sling, blepharoplasty, and Fasanella-Servat. Success rates ranged from 60.5% to 100%. Significant postoperative complications included ptosis recurrence, under-correction, over-correction, keratopathy, lagophthalmos, sling exposure, and sling infection. CONCLUSION: Like surgical repair for other forms of ptosis, correction of progressive myogenic ptosis is guided by levator excursion. However, myogenic ptosis is especially challenging as it is characterized by worsening ptosis and the loss of protective corneal mechanisms. The goals of care with myogenic ptosis involves repairing ptosis just sufficiently to alleviate visual obstruction while avoiding adverse post-operative complications. This intentional under-correction subsequently increases susceptibility for ptosis recurrence. Myogenic ptosis repair therefore requires delicate balancing between function, sustained repair, and corneal protection.

Assessment of PABPN1 nuclear inclusions on a large cohort of patients and in a human xenograft model of oculopharyngeal muscular dystrophy.

Oculopharyngeal muscular dystrophy (OPMD) is a rare muscle disease characterized by an onset of weakness in the pharyngeal and eyelid muscles. The disease is caused by the extension of a polyalanine tract in the Poly(A) Binding Protein Nuclear 1 (PABPN1) protein leading to the formation of intranuclear inclusions or aggregates in the muscle of OPMD patients. Despite numerous studies stressing the deleterious role of nuclear inclusions in cellular and animal OPMD models, their exact contribution to human disease is still unclear. In this study, we used a large and unique collection of human muscle biopsy samples to perform an in-depth analysis of PABPN1 aggregates in relation to age, genotype and muscle status with the final aim to improve our understanding of OPMD physiopathology. Here we demonstrate that age and genotype influence PABPN1 aggregates: the percentage of myonuclei containing PABPN1 aggregates increases with age and the chaperone HSP70 co-localize more frequently with PABPN1 aggregates with a larger polyalanine tract. In addition to the previously described PRMT1 and HSP70 co-factors, we identified new components of PABPN1 aggregates including GRP78/BiP, RPL24 and p62. We also observed that myonuclei containing aggregates are larger than myonuclei without. When comparing two muscles from the same patient, a similar amount of aggregates is observed in different muscles, except for the pharyngeal muscle where fewer aggregates are observed. This could be due to the peculiar nature of this muscle which has a low level of PAPBN1 and contains regenerating fibers. To confirm the fate of PABPN1 aggregates in a regenerating muscle, we generated a xenograft model by transplanting human OPMD muscle biopsy samples into the hindlimb of an immunodeficient mouse. Xenografts from subjects with OPMD displayed regeneration of human myofibers and PABPN1 aggregates were rapidly present-although to a lower extent-after muscle fiber regeneration. Our data obtained on human OPMD samples add support to the dual non-exclusive models in OPMD combining toxic PABPN1 intranuclear inclusions together with PABPN1 loss of function which altogether result in this late-onset and muscle selective disease.

Clinical and genetic features of a large homogeneous cohort of oculopharyngeal muscular dystrophy patients from the Canary Islands.

BACKGROUND: Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant, late-onset myopathy characterized by ptosis, dysphagia, and progressive proximal limb muscle weakness. The disease is produced by a short expansion of the (GCN)n triplet in the PABPN1 gene. The size of expansion has been correlated to the disease onset and severity. We report the clinical features of a large cohort of OPMD patients harboring the (GCN)15 allele from the Canary Islands. METHODS: A retrospective observational study was performed analyzing the clinical, demographic, and genetic data of 123 OPMD patients. Clinical data from this cohort were compared with clinical data collected in a large European study including 139 OPMD patients. RESULTS: A total of 113 patients (94.2%) carried the (GCN)15 expanded PABN1 allele. Age of symptoms' onset was 45.1 years. The most frequent symptom at onset was ptosis (85.2%) followed by dysphagia (12%). The severity of the disease was milder in the Canary cohort compared to European patients as limb weakness (35.1% vs. 50.4%), the proportion of patients that require assistance for walking or use a wheelchair (9.3% vs. 27.4%), and needed of surgery because of severe dysphagia (4.6% vs. 22.8%) was higher in the European cohort. CONCLUSIONS: Nearly 95% of patients with OPMD from the Canary Islands harbored the (GCN)15 expanded allele supporting a potential founder effect. Disease progression seemed to be milder in the (GCN)15 OPMD Canary cohort than in other cohorts with shorter expansions suggesting that other factors, apart from the expansion size, could be involved in the progression of the disease.

Effectiveness of "OralDETECT": a Repetitive Test-enhanced, Corrective Feedback Method Competency Assessment Tool for Early Detection of Oral Cancer.

Early diagnosis of oral cancer results in less aggressive treatment and improves the quality of life and overall 5-year survival rate. Well-trained dental professionals can play a crucial role in the early detection of oral cancers. The present study aims to determine the effectiveness of the training program "OralDETECT", a spaced repetitive, test-enhanced learning tool with a corrective feedback mechanism for early detection of oral cancer. Thirty-two dentists and 259 dental students from three Malaysian dental schools were involved in this study. All participants were trained and calibrated to recognize oral potentially malignant disorders (OPMD) and oral cancer using "OralDETECT", which is comprised of a series of pre-test, lecture, post-tests and review sessions. The percentage of correct answers (scores) for each test given by the participants was calculated and analysed using a paired t test. It was found that the overall percentage of diagnostic accuracy for both dental professionals and student groups increased to above 80% from the pre-tests to the final post-tests. There was a significant improvement in overall scores between the pre-tests and all three post-tests for the dental professional groups and the student groups. The diagnostic accuracy for individual OPMD and lesions suspicious of oral cancer also increased to above 80% for both groups. The results of our study demonstrate that the "OralDETECT" is an efficient and effective competency tool which can be used to train dental professionals and students for the early detection of OPMD and oral cancer.

A Japanese case of oculopharyngeal muscular dystrophy (OPMD) with PABPN1 c.35G > C; p.Gly12Ala point mutation.

BACKGROUND: Oculopharyngeal muscular dystrophy (OPMD) is a late-onset muscular dystrophy characterised by slowly progressive ptosis, dysphagia, and proximal limb muscle weakness. A common cause of OPMD is the short expansion of a GCG or GCA trinucleotide repeat in PABPN1 gene. CASE PRESENTATION: A 78-year-old woman presented with ptosis and gradually progressive dysphagia. Her son had the same symptoms. A physical examination and muscle imaging (MRI and ultrasound) showed impairment of the tongue, proximal muscles of the upper limbs, and flexor muscles of the lower limbs. Needle-electromyography (EMG) of bulbar and facial muscles revealed a myopathic pattern. Based on the characteristic muscle involvement pattern and needle-EMG findings, we suspected that the patient had OPMD. Gene analysis revealed PABPN1 c.35G > C point mutation, which mimicked the effect of a common causative repeat expansion mutation of OPMD. CONCLUSION: We herein describe the first reported Japanese case of OPMD with PABPN1 point mutation, suggesting that this mutation is causative in Asians as well as in Europeans, in whom it was originally reported.

Proteomic analysis reveals that wildtype and alanine-expanded nuclear poly(A)-binding protein exhibit differential interactions in skeletal muscle.

Oculopharyngeal muscular dystrophy (OPMD) is a late-onset, primarily autosomal dominant disease caused by a short GCN expansion in the PABPN1 (polyadenylate-binding protein nuclear 1) gene that results in an alanine expansion at the N terminus of the PABPN1 protein. Expression of alanine-expanded PABPN1 is linked to the formation of nuclear aggregates in tissues from individuals with OPMD. However, as with other nuclear aggregate-associated diseases, controversy exists over whether these aggregates are the direct cause of pathology. An emerging hypothesis is that a loss of PABPN1 function and/or aberrant protein interactions contribute to pathology in OPMD. Here, we present the first global proteomic analysis of the protein interactions of WT and alanine-expanded PABPN1 in skeletal muscle tissue. These data provide both insight into the function of PABPN1 in muscle and evidence that the alanine expansion alters the protein-protein interactions of PABPN1. We extended this analysis to demonstrate altered complex formation with and loss of function of TDP-43 (TAR DNA-binding protein 43), which we show interacts with alanine-expanded but not WT PABPN1. The results from our study support a model where altered protein interactions with alanine-expanded PABPN1 that lead to loss or gain of function could contribute to pathology in OPMD.

Healthcare Professional in the Loop (HPIL): Classification of Standard and Oral Cancer-Causing Anomalous Regions of Oral Cavity Using Textural Analysis Technique in Autofluorescence Imaging.

Oral mucosal lesions (OML) and oral potentially malignant disorders (OPMDs) have been identified as having the potential to transform into oral squamous cell carcinoma (OSCC). This research focuses on the human-in-the-loop-system named Healthcare Professionals in the Loop (HPIL) to support diagnosis through an advanced machine learning procedure. HPIL is a novel system approach based on the textural pattern of OML and OPMDs (anomalous regions) to differentiate them from standard regions of the oral cavity by using autofluorescence imaging. An innovative method based on pre-processing, e.g., the Deriche-Canny edge detector and circular Hough transform (CHT); a post-processing textural analysis approach using the gray-level co-occurrence matrix (GLCM); and a feature selection algorithm (linear discriminant analysis (LDA)), followed by k-nearest neighbor (KNN) to classify OPMDs and the standard region, is proposed in this paper. The accuracy, sensitivity, and specificity in differentiating between standard and anomalous regions of the oral cavity are 83%, 85%, and 84%, respectively. The performance evaluation was plotted through the receiver operating characteristics of periodontist diagnosis with the HPIL system and without the system. This method of classifying OML and OPMD areas may help the dental specialist to identify anomalous regions for performing their biopsies more efficiently to predict the histological diagnosis of epithelial dysplasia.

Age-Associated Salivary MicroRNA Biomarkers for Oculopharyngeal Muscular Dystrophy.

Small non-coding microRNAs (miRNAs) are involved in the regulation of mRNA stability. Their features, including high stability and secretion to biofluids, make them attractive as potential biomarkers for diverse pathologies. This is the first study reporting miRNA as potential biomarkers for oculopharyngeal muscular dystrophy (OPMD), an adult-onset myopathy. We hypothesized that miRNA that is differentially expressed in affected muscles from OPMD patients is secreted to biofluids and those miRNAs could be used as biomarkers for OPMD. We first identified candidate miRNAs from OPMD-affected muscles and from muscles from an OPMD mouse model using RNA sequencing. We then compared the OPMD-deregulated miRNAs to the literature and, subsequently, we selected a few candidates for expression studies in serum and saliva biofluids using qRT-PCR. We identified 126 miRNAs OPMD-deregulated in human muscles, but 36 deregulated miRNAs in mice only (pFDR < 0.05). Only 15 OPMD-deregulated miRNAs overlapped between the in humans and mouse studies. The majority of the OPMD-deregulated miRNAs showed opposite deregulation direction compared with known muscular dystrophies miRNAs (myoMirs), which are associated. In contrast, similar dysregulation direction was found for 13 miRNAs that are common between OPMD and aging muscles. A significant age-association (p < 0.05) was found for 17 OPMD-deregulated miRNAs (13.4%), whereas in controls, only six miRNAs (1.4%) showed a significant age-association, suggesting that miRNA expression in OPMD is highly age-associated. miRNA expression in biofluids revealed that OPMD-associated deregulation in saliva was similar to that in muscles, but not in serum. The same as in muscle, miRNA expression levels in saliva were also found to be associated with age (p < 0.05). Moreover, the majority of OPMD-miRNAs were found to be associated with dysphagia as an initial symptom. We suggest that levels of specific miRNAs in saliva can mark muscle degeneration in general and dysphagia in OPMD.

Arecoline N-oxide regulates oral squamous cell carcinoma development through NOTCH1 and FAT1 expressions.

Areca nut has been evaluated as a group I carcinogen to humans. However, the exact compounds of areca nut causing oral cancer remain unproven. Previous findings from our lab revealed that arecoline N-oxide (ANO), a metabolite of arecoline, exhibits an oral fibrotic effect in immune-deficient NOD/SCID mice. The aim of this study is to investigate the oral potentially malignant disorders (OPMD) inductive activity between areca-alkaloid arecoline and its metabolite ANO in C57BL/6 mice. Our findings show that ANO showed higher activity in inducing hyperplasia with leukoplakia and collagen deposition in C57BL/6 mice compared with the arecoline treated groups. Importantly, immunohistochemical studies showed significant upregulation of NOTCH1, HES1, FAT1, PCNA, and Ki67 expressions in the pathological hyperplastic part. In addition, in vitro studies showed that upregulation of NOTCH1 and FAT1 expressions in ANO treated HGF-1 and DOK cell models. We found that NOTCH1 regulates TP53 expression from NOTCH1 knockdown oral cancer cells. The DNA damage was significantly increased after arecoline and ANO treatment. Further, we found that arecoline-induced H2AX expression was regulated by FMO3. Altogether, our findings show that ANO exhibited higher toxicity in OPMD activity and play a significant role in the induction of areca nut mediated oral tumorigenesis.

Muscle MRI in a large cohort of patients with oculopharyngeal muscular dystrophy.

BACKGROUND AND OBJECTIVE: Oculopharyngeal muscular dystrophy (OPMD) is a genetic disorder caused by an abnormal expansion of GCN triplets within the PABPN1 gene. Previous descriptions have focused on lower limb muscles in small cohorts of patients with OPMD, but larger imaging studies have not been performed. Previous imaging studies have been too small to be able to correlate imaging findings to genetic and clinical data. METHODS: We present cross-sectional, T1-weighted muscle MRI and CT-scan data from 168 patients with genetically confirmed OPMD. We have analysed the pattern of muscle involvement in the disease using hierarchical analysis and presented it as heatmaps. Results of the scans were correlated with genetic and clinical data. RESULTS: Fatty replacement was identified in 96.7% of all symptomatic patients. The tongue, the adductor magnus and the soleus were the most commonly affected muscles. Muscle pathology on MRI correlated positively with disease duration and functional impairment. CONCLUSIONS: We have described a pattern that can be considered characteristic of OPMD. An early combination of fat replacement in the tongue, adductor magnus and soleus can be helpful for differential diagnosis. The findings suggest the natural history of the disease from a radiological point of view. The information generated by this study is of high diagnostic value and important for clinical trial development.

The Pseudomonas aeruginosa efflux pump MexGHI-OpmD transports a natural phenazine that controls gene expression and biofilm development.

Redox-cycling compounds, including endogenously produced phenazine antibiotics, induce expression of the efflux pump MexGHI-OpmD in the opportunistic pathogen Pseudomonas aeruginosa Previous studies of P. aeruginosa virulence, physiology, and biofilm development have focused on the blue phenazine pyocyanin and the yellow phenazine-1-carboxylic acid (PCA). In P. aeruginosa phenazine biosynthesis, conversion of PCA to pyocyanin is presumed to proceed through the intermediate 5-methylphenazine-1-carboxylate (5-Me-PCA), a reactive compound that has eluded detection in most laboratory samples. Here, we apply electrochemical methods to directly detect 5-Me-PCA and find that it is transported by MexGHI-OpmD in P. aeruginosa strain PA14 planktonic and biofilm cells. We also show that 5-Me-PCA is sufficient to fully induce MexGHI-OpmD expression and that it is required for wild-type colony biofilm morphogenesis. These physiological effects are consistent with the high redox potential of 5-Me-PCA, which distinguishes it from other well-studied P. aeruginosa phenazines. Our observations highlight the importance of this compound, which was previously overlooked due to the challenges associated with its detection, in the context of P. aeruginosa gene expression and multicellular behavior. This study constitutes a unique demonstration of efflux-based self-resistance, controlled by a simple circuit, in a Gram-negative pathogen.

General dentists' knowledge, perceptions, and practices regarding oral potentially malignant disorders and oral cancer in Indonesia.

INTRODUCTION: The most effective means for reducing oral cancer (OC) mortality is by preventing late-stage disease. Early diagnosis can be improved by increasing awareness among healthcare providers, specifically general dental practitioners (GDP). Therefore, our study aimed to assess GDPs' knowledge of OC risk factors and perceived competence in performing conventional oral examination (COE) in routine dental practice. MATERIAL AND METHODS: This was a cross-sectional study conducted in five provinces of Indonesia, namely: Aceh, Banda Aceh (BA); Bandung, West Java (WJ); special district Jakarta (JKT), JKT; Pontianak, West Kalimantan (WK); and Sorong, West Papua (WP). The local Dental Association or Faculty of Dentistry invited the GDPs to attend an education program and complete the survey. RESULTS: One hundred seventy-seven GDPs completed the survey (WJ, n = 63; BA, n = 44, JKT, n = 27; WP, n = 23; and WP, n = 20). A large proportion (164 out of 177, 92.66%) of GDPs felt they had received insufficient training to equip them to diagnose OC and as many as 22.6% (n = 40) did not refer to specialists when they found suspicious mucosal lesions. Notwithstanding the significant regional variations, the majority of Indonesian GDPs self-reported inadequate knowledge and awareness of OC and scarce confidence in performing COE. CONCLUSION: GDP knowledge of OC risk factors and COE is key to improving early diagnosis of OC at a community level. Therefore, it is suggested that the lack of knowledge and confidence of GDPs reported here should be addressed through the national dental curriculum in Indonesia.

Prevalence and risk factors of oral potentially malignant disorders in Indonesia: a cross-sectional study undertaken in 5 provinces.

Detection of subjects with oral potentially malignant disorders in a population is key to early detection of oral cancer (OC) with consequent reduction of cancer-related morbidity and mortality. Our aim was to investigate the prevalence and associated risk factors for OPMD in representative provinces of Indonesia. This cross-sectional study was undertaken in five Indonesian provinces: West Java (WJ), Jakarta (JKT), West Papua (WP), West Kalimantan (WK) and Banda Aceh (BA). Respondents answered a previously validated questionnaire including information on ethnicity, occupation, socioeconomic status (SES), oral health practices, and behaviours associated with oral cancer. An oral examination was undertaken using WHO standardized methodology. Data were analysed using ANOVA, Chi-Square, and logistic regression to assess association between risk factors and mucosal disease. A total of 973 respondents between the ages of 17 and 82 years was enrolled (WJ 35.5%,JKT 13.3% WP 18.3%, WK 9%, BA 23.9%). Tobacco smoking (14.8%), Betel quid (BQ) chewing (12.6%) and alcohol drinking (4%) varied geographically. A well-established OPMD was detected in 137 (14.1%) respondents and 2 (0.2%) presented with chronic ulceration later diagnosed as OC. Leukoplakia was the most common OPMD found (9.7%), while the prevalence of oral submucous fibrosis (OSMF), not previously described in the nation, was 2.3%. Poor knowledge of OC risk factors, poor oral hygiene behaviours, low-income SES and ethnicity were significantly associated with the presence of an OPMD. There is a previously under-reported high prevalence of OPMD in Indonesia. Overall, we found a strong correlation between the presence of an OPMD and individual habituation to known risk factors.

Oral bacteriome and oral potentially malignant disorders: A systematic review of the associations.

INTRODUCTION: Periodontal bacteria can infiltrate the epithelium, activate signaling pathways, induce inflammation, and block natural killer and cytotoxic cells, all of which contribute to the vicious circle of carcinogenesis. It is unknown whether oral dysbiosis has an impact on the etiology or prognosis of OPMD. AIMS: Within this paradigm, this work systemically investigated and reported on the composition of oral microbiota in patients with oral potentially malignant disorders (OPMD) versus healthy controls. METHODS: Observational studies that reported next generation sequencing analysis of oral tissue or salivary samples and found at least three bacterial species were included. Identification, screening, citation analysis, and graphical synthesis were carried out. RESULTS: For oral lichen planus (OLP), the bacteria with the highest abundance were Fusobacterium, Capnocytophaga, Gemella, Granulicatella, Porphyromonas, and Rothia; for oral leukoplakia (OLK), Prevotella. Streptococci levels in OLK and OLP were lower. The usage of alcohol or smoke had no effect on the outcomes. CONCLUSIONS: An increase in periodontal pathogenic bacteria could promote the development and exacerbation of lichen. Effective bacteriome-based biomarkers are worthy of further investigation and application, as are bacteriome-based treatments.